Export hts_convertStringSystemToUTF8 from the DLL

Mark the CP_ACP->UTF-8 converter HTSEXT_API, matching hts_argv_utf8 next to it, so WinHTTrack can call the engine's converter instead of keeping a private copy. Windows-only (inside the _WIN32 block), so no POSIX ABI change and no soname bump. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com> Signed-off-by: Xavier Roche <roche@httrack.com>
Let a failed connect fall back to the next address on Windows (#580 )
2026-07-15 13:21:14 +03:00 · 2026-07-15 07:32:09 +02:00 · 2026-07-15 07:20:44 +02:00 · 2026-07-14 20:03:40 +02:00 · 2026-07-14 19:49:39 +02:00 · 2026-07-14 17:58:39 +02:00
38 changed files with 1913 additions and 434 deletions
--- a/.gitattributes
+++ b/.gitattributes
@@ -1,3 +1,8 @@
 # Resource scripts are Windows tooling input and must stay CRLF: the engine has no
 # encoding guard, so an autocrlf checkout could otherwise flatten them silently.
 *.rc text eol=crlf
+
+# The test scripts run under Git Bash on the Windows CI; a CRLF checkout makes
+# bash die on $'\r' on every line of them.
+*.test text eol=lf
+*.sh text eol=lf
--- a/.github/workflows/windows-build.yml
+++ b/.github/workflows/windows-build.yml
@@ -119,22 +119,61 @@ jobs:
            throw "CRT mismatch across the boundary: libhttrack.dll=$a httrack.exe=$b"
          }

-      # The engine self-tests exercise the codecs the DLL was linked with: a
-      # missing brotli/zstd decoder shows up here, not just at link time.
-      - name: Run the content-coding self-tests
-        shell: pwsh
+      # The engine ships ~90 tests and none had ever run on Windows: "make check"
+      # is Linux/macOS only. These are the offline ones, driven from Git Bash
+      # against the native httrack.exe. They subsume the self-tests this step
+      # used to run inline (codecs, cache, fsize).
+      - name: Run the engine test suite (offline tests)
+        shell: bash
+        working-directory: tests
        run: |
-          $ErrorActionPreference = "Stop"
-          $exe = "src\${{ matrix.platform }}\${{ matrix.configuration }}\httrack.exe"
-          $tmp = New-Item -ItemType Directory -Path (Join-Path $env:RUNNER_TEMP "st")
-          foreach ($t in @("acceptencoding", "contentcodings")) {
-            $out = & $exe -O NUL "-#test=$t" $tmp.FullName run
-            if ($LASTEXITCODE -ne 0) { throw "$t failed" }
-            if (-not ($out | Select-String -SimpleMatch "$t self-test OK")) {
-              throw "$t did not report OK: $out"
-            }
-            Write-Host ($out -join "`n")
-          }
+          set -u
+          bin="$(cygpath -u "$GITHUB_WORKSPACE")/src/${{ matrix.platform }}/${{ matrix.configuration }}"
+          export PATH="$bin:$PATH"
+          command -v httrack >/dev/null || { echo "::error::no httrack.exe in $bin"; exit 1; }
+
+          # httrack.exe is native, so MSYS rewrites any argument shaped like a
+          # POSIX path, and a URL path is shaped exactly like one: "/a/b.html"
+          # reached the engine as "C:/Program Files/Git/a/b.html". Switch that
+          # off, and hand the tests a TMPDIR that is already a Windows path.
+          export MSYS_NO_PATHCONV=1
+          export MSYS2_ARG_CONV_EXCL='*'
+          TMPDIR="$(cygpath -m "$RUNNER_TEMP")"
+          export TMPDIR
+
+          pass=0 fail=0 skip=0 failed=""
+          for t in 00_runnable.test 01_engine-*.test 01_zlib-*.test; do
+            rc=0
+            bash "$t" >"$t.log" 2>&1 || rc=$?
+            case "$rc" in
+              0) pass=$((pass + 1)); echo "PASS $t" ;;
+              77) skip=$((skip + 1)); echo "SKIP $t" ;;
+              *)
+                fail=$((fail + 1)) failed="$failed $t"
+                echo "FAIL $t (exit $rc)"
+                # These assert with `test "$(...)" == "..." || exit 1`, which
+                # says nothing at all on failure. Re-run traced.
+                bash -x "$t" >>"$t.log" 2>&1 || true
+                tail -n 25 "$t.log" | sed 's/^/      /'
+                ;;
+            esac
+          done
+          echo "ran=$((pass + fail + skip)) pass=$pass fail=$fail skip=$skip" |
+            tee -a "$GITHUB_STEP_SUMMARY"
+
+          # Every gate in these scripts exits 77, so a suite that degraded to
+          # all-skipped would report green having tested nothing: assert a floor
+          # on what actually ran, not just the absence of failures.
+          [ "$pass" -ge 45 ] || { echo "::error::only $pass tests passed ($skip skipped)"; exit 1; }
+          [ "$fail" -eq 0 ] || { echo "::error::failing:$failed"; exit 1; }
+
+      - name: Upload the test logs
+        if: always()
+        uses: actions/upload-artifact@v4
+        with:
+          name: engine-tests-${{ matrix.platform }}-${{ matrix.configuration }}
+          path: tests/*.log
+          if-no-files-found: warn

      - name: Upload MSBuild logs
        if: always()
--- a/man/httrack.1
+++ b/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 "12 July 2026" "httrack website copier"
+.TH httrack 1 "14 July 2026" "httrack website copier"
 .SH NAME
 httrack \- offline browser : copy websites to a local directory
 .SH SYNOPSIS
@@ -135,7 +135,7 @@ continue an interrupted mirror using the cache (\-\-continue)
 mirror ALL links located in the first level pages (mirror links) (\-\-mirrorlinks)
 .SS Proxy options:
 .IP \-P
-proxy use (\-P proxy:port or \-P user:pass@proxy:port) (\-\-proxy <param>)
+proxy use (\-P [socks5://][user:pass@]proxy:port) (\-\-proxy <param>)
 .IP \-%f
 *use proxy for ftp (f0 don't use) (\-\-httpproxy\-ftp[=N])
 .IP \-%b
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -61,7 +61,7 @@ libhttrack_la_SOURCES =  htscore.c htsparse.c htsback.c htscache.c \
 	htshelp.c htslib.c htscoremain.c \
 	htsname.c htsrobots.c htstools.c htswizard.c \
 	htsalias.c htsthread.c htsindex.c htsbauth.c \
-	htsmd5.c htscodec.c htszlib.c htswrap.c htsconcat.c \
+	htsmd5.c htscodec.c htsproxy.c htszlib.c htswrap.c htsconcat.c \
 	htsmodules.c htscharset.c punycode.c htsencoding.c htssniff.c \
 	md5.c \
 	minizip/ioapi.c minizip/mztools.c minizip/unzip.c minizip/zip.c \
@@ -72,7 +72,7 @@ libhttrack_la_SOURCES =  htscore.c htsparse.c htsback.c htscache.c \
 	htshelp.h htsindex.h htslib.h htsmd5.h \
 	htsmodules.h htsname.h htsnet.h htssniff.h \
 	htsopt.h htsrobots.h htsthread.h  \
-	htstools.h htswizard.h htswrap.h htscodec.h htszlib.h  \
+	htstools.h htswizard.h htswrap.h htscodec.h htsproxy.h htszlib.h  \
 	htsstrings.h htsarrays.h httrack-library.h \
 	htscharset.h punycode.h htsencoding.h \
 	htsentities.h htsentities.sh htsbasiccharsets.sh htscodepages.h \
--- a/src/htsback.c
+++ b/src/htsback.c
@@ -45,6 +45,7 @@ Please visit our Website: http://www.httrack.com

 #include "htsftp.h"
 #include "htscodec.h"
+#include "htsproxy.h"
 #if HTS_USEZLIB
 #include "htszlib.h"
 #else
@@ -139,8 +140,9 @@ int back_connect_fallback_due(int addr_index, int addr_count, int elapsed,

 /* Pending-connect result for a non-blocking socket reported ready by select():
   0 = connected, >0 = the connect errno (refused, unreachable, ...), -1 if the
-   probe itself failed. A failed connect is reported writable too, so this is
-   how success is told from failure without blocking. */
+   probe itself failed. A failed connect is reported ready as well (writable on
+   posix, exception set on winsock), so this is how success is told from failure
+   without blocking. */
 static int connect_socket_error(T_SOC soc) {
  int soerr = 0;
  socklen_t len = (socklen_t) sizeof(soerr);
@@ -775,7 +777,7 @@ int back_finalize(httrackp * opt, cache_back * cache, struct_back * sback,
        if (back[p].r.statuscode == HTTP_OK) {  // OK (ou 304 en backing)
          if (back[p].r.is_write) {     // Written file
            if (may_be_hypertext_mime(opt, back[p].r.contenttype, back[p].url_fil)) {   // to parse!
-              off_t sz;
+              LLint sz;

              sz = fsize_utf8(back[p].url_sav);
              if (sz > 0) {     // ok, exists!
@@ -1952,7 +1954,7 @@ int back_add(struct_back * sback, httrackp * opt, cache_back * cache, const char
      /* Not in cache ; maybe in temporary cache ? Warning: non-movable
         "url_sav" */
      else if (back_unserialize_ref(opt, adr, fil, &itemback) == 0) {
-        const off_t file_size = fsize_utf8(itemback->url_sav);
+        const LLint file_size = fsize_utf8(itemback->url_sav);

        /* Found file on disk */
        if (file_size > 0) {
@@ -1987,7 +1989,7 @@ int back_add(struct_back * sback, httrackp * opt, cache_back * cache, const char
      }
      /* Not in cache or temporary cache ; found on disk ? (hack) */
      else if (fexist_utf8(save)) {
-        const off_t sz = fsize_utf8(save);
+        const LLint sz = fsize_utf8(save);

        // Bon, là il est possible que le fichier ait été partiellement transféré
        // (s'il l'avait été en totalité il aurait été inscrit dans le cache ET existerait sur disque)
@@ -2111,6 +2113,17 @@ int back_add(struct_back * sback, httrackp * opt, cache_back * cache, const char
                        "error: forbidden test with ftp link for back_add");
          return -1;            // erreur pas de test permis
        }
+        // the ftp client dials the origin itself: over socks that would bypass
+        // the proxy, so fail the link rather than leak the connection (#563)
+        if (back[p].r.req.proxy.active &&
+            hts_proxy_is_socks(back[p].r.req.proxy.name)) {
+          back[p].r.statuscode = STATUSCODE_NON_FATAL;
+          strcpybuff(back[p].r.msg,
+                     "ftp:// is not supported over a SOCKS proxy");
+          back[p].status = STATUS_READY;
+          back_set_finished(sback, p);
+          return 0;
+        }
        if (!(back[p].r.req.proxy.active && opt->ftp_proxy)) {  // connexion directe, gérée en thread
          FTPDownloadStruct *str =
            (FTPDownloadStruct *) malloc(sizeof(FTPDownloadStruct));
@@ -2646,7 +2659,9 @@ void back_wait(struct_back * sback, httrackp * opt, cache_back * cache,
    for (i_mod = 0; i_mod < (unsigned int) back_max; i_mod++) {
      unsigned int i = (i_mod + mod_random) % (back_max);

-      if (back[i].status > 0) {
+      // winsock flags a failed connect in the exception set only: leave a
+      // connecting slot to the connect handler, which can still fall back
+      if (back[i].status > 0 && back[i].status != STATUS_CONNECTING) {
        if (!back[i].r.is_file) {       // not file..
          if (back[i].r.soc != INVALID_SOCKET) {        // hey, you never know..
            int err = FD_ISSET(back[i].r.soc, &fds_e);
@@ -2660,10 +2675,7 @@ void back_wait(struct_back * sback, httrackp * opt, cache_back * cache,
              }
              back[i].r.soc = INVALID_SOCKET;
              back[i].r.statuscode = STATUSCODE_CONNERROR;
-              if (back[i].status == STATUS_CONNECTING)
-                strcpybuff(back[i].r.msg, "Connect Error");
-              else
-                strcpybuff(back[i].r.msg, "Receive Error");
+              strcpybuff(back[i].r.msg, "Receive Error");
              if (back[i].status == STATUS_ALIVE) {     /* Keep-alive socket */
                back_delete(opt, cache, sback, i);
              } else {
@@ -2696,10 +2708,11 @@ void back_wait(struct_back * sback, httrackp * opt, cache_back * cache,
            gestion_timeout = 1;

        // connecté?
-        dispo = FD_ISSET(back[i].r.soc, &fds_c);
+        dispo = back[i].r.soc != INVALID_SOCKET &&
+                (FD_ISSET(back[i].r.soc, &fds_c) ||
+                 FD_ISSET(back[i].r.soc, &fds_e));
        if (dispo) { // socket ready: connect() finished (ok or failed)
-          // a refused/failed connect is reported writable too; probe SO_ERROR
-          // and, on failure, fall back to the next address (or fail the slot)
+          // probe SO_ERROR and, on failure, fall back to the next address
          if (connect_socket_error(back[i].r.soc) != 0) {
            if (!back_connect_next(opt, sback, i)) {
              deletehttp(&back[i].r);
@@ -2713,13 +2726,40 @@ void back_wait(struct_back * sback, httrackp * opt, cache_back * cache,
          }
          busy_state = 1;

+          // socks5: tunnel to the origin before anything is written, for http
+          // as well as https. Skip on a reused keep-alive socket (already
+          // tunneled) and on the post-TLS re-entry (ssl_con set) (#563).
+          if (back[i].r.req.proxy.active &&
+              hts_proxy_is_socks(back[i].r.req.proxy.name) &&
+              !back[i].r.keep_alive
+#if HTS_USEOPENSSL
+              && back[i].r.ssl_con == NULL
+#endif
+          ) {
+            const int timeout = back[i].timeout > 0 ? back[i].timeout : 30;
+
+            if (!socks5_handshake(opt, &back[i].r, back[i].url_adr, timeout)) {
+              if (!strnotempty(back[i].r.msg))
+                strcpybuff(back[i].r.msg, "SOCKS5 handshake failed");
+              deletehttp(&back[i].r);
+              back[i].r.soc = INVALID_SOCKET;
+              back[i].r.statuscode = STATUSCODE_NON_FATAL;
+              back[i].status = STATUS_READY;
+              back_set_finished(sback, i);
+              continue;
+            }
+          }
+
 #if HTS_USEOPENSSL
          /* SSL mode */
          if (back[i].r.ssl) {
            int tunnel_ok = 1;

-            // https via proxy: CONNECT-tunnel before TLS (#85)
-            if (back[i].r.req.proxy.active && back[i].r.ssl_con == NULL) {
+            // https via an http proxy: CONNECT-tunnel before TLS (#85); socks
+            // already carries the origin connection
+            if (back[i].r.req.proxy.active &&
+                !hts_proxy_is_socks(back[i].r.req.proxy.name) &&
+                back[i].r.ssl_con == NULL) {
              const int timeout = back[i].timeout > 0 ? back[i].timeout : 30;

              tunnel_ok =
@@ -3656,7 +3696,7 @@ void back_wait(struct_back * sback, httrackp * opt, cache_back * cache,
                      if (back[i].r.statuscode == HTTP_OK && !back[i].testmode) {       // 'OK'
                        if (!is_hypertext_mime(opt, back[i].r.contenttype, back[i].url_fil)) {  // not HTML
                          if (strnotempty(back[i].url_sav)) {   // target found
-                            off_t size = fsize_utf8(back[i].url_sav);
+                            LLint size = fsize_utf8(back[i].url_sav);

                            if (size >= 0) {
                              if (back[i].r.totalsize == size) {        // same size!
@@ -3875,7 +3915,7 @@ void back_wait(struct_back * sback, httrackp * opt, cache_back * cache,
                    // traiter 206 (partial content)
                    // xxc SI CHUNK VERIFIER QUE CA MARCHE??
                    if (back[i].r.statuscode == 206) {  // on nous envoie un morceau (la fin) coz une partie sur disque!
-                      off_t sz = fsize_utf8(back[i].url_sav);
+                      LLint sz = fsize_utf8(back[i].url_sav);
                      /* RFC 7233: resume at the server's Content-Range start,
                         not the offset we requested; a server may resume
                         earlier and appending the overlap duplicates bytes
--- a/src/htscache.c
+++ b/src/htscache.c
@@ -356,7 +356,7 @@ void cache_add(httrackp * opt, cache_back * cache, const htsblk * r,
      FILE *fp;

      // On recopie le fichier->.
-      off_t file_size = fsize_utf8(fconv(catbuff, sizeof(catbuff), url_save));
+      LLint file_size = fsize_utf8(fconv(catbuff, sizeof(catbuff), url_save));

      if (file_size >= 0) {
        fp = FOPEN(fconv(catbuff, sizeof(catbuff), url_save), "rb");
@@ -1241,23 +1241,27 @@ char *readfile(const char *fil) {
 char *readfile2(const char *fil, LLint * size) {
  char *adr = NULL;
  char catbuff[CATBUFF_SIZE];
-  INTsys len = 0;
+  const LLint len = fsize(fil);

-  len = fsize(fil);
-  if (len >= 0) {               // exists
+  /* a size too large for size_t (32-bit Windows/i386) must fail closed: it
+     would wrap malloct() short while fread() still read the untruncated len */
+  const size_t buflen = len >= 0 ? llint_to_size_t(len) : (size_t) -1;
+
+  if (buflen != (size_t) -1) { // exists, and is addressable
    FILE *fp;

    fp = fopen(fconv(catbuff, sizeof(catbuff), fil), "rb");
    if (fp != NULL) {           // n'existe pas (!)
-      adr = (char *) malloct(len + 1);
+      adr = (char *) malloct(buflen + 1);
      if (size != NULL)
        *size = len;
      if (adr != NULL) {
-        if (len > 0 && fread(adr, 1, len, fp) != len) { // fichier endommagé ?
+        if (buflen > 0 &&
+            fread(adr, 1, buflen, fp) != buflen) { // fichier endommagé ?
          freet(adr);
          adr = NULL;
        } else
-          *(adr + len) = '\0';
+          *(adr + buflen) = '\0';
      }
      fclose(fp);
    }
@@ -1269,19 +1273,21 @@ char *readfile2(const char *fil, LLint * size) {
 char *readfile_utf8(const char *fil) {
  char *adr = NULL;
  char catbuff[CATBUFF_SIZE];
-  const off_t len = fsize_utf8(fil);
+  const LLint len = fsize_utf8(fil);
+  const size_t buflen = len >= 0 ? llint_to_size_t(len) : (size_t) -1;

