Adding upstream version 0.25.upstream/0.25upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 765 insertions, 0 deletions

diff --git a/decode_lz.cc b/decode_lz.cc
new file mode 100644
index 0000000..867ffa5
--- /dev/null
+++ b/decode_lz.cc
@@ -0,0 +1,765 @@
+/* Tarlz - Archiver with multimember lzip compression
+   Copyright (C) 2013-2024 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
+   the Free Software Foundation, either version 2 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#define _FILE_OFFSET_BITS 64
+
+#include <algorithm>
+#include <cerrno>
+#include <cstdio>
+#include <queue>
+#include <pthread.h>
+#include <stdint.h>	// for lzlib.h
+#include <unistd.h>
+#include <utime.h>
+#include <sys/stat.h>
+#if !defined __FreeBSD__ && !defined __OpenBSD__ && !defined __NetBSD__ && \
+    !defined __DragonFly__ && !defined __APPLE__ && !defined __OS2__
+#include <sys/sysmacros.h>		// for major, minor, makedev
+#else
+#include <sys/types.h>			// for major, minor, makedev
+#endif
+#include <lzlib.h>
+
+#include "tarlz.h"
+#include "arg_parser.h"
+#include "lzip_index.h"
+#include "archive_reader.h"
+#include "common_mutex.h"
+#include "decode.h"
+
+/* 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.
+   - the muxer drains the queue and returns. */
+
+namespace {
+
+const char * const other_msg = "Other worker found an error.";
+
+/* line is preformatted and newline terminated except for prefix, error.
+   ok with an empty line is a no-op. */
+struct Packet			// member name and metadata or error message
+  {
+  enum Status { ok, member_done, diag, prefix, error1, error2 };
+
+  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
+  Packet( const long i, const char * const msg, const Status s, const int e )
+    : member_id( i ), line( msg ), status( s ), errcode( e ) {}
+  };
+
+
+class Packet_courier			// moves packets around
+  {
+public:
+  unsigned ocheck_counter;
+  unsigned owait_counter;
+private:
+  long error_member_id;		// first lzip member with error/misalign/eoa/eof
+  int deliver_worker_id;	// worker queue currently delivering packets
+  int master_worker_id;		// worker in charge if error/misalign/eoa/eof
+  std::vector< std::queue< const Packet * > > opacket_queues;
+  int num_working;			// number of workers still running
+  const int num_workers;		// number of workers
+  const unsigned out_slots;		// max output packets per queue
+  pthread_mutex_t omutex;
+  pthread_cond_t oav_or_exit;	// output packet available or all workers exited
+  std::vector< pthread_cond_t > slot_av;	// output slot available
+  pthread_cond_t check_master;
+  bool eoa_found_;				// EOA blocks found
+
+  Packet_courier( const Packet_courier & );	// declared as private
+  void operator=( const Packet_courier & );	// declared as private
+
+public:
+  Packet_courier( const int workers, const int slots )
+    : ocheck_counter( 0 ), owait_counter( 0 ),
+      error_member_id( -1 ), deliver_worker_id( 0 ), master_worker_id( -1 ),
+      opacket_queues( workers ), num_working( workers ),
+      num_workers( workers ), out_slots( slots ), slot_av( workers ),
+      eoa_found_( false )
+    {
+    xinit_mutex( &omutex ); xinit_cond( &oav_or_exit );
+    for( unsigned i = 0; i < slot_av.size(); ++i ) xinit_cond( &slot_av[i] );
+    xinit_cond( &check_master );
+    }
+
+  ~Packet_courier()
+    {
+    xdestroy_cond( &check_master );
+    for( unsigned i = 0; i < slot_av.size(); ++i ) xdestroy_cond( &slot_av[i] );
+    xdestroy_cond( &oav_or_exit ); xdestroy_mutex( &omutex );
+    }
+
+  bool eoa_found() const { return eoa_found_; }
+  void report_eoa() { eoa_found_ = true; }
+
+  bool mastership_granted() const { return master_worker_id >= 0; }
+
+  bool request_mastership( const long member_id, const int worker_id )
+    {
+    xlock( &omutex );
+    if( mastership_granted() )			// already granted
+      { xunlock( &omutex ); return ( master_worker_id == worker_id ); }
+    if( error_member_id < 0 || error_member_id > member_id )
+      error_member_id = member_id;
+    while( !mastership_granted() && ( worker_id != deliver_worker_id ||
+           !opacket_queues[deliver_worker_id].empty() ) )
+      xwait( &check_master, &omutex );
+    if( !mastership_granted() && worker_id == deliver_worker_id &&
+        opacket_queues[deliver_worker_id].empty() )
+      {
+      master_worker_id = worker_id;		// grant mastership
+      for( int i = 0; i < num_workers; ++i )	// delete all packets
+        while( !opacket_queues[i].empty() )
+          opacket_queues[i].pop();
+      xbroadcast( &check_master );
+      xunlock( &omutex );
+      return true;
+      }
+    xunlock( &omutex );
+    return false;		// mastership granted to another worker
+    }
+
+  void worker_finished()
+    {
+    // notify muxer when last worker exits
+    xlock( &omutex );
+    if( --num_working == 0 ) xsignal( &oav_or_exit );
+    xunlock( &omutex );
+    }
+
+  /* Collect a packet from a worker.
