Make the mode selection clearer.

Line 1003: changed
       to

diagnose_share_key.sh

@@ -48,17 +48,30 @@ usage() {
    fix - these are NOT signature problems, they are Server-Side
    Encryption KEY-MATERIAL problems (a per-user 'share key' for a file
    is either missing on disk or fails to decrypt with that user's
-   private key). This script accepts either a recovery_*.tsv or a
-   restore_*.tsv report as input.
+   private key).
+
+   \033[1mThis script accepts either of two report types as input, and\033[m
+   \033[1mevaluates a different row/status from each:\033[m
+
+         \033[1mrecovery_*.tsv\033[m report  (from recover_bad_signature.sh)
+            ->  evaluates every row whose validation is \033[1mREAD_ERROR\033[m
+
+         \033[1mrestore_*.tsv\033[m  report  (from restore_bad_signature.sh)
+            ->  evaluates every row whose status     is \033[1mWRITE_ERROR\033[m
 
    This script changes NOTHING. It never decrypts a file, never
    touches 'encryption_skip_signature_check', and never writes
    anywhere except its own report file. It only:
 
-      1. Reads a chosen recovery_*.tsv report (produced by
-         recover_bad_signature.sh) and picks out every row whose
-         validation is READ_ERROR and whose detail text matches one of
-         the two known key-material error signatures above.
+      1. Reads the chosen report and picks out the matching rows:
+
+            - from a \033[1mrecovery_*.tsv\033[m report: every row whose
+              validation is \033[1mREAD_ERROR\033[m
+            - from a \033[1mrestore_*.tsv\033[m report: every row whose
+              status is \033[1mWRITE_ERROR\033[m
+
+         ...and, in both cases, whose detail text matches one of the
+         two known key-material error signatures above.
       2. For each such file, resolves - via Nextcloud's normal,
          read-only Files API (\$node->getOwner(), \$folder->getById())
          - who currently owns the file, i.e. whether the affected
@@ -405,8 +418,11 @@ if $terminal ; then
    Nextcloud storage and never touches 'encryption_skip_signature_check'.
    It only inspects, on disk and via the normal Files API, whether the
    expected encryption key files are present for accounts/files that
-   recover_bad_signature.sh could not read (READ_ERROR, not 'Bad
-   Signature').\033[m"
+   recover_bad_signature.sh or restore_bad_signature.sh could not
+   process (not 'Bad Signature').\033[m"
+   echo ""
+   echo -e "   \033[1mrecovery_*.tsv\033[m report  ->  evaluates \033[1mREAD_ERROR\033[m rows"
+   echo -e "   \033[1mrestore_*.tsv\033[m  report  ->  evaluates \033[1mWRITE_ERROR\033[m rows"
    echo -e "\033[32m-----\033[m"
 fi
 
@@ -629,6 +645,13 @@ if ($oldWorkingDir === false) {
 }
 chdir(__DIR__);
 require_once __DIR__ . '/lib/base.php';
+// Nextcloud's own bootstrap (lib/base.php) unconditionally calls
+// set_time_limit(3600) as part of the require above - this OVERRIDES
+// whatever -d max_execution_time was passed on the PHP command line,
+// since it is a later, explicit runtime call. Undo that here, now that
+// the require is done, so diagnosing a large number of files isn't
+// killed after exactly one hour regardless of the CLI flag.
+set_time_limit(0);
 chdir($oldWorkingDir);
 
 if (function_exists('posix_getuid') && posix_getuid() === 0) {
@@ -775,7 +798,11 @@ for _user in "${selected_user_arr[@]}" ; do
    owner_result_tsv="${LOCK_DIR}/owner_${_user}.tsv"
 
    echononl "   Resolving ownership for account \033[1;37m${_user}\033[m (${_user_selected} files).."
-   su -c "$PHP_BIN $diag_php_file $_user $path_list_file" -s /bin/bash $HTTP_USER > "$owner_result_tsv" 2> "$log_file"
+   # -d max_execution_time=0: resolving ownership/key-material for a
+   # large number of files can run well over an hour; without this the
+   # PHP CLI process is killed by PHP's own execution-time limit
+   # (typically inherited from the webserver's php.ini) mid-run.
+   su -c "$PHP_BIN -d max_execution_time=0 $diag_php_file $_user $path_list_file" -s /bin/bash $HTTP_USER > "$owner_result_tsv" 2> "$log_file"
    _rc=$?
 
    if [[ $_rc -ne 0 ]]; then

recover_bad_signature.sh

@@ -148,6 +148,8 @@ restore_encryption_flag() {
 clean_up() {
 
    # Perform program exit housekeeping
+   # Clear EXIT trap first so that the exit below does not fire it again.
+   trap - EXIT
    restore_encryption_flag
    [[ -n "$recovery_php_file" ]] && rm -f "$recovery_php_file" 2> /dev/null
    rm -rf "$LOCK_DIR"
@@ -155,6 +157,82 @@ clean_up() {
    exit $1
 }
 
+
+check_optional_validation_tools() {
+
+   # Checks whether optional tools that improve file-validation quality
+   # are installed.  In interactive mode the user is offered to install
+   # any that are missing via apt.  In non-interactive mode the function
+   # is a quiet no-op (missing tools degrade quality but do not abort).
+
+   local _missing_tools=()
+   local _missing_pkgs=()
+   local _desc=()
+
+   command -v identify > /dev/null 2>&1 || {
+      _missing_tools+=("identify")
+      _missing_pkgs+=("imagemagick")
+      _desc+=("identify  (imagemagick)  — PNG / TIFF / BMP / GIF: vollst. Dekodierung statt nur Magic-Bytes")
+   }
+   command -v ffprobe > /dev/null 2>&1 || {
+      _missing_tools+=("ffprobe")
+      _missing_pkgs+=("ffmpeg")
+      _desc+=("ffprobe   (ffmpeg)       — MP4 / MOV / M4V: Container-Parsing statt nur ftyp-Box-Suche")
+   }
+   command -v mp3val > /dev/null 2>&1 || {
+      _missing_tools+=("mp3val")
+      _missing_pkgs+=("mp3val")
+      _desc+=("mp3val    (mp3val)       — MP3: Frame-Struktur-Check statt nur ID3-Signatur")
+   }
+   command -v flac > /dev/null 2>&1 || {
+      _missing_tools+=("flac")
+      _missing_pkgs+=("flac")
+      _desc+=("flac      (flac)         — FLAC: Decode-Test statt nur fLaC-Signatur")
+   }
+   command -v ogginfo > /dev/null 2>&1 || {
+      _missing_tools+=("ogginfo")
+      _missing_pkgs+=("vorbis-tools")
+      _desc+=("ogginfo   (vorbis-tools) — OGG / OGA / OPUS: Container-Check statt nur OggS-Signatur")
+   }
+
+   [[ ${#_missing_tools[@]} -eq 0 ]] && return 0
+
+   if ! $terminal ; then
+      return 0
+   fi
+
+   local _pkg_list="${_missing_pkgs[*]}"
+
+   echo ""
+   echo -e "   \033[33mOptionale Validierungs-Tools fehlen – Checks laufen mit reduzierter Genauigkeit:\033[m"
+   echo ""
+   local _d
+   for _d in "${_desc[@]}" ; do
+      echo "      ${_d}"
+   done
+   echo ""
+   echo -n "   Jetzt installieren?  apt install ${_pkg_list}  [j/N]: "
+   read -r _yn
+   echo ""
+   if [[ "$_yn" =~ ^[jJyY]$ ]] ; then
+      echononl "   Installiere Pakete: ${_pkg_list}.."
+      # shellcheck disable=SC2086
+      if apt-get install -y ${_missing_pkgs[*]} > /dev/null 2>&1 ; then
+         echo_ok
+      else
+         echo_failed
+         echo ""
+         echo "   Bitte manuell installieren:"
+         echo "      apt install ${_pkg_list}"
+      fi
+   else
+      echo "   Übersprungen — Validierung läuft mit reduzierter Genauigkeit."
+   fi
+   echo ""
+
+}
+
+
 is_number() {
 