-  if (len >= 0) {               // exists
+  if (buflen != (size_t) -1) { // exists, and is addressable (see readfile2)
    FILE *const fp = FOPEN(fconv(catbuff, sizeof(catbuff), fil), "rb");

    if (fp != NULL) {           // n'existe pas (!)
-      adr = (char *) malloct(len + 1);
+      adr = (char *) malloct(buflen + 1);
      if (adr != NULL) {
-        if (len > 0 && fread(adr, 1, len, fp) != len) { // fichier endommagé ?
+        if (buflen > 0 &&
+            fread(adr, 1, buflen, fp) != buflen) { // fichier endommagé ?
          freet(adr);
          adr = NULL;
        } else {
-          adr[len] = '\0';
+          adr[buflen] = '\0';
        }
      }
      fclose(fp);
--- a/src/htscache_selftest.c
+++ b/src/htscache_selftest.c
@@ -232,11 +232,10 @@ static int disk_fallback_selftest(httrackp *opt) {
  static const char body[] = "BINARY-on-disk-body-0123456789-no-trailing-nul";
  const size_t body_len = sizeof(body) - 1;

-  /* X-Save must start with path_html_utf8 so the reader resolves it verbatim
-     (otherwise it re-roots it as a pre-3.40 relative path); then the body we
-     create at fconv(save) is exactly where cache_readex looks for it. */
-  fconcat(save, sizeof(save), StringBuff(opt->path_html_utf8),
-          "example.com/blob.bin");
+  /* a DOS-ified X-Save loses the path_html_utf8 prefix the reader matches on,
+     and gets re-rooted as a pre-3.40 relative path; fconv() only on access */
+  concat(save, sizeof(save), StringBuff(opt->path_html_utf8),
+         "example.com/blob.bin");

  /* write only the header (X-In-Cache: 0); the body stays on disk */
  selftest_open_for_write(&cache, opt);
@@ -939,9 +938,9 @@ static void reconcile_put(httrackp *opt, const char *name, size_t size) {
 }

 /* Expect `name` to weigh `size` bytes, or be absent when size == -1. */
-static int reconcile_expect(httrackp *opt, const char *name, off_t size,
+static int reconcile_expect(httrackp *opt, const char *name, LLint size,
                            const char *what) {
-  const off_t got = fsize(reconcile_st_path(opt, name));
+  const LLint got = fsize(reconcile_st_path(opt, name));

  if (got != size) {
    fprintf(stderr, "cache-reconcile: %s: %s is %d bytes, expected %d\n", what,
@@ -955,7 +954,7 @@ int cache_reconcile_selftest(httrackp *opt, const char *dir) {
  int failures = 0;

  /* around the interrupted-run thresholds (new < 32768, old > 65536) */
-  static const off_t TINY = 1024, MID = 40000, SOLID = 131072;
+  static const LLint TINY = 1024, MID = 40000, SOLID = 131072;

  golden_setup(opt, dir);
 #ifdef _WIN32
@@ -1253,8 +1252,9 @@ static void corrupt_build_disk(httrackp *opt) {
  memset(corrupt_body_a, 'a', sizeof(corrupt_body_a) - 1);
  remove(reconcile_st_path(opt, "hts-cache/new.zip"));
  remove(reconcile_st_path(opt, "hts-cache/old.zip"));
-  fconcat(save, sizeof(save), StringBuff(opt->path_html_utf8),
-          CORRUPT_ADR "/victim.bin");
+  /* X-Save stored verbatim: see disk_fallback_selftest */
+  concat(save, sizeof(save), StringBuff(opt->path_html_utf8),
+         CORRUPT_ADR "/victim.bin");
  selftest_open_for_write(&cache, opt);
  store_entry(opt, &cache, CORRUPT_ADR, "/canary.html", "canary.html", 200,
              "OK", "text/html", "utf-8", "", "", "", "", corrupt_body_a,
--- a/src/htscharset.c
+++ b/src/htscharset.c
@@ -31,6 +31,9 @@ Please visit our Website: http://www.httrack.com
 /* ------------------------------------------------------------ */

 #include "htscharset.h"
+#ifdef _WIN32
+#include <shellapi.h>
+#endif
 #include "htsbase.h"
 #include "punycode.h"
 #include "htssafe.h"
@@ -382,10 +385,44 @@ char *hts_convertStringFromUTF8(const char *s, size_t size, const char *charset)
  return hts_convertStringCPFromUTF8(s, size, cp);
 }

-char *hts_convertStringSystemToUTF8(const char *s, size_t size) {
+HTSEXT_API char *hts_convertStringSystemToUTF8(const char *s, size_t size) {
  return hts_convertStringCPToUTF8(s, size, GetACP());
 }

+HTSEXT_API void hts_argv_utf8(int *pargc, char ***pargv) {
+  int wargc = 0;
+  LPWSTR *const wargv = CommandLineToArgvW(GetCommandLineW(), &wargc);
+  char **argv;
+  int i;
+
+  // On any failure keep the CRT's ANSI argv: lossy, but never half-converted.
+  if (wargv == NULL)
+    return;
+  if (wargc <= 0 ||
+      (argv = calloct((size_t) wargc + 1, sizeof(char *))) == NULL) {
+    LocalFree(wargv);
+    return;
+  }
+  for (i = 0; i < wargc; i++) {
+    const int wsize = (int) wcslen(wargv[i]);
+
+    // hts_convertUCS2StringToUTF8() returns NULL on an empty string
+    argv[i] =
+        wsize != 0 ? hts_convertUCS2StringToUTF8(wargv[i], wsize) : strdupt("");
+    if (argv[i] == NULL) {
+      while (i-- != 0)
+        freet(argv[i]);
+      freet(argv);
+      LocalFree(wargv);
+      return;
+    }
+  }
+  argv[wargc] = NULL; // callers may rely on argv[argc] == NULL
+  LocalFree(wargv);
+  *pargc = wargc;
+  *pargv = argv; // never freed: argv lives for the process
+}
+
 #else

 #include <errno.h>
--- a/src/htscharset.h
+++ b/src/htscharset.h
@@ -34,6 +34,7 @@ Please visit our Website: http://www.httrack.com
 #define HTS_CHARSET_DEFH

 /** Standard includes. **/
+#include "htsglobal.h"
 #include <stdlib.h>
 #include <string.h>
 #ifdef _WIN32
@@ -174,7 +175,16 @@ extern char *hts_convertUCS2StringToUTF8(LPWSTR woutput, int wsize);
 * Convert current system codepage to UTF-8.
 * This function is WIN32 specific.
 **/
-extern char *hts_convertStringSystemToUTF8(const char *s, size_t size);
+HTSEXT_API char *hts_convertStringSystemToUTF8(const char *s, size_t size);
+
+/**
+ * Replace the CRT's ANSI argv by a UTF-8 one decoded from the real UTF-16
+ * command line: every char* is UTF-8 on Windows (FOPEN, STAT, ... convert at
+ * the syscall boundary). Keeps the CRT's argv on failure; the new array is
+ * writable, NULL-terminated, and lives for the process.
+ * This function is WIN32 specific.
+ **/
+HTSEXT_API void hts_argv_utf8(int *pargc, char ***pargv);
 #endif

 #endif
--- a/src/htscore.c
+++ b/src/htscore.c
@@ -855,7 +855,7 @@ int httpmirror(char *url1, httrackp * opt) {
      char *filelist_buff = NULL;
      size_t filelist_sz = 0;
      const char *filelist_err = NULL; /* failure reason, NULL on success */
-      const off_t fs = fsize(StringBuff(opt->filelist));
+      const LLint fs = fsize(StringBuff(opt->filelist));

      if (fs < 0) {
        /* fsize() hides the cause; redo stat() for a precise errno (#49) */
@@ -863,7 +863,7 @@ int httpmirror(char *url1, httrackp * opt) {
        filelist_err = stat(StringBuff(opt->filelist), &st) != 0
                           ? strerror(errno)
                           : "not a regular file";
-      } else if ((filelist_sz = off_t_to_size_t(fs)) == (size_t) -1) {
+      } else if ((filelist_sz = llint_to_size_t(fs)) == (size_t) -1) {
        filelist_err = "file too large";
        filelist_sz = 0;
      } else {
@@ -2089,10 +2089,9 @@ int httpmirror(char *url1, httrackp * opt) {
              (OPT_GET_BUFF(opt), OPT_GET_BUFF_SIZE(opt), StringBuff(opt->path_log),
               "hts-cache/old.lst"), "rb");
      if (old_lst) {
-        const size_t sz =
-          off_t_to_size_t(fsize(fconcat
-                (OPT_GET_BUFF(opt), OPT_GET_BUFF_SIZE(opt), StringBuff(opt->path_log),
-                 "hts-cache/new.lst")));
+        const size_t sz = llint_to_size_t(
+            fsize(fconcat(OPT_GET_BUFF(opt), OPT_GET_BUFF_SIZE(opt),
+                          StringBuff(opt->path_log), "hts-cache/new.lst")));
        new_lst =
          fopen(fconcat
                (OPT_GET_BUFF(opt), OPT_GET_BUFF_SIZE(opt), StringBuff(opt->path_log),
--- a/src/htscoremain.c
+++ b/src/htscoremain.c
@@ -1509,7 +1509,7 @@ static int hts_main_internal(int argc, char **argv, httrackp * opt) {
                  htsmain_free();
                  return -1;
                } else {
-                  off_t fz;
+                  LLint fz;

                  na++;
                  fz = fsize(argv[na]);
@@ -2584,21 +2584,11 @@ static int hts_main_internal(int argc, char **argv, httrackp * opt) {
                hts_get_version_info(opt), t, url);
        fprintf(opt->log, "(");
        for(i = 0; i < argc; i++) {
-#ifdef _WIN32
-          char *carg =
-            hts_convertStringSystemToUTF8(argv[i], (int) strlen(argv[i]));
-          char *arg = carg != NULL ? carg : argv[i];
-#else
-          const char *arg = argv[i];
-#endif
+          const char *arg = argv[i]; // already UTF-8 on every platform
          if (strchr(arg, ' ') == NULL || strchr(arg, '\"') != NULL)
            fprintf(opt->log, "%s ", arg);
          else                  // entre "" (si espace(s) et pas déja de ")
            fprintf(opt->log, "\"%s\" ", arg);
-#ifdef _WIN32
-          if (carg != NULL)
-            free(carg);
-#endif
        }
        fprintf(opt->log, ")" LF);
        fprintf(opt->log, LF);
--- a/src/htsfilters.c
+++ b/src/htsfilters.c
@@ -122,8 +122,11 @@ int fa_strjoker_dual(int type, char **filters, int nfil, const char *nom1,
 }

 /* Real filters/URLs fit HTS_URLMAXSIZE*2; past it a hostile pattern recurses
-   O(len) deep or runs O(n^2*stars). Cap length (depth) and steps (work). */
+   O(len) deep or runs O(n^2*stars). Cap length, recursion depth and steps
+   (work): the length cap alone still allows ~2000 frames, ~900KB of stack,
+   which overflows the 1MB a Windows thread gets (#574). */
 #define STRJOKER_MAXLEN (HTS_URLMAXSIZE * 2)
+#define STRJOKER_MAXDEPTH 256u
 #define STRJOKER_MAXSTEPS 2000000u

 /* Failure memo for the recursive matcher: one bit per (chaine, joker) offset
@@ -133,20 +136,28 @@ typedef struct strjoker_memo {
  size_t stride;                /* strlen(joker0) + 1 */
  unsigned char *failed;        /* failed-pair bitmap; NULL: no memo */
  size_t *nsteps; /* shared work counter; NULL: unbounded (oracle) */
+  size_t maxdepth; /* deepest recursion reached */
+  hts_boolean cut; /* a branch hit the depth cap: its failures are not final */
 } strjoker_memo;

-static const char *strjoker_impl(const strjoker_memo *memo, const char *chaine,
-                                 const char *joker, LLint *size,
-                                 int *size_flag);
+static const char *strjoker_impl(strjoker_memo *memo, const char *chaine,
+                                 const char *joker, LLint *size, int *size_flag,
+                                 size_t depth);

 /* A pair that failed once fails forever (*size is only written on the success
   path), so record NULL results and cut the re-exploration. */
-static const char *strjoker_rec(const strjoker_memo *memo, const char *chaine,
-                                const char *joker, LLint *size,
-                                int *size_flag) {
+static const char *strjoker_rec(strjoker_memo *memo, const char *chaine,
+                                const char *joker, LLint *size, int *size_flag,
+                                size_t depth) {
  size_t bit = 0;
  const char *adr;

+  if (depth > memo->maxdepth)
+    memo->maxdepth = depth;
+  if (depth >= STRJOKER_MAXDEPTH) {
+    memo->cut = HTS_TRUE;
+    return NULL; /* nesting beyond any real filter: fail the branch safely */
+  }
  if (memo->nsteps != NULL && ++*memo->nsteps > STRJOKER_MAXSTEPS)
    return NULL; /* work budget spent: fail the match safely */
  if (memo->failed) {
@@ -155,8 +166,9 @@ static const char *strjoker_rec(const strjoker_memo *memo, const char *chaine,
    if (memo->failed[bit >> 3] & (unsigned char) (1u << (bit & 7)))
      return NULL;
  }
-  adr = strjoker_impl(memo, chaine, joker, size, size_flag);
-  if (adr == NULL && memo->failed)
+  adr = strjoker_impl(memo, chaine, joker, size, size_flag, depth + 1);
+  /* a cut branch may fail here yet match when reached at a shallower depth */
+  if (adr == NULL && memo->failed && !memo->cut)
    memo->failed[bit >> 3] |= (unsigned char) (1u << (bit & 7));
  return adr;
 }
@@ -164,13 +176,15 @@ static const char *strjoker_rec(const strjoker_memo *memo, const char *chaine,
 /* Match chaine against joker with a shared work budget *nsteps (a strjokerfind
   sweep passes one counter, bounding the whole scan). */
 static const char *strjoker_bounded(const char *chaine, const char *joker,
-                                    LLint *size, int *size_flag,
-                                    size_t *nsteps) {
-  strjoker_memo memo = {chaine, joker, 0, NULL, nsteps};
+                                    LLint *size, int *size_flag, size_t *nsteps,
+                                    size_t *maxdepth) {
+  strjoker_memo memo = {chaine, joker, 0, NULL, nsteps, 0, HTS_FALSE};
  unsigned char stackbits[2048];
  hts_boolean onheap = HTS_FALSE;
  const char *adr;

+  if (maxdepth != NULL)
+    *maxdepth = 0;
  if (chaine != NULL && joker != NULL) {
    const size_t l1 = strlen(chaine), l2 = strlen(joker);

@@ -189,9 +203,11 @@ static const char *strjoker_bounded(const char *chaine, const char *joker,
      }
    }
  }
-  adr = strjoker_rec(&memo, chaine, joker, size, size_flag);
+  adr = strjoker_rec(&memo, chaine, joker, size, size_flag, 0);
  if (onheap)
    freet(memo.failed);
+  if (maxdepth != NULL)
+    *maxdepth = memo.maxdepth;
  return adr;
 }

@@ -202,34 +218,39 @@ HTS_INLINE const char *strjoker(const char *chaine, const char *joker,
                                LLint *size, int *size_flag) {
  size_t nsteps = 0;

-  return strjoker_bounded(chaine, joker, size, size_flag, &nsteps);
+  return strjoker_bounded(chaine, joker, size, size_flag, &nsteps, NULL);
 }

 /* Test-only oracle: the same matcher without the failure memo. */
 const char *strjoker_nomemo(const char *chaine, const char *joker, LLint *size,
                            int *size_flag) {
-  const strjoker_memo memo = {chaine, joker, 0, NULL};
+  strjoker_memo memo = {chaine, joker, 0, NULL, NULL, 0, HTS_FALSE};

-  return strjoker_rec(&memo, chaine, joker, size, size_flag);
+  return strjoker_rec(&memo, chaine, joker, size, size_flag, 0);
 }

-/* Test-only: strjoker() reporting the work-budget steps spent and the cap, so a
-   self-test can prove the budget bounds a hostile pattern's work. */
-const char *strjoker_steps(const char *chaine, const char *joker,
-                           size_t *nsteps_out, size_t *maxsteps_out) {
-  size_t nsteps = 0;
-  const char *r = strjoker_bounded(chaine, joker, NULL, NULL, &nsteps);
+/* Test-only: strjoker() reporting the work and depth spent and their caps, so a
+   self-test can prove both bound a hostile pattern. */
+const char *strjoker_bounds(const char *chaine, const char *joker,
+                            size_t *nsteps_out, size_t *maxsteps_out,
+                            size_t *depth_out, size_t *maxdepth_out) {
+  size_t nsteps = 0, depth = 0;
+  const char *r = strjoker_bounded(chaine, joker, NULL, NULL, &nsteps, &depth);

  if (nsteps_out != NULL)
    *nsteps_out = nsteps;
  if (maxsteps_out != NULL)
    *maxsteps_out = STRJOKER_MAXSTEPS;
+  if (depth_out != NULL)
+    *depth_out = depth;
+  if (maxdepth_out != NULL)
+    *maxdepth_out = STRJOKER_MAXDEPTH;
  return r;
 }

-static const char *strjoker_impl(const strjoker_memo *memo, const char *chaine,
-                                 const char *joker, LLint *size,
-                                 int *size_flag) {
+static const char *strjoker_impl(strjoker_memo *memo, const char *chaine,
+                                 const char *joker, LLint *size, int *size_flag,
+                                 size_t depth) {
  if (strnotempty(joker) == 0) {        // fin de chaine joker
    if (strnotempty(chaine) == 0)       // fin aussi pour la chaine: ok
      return chaine;
@@ -403,7 +424,8 @@ static const char *strjoker_impl(const strjoker_memo *memo, const char *chaine,

      // tester sans le joker (pas ()+ mais ()*)
      if (!unique) {
-        if ((adr = strjoker_rec(memo, chaine, joker + jmp, size, size_flag))) {
+        if ((adr = strjoker_rec(memo, chaine, joker + jmp, size, size_flag,
+                                depth))) {
          return adr;
        }
      }
@@ -416,7 +438,7 @@ static const char *strjoker_impl(const strjoker_memo *memo, const char *chaine,
      while(i < (int) max) {
        if (pass[(int) (unsigned char) chaine[i]]) {    // caractère autorisé
          if ((adr = strjoker_rec(memo, chaine + i + 1, joker + jmp, size,
-                                  size_flag))) {
+                                  size_flag, depth))) {
            return adr;
          }
          i++;
@@ -427,7 +449,7 @@ static const char *strjoker_impl(const strjoker_memo *memo, const char *chaine,
      // tester chaîne vide
      if (i != max + 2)         // avant c'est ok
        if ((adr = strjoker_rec(memo, chaine + max, joker + jmp, size,
-                                size_flag)))
+                                size_flag, depth)))
          return adr;

      return NULL;              // perdu
@@ -449,7 +471,8 @@ static const char *strjoker_impl(const strjoker_memo *memo, const char *chaine,
      // comparaison ok?
      if (ok) {
        // continuer la comparaison.
-        if (strjoker_rec(memo, chaine + jmp, joker + jmp, size, size_flag))
+        if (strjoker_rec(memo, chaine + jmp, joker + jmp, size, size_flag,
+                         depth))
          return chaine;        // retourner 1e lettre
      }

