Merging upstream version 0.27.

Signed-off-by: Daniel Baumann <daniel@debian.org>
2025-03-04 07:39:30 +01:00 · 2025-03-04 07:39:30 +01:00 · 5e422e043e
commit 5e422e043e
parent 619358407d
83 changed files with 980 additions and 726 deletions
--- a/45
+++ b/45
@ -1,3 +1,20 @@
 2025-02-28  Antonio Diaz Diaz  <antonio@gnu.org>
 	* Version 0.27 released.
 	* common_decode.cc (format_member_name): Print seconds since epoch
 	  if date is out of range. Use at least 4 digits to print years.
 	  Print typeflag after the member name if unknown file type.
 	  (make_dirs): stat last dir before trying to create directories.
 	* decode.cc (skip_warn): Diagnose a corrupt tar header.
 	* extended.cc (Extended::parse): Diagnose a CRC mismatch.
 	  New argument 'msg_vecp' for multi-threaded diagnostics.
 	* Many small fixes and improvements to the code and the manual.
 	* tarlz.texi: New chapter 'Creating backups safely'.
 	  (Suggested by Aren Tyr).
 	* check.sh: Require lzip. Create .tar files from .tar.lz files.
 	  Limit '--mtime' test to safe dates. (Reported by Aren Tyr).
 	* testsuite: Add 5 new test files.
 2024-12-07  Antonio Diaz Diaz  <antonio@gnu.org>
 	* Version 0.26 released.
@ -73,8 +90,7 @@
 	* Lzlib 1.12 or newer is now required.
 	* decode.cc (decode): Skip members without name except when listing.
 	  decode_lz.cc (dworker): Likewise. (Reported by Florian Schmaus).
-	* New options '-z, --compress' and '-o, --output'.
+	* New options '-z, --compress', '-o, --output', and '--warn-newer'.
 	* New option '--warn-newer'.
 	* tarlz.texi (Invoking tarlz): Document concatenation to stdout.
 	* check.sh: Fix the '--diff' test on OS/2. (Reported by Elbert Pol).
@ -97,10 +113,10 @@
 2020-07-30  Antonio Diaz Diaz  <antonio@gnu.org>
 	* Version 0.17 released.
-	* New option '--mtime'.
+	* New options '--mtime' and '-p, --preserve-permissions'.
 	* New option '-p, --preserve-permissions'.
 	* Implement multi-threaded '-d, --diff'.
 	* list_lz.cc: Rename to decode_lz.cc.
 	  (decode_lz): Limit num_workers to number of members.
 	* main.cc (main): Report an error if a file name is empty or if the
 	  archive is specified more than once.
 	* lzip_index.cc: Improve messages for corruption in last header.
@ -125,8 +141,7 @@
 2019-03-12  Antonio Diaz Diaz  <antonio@gnu.org>
 	* Version 0.14 released.
-	* New option '--exclude'.
+	* New options '--exclude' and '-h, --dereference'.
 	* New option '-h, --dereference'.
 	* Short option name '-h' no longer means '--help'.
 	* create.cc: Implement '-A, --concatenate' and '-r, --append' to
 	  uncompressed archives and to standard output.
@ -145,8 +160,7 @@
 	* create.cc (fill_headers): Fix use of st_rdev instead of st_dev.
 	* Save just numerical uid/gid if user or group not in database.
 	* extract.cc (format_member_name): Print devmajor and devminor.
-	* New option '-d, --diff'.
+	* New options '-d, --diff' and '--ignore-ids'.
 	* New option '--ignore-ids'.
 	* extract.cc: Fast '-t, --list' on seekable uncompressed archives.
 2019-02-13  Antonio Diaz Diaz  <antonio@gnu.org>
@ -161,8 +175,7 @@
 2019-01-31  Antonio Diaz Diaz  <antonio@gnu.org>
 	* Version 0.10 released.
-	* New option '--bsolid'.
+	* New options '--bsolid' and '-B, --data-size'.
 	* New option '-B, --data-size'.
 	* create.cc: Set ustar name to zero if extended header is used.
 2019-01-22  Antonio Diaz Diaz  <antonio@gnu.org>
@ -185,8 +198,7 @@
 2018-11-23  Antonio Diaz Diaz  <antonio@gnu.org>
 	* Version 0.7 released.
-	* New option '--keep-damaged'.
+	* New options '--keep-damaged' and '--no-solid'.
 	* New option '--no-solid'.
 	* create.cc (archive_write): Minimize dictionary size.
 	  Detect and skip archive in '-A', '-c', and '-r'.
 	* main.cc (show_version): Show the version of lzlib being used.
@ -195,7 +207,7 @@
 	* Version 0.6 released.
 	* New option '-A, --concatenate'.
-	* Option '--ignore-crc' replaced with '--missing-crc'.
+	* Replace option '--ignore-crc' with '--missing-crc'.
 	* create.cc (add_member): Check that uid, gid, mtime, devmajor,
 	  and devminor are in ustar range.
 	* configure: Accept appending to CXXFLAGS; 'CXXFLAGS+=OPTIONS'.
@ -220,11 +232,10 @@
 	* Version 0.3 released.
 	* Rename project to 'tarlz' from 'pmtar' (Poor Man's Tar).
-	* New option '-C, --directory'.
+	* New options '-C, --directory' and '-r, --append'.
 	* Implement lzip compression of members at archive creation.
 	* New option '-r, --append'.
 	* New options '--owner' and '--group'.
 	* New options '--asolid', '--dsolid', and '--solid'.
 	* Implement lzip compression of members at archive creation.
 	* Implement file appending to compressed archive.
 	* Implement transparent decompression of the archive.
 	* Implement skipping over damaged (un)compressed members.
@ -242,7 +253,7 @@
 	* Version 0.1 released.
-Copyright (C) 2013-2024 Antonio Diaz Diaz.
+Copyright (C) 2013-2025 Antonio Diaz Diaz.
 This file is a collection of facts, and thus it is not copyrightable, but just
 in case, you have unlimited permission to copy, distribute, and modify it.
--- a/12
+++ b/12
@ -4,10 +4,12 @@ You will need a C++98 compiler with support for 'long long', and the
 compression library lzlib installed. (gcc 3.3.6 or newer is recommended).
 I use gcc 6.1.0 and 3.3.6, but the code should compile with any standards
 compliant compiler.
 Gcc is available at http://gcc.gnu.org.
 Lzlib is available at http://www.nongnu.org/lzip/lzlib.html.
 Lzlib must be version 1.12 or newer.
 Gcc is available at http://gcc.gnu.org
 Lzlib is available at http://www.nongnu.org/lzip/lzlib.html
 Lzip is required to run the tests.
 Lzip is available at http://www.nongnu.org/lzip/lzip.html
 The operating system must allow signal handlers read access to objects with
 static storage duration so that the cleanup handler for Control-C can delete
@ -18,6 +20,8 @@ Procedure
 ---------
 1. Unpack the archive if you have not done so already:
 	tarlz -xf tarlz[version].tar.lz
 or
 	tar -xf tarlz[version].tar.lz
 or
 	lzip -cd tarlz[version].tar.lz | tar -xf -
@ -74,7 +78,7 @@ After running 'configure', you can run 'make' and 'make install' as
 explained above.
-Copyright (C) 2013-2024 Antonio Diaz Diaz.
+Copyright (C) 2013-2025 Antonio Diaz Diaz.
 This file is free documentation: you have unlimited permission to copy,
 distribute, and modify it.
--- a/Makefile.in
+++ b/Makefile.in
@ -135,42 +135,34 @@ dist : doc
 	  $(DISTNAME)/*.cc \
 	  $(DISTNAME)/testsuite/check.sh \
 	  $(DISTNAME)/testsuite/test.txt \
 	  $(DISTNAME)/testsuite/test.txt.tar \
 	  $(DISTNAME)/testsuite/test_bad1.txt.tar \
 	  $(DISTNAME)/testsuite/test_bad[12].txt \
 	  $(DISTNAME)/testsuite/rfoo \
 	  $(DISTNAME)/testsuite/rbar \
 	  $(DISTNAME)/testsuite/rbaz \
 	  $(DISTNAME)/testsuite/test3.tar \
 	  $(DISTNAME)/testsuite/test3_nn.tar \
 	  $(DISTNAME)/testsuite/test3_eoa[1-4].tar \
 	  $(DISTNAME)/testsuite/test3_gh[1-4].tar \
 	  $(DISTNAME)/testsuite/test3_bad[1-5].tar \
 	  $(DISTNAME)/testsuite/test3_dir.tar \
 	  $(DISTNAME)/testsuite/t155.tar \
 	  $(DISTNAME)/testsuite/t155_fv[1-3].tar \
 	  $(DISTNAME)/testsuite/eoa_blocks.tar \
 	  $(DISTNAME)/testsuite/em.lz \
 	  $(DISTNAME)/testsuite/test.txt.lz \
 	  $(DISTNAME)/testsuite/test.txt.tar.lz \
 	  $(DISTNAME)/testsuite/test_bad[12].txt.tar.lz \
 	  $(DISTNAME)/testsuite/test3.tar.lz \
 	  $(DISTNAME)/testsuite/test3_eoa[1-5].tar.lz \
-	  $(DISTNAME)/testsuite/test3_gh[1-6].tar.lz \
+	  $(DISTNAME)/testsuite/test3_gh[1-8].tar.lz \
 	  $(DISTNAME)/testsuite/test3_nn.tar.lz \
 	  $(DISTNAME)/testsuite/test3_sm[1-4].tar.lz \
 	  $(DISTNAME)/testsuite/test3_bad[1-6].tar.lz \
 	  $(DISTNAME)/testsuite/test3_crc.tar.lz \
 	  $(DISTNAME)/testsuite/test3_uk.tar.lz \
 	  $(DISTNAME)/testsuite/test3_dir.tar.lz \
 	  $(DISTNAME)/testsuite/test3_dot.tar.lz \
 	  $(DISTNAME)/testsuite/tar_in_tlz[12].tar.lz \
 	  $(DISTNAME)/testsuite/tlz_in_tar[12].tar \
 	  $(DISTNAME)/testsuite/ts_in_link.tar.lz \
 	  $(DISTNAME)/testsuite/t155.tar.lz \
-	  $(DISTNAME)/testsuite/t155_fv[1-6].tar.lz \
+	  $(DISTNAME)/testsuite/t155_fv[1-7].tar.lz \
 	  $(DISTNAME)/testsuite/dotdot[1-5].tar.lz \
 	  $(DISTNAME)/testsuite/ug32767.tar.lz \
 	  $(DISTNAME)/testsuite/ug32chars.tar.lz \
-	  $(DISTNAME)/testsuite/eoa_blocks.tar.lz
+	  $(DISTNAME)/testsuite/eoa_blocks.lz
 	rm -f $(DISTNAME)
 clean :
--- a/36
+++ b/36
@ -1,13 +1,33 @@
-Changes in version 0.26:
+Changes in version 0.27:
-tarlz now exits with error status 2 if any empty lzip member is found in a
+tarlz now prints seconds since epoch if a file date is out of range.
 multimember compressed archive.
-Scalability of parallel compressed creation and decoding has been increased.
+tarlz now uses at least 4 digits to print years.
-A diagnostic message for read error has been improved.
+'tarlz -tv' now prints the value of typeflag after the member name for
 unknown file types.
-The chapter 'Syntax of command-line arguments' has been added to the manual.
+tarlz now prints a diagnostic when it finds a corrupt tar header (or random
 data where a tar header is expected).
-'make check' now skips time stamps out of range or not recognized by system
+tarlz now diagnoses CRC mismatches in extended records separately.
-tools. (Reported by J Dean).
+
 Multi-threaded decoding now prints diagnostics about CRC mismatches and
 unknown keywords in extended records in the correct order.
 Many small fixes and improvements have been made to the code and the manual.
 The chapter 'Creating backups safely' has been added to the manual.
 (Suggested by Aren Tyr).
 Lzip is now required to run the tests because I have not found any other
 portable and reliable way to tell compressed archives from non-compressed.
 Where possible, .tar archives for the testsuite are now decompressed from
 their .tar.lz versions instead of distributed.
 'make check' no longer tests '--mtime' with extreme dates to avoid test
 failures caused by differences with the system tool 'touch'.
 (Reported by Aren Tyr).
 5 new test files have been added to the testsuite.
--- a/4
+++ b/4
@ -15,7 +15,7 @@ compressed archives.
 Keeping the alignment between tar members and lzip members has two
 advantages. It adds an indexed lzip layer on top of the tar archive, making
-it possible to decode the archive safely in parallel. It also minimizes the
+it possible to decode the archive safely in parallel. It also reduces the
 amount of data lost in case of corruption. Compressing a tar archive with
 plzip may even double the amount of files lost for each lzip member damaged
 because it does not keep the members aligned.
@ -93,7 +93,7 @@ Tarlz uses Arg_parser for command-line argument parsing:
 http://www.nongnu.org/arg-parser/arg_parser.html
-Copyright (C) 2013-2024 Antonio Diaz Diaz.
+Copyright (C) 2013-2025 Antonio Diaz Diaz.
 This file is free documentation: you have unlimited permission to copy,
 distribute, and modify it.
--- a/archive_reader.cc
+++ b/archive_reader.cc
@ -1,5 +1,5 @@
 /* Tarlz - Archiver with multimember lzip compression
-   Copyright (C) 2013-2024 Antonio Diaz Diaz.
+   Copyright (C) 2013-2025 Antonio Diaz Diaz.