+     If a packet is rejected, the worker must terminate. */
+  bool collect_packet( const long member_id, const int worker_id,
+                       const char * const msg, const Packet::Status status,
+                       const int errcode = 0 )
+    {
+    const Packet * const opacket = new Packet( member_id, msg, status, errcode );
+    xlock( &omutex );
+    if( ( mastership_granted() && master_worker_id != worker_id ) ||
+        ( error_member_id >= 0 && error_member_id < opacket->member_id ) )
+      { xunlock( &omutex ); delete opacket; return false; }	// reject packet
+    while( opacket_queues[worker_id].size() >= out_slots )
+      xwait( &slot_av[worker_id], &omutex );
+    opacket_queues[worker_id].push( opacket );
+    if( worker_id == deliver_worker_id ) xsignal( &oav_or_exit );
+    xunlock( &omutex );
+    return true;
+    }
+
+  /* Deliver a packet to muxer.
+     If packet.status == Packet::member_done, move to next queue.
+     If packet.line.empty(), wait again (empty lzip member). */
+  const Packet * deliver_packet()
+    {
+    const Packet * opacket = 0;
+    xlock( &omutex );
+    ++ocheck_counter;
+    while( true )
+      {
+      while( opacket_queues[deliver_worker_id].empty() && num_working > 0 )
+        {
+        ++owait_counter;
+        if( !mastership_granted() && error_member_id >= 0 )
+          xbroadcast( &check_master );	// mastership requested not yet granted
+        xwait( &oav_or_exit, &omutex );
+        }
+      if( opacket_queues[deliver_worker_id].empty() ) break;
+      opacket = opacket_queues[deliver_worker_id].front();
+      opacket_queues[deliver_worker_id].pop();
+      if( opacket_queues[deliver_worker_id].size() + 1 == out_slots )
+        xsignal( &slot_av[deliver_worker_id] );
+      if( opacket->status == Packet::member_done && !mastership_granted() )
+        { if( ++deliver_worker_id >= num_workers ) deliver_worker_id = 0; }
+      if( !opacket->line.empty() ) break;
+      delete opacket; opacket = 0;
+      }
+    xunlock( &omutex );
+    return opacket;
+    }
+
+  bool finished()		// all packets delivered to muxer
+    {
+    if( num_working != 0 ) return false;
+    for( int i = 0; i < num_workers; ++i )
+      if( !opacket_queues[i].empty() ) return false;
+    return true;
+    }
+  };
+
+
+// prevent two threads from extracting the same file at the same time
+class Name_monitor
+  {
+  std::vector< unsigned > crc_vector;
+  std::vector< std::string > name_vector;
+  pthread_mutex_t mutex;
+
+public:
+  Name_monitor( const int num_workers )
+    : crc_vector( num_workers ), name_vector( num_workers )
+    { if( num_workers > 0 ) xinit_mutex( &mutex ); }
+
+  bool reserve_name( const unsigned worker_id, const std::string & filename )
+    {
+    // compare the CRCs of the names; compare the names if the CRCs collide
+    const unsigned crc =
+      crc32c.compute_crc( (const uint8_t *)filename.c_str(), filename.size() );
+    xlock( &mutex );
+    for( unsigned i = 0; i < crc_vector.size(); ++i )
+      if( crc_vector[i] == crc && crc != 0 && i != worker_id &&
+          name_vector[i] == filename )
+        { xunlock( &mutex ); return false; }	// filename already reserved
+    crc_vector[worker_id] = crc; name_vector[worker_id] = filename;
+    xunlock( &mutex );
+    return true;
+    }
+  };
+
+
+struct Trival				// triple result value
+  {
+  const char * msg;
+  int errcode;
+  int retval;
+  explicit Trival( const char * const s = 0, const int e = 0, const int r = 0 )
+    : msg( s ), errcode( e ), retval( r ) {}
+  };
+
+
+Trival skip_member_lz( Archive_reader_i & ar, Packet_courier & courier,
+                       const Extended & extended, const long member_id,
+                       const int worker_id, const Typeflag typeflag )
+  {
+  if( data_may_follow( typeflag ) )
+    { const int ret = ar.skip_member( extended );
+      if( ret != 0 ) return Trival( ar.e_msg(), ar.e_code(), ret ); }
+  if( ar.at_member_end() &&
+      !courier.collect_packet( member_id, worker_id, "", Packet::member_done ) )
+    return Trival( other_msg, 0, 1);
+  return Trival();
+  }
+
+
+Trival compare_member_lz( const Cl_options & cl_opts,
+                          Archive_reader_i & ar, Packet_courier & courier,
+                          const Extended & extended, const Tar_header header,
+                          Resizable_buffer & rbuf, const long member_id,
+                          const int worker_id )
+  {
+  if( verbosity < 1 ) rbuf()[0] = 0;
+  else if( !format_member_name( extended, header, rbuf, verbosity > 1 ) )
+    return Trival( mem_msg, 0, 1 );
+  std::string estr, ostr;
+  const bool stat_differs =
+    !compare_file_type( estr, ostr, cl_opts, extended, header );
+  if( ( rbuf()[0] && !courier.collect_packet( member_id, worker_id, rbuf(),
+                                              Packet::ok ) ) ||
+      ( estr.size() && !courier.collect_packet( member_id, worker_id,
+                                              estr.c_str(), Packet::diag ) ) ||
+      ( ostr.size() && !courier.collect_packet( member_id, worker_id,
+                                              ostr.c_str(), Packet::ok ) ) ||
+      ( extended.file_size() <= 0 && ar.at_member_end() &&
+        !courier.collect_packet( member_id, worker_id, "", Packet::member_done ) ) )
+    return Trival( other_msg, 0, 1 );
+  if( extended.file_size() <= 0 ) return Trival();
+  const Typeflag typeflag = (Typeflag)header[typeflag_o];
+  if( ( typeflag != