Merge branch 'master' into fix/proxytrack-dav-default-doc

Union both sides' expected-skip entries and TESTS-tail additions,
deduplicating and restoring numeric order.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Signed-off-by: Xavier Roche <roche@httrack.com>

.github/workflows/ci.yml

@@ -79,7 +79,10 @@ jobs:
       - name: Build
         run: make -j"$(nproc)"
 
+      # A backstop only: tests/test-timeout.sh bounds each test, and a healthy run
+      # is a minute here, two on macOS. Without it a stall ran to the job's 6h default.
       - name: Test
+        timeout-minutes: 20
         run: |
           jobs=$(( $(nproc) * 2 )); [ "$jobs" -le 16 ] || jobs=16
           make check -j"$jobs"
@@ -119,6 +122,7 @@ jobs:
         run: make -j"$(nproc)"
 
       - name: Test without python3
+        timeout-minutes: 20
         run: |
           set -euo pipefail
           # Hide every python3* so `command -v python3` fails like it does in the
@@ -173,6 +177,7 @@ jobs:
           sudo ifconfig lo0 alias 127.0.0.3 up
 
       - name: Test
+        timeout-minutes: 20
         run: |
           jobs=$(( $(sysctl -n hw.ncpu) * 2 )); [ "$jobs" -le 16 ] || jobs=16
           make check -j"$jobs"
@@ -245,6 +250,7 @@ jobs:
         run: make -j"$(nproc)"
 
       - name: Test
+        timeout-minutes: 20
         run: |
           jobs=$(( $(nproc) * 2 )); [ "$jobs" -le 16 ] || jobs=16
           make check -j"$jobs"
@@ -302,6 +308,7 @@ jobs:
         env:
           ASAN_OPTIONS: detect_leaks=0:abort_on_error=1:halt_on_error=1:strict_string_checks=1:malloc_fill_byte=202:max_malloc_fill_size=2147483647:free_fill_byte=203:max_free_fill_size=2147483647
           UBSAN_OPTIONS: print_stacktrace=1:halt_on_error=1
+        timeout-minutes: 20
         run: |
           jobs=$(( $(nproc) * 2 )); [ "$jobs" -le 16 ] || jobs=16
           make check -j"$jobs"
@@ -345,6 +352,7 @@ jobs:
       - name: Test (offline self-tests under MSan)
         env:
           MSAN_OPTIONS: abort_on_error=1:halt_on_error=1
+        timeout-minutes: 20
         run: |
           set -euo pipefail
           # 01_engine-* only; zlib-dependent self-tests are named 01_zlib-* and
@@ -426,6 +434,7 @@ jobs:
         run: make -j"$(nproc)"
 
       - name: Test
+        timeout-minutes: 20
         run: |
           jobs=$(( $(nproc) * 2 )); [ "$jobs" -le 16 ] || jobs=16
           make check -j"$jobs"
@@ -618,7 +627,12 @@ jobs:
           set -euo pipefail
           git fetch --no-tags origin \
             "+refs/heads/${{ github.base_ref }}:refs/remotes/origin/${{ github.base_ref }}"
-          base="origin/${{ github.base_ref }}"
+          # Merge base, not the branch tip: master moves during a run, and a
+          # tip-relative diff blames its new C on this PR.
+          if ! base="$(git merge-base "origin/${{ github.base_ref }}" HEAD)"; then
+            echo "::error::no merge base with origin/${{ github.base_ref }}; cannot scope the check."
+            exit 1
+          fi
           set +e
           diff="$(git clang-format --binary clang-format-19 --style=file \
                     --diff --extensions c,h "$base")"
@@ -660,6 +674,8 @@ jobs:
           git fetch --no-tags origin \
             "+refs/heads/${{ github.base_ref }}:refs/remotes/origin/${{ github.base_ref }}"
           base="origin/${{ github.base_ref }}"
+          # Three dots: merge-base scoped, so commits landing on master mid-run
+          # are not counted as this PR's.
           changed="$(git diff --name-only "$base"...HEAD)"
           has() { printf '%s\n' "$changed" | grep -qx "$1"; }
           if has man/httrack.1 && ! has html/httrack.man.html; then

.github/workflows/windows-build.yml

@@ -189,25 +189,53 @@ jobs:
           # A wedged crawl must not eat the job's timeout budget. timeout(1)'s
           # signals can't reap a native httrack.exe (MSYS signals don't reach it),
           # so a hang orphaned processes that starved the runner; run_with_timeout
-          # TerminateProcess-es the whole tree. 600s clears the slowest multi-pass
-          # crawl (a few passes at --max-time=120 each).
+          # TerminateProcess-es the whole tree. 600s is unchanged: it clears the
+          # 540s a three-pass crawl may legitimately take under local-crawl.sh's
+          # own watchdogs, against a slowest healthy test here of 39s.
           . ./testlib.sh
+          per_test=600
 
-          pass=0 fail=0 skip=0 failed="" skipped=""
+          # The whole suite must give up before the step timeout above. A cancelled
+          # step keeps neither its log nor the artifacts the later if:always()
+          # steps would upload, so an overrun that ends in a cancel tells us
+          # nothing; failing on our own terms keeps both. Healthy runs take 8-9
+          # min. The check sits between tests, so the step can still reach 25 min
+          # plus one per-test budget, and that worst case stays inside the 45.
+          suite_deadline=1500
+          started=$SECONDS
+
+          # Survives into the artifact even if the tail of the step log does not.
+          progress=suite-progress.log
+          : >"$progress"
+
+          pass=0 fail=0 skip=0 failed="" skipped="" deadline=0
           for t in 00_runnable.test 01_engine-*.test 01_zlib-*.test \
                    *_local-*.test 13_crawl_proxy_https.test 58_watchdog.test \
                    60_crawl-log-salvage.test; do
+            elapsed=$((SECONDS - started))
+            if [ "$elapsed" -ge "$suite_deadline" ]; then
+              echo "::error::suite deadline: ${elapsed}s elapsed, stopping before $t"
+              echo "DEADLINE before $t after ${elapsed}s" >>"$progress"
+              # Per-test start times, so the slow ones are named rather than guessed.
+              sed 's/^/      /' "$progress"
+              deadline=1
+              break
+            fi
+            echo "RUN $t at ${elapsed}s" >>"$progress"
             rc=0
-            run_with_timeout 600 bash "$t" >"$t.log" 2>&1 || rc=$?
+            # Same guard "make check" uses on POSIX, so a wedge is diagnosed the
+            # same way on every platform. It dumps before it kills, which a bare
+            # run_with_timeout cannot: by the time that returns, the tree whose
+            # stack we wanted is already gone.
+            HTTRACK_TEST_TIMEOUT=$per_test bash ./test-timeout.sh "$t" >"$t.log" 2>&1 || rc=$?
             case "$rc" in
               0) pass=$((pass + 1)); echo "PASS $t" ;;
               77) skip=$((skip + 1)) skipped="$skipped $t"; echo "SKIP $t" ;;
               124)
                 fail=$((fail + 1)) failed="$failed $t"
+                # test-timeout.sh has already written the process list, the stacks
+                # and the killed crawl's own logs into $t.log.
                 echo "FAIL $t (timed out, tree killed)"
-                # Re-running a wedge traced would just hang again: salvage the
-                # killed crawl's own logs into the artifact instead.
-                dump_crawl_logs >>"$t.log"
                 tail -n 25 "$t.log" | sed 's/^/      /'
                 ;;
               *)
@@ -215,21 +243,30 @@ jobs:
                 echo "FAIL $t (exit $rc)"
                 # These assert with `test "$(...)" == "..." || exit 1`, which
                 # says nothing at all on failure. Re-run traced, still bounded.
-                run_with_timeout 600 bash -x "$t" >>"$t.log" 2>&1 || true
+                run_with_timeout "$per_test" bash -x "$t" >>"$t.log" 2>&1 || true
                 tail -n 25 "$t.log" | sed 's/^/      /'
                 ;;
             esac
+            echo "$rc $t" >>"$progress"
+            # An orphaned native httrack.exe spins and starves the runner, which
+            # is how this job dies with "lost communication" rather than a plain
+            # timeout. Clear them between tests and name whoever leaked them.
+            reap_leftover_processes "$t" | tee -a "$progress"
           done
           echo "ran=$((pass + fail + skip)) pass=$pass fail=$fail skip=$skip" |
             tee -a "$GITHUB_STEP_SUMMARY"
 
           # Every gate here exits 77, so an all-skipped suite would report green having
           # tested nothing: pin the skips, and floor the passes in case the glob empties.
-          # footer-overflow skips on Windows (needs a path past MAX_PATH); crange pending #581;
-          # webdav-mime needs a reapable background listener, which MSYS cannot give it;
+          # footer-overflow and purge-longpath skip on Windows (need a path past MAX_PATH);
+          # crange pending #581;
+          # webdav-default and webdav-mime need a reapable background listener, which MSYS cannot give them;
           # badmtime needs a filesystem that stores an mtime past gmtime's range;
-          # single-file ends on a GUI half needing htsserver, which this job does not build.
-          expected_skips=" 01_engine-footer-overflow.test 48_local-crange-memresume.test 71_local-crange-repaircache.test 79_local-proxytrack-webdav-mime.test 88_local-proxytrack-badmtime.test 94_local-single-file.test"
+          # single-file ends on a GUI half needing htsserver, which this job does not build;
+          # update-304-leak needs a LeakSanitizer build, which MSVC has no equivalent of.
+          expected_skips=" 01_engine-footer-overflow.test 100_local-purge-longpath.test 114_local-update-304-leak.test 120_local-proxytrack-webdav-default.test 48_local-crange-memresume.test 71_local-crange-repaircache.test 79_local-proxytrack-webdav-mime.test 88_local-proxytrack-badmtime.test 94_local-single-file.test"
+          # First, or the deadline reads as an unexplained shortfall in the gates below.
+          [ "$deadline" -eq 0 ] || { echo "::error::suite did not finish within ${suite_deadline}s"; exit 1; }
           [ "$pass" -ge 90 ] || { echo "::error::only $pass tests passed ($skip skipped)"; exit 1; }
           [ "$skipped" = "$expected_skips" ] || { echo "::error::unexpected skips:$skipped"; exit 1; }
           [ "$fail" -eq 0 ] || { echo "::error::failing:$failed"; exit 1; }

AGENTS.md

@@ -26,12 +26,18 @@ the operational checklist: toolchain, invariants, and how to ship a change.
   check`, or `PATH="<bld>/src:$PATH"` for a manual run.
 - Give new `.test` scripts `set -e`: the older ones predate the rule, so several
   `local-crawl.sh` calls with no `set -e` report PASS on any non-last failure.
-- Never assert with `cmd | grep -q MARKER && fail`. Under `pipefail` the
-  pipeline is non-zero both when `cmd` fails and when `grep -q` matches early
-  and SIGPIPEs it, so the `&&` never fires and a probe that proved nothing reads
-  as "marker absent". Capture the reply, assert the status line it must carry
-  (an empty, truncated or redirected one is marker-free too), then match with a
-  here-string.
+- Run teardown with errexit off: `trap 'set +e; cleanup' EXIT`. Under `set -e` a
+  failing cleanup command becomes the test's exit status (#773). Keep the other
+  signals on their own `trap` line, or errexit stays off for the rest of the run.
+  The guard also resets `$?`, so save it first if teardown reads it.
+- Never pipe into `grep -q`: it exits on the first match, so whatever the
+  producer had left to write takes SIGPIPE, and under `pipefail` that becomes
+  the pipeline's status. `cmd | grep -q M && fail` then never fires and a probe
+  that proved nothing reads as "marker absent"; `cmd | grep -q M || fail` fails
+  a test whose marker was present. bash issues one `write()` per line, so any
+  match that is not on the last line is exposed. Capture the reply, assert the
+  status line it must carry (an empty, truncated or redirected one is
+  marker-free too), then match with a here-string: `grep -q M <<<"$reply"`.
 
 ## Hard invariants
 - **Generated autotools files are NOT in git.** `configure`, every

html/fcguide.html

@@ -237,7 +237,7 @@ Build options:
   x  replace external html links by error pages (--replace-external)
  %x  do not include any password for external password protected websites (%x0 include) (--no-passwords)
  %q *include query string for local files (useless, for information purpose only) (%q0 don't include) (--include-query-string)
-  o *generate output html file in case of error (404..) (o0 don't generate) (--generate-errors)
+  o *save the server's error pages (404..) (o0 discard them) (--generate-errors)
   X *purge old files after update (X0 keep delete) (--purge-old[=N])
 
 Spider options:
@@ -413,7 +413,7 @@ site. Specifically, the defauls are:
   NN  name conversion type (0 *original structure, 1+: see below)
   LN  long names (L1 *long names / L0 8-3 conversion)
   K   keep original links (e.g. http://www.adr/link) (K0 *relative link)
-  o *generate output html file in case of error (404..) (o0 don't generate)
+  o *save the server's error pages (404..) (o0 discard them)
   X *purge old files after update (X0 keep delete)
   bN  accept cookies in cookies.txt (0=do not accept,* 1=accept)
   u check document type if unknown (cgi,asp..) (u0 don't check, * u1 check but /, u2 check always)
@@ -473,11 +473,11 @@ store them with the same names used on the web site.
 URLs within this web site are adjusted to point to the files in the
 mirror.
 
-<pre><b><i>  o *generate output html file in case of error (404..) (o0 don't generate) </i></b></pre>
+<pre><b><i>  o *save the server's error pages (404..) (o0 discard them) </i></b></pre>
 
-<p align=justify> IF there are errors in downloading, create a file that
-indicates that the URL was not found.  This makes browsing go a lot
-smoother.
+<p align=justify> IF a page cannot be downloaded, the error page the
+server sent is saved in its place, so a broken link still lands on the
+site's own 'not found' page.  This makes browsing go a lot smoother.
 
 <pre><b><i>  X *purge old files after update (X0 keep delete) </i></b></pre>
 
@@ -1011,7 +1011,7 @@ Build options:
   LN  long names (L1 *long names / L0 8-3 conversion)
   K   keep original links (e.g. http://www.adr/link) (K0 *relative link)
   x   replace external html links by error pages
-  o *generate output html file in case of error (404..) (o0 don't generate)
+  o *save the server's error pages (404..) (o0 discard them)
   X *purge old files after update (X0 keep delete)
   %x  do not include any password for external password protected websites (%x0 include) (--no-passwords)
   %q *include query string for local files (information only) (%q0 don't include) (--include-query-string)
@@ -1118,9 +1118,9 @@ deactivated byt his process.
 httrack http://www.shoesizes.com -O /tmp/shoesizes -x
 </i></b></pre>
 
-<p align=justify> This option prevents the generation of '404' error
-files to replace files that were not found even though there were URLs
-pointing to them.  It is useful for saving space as well as eliminating
+<p align=justify> This option keeps the server's '404' error pages out
+of the mirror, even though there were URLs pointing to the missing
+files.  It is useful for saving space as well as eliminating
 unnecessary files in operations where a working web site is not the
 desired result. 
 

html/httrack.man.html

@@ -777,8 +777,8 @@ information purpose only) (%q0 don’t include)
 <td width="82%">
 
 
-<p>*generate output html file in case of error (404..) (o0
-don&rsquo;t generate) (--generate-errors)</p></td></tr>
+<p>*save the server&rsquo;s error pages (404..) (o0 discard
+them) (--generate-errors)</p></td></tr>
 <tr valign="top" align="left">
 <td width="9%"></td>
 <td width="4%">

html/step9_opt5.html

@@ -122,7 +122,7 @@ h4 { margin: 0;  font-weight: bold;  font-size: 1.18em; }
   </small><br><br>
 <!-- -->
   <li>No error pages</li>
-  <br><small>Do not generate error pages (if a 404 error occurred, for example)
+  <br><small>Do not save the error pages sent by the server (if a 404 error occurred, for example)
   <br>If a page is missing on the remote site, there will not be any warning on the local site
   </small><br><br>
 <!-- -->

man/httrack.1

@@ -3,7 +3,7 @@
 .\"
 .\" This file is generated by man/makeman.sh; do not edit by hand.
 .\" SPDX-License-Identifier: GPL-3.0-or-later
-.TH httrack 1 "26 July 2026" "httrack website copier"
+.TH httrack 1 "27 July 2026" "httrack website copier"
 .SH NAME
 httrack \- offline browser : copy websites to a local directory
 .SH SYNOPSIS
@@ -220,7 +220,7 @@ do not include any password for external password protected websites (%x0 includ
 .IP \-%g
 strip query keys for dedup ([host/pattern=]key1,key2,...) (\-\-strip\-query <param>)
 .IP \-o
-*generate output html file in case of error (404..) (o0 don't generate) (\-\-generate\-errors)
+*save the server's error pages (404..) (o0 discard them) (\-\-generate\-errors)
 .IP \-X
 *purge old files after update (X0 keep delete) (\-\-purge\-old[=N])
 .IP \-%p

src/hts-indextmpl.h

@@ -487,141 +487,6 @@ regen:
 
 #define HTS_DATA_UNKNOWN_HTML_LEN 0
 
-#define HTS_DATA_ERROR_HTML "<html>"LF\
-  "<html xmlns=\"http://www.w3.org/1999/xhtml\" lang=\"en\">"LF\
-  ""LF\
-  "<head>"LF\
-  "	<meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\" />"LF\
-  "	<meta name=\"description\" content=\"HTTrack is an easy-to-use website mirror utility. It allows you to download a World Wide website from the Internet to a local directory,building recursively all structures, getting html, images, and other files from the server to your computer. Links are rebuiltrelatively so that you can freely browse to the local site (works with any browser). You can mirror several sites together so that you can jump from one toanother. You can, also, update an existing mirror site, or resume an interrupted download. The robot is fully configurable, with an integrated help\" />"LF\
-  "	<meta name=\"keywords\" content=\"httrack, HTTRACK, HTTrack, winhttrack, WINHTTRACK, WinHTTrack, offline browser, web mirror utility, aspirateur web, surf offline, web capture, www mirror utility, browse offline, local  site builder, website mirroring, aspirateur www, internet grabber, capture de site web, internet tool, hors connexion, unix, dos, windows 95, windows 98, solaris, ibm580, AIX 4.0, HTS, HTGet, web aspirator, web aspirateur, libre, GPL, GNU, free software\" />"LF\
-  "	<title>Page not retrieved! - HTTrack Website Copier</title>"LF\
-  "	<style type=\"text/css\">"LF\
-  "	<!--"LF\
-  ""LF\
-  "body {"LF\
-  "	margin: 0;  padding: 0;  margin-bottom: 15px;  margin-top: 8px;"LF\
-  "	background: #77b;"LF\
-  "}"LF\
-  "body, td {"LF\
-  "	font: 14px \"Trebuchet MS\", Verdana, Arial, Helvetica, sans-serif;"LF\
-  "	}"LF\
-  ""LF\
-  "#subTitle {"LF\
-  "	background: #000;  color: #fff;  padding: 4px;  font-weight: bold; "LF\
-  "	}"LF\
-  ""LF\
-  "#siteNavigation a, #siteNavigation .current {"LF\
-  "	font-weight: bold;  color: #448;"LF\
-  "	}"LF\
-  "#siteNavigation a:link    { text-decoration: none; }"LF\
-  "#siteNavigation a:visited { text-decoration: none; }"LF\
-  ""LF\
-  "#siteNavigation .current { background-color: #ccd; }"LF\
-  ""LF\
-  "#siteNavigation a:hover   { text-decoration: none;  background-color: #fff;  color: #000; }"LF\
-  "#siteNavigation a:active  { text-decoration: none;  background-color: #ccc; }"LF\
-  ""LF\
-  ""LF\
-  "a:link    { text-decoration: underline;  color: #00f; }"LF\
-  "a:visited { text-decoration: underline;  color: #000; }"LF\
-  "a:hover   { text-decoration: underline;  color: #c00; }"LF\
-  "a:active  { text-decoration: underline; }"LF\
-  ""LF\
-  "#pageContent {"LF\
-  "	clear: both;"LF\
-  "	border-bottom: 6px solid #000;"LF\
-  "	padding: 10px;  padding-top: 20px;"LF\
-  "	line-height: 1.65em;"LF\
-	" background-image: url(backblue.gif);"LF\
-	" background-repeat: no-repeat;"LF\
-	" background-position: top right;"LF\
-  "	}"LF\
-  ""LF\
-  "#pageContent, #siteNavigation {"LF\
-  "	background-color: #ccd;"LF\
-  "	}"LF\
-  ""LF\
-  ""LF\
-  ".imgLeft  { float: left;   margin-right: 10px;  margin-bottom: 10px; }"LF\
-  ".imgRight { float: right;  margin-left: 10px;   margin-bottom: 10px; }"LF\
-  ""LF\
-  "hr { height: 1px;  color: #000;  background-color: #000;  margin-bottom: 15px; }"LF\
-  ""LF\
-  "h1 { margin: 0;  font-weight: bold;  font-size: 2em; }"LF\
-  "h2 { margin: 0;  font-weight: bold;  font-size: 1.6em; }"LF\
-  "h3 { margin: 0;  font-weight: bold;  font-size: 1.3em; }"LF\
-  "h4 { margin: 0;  font-weight: bold;  font-size: 1.18em; }"LF\
-  ""LF\
-  ".blak { background-color: #000; }"LF\
-  ".hide { display: none; }"LF\
-  ".tableWidth { min-width: 400px; }"LF\
-  ""LF\
-  ".tblRegular       { border-collapse: collapse; }"LF\
-  ".tblRegular td    { padding: 6px;  background-image: url(fade.gif);  border: 2px solid #99c; }"LF\
-  ".tblHeaderColor, .tblHeaderColor td { background: #99c; }"LF\
-  ".tblNoBorder td   { border: 0; }"LF\
-  ""LF\
-  ""LF\
-  "// -->"LF\
-  "</style>"LF\
-  ""LF\
-  "</head>"LF\
-  ""LF\
-  "<table width=\"76%%\" border=\"0\" align=\"center\" cellspacing=\"0\" cellpadding=\"3\" class=\"tableWidth\">"LF\
-  "	<tr>"LF\
-  "	<td id=\"subTitle\">HTTrack Website Copier - Open Source offline browser</td>"LF\
-  "	</tr>"LF\
-  "</table>"LF\
-  "<table width=\"76%%\" border=\"0\" align=\"center\" cellspacing=\"0\" cellpadding=\"0\" class=\"tableWidth\">"LF\
-  "<tr class=\"blak\">"LF\
-  "<td>"LF\
-  "	<table width=\"100%%\" border=\"0\" align=\"center\" cellspacing=\"1\" cellpadding=\"0\">"LF\
-  "	<tr>"LF\
-  "	<td colspan=\"6\"> "LF\
-  "		<table width=\"100%%\" border=\"0\" align=\"center\" cellspacing=\"0\" cellpadding=\"10\">"LF\
-  "		<tr> "LF\
-  "		<td id=\"pageContent\"> "LF\
-  "<!-- ==================== End prologue ==================== -->"LF\
-  "<h1><strong><u>Oops!...</u></strong></h1>"LF\
-  "<h3>This page has <font color=\"red\"><em>not</em></font> been retrieved by HTTrack Website Copier (%s). </h3>"LF\
-  "<script language=\"Javascript\">"LF\
-  "<!--"LF\
-  "  var loc=document.location.toString();"LF\
-  "  if (loc) {"LF\
-  "    var pos=loc.indexOf('link=');"LF\
-  "    if (pos>0) {"LF\
-  "      document.write('Clic to the link <b>below</b> to go to the online location!<br><a href=\"'+loc.substring(pos+5)+'\">'+loc.substring(pos+5)+'</a><br>');"LF\
-  "    } else"LF\
-  "      document.write('(no location defined)');"LF\
-  "  }"LF\
-  "// -->"LF\
-  "</script>"LF\
-  "<h6 align=\"right\">Mirror by HTTrack Website Copier</h6>"LF\
-  "</body>"LF\
-  "</html>"LF\
-  "<!-- ==================== Start epilogue ==================== -->"LF\
-  "		</td>"LF\
-  "		</tr>"LF\
-  "		</table>"LF\
-  "	</td>"LF\
-  "	</tr>"LF\
-  "	</table>"LF\
-  "</td>"LF\
-  "</tr>"LF\
-  "</table>"LF\
-  ""LF\
-  "<table width=\"76%%\" height=\"100%%\" border=\"0\" align=\"center\" valign=\"bottom\" cellspacing=\"0\" cellpadding=\"0\">"LF\
-  "	<tr>"LF\
-  "	<td id=\"footer\"><small>&copy; 2014 Xavier Roche & other contributors - Web Design: Kauler Leto.</small></td>"LF\
-  "	</tr>"LF\
-  "</table>"LF\
-  ""LF\
-  "</body>"LF\
-  ""LF\
-  "</html>"LF\
-  ""LF\
-  ""LF
-
 // image gif "unknown"
 #define HTS_DATA_UNKNOWN_GIF \
   "\x47\x49\x46\x38\x39\x61\x20\x0\x20\x0\xf7\xff\x0\xc0\xc0\xc0\xff\x0\x0\xfc\x3\x0\xf8\x6\x0\xf6\x9\x0\xf2\xc\x0\xf0\xf\x0\xf0\xe\x0\xed\x11\x0\xec\x13\x0\xeb\x14\x0\xe9\x15\x0\xe8\x18\x0\xe6\x18\x0\xe5\x1a\x0\xe3\x1c\x0\xe2\x1d\x0\xe1\x1e\x0\xdf\x20\x0\xdd\x23\x0\xdd\x22\x0\xdb\x23\x0\xda\x25\x0\xd9\x25\x0\xd8\x27\x0\xd6\x29\x0\xd5\x2a\x0\xd3\x2c\x0\xd2\x2d\x0"\

src/htsback.c

@@ -340,12 +340,111 @@ static int back_index_ready(httrackp * opt, struct_back * sback, const char *adr
 }
 
 static int slot_can_be_cached_on_disk(const lien_back * back) {
+  /* A pending backup or spool means the slot is not finalized, and the swap
+     would unlink it through back_clear_entry() (#771). */
+  if (back->tmpfile != NULL && back->tmpfile[0] != '\0')
+    return 0;
   return (back->status == STATUS_READY && back->locked == 0
           && back->url_sav[0] != '\0'
           && strcmp(back->url_sav, BACK_ADD_TEST) != 0);
   /* Note: not checking !IS_DELAYED_EXT(back->url_sav) or it will quickly cause the slots to be filled! */
 }
 
