Merge fix/cache-repair-rename into fix/refetch-backup-name

Carries the here-string reconciliation with #822 and the aside
directory-refusal fix. TESTS tail keeps all four new entries in order.

Signed-off-by: Xavier Roche <roche@httrack.com>

.github/workflows/windows-build.yml

@@ -211,7 +211,8 @@ jobs:
           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 116_engine-rtrim.test; do
+                   60_crawl-log-salvage.test 106_engine-repair-rename.test \
+                   108_engine-refetch-backup.test; do
             elapsed=$((SECONDS - started))
             if [ "$elapsed" -ge "$suite_deadline" ]; then
               echo "::error::suite deadline: ${elapsed}s elapsed, stopping before $t"

AGENTS.md

@@ -30,12 +30,14 @@ the operational checklist: toolchain, invariants, and how to ship a change.
   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 `$?`, so save it first if teardown reads it.
-- Never assert with `cmd | grep -q MARKER && fail`. Under `pipefail` the
-  pipeline is non-zero both when `cmd` fails and when `grep -q` matches early
-  and SIGPIPEs it, so the `&&` never fires and a probe that proved nothing reads
-  as "marker absent". Capture the reply, assert the status line it must carry
-  (an empty, truncated or redirected one is marker-free too), then match with a
-  here-string.
+- Never pipe into `grep -q`: it exits on the first match, so whatever the
+  producer had left to write takes SIGPIPE, and under `pipefail` that becomes
+  the pipeline's status. `cmd | grep -q M && fail` then never fires and a probe
+  that proved nothing reads as "marker absent"; `cmd | grep -q M || fail` fails
+  a test whose marker was present. bash issues one `write()` per line, so any
+  match that is not on the last line is exposed. Capture the reply, assert the
+  status line it must carry (an empty, truncated or redirected one is
+  marker-free too), then match with a here-string: `grep -q M <<<"$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/htsalias.c

@@ -501,11 +501,13 @@ int optinclude_file(const char *name, int *argc, char **argv, char *x_argvblk,
       /* read line */
       linput(fp, line, 250);
       hts_lowcase(line);
-      /* trim first: a blank line is skipped, not parsed as an option */
-      hts_rtrim(line, HTS_REALSPACES);
       if (strnotempty(line)) {
         /* no comment line: # // ; */
         if (strchr("#/;", line[0]) == NULL) {
+          /* right trim */
+          a = line + strlen(line) - 1;
+          while(is_realspace(*a))
+            *(a--) = '\0';
           /* jump "set " and spaces */
           a = line;
           while(is_realspace(*a))
@@ -575,6 +577,7 @@ int optinclude_file(const char *name, int *argc, char **argv, char *x_argvblk,
             }
           }
         }
+
       }
     }
     fclose(fp);

src/htsback.c

@@ -596,6 +596,41 @@ int back_nsoc_overall(const struct_back * sback) {
   return n;
 }
 
+/* Reserved subdirectory holding a mirrored file's temporaries, beside it. */
+#define HTS_TMPDIR "hts-tmp"
+
+/* Build save's temporary as <dir>/hts-tmp/<name>.<ext>. Appending the extension
+   to save instead put it in the mirror namespace, so a site serving <path>.bak
+   had its copy taken as the backup and then unlinked (#774). HTS_FALSE (dest
+   emptied) if it would not fit. Note: utf-8. */
+static hts_boolean back_tmpname(char *dest, size_t size, const char *save,
+                                const char *ext) {
+  const char *const slash = strrchr(save, '/');
+  const int dirlen = slash != NULL ? (int) (slash - save) + 1 : 0;
+
+  if (!slprintfbuff(dest, size, "%.*s" HTS_TMPDIR "/%s.%s", dirlen, save,
+                    slash != NULL ? slash + 1 : save, ext)) {
+    dest[0] = '\0';
+    return HTS_FALSE;
+  }
+  return HTS_TRUE;
+}
+
+/* Note: utf-8 */
+void back_tmpdir_drop(const char *tmp) {
+  char BIGSTK dir[HTS_URLMAXSIZE * 2];
+  const char *slash;
+
+  if (tmp == NULL || (slash = strrchr(tmp, '/')) == NULL)
+    return;
+  if (!strclipbuff(dir, sizeof(dir), tmp))
+    return;
+  dir[slash - tmp] = '\0';
+  slash = strrchr(dir, '/');
+  if (strcmp(slash != NULL ? slash + 1 : dir, HTS_TMPDIR) == 0)
+    (void) RMDIR(dir);
+}
+
 /* generate temporary file on lien_back */
 /* Note: utf-8 */
 static int create_back_tmpfile(httrackp *opt, lien_back *const back,
@@ -603,12 +638,10 @@ static int create_back_tmpfile(httrackp *opt, lien_back *const back,
   // do not use tempnam() but a regular filename
   back->tmpfile_buffer[0] = '\0';
   if (back->url_sav[0] != '\0') {
-    /* same capacity as url_sav, so truncation drops the extension and aliases
-       the temp name onto the live file that back_finalize_backup() UNLINKs */
-    if (!sprintfbuff(back->tmpfile_buffer, "%s.%s", back->url_sav, ext)) {
+    if (!back_tmpname(back->tmpfile_buffer, sizeof(back->tmpfile_buffer),
+                      back->url_sav, ext)) {
       hts_log_print(opt, LOG_WARNING, "temporary filename too long for %s",
                     back->url_sav);
-      back->tmpfile_buffer[0] = '\0';
       return -1;
     }
     back->tmpfile = back->tmpfile_buffer;
@@ -646,7 +679,11 @@ void back_refetch_backup(httrackp *opt, lien_back *const back) {
       if (fexist_utf8(back->tmpfile))
         hts_log_print(opt, LOG_WARNING, "replacing leftover backup %s",
                       back->tmpfile);
-      saved = hts_rename_over(back->url_sav, back->tmpfile);
+      saved = hts_rename_over(opt, back->url_sav, back->tmpfile);
+      /* Another slot sharing the directory may have removed it between the
+         structcheck above and the rename: recreate it and try once more. */
+      if (!saved && structcheck(back->tmpfile) == 0)
+        saved = hts_rename_over(opt, back->url_sav, back->tmpfile);
     }
     if (!saved) {
       hts_log_print(opt, LOG_WARNING | LOG_ERRNO,
@@ -670,16 +707,22 @@ static hts_boolean back_transfer_failed(const int statuscode) {
   }
 }
 
-/* Commit or restore a re-fetch backup (#77 follow-up): a re-fetch over an
-   existing file moved the good copy to back->tmpfile before truncating url_sav.
-   commit keeps the new file and drops the backup; else restore it so an aborted
-   transfer leaves the previous copy intact. Skips the zlib .z temp. */
-static void back_finalize_backup(httrackp *opt, lien_back *const back,
-                                 const hts_boolean commit) {
+hts_boolean back_finalize_backup(httrackp *opt, lien_back *const back,
+                                 hts_boolean commit) {
+  const hts_boolean wanted = commit;
+
   if (back->tmpfile == NULL || back->r.compressed)
-    return;
+    return HTS_TRUE;
+  /* Nothing to commit to: filecreate() can fail after the backup was taken,
+     and dropping it then loses both copies (#775). */
+  if (commit && !fexist_utf8(back->url_sav)) {
+    hts_log_print(opt, LOG_WARNING, "%s was never created; restoring %s",
+                  back->url_sav, back->tmpfile);
+    commit = HTS_FALSE;
+  }
   if (commit) {
     (void) UNLINK(back->tmpfile); /* new copy is good; drop the backup */
+    back_tmpdir_drop(back->tmpfile);
   } else {
     if (back->r.out != NULL) {
       fclose(back->r.out);
@@ -687,12 +730,15 @@ 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);
+    else
+      back_tmpdir_drop(back->tmpfile);
   }
   back->tmpfile = NULL;
+  return commit == wanted ? HTS_TRUE : HTS_FALSE;
 }
 
 // objet (lien) téléchargé ou transféré depuis le cache
@@ -794,12 +840,21 @@ int back_finalize(httrackp * opt, cache_back * cache, struct_back * sback,
                     hts_codec_parse(back[p].r.contentencoding);
                 /* Never decode over url_sav: a failed decode would destroy the
                    copy an --update re-fetch is supposed to refresh (#557). */
-                char BIGSTK unpacked[HTS_URLMAXSIZE * 2 + 4]; // room for ".u"
+                char BIGSTK unpacked[HTS_URLMAXSIZE * 2];
                 LLint size;
 
-                snprintf(unpacked, sizeof(unpacked), "%s.u", back[p].url_sav);
-                if ((size = hts_codec_unpack(codec, back[p].tmpfile,
-                                             unpacked)) >= 0) {
+                /* fits whenever the .z temp it decodes from did */
+                if (!back_tmpname(unpacked, sizeof(unpacked), back[p].url_sav,
+                                  "u")) {
+                  back[p].r.statuscode = STATUSCODE_INVALID;
+                  strcpybuff(back[p].r.msg, "Error when decompressing (the "
+                                            "temporary filename is too long)");
+                  /* as the decode-failure branch below: never let the coded
+                     bytes be committed as the page */
+                  if (!back[p].r.is_write)
+                    deleteaddr(&back[p].r);
+                } else if ((size = hts_codec_unpack(codec, back[p].tmpfile,
+                                                    unpacked)) >= 0) {
                   back[p].r.size = back[p].r.totalsize = size;
                   if (back[p].r.is_write) {
                     /* Sample the previous copy now: the rename below replaces
@@ -818,7 +873,7 @@ 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);
@@ -871,6 +926,7 @@ int back_finalize(httrackp * opt, cache_back * cache, struct_back * sback,
               /* ensure that no remaining temporary file exists */
               if (back[p].tmpfile != NULL) {
                 unlink(back[p].tmpfile);
+                back_tmpdir_drop(back[p].tmpfile); /* the .u went with it */
                 back[p].tmpfile = NULL;
               }
             }
@@ -883,7 +939,14 @@ int back_finalize(httrackp * opt, cache_back * cache, struct_back * sback,
         }
         /* Body fully received: keep the freshly written url_sav, drop the
            backup of the previous copy. */
-        back_finalize_backup(opt, &back[p], HTS_TRUE);
+        if (!back_finalize_backup(opt, &back[p], HTS_TRUE)) {
+          /* The previous copy is back because the new one was never created;
+             caching this response's validators against it would pin the stale
+             body on every later --update. */
+          if (fexist_utf8(back[p].url_sav))
+            filenote(&opt->state.strc, back[p].url_sav, NULL);
+          return -1;
+        }
         /* Write mode to disk */
         if (back[p].r.is_write && back[p].r.adr != NULL) {
           freet(back[p].r.adr);
@@ -1719,6 +1782,7 @@ int back_clear_entry(lien_back * back) {
     // only for security
     if (back->tmpfile && back->tmpfile[0] != '\0') {
       (void) unlink(back->tmpfile);
+      back_tmpdir_drop(back->tmpfile);
       back->tmpfile = NULL;
     }
     // headers

src/htsback.h

@@ -143,6 +143,18 @@ int back_finalize(httrackp * opt, cache_back * cache, struct_back * sback,
    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);
+/* Commit or restore a re-fetch backup (#77 follow-up): a re-fetch over an
+   existing file moved the good copy to back->tmpfile before truncating url_sav.
+   commit keeps the new file and drops the backup, unless url_sav was never
+   created; else restore it so an aborted transfer leaves the previous copy
+   intact. Skips the zlib .z temp. HTS_FALSE when a requested commit had to
+   restore instead: the caller then holds the OLD body and must not cache this
+   response's validators against it. */
+hts_boolean back_finalize_backup(httrackp *opt, lien_back *const back,
+                                 hts_boolean commit);
+/* Remove the reserved directory a temporary sat in, once the last slot sharing
+   it is done; a non-empty one just refuses. No-op outside that directory. */
+void back_tmpdir_drop(const char *tmp);
 /* -#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);

src/htsbauth.c

@@ -491,7 +491,7 @@ char *bauth_prefix(char *prefix, const char *adr, const char *fil) {
   if (a)
     *a = '\0';
   if (strchr(prefix, '/')) {
-    a = hts_lastcharptr(prefix);
+    a = prefix + strlen(prefix) - 1;
     while(*a != '/')
       a--;
     *(a + 1) = '\0';

src/htscache.c

@@ -957,6 +957,35 @@ htsblk *cache_header(httrackp * opt, cache_back * cache, const char *adr,
     return NULL;
 }
 
+const char *cache_repair(httrackp *opt, const char *name,
+                         unsigned long *entries, unsigned long *bytes) {
+  char BIGSTK repairname[HTS_URLMAXSIZE * 2];
+  unzFile zip;
+
+  *entries = 0;
+  *bytes = 0;
+  if (!slprintfbuff(repairname, sizeof(repairname), "%s%s",
+                    StringBuff(opt->path_log), "hts-cache/repair.zip"))
+    return "the repair path is too long";
+  if (unzRepair(name, repairname,
+                fconcat(OPT_GET_BUFF(opt), OPT_GET_BUFF_SIZE(opt),
+                        StringBuff(opt->path_log), "hts-cache/repair.tmp"),
+                entries, bytes) != Z_OK)
+    return "could not repair the cache";
+  /* unzRepair writes an end-of-central-directory record whatever it found, so
+     an input holding no local file header at all yields a valid empty archive
+     and a short write yields a truncated one. Only an archive that holds
+     something and opens may replace the cache (#824). */
+  if (*entries == 0)
+    return "the repaired cache holds no entry, keeping the damaged one";
+  if ((zip = hts_unzOpen_utf8(repairname)) == NULL)
+    return "the repaired cache does not open, keeping the damaged one";
+  unzClose(zip);
+  if (!hts_rename_over(opt, repairname, name))
+    return "could not put the repaired cache in place";
+  return NULL;
+}
+
 // Initialisation du cache: créer nouveau, renomer ancien, charger..
 void cache_init(cache_back * cache, httrackp * opt) {
   // ---
@@ -985,6 +1014,7 @@ 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),
@@ -1025,8 +1055,9 @@ void cache_init(cache_back * cache, httrackp * opt) {
       // Corrupted ZIP file ? Try to repair!
       if (cache->zipInput == NULL && !cache->ro) {
         char *name;
-        uLong repaired = 0;
-        uLong repairedBytes = 0;
+        const char *why;
+        unsigned long repaired = 0;
+        unsigned long repairedBytes = 0;
 
         if (!cache->ro) {
           name =
@@ -1039,25 +1070,16 @@ void cache_init(cache_back * cache, httrackp * opt) {
         }
         hts_log_print(opt, LOG_WARNING,
                       "Cache: damaged cache, trying to repair");
-        /* mztools has no UTF-8 hook, so repairing a corrupt cache under a
-           non-ASCII path_log fails cleanly (re-crawl), never forks a twin. */
-        if (unzRepair
-            (name,
-             fconcat(OPT_GET_BUFF(opt), OPT_GET_BUFF_SIZE(opt), StringBuff(opt->path_log),
-                     "hts-cache/repair.zip"), fconcat(OPT_GET_BUFF(opt), OPT_GET_BUFF_SIZE(opt),
-                                                      StringBuff(opt->path_log),
-                                                      "hts-cache/repair.tmp"),
-             &repaired, &repairedBytes) == Z_OK) {
-          UNLINK(name);
-          RENAME(fconcat(OPT_GET_BUFF(opt), OPT_GET_BUFF_SIZE(opt),
-                         StringBuff(opt->path_log), "hts-cache/repair.zip"),
-                 name);
-          cache->zipInput = hts_unzOpen_utf8(name);
+        why = cache_repair(opt, name, &repaired, &repairedBytes);
+        if (why != NULL) {
+          hts_log_print(opt, LOG_WARNING | LOG_ERRNO, "Cache: %s", why);
+        } else if ((cache->zipInput = hts_unzOpen_utf8(name)) != NULL) {
           hts_log_print(opt, LOG_WARNING,
                         "Cache: %d bytes successfully recovered in %d entries",
                         (int) repairedBytes, (int) repaired);
         } else {
-          hts_log_print(opt, LOG_WARNING, "Cache: could not repair the cache");
+          hts_log_print(opt, LOG_WARNING,
+                        "Cache: the repaired cache could not be reopened");
         }
       }
       // Opened ?

src/htscache.h

@@ -78,6 +78,14 @@ htsblk *cache_header(httrackp * opt, cache_back * cache, const char *adr,
                      const char *fil, htsblk * r);
 void cache_init(cache_back * cache, httrackp * opt);
 
+/* Recover the damaged cache at name into hts-cache/repair.zip and move it over
+   name, storing what was recovered in *entries and *bytes. Returns NULL on
+   success, else a reason the caller reports: a recovery that is empty or does
+   not open never replaces the cache, and neither does one that cannot be moved
+   into place (#786, #824). Note: utf-8. */
+const char *cache_repair(httrackp *opt, const char *name,
+                         unsigned long *entries, unsigned long *bytes);
+
 /* Which hts-cache/ generation (new.* vs old.*) is authoritative. */
 typedef enum {
   CACHE_RECONCILE_PROMOTE,     /* no new cache: promote the old generation */

src/htscore.c

@@ -3774,7 +3774,8 @@ int htsAddLink(htsmoduleStruct * str, char *link) {
         strcpybuff(codebase, heap(ptr)->fil);
       else
         strcpybuff(codebase, heap(heap(ptr)->precedent)->fil);
-      a = hts_lastcharptr(codebase);
+      // empty codebase has no last char; codebase-1 would underflow
+      a = codebase[0] != '\0' ? codebase + strlen(codebase) - 1 : codebase;
       while((*a) && (*a != '/') && (a > codebase))
         a--;
       if (*a == '/')

src/htscoremain.c

@@ -2160,8 +2160,9 @@ static int hts_main_internal(int argc, char **argv, httrackp * opt) {
               case 'R':
                 {
                   char *name;
-                  uLong repaired = 0;
-                  uLong repairedBytes = 0;
+                  const char *why;
+                  unsigned long repaired = 0;
+                  unsigned long repairedBytes = 0;
 
                   if (fexist_utf8(fconcat(
                           OPT_GET_BUFF(opt), OPT_GET_BUFF_SIZE(opt),
@@ -2184,24 +2185,15 @@ static int hts_main_internal(int argc, char **argv, httrackp * opt) {
                     return 1;
                   }
                   fprintf(stderr, "Cache: trying to repair %s\n", name);
-                  if (unzRepair
-                      (name,
-                       fconcat(OPT_GET_BUFF(opt), OPT_GET_BUFF_SIZE(opt), StringBuff(opt->path_log),
-                               "hts-cache/repair.zip"),
-                       fconcat(OPT_GET_BUFF(opt), OPT_GET_BUFF_SIZE(opt), StringBuff(opt->path_log),
-                               "hts-cache/repair.tmp"), &repaired,
-                       &repairedBytes) == Z_OK) {
-                    UNLINK(name);
-                    RENAME(fconcat(OPT_GET_BUFF(opt), OPT_GET_BUFF_SIZE(opt),
-                                   StringBuff(opt->path_log),
-                                   "hts-cache/repair.zip"),
-                           name);
-                    fprintf(stderr,
-                            "Cache: %d bytes successfully recovered in %d entries\n",
-                            (int) repairedBytes, (int) repaired);
-                  } else {
-                    fprintf(stderr, "Cache: could not repair the cache\n");
+                  why = cache_repair(opt, name, &repaired, &repairedBytes);
+                  if (why != NULL) {
+                    fprintf(stderr, "Cache: %s\n", why);
+                    return 1;
                   }
+                  fprintf(
+                      stderr,
+                      "Cache: %d bytes successfully recovered in %d entries\n",
+                      (int) repairedBytes, (int) repaired);
                 }
                 return 0;
                 break;

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 
             }
@@ -617,9 +620,12 @@ 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,

src/htshelp.c

@@ -558,8 +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

@@ -1322,7 +1322,7 @@ void treathead(t_cookie * cookie, const char *adr, const char *fil, htsblk * ret
       p++;                      // sauter espaces
     if ((int) strlen(rcvd + p) < 250) { // pas trop long?
       char tmp[256];
-      char *a = NULL;
+      char *a = NULL, *b = NULL;
 
       strcpybuff(tmp, rcvd + p);
       a = strstr(tmp, "filename=");
@@ -1335,9 +1335,15 @@ void treathead(t_cookie * cookie, const char *adr, const char *fil, htsblk * ret
 
           while((c = strchr(a, '/')))   /* skip all / (see RFC2616) */
             a = c + 1;
-          hts_rtrim(a, HTS_SPACES);
-          if ((int) strlen(a) < 200) { // pas trop long?
-            strcpybuff(retour->cdispo, a);
+          b = a + strlen(a) - 1;
+          while(is_space(*b))
+            b--;
+          b++;
+          if (b) {
+            *b = '\0';
+            if ((int) strlen(a) < 200) {        // pas trop long?
+              strcpybuff(retour->cdispo, a);
+            }
           }
         }
       }
@@ -3309,9 +3315,8 @@ int ishtml(httrackp * opt, const char *fil) {
   }
 