   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
@ -82,10 +82,9 @@ Archive_descriptor::Archive_descriptor( const std::string & archive_name )
 int Archive_reader_base::parse_records( Extended & extended,
-                                        const Tar_header header,
+                     const Tar_header header, Resizable_buffer & rbuf,
-                                        Resizable_buffer & rbuf,
+                     const char * const default_msg, const bool permissive,
-                                        const char * const default_msg,
+                     std::vector< std::string > * const msg_vecp )
                                        const bool permissive )
  {
  const long long edsize = parse_octal( header + size_o, size_l );
  const long long bufsize = round_up( edsize );
@ -95,7 +94,7 @@ int Archive_reader_base::parse_records( Extended & extended,
  if( !rbuf.resize( bufsize ) ) return err( -1, mem_msg );
  e_msg_ = ""; e_code_ = 0;
  int retval = read( rbuf.u8(), bufsize );	// extended records buffer
-  if( retval == 0 && !extended.parse( rbuf(), edsize, permissive ) )
+  if( retval == 0 && !extended.parse( rbuf(), edsize, permissive, msg_vecp ) )
    retval = 2;
  if( retval && !*e_msg_ ) e_msg_ = default_msg;
  return retval;
@ -156,16 +155,9 @@ int Archive_reader::read( uint8_t * const buf, const int size )
    const int rd = LZ_decompress_read( decoder, buf + sz, size - sz );
    if( rd < 0 )
      {
      const unsigned long long old_pos = LZ_decompress_total_in_size( decoder );
      if( LZ_decompress_sync_to_member( decoder ) < 0 )
        internal_error( "library error (LZ_decompress_sync_to_member)." );
-      e_skip_ = true; set_error_status( 2 );
+      e_skip_ = true; set_error_status( 2 ); return err( 2, "", 0, sz, true );
      const unsigned long long new_pos = LZ_decompress_total_in_size( decoder );
      // lzlib < 1.8 does not update total_in_size when syncing to member
      if( new_pos >= old_pos && new_pos < LLONG_MAX )
        return err( 2, "", 0, sz, true );
      return err( -1, "Skipping to next header failed. "
                      "Lzlib 1.8 or newer required.", 0, sz );
      }
    if( rd == 0 && LZ_decompress_finished( decoder ) == 1 )
      { return err( -2, end_msg, 0, sz ); }
--- a/archive_reader.h
+++ b/archive_reader.h
@ -1,5 +1,5 @@
 /* Tarlz - Archiver with multimember lzip compression
-   Copyright (C) 2013-2024 Antonio Diaz Diaz.
+   Copyright (C) 2013-2025 Antonio Diaz Diaz.
   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
@ -65,9 +65,10 @@ public:
     If !OK, fills all the e_* variables. */
  virtual int read( uint8_t * const buf, const int size ) = 0;
-  int parse_records( Extended & extended, const Tar_header header,
+  int parse_records( Extended & extended,
-                     Resizable_buffer & rbuf, const char * const default_msg,
+                     const Tar_header header, Resizable_buffer & rbuf,
-                     const bool permissive );
+                     const char * const default_msg, const bool permissive,
                     std::vector< std::string > * const msg_vecp = 0 );
  };
@ -112,7 +113,7 @@ public:
  long long mdata_end() const { return mdata_end_; }
  bool at_member_end() const { return data_pos_ == mdata_end_; }
-  // Resets decoder and sets position to the start of the member.
+  // Reset decoder and set position to the start of the member.
  void set_member( const long i );
  int read( uint8_t * const buf, const int size );
--- a/arg_parser.cc
+++ b/arg_parser.cc
@ -1,5 +1,5 @@
 /* Arg_parser - POSIX/GNU command-line argument parser. (C++ version)
-   Copyright (C) 2006-2024 Antonio Diaz Diaz.
+   Copyright (C) 2006-2025 Antonio Diaz Diaz.
   This library is free software. Redistribution and use in source and
   binary forms, with or without modification, are permitted provided
--- a/arg_parser.h
+++ b/arg_parser.h
@ -1,5 +1,5 @@
 /* Arg_parser - POSIX/GNU command-line argument parser. (C++ version)
-   Copyright (C) 2006-2024 Antonio Diaz Diaz.
+   Copyright (C) 2006-2025 Antonio Diaz Diaz.
   This library is free software. Redistribution and use in source and
   binary forms, with or without modification, are permitted provided
--- a/common.cc
+++ b/common.cc
@ -1,5 +1,5 @@
 /* Tarlz - Archiver with multimember lzip compression
-   Copyright (C) 2013-2024 Antonio Diaz Diaz.
+   Copyright (C) 2013-2025 Antonio Diaz Diaz.
   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
--- a/common_decode.cc
+++ b/common_decode.cc
@ -1,5 +1,5 @@
 /* Tarlz - Archiver with multimember lzip compression
-   Copyright (C) 2013-2024 Antonio Diaz Diaz.
+   Copyright (C) 2013-2025 Antonio Diaz Diaz.
   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
@ -117,53 +117,56 @@ bool block_is_zero( const uint8_t * const buf, const int size )
 bool format_member_name( const Extended & extended, const Tar_header header,
                         Resizable_buffer & rbuf, const bool long_format )
  {
-  if( long_format )
+  if( !long_format )
    {
-    format_mode_string( header, rbuf() );
+    if( !rbuf.resize( extended.path().size() + 2 ) ) return false;
-    const int group_string_len =
+    snprintf( rbuf(), rbuf.size(), "%s\n", extended.path().c_str() );
-      format_user_group_string( extended, header, rbuf() + mode_string_size );
+    return true;
-    int offset = mode_string_size + group_string_len;
+    }
-    const time_t mtime = extended.mtime().sec();
+  format_mode_string( header, rbuf() );
-    struct tm t;
+  const int group_string_len =
-    if( !localtime_r( &mtime, &t ) )			// if local time fails
+    format_user_group_string( extended, header, rbuf() + mode_string_size );
-      { time_t z = 0; if( !gmtime_r( &z, &t ) )		// use UTC, the epoch
+  int offset = mode_string_size + group_string_len;
-        { t.tm_year = 70; t.tm_mon = t.tm_hour = t.tm_min = 0; t.tm_mday = 1; } }
+  const time_t mtime = extended.mtime().sec();
-    const Typeflag typeflag = (Typeflag)header[typeflag_o];
+  struct tm t;
-    const bool islink = typeflag == tf_link || typeflag == tf_symlink;
+  char buf[32];	// if local time and UTC fail, use seconds since epoch
-    const char * const link_string = !islink ? "" :
+  if( localtime_r( &mtime, &t ) || gmtime_r( &mtime, &t ) )
-                         ( ( typeflag == tf_link ) ? " link to " : " -> " );
+    snprintf( buf, sizeof buf, "%04d-%02u-%02u %02u:%02u", 1900 + t.tm_year,
-    // print "user/group size" in a field of width 19 with 8 or more for size
+              1 + t.tm_mon, t.tm_mday, t.tm_hour, t.tm_min );
-    if( typeflag == tf_chardev || typeflag == tf_blockdev )
+  else snprintf( buf, sizeof buf, "%lld", extended.mtime().sec() );
-      {
+  const Typeflag typeflag = (Typeflag)header[typeflag_o];
-      const unsigned devmajor = parse_octal( header + devmajor_o, devmajor_l );
+  const bool islink = typeflag == tf_link || typeflag == tf_symlink;
-      const unsigned devminor = parse_octal( header + devminor_o, devminor_l );
+  const char * const link_string = !islink ? "" :
-      const int width = std::max( 1,
+                       ( ( typeflag == tf_link ) ? " link to " : " -> " );
-        std::max( 8, 19 - group_string_len ) - 1 - decimal_digits( devminor ) );
+  // print "user/group size" in a field of width 19 with 8 or more for size
-      offset += snprintf( rbuf() + offset, rbuf.size() - offset, " %*u,%u",
+  if( typeflag == tf_chardev || typeflag == tf_blockdev )
-                          width, devmajor, devminor );
+    {
-      }
+    const unsigned devmajor = parse_octal( header + devmajor_o, devmajor_l );
-    else
+    const unsigned devminor = parse_octal( header + devminor_o, devminor_l );
-      {
+    const int width = std::max( 1,
-      const int width = std::max( 8, 19 - group_string_len );
+      std::max( 8, 19 - group_string_len ) - 1 - decimal_digits( devminor ) );
-      offset += snprintf( rbuf() + offset, rbuf.size() - offset, " %*llu",
+    offset += snprintf( rbuf() + offset, rbuf.size() - offset, " %*u,%u",
-                          width, extended.file_size() );
+                        width, devmajor, devminor );
      }
    for( int i = 0; i < 2; ++i )	// resize rbuf if not large enough
      {
      const int len = snprintf( rbuf() + offset, rbuf.size() - offset,
                " %4d-%02u-%02u %02u:%02u %s%s%s\n",
                1900 + t.tm_year, 1 + t.tm_mon, t.tm_mday, t.tm_hour,
                t.tm_min, extended.path().c_str(), link_string,
                islink ? extended.linkpath().c_str() : "" );
      if( len + offset < (int)rbuf.size() ) break;
      if( !rbuf.resize( len + offset + 1 ) ) return false;
      }
    }
  else
    {
-    if( rbuf.size() < extended.path().size() + 2 &&
+    const int width = std::max( 8, 19 - group_string_len );
-        !rbuf.resize( extended.path().size() + 2 ) ) return false;
+    offset += snprintf( rbuf() + offset, rbuf.size() - offset, " %*llu",
-    snprintf( rbuf(), rbuf.size(), "%s\n", extended.path().c_str() );
+                        width, extended.file_size() );
    }
  for( int i = 0; i < 2; ++i )	// resize rbuf if not large enough
    {
    const int len = snprintf( rbuf() + offset, rbuf.size() - offset,
              " %s %s%s%s\n", buf, extended.path().c_str(), link_string,
              islink ? extended.linkpath().c_str() : "" );
    if( len + offset < (int)rbuf.size() ) { offset += len; break; }
    if( !rbuf.resize( len + offset + 1 ) ) return false;
    }
  if( rbuf()[0] == '?' )
    {
    if( !rbuf.resize( offset + 25 + 1 ) ) return false;
    snprintf( rbuf() + offset - 1, rbuf.size() - offset,
              ": Unknown file type 0x%02X\n", typeflag );
    }
  return true;
  }
@ -183,9 +186,12 @@ bool show_member_name( const Extended & extended, const Tar_header header,
  }
 /* Return true if file must be skipped.
   Execute -C options if cwd_fd >= 0 (diff or extract). */
 bool check_skip_filename( const Cl_options & cl_opts,
                          std::vector< char > & name_pending,
-                          const char * const filename, const int chdir_fd )
+                          const char * const filename, const int cwd_fd,
                          std::string * const msgp )
  {
  static int c_idx = -1;		// parser index of last -C executed
  if( Exclude::excluded( filename ) ) return true;	// skip excluded files
@ -197,18 +203,19 @@ bool check_skip_filename( const Cl_options & cl_opts,
    {
    if( cl_opts.parser.code( i ) == 'C' ) { chdir_pending = true; continue; }
    if( !nonempty_arg( cl_opts.parser, i ) ) continue;	// skip opts, empty names
-    std::string removed_prefix;
+    std::string removed_prefix;			// prefix of cl argument
    const char * const name = remove_leading_dotslash(
                 cl_opts.parser.argument( i ).c_str(), &removed_prefix );
    if( compare_prefix_dir( name, filename ) ||
        compare_tslash( name, filename ) )
      {
-      print_removed_prefix( removed_prefix );
+      print_removed_prefix( removed_prefix, msgp );
      skip = false; name_pending[i] = false;
-      if( chdir_pending && chdir_fd >= 0 )
+      // only serial decoder sets cwd_fd >= 0 to process -C options
      if( chdir_pending && cwd_fd >= 0 )
        {
        if( c_idx > i )
-          { if( fchdir( chdir_fd ) != 0 )
+          { if( fchdir( cwd_fd ) != 0 )
            { show_error( "Error changing to initial working directory", errno );
              throw Chdir_error(); } c_idx = -1; }
        for( int j = c_idx + 1; j < i; ++j )
@ -234,7 +241,11 @@ bool make_dirs( const std::string & name )
  while( i > 0 && name[i-1] != '/' ) --i;	// remove last component
  while( i > 0 && name[i-1] == '/' ) --i;	// remove more slashes
  const int dirsize = i;		// first slash before last component
  struct stat st;
  if( dirsize > 0 && lstat( std::string( name, 0, dirsize ).c_str(), &st ) == 0 )
    { if( !S_ISDIR( st.st_mode ) ) { errno = ENOTDIR; return false; }
      return true; }
  for( i = 0; i < dirsize; )	// if dirsize == 0, dirname is '/' or empty
    {
    while( i < dirsize && name[i] == '/' ) ++i;
@ -244,7 +255,6 @@ bool make_dirs( const std::string & name )
      {
      const std::string partial( name, 0, i );
      const mode_t mode = S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH;
      struct stat st;
      if( lstat( partial.c_str(), &st ) == 0 )
        { if( !S_ISDIR( st.st_mode ) ) { errno = ENOTDIR; return false; } }
      else if( mkdir( partial.c_str(), mode ) != 0 && errno != EEXIST )
--- a/common_mutex.cc
+++ b/common_mutex.cc
@ -1,5 +1,5 @@
 /* Tarlz - Archiver with multimember lzip compression
-   Copyright (C) 2013-2024 Antonio Diaz Diaz.
+   Copyright (C) 2013-2025 Antonio Diaz Diaz.
   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
@ -131,10 +131,10 @@ bool print_removed_prefix( const std::string & prefix,
    if( prefixes[i] == prefix )
      { xunlock( &mutex ); if( msgp ) msgp->clear(); return false; }
  prefixes.push_back( prefix );
  xunlock( &mutex );
  std::string msg( "Removing leading '" ); msg += prefix;
-  msg += "' from member names.";
+  msg += "' from member names.";	// from archive or command line
  if( msgp ) *msgp = msg; else show_error( msg.c_str() );
  xunlock( &mutex );	// put here to prevent mixing calls to show_error
  return true;
  }
--- a/common_mutex.h
+++ b/common_mutex.h
@ -1,5 +1,5 @@
 /* Tarlz - Archiver with multimember lzip compression
-   Copyright (C) 2013-2024 Antonio Diaz Diaz.
+   Copyright (C) 2013-2025 Antonio Diaz Diaz.
   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
--- a/compress.cc
+++ b/compress.cc
@ -1,5 +1,5 @@
 /* Tarlz - Archiver with multimember lzip compression
-   Copyright (C) 2013-2024 Antonio Diaz Diaz.
+   Copyright (C) 2013-2025 Antonio Diaz Diaz.