    return $(test ! -z "${1##*[!0-9]*}" > /dev/null 2>&1);
@@ -303,37 +381,70 @@ validate_recovered_file() {
          fi
          ;;
       png)
-         local _head
-         _head="$(head -c8 "$_f" 2> /dev/null | od -An -tx1 | tr -d ' \n')"
-         if [[ "$_head" = "89504e470d0a1a0a" ]] ; then
-            echo "VALID|PNG signature ok"
+         if command -v identify > /dev/null 2>&1 ; then
+            # Full decode: catches truncated data, corrupt IDAT chunks, bad CRCs
+            if identify -regard-warnings "$_f" > /dev/null 2>&1 ; then
+               echo "VALID|ImageMagick 'identify' decoded PNG ok"
+            else
+               echo "INVALID|ImageMagick 'identify' failed to decode PNG"
+            fi
          else
-            echo "INVALID|PNG signature missing"
+            local _head
+            _head="$(head -c8 "$_f" 2> /dev/null | od -An -tx1 | tr -d ' \n')"
+            if [[ "$_head" = "89504e470d0a1a0a" ]] ; then
+               echo "VALID|PNG signature ok (identify not installed — no deep check)"
+            else
+               echo "INVALID|PNG signature missing"
+            fi
          fi
          ;;
       gif)
-         local _head6
-         _head6="$(head -c6 "$_f" 2> /dev/null)"
-         if [[ "$_head6" = "GIF87a" || "$_head6" = "GIF89a" ]] ; then
-            echo "VALID|GIF signature ok"
+         if command -v identify > /dev/null 2>&1 ; then
+            if identify -regard-warnings "$_f" > /dev/null 2>&1 ; then
+               echo "VALID|ImageMagick 'identify' decoded GIF ok"
+            else
+               echo "INVALID|ImageMagick 'identify' failed to decode GIF"
+            fi
          else
-            echo "INVALID|GIF signature missing"
+            local _head6
+            _head6="$(head -c6 "$_f" 2> /dev/null)"
+            if [[ "$_head6" = "GIF87a" || "$_head6" = "GIF89a" ]] ; then
+               echo "VALID|GIF signature ok (identify not installed — no deep check)"
+            else
+               echo "INVALID|GIF signature missing"
+            fi
          fi
          ;;
       bmp)
-         if [[ "$(head -c2 "$_f" 2> /dev/null)" = "BM" ]] ; then
-            echo "VALID|BMP signature ok"
+         if command -v identify > /dev/null 2>&1 ; then
+            if identify -regard-warnings "$_f" > /dev/null 2>&1 ; then
+               echo "VALID|ImageMagick 'identify' decoded BMP ok"
+            else
+               echo "INVALID|ImageMagick 'identify' failed to decode BMP"
+            fi
          else
-            echo "INVALID|BMP signature missing"
+            if [[ "$(head -c2 "$_f" 2> /dev/null)" = "BM" ]] ; then
+               echo "VALID|BMP signature ok (identify not installed — no deep check)"
+            else
+               echo "INVALID|BMP signature missing"
+            fi
          fi
          ;;
       tif|tiff)
-         local _head4
-         _head4="$(head -c4 "$_f" 2> /dev/null | od -An -tx1 | tr -d ' \n')"
-         if [[ "$_head4" = "49492a00" || "$_head4" = "4d4d002a" ]] ; then
-            echo "VALID|TIFF signature ok"
+         if command -v identify > /dev/null 2>&1 ; then
+            if identify -regard-warnings "$_f" > /dev/null 2>&1 ; then
+               echo "VALID|ImageMagick 'identify' decoded TIFF ok"
+            else
+               echo "INVALID|ImageMagick 'identify' failed to decode TIFF"
+            fi
          else
-            echo "INVALID|TIFF signature missing"
+            local _head4
+            _head4="$(head -c4 "$_f" 2> /dev/null | od -An -tx1 | tr -d ' \n')"
+            if [[ "$_head4" = "49492a00" || "$_head4" = "4d4d002a" ]] ; then
+               echo "VALID|TIFF signature ok (identify not installed — no deep check)"
+            else
+               echo "INVALID|TIFF signature missing"
+            fi
          fi
          ;;
       pnm|pgm|ppm|pbm)
@@ -360,22 +471,58 @@ validate_recovered_file() {
          if [[ "$_head8o" = "d0cf11e0a1b11ae1" ]] ; then
             echo "VALID|OLE2/CFBF container signature ok - this is a password-protected Office file (encrypted package), not a plain zip, so the zip check does not apply; open it with the password to verify content"
          elif command -v unzip > /dev/null 2>&1 ; then
-            if unzip -tq "$_f" > /dev/null 2>&1 ; then
+            # Run unzip inside setsid so it has no controlling terminal.
+            # Without setsid, a password-protected ZIP causes unzip to try
+            # opening /dev/tty to prompt for the password. When running in
+            # the background of a tmux session this generates SIGTTIN, which
+            # STOPS the process (ps state T). A stopped process cannot receive
+            # SIGTERM, so timeout hangs indefinitely waiting for a child that
+            # will never exit. With setsid the /dev/tty open fails immediately
+            # with ENXIO and unzip exits with a non-zero code instead.
+            # -k 5: send SIGKILL 5 s after SIGTERM in case the process is
+            # still alive (e.g. stopped or in uninterruptible sleep).
+            local _unzip_exit
+            timeout -k 5 120 setsid unzip -tq "$_f" < /dev/null > /dev/null 2>&1
+            _unzip_exit=$?
+            if [[ $_unzip_exit -eq 0 ]] ; then
                echo "VALID|zip integrity ok"
+            elif [[ $_unzip_exit -eq 124 || $_unzip_exit -eq 137 ]] ; then
+               # 124 = killed by SIGTERM after timeout, 137 = killed by SIGKILL (128+9)
+               echo "UNVERIFIED|zip integrity check timed out after 120 s (file may be very large or corrupt; check manually with: unzip -t \"$_f\")"
             else
                local _badentry
-               _badentry="$(trim "$(unzip -t "$_f" 2>&1 | grep -v '^Archive:' | grep -v '^[[:space:]]*$' | head -1)")"
-               echo "INVALID|zip integrity check failed${_badentry:+ (${_badentry})}"
+               _badentry="$(trim "$(timeout -k 5 120 setsid unzip -t "$_f" < /dev/null 2>&1 | grep -v '^Archive:' | grep -v '^[[:space:]]*$' | head -1)")"
+               if echo "$_badentry" | grep -qi "password\|encrypt\|need PK compat" ; then
+                  echo "UNVERIFIED|zip is password-protected (cannot verify without password${_badentry:+; unzip says: ${_badentry}})"
+               else
+                  echo "INVALID|zip integrity check failed${_badentry:+ (${_badentry})}"
+               fi
             fi
          else
             echo "UNVERIFIED|unzip not installed"
          fi
          ;;
       mp4|mov|m4v)
-         if head -c 64 "$_f" 2> /dev/null | grep -aq "ftyp" ; then
-            echo "VALID|mp4 ftyp box found"
+         if command -v ffprobe > /dev/null 2>&1 ; then
+            # Full container parse: detects truncated/corrupt streams
+            local _ffprobe_out _ffprobe_exit
+            _ffprobe_out="$(ffprobe -v error -show_streams "$_f" 2>&1)"
+            _ffprobe_exit=$?
+            if [[ $_ffprobe_exit -eq 0 ]] ; then
+               local _streams
+               _streams="$(echo "$_ffprobe_out" | grep -c '\[STREAM\]' || true)"
+               echo "VALID|ffprobe parsed container ok (${_streams} stream(s) found)"
+            else
+               local _ffprobe_err
+               _ffprobe_err="$(echo "$_ffprobe_out" | head -1)"
+               echo "INVALID|ffprobe failed to parse container${_ffprobe_err:+ (${_ffprobe_err})}"
+            fi
          else
-            echo "INVALID|mp4 ftyp box not found"
+            if head -c 64 "$_f" 2> /dev/null | grep -aq "ftyp" ; then
+               echo "VALID|mp4 ftyp box found (ffprobe not installed — no deep check)"
+            else
+               echo "INVALID|mp4 ftyp box not found"
+            fi
          fi
          ;;
       doc|xls|ppt|ole|msi)
@@ -475,6 +622,75 @@ validate_recovered_file() {
             echo "INVALID|GIMP (gimp xcf) signature missing"
          fi
          ;;
+      mp3)
+         if command -v mp3val > /dev/null 2>&1 ; then
+            # mp3val always exits 0 but prints "No errors found" on success
+            local _mp3val_out
+            _mp3val_out="$(mp3val "$_f" 2>&1)"
+            if echo "$_mp3val_out" | grep -q 'No errors found' ; then
+               echo "VALID|mp3val: no errors found"
+            else
+               local _mp3_err
+               _mp3_err="$(echo "$_mp3val_out" | grep -iv '^mp3val\|^$' | head -2 | tr '\n' ' ' | sed 's/ $//')"
+               echo "INVALID|mp3val reported errors${_mp3_err:+ (${_mp3_err})}"
+            fi
+         else
+            local _head3 _head2hex
+            _head3="$(head -c3 "$_f" 2>/dev/null)"
+            _head2hex="$(head -c2 "$_f" 2>/dev/null | od -An -tx1 | tr -d ' \n')"
+            if [[ "$_head3" = "ID3" ]] || echo "$_head2hex" | grep -qE '^fff[bef2]' ; then
+               echo "VALID|MP3 ID3 tag / MPEG sync ok (mp3val not installed — no deep check)"
+            else
+               echo "INVALID|MP3: no ID3 header or MPEG frame sync found"
+            fi
+         fi
+         ;;
+      flac)
+         if command -v flac > /dev/null 2>&1 ; then
+            # --test decodes without writing output; exit 0 = file is intact
+            local _flac_out _flac_exit
+            _flac_out="$(flac --silent --test "$_f" 2>&1)"
+            _flac_exit=$?
+            if [[ $_flac_exit -eq 0 ]] ; then
+               echo "VALID|flac --test: ok"
+            else
+               local _flac_err
+               _flac_err="$(echo "$_flac_out" | grep -v '^$' | tail -1)"
+               echo "INVALID|flac --test failed${_flac_err:+ (${_flac_err})}"
+            fi
+         else
+            local _head4hex
+            _head4hex="$(head -c4 "$_f" 2>/dev/null | od -An -tx1 | tr -d ' \n')"
+            if [[ "$_head4hex" = "664c6143" ]] ; then  # "fLaC"
+               echo "VALID|FLAC 'fLaC' signature ok (flac not installed — no deep check)"
+            else
+               echo "INVALID|FLAC 'fLaC' signature missing"
+            fi
+         fi
+         ;;
+      ogg|oga|ogv|opus)
+         if command -v ogginfo > /dev/null 2>&1 ; then
+            # ogginfo exits 0 if the Ogg container is intact
+            local _ogg_out _ogg_exit
+            _ogg_out="$(ogginfo "$_f" 2>&1)"
+            _ogg_exit=$?
+            if [[ $_ogg_exit -eq 0 ]] ; then
+               echo "VALID|ogginfo: container parsed ok"
+            else
+               local _ogg_err
+               _ogg_err="$(echo "$_ogg_out" | grep -iv '^Processing\|^$' | head -2 | tr '\n' ' ' | sed 's/ $//')"
+               echo "INVALID|ogginfo failed${_ogg_err:+ (${_ogg_err})}"
+            fi
+         else
+            local _head4ogg
+            _head4ogg="$(head -c4 "$_f" 2>/dev/null)"
+            if [[ "$_head4ogg" = "OggS" ]] ; then
+               echo "VALID|OGG 'OggS' signature ok (ogginfo not installed — no deep check)"
+            else
+               echo "INVALID|OGG 'OggS' signature missing"
+            fi
+         fi
+         ;;
       wav)
          local _riff _wave
          _riff="$(head -c4 "$_f" 2> /dev/null)"
@@ -562,6 +778,15 @@ validate_recovered_file() {
 ## - PDF structural check shared by the 'pdf' case and the 'ai'
 ## - (PDF-compatible) case. Sets $_pdf_check_detail, returns 0/1.
 ## -
+## - qpdf exit codes:
+## -   0  no problems
+## -   2  structural errors   → file is genuinely corrupt/unreadable
+## -   3  warnings only       → minor spec non-conformances; every real
+## -                            viewer opens the file without issues
+## - Only exit code 2 is treated as INVALID here.  Exit code 3 (warnings)
+## - is reported as VALID with a note, preventing false positives for
+## - real-world PDFs that have trivial non-conformances.
+## -
 _pdf_check() {
    local _f="$1"
    if [[ "$(head -c5 "$_f" 2> /dev/null)" != "%PDF-" ]] ; then
@@ -569,11 +794,22 @@ _pdf_check() {
       return 1
    fi
    if command -v qpdf > /dev/null 2>&1 ; then
-      if qpdf --check "$_f" > /dev/null 2>&1 ; then
+      local _qpdf_out _qpdf_exit
+      _qpdf_out="$(qpdf --check "$_f" 2>&1)"
+      _qpdf_exit=$?
+      if [[ $_qpdf_exit -eq 0 ]] ; then
          _pdf_check_detail="qpdf --check ok"
          return 0
+      elif [[ $_qpdf_exit -eq 3 ]] ; then
+         # Warnings only — no structural errors.  File is readable by all
+         # standard PDF viewers; non-conformances are minor/cosmetic.
+         _pdf_check_detail="qpdf --check ok (warnings only — file is readable)"
+         return 0
       else
-         _pdf_check_detail="qpdf --check failed"
+         # Exit code 2 (or unexpected): genuine structural errors.
+         local _first_err
+         _first_err="$(echo "$_qpdf_out" | grep -i 'error' | head -1 | sed 's/^[[:space:]]*//')"
+         _pdf_check_detail="qpdf --check failed (exit ${_qpdf_exit}${_first_err:+: ${_first_err}})"
          return 1
       fi
    fi
@@ -764,7 +1000,7 @@ if mkdir "$LOCK_DIR" 2> /dev/null ; then
 