   /* Search for known ext */
-  for (a = hts_lastcharptr(fil_noquery);
-       *a != '.' && *a != '/' && a > fil_noquery; a--)
-    ;
+  for(a = fil_noquery + strlen(fil_noquery) - 1;
+      *a != '.' && *a != '/' && a > fil_noquery; a--) ;
   if (*a == '.') {              // a une extension
     char BIGSTK fil_noquery[HTS_URLMAXSIZE * 2];
     char *b;
@@ -4248,8 +4253,9 @@ HTSEXT_API hts_boolean get_httptype_sized(httrackp *opt, char *s, size_t ssize,
     return 1;
   } else {
     /* Check html -> text/html */
-    const char *a = hts_lastcharptr(fil);
+    const char *a = fil + strlen(fil) - 1;
 
+    /* a < fil when fil is empty: bound before dereferencing */
     while ((a > fil) && (*a != '.') && (*a != '/'))
       a--;
     if (a >= fil && *a == '.' && strlen(a) < 32) {

src/htsname.c

@@ -74,6 +74,41 @@ static const char *hts_tbdev[] = {
   ""
 };
 
+/* Directories the engine owns inside the mirror. A URL able to name one lands
+   on the cache or on another slot's temporary and destroys it (#774), so they
+   are escaped like the DOS devices are. */
+static const char *hts_tbreserved[] = {"/hts-cache", "/hts-tmp", ""};
+
+/* Replace /foo/<reserved>/bar by /foo/<reserved>_/bar, matching a whole path
+   component only (case-insensitively: the filesystem may be too). */
+static void escapeReservedNames(char *save, size_t size,
+                                const char *const *names) {
+  int i;
+
+  for (i = 0; names[i][0] != '\0'; i++) {
+    const char *a = save;
+    const size_t len = strlen(names[i]);
+
+    while ((a = strstrcase(a, names[i]))) {
+      switch ((int) a[len]) {
+      case '\0':
+      case '/':
+      case '.': {
+        char BIGSTK tempo[HTS_URLMAXSIZE * 2];
+
+        tempo[0] = '\0';
+        strncatbuff(tempo, save, (int) (a - save) + (int) len);
+        strcatbuff(tempo, "_");
+        strcatbuff(tempo, a + len);
+        /* clip rather than abort: the name comes from the wire */
+        (void) strclipbuff(save, size, tempo);
+      } break;
+      }
+      a += len;
+    }
+  }
+}
+
 /* Strip all // */
 static void cleanDoubleSlash(char *s) {
   int i, j;
@@ -823,7 +858,7 @@ int url_savename(lien_adrfilsave *const afs,
   // Change the extension? e.g. php3 saved as html, cgi as html or gif/xbm
   // depending on the resolved type.
   if (ext_chg && !opt->no_type_change) {
-    char *a = hts_lastcharptr(fil);
+    char *a = fil + strlen(fil) - 1;
 
     if ((opt->debug > 1) && (opt->log != NULL)) {
       if (ext_chg == 1)
@@ -858,7 +893,7 @@ int url_savename(lien_adrfilsave *const afs,
   }
   // Rechercher premier / et dernier .
   {
-    const char *a = hts_lastcharptr(fil);
+    const char *a = fil + strlen(fil) - 1;
 
     // passer structures
     start_pos = fil;
@@ -1203,29 +1238,29 @@ int url_savename(lien_adrfilsave *const afs,
     switch (opt->savename_type % 100) {
     case 4:
     case 5:{                   // séparer par types
-      const char *a = hts_lastcharptr(fil);
+        const char *a = fil + strlen(fil) - 1;
 
-      // passer structures
-      while ((a > fil) && (*a != '/') && (*a != '\\'))
-        a--;
-      if ((*a == '/') || (*a == '\\'))
-        a++;
-
-      // html?
-      if ((ext_chg != 0) ? (ishtml_ext(ext) == 1) : (ishtml(opt, fil) == 1)) {
-        if (opt->savename_type % 100 == 5)
-          strcatbuff(afs->save, "html/");
-      } else {
-        const char *a = hts_lastcharptr(fil);
-
-        while ((a > fil) && (*a != '/') && (*a != '.'))
+        // passer structures
+        while((a > fil) && (*a != '/') && (*a != '\\'))
           a--;
-        if (*a != '.')
-          strcatbuff(afs->save, "other");
-        else
-          strcatbuff(afs->save, a + 1);
-        strcatbuff(afs->save, "/");
-      }
+        if ((*a == '/') || (*a == '\\'))
+          a++;
+
+        // html?
+        if ((ext_chg != 0) ? (ishtml_ext(ext) == 1) : (ishtml(opt, fil) == 1)) {
+          if (opt->savename_type % 100 == 5)
+            strcatbuff(afs->save, "html/");
+        } else {
+          const char *a = fil + strlen(fil) - 1;
+
+          while((a > fil) && (*a != '/') && (*a != '.'))
+            a--;
+          if (*a != '.')
+            strcatbuff(afs->save, "other");
+          else
+            strcatbuff(afs->save, a + 1);
+          strcatbuff(afs->save, "/");
+        }
         /*strcatbuff(save,a); */
         /* add name */
         ADD_STANDARD_NAME(0);
@@ -1258,7 +1293,7 @@ int url_savename(lien_adrfilsave *const afs,
         }
         afs->save[i + j] = '\0';
         // ajouter extension
-        a = hts_lastcharptr(fil);
+        a = fil + strlen(fil) - 1;
         while((a > fil) && (*a != '/') && (*a != '.'))
           a--;
         if (*a == '.') {
@@ -1303,7 +1338,7 @@ int url_savename(lien_adrfilsave *const afs,
   // cela évite les /chez/toto et les /chez/toto/index.html incompatibles
   if (opt->savename_type != -1 &&
       opt->savename_delayed != HTS_SAVENAME_DELAYED_HARD) {
-    char *a = hts_lastcharptr(afs->save);
+    char *a = afs->save + strlen(afs->save) - 1;
 
     while((a > afs->save) && (*a != '.') && (*a != '/'))
       a--;
@@ -1369,35 +1404,12 @@ int url_savename(lien_adrfilsave *const afs,
   // éliminer les // (comme ftp://)
   cleanDoubleSlash(afs->save);
 
+  /* Runs on every platform, and before path_html is prepended below, so the
+     user's own output directory is never renamed. */
+  escapeReservedNames(afs->save, sizeof(afs->save), hts_tbreserved);
+
 #if HTS_OVERRIDE_DOS_FOLDERS
-  /* Replace /foo/nul/bar by /foo/nul_/bar */
-  {
-    int i = 0;
-
-    while(hts_tbdev[i][0]) {
-      const char *a = afs->save;
-
-      while((a = strstrcase(a, hts_tbdev[i]))) {
-        switch ((int) a[strlen(hts_tbdev[i])]) {
-        case '\0':
-        case '/':
-        case '.':
-          {
-            char BIGSTK tempo[HTS_URLMAXSIZE * 2];
-
-            tempo[0] = '\0';
-            strncatbuff(tempo, afs->save, (int) (a - afs->save) + strlen(hts_tbdev[i]));
-            strcatbuff(tempo, "_");
-            strcatbuff(tempo, a + strlen(hts_tbdev[i]));
-            strcpybuff(afs->save, tempo);
-          }
-          break;
-        }
-        a += strlen(hts_tbdev[i]);
-      }
-      i++;
-    }
-  }
+  escapeReservedNames(afs->save, sizeof(afs->save), hts_tbdev);
 
   /* Strip ending . or ' ' forbidden on windoz */
   cleanEndingSpaceOrDot(afs->save);
@@ -1420,10 +1432,8 @@ int url_savename(lien_adrfilsave *const afs,
   if (opt->savename_83 > 0) {
     char *a, *last;
 
-    for (last = hts_lastcharptr(afs->save);
-         last != afs->save && *last != '/' && *last != '\\' && *last != '.';
-         last--)
-      ;
+    for(last = afs->save + strlen(afs->save) - 1;
+        last != afs->save && *last != '/' && *last != '\\' && *last != '.'; last--) ;
     if (*last != '.') {
       last = NULL;
     }
@@ -1678,8 +1688,8 @@ int url_savename(lien_adrfilsave *const afs,
 #endif
         } else {                // utilisé par un AUTRE, changer de nom
           char BIGSTK tempo[HTS_URLMAXSIZE * 2];
-          char *a = hts_lastcharptr(afs->save);
-          size_t stem;
+          char *a = afs->save + strlen(afs->save) - 1;
+          char *b;
           int n = 2;
           char collisionSeparator =
               ((opt->savename_83 != HTS_SAVENAME_83_ISO9660) ? '-' : '_');
@@ -1701,16 +1711,18 @@ int url_savename(lien_adrfilsave *const afs,
             strcatbuff(tempo, afs->save);
 
           // tester la présence d'un -xx (ex: index-2.html -> index-3.html)
-          stem = hts_rtrimlen(tempo, "0123456789");
-          if (stem != 0 && tempo[stem - 1] == collisionSeparator) {
-            sscanf(tempo + stem, "%d", &n);
-            tempo[stem - 1] = '\0'; // couper
+          b = tempo + strlen(tempo) - 1;
+          while(isdigit((unsigned char) *b))
+            b--;
+          if (*b == collisionSeparator) {
+            sscanf(b + 1, "%d", &n);
+            *b = '\0';          // couper
             n++;                // plus un
           }
           // en plus il faut gérer le 8-3 .. pas facile le client
           if (opt->savename_83) {
             int max;
-            char *a = hts_lastcharptr(tempo);
+            char *a = tempo + strlen(tempo) - 1;
 
             while((a > tempo) && (*a != '/'))
               a--;

src/htsparse.c

@@ -2057,7 +2057,7 @@ int htsparse(htsmoduleStruct * str, htsmoduleStructExtended * stre) {
                   }
                   q = strchr(a, '?');   // ne pas traiter après '?'
                   if (!q)
-                    q = hts_lastcharptr(a);
+                    q = a + strlen(a) - 1;
                   while((p = strstr(a, "//")) && (!done)) {     // remplacer // par /
                     if (p > q) {    // après le ? (toto.cgi?param=1//2.3)
                       done = 1; // stopper
@@ -2208,7 +2208,7 @@ int htsparse(htsmoduleStruct * str, htsmoduleStructExtended * stre) {
                 // OUI!!
 #if HTS_TILDE_SLASH
                 if (hts_lastchar(lien) != '/') {
-                  char *a = hts_lastcharptr(lien);
+                  char *a = lien + strlen(lien) - 1;
 
                   // éviter aussi index~1.html
                   while(a > lien && (*a != '~') && (*a != '/')
@@ -2254,7 +2254,7 @@ int htsparse(htsmoduleStruct * str, htsmoduleStructExtended * stre) {
                 // vérifier que l'on ne doit pas ajouter de .class
                 if (!error) {
                   if (add_class) {
-                    char *a = hts_lastcharptr(lien);
+                    char *a = lien + strlen(lien) - 1;
 
                     while((a > lien) && (*a != '/') && (*a != '.'))
                       a--;
@@ -2309,7 +2309,7 @@ int htsparse(htsmoduleStruct * str, htsmoduleStructExtended * stre) {
                         {
                           char *a;
 