   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
@ -212,7 +212,6 @@ int compress_archive( const Cl_options & cl_opts,
  Extended extended;			// metadata from extended records
  Resizable_buffer rbuf;		// headers and extended records buffer
  if( !rbuf.size() ) { show_error( mem_msg ); return 1; }
  const char * const rderr_msg = "Read error";
  bool first_header = true;
  while( true )				// process one tar member per iteration
@ -224,7 +223,7 @@ int compress_archive( const Cl_options & cl_opts,
        show_file_error( filename, "Archive is empty." );
        close( infd ); return 2; }
    if( rd != header_size )
-      { show_file_error( filename, rderr_msg, errno ); close( infd ); return 1; }
+      { show_file_error( filename, rd_err_msg, errno ); close( infd ); return 1; }
    first_header = false;
    const bool is_header = check_ustar_chksum( rbuf.u8() );
@ -259,7 +258,8 @@ int compress_archive( const Cl_options & cl_opts,
      if( !rbuf.resize( total_header_size + bufsize ) )
        { show_file_error( filename, mem_msg ); close( infd ); return 1; }
      if( readblock( infd, rbuf.u8() + total_header_size, bufsize ) != bufsize )
-        { show_file_error( filename, rderr_msg, errno ); close( infd ); return 1; }
+        { show_file_error( filename, rd_err_msg, errno );
          close( infd ); return 1; }
      total_header_size += bufsize;
      if( typeflag == tf_extended )	// do not parse global headers
        {
@ -269,7 +269,7 @@ int compress_archive( const Cl_options & cl_opts,
        if( !rbuf.resize( total_header_size + header_size ) )
          { show_file_error( filename, mem_msg ); close( infd ); return 1; }
        if( readblock( infd, rbuf.u8() + total_header_size, header_size ) != header_size )
-          { show_file_error( filename, errno ? rderr_msg : end_msg, errno );
+          { show_file_error( filename, errno ? rd_err_msg : end_msg, errno );
            close( infd ); return errno ? 1 : 2; }
        if( !check_ustar_chksum( rbuf.u8() ) )
          { show_file_error( filename, bad_hdr_msg ); close( infd ); return 2; }
--- a/6
+++ b/6
@ -1,12 +1,12 @@
 #! /bin/sh
 # configure script for Tarlz - Archiver with multimember lzip compression
-# Copyright (C) 2013-2024 Antonio Diaz Diaz.
+# Copyright (C) 2013-2025 Antonio Diaz Diaz.
 #
 # This configure script is free software: you have unlimited permission
 # to copy, distribute, and modify it.
 pkgname=tarlz
-pkgversion=0.26
+pkgversion=0.27
 progname=tarlz
 srctrigger=doc/${pkgname}.texi
@ -175,7 +175,7 @@ echo "MAKEINFO = ${MAKEINFO}"
 rm -f Makefile
 cat > Makefile << EOF
 # Makefile for Tarlz - Archiver with multimember lzip compression
-# Copyright (C) 2013-2024 Antonio Diaz Diaz.
+# Copyright (C) 2013-2025 Antonio Diaz Diaz.
 # This file was generated automatically by configure. Don't edit.
 #
 # This Makefile is free software: you have unlimited permission
--- a/create.cc
+++ b/create.cc
@ -1,5 +1,5 @@
 /* Tarlz - Archiver with multimember lzip compression
-   Copyright (C) 2013-2024 Antonio Diaz Diaz.
+   Copyright (C) 2013-2025 Antonio Diaz Diaz.
   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
@ -231,7 +231,7 @@ bool store_name( const char * const filename, Extended & extended,
  }
-// add one tar member to the archive
+// add one tar member to the archive and print filename
 int add_member( const char * const filename, const struct stat *,
                const int flag, struct FTW * )
  {
@ -323,7 +323,7 @@ bool copy_file( const int infd, const int outfd, const char * const filename,
    if( max_size >= 0 ) rest -= size;
    const int rd = readblock( infd, buffer, size );
    if( rd != size && errno )
-      { show_file_error( filename, "Read error", errno ); error = true; break; }
+      { show_file_error( filename, rd_err_msg, errno ); error = true; break; }
    if( rd > 0 )
      {
      if( !writeblock_wrapper( outfd, buffer, rd ) ) { error = true; break; }
@ -455,7 +455,7 @@ bool fill_headers( const char * const filename, Extended & extended,
        show_file_error( filename, "Wrong size reading symbolic link.\n"
          "Please, send a bug report to the maintainers of your filesystem, "
          "mentioning\n'wrong st_size of symbolic link'.\nSee "
-          "http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/sys_stat.h.html" );
+          "http://pubs.opengroup.org/onlinepubs/9799919799/basedefs/sys_stat.h.html" );
      set_error_status( 1 ); return false;
      }
    }
@ -607,7 +607,7 @@ int concatenate( const Cl_options & cl_opts )
                                   "Not an appendable tar archive." );
        close( infd ); retval = 2; break; }
    if( !copy_file( infd, outfd, filename, size ) || close( infd ) != 0 )
-      { show_file_error( filename, "Error copying archive", errno );
+      { show_file_error( filename, "Error concatenating archive", errno );
        eoa_pending = false; retval = 1; break; }
    eoa_pending = true;
    if( verbosity >= 1 ) std::fprintf( stderr, "%s\n", filename );
@ -621,6 +621,34 @@ int concatenate( const Cl_options & cl_opts )
  }
 // Return value: 0 = skip arg, 1 = error, 2 = arg done
 int parse_cl_arg( const Cl_options & cl_opts, const int i,
                  int (* add_memberp)( const char * const filename,
                      const struct stat *, const int flag, struct FTW * ) )
  {
  const int code = cl_opts.parser.code( i );
  const std::string & arg = cl_opts.parser.argument( i );
  const char * filename = arg.c_str();	// filename from command line
  if( code == 'C' && chdir( filename ) != 0 )
    { show_file_error( filename, chdir_msg, errno ); return 1; }
  if( code ) return 0;				// skip options
  if( cl_opts.parser.argument( i ).empty() ) return 0;	// skip empty names
  std::string deslashed;		// filename without trailing slashes
  unsigned len = arg.size();
  while( len > 1 && arg[len-1] == '/' ) --len;
  if( len < arg.size() )
    { deslashed.assign( arg, 0, len ); filename = deslashed.c_str(); }
  if( Exclude::excluded( filename ) ) return 0;	// skip excluded files
  struct stat st;
  if( lstat( filename, &st ) != 0 )
    { show_file_error( filename, cant_stat, errno );
      set_error_status( 1 ); return 0; }
  if( nftw( filename, add_memberp, 16, cl_opts.dereference ? 0 : FTW_PHYS ) )
    return 1;					// write error or OOM
  return 2;
  }
 int encode( const Cl_options & cl_opts )
  {
  if( !grbuf.size() ) { show_error( mem_msg ); return 1; }
@ -698,27 +726,11 @@ int encode( const Cl_options & cl_opts )
  int retval = 0;
  for( int i = 0; i < cl_opts.parser.arguments(); ++i )	// parse command line
    {
-    const int code = cl_opts.parser.code( i );
+    const int ret = parse_cl_arg( cl_opts, i, add_member );
-    const std::string & arg = cl_opts.parser.argument( i );
+    if( ret == 0 ) continue;				// skip arg
-    const char * filename = arg.c_str();
+    if( ret == 1 ) { retval = 1; break; }		// error
-    if( code == 'C' && chdir( filename ) != 0 )
+    if( encoder && cl_opts.solidity == dsolid &&	// end of group
-      { show_file_error( filename, chdir_msg, errno ); retval = 1; break; }
+        !archive_write( 0, 0 ) ) { retval = 1; break; }
    if( code ) continue;				// skip options
    if( cl_opts.parser.argument( i ).empty() ) continue; // skip empty names
    std::string deslashed;		// arg without trailing slashes
    unsigned len = arg.size();
    while( len > 1 && arg[len-1] == '/' ) --len;
    if( len < arg.size() )
      { deslashed.assign( arg, 0, len ); filename = deslashed.c_str(); }
    if( Exclude::excluded( filename ) ) continue;	// skip excluded files
    struct stat st;
    if( lstat( filename, &st ) != 0 )	// filename from command line
      { show_file_error( filename, cant_stat, errno ); set_error_status( 1 ); }
    else if( ( retval = nftw( filename, add_member, 16,
                              cl_opts.dereference ? 0 : FTW_PHYS ) ) != 0 )
      break;					// write error
    else if( encoder && cl_opts.solidity == dsolid && !archive_write( 0, 0 ) )
      { retval = 1; break; }
    }
  if( retval == 0 )			// write End-Of-Archive records
--- a/create.h
+++ b/create.h
@ -1,5 +1,5 @@
 /* Tarlz - Archiver with multimember lzip compression
-   Copyright (C) 2013-2024 Antonio Diaz Diaz.
+   Copyright (C) 2013-2025 Antonio Diaz Diaz.
   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
@ -45,3 +45,8 @@ public:
 extern Archive_attrs archive_attrs;
 const char * const cant_stat = "Can't stat input file";
 // defined in create.cc
 int parse_cl_arg( const Cl_options & cl_opts, const int i,
                  int (* add_memberp)( const char * const filename,
                      const struct stat *, const int flag, struct FTW * ) );
--- a/create_lz.cc
+++ b/create_lz.cc
@ -1,5 +1,5 @@
 /* Tarlz - Archiver with multimember lzip compression
-   Copyright (C) 2013-2024 Antonio Diaz Diaz.
+   Copyright (C) 2013-2025 Antonio Diaz Diaz.
   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
@ -250,7 +250,7 @@ public:
  };
-// send one ipacket with tar member metadata to courier
+// send one ipacket with tar member metadata to courier and print filename
 int add_member_lz( const char * const filename, const struct stat *,
                   const int flag, struct FTW * )
  {
@ -300,26 +300,10 @@ extern "C" void * grouper( void * arg )
  for( int i = 0; i < cl_opts.parser.arguments(); ++i )	// parse command line
    {
-    const int code = cl_opts.parser.code( i );
+    const int ret = parse_cl_arg( cl_opts, i, add_member_lz );
-    const std::string & arg = cl_opts.parser.argument( i );
+    if( ret == 0 ) continue;				// skip arg
-    const char * filename = arg.c_str();
+    if( ret == 1 ) exit_fail_mt();			// error
-    if( code == 'C' && chdir( filename ) != 0 )
+    if( cl_opts.solidity == dsolid )			// end of group
      { show_file_error( filename, chdir_msg, errno ); exit_fail_mt(); }
    if( code ) continue;				// skip options
    if( cl_opts.parser.argument( i ).empty() ) continue; // skip empty names
    std::string deslashed;		// arg without trailing slashes
    unsigned len = arg.size();
    while( len > 1 && arg[len-1] == '/' ) --len;
    if( len < arg.size() )
      { deslashed.assign( arg, 0, len ); filename = deslashed.c_str(); }
    if( Exclude::excluded( filename ) ) continue;	// skip excluded files
    struct stat st;
    if( lstat( filename, &st ) != 0 )	// filename from command line
      { show_file_error( filename, cant_stat, errno ); set_error_status( 1 ); }
    else if( nftw( filename, add_member_lz, 16,
                   cl_opts.dereference ? 0 : FTW_PHYS ) != 0 )
      exit_fail_mt();			// write error or OOM
    else if( cl_opts.solidity == dsolid )	// end of group
      courier.receive_packet( new Ipacket );
    }
--- a/decode.cc
+++ b/decode.cc
@ -1,5 +1,5 @@
 /* Tarlz - Archiver with multimember lzip compression
-   Copyright (C) 2013-2024 Antonio Diaz Diaz.
+   Copyright (C) 2013-2025 Antonio Diaz Diaz.