@@ -471,8 +494,8 @@ const char *strjokerfind(const char *chaine, const char *joker) {
  if (chaine != NULL && strlen(chaine) > STRJOKER_MAXLEN)
    return NULL;
  while(*chaine) {
-    if ((adr = strjoker_bounded(chaine, joker, NULL, NULL,
-                                &nsteps))) { // ok trouvé
+    if ((adr = strjoker_bounded(chaine, joker, NULL, NULL, &nsteps,
+                                NULL))) { // ok trouvé
      return adr;
    }
    if (nsteps > STRJOKER_MAXSTEPS) // scan budget spent: no match
--- a/src/htsfilters.h
+++ b/src/htsfilters.h
@@ -52,10 +52,12 @@ HTS_INLINE const char *strjoker(const char *chaine, const char *joker, LLint * s
   oracle for the memoized matcher. */
 const char *strjoker_nomemo(const char *chaine, const char *joker, LLint *size,
                            int *size_flag);
-/* strjoker() reporting the work-budget steps it spent and the cap; test-only,
-   lets a self-test assert the budget bounds a hostile pattern's work. */
-const char *strjoker_steps(const char *chaine, const char *joker,
-                           size_t *nsteps_out, size_t *maxsteps_out);
+/* strjoker() reporting the work-budget steps and the recursion depth it spent,
+   with their caps; test-only, lets a self-test assert both bound a hostile
+   pattern (depth bounds the stack: an uncapped one overflows Windows' 1MB). */
+const char *strjoker_bounds(const char *chaine, const char *joker,
+                            size_t *nsteps_out, size_t *maxsteps_out,
+                            size_t *depth_out, size_t *maxdepth_out);
 const char *strjokerfind(const char *chaine, const char *joker);
 #endif

--- a/src/htsglobal.h
+++ b/src/htsglobal.h
@@ -322,16 +322,15 @@ typedef int64_t TStamp;
 /* Full printf conversion, '%' included (PRId64 has none): "X: " LLintP. */
 #define LLintP "%" PRId64

-/* Integer type for file offsets/sizes passed to the C library. Widens to
-   LLint (with HTS_FSEEKO for fseeko/ftello) under large-file support, plain
-   int otherwise; INTsysP is its printf conversion. */
-#ifdef LFS_FLAG
+/* Integer type for file offsets/sizes passed to the C library; INTsysP is its
+   printf conversion. FIXME: LFS_FLAG is a configure make variable, never a C
+   macro, so this test is dead and INTsys stays int on POSIX despite large-file
+   support (the real macro is HTS_LFS). Widening it there is an installed-header
+   type change, so it is left alone here. */
+#if defined(LFS_FLAG) || defined(_MSC_VER)
 typedef LLint INTsys;

 #define INTsysP LLintP
-#ifdef __linux
-#define HTS_FSEEKO
-#endif
 #else
 typedef int INTsys;

--- a/src/htshelp.c
+++ b/src/htshelp.c
@@ -477,7 +477,7 @@ void help(const char *app, int more) {
    ("  Y   mirror ALL links located in the first level pages (mirror links)");
  infomsg("");
  infomsg("Proxy options:");
-  infomsg("  P  proxy use (-P proxy:port or -P user:pass@proxy:port)");
+  infomsg("  P  proxy use (-P [socks5://][user:pass@]proxy:port)");
  infomsg(" %f *use proxy for ftp (f0 don't use)");
  infomsg(" %b  use this local hostname to make/send requests (-%b hostname)");
  infomsg("");
--- a/src/htsindex.c
+++ b/src/htsindex.c
@@ -318,7 +318,7 @@ void index_finish(const char *indexpath, int mode) {
  char catbuff[CATBUFF_SIZE];
  char **tab;
  char *blk;
-  off_t size = fpsize(fp_tmpproject);
+  LLint size = fpsize(fp_tmpproject);

  if (size > 0) {
    if (fp_tmpproject) {
--- a/src/htslib.c
+++ b/src/htslib.c
@@ -649,165 +649,6 @@ T_SOC http_fopen(httrackp * opt, const char *adr, const char *fil, htsblk * reto
  return http_xfopen(opt, 0, 1, 1, NULL, adr, fil, retour);
 }

-// Read a CRLF line from a non-blocking socket (waits up to timeout per recv).
-// Returns the line length (0 = empty), or -1 on timeout/EOF/error.
-static int proxy_getline(T_SOC soc, char *s, int max, int timeout) {
-  int j = 0;
-
-  for (;;) {
-    unsigned char ch;
-    int n;
-
-    if (!check_readinput_t(soc, timeout))
-      return -1; // timed out waiting for data
-    n = (int) recv(soc, &ch, 1, 0);
-    if (n == 1) {
-      if (ch == 13) // CR
-        continue;
-      if (ch == 10) // LF: end of line
-        break;
-      if (j >= max - 1)
-        return -1; // line too long: bound the read against a hostile proxy
-      s[j++] = (char) ch;
-    } else if (n == 0) {
-      return -1; // connection closed
-    } else {
-#ifdef _WIN32
-      if (WSAGetLastError() == WSAEWOULDBLOCK)
-        continue;
-#else
-      if (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK)
-        continue;
-#endif
-      return -1;
-    }
-  }
-  s[j] = '\0';
-  return j;
-}
-
-int http_proxy_tunnel(httrackp *opt, htsblk *retour, const char *adr,
-                      int timeout) {
-  const T_SOC soc = retour->soc;
-  const char *const host = jump_identification_const(adr); // host[:port]
-  const char *const portsep = jump_toport_const(adr);      // ":port" or NULL
-  char BIGSTK authority[HTS_URLMAXSIZE * 2];
-  char BIGSTK req[HTS_URLMAXSIZE * 4 + 1100];
-  char line[1024];
-  int code;
-
-  if (soc == INVALID_SOCKET)
-    return 0;
-
-  // CONNECT needs an explicit host:port; default the https port
-  authority[0] = '\0';
-  if (portsep != NULL)
-    strlcatbuff(authority, host, sizeof(authority)); // already host:port
-  else
-    snprintf(authority, sizeof(authority), "%s:%d", host, 443);
-
-  // backstop: never let a stray CR/LF in the host smuggle a second line into
-  // the CONNECT request (the host is already sanitized upstream)
-  {
-    const char *c;
-
-    for (c = authority; *c != '\0'; c++) {
-      if ((unsigned char) *c < ' ') {
-        strcpybuff(retour->msg, "proxy CONNECT: invalid host");
-        return 0;
-      }
-    }
-  }
-
-  snprintf(req, sizeof(req), "CONNECT %s HTTP/1.0" H_CRLF "Host: %s" H_CRLF,
-           authority, authority);
-
-  // creds go on the CONNECT, not the tunneled origin request
-  if (link_has_authorization(retour->req.proxy.name)) {
-    const char *a = jump_identification_const(retour->req.proxy.name);
-    const char *astart = jump_protocol_const(retour->req.proxy.name);
-    char autorisation[1100];
-    char user_pass[256];
-
-    autorisation[0] = user_pass[0] = '\0';
-    strncatbuff(user_pass, astart, (int) (a - astart) - 1);
-    strcpybuff(user_pass, unescape_http(OPT_GET_BUFF(opt),
-                                        OPT_GET_BUFF_SIZE(opt), user_pass));
-    code64((unsigned char *) user_pass, (int) strlen(user_pass),
-           (unsigned char *) autorisation, 0);
-    strlcatbuff(req, "Proxy-Authorization: Basic ", sizeof(req));
-    strlcatbuff(req, autorisation, sizeof(req));
-    strlcatbuff(req, H_CRLF, sizeof(req));
-  }
-  strlcatbuff(req, H_CRLF, sizeof(req)); // end of request headers
-
-  // raw send: ssl is set, so sendc() would route to TLS
-  {
-    const char *p = req;
-    size_t remain = strlen(req);
-    int stalls = 0;
-
-    while (remain > 0) {
-      const int n = (int) send(soc, p, (int) remain, 0);
-
-      if (n > 0) {
-        p += n;
-        remain -= (size_t) n;
-        stalls = 0;
-      } else {
-#ifdef _WIN32
-        const int wouldblock = (WSAGetLastError() == WSAEWOULDBLOCK);
-#else
-        const int wouldblock =
-            (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR);
-#endif
-        // don't spin forever on a fatal error or an unwritable socket
-        if (!wouldblock || !check_writeinput_t(soc, timeout) ||
-            ++stalls > 100) {
-          strcpybuff(retour->msg, "proxy CONNECT: write error");
-          return 0;
-        }
-      }
-    }
-  }
-
-  // proxy status line: "HTTP/1.x <code> ..."
-  if (proxy_getline(soc, line, sizeof(line), timeout) < 0) {
-    strcpybuff(retour->msg, "proxy CONNECT: no response");
-    return 0;
-  }
-  if (sscanf(line, "HTTP/%*d.%*d %d", &code) < 1)
-    code = 0;
-  if (code < 200 || code >= 300) {
-    snprintf(retour->msg, sizeof(retour->msg), "proxy CONNECT refused: %s",
-             strnotempty(line) ? line : "(no status)");
-    return 0;
-  }
-
-  // drain headers to the blank line; cap the count so a flooding proxy can't
-  // stall the crawl
-  {
-    int headers = 0;
-
-    for (;;) {
-      const int n = proxy_getline(soc, line, sizeof(line), timeout);
-
-      if (n < 0) {
-        strcpybuff(retour->msg, "proxy CONNECT: truncated response");
-        return 0;
-      }
-      if (n == 0)
-        break; // blank line: tunnel ready
-      if (++headers > 64) {
-        strcpybuff(retour->msg, "proxy CONNECT: too many response headers");
-        return 0;
-      }
-    }
-  }
-
-  return 1;
-}
-
 // ouverture d'une liaison http, envoi d'une requète
 // mode: 0 GET  1 HEAD  [2 POST]
 // treat: traiter header?
@@ -1106,8 +947,9 @@ int http_sendhead(httrackp * opt, t_cookie * cookie, int mode,
          /* widths bound method[256], url[HTS_URLMAXSIZE*2], protocol[256] */
          if (sscanf(line, "%255s %2047s %255s", method, url, protocol) == 3) {
            size_t ret;
-            // selon que l'on a ou pas un proxy
-            if (retour->req.proxy.active) {
+            // absolute-URI for an http proxy; a socks tunnel takes origin-form
+            if (retour->req.proxy.active &&
+                !hts_proxy_is_socks(retour->req.proxy.name)) {
              print_buffer(&bstr,
                      "%s http://%s%s %s\r\n", method, adr, url,
                      protocol);
@@ -1143,8 +985,10 @@ int http_sendhead(httrackp * opt, t_cookie * cookie, int mode,
        print_buffer(&bstr, "HEAD ");
    }

-    // si on gère un proxy, il faut une Absolute URI: on ajoute avant http://www.adr.dom
-    if (retour->req.proxy.active && (strncmp(adr, "https://", 8) != 0)) {
+    // an http proxy needs an absolute URI; a socks tunnel does not
+    if (retour->req.proxy.active &&
+        !hts_proxy_is_socks(retour->req.proxy.name) &&
+        (strncmp(adr, "https://", 8) != 0)) {
      if (!link_has_authority(adr)) {   // default http
 #if HDEBUG
        printf("Proxy Use: for %s%s proxy %d port %d\n", adr, fil,
@@ -1188,8 +1032,11 @@ int http_sendhead(httrackp * opt, t_cookie * cookie, int mode,
    if (xsend)
      print_buffer(&bstr, "%s", xsend);  // éventuelles autres lignes

-    // for https, auth rides the CONNECT (the tunneled GET would leak it)
-    if (retour->req.proxy.active && strncmp(adr, "https://", 8) != 0) {
+    // for https, auth rides the CONNECT (the tunneled GET would leak it); for
+    // socks, the handshake
+    if (retour->req.proxy.active &&
+        !hts_proxy_is_socks(retour->req.proxy.name) &&
+        strncmp(adr, "https://", 8) != 0) {
      if (link_has_authorization(retour->req.proxy.name)) {     // et hop, authentification proxy!
        const char *a = jump_identification_const(retour->req.proxy.name);
        const char *astart = jump_protocol_const(retour->req.proxy.name);
@@ -3878,11 +3725,16 @@ const char *jump_protocol_const(const char *source) {

 DECLARE_NON_CONST_VERSION(jump_protocol)

+hts_boolean hts_proxy_is_socks(const char *name) {
+  if (name == NULL)
+    return HTS_FALSE;
+  return (strfield(name, "socks5h:") || strfield(name, "socks5:")) ? HTS_TRUE
+                                                                   : HTS_FALSE;
+}
+
 // default proxy port for a -P argument, keyed on the scheme
 static int proxy_default_port(const char *arg) {
-  if (strfield(arg, "socks5h:") || strfield(arg, "socks5:"))
-    return 1080;
-  return 8080;
+  return hts_proxy_is_socks(arg) ? 1080 : 8080;
 }

 void hts_parse_proxy(const char *arg, char *name, size_t name_size, int *port) {
@@ -4739,26 +4591,31 @@ int fexist_utf8(const char *s) {
  return 0;
 }

-/* Taille d'un fichier, -1 si n'existe pas */
+/* File size, -1 if absent */
 /* Note: NOT utf-8 */
-off_t fsize(const char *s) {
-  struct stat st;
+LLint fsize(const char *s) {
+  STRUCT_STAT st;

-  if (!strnotempty(s))          // nom vide: erreur
+  if (!strnotempty(s)) // empty name: error
    return -1;
+  /* _stat64, not stat(): the latter is 32-bit on MSVC */
+#ifdef _WIN32
+  if (_stat64(s, &st) == 0 && S_ISREG(st.st_mode)) {
+#else
  if (stat(s, &st) == 0 && S_ISREG(st.st_mode)) {
+#endif
    return st.st_size;
  } else {
    return -1;
  }
 }

-/* Taille d'un fichier, -1 si n'existe pas */
+/* File size, -1 if absent */
 /* Note: utf-8 */
-off_t fsize_utf8(const char *s) {
+LLint fsize_utf8(const char *s) {
  STRUCT_STAT st;

-  if (!strnotempty(s))          // nom vide: erreur
+  if (!strnotempty(s)) // empty name: error
    return -1;
  if (STAT(s, &st) == 0 && S_ISREG(st.st_mode)) {
    return st.st_size;
@@ -4767,24 +4624,17 @@ off_t fsize_utf8(const char *s) {
  }
 }

-off_t fpsize(FILE * fp) {
-  off_t oldpos, size;
+/* fseeko/ftello, never fseek/ftell: ftell returns long, which cannot carry an
+   offset past 2GB on a 32-bit platform and fails with EOVERFLOW there. */
+LLint fpsize(FILE *fp) {
+  LLint oldpos, size;

  if (!fp)
    return -1;
-#ifdef HTS_FSEEKO
  oldpos = ftello(fp);
-#else
-  oldpos = ftell(fp);
-#endif
-  fseek(fp, 0, SEEK_END);
-#ifdef HTS_FSEEKO
+  fseeko(fp, 0, SEEK_END);
  size = ftello(fp);
  fseeko(fp, oldpos, SEEK_SET);
-#else
-  size = ftell(fp);
-  fseek(fp, oldpos, SEEK_SET);
-#endif
  return size;
 }

@@ -6548,13 +6398,13 @@ int hts_stat_utf8(const char *path, STRUCT_STAT * buf) {
  LPWSTR wpath = hts_convertUTF8StringToUCS2(path, (int) strlen(path), NULL);

  if (wpath != NULL) {
-    const int result = _wstat(wpath, buf);
+    const int result = _wstat64(wpath, buf);

    free(wpath);
    return result;
  } else {
    // Fallback on conversion error.
-    return _stat(path, buf);
+    return _stat64(path, buf);
  }
 }

--- a/src/htslib.h
+++ b/src/htslib.h
@@ -207,15 +207,9 @@ int check_readinput(htsblk * r);
 int check_readinput_t(T_SOC soc, int timeout);
 int check_writeinput_t(T_SOC soc, int timeout);

-/* Open an HTTP CONNECT tunnel through the active proxy for an https request:
-   `retour->soc` must already be TCP-connected to the proxy, and `adr` is the
-   origin authority (url_adr, e.g. "https://host:port"). Sends the CONNECT
-   request (with Proxy-Authorization when the proxy carries credentials) and
-   reads the proxy's status line, so the caller's TLS handshake then runs
-   end-to-end with the origin. Blocks up to `timeout` seconds. Returns 1 on a
-   2xx tunnel, 0 on failure (retour->msg/statuscode set). */
-int http_proxy_tunnel(httrackp *opt, htsblk *retour, const char *adr,
-                      int timeout);
+/* TRUE if this -P proxy name (which keeps its scheme) is a SOCKS5 proxy. */
+hts_boolean hts_proxy_is_socks(const char *name);
+
 void treathead(t_cookie * cookie, const char *adr, const char *fil, htsblk * retour,
               char *rcvd);
 void treatfirstline(htsblk * retour, const char *rcvd);
@@ -316,10 +310,11 @@ void cut_path(char *fullpath, char *path, size_t path_size, char *pname,
 int fexist(const char *s);
 int fexist_utf8(const char *s);

-/*LLint fsize(const char* s);    */
-off_t fpsize(FILE * fp);
-off_t fsize(const char *s);
-off_t fsize_utf8(const char *s);
+/* File size in bytes, -1 if absent or not a regular file. LLint, not off_t:
+   the latter is a 32-bit long on MSVC, truncating any file of 2GB or more. */
+LLint fpsize(FILE *fp);
+LLint fsize(const char *s);
+LLint fsize_utf8(const char *s);

 // Threads
 typedef void *(*beginthread_type) (void *);
@@ -399,7 +394,8 @@ void *hts_get_callback(t_hts_htmlcheck_callbacks * callbacks,
     HTSEXT_API FILE *hts_fopen_utf8(const char *path, const char *mode);

 #define STAT hts_stat_utf8
-     typedef struct _stat STRUCT_STAT;
+     /* _stat64: _stat's st_size is a 32-bit long, even in x64 builds */
+     typedef struct _stat64 STRUCT_STAT;
     HTSEXT_API int hts_stat_utf8(const char *path, STRUCT_STAT * buf);

 #define UNLINK hts_unlink_utf8
@@ -597,9 +593,9 @@ HTS_STATIC int compare_mime(httrackp * opt, const char *mime, const char *file,
 #endif