-                          a = hts_lastcharptr(lien);
+                          a = lien + strlen(lien) - 1;
                           while((*a) && (*a != '/') && (a > lien))
                             a--;
                           if (*a == '/') {
@@ -2320,8 +2320,8 @@ int htsparse(htsmoduleStruct * str, htsmoduleStructExtended * stre) {
                     }
 
                     if (!error) {       // pas d'erreur?
-                      if (p_type == 2) { // code ET PAS codebase
-                        char *a = hts_lastcharptr(lien);
+                      if (p_type == 2) {        // code ET PAS codebase      
+                        char *a = lien + strlen(lien) - 1;
                         char *start_of_filename = jump_identification(lien);
 
                         if (start_of_filename != NULL

src/htssafe.h

@@ -569,38 +569,6 @@ static HTS_INLINE HTS_UNUSED hts_boolean hts_choplastchar(char *s) {
   return HTS_FALSE;
 }
 
-/* htslib.h's is_space() and is_realspace() as hts_rtrim() sets; -#test=rtrim
-   keeps them in sync. */
-#define HTS_SPACES " \"\n\r\t\f\v'"
-#define HTS_REALSPACES " \n\r\t\f\v"
-
-/* Length of s once its trailing bytes from set are dropped; 0 if they all are.
-   Counts down from the end, so it stops at s rather than below the buffer. */
-static HTS_INLINE HTS_UNUSED size_t hts_rtrimlen(const char *s,
-                                                 const char *set) {
-  size_t len = strlen(s);
-
-  while (len != 0 && strchr(set, s[len - 1]) != NULL)
-    len--;
-  return len;
-}
-
-/* Drop the trailing bytes of s that occur in set. */
-static HTS_INLINE HTS_UNUSED void hts_rtrim(char *s, const char *set) {
-  s[hts_rtrimlen(s, set)] = '\0';
-}
-
-/* Offset of the last character of s, or 0 when s is empty. */
-static HTS_INLINE HTS_UNUSED size_t hts_lastcharoffset(const char *s) {
-  const size_t len = strlen(s);
-
-  return len != 0 ? len - 1 : 0;
-}
-
-/* Address of the last character of S, or of its terminating NUL when S is
-   empty. S is evaluated twice, so pass an lvalue. */
-#define hts_lastcharptr(S) ((S) + hts_lastcharoffset(S))
-
 /* 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

@@ -6137,10 +6137,9 @@ static hts_boolean ro_is(const char *path, const char *data) {
 }
 
 // -#test=renameover <dir>: hts_rename_over() must replace an existing dst and
-// never delete one it did not replace (#779). Which half is live depends on
+// 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) {
-  (void) opt;
   if (argc < 1) {
     fprintf(stderr, "renameover: needs a writable base dir\n");
     return 1;
@@ -6169,7 +6168,7 @@ static int st_renameover(httrackp *opt, int argc, char **argv) {
   ro_put(dst, "old");
   if (replaceable) {
     /* An existing dst must still be replaced: the unlink is for this. */
-    if (!hts_rename_over(src, dst)) {
+    if (!hts_rename_over(opt, src, dst)) {
       fprintf(stderr, "renameover: replacing an existing dst failed: %s\n",
               strerror(errno));
       err++;
@@ -6179,7 +6178,7 @@ static int st_renameover(httrackp *opt, int argc, char **argv) {
     }
   } else {
     /* A failure the unlink cannot fix must leave dst as it was. */
-    if (hts_rename_over(src, dst)) {
+    if (hts_rename_over(opt, src, dst)) {
       fprintf(stderr, "renameover: an unfixable failure reported success\n");
       err++;
     }
@@ -6189,10 +6188,36 @@ static int st_renameover(httrackp *opt, int argc, char **argv) {
     }
   }
 
+  /* 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(src, dst)) {
+  if (hts_rename_over(opt, src, dst)) {
     fprintf(stderr, "renameover: a missing src reported success\n");
     err++;
   }
@@ -6203,16 +6228,177 @@ static int st_renameover(httrackp *opt, int argc, char **argv) {
 
   /* Same, with dst absent too: nothing to lose, still a failure. */
   (void) UNLINK(dst);
-  if (hts_rename_over(src, 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=refetchbackup <dir>: the #77 re-fetch backup must build its temporary
+// inside the reserved hts-tmp directory, whose segment url_savename escapes so
+// no mirrored file can ever sit there (#774), and must never leave the resource
+// without a copy (#775).
+static int st_refetchbackup(httrackp *opt, int argc, char **argv) {
+  lien_back *back;
+  char want[HTS_URLMAXSIZE * 2 + 32];
+  int err = 0;
+
+  if (argc < 1) {
+    fprintf(stderr, "refetchbackup: needs a writable base dir\n");
+    return 1;
+  }
+  back = calloct(1, sizeof(lien_back));
+  if (back == NULL) {
+    fprintf(stderr, "refetchbackup: out of memory\n");
+    return 1;
+  }
+  /* explicit separator: fconcat() joins without one, which would put the
+     temporary in the parent of the directory under test */
+  snprintf(back->url_sav, sizeof(back->url_sav), "%s/refetch.bin", argv[0]);
+  snprintf(want, sizeof(want), "%s/hts-tmp/refetch.bin.bak", argv[0]);
+
+  /* #774: pin the name, so moving the temporary out of the reserved directory
+     cannot pass without url_savename reserving wherever it went instead. */
+  ro_put(back->url_sav, "old");
+  back_refetch_backup(opt, back);
+  if (back->tmpfile == NULL || fexist_utf8(back->url_sav)) {
+    fprintf(stderr, "refetchbackup: the previous copy was not moved aside\n");
+    err++;
+  } else if (strcmp(back->tmpfile, want) != 0) {
+    fprintf(stderr, "refetchbackup: temporary is %s, want %s\n", back->tmpfile,
+            want);
+    err++;
+  }
+  ro_put(back->url_sav, "new"); /* what filecreate() + the transfer produce */
+  back_finalize_backup(opt, back, HTS_TRUE);
+  if (!ro_is(back->url_sav, "new")) {
+    fprintf(stderr, "refetchbackup: the committed copy is not the new one\n");
+    err++;
+  }
+
+  /* #758: only a killed run can leave something there, and it must be replaced
+     rather than disable the backup for good. */
+  if (structcheck(want) != 0) {
+    fprintf(stderr, "refetchbackup: cannot create %s\n", want);
+    freet(back);
+    return 1;
+  }
+  ro_put(want, "leftover");
+  back_refetch_backup(opt, back);
+  if (back->tmpfile == NULL || !ro_is(want, "new")) {
+    fprintf(stderr, "refetchbackup: a leftover temporary blocked the backup\n");
+    err++;
+  }
+
+  /* #775: filecreate() failed, so there is nothing to commit to. Saying so is
+     load-bearing: the caller must not cache this response against the old
+     body, or the next --update gets a 304 pinning it. */
+  (void) UNLINK(back->url_sav);
+  if (back_finalize_backup(opt, back, HTS_TRUE)) {
+    fprintf(stderr, "refetchbackup: a commit that restored reported success\n");
+    err++;
+  }
+  if (!ro_is(back->url_sav, "new")) {
+    fprintf(stderr, "refetchbackup: a commit with no new copy lost both\n");
+    err++;
+  }
+
+  /* An aborted transfer restores, as before. */
+  back_refetch_backup(opt, back);
+  ro_put(back->url_sav, "partial");
+  back_finalize_backup(opt, back, HTS_FALSE);
+  if (!ro_is(back->url_sav, "new")) {
+    fprintf(stderr, "refetchbackup: an aborted re-fetch kept the partial\n");
+    err++;
+  }
+
+  (void) UNLINK(back->url_sav);
+  freet(back);
+  printf("refetchbackup: %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) {
@@ -6710,10 +6896,9 @@ static int st_changes_race(httrackp *opt, int argc, char **argv) {
   return err;
 }
 
-/* The x[strlen(x) - 1] class (#770) and its pointer spelling x + strlen(x) - 1
-   (#781). 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. */
+/* 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 };
 
@@ -6780,52 +6965,11 @@ static int st_lastchar(httrackp *opt, int argc, char **argv) {
   CHECK(s[0] == '\0');
   CHECK(arena[guard] == '#');
 
-  /* the pointer spelling (#781): on an empty string the address must be the
-     terminating NUL, never the byte before it */
-  REPOISON("");
-  CHECK(hts_lastcharoffset(s) == 0);
-  CHECK(hts_lastcharptr(s) == s);
-  CHECK(*hts_lastcharptr(s) == '\0');
-  *hts_lastcharptr(s) = 'Z'; /* a write through it must stay inside s */
-  CHECK(arena[guard] == '#');
-  CHECK(s[0] == 'Z');
-
-  /* the neighbour must not be mistaken for the string's own last byte */
-  REPOISON("");
-  arena[guard] = '/';
-  CHECK(hts_lastcharptr(s) == s);
-  CHECK(*hts_lastcharptr(s) != '/');
-  CHECK(arena[guard] == '/');
-
-  /* the walk-back loops the sites use must stop at once on an empty string */
-  REPOISON("");
-  {
-    const char *p = hts_lastcharptr(s);
-    int steps = 0;
-
-    while (p > s && *p != '/')
-      p--, steps++;
-    CHECK(steps == 0);
-    CHECK(p == s);
-  }
-
-  REPOISON("ab/");
-  CHECK(hts_lastcharoffset(s) == 2);
-  CHECK(hts_lastcharptr(s) == s + 2);
-  CHECK(*hts_lastcharptr(s) == '/');
-  REPOISON("/");
-  CHECK(hts_lastcharptr(s) == s);
-  CHECK(*hts_lastcharptr(s) == '/');
-  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] != '#');
-  REPOISON("");
-  *(s + strlen(s) - 1) = 'X';
-  CHECK(arena[guard] != '#');
 
 #undef REPOISON
 #undef CHECK
@@ -6834,91 +6978,6 @@ static int st_lastchar(httrackp *opt, int argc, char **argv) {
   return err;
 }
 