+int back_selftest_slot_swap(void) {
+  lien_back back;
+  int err = 0;
+
+#define CHECK(want, why)                                                       \
+  do {                                                                         \
+    if (slot_can_be_cached_on_disk(&back) != (want)) {                         \
+      fprintf(stderr, "backswap: expected %d for %s\n", (want), (why));        \
+      err = 1;                                                                 \
+    }                                                                          \
+  } while (0)
+
+  memset(&back, 0, sizeof(back));
+  back.status = STATUS_READY;
+  strcpybuff(back.url_sav, "/tmp/httrack-selftest.bin");
+  CHECK(1, "a plain ready slot");
+
+  back.tmpfile = back.tmpfile_buffer;
+  strcpybuff(back.tmpfile_buffer, "/tmp/httrack-selftest.bin.bak");
+  CHECK(0, "a slot still holding a re-fetch backup");
+
+  /* Callers clear a spent temporary by emptying the name, not the pointer. */
+  back.tmpfile_buffer[0] = '\0';
+  CHECK(1, "a slot whose temporary was already dropped");
+
+  back.tmpfile = NULL;
+  back.locked = 1;
+  CHECK(0, "a locked slot");
+  back.locked = 0;
+
+  back.status = STATUS_TRANSFER;
+  CHECK(0, "a slot still transferring");
+  back.status = STATUS_READY;
+
+  back.url_sav[0] = '\0';
+  CHECK(0, "a slot with no save name");
+
+  strcpybuff(back.url_sav, BACK_ADD_TEST);
+  CHECK(0, "the dummy test slot");
+#undef CHECK
+
+  /* The swap round-trip must not lose the size of a slot whose body is already
+     at url_sav, or the link writer blanks the file (#797). */
+  {
+    static const char body[] = "swapped body";
+    int c;
+
+    for (c = 0; c < 2; c++) {
+      const hts_boolean inmemory = c == 0 ? HTS_TRUE : HTS_FALSE;
+      FILE *const fp = tmpfile();
+      lien_back *copy = NULL;
+
+      memset(&back, 0, sizeof(back));
+      back.status = STATUS_READY;
+      strcpybuff(back.url_sav, "/tmp/httrack-selftest.bin");
+      back.r.size = (LLint) sizeof(body) - 1;
+      if (inmemory) {
+        back.r.adr = strdupt(body);
+      }
+      if (fp == NULL || back_serialize(fp, &back) != 0 ||
+          fseek(fp, 0, SEEK_SET) != 0 || back_unserialize(fp, &copy) != 0) {
+        fprintf(stderr, "backswap: round-trip failed for a %s slot\n",
+                inmemory ? "buffered" : "direct-to-disk");
+        err = 1;
+      } else {
+        if (copy->r.size != back.r.size) {
+          fprintf(stderr,
+                  "backswap: %s slot came back with size " LLintP
+                  ", expected " LLintP "\n",
+                  inmemory ? "buffered" : "direct-to-disk", copy->r.size,
+                  back.r.size);
+          err = 1;
+        }
+        if (inmemory && (copy->r.adr == NULL ||
+                         memcmp(copy->r.adr, body, sizeof(body) - 1) != 0)) {
+          fprintf(stderr, "backswap: buffered slot lost its body\n");
+          err = 1;
+        }
+        if (!inmemory && copy->r.adr != NULL) {
+          fprintf(stderr, "backswap: direct-to-disk slot gained a body\n");
+          err = 1;
+        }
+        back_clear_entry(copy);
+        freet(copy);
+      }
+      if (fp != NULL)
+        fclose(fp);
+      freet(back.r.adr);
+    }
+  }
+
+  printf("backswap self-test: %s\n", err ? "FAIL" : "OK");
+  return err;
+}
+
 /* Put all backing entries that are ready in the storage hashtable to spare space and CPU */
 int back_cleanup_background(httrackp * opt, cache_back * cache,
                             struct_back * sback) {
@@ -585,6 +684,29 @@ static int create_back_tmpfile(httrackp *opt, lien_back *const back,
   return 0;
 }
 
+/* Note: utf-8 */
+void back_refetch_backup(httrackp *opt, lien_back *const back) {
+  back->tmpfile = NULL;
+  if (fexist_utf8(back->url_sav)) {
+    hts_boolean saved = HTS_FALSE;
+
+    if (create_back_tmpfile(opt, back, "bak") == 0) {
+      /* clobber a .bak a killed run left behind, or the guard stays off for
+         good (#758) */
+      if (fexist_utf8(back->tmpfile))
+        hts_log_print(opt, LOG_WARNING, "replacing leftover backup %s",
+                      back->tmpfile);
+      saved = hts_rename_over(opt, back->url_sav, back->tmpfile);
+    }
+    if (!saved) {
+      hts_log_print(opt, LOG_WARNING | LOG_ERRNO,
+                    "could not back up %s; an aborted re-fetch will lose it",
+                    back->url_sav);
+      back->tmpfile = NULL;
+    }
+  }
+}
+
 /* Did the fetch fail to produce a response, as opposed to the engine
    deliberately passing the resource over? Only the latter may be purged. */
 static hts_boolean back_transfer_failed(const int statuscode) {
@@ -615,7 +737,7 @@ static void back_finalize_backup(httrackp *opt, lien_back *const back,
     }
     /* On failure keep the backup: an orphaned temp beats losing the good copy.
      */
-    if (!hts_rename_over(back->tmpfile, back->url_sav))
+    if (!hts_rename_over(opt, back->tmpfile, back->url_sav))
       hts_log_print(opt, LOG_WARNING | LOG_ERRNO,
                     "could not restore %s; previous copy kept as %s",
                     back->url_sav, back->tmpfile);
@@ -746,7 +868,7 @@ int back_finalize(httrackp * opt, cache_back * cache, struct_back * sback,
                                  "Read error when decompressing");
                     }
                     UNLINK(unpacked);
-                  } else if (hts_rename_over(unpacked, back[p].url_sav)) {
+                  } else if (hts_rename_over(opt, unpacked, back[p].url_sav)) {
                     /* The temp bypassed filecreate(), which is what chmods. */
 #ifndef _WIN32
                     chmod(back[p].url_sav, HTS_ACCESS_FILE);
@@ -1101,6 +1223,13 @@ void back_connxfr(htsblk * src, htsblk * dst) {
   src->debugid = 0;
 }
 
+/* Release the buffers a response owns. The connection members are left alone:
+   back_connxfr() moves those, and the file handles are closed elsewhere. */
+static void back_free_response(htsblk *r) {
+  deleteaddr(r);
+  warc_free_request(r);
+}
+
 void back_move(lien_back * src, lien_back * dst) {
   memcpy(dst, src, sizeof(lien_back));
   memset(src, 0, sizeof(lien_back));
@@ -1194,7 +1323,10 @@ int back_unserialize(FILE * fp, lien_back ** dst) {
     (*dst)->r.ssl_con = NULL;
 #endif
     if (back_data_unserialize(fp, (void **) &(*dst)->r.adr, &size) == 0) {
-      (*dst)->r.size = size;
+      /* A bodyless slot already wrote its bytes to url_sav (FTP, direct to
+         disk); zeroing r.size makes the writer blank that file (#797). */
+      if ((*dst)->r.adr != NULL)
+        (*dst)->r.size = size;
       (*dst)->r.headers = NULL;
       if (back_string_unserialize(fp, &(*dst)->r.headers) == 0)
         return 0;               /* ok */
@@ -1633,10 +1765,7 @@ int back_clear_entry(lien_back * back) {
       back->r.soc = INVALID_SOCKET;
     }
 
-    if (back->r.adr != NULL) {  // reste un bloc à désallouer
-      freet(back->r.adr);
-      back->r.adr = NULL;
-    }
+    back_free_response(&back->r);
     if (back->chunk_adr != NULL) {      // reste un bloc à désallouer
       freet(back->chunk_adr);
       back->chunk_adr = NULL;
@@ -1649,12 +1778,6 @@ int back_clear_entry(lien_back * back) {
       (void) unlink(back->tmpfile);
       back->tmpfile = NULL;
     }
-    // headers
-    if (back->r.headers != NULL) {
-      freet(back->r.headers);
-      back->r.headers = NULL;
-    }
-    warc_free_request(&back->r);
     // Tout nettoyer
     memset(back, 0, sizeof(lien_back));
     back->r.soc = INVALID_SOCKET;
@@ -3164,36 +3287,7 @@ void back_wait(struct_back * sback, httrackp * opt, cache_back * cache,
                                           back[i].url_sav, 1, 1,
                                           back[i].r.notmodified);
                               back[i].r.compressed = 0;
-                              /* Re-fetch over an existing file (#77 follow-up):
-                                 move the good copy aside before truncating it
-                                 so an aborted transfer can restore it. url_sav
-                                 is still written normally (file list intact).
-                               */
-                              back[i].tmpfile = NULL;
-                              if (fexist_utf8(back[i].url_sav)) {
-                                hts_boolean saved = HTS_FALSE;
-
-                                if (create_back_tmpfile(opt, &back[i], "bak") ==
-                                    0) {
-                                  /* clobber a .bak a killed run left behind,
-                                     or the guard stays off for good (#758) */
-                                  if (fexist_utf8(back[i].tmpfile))
-                                    hts_log_print(
-                                        opt, LOG_WARNING,
-                                        "replacing leftover backup %s",
-                                        back[i].tmpfile);
-                                  saved = hts_rename_over(back[i].url_sav,
-                                                          back[i].tmpfile);
-                                }
-                                if (!saved) {
-                                  hts_log_print(
-                                      opt, LOG_WARNING | LOG_ERRNO,
-                                      "could not back up %s; an aborted "
-                                      "re-fetch will lose it",
-                                      back[i].url_sav);
-                                  back[i].tmpfile = NULL;
-                                }
-                              }
+                              back_refetch_backup(opt, &back[i]);
                               if ((back[i].r.out =
                                    filecreate(&opt->state.strc,
                                               back[i].url_sav)) == NULL) {
@@ -3988,6 +4082,9 @@ void back_wait(struct_back * sback, httrackp * opt, cache_back * cache,
 
                       memset(&tmp, 0, sizeof(tmp));
                       back_connxfr(&back[i].r, &tmp);
+                      /* the cache entry overwrites the whole struct, so drop
+                         what the 304 response still owns first (#782) */
+                      back_free_response(&back[i].r);
                       back[i].r =
                         cache_read(opt, cache, back[i].url_adr, back[i].url_fil,
                                    back[i].url_sav, back[i].location_buffer);

src/htsback.h

@@ -139,6 +139,12 @@ int back_trylive(httrackp * opt, cache_back * cache, struct_back * sback,
                  const int p);
 int back_finalize(httrackp * opt, cache_back * cache, struct_back * sback,
                   const int p);
+/* Move the previous copy of back->url_sav to back->tmpfile so back_finalize()
+   can put it back when the re-fetch fails (#77 follow-up). Call right before
+   truncating url_sav; tmpfile stays NULL when there is nothing to save. */
+void back_refetch_backup(httrackp *opt, lien_back *const back);
+/* -#test=backswap: slots eligible for the on-disk ready table. */
+int back_selftest_slot_swap(void);
 void back_info(struct_back * sback, int i, int j, FILE * fp);
 void back_infostr(struct_back *sback, int i, int j, char *s, size_t size);
 LLint back_transferred(LLint add, struct_back * sback);

src/htscache.c

@@ -985,6 +985,7 @@ void cache_init(cache_back * cache, httrackp * opt) {
               StringBuff(opt->path_log),
               "hts-cache/new.zip")))) { // a previous cache exists.. rename it
         if (!hts_rename_over(
+                opt,
                 fconcat(OPT_GET_BUFF(opt), OPT_GET_BUFF_SIZE(opt),
                         StringBuff(opt->path_log), "hts-cache/new.zip"),
                 fconcat(OPT_GET_BUFF(opt), OPT_GET_BUFF_SIZE(opt),

src/htscache_selftest.c

@@ -676,7 +676,7 @@ int cache_selftests(httrackp *opt, const char *dir) {
     char base[HTS_URLMAXSIZE];
 
     strcpybuff(base, dir);
-    if (base[0] != '\0' && base[strlen(base) - 1] != '/') {
+    if (base[0] != '\0' && hts_lastchar(base) != '/') {
       strcatbuff(base, "/");
     }
     StringCopy(opt->path_log, base);
@@ -856,7 +856,7 @@ static void golden_setup(httrackp *opt, const char *dir) {
   char base[HTS_URLMAXSIZE];
 
   strcpybuff(base, dir);
-  if (base[0] != '\0' && base[strlen(base) - 1] != '/') {
+  if (base[0] != '\0' && hts_lastchar(base) != '/') {
     strcatbuff(base, "/");
   }
   StringCopy(opt->path_log, base);

src/htscore.c

@@ -773,7 +773,7 @@ int httpmirror(char *url1, httrackp * opt) {
         // sauter les + sans rien après..
         if (strnotempty(tempo)) {
           if ((plus == 0) && (type == 1)) {     // implicite: *www.edf.fr par exemple
-            if (tempo[strlen(tempo) - 1] != '*') {
+            if (hts_lastchar(tempo) != '*') {
               strcatbuff(tempo, "*");   // ajouter un *
             }
           }
@@ -1819,60 +1819,6 @@ int httpmirror(char *url1, httrackp * opt) {
         // -- -- --
         // sauver fichier
 
-        /* En cas d'erreur, vérifier que fichier d'erreur existe */
-        if (strnotempty(savename()) == 0) {       // chemin de sauvegarde existant
-          if (strcmp(urlfil(), "/robots.txt") == 0) {     // pas robots.txt
-            if (store_errpage) {        // c'est une page d'erreur
-              int create_html_warning = 0;
-              int create_gif_warning = 0;
-
-              switch (ishtml(opt, urlfil())) {    /* pas fichier html */
-              case 0:          /* non html */
-                {
-                  char buff[256];
-
-                  guess_httptype_sized(opt, buff, sizeof(buff), urlfil());
-                  if (strcmp(buff, "image/gif") == 0)
-                    create_gif_warning = 1;
-                }
-                break;
-              case 1:          /* html */
-                if (!r.adr) {
-                }
-                break;
-              default:         /* don't know.. */
-                break;
-              }
-              /* Créer message d'erreur ? */
-              if (create_html_warning) {
-                char *adr =
-                  (char *) malloct(strlen(HTS_DATA_ERROR_HTML) + 1100);
-                hts_log_print(opt, LOG_INFO, "Creating HTML warning file (%s)",
-                              r.msg);
-                if (adr) {
-                  if (r.adr) {
-                    freet(r.adr);
-                    r.adr = NULL;
-                  }
-                  sprintf(adr, HTS_DATA_ERROR_HTML, r.msg);
-                  r.adr = adr;
-                }
-              } else if (create_gif_warning) {
-                char *adr = (char *) malloct(HTS_DATA_UNKNOWN_GIF_LEN);
-
-                hts_log_print(opt, LOG_INFO, "Creating GIF dummy file (%s)",
-                              r.msg);
-                if (r.adr) {
-                  freet(r.adr);
-                  r.adr = NULL;
-                }
-                memcpy(adr, HTS_DATA_UNKNOWN_GIF, HTS_DATA_UNKNOWN_GIF_LEN);
-                r.adr = adr;
-              }
-            }
-          }
-        }
-
         if (strnotempty(savename()) == 0) {       // pas de chemin de sauvegarde
           if (strcmp(urlfil(), "/robots.txt") == 0) {     // robots.txt
             char BIGSTK sitemaps[8192];
@@ -2190,7 +2136,9 @@ int httpmirror(char *url1, httrackp * opt) {
                   continue;
                 strcpybuff(file, StringBuff(opt->path_html));
                 strcatbuff(file, line + 1);
-                file[strlen(file) - 1] = '\0';
+                /* strip filenote()'s ']', absent when linput() truncated the
+                   line */
+                hts_striplastchar(file, ']');
                 hts_changes_previous(opt, file + StringLength(opt->path_html));
                 if (!strstr(adr, line)) { // not found in the new list?
                   if (fexist_utf8(file)) { // still on disk
@@ -2217,12 +2165,11 @@ int httpmirror(char *url1, httrackp * opt) {
                 fseek(old_lst, 0, SEEK_SET);
                 while(!feof(old_lst)) {
                   linput(old_lst, line, 1000);
-                  while(strnotempty(line) && (line[strlen(line) - 1] != '/')
-                        && (line[strlen(line) - 1] != '\\')) {
-                    line[strlen(line) - 1] = '\0';
+                  while (strnotempty(line) && (hts_lastchar(line) != '/') &&
+                         (hts_lastchar(line) != '\\')) {
+                    hts_choplastchar(line);
                   }
-                  if (strnotempty(line))
-                    line[strlen(line) - 1] = '\0';
+                  hts_choplastchar(line);
                   if (strnotempty(line))
                     if (!strstr(adr, line)) {   // non trouvé?
                       char BIGSTK file[HTS_URLMAXSIZE * 2];
@@ -2235,13 +2182,12 @@ int httpmirror(char *url1, httrackp * opt) {
                         if (opt->log) {
                           hts_log_print(opt, LOG_INFO, "Purging directory %s/",
                                         file);
-                          while(strnotempty(file)
-                                && (file[strlen(file) - 1] != '/')
-                                && (file[strlen(file) - 1] != '\\')) {
-                            file[strlen(file) - 1] = '\0';
+                          while (strnotempty(file) &&
+                                 (hts_lastchar(file) != '/') &&
+                                 (hts_lastchar(file) != '\\')) {
+                            hts_choplastchar(file);
                           }
-                          if (strnotempty(file))
-                            file[strlen(file) - 1] = '\0';
+                          hts_choplastchar(file);
                         }
                       }
                     }

src/htscoremain.c

@@ -357,7 +357,7 @@ static int hts_main_internal(int argc, char **argv, httrackp * opt) {
           char BIGSTK tempo[HTS_CDLMAXSIZE];
 
           strcpybuff(tempo, argv[na] + 1);
-          if (tempo[0] == '\0' || tempo[strlen(tempo) - 1] != '"') {
+          if (hts_lastchar(tempo) != '"') {
             char BIGSTK s[HTS_CDLMAXSIZE];
 
             sprintf(s, "Missing quote in %s", argv[na]);
@@ -365,7 +365,7 @@ static int hts_main_internal(int argc, char **argv, httrackp * opt) {
             htsmain_free();
             return -1;
           }
-          tempo[strlen(tempo) - 1] = '\0';
+          hts_choplastchar(tempo);
           /* tempo is argv[na] minus its surrounding quotes, so it fits in place
            */
           strlcpybuff(argv[na], tempo, strlen(argv[na]) + 1);
@@ -863,7 +863,7 @@ static int hts_main_internal(int argc, char **argv, httrackp * opt) {
         char BIGSTK tempo[HTS_CDLMAXSIZE + 256];
 
         strcpybuff(tempo, argv[na] + 1);
-        if (tempo[0] == '\0' || tempo[strlen(tempo) - 1] != '"') {
+        if (hts_lastchar(tempo) != '"') {
           char s[HTS_CDLMAXSIZE + 256];
 
           sprintf(s, "Missing quote in %s", argv[na]);
@@ -871,7 +871,7 @@ static int hts_main_internal(int argc, char **argv, httrackp * opt) {
           htsmain_free();
           return -1;
         }
-        tempo[strlen(tempo) - 1] = '\0';
+        hts_choplastchar(tempo);
         /* tempo is argv[na] minus its surrounding quotes, so it fits in place
          */
         strlcpybuff(argv[na], tempo, strlen(argv[na]) + 1);
@@ -2724,10 +2724,7 @@ static int hts_main_internal(int argc, char **argv, httrackp * opt) {
       char *a;
 
       strcpybuff(rpath, StringBuff(opt->path_html));
-      if (rpath[0]) {
-        if (rpath[strlen(rpath) - 1] == '/')
-          rpath[strlen(rpath) - 1] = '\0';
-      }
+      hts_striplastchar(rpath, '/');
       a = strrchr(rpath, '/');
       if (a) {
         *a = '\0';