 // returns (size_t) -1 upon error
-static HTS_UNUSED size_t off_t_to_size_t(off_t o) {
+static HTS_UNUSED size_t llint_to_size_t(LLint o) {
  const size_t so = (size_t) o;
-  if ((off_t) so == o) {
+  if ((LLint) so == o) {
    return so;
  } else {
    return (size_t) -1;
--- a/src/htsproxy.c
+++ b/src/htsproxy.c
@@ -0,0 +1,539 @@
+/* ------------------------------------------------------------ */
+/*
+HTTrack Website Copier, Offline Browser for Windows and Unix
+Copyright (C) 2026 Xavier Roche and other contributors
+
+SPDX-License-Identifier: GPL-3.0-or-later
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+Ethical use: we kindly ask that you NOT use this software to harvest email
+addresses or to collect any other private information about people. Doing so
+would dishonor our work and waste the many hours we have spent on it.
+
+Please visit our Website: http://www.httrack.com
+*/
+
+/* ------------------------------------------------------------ */
+/* File: Proxy tunneling (HTTP CONNECT, SOCKS5)                 */
+/* Author: Xavier Roche                                         */
+/* ------------------------------------------------------------ */
+
+/* Internal engine bytecode */
+#define HTS_INTERNAL_BYTECODE
+
+#include "htscore.h"
+
+#include "htslib.h"
+#include "htsproxy.h"
+
+#include <string.h>
+
+// Read a CRLF line from a non-blocking socket (waits up to timeout per recv).
+// Returns the line length (0 = empty), or -1 on timeout/EOF/error.
+static int proxy_getline(T_SOC soc, char *s, int max, int timeout) {
+  int j = 0;
+
+  for (;;) {
+    unsigned char ch;
+    int n;
+
+    if (!check_readinput_t(soc, timeout))
+      return -1; // timed out waiting for data
+    n = (int) recv(soc, &ch, 1, 0);
+    if (n == 1) {
+      if (ch == 13) // CR
+        continue;
+      if (ch == 10) // LF: end of line
+        break;
+      if (j >= max - 1)
+        return -1; // line too long: bound the read against a hostile proxy
+      s[j++] = (char) ch;
+    } else if (n == 0) {
+      return -1; // connection closed
+    } else {
+#ifdef _WIN32
+      if (WSAGetLastError() == WSAEWOULDBLOCK)
+        continue;
+#else
+      if (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK)
+        continue;
+#endif
+      return -1;
+    }
+  }
+  s[j] = '\0';
+  return j;
+}
+
+int http_proxy_tunnel(httrackp *opt, htsblk *retour, const char *adr,
+                      int timeout) {
+  const T_SOC soc = retour->soc;
+  const char *const host = jump_identification_const(adr); // host[:port]
+  const char *const portsep = jump_toport_const(adr);      // ":port" or NULL
+  char BIGSTK authority[HTS_URLMAXSIZE * 2];
+  char BIGSTK req[HTS_URLMAXSIZE * 4 + 1100];
+  char line[1024];
+  int code;
+
+  if (soc == INVALID_SOCKET)
+    return 0;
+
+  // CONNECT needs an explicit host:port; default the https port
+  authority[0] = '\0';
+  if (portsep != NULL)
+    strlcatbuff(authority, host, sizeof(authority)); // already host:port
+  else
+    snprintf(authority, sizeof(authority), "%s:%d", host, 443);
+
+  // backstop: never let a stray CR/LF in the host smuggle a second line into
+  // the CONNECT request (the host is already sanitized upstream)
+  {
+    const char *c;
+
+    for (c = authority; *c != '\0'; c++) {
+      if ((unsigned char) *c < ' ') {
+        strcpybuff(retour->msg, "proxy CONNECT: invalid host");
+        return 0;
+      }
+    }
+  }
+
+  snprintf(req, sizeof(req), "CONNECT %s HTTP/1.0" H_CRLF "Host: %s" H_CRLF,
+           authority, authority);
+
+  // creds go on the CONNECT, not the tunneled origin request
+  if (link_has_authorization(retour->req.proxy.name)) {
+    const char *a = jump_identification_const(retour->req.proxy.name);
+    const char *astart = jump_protocol_const(retour->req.proxy.name);
+    char autorisation[1100];
+    char user_pass[256];
+
+    autorisation[0] = user_pass[0] = '\0';
+    strncatbuff(user_pass, astart, (int) (a - astart) - 1);
+    strcpybuff(user_pass, unescape_http(OPT_GET_BUFF(opt),
+                                        OPT_GET_BUFF_SIZE(opt), user_pass));
+    code64((unsigned char *) user_pass, (int) strlen(user_pass),
+           (unsigned char *) autorisation, 0);
+    strlcatbuff(req, "Proxy-Authorization: Basic ", sizeof(req));
+    strlcatbuff(req, autorisation, sizeof(req));
+    strlcatbuff(req, H_CRLF, sizeof(req));
+  }
+  strlcatbuff(req, H_CRLF, sizeof(req)); // end of request headers
+
+  // raw send: ssl is set, so sendc() would route to TLS
+  {
+    const char *p = req;
+    size_t remain = strlen(req);
+    int stalls = 0;
+
+    while (remain > 0) {
+      const int n = (int) send(soc, p, (int) remain, 0);
+
+      if (n > 0) {
+        p += n;
+        remain -= (size_t) n;
+        stalls = 0;
+      } else {
+#ifdef _WIN32
+        const int wouldblock = (WSAGetLastError() == WSAEWOULDBLOCK);
+#else
+        const int wouldblock =
+            (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR);
+#endif
+        // don't spin forever on a fatal error or an unwritable socket
+        if (!wouldblock || !check_writeinput_t(soc, timeout) ||
+            ++stalls > 100) {
+          strcpybuff(retour->msg, "proxy CONNECT: write error");
+          return 0;
+        }
+      }
+    }
+  }
+
+  // proxy status line: "HTTP/1.x <code> ..."
+  if (proxy_getline(soc, line, sizeof(line), timeout) < 0) {
+    strcpybuff(retour->msg, "proxy CONNECT: no response");
+    return 0;
+  }
+  if (sscanf(line, "HTTP/%*d.%*d %d", &code) < 1)
+    code = 0;
+  if (code < 200 || code >= 300) {
+    snprintf(retour->msg, sizeof(retour->msg), "proxy CONNECT refused: %s",
+             strnotempty(line) ? line : "(no status)");
+    return 0;
+  }
+
+  // drain headers to the blank line; cap the count so a flooding proxy can't
+  // stall the crawl
+  {
+    int headers = 0;
+
+    for (;;) {
+      const int n = proxy_getline(soc, line, sizeof(line), timeout);
+
+      if (n < 0) {
+        strcpybuff(retour->msg, "proxy CONNECT: truncated response");
+        return 0;
+      }
+      if (n == 0)
+        break; // blank line: tunnel ready
+      if (++headers > 64) {
+        strcpybuff(retour->msg, "proxy CONNECT: too many response headers");
+        return 0;
+      }
+    }
+  }
+
+  return 1;
+}
+
+/* SOCKS5 client (RFC 1928, RFC 1929 auth), hostname mode only: the proxy
+   resolves the origin name (remote DNS, curl's socks5h). The stream is the
+   proxy socket, or a scripted buffer under -#test=socks5. */
+
+#define SOCKS5_VERSION 0x05
+#define SOCKS5_AUTH_VERSION 0x01
+#define SOCKS5_METHOD_NONE 0x00
+#define SOCKS5_METHOD_USERPASS 0x02
+#define SOCKS5_METHOD_NOACCEPTABLE 0xFF
+#define SOCKS5_CMD_CONNECT 0x01
+#define SOCKS5_ATYP_IPV4 0x01
+#define SOCKS5_ATYP_DOMAIN 0x03
+#define SOCKS5_ATYP_IPV6 0x04
+#define SOCKS5_MAXFIELD 255 /* one length byte: host, user and password */
+
+typedef struct socks5_stream {
+  T_SOC soc; /* INVALID_SOCKET when scripted (self-test) */
+  int timeout;
+  socks5_test_io *io;
+} socks5_stream;
+
+static int socks5_fail(char *msg, size_t msgsize, const char *text) {
+  if (msgsize != 0)
+    strlcpybuff(msg, text, msgsize);
+  return 0;
+}
+
+/* Read exactly n bytes, or fail: SOCKS frames are not self-delimiting, so a
+   short read would desync the stream shared with the origin traffic. */
+static int socks5_read_n(socks5_stream *st, unsigned char *buf, size_t n) {
+  size_t got = 0;
+  int stalls = 0;
+
+  if (st->soc == INVALID_SOCKET) { /* scripted */
+    socks5_test_io *const io = st->io;
+
+    if (n > io->reply_len - io->consumed)
+      return 0;
+    memcpy(buf, io->reply + io->consumed, n);
+    io->consumed += n;
+    return 1;
+  }
+  while (got < n) {
+    const int r = (int) recv(st->soc, (char *) buf + got, (int) (n - got), 0);
+
+    if (r > 0) {
+      got += (size_t) r;
+      stalls = 0;
+    } else if (r == 0) {
+      return 0; // proxy closed mid-frame
+    } else {
+#ifdef _WIN32
+      const int wouldblock = (WSAGetLastError() == WSAEWOULDBLOCK);
+#else
+      const int wouldblock =
+          (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR);
+#endif
+      if (!wouldblock || !check_readinput_t(st->soc, st->timeout) ||
+          ++stalls > 100)
+        return 0;
+    }
+  }
+  return 1;
+}
+
+static int socks5_write_all(socks5_stream *st, const unsigned char *buf,
+                            size_t len) {
+  size_t remain = len;
+  int stalls = 0;
+
+  if (st->soc == INVALID_SOCKET) { /* scripted */
+    socks5_test_io *const io = st->io;
+
+    if (len > sizeof(io->sent) - io->sent_len)
+      return 0;
+    memcpy(io->sent + io->sent_len, buf, len);
+    io->sent_len += len;
+    return 1;
+  }
+  while (remain > 0) {
+    // raw send: the socket is still plain here, sendc() would route to TLS
+    const int n = (int) send(st->soc, (const char *) buf, (int) remain, 0);
+
+    if (n > 0) {
+      buf += n;
+      remain -= (size_t) n;
+      stalls = 0;
+    } else {
+#ifdef _WIN32
+      const int wouldblock = (WSAGetLastError() == WSAEWOULDBLOCK);
+#else
+      const int wouldblock =
+          (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR);
+#endif
+      if (!wouldblock || !check_writeinput_t(st->soc, st->timeout) ||
+          ++stalls > 100)
+        return 0;
+    }
+  }
+  return 1;
+}
+
+static const char *socks5_rep_message(unsigned char rep) {
+  switch (rep) {
+  case 0x01:
+    return "general failure";
+  case 0x02:
+    return "connection not allowed by ruleset";
+  case 0x03:
+    return "network unreachable";
+  case 0x04:
+    return "host unreachable";
+  case 0x05:
+    return "connection refused";
+  case 0x06:
+    return "TTL expired";
+  case 0x07:
+    return "command not supported";
+  case 0x08:
+    return "address type not supported";
+  default:
+    return "unknown error";
+  }
+}
+
+/* The reply's BND.ADDR is variable-length: consume exactly what ATYP says, or
+   the leftover bytes prepend to the first origin (or TLS) read. */
+static int socks5_read_reply(socks5_stream *st, char *msg, size_t msgsize) {
+  unsigned char head[4];
+  unsigned char addr[SOCKS5_MAXFIELD + 2];
+  size_t addrlen;
+
+  if (!socks5_read_n(st, head, sizeof(head)))
+    return socks5_fail(msg, msgsize, "SOCKS5: no reply from proxy");
+  if (head[0] != SOCKS5_VERSION)
+    return socks5_fail(msg, msgsize, "SOCKS5: bad version in reply");
+  if (head[1] != 0x00) {
+    snprintf(msg, msgsize, "SOCKS5 connect failed: %s",
+             socks5_rep_message(head[1]));
+    return 0;
+  }
+  switch (head[3]) {
+  case SOCKS5_ATYP_IPV4:
+    addrlen = 4;
+    break;
+  case SOCKS5_ATYP_IPV6:
+    addrlen = 16;
+    break;
+  case SOCKS5_ATYP_DOMAIN: {
+    unsigned char len;
+
+    if (!socks5_read_n(st, &len, 1))
+      return socks5_fail(msg, msgsize, "SOCKS5: truncated reply");
+    addrlen = len; // <= 255, always fits addr[]
+    break;
+  }
+  default: // unknown length: the stream cannot be resynchronized
+    return socks5_fail(msg, msgsize, "SOCKS5: unknown address type in reply");
+  }
+  if (addrlen != 0 && !socks5_read_n(st, addr, addrlen))
+    return socks5_fail(msg, msgsize, "SOCKS5: truncated reply address");
+  if (!socks5_read_n(st, addr, 2)) // BND.PORT, unused
+    return socks5_fail(msg, msgsize, "SOCKS5: truncated reply port");
+  return 1;
+}
+
+static int socks5_negotiate(socks5_stream *st, const char *host, size_t hostlen,
+                            int port, const char *user, size_t userlen,
+                            const char *pass, size_t passlen, int want_auth,
+                            char *msg, size_t msgsize) {
+  unsigned char frame[3 + SOCKS5_MAXFIELD + SOCKS5_MAXFIELD];
+  unsigned char rep[2];
+
+  /* greeting */
+  frame[0] = SOCKS5_VERSION;
+  frame[1] = (unsigned char) (want_auth ? 2 : 1);
+  frame[2] = SOCKS5_METHOD_NONE;
+  frame[3] = SOCKS5_METHOD_USERPASS;
+  if (!socks5_write_all(st, frame, (size_t) 2 + frame[1]))
+    return socks5_fail(msg, msgsize, "SOCKS5: write error");
+  if (!socks5_read_n(st, rep, sizeof(rep)))
+    return socks5_fail(msg, msgsize, "SOCKS5: no method reply from proxy");
+  if (rep[0] != SOCKS5_VERSION)
+    return socks5_fail(msg, msgsize, "SOCKS5: bad version in method reply");
+  switch (rep[1]) {
+  case SOCKS5_METHOD_NONE:
+    break;
+  case SOCKS5_METHOD_USERPASS:
+    if (!want_auth)
+      return socks5_fail(msg, msgsize,
+                         "SOCKS5: proxy requires authentication, none given");
+    /* RFC 1929 sub-negotiation; its version byte is 0x01, not 0x05 */
+    frame[0] = SOCKS5_AUTH_VERSION;
+    frame[1] = (unsigned char) userlen;
+    memcpy(frame + 2, user, userlen);
+    frame[2 + userlen] = (unsigned char) passlen;
+    memcpy(frame + 3 + userlen, pass, passlen);
+    if (!socks5_write_all(st, frame, 3 + userlen + passlen))
+      return socks5_fail(msg, msgsize, "SOCKS5: write error");
+    if (!socks5_read_n(st, rep, sizeof(rep)))
+      return socks5_fail(msg, msgsize, "SOCKS5: no authentication reply");
+    if (rep[1] != 0x00)
+      return socks5_fail(msg, msgsize, "SOCKS5: authentication failed");
+    break;
+  case SOCKS5_METHOD_NOACCEPTABLE:
+    return socks5_fail(
+        msg, msgsize,
+        "SOCKS5: proxy accepts no authentication method we offer");
+  default:
+    return socks5_fail(msg, msgsize,
+                       "SOCKS5: proxy selected an unknown method");
+  }
+
+  /* CONNECT to the origin, by name */
+  frame[0] = SOCKS5_VERSION;
+  frame[1] = SOCKS5_CMD_CONNECT;
+  frame[2] = 0x00; // RSV
+  frame[3] = SOCKS5_ATYP_DOMAIN;
+  frame[4] = (unsigned char) hostlen;
+  memcpy(frame + 5, host, hostlen);
+  frame[5 + hostlen] = (unsigned char) (port >> 8);
+  frame[6 + hostlen] = (unsigned char) (port & 0xFF);
+  if (!socks5_write_all(st, frame, 7 + hostlen))
+    return socks5_fail(msg, msgsize, "SOCKS5: write error");
+
+  return socks5_read_reply(st, msg, msgsize);
+}
+
+/* Decode the proxy userinfo into the two RFC 1929 fields. Split on the first
+   colon of the still-escaped string, so a %3A stays inside the username. */
+static int socks5_credentials(httrackp *opt, const char *proxy_name, char *user,
+                              size_t user_size, size_t *userlen, char *pass,
+                              size_t pass_size, size_t *passlen, char *msg,
+                              size_t msgsize) {
+  const char *const a = jump_identification_const(proxy_name); // past the '@'
+  const char *const astart = jump_protocol_const(proxy_name);
+  char userinfo[1024];
+  char *colon;
+
+  if (a <= astart || (size_t) (a - astart) - 1 >= sizeof(userinfo))
+    return socks5_fail(msg, msgsize, "SOCKS5: credentials too long");
+  userinfo[0] = '\0';
+  strncatbuff(userinfo, astart, (int) (a - astart) - 1);
+  colon = strchr(userinfo, ':');
+  if (colon != NULL)
+    *colon++ = '\0';
+  strlcpybuff(
+      user, unescape_http(OPT_GET_BUFF(opt), OPT_GET_BUFF_SIZE(opt), userinfo),
+      user_size);
+  strlcpybuff(pass,
+              colon != NULL ? unescape_http(OPT_GET_BUFF(opt),
+                                            OPT_GET_BUFF_SIZE(opt), colon)
+                            : "",
+              pass_size);
+  *userlen = strlen(user);
+  *passlen = strlen(pass);
+  // reject, never truncate: a clipped secret would authenticate as another one
+  if (*userlen > SOCKS5_MAXFIELD || *passlen > SOCKS5_MAXFIELD)
+    return socks5_fail(msg, msgsize, "SOCKS5: credentials too long");
+  if (*userlen == 0)
+    return socks5_fail(msg, msgsize, "SOCKS5: empty proxy username");
+  return 1;
+}
+
+static int socks5_handshake_stream(httrackp *opt, socks5_stream *st,
+                                   const char *adr, const char *proxy_name,
+                                   int ssl, char *msg, size_t msgsize) {
+  const char *const host = jump_identification_const(adr);
+  const char *const portsep = jump_toport_const(adr);
+  const size_t hostlen =
+      portsep != NULL ? (size_t) (portsep - host) : strlen(host);
+  // sized for the whole userinfo: decoding shrinks, so an over-long credential
+  // lands intact and is rejected below rather than silently clipped
+  char user[1024];
+  char pass[1024];
+  size_t userlen = 0, passlen = 0;
+  int want_auth = 0;
+  int port = ssl ? 443 : 80;
+  size_t i;
+
+  if (hostlen == 0 || hostlen > SOCKS5_MAXFIELD)
+    return socks5_fail(msg, msgsize, "SOCKS5: invalid origin host");
+  if (host[0] == '[') // ATYP=domain cannot carry an IPv6 literal
+    return socks5_fail(msg, msgsize,
+                       "SOCKS5: IPv6 literal origin is not supported");
+  for (i = 0; i < hostlen; i++) {
+    if ((unsigned char) host[i] < ' ')
+      return socks5_fail(msg, msgsize, "SOCKS5: invalid origin host");
+  }
+  if (portsep != NULL) {
+    int p = -1;
+
+    sscanf(portsep + 1, "%d", &p);
+    if (p <= 0 || p > 65535)
+      return socks5_fail(msg, msgsize, "SOCKS5: invalid origin port");
+    port = p;
+  }
+  if (link_has_authorization(proxy_name)) {
+    if (!socks5_credentials(opt, proxy_name, user, sizeof(user), &userlen, pass,
+                            sizeof(pass), &passlen, msg, msgsize))
+      return 0;
+    want_auth = 1;
+  }
+  return socks5_negotiate(st, host, hostlen, port, user, userlen, pass, passlen,
+                          want_auth, msg, msgsize);
+}
+
+int socks5_handshake(httrackp *opt, htsblk *retour, const char *adr,
+                     int timeout) {
+  socks5_stream st;
+#if HTS_USEOPENSSL
+  const int ssl = retour->ssl;
+#else
+  const int ssl = 0;
+#endif
+
+  if (retour->soc == INVALID_SOCKET)
+    return 0;
+  st.soc = retour->soc;
+  st.timeout = timeout;
+  st.io = NULL;
+  return socks5_handshake_stream(opt, &st, adr, retour->req.proxy.name, ssl,
+                                 retour->msg, sizeof(retour->msg));
+}
+
+int socks5_handshake_scripted(httrackp *opt, const char *adr,
+                              const char *proxy_name, socks5_test_io *io) {
+  socks5_stream st;
+
+  st.soc = INVALID_SOCKET;
+  st.timeout = 0;
+  st.io = io;
+  io->consumed = 0;
+  io->sent_len = 0;
+  io->msg[0] = '\0';
+  return socks5_handshake_stream(opt, &st, adr, proxy_name, 0, io->msg,
+                                 sizeof(io->msg));
+}
--- a/src/htsproxy.h
+++ b/src/htsproxy.h
@@ -0,0 +1,82 @@
+/* ------------------------------------------------------------ */
+/*
+HTTrack Website Copier, Offline Browser for Windows and Unix
+Copyright (C) 2026 Xavier Roche and other contributors
+
+SPDX-License-Identifier: GPL-3.0-or-later
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+Ethical use: we kindly ask that you NOT use this software to harvest email
+addresses or to collect any other private information about people. Doing so
+would dishonor our work and waste the many hours we have spent on it.
+
+Please visit our Website: http://www.httrack.com
+*/
+
+/* ------------------------------------------------------------ */
+/* File: Proxy tunneling (HTTP CONNECT, SOCKS5) .h              */
+/* Author: Xavier Roche                                         */
+/* ------------------------------------------------------------ */
+
+#ifndef HTS_DEFPROXY
+#define HTS_DEFPROXY
+
+#include "htsglobal.h"
+
+/* Forward definitions */
+#ifndef HTS_DEF_FWSTRUCT_httrackp
+#define HTS_DEF_FWSTRUCT_httrackp
+typedef struct httrackp httrackp;
+#endif
+#ifndef HTS_DEF_FWSTRUCT_htsblk
+#define HTS_DEF_FWSTRUCT_htsblk
+typedef struct htsblk htsblk;
+#endif
+
+/* Open an HTTP CONNECT tunnel through the active proxy for an https request:
+   `retour->soc` must already be TCP-connected to the proxy, and `adr` is the
+   origin authority (url_adr, e.g. "https://host:port"). Sends the CONNECT
+   request (with Proxy-Authorization when the proxy carries credentials) and
+   reads the proxy's status line, so the caller's TLS handshake then runs
+   end-to-end with the origin. Blocks up to `timeout` seconds. Returns 1 on a
+   2xx tunnel, 0 on failure (retour->msg/statuscode set). */
+int http_proxy_tunnel(httrackp *opt, htsblk *retour, const char *adr,
+                      int timeout);
+
+/* SOCKS5 (RFC 1928, RFC 1929 auth) handshake on the raw proxy socket, before
+   any TLS: `retour->soc` must be TCP-connected to the proxy and `adr` is the
+   origin (url_adr). The origin name is sent verbatim (ATYP=domain), so the
+   proxy resolves it; a bracketed IPv6 literal origin is rejected. Blocks up to
+   `timeout` seconds. Returns 1 with the stream positioned on the first origin
+   byte, 0 on failure (retour->msg set). */
+int socks5_handshake(httrackp *opt, htsblk *retour, const char *adr,
+                     int timeout);
+
+/* Self-test hook (-#test=socks5): run the handshake against `reply`, a scripted
+   server byte stream, instead of a socket. `sent` captures the client frames,
+   `consumed` the reply bytes eaten (the frame-desync guard). */
+typedef struct socks5_test_io {
+  const unsigned char *reply;
+  size_t reply_len;
+  size_t consumed;
+  unsigned char sent[1024];
+  size_t sent_len;
+  char msg[256];
+} socks5_test_io;
+
+int socks5_handshake_scripted(httrackp *opt, const char *adr,
+                              const char *proxy_name, socks5_test_io *io);
+
+#endif
--- a/src/htsselftest.c
+++ b/src/htsselftest.c
@@ -55,6 +55,7 @@ Please visit our Website: http://www.httrack.com
 #include "htsmd5.h"
 #include "htssniff.h"
 #include "htscodec.h"
+#include "htsproxy.h"
 #if HTS_USEZLIB
 #include "htszlib.h"
 #endif
@@ -64,6 +65,7 @@ Please visit our Website: http://www.httrack.com
 #include "coucal/coucal.h"