    # - Remove lockdir when the script finishes, or when it receives a signal
    # -
-   trap clean_up SIGHUP SIGINT SIGTERM
+   trap 'clean_up 1' SIGHUP SIGINT SIGTERM
 
 else
 
@@ -814,12 +1050,13 @@ if ! $_revalidate_only_explicit && $terminal ; then
    echo -e "\033[37m\033[1mWhich mode should this run use?\033[m"
    echo ""
    echo -e "   \033[1m[1] Recovery\033[m         - decrypt bad-signature files (temporarily skips the signature check),
-                          write them under \033[1m${DEFAULT_RECOVERY_BASE_DIR}/<website>\033[m and validate them"
+                          write them under 
+                             \033[1m${DEFAULT_RECOVERY_BASE_DIR}/<website>\033[m
+                          and validate them"
    echo ""
    echo    "   [2] Revalidate-only  - re-run just the validation checks against files a previous recovery run 
-                          already wrote to disk (same as '-V'); nothing is decrypted again and no config 
-                          value is touched"
-
+                          already wrote to disk (same as '-V'); nothing is decrypted again and 
+                          no config value is touched"
    info "Just press Return to use the default: [1] Recovery."
    echo -n "   Select mode by number [1]: "
    read _mode_choice
@@ -1082,6 +1319,8 @@ done
 mkdir -p "$report_dir" 2> /dev/null
 recovery_report_file="${report_dir}/recovery_${WEBSITE}_${run_date}.tsv"
 
+check_optional_validation_tools
+
 if $terminal ; then
    echo ""
    if $REVALIDATE_ONLY ; then
@@ -1122,6 +1361,18 @@ if $terminal ; then
    fi
 fi
 
+if $terminal ; then
+   echo ""
+   echo -e "   \033[1mTemporäre Dateien – werden laufend aktualisiert:\033[m"
+   echo ""
+   echo -e "   Fortschritt / Debug-Meldungen (PHP-Ausgabe auf STDERR):"
+   echo -e "      \033[1mtail -f ${log_file}\033[m"
+   echo ""
+   echo -e "   Rohergebnis pro Account (PHP-Ausgabe auf STDOUT, Datei für Datei):"
+   echo -e "      \033[1mtail -f ${LOCK_DIR}/result_<account>.tsv\033[m"
+   echo ""
+fi
+
 
 {
    echo "=================================================================="
@@ -1152,7 +1403,10 @@ su -c "$PHP_BIN $INSTALL_DIR/occ config:system:set encryption_skip_signature_che
 if [[ $? -eq 0 ]] ; then
    echo_ok
    _encryption_flag_changed=true
-   trap 'restore_encryption_flag; clean_up 1' SIGHUP SIGINT SIGTERM
+   # Trap signals AND normal/abnormal exit so that the encryption flag
+   # and temp files are always cleaned up — even on a syntax error or
+   # an unexpected crash (EXIT fires for any bash exit, including errors).
+   trap 'clean_up 1' SIGHUP SIGINT SIGTERM EXIT
 else
    echo_failed
    fatal "Could not enable encryption_skip_signature_check: $(cat "$log_file")"
@@ -1204,6 +1458,13 @@ if ($oldWorkingDir === false) {
 }
 chdir(__DIR__);
 require_once __DIR__ . '/lib/base.php';
+// Nextcloud's own bootstrap (lib/base.php) unconditionally calls
+// set_time_limit(3600) as part of the require above - this OVERRIDES
+// whatever -d max_execution_time was passed on the PHP command line,
+// since it is a later, explicit runtime call. Undo that here, now that
+// the require is done, so recovering a large account isn't killed
+// after exactly one hour regardless of the CLI flag.
+set_time_limit(0);
 chdir($oldWorkingDir);
 
 if (function_exists('posix_getuid') && posix_getuid() === 0) {
@@ -1438,7 +1699,11 @@ for _user in "${selected_user_arr[@]}" ; do
       chown -R "$HTTP_USER":"$HTTP_GROUP" "$recovery_dir" 2> /dev/null
 
       echononl "   Recovering account \033[1;37m${_user}\033[m (${_user_total} files).."
-      su -c "$PHP_BIN $recovery_php_file $_user $list_file $user_out_dir" -s /bin/bash $HTTP_USER > "$user_result_tsv" 2> "$log_file"
+      # -d max_execution_time=0: decrypting/validating every file of a
+      # large account can run well over an hour; without this the PHP
+      # CLI process is killed by PHP's own execution-time limit
+      # (typically inherited from the webserver's php.ini) mid-run.
+      su -c "$PHP_BIN -d max_execution_time=0 $recovery_php_file $_user $list_file $user_out_dir" -s /bin/bash $HTTP_USER > "$user_result_tsv" 2> "$log_file"
       _rc=$?
 