src/htsftp.c

@@ -483,16 +483,19 @@ int run_launch_ftp(FTPDownloadStruct * pStruct) {
                     back->r.totalsize = size;
                   }
                 }
-                // REST?
-                if (fexist(back->url_sav) && (transfer_list == 0)) {
+                /* Only over a copy back_add() judged partial: on --update every
+                   mirrored file exists, and resuming a complete one splices the
+                   old body into the new (#798). */
+                if (back->range_req_size > 0 && (transfer_list == 0)) {
                   strcpybuff(back->info, "rest");
-                  snprintf(line, sizeof(line), "REST " LLintP, (LLint) fsize(back->url_sav));
+                  snprintf(line, sizeof(line), "REST " LLintP,
+                           (LLint) back->range_req_size);
                   send_line(soc_ctl, line);
                   get_ftp_line(soc_ctl, line, sizeof(line), timeout);
                   _CHECK_HALT_FTP;
                   if ((line[0] == '3') || (line[0] == '2')) {   // ok
                     rest_understood = 1;
-                  }             // sinon tant pis 
+                  } // else never mind
                 }
               }                 // sinon tant pis 
             }
@@ -617,13 +620,19 @@ int run_launch_ftp(FTPDownloadStruct * pStruct) {
         // Ok, connexion initiée
         //
         if (soc_dat != INVALID_SOCKET) {
-          if (rest_understood) {        // REST envoyée et comprise
+          if (rest_understood) { // REST sent and understood
             file_notify(opt, back->url_adr, back->url_fil, back->url_sav, 0, 1,
                         0);
+            /* The bytes already on disk count too, or the completeness check
+               below rejects every resumed transfer (#798). */
+            back->r.size = back->range_req_size;
             back->r.fp = fileappend(&opt->state.strc, back->url_sav);
           } else {
             file_notify(opt, back->url_adr, back->url_fil, back->url_sav, 1, 1,
                         0);
+            /* Every failure exit below would else leave the mirror truncated
+               (#771); the resume branch appends and needs no backup. */
+            back_refetch_backup(opt, back);
             back->r.fp = filecreate(&opt->state.strc, back->url_sav);
           }
           strcpybuff(back->info, "receiving");

src/htshelp.c

@@ -83,9 +83,8 @@ void infomsg(const char *msg) {
               /* try the flag as-is, then strip a trailing N as the numeric-arg
                  placeholder (cN -> c); this order keeps -%N from becoming -% */
               p = optreal_find(cmd);
-              if (p < 0 && (int) strlen(cmd) > 2 &&
-                  cmd[strlen(cmd) - 1] == 'N') {
-                cmd[strlen(cmd) - 1] = '\0';
+              if (p < 0 && (int) strlen(cmd) > 2 && hts_lastchar(cmd) == 'N') {
+                hts_striplastchar(cmd, 'N');
                 p = optreal_find(cmd);
               }
               if (p >= 0) {
@@ -211,7 +210,7 @@ void help_wizard(httrackp * opt) {
     strcatbuff(str, "/websites/");
   }
   if (strnotempty(str))
-    if ((str[strlen(str) - 1] != '/') && (str[strlen(str) - 1] != '\\'))
+    if ((hts_lastchar(str) != '/') && (hts_lastchar(str) != '\\'))
       strcatbuff(str, "/");
   strcatbuff(stropt2, "-O \"");
   strcatbuff(stropt2, str);
@@ -559,8 +558,7 @@ void help(const char *app, int more) {
   infomsg
     (" %q *include query string for local files (useless, for information purpose only) (%q0 don't include)");
   infomsg(" %g  strip query keys for dedup ([host/pattern=]key1,key2,...)");
-  infomsg
-    ("  o *generate output html file in case of error (404..) (o0 don't generate)");
+  infomsg("  o *save the server's error pages (404..) (o0 discard them)");
   infomsg("  X *purge old files after update (X0 keep delete)");
   infomsg(" %p  preserve html files 'as is' (identical to '-K4 -%F \"\"')");
   infomsg(" %T  links conversion to UTF-8");

src/htslib.c

@@ -2703,17 +2703,8 @@ void hts_now_iso8601(char out[32]) {
   time_t t = time(NULL);
   struct tm tmv;
 
-#if defined(_WIN32)
-  struct tm *g = gmtime(&t);
-
-  if (g != NULL)
-    tmv = *g;
-  else
+  if (!hts_gmtime(t, &tmv))
     memset(&tmv, 0, sizeof(tmv));
-#else
-  if (gmtime_r(&t, &tmv) == NULL)
-    memset(&tmv, 0, sizeof(tmv));
-#endif
   strftime(out, 32, "%Y-%m-%dT%H:%M:%SZ", &tmv);
 }
 
@@ -5078,7 +5069,7 @@ static int hts_dns_resolve_nocache_list(const char *const hostname,
   if (!strnotempty(hostname) || max <= 0) {
     return 0;
   }
-  if ((hostname[0] == '[') && (hostname[strlen(hostname) - 1] == ']')) {
+  if ((hostname[0] == '[') && (hts_lastchar(hostname) == ']')) {
     size_t size = strlen(hostname);
     char *copy = malloct(size + 1);
     int count;
@@ -5491,9 +5482,8 @@ void cut_path(char *fullpath, char *path, size_t path_size, char *pname,
               size_t pname_size) {
   path[0] = pname[0] = '\0';
   if (strnotempty(fullpath)) {
-    if ((fullpath[strlen(fullpath) - 1] == '/')
-        || (fullpath[strlen(fullpath) - 1] == '\\'))
-      fullpath[strlen(fullpath) - 1] = '\0';
+    if (!hts_striplastchar(fullpath, '/'))
+      hts_striplastchar(fullpath, '\\');
     if (strlen(fullpath) > 1) {
       char *a;
 
@@ -5791,7 +5781,8 @@ HTSEXT_API void hts_log_vprint(httrackp * opt, int type, const char *format, va_
   if (hts_log_print_callback != NULL) {
     va_list args_copy;
     va_copy(args_copy, args);
-    hts_log_print_callback(opt, type, format, args);
+    /* the copy, so the vfprintf() below still has an unread list */
+    hts_log_print_callback(opt, type, format, args_copy);
     va_end(args_copy);
   }
   if (opt != NULL && opt->log != NULL) {
@@ -6648,9 +6639,12 @@ int hts_rename_utf8(const char *oldpath, const char *newpath) {
   LPWSTR wnewpath = hts_pathToUCS2(newpath);
   if (woldpath != NULL && wnewpath != NULL) {
     const int result = _wrename(woldpath, wnewpath);
+    /* Save errno: callers key off it (#779) and free() may clobber it. */
+    const int err = errno;
 
     free(woldpath);
     free(wnewpath);
+    errno = err;
     return result;
   } else {
     if (woldpath != NULL)

src/htslib.h

@@ -157,6 +157,19 @@ struct t_dnscache {
   char host_addr[HTS_MAXADDRNUM][HTS_MAXADDRLEN];
 };
 
+/* Break t down as UTC into the caller's buffer, HTS_FALSE if that failed.
+   gmtime()'s static is shared, and both the engine and ProxyTrack convert on
+   worker threads. */
+static HTS_INLINE HTS_UNUSED hts_boolean hts_gmtime(time_t t,
+                                                    struct tm *tmbuf) {
+#ifdef _WIN32
+  /* Microsoft's gmtime_s takes the destination first, unlike C11 Annex K. */
+  return gmtime_s(tmbuf, &t) == 0 ? HTS_TRUE : HTS_FALSE;
+#else
+  return gmtime_r(&t, tmbuf) != NULL ? HTS_TRUE : HTS_FALSE;
+#endif
+}
+
 /* Library internal definictions */
 #ifdef HTS_INTERNAL_BYTECODE
 

src/htsname.c

@@ -437,9 +437,7 @@ int url_savename(lien_adrfilsave *const afs,
 
       strcpybuff(fil_complete_patche, normfil);
       // Version avec ou sans /
-      if (fil_complete_patche[strlen(fil_complete_patche) - 1] == '/')
-        fil_complete_patche[strlen(fil_complete_patche) - 1] = '\0';
-      else
+      if (!hts_striplastchar(fil_complete_patche, '/'))
         strcatbuff(fil_complete_patche, "/");
       i = hash_read(hash, normadr, fil_complete_patche, HASH_STRUCT_ORIGINAL_ADR_PATH);       // recherche table 2 (former->adr+former->fil)
       if (i >= 0) {
@@ -515,7 +513,8 @@ int url_savename(lien_adrfilsave *const afs,
         && protocol != PROTOCOL_FTP
       ) {
       // tester type avec requète HEAD si on ne connait pas le type du fichier
-      if (!((opt->check_type == 1) && (fil[strlen(fil) - 1] == '/')))   // slash doit être html?
+      if (!((opt->check_type == 1) &&
+            (hts_lastchar(fil) == '/'))) // slash doit être html?
         if (opt->savename_delayed == HTS_SAVENAME_DELAYED_HARD ||
             ishtml(opt, fil) < 0) { // unsure whether it's html or a file
           // lire dans le cache
@@ -810,7 +809,7 @@ int url_savename(lien_adrfilsave *const afs,
   // - - - DEBUT NOMMAGE - - -
 
   // Donner nom par défaut?
-  if (fil[strlen(fil) - 1] == '/') {
+  if (hts_lastchar(fil) == '/') {
     if (!strfield(adr_complete, "ftp://")
       ) {
       strcatbuff(fil, DEFAULT_HTML);    // nommer page par défaut!!
@@ -1284,7 +1283,7 @@ int url_savename(lien_adrfilsave *const afs,
 
     hts_lowcase(afs->save);
 
-    if (afs->save[strlen(afs->save) - 1] == '/')
+    if (hts_lastchar(afs->save) == '/')
       strcatbuff(afs->save, DEFAULT_HTML);   // nommer page par défaut!!
   }
 

src/htsparse.c

@@ -1701,7 +1701,8 @@ int htsparse(htsmoduleStruct * str, htsmoduleStructExtended * stre) {
 #endif
                                     )   // ok pas de problème
                                     url_ok = 1;
-                                  else if (tempo[strlen(tempo) - 1] == '/') {   // un slash: ok..
+                                  else if (hts_lastchar(tempo) ==
+                                           '/') {       // un slash: ok..
                                     if (inscript)       // sinon si pas javascript, méfiance (répertoire style base?)
                                       url_ok = 1;
                                   }
@@ -2005,9 +2006,8 @@ int htsparse(htsmoduleStruct * str, htsmoduleStructExtended * stre) {
               if (eadr - html - 1 < HTS_URLMAXSIZE) {        // pas trop long?
                 strncpy(lien, html, eadr - html - 1);
                 lien[eadr - html - 1] = '\0';
-                // supprimer les espaces
-                while((lien[strlen(lien) - 1] == ' ') && (strnotempty(lien)))
-                  lien[strlen(lien) - 1] = '\0';
+                while (hts_striplastchar(lien, ' ')) {
+                }
 
               } else
                 lien[0] = '\0'; // erreur
@@ -2207,7 +2207,7 @@ int htsparse(htsmoduleStruct * str, htsmoduleStructExtended * stre) {
                 // supposition dangereuse?
                 // OUI!!
 #if HTS_TILDE_SLASH
-                if (lien[strlen(lien) - 1] != '/') {
+                if (hts_lastchar(lien) != '/') {
                   char *a = lien + strlen(lien) - 1;
 
                   // éviter aussi index~1.html
@@ -2272,7 +2272,7 @@ int htsparse(htsmoduleStruct * str, htsmoduleStructExtended * stre) {
                     // Vérifier les codebase=applet (au lieu de applet/)
                     if (p_type == -2) { // codebase
                       if (strnotempty(lien)) {
-                        if (lien[strlen(lien) - 1] != '/') {     // pas répertoire
+                        if (hts_lastchar(lien) != '/') { // pas répertoire
                           strcatbuff(lien, "/");
                         }
                       }
@@ -2688,9 +2688,11 @@ int htsparse(htsmoduleStruct * str, htsmoduleStructExtended * stre) {
                             int cat_data_len = 0;
 
                             // ajouter lien external
-                            switch ((link_has_authority(afs.af.adr)) ? 1
-                                    : ((afs.af.fil[strlen(afs.af.fil) - 1] ==
-                                        '/') ? 1 : (ishtml(opt, afs.af.fil)))) {
+                            switch ((link_has_authority(afs.af.adr))
+                                        ? 1
+                                        : ((hts_lastchar(afs.af.fil) == '/')
+                                               ? 1
+                                               : (ishtml(opt, afs.af.fil)))) {
                             case 1:
                             case -2:   // html ou répertoire
                               if (opt->getmode & HTS_GETMODE_HTML) {
@@ -2733,7 +2735,7 @@ int htsparse(htsmoduleStruct * str, htsmoduleStructExtended * stre) {
                                 cat_data_len = HTS_DATA_UNKNOWN_HTML_LEN;
                               }
                               break;
-                            }   // html,gif
+                            } // html,gif
 
                             if (patch_it) {
                               char BIGSTK save[HTS_URLMAXSIZE * 2];

src/htssafe.h

@@ -539,6 +539,36 @@ static HTS_INLINE HTS_UNUSED HTS_PRINTF_FUN(3, 4) void slprintfbuff_clip(
 #define sprintfbuff(ARR, ...) slprintfbuff((ARR), sizeof(ARR), __VA_ARGS__)
 #endif
 
+/* Last character of s, or '\0' when s is empty. Replaces s[strlen(s) - 1],
+   which indexes one byte before the buffer on an empty string. */
+static HTS_INLINE HTS_UNUSED char hts_lastchar(const char *s) {
+  const size_t len = strlen(s);
+
+  return len != 0 ? s[len - 1] : '\0';
+}
+
+/* Drop a trailing c from s if present; HTS_TRUE if one was dropped. */
+static HTS_INLINE HTS_UNUSED hts_boolean hts_striplastchar(char *s, char c) {
+  const size_t len = strlen(s);
+
+  if (len != 0 && s[len - 1] == c) {
+    s[len - 1] = '\0';
+    return HTS_TRUE;
+  }
+  return HTS_FALSE;
+}
+
+/* Drop the last character of s whatever it is; HTS_TRUE if s was not empty. */
+static HTS_INLINE HTS_UNUSED hts_boolean hts_choplastchar(char *s) {
+  const size_t len = strlen(s);
+
+  if (len != 0) {
+    s[len - 1] = '\0';
+    return HTS_TRUE;
+  }
+  return HTS_FALSE;
+}
+
 /* Thin aliases over the libc allocator/memcpy (historical "t" suffix); no
    added bounds checking. freet() also NULLs the freed pointer and tolerates
    NULL. memcpybuff() despite the name is a raw memcpy: the caller owns the

src/htsselftest.c

@@ -2622,6 +2622,74 @@ static int st_savename(httrackp *opt, int argc, char **argv) {
   return 0;
 }
 
+static char st_log_callback_seen[256];
+
+static void st_log_callback(httrackp *opt, int type, const char *format,
+                            va_list args) {
+  (void) opt;
+  (void) type;
+  (void) vsnprintf(st_log_callback_seen, sizeof(st_log_callback_seen), format,
+                   args);
+}
+
+/* The callback must not consume the va_list the log file's vfprintf() needs. */
+static int st_logcallback(httrackp *opt, int argc, char **argv) {
+  static const char want[] = "42 sentinel";
+  static const char want_filtered[] = "7 filtered";
+  char BIGSTK seen[sizeof(st_log_callback_seen)];
+  char BIGSTK line[256];
+  FILE *fp;
+  int rc = 1;
+
+  (void) argc;
+  (void) argv;
+
+  fp = tmpfile();
+  if (fp == NULL) {
+    fprintf(stderr, "logcallback: tmpfile() failed\n");
+    return 1;
+  }
+  opt->log = fp;
+  opt->debug = LOG_NOTICE;
+  st_log_callback_seen[0] = '\0';
+  hts_set_log_vprint_callback(st_log_callback);
+  hts_log_print(opt, LOG_NOTICE, "%d %s", 42, "sentinel");
+  hts_set_log_vprint_callback(NULL);
+  opt->log = NULL;
+  strcpybuff(seen, st_log_callback_seen);
+
+  rewind(fp);
+  if (fgets(line, (int) sizeof(line), fp) == NULL) {
+    fprintf(stderr, "logcallback: log file is empty, nothing was written\n");
+    fclose(fp);
+    return 1;
+  }
+  fclose(fp);
+
+  /* The callback runs above the level filter and without a log file at all;
+     the front-ends that install one usually have no opt->log open. */
+  st_log_callback_seen[0] = '\0';
+  hts_set_log_vprint_callback(st_log_callback);
+  hts_log_print(opt, LOG_DEBUG, "%d %s", 7, "filtered");
+  hts_set_log_vprint_callback(NULL);
+
+  /* Same arguments both ways; the file line carries a level prefix. */
+  if (strcmp(seen, want) != 0)
+    fprintf(stderr, "logcallback: callback got '%s' want '%s'\n", seen, want);
+  else if (strstr(line, want) == NULL)
+    fprintf(stderr, "logcallback: log file got '%s' want it to carry '%s'\n",
+            line, want);
+  else if (strcmp(st_log_callback_seen, want_filtered) != 0)
+    fprintf(stderr, "logcallback: unfiltered callback got '%s' want '%s'\n",
+            st_log_callback_seen, want_filtered);
+  else
+    rc = 0;
+
+  if (rc == 0)
+    printf("logcallback self-test OK\n");
+  return rc;
+}
+
 /* an empty fil started htsAddLink's codebase walk before the buffer (#730) */
 static int st_addlink(httrackp *opt, int argc, char **argv) {
   htsmoduleStruct BIGSTK str;
@@ -4944,6 +5012,101 @@ static int st_warc_surt(httrackp *opt, int argc, char **argv) {
   return err;
 }
 
+/* A URL longer than the old 1024-byte header-format buffer must still reach the
+   archive: the record used to be abandoned whole, silently (#785). The sweep
+   straddles the boundary so both the stack-buffer and the grow path run. */
+static int st_warc_longurl(httrackp *opt, int argc, char **argv) {
+  /* "WARC-Target-URI: " + CRLF costs 19 bytes, so the old buffer failed at
+     1005; 9000 forces several reallocs within one record. */
+  static const size_t lengths[] = {100, 1003, 1004, 1005, 1006, 2000, 9000};
+  static const char resp_hdr[] =
+      "HTTP/1.1 200 OK\r\nContent-Type: text/html\r\n\r\n";
+  char path[HTS_URLMAXSIZE * 2];
+  char body[64];
+  warc_writer *w;
+  FILE *fp;
+  char *blob;
+  LLint fsz;
+  const char *at2;
+  size_t i, n, nrec = 0;
+  int err = 0;
+
+  if (argc < 1) {
+    fprintf(stderr, "warc-longurl: need a writable directory\n");
+    return 1;
+  }
+  snprintf(path, sizeof(path), "%s/longurl.warc", argv[0]);
+
+  w = warc_open(opt, path);
+  if (w == NULL) {
+    fprintf(stderr, "warc-longurl: could not create %s\n", path);
+    return 1;
+  }
+  for (i = 0; i < sizeof(lengths) / sizeof(lengths[0]); i++) {
+    const size_t len = lengths[i];
+    char *uri = malloct(len + 1);
+
+    if (uri == NULL) {
+      warc_close(w);
+      return 1;
+    }
+    /* A distinct tail per URI so a truncated one cannot match another. */
+    snprintf(uri, len + 1, "http://example.com/%04d/", (int) len);
+    memset(uri + strlen(uri), 'a', len - strlen(uri));
+    uri[len] = '\0';
+    /* Distinct payloads: identical ones dedupe into revisit records. */
+    snprintf(body, sizeof(body), "<html><body>%04d</body></html>\n", (int) len);
+    if (warc_write_transaction(w, uri, NULL, NULL, resp_hdr, body, strlen(body),
+                               NULL, 200, 0, 0) != 0) {
+      fprintf(stderr, "warc-longurl: write failed at length %d\n", (int) len);
+      err = 1;
+    }
+    freet(uri);
+  }
+  warc_close(w);
+
+  fsz = fsize_utf8(path);
+  blob = (fsz > 0) ? malloct((size_t) fsz + 1) : NULL;
+  if (blob == NULL) {
+    fprintf(stderr, "warc-longurl: no archive written\n");
+    return 1;
+  }
+  fp = FOPEN(path, "rb");
+  n = (fp != NULL) ? fread(blob, 1, (size_t) fsz, fp) : 0;
+  if (fp != NULL)
+    fclose(fp);
+  blob[n] = '\0';
+
+  for (i = 0; i < sizeof(lengths) / sizeof(lengths[0]); i++) {
+    const size_t len = lengths[i];
+    char want[64];
+    const char *at;
+
+    snprintf(want, sizeof(want), "WARC-Target-URI: http://example.com/%04d/",
+             (int) len);
+    at = strstr(blob, want);
+    if (at == NULL) {
+      fprintf(stderr, "warc-longurl: length %d lost its record\n", (int) len);
+      err = 1;
+    } else if (strlen(at) < strlen("WARC-Target-URI: ") + len ||
+               at[strlen("WARC-Target-URI: ") + len] != '\r') {
+      fprintf(stderr, "warc-longurl: length %d truncated\n", (int) len);
+      err = 1;
+    }
+  }
+  for (at2 = blob; (at2 = strstr(at2, "WARC-Type: response")) != NULL; at2++)
+    nrec++;
+  if (nrec != sizeof(lengths) / sizeof(lengths[0])) {
+    fprintf(stderr, "warc-longurl: %d response records, want %d\n", (int) nrec,
+            (int) (sizeof(lengths) / sizeof(lengths[0])));
+    err = 1;
+  }
+
+  freet(blob);
+  printf("warc-longurl: %s\n", err ? "FAIL" : "OK");
+  return err;
+}
+
 /* End-to-end CDXJ: crawl a handful of records with --warc-cdx, then verify the
    .cdx is sorted, has exactly one line per response/revisit/resource (none for
    warcinfo/request), and each offset/length points at a gzip member that
@@ -5955,6 +6118,206 @@ static int st_mirrorio(httrackp *opt, int argc, char **argv) {
   return 0;
 }
 