 #include <ctype.h>
+#include <errno.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -71,6 +73,9 @@ Please visit our Website: http://www.httrack.com
 #ifndef _WIN32
 #include <sys/socket.h>
 #include <unistd.h>
+#else
+#include <io.h>       /* _get_osfhandle, for the sparse-file hint */
+#include <winioctl.h> /* FSCTL_SET_SPARSE */
 #endif

 /* very minimalistic internal tests */
@@ -752,7 +757,7 @@ static int st_filterbounds(httrackp *opt, int argc, char **argv) {
  const size_t subjlen = 2048;
  char *subj = malloct(big + 1);
  char *pat = malloct(2 * stars + 2);
-  size_t steps = 0, maxsteps = 0, i;
+  size_t steps = 0, maxsteps = 0, depth = 0, maxdepth = 0, i;

  (void) opt;
  (void) argc;
@@ -773,9 +778,22 @@ static int st_filterbounds(httrackp *opt, int argc, char **argv) {
  subj[subjlen] = '\0';
  /* Budget must fire and hold: steps > cap (deleting the budget zeroes the
     counter that is the enforcement), steps < 10*cap (unbudgeted ~1.26e9). */
-  assertf(strjoker_steps(subj, pat, &steps, &maxsteps) == NULL);
+  assertf(strjoker_bounds(subj, pat, &steps, &maxsteps, &depth, &maxdepth) ==
+          NULL);
  assertf(steps > maxsteps && steps < 10 * maxsteps);
+  /* Depth caps the stack: uncapped this recurses 2046 frames, ~900KB (#574). */
+  assertf(depth == maxdepth);
  assertf(strjokerfind(subj, pat) == NULL);
+  /* Pin the cap from below: 32 segments must still match, so a cap set so low
+     it would break real multi-segment filters (which use far fewer) fails. */
+  for (i = 0; i < 32; i++) {
+    pat[2 * i] = '*';
+    pat[2 * i + 1] = 'a';
+  }
+  pat[64] = '\0';
+  memset(subj, 'a', 32);
+  subj[32] = '\0';
+  assertf(strjoker(subj, pat, NULL, NULL) != NULL);
  freet(pat);
  freet(subj);
  printf("filterbounds: OK\n");
@@ -812,7 +830,11 @@ static int st_mime(httrackp *opt, int argc, char **argv) {
  return 0;
 }

+static size_t st_decode_body(const char *arg, char *buf, size_t size);
+
 static int st_charset(httrackp *opt, int argc, char **argv) {
+  char buf[512];
+  size_t len;
  char *s;

  (void) opt;
@@ -820,7 +842,8 @@ static int st_charset(httrackp *opt, int argc, char **argv) {
    fprintf(stderr, "charset: needs a charset and a string\n");
    return 1;
  }
-  s = hts_convertStringToUTF8(argv[1], strlen(argv[1]), argv[0]);
+  len = st_decode_body(argv[1], buf, sizeof(buf));
+  s = hts_convertStringToUTF8(buf, len, argv[0]);
  if (s != NULL) {
    printf("%s\n", s);
    freet(s);
@@ -845,16 +868,22 @@ static int st_metacharset(httrackp *opt, int argc, char **argv) {
 }

 static int st_isutf8(httrackp *opt, int argc, char **argv) {
+  char buf[512];
+  size_t len;
+
  (void) opt;
  if (argc < 1) {
    fprintf(stderr, "isutf8: needs a string\n");
    return 1;
  }
-  printf("%d\n", hts_isStringUTF8(argv[0], strlen(argv[0])) ? 1 : 0);
+  len = st_decode_body(argv[0], buf, sizeof(buf));
+  printf("%d\n", hts_isStringUTF8(buf, len) ? 1 : 0);
  return 0;
 }

 static int st_idna_encode(httrackp *opt, int argc, char **argv) {
+  char buf[512];
+  size_t len;
  char *s;

  (void) opt;
@@ -862,7 +891,8 @@ static int st_idna_encode(httrackp *opt, int argc, char **argv) {
    fprintf(stderr, "idna-encode: needs a hostname\n");
    return 1;
  }
-  s = hts_convertStringUTF8ToIDNA(argv[0], strlen(argv[0]));
+  len = st_decode_body(argv[0], buf, sizeof(buf));
+  s = hts_convertStringUTF8ToIDNA(buf, len);
  if (s != NULL) {
    printf("%s\n", s);
    freet(s);
@@ -1024,7 +1054,7 @@ static int st_hashtable(httrackp *opt, int argc, char **argv) {

  /* produce random patterns, or read from a file */
  if (sscanf(snum, "%lu", &count) != 1) {
-    const off_t size = fsize(snum);
+    const LLint size = fsize(snum);
    FILE *fp = fopen(snum, "rb");
    if (fp != NULL) {
      buff = malloct(size);
@@ -1124,7 +1154,10 @@ static int st_strsafe(httrackp *opt, int argc, char **argv) {
       comes from argv so its length is opaque to the compiler (no static
       -Wstringop-overflow, genuine runtime check). "overflow-buff" exercises
       htsbuff. */
-    char small[4];
+    /* Not sizeof(char*): on ILP32 a char[4] equals the pointer size, and the
+       MSVC array-vs-pointer heuristic (sizeof(A) != sizeof(char*)) then reads
+       it as a pointer and silently skips the bound. */
+    char small[6];
    const char *const src = (argc >= 2) ? argv[1] : "overflowing";

    if (strcmp(argv[0], "overflow-buff") == 0) {
@@ -1324,6 +1357,146 @@ static int st_proxyurl(httrackp *opt, int argc, char **argv) {
  return 0;
 }

+/* Scripted SOCKS5 server: no-auth method reply, then a success CONNECT reply
+   carrying the given ATYP address, then a sentinel origin byte the handshake
+   must leave unread (an off-by-one in the reply framing eats it). */
+static size_t socks5_reply(unsigned char *buf, unsigned char atyp,
+                           const unsigned char *addr, size_t addrlen) {
+  size_t n = 0;
+
+  buf[n++] = 0x05;
+  buf[n++] = 0x00; /* method: no authentication */
+  buf[n++] = 0x05;
+  buf[n++] = 0x00; /* REP: succeeded */
+  buf[n++] = 0x00;
+  buf[n++] = atyp;
+  memcpy(buf + n, addr, addrlen);
+  n += addrlen;
+  buf[n++] = 0x1f;
+  buf[n++] = 0x90; /* BND.PORT */
+  buf[n++] = 0xAA; /* sentinel */
+  return n;
+}
+
+#define SOCKS5_SENTINEL_LEFT(io, len) ((io).consumed == (len) - 1)
+
+static int st_socks5(httrackp *opt, int argc, char **argv) {
+  static const unsigned char v4[4] = {127, 0, 0, 1};
+  static const unsigned char v6[16] = {0};
+  static const unsigned char domain[6] = {5, 'p', 'r', 'o', 'x', 'y'};
+  const char *const proxy = "socks5://127.0.0.1";
+  unsigned char script[64];
+  socks5_test_io io;
+  size_t len;
+
+  (void) argc;
+  (void) argv;
+
+  /* each reply address type is drained exactly, sentinel untouched */
+  len = socks5_reply(script, 0x01, v4, sizeof(v4));
+  io.reply = script;
+  io.reply_len = len;
+  assertf(socks5_handshake_scripted(opt, "origin.test", proxy, &io) == 1);
+  assertf(SOCKS5_SENTINEL_LEFT(io, len));
+  /* the greeting offers no-auth only, and the origin goes out by name, port 80
+   */
+  assertf(io.sent_len == 3 + 7 + 11);
+  assertf(memcmp(io.sent, "\x05\x01\x00", 3) == 0);
+  assertf(memcmp(io.sent + 3, "\x05\x01\x00\x03\x0borigin.test\x00\x50", 18) ==
+          0);
+
+  len = socks5_reply(script, 0x04, v6, sizeof(v6));
+  io.reply = script;
+  io.reply_len = len;
+  assertf(socks5_handshake_scripted(opt, "origin.test", proxy, &io) == 1);
+  assertf(SOCKS5_SENTINEL_LEFT(io, len));
+
+  len = socks5_reply(script, 0x03, domain, sizeof(domain));
+  io.reply = script;
+  io.reply_len = len;
+  assertf(socks5_handshake_scripted(opt, "origin.test", proxy, &io) == 1);
+  assertf(SOCKS5_SENTINEL_LEFT(io, len));
+
+  /* an unknown address type has no known length: fail, never guess */
+  len = socks5_reply(script, 0x02, v4, sizeof(v4));
+  io.reply = script;
+  io.reply_len = len;
+  assertf(socks5_handshake_scripted(opt, "origin.test", proxy, &io) == 0);
+
+  /* truncated frames (here: no BND.PORT) fail instead of over-reading */
+  len = socks5_reply(script, 0x01, v4, sizeof(v4)) - 3;
+  io.reply = script;
+  io.reply_len = len;
+  assertf(socks5_handshake_scripted(opt, "origin.test", proxy, &io) == 0);
+
+  /* explicit origin port is encoded big-endian (8443 = 0x20fb) */
+  len = socks5_reply(script, 0x01, v4, sizeof(v4));
+  io.reply = script;
+  io.reply_len = len;
+  assertf(socks5_handshake_scripted(opt, "origin.test:8443", proxy, &io) == 1);
+  assertf(memcmp(io.sent + io.sent_len - 2, "\x20\xfb", 2) == 0);
+
+  /* credentials: split on the first colon of the escaped userinfo, so %3a stays
+     inside the username and a colon in the password is not a delimiter */
+  {
+    static const unsigned char auth_script[] = {
+        0x05, 0x02,             /* method: user/pass */
+        0x01, 0x00,             /* auth: success */
+        0x05, 0x00, 0x00, 0x01, /* REP: succeeded, ATYP ipv4 */
+        127,  0,    0,    1,    0x1f, 0x90, 0xAA};
+
+    io.reply = auth_script;
+    io.reply_len = sizeof(auth_script);
+    assertf(socks5_handshake_scripted(opt, "origin.test",
+                                      "socks5://us%3aer:p:ass@127.0.0.1",
+                                      &io) == 1);
+    assertf(SOCKS5_SENTINEL_LEFT(io, sizeof(auth_script)));
+    assertf(memcmp(io.sent, "\x05\x02\x00\x02", 4) == 0);
+    assertf(memcmp(io.sent + 4, "\x01\x05us:er\x05p:ass", 13) == 0);
+  }
+
+  /* a proxy demanding auth we cannot provide, and one refusing every method */
+  io.reply = (const unsigned char *) "\x05\x02";
+  io.reply_len = 2;
+  assertf(socks5_handshake_scripted(opt, "origin.test", proxy, &io) == 0);
+  io.reply = (const unsigned char *) "\x05\xff";
+  io.reply_len = 2;
+  assertf(socks5_handshake_scripted(opt, "origin.test", proxy, &io) == 0);
+
+  /* a refused CONNECT is an error, not a tunnel */
+  io.reply = (const unsigned char
+                  *) "\x05\x00\x05\x05\x00\x01\x7f\x00\x00\x01\x1f\x90";
+  io.reply_len = 12;
+  assertf(socks5_handshake_scripted(opt, "origin.test", proxy, &io) == 0);
+
+  /* over-long host or credentials are rejected before anything is sent */
+  {
+    char host[512];
+    char name[1024];
+    size_t i;
+
+    host[0] = '\0';
+    for (i = 0; i < 256; i++)
+      strcatbuff(host, "a");
+    io.reply = script;
+    io.reply_len = len;
+    assertf(socks5_handshake_scripted(opt, host, proxy, &io) == 0);
+    assertf(io.sent_len == 0);
+
+    strcpybuff(name, "socks5://user:");
+    for (i = 0; i < 256; i++)
+      strcatbuff(name, "p");
+    strcatbuff(name, "@127.0.0.1");
+    io.reply = script;
+    io.reply_len = len;
+    assertf(socks5_handshake_scripted(opt, "origin.test", name, &io) == 0);
+    assertf(io.sent_len == 0);
+  }
+
+  printf("socks5 self-test OK\n");
+  return 0;
+}
+
 /* Regression for the one-byte fil[] overflow: a 2047-byte hostless "?"-URL used
   to abort in strncat_safe_ when the missing leading '/' pushed fil to 2048. */
 static int st_identabs(httrackp *opt, int argc, char **argv) {
@@ -1468,7 +1641,8 @@ static int st_crange(httrackp *opt, int argc, char **argv) {
  return 0;
 }

-/* Decode a body argument ("hex:FFD8.." or literal text) into buf. */
+/* Decode an argument ("hex:FFD8.." or literal text) into buf. Raw non-UTF-8
+   bytes cannot survive a Windows command line, so hostile inputs go as hex. */
 static size_t st_decode_body(const char *arg, char *buf, size_t size) {
  size_t n = 0;

@@ -1508,6 +1682,94 @@ static int st_sniff(httrackp *opt, int argc, char **argv) {
  return 0;
 }