    fi

recreate_bad_signature.sh

@@ -183,6 +183,8 @@ usage() {
 clean_up() {
 
    # Perform program exit housekeeping
+   # Clear EXIT trap first so that the exit below does not fire it again.
+   trap - EXIT
    [[ -n "$recreate_php_file" ]] && rm -f "$recreate_php_file" 2> /dev/null
    rm -rf "$LOCK_DIR"
    blank_line
@@ -190,6 +192,77 @@ clean_up() {
 
 }
 
+
+check_optional_validation_tools() {
+
+   local _missing_tools=()
+   local _missing_pkgs=()
+   local _desc=()
+
+   command -v identify > /dev/null 2>&1 || {
+      _missing_tools+=("identify")
+      _missing_pkgs+=("imagemagick")
+      _desc+=("identify  (imagemagick)  — PNG / TIFF / BMP / GIF: vollst. Dekodierung statt nur Magic-Bytes")
+   }
+   command -v ffprobe > /dev/null 2>&1 || {
+      _missing_tools+=("ffprobe")
+      _missing_pkgs+=("ffmpeg")
+      _desc+=("ffprobe   (ffmpeg)       — MP4 / MOV / M4V: Container-Parsing statt nur ftyp-Box-Suche")
+   }
+   command -v mp3val > /dev/null 2>&1 || {
+      _missing_tools+=("mp3val")
+      _missing_pkgs+=("mp3val")
+      _desc+=("mp3val    (mp3val)       — MP3: Frame-Struktur-Check statt nur ID3-Signatur")
+   }
+   command -v flac > /dev/null 2>&1 || {
+      _missing_tools+=("flac")
+      _missing_pkgs+=("flac")
+      _desc+=("flac      (flac)         — FLAC: Decode-Test statt nur fLaC-Signatur")
+   }
+   command -v ogginfo > /dev/null 2>&1 || {
+      _missing_tools+=("ogginfo")
+      _missing_pkgs+=("vorbis-tools")
+      _desc+=("ogginfo   (vorbis-tools) — OGG / OGA / OPUS: Container-Check statt nur OggS-Signatur")
+   }
+
+   [[ ${#_missing_tools[@]} -eq 0 ]] && return 0
+
+   if ! $terminal ; then
+      return 0
+   fi
+
+   local _pkg_list="${_missing_pkgs[*]}"
+
+   echo ""
+   echo -e "   \033[33mOptionale Validierungs-Tools fehlen – Checks laufen mit reduzierter Genauigkeit:\033[m"
+   echo ""
+   local _d
+   for _d in "${_desc[@]}" ; do
+      echo "      ${_d}"
+   done
+   echo ""
+   echo -n "   Jetzt installieren?  apt install ${_pkg_list}  [j/N]: "
+   read -r _yn
+   echo ""
+   if [[ "$_yn" =~ ^[jJyY]$ ]] ; then
+      echononl "   Installiere Pakete: ${_pkg_list}.."
+      # shellcheck disable=SC2086
+      if apt-get install -y ${_missing_pkgs[*]} > /dev/null 2>&1 ; then
+         echo_ok
+      else
+         echo_failed
+         echo ""
+         echo "   Bitte manuell installieren:"
+         echo "      apt install ${_pkg_list}"
+      fi
+   else
+      echo "   Übersprungen — Validierung läuft mit reduzierter Genauigkeit."
+   fi
+   echo ""
+
+}
+
+
 is_number() {
 
    return $(test ! -z "${1##*[!0-9]*}" > /dev/null 2>&1);
@@ -338,37 +411,69 @@ validate_recovered_file() {
          fi
          ;;
       png)
-         local _head
-         _head="$(head -c8 "$_f" 2> /dev/null | od -An -tx1 | tr -d ' \n')"
-         if [[ "$_head" = "89504e470d0a1a0a" ]] ; then
-            echo "VALID|PNG signature ok"
+         if command -v identify > /dev/null 2>&1 ; then
+            if identify -regard-warnings "$_f" > /dev/null 2>&1 ; then
+               echo "VALID|ImageMagick 'identify' decoded PNG ok"
+            else
+               echo "INVALID|ImageMagick 'identify' failed to decode PNG"
+            fi
          else
-            echo "INVALID|PNG signature missing"
+            local _head
+            _head="$(head -c8 "$_f" 2> /dev/null | od -An -tx1 | tr -d ' \n')"
+            if [[ "$_head" = "89504e470d0a1a0a" ]] ; then
+               echo "VALID|PNG signature ok (identify not installed — no deep check)"
+            else
+               echo "INVALID|PNG signature missing"
+            fi
          fi
          ;;
       gif)
-         local _head6
-         _head6="$(head -c6 "$_f" 2> /dev/null)"
-         if [[ "$_head6" = "GIF87a" || "$_head6" = "GIF89a" ]] ; then
-            echo "VALID|GIF signature ok"
+         if command -v identify > /dev/null 2>&1 ; then
+            if identify -regard-warnings "$_f" > /dev/null 2>&1 ; then
+               echo "VALID|ImageMagick 'identify' decoded GIF ok"
+            else
+               echo "INVALID|ImageMagick 'identify' failed to decode GIF"
+            fi
          else
-            echo "INVALID|GIF signature missing"
+            local _head6
+            _head6="$(head -c6 "$_f" 2> /dev/null)"
+            if [[ "$_head6" = "GIF87a" || "$_head6" = "GIF89a" ]] ; then
+               echo "VALID|GIF signature ok (identify not installed — no deep check)"
+            else
+               echo "INVALID|GIF signature missing"
+            fi
          fi
          ;;
       bmp)
-         if [[ "$(head -c2 "$_f" 2> /dev/null)" = "BM" ]] ; then
-            echo "VALID|BMP signature ok"
+         if command -v identify > /dev/null 2>&1 ; then
+            if identify -regard-warnings "$_f" > /dev/null 2>&1 ; then
+               echo "VALID|ImageMagick 'identify' decoded BMP ok"
+            else
+               echo "INVALID|ImageMagick 'identify' failed to decode BMP"
+            fi
          else
-            echo "INVALID|BMP signature missing"
+            if [[ "$(head -c2 "$_f" 2> /dev/null)" = "BM" ]] ; then
+               echo "VALID|BMP signature ok (identify not installed — no deep check)"
+            else
+               echo "INVALID|BMP signature missing"
+            fi
          fi
          ;;
       tif|tiff)
-         local _head4
-         _head4="$(head -c4 "$_f" 2> /dev/null | od -An -tx1 | tr -d ' \n')"
-         if [[ "$_head4" = "49492a00" || "$_head4" = "4d4d002a" ]] ; then
-            echo "VALID|TIFF signature ok"
+         if command -v identify > /dev/null 2>&1 ; then
+            if identify -regard-warnings "$_f" > /dev/null 2>&1 ; then
+               echo "VALID|ImageMagick 'identify' decoded TIFF ok"
+            else
+               echo "INVALID|ImageMagick 'identify' failed to decode TIFF"
+            fi
          else
-            echo "INVALID|TIFF signature missing"
+            local _head4
+            _head4="$(head -c4 "$_f" 2> /dev/null | od -An -tx1 | tr -d ' \n')"
+            if [[ "$_head4" = "49492a00" || "$_head4" = "4d4d002a" ]] ; then
+               echo "VALID|TIFF signature ok (identify not installed — no deep check)"
+            else
+               echo "INVALID|TIFF signature missing"
+            fi
          fi
          ;;
       pnm|pgm|ppm|pbm)
@@ -386,22 +491,57 @@ validate_recovered_file() {
          if [[ "$_head8o" = "d0cf11e0a1b11ae1" ]] ; then
             echo "VALID|OLE2/CFBF container signature ok - this is a password-protected Office file (encrypted package), not a plain zip, so the zip check does not apply; open it with the password to verify content"
          elif command -v unzip > /dev/null 2>&1 ; then
-            if unzip -tq "$_f" > /dev/null 2>&1 ; then
+            # Run unzip inside setsid so it has no controlling terminal.
+            # Without setsid, a password-protected ZIP causes unzip to try
+            # opening /dev/tty to prompt for the password. When running in
+            # the background of a tmux session this generates SIGTTIN, which
+            # STOPS the process (ps state T). A stopped process cannot receive
+            # SIGTERM, so timeout hangs indefinitely waiting for a child that
+            # will never exit. With setsid the /dev/tty open fails immediately
+            # with ENXIO and unzip exits with a non-zero code instead.
+            # -k 5: send SIGKILL 5 s after SIGTERM in case the process is
+            # still alive (e.g. stopped or in uninterruptible sleep).
+            local _unzip_exit
+            timeout -k 5 120 setsid unzip -tq "$_f" < /dev/null > /dev/null 2>&1
+            _unzip_exit=$?
+            if [[ $_unzip_exit -eq 0 ]] ; then
                echo "VALID|zip integrity ok"
+            elif [[ $_unzip_exit -eq 124 || $_unzip_exit -eq 137 ]] ; then
+               # 124 = killed by SIGTERM after timeout, 137 = killed by SIGKILL (128+9)
+               echo "UNVERIFIED|zip integrity check timed out after 120 s (file may be very large or corrupt; check manually with: unzip -t \"$_f\")"
             else
                local _badentry
-               _badentry="$(trim "$(unzip -t "$_f" 2>&1 | grep -v '^Archive:' | grep -v '^[[:space:]]*$' | head -1)")"
-               echo "INVALID|zip integrity check failed${_badentry:+ (${_badentry})}"
+               _badentry="$(trim "$(timeout -k 5 120 setsid unzip -t "$_f" < /dev/null 2>&1 | grep -v '^Archive:' | grep -v '^[[:space:]]*$' | head -1)")"
+               if echo "$_badentry" | grep -qi "password\|encrypt\|need PK compat" ; then
+                  echo "UNVERIFIED|zip is password-protected (cannot verify without password${_badentry:+; unzip says: ${_badentry}})"
+               else
+                  echo "INVALID|zip integrity check failed${_badentry:+ (${_badentry})}"
+               fi
             fi
          else
             echo "UNVERIFIED|unzip not installed"
          fi
          ;;
       mp4|mov|m4v)
-         if head -c 64 "$_f" 2> /dev/null | grep -aq "ftyp" ; then
-            echo "VALID|mp4 ftyp box found"
+         if command -v ffprobe > /dev/null 2>&1 ; then
+            local _ffprobe_out _ffprobe_exit
+            _ffprobe_out="$(ffprobe -v error -show_streams "$_f" 2>&1)"
+            _ffprobe_exit=$?
+            if [[ $_ffprobe_exit -eq 0 ]] ; then
+               local _streams
+               _streams="$(echo "$_ffprobe_out" | grep -c '\[STREAM\]' || true)"
+               echo "VALID|ffprobe parsed container ok (${_streams} stream(s) found)"
+            else
+               local _ffprobe_err
+               _ffprobe_err="$(echo "$_ffprobe_out" | head -1)"
+               echo "INVALID|ffprobe failed to parse container${_ffprobe_err:+ (${_ffprobe_err})}"
+            fi
          else
-            echo "INVALID|mp4 ftyp box not found"
+            if head -c 64 "$_f" 2> /dev/null | grep -aq "ftyp" ; then
+               echo "VALID|mp4 ftyp box found (ffprobe not installed — no deep check)"
+            else
+               echo "INVALID|mp4 ftyp box not found"
+            fi
          fi
          ;;
       doc|xls|ppt|ole|msi)
@@ -493,6 +633,72 @@ validate_recovered_file() {
             echo "INVALID|GIMP (gimp xcf) signature missing"
          fi
          ;;
+      mp3)
+         if command -v mp3val > /dev/null 2>&1 ; then
+            local _mp3val_out
+            _mp3val_out="$(mp3val "$_f" 2>&1)"
+            if echo "$_mp3val_out" | grep -q 'No errors found' ; then
+               echo "VALID|mp3val: no errors found"
+            else
+               local _mp3_err
+               _mp3_err="$(echo "$_mp3val_out" | grep -iv '^mp3val\|^$' | head -2 | tr '\n' ' ' | sed 's/ $//')"
+               echo "INVALID|mp3val reported errors${_mp3_err:+ (${_mp3_err})}"
+            fi
+         else
+            local _head3 _head2hex
+            _head3="$(head -c3 "$_f" 2>/dev/null)"
+            _head2hex="$(head -c2 "$_f" 2>/dev/null | od -An -tx1 | tr -d ' \n')"
+            if [[ "$_head3" = "ID3" ]] || echo "$_head2hex" | grep -qE '^fff[bef2]' ; then
+               echo "VALID|MP3 ID3 tag / MPEG sync ok (mp3val not installed — no deep check)"
+            else
+               echo "INVALID|MP3: no ID3 header or MPEG frame sync found"
+            fi
+         fi
+         ;;
+      flac)
+         if command -v flac > /dev/null 2>&1 ; then
+            local _flac_out _flac_exit
+            _flac_out="$(flac --silent --test "$_f" 2>&1)"
+            _flac_exit=$?
+            if [[ $_flac_exit -eq 0 ]] ; then
+               echo "VALID|flac --test: ok"
+            else
+               local _flac_err
+               _flac_err="$(echo "$_flac_out" | grep -v '^$' | tail -1)"
+               echo "INVALID|flac --test failed${_flac_err:+ (${_flac_err})}"
+            fi
+         else
+            local _head4hex
+            _head4hex="$(head -c4 "$_f" 2>/dev/null | od -An -tx1 | tr -d ' \n')"
+            if [[ "$_head4hex" = "664c6143" ]] ; then
+               echo "VALID|FLAC 'fLaC' signature ok (flac not installed — no deep check)"
+            else
+               echo "INVALID|FLAC 'fLaC' signature missing"
+            fi
+         fi
+         ;;
+      ogg|oga|ogv|opus)
+         if command -v ogginfo > /dev/null 2>&1 ; then
+            local _ogg_out _ogg_exit
+            _ogg_out="$(ogginfo "$_f" 2>&1)"
+            _ogg_exit=$?
+            if [[ $_ogg_exit -eq 0 ]] ; then
+               echo "VALID|ogginfo: container parsed ok"
+            else
+               local _ogg_err
+               _ogg_err="$(echo "$_ogg_out" | grep -iv '^Processing\|^$' | head -2 | tr '\n' ' ' | sed 's/ $//')"
+               echo "INVALID|ogginfo failed${_ogg_err:+ (${_ogg_err})}"
+            fi
+         else
+            local _head4ogg
+            _head4ogg="$(head -c4 "$_f" 2>/dev/null)"
+            if [[ "$_head4ogg" = "OggS" ]] ; then
+               echo "VALID|OGG 'OggS' signature ok (ogginfo not installed — no deep check)"
+            else
+               echo "INVALID|OGG 'OggS' signature missing"
+            fi
+         fi
+         ;;
       wav)
          local _riff _wave
          _riff="$(head -c4 "$_f" 2> /dev/null)"
@@ -564,6 +770,15 @@ validate_recovered_file() {
    esac
 }
 
+## - qpdf exit codes:
+## -   0  no problems
+## -   2  structural errors   → file is genuinely corrupt/unreadable
+## -   3  warnings only       → minor spec non-conformances; every real
+## -                            viewer opens the file without issues
+## - Only exit code 2 is treated as INVALID here.  Exit code 3 (warnings)
+## - is reported as VALID with a note, preventing false positives for
+## - real-world PDFs that have trivial non-conformances.
+## -
 _pdf_check() {
    local _f="$1"
    if [[ "$(head -c5 "$_f" 2> /dev/null)" != "%PDF-" ]] ; then
@@ -571,11 +786,22 @@ _pdf_check() {
       return 1
    fi
    if command -v qpdf > /dev/null 2>&1 ; then
-      if qpdf --check "$_f" > /dev/null 2>&1 ; then
+      local _qpdf_out _qpdf_exit
+      _qpdf_out="$(qpdf --check "$_f" 2>&1)"
+      _qpdf_exit=$?
+      if [[ $_qpdf_exit -eq 0 ]] ; then
          _pdf_check_detail="qpdf --check ok"
          return 0
+      elif [[ $_qpdf_exit -eq 3 ]] ; then
+         # Warnings only — no structural errors.  File is readable by all
+         # standard PDF viewers; non-conformances are minor/cosmetic.
+         _pdf_check_detail="qpdf --check ok (warnings only — file is readable)"
+         return 0
       else
-         _pdf_check_detail="qpdf --check failed"
+         # Exit code 2 (or unexpected): genuine structural errors.
+         local _first_err
+         _first_err="$(echo "$_qpdf_out" | grep -i 'error' | head -1 | sed 's/^[[:space:]]*//')"
+         _pdf_check_detail="qpdf --check failed (exit ${_qpdf_exit}${_first_err:+: ${_first_err}})"
          return 1
       fi
    fi
@@ -731,7 +957,9 @@ fi
 # -
 if mkdir "$LOCK_DIR" 2> /dev/null ; then
 