   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
@ -48,14 +48,18 @@ namespace {
 Resizable_buffer grbuf;
-bool skip_warn( const bool reset = false )	// avoid duplicate warnings
+bool skip_warn( const bool reset = false, const unsigned chksum = 0 )
  {
-  static bool skipping = false;
+  static bool skipping = false;		// avoid duplicate warnings
-  if( reset ) skipping = false;
+  if( reset ) { skipping = false; return false; }
-  else if( !skipping )
+  if( skipping ) return false;
-    { skipping = true; show_error( "Skipping to next header." ); return true; }
+  skipping = true;
-  return false;
+  if( chksum != 0 )
    { if( verbosity < 1 ) show_error( "Corrupt header." );
      else std::fprintf( stderr, "%s: Corrupt header: ustar chksum = %06o\n",
                         program_name, chksum ); }
  show_error( "Skipping to next header." ); return true;
  }
@ -127,20 +131,20 @@ int extract_member( const Cl_options & cl_opts, Archive_reader & ar,
  int outfd = -1;
  if( !show_member_name( extended, header, 1, grbuf ) ) return 1;
  // remove file (or empty dir) before extraction to prevent following links
  std::remove( filename );
  if( !make_dirs( filename ) )
    {
    show_file_error( filename, intdir_msg, errno );
    set_error_status( 1 );
    return skip_member( ar, extended, typeflag );
    }
  // remove file or empty dir before extraction to prevent following links
  std::remove( filename );
  switch( typeflag )
    {
    case tf_regular:
    case tf_hiperf:
-      outfd = open_outstream( filename );
+      outfd = open_outstream( filename, true, 0, false );
      if( outfd < 0 )
        { set_error_status( 1 ); return skip_member( ar, extended, typeflag ); }
      break;
@ -223,7 +227,7 @@ int extract_member( const Cl_options & cl_opts, Archive_reader & ar,
          if( cl_opts.keep_damaged )
            { writeblock( outfd, buf, std::min( rest, (long long)ar.e_size() ) );
              close( outfd ); }
-          else { close( outfd ); std::remove( filename ); }
+          else { close( outfd ); unlink( filename ); }
          }
        if( ar.fatal() ) return ret; else return 0;
        }
@ -386,7 +390,7 @@ bool compare_file_contents( std::string & estr, std::string & ostr,
      const int rd = readblock( infd2, buf2, rsize2 );
      if( rd != rsize2 )
        {
-        if( errno ) format_file_error( estr, filename, "Read error", errno );
+        if( errno ) format_file_error( estr, filename, rd_err_msg, errno );
        else format_file_diff( ostr, filename, "EOF found in file" );
        diff = true;
        }
@ -420,8 +424,8 @@ int decode( const Cl_options & cl_opts )
  const bool c_after_name = c_present &&
                            option_C_after_filename( cl_opts.parser );
  // save current working directory for sequential decoding
-  const int chdir_fd = c_after_name ? open( ".", O_RDONLY | O_DIRECTORY ) : -1;
+  const int cwd_fd = c_after_name ? open( ".", O_RDONLY | O_DIRECTORY ) : -1;
-  if( c_after_name && chdir_fd < 0 )
+  if( c_after_name && cwd_fd < 0 )
    { show_error( "Can't save current working directory", errno ); return 1; }
  if( c_present && !c_after_name )		// execute all -C options
    for( int i = 0; i < cl_opts.parser.arguments(); ++i )
@ -464,8 +468,7 @@ int decode( const Cl_options & cl_opts )
        show_file_error( ad.namep, fv_msg1 );
        retval = 2; break;
        }
-      if( skip_warn() && verbosity >= 2 )
+      skip_warn( false, ustar_chksum( header ) );
        std::fprintf( stderr, "ustar chksum = %07o\n", ustar_chksum( header ) );
      set_error_status( 2 ); continue;
      }
    skip_warn( true );				// reset warning
@ -480,7 +483,7 @@ int decode( const Cl_options & cl_opts )
      if( ret != 0 )
        { show_file_error( ad.namep, ar.e_msg(), ar.e_code() );
          if( ar.fatal() ) { retval = ret; break; }
-          skip_warn(); set_error_status( ret ); }
+          set_error_status( ret ); }
      continue;
      }
    if( typeflag == tf_extended )
@ -492,7 +495,7 @@ int decode( const Cl_options & cl_opts )
      if( ret != 0 )
        { show_file_error( ad.namep, ar.e_msg(), ar.e_code() );
          if( ar.fatal() ) { retval = ret; break; }
-          skip_warn(); extended.reset(); set_error_status( ret ); }
+          extended.reset(); set_error_status( ret ); }
      else if( !extended.crc_present() && cl_opts.missing_crc )
        { show_file_error( ad.namep, miscrc_msg ); retval = 2; break; }
      prev_extended = true; continue;
@ -504,7 +507,7 @@ int decode( const Cl_options & cl_opts )
    try {
      // members without name are skipped except when listing
      if( check_skip_filename( cl_opts, name_pending, extended.path().c_str(),
-          chdir_fd ) ) retval = skip_member( ar, extended, typeflag );
+          cwd_fd ) ) retval = skip_member( ar, extended, typeflag );
      else
        {
        print_removed_prefix( extended.removed_prefix );
--- a/decode.h
+++ b/decode.h
@ -1,5 +1,5 @@
 /* Tarlz - Archiver with multimember lzip compression
-   Copyright (C) 2013-2024 Antonio Diaz Diaz.
+   Copyright (C) 2013-2025 Antonio Diaz Diaz.
   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
@ -16,7 +16,7 @@
 */
 inline bool data_may_follow( const Typeflag typeflag )
-  { return typeflag <= 0 || typeflag >= 7; }
+  { return typeflag == tf_regular || typeflag == tf_hiperf; }
 inline bool uid_gid_in_range( const long long uid, const long long gid )
  { return uid == (long long)( (uid_t)uid ) &&
@ -27,7 +27,7 @@ const char * const cantln_msg = "Can't %slink '%s' to '%s'";
 const char * const mkdir_msg = "Can't create directory";
 const char * const mknod_msg = "Can't create device node";
 const char * const mkfifo_msg = "Can't create FIFO file";
-const char * const uftype_msg = "%s: Unknown file type '%c', skipping.";
+const char * const uftype_msg = "%s: Unknown file type 0x%02X, skipping.";
 const char * const chown_msg = "Can't change file owner";
 mode_t get_umask();
--- a/decode_lz.cc
+++ b/decode_lz.cc
@ -1,5 +1,5 @@
 /* Tarlz - Archiver with multimember lzip compression
-   Copyright (C) 2013-2024 Antonio Diaz Diaz.
+   Copyright (C) 2013-2025 Antonio Diaz Diaz.
   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
@ -41,7 +41,8 @@
 #include "common_mutex.h"
 #include "decode.h"
-/* When a problem is detected by any worker:
+/* Parallel decode does not skip; it exits at the first error.
   When a problem is detected by any worker:
   - the worker requests mastership and returns.
   - the courier discards new packets received or collected.
   - the other workers return.
@ -49,9 +50,9 @@
 namespace {
-const char * const other_msg = "Other worker found an error.";
+const char * const other_msg = "Another worker found an error.";
-/* line is preformatted and newline terminated except for prefix, error.
+/* line is preformatted and newline terminated except for prefix and errors.
   ok with an empty line is a no-op. */
 struct Packet			// member name and metadata or error message
  {
@ -60,7 +61,7 @@ struct Packet			// member name and metadata or error message
  long member_id;	// lzip member containing the header of this tar member
  std::string line;	// member name and metadata ready to print, if any
  Status status;	// diagnostics and errors go to stderr
-  int errcode;		// for error
+  int errcode;		// for errors
  Packet( const long i, const char * const msg, const Status s, const int e )
    : member_id( i ), line( msg ), status( s ), errcode( e ) {}
  };
@ -119,11 +120,12 @@ public:
      { xunlock( &omutex ); return master_id == worker_id; }
    if( error_member_id < 0 || error_member_id > member_id )
      error_member_id = member_id;
-    while( !mastership_granted() && ( worker_id != deliver_id ||
+    while( !mastership_granted() &&
-           !opacket_queues[deliver_id].empty() ) )
+           ( worker_id != deliver_id || !opacket_queues[deliver_id].empty() ) )
      xwait( &check_master, &omutex );
-    if( !mastership_granted() && worker_id == deliver_id &&
+    if( !mastership_granted() &&
-        opacket_queues[deliver_id].empty() )
+        // redundant conditions useful for the compiler
        worker_id == deliver_id && opacket_queues[deliver_id].empty() )
      {
      master_id = worker_id;			// grant mastership
      for( int i = 0; i < num_workers; ++i )	// delete all packets
@ -356,10 +358,9 @@ Trival extract_member_lz( const Cl_options & cl_opts,
    if( !courier.collect_packet( member_id, worker_id, rbuf(), Packet::ok ) )
      return Trival( other_msg, 0, 1 );
    }
-  /* Remove file before extraction to prevent following links.
+  struct stat st;
-     Don't remove an empty dir because other thread may need it. */
+  bool exists = lstat( filename, &st ) == 0;
-  if( typeflag != tf_directory ) std::remove( filename );
+  if( !exists && !make_dirs( filename ) )
  if( !make_dirs( filename ) )
    {
    if( format_file_error( rbuf, filename, intdir_msg, errno ) &&
        !courier.collect_packet( member_id, worker_id, rbuf(), Packet::diag ) )
@ -367,12 +368,16 @@ Trival extract_member_lz( const Cl_options & cl_opts,
    set_error_status( 1 );
    return skip_member_lz( ar, courier, extended, member_id, worker_id, typeflag );
    }
  /* Remove file before extraction to prevent following links.
     Don't remove an empty dir; another thread may need it. */
  if( exists && ( typeflag != tf_directory || !S_ISDIR( st.st_mode ) ) )
    { exists = false; std::remove( filename ); }
  switch( typeflag )
    {
    case tf_regular:
    case tf_hiperf:
-      outfd = open_outstream( filename, true, &rbuf );
+      outfd = open_outstream( filename, true, &rbuf, false );
      if( outfd < 0 )
        {
        if( verbosity >= 0 &&
@ -399,11 +404,6 @@ Trival extract_member_lz( const Cl_options & cl_opts,
        }
      } break;
    case tf_directory:
      {
      struct stat st;
      bool exists = stat( filename, &st ) == 0;
      if( exists && !S_ISDIR( st.st_mode ) )
        { exists = false; std::remove( filename ); }
      if( !exists && mkdir( filename, mode ) != 0 && errno != EEXIST )
        {
        if( format_file_error( rbuf, filename, mkdir_msg, errno ) &&
@ -411,7 +411,7 @@ Trival extract_member_lz( const Cl_options & cl_opts,
          return Trival( other_msg, 0, 1 );
        set_error_status( 1 );
        }
-      } break;
+      break;
    case tf_chardev:
    case tf_blockdev:
      {
@ -483,7 +483,7 @@ Trival extract_member_lz( const Cl_options & cl_opts,
          if( cl_opts.keep_damaged )
            { writeblock( outfd, buf, std::min( rest, (long long)ar.e_size() ) );
              close( outfd ); }
-          else { close( outfd ); std::remove( filename ); }
+          else { close( outfd ); unlink( filename ); }
          }
        return Trival( ar.e_msg(), ar.e_code(), ret );
        }
@ -614,13 +614,18 @@ extern "C" void * dworker( void * arg )
        }
      if( typeflag == tf_extended )
        {
-        const char * msg = 0; int ret = 2;
+        std::vector< std::string > msg_vec;
        const char * msg = 0; int ret = 2; bool good = false;
        if( prev_extended && !cl_opts.permissive ) msg = fv_msg3;
        else if( ( ret = ar.parse_records( extended, header, rbuf, extrec_msg,
-                            cl_opts.permissive ) ) != 0 ) msg = ar.e_msg();
+                     cl_opts.permissive, &msg_vec ) ) != 0 ) msg = ar.e_msg();
        else if( !extended.crc_present() && cl_opts.missing_crc )
          { msg = miscrc_msg; ret = 2; }
-        else { prev_extended = true; continue; }
+        else { prev_extended = true; good = true; }
        for( unsigned j = 0; j < msg_vec.size(); ++j )
          if( !courier.collect_packet( i, worker_id, msg_vec[j].c_str(),
              Packet::diag ) ) { good = false; break; }
        if( good ) continue;
        if( courier.request_mastership( i, worker_id ) )
          courier.collect_packet( i, worker_id, msg, ( ret == 1 ) ?
                                  Packet::error1 : Packet::error2 );
@ -632,13 +637,18 @@ extern "C" void * dworker( void * arg )
      /* Skip members with an empty name in the ustar header. If there is an
         extended header in a previous lzip member, its worker will request
-         mastership. Else the ustar-only unnamed member will be ignored. */
+         mastership and the skip may fail here. Else the ustar-only unnamed
         member will be ignored. */
      std::string rpmsg;			// removed prefix
      Trival trival;
-      if( check_skip_filename( cl_opts, name_pending, extended.path().c_str() ) )
+      if( check_skip_filename( cl_opts, name_pending, extended.path().c_str(),
                               -1, &rpmsg ) )
        trival = skip_member_lz( ar, courier, extended, i, worker_id, typeflag );
      else
        {
-        std::string rpmsg;
+        if( verbosity >= 0 && rpmsg.size() &&
            !courier.collect_packet( i, worker_id, rpmsg.c_str(), Packet::prefix ) )
          { trival = Trival( other_msg, 0, 1 ); goto fatal; }
        if( print_removed_prefix( extended.removed_prefix, &rpmsg ) &&
            !courier.collect_packet( i, worker_id, rpmsg.c_str(), Packet::prefix ) )
          { trival = Trival( other_msg, 0, 1 ); goto fatal; }
@ -667,14 +677,14 @@ done:
  }
-/* Get from courier the processed and sorted packets, and print
+/* Get from courier the processed and sorted packets.
-   the member lines on stdout or the diagnostics and errors on stderr.
+   Print the member lines on stdout and the diagnostics and errors on stderr.
 */
-void muxer( const char * const archive_namep, Packet_courier & courier )
+int muxer( const char * const archive_namep, Packet_courier & courier )
  {
  std::vector< const Packet * > opacket_vector;
  int retval = 0;
-  while( retval == 0 )
+  while( retval == 0 )			// exit loop at first error packet
    {
    courier.deliver_packets( opacket_vector );
    if( opacket_vector.empty() ) break;	// queue is empty. all workers exited
@ -698,7 +708,7 @@ void muxer( const char * const archive_namep, Packet_courier & courier )
    }
  if( retval == 0 && !courier.eoa_found() )	// no worker found EOA blocks
    { show_file_error( archive_namep, end_msg ); retval = 2; }
-  if( retval ) exit_fail_mt( retval );
+  return retval;
  }
 } // end namespace
@ -715,8 +725,6 @@ int decode_lz( const Cl_options & cl_opts, const Archive_descriptor & ad,
  Name_monitor
    name_monitor( ( cl_opts.program_mode == m_extract ) ? num_workers : 0 );
  /* If an error happens after any threads have been started, exit must be
     called before courier goes out of scope. */
  Packet_courier courier( num_workers, out_slots );
  Worker_arg * worker_args = new( std::nothrow ) Worker_arg[num_workers];
@ -737,7 +745,7 @@ int decode_lz( const Cl_options & cl_opts, const Archive_descriptor & ad,
      { show_error( "Can't create worker threads", errcode ); exit_fail_mt(); }
    }
-  muxer( ad.namep, courier );
+  int retval = muxer( ad.namep, courier );
  for( int i = num_workers - 1; i >= 0; --i )
    {
@ -748,9 +756,8 @@ int decode_lz( const Cl_options & cl_opts, const Archive_descriptor & ad,
  delete[] worker_threads;
  delete[] worker_args;
  int retval = 0;
  if( close( ad.infd ) != 0 )
-    { show_file_error( ad.namep, eclosa_msg, errno ); retval = 1; }
+    { show_file_error( ad.namep, eclosa_msg, errno ); set_retval( retval, 1 ); }
  if( retval == 0 )
    for( int i = 0; i < cl_opts.parser.arguments(); ++i )
--- a/delete.cc
+++ b/delete.cc
@ -1,5 +1,5 @@
 /* Tarlz - Archiver with multimember lzip compression
-   Copyright (C) 2013-2024 Antonio Diaz Diaz.
+   Copyright (C) 2013-2025 Antonio Diaz Diaz.