+static void ro_put(const char *path, const char *data) {
+  FILE *const fp = FOPEN(path, "wb");
+
+  assertf(fp != NULL);
+  assertf(fwrite(data, 1, strlen(data), fp) == strlen(data));
+  fclose(fp);
+}
+
+/* HTS_TRUE if path holds exactly data. */
+static hts_boolean ro_is(const char *path, const char *data) {
+  char buf[64];
+  FILE *const fp = FOPEN(path, "rb");
+  size_t n;
+
+  if (fp == NULL)
+    return HTS_FALSE;
+  n = fread(buf, 1, sizeof(buf), fp);
+  fclose(fp);
+  return n == strlen(data) && memcmp(buf, data, n) == 0 ? HTS_TRUE : HTS_FALSE;
+}
+
+// -#test=renameover <dir>: hts_rename_over() must replace an existing dst and
+// never lose one it did not replace (#779, #790). Which half is live depends on
+// what rename() does to an existing target, so probe that and name the regime.
+static int st_renameover(httrackp *opt, int argc, char **argv) {
+  if (argc < 1) {
+    fprintf(stderr, "renameover: needs a writable base dir\n");
+    return 1;
+  }
+  char src[HTS_URLMAXSIZE * 2], dst[HTS_URLMAXSIZE * 2];
+  int err = 0;
+
+  fconcat(src, sizeof(src), argv[0], "renameover-src.bin");
+  fconcat(dst, sizeof(dst), argv[0], "renameover-dst.bin");
+
+  (void) UNLINK(src);
+  (void) UNLINK(dst);
+  ro_put(src, "probe");
+  ro_put(dst, "probe");
+
+  const int probe = RENAME(src, dst) == 0 ? 0 : errno;
+  /* Only a target in the way is something the unlink can clear. */
+  const hts_boolean replaceable = probe == 0 || probe == EEXIST;
+
+  printf("renameover: regime %s\n",
+         probe == 0 ? "clobber" : (probe == EEXIST ? "fallback" : "refused"));
+
+  (void) UNLINK(src);
+  (void) UNLINK(dst);
+  ro_put(src, "new");
+  ro_put(dst, "old");
+  if (replaceable) {
+    /* An existing dst must still be replaced: the unlink is for this. */
+    if (!hts_rename_over(opt, src, dst)) {
+      fprintf(stderr, "renameover: replacing an existing dst failed: %s\n",
+              strerror(errno));
+      err++;
+    } else if (!ro_is(dst, "new") || fexist_utf8(src)) {
+      fprintf(stderr, "renameover: dst was not replaced by src\n");
+      err++;
+    }
+  } else {
+    /* A failure the unlink cannot fix must leave dst as it was. */
+    if (hts_rename_over(opt, src, dst)) {
+      fprintf(stderr, "renameover: an unfixable failure reported success\n");
+      err++;
+    }
+    if (!ro_is(dst, "old")) {
+      fprintf(stderr, "renameover: an unfixable failure destroyed dst\n");
+      err++;
+    }
+  }
+
+  /* A directory in the way is not something the caller asked to replace: it
+     must be refused, never parked aside and orphaned. */
+  (void) UNLINK(dst);
+  ro_put(src, "new");
+  if (MKDIR(dst) == 0) {
+    char parked[sizeof(dst) + 16];
+
+    snprintf(parked, sizeof(parked), "%s.hts-old0", dst);
+    if (hts_rename_over(opt, src, dst)) {
+      fprintf(stderr, "renameover: a directory at dst reported success\n");
+      err++;
+    }
+    if (!ro_is(src, "new")) {
+      fprintf(stderr, "renameover: a directory at dst consumed src\n");
+      err++;
+    }
+    /* RMDIR only succeeds on a directory that is there, so it doubles as the
+       probe: the parked name must not exist at all. */
+    if (RMDIR(parked) == 0 || fexist_utf8(parked)) {
+      fprintf(stderr, "renameover: a directory at dst was parked aside\n");
+      err++;
+    }
+    (void) RMDIR(dst);
+  }
+  (void) UNLINK(src);
+
+  /* A missing src must leave dst alone and report failure. */
+  (void) UNLINK(src);
+  ro_put(dst, "keep");
+  if (hts_rename_over(opt, src, dst)) {
+    fprintf(stderr, "renameover: a missing src reported success\n");
+    err++;
+  }
+  if (!ro_is(dst, "keep")) {
+    fprintf(stderr, "renameover: a missing src destroyed dst\n");
+    err++;
+  }
+
+  /* Same, with dst absent too: nothing to lose, still a failure. */
+  (void) UNLINK(dst);
+  if (hts_rename_over(opt, src, dst)) {
+    fprintf(stderr, "renameover: a missing src and dst reported success\n");
+    err++;
+  }
+
+  /* The aside fallback, driven directly: a clobbering rename() never reaches
+     it. Skipped in the refused regime, where no rename at all succeeds. */
+  if (replaceable) {
+    char aside[sizeof(dst) + 16], keep[sizeof(dst) + 16];
+
+    snprintf(aside, sizeof(aside), "%s.hts-old0", dst);
+    snprintf(keep, sizeof(keep), "%s.hts-old1", dst);
+    (void) UNLINK(aside);
+    (void) UNLINK(keep);
+    ro_put(src, "new");
+    ro_put(dst, "old");
+    if (!hts_rename_over_aside_selftest(opt, src, dst)) {
+      fprintf(stderr, "renameover: the aside fallback failed: %s\n",
+              strerror(errno));
+      err++;
+    } else if (!ro_is(dst, "new") || fexist_utf8(src) || fexist_utf8(aside)) {
+      fprintf(stderr, "renameover: the aside fallback did not replace dst\n");
+      err++;
+    }
+
+    /* #790: the retry fails (no src). The old content must survive, back at dst
+       or, when the move back fails too, under the parked name it is logged as.
+       Name the outcome so a leg cannot pass having tested the other one. */
+    (void) UNLINK(src);
+    ro_put(dst, "old");
+    if (hts_rename_over_aside_selftest(opt, src, dst)) {
+      fprintf(stderr, "renameover: a failed aside retry reported success\n");
+      err++;
+    }
+    if (ro_is(dst, "old") && !fexist_utf8(aside)) {
+      printf("renameover: restore back\n");
+    } else if (ro_is(aside, "old") && !fexist_utf8(dst)) {
+      printf("renameover: restore parked\n");
+      (void) UNLINK(aside);
+      ro_put(dst, "old");
+    } else {
+      fprintf(stderr, "renameover: a failed aside retry lost the old copy\n");
+      err++;
+    }
+
+    /* An unrelated file already sitting on the aside name must survive. */
+    ro_put(src, "new");
+    ro_put(aside, "mine");
+    if (!hts_rename_over_aside_selftest(opt, src, dst)) {
+      fprintf(stderr, "renameover: a taken aside name failed the move: %s\n",
+              strerror(errno));
+      err++;
+    } else if (!ro_is(dst, "new") || !ro_is(aside, "mine") ||
+               fexist_utf8(keep)) {
+      fprintf(stderr, "renameover: a taken aside name was not skipped\n");
+      err++;
+    }
+    (void) UNLINK(aside);
+    (void) UNLINK(keep);
+
+    /* A directory there reads as free to the probe, so the park must skip it
+       on the refusal rather than give up. */
+    ro_put(src, "new");
+    ro_put(dst, "old");
+    if (MKDIR(aside) == 0) {
+      if (!hts_rename_over_aside_selftest(opt, src, dst)) {
+        fprintf(stderr,
+                "renameover: a directory on the aside name blocked the "
+                "move: %s\n",
+                strerror(errno));
+        err++;
+      } else if (!ro_is(dst, "new") || fexist_utf8(keep)) {
+        fprintf(stderr, "renameover: a directory on the aside name was not "
+                        "skipped\n");
+        err++;
+      }
+      (void) RMDIR(aside);
+    }
+    (void) UNLINK(keep);
+  }
+
+  (void) UNLINK(src);
+  (void) UNLINK(dst);
+  printf("renameover: %s\n", err ? "FAIL" : "OK");
+  return err;
+}
+
 // -#test=direnum <dir>: enumerate a long+non-ASCII directory via the
 // opendir/readdir wrappers; children must round-trip as UTF-8 (#133,#630).
 static int st_direnum(httrackp *opt, int argc, char **argv) {
@@ -6268,6 +6631,13 @@ static void threadwait_gated_thread(void *arg) {
   hts_mutexrelease(&threadwait_lock);
 }
 
+static int st_backswap(httrackp *opt, int argc, char **argv) {
+  (void) opt;
+  (void) argc;
+  (void) argv;
+  return back_selftest_slot_swap();
+}
+
 static int st_threadwait(httrackp *opt, int argc, char **argv) {
   int err = 0;
   int i, round;
@@ -6324,6 +6694,109 @@ static int st_threadwait(httrackp *opt, int argc, char **argv) {
   return err;
 }
 
+/* #794: hts_gmtime() must own its output. The table is an independent oracle;
+   the threaded phase is what corrupts if it ever goes back to gmtime()'s
+   shared static. */
+#define GMTIME_THREADS 8
+#define GMTIME_ROUNDS 50000
+
+static const struct {
+  time_t t;
+  int year, mon, mday, hour, min, sec, wday, yday;
+} gmtime_refs[] = {
+    {(time_t) 0, 70, 0, 1, 0, 0, 0, 4, 0},
+    {(time_t) 951782400, 100, 1, 29, 0, 0, 0, 2, 59}, /* a leap day */
+    {(time_t) 1000000000, 101, 8, 9, 1, 46, 40, 0, 251},
+    {(time_t) 2147483647, 138, 0, 19, 3, 14, 7, 2, 18}, /* 32-bit ceiling */
+};
+
+#define GMTIME_REFS ((int) (sizeof(gmtime_refs) / sizeof(gmtime_refs[0])))
+
+static hts_boolean gmtime_ref_matches(int i, const struct tm *tm) {
+  if (tm->tm_year != gmtime_refs[i].year || tm->tm_mon != gmtime_refs[i].mon ||
+      tm->tm_mday != gmtime_refs[i].mday ||
+      tm->tm_hour != gmtime_refs[i].hour || tm->tm_min != gmtime_refs[i].min ||
+      tm->tm_sec != gmtime_refs[i].sec || tm->tm_wday != gmtime_refs[i].wday ||
+      tm->tm_yday != gmtime_refs[i].yday)
+    return HTS_FALSE;
+  return HTS_TRUE;
+}
+
+static htsmutex gmtime_lock = HTSMUTEX_INIT;
+static int gmtime_bad = 0;
+
+static void gmtime_thread(void *arg) {
+  const int i = *(const int *) arg;
+  int bad = 0, round;
+
+  for (round = 0; round < GMTIME_ROUNDS; round++) {
+    struct tm tmv;
+
+    if (!hts_gmtime(gmtime_refs[i].t, &tmv) || !gmtime_ref_matches(i, &tmv))
+      bad++;
+  }
+  hts_mutexlock(&gmtime_lock);
+  gmtime_bad += bad;
+  hts_mutexrelease(&gmtime_lock);
+}
+
+static int st_gmtime(httrackp *opt, int argc, char **argv) {
+  static int idx[GMTIME_THREADS];
+  int err = 0, i;
+
+  (void) opt;
+  (void) argc;
+  (void) argv;
+
+  for (i = 0; i < GMTIME_REFS; i++) {
+    struct tm tmv;
+
+    if (!hts_gmtime(gmtime_refs[i].t, &tmv)) {
+      fprintf(stderr, "gmtime: conversion #%d failed\n", i);
+      err = 1;
+    } else if (!gmtime_ref_matches(i, &tmv)) {
+      fprintf(stderr,
+              "gmtime: #%d gave %04d-%02d-%02d %02d:%02d:%02d (wday %d, "
+              "yday %d)\n",
+              i, tmv.tm_year + 1900, tmv.tm_mon + 1, tmv.tm_mday, tmv.tm_hour,
+              tmv.tm_min, tmv.tm_sec, tmv.tm_wday, tmv.tm_yday);
+      err = 1;
+    }
+  }
+
+  /* the return is the only failure signal the callers have, so a helper that
+     always claims success leaves them formatting an uninitialised struct tm.
+     Out of range for a 64-bit time_t: NULL from gmtime_r, EINVAL from
+     _gmtime64_s. */
+  if (sizeof(time_t) >= 8) {
+    const time_t beyond = (time_t) INT64_MAX;
+    struct tm tmv;
+
+    if (hts_gmtime(beyond, &tmv)) {
+      fprintf(stderr,
+              "gmtime: an out-of-range time_t was reported converted\n");
+      err = 1;
+    }
+  }
+
+  for (i = 0; i < GMTIME_THREADS; i++) {
+    idx[i] = i % GMTIME_REFS;
+    if (hts_newthread(gmtime_thread, &idx[i]) != 0) {
+      fprintf(stderr, "gmtime: cannot spawn\n");
+      return 1;
+    }
+  }
+  htsthread_wait();
+  if (gmtime_bad != 0) {
+    fprintf(stderr, "gmtime: %d/%d concurrent conversions were corrupt\n",
+            gmtime_bad, GMTIME_THREADS * GMTIME_ROUNDS);
+    err = 1;
+  }
+
+  printf("gmtime self-test: %s\n", err ? "FAIL" : "OK");
+  return err;
+}
+
 #define CHANGES_RACE_FILES 8
 #define CHANGES_RACE_ROUNDS 400
 
@@ -6374,7 +6847,7 @@ static int st_changes_race(httrackp *opt, int argc, char **argv) {
     return 1;
   }
   strcpybuff(base, argv[0]);
-  if (base[0] != '\0' && base[strlen(base) - 1] != '/')
+  if (base[0] != '\0' && hts_lastchar(base) != '/')
     strcatbuff(base, "/");
   StringCopy(opt->path_html, base);
   StringCopy(opt->path_html_utf8, base);
@@ -6445,6 +6918,88 @@ static int st_changes_race(httrackp *opt, int argc, char **argv) {
   return err;
 }
 
+/* The x[strlen(x) - 1] class (#770). The string starts mid-arena so the byte
+   it must not touch is a real neighbour; poisoned with '#', not 0, or a stray
+   NUL terminator would read as untouched. */
+static int st_lastchar(httrackp *opt, int argc, char **argv) {
+  enum { off = 8 };
+
+  char arena[16];
+  char *const s = &arena[off];
+  const int guard = off - 1; /* what the old idiom clobbers */
+  int err = 0;
+
+  (void) opt;
+  (void) argc;
+  (void) argv;
+
+#define REPOISON(str)                                                          \
+  do {                                                                         \
+    memset(arena, '#', sizeof(arena));                                         \
+    strlcpybuff(s, (str), sizeof(arena) - off);                                \
+  } while (0)
+#define CHECK(cond)                                                            \
+  do {                                                                         \
+    if (!(cond)) {                                                             \
+      printf("  FAIL line %d: %s\n", __LINE__, #cond);                         \
+      err = 1;                                                                 \
+    }                                                                          \
+  } while (0)
+
+  /* the empty string: every helper must report "nothing" and touch nothing */
+  REPOISON("");
+  CHECK(hts_lastchar(s) == '\0');
+  CHECK(arena[guard] == '#');
+  REPOISON("");
+  CHECK(hts_striplastchar(s, '/') == HTS_FALSE);
+  CHECK(arena[guard] == '#');
+  CHECK(s[0] == '\0');
+  REPOISON("");
+  CHECK(hts_choplastchar(s) == HTS_FALSE);
+  CHECK(arena[guard] == '#');
+  CHECK(s[0] == '\0');
+
+  /* a '/' sitting where the underflow would land must not be mistaken for the
+     string's own last byte -- this is the #768 shape */
+  REPOISON("");
+  arena[guard] = '/';
+  CHECK(hts_lastchar(s) == '\0');
+  CHECK(hts_striplastchar(s, '/') == HTS_FALSE);
+  CHECK(arena[guard] == '/');
+
+  /* non-empty: ordinary behaviour */
+  REPOISON("ab/");
+  CHECK(hts_lastchar(s) == '/');
+  CHECK(hts_striplastchar(s, '/') == HTS_TRUE);
+  CHECK(strcmp(s, "ab") == 0);
+  CHECK(hts_striplastchar(s, '/') == HTS_FALSE);
+  CHECK(strcmp(s, "ab") == 0);
+  CHECK(hts_choplastchar(s) == HTS_TRUE);
+  CHECK(strcmp(s, "a") == 0);
+  CHECK(hts_choplastchar(s) == HTS_TRUE);
+  CHECK(s[0] == '\0');
+  CHECK(arena[guard] == '#');
+
+  /* one-character string: the boundary the guards get wrong */
+  REPOISON("/");
+  CHECK(hts_lastchar(s) == '/');
+  CHECK(hts_striplastchar(s, '/') == HTS_TRUE);
+  CHECK(s[0] == '\0');
+  CHECK(arena[guard] == '#');
+
+  /* control: the canary must be able to fail, or the checks above prove
+     nothing. Clobber it exactly as the unguarded idiom would. */
+  REPOISON("");
+  s[-1] = '\0';
+  CHECK(arena[guard] != '#');
+
+#undef REPOISON
+#undef CHECK
+
+  printf("lastchar self-test: %s\n", err ? "FAIL" : "OK");
+  return err;
+}
+
 /* ------------------------------------------------------------ */
 /* Registry: name -> handler, with a usage hint and a one-line description. */
 /* ------------------------------------------------------------ */
@@ -6500,12 +7055,18 @@ static const struct selftest_entry {
     {"strsafe", "[overflow|overflow-buff|overflow-src [str]]",
      "bounded string-op self-test", st_strsafe},
     {"copyopt", "", "copy_htsopt option-copy self-test", st_copyopt},
+    {"lastchar", "", "last-char helpers never index before the buffer (#770)",
+     st_lastchar},
     {"changes", "", "--changes bucket accounting and JSON escaping (#714)",
      st_changes},
     {"changes-race", "<dir>", "--changes under a late transfer thread (#714)",
      st_changes_race},
     {"threadwait", "", "htsthread_wait() joins threads spawned just before it",
      st_threadwait},
+    {"gmtime", "",
+     "hts_gmtime() fills the caller's buffer, not a static (#794)", st_gmtime},
+    {"backswap", "", "which backlog slots may be swapped to the ready table",
+     st_backswap},
     {"pause", "", "randomized inter-file pause target self-test", st_pause},
     {"relative", "<link> <curr-file>", "relative link between two paths",
      st_relative},
@@ -6538,6 +7099,8 @@ static const struct selftest_entry {
      st_growsize},
     {"addlink", "", "htsAddLink codebase walk over an empty current path",
      st_addlink},
+    {"logcallback", "", "log callback must not consume the log file's va_list",
+     st_logcallback},
     {"cache", "<dir>", "cache read/write round-trip self-test", st_cache},
     {"cacheindex", "", "cache-index (.ndx) parse must stay in bounds",
      st_cacheindex},
@@ -6596,6 +7159,9 @@ static const struct selftest_entry {
      st_warc_verbatim},
     {"warc-surt", "", "SURT canonicalization of the CDXJ sort key",
      st_warc_surt},
+    {"warc-longurl", "<dir>",
+     "a URL past the header-format buffer still reaches the archive",
+     st_warc_longurl},
     {"longpath", "<dir>",
      "round-trip a >MAX_PATH file through the _w* wrappers (\\\\?\\ on "
      "Windows)",
@@ -6603,6 +7169,10 @@ static const struct selftest_entry {
     {"mirrorio", "<dir>",
      "round-trip a long+non-ASCII path through the mirror I/O wrappers",
      st_mirrorio},
+    {"renameover", "<dir>",
+     "hts_rename_over(): replace dst, but never delete a dst it did not "
+     "replace",
+     st_renameover},
     {"direnum", "<dir>",
      "enumerate a long+non-ASCII directory through opendir/readdir",
      st_direnum},

src/htsserver.c

@@ -1050,9 +1050,9 @@ int smallserver(T_SOC soc, char *url, char *method, char *data, char *path) {
                 if (!linput(fp, line, sizeof(line) - 2)) {
                   *str = '\0';
                 }
-                if (*str && str[strlen(str) - 1] == '\\') {
+                if (hts_lastchar(str) == '\\') {
                   nocr = 1;
-                  str[strlen(str) - 1] = '\0';
+                  hts_striplastchar(str, '\\');
                 }
                 while(*str) {
                   char *pos;
@@ -1169,11 +1169,8 @@ int smallserver(T_SOC soc, char *url, char *method, char *data, char *path) {
                           char *rpath = (char *) adr;
 
                           //find_handle h;
-                          if (rpath[0]) {
-                            if (rpath[strlen(rpath) - 1] == '/') {
-                              rpath[strlen(rpath) - 1] = '\0';  /* note: patching stored (inhash) value */
-                            }
-                          }
+                          /* note: patching stored (inhash) value */
+                          hts_striplastchar(rpath, '/');
                           {
                             const char *profiles = hts_getcategories(rpath, 0);
                             const char *categ = hts_getcategories(rpath, 1);

src/htssinglefile.c

@@ -1109,7 +1109,7 @@ hts_boolean singlefile_rewrite_file(httrackp *opt, const char *root,
                    HTS_ACCESS_FILE);
 #endif
     if (ok)
-      ok = hts_rename_over(StringBuff(tmp), page_path);
+      ok = hts_rename_over(opt, StringBuff(tmp), page_path);
     if (!ok) {
       hts_log_print(opt, LOG_ERROR, "single-file: could not rewrite %s",
                     page_path);

src/htstools.c

@@ -985,10 +985,7 @@ HTSEXT_API int hts_buildtopindex(httrackp * opt, const char *path,
       && toptemplate_bodycat) {
 
     strcpybuff(rpath, path);
-    if (rpath[0]) {
-      if (rpath[strlen(rpath) - 1] == '/')
-        rpath[strlen(rpath) - 1] = '\0';
-    }
+    hts_striplastchar(rpath, '/');
 
     fpo = fopen(fconcat(catbuff, sizeof(catbuff), rpath, "/index.html"), "wb");
     if (fpo) {
@@ -1201,11 +1198,8 @@ HTSEXT_API char *hts_getcategories(char *path, int type) {
   find_handle h;
   coucal hashCateg = NULL;
 
-  if (rpath[0]) {
-    if (rpath[strlen(rpath) - 1] == '/') {
-      rpath[strlen(rpath) - 1] = '\0';  /* note: patching stored (inhash) value */
-    }
-  }
+  /* note: patching stored (inhash) value */
+  hts_striplastchar(rpath, '/');
   h = hts_findfirst(rpath);
   if (h) {
     String iname = STRING_EMPTY;
@@ -1302,7 +1296,7 @@ HTSEXT_API find_handle hts_findfirst(char *path) {
 
           strcpybuff(rpath, path);
           if (rpath[0]) {
-            if (rpath[strlen(rpath) - 1] != '\\')
+            if (hts_lastchar(rpath) != '\\')
               strcatbuff(rpath, "\\");
           }
           strcatbuff(rpath, "*.*");
@@ -1314,7 +1308,7 @@ HTSEXT_API find_handle hts_findfirst(char *path) {
         strcpybuff(find->path, path);
         {
           if (find->path[0]) {
-            if (find->path[strlen(find->path) - 1] != '/')
+            if (hts_lastchar(find->path) != '/')
               strcatbuff(find->path, "/");
           }
         }
@@ -1444,14 +1438,75 @@ HTSEXT_API hts_boolean hts_findissystem(find_handle find) {
   return 0;
 }
 