-   trap clean_up SIGHUP SIGINT SIGTERM
+   # Trap signals AND normal/abnormal exit so that temp files and the
+   # lock directory are always removed — even on an unexpected crash.
+   trap 'clean_up 1' SIGHUP SIGINT SIGTERM EXIT
 
 else
 
@@ -785,9 +1013,8 @@ if ! $_dry_run_explicit && $terminal ; then
    echo -e "   \033[1m[1] Dry-run\033[m          - go through everything (selection, re-validation, share check,
                           reporting), but delete, back up, create or verify NOTHING"
    echo ""
-   echo    "   [2] Real recreate   - actually back up, DELETE the broken file, create it fresh 
-                         and verify each one"
-
+   echo    "   [2] Real recreate    - actually back up, DELETE the broken file, create it fresh 
+                          and verify each one"
    info "Just press Return to use the default: [1] Dry-run."
    echo -n "   Select mode by number [1]: "
    read _mode_choice
@@ -1041,6 +1268,8 @@ done
 mkdir -p "$report_dir" 2> /dev/null
 recreate_report_file="${report_dir}/recreate_${WEBSITE}_${run_date}.tsv"
 
+check_optional_validation_tools
+
 if $terminal ; then
    echo ""
    if $DRY_RUN ; then
@@ -1084,6 +1313,18 @@ if $terminal ; then
    fi
 fi
 
+if $terminal ; then
+   echo ""
+   echo -e "   \033[1mTemporäre Dateien – werden laufend aktualisiert:\033[m"
+   echo ""
+   echo -e "   Fortschritt / Debug-Meldungen (PHP-Ausgabe auf STDERR, pro Account):"
+   echo -e "      \033[1mtail -f ${LOCK_DIR}/${script_name%%.*}_<account>.log\033[m"
+   echo ""
+   echo -e "   Rohergebnis pro Account (PHP-Ausgabe auf STDOUT, Datei für Datei):"
+   echo -e "      \033[1mtail -f ${LOCK_DIR}/result_<account>.tsv\033[m"
+   echo ""
+fi
+
 
 {
    echo "=================================================================="
@@ -1166,6 +1407,13 @@ if ($oldWorkingDir === false) {
 }
 chdir(__DIR__);
 require_once __DIR__ . '/lib/base.php';
+// Nextcloud's own bootstrap (lib/base.php) unconditionally calls
+// set_time_limit(3600) as part of the require above - this OVERRIDES
+// whatever -d max_execution_time was passed on the PHP command line,
+// since it is a later, explicit runtime call. Undo that here, now that
+// the require is done, so recreating a large account isn't killed
+// after exactly one hour regardless of the CLI flag.
+set_time_limit(0);
 chdir($oldWorkingDir);
 
 if (function_exists('posix_getuid') && posix_getuid() === 0) {
@@ -1767,7 +2015,11 @@ for _user in "${selected_user_arr[@]}" ; do
       _php_args=("$recreate_php_file" "$_user" "$list_file" "$DATA_DIR")
       $DRY_RUN && _php_args+=("--dry-run")
       $FORCE_SHARED && _php_args+=("--force")
-      su -c "$PHP_BIN ${_php_args[*]}" -s /bin/bash $HTTP_USER > "$user_result_tsv" 2> "$log_file"
+      # -d max_execution_time=0: recreating every selected file of a
+      # large account can run well over an hour; without this the PHP
+      # CLI process is killed by PHP's own execution-time limit
+      # (typically inherited from the webserver's php.ini) mid-run.
+      su -c "$PHP_BIN -d max_execution_time=0 ${_php_args[*]}" -s /bin/bash $HTTP_USER > "$user_result_tsv" 2> "$log_file"
       _rc=$?
    else
       echo -e "path\tbytes_written\tstatus\tdetail" > "$user_result_tsv"

restore_bad_signature.sh

@@ -167,6 +167,8 @@ usage() {
 clean_up() {
 
    # Perform program exit housekeeping
+   # Clear EXIT trap first so that the exit below does not fire it again.
+   trap - EXIT
    [[ -n "$restore_php_file" ]] && rm -f "$restore_php_file" 2> /dev/null
    rm -rf "$LOCK_DIR"
    blank_line
@@ -174,6 +176,77 @@ clean_up() {
 
 }
 
+
+check_optional_validation_tools() {
+
+   local _missing_tools=()
+   local _missing_pkgs=()
+   local _desc=()
+
+   command -v identify > /dev/null 2>&1 || {
+      _missing_tools+=("identify")
+      _missing_pkgs+=("imagemagick")
+      _desc+=("identify  (imagemagick)  — PNG / TIFF / BMP / GIF: vollst. Dekodierung statt nur Magic-Bytes")
+   }
+   command -v ffprobe > /dev/null 2>&1 || {
+      _missing_tools+=("ffprobe")
+      _missing_pkgs+=("ffmpeg")
+      _desc+=("ffprobe   (ffmpeg)       — MP4 / MOV / M4V: Container-Parsing statt nur ftyp-Box-Suche")
+   }
+   command -v mp3val > /dev/null 2>&1 || {
+      _missing_tools+=("mp3val")
+      _missing_pkgs+=("mp3val")
+      _desc+=("mp3val    (mp3val)       — MP3: Frame-Struktur-Check statt nur ID3-Signatur")
+   }
+   command -v flac > /dev/null 2>&1 || {
+      _missing_tools+=("flac")
+      _missing_pkgs+=("flac")
+      _desc+=("flac      (flac)         — FLAC: Decode-Test statt nur fLaC-Signatur")
+   }
+   command -v ogginfo > /dev/null 2>&1 || {
+      _missing_tools+=("ogginfo")
+      _missing_pkgs+=("vorbis-tools")
+      _desc+=("ogginfo   (vorbis-tools) — OGG / OGA / OPUS: Container-Check statt nur OggS-Signatur")
+   }
+
+   [[ ${#_missing_tools[@]} -eq 0 ]] && return 0
+
+   if ! $terminal ; then
+      return 0
+   fi
+
+   local _pkg_list="${_missing_pkgs[*]}"
+
+   echo ""
+   echo -e "   \033[33mOptionale Validierungs-Tools fehlen – Checks laufen mit reduzierter Genauigkeit:\033[m"
+   echo ""
+   local _d
+   for _d in "${_desc[@]}" ; do
+      echo "      ${_d}"
+   done
+   echo ""
+   echo -n "   Jetzt installieren?  apt install ${_pkg_list}  [j/N]: "
+   read -r _yn
+   echo ""
+   if [[ "$_yn" =~ ^[jJyY]$ ]] ; then
+      echononl "   Installiere Pakete: ${_pkg_list}.."
+      # shellcheck disable=SC2086
+      if apt-get install -y ${_missing_pkgs[*]} > /dev/null 2>&1 ; then
+         echo_ok
+      else
+         echo_failed
+         echo ""
+         echo "   Bitte manuell installieren:"
+         echo "      apt install ${_pkg_list}"
+      fi
+   else
+      echo "   Übersprungen — Validierung läuft mit reduzierter Genauigkeit."
+   fi
+   echo ""
+
+}
+
+
 is_number() {
 