   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
--- a/delete_lz.cc
+++ b/delete_lz.cc
@ -1,5 +1,5 @@
 /* Tarlz - Archiver with multimember lzip compression
-   Copyright (C) 2013-2024 Antonio Diaz Diaz.
+   Copyright (C) 2013-2025 Antonio Diaz Diaz.
   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
--- a/doc/tarlz.1
+++ b/doc/tarlz.1
@ -1,5 +1,5 @@
 .\" DO NOT MODIFY THIS FILE!  It was generated by help2man 1.49.2.
-.TH TARLZ "1" "December 2024" "tarlz 0.26" "User Commands"
+.TH TARLZ "1" "March 2025" "tarlz 0.27" "User Commands"
 .SH NAME
 tarlz \- creates tar archives with multimember lzip compression
 .SH SYNOPSIS
@ -19,7 +19,7 @@ compressed archives.
 .PP
 Keeping the alignment between tar members and lzip members has two
 advantages. It adds an indexed lzip layer on top of the tar archive, making
-it possible to decode the archive safely in parallel. It also minimizes the
+it possible to decode the archive safely in parallel. It also reduces the
 amount of data lost in case of corruption.
 .PP
 The tarlz file format is a safe POSIX\-style backup format. In case of
@ -160,12 +160,12 @@ Report bugs to lzip\-bug@nongnu.org
 .br
 Tarlz home page: http://www.nongnu.org/lzip/tarlz.html
 .SH COPYRIGHT
-Copyright \(co 2024 Antonio Diaz Diaz.
+Copyright \(co 2025 Antonio Diaz Diaz.
 License GPLv2+: GNU GPL version 2 or later <http://gnu.org/licenses/gpl.html>
 .br
 This is free software: you are free to change and redistribute it.
 There is NO WARRANTY, to the extent permitted by law.
-Using lzlib 1.15\-rc1
+Using lzlib 1.15
 Using LZ_API_VERSION = 1015
 .SH "SEE ALSO"
 The full documentation for
--- a/doc/tarlz.info
+++ b/doc/tarlz.info
@ -11,13 +11,14 @@ File: tarlz.info,  Node: Top,  Next: Introduction,  Up: (dir)
 Tarlz Manual
 ************
-This manual is for Tarlz (version 0.26, 7 December 2024).
+This manual is for Tarlz (version 0.27, 28 February 2025).
 * Menu:
 * Introduction::              Purpose and features of tarlz
 * Invoking tarlz::            Command-line interface
 * Argument syntax::           By convention, options start with a hyphen
 * Creating backups safely::   Checking integrity and accuracy of archives
 * Portable character set::    POSIX portable filename character set
 * File format::               Detailed format of the compressed archive
 * Amendments to pax format::  The reasons for the differences with pax
@ -29,7 +30,7 @@ This manual is for Tarlz (version 0.26, 7 December 2024).
 * Concept index::             Index of concepts
-   Copyright (C) 2013-2024 Antonio Diaz Diaz.
+   Copyright (C) 2013-2025 Antonio Diaz Diaz.
   This manual is free documentation: you have unlimited permission to copy,
 distribute, and modify it.
@ -53,7 +54,7 @@ compressed archives.
   Keeping the alignment between tar members and lzip members has two
 advantages. It adds an indexed lzip layer on top of the tar archive, making
-it possible to decode the archive safely in parallel. It also minimizes the
+it possible to decode the archive safely in parallel. It also reduces the
 amount of data lost in case of corruption. Compressing a tar archive with
 plzip may even double the amount of files lost for each lzip member damaged
 because it does not keep the members aligned.
@ -216,7 +217,7 @@ tarlz supports the following operations:
 '-t'
 '--list'
     List the contents of an archive. If FILES are given, list only the
-     FILES given.
+     FILES given. *Note mt-listing::.
 '-x'
 '--extract'
@ -227,20 +228,23 @@ tarlz supports the following operations:
     directories unconditionally before extracting over them. Other than
     that, it does not make any special effort to extract a file over an
     incompatible type of file. For example, extracting a file over a
-     non-empty directory usually fails.
+     non-empty directory usually fails. *Note mt-extraction::.
 '-z'
 '--compress'
     Compress existing POSIX tar archives aligning the lzip members to the
     tar members with choice of granularity ('--bsolid' by default,
-     '--dsolid' works like '--asolid'). Exit with error status 2 if any
+     '--dsolid' works like '--asolid'). Each input archive is compressed to
-     input archive is an empty file. The input archives are kept unchanged.
+     a file with the extension '.lz' added unless the option '--output' is
-     Existing compressed archives are not overwritten. A hyphen '-' used as
+     used. If no archives are specified, or if a hyphen '-' is used as the
-     the name of an input archive reads from standard input and writes to
+     name of an archive, tarlz reads from standard input and writes to
-     standard output (unless the option '--output' is used). Tarlz can be
+     standard output (unless the option '--output' is used). When
-     used as compressor for GNU tar by using a command like
+     '--output' is used, only one input archive can be specified. Exit with
-     'tar -c -Hustar foo | tarlz -z -o foo.tar.lz'. Tarlz can be used as
+     error status 2 if any input archive is an empty file. The input
-     compressor for zupdate (zutils) by using a command like
+     archives are kept unchanged. Existing compressed archives are not
     overwritten. Tarlz can be used as compressor for GNU tar by using a
     command like 'tar -c -Hustar foo | tarlz -z -o foo.tar.lz'. Tarlz can
     be used as compressor for zupdate (zutils) by using a command like
     'zupdate --lz='tarlz -z' foo.tar.gz'. Note that tarlz only works
     reliably on archives without global headers, or with global headers
     whose content can be ignored.
@ -251,11 +255,8 @@ tarlz supports the following operations:
     archive. Unless solid compression is requested, the end-of-archive
     blocks are compressed in a lzip member separated from the preceding
     members and from any nonzero garbage following the end-of-archive
-     blocks. '--compress' implies plzip argument style, not tar style. Each
+     blocks. '--compress' implies plzip argument style, not tar style. '-f'
-     input archive is compressed to a file with the extension '.lz' added
+     can't be used with '--compress'.
     unless the option '--output' is used. When '--output' is used, only
     one input archive can be specified. '-f' can't be used with
     '--compress'.
 '--check-lib'
     Compare the version of lzlib used to compile tarlz with the version
@ -276,7 +277,9 @@ tarlz supports the following options: *Note Argument syntax::.
     Set target size of input data blocks for the option '--bsolid'. *Note
     --bsolid::. Valid values range from 8 KiB to 1 GiB. Default value is
     two times the dictionary size, except for option '-0' where it
-     defaults to 1 MiB. *Note Minimum archive sizes::.
+     defaults to 1 MiB. *Note Minimum archive sizes::. Tarlz does not split
     tar members. If a file is larger than BYTES, tarlz will create a lzip
     member large enough to contain the file.
 '-C DIR'
 '--directory=DIR'
@ -424,12 +427,12 @@ tarlz supports the following options: *Note Argument syntax::.
     group ID.
 '--exclude=PATTERN'
-     Exclude files matching a shell pattern like '*.o'. A file is considered
+     Exclude files matching a shell pattern like '*.o', even if the files
-     to match if any component of the file name matches. For example, '*.o'
+     are specified in the command line. A file is considered to match if any
-     matches 'foo.o', 'foo.o/bar' and 'foo/bar.o'. If PATTERN contains a
+     component of the file name matches. For example, '*.o' matches
-     '/', it matches a corresponding '/' in the file name. For example,
+     'foo.o', 'foo.o/bar' and 'foo/bar.o'. If PATTERN contains a '/', it
-     'foo/*.o' matches 'foo/bar.o'. Multiple '--exclude' options can be
+     matches a corresponding '/' in the file name. For example, 'foo/*.o'
-     specified.
+     matches 'foo/bar.o'. Multiple '--exclude' options can be specified.
 '--ignore-ids'
     Make '--diff' ignore differences in owner and group IDs. This option is
@ -486,10 +489,10 @@ tarlz supports the following options: *Note Argument syntax::.
     During archive creation, warn if any file being archived has a
     modification time newer than the archive creation time. This option
     may slow archive creation somewhat because it makes an extra call to
-     'stat' after archiving each file, but it guarantees that file contents
+     'stat' after archiving each file, but it nearly guarantees that file
-     were not modified during the creation of the archive. Note that the
+     contents were not modified during the creation of the archive. Note
-     file must be at least one second newer than the archive for it to be
+     that the file must be at least one second newer than the archive for
-     detected as newer.
+     it to be detected as newer.
   Exit status: 0 for a normal exit, 1 for environmental problems (file not
@ -498,7 +501,7 @@ indicate a corrupt or invalid input file, 3 for an internal consistency
 error (e.g., bug) which caused tarlz to panic.
-File: tarlz.info,  Node: Argument syntax,  Next: Portable character set,  Prev: Invoking tarlz,  Up: Top
+File: tarlz.info,  Node: Argument syntax,  Next: Creating backups safely,  Prev: Invoking tarlz,  Up: Top
 3 Syntax of command-line arguments
 **********************************
@ -541,9 +544,55 @@ GNU adds "long options" to these conventions:
     Thus, '--foo bar' and '--foo=bar' are equivalent.
-File: tarlz.info,  Node: Portable character set,  Next: File format,  Prev: Argument syntax,  Up: Top
+File: tarlz.info,  Node: Creating backups safely,  Next: Portable character set,  Prev: Argument syntax,  Up: Top
-4 POSIX portable filename character set
+4 Checking the integrity and accuracy of tar.lz archives
 ********************************************************
 Uncompressed tar archives do not offer any integrity checking for the files
 they store. The pax format even fails to offer integrity checking for some
 of the metadata. *Note crc32::. The integrity checking of tar archives is
 usually provided by a compression layer or by an external hash.
   Lzip compression provides safe integrity checking to tar archives. But it
 does not matter how safe is the archiving format if the archive is created
 corrupt because of a concurrent modification of the files being archived, a
 faulty RAM, or a bug in the archiving tool. The only way of guaranteeing
 that a backup archive is correct is to check its integrity and accuracy
 after creating it.
   Testing the integrity of the archive with 'lzip -tv' guarantees that the
 compression layer of the archive is valid, but it does not guarantee that
 the tar layer is valid nor that the files in the archive match the files in
 the file system. For example, if the RAM is faulty and a bit flip happens
 in the input buffer before tarlz compresses it, the archive will not match
 the files. It is safer to check the archive with 'tarlz -d' just after
 creation because it checks the compression layer and the tar layer, and it
 compares the files in the archive with the files in the file system:
     tarlz -cf archive.tar.lz somedir         # create the archive
     tarlz -df archive.tar.lz                 # check the archive
   Once the integrity and accuracy of an archive have been verified as in
 the example above, they can be verified again anywhere at any time with
 'tarlz -t -n0'. It is important to disable multi-threading with '-n0'
 because multi-threaded listing does not detect corruption in the tar member
 data of multimember archives: *Note mt-listing::.
     tarlz -t -n0 -f archive.tar.lz > /dev/null
   'lzip -tv' checks the integrity of the compression layer, and therefore
 the integrity and accuracy of any archive created and verified as explained
 above. This test is reliable for solidly compressed archives, but it does
 not detect a truncated multimember archive if the truncation happens just
 at a member boundary:
     lzip -tv archive.tar.lz
 File: tarlz.info,  Node: Portable character set,  Next: File format,  Prev: Creating backups safely,  Up: Top
 5 POSIX portable filename character set
 ***************************************
 The set of characters from which portable file names are constructed.
@ -561,7 +610,7 @@ names use only the portable character set without spaces added.
 File: tarlz.info,  Node: File format,  Next: Amendments to pax format,  Prev: Portable character set,  Up: Top
-5 File format
+6 File format
 *************
 In the diagram below, a box like this:
@ -632,7 +681,7 @@ tar.lz
 |     member    |                      member                     | member |
 +===============+=================================================+========+
-5.1 Pax header block
+6.1 Pax header block
 ====================
 The pax header block is identical to the ustar header block described below
@ -676,7 +725,7 @@ space, equal-sign, and newline.
     previously archived. This record overrides the field 'linkname' in the
     following ustar header block. The following ustar header block
     determines the type of link created. If typeflag of the following
-     header block is 1, a hard link is created. If typeflag is 2, a
+     header block is '1', a hard link is created. If typeflag is '2', a
     symbolic link is created and the linkpath value is used as the
     contents of the symbolic link. The linkpath record is created only for
     links with a link name that does not fit in the space provided by the
@ -716,17 +765,17 @@ space, equal-sign, and newline.
     CRC32-C (Castagnoli) of the extended header data excluding the 8 bytes
     representing the CRC <value> itself. The <value> is represented as 8
     hexadecimal digits in big endian order, '22 GNU.crc32=00000000\n'. The
-     keyword of the CRC record is protected by the CRC to guarantee that
+     option '--missing-crc' guarantees that corruption is always detected
-     corruption is always detected when using '--missing-crc' (except in
+     (except in case of CRC collision). A CRC was chosen because a checksum
-     case of CRC collision). A CRC was chosen because a checksum is too
+     is too weak for a potentially large list of variable sized records. A
     weak for a potentially large list of variable sized records. A
     checksum can't detect simple errors like the swapping of two bytes.
     *Note --missing-crc::.
   At verbosity level 1 or higher tarlz prints a diagnostic for each unknown
 extended header keyword found in an archive, once per keyword.
-5.2 Ustar header block
+6.2 Ustar header block
 ======================
 The ustar header block has a length of 512 bytes and is structured as shown
@ -750,6 +799,7 @@ gname        297      32
 devmajor     329      8
 devminor     337      8
 prefix       345      155
 padding      500      12
   All characters in the header block are coded using the ISO/IEC 646:1991
 (ASCII) standard, except in fields storing names for files, users, and
@ -839,7 +889,7 @@ file archived:
 ''7''
     Reserved to represent a file to which an implementation has associated
     some high-performance attribute (contiguous file). Tarlz treats this
-     type of file as a regular file (type 0).
+     type of file as a regular file (type '0').