-hts_boolean hts_rename_over(const char *src, const char *dst) {
+/* Park cdst under a free sibling name; caside receives it. */
+static hts_boolean rename_park_aside(char *caside, size_t size,
+                                     const char *cdst) {
+  int i;
+
+  for (i = 0; i < 16; i++) {
+    if (!slprintfbuff(caside, size, "%s.hts-old%d", cdst, i))
+      return HTS_FALSE;
+    /* Skip a name the mirror already holds: POSIX rename() would clobber it
+       (#774). A non-regular entry reads as free and the rename refuses it. */
+    if (fexist_utf8(caside))
+      continue;
+    if (RENAME(cdst, caside) == 0)
+      return HTS_TRUE;
+  }
+  return HTS_FALSE;
+}
+
+/* cdst is in the way of the move: park it, retry, and put it back if the retry
+   fails too. Unlinking it instead would leave nothing at all (#790). */
+static hts_boolean rename_over_aside(httrackp *opt, const char *csrc,
+                                     const char *cdst) {
+  char caside[CATBUFF_SIZE];
+  int err;
+
+  /* Only a regular file may be parked: a directory in the way is not what the
+     caller asked to replace, and parking it orphans it (UNLINK cannot drop). */
+  if (!fexist_utf8(cdst))
+    return HTS_FALSE;
+  if (!rename_park_aside(caside, sizeof(caside), cdst))
+    return HTS_FALSE;
+  if (RENAME(csrc, cdst) == 0) {
+    (void) UNLINK(caside);
+    return HTS_TRUE;
+  }
+  err = errno;
+  /* Retry once, then name the parked copy: nothing else on disk or in the log
+     points at it, and an --update purge would delete it unnoticed. */
+  if (RENAME(caside, cdst) != 0 && RENAME(caside, cdst) != 0)
+    hts_log_print(opt, LOG_WARNING | LOG_ERRNO,
+                  "could not put %s back; its previous content is now %s", cdst,
+                  caside);
+  errno = err;
+  return HTS_FALSE;
+}
+
+hts_boolean hts_rename_over(httrackp *opt, const char *src, const char *dst) {
   char csrc[CATBUFF_SIZE], cdst[CATBUFF_SIZE];
 
   fconv(csrc, sizeof(csrc), src);
   fconv(cdst, sizeof(cdst), dst);
   if (RENAME(csrc, cdst) == 0)
     return HTS_TRUE;
-  /* RENAME does not clobber an existing target on Windows. */
-  (void) UNLINK(cdst);
-  return RENAME(csrc, cdst) == 0 ? HTS_TRUE : HTS_FALSE;
+  /* Only a dst in the way is something the fallback can clear, and the CRT maps
+     that to EEXIST; it keeps EACCES for a src another process holds, where the
+     retry would fail the same way. The src check covers a CRT that reports
+     neither. */
+  const int err = errno;
+
+  if (err != EEXIST || !fexist_utf8(src))
+    return HTS_FALSE;
+  return rename_over_aside(opt, csrc, cdst);
+}
+
+hts_boolean hts_rename_over_aside_selftest(httrackp *opt, const char *src,
+                                           const char *dst) {
+  char csrc[CATBUFF_SIZE], cdst[CATBUFF_SIZE];
+
+  fconv(csrc, sizeof(csrc), src);
+  fconv(cdst, sizeof(cdst), dst);
+  return rename_over_aside(opt, csrc, cdst);
 }

src/htstools.h

@@ -137,9 +137,17 @@ HTSEXT_API hts_boolean hts_findisdir(find_handle find);
 HTSEXT_API hts_boolean hts_findisfile(find_handle find);
 HTSEXT_API hts_boolean hts_findissystem(find_handle find);
 
-/* Move src onto dst, replacing an existing dst; HTS_TRUE on success. Both
-   paths are fconv()'d. */
-hts_boolean hts_rename_over(const char *src, const char *dst);
+/* Move src onto dst, replacing an existing dst; HTS_TRUE on success. Both paths
+   are fconv()'d. A dst in the way is parked under a sibling name rather than
+   removed, so the old content survives a failure: back at dst, or under that
+   sibling (named in the log) when the move back failed too. Not atomic: a crash
+   between the two renames leaves dst absent and its content beside it. */
+hts_boolean hts_rename_over(httrackp *opt, const char *src, const char *dst);
+
+/* Selftest hook: run the aside fallback directly, on a platform whose rename()
+   never reaches it. Both paths are fconv()'d. */
+hts_boolean hts_rename_over_aside_selftest(httrackp *opt, const char *src,
+                                           const char *dst);
 
 #endif
 

src/htswarc.c

@@ -127,24 +127,32 @@ static void wbuf_free(wbuf *b) {
   b->len = b->cap = 0;
 }
 
-/* Append n bytes; returns 0 on success, -1 on OOM/overflow. */
-static int wbuf_add(wbuf *b, const void *p, size_t n) {
+/* Make room for n more bytes; returns 0 on success, -1 on OOM/overflow. */
+static int wbuf_reserve(wbuf *b, size_t n) {
+  size_t ncap;
+  char *nd;
   if (n > (size_t) -1 - b->len)
     return -1;
-  if (b->len + n > b->cap) {
-    size_t ncap = b->cap ? b->cap : 256;
-    char *nd;
-    while (ncap < b->len + n) {
-      if (ncap > (size_t) -1 / 2)
-        return -1;
-      ncap *= 2;
-    }
-    nd = realloct(b->data, ncap);
-    if (nd == NULL)
+  if (b->len + n <= b->cap)
+    return 0;
+  ncap = b->cap ? b->cap : 256;
+  while (ncap < b->len + n) {
+    if (ncap > (size_t) -1 / 2)
       return -1;
-    b->data = nd;
-    b->cap = ncap;
+    ncap *= 2;
   }
+  nd = realloct(b->data, ncap);
+  if (nd == NULL)
+    return -1;
+  b->data = nd;
+  b->cap = ncap;
+  return 0;
+}
+
+/* Append n bytes; returns 0 on success, -1 on OOM/overflow. */
+static int wbuf_add(wbuf *b, const void *p, size_t n) {
+  if (wbuf_reserve(b, n) != 0)
+    return -1;
   memcpy(b->data + b->len, p, n);
   b->len += n;
   return 0;
@@ -156,16 +164,32 @@ static int wbuf_puts(wbuf *b, const char *s) {
 
 static int wbuf_printf(wbuf *b, const char *fmt, ...) HTS_PRINTF_FUN(2, 3);
 
+/* A header line carrying a URL has no useful bound, and giving up here loses
+   the whole record, so anything past the stack buffer is formatted into the
+   wbuf itself rather than rejected (#785). */
 static int wbuf_printf(wbuf *b, const char *fmt, ...) {
   char tmp[1024];
+  size_t need;
   int n;
   va_list ap;
   va_start(ap, fmt);
   n = vsnprintf(tmp, sizeof(tmp), fmt, ap);
   va_end(ap);
-  if (n < 0 || (size_t) n >= sizeof(tmp))
+  if (n < 0)
     return -1;
-  return wbuf_add(b, tmp, (size_t) n);
+  if ((size_t) n < sizeof(tmp))
+    return wbuf_add(b, tmp, (size_t) n);
+  need = (size_t) n + 1; /* +1: vsnprintf always writes the NUL */
+  if (wbuf_reserve(b, need) != 0)
+    return -1;
+  va_start(ap, fmt);
+  n = vsnprintf(b->data + b->len, need, fmt, ap);
+  va_end(ap);
+  /* Never advance past what was reserved, whatever the second pass returns. */
+  if (n < 0 || (size_t) n >= need)
+    return -1;
+  b->len += (size_t) n; /* the NUL is scratch, overwritten by the next append */
+  return 0;
 }
 
 /* ---- gzip-per-record member writer (mirrors ae_write_packed) ---- */
@@ -1090,7 +1114,7 @@ static void warc_wacz_package(warc_writer *w) {
     hts_log_print(w->opt, LOG_WARNING,
                   "WACZ: packaging failed, kept existing %s untouched",
                   waczpath);
-  } else if (!hts_rename_over(tmppath, waczpath)) {
+  } else if (!hts_rename_over(w->opt, tmppath, waczpath)) {
     (void) UNLINK(fconv(catbuff, sizeof(catbuff), tmppath));
     hts_log_print(w->opt, LOG_WARNING | LOG_ERRNO,
                   "WACZ: could not finalize %s", waczpath);
@@ -1368,16 +1392,8 @@ warc_writer *warc_open(httrackp *opt, const char *path) {
     char ts[32];
     time_t t = time(NULL);
     struct tm tmv;
-#if defined(_WIN32)
-    struct tm *g = gmtime(&t);
-    if (g != NULL)
-      tmv = *g;
-    else
+    if (!hts_gmtime(t, &tmv))
       memset(&tmv, 0, sizeof(tmv));
-#else
-    if (gmtime_r(&t, &tmv) == NULL)
-      memset(&tmv, 0, sizeof(tmv));
-#endif
     strftime(ts, sizeof(ts), "%Y%m%d%H%M%S", &tmv);
     snprintf(catbuff, sizeof(catbuff), "httrack-%s.warc.gz", ts);
     path =
@@ -1552,8 +1568,8 @@ static hts_boolean warc_commit(warc_writer *w) {
   if (!w->protect_prev)
     return HTS_TRUE; /* nothing was there to lose: written in place */
 
-  /* hts_rename_over unlinks its destination when the source is missing, so
-     every segment has to be on disk before the first rename. */
+  /* All or nothing: a swap stopping halfway would mix this run's segments with
+     the previous one's, so require every temp before renaming any. */
   swap = w->opened && !w->failed && w->unbacked_revisits == 0;
   for (s = 0; s < nseg && swap; s++) {
     snprintf(tmpbuf, sizeof(tmpbuf), "%s" WARC_TMP_SUFFIX,
@@ -1565,7 +1581,7 @@ static hts_boolean warc_commit(warc_writer *w) {
     for (s = 0; s < nseg; s++) {
       const char *final = warc_seg_path(w, s, finalbuf, sizeof(finalbuf));
       snprintf(tmpbuf, sizeof(tmpbuf), "%s" WARC_TMP_SUFFIX, final);
-      if (!hts_rename_over(tmpbuf, final)) {
+      if (!hts_rename_over(w->opt, tmpbuf, final)) {
         hts_log_print(w->opt, LOG_ERROR | LOG_ERRNO,
                       "WARC: could not replace %s", final);
         return HTS_FALSE;
@@ -1684,6 +1700,10 @@ int warc_write_transaction(warc_writer *w, const char *target_uri,
   if (is_update_unchanged) {
     is_revisit = 1;
     profile = "http://netpreserve.org/warc/1.1/revisit/server-not-modified";
+    /* Replay resolves a revisit by this field alone, and a 304 stands in for
+       the same URL. No WARC-Refers-To-Date to go with it: the cache keeps the
+       document's Last-Modified, never the previous capture time. */
+    refers_uri = target_uri;
     /* Served from cache: the payload sits in the previous archive, not here. */
     w->unbacked_revisits++;
   } else if (have_pdig && w->seen != NULL) {

src/proxy/proxytrack.c

@@ -520,12 +520,13 @@ static void proxytrack_add_DAV_Item(String * item, String * buff,
                                     const char *filename, size_t size,
                                     time_t timestamp, const char *mime,
                                     int isDir, int isRoot, int isDefault) {
-  struct tm *timetm;
+  struct tm timetmbuf;
+  struct tm *timetm = &timetmbuf;
 
   if (timestamp == (time_t) 0 || timestamp == (time_t) - 1) {
     timestamp = time(NULL);
   }
-  if ((timetm = gmtime(&timestamp)) != NULL) {
+  if (hts_gmtime(timestamp, timetm)) {
     char tms[256 + 1];
     const char *name;
 
@@ -747,7 +748,8 @@ static PT_Element proxytrack_process_DAV_Request(PT_Indexes indexes,
             const char *thisUrl = list[i];
             const char *mimeType = "application/octet-stream";
             unsigned int thisUrlLen = (unsigned int) strlen(thisUrl);
-            int thisIsDir = (thisUrl[thisUrlLen - 1] == '/') ? 1 : 0;
+            /* the folder's default document is enumerated as an empty name */
+            int thisIsDir = (hts_lastchar(thisUrl) == '/') ? 1 : 0;
 
             /* Item URL */
             StringRoom(itemUrl,
@@ -852,8 +854,7 @@ static PT_Element proxytrack_process_HTTP_List(PT_Indexes indexes,
     for(isDir = 1; isDir >= 0; isDir--) {
       for(i = 0; list[i] != NULL; i++) {
         char *thisUrl = list[i];
-        unsigned int thisUrlLen = (unsigned int) strlen(thisUrl);
-        int thisIsDir = (thisUrl[thisUrlLen - 1] == '/') ? 1 : 0;
+        int thisIsDir = (hts_lastchar(thisUrl) == '/') ? 1 : 0;
 
         if (thisIsDir == isDir) {
           if (isDir)

src/proxy/proxytrack.h

@@ -360,21 +360,14 @@ HTS_UNUSED static struct tm *convert_time_rfc822(struct tm *result, const char *
 HTS_UNUSED static struct tm PT_GetTime(time_t t) {
   struct tm tmbuf;
 
-#ifdef _WIN32
-  struct tm *tm = gmtime(&t);
-#else
-  struct tm *tm = gmtime_r(&t, &tmbuf);
-#endif
-  if (tm != NULL)
-    return *tm;
-  else {
+  if (!hts_gmtime(t, &tmbuf)) {
     /* an all-zero tm has tm_mday == 0, which the ARC date field prints as a
        day of "00"; the epoch is the conventional "date unknown" */
     memset(&tmbuf, 0, sizeof(tmbuf));
     tmbuf.tm_year = 70;
     tmbuf.tm_mday = 1;
-    return tmbuf;
   }
+  return tmbuf;
 }
 HTS_UNUSED static int set_filetime(const char *file, struct tm *tm_time) {
   struct utimbuf tim;

tests/01_engine-addlink.test

@@ -4,4 +4,5 @@
 
 set -euo pipefail
 
-httrack -O /dev/null -#test=addlink | grep -q "addlink self-test OK"
+out=$(httrack -O /dev/null -#test=addlink)
+grep -q "addlink self-test OK" <<<"$out"

tests/01_engine-backswap.test

@@ -0,0 +1,9 @@
+#!/bin/bash
+#
+
+set -euo pipefail
+
+# A ready slot still owning a temporary must stay in memory: swapping it out
+# clears the entry, which unlinks the re-fetch backup (#771).
+out=$(httrack -O /dev/null -#test=backswap)
+grep -q "backswap self-test: OK" <<<"$out"

tests/01_engine-changes.test

@@ -3,25 +3,13 @@
 
 set -euo pipefail
 
-tmpdir=$(mktemp -d "${TMPDIR:-/tmp}/httrack_changes_st.XXXXXX") || exit 1
-trap 'rm -rf "$tmpdir"' EXIT HUP INT QUIT PIPE TERM
+testdir=$(cd "$(dirname "$0")" && pwd)
+# shellcheck source=tests/testlib.sh
+. "${testdir}/testlib.sh"
 
-# No pipe into grep: SIGPIPE would mask a failing exit status.
-expect_ok() {
-    local label="$1" out
-    shift
-    out=$("$@" 2>&1) || {
-        echo "FAIL: ${label} exited non-zero: ${out}"
-        exit 1
-    }
-    case "$out" in
-    *"${label}: OK"*) ;;
-    *)
-        echo "FAIL: ${out}"
-        exit 1
-        ;;
-    esac
-}
+tmpdir=$(mktemp -d "${TMPDIR:-/tmp}/httrack_changes_st.XXXXXX") || exit 1
+trap 'set +e; rm -rf "$tmpdir"' EXIT
+trap 'rm -rf "$tmpdir"' HUP INT QUIT PIPE TERM
 
 # --changes bucket accounting and JSON escaping (#714).
 expect_ok "changes self-test" httrack -O "${tmpdir}/o1" -#test=changes run

tests/01_engine-cmdline-split.test

@@ -5,4 +5,5 @@ set -euo pipefail
 
 # webhttrack posts its command line as one string: the argv split must grow past
 # 1024 arguments and keep a quote inside a value out of the option parser.
-httrack -O /dev/null -#test=cmdline-split run | grep -q "cmdline-split self-test OK"
+out=$(httrack -O /dev/null -#test=cmdline-split run)
+grep -q "cmdline-split self-test OK" <<<"$out"

tests/01_engine-cmdline.test

@@ -11,7 +11,8 @@
 set -euo pipefail
 
 tmp=$(mktemp -d "${TMPDIR:-/tmp}/httrack_cmdline.XXXXXX") || exit 1
-trap 'rm -rf "$tmp"' EXIT HUP INT QUIT PIPE TERM
+trap 'set +e; rm -rf "$tmp"' EXIT
+trap 'rm -rf "$tmp"' HUP INT QUIT PIPE TERM
 
 echo '<html><body>hello</body></html>' >"$tmp/index.html"
 

tests/01_engine-cookieimport.test

@@ -7,6 +7,7 @@ set -euo pipefail
 # cookies *@*.txt) from a long, non-ASCII folder through the UTF-8/long-path
 # file wrappers (#133,#630).
 dir=$(mktemp -d)
-trap 'rm -rf "$dir"' EXIT
+trap 'set +e; rm -rf "$dir"' EXIT
 
-httrack -O /dev/null -#test=cookieimport "$dir" | grep -q "cookieimport:.*OK"
+out=$(httrack -O /dev/null -#test=cookieimport "$dir")
+grep -q "cookieimport:.*OK" <<<"$out"

tests/01_engine-direnum.test

@@ -6,6 +6,7 @@ set -euo pipefail
 # Drives -#test=direnum: enumerate a long+non-ASCII directory through the
 # opendir/readdir wrappers, checking each child round-trips as UTF-8 (#133,#630).
 dir=$(mktemp -d)
-trap 'rm -rf "$dir"' EXIT
+trap 'set +e; rm -rf "$dir"' EXIT
 
-httrack -O /dev/null -#test=direnum "$dir" | grep -q "direnum:.*OK"
+out=$(httrack -O /dev/null -#test=direnum "$dir")
+grep -q "direnum:.*OK" <<<"$out"

tests/01_engine-doitlog.test

@@ -28,7 +28,8 @@ case "$bin" in
 esac
 
 tmp=$(mktemp -d "${TMPDIR:-/tmp}/httrack_doitlog.XXXXXX") || exit 1
-trap 'rm -rf "$tmp"' EXIT HUP INT QUIT PIPE TERM
+trap 'set +e; rm -rf "$tmp"' EXIT
+trap 'rm -rf "$tmp"' HUP INT QUIT PIPE TERM
 
 site="$tmp/site"
 out="$tmp/out"

tests/01_engine-escape-room.test

@@ -4,4 +4,5 @@
 set -euo pipefail
 
 # HT_ADD_HTMLESCAPED* must reserve the escaper's worst case (6 for _full).
-httrack -O /dev/null -#test=escape-room run | grep -q "escape-room self-test OK"
+out=$(httrack -O /dev/null -#test=escape-room run)
+grep -q "escape-room self-test OK" <<<"$out"

tests/01_engine-filelist.test

@@ -8,7 +8,8 @@
 set -euo pipefail
 
 tmp=$(mktemp -d "${TMPDIR:-/tmp}/httrack_filelist.XXXXXX") || exit 1
-trap 'rm -rf "$tmp"' EXIT HUP INT QUIT PIPE TERM
+trap 'set +e; rm -rf "$tmp"' EXIT
+trap 'rm -rf "$tmp"' HUP INT QUIT PIPE TERM
 
 echo '<html><body>hi</body></html>' >"$tmp/index.html"
 

tests/01_engine-footer-overflow.test

@@ -18,7 +18,7 @@ MINGW* | MSYS* | CYGWIN*) exit 77 ;;
 esac
 
 dir=$(mktemp -d)
-trap 'rm -rf "$dir"' EXIT
+trap 'set +e; rm -rf "$dir"' EXIT
 
 # A few-hundred-char file path (kept well under the URL length limit) makes the
 # {path} field long.
@@ -50,7 +50,7 @@ httrack "file://$deep/index.html" -O "$mir" -%F "$footer" -q -s0 -%v0 \
 
 # The crawled page must exist (proves the URL wasn't rejected for length, so the
 # footer path ran). Look under file/, not $mir, to skip the makeindex top index.
-find "$mir/file" -name index.html | grep -q . || {
+test -n "$(find "$mir/file" -name index.html)" || {
     echo "page not mirrored; the oversized-footer path was not exercised" >&2
     exit 1
 }

tests/01_engine-fsize.test

@@ -6,7 +6,7 @@
 set -euo pipefail
 
 dir=$(mktemp -d)
-trap 'rm -rf "$dir"' EXIT
+trap 'set +e; rm -rf "$dir"' EXIT
 
 rc=0
 out=$(httrack -#test=fsize "$dir") || rc=$?

tests/01_engine-ftp-line.test

@@ -4,4 +4,5 @@
 set -euo pipefail
 
 # get_ftp_line bounds a hostile CRLF-less FTP reply into its 1024-byte buffer.
-httrack -O /dev/null -#test=ftp-line run | grep -q "ftp-line self-test OK"
+out=$(httrack -O /dev/null -#test=ftp-line run)
+grep -q "ftp-line self-test OK" <<<"$out"

tests/01_engine-ftp-userpass.test

@@ -4,4 +4,5 @@
 set -euo pipefail
 
 # ftp_split_userpass bounds an over-long user:pass@ from a hostile ftp:// URL.
-httrack -O /dev/null -#test=ftp-userpass run | grep -q "ftp-userpass self-test OK"
+out=$(httrack -O /dev/null -#test=ftp-userpass run)
+grep -q "ftp-userpass self-test OK" <<<"$out"

tests/01_engine-gmtime.test

@@ -0,0 +1,21 @@
+#!/bin/bash
+#
+
+set -euo pipefail
+
+testdir=$(cd "$(dirname "$0")" && pwd)
+# shellcheck source=tests/testlib.sh
+. "${testdir}/testlib.sh"
+
+# A non-UTC zone, so a helper that reached for localtime instead of gmtime gives
+# a different answer: CI runners are UTC, where the two agree.
+TZ=XXX5
+export TZ
+
+tmpdir=$(mktemp -d "${TMPDIR:-/tmp}/httrack_gmtime_st.XXXXXX") || exit 1
+trap 'set +e; rm -rf "$tmpdir"' EXIT
+trap 'rm -rf "$tmpdir"' HUP INT QUIT PIPE TERM
+
+# Concurrent conversions do not tread on each other the way gmtime()'s shared
+# static does (#794).
+expect_ok "gmtime self-test" httrack -O "${tmpdir}/o1" -#test=gmtime

tests/01_engine-growsize.test

@@ -10,7 +10,8 @@ echo "$out"
 test "$out" == "growsize self-test OK"
 
 tmp=$(mktemp -d "${TMPDIR:-/tmp}/httrack_growsize.XXXXXX")
-trap 'rm -rf "$tmp"' EXIT HUP INT QUIT PIPE TERM
+trap 'set +e; rm -rf "$tmp"' EXIT
+trap 'rm -rf "$tmp"' HUP INT QUIT PIPE TERM
 
 echo '<html><body>hi</body></html>' >"$tmp/index.html"
 printf -- '-*/zzmarker*\n' >"$tmp/rules.txt"
@@ -18,7 +19,7 @@ printf -- '-*/zzmarker*\n' >"$tmp/rules.txt"
 # the rules file lands in the URL/filter string, echoed back by the banner
 run=$(httrack -O "$tmp/out" --quiet -n "-%S" "$tmp/rules.txt" \
     "file://$tmp/index.html" 2>&1) || true
-printf '%s\n' "$run" | grep -q 'zzmarker' || {
+grep -q 'zzmarker' <<<"$run" || {
     echo "FAIL: -%S rules file was not loaded"
     printf '%s\n' "$run"
     exit 1

tests/01_engine-hashtable.test

@@ -6,4 +6,4 @@ set -euo pipefail
 # httrack internal hashtable autotest on 100K keys. Assert the success line (on
 # stderr) so a misrouted registry entry can't pass on exit code alone.
 out=$(httrack -#test=hashtable 100000 2>&1)
-printf '%s\n' "$out" | grep -q "all hashtable tests were successful!" || exit 1
+grep -q "all hashtable tests were successful!" <<<"$out" || exit 1

tests/01_engine-inplace-escape.test

@@ -4,4 +4,5 @@
 set -euo pipefail
 
 # inplace_escape_*() must match escape_*() on a copy: guards the shared helper.
-httrack -O /dev/null -#test=inplace-escape run | grep -q "inplace-escape self-test OK"
+out=$(httrack -O /dev/null -#test=inplace-escape run)
+grep -q "inplace-escape self-test OK" <<<"$out"

tests/01_engine-lastchar.test

@@ -0,0 +1,35 @@
+#!/bin/bash
+#
+# Runs the lastchar self-test (#770), then keeps the idiom it replaced from
+# coming back: x[strlen(x) - 1] indexes one byte before the buffer when x is
+# empty, and the guard is never where the index is.
+
+set -eu
+
+: "${top_srcdir:=..}"
+
+out=$(httrack -#test=lastchar) || {
+    echo "httrack -#test=lastchar exited non-zero: $out" >&2
+    exit 1
+}
+
+# Exact-match the success line so a renamed/removed test can't pass silently.
+test "$out" = "lastchar self-test: OK" || {
+    echo "expected 'lastchar self-test: OK', got: $out" >&2
+    exit 1
+}
+
+# The self-test only covers the helpers, so guard the class at the source: the
+# lone survivor is inside a comment block in htsname.c. coucal is vendored, so
+# its idioms are not ours to police.
+hits=$(command grep -rn 'strlen([^)]*) *- *1\]' "$top_srcdir/src" \
+    --include='*.c' --include='*.h' --exclude-dir=coucal |
+    grep -v 'htsname\.c:.*save\[strlen(save)-1\]' |
+    grep -v 'Replaces s\[strlen(s) - 1\]' |
+    grep -v 'The x\[strlen(x) - 1\] class' || true)
+
+test -z "$hits" || {
+    echo "x[strlen(x) - 1] reintroduced; use hts_lastchar/hts_striplastchar/hts_choplastchar:" >&2
+    echo "$hits" >&2
+    exit 1
+}

tests/01_engine-logcallback.test

@@ -0,0 +1,8 @@
+#!/bin/bash
+#
+# a log callback consumed the va_list the log file's vfprintf() still needed (#801).
+
+set -euo pipefail
+
+out=$(httrack -O /dev/null -#test=logcallback)
+grep -q "logcallback self-test OK" <<<"$out"

tests/01_engine-longpath-io.test

@@ -6,6 +6,7 @@ set -euo pipefail
 # Drives -#test=longpath: a >MAX_PATH round trip exercising hts_pathToUCS2's
 # \\?\ prefixing on Windows (#133); a positive control on POSIX.
 dir=$(mktemp -d)
-trap 'rm -rf "$dir"' EXIT
+trap 'set +e; rm -rf "$dir"' EXIT
 