+/* fsize()/fsize_utf8()/fpsize() must report a size past 4GB: 32-bit wraps both
+   ways there (MSVC's off_t and struct _stat st_size are long, 32-bit even on
+   x64), and a size under 4GB would survive an *unsigned* 32-bit truncation. */
+static int st_fsize(httrackp *opt, int argc, char **argv) {
+  const LLint expected = 5 * 1024 * 1024 * 1024LL;
+  char BIGSTK path[HTS_URLMAXSIZE * 2];
+  char BIGSTK absent[HTS_URLMAXSIZE * 2];
+  /* both variants: only fsize() feeds the >2GB readers (file://, --list) */
+  const int width = (int) sizeof(fsize(""));
+  const int width_utf8 = (int) sizeof(fsize_utf8(""));
+  FILE *fp;
+  LLint got, got_utf8, gotp, gone;
+  int rc = 0;
+
+  (void) opt;
+  if (argc < 1) {
+    fprintf(stderr, "fsize: needs a directory\n");
+    return 1;
+  }
+  concat(path, sizeof(path), argv[0], "/sparse-5g.bin");
+  concat(absent, sizeof(absent), argv[0], "/no-such-file.bin");
+
+  /* sparse: seek past 4GB and write the last byte */
+  fp = FOPEN(path, "wb");
+  if (fp == NULL) {
+    fprintf(stderr, "fsize: cannot create '%s': %s\n", path, strerror(errno));
+    return 1;
+  }
+#ifdef _WIN32
+  {
+    /* NTFS allocates the hole unless asked not to; POSIX gives it for free.
+       Best-effort: a non-sparse file still measures the same, just costs 5GB.
+     */
+    HANDLE h = (HANDLE) _get_osfhandle(_fileno(fp));
+    DWORD ret;
+
+    if (h != INVALID_HANDLE_VALUE)
+      (void) DeviceIoControl(h, FSCTL_SET_SPARSE, NULL, 0, NULL, 0, &ret, NULL);
+  }
+#endif
+  if (fseeko(fp, expected - 1, SEEK_SET) != 0 || fputc(0, fp) == EOF ||
+      fclose(fp) != 0) {
+    fprintf(stderr, "fsize: cannot extend '%s' to " LLintP ": %s\n", path,
+            expected, strerror(errno));
+    UNLINK(path);
+    return 1;
+  }
+
+  got = fsize(path);
+  got_utf8 = fsize_utf8(path);
+  fp = FOPEN(path, "rb");
+  if (fp == NULL) {
+    fprintf(stderr, "fsize: cannot reopen '%s': %s\n", path, strerror(errno));
+    gotp = -1;
+  } else {
+    gotp = fpsize(fp);
+    fclose(fp);
+  }
+  UNLINK(path);
+  gone = fsize(absent); /* contract: -1, not 0, when absent */
+
+  printf("fsize: width=%d,%d size=" LLintP "," LLintP " psize=" LLintP
+         " absent=" LLintP "\n",
+         width, width_utf8, got, got_utf8, gotp, gone);
+  if (width != 8 || width_utf8 != 8) {
+    fprintf(stderr, "fsize: return types are %d/%d bytes, expected 8\n", width,
+            width_utf8);
+    rc = 1;
+  }
+  if (got != expected || got_utf8 != expected) {
+    fprintf(stderr,
+            "fsize: fsize/fsize_utf8 are " LLintP "/" LLintP
+            ", expected " LLintP "\n",
+            got, got_utf8, expected);
+    rc = 1;
+  }
+  if (gotp != expected) {
+    fprintf(stderr, "fsize: fpsize is " LLintP ", expected " LLintP "\n", gotp,
+            expected);
+    rc = 1;
+  }
+  if (gone != -1) {
+    fprintf(stderr, "fsize: absent file is " LLintP ", expected -1\n", gone);
+    rc = 1;
+  }
+  return rc;
+}
+
 static int st_savename(httrackp *opt, int argc, char **argv) {
  lien_adrfilsave afs;
  cache_back cache;
@@ -2654,11 +2916,43 @@ static int st_robots(httrackp *opt, int argc, char **argv) {
  return 0;
 }

+/* Connected stream pair over loopback; Windows has no socketpair(). */
+static int st_socketpair(T_SOC sv[2]) {
+  struct sockaddr_in sa;
+  socklen_t len = sizeof(sa);
+  T_SOC srv, cli, acc;
+
+  memset(&sa, 0, sizeof(sa));
+  sa.sin_family = AF_INET;
+  sa.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
+  if ((srv = (T_SOC) socket(AF_INET, SOCK_STREAM, 0)) == INVALID_SOCKET)
+    return -1;
+  if (bind(srv, (struct sockaddr *) &sa, sizeof(sa)) != 0 ||
+      listen(srv, 1) != 0 ||
+      getsockname(srv, (struct sockaddr *) &sa, &len) != 0) {
+    deletesoc(srv);
+    return -1;
+  }
+  if ((cli = (T_SOC) socket(AF_INET, SOCK_STREAM, 0)) == INVALID_SOCKET) {
+    deletesoc(srv);
+    return -1;
+  }
+  if (connect(cli, (struct sockaddr *) &sa, sizeof(sa)) != 0 ||
+      (acc = (T_SOC) accept(srv, NULL, NULL)) == INVALID_SOCKET) {
+    deletesoc(cli);
+    deletesoc(srv);
+    return -1;
+  }
+  deletesoc(srv);
+  sv[0] = acc;
+  sv[1] = cli;
+  return 0;
+}
+
 /* get_ftp_line must bound a hostile, CRLF-less reply into its internal
   1024-byte buffer; ASan turns the pre-fix overflow into an abort here. */
-#ifndef _WIN32
 static int st_ftpline(httrackp *opt, int argc, char **argv) {
-  int sv[2];
+  T_SOC sv[2];
  char line[2048];
  char flood[4096];

@@ -2666,19 +2960,19 @@ static int st_ftpline(httrackp *opt, int argc, char **argv) {
  (void) argc;
  (void) argv;
  memset(flood, 'x', sizeof(flood));
-  assertf(socketpair(AF_UNIX, SOCK_STREAM, 0, sv) == 0);
-  assertf(write(sv[1], "220 ", 4) == 4); // valid 3-digit code
-  assertf(write(sv[1], flood, sizeof(flood)) == (ssize_t) sizeof(flood));
-  assertf(write(sv[1], "\r\n", 2) == 2); // end the line so we return
-  close(sv[1]);
+  assertf(st_socketpair(sv) == 0);
+  // the 4102-byte reply fits the loopback send buffer, so no reader is needed
+  assertf(send(sv[1], "220 ", 4, 0) == 4); // valid 3-digit code
+  assertf(send(sv[1], flood, (int) sizeof(flood), 0) == (int) sizeof(flood));
+  assertf(send(sv[1], "\r\n", 2, 0) == 2); // end the line so we return
+  deletesoc(sv[1]);
  line[0] = '\0';
  get_ftp_line(sv[0], line, sizeof(line), 5);
-  close(sv[0]);
+  deletesoc(sv[0]);
  printf("ftp-line self-test OK (bounded %d-byte reply)\n",
         (int) sizeof(flood));
  return 0;
 }
-#endif

 /* ftp_split_userpass: well-formed split, plus a hostile over-long userinfo
   that pre-fix overran user[256]/pass[256]. */
@@ -2750,11 +3044,11 @@ static const struct selftest_entry {
    {"redirect-samefile", "", "same-file redirect detection self-test (#159)",
     st_redirect_samefile},
    {"mime", "<filename>", "MIME type for a filename", st_mime},
-    {"charset", "<charset> <string>",
+    {"charset", "<charset> <hex:..|string>",
     "convert a string to UTF-8 from a charset", st_charset},
    {"metacharset", "<html>", "extract the <meta> charset from an HTML page",
     st_metacharset},
-    {"isutf8", "<string>", "is the string valid UTF-8 (1/0)", st_isutf8},
+    {"isutf8", "<hex:..|string>", "is the string valid UTF-8 (1/0)", st_isutf8},
    {"idna-encode", "<host>", "encode a hostname to IDNA/punycode",
     st_idna_encode},
    {"idna-decode", "<host>", "decode an IDNA/punycode hostname",
@@ -2774,6 +3068,8 @@ static const struct selftest_entry {
    {"identurl", "<url>", "split an absolute URL into (adr, fil)", st_identurl},
    {"proxyurl", "<proxy-arg>", "parse a -P proxy URL into host/port",
     st_proxyurl},
+    {"socks5", "", "SOCKS5 handshake framing and credential self-test",
+     st_socks5},
    {"identabs", "", "ident_url_absolute one-byte fil[] overflow self-test",
     st_identabs},
    {"header", "<raw-header-line> ...", "response header-line parsing",
@@ -2789,6 +3085,7 @@ static const struct selftest_entry {
     "local save-name for a URL", st_savename},
    {"sniff", "<content-type> <hex:..|text>", "MIME magic consistency",
     st_sniff},
+    {"fsize", "<dir>", "file size past the 2GB signed-32-bit wrap", st_fsize},
    {"cache", "<dir>", "cache read/write round-trip self-test", st_cache},
    {"cacheindex", "", "cache-index (.ndx) parse must stay in bounds",
     st_cacheindex},
@@ -2819,10 +3116,8 @@ static const struct selftest_entry {
     st_contentcodings},
    {"robots", "", "robots.txt RFC 9309 Allow/Disallow precedence self-test",
     st_robots},
-#ifndef _WIN32
    {"ftp-line", "", "get_ftp_line bounds a hostile FTP reply line",
     st_ftpline},
-#endif
    {"ftp-userpass", "", "ftp_split_userpass bounds URL userinfo", st_ftpuser},
 };

--- a/src/httrack-library.h
+++ b/src/httrack-library.h
@@ -743,7 +743,8 @@ HTSEXT_API hts_boolean hts_findissystem(find_handle find);
 HTSEXT_API FILE *hts_fopen_utf8(const char *path, const char *mode);

 #define STAT hts_stat_utf8
-typedef struct _stat STRUCT_STAT;
+/* _stat64: _stat's st_size is a 32-bit long, even in x64 builds */
+typedef struct _stat64 STRUCT_STAT;

 HTSEXT_API int hts_stat_utf8(const char *path, STRUCT_STAT *buf);

--- a/src/httrack.c
+++ b/src/httrack.c
@@ -45,6 +45,7 @@ Please visit our Website: http://www.httrack.com
 #include "htsdefines.h"
 #include "httrack.h"
 #include "htslib.h"
+#include "htscharset.h" // after htslib.h: winsock2.h must precede windows.h

 /* Static definitions */
 static int fexist(const char *s);
@@ -206,6 +207,7 @@ int main(int argc, char **argv) {
  httrackp *opt;

 #ifdef _WIN32
+  hts_argv_utf8(&argc, &argv);
  {
    WORD wVersionRequested;     // requested version WinSock API
    WSADATA wsadata;            // Windows Sockets API data
--- a/src/libhttrack.vcxproj
+++ b/src/libhttrack.vcxproj
@@ -70,7 +70,7 @@
    <Link>
      <!-- vcpkg auto-links libssl/libcrypto/zlib/brotli/zstd; only the OS import
           lib is explicit. -->
-      <AdditionalDependencies>Ws2_32.lib;%(AdditionalDependencies)</AdditionalDependencies>
+      <AdditionalDependencies>Ws2_32.lib;Shell32.lib;%(AdditionalDependencies)</AdditionalDependencies>
      <GenerateDebugInformation>true</GenerateDebugInformation>
    </Link>
  </ItemDefinitionGroup>
@@ -125,6 +125,7 @@
    <ClCompile Include="htsmodules.c" />
    <ClCompile Include="htsname.c" />
    <ClCompile Include="htsparse.c" />
+    <ClCompile Include="htsproxy.c" />
    <ClCompile Include="htsrobots.c" />
    <ClCompile Include="htsselftest.c" />
    <ClCompile Include="htssniff.c" />
--- a/src/proxy/store.c
+++ b/src/proxy/store.c
@@ -577,9 +577,11 @@ PT_Index PT_LoadCache(const char *filename) {
          chain = coucal_enum_next(&en);
        }
        if (chain != NULL) {
-          if (!link_has_authority(chain->name))
-            strcat(index->slots.common.startUrl, "http://");
-          strcat(index->slots.common.startUrl, chain->name);
+          const char *scheme = link_has_authority(chain->name) ? "" : "http://";
+
+          snprintf(index->slots.common.startUrl,
+                   sizeof(index->slots.common.startUrl), "%s%s", scheme,
+                   (const char *) chain->name);
        }
      }
    }
@@ -632,7 +634,7 @@ int PT_EnumCache(PT_Indexes indexes,
      const long int index_id = (long int) chain->value.intg;
      const char *const url = chain->name;

-      if (index_id >= 0 && index_id <= indexes->index_size) {
+      if (index_id >= 0 && index_id < indexes->index_size) {
        PT_Element item =
          PT_ReadCache(indexes->index[index_id], url,
                       FETCH_HEADERS | FETCH_BODY);
@@ -757,7 +759,7 @@ PT_Element PT_ReadIndex(PT_Indexes indexes, const char *url, int flags) {
    if (strncmp(url, "http://", 7) == 0)
      url += 7;
    if (coucal_read(indexes->cil, url, &index_id)) {
-      if (index_id >= 0 && index_id <= indexes->index_size) {
+      if (index_id >= 0 && index_id < indexes->index_size) {
        PT_Element item = PT_ReadCache(indexes->index[index_id], url, flags);

        if (item != NULL) {
@@ -780,7 +782,7 @@ int PT_LookupIndex(PT_Indexes indexes, const char *url) {
    if (strncmp(url, "http://", 7) == 0)
      url += 7;
    if (coucal_read(indexes->cil, url, &index_id)) {
-      if (index_id >= 0 && index_id <= indexes->index_size) {
+      if (index_id >= 0 && index_id < indexes->index_size) {
        return 1;
      } else {
        proxytrack_print_log(CRITICAL,
@@ -967,10 +969,12 @@ int PT_LoadCache__New(PT_Index index_, const char *filename) {
                /* First link as starting URL */
                if (!firstSeen) {
                  if (strstr(filenameIndex, "/robots.txt") == NULL) {
+                    const char *scheme =
+                        link_has_authority(filenameIndex) ? "" : "http://";
+
                    firstSeen = 1;
-                    if (!link_has_authority(filenameIndex))
-                      strcat(index->startUrl, "http://");
-                    strcat(index->startUrl, filenameIndex);
+                    snprintf(index->startUrl, sizeof(index->startUrl), "%s%s",
+                             scheme, filenameIndex);
                  }
                }
              } else {
@@ -1102,7 +1106,8 @@ static PT_Element PT_ReadCache__New_u(PT_Index index_, const char *url,
                                          && (!isalpha(previous_save_[0]) || previous_save_[1] != ':')) // c:/home/foo/bar.gif
              ) {
              index->safeCache = 1;
-              sprintf(previous_save, "%s%s", index->path, previous_save_);
+              snprintf(previous_save, sizeof(previous_save), "%s%s",
+                       index->path, previous_save_);
            }
            // bogus format (includes buggy absolute path)
            else {
@@ -1127,15 +1132,16 @@ static PT_Element PT_ReadCache__New_u(PT_Index index_, const char *url,
                int saveLen = (int) strlen(previous_save_);

                if (index->fixedPath < saveLen) {
-                  sprintf(previous_save, "%s%s", index->path,
-                          previous_save_ + index->fixedPath);
+                  snprintf(previous_save, sizeof(previous_save), "%s%s",
+                           index->path, previous_save_ + index->fixedPath);
                } else {
                  snprintf(r->msg, sizeof(r->msg), "Bogus fixePath prefix for %s (prefixLen=%d)",
                          previous_save_, (int) index->fixedPath);
                  r->statuscode = STATUSCODE_INVALID;
                }
              } else {
-                sprintf(previous_save, "%s%s", index->path, previous_save_);
+                snprintf(previous_save, sizeof(previous_save), "%s%s",
+                         index->path, previous_save_);
              }
            }
          }
@@ -1348,45 +1354,71 @@ static int PT_SaveCache__New(PT_Indexes indexes, const char *filename) {
 /* Old HTTrack cache (dat/ndx) format                           */
 /* ------------------------------------------------------------ */

-static int cache_brstr(char *adr, char *s) {
+static int cache_brstr(char *adr, char *s, size_t s_size) {
  int i;
  int off;
-  char buff[256 + 1];
+  char buff[256 + 4];

  off = binput(adr, buff, 256);
-  adr += off;
-  sscanf(buff, "%d", &i);
-  if (i > 0)
-    strncpy(s, adr, i);
-  *(s + i) = '\0';
-  off += i;
+  /* binput stops at adr's terminating NUL; a value only follows a real line
+     terminator, so never step past end-of-buffer. */
+  if (adr[off - 1] == '\0') {
+    s[0] = '\0';
+    return off - 1;
+  }
+  /* an empty/non-numeric field leaves i unset: treat as length 0 */
+  if (sscanf(buff, "%d", &i) != 1 || i < 0 || i > 32768)
+    i = 0;
+  if (i > 0) {
+    /* a corrupt cache may declare a length past the buffer end; bound the copy
+       and the advance to the bytes actually present */
+    const size_t avail = strnlen(adr + off, (size_t) i);
+    const size_t store = avail < s_size ? avail : s_size - 1;
+
+    memcpy(s, adr + off, store);
+    s[store] = '\0';
+    off += (int) avail;
+  } else {
+    s[0] = '\0';
+  }
  return off;
 }

-static void cache_rstr(FILE * fp, char *s) {
-  INTsys i;
+static void cache_rstr(FILE *fp, char *s, size_t s_size) {
+  INTsys i = 0;
  char buff[256 + 4];

  linput(fp, buff, 256);
-  sscanf(buff, INTsysP, &i);
-  if (i < 0 || i > 32768)       /* error, something nasty happened */
+  /* an unmatched sscanf leaves i untouched: length 0, not a stack value */
+  if (sscanf(buff, INTsysP, &i) != 1 || i < 0 || i > 32768)
    i = 0;
  if (i > 0) {
-    if ((int) fread(s, 1, i, fp) != i) {
+    /* store at most s_size-1 bytes, but consume all i bytes so the next field
+       stays aligned when a tampered cache declares more than the destination
+       holds */
+    const size_t want = (size_t) i;
+    const size_t store = want < s_size ? want : s_size - 1;
+
+    if (fread(s, 1, store, fp) != store) {
      assertf(! "fread_cache_failed");
    }
+    if (want > store && fseek(fp, (long) (want - store), SEEK_CUR) != 0) {
+      assertf(!"fseek_cache_failed");
+    }
+    s[store] = '\0';
+  } else {
+    s[0] = '\0';
  }
-  *(s + i) = '\0';
 }

 static char *cache_rstr_addr(FILE * fp) {
-  INTsys i;
+  INTsys i = 0;
  char *addr = NULL;
  char buff[256 + 4];

  linput(fp, buff, 256);
-  sscanf(buff, "%d", &i);
-  if (i < 0 || i > 32768)       /* error, something nasty happened */
+  /* an unmatched sscanf leaves i untouched: length 0, not a stack value */
+  if (sscanf(buff, INTsysP, &i) != 1 || i < 0 || i > 32768)
    i = 0;
  if (i > 0) {
    addr = malloc(i + 1);
@@ -1400,19 +1432,31 @@ static char *cache_rstr_addr(FILE * fp) {
  return addr;
 }

+/* Allocate n+1 bytes for an n-byte cache body, rejecting a hostile/corrupt
+   length that would demand an absurd allocation or wrap n+1. NULL on refuse. */
+static char *cache_alloc_body(size_t n) {
+  if (n >= (size_t) INT32_MAX)
+    return NULL;
+  return (char *) malloc(n + 1);
+}
+
 static void cache_rint(FILE * fp, int *i) {
  char s[256];

-  cache_rstr(fp, s);
-  sscanf(s, "%d", i);
+  cache_rstr(fp, s, sizeof(s));
+  if (sscanf(s, "%d", i) != 1)
+    *i = 0;
 }

 static void cache_rLLint(FILE * fp, unsigned long *i) {
  int l;
  char s[256];