   The field 'magic' contains the ASCII null-terminated string "ustar". The
@ -848,13 +898,13 @@ field 'version' contains the characters "00" (0x30,0x30). The fields
 characters in the array contain non-null characters including the last
 character. Each numeric field contains a leading space- or zero-filled,
 optionally null-terminated octal number using digits from the ISO/IEC
-646:1991 (ASCII) standard. Tarlz is able to decode numeric fields 1 byte
+646:1991 (ASCII) standard. Tarlz is able to decode numeric fields one byte
 longer than standard ustar by not requiring a terminating null character.
 File: tarlz.info,  Node: Amendments to pax format,  Next: Program design,  Prev: File format,  Up: Top
-6 The reasons for the differences with pax
+7 The reasons for the differences with pax
 ******************************************
 Tarlz creates safe archives that allow the reliable detection of invalid or
@ -865,7 +915,7 @@ achieve this goal and avoid some other flaws in the pax format, tarlz makes
 some changes to the variant of the pax format that it uses. This chapter
 describes these changes and the concrete reasons to implement them.
-6.1 Add a CRC of the extended records
+7.1 Add a CRC of the extended records
 =====================================
 The POSIX pax format has a serious flaw. The metadata stored in pax extended
@ -892,7 +942,7 @@ place.
 Redundancy Check (CRC) in a way compatible with standard tar tools. *Note
 key_crc32::.
-6.2 Remove flawed backward compatibility
+7.2 Remove flawed backward compatibility
 ========================================
 In order to allow the extraction of pax archives by a tar utility conforming
@ -925,7 +975,7 @@ trying to extract the file or link. This also makes easier during parallel
 decoding the detection of a tar member split between two lzip members at
 the boundary between the extended header and the ustar header.
-6.3 As simple as possible (but not simpler)
+7.3 As simple as possible (but not simpler)
 ===========================================
 The tarlz format is mainly ustar. Extended pax headers are used only when
@ -940,7 +990,7 @@ corruption.
 ignored. Some operations may not behave as expected if the archive contains
 global headers.
-6.4 Improve reproducibility
+7.4 Improve reproducibility
 ===========================
 Pax includes by default the process ID of the pax process in the ustar name
@ -952,7 +1002,7 @@ extended records, making it easier to produce reproducible archives.
 ten; '99<97_bytes>' or '100<97_bytes>'. Tarlz minimizes the length of the
 record and always produces a length of x-1 in these cases.
-6.5 No data in hard links
+7.5 No data in hard links
 =========================
 Tarlz does not allow data in hard link members. The data (if any) must be in
@ -961,27 +1011,26 @@ the names of a file are stored as hard links, the type of the file is lost.
 Not allowing data in hard links also prevents invalid actions like
 extracting file data for a hard link to a symbolic link or to a directory.
-6.6 Avoid misconversions to/from UTF-8
+7.6 Avoid misconversions to/from UTF-8
 ======================================
 There is no portable way to tell what charset a text string is coded into.
 Therefore, tarlz stores all fields representing text strings unmodified,
 without conversion to UTF-8 nor any other transformation. This prevents
-accidental double UTF-8 conversions. If the need arises this behavior will
+accidental double UTF-8 conversions.
 be adjusted with a command-line option in the future.
 File: tarlz.info,  Node: Program design,  Next: Multi-threaded decoding,  Prev: Amendments to pax format,  Up: Top
-7 Internal structure of tarlz
+8 Internal structure of tarlz
 *****************************
 The parts of tarlz related to sequential processing of the archive are more
 or less similar to any other tar and won't be described here. The
-interesting parts described here are those related to Multi-threaded
+interesting parts described here are those related to multi-threaded
 processing.
-   The structure of the part of tarlz performing Multi-threaded archive
+   The structure of the part of tarlz performing multi-threaded archive
 creation is somewhat similar to that of plzip with the added complication
 of the solidity levels. *Note Program design: (plzip)Program design. A
 grouper thread and several worker threads are created, acting the main
@ -1053,7 +1102,7 @@ error be avoided.
 File: tarlz.info,  Node: Multi-threaded decoding,  Next: Minimum archive sizes,  Prev: Program design,  Up: Top
-8 Limitations of parallel tar decoding
+9 Limitations of parallel tar decoding
 **************************************
 Safely decoding a tar archive in parallel is only possible if one decodes
@ -1093,11 +1142,14 @@ tar.lz archives, keeping backwards compatibility. If tarlz finds a member
 misalignment during multi-threaded decoding, it switches to single-threaded
 mode and continues decoding the archive.
-   If the files in the archive are large, multi-threaded '--list' on a
+9.1 Multi-threaded listing
-regular (seekable) tar.lz archive can be hundreds of times faster than
+==========================
-sequential '--list' because, in addition to using several processors, it
+
-only needs to decompress part of each lzip member. See the following
+If the files in the archive are large, multi-threaded '--list' on a regular
-example listing the Silesia corpus on a dual core machine:
+(seekable) tar.lz archive can be hundreds of times faster than sequential
 '--list' because, in addition to using several processors, it only needs to
 decompress part of each lzip member. See the following example listing the
 Silesia corpus on a dual core machine:
     tarlz -9 --no-solid -cf silesia.tar.lz silesia
     time lzip -cd silesia.tar.lz | tar -tf -            (5.032s)
@ -1106,10 +1158,12 @@ example listing the Silesia corpus on a dual core machine:
   On the other hand, multi-threaded '--list' won't detect corruption in
 the tar member data because it only decodes the part of each lzip member
-corresponding to the tar member header. This is another reason why the tar
+corresponding to the tar member header. Partial decoding of a lzip member
-headers must provide their own integrity checking.
+can't guarantee the integrity of the data decoded. This is another reason
 why the tar headers (including the extended records) must provide their own
 integrity checking.
-8.1 Limitations of multi-threaded extraction
+9.2 Limitations of multi-threaded extraction
 ============================================
 Multi-threaded extraction may produce different output than single-threaded
@ -1139,8 +1193,8 @@ links to.
 File: tarlz.info,  Node: Minimum archive sizes,  Next: Examples,  Prev: Multi-threaded decoding,  Up: Top
-9 Minimum archive sizes required for multi-threaded block compression
+10 Minimum archive sizes required for multi-threaded block compression
-*********************************************************************
+**********************************************************************
 When creating or appending to a compressed archive using multi-threaded
 block compression, tarlz puts tar members together in blocks and compresses
@ -1177,7 +1231,7 @@ Level
 File: tarlz.info,  Node: Examples,  Next: Problems,  Prev: Minimum archive sizes,  Up: Top
-10 A small tutorial with examples
+11 A small tutorial with examples
 *********************************
 Example 1: Create a multimember compressed archive 'archive.tar.lz'
@ -1233,10 +1287,12 @@ other members can still be extracted).
     tarlz -z --no-solid archive.tar
-Example 10: Compress the archive 'archive.tar' and write the output to
+Example 10: Recompress the archive 'archive.tar.lz' with different
-'foo.tar.lz'.
+solidity, write the output to 'archive-ns.tar.lz', and compare both
 archives.
-     tarlz -z -o foo.tar.lz archive.tar
+     lzip -cd archive.tar.lz | tarlz -9z --no-solid -o archive-ns.tar.lz
     zcmp archive.tar.lz archive-ns.tar.lz
 Example 11: Concatenate and compress two archives 'archive1.tar' and
 'archive2.tar', and write the output to 'foo.tar.lz'.
@ -1246,7 +1302,7 @@ Example 11: Concatenate and compress two archives 'archive1.tar' and
 File: tarlz.info,  Node: Problems,  Next: Concept index,  Prev: Examples,  Up: Top
-11 Reporting bugs
+12 Reporting bugs
 *****************
 There are probably bugs in tarlz. There are certainly errors and omissions
@ -1270,6 +1326,7 @@ Concept index
 * Amendments to pax format:              Amendments to pax format.  (line 6)
 * argument syntax:                       Argument syntax.           (line 6)
 * bugs:                                  Problems.                  (line 6)
 * creating backups:                      Creating backups safely.   (line 6)
 * examples:                              Examples.                  (line 6)
 * file format:                           File format.               (line 6)
 * getting help:                          Problems.                  (line 6)
@ -1287,26 +1344,29 @@ Concept index
 Tag Table:
 Node: Top216
-Node: Introduction1281
+Node: Introduction1356
-Node: Invoking tarlz4106
+Node: Invoking tarlz4179
-Ref: --data-size13109
+Ref: --data-size13265
-Ref: --bsolid17626
+Ref: --bsolid17924
-Node: Argument syntax23539
+Ref: --missing-crc21532
-Node: Portable character set25314
+Node: Argument syntax23897
-Node: File format25958
+Node: Creating backups safely25673
-Ref: key_crc3233001
+Node: Portable character set28057
-Ref: ustar-uid-gid36305
+Node: File format28709
-Ref: ustar-mtime37112
+Ref: key_crc3235756
-Node: Amendments to pax format39115
+Ref: ustar-uid-gid39052
-Ref: crc3239823
+Ref: ustar-mtime39859
-Ref: flawed-compat41134
+Node: Amendments to pax format41866
-Node: Program design45211
+Ref: crc3242574
-Node: Multi-threaded decoding49138
+Ref: flawed-compat43885
-Ref: mt-extraction52407
+Node: Program design47870
-Node: Minimum archive sizes53713
+Node: Multi-threaded decoding51797
-Node: Examples55840
+Ref: mt-listing54198
-Node: Problems58199
+Ref: mt-extraction55236
-Node: Concept index58754
+Node: Minimum archive sizes56542
 Node: Examples58671
 Node: Problems61166
 Node: Concept index61721
 End Tag Table
--- a/doc/tarlz.texi
+++ b/doc/tarlz.texi
@ -6,8 +6,8 @@
@finalout
@c %**end of header
-@set UPDATED 7 December 2024
+@set UPDATED 28 February 2025
-@set VERSION 0.26
+@set VERSION 0.27
@dircategory Archiving
@direntry
@ -39,6 +39,7 @@ This manual is for Tarlz (version @value{VERSION}, @value{UPDATED}).
 * Introduction::              Purpose and features of tarlz
 * Invoking tarlz::            Command-line interface
 * Argument syntax::           By convention, options start with a hyphen
 * Creating backups safely::   Checking integrity and accuracy of archives
 * Portable character set::    POSIX portable filename character set
 * File format::               Detailed format of the compressed archive
 * Amendments to pax format::  The reasons for the differences with pax
@ -51,7 +52,7 @@ This manual is for Tarlz (version @value{VERSION}, @value{UPDATED}).
@end menu
@sp 1
-Copyright @copyright{} 2013-2024 Antonio Diaz Diaz.
+Copyright @copyright{} 2013-2025 Antonio Diaz Diaz.
 This manual is free documentation: you have unlimited permission to copy,
 distribute, and modify it.
@ -76,7 +77,7 @@ compressed archives.
 Keeping the alignment between tar members and lzip members has two
 advantages. It adds an indexed lzip layer on top of the tar archive, making
-it possible to decode the archive safely in parallel. It also minimizes the
+it possible to decode the archive safely in parallel. It also reduces the
 amount of data lost in case of corruption. Compressing a tar archive with
 plzip may even double the amount of files lost for each lzip member damaged
 because it does not keep the members aligned.
@ -254,7 +255,7 @@ during multi-threaded extraction. @xref{mt-extraction}.
@item -t
@itemx --list
 List the contents of an archive. If @var{files} are given, list only the
-@var{files} given.
+@var{files} given. @xref{mt-listing}.
@item -x
@itemx --extract
@ -265,20 +266,23 @@ directory without extracting the files under it, use
 empty directories unconditionally before extracting over them. Other than
 that, it does not make any special effort to extract a file over an
 incompatible type of file. For example, extracting a file over a non-empty
-directory usually fails.
+directory usually fails. @xref{mt-extraction}.
@item -z
@itemx --compress
 Compress existing POSIX tar archives aligning the lzip members to the tar
 members with choice of granularity (@option{--bsolid} by default,
-@option{--dsolid} works like @option{--asolid}). Exit with error status 2 if
+@option{--dsolid} works like @option{--asolid}). Each input archive is
-any input archive is an empty file. The input archives are kept unchanged.
+compressed to a file with the extension @file{.lz} added unless the option
-Existing compressed archives are not overwritten. A hyphen @samp{-} used as
+@option{--output} is used. If no archives are specified, or if a hyphen
-the name of an input archive reads from standard input and writes to
+@samp{-} is used as the name of an archive, tarlz reads from standard input
-standard output (unless the option @option{--output} is used). Tarlz can be
+and writes to standard output (unless the option @option{--output} is used).
-used as compressor for GNU tar by using a command like
+When @option{--output} is used, only one input archive can be specified.
-@w{@samp{tar -c -Hustar foo | tarlz -z -o foo.tar.lz}}. Tarlz can be used as
+Exit with error status 2 if any input archive is an empty file. The input
-compressor for zupdate (zutils) by using a command like
+archives are kept unchanged. Existing compressed archives are not
 overwritten. Tarlz can be used as compressor for GNU tar by using a command
 like @w{@samp{tar -c -Hustar foo | tarlz -z -o foo.tar.lz}}. Tarlz can be
 used as compressor for zupdate (zutils) by using a command like
@w{@samp{zupdate --lz='tarlz -z' foo.tar.gz}}. Note that tarlz only works
 reliably on archives without global headers, or with global headers whose
 content can be ignored.
@ -289,10 +293,8 @@ block is found, and then compresses the rest of the archive. Unless solid
 compression is requested, the end-of-archive blocks are compressed in a lzip
 member separated from the preceding members and from any nonzero garbage
 following the end-of-archive blocks. @option{--compress} implies plzip
-argument style, not tar style. Each input archive is compressed to a file
+argument style, not tar style. @option{-f} can't be used with
-with the extension @file{.lz} added unless the option @option{--output} is
+@option{--compress}.
 used. When @option{--output} is used, only one input archive can be specified.
@option{-f} can't be used with @option{--compress}.
@item --check-lib
 Compare the
@ -319,8 +321,10 @@ tarlz supports the following options: @xref{Argument syntax}.
@itemx --data-size=@var{bytes}
 Set target size of input data blocks for the option @option{--bsolid}.