-httrack -O /dev/null -#test=longpath "$dir" | grep -q "longpath:.*OK"
+out=$(httrack -O /dev/null -#test=longpath "$dir")
+grep -q "longpath:.*OK" <<<"$out"

tests/01_engine-makeindex.test

@@ -6,7 +6,7 @@ set -euo pipefail
 # hts_finish_makeindex writes the footer and gates the refresh meta on a single
 # first link (guards the macro->function extraction).
 dir=$(mktemp -d)
-trap 'rm -rf "$dir"' EXIT
+trap 'set +e; rm -rf "$dir"' EXIT
 
 httrack -O /dev/null -#test=makeindex "$dir" run |
     grep -q "makeindex self-test OK"

tests/01_engine-mirror-io.test

@@ -7,6 +7,7 @@ set -euo pipefail
 # (>MAX_PATH) and non-ASCII, exercising the mirror I/O wrappers the engine's
 # raw file ops now route to on Windows (#133, #630). Positive control on POSIX.
 dir=$(mktemp -d)
-trap 'rm -rf "$dir"' EXIT
+trap 'set +e; rm -rf "$dir"' EXIT
 
-httrack -O /dev/null -#test=mirrorio "$dir" | grep -q "mirrorio:.*OK"
+out=$(httrack -O /dev/null -#test=mirrorio "$dir")
+grep -q "mirrorio:.*OK" <<<"$out"

tests/01_engine-parse.test

@@ -7,7 +7,8 @@
 set -euo pipefail
 
 tmp=$(mktemp -d "${TMPDIR:-/tmp}/httrack_parse.XXXXXX") || exit 1
-trap 'rm -rf "$tmp"' EXIT HUP INT QUIT PIPE TERM
+trap 'set +e; rm -rf "$tmp"' EXIT
+trap 'rm -rf "$tmp"' HUP INT QUIT PIPE TERM
 
 # a minimal valid 1x1 GIF, reused for every referenced asset
 gif() {

tests/01_engine-rcfile.test

@@ -30,7 +30,8 @@ case "$bin" in
 esac
 
 tmp=$(mktemp -d "${TMPDIR:-/tmp}/httrack_rcfile.XXXXXX") || exit 1
-trap 'rm -rf "$tmp"' EXIT HUP INT QUIT PIPE TERM
+trap 'set +e; rm -rf "$tmp"' EXIT
+trap 'rm -rf "$tmp"' HUP INT QUIT PIPE TERM
 
 # HTS_HTTRACKRC is ".httrackrc" on POSIX but "httrackrc" on Windows: write both,
 # each platform reads the one it knows.

tests/01_engine-reconcile.test

@@ -7,7 +7,7 @@
 set -eu
 
 dir=$(mktemp -d)
-trap 'rm -rf "$dir"' EXIT
+trap 'set +e; rm -rf "$dir"' EXIT
 
 out=$(httrack -#test=reconcile "$dir")
 

tests/01_engine-redirect.test

@@ -6,4 +6,5 @@ set -euo pipefail
 # #159: a redirect to a same-file alias (http<->https, user@host, ..) must be
 # followed through, not turned into a self-pointing "moved" stub. The decision
 # helper is exercised by the engine self-test.
-httrack -O /dev/null -#test=redirect-samefile run | grep -q "redirect-samefile self-test OK"
+out=$(httrack -O /dev/null -#test=redirect-samefile run)
+grep -q "redirect-samefile self-test OK" <<<"$out"

tests/01_engine-renameover.test

@@ -0,0 +1,71 @@
+#!/bin/bash
+#
+
+set -euo pipefail
+
+# Drives -#test=renameover: hts_rename_over() must replace an existing dst, and
+# must leave dst alone when the rename failed for a reason moving dst aside
+# cannot fix (#779, #790). The selftest prints the regime and the restore
+# outcome it took; pin both per leg so none can pass having tested another.
+dir=$(mktemp -d)
+trap 'set +e; rm -rf "$dir"' EXIT
+
+case "$(uname -s)" in
+MINGW* | MSYS_NT*) want=fallback ;; # native rename() refuses an existing target
+*) want=clobber ;;
+esac
+
+out=$(httrack -O /dev/null -#test=renameover "$dir")
+grep -q "renameover: OK" <<<"$out"
+grep -q "renameover: regime $want" <<<"$out"
+grep -q "renameover: restore back" <<<"$out"
+
+if [ "$(uname -s)" != "Linux" ]; then
+    echo "renameover: LD_PRELOAD interposition is Linux-only here, skipping"
+    exit 0
+fi
+# A --disable-shared build has nothing to preload; anything else missing is a
+# build problem, not a skip, or the interposed legs would pass vacuously.
+if [ ! -r "${RENAMEFAIL_LA:-}" ]; then
+    echo "renameover: ${RENAMEFAIL_LA:-\$RENAMEFAIL_LA} was not built" >&2
+    exit 1
+fi
+if grep -q "^dlname=''" "$RENAMEFAIL_LA"; then
+    echo "renameover: static-only build, skipping the interposed legs"
+    exit 0
+fi
+if [ ! -r "${RENAMEFAIL_LIB:-}" ]; then
+    echo "renameover: ${RENAMEFAIL_LIB:-\$RENAMEFAIL_LIB} was not built" >&2
+    exit 1
+fi
+
+# An LD_PRELOAD library loads ahead of the executable's own libasan, which ASan
+# refuses by default. The shim allocates nothing, so the ordering is harmless.
+export ASAN_OPTIONS="${ASAN_OPTIONS:+$ASAN_OPTIONS:}verify_asan_link_order=0"
+
+# The aside fallback is dead code on POSIX, so borrow Windows' rename().
+out=$(LD_PRELOAD="$RENAMEFAIL_LIB" httrack -O /dev/null \
+    -#test=renameover "$dir")
+grep -q "renameover: OK" <<<"$out"
+grep -q "renameover: regime fallback" <<<"$out"
+grep -q "renameover: restore back" <<<"$out"
+
+# #790: the move back out of the parked name fails once. Without the retry the
+# old copy stays parked and dst is left absent.
+out=$(RENAMEFAIL_ASIDE_FAILS=1 LD_PRELOAD="$RENAMEFAIL_LIB" httrack -O /dev/null \
+    -#test=renameover "$dir")
+grep -q "renameover: OK" <<<"$out"
+grep -q "renameover: restore back" <<<"$out"
+
+# It keeps failing: the old copy must survive under the parked name, never be
+# deleted, and the call must still report failure.
+out=$(RENAMEFAIL_ASIDE_FAILS=9 LD_PRELOAD="$RENAMEFAIL_LIB" httrack -O /dev/null \
+    -#test=renameover "$dir")
+grep -q "renameover: OK" <<<"$out"
+grep -q "renameover: restore parked" <<<"$out"
+
+# A source another process holds fails with EACCES, which dst had no part in.
+out=$(RENAMEFAIL_MODE=locked LD_PRELOAD="$RENAMEFAIL_LIB" httrack -O /dev/null \
+    -#test=renameover "$dir")
+grep -q "renameover: OK" <<<"$out"
+grep -q "renameover: regime refused" <<<"$out"

tests/01_engine-robots.test

@@ -4,4 +4,5 @@
 set -euo pipefail
 
 # robots.txt RFC 9309 Allow/Disallow precedence (#452): longest match wins.
-httrack -O /dev/null -#test=robots run | grep -q "robots self-test OK"
+out=$(httrack -O /dev/null -#test=robots run)
+grep -q "robots self-test OK" <<<"$out"

tests/01_engine-savename.test

@@ -12,7 +12,7 @@ httrack_bin=$(cd "$(dirname "$(command -v httrack)")" && pwd)/httrack
 
 # scratch dir: body= and cached= write temp files (st-savename-body.tmp, hts-cache/)
 scratch=$(mktemp -d)
-trap 'rm -rf "$scratch"' EXIT
+trap 'set +e; rm -rf "$scratch"' EXIT
 cd "$scratch"
 
 run() {

tests/01_engine-selftest-dispatch.test

@@ -7,11 +7,11 @@ set -eu
 
 # Bare -#test lists known tests (printed to stderr).
 list=$(httrack -#test 2>&1)
-printf '%s\n' "$list" | grep -q "filter" || exit 1
-printf '%s\n' "$list" | grep -q "cache-writefail" || exit 1
+grep -q "filter" <<<"$list" || exit 1
+grep -q "cache-writefail" <<<"$list" || exit 1
 
 # Unknown name: non-zero exit + diagnostic, and no test result line.
 rc=0
 err=$(httrack -#test=bogus 2>&1) || rc=$?
 test "$rc" -ne 0 || exit 1
-printf '%s\n' "$err" | grep -q "Unknown self-test" || exit 1
+grep -q "Unknown self-test" <<<"$err" || exit 1

tests/01_engine-socks5.test

@@ -6,4 +6,5 @@ set -euo pipefail
 # The SOCKS5 handshake framing and credential split, driven against scripted
 # server replies (frame draining, oversize rejects, RFC 1929 fields).
 
-httrack -O /dev/null '-#test=socks5' | grep -q "socks5 self-test OK"
+out=$(httrack -O /dev/null '-#test=socks5')
+grep -q "socks5 self-test OK" <<<"$out"

tests/01_engine-status.test

@@ -4,4 +4,5 @@
 set -euo pipefail
 
 # HTTP status -> reason phrase, including the modern 429/451 (#453).
-httrack -O /dev/null -#test=status run | grep -q "status self-test OK"
+out=$(httrack -O /dev/null -#test=status run)
+grep -q "status self-test OK" <<<"$out"

tests/01_engine-stripquery.test

@@ -5,4 +5,5 @@ set -euo pipefail
 
 # --strip-query: pattern-scoped query-key stripping for dedup. All assertions
 # live in the engine self-test (hts_query_strip_keys + fil_normalized_filtered).
-httrack -O /dev/null -#test=stripquery | grep -q "strip-query self-test OK"
+out=$(httrack -O /dev/null -#test=stripquery)
+grep -q "strip-query self-test OK" <<<"$out"

tests/01_engine-structcheck.test

@@ -6,7 +6,7 @@
 set -euo pipefail
 
 dir=$(mktemp -d)
-trap 'rm -rf "$dir"' EXIT
+trap 'set +e; rm -rf "$dir"' EXIT
 
 httrack -O /dev/null -#test=structcheck "$dir" |
     grep -q "structcheck self-test OK"

tests/01_engine-threadwait.test

@@ -3,25 +3,13 @@
 
 set -euo pipefail
 
-tmpdir=$(mktemp -d "${TMPDIR:-/tmp}/httrack_threadwait_st.XXXXXX") || exit 1
-trap 'rm -rf "$tmpdir"' EXIT HUP INT QUIT PIPE TERM
+testdir=$(cd "$(dirname "$0")" && pwd)
+# shellcheck source=tests/testlib.sh
+. "${testdir}/testlib.sh"
 
-# No pipe into grep: SIGPIPE would mask a failing exit status.
-expect_ok() {
-    local label="$1" out
-    shift
-    out=$("$@" 2>&1) || {
-        echo "FAIL: ${label} exited non-zero: ${out}"
-        exit 1
-    }
-    case "$out" in
-    *"${label}: OK"*) ;;
-    *)
-        echo "FAIL: ${out}"
-        exit 1
-        ;;
-    esac
-}
+tmpdir=$(mktemp -d "${TMPDIR:-/tmp}/httrack_threadwait_st.XXXXXX") || exit 1
+trap 'set +e; rm -rf "$tmpdir"' EXIT
+trap 'rm -rf "$tmpdir"' HUP INT QUIT PIPE TERM
 
 # A thread is outstanding from the moment hts_newthread() returns, so a wait
 # that follows the spawn joins it, and wait_n(n) still leaves n behind (#747).

tests/01_engine-topindex.test

@@ -6,7 +6,7 @@ set -euo pipefail
 # hts_buildtopindex takes a system-charset path but verif_backblue below it
 # expects utf-8, mangling a non-ASCII project dir on Windows (#216, #217).
 dir=$(mktemp -d)
-trap 'rm -rf "$dir"' EXIT
+trap 'set +e; rm -rf "$dir"' EXIT
 
 httrack -O /dev/null -#test=topindex "$dir" run |
     grep -q "topindex self-test OK"

tests/01_engine-unescape-bounds.test

@@ -4,4 +4,5 @@
 set -euo pipefail
 
 # Entity/URL unescapers reserve one byte for the trailing NUL (no 1-byte OOB).
-httrack -O /dev/null -#test=unescape-bounds run | grep -q "unescape-bounds self-test OK"
+out=$(httrack -O /dev/null -#test=unescape-bounds run)
+grep -q "unescape-bounds self-test OK" <<<"$out"

tests/01_engine-urlhack.test

@@ -5,4 +5,5 @@ set -euo pipefail
 
 # -%u url-hack split (#271): www / // / query-order dedup toggle independently.
 # All assertions live in the engine self-test (hash compare flag resolution).
-httrack -O /dev/null -#test=urlhack run | grep -q "urlhack self-test OK"
+out=$(httrack -O /dev/null -#test=urlhack run)
+grep -q "urlhack self-test OK" <<<"$out"

tests/01_engine-useragent.test

@@ -4,4 +4,5 @@
 set -euo pipefail
 
 # Default User-Agent (#449): honest HTTrack token, no Windows 98 relic.
-httrack -O /dev/null -#test=useragent run | grep -q "useragent self-test OK"
+out=$(httrack -O /dev/null -#test=useragent run)
+grep -q "useragent self-test OK" <<<"$out"

tests/01_engine-warc-surt.test

@@ -5,4 +5,5 @@ set -euo pipefail
 
 # SURT canonicalization of the CDXJ sort key (--warc-cdx). Pure string work,
 # so it runs under the MSan-instrumented 01_engine glob.
-httrack -O /dev/null -#test=warc-surt | grep -q "warc-surt: OK"
+out=$(httrack -O /dev/null -#test=warc-surt)
+grep -q "warc-surt: OK" <<<"$out"

tests/01_zlib-acceptencoding.test

@@ -5,7 +5,7 @@ set -euo pipefail
 
 # Accept-Encoding (#450): advertise gzip+deflate; decode gzip/zlib/raw-deflate.
 dir=$(mktemp -d)
-trap 'rm -rf "$dir"' EXIT
+trap 'set +e; rm -rf "$dir"' EXIT
 
 httrack -O /dev/null -#test=acceptencoding "$dir" run |
     grep -q "acceptencoding self-test OK"

tests/01_zlib-cache-corrupt.test

@@ -7,7 +7,7 @@
 set -eu
 
 dir=$(mktemp -d)
-trap 'rm -rf "$dir"' EXIT
+trap 'set +e; rm -rf "$dir"' EXIT
 
 # the smashed-header case logs expected "Corrupted cache entry" warnings on
 # stdout; the verdict is the last line

tests/01_zlib-cache-golden.test

@@ -27,7 +27,7 @@ test -e "$fixture/hts-cache/new.zip" || {
 }
 
 dir=$(mktemp -d)
-trap 'rm -rf "$dir"' EXIT
+trap 'set +e; rm -rf "$dir"' EXIT
 
 # Read against a private copy so the source tree is never touched (a read
 # session does not write, but copying keeps the test hermetic). Create the dir

tests/01_zlib-cache-legacy.test

@@ -6,7 +6,7 @@
 set -eu
 
 dir=$(mktemp -d)
-trap 'rm -rf "$dir"' EXIT
+trap 'set +e; rm -rf "$dir"' EXIT
 
 # the refusal errors land on stdout (no log file); pin them and the verdict
 out=$(httrack -#test=cache-legacy "$dir" 2>/dev/null)

tests/01_zlib-cache-writefail.test

@@ -1,8 +1,6 @@
 #!/bin/bash
 #
-# Keep this POSIX-portable: the harness runs it via $(BASH), which is a plain
-# POSIX /bin/sh on some platforms (e.g. macOS), so avoid bashisms and GNU-only
-# tool flags despite the #!/bin/bash above.
+# Stick to POSIX tool flags: macOS ships BSD grep/sed, not the GNU ones.
 
 # Cache write-failure policy (-#test=cache-writefail <dir>). #174/#219: disk
 # full or a failure streak aborts cleanly; an isolated failure or an oversized
@@ -11,19 +9,19 @@
 set -eu
 
 dir=$(mktemp -d)
-trap 'rm -rf "$dir"' EXIT
+trap 'set +e; rm -rf "$dir"' EXIT
 
 out=$(httrack -#test=cache-writefail "$dir")
 
 # Match the exact success line (error logs also go to stdout); a renamed/removed
 # test prints the registry to stderr, which exits non-zero but never prints this.
-printf '%s\n' "$out" | grep -qx "cache-writefail: OK" || {
+grep -qx "cache-writefail: OK" <<<"$out" || {
     echo "expected 'cache-writefail: OK', got: $out" >&2
     exit 1
 }
 
 # A skipped entry must be warned about with its URL.
-printf '%s\n' "$out" | grep -q "entry not cached: example.com/" || {
+grep -q "entry not cached: example.com/" <<<"$out" || {
     echo "expected a URL-bearing skip warning" >&2
     exit 1
 }

tests/01_zlib-cache.test

@@ -18,7 +18,7 @@
 set -eu
 
 dir=$(mktemp -d)
-trap 'rm -rf "$dir"' EXIT
+trap 'set +e; rm -rf "$dir"' EXIT
 
 # The working directory is a required argument; without it the test prints a
 # usage line to stderr and returns non-zero.

tests/01_zlib-contentcodings.test

@@ -5,7 +5,7 @@ set -euo pipefail
 
 # brotli/zstd decode, unknown codings, and the decoded-size budget.
 dir=$(mktemp -d)
-trap 'rm -rf "$dir"' EXIT
+trap 'set +e; rm -rf "$dir"' EXIT
 
 httrack -O /dev/null -#test=contentcodings "$dir" run |
     grep -q "contentcodings self-test OK"

tests/01_zlib-repair-shift.test

@@ -1,8 +1,6 @@
 #!/bin/bash
 #
-# Keep this POSIX-portable: the harness runs it via $(BASH), which is a plain
-# POSIX /bin/sh on some platforms (e.g. macOS), so avoid bashisms and GNU-only
-# tool flags despite the #!/bin/bash above.
+# Stick to POSIX tool flags: macOS ships BSD grep/sed, not the GNU ones.
 