-  cache_rstr(fp, s);
-  sscanf(s, "%d", &l);
+  cache_rstr(fp, s, sizeof(s));
+  /* reject a non-numeric or negative field: a negative length cast to unsigned
+     would wrap a later malloc(size+1) to a tiny buffer */
+  if (sscanf(s, "%d", &l) != 1 || l < 0)
+    l = 0;
  *i = (unsigned long) l;
 }

@@ -1472,12 +1516,12 @@ static int PT_LoadCache__Old(PT_Index index_, const char *filename) {
        char *a = use;

        use[ndxSize] = '\0';
-        a += cache_brstr(a, firstline);
+        a += cache_brstr(a, firstline, sizeof(firstline));
        if (strncmp(firstline, "CACHE-", 6) == 0) {     // Nouvelle version du cache
          if (strncmp(firstline, "CACHE-1.", 8) == 0) { // Version 1.1x
            cache->version = (int) (firstline[8] - '0');        // cache 1.x
            if (cache->version <= 5) {
-              a += cache_brstr(a, firstline);
+              a += cache_brstr(a, firstline, sizeof(firstline));
              strcpy(cache->lastmodified, firstline);
            } else {
              fclose(cache->dat);
@@ -1523,11 +1567,12 @@ static int PT_LoadCache__Old(PT_Index index_, const char *filename) {
              if (!firstSeen) {
                if (strstr(line, "/robots.txt") == NULL) {
                  PT_Index__Old index = cache;
+                  const char *scheme =
+                      link_has_authority(line) ? "" : "http://";

                  firstSeen = 1;
-                  if (!link_has_authority(line))
-                    strcat(index->startUrl, "http://");
-                  strcat(index->startUrl, line);
+                  snprintf(index->startUrl, sizeof(index->startUrl), "%s%s",
+                           scheme, line);
                }
              }

@@ -1623,9 +1668,13 @@ static PT_Element PT_ReadCache__Old_u(PT_Index index_, const char *url,
          String urlDecoded;

          r->statuscode = old_r.statuscode;
-          r->size = old_r.size; // taille fichier
-          strcpy(r->msg, old_r.msg);
-          strcpy(r->contenttype, old_r.contenttype);
+          r->size = old_r.size > 0 ? (size_t) old_r.size : 0; // taille fichier
+          /* these fixed fields come straight from fread and carry no guaranteed
+             NUL; terminate them before the bounded copy */
+          old_r.msg[sizeof(old_r.msg) - 1] = '\0';
+          old_r.contenttype[sizeof(old_r.contenttype) - 1] = '\0';
+          strcpybuff(r->msg, old_r.msg);
+          strcpybuff(r->contenttype, old_r.contenttype);

          /* Guess the destination filename.. this sucks, because this method is not reliable.
             Yes, the old 1.0 cache format was *that* bogus. /rx */
@@ -1666,26 +1715,27 @@ static PT_Element PT_ReadCache__Old_u(PT_Index index_, const char *url,
        cache_rint(cache->dat, &r->statuscode);
        cache_rLLint(cache->dat, &size_);
        r->size = (size_t) size_;
-        cache_rstr(cache->dat, r->msg);
-        cache_rstr(cache->dat, r->contenttype);
+        cache_rstr(cache->dat, r->msg, sizeof(r->msg));
+        cache_rstr(cache->dat, r->contenttype, sizeof(r->contenttype));
        if (cache->version >= 3)
-          cache_rstr(cache->dat, r->charset);
-        cache_rstr(cache->dat, r->lastmodified);
-        cache_rstr(cache->dat, r->etag);
-        cache_rstr(cache->dat, r->location);
+          cache_rstr(cache->dat, r->charset, sizeof(r->charset));
+        cache_rstr(cache->dat, r->lastmodified, sizeof(r->lastmodified));
+        cache_rstr(cache->dat, r->etag, sizeof(r->etag));
+        cache_rstr(cache->dat, r->location, sizeof(location_default));
        if (cache->version >= 2)
-          cache_rstr(cache->dat, r->cdispo);
+          cache_rstr(cache->dat, r->cdispo, sizeof(r->cdispo));
        if (cache->version >= 4) {
-          cache_rstr(cache->dat, previous_save_);       // adr
-          cache_rstr(cache->dat, previous_save_);       // fil
+          cache_rstr(cache->dat, previous_save_, sizeof(previous_save_)); // adr
+          cache_rstr(cache->dat, previous_save_, sizeof(previous_save_)); // fil
          previous_save[0] = '\0';
-          cache_rstr(cache->dat, previous_save_);       // save
+          cache_rstr(cache->dat, previous_save_,
+                     sizeof(previous_save_)); // save
        }
        if (cache->version >= 5) {
          r->headers = cache_rstr_addr(cache->dat);
        }
        //
-        cache_rstr(cache->dat, check);
+        cache_rstr(cache->dat, check, sizeof(check));
        if (strcmp(check, "HTS") == 0) {        /* intégrité OK */
          ok = 1;
        }
@@ -1714,7 +1764,8 @@ static PT_Element PT_ReadCache__Old_u(PT_Index index_, const char *url,
                                        && (!isalpha(previous_save_[0]) || previous_save_[1] != ':'))   // c:/home/foo/bar.gif
            ) {
            index->safeCache = 1;
-            sprintf(previous_save, "%s%s", index->path, previous_save_);
+            snprintf(previous_save, sizeof(previous_save), "%s%s", index->path,
+                     previous_save_);
          }
          // bogus format (includes buggy absolute path)
          else {
@@ -1739,15 +1790,16 @@ static PT_Element PT_ReadCache__Old_u(PT_Index index_, const char *url,
              int saveLen = (int) strlen(previous_save_);

              if (index->fixedPath < saveLen) {
-                sprintf(previous_save, "%s%s", index->path,
-                        previous_save_ + index->fixedPath);
+                snprintf(previous_save, sizeof(previous_save), "%s%s",
+                         index->path, previous_save_ + index->fixedPath);
              } else {
                snprintf(r->msg, sizeof(r->msg), "Bogus fixePath prefix for %s (prefixLen=%d)",
                        previous_save_, (int) index->fixedPath);
                r->statuscode = STATUSCODE_INVALID;
              }
            } else {
-              sprintf(previous_save, "%s%s", index->path, previous_save_);
+              snprintf(previous_save, sizeof(previous_save), "%s%s",
+                       index->path, previous_save_);
            }
          }
        }
@@ -1764,7 +1816,7 @@ static PT_Element PT_ReadCache__Old_u(PT_Index index_, const char *url,
              FILE *fp = fopen(previous_save, "rb");

              if (fp != NULL) {
-                r->adr = (char *) malloc(r->size + 1);
+                r->adr = cache_alloc_body(r->size);
                if (r->adr != NULL) {
                  if (r->size > 0 && fread(r->adr, 1, r->size, fp) != r->size) {
                    r->statuscode = STATUSCODE_INVALID;
@@ -1784,7 +1836,7 @@ static PT_Element PT_ReadCache__Old_u(PT_Index index_, const char *url,
          } else {
            // lire fichier (d'un coup)
            if (flags & FETCH_BODY) {
-              r->adr = (char *) malloc(r->size + 1);
+              r->adr = cache_alloc_body(r->size);
              if (r->adr != NULL) {
                if (fread(r->adr, 1, r->size, cache->dat) != r->size) { // erreur
                  free(r->adr);
--- a/tests/01_engine-charset.test
+++ b/tests/01_engine-charset.test
@@ -23,7 +23,7 @@ conv 'iso-8859-1' 'café' 'cafÃ©'

 # windows-1252 is NOT latin-1: 0x80 is the euro sign, not U+0080. This is the
 # case that actually exercises the cp1252 table (the 0x80-0x9F range).
-conv 'windows-1252' $'\x80' '€'
+conv 'windows-1252' 'hex:80' '€'

 # pure ASCII is charset-invariant
 conv 'us-ascii' 'hello' 'hello'
@@ -34,8 +34,8 @@ conv 'no-such-charset-xyz' 'abc' 'abc'
 test "$(httrack -O /dev/null -#test=charset 'no-such-charset-xyz' 'café' 2>/dev/null)" == "" || exit 1

 # malformed UTF-8 (lone continuation byte, truncated lead byte) must not crash
-runs 'utf-8' $'\x80'
-runs 'utf-8' $'\xc3'
+runs 'utf-8' 'hex:80'
+runs 'utf-8' 'hex:c3'

 # hts_getCharsetFromMeta: <meta> charset extraction, HTML5 and legacy forms.
 # -#test=metacharset <html> prints the charset, or "(none)".
@@ -89,11 +89,11 @@ utf8() {
 utf8 'plain' '1'
 utf8 'café' '1'
 utf8 '统计' '1'
-utf8 "$(printf 'caf\xe9')" '0'              # latin-1 accent
-utf8 "$(printf '\xc3')" '0'                 # truncated lead byte
-utf8 "$(printf '\xa9')" '0'                 # lone continuation byte
-utf8 "$(printf '\xf0\x9f\x98\x80')" '1'     # 4-byte emoji
-utf8 "$(printf '\xc0\xaf')" '0'             # overlong (latin-1 "À¯" must stay convertible)
-utf8 "$(printf '\xed\xa0\x80')" '0'         # UTF-16 surrogate
-utf8 "$(printf '\xf4\x90\x80\x80')" '0'     # above U+10FFFF
-utf8 "$(printf '\xf8\x88\x80\x80\x80')" '0' # legacy 5-byte form
+utf8 'hex:636166e9' '0'   # latin-1 accent
+utf8 'hex:c3' '0'         # truncated lead byte
+utf8 'hex:a9' '0'         # lone continuation byte
+utf8 'hex:f09f9880' '1'   # 4-byte emoji
+utf8 'hex:c0af' '0'       # overlong (latin-1 "À¯" must stay convertible)
+utf8 'hex:eda080' '0'     # UTF-16 surrogate
+utf8 'hex:f4908080' '0'   # above U+10FFFF
+utf8 'hex:f888808080' '0' # legacy 5-byte form
--- a/tests/01_engine-filelist.test
+++ b/tests/01_engine-filelist.test
@@ -52,14 +52,15 @@ run "$tmp/dir" "$tmp/adir"
 loghas 'Could not include URL list "[^"]+": not a regular file'

 # unreadable regular file: the fopen() errno arm fires, distinct from the
-# directory branch. Root bypasses mode 000, so skip it there.
-if test "$(id -u)" -ne 0; then
-    : >"$tmp/noperm.txt"
-    chmod 000 "$tmp/noperm.txt"
+# directory branch. Needs an OS that enforces mode 000: root bypasses it, and
+# Windows ignores chmod entirely, so probe rather than assume.
+: >"$tmp/noperm.txt"
+chmod 000 "$tmp/noperm.txt"
+if ! cat "$tmp/noperm.txt" >/dev/null 2>&1; then
    run "$tmp/perm" "$tmp/noperm.txt"
-    chmod 644 "$tmp/noperm.txt"
    loghas 'Could not include URL list "[^"]+": .+'
    lognot 'not a regular file'
 fi
+chmod 644 "$tmp/noperm.txt"

 exit 0
--- a/tests/01_engine-filter.test
+++ b/tests/01_engine-filter.test
@@ -193,5 +193,13 @@ test "$(with_timeout httrack -O /dev/null -#test=filter "$pat" "$subj")" == "$su
 match '*[aX]X*[a]Y' 'aXaXaY'
 nomatch '*[aX]X*[a]Y' 'aXbXaY'

-# hostile patterns must not stack-overflow or hang: length + work caps
+# hostile patterns must not stack-overflow or hang: length + depth + work caps
 test "$(with_timeout httrack -O /dev/null -#test=filterbounds)" == "filterbounds: OK" || exit 1
+
+# and the depth cap must hold on the 1MB stack a Windows thread gets (#574):
+# uncapped, the same pattern recursed ~900KB deep. Skipped where 512K is too
+# small to even start the binary.
+if (ulimit -s 512 && httrack --version >/dev/null 2>&1); then
+    out=$(ulimit -s 512 && with_timeout httrack -O /dev/null -#test=filterbounds)
+    test "$out" == "filterbounds: OK" || exit 1
+fi
--- a/tests/01_engine-fsize.test
+++ b/tests/01_engine-fsize.test
@@ -0,0 +1,18 @@
+#!/bin/bash
+#
+# File sizes past the 32-bit wrap ('httrack -#test=fsize <dir>'). 5GB, so a
+# signed *and* an unsigned truncation both show up; sparse, so it costs no disk.
+
+set -euo pipefail
+
+dir=$(mktemp -d)
+trap 'rm -rf "$dir"' EXIT
+
+out=$(httrack -#test=fsize "$dir")
+echo "$out"
+
+want="fsize: width=8,8 size=5368709120,5368709120 psize=5368709120 absent=-1"
+test "$out" == "$want" || {
+    echo "FAIL: unexpected size report (want '$want')"
+    exit 1
+}
--- a/tests/01_engine-idna.test
+++ b/tests/01_engine-idna.test
@@ -38,4 +38,7 @@ dec 'xn--!!!' '㚯'
 dec 'xn--already-encoded.com' 'ǮalǭǮreaǭǫdy.com'

 # second label has a truncated UTF-8 sequence: used to leak the segment buffer.
-enc_bad "$(printf 'b\xc3\xbcchev.\xe4\xbe\x8b\xe5\xad\x62\xc3\xbccheple')"
+# Fed as hex: the raw bytes must reach the encoder intact, but invalid UTF-8
+# cannot survive a Windows command line (it round-trips through UTF-16 to valid
+# U+FFFD, which then encodes fine instead of being rejected).
+enc_bad 'hex:62c3bc636865762ee4be8be5ad62c3bc636865706c65'
--- a/tests/01_engine-rcfile.test
+++ b/tests/01_engine-rcfile.test
@@ -32,6 +32,13 @@ esac
 tmp=$(mktemp -d "${TMPDIR:-/tmp}/httrack_rcfile.XXXXXX") || exit 1
 trap 'rm -rf "$tmp"' EXIT HUP INT QUIT PIPE TERM

+# HTS_HTTRACKRC is ".httrackrc" on POSIX but "httrackrc" on Windows: write both,
+# each platform reads the one it knows.
+write_rc() {
+    cat >"$1/.httrackrc"
+    cp "$1/.httrackrc" "$1/httrackrc"
+}
+
 # --- 1. alias token survives the bound intact -------------------------------
 d1="$tmp/intact"
 mkdir -p "$d1"
@@ -40,7 +47,7 @@ echo '<html><body>hello</body></html>' >"$d1/index.html"
 # optinclude_file() lowercases each config line, so the marker is lowercase to
 # survive the comparison verbatim.
 marker='zzz_rcfile_marker_0123456789_abcdefghijklmnopqrstuvwxyz_intact'
-printf 'user-agent=%s\n' "$marker" >"$d1/.httrackrc"
+printf 'user-agent=%s\n' "$marker" | write_rc "$d1"

 # Run with no -O so the working-directory .httrackrc is loaded (an -O path makes
 # the engine skip the rc files). Output lands in the temp dir. Guard the run so a
@@ -73,7 +80,7 @@ echo '<html><body>hi</body></html>' >"$d2/index.html"
 val=$(printf 'a%.0s' $(seq 1 200))
 for _ in $(seq 1 400); do
    printf 'user-agent=%s\n' "$val"
-done >"$d2/.httrackrc"
+done | write_rc "$d2"

 # The process aborts (httrack turns the fatal signal into exit 134 either way),
 # so the exit code does not distinguish the bounded abort from a heap overflow;
--- a/tests/01_engine-sniff.test
+++ b/tests/01_engine-sniff.test
@@ -35,7 +35,8 @@ chk image/avif hex:0000001C6674797061766966 "$yes"
 chk image/avif hex:0000001C6674797068656963 "$no" # heic brand is not avif
 chk image/heic hex:0000001C6674797068656963 "$yes"
 chk image/svg+xml '<svg xmlns="x">' "$yes"
-chk image/svg+xml $'\xef\xbb\xbf  <?xml version="1.0"?>' "$yes" # BOM+ws skip
+# BOM+ws skip; hex, as Windows argv cannot carry the raw BOM through the ANSI codepage
+chk image/svg+xml hex:EFBBBF20203C3F786D6C2076657273696F6E3D22312E30223F3E "$yes"

 # audio / video
 chk audio/mpeg 'ID3xxx' "$yes"
--- a/tests/01_engine-socks5.test
+++ b/tests/01_engine-socks5.test
@@ -0,0 +1,9 @@
+#!/bin/bash
+#
+
+set -euo pipefail
+
+# The SOCKS5 handshake framing and credential split, driven against scripted
+# server replies (frame draining, oversize rejects, RFC 1929 fields).
+
+httrack -O /dev/null '-#test=socks5' | grep -q "socks5 self-test OK"
--- a/tests/01_engine-strsafe.test
+++ b/tests/01_engine-strsafe.test
@@ -32,10 +32,10 @@ case "$err" in
 esac