-/* hts_rtrim() and the sets it is called with. The string starts mid-arena, and
-   the byte below it is poisoned with '#' rather than 0, or the stray NUL the
-   old loop wrote there would read as untouched. */
-static int st_rtrim(httrackp *opt, int argc, char **argv) {
-  enum { off = 8 };
-
-  char arena[24];
-  char *const s = &arena[off];
-  const int guard = off - 1;
-  int err = 0;
-  int c;
-
-  (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)
-
-  /* nothing but spaces: the case that ran the old loop off the front */
-  REPOISON("   ");
-  hts_rtrim(s, HTS_REALSPACES);
-  CHECK(s[0] == '\0');
-  CHECK(arena[guard] == '#');
-
-  /* a space sitting below the string must not be eaten as if it were part of
-     it, which is exactly what the old loop did */
-  REPOISON("   ");
-  arena[guard] = ' ';
-  hts_rtrim(s, HTS_REALSPACES);
-  CHECK(s[0] == '\0');
-  CHECK(arena[guard] == ' ');
-
-  REPOISON("");
-  hts_rtrim(s, HTS_REALSPACES);
-  CHECK(s[0] == '\0');
-  CHECK(arena[guard] == '#');
-
-  REPOISON("a b \t\r\n");
-  hts_rtrim(s, HTS_REALSPACES);
-  CHECK(strcmp(s, "a b") == 0);
-  CHECK(arena[guard] == '#');
-
-  REPOISON("ab");
-  hts_rtrim(s, HTS_REALSPACES);
-  CHECK(strcmp(s, "ab") == 0);
-
-  /* quotes count as space for is_space() but not for is_realspace() */
-  REPOISON("v\" ");
-  hts_rtrim(s, HTS_REALSPACES);
-  CHECK(strcmp(s, "v\"") == 0);
-  REPOISON("v\" ");
-  hts_rtrim(s, HTS_SPACES);
-  CHECK(strcmp(s, "v") == 0);
-
-  /* the sets must stay the macros they stand for */
-  for (c = 1; c < 256; c++) {
-    const char b = (char) c;
-
-    CHECK((strchr(HTS_SPACES, b) != NULL) == (is_space(b) != 0));
-    CHECK((strchr(HTS_REALSPACES, b) != NULL) == (is_realspace(b) != 0));
-  }
-
-  /* control: the canary must be able to fail */
-  REPOISON("   ");
-  s[-1] = '\0';
-  CHECK(arena[guard] != '#');
-
-#undef REPOISON
-#undef CHECK
-
-  printf("rtrim self-test: %s\n", err ? "FAIL" : "OK");
-  return err;
-}
-
 /* ------------------------------------------------------------ */
 /* Registry: name -> handler, with a usage hint and a one-line description. */
 /* ------------------------------------------------------------ */
@@ -6974,10 +7033,8 @@ 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, #781)",
+    {"lastchar", "", "last-char helpers never index before the buffer (#770)",
      st_lastchar},
-    {"rtrim", "", "hts_rtrim never walks below the buffer", st_rtrim},
     {"changes", "", "--changes bucket accounting and JSON escaping (#714)",
      st_changes},
     {"changes-race", "<dir>", "--changes under a late transfer thread (#714)",
@@ -7092,6 +7149,9 @@ static const struct selftest_entry {
      "hts_rename_over(): replace dst, but never delete a dst it did not "
      "replace",
      st_renameover},
+    {"refetchbackup", "<dir>",
+     "the re-fetch backup always leaves a copy, and stays out of the mirror",
+     st_refetchbackup},
     {"direnum", "<dir>",
      "enumerate a long+non-ASCII directory through opendir/readdir",
      st_direnum},

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

@@ -324,7 +324,8 @@ int lienrelatif(char *s, size_t ssize, const char *link, const char *curr_fil) {
   curr = _curr;
   strlcpybuff(curr, curr_fil, sizeof(_curr));
   if ((a = strchr(curr, '?')) == NULL) { // cut at the ? (query parameters)
-    a = hts_lastcharptr(curr);
+    // an empty path has no last character: curr-1 would read before the buffer
+    a = curr[0] != '\0' ? curr + strlen(curr) - 1 : curr;
   }
   while((*a != '/') && (a > curr))
     a--;                        // chercher dernier / du chemin courant
@@ -1437,21 +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;
-  /* Only a dst in the way is something the unlink can clear, and the CRT maps
-     that to EEXIST; it keeps EACCES for a src another process holds, where
-     removing dst would lose a file the retry cannot replace (#790). The src
-     check covers a CRT that reports neither. */
+  /* 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;
-  (void) UNLINK(cdst);
-  return RENAME(csrc, cdst) == 0 ? HTS_TRUE : 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

@@ -137,11 +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. dst is removed only to make room for a src that exists,
-   so a caller whose src was never written keeps its dst; a retry that still
-   fails does not (#790). */
-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

@@ -38,6 +38,7 @@ Please visit our Website: http://www.httrack.com
 
 #include "htscore.h"
 #include "htslib.h"
+#include "htsback.h"
 #include "htstools.h"
 #include "htssafe.h"
 #include "htszlib.h"
@@ -1114,7 +1115,7 @@ 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);
@@ -1354,6 +1355,7 @@ void warc_free_request(htsblk *r) {
     freet(r->warc_resphdr);
     if (r->warc_rawpath != NULL) {
       (void) UNLINK(r->warc_rawpath); /* owns the verbatim spool file */
+      back_tmpdir_drop(r->warc_rawpath);
       freet(r->warc_rawpath);
       r->warc_rawpath = NULL;
     }
@@ -1589,7 +1591,7 @@ 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;

src/proxy/store.c

@@ -903,11 +903,10 @@ int PT_LoadCache__New(PT_Index index_, const char *filename) {
       coucal hashtable = index->hash;
 
       /* Compute base path for this index - the filename MUST be absolute! */
-      for (slashes = 2, abpath = hts_lastcharptr(filename);
-           abpath > filename &&
-           ((*abpath != '/' && *abpath != '\\') || --slashes > 0);
-           abpath--)
-        ;
+      for(slashes = 2, abpath = filename + (int) strlen(filename) - 1;
+          abpath > filename && ((*abpath != '/' && *abpath != '\\')
+                                || --slashes > 0);
+          abpath--) ;
       index->path[0] = '\0';
       if (slashes == 0 && *abpath != 0) {
         int i;
@@ -1500,11 +1499,10 @@ static int PT_LoadCache__Old(PT_Index index_, const char *filename) {
 
       /* -------------------- COPY OF THE __New() CODE -------------------- */
       /* Compute base path for this index - the filename MUST be absolute! */
-      for (slashes = 2, abpath = hts_lastcharptr(filename);
-           abpath > filename &&
-           ((*abpath != '/' && *abpath != '\\') || --slashes > 0);
-           abpath--)
-        ;
+      for(slashes = 2, abpath = filename + (int) strlen(filename) - 1;
+          abpath > filename && ((*abpath != '/' && *abpath != '\\')
+                                || --slashes > 0);
+          abpath--) ;
       index->path[0] = '\0';
       if (slashes == 0 && *abpath != 0) {
         int i;

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

@@ -5,4 +5,5 @@ 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).
-httrack -O /dev/null -#test=backswap | grep -q "backswap self-test: OK"
+out=$(httrack -O /dev/null -#test=backswap)
+grep -q "backswap self-test: OK" <<<"$out"

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-cookieimport.test

@@ -9,4 +9,5 @@ set -euo pipefail
 dir=$(mktemp -d)
 trap 'set +e; rm -rf "$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

@@ -8,4 +8,5 @@ set -euo pipefail
 dir=$(mktemp -d)
 trap 'set +e; rm -rf "$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-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-footer-overflow.test

@@ -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-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-growsize.test

@@ -19,7 +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

@@ -1,8 +1,8 @@
 #!/bin/bash
 #
-# Runs the lastchar self-test (#770, #781), then keeps the idiom it replaced
-# from coming back: x[strlen(x) - 1] and x + strlen(x) - 1 both land one byte
-# before the buffer when x is empty, and the guard is never where they are.
+# 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
 
@@ -33,36 +33,3 @@ test -z "$hits" || {
     echo "$hits" >&2
     exit 1
 }
-
-# Same for the pointer spelling. The three survivors sit in commented-out
-# blocks in htsname.c; the rest are this class being named, plus the self-test's
-# own deliberate underflow.
-hits=$(command grep -rnE '\+ *\(?(int|size_t)?\)? *strlen *\([^)]*\) *- *1' \
-    "$top_srcdir/src" --include='*.c' --include='*.h' --exclude-dir=coucal |
-    grep -v 'htsname\.c:.*char\* a=\(fil+strlen(fil)\|save+strlen(save)\)-1;' |
-    grep -v 'htsselftest\.c:.*pointer spelling x + strlen(x) - 1' |
-    grep -v 'htsselftest\.c:.*\*(s + strlen(s) - 1) =' || true)
-
-test -z "$hits" || {
-    echo "x + strlen(x) - 1 reintroduced; use hts_lastcharptr:" >&2
-    echo "$hits" >&2
-    exit 1
-}
-
-# url_savename() has nine of these sites and reaches all of them with an empty
-# "fil", which "?x=1" produces. Names are asserted loosely, since the point is
-# the run: on unfixed code the sanitized CI leg aborts inside htsname.c.
-for args in "?x=1 text/plain" "?x=1 text/html" "?x=1 text/html type=4"; do
-    # shellcheck disable=SC2086
-    name=$(httrack -#test=savename $args) || {
-        echo "httrack -#test=savename $args exited non-zero: $name" >&2
-        exit 1
-    }
-    case "$name" in
-    "savename: "?*) ;;
-    *)
-        echo "-#test=savename $args produced no name: $name" >&2
-        exit 1
-        ;;
-    esac
-done

tests/01_engine-logcallback.test

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

tests/01_engine-longpath-io.test

@@ -8,4 +8,5 @@ set -euo pipefail
 dir=$(mktemp -d)
 trap 'set +e; rm -rf "$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-mirror-io.test

@@ -9,4 +9,5 @@ set -euo pipefail
 dir=$(mktemp -d)
 trap 'set +e; rm -rf "$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-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

@@ -4,9 +4,9 @@
 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 removing dst cannot
-# fix (#779). The selftest prints the regime it detected; pin it per platform so
-# a leg cannot pass having tested the other half.
+# 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
 
@@ -16,8 +16,9 @@ MINGW* | MSYS_NT*) want=fallback ;; # native rename() refuses an existing target
 esac
 
 out=$(httrack -O /dev/null -#test=renameover "$dir")
-echo "$out" | grep -q "renameover: OK"
-echo "$out" | grep -q "renameover: regime $want"
+grep -q "renameover: OK" <<<"$out"
+grep -q "renameover: regime $want" <<<"$out"
+grep -q "renameover: restore back" <<<"$out"
 
 if [ "$(uname -s)" != "Linux" ]; then
     echo "renameover: LD_PRELOAD interposition is Linux-only here, skipping"
@@ -42,14 +43,29 @@ fi
 # refuses by default. The shim allocates nothing, so the ordering is harmless.
 export ASAN_OPTIONS="${ASAN_OPTIONS:+$ASAN_OPTIONS:}verify_asan_link_order=0"
 