    return $(test ! -z "${1##*[!0-9]*}" > /dev/null 2>&1);
@@ -323,37 +396,69 @@ validate_recovered_file() {
          fi
          ;;
       png)
-         local _head
-         _head="$(head -c8 "$_f" 2> /dev/null | od -An -tx1 | tr -d ' \n')"
-         if [[ "$_head" = "89504e470d0a1a0a" ]] ; then
-            echo "VALID|PNG signature ok"
+         if command -v identify > /dev/null 2>&1 ; then
+            if identify -regard-warnings "$_f" > /dev/null 2>&1 ; then
+               echo "VALID|ImageMagick 'identify' decoded PNG ok"
+            else
+               echo "INVALID|ImageMagick 'identify' failed to decode PNG"
+            fi
          else
-            echo "INVALID|PNG signature missing"
+            local _head
+            _head="$(head -c8 "$_f" 2> /dev/null | od -An -tx1 | tr -d ' \n')"
+            if [[ "$_head" = "89504e470d0a1a0a" ]] ; then
+               echo "VALID|PNG signature ok (identify not installed — no deep check)"
+            else
+               echo "INVALID|PNG signature missing"
+            fi
          fi
          ;;
       gif)
-         local _head6
-         _head6="$(head -c6 "$_f" 2> /dev/null)"
-         if [[ "$_head6" = "GIF87a" || "$_head6" = "GIF89a" ]] ; then
-            echo "VALID|GIF signature ok"
+         if command -v identify > /dev/null 2>&1 ; then
+            if identify -regard-warnings "$_f" > /dev/null 2>&1 ; then
+               echo "VALID|ImageMagick 'identify' decoded GIF ok"
+            else
+               echo "INVALID|ImageMagick 'identify' failed to decode GIF"
+            fi
          else
-            echo "INVALID|GIF signature missing"
+            local _head6
+            _head6="$(head -c6 "$_f" 2> /dev/null)"
+            if [[ "$_head6" = "GIF87a" || "$_head6" = "GIF89a" ]] ; then
+               echo "VALID|GIF signature ok (identify not installed — no deep check)"
+            else
+               echo "INVALID|GIF signature missing"
+            fi
          fi
          ;;
       bmp)
-         if [[ "$(head -c2 "$_f" 2> /dev/null)" = "BM" ]] ; then
-            echo "VALID|BMP signature ok"
+         if command -v identify > /dev/null 2>&1 ; then
+            if identify -regard-warnings "$_f" > /dev/null 2>&1 ; then
+               echo "VALID|ImageMagick 'identify' decoded BMP ok"
+            else
+               echo "INVALID|ImageMagick 'identify' failed to decode BMP"
+            fi
          else
-            echo "INVALID|BMP signature missing"
+            if [[ "$(head -c2 "$_f" 2> /dev/null)" = "BM" ]] ; then
+               echo "VALID|BMP signature ok (identify not installed — no deep check)"
+            else
+               echo "INVALID|BMP signature missing"
+            fi
          fi
          ;;
       tif|tiff)
-         local _head4
-         _head4="$(head -c4 "$_f" 2> /dev/null | od -An -tx1 | tr -d ' \n')"
-         if [[ "$_head4" = "49492a00" || "$_head4" = "4d4d002a" ]] ; then
-            echo "VALID|TIFF signature ok"
+         if command -v identify > /dev/null 2>&1 ; then
+            if identify -regard-warnings "$_f" > /dev/null 2>&1 ; then
+               echo "VALID|ImageMagick 'identify' decoded TIFF ok"
+            else
+               echo "INVALID|ImageMagick 'identify' failed to decode TIFF"
+            fi
          else
-            echo "INVALID|TIFF signature missing"
+            local _head4
+            _head4="$(head -c4 "$_f" 2> /dev/null | od -An -tx1 | tr -d ' \n')"
+            if [[ "$_head4" = "49492a00" || "$_head4" = "4d4d002a" ]] ; then
+               echo "VALID|TIFF signature ok (identify not installed — no deep check)"
+            else
+               echo "INVALID|TIFF signature missing"
+            fi
          fi
          ;;
       pnm|pgm|ppm|pbm)
@@ -380,22 +485,57 @@ validate_recovered_file() {
          if [[ "$_head8o" = "d0cf11e0a1b11ae1" ]] ; then
             echo "VALID|OLE2/CFBF container signature ok - this is a password-protected Office file (encrypted package), not a plain zip, so the zip check does not apply; open it with the password to verify content"
          elif command -v unzip > /dev/null 2>&1 ; then
-            if unzip -tq "$_f" > /dev/null 2>&1 ; then
+            # Run unzip inside setsid so it has no controlling terminal.
+            # Without setsid, a password-protected ZIP causes unzip to try
+            # opening /dev/tty to prompt for the password. When running in
+            # the background of a tmux session this generates SIGTTIN, which
+            # STOPS the process (ps state T). A stopped process cannot receive
+            # SIGTERM, so timeout hangs indefinitely waiting for a child that
+            # will never exit. With setsid the /dev/tty open fails immediately
+            # with ENXIO and unzip exits with a non-zero code instead.
+            # -k 5: send SIGKILL 5 s after SIGTERM in case the process is
+            # still alive (e.g. stopped or in uninterruptible sleep).
+            local _unzip_exit
+            timeout -k 5 120 setsid unzip -tq "$_f" < /dev/null > /dev/null 2>&1
+            _unzip_exit=$?
+            if [[ $_unzip_exit -eq 0 ]] ; then
                echo "VALID|zip integrity ok"
+            elif [[ $_unzip_exit -eq 124 || $_unzip_exit -eq 137 ]] ; then
+               # 124 = killed by SIGTERM after timeout, 137 = killed by SIGKILL (128+9)
+               echo "UNVERIFIED|zip integrity check timed out after 120 s (file may be very large or corrupt; check manually with: unzip -t \"$_f\")"
             else
                local _badentry
-               _badentry="$(trim "$(unzip -t "$_f" 2>&1 | grep -v '^Archive:' | grep -v '^[[:space:]]*$' | head -1)")"
-               echo "INVALID|zip integrity check failed${_badentry:+ (${_badentry})}"
+               _badentry="$(trim "$(timeout -k 5 120 setsid unzip -t "$_f" < /dev/null 2>&1 | grep -v '^Archive:' | grep -v '^[[:space:]]*$' | head -1)")"
+               if echo "$_badentry" | grep -qi "password\|encrypt\|need PK compat" ; then
+                  echo "UNVERIFIED|zip is password-protected (cannot verify without password${_badentry:+; unzip says: ${_badentry}})"
+               else
+                  echo "INVALID|zip integrity check failed${_badentry:+ (${_badentry})}"
+               fi
             fi
          else
             echo "UNVERIFIED|unzip not installed"
          fi
          ;;
       mp4|mov|m4v)
-         if head -c 64 "$_f" 2> /dev/null | grep -aq "ftyp" ; then
-            echo "VALID|mp4 ftyp box found"
+         if command -v ffprobe > /dev/null 2>&1 ; then
+            local _ffprobe_out _ffprobe_exit
+            _ffprobe_out="$(ffprobe -v error -show_streams "$_f" 2>&1)"
+            _ffprobe_exit=$?
+            if [[ $_ffprobe_exit -eq 0 ]] ; then
+               local _streams
+               _streams="$(echo "$_ffprobe_out" | grep -c '\[STREAM\]' || true)"
+               echo "VALID|ffprobe parsed container ok (${_streams} stream(s) found)"
+            else
+               local _ffprobe_err
+               _ffprobe_err="$(echo "$_ffprobe_out" | head -1)"
+               echo "INVALID|ffprobe failed to parse container${_ffprobe_err:+ (${_ffprobe_err})}"
+            fi
          else
-            echo "INVALID|mp4 ftyp box not found"
+            if head -c 64 "$_f" 2> /dev/null | grep -aq "ftyp" ; then
+               echo "VALID|mp4 ftyp box found (ffprobe not installed — no deep check)"
+            else
+               echo "INVALID|mp4 ftyp box not found"
+            fi
          fi
          ;;
       doc|xls|ppt|ole|msi)
@@ -495,6 +635,72 @@ validate_recovered_file() {
             echo "INVALID|GIMP (gimp xcf) signature missing"
          fi
          ;;
+      mp3)
+         if command -v mp3val > /dev/null 2>&1 ; then
+            local _mp3val_out
+            _mp3val_out="$(mp3val "$_f" 2>&1)"
+            if echo "$_mp3val_out" | grep -q 'No errors found' ; then
+               echo "VALID|mp3val: no errors found"
+            else
+               local _mp3_err
+               _mp3_err="$(echo "$_mp3val_out" | grep -iv '^mp3val\|^$' | head -2 | tr '\n' ' ' | sed 's/ $//')"
+               echo "INVALID|mp3val reported errors${_mp3_err:+ (${_mp3_err})}"
+            fi
+         else
+            local _head3 _head2hex
+            _head3="$(head -c3 "$_f" 2>/dev/null)"
+            _head2hex="$(head -c2 "$_f" 2>/dev/null | od -An -tx1 | tr -d ' \n')"
+            if [[ "$_head3" = "ID3" ]] || echo "$_head2hex" | grep -qE '^fff[bef2]' ; then
+               echo "VALID|MP3 ID3 tag / MPEG sync ok (mp3val not installed — no deep check)"
+            else
+               echo "INVALID|MP3: no ID3 header or MPEG frame sync found"
+            fi
+         fi
+         ;;
+      flac)
+         if command -v flac > /dev/null 2>&1 ; then
+            local _flac_out _flac_exit
+            _flac_out="$(flac --silent --test "$_f" 2>&1)"
+            _flac_exit=$?
+            if [[ $_flac_exit -eq 0 ]] ; then
+               echo "VALID|flac --test: ok"
+            else
+               local _flac_err
+               _flac_err="$(echo "$_flac_out" | grep -v '^$' | tail -1)"
+               echo "INVALID|flac --test failed${_flac_err:+ (${_flac_err})}"
+            fi
+         else
+            local _head4hex
+            _head4hex="$(head -c4 "$_f" 2>/dev/null | od -An -tx1 | tr -d ' \n')"
+            if [[ "$_head4hex" = "664c6143" ]] ; then
+               echo "VALID|FLAC 'fLaC' signature ok (flac not installed — no deep check)"
+            else
+               echo "INVALID|FLAC 'fLaC' signature missing"
+            fi
+         fi
+         ;;
+      ogg|oga|ogv|opus)
+         if command -v ogginfo > /dev/null 2>&1 ; then
+            local _ogg_out _ogg_exit
+            _ogg_out="$(ogginfo "$_f" 2>&1)"
+            _ogg_exit=$?
+            if [[ $_ogg_exit -eq 0 ]] ; then
+               echo "VALID|ogginfo: container parsed ok"
+            else
+               local _ogg_err
+               _ogg_err="$(echo "$_ogg_out" | grep -iv '^Processing\|^$' | head -2 | tr '\n' ' ' | sed 's/ $//')"
+               echo "INVALID|ogginfo failed${_ogg_err:+ (${_ogg_err})}"
+            fi
+         else
+            local _head4ogg
+            _head4ogg="$(head -c4 "$_f" 2>/dev/null)"
+            if [[ "$_head4ogg" = "OggS" ]] ; then
+               echo "VALID|OGG 'OggS' signature ok (ogginfo not installed — no deep check)"
+            else
+               echo "INVALID|OGG 'OggS' signature missing"
+            fi
+         fi
+         ;;
       wav)
          local _riff _wave
          _riff="$(head -c4 "$_f" 2> /dev/null)"
@@ -582,6 +788,15 @@ validate_recovered_file() {
 ## - PDF structural check shared by the 'pdf' case and the 'ai'
 ## - (PDF-compatible) case. Sets $_pdf_check_detail, returns 0/1.
 ## -
+## - qpdf exit codes:
+## -   0  no problems
+## -   2  structural errors   → file is genuinely corrupt/unreadable
+## -   3  warnings only       → minor spec non-conformances; every real
+## -                            viewer opens the file without issues
+## - Only exit code 2 is treated as INVALID here.  Exit code 3 (warnings)
+## - is reported as VALID with a note, preventing false positives for
+## - real-world PDFs that have trivial non-conformances.
+## -
 _pdf_check() {
    local _f="$1"
    if [[ "$(head -c5 "$_f" 2> /dev/null)" != "%PDF-" ]] ; then
@@ -589,11 +804,22 @@ _pdf_check() {
       return 1
    fi
    if command -v qpdf > /dev/null 2>&1 ; then
-      if qpdf --check "$_f" > /dev/null 2>&1 ; then
+      local _qpdf_out _qpdf_exit
+      _qpdf_out="$(qpdf --check "$_f" 2>&1)"
+      _qpdf_exit=$?
+      if [[ $_qpdf_exit -eq 0 ]] ; then
          _pdf_check_detail="qpdf --check ok"
          return 0
+      elif [[ $_qpdf_exit -eq 3 ]] ; then
+         # Warnings only — no structural errors.  File is readable by all
+         # standard PDF viewers; non-conformances are minor/cosmetic.
+         _pdf_check_detail="qpdf --check ok (warnings only — file is readable)"
+         return 0
       else
-         _pdf_check_detail="qpdf --check failed"
+         # Exit code 2 (or unexpected): genuine structural errors.
+         local _first_err
+         _first_err="$(echo "$_qpdf_out" | grep -i 'error' | head -1 | sed 's/^[[:space:]]*//')"
+         _pdf_check_detail="qpdf --check failed (exit ${_qpdf_exit}${_first_err:+: ${_first_err}})"
          return 1
       fi
    fi
@@ -761,7 +987,9 @@ if mkdir "$LOCK_DIR" 2> /dev/null ; then
 