@xref{--bsolid}. Valid values range from @w{8 KiB} to @w{1 GiB}. Default
-value is two times the dictionary size, except for option @option{-0} where it
+value is two times the dictionary size, except for option @option{-0} where
-defaults to @w{1 MiB}. @xref{Minimum archive sizes}.
+it defaults to @w{1 MiB}. @xref{Minimum archive sizes}. Tarlz does not split
 tar members. If a file is larger than @var{bytes}, tarlz will create a lzip
 member large enough to contain the file.
@item -C @var{dir}
@itemx --directory=@var{dir}
@ -465,12 +469,13 @@ If @var{group} is not a valid group name, it is decoded as a decimal numeric
 group ID.
@item --exclude=@var{pattern}
-Exclude files matching a shell pattern like @file{*.o}. A file is considered
+Exclude files matching a shell pattern like @file{*.o}, even if the files
-to match if any component of the file name matches. For example, @file{*.o}
+are specified in the command line. A file is considered to match if any
-matches @file{foo.o}, @file{foo.o/bar} and @file{foo/bar.o}. If
+component of the file name matches. For example, @file{*.o} matches
-@var{pattern} contains a @samp{/}, it matches a corresponding @samp{/} in
+@file{foo.o}, @file{foo.o/bar} and @file{foo/bar.o}. If @var{pattern}
-the file name. For example, @file{foo/*.o} matches @file{foo/bar.o}.
+contains a @samp{/}, it matches a corresponding @samp{/} in the file name.
-Multiple @option{--exclude} options can be specified.
+For example, @file{foo/*.o} matches @file{foo/bar.o}. Multiple
@option{--exclude} options can be specified.
@item --ignore-ids
 Make @option{--diff} ignore differences in owner and group IDs. This option is
@ -493,6 +498,7 @@ recover as much data as possible from each damaged member. It is recommended
 to run tarlz in single-threaded mode (@option{--threads=0}) when using this
 option.
@anchor{--missing-crc}
@item --missing-crc
 Exit with error status 2 if the CRC of the extended records is missing. When
 this option is used, tarlz detects any corruption in the extended records
@ -525,9 +531,9 @@ values range from 1 to 1024. The default value is 64.
 During archive creation, warn if any file being archived has a modification
 time newer than the archive creation time. This option may slow archive
 creation somewhat because it makes an extra call to @samp{stat} after
-archiving each file, but it guarantees that file contents were not modified
+archiving each file, but it nearly guarantees that file contents were not
-during the creation of the archive. Note that the file must be at least one
+modified during the creation of the archive. Note that the file must be at
-second newer than the archive for it to be detected as newer.
+least one second newer than the archive for it to be detected as newer.
@ignore
@item --permissive
@ -591,6 +597,58 @@ Thus, @w{@option{--foo bar}} and @option{--foo=bar} are equivalent.
@end itemize
@node Creating backups safely
@chapter Checking the integrity and accuracy of tar.lz archives
@cindex creating backups
 Uncompressed tar archives do not offer any integrity checking for the files
 they store. The pax format even fails to offer integrity checking for some
 of the metadata. @xref{crc32}. The integrity checking of tar archives is
 usually provided by a compression layer or by an external hash.
 Lzip compression provides safe integrity checking to tar archives. But it
 does not matter how safe is the archiving format if the archive is created
 corrupt because of a concurrent modification of the files being archived, a
 faulty RAM, or a bug in the archiving tool. The only way of guaranteeing
 that a backup archive is correct is to check its integrity and accuracy
 after creating it.
 Testing the integrity of the archive with @w{@samp{lzip -tv}} guarantees
 that the compression layer of the archive is valid, but it does not
 guarantee that the tar layer is valid nor that the files in the archive
 match the files in the file system. For example, if the RAM is faulty and a
 bit flip happens in the input buffer before tarlz compresses it, the archive
 will not match the files. It is safer to check the archive with
@w{@samp{tarlz -d}} just after creation because it checks the compression
 layer and the tar layer, and it compares the files in the archive with the
 files in the file system:
@example
 tarlz -cf archive.tar.lz somedir         # create the archive
 tarlz -df archive.tar.lz                 # check the archive
@end example
 Once the integrity and accuracy of an archive have been verified as in the
 example above, they can be verified again anywhere at any time with
@w{@samp{tarlz -t -n0}}. It is important to disable multi-threading with
@option{-n0} because multi-threaded listing does not detect corruption in
 the tar member data of multimember archives: @xref{mt-listing}.
@example
 tarlz -t -n0 -f archive.tar.lz > /dev/null
@end example
@w{@samp{lzip -tv}} checks the integrity of the compression layer, and
 therefore the integrity and accuracy of any archive created and verified as
 explained above. This test is reliable for solidly compressed archives, but
 it does not detect a truncated multimember archive if the truncation happens
 just at a member boundary:
@example
 lzip -tv archive.tar.lz
@end example
@node Portable character set
@chapter POSIX portable filename character set
@cindex portable character set
@ -641,7 +699,7 @@ are not allowed in multimember files.
 Each lzip member contains one or more tar members in a simplified POSIX pax
 interchange format. The only pax typeflag value supported by tarlz (in
-addition to the typeflag values defined by the ustar format) is @samp{x}.
+addition to the typeflag values defined by the ustar format) is 'x'.
 The pax format is an extension on top of the ustar format that removes the
 size limitations of the ustar format.
@ -654,7 +712,7 @@ An optional extended header block followed by one or more blocks that
 contain the extended header records as if they were the contents of a file;
 i.e., the extended header records are included as the data for this header
 block. This header block is of the form described in pax header block, with
-a typeflag value of @samp{x}.
+a typeflag value of 'x'.
@item
 A header block in ustar format that describes the file. Any fields defined
@ -713,7 +771,7 @@ An extended header just before the end-of-archive blocks.
@section Pax header block
 The pax header block is identical to the ustar header block described below
-except that the typeflag has the value @samp{x} (extended). The field
+except that the typeflag has the value 'x' (extended). The field
@samp{size} is the size of the extended header data in bytes. Most other
 fields in the pax header block are zeroed on archive creation to prevent
 trouble if the archive is read by a ustar tool, and are ignored by tarlz on
@ -752,8 +810,8 @@ greater than 2_097_151 @w{(octal 7_777_777)}. @xref{ustar-uid-gid}.
 The file name of a link being created to another file, of any type,
 previously archived. This record overrides the field @samp{linkname} in the
 following ustar header block. The following ustar header block determines
-the type of link created. If typeflag of the following header block is 1, a
+the type of link created. If typeflag of the following header block is '1', a
-hard link is created. If typeflag is 2, a symbolic link is created and the
+hard link is created. If typeflag is '2', a symbolic link is created and the
 linkpath value is used as the contents of the symbolic link. The linkpath
 record is created only for links with a link name that does not fit in the
 space provided by the ustar header.
@ -789,13 +847,12 @@ greater than 2_097_151 @w{(octal 7_777_777)}. @xref{ustar-uid-gid}.
@item GNU.crc32
 CRC32-C (Castagnoli) of the extended header data excluding the 8 bytes
 representing the CRC <value> itself. The <value> is represented as 8
-hexadecimal digits in big endian order,
+hexadecimal digits in big endian order, @w{@samp{22 GNU.crc32=00000000\n}}.
-@w{@samp{22 GNU.crc32=00000000\n}}. The keyword of the CRC record is
+The option @option{--missing-crc} guarantees that corruption is always
-protected by the CRC to guarantee that corruption is always detected when
+detected (except in case of CRC collision). A CRC was chosen because a
-using @option{--missing-crc} (except in case of CRC collision). A CRC was
+checksum is too weak for a potentially large list of variable sized records.
-chosen because a checksum is too weak for a potentially large list of
+A checksum can't detect simple errors like the swapping of two bytes.
-variable sized records. A checksum can't detect simple errors like the
+@xref{--missing-crc}.
 swapping of two bytes.
@end table
@ -825,6 +882,7 @@ shown in the following table. All lengths and offsets are in decimal:
@item devmajor @tab 329 @tab   8
@item devminor @tab 337 @tab   8
@item prefix   @tab 345 @tab 155
@item padding  @tab 500 @tab  12
@end multitable
 All characters in the header block are coded using the ISO/IEC 646:1991
@ -919,7 +977,7 @@ FIFO special file.
@item '7'
 Reserved to represent a file to which an implementation has associated some
 high-performance attribute (contiguous file). Tarlz treats this type of file
-as a regular file (type 0).
+as a regular file (type '0').
@end table
@ -930,8 +988,8 @@ except when all characters in the array contain non-null characters
 including the last character. Each numeric field contains a leading space-
 or zero-filled, optionally null-terminated octal number using digits from
 the ISO/IEC 646:1991 (ASCII) standard. Tarlz is able to decode numeric
-fields 1 byte longer than standard ustar by not requiring a terminating null
+fields one byte longer than standard ustar by not requiring a terminating
-character.
+null character.
@node Amendments to pax format
@ -1044,8 +1102,7 @@ extracting file data for a hard link to a symbolic link or to a directory.
 There is no portable way to tell what charset a text string is coded into.
 Therefore, tarlz stores all fields representing text strings unmodified,
 without conversion to UTF-8 nor any other transformation. This prevents
-accidental double UTF-8 conversions. If the need arises this behavior will
+accidental double UTF-8 conversions.
 be adjusted with a command-line option in the future.
@node Program design
@ -1054,12 +1111,12 @@ be adjusted with a command-line option in the future.
 The parts of tarlz related to sequential processing of the archive are more
 or less similar to any other tar and won't be described here. The interesting
-parts described here are those related to Multi-threaded processing.
+parts described here are those related to multi-threaded processing.
-The structure of the part of tarlz performing Multi-threaded archive
+The structure of the part of tarlz performing multi-threaded archive
 creation is somewhat similar to that of
-@uref{http://www.nongnu.org/lzip/plzip.html#Program-design,,plzip} with the
+@uref{http://www.nongnu.org/lzip/manual/plzip_manual.html#Program-design,,plzip}
-added complication of the solidity levels.
+with the added complication of the solidity levels.
@ifnothtml
@xref{Program design,,,plzip}.
@end ifnothtml
@ -1174,6 +1231,9 @@ tar.lz archives, keeping backwards compatibility. If tarlz finds a member
 misalignment during multi-threaded decoding, it switches to single-threaded
 mode and continues decoding the archive.
@anchor{mt-listing}
@section Multi-threaded listing
 If the files in the archive are large, multi-threaded @option{--list} on a
 regular (seekable) tar.lz archive can be hundreds of times faster than
 sequential @option{--list} because, in addition to using several processors,
@ -1189,8 +1249,10 @@ time tarlz -tf silesia.tar.lz                       (0.020s)
 On the other hand, multi-threaded @option{--list} won't detect corruption in
 the tar member data because it only decodes the part of each lzip member
-corresponding to the tar member header. This is another reason why the tar
+corresponding to the tar member header. Partial decoding of a lzip member
-headers must provide their own integrity checking.
+can't guarantee the integrity of the data decoded. This is another reason
 why the tar headers (including the extended records) must provide their own
 integrity checking.
@anchor{mt-extraction}
@section Limitations of multi-threaded extraction
@ -1344,11 +1406,13 @@ tarlz -z --no-solid archive.tar
@end example
@noindent
-Example 10: Compress the archive @file{archive.tar} and write the output to
+Example 10: Recompress the archive @file{archive.tar.lz} with different
-@file{foo.tar.lz}.
+solidity, write the output to @file{archive-ns.tar.lz}, and compare both
 archives.
@example
-tarlz -z -o foo.tar.lz archive.tar
+lzip -cd archive.tar.lz | tarlz -9z --no-solid -o archive-ns.tar.lz
 zcmp archive.tar.lz archive-ns.tar.lz
@end example
@noindent
--- a/exclude.cc
+++ b/exclude.cc
@ -1,5 +1,5 @@
 /* Tarlz - Archiver with multimember lzip compression
-   Copyright (C) 2013-2024 Antonio Diaz Diaz.
+   Copyright (C) 2013-2025 Antonio Diaz Diaz.
   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
--- a/extended.cc
+++ b/extended.cc
@ -1,5 +1,5 @@
 /* Tarlz - Archiver with multimember lzip compression
-   Copyright (C) 2013-2024 Antonio Diaz Diaz.
+   Copyright (C) 2013-2025 Antonio Diaz Diaz.
   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
@ -22,6 +22,7 @@
 #include <cstdio>
 #include "tarlz.h"
 #include "common_mutex.h"
 const CRC32 crc32c( true );
@ -58,9 +59,9 @@ long long parse_decimal( const char * const ptr, const char ** const tailp,
  }
-uint32_t parse_record_crc( const char * const ptr )
+unsigned parse_record_crc( const char * const ptr )
  {
-  uint32_t crc = 0;
+  unsigned crc = 0;
  for( int i = 0; i < 8; ++i )
    {
    crc <<= 4;
@ -201,16 +202,25 @@ void Extended::calculate_sizes() const
 // print a diagnostic for each unknown keyword once per keyword
-void Extended::unknown_keyword( const char * const buf, const int size ) const
+void Extended::unknown_keyword( const char * const buf, const int size,
                        std::vector< std::string > * const msg_vecp ) const
  {
  // prevent two threads from modifying the list of keywords at the same time
  static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
  int eq_pos = 0;				// position of '=' in buf
  while( eq_pos < size && buf[eq_pos] != '=' ) ++eq_pos;
  const std::string keyword( buf, eq_pos );
  xlock( &mutex );
  for( unsigned i = 0; i < unknown_keywords.size(); ++i )
-    if( keyword == unknown_keywords[i] ) return;
+    if( keyword == unknown_keywords[i] ) { xunlock( &mutex ); return; }
  unknown_keywords.push_back( keyword );
-  print_error( 0, "Ignoring unknown extended header keyword '%s'",
+  xunlock( &mutex );
-               keyword.c_str() );
+  const char * str = "Ignoring unknown extended header keyword '%s'";
  if( !msg_vecp ) print_error( 0, str, keyword.c_str() );
  else
    { msg_vecp->push_back( std::string() );
      format_error( msg_vecp->back(), 0, str, keyword.c_str() ); }
  }
@ -281,7 +291,8 @@ const char * Extended::full_size_error() const
 bool Extended::parse( const char * const buf, const int edsize,
-                      const bool permissive )
+                      const bool permissive,
                      std::vector< std::string > * const msg_vecp )
  {
  reset(); full_size_ = -4;			// invalidate cached sizes
  for( int pos = 0; pos < edsize; )		// parse records
@ -348,18 +359,22 @@ bool Extended::parse( const char * const buf, const int edsize,
      if( crc_present_ && !permissive ) return false;
      if( rsize != (int)crc_record.size() ) return false;
      crc_present_ = true;
-      const uint32_t stored_crc = parse_record_crc( tail + 10 );
+      const unsigned stored_crc = parse_record_crc( tail + 10 );
-      const uint32_t computed_crc =
+      const unsigned computed_crc =
        crc32c.windowed_crc( (const uint8_t *)buf, pos + rsize - 9, edsize );
      if( stored_crc != computed_crc )
        {
-        if( verbosity >= 2 )
+        if( verbosity < 1 ) return false;
-          std::fprintf( stderr, "CRC32-C = %08X\n", (unsigned)computed_crc );
+        const char * str = "CRC mismatch in extended records; stored %08X, computed %08X";
        if( !msg_vecp ) print_error( 0, str, stored_crc, computed_crc );
        else
          { msg_vecp->push_back( std::string() );
            format_error( msg_vecp->back(), 0, str, stored_crc, computed_crc ); }
        return false;
        }
      }
    else if( ( rest < 8 || std::memcmp( tail, "comment=", 8 ) != 0 ) &&
-             verbosity >= 1 ) unknown_keyword( tail, rest );
+             verbosity >= 1 ) unknown_keyword( tail, rest, msg_vecp );
    pos += rsize;
    }
  return true;
--- a/lzip_index.cc
+++ b/lzip_index.cc
@ -1,5 +1,5 @@
 /* Tarlz - Archiver with multimember lzip compression
-   Copyright (C) 2013-2024 Antonio Diaz Diaz.