-# The unlink fallback is dead code on POSIX, so borrow Windows' rename().
+# The aside fallback is dead code on POSIX, so borrow Windows' rename().
 out=$(LD_PRELOAD="$RENAMEFAIL_LIB" httrack -O /dev/null \
     -#test=renameover "$dir")
-echo "$out" | grep -q "renameover: OK"
-echo "$out" | grep -q "renameover: regime fallback"
+grep -q "renameover: OK" <<<"$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 "$dir")
-echo "$out" | grep -q "renameover: OK"
-echo "$out" | grep -q "renameover: regime refused"
+grep -q "renameover: OK" <<<"$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

@@ -165,3 +165,20 @@ MINGW* | MSYS* | CYGWIN*)
     name "/$(printf 'a%.0s' {1..300}).php" 'text/html' "$(printf 'a%.0s' {1..300}).html"
     ;;
 esac
+
+# #774: the engine owns hts-cache/ and hts-tmp/ inside the mirror, so a URL must
+# never be able to name one; a site serving them gets the /nul -> nul_ treatment.
+full '/hts-tmp/a.bin' 'application/octet-stream' \
+    '/dev/null/www.example.com/hts-tmp_/a.bin'
+full '/hts-cache/new.zip' 'application/octet-stream' \
+    '/dev/null/www.example.com/hts-cache_/new.zip'
+full '/d/hts-tmp/a.bin.bak' 'application/octet-stream' \
+    '/dev/null/www.example.com/d/hts-tmp_/a.bin.bak'
+# A whole component only, and case-insensitively: the filesystem may be too.
+full '/hts-tmpfoo/a.bin' 'application/octet-stream' \
+    '/dev/null/www.example.com/hts-tmpfoo/a.bin'
+full '/HTS-TMP/a.bin' 'application/octet-stream' \
+    '/dev/null/www.example.com/HTS-TMP_/a.bin'
+# Control: the DOS device names this reuses must still be escaped.
+full '/nul/x.bin' 'application/octet-stream' \
+    '/dev/null/www.example.com/nul_/x.bin'

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-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-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
@@ -17,13 +15,13 @@ 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-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
@@ -15,7 +13,7 @@ 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-warc-wacz.test

@@ -10,7 +10,8 @@ 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

tests/101_local-update-stale-bak.test

@@ -12,8 +12,8 @@ set -euo pipefail
 : "${top_srcdir:=..}"
 
 bash "$top_srcdir/tests/local-crawl.sh" \
-    --plant-file bigtrunc/slow.bin.bak \
-    --plant-dir bigtrunc/fast.bin.bak \
+    --plant-file bigtrunc/hts-tmp/slow.bin.bak \
+    --plant-dir bigtrunc/hts-tmp/fast.bin.bak \
     --rerun-args '--update -M400000' \
     --log-found 'More than 400000 bytes have been transferred.. giving up' \
     --log-found 'replacing leftover backup .*slow\.bin\.bak' \

tests/102_local-ftp-refetch.test

@@ -152,13 +152,15 @@ 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=$(listed changed)
 for name in keep empty; do
-    listed unchanged | grep -qx "${host}/${name}.bin:$(size_of "${tmpdir}/snap/${name}.bin")" ||
+    grep -qx "${host}/${name}.bin:$(size_of "${tmpdir}/snap/${name}.bin")" <<<"$unchanged" ||
         fail "${name}.bin is not reported unchanged at its previous size"
-    if listed changed | grep -q "^${host}/${name}.bin:"; then
+    if grep -q "^${host}/${name}.bin:" <<<"$changed"; then
         fail "${name}.bin is reported changed as well"
     fi
 done
-listed changed | grep -qx "${host}/stay.bin:$(size_of "${out}/${host}/stay.bin")" ||
+grep -qx "${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/106_engine-repair-rename.test

@@ -0,0 +1,173 @@
+#!/bin/bash
+#
+# #786: both cache-repair paths moved the recovered zip onto the cache without
+# checking the move, and announced success either way. #824: they also committed
+# a recovery holding no entry at all. Neither may replace the cache, and both
+# must be reported.
+
+set -euo pipefail
+
+testdir=$(cd "$(dirname "$0")" && pwd)
+# shellcheck source=tests/testlib.sh
+. "${testdir}/testlib.sh"
+
+tmpdir=$(mktemp -d) # honors the Windows-shaped TMPDIR the MSYS suite exports
+cleanup() { rm -rf "$tmpdir"; }
+trap 'set +e; cleanup' EXIT
+trap 'set +e; cleanup; exit 1' HUP INT QUIT PIPE TERM
+
+# One local file header, no central directory: unzOpen fails, unzRepair
+# recovers the single entry. Same vector as -#test=zip-repair-shift.
+plant_damaged_cache() {
+    rm -rf "$1"
+    mkdir -p "$1/hts-cache"
+    printf '\120\113\003\004\024\000\000\000\000\000\000\000\000\000\000\000\350\212\000\000\000\000\000\000\000\000\001\000\000\000\141' \
+        >"$1/hts-cache/new.zip"
+}
+
+dead=http://127.0.0.1:1/
+
+# --- the CLI path (-#R), repair succeeding -----------------------------------
+printf '[-#R repairs in place] ..\t'
+proj="${tmpdir}/cli"
+plant_damaged_cache "$proj"
+out=$(httrack -O "$proj" -#R "$dead" 2>&1)
+grep -q 'successfully recovered' <<<"$out" || {
+    echo "FAIL: no recovery reported: $out"
+    exit 1
+}
+test ! -e "${proj}/hts-cache/repair.zip" || {
+    echo "FAIL: the recovery was left in repair.zip"
+    exit 1
+}
+test "$(wc -c <"${proj}/hts-cache/new.zip")" -gt 31 || {
+    echo "FAIL: new.zip is still the damaged one"
+    exit 1
+}
+echo "OK"
+
+# --- #824: nothing was recoverable, so nothing may be committed --------------
+printf '[-#R refuses an empty recovery] ..\t'
+proj="${tmpdir}/empty"
+rm -rf "$proj"
+mkdir -p "$proj/hts-cache"
+printf 'not a zip at all, some bytes' >"$proj/hts-cache/new.zip"
+rc=0
+out=$(httrack -O "$proj" -#R "$dead" 2>&1) || rc=$?
+test "$rc" -ne 0 || {
+    echo "FAIL: an empty recovery exited 0: $out"
+    exit 1
+}
+if grep -q 'successfully recovered' <<<"$out"; then
+    echo "FAIL: an empty recovery claimed success: $out"
+    exit 1
+fi
+test "$(wc -c <"${proj}/hts-cache/new.zip")" -eq 28 || {
+    echo "FAIL: the damaged cache was replaced by the empty recovery"
+    exit 1
+}
+echo "OK"
+
+if [ "$(uname -s)" != "Linux" ]; then
+    echo "repair-rename: 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 failure legs would pass vacuously.
+if [ ! -r "${RENAMEFAIL_LA:-}" ]; then
+    echo "repair-rename: ${RENAMEFAIL_LA:-\$RENAMEFAIL_LA} was not built" >&2
+    exit 1
+fi
+if grep -q "^dlname=''" "$RENAMEFAIL_LA"; then
+    echo "repair-rename: static-only build, skipping the interposed legs"
+    exit 0
+fi
+if [ ! -r "${RENAMEFAIL_LIB:-}" ]; then
+    echo "repair-rename: ${RENAMEFAIL_LIB:-\$RENAMEFAIL_LIB} was not built" >&2
+    exit 1
+fi
+
+# An LD_PRELOAD library loads ahead of the executable's own libasan, which ASan
+# refuses by default. The shim allocates nothing, so the ordering is harmless.
+export ASAN_OPTIONS="${ASAN_OPTIONS:+$ASAN_OPTIONS:}verify_asan_link_order=0"
+export RENAMEFAIL_MODE=repair
+export LD_PRELOAD="$RENAMEFAIL_LIB"
+
+# --- the CLI path, move refused ----------------------------------------------
+printf '[-#R reports a refused move] ..\t'
+proj="${tmpdir}/cli-fail"
+plant_damaged_cache "$proj"
+rc=0
+out=$(httrack -O "$proj" -#R "$dead" 2>&1) || rc=$?
+test "$rc" -ne 0 || {
+    echo "FAIL: a refused move exited 0: $out"
+    exit 1
+}
+if grep -q 'successfully recovered' <<<"$out"; then
+    echo "FAIL: a refused move still claimed success: $out"
+    exit 1
+fi
+test -s "${proj}/hts-cache/repair.zip" || {
+    echo "FAIL: the recovery was not kept for a retry"
+    exit 1
+}
+test "$(wc -c <"${proj}/hts-cache/new.zip")" -eq 31 || {
+    echo "FAIL: the damaged cache was destroyed anyway"
+    exit 1
+}
+echo "OK"
+
+# --- the engine path (cache_init), move refused ------------------------------
+printf '[cache_init reports a refused move] ..\t'
+proj="${tmpdir}/engine"
+plant_damaged_cache "$proj"
+httrack -O "$proj" "$dead" --timeout=2 --retries=0 -q >/dev/null 2>&1 || true
+log="${proj}/hts-log.txt"
+test -r "$log" || {
+    echo "FAIL: no crawl log"
+    exit 1
+}
+grep -q 'damaged cache' "$log" || {
+    echo "FAIL: the repair path never ran"
+    exit 1
+}
+grep -q 'could not put the repaired cache in place' "$log" || {
+    echo "FAIL: a refused move was not reported: $(grep -i cache "$log")"
+    exit 1
+}
+if grep -q 'successfully recovered' "$log"; then
+    echo "FAIL: a refused move still claimed success"
+    exit 1
+fi
+test -s "${proj}/hts-cache/repair.zip" || {
+    echo "FAIL: the recovery was not kept for a retry"
+    exit 1
+}
+echo "OK"
+
+# --- the move is refused the way Windows refuses it --------------------------
+# The destination always exists there, so every repair takes hts_rename_over()'s
+# fallback. Before #790 that fallback removed the cache and then failed.
+printf '[a refused fallback keeps the cache] ..\t'
+proj="${tmpdir}/eexist"
+plant_damaged_cache "$proj"
+rc=0
+out=$(RENAMEFAIL_MODE=repair-eexist httrack -O "$proj" -#R "$dead" 2>&1) || rc=$?
+test "$rc" -ne 0 || {
+    echo "FAIL: a refused fallback exited 0: $out"
+    exit 1
+}
+test "$(wc -c <"${proj}/hts-cache/new.zip")" -eq 31 || {
+    echo "FAIL: the fallback destroyed the cache"
+    exit 1
+}
+test -s "${proj}/hts-cache/repair.zip" || {
+    echo "FAIL: the recovery was not kept for a retry"
+    exit 1
+}
+leftover=$(find "${proj}/hts-cache" -name '*.hts-old*' | head -1)
+test -z "$leftover" || {
+    echo "FAIL: the parked copy was left behind: $leftover"
+    exit 1
+}
+echo "OK"