    # - Remove lockdir when the script finishes, or when it receives a signal
    # -
-   trap clean_up SIGHUP SIGINT SIGTERM
+   # Trap signals AND normal/abnormal exit so that temp files and the
+   # lock directory are always removed — even on an unexpected crash.
+   trap 'clean_up 1' SIGHUP SIGINT SIGTERM EXIT
 
 else
 
@@ -816,7 +1044,6 @@ if ! $_dry_run_explicit && $terminal ; then
                           but write, back up and verify NOTHING"
    echo ""
    echo    "   [2] Real restore    - actually back up, overwrite and verify each file in Nextcloud"
-
    info "Just press Return to use the default: [1] Dry-run."
    echo -n "   Select mode by number [1]: "
    read _mode_choice
@@ -1123,6 +1350,8 @@ done
 mkdir -p "$report_dir" 2> /dev/null
 restore_report_file="${report_dir}/restore_${WEBSITE}_${run_date}.tsv"
 
+check_optional_validation_tools
+
 if $terminal ; then
    echo ""
    if $DRY_RUN ; then
@@ -1164,6 +1393,18 @@ if $terminal ; then
    fi
 fi
 
+if $terminal ; then
+   echo ""
+   echo -e "   \033[1mTemporäre Dateien – werden laufend aktualisiert:\033[m"
+   echo ""
+   echo -e "   Fortschritt / Debug-Meldungen (PHP-Ausgabe auf STDERR):"
+   echo -e "      \033[1mtail -f ${log_file}\033[m"
+   echo ""
+   echo -e "   Rohergebnis pro Account (PHP-Ausgabe auf STDOUT, Datei für Datei):"
+   echo -e "      \033[1mtail -f ${LOCK_DIR}/result_<account>.tsv\033[m"
+   echo ""
+fi
+
 
 {
    echo "=================================================================="
@@ -1228,6 +1469,13 @@ if ($oldWorkingDir === false) {
 }
 chdir(__DIR__);
 require_once __DIR__ . '/lib/base.php';
+// Nextcloud's own bootstrap (lib/base.php) unconditionally calls
+// set_time_limit(3600) as part of the require above - this OVERRIDES
+// whatever -d max_execution_time was passed on the PHP command line,
+// since it is a later, explicit runtime call. Undo that here, now that
+// the require is done, so restoring a large account isn't killed
+// after exactly one hour regardless of the CLI flag.
+set_time_limit(0);
 chdir($oldWorkingDir);
 
 if (function_exists('posix_getuid') && posix_getuid() === 0) {
@@ -1498,10 +1746,15 @@ for _user in "${selected_user_arr[@]}" ; do
    fi
 
    if [[ -s "$list_file" ]] ; then
+      # -d max_execution_time=0: re-validating and writing back every
+      # selected file of a large account can run well over an hour;
+      # without this the PHP CLI process is killed by PHP's own
+      # execution-time limit (typically inherited from the webserver's
+      # php.ini) mid-run.
       if $DRY_RUN ; then
-         su -c "$PHP_BIN $restore_php_file $_user $list_file --dry-run" -s /bin/bash $HTTP_USER > "$user_result_tsv" 2> "$log_file"
+         su -c "$PHP_BIN -d max_execution_time=0 $restore_php_file $_user $list_file --dry-run" -s /bin/bash $HTTP_USER > "$user_result_tsv" 2> "$log_file"
       else
-         su -c "$PHP_BIN $restore_php_file $_user $list_file" -s /bin/bash $HTTP_USER > "$user_result_tsv" 2> "$log_file"
+         su -c "$PHP_BIN -d max_execution_time=0 $restore_php_file $_user $list_file" -s /bin/bash $HTTP_USER > "$user_result_tsv" 2> "$log_file"
       fi
       _rc=$?
    else

scan_bad_signature.sh

@@ -582,6 +582,14 @@ fwrite(STDERR, "DEBUG: vor require lib/base.php\n");
 require_once __DIR__ . '/lib/base.php';
 fwrite(STDERR, "DEBUG: nach require lib/base.php - Bootstrap abgeschlossen\n");
 
+// Nextcloud's own bootstrap (lib/base.php) unconditionally calls
+// set_time_limit(3600) as part of require_once above - this OVERRIDES
+// whatever -d max_execution_time was passed on the PHP command line,
+// since it is a later, explicit runtime call. Undo that here, now that
+// the require is done, so a full-content scan of a large account isn't
+// killed after exactly one hour regardless of the CLI flag.
+set_time_limit(0);
+
 chdir($oldWorkingDir);
 
 if (function_exists('posix_getuid') && posix_getuid() === 0) {
@@ -771,6 +779,18 @@ if $terminal ; then
    fi
 fi
 
+if $terminal ; then
+   echo ""
+   echo -e "   \033[1mTemporäre Dateien – werden laufend aktualisiert:\033[m"
+   echo ""
+   echo -e "   Fortschritt / Debug-Meldungen (PHP-Ausgabe auf STDERR):"
+   echo -e "      \033[1mtail -f ${log_file}\033[m"
+   echo ""
+   echo -e "   Rohergebnis pro Account (PHP-Ausgabe auf STDOUT, Datei für Datei):"
+   echo -e "      \033[1mtail -f ${LOCK_DIR}/scan_<account>.tsv\033[m"
+   echo ""
+fi
+
 
 # -----
 # - Main part of the script
@@ -810,7 +830,12 @@ for _user in "${selected_user_arr[@]}" ; do
    } >> "$report_file"
 
    echononl "   Scanning account \033[1;37m${_user}\033[m.."
-   su -c "$PHP_BIN $scan_php_file $_user" -s /bin/bash $HTTP_USER > "$user_tsv" 2> "$log_file"
+   # -d max_execution_time=0: a full-content read of every file of a
+   # large account can easily run well over an hour; without this the
+   # PHP CLI process is killed by PHP's own execution-time limit
+   # (typically inherited from the webserver's php.ini) mid-scan, long
+   # before any actual error in the account's files.
+   su -c "$PHP_BIN -d max_execution_time=0 $scan_php_file $_user" -s /bin/bash $HTTP_USER > "$user_tsv" 2> "$log_file"
    _rc=$?
 
    if [[ $_rc -ne 0 ]]; then