 # unzRepair header read must not overflow a signed shift (-#test=zip-repair-shift
 # <dir>). A damaged local file header whose CRC high word has bit 15 set made
@@ -11,11 +9,11 @@
 set -eu
 
 dir=$(mktemp -d)
-trap 'rm -rf "$dir"' EXIT
+trap 'set +e; rm -rf "$dir"' EXIT
 
 out=$(httrack -#test=zip-repair-shift "$dir")
 
-printf '%s\n' "$out" | grep -qx "zip-repair-shift: OK (recovered 1 entry)" || {
+grep -qx "zip-repair-shift: OK (recovered 1 entry)" <<<"$out" || {
     echo "expected 'zip-repair-shift: OK (recovered 1 entry)', got: $out" >&2
     exit 1
 }

tests/01_zlib-savename-cached.test

@@ -10,7 +10,7 @@ set -euo pipefail
 httrack_bin=$(cd "$(dirname "$(command -v httrack)")" && pwd)/httrack
 
 scratch=$(mktemp -d)
-trap 'rm -rf "$scratch"' EXIT
+trap 'set +e; rm -rf "$scratch"' EXIT
 cd "$scratch"
 
 name() {

tests/01_zlib-warc-cdx.test

@@ -9,7 +9,7 @@ set -euo pipefail
 httrack_bin=$(cd "$(dirname "$(command -v httrack)")" && pwd)/httrack
 
 scratch=$(mktemp -d)
-trap 'rm -rf "$scratch"' EXIT
+trap 'set +e; rm -rf "$scratch"' EXIT
 
 out=$("$httrack_bin" -O /dev/null -#test=warc-cdx "$scratch/")
 echo "$out"

tests/01_zlib-warc-wacz.test

@@ -10,13 +10,14 @@ set -euo pipefail
 
 httrack_bin=$(cd "$(dirname "$(command -v httrack)")" && pwd)/httrack
 
-if ! "$httrack_bin" -#test 2>&1 | grep -q '^  warc-wacz'; then
+registry=$("$httrack_bin" -#test 2>&1 || true)
+if ! grep -q '^  warc-wacz' <<<"$registry"; then
     echo "warc-wacz self-test unavailable (build without OpenSSL); skipping"
     exit 77
 fi
 
 scratch=$(mktemp -d)
-trap 'rm -rf "$scratch"' EXIT
+trap 'set +e; rm -rf "$scratch"' EXIT
 
 out=$("$httrack_bin" -O /dev/null -#test=warc-wacz "$scratch/")
 echo "$out"

tests/01_zlib-warc.test

@@ -10,7 +10,7 @@ set -euo pipefail
 httrack_bin=$(cd "$(dirname "$(command -v httrack)")" && pwd)/httrack
 
 scratch=$(mktemp -d)
-trap 'rm -rf "$scratch"' EXIT
+trap 'set +e; rm -rf "$scratch"' EXIT
 
 for t in warc warc-trunc warc-ftp warc-rotate warc-verbatim; do
     out=$("$httrack_bin" -O /dev/null "-#test=$t" "$scratch/")

tests/02_manpage-regen.test

@@ -29,7 +29,7 @@ command -v httrack >/dev/null 2>&1 || {
 tmp=$(mktemp) || exit 1
 committed_clean=$(mktemp) || exit 1
 generated_clean=$(mktemp) || exit 1
-trap 'rm -f "$tmp" "$committed_clean" "$generated_clean"' EXIT
+trap 'set +e; rm -f "$tmp" "$committed_clean" "$generated_clean"' EXIT
 
 README="$top_srcdir/README" bash "$gen" httrack >"$tmp" 2>/dev/null || {
     echo "makeman.sh failed" >&2

tests/02_update-cache.test

@@ -14,7 +14,7 @@ set -euo pipefail
 
 site=$(mktemp -d)
 out=$(mktemp -d)
-trap 'rm -rf "$site" "$out"' EXIT
+trap 'set +e; rm -rf "$site" "$out"' EXIT
 
 cat >"$site/index.html" <<EOF
 <a href="a.html">a</a> <a href="sub/b.html">b</a>

tests/100_local-purge-longpath.test

@@ -0,0 +1,111 @@
+#!/bin/bash
+#
+# The end-of-mirror purge read old.lst with linput(fp, line, 1000), which caps a
+# chunk at 999 bytes. filenote() writes "[<save path>]", so a 998-byte save path
+# makes a 1000-byte line that comes back as 999 bytes plus a one-byte "]" tail.
+# For that tail `line + 1` is empty, and with no -O so is path_html, so the purge
+# indexed file[-1] (#770). Needs no -O, hence not local-crawl.sh.
+#
+# The OOB write lands in stack padding, so only the sanitized CI leg fails on
+# unfixed code; the length assertion below is what keeps this from passing
+# vacuously if the save path ever stops landing on the chunk boundary.
+
+set -euo pipefail
+
+: "${top_srcdir:=..}"
+
+# shellcheck source=tests/testlib.sh
+. "$top_srcdir/tests/testlib.sh"
+
+# python3 is required; mirror check-network.sh's skip-with-77 convention.
+python=$(find_python) || ! echo "python3 not found; skipping" >&2 || exit 77
+
+# Resolve httrack now: the harness prepends a RELATIVE dir to PATH, so the cd
+# below would otherwise silently fall through to an installed copy.
+httrack_bin=$(command -v httrack)
+test -n "$httrack_bin" || {
+    echo "httrack not on PATH" >&2
+    exit 1
+}
+httrack_bin=$(cd "$(dirname "$httrack_bin")" && pwd)/$(basename "$httrack_bin")
+
+work=$(mktemp -d)
+trap 'set +e; kill -9 "${spid:-}" 2>/dev/null || true; rm -rf "$work"' EXIT
+
+mkdir -p "$work/root" "$work/proj"
+
+"$python" "$top_srcdir/tests/local-server.py" --root "$work/root" \
+    >"$work/server.out" 2>"$work/server.err" &
+spid=$!
+
+port=
+for _ in $(seq 1 100); do
+    port=$(sed -n 's/^PORT \([0-9]*\)$/\1/p' "$work/server.out" 2>/dev/null || true)
+    test -n "$port" && break
+    sleep 0.1
+done
+test -n "$port" || {
+    echo "local-server.py did not announce a port" >&2
+    exit 1
+}
+
+# Save path is "127.0.0.1_<port>/" + the URL path; target 998 bytes total.
+prefix="127.0.0.1_${port}/"
+need=$((998 - ${#prefix}))
+
+# macOS caps PATH_MAX at 1024, so neither the docroot nor the mirror can hold a
+# 998-byte path, and httrack's own HTS_MAX_PATH_LEN clamps below it too. The
+# trigger is simply not reachable there.
+pathmax=$(getconf PATH_MAX / 2>/dev/null || echo 4096)
+test "$pathmax" -ge $((need + ${#work} + 128)) || {
+    echo "PATH_MAX $pathmax too small for a $need-byte path; skipping" >&2
+    exit 77
+}
+
+# Same on Win32, where MAX_PATH clamps the save path; getconf answers for the
+# MSYS emulation, not the Win32 API httrack calls, so it cannot see this.
+case "$(uname -s)" in
+MINGW* | MSYS* | CYGWIN*)
+    echo "Win32 MAX_PATH cannot hold a $need-byte save path; skipping" >&2
+    exit 77
+    ;;
+esac
+
+urlpath=""
+while test $((need - ${#urlpath})) -gt 60; do
+    urlpath="${urlpath}$(printf 'd%02d' ${#urlpath})$(printf 'a%.0s' $(seq 1 46))/"
+done
+urlpath="${urlpath}$(printf 'f%.0s' $(seq 1 $((need - ${#urlpath} - 5)))).html"
+test ${#urlpath} -eq "$need"
+
+mkdir -p "$work/root/$(dirname "$urlpath")"
+printf '<html><body>leaf</body></html>\n' >"$work/root/$urlpath"
+printf '<html><body><a href="/%s">x</a></body></html>\n' "$urlpath" \
+    >"$work/root/index.html"
+
+cd "$work/proj" # no -O: opt->path_html stays empty
+
+"$httrack_bin" "http://127.0.0.1:$port/" -q -%v0 -s0 -r3 >"$work/crawl1.log" 2>&1 || true
+
+lst=$work/proj/hts-cache/new.lst
+test -f "$lst" || {
+    echo "pass 1 produced no new.lst" >&2
+    exit 1
+}
+# Arms the test: without a line of exactly 1000 bytes linput() never splits and
+# the purge never sees a one-byte tail.
+awk 'length == 1000 { found = 1 } END { exit !found }' "$lst" || {
+    echo "no 1000-byte line in new.lst; the chunk split is not exercised" >&2
+    awk '{ print length }' "$lst" | sort -n | tail -3 >&2
+    echo "--- urlpath len ${#urlpath}, prefix $prefix" >&2
+    tail -20 "$work/crawl1.log" >&2
+    exit 1
+}
+
+# Pass 2 renames new.lst to old.lst and runs it through the purge loop.
+"$httrack_bin" "http://127.0.0.1:$port/" -q -%v0 -s0 -r3 >"$work/crawl2.log" 2>&1
+
+test -s "$work/proj/$prefix$urlpath" || {
+    echo "the mirrored leaf did not survive the purge" >&2
+    exit 1
+}

tests/102_local-ftp-refetch.test

@@ -0,0 +1,166 @@
+#!/bin/bash
+#
+# An FTP re-fetch used to truncate the mirror before the transfer, so a failed
+# one destroyed the previous copy (#771). keep.bin is cut short and empty.bin
+# gets nothing; both must keep their old bytes. stay.bin takes the same path and
+# completes, so a fix that merely stopped writing would fail here.
+
+set -euo pipefail
+
+: "${top_srcdir:=..}"
+testdir=$(cd "$(dirname "$0")" && pwd)
+# shellcheck source=tests/testlib.sh
+. "${testdir}/testlib.sh"
+
+python=$(find_python) || ! echo "python3 not found; skipping" >&2 || exit 77
+command -v httrack >/dev/null || {
+    echo "could not find httrack" >&2
+    exit 1
+}
+
+server=$(nativepath "${testdir}/ftp-server.py")
+tmpdir=$(mktemp -d "${TMPDIR:-/tmp}/httrack_ftp.XXXXXX")
+serverpid=
+cleanup() {
+    stop_server "$serverpid"
+    rm -rf "$tmpdir"
+}
+trap 'set +e; cleanup' EXIT
+trap cleanup HUP INT QUIT PIPE TERM
+
+root="${tmpdir}/root"
+out="${tmpdir}/crawl"
+mode="${tmpdir}/mode"
+report="${out}/hts-changes.json"
+mkdir -p "$root" "$out"
+
+# The two generations differ in length, or a re-fetch that resumed at EOF
+# instead of truncating would leave the same bytes and pass for the wrong reason.
+write_bodies() {
+    local gen="$1" fill="$2" name
+    for name in keep empty stay; do
+        "$python" -c 'import sys; sys.stdout.buffer.write(
+            ("%s-FTP-%s " % (sys.argv[1].upper(), sys.argv[2])).encode()
+            + sys.argv[2][-1].encode() * int(sys.argv[3]))' "$name" "$gen" "$fill" \
+            >"${root}/${name}.bin"
+    done
+}
+write_bodies V1 4096
+: >"$mode"
+
+serverlog="${tmpdir}/server.out"
+"$python" "$server" --root "$(nativepath "$root")" \
+    --mode-file "$(nativepath "$mode")" >"$serverlog" 2>&1 &
+serverpid=$!
+port=
+for _ in $(seq 1 300); do
+    line=$(grep -m1 '^PORT ' "$serverlog" 2>/dev/null) && port="${line#PORT }" && break
+    kill -0 "$serverpid" 2>/dev/null || {
+        echo "ftp server exited early: $(cat "$serverlog")" >&2
+        exit 1
+    }
+    sleep 0.1
+done
+test -n "$port" || {
+    echo "could not discover ftp server port: $(cat "$serverlog")" >&2
+    exit 1
+}
+host="127.0.0.1_${port}"
+urls=()
+for name in keep empty stay; do
+    urls+=("ftp://127.0.0.1:${port}/${name}.bin")
+done
+# -c1: a parallel FTP crawl loses whole transfers to a separate, older bug in
+# the backlog slot swap (#797), which would flake this test on a loaded runner.
+common=(--quiet --disable-security-limits --robots=0 --timeout=20 --max-time=120
+    --retries=1 -c1 --changes)
+
+fail() {
+    echo "FAIL: $*" >&2
+    test ! -f "$report" || cat "$report" >&2
+    exit 1
+}
+ok() { echo "OK: $*"; }
+size_of() { wc -c <"$1" | tr -d '[:space:]'; }
+# Files listed under a report bucket, one "file:size" per line.
+listed() {
+    "$python" - "$report" "$1" <<'EOF' | tr -d '\r'
+import json
+import sys
+
+with open(sys.argv[1], encoding="utf-8") as fp:
+    report = json.load(fp)
+for entry in report[sys.argv[2]]:
+    print("%s:%s" % (entry["file"], entry.get("size", "none")))
+EOF
+}
+
+# --- pass 1: a healthy mirror ------------------------------------------------
+# Bounded like every local-crawl.sh pass: a wedged crawl must fail the test, not
+# hang the job until CI cancels it and discards the log (#796).
+run_with_timeout 300 httrack "${urls[@]}" -O "$out" "${common[@]}" \
+    >"${tmpdir}/log1" 2>&1
+for name in keep empty stay; do
+    test -s "${out}/${host}/${name}.bin" || fail "pass 1 did not mirror ${name}.bin"
+done
+mkdir "${tmpdir}/snap"
+cp "${out}/${host}"/*.bin "${tmpdir}/snap/"
+ok "pass 1 mirrored three files"
+
+# --- pass 2: the same three re-fetched, two of them failing -------------------
+# norest throughout: an accepted REST sends the client down the append path,
+# which is not the one that truncates.
+write_bodies V2 6000
+cat >"$mode" <<'EOF'
+/keep.bin truncate norest
+/empty.bin empty norest
+/stay.bin norest
+EOF
+run_with_timeout 300 httrack "${urls[@]}" -O "$out" "${common[@]}" --update \
+    >"${tmpdir}/log2" 2>&1
+
+# Both failures have to be the transfer dying mid-body: a connect or lookup
+# failure never opens the file, and everything below would pass vacuously.
+for name in keep empty; do
+    grep -aqE "Error:.*\"FTP file incomplete\".*${name}\.bin" "${out}/hts-log.txt" ||
+        fail "${name}.bin did not fail during the transfer"
+done
+ok "both re-fetches reached the body and failed there"
+
+for name in keep empty; do
+    cmp -s "${out}/${host}/${name}.bin" "${tmpdir}/snap/${name}.bin" ||
+        fail "${name}.bin differs from the copy pass 1 left ($(size_of \
+            "${out}/${host}/${name}.bin") bytes now)"
+done
+ok "a failed FTP transfer left the previously mirrored bytes alone"
+
+grep -aq "FTP-V2 " "${out}/${host}/stay.bin" ||
+    fail "stay.bin was not refreshed; the re-fetch writes nothing at all now"
+ok "a successful FTP re-fetch still replaces the file"
+
+leftover=$(find "${out}/${host}" -name '*.bak')
+test -z "$leftover" || fail "backup left behind: ${leftover}"
+ok "no backup temporary survived the pass"
+
+# --purge-old is on by default: a kept file the run never replaced must still be
+# in new.lst, or it is deleted as gone (#746).
+for name in keep empty stay; do
+    test -f "${out}/${host}/${name}.bin" || fail "${name}.bin was purged"
+done
+ok "the kept copies survived the update purge"
+
+# --- the change report is the mirror's own account of the pass ----------------
+test -s "$report" || fail "pass 2 wrote no ${report}"
+test -z "$(listed gone)" || fail "the report calls something gone: $(listed gone)"
+unchanged=$(listed unchanged)
+changed=$(listed changed)
+for name in keep empty; do
+    grep -qx "${host}/${name}.bin:$(size_of "${tmpdir}/snap/${name}.bin")" <<<"$unchanged" ||
+        fail "${name}.bin is not reported unchanged at its previous size"
+    if grep -q "^${host}/${name}.bin:" <<<"$changed"; then
+        fail "${name}.bin is reported changed as well"
+    fi
+done
+grep -qx "${host}/stay.bin:$(size_of "${out}/${host}/stay.bin")" <<<"$changed" ||
+    fail "stay.bin is not reported changed"
+ok "the change report calls the kept files unchanged and the refreshed one changed"

tests/103_teardown-status.test

@@ -0,0 +1,81 @@
+#!/bin/bash
+#
+# Issue #773: a test must fail only when an assertion fails. Under "set -e" a
+# failing command in an EXIT trap becomes the script's exit status, so a
+# teardown hiccup turned a test whose assertions all passed into a red CI leg.
+
+set -euo pipefail
+
+: "${top_srcdir:=..}"
+
+tmp=$(mktemp -d)
+trap 'set +e; rm -rf "$tmp"' EXIT
+
+fail() {
+    echo "FAIL: $1" >&2
+    exit 1
+}
+
+# run <trap-body> <script-body>: exit status and stderr of a subject script.
+run() {
+    {
+        echo "set -euo pipefail"
+        # printf, so the scanner below does not read this as a trap of our own
+        printf 'trap %s EXIT\n' "$1"
+        echo "$2"
+    } >"$tmp/subject"
+    rc=0
+    err=$(bash "$tmp/subject" 2>&1 >/dev/null) || rc=$?
+}
+
+# 1. the shape in the tree: teardown fails, every assertion passed -> pass
+run "'set +e; false'" "true"
+test "$rc" -eq 0 || fail "guarded teardown failure exited $rc, want 0"
+
+# 2. teeth for case 1: unguarded, the same teardown is what went red
+run "'false'" "true"
+test "$rc" -eq 1 || fail "unguarded teardown failure exited $rc, want 1"
+
+# 3. the guard must not swallow a real failure, nor a skip
+run "'set +e; false'" "exit 1"
+test "$rc" -eq 1 || fail "assertion failure exited $rc, want 1"
+run "'set +e; false'" "exit 77"
+test "$rc" -eq 77 || fail "skip exited $rc, want 77"
+
+# 4. not failing must not mean going quiet: teardown still reports why
+run "'set +e; rm /nonexistent-teardown-probe'" "true"
+test "$rc" -eq 0 || fail "guarded teardown failure exited $rc, want 0"
+case "$err" in
+*nonexistent-teardown-probe*) ;;
+*) fail "teardown error was silenced (stderr: '$err')" ;;
+esac
+echo "OK: teardown cannot decide the verdict, and still reports"
+
+# 5. no test may reintroduce the shape case 2 pins. Two spellings neutralise
+# errexit for teardown: "set +e" first, or "|| true" over the whole body.
+scanned=0
+for f in "$top_srcdir"/tests/*.test "$top_srcdir"/tests/*.sh; do
+    test -r "$f" || continue
+    scanned=$((scanned + 1))
+done
+# an unexpanded glob would report no offender having read nothing
+test "$scanned" -ge 50 || fail "scanned $scanned scripts in $top_srcdir/tests, want the whole suite"
+
+bad=$(awk '
+    FNR == 1 { errexit = 0 }
+    /^[[:space:]]*set[[:space:]]+(-[a-z]*e|-o[[:space:]]+errexit)/ { errexit = 1 }
+    !errexit { next }
+    !/^[[:space:]]*trap[[:space:]]+.*[[:space:]]EXIT([[:space:]]|;|$)/ { next }
+    {
+        guarded = /^[[:space:]]*trap[[:space:]]+.set \+e; / || /\|\|[[:space:]]+true.[[:space:]]+EXIT/
+        if (!guarded)
+            print FILENAME ":" FNR " unguarded"
+        # "set +e" on a trap shared with a signal leaves errexit off for the
+        # rest of the run, so a torn-down test could still report success
+        else if (/^[[:space:]]*trap[[:space:]]+.set \+e; / && /[[:space:]]EXIT[[:space:]]+[A-Z]/)
+            print FILENAME ":" FNR " set +e shared with a signal trap"
+    }
+' "$top_srcdir"/tests/*.test "$top_srcdir"/tests/*.sh)
+test -z "$bad" || fail "EXIT trap can decide the verdict:
+$bad"
+echo "OK: every EXIT trap under set -e runs teardown with errexit off"

tests/104_engine-warc-longurl.test

@@ -0,0 +1,13 @@
+#!/bin/bash
+#
+# A URL past the header-format buffer must still produce a record: the archive
+# used to lose it whole, with no error and an exit status of 0 (#785).
+
+set -e
+
+: "${top_srcdir:=..}"
+
+tmp=$(mktemp -d "${TMPDIR:-/tmp}/httrack_longurl.XXXXXX")
+trap 'set +e; rm -rf "$tmp"' EXIT
+
+httrack -O "$tmp/out" "-#test=warc-longurl" "$tmp"

tests/105_suite-timeout.test

@@ -0,0 +1,141 @@
+#!/bin/bash
+#
+# The harness timeout (tests/test-timeout.sh) must name the test it killed, say
+# what was still running, and exit 124 -- otherwise a wedge only ever shows up as
+# a cancelled CI step, which keeps no log and no artifact.
+
+set -eu
+
+testdir=$(cd "$(dirname "$0")" && pwd)
+# shellcheck source=tests/testlib.sh
+. "${testdir}/testlib.sh"
+
+driver="${testdir}/test-timeout.sh"
+test -r "$driver" || {
+    echo "no test-timeout.sh next to $0" >&2
+    exit 1
+}
+
+fail() {
+    echo "FAIL: $*" >&2
+    test -z "${out:-}" || sed 's/^/  | /' <"$out" >&2
+    exit 1
+}
+
+tmp=$(mktemp -d "${TMPDIR:-/tmp}/httrack_sutmo.XXXXXX") || exit 1
+trap 'set +e; rm -rf "$tmp"' EXIT
+trap 'rm -rf "$tmp"' HUP INT QUIT PIPE TERM
+out="$tmp/out"
+
+# --- a hanging test is killed, named, and reported 124 ----------------------
+cat >"$tmp/90_wedged.test" <<'EOF'
+echo "marker: the wedged test started"
+sleep 300
+EOF
+
+start=$SECONDS
+rc=0
+HTTRACK_TEST_TIMEOUT=5 bash "$driver" "$tmp/90_wedged.test" >"$out" 2>&1 || rc=$?
+elapsed=$((SECONDS - start))
+
+test "$rc" -eq 124 || fail "wedged test reported $rc, want 124"
+# Never before the budget, or a slow-but-healthy test would be killed too.
+test "$elapsed" -ge 5 || fail "the guard fired early (${elapsed}s of a 5s budget)"
+test "$elapsed" -lt 30 || fail "the guard fired late (${elapsed}s)"
+grep -q 'marker: the wedged test started' "$out" || fail "the test's own output was lost"
+# The header, not a bare name: the process list quotes the test's path too, so a
+# wrapper that named nothing would still match that.
+grep -q '^===== TIMEOUT: 90_wedged.test exceeded' "$out" ||
+    fail "the diagnostics do not name the test"
+grep -q "own process tree" "$out" || fail "no process list in the diagnostics"
+
+# The budget is read, not hard-coded: well under it, the same shape survives.
+printf 'sleep 3\necho "slow but healthy"\n' >"$tmp/92_slow.test"
+rc=0
+HTTRACK_TEST_TIMEOUT=45 bash "$driver" "$tmp/92_slow.test" >"$out" 2>&1 || rc=$?
+test "$rc" -eq 0 || fail "a healthy 3s test under a 45s budget reported $rc"
+grep -q 'slow but healthy' "$out" || fail "healthy test output lost"
+! grep -q 'TIMEOUT' "$out" || fail "the guard fired on a healthy test"
+
+# The killed tree must really be gone, or the next test inherits its ports.
+sleep 1
+! grep -q "$tmp/90_wedged.test" <<<"$(ps -A -o args 2>/dev/null)" ||
+    fail "the wedged test survived the guard"
+
+# --- exit status and output of a healthy test pass straight through ----------
+# 77 is automake's SKIP and 99 its hard error, so both have to survive the wrapper.
+for want in 0 1 77 99; do
+    printf 'echo "ran with %s"\nexit %s\n' "$want" "$want" >"$tmp/91_plain.test"
+    rc=0
+    HTTRACK_TEST_TIMEOUT=60 bash "$driver" "$tmp/91_plain.test" >"$out" 2>&1 || rc=$?
+    test "$rc" -eq "$want" || fail "exit $want came back as $rc"
+    grep -q "ran with $want" "$out" || fail "output lost for exit $want"
+    ! grep -q 'TIMEOUT' "$out" || fail "the guard fired on a test that exited at once"
+done
+
+# A budget of 0 disables the guard: the test still runs, and is not killed. Its
+# own file, so the assertion cannot ride on whatever the loop above left behind.
+printf 'echo "guard off"\nexit 3\n' >"$tmp/93_off.test"
+rc=0
+HTTRACK_TEST_TIMEOUT=0 bash "$driver" "$tmp/93_off.test" >"$out" 2>&1 || rc=$?
+test "$rc" -eq 3 || fail "disabled guard changed the exit status ($rc)"
+grep -q 'guard off' "$out" || fail "output lost with the guard disabled"
+
+# --- a wedged crawl yields a symbolized engine stack ------------------------
+# The whole point of the dump: name the frame the engine is stuck in. Windows has
+# neither half (MSYS signals do not reach a native httrack.exe, and that build has
+# no backtrace()), so only assert it where the machinery exists.
+if is_windows; then
+    echo "suite timeout OK (no stack capture on Windows)"
+    exit 0
+fi
+command -v httrack >/dev/null || {
+    echo "SKIP: no httrack on PATH for the stack half" >&2
+    exit 77
+}
+
+# /watchdog/stall never answers, so the crawl wedges for real. CRAWL_DEADLINE is
+# raised past our budget so the guard under test is what fires, not local-crawl's.
+cat >"$tmp/92_stalled.test" <<EOF
+CRAWL_DEADLINE=600 bash "${testdir}/local-crawl.sh" --errors 0 \\
+    httrack 'BASEURL/watchdog/stall'
+EOF
+
+rc=0
+HTTRACK_TEST_TIMEOUT=20 bash "$driver" "$tmp/92_stalled.test" >"$out" 2>&1 || rc=$?
+
+if grep -qE 'python3 not found|could not discover server port' "$out"; then
+    echo "SKIP: local crawl prerequisites missing" >&2
+    exit 77
+fi
+test "$rc" -eq 124 || fail "stalled crawl reported $rc, want 124"
+
+if grep -q 'No stack trace available on this OS' "$out"; then
+    echo "suite timeout OK (no backtrace() on this platform)"
+    exit 0
+fi
+
+# Each platform's mechanism has its own marker, and the marker is what proves the
+# whole chain connected up rather than the dump merely running.
+case "$(uname -s)" in
+Linux)
+    # sig_fatal writes to the engine's own stderr, so this reaching our log also
+    # proves the crawl-log salvage worked.
+    grep -q '^Caught signal ' "$out" || fail "no engine backtrace was salvaged"
+    ;;
+Darwin)
+    grep -q '^Call graph:' "$out" || fail "sample(1) produced no call graph"
+    ;;
+*)
+    grep -q 'no stack mechanism known' "$out" ||
+        fail "unknown platform reported neither a stack nor its absence"
+    echo "suite timeout OK (no stack mechanism on $(uname -s))"
+    exit 0
+    ;;
+esac
+# A stalled crawl is necessarily inside httpmirror, so these frames must appear.
+# Matching "httrack" alone would pass on the process list above.
+grep -qE '\b(back_wait|httpmirror|hts_main_internal)\b' "$out" ||
+    fail "the stack names no engine frame"
+
+echo "suite timeout OK (named the test, dumped a stack, exited 124)"