 # Same guarantee for the htsbuff builder. The source is exactly the buffer
-# capacity (4 bytes into a 4-byte buffer), so this also pins the boundary: a
+# capacity (6 bytes into a 6-byte buffer), so this also pins the boundary: a
 # '<=' off-by-one in the capacity check would let it through (and print "NOT
 # aborted"). Match the specific htsbuff abort message, not just any assert.
-err=$(httrack -#test=strsafe overflow-buff "abcd" 2>&1) || true
+err=$(httrack -#test=strsafe overflow-buff "abcdef" 2>&1) || true
 case "$err" in
 *"strsafe: NOT aborted"*)
    echo "htsbuff over-capacity write was NOT caught" >&2
--- a/tests/52_local-socks5.test
+++ b/tests/52_local-socks5.test
@@ -0,0 +1,211 @@
+#!/bin/bash
+#
+# Issue #563: a SOCKS5 proxy must carry both http and https, resolve the origin
+# name REMOTELY (ATYP=domain, never a local lookup), and authenticate per RFC
+# 1929 without leaking the credentials to the origin.
+
+set -euo pipefail
+
+: "${top_srcdir:=..}"
+
+if test "${HTTPS_SUPPORT:-}" == "no"; then
+    echo "no https support compiled, skipping"
+    exit 77
+fi
+if ! command -v python3 >/dev/null 2>&1 || ! command -v openssl >/dev/null 2>&1; then
+    echo "python3/openssl missing, skipping"
+    exit 77
+fi
+
+# a .invalid name never resolves (RFC 6761): reaching the page at all proves the
+# proxy did the DNS
+host="socks-origin.invalid"
+server="$top_srcdir/tests/socks5-server.py"
+tmpdir=$(mktemp -d)
+pids=
+
+cleanup() {
+    for pid in $pids; do
+        kill "$pid" 2>/dev/null || true
+    done
+    rm -rf "$tmpdir"
+}
+trap cleanup EXIT
+
+openssl req -x509 -newkey rsa:2048 -keyout "$tmpdir/key.pem" \
+    -out "$tmpdir/cert.pem" -days 2 -nodes -subj "/CN=127.0.0.1" \
+    >/dev/null 2>&1
+cat "$tmpdir/key.pem" "$tmpdir/cert.pem" >"$tmpdir/both.pem"
+
+# start_server <logdir> <mode>: sets $tls_port/$http_port/$socks_port
+start_server() {
+    local dir="$1" mode="$2" ports
+    mkdir -p "$dir"
+    ports="$dir/ports.txt"
+    python3 "$server" "$tmpdir/both.pem" "$dir" "$mode" \
+        >"$ports" 2>"$dir/server.err" &
+    pids="$pids $!"
+    for _ in $(seq 1 100); do
+        grep -q "^ready" "$ports" 2>/dev/null && break
+        sleep 0.1
+    done
+    grep -q "^ready" "$ports" 2>/dev/null || {
+        echo "server ($mode) did not start" >&2
+        cat "$dir/server.err" >&2
+        exit 1
+    }
+    tls_port=$(awk '/^TLS/{print $2}' "$ports")
+    http_port=$(awk '/^HTTP/{print $2}' "$ports")
+    socks_port=$(awk '/^SOCKS/{print $2}' "$ports")
+}
+
+# kill a hung httrack so a missing read bound surfaces as $HANG_RC instead of
+# stalling the job (macOS has no `timeout`)
+HANG_RC=137 # 128 + SIGKILL
+run_crawl() {
+    local out="$1" url="$2" proxy="$3"
+    shift 3
+    local extra="$*"
+    test -n "$extra" || extra="-r1 -s0"
+    rm -rf "$out"
+    # shellcheck disable=SC2086
+    httrack "$url" --proxy "$proxy" \
+        -O "$out" $extra --timeout=10 >"$out.log" 2>&1 &
+    local pid=$!
+    (sleep 60 && kill -9 "$pid" 2>/dev/null) &
+    local guard=$!
+    local rc=0
+    wait "$pid" 2>/dev/null || rc=$?
+    kill "$guard" 2>/dev/null || true
+    wait "$guard" 2>/dev/null || true
+    return "$rc"
+}
+
+# --- https over socks, remote DNS -------------------------------------------
+ok="$tmpdir/ok"
+start_server "$ok" ok
+
+run_crawl "$ok/out" "https://${host}:${tls_port}/" "socks5://127.0.0.1:${socks_port}"
+grep -rq "ORIGIN-PAGE-563" "$ok/out" || {
+    echo "FAIL: origin page not downloaded through the socks proxy" >&2
+    cat "$ok/out.log" "$ok/server.err" >&2
+    exit 1
+}
+grep -q "^ATYP domain ${host}\$" "$ok/socks.log" || {
+    echo "FAIL: proxy did not receive ATYP=domain ${host} (no remote DNS)" >&2
+    cat "$ok/socks.log" >&2
+    exit 1
+}
+# a client that resolved locally would have sent an address, not a name
+grep -q "^ATYP ipv4" "$ok/socks.log" && {
+    echo "FAIL: httrack resolved locally and sent an IPv4 to the proxy" >&2
+    cat "$ok/socks.log" >&2
+    exit 1
+}
+echo "OK: https tunneled through socks5 with remote DNS"
+
+# --- plain http over socks --------------------------------------------------
+: >"$ok/origin-headers.log" # the https crawl above also logged a request line
+run_crawl "$ok/outh" "http://${host}:${http_port}/" "socks5://127.0.0.1:${socks_port}"
+grep -rq "ORIGIN-PAGE-563" "$ok/outh" || {
+    echo "FAIL: plain http not tunneled through the socks proxy" >&2
+    cat "$ok/outh.log" "$ok/socks.log" >&2
+    exit 1
+}
+# the tunneled request is origin-form, as on a direct connection: the http-proxy
+# absolute URI would reach the origin as "GET http://host/"
+grep -q "^REQUEST GET / " "$ok/origin-headers.log" || {
+    echo "FAIL: tunneled request is not origin-form" >&2
+    cat "$ok/origin-headers.log" >&2
+    exit 1
+}
+grep -q "^REQUEST GET http" "$ok/origin-headers.log" && {
+    echo "FAIL: absolute-URI request sent through the socks tunnel" >&2
+    cat "$ok/origin-headers.log" >&2
+    exit 1
+}
+echo "OK: plain http tunneled through socks5"
+
+# --- keep-alive socket reuse must NOT re-run the handshake ------------------
+# A reused keep-alive socket is already tunneled; re-injecting the SOCKS
+# greeting corrupts the origin stream. -c1 + the origin's max>1 advert makes
+# httrack serve the whole plain-http crawl over one tunnel: exactly one
+# handshake, every subpage intact.
+ka="$tmpdir/ka"
+start_server "$ka" ok
+run_crawl "$ka/out" "http://${host}:${http_port}/" "socks5://127.0.0.1:${socks_port}" -r3 -c1
+missing=0
+for i in 1 2 3 4 5; do
+    grep -rq "SUBPAGE-563 /p${i}.html" "$ka/out" || missing=1
+done
+test "$missing" -eq 0 || {
+    echo "FAIL: a keep-alive subpage was lost (re-handshake corrupted the reused socket)" >&2
+    cat "$ka/out.log" "$ka/socks.log" >&2
+    exit 1
+}
+handshakes=$(grep -c "^CMD " "$ka/socks.log" || true)
+test "$handshakes" -eq 1 || {
+    echo "FAIL: expected 1 SOCKS handshake for the reused socket, got $handshakes" >&2
+    cat "$ka/socks.log" >&2
+    exit 1
+}
+echo "OK: keep-alive socket reused over one socks tunnel, no re-handshake"
+
+# --- authenticated socks (RFC 1929) -----------------------------------------
+# over plain http: that is the request an http proxy would decorate with
+# Proxy-Authorization, so the no-leak check below has teeth
+auth="$tmpdir/auth"
+start_server "$auth" ok
+run_crawl "$auth/out" "http://${host}:${http_port}/" \
+    "socks5://user:secret@127.0.0.1:${socks_port}"
+grep -rq "ORIGIN-PAGE-563" "$auth/out" || {
+    echo "FAIL: origin not downloaded through the authenticated socks proxy" >&2
+    cat "$auth/out.log" "$auth/socks.log" >&2
+    exit 1
+}
+grep -q "^METHOD userpass\$" "$auth/socks.log" || {
+    echo "FAIL: user/pass method not negotiated (auth ignored)" >&2
+    cat "$auth/socks.log" >&2
+    exit 1
+}
+grep -q "^AUTH user secret\$" "$auth/socks.log" || {
+    echo "FAIL: wrong socks credentials sent" >&2
+    cat "$auth/socks.log" >&2
+    exit 1
+}
+grep -qi "secret\|proxy-authorization" "$auth/origin-headers.log" && {
+    echo "FAIL: socks credentials leaked into the origin request" >&2
+    cat "$auth/origin-headers.log" >&2
+    exit 1
+}
+echo "OK: socks5 user/pass negotiated, creds not leaked to origin"
+
+# --- hostile: refusing proxy ------------------------------------------------
+ref="$tmpdir/refuse"
+start_server "$ref" refuse
+rc=0
+run_crawl "$ref/out" "https://${host}:${tls_port}/" "socks5://127.0.0.1:${socks_port}" || rc=$?
+test "$rc" -ne "$HANG_RC" || {
+    echo "FAIL: crawl hung on a refusing socks proxy" >&2
+    exit 1
+}
+grep -rq "ORIGIN-PAGE-563" "$ref/out" 2>/dev/null && {
+    echo "FAIL: refusing proxy unexpectedly served the page" >&2
+    exit 1
+}
+echo "OK: refusing socks proxy fails cleanly, no hang"
+
+# --- hostile: truncated handshake reply -------------------------------------
+trunc="$tmpdir/trunc"
+start_server "$trunc" truncate
+rc=0
+run_crawl "$trunc/out" "https://${host}:${tls_port}/" "socks5://127.0.0.1:${socks_port}" || rc=$?
+test "$rc" -ne "$HANG_RC" || {
+    echo "FAIL: crawl hung on a truncated socks reply (bounded read missing)" >&2
+    exit 1
+}
+grep -rq "ORIGIN-PAGE-563" "$trunc/out" 2>/dev/null && {
+    echo "FAIL: truncated-reply proxy unexpectedly served the page" >&2
+    exit 1
+}
+echo "OK: bounded socks handshake, no hang on a truncated reply"
--- a/tests/53_local-proxytrack-cache-corrupt.test
+++ b/tests/53_local-proxytrack-cache-corrupt.test
@@ -0,0 +1,21 @@
+#!/bin/bash
+# A corrupt proxytrack .ndx must not overflow the fixed cache-read buffers. The
+# sanitizer CI build turns any regression here into a hard stack/heap overflow.
+
+set -euo pipefail
+
+dir=$(mktemp -d)
+trap 'rm -rf "$dir"' EXIT
+
+# The first length-prefixed field declares far more than firstline[256] holds;
+# cache_brstr must clamp the copy to the destination, not the declared length.
+{
+    printf '4000\n'
+    head -c 4000 /dev/zero | tr '\0' 'A'
+} >"$dir/foo.ndx"
+: >"$dir/foo.dat" # cache_brstr runs only when the sibling .dat opens
+
+proxytrack --convert "$dir/out.arc" "$dir/foo.ndx" >/dev/null 2>&1 || {
+    echo "FAIL: proxytrack crashed/errored on a corrupt cache index"
+    exit 1
+}
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -2,7 +2,7 @@
 # explicitly: automake does not expand wildcards in EXTRA_DIST, so a glob would
 # silently drop it from the dist tarball and break "make distcheck".
 EXTRA_DIST = $(TESTS) crawl-test.sh run-all-tests.sh check-network.sh \
-	proxy-https-server.py \
+	proxy-https-server.py socks5-server.py \
 	local-crawl.sh local-server.py server.crt server.key \
 	server-root/simple/basic.html server-root/simple/link.html \
 	server-root/stripquery/index.html server-root/stripquery/a.html \
@@ -47,6 +47,7 @@ TESTS = \
 	01_engine-idna.test \
 	01_engine-identurl.test \
 	01_engine-proxyurl.test \
+	01_engine-socks5.test \
 	01_engine-identabs.test \
 	01_engine-escape-room.test \
 	01_engine-inplace-escape.test \
@@ -56,6 +57,7 @@ TESTS = \
 	01_engine-pause.test \
 	01_engine-rcfile.test \
 	01_engine-reconcile.test \
+	01_engine-fsize.test \
 	01_engine-redirect.test \
 	01_engine-relative.test \
 	01_engine-robots.test \
@@ -126,6 +128,8 @@ TESTS = \
 	48_local-crange-memresume.test \
 	49_local-cookiewall.test \
 	50_local-contentcodings.test \
-	51_local-update-codec.test
+	51_local-update-codec.test \
+	52_local-socks5.test \
+	53_local-proxytrack-cache-corrupt.test

 CLEANFILES = check-network_sh.cache
--- a/tests/socks5-server.py
+++ b/tests/socks5-server.py
@@ -0,0 +1,228 @@
+#!/usr/bin/env python3
+"""Local SOCKS5 proxy (RFC 1928/1929) + TLS and plain HTTP origins for #563.
+
+Logs the auth method, any user/pass, and the CONNECT ATYP + literal domain, so
+the test proves httrack sent a hostname (remote DNS) and negotiated auth.
+Modes (argv[3]): ok | refuse (REP=5) | truncate (partial reply, must not hang).
+Usage: socks5-server.py <cert.pem> <logdir> [mode]
+Prints "TLS <port>", "HTTP <port>", "SOCKS <port>", "ready" on stdout.
+"""
+import http.server
+import os
+import socket
+import socketserver
+import ssl
+import struct
+import sys
+import threading
+
+# The one name the proxy answers for; a .invalid TLD never resolves (RFC 6761),
+# so a locally-resolving client could not reach us -- success proves remote DNS.
+REMOTE_HOST = b"socks-origin.invalid"
+# index links the subpages so an -r3 crawl reuses one keep-alive socket
+LINKS = "".join('<a href="/p%d.html">%d</a>' % (i, i) for i in range(1, 6))
+ORIGIN_BODY = ("<html><body>ORIGIN-PAGE-563 " + LINKS + "</body></html>").encode()
+SOCKS_LOG = "socks.log"
+ORIGIN_LOG = "origin-headers.log"
+
+
+def make_origin(logdir):
+    class Origin(http.server.BaseHTTPRequestHandler):
+        # HTTP/1.1 + a max>1 advertisement lets httrack keep the socket alive
+        protocol_version = "HTTP/1.1"
+
+        def do_GET(self):
+            with open(os.path.join(logdir, ORIGIN_LOG), "a") as handle:
+                handle.write(
+                    "REQUEST %s %s %s\n"
+                    % (self.command, self.path, self.request_version)
+                )
+                for key in self.headers.keys():
+                    handle.write(key + ": " + self.headers[key] + "\n")
+            if "p" in self.path and ".html" in self.path:
+                body = (
+                    b"<html><body>SUBPAGE-563 " + self.path.encode() + b"</body></html>"
+                )
+            else:
+                body = ORIGIN_BODY
+            self.send_response(200)
+            self.send_header("Content-Type", "text/html")
+            self.send_header("Content-Length", str(len(body)))
+            self.send_header("Keep-Alive", "timeout=15, max=100")
+            self.send_header("Connection", "keep-alive")
+            self.end_headers()
+            self.wfile.write(body)
+
+        def log_message(self, *args):
+            pass
+
+    return Origin
+
+
+class ThreadingTCPServer(socketserver.ThreadingTCPServer):
+    allow_reuse_address = True
+    daemon_threads = True
+
+
+def start_origin(logdir, certfile=None):
+    httpd = ThreadingTCPServer(("127.0.0.1", 0), make_origin(logdir))
+    if certfile is not None:
+        ctx = ssl.SSLContext(ssl.PROTOCOL_TLS_SERVER)
+        ctx.load_cert_chain(certfile)
+        httpd.socket = ctx.wrap_socket(httpd.socket, server_side=True)
+    port = httpd.socket.getsockname()[1]
+    threading.Thread(target=httpd.serve_forever, daemon=True).start()
+    return port
+
+
+def recvn(conn, n):
+    buf = b""
+    while len(buf) < n:
+        chunk = conn.recv(n - len(buf))
+        if not chunk:
+            raise OSError("short read")
+        buf += chunk
+    return buf
+
+
+def pipe(src, dst):
+    try:
+        while True:
+            data = src.recv(65536)
+            if not data:
+                break
+            dst.sendall(data)
+    except OSError:
+        pass
+    finally:
+        for sock in (src, dst):
+            try:
+                sock.shutdown(socket.SHUT_RDWR)
+            except OSError:
+                pass
+
+
+def log(logdir, line):
+    with open(os.path.join(logdir, SOCKS_LOG), "a") as handle:
+        handle.write(line + "\n")
+
+
+def negotiate_auth(conn, logdir):
+    """RFC 1928 greeting + RFC 1929 sub-negotiation. Returns True to proceed."""
+    ver, nmethods = recvn(conn, 2)
+    if ver != 0x05:
+        return False
+    methods = recvn(conn, nmethods)
+    if 0x02 in methods:  # prefer user/pass so the auth test exercises RFC 1929
+        conn.sendall(b"\x05\x02")
+        (subver,) = recvn(conn, 1)
+        (ulen,) = recvn(conn, 1)
+        uname = recvn(conn, ulen)
+        (plen,) = recvn(conn, 1)
+        passwd = recvn(conn, plen)
+        log(logdir, "METHOD userpass")
+        log(logdir, "AUTH %s %s" % (uname.decode(), passwd.decode()))
+        conn.sendall(b"\x01\x00")  # RFC 1929 success
+    elif 0x00 in methods:
+        conn.sendall(b"\x05\x00")
+        log(logdir, "METHOD noauth")
+    else:
+        conn.sendall(b"\x05\xff")  # no acceptable method
+        return False
+    return True
+
+
+def read_request(conn, logdir):
+    """RFC 1928 CONNECT. Logs CMD, ATYP, domain/addr, port. Returns dest port."""
+    ver, cmd, _rsv, atyp = recvn(conn, 4)
+    log(logdir, "CMD %d" % cmd)
+    if atyp == 0x01:
+        addr = socket.inet_ntoa(recvn(conn, 4))
+        log(logdir, "ATYP ipv4 %s" % addr)
+    elif atyp == 0x03:
+        (dlen,) = recvn(conn, 1)
+        domain = recvn(conn, dlen)
+        log(logdir, "ATYP domain %s" % domain.decode())
+    elif atyp == 0x04:
+        recvn(conn, 16)
+        log(logdir, "ATYP ipv6")
+        domain = b""
+    else:
+        return None, None
+    (port,) = struct.unpack(">H", recvn(conn, 2))
+    log(logdir, "PORT %d" % port)
+    name = domain if atyp == 0x03 else b""
+    return name, port
+
+
+def reply(conn, rep):
+    conn.sendall(bytes([0x05, rep, 0x00, 0x01]) + b"\x00\x00\x00\x00" + b"\x00\x00")
+
+
+def handle_socks(conn, logdir, mode):
+    try:
+        if not negotiate_auth(conn, logdir):
+            conn.close()
+            return
+        if mode == "truncate":
+            # one byte of the 10-byte reply, then hold the socket: the client
+            # must bound this handshake read and give up, not hang.
+            conn.sendall(b"\x05")
+            threading.Event().wait()
+            return
+        name, port = read_request(conn, logdir)
+        if mode == "refuse" or name != REMOTE_HOST or port is None:
+            reply(conn, 0x05)  # connection refused
+            conn.close()
+            return
+        try:
+            upstream = socket.create_connection(("127.0.0.1", port))
+        except OSError:
+            reply(conn, 0x05)
+            conn.close()
+            return
+        reply(conn, 0x00)  # succeeded
+        threading.Thread(target=pipe, args=(conn, upstream), daemon=True).start()
+        pipe(upstream, conn)
+    except OSError:
+        try:
+            conn.close()
+        except OSError:
+            pass
+
+
+def start_socks(logdir, mode):
+    srv = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+    srv.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+    srv.bind(("127.0.0.1", 0))
+    srv.listen(16)
+    port = srv.getsockname()[1]
+
+    def serve():
+        while True:
+            conn, _ = srv.accept()
+            threading.Thread(
+                target=handle_socks, args=(conn, logdir, mode), daemon=True
+            ).start()
+
+    threading.Thread(target=serve, daemon=True).start()
+    return port
+
+
+def main():
+    certfile, logdir = sys.argv[1], sys.argv[2]
+    mode = sys.argv[3] if len(sys.argv) > 3 else "ok"
+    for name in (SOCKS_LOG, ORIGIN_LOG):
+        open(os.path.join(logdir, name), "w").close()
+    tls_port = start_origin(logdir, certfile)
+    http_port = start_origin(logdir, None)
+    socks_port = start_socks(logdir, mode)
+    print("TLS %d" % tls_port, flush=True)
+    print("HTTP %d" % http_port, flush=True)
+    print("SOCKS %d" % socks_port, flush=True)
+    print("ready", flush=True)
+    threading.Event().wait()
+
+
+if __name__ == "__main__":
+    main()