tests/107_local-bak-collision.test

@@ -0,0 +1,21 @@
+#!/bin/bash
+#
+# #774: the re-fetch backup lives in an hts-tmp directory beside the mirrored
+# file, so the site here serves that exact path. url_savename must escape the
+# reserved segment, landing the sibling in hts-tmp_ where the backup of a.bin
+# cannot consume it. Asserting the unescaped path instead would pass with the
+# bug live, which is how the first attempt at this test missed it.
+
+set -euo pipefail
+
+: "${top_srcdir:=..}"
+
+bash "$top_srcdir/tests/local-crawl.sh" \
+    --rerun-args '--update' \
+    --file-matches 'bakname/a.bin' 'BAKNAME-MAIN-V2' \
+    --file-matches 'bakname/hts-tmp_/a.bin.bak' 'BAKNAME-SIBLING' \
+    --file-min-bytes 'bakname/hts-tmp_/a.bin.bak' 2048 \
+    --not-found 'bakname/hts-tmp/a.bin.bak' \
+    --log-not-found 'could not back up' \
+    --log-not-found 'could not restore' \
+    httrack 'BASEURL/bakname/index.html'

tests/108_engine-refetch-backup.test

@@ -0,0 +1,25 @@
+#!/bin/bash
+#
+# Drives -#test=refetchbackup: the #77 re-fetch backup must leave a copy of the
+# resource whatever happens, and must not build its temporary name inside the
+# mirror namespace (#774, #775).
+
+set -euo pipefail
+
+dir=$(mktemp -d)
+trap 'set +e; rm -rf "$dir"' EXIT
+trap 'set +e; rm -rf "$dir"; exit 1' HUP INT QUIT PIPE TERM
+
+rc=0
+out=$(httrack -O /dev/null -#test=refetchbackup "$dir" 2>&1) || rc=$?
+if test "$rc" -ne 0 || ! grep -q "refetchbackup: OK" <<<"$out"; then
+    echo "FAIL (exit $rc): $out" >&2
+    exit 1
+fi
+
+# The temporaries live in hts-tmp and the last user removes it.
+leftovers=$(find "$dir" -mindepth 1 | head -5)
+test -z "$leftovers" || {
+    echo "FAIL: leftover temporaries: $leftovers" >&2
+    exit 1
+}

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/116_engine-rtrim.test

@@ -1,107 +0,0 @@
-#!/bin/bash
-#
-# Backward scans that start at s + strlen(s) - 1 and decrement with no lower
-# bound: the config-file right trim and the collision-rename digit scan both
-# walked off the front of a stack buffer. Neither ASan nor _FORTIFY_SOURCE sees
-# the self-test's overrun (it lands in the same frame), hence the poisoned byte.
-
-set -euo pipefail
-
-: "${top_srcdir:=..}"
-
-# Resolve httrack before any cd: PATH may carry a build-relative entry.
-bin=$(command -v httrack) || {
-    echo "FAIL: httrack not found on PATH" >&2
-    exit 1
-}
-case "$bin" in
-/*) ;;
-*) bin="$(cd "$(dirname "$bin")" && pwd)/$(basename "$bin")" ;;
-esac
-
-tmp=$(mktemp -d "${TMPDIR:-/tmp}/httrack_rtrim.XXXXXX") || exit 1
-trap 'set +e; rm -rf "$tmp"' EXIT
-trap 'rm -rf "$tmp"' HUP INT QUIT PIPE TERM
-
-fail() {
-    echo "FAIL: $1" >&2
-    exit 1
-}
-
-# --- 1. the helper itself ---------------------------------------------------
-out=$("$bin" -#test=rtrim) || fail "httrack -#test=rtrim exited non-zero: $out"
-test "$out" = "rtrim self-test: OK" || fail "expected 'rtrim self-test: OK', got: $out"
-
-# --- 2. collision rename over an all-digit name -----------------------------
-# Two pages with the same all-digit name save to 2024.html, so the second goes
-# through the -<n> rename and the digit scan has nothing but digits to walk
-# over. Driven twice, because the two routes differ in who picks the URLs.
-site="$tmp/site"
-mkdir -p "$site/a" "$site/b"
-printf '%s\n' '<html><body><a href="a/2024.html">a</a> <a href="b/2024.html">b</a></body></html>' \
-    >"$site/index.html"
-echo '<html><body>A</body></html>' >"$site/a/2024.html"
-echo '<html><body>B</body></html>' >"$site/b/2024.html"
-
-# -g flattens the tree, and pins depth to 0: the operator supplies both URLs.
-out1="$tmp/out1"
-mkdir -p "$out1"
-(cd "$out1" && "$bin" -g "file://$site/a/2024.html" "file://$site/b/2024.html" \
-    --quiet -n >.log 2>&1) || fail "collision crawl exited non-zero: $(tail -3 "$out1/.log")"
-
-test -f "$out1/2024.html" || fail "2024.html not mirrored"
-test -f "$out1/2024-2.html" || fail "colliding name was not renamed to 2024-2.html"
-
-# -N "%n.%t" collides the same way with depth unrestricted, so one starting URL
-# is enough and the crawled page picks both colliding names itself.
-out3="$tmp/out3"
-mkdir -p "$out3"
-(cd "$out3" && "$bin" "file://$site/index.html" -N "%n.%t" --quiet -n >.log 2>&1) ||
-    fail "userdef-savename crawl exited non-zero: $(tail -3 "$out3/.log")"
-test -f "$out3/2024.html" || fail "2024.html not mirrored under -N '%n.%t'"
-test -f "$out3/2024-2.html" ||
-    fail "colliding name was not renamed under -N '%n.%t' (links followed, not argv)"
-
-# The rename must keep counting, not restart: a third collision is -3.
-mkdir -p "$site/c"
-echo '<html><body>C</body></html>' >"$site/c/2024.html"
-out2="$tmp/out2"
-mkdir -p "$out2"
-(cd "$out2" && "$bin" -g "file://$site/a/2024.html" "file://$site/b/2024.html" \
-    "file://$site/c/2024.html" --quiet -n >.log 2>&1) ||
-    fail "three-way collision crawl exited non-zero: $(tail -3 "$out2/.log")"
-test -f "$out2/2024-3.html" || fail "third colliding name was not renamed to 2024-3.html"
-
-# --- 3. a blank config line is skipped, not parsed ---------------------------
-# HTS_HTTRACKRC is ".httrackrc" on POSIX and "httrackrc" on Windows.
-rcdir="$tmp/rc"
-mkdir -p "$rcdir"
-echo '<html><body>hi</body></html>' >"$rcdir/index.html"
-printf '   \nzzz-not-an-option\n' >"$rcdir/.httrackrc"
-cp "$rcdir/.httrackrc" "$rcdir/httrackrc"
-
-rc=0
-log=$( (cd "$rcdir" && "$bin" "file://$rcdir/index.html" --quiet -n 2>&1)) || rc=$?
-test "$rc" -eq 0 || fail "rc-file crawl exited $rc: $log"
-log=${log//$'\r'/} # the empty-option check below must not miss a CRLF line
-
-# The line after the blank one must still be read, or this proves nothing.
-case "$log" in
-*"Unknown option: zzz-not-an-option"*) ;;
-*) fail "config file was not parsed past the blank line: $log" ;;
-esac
-# The blank line itself must not become an empty option.
-case "$log" in
-*"Unknown option: "$'\n'*) fail "blank config line was parsed as an empty option: $log" ;;
-esac
-
-# --- 4. the call sites stay bounded -----------------------------------------
-# Sections 2 and 3 only go red under a sanitizer: on a plain build the byte
-# below the buffer is usually not a digit, so a reverted scan stops anyway and
-# produces the same names. Pin the two sites at the source instead.
-command grep -q 'hts_rtrim(line, HTS_REALSPACES)' "$top_srcdir/src/htsalias.c" ||
-    fail "htsalias.c right trim no longer goes through hts_rtrim"
-command grep -q 'hts_rtrimlen(tempo, "0123456789")' "$top_srcdir/src/htsname.c" ||
-    fail "htsname.c collision-suffix scan no longer goes through hts_rtrimlen"
-
-exit 0

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/61_webhttrack-locale.test

@@ -23,7 +23,7 @@ funcs=$(sed -n '/^function lang_index/,/^}/p' "${script}")
 # would truncate the lift and silently stop testing everything below it.
 grep -q '^# Find the browser' "${script}" || fail "locale block terminator moved in ${script}"
 block=$(sed -n '/^# Locale/,/^# Find the browser/p' "${script}" | sed '$d')
-echo "${block}" | grep -q 'LANGN=.*lang_index' || fail "could not lift the whole locale block from ${script}"
+grep -q 'LANGN=.*lang_index' <<<"${block}" || fail "could not lift the whole locale block from ${script}"
 
 # Run the lifted block against whatever locale vars the caller exported.
 run_block() {

tests/66_engine-port80-strip.test

@@ -9,4 +9,5 @@ set -euo pipefail
 # (#614) was stripped as if it were the default. The default is scheme-aware
 # (#638): an explicit :80 on https/ftp stays, :443/:21 strip under their own
 # scheme. All assertions live in the engine self-test.
-httrack -O /dev/null -#test=stripport | grep -q "stripport self-test OK"
+out=$(httrack -O /dev/null -#test=stripport)
+grep -q "stripport self-test OK" <<<"$out"

tests/72_watchdog-crawl.test

@@ -21,7 +21,7 @@ test "$rc" -ne 77 || {
     echo "SKIP: local crawl prerequisites missing" >&2
     exit 77
 }
-if printf '%s\n' "$out" | grep -q "could not discover server port"; then
+if grep -q "could not discover server port" <<<"$out"; then
     echo "SKIP: server port announce raced" >&2
     exit 77
 fi
@@ -30,7 +30,7 @@ fi
 # together they pin the fast exit on the 3s watchdog, not httrack giving up.
 test "$rc" -ne 0 || fail "stalled crawl reported success"
 test "$elapsed" -lt 25 || fail "watchdog fired late (${elapsed}s)"
-printf '%s\n' "$out" | grep -q "watchdog fired" ||
+grep -q "watchdog fired" <<<"$out" ||
     fail "crawl failed but not via the watchdog: $out"
 
 echo "crawl watchdog OK (reaped in ${elapsed}s)"

tests/80_engine-crash-symbolize.test

@@ -71,7 +71,8 @@ grep -qE 'st_strsafe|strcpy_safe_' "$oracle" || {
 # The payload. Dropping the raw frames first is what makes it specific: both
 # names are static, so .dynsym could never have carried them. Not anchored on
 # the "0xOFF:" line, the inline chain puts the name on either half.
-grep -v "$rawframe" "$out" | grep -qE 'st_strsafe|strcpy_safe_' || {
+symbolized=$(grep -v "$rawframe" "$out" || true)
+grep -qE 'st_strsafe|strcpy_safe_' <<<"$symbolized" || {
     echo "the handler did not name the hidden frames:" >&2
     cat "$out" >&2
     exit 1

tests/89_webhttrack-error-overflow.test

@@ -169,7 +169,8 @@ test "${written}" -lt "${#profile}" ||
     fail "the file-size limit did not stop the write (${written} bytes landed)"
 check_clipped "Unable to write ${#profile} bytes in the the init file " "${path}/p"
 