tests/110_local-ftp-parallel.test

@@ -0,0 +1,98 @@
+#!/bin/bash
+#
+# A completed FTP transfer used to end as a 0-byte file when its ready backlog
+# slot was swapped to the on-disk table (#797): the FTP worker writes url_sav
+# itself and leaves no in-memory body, and the swap round-trip zeroed the slot's
+# size, so the link writer then created an empty file over the bytes.
+
+set -euo pipefail
+
+: "${top_srcdir:=..}"
+testdir=$(cd "$(dirname "$0")" && pwd)
+# shellcheck source=tests/testlib.sh
+. "${testdir}/testlib.sh"
+
+python=$(find_python) || ! echo "python3 not found; skipping" >&2 || exit 77
+command -v httrack >/dev/null || {
+    echo "could not find httrack" >&2
+    exit 1
+}
+
+server=$(nativepath "${testdir}/ftp-server.py")
+tmpdir=$(mktemp -d "${TMPDIR:-/tmp}/httrack_ftp.XXXXXX")
+serverpid=
+cleanup() {
+    stop_server "$serverpid"
+    rm -rf "$tmpdir"
+}
+trap 'set +e; cleanup' EXIT
+trap cleanup HUP INT QUIT PIPE TERM
+
+root="${tmpdir}/root"
+out="${tmpdir}/crawl"
+mkdir -p "$root" "$out"
+
+fail() {
+    echo "FAIL: $*" >&2
+    exit 1
+}
+ok() { echo "OK: $*"; }
+size_of() { wc -c <"$1" | tr -d '[:space:]'; }
+
+# Distinct bodies and lengths, so a mirror that mixed two of them up cannot
+# compare equal.
+names=""
+for i in 1 2 3 4 5 6 7 8 9 10 11 12; do
+    names="${names} f${i}"
+    "$python" -c 'import sys; sys.stdout.buffer.write(
+        ("BODY-%s " % sys.argv[1]).encode() + sys.argv[1].encode() * (400 * int(sys.argv[1])))' \
+        "$i" >"${root}/f${i}.bin"
+done
+
+serverlog="${tmpdir}/server.out"
+"$python" "$server" --root "$(nativepath "$root")" >"$serverlog" 2>&1 &
+serverpid=$!
+port=
+for _ in $(seq 1 300); do
+    line=$(grep -m1 '^PORT ' "$serverlog" 2>/dev/null) && port="${line#PORT }" && break
+    kill -0 "$serverpid" 2>/dev/null || {
+        echo "ftp server exited early: $(cat "$serverlog")" >&2
+        exit 1
+    }
+    sleep 0.1
+done
+test -n "$port" || {
+    echo "could not discover ftp server port: $(cat "$serverlog")" >&2
+    exit 1
+}
+host="127.0.0.1_${port}"
+
+urls=()
+for name in $names; do
+    urls+=("ftp://127.0.0.1:${port}/${name}.bin")
+done
+
+# -c8, never -c1: a slot is only swapped out while other transfers keep the
+# parser from picking it up. -Z because the swap only logs at debug level, and
+# the run below proves nothing unless it happened. Bounded like every crawl
+# pass: a wedge must fail the test, not hang the job until CI discards the log.
+run_with_timeout 300 httrack "${urls[@]}" -O "$out" --quiet -Z -c8 \
+    --disable-security-limits --robots=0 --timeout=20 --max-time=120 --retries=1 \
+    >"${tmpdir}/log" 2>&1
+
+swapped=$(grep -ac 'slots ready moved to background' "${out}/hts-log.txt" || true)
+test "${swapped:-0}" -gt 0 ||
+    fail "no ready slot was swapped to disk; this run never reached the bug"
+ok "the crawl swapped ready slots to the on-disk table ${swapped} times"
+
+for name in $names; do
+    test -f "${out}/${host}/${name}.bin" || fail "${name}.bin was not mirrored"
+    cmp -s "${out}/${host}/${name}.bin" "${root}/${name}.bin" ||
+        fail "${name}.bin has $(size_of "${out}/${host}/${name}.bin") of the" \
+            "$(size_of "${root}/${name}.bin") bytes served"
+done
+ok "every FTP transfer landed on disk intact"
+
+errors=$(grep -a 'Error:' "${out}/hts-log.txt" || true)
+test -z "$errors" || fail "the crawl reported errors: ${errors}"
+ok "no transfer was reported failed"

tests/111_local-ftp-update-rest.test

@@ -0,0 +1,125 @@
+#!/bin/bash
+#
+# FTP resumed with REST whenever the mirrored file merely existed, so an
+# --update over a complete copy spliced the old body into the new one and the
+# result matched the remote length (#798). Pass 1 is cut short to leave a real
+# partial, pass 2 must still resume it, pass 3 must not.
+
+set -euo pipefail
+
+: "${top_srcdir:=..}"
+testdir=$(cd "$(dirname "$0")" && pwd)
+# shellcheck source=tests/testlib.sh
+. "${testdir}/testlib.sh"
+
+python=$(find_python) || ! echo "python3 not found; skipping" >&2 || exit 77
+command -v httrack >/dev/null || {
+    echo "could not find httrack" >&2
+    exit 1
+}
+
+server=$(nativepath "${testdir}/ftp-server.py")
+tmpdir=$(mktemp -d "${TMPDIR:-/tmp}/httrack_ftp.XXXXXX")
+serverpid=
+cleanup() {
+    stop_server "$serverpid"
+    rm -rf "$tmpdir"
+}
+trap 'set +e; cleanup' EXIT
+trap cleanup HUP INT QUIT PIPE TERM
+
+root="${tmpdir}/root"
+out="${tmpdir}/crawl"
+mode="${tmpdir}/mode"
+cmds="${tmpdir}/cmds"
+mkdir -p "$root" "$out"
+
+fail() {
+    echo "FAIL: $*" >&2
+    exit 1
+}
+ok() { echo "OK: $*"; }
+size_of() { wc -c <"$1" | tr -d '[:space:]'; }
+# hts-log.txt is rewritten per pass, so this only ever sees the pass just run.
+no_errors() {
+    local errors
+    errors=$(grep -a 'Error:' "${out}/hts-log.txt" || true)
+    test -z "$errors" || fail "$1 reported errors: ${errors}"
+}
+# Commands the server saw since the last pass; each pass starts by emptying it.
+sent() { cat "$cmds"; }
+
+# The two generations differ in length and in their first bytes, so a splice
+# shows up whichever end of the file it lands in.
+write_body() {
+    "$python" -c 'import sys; sys.stdout.buffer.write(
+        ("%s-BODY " % sys.argv[1]).encode() + sys.argv[1][:1].encode() * int(sys.argv[2]))' \
+        "$1" "$2" >"${root}/a.bin"
+}
+write_body OLD 8000
+echo '/a.bin truncate' >"$mode"
+
+serverlog="${tmpdir}/server.out"
+"$python" "$server" --root "$(nativepath "$root")" \
+    --mode-file "$(nativepath "$mode")" --log "$(nativepath "$cmds")" \
+    >"$serverlog" 2>&1 &
+serverpid=$!
+port=
+for _ in $(seq 1 300); do
+    line=$(grep -m1 '^PORT ' "$serverlog" 2>/dev/null) && port="${line#PORT }" && break
+    kill -0 "$serverpid" 2>/dev/null || {
+        echo "ftp server exited early: $(cat "$serverlog")" >&2
+        exit 1
+    }
+    sleep 0.1
+done
+test -n "$port" || {
+    echo "could not discover ftp server port: $(cat "$serverlog")" >&2
+    exit 1
+}
+host="127.0.0.1_${port}"
+url="ftp://127.0.0.1:${port}/a.bin"
+mirror="${out}/${host}/a.bin"
+# Bounded like every crawl pass: a wedge must fail the test, not hang the job.
+crawl() { run_with_timeout 300 httrack "$url" -O "$out" --quiet \
+    --disable-security-limits --robots=0 --timeout=20 --max-time=120 --retries=1 \
+    -c1 "$@"; }
+
+# --- pass 1: the transfer dies mid-body and leaves a partial -----------------
+crawl >"${tmpdir}/log1" 2>&1 || true
+test -f "$mirror" || fail "pass 1 mirrored nothing to resume"
+partial=$(size_of "$mirror")
+whole=$(size_of "${root}/a.bin")
+if test "$partial" -le 0 || test "$partial" -ge "$whole"; then
+    fail "pass 1 left ${partial} bytes, wanted a partial of ${whole}"
+fi
+ok "pass 1 left a ${partial}-byte partial copy"
+
+# --- pass 2: the partial is resumed ------------------------------------------
+: >"$mode"
+: >"$cmds"
+crawl >"${tmpdir}/log2" 2>&1
+case "$(sent)" in
+*"REST ${partial}"*) ok "pass 2 resumed at the partial's ${partial} bytes" ;;
+*) fail "pass 2 sent no REST ${partial}; commands were: $(sent)" ;;
+esac
+cmp -s "$mirror" "${root}/a.bin" ||
+    fail "the resumed copy is $(size_of "$mirror") bytes, served $(size_of "${root}/a.bin")"
+# A resume used to count only the appended tail against the remote size, so it
+# was reported "FTP file incomplete" even when it produced the whole file.
+no_errors "pass 2"
+ok "the resumed transfer produced the served body and no error"
+
+# --- pass 3: --update over that complete copy --------------------------------
+write_body NEW 12000
+: >"$cmds"
+crawl --update >"${tmpdir}/log3" 2>&1
+case "$(sent)" in
+*REST*) fail "the update resumed a complete mirror: $(sent)" ;;
+*RETR*) ok "the update re-fetched without REST" ;;
+*) fail "pass 3 never reached RETR; commands were: $(sent)" ;;
+esac
+cmp -s "$mirror" "${root}/a.bin" ||
+    fail "the updated copy is $(size_of "$mirror") bytes, served $(size_of "${root}/a.bin")"
+no_errors "pass 3"
+ok "the update replaced the mirror with the new body"

tests/114_local-update-304-leak.test

@@ -0,0 +1,108 @@
+#!/bin/bash
+#
+# Issue #782: a 304 during --update overwrote the whole response struct with the
+# cache entry, dropping the 8 KB header buffer it owned. Only a leak checker
+# sees it and the sanitized CI leg runs with detect_leaks off, so this one turns
+# it back on around a two-pass mini304 crawl; the fresh pass is the control.
+
+set -eu
+
+: "${top_srcdir:=..}"
+testdir=$(cd "$(dirname "$0")" && pwd)
+# shellcheck source=tests/testlib.sh
+. "${testdir}/testlib.sh"
+server=$(nativepath "${testdir}/local-server.py")
+root=$(nativepath "${testdir}/server-root")
+
+python=$(find_python) || ! echo "python3 not found; skipping" >&2 || exit 77
+
+probe=$(ASAN_OPTIONS=help=1 httrack -O /dev/null --version 2>&1 || true)
+case "$probe" in
+*AddressSanitizer*) ;;
+*)
+    echo "not a sanitized build, skipping" >&2
+    exit 77
+    ;;
+esac
+
+tmpdir=$(mktemp -d "${TMPDIR:-/tmp}/httrack_304leak.XXXXXX") || exit 1
+serverpid=
+cleanup() {
+    stop_server "$serverpid"
+    rm -rf "$tmpdir"
+}
+trap 'set +e; cleanup' EXIT
+trap cleanup HUP INT QUIT PIPE TERM
+
+serverlog="${tmpdir}/server.log"
+: >"$serverlog"
+"$python" "$server" --root "$root" >"$serverlog" 2>&1 &
+serverpid=$!
+port=
+for _ in $(seq 1 50); do
+    line=$(head -n1 "$serverlog" 2>/dev/null)
+    if test "${line%% *}" == "PORT"; then
+        port="${line#PORT }"
+        break
+    fi
+    kill -0 "$serverpid" 2>/dev/null || {
+        echo "server exited early: $(cat "$serverlog")"
+        exit 1
+    }
+    sleep 0.1
+done
+test -n "$port" || {
+    echo "could not discover server port"
+    exit 1
+}
+
+out="${tmpdir}/crawl"
+mkdir "$out"
+url="http://127.0.0.1:${port}/mini304/index.html"
+
+# Last value wins in the sanitizer flag parser, so this overrides the job's
+# settings; the report file, not the exit status, is the verdict.
+asan_base="${ASAN_OPTIONS:+$ASAN_OPTIONS:}detect_leaks=1:abort_on_error=0:exitcode=0"
+
+# run_pass <label> <extra httrack args...>
+run_pass() {
+    local label="$1"
+    shift
+    rm -f "${tmpdir}/asan".*
+    printf '[%s] ..\t' "$label"
+    ASAN_OPTIONS="${asan_base}:log_path=${tmpdir}/asan" \
+        httrack -O "$out" --quiet --disable-security-limits --robots=0 \
+        --timeout=30 --retries=1 -c1 "$@" "$url" >"${tmpdir}/log_${label}" 2>&1 || true
+    report=$(cat "${tmpdir}/asan".* 2>/dev/null || true)
+    test -z "$report" || {
+        echo "FAIL: sanitizer report on the ${label} pass"
+        echo "$report"
+        exit 1
+    }
+    echo "OK (clean)"
+}
+
+run_pass fresh
+run_pass update --update
+# only --warc-file stashes the two header blocks, so the archive limb of the fix
+# runs on this pass alone
+run_pass warc --update --warc-file leak
+
+# Teeth: the update passes must have gone through the 304 path, or a run that
+# re-downloaded everything would report clean having tested nothing.
+printf '[update used the cache] ..\t'
+if grep -aqE "no files updated" "${out}/hts-log.txt"; then
+    echo "OK"
+else
+    echo "FAIL: the update pass did not report unchanged files"
+    exit 1
+fi
+
+# ... and the WARC pass must have written an archive, or it stashed nothing.
+printf '[warc pass archived] ..\t'
+if [ -n "$(find "$out" -name 'leak*.warc*' -size +0c 2>/dev/null)" ]; then
+    echo "OK"
+else
+    echo "FAIL: the --warc-file pass produced no archive"
+    exit 1
+fi

tests/120_local-proxytrack-webdav-default.test

@@ -0,0 +1,121 @@
+#!/bin/bash
+#
+# A PROPFIND whose path is an exact cache entry enumerates that entry's default
+# document under an empty name; proxytrack used to index one byte before it and
+# die on the whole listener.
+
+set -euo pipefail
+
+: "${top_srcdir:=..}"
+# shellcheck source=tests/testlib.sh
+. "$top_srcdir/tests/testlib.sh"
+
+python=$(find_python) || {
+    echo "python3 missing, skipping"
+    exit 77
+}
+command -v curl >/dev/null 2>&1 || {
+    echo "curl missing, skipping"
+    exit 77
+}
+# MSYS cannot reap a native listener, and the orphan wedges the suite (#595).
+if is_windows; then
+    echo "windows: cannot reap a backgrounded proxytrack, skipping"
+    exit 77
+fi
+
+dir=$(mktemp -d)
+ptpid=
+cleanup() {
+    stop_server "$ptpid"
+    rm -rf "$dir"
+}
+trap 'set +e; cleanup' EXIT
+trap 'set +e; cleanup; exit 1' INT TERM HUP
+
+printf 'HTTP/1.1 200 OK\r\nContent-Type: text/html\r\nContent-Length: 5\r\n\r\n' >"$dir/hdr"
+printf 'hello' >"$dir/body"
+alen=$(($(wc -c <"$dir/hdr") + $(wc -c <"$dir/body")))
+{
+    printf 'filedesc://t.arc 0.0.0.0 20250101000000 text/plain 200 - - 0 t.arc 9\n'
+    printf '2 0 test\n'
+    printf '\n\n'
+    printf 'http://example.com/page.html 0.0.0.0 20250101000000 text/html 200 - - 0 t.arc %d\n' "$alen"
+    cat "$dir/hdr" "$dir/body"
+} >"$dir/in.arc"
+
+freeport() {
+    "$python" -c 'import socket; s=socket.socket(); s.bind(("127.0.0.1",0)); print(s.getsockname()[1]); s.close()'
+}
+proxyport=$(freeport)
+icpport=$(freeport)
+
+proxytrack "127.0.0.1:$proxyport" "127.0.0.1:$icpport" "$dir/in.arc" >"$dir/pt.log" 2>&1 &
+ptpid=$!
+waited=0
+until grep -qE "HTTP Proxy installed on|Unable to (initialize a temporary server|create the server)" "$dir/pt.log"; do
+    kill -0 "$ptpid" 2>/dev/null || {
+        echo "FAIL: proxytrack exited before listening"
+        cat "$dir/pt.log"
+        exit 1
+    }
+    test "$waited" -lt 50 || {
+        echo "FAIL: proxytrack never announced its listen port"
+        exit 1
+    }
+    sleep 0.1
+    waited=$((waited + 1))
+done
+grep -q "HTTP Proxy installed on" "$dir/pt.log" || {
+    echo "FAIL: proxytrack failed to bind"
+    cat "$dir/pt.log"
+    exit 1
+}
+
+propfind() {
+    curl -s -i --max-time 30 -X PROPFIND -H "Depth: 1" \
+        "http://127.0.0.1:$proxyport/webdav/example.com/$1"
+}
+
+resp=$(propfind page.html) || {
+    echo "FAIL: PROPFIND on an exact cache entry did not answer"
+    cat "$dir/pt.log"
+    exit 1
+}
+grep -q '^HTTP/1\.[01] 207 ' <<<"$resp" || {
+    echo "FAIL: expected 207 Multi-Status"
+    printf '%s\n' "$resp"
+    exit 1
+}
+grep -q '<displayname>Default Document for the Folder</displayname>' <<<"$resp" || {
+    echo "FAIL: the default document of the entry was not listed"
+    printf '%s\n' "$resp"
+    exit 1
+}
+# The name alone would still pass on a truncated or garbage URL, so pin the
+# href: the default document is the collection path plus an empty name.
+grep -q '<href>/webdav/example\.com/page\.html/</href>' <<<"$resp" || {
+    echo "FAIL: the default document was listed under the wrong href"
+    printf '%s\n' "$resp"
+    exit 1
+}
+responses=$(grep -c '<response ' <<<"$resp" || true)
+test "$responses" -eq 2 || {
+    echo "FAIL: expected the root and its default document, got $responses responses"
+    printf '%s\n' "$resp"
+    exit 1
+}
+
+# The crash killed the process, so a second request is the liveness proof.
+resp=$(propfind "") || {
+    echo "FAIL: proxytrack died serving the previous PROPFIND"
+    cat "$dir/pt.log"
+    exit 1
+}
+grep -q '^HTTP/1\.[01] 207 ' <<<"$resp" || {
+    echo "FAIL: expected 207 Multi-Status on the follow-up listing"
+    printf '%s\n' "$resp"
+    exit 1
+}
+
+echo "OK: PROPFIND on an exact cache entry lists its default document and survives"

tests/13_crawl_proxy_https.test

@@ -31,7 +31,7 @@ cleanup() {
     done
     rm -rf "$tmpdir"
 }
-trap cleanup EXIT
+trap 'set +e; cleanup' EXIT
 
 # self-signed cert for the local TLS origin (httrack does not verify certs)
 openssl req -x509 -newkey rsa:2048 -keyout "$tmpdir/key.pem" \

tests/19_local-connect-fallback.test

@@ -40,9 +40,8 @@ serverpid=
 cleanup() {
     stop_server "$serverpid"
     rm -rf "$tmpdir"
-    return 0
 }
-trap cleanup EXIT
+trap 'set +e; cleanup' EXIT
 
 # bind the live server to 127.0.0.1 only, so 127.0.0.2 refuses the connect
 "$python" "$server" --root "$root" --bind 127.0.0.1 >"$tmpdir/srv.out" 2>"$tmpdir/srv.err" &

tests/23_local-errpage.test

@@ -13,7 +13,10 @@ bash "$top_srcdir/tests/local-crawl.sh" --errors 1 \
     --not-found 'errpage/missing.html' \
     httrack 'BASEURL/errpage/index.html' '-o0'
 
-# Control -o1 (default): the 404 error page is written.
+# Control -o1 (default): the 404 body is the server's verbatim, no HTTrack marker (#787); good.html proves the marker check can fire.
 bash "$top_srcdir/tests/local-crawl.sh" --errors 1 \
     --found 'errpage/missing.html' \
+    --file-matches 'errpage/missing.html' '404 error body' \
+    --file-not-matches 'errpage/missing.html' 'HTTrack' \
+    --file-matches 'errpage/good.html' 'HTTrack' \
     httrack 'BASEURL/errpage/index.html' '-o1'

tests/24_local-resume-overlap.test

@@ -24,7 +24,8 @@ cleanup() {
     stop_server "$serverpid"
     rm -rf "$tmpdir"
 }
-trap cleanup EXIT HUP INT QUIT PIPE TERM
+trap 'set +e; cleanup' EXIT
+trap cleanup HUP INT QUIT PIPE TERM
 
 # OVERLAP_COUNTER gets a byte per flaky.bin request so pass 1 knows when to interrupt.
 serverlog="${tmpdir}/server.log"

tests/40_local-why.test

@@ -6,7 +6,7 @@ set -euo pipefail
 # --why: report which +/- filter rule decides for a URL, without crawling.
 
 tmpdir="$(mktemp -d)"
-trap 'rm -rf "$tmpdir"' EXIT
+trap 'set +e; rm -rf "$tmpdir"' EXIT
 
 why() {
     local want="$1" out

tests/52_local-socks5.test

@@ -34,7 +34,7 @@ cleanup() {
     done
     rm -rf "$tmpdir"
 }
-trap cleanup EXIT
+trap 'set +e; cleanup' EXIT
 
 openssl req -x509 -newkey rsa:2048 -keyout "$tmpdir/key.pem" \
     -out "$tmpdir/cert.pem" -days 2 -nodes -subj "/CN=127.0.0.1" \

tests/53_local-proxytrack-arc-reason.test

@@ -5,7 +5,7 @@
 set -euo pipefail
 
 dir=$(mktemp -d)
-trap 'rm -rf "$dir"' EXIT
+trap 'set +e; rm -rf "$dir"' EXIT
 
 printf 'HTTP/1.1 404 Not Found Here At All\r\nContent-Type: text/html\r\nLast-Modified: Wed, 01 Jan 2025 00:00:00 GMT\r\nContent-Length: 5\r\n\r\n' >"$dir/hdr"
 printf 'hello' >"$dir/body"