+   Copyright (C) 2013-2025 Antonio Diaz Diaz.
   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
--- a/lzip_index.h
+++ b/lzip_index.h
@ -1,5 +1,5 @@
 /* Tarlz - Archiver with multimember lzip compression
-   Copyright (C) 2013-2024 Antonio Diaz Diaz.
+   Copyright (C) 2013-2025 Antonio Diaz Diaz.
   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
--- a/main.cc
+++ b/main.cc
@ -1,5 +1,5 @@
 /* Tarlz - Archiver with multimember lzip compression
-   Copyright (C) 2013-2024 Antonio Diaz Diaz.
+   Copyright (C) 2013-2025 Antonio Diaz Diaz.
   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
@ -57,7 +57,7 @@ const char * const program_name = "tarlz";
 namespace {
-const char * const program_year = "2024";
+const char * const program_year = "2025";
 const char * invocation_name = program_name;		// default value
@ -74,7 +74,7 @@ void show_help( const long num_online )
               "compressed archives.\n"
               "\nKeeping the alignment between tar members and lzip members has two\n"
               "advantages. It adds an indexed lzip layer on top of the tar archive, making\n"
-               "it possible to decode the archive safely in parallel. It also minimizes the\n"
+               "it possible to decode the archive safely in parallel. It also reduces the\n"
               "amount of data lost in case of corruption.\n"
               "\nThe tarlz file format is a safe POSIX-style backup format. In case of\n"
               "corruption, tarlz can extract all the undamaged members from the tar.lz\n"
@ -457,17 +457,43 @@ bool format_error( Resizable_buffer & rbuf, const int errcode,
  for( int i = 0; i < 2; ++i )		// resize rbuf if not large enough
    {
    int len = snprintf( rbuf(), rbuf.size(), "%s: ", program_name );
-    if( len >= (int)rbuf.size() && !rbuf.resize( len + 1 ) ) break;
+    if( !rbuf.resize( len + 1 ) ) break;
    va_start( args, format );
    len += vsnprintf( rbuf() + len, rbuf.size() - len, format, args );
    va_end( args );
-    if( len >= (int)rbuf.size() && !rbuf.resize( len + 1 ) ) break;
+    if( !rbuf.resize( len + 2 ) ) break;
-    if( errcode <= 0 ) rbuf()[len++] = '\n';
+    if( errcode <= 0 ) { rbuf()[len++] = '\n'; rbuf()[len] = 0; }
    else len += snprintf( rbuf() + len, rbuf.size() - len, ": %s\n",
                          std::strerror( errcode ) );
-    if( len < (int)rbuf.size() || !rbuf.resize( len + 1 ) ) break;
+    if( len < (int)rbuf.size() ) return true;
    if( i > 0 || !rbuf.resize( len + 1 ) ) break;
    }
-  return true;
+  return false;
  }
 bool format_error( std::string & msg, const int errcode,
                   const char * const format, ... )
  {
  if( verbosity < 0 ) return false;
  Resizable_buffer rbuf;
  if( !rbuf.size() ) return false;
  va_list args;
  for( int i = 0; i < 2; ++i )		// resize rbuf if not large enough
    {
    int len = snprintf( rbuf(), rbuf.size(), "%s: ", program_name );
    if( !rbuf.resize( len + 1 ) ) break;
    va_start( args, format );
    len += vsnprintf( rbuf() + len, rbuf.size() - len, format, args );
    va_end( args );
    if( !rbuf.resize( len + 2 ) ) break;
    if( errcode <= 0 ) { rbuf()[len++] = '\n'; rbuf()[len] = 0; }
    else len += snprintf( rbuf() + len, rbuf.size() - len, ": %s\n",
                          std::strerror( errcode ) );
    if( len < (int)rbuf.size() ) { msg.assign( rbuf(), len ); return true; }
    if( i > 0 || !rbuf.resize( len + 1 ) ) break;
    }
  return false;
  }
--- a/tarlz.h
+++ b/tarlz.h
@ -1,5 +1,5 @@
 /* Tarlz - Archiver with multimember lzip compression
-   Copyright (C) 2013-2024 Antonio Diaz Diaz.
+   Copyright (C) 2013-2025 Antonio Diaz Diaz.
   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
@ -120,7 +120,7 @@ public:
      }
    return true;
    }
-  char * operator()() { return p; }
+  char * operator()() { return p; }		// no need for operator[]
  const char * operator()() const { return p; }
  uint8_t * u8() { return (uint8_t *)p; }
  const uint8_t * u8() const { return (const uint8_t *)p; }
@ -184,7 +184,8 @@ class Extended			// stores metadata from/for extended records
  mutable bool crc_present_;
  void calculate_sizes() const;
-  void unknown_keyword( const char * const buf, const int size ) const;
+  void unknown_keyword( const char * const buf, const int size,
                        std::vector< std::string > * const msg_vecp = 0 ) const;
 public:
  static const std::string crc_record;
@ -234,7 +235,8 @@ public:
  bool crc_present() const { return crc_present_; }
  bool parse( const char * const buf, const int edsize,
-              const bool permissive );
+              const bool permissive,
              std::vector< std::string > * const msg_vecp = 0 );
  void fill_from_ustar( const Tar_header header );
  };
@ -279,7 +281,7 @@ public:
    return crc ^ 0xFFFFFFFFU;
    }
-  // Calculates the crc of size bytes except a window of 8 bytes at pos
+  // compute the crc of size bytes except a window of 8 bytes at pos
  uint32_t windowed_crc( const uint8_t * const buffer, const int pos,
                         const int size ) const
    {
@ -485,8 +487,9 @@ const char * const posix_lz_msg = "This does not look like a POSIX tar.lz archiv
 const char * const eclosa_msg = "Error closing archive";
 const char * const eclosf_msg = "Error closing file";
 const char * const nfound_msg = "Not found in archive.";
-const char * const seek_msg = "Seek error";
+const char * const rd_err_msg = "Read error";
 const char * const wr_err_msg = "Write error";
 const char * const seek_msg = "Seek error";
 const char * const chdir_msg = "Error changing working directory";
 const char * const intdir_msg = "Failed to create intermediate directory";
@ -503,7 +506,8 @@ bool show_member_name( const Extended & extended, const Tar_header header,
                       const int vlevel, Resizable_buffer & rbuf );
 bool check_skip_filename( const Cl_options & cl_opts,
                          std::vector< char > & name_pending,
-                          const char * const filename, const int chdir_fd = -1 );
+                          const char * const filename, const int cwd_fd = -1,
                          std::string * const msgp = 0 );
 bool make_dirs( const std::string & name );
 // defined in common_mutex.cc
@ -597,6 +601,8 @@ void show_error( const char * const msg, const int errcode = 0,
                 const bool help = false );
 bool format_error( Resizable_buffer & rbuf, const int errcode,
                   const char * const format, ... );
 bool format_error( std::string & msg, const int errcode,
                   const char * const format, ... );
 void print_error( const int errcode, const char * const format, ... );
 void format_file_error( std::string & estr, const char * const filename,
                        const char * const msg, const int errcode = 0 );
--- a/testsuite/check.sh
+++ b/testsuite/check.sh
--- a/testsuite/eoa_blocks.tar.lz
+++ b/testsuite/eoa_blocks.tar.lz
--- a/testsuite/eoa_blocks.tar
+++ b/testsuite/eoa_blocks.tar
--- a/testsuite/t155.tar
+++ b/testsuite/t155.tar
--- a/testsuite/t155_fv1.tar
+++ b/testsuite/t155_fv1.tar
--- a/testsuite/t155_fv2.tar
+++ b/testsuite/t155_fv2.tar
--- a/testsuite/t155_fv3.tar
+++ b/testsuite/t155_fv3.tar
--- a/testsuite/t155_fv7.tar.lz
+++ b/testsuite/t155_fv7.tar.lz
--- a/testsuite/test.txt.lz
+++ b/testsuite/test.txt.lz
--- a/testsuite/test.txt.tar
+++ b/testsuite/test.txt.tar
--- a/testsuite/test.txt.tar.lz
+++ b/testsuite/test.txt.tar.lz
--- a/testsuite/test3.tar
+++ b/testsuite/test3.tar
--- a/testsuite/test3.tar.lz
+++ b/testsuite/test3.tar.lz
--- a/testsuite/test3_bad1.tar.lz
+++ b/testsuite/test3_bad1.tar.lz
--- a/testsuite/test3_bad2.tar.lz
+++ b/testsuite/test3_bad2.tar.lz
--- a/testsuite/test3_bad3.tar.lz
+++ b/testsuite/test3_bad3.tar.lz
--- a/testsuite/test3_bad4.tar.lz
+++ b/testsuite/test3_bad4.tar.lz
--- a/testsuite/test3_bad5.tar.lz
+++ b/testsuite/test3_bad5.tar.lz
--- a/testsuite/test3_bad6.tar.lz
+++ b/testsuite/test3_bad6.tar.lz
--- a/testsuite/test3_crc.tar.lz
+++ b/testsuite/test3_crc.tar.lz
--- a/testsuite/test3_dir.tar
+++ b/testsuite/test3_dir.tar
--- a/testsuite/test3_eoa1.tar
+++ b/testsuite/test3_eoa1.tar
--- a/testsuite/test3_eoa1.tar.lz
+++ b/testsuite/test3_eoa1.tar.lz
--- a/testsuite/test3_eoa2.tar
+++ b/testsuite/test3_eoa2.tar
--- a/testsuite/test3_eoa2.tar.lz
+++ b/testsuite/test3_eoa2.tar.lz
--- a/testsuite/test3_eoa3.tar
+++ b/testsuite/test3_eoa3.tar
--- a/testsuite/test3_eoa3.tar.lz
+++ b/testsuite/test3_eoa3.tar.lz
--- a/testsuite/test3_eoa4.tar
+++ b/testsuite/test3_eoa4.tar
--- a/testsuite/test3_eoa4.tar.lz
+++ b/testsuite/test3_eoa4.tar.lz
--- a/testsuite/test3_eoa5.tar.lz
+++ b/testsuite/test3_eoa5.tar.lz
--- a/testsuite/test3_gh1.tar
+++ b/testsuite/test3_gh1.tar
--- a/testsuite/test3_gh1.tar.lz
+++ b/testsuite/test3_gh1.tar.lz
--- a/testsuite/test3_gh2.tar
+++ b/testsuite/test3_gh2.tar
--- a/testsuite/test3_gh2.tar.lz
+++ b/testsuite/test3_gh2.tar.lz
--- a/testsuite/test3_gh3.tar
+++ b/testsuite/test3_gh3.tar
--- a/testsuite/test3_gh3.tar.lz
+++ b/testsuite/test3_gh3.tar.lz
--- a/testsuite/test3_gh4.tar
+++ b/testsuite/test3_gh4.tar
--- a/testsuite/test3_gh4.tar.lz
+++ b/testsuite/test3_gh4.tar.lz
--- a/testsuite/test3_gh5.tar.lz
+++ b/testsuite/test3_gh5.tar.lz
--- a/testsuite/test3_gh6.tar.lz
+++ b/testsuite/test3_gh6.tar.lz
--- a/testsuite/test3_gh7.tar.lz
+++ b/testsuite/test3_gh7.tar.lz
--- a/testsuite/test3_gh8.tar.lz
+++ b/testsuite/test3_gh8.tar.lz
--- a/testsuite/test3_nn.tar
+++ b/testsuite/test3_nn.tar
--- a/testsuite/test3_nn.tar.lz
+++ b/testsuite/test3_nn.tar.lz
--- a/testsuite/test3_sm1.tar.lz
+++ b/testsuite/test3_sm1.tar.lz
--- a/testsuite/test3_sm2.tar.lz
+++ b/testsuite/test3_sm2.tar.lz
--- a/testsuite/test3_sm3.tar.lz
+++ b/testsuite/test3_sm3.tar.lz
--- a/testsuite/test3_sm4.tar.lz
+++ b/testsuite/test3_sm4.tar.lz
--- a/testsuite/test3_uk.tar.lz
+++ b/testsuite/test3_uk.tar.lz
--- a/testsuite/tlz_in_tar1.tar
+++ b/testsuite/tlz_in_tar1.tar
--- a/testsuite/tlz_in_tar2.tar
+++ b/testsuite/tlz_in_tar2.tar