-get "${port}" /server/index.html | grep -q '200 OK' ||
+reply=$(get "${port}" /server/index.html || true)
+grep -q '200 OK' <<<"$reply" ||
     fail "the server stopped answering after the refused saves"
 
 echo "PASS"

tests/Makefile.am

@@ -227,6 +227,9 @@ TESTS = \
 	103_teardown-status.test \
 	104_engine-warc-longurl.test \
 	105_suite-timeout.test \
-	116_engine-rtrim.test
+	106_engine-repair-rename.test \
+	107_local-bak-collision.test \
+	108_engine-refetch-backup.test \
+	111_local-ftp-update-rest.test
 
 CLEANFILES = check-network_sh.cache

tests/local-crawl.sh

@@ -345,6 +345,7 @@ if test "${#plants[@]}" -gt 0; then
         if test "${plants[$i]}" = "--plant-dir"; then
             mkdir -p "$path" || die "could not create $path"
         else
+            mkdir -p "$(dirname "$path")" || die "could not create ${path%/*}"
             echo "$plant_poison" >"$path" || die "could not write $path"
         fi
         result "OK"
@@ -529,9 +530,25 @@ if test -n "$wacz_validate"; then
 fi
 
 # No crawl, even a cancelled one, may leave engine temporaries: .delayed (#107,
-# #483), or the .z/.u content-coding temps (#557).
+# #483), the .z/.u content-coding temps (#557), or the hts-tmp directory those
+# and the re-fetch backup live in (#774). Only a test that planted something in
+# hts-tmp itself owns what is left there, so only that case skips the scan.
 info "checking for leftover engine temporaries"
-leftovers=$(find "$out" \( -name '*.delayed' -o -name '*.z' -o -name '*.u' \) 2>/dev/null | head -5)
+scan_tmpdir=1
+i=0
+while test "$i" -lt "${#plants[@]}"; do
+    case "${plants[$((i + 1))]}" in
+    */hts-tmp/*) scan_tmpdir=0 ;;
+    esac
+    i=$((i + 2))
+done
+if test "$scan_tmpdir" -eq 1; then
+    leftovers=$(find "$out" \( -name '*.delayed' -o -name '*.z' -o -name '*.u' \
+        -o -name 'hts-tmp' \) 2>/dev/null | head -5)
+else
+    leftovers=$(find "$out" \( -name '*.delayed' -o -name '*.z' -o -name '*.u' \) \
+        2>/dev/null | head -5)
+fi
 if test -z "$leftovers"; then result "OK"; else
     result "leftover: $leftovers"
     exit 1

tests/local-server.py

@@ -1553,6 +1553,40 @@ class Handler(SimpleHTTPRequestHandler):
     def route_mini304_page(self):
         self.big_send(b"<html><body>tiny cacheable page</body></html>\n", "text/html")
 
+    # --- /bakname/: #774 — a mirrored file named like a re-fetch backup ----
+    # a.bin gets a new body every pass, so the update re-fetches it and takes a
+    # backup. The sibling carries a validator, so it only revalidates and must
+    # still be there afterwards. It is served under hts-tmp/, the directory the
+    # backup lives in, so the crawl asks for the exact path the engine writes.
+    BAKNAME_SIB = b"BAKNAME-SIBLING\n" + b"\x41\x42\x43\x44" * 512
+
+    def route_bakname_index(self):
+        self.send_html(
+            '\t<a href="a.bin">a</a>\n'
+            '\t<a href="hts-tmp/a.bin.bak">bak</a>\n'
+        )
+
+    def route_bakname_main(self):
+        v = 1 if self.refetch_pass() == 1 else 2
+        self.send_raw(
+            b"BAKNAME-MAIN-V%d\n" % v + b"\x31\x32\x33\x34" * 512,
+            "application/octet-stream",
+        )
+
+    def route_bakname_sibling(self):
+        if self.headers.get("If-Modified-Since") or self.headers.get("If-None-Match"):
+            self.send_response(304)
+            self.send_header("Content-Length", "0")
+            self.end_headers()
+            return
+        self.send_response(200)
+        self.send_header("Content-Type", "application/octet-stream")
+        self.send_header("Last-Modified", BIG_LASTMOD)
+        self.send_header("Content-Length", str(len(self.BAKNAME_SIB)))
+        self.end_headers()
+        if self.command != "HEAD":
+            self.wfile.write(self.BAKNAME_SIB)
+
     # --- /errmask/: issue #176 — a page that 200'd on the first crawl but 403s
     # on the update fetch must keep its good copy, not be overwritten nor purged.
     ERRMASK_GOOD = b"KEEP" + b"." * 1020  # 1024 B distinctive non-HTML body
@@ -2134,6 +2168,9 @@ class Handler(SimpleHTTPRequestHandler):
         "/redir/index.html": route_redir_index,
         "/redir/go.php": route_redir_go,
         "/redir/target.html": route_redir_target,
+        "/bakname/index.html": route_bakname_index,
+        "/bakname/a.bin": route_bakname_main,
+        "/bakname/hts-tmp/a.bin.bak": route_bakname_sibling,
         "/mini304/index.html": route_mini304_index,
         "/mini304/page.html": route_mini304_page,
         "/errmask/index.html": route_errmask_index,

tests/renamefail.c

@@ -1,7 +1,10 @@
-/* Borrows Windows' rename() for 01_engine-renameover.test, since POSIX cannot
-   reach hts_rename_over()'s unlink fallback: an existing target is refused with
+/* Borrows Windows' rename() for the tests POSIX cannot otherwise reach:
+   hts_rename_over()'s aside fallback needs an existing target refused with
    EEXIST, and RENAMEFAIL_MODE=locked reports EACCES instead, as the CRT does
-   for a source another process holds. */
+   for a source another process holds. =repair and =repair-eexist narrow the
+   refusal to the cache-repair move (#786), the latter through the fallback so
+   the retry inside it is the failing one. RENAMEFAIL_ASIDE_FAILS=N refuses the
+   first N moves back out of a parked ".hts-old" name (#790). */
 
 #define _GNU_SOURCE
 #include <dlfcn.h>
@@ -18,15 +21,32 @@ SHIM_EXPORT int rename(const char *oldpath, const char *newpath);
 
 SHIM_EXPORT int rename(const char *oldpath, const char *newpath) {
   static int (*real_rename)(const char *, const char *) = NULL;
+  static int aside_failures = 0;
   const char *const mode = getenv("RENAMEFAIL_MODE");
-  const int locked = mode != NULL && strcmp(mode, "locked") == 0;
+  const char *const aside_fails = getenv("RENAMEFAIL_ASIDE_FAILS");
+  const char *const slash = strrchr(oldpath, '/');
+  const char *const base = slash != NULL ? slash + 1 : oldpath;
+  const int repaired = strcmp(base, "repair.zip") == 0;
   struct stat st;
 
-  if (locked) {
+  if (mode != NULL && (strcmp(mode, "locked") == 0 ||
+                       (repaired && strcmp(mode, "repair") == 0))) {
     errno = EACCES;
     return -1;
   }
-  if (stat(newpath, &st) == 0) {
+  if (repaired && mode != NULL && strcmp(mode, "repair-eexist") == 0) {
+    errno = stat(newpath, &st) == 0 ? EEXIST : EACCES;
+    return -1;
+  }
+  if (aside_fails != NULL && strstr(base, ".hts-old") != NULL &&
+      aside_failures < atoi(aside_fails)) {
+    aside_failures++;
+    errno = EACCES;
+    return -1;
+  }
+  /* Only the bare shim emulates Windows for every rename; a narrowed mode
+     leaves the rest of the run on plain POSIX semantics. */
+  if (mode == NULL && aside_fails == NULL && stat(newpath, &st) == 0) {
     errno = EEXIST;
     return -1;
   }

tests/webhttrack-smoke.sh

@@ -53,13 +53,13 @@ echo "stub browser invoked with: \$1" >&2
 opturl="\${1%/}/server/option2.html"
 warcurl="\${1%/}/server/option9.html"
 smurl="\${1%/}/server/option8.html"
-if body="\$(curl -fsSL --max-time 20 "\$1")" && printf '%s' "\$body" | grep -qai httrack && printf '%s' "\$body" | grep -qaF step2.html &&
-    opt="\$(curl -fsSL --max-time 20 "\$opturl")" && printf '%s' "\$opt" | grep -qaF "title='" &&
-    printf '%s' "\$opt" | grep -qaF 'name="singlefile"' && printf '%s' "\$opt" | grep -qaF 'name="singlefilemax"' &&
-    ! printf '%s' "\$opt" | grep -qaF '\${LANG_SINGLEFILE}' &&
-    warc="\$(curl -fsSL --max-time 20 "\$warcurl")" && printf '%s' "\$warc" | grep -qaF 'name="warcfile"' && printf '%s' "\$warc" | grep -qaF WARC &&
-    printf '%s' "\$warc" | grep -qaF 'name="changes"' && printf '%s' "\$warc" | grep -qaF hts-changes.json &&
-    sm="\$(curl -fsSL --max-time 20 "\$smurl")" && printf '%s' "\$sm" | grep -qaF 'name="sitemapurl"' && printf '%s' "\$sm" | grep -qaF 'name="sitemap"'; then
+if body="\$(curl -fsSL --max-time 20 "\$1")" && grep -qai httrack <<<"\$body" && grep -qaF step2.html <<<"\$body" &&
+    opt="\$(curl -fsSL --max-time 20 "\$opturl")" && grep -qaF "title='" <<<"\$opt" &&
+    grep -qaF 'name="singlefile"' <<<"\$opt" && grep -qaF 'name="singlefilemax"' <<<"\$opt" &&
+    ! grep -qaF '\${LANG_SINGLEFILE}' <<<"\$opt" &&
+    warc="\$(curl -fsSL --max-time 20 "\$warcurl")" && grep -qaF 'name="warcfile"' <<<"\$warc" && grep -qaF WARC <<<"\$warc" &&
+    grep -qaF 'name="changes"' <<<"\$warc" && grep -qaF hts-changes.json <<<"\$warc" &&
+    sm="\$(curl -fsSL --max-time 20 "\$smurl")" && grep -qaF 'name="sitemapurl"' <<<"\$sm" && grep -qaF 'name="sitemap"' <<<"\$sm"; then
     echo PASS >"$marker"
 else
     echo "FAIL: unexpected response from \$1" >"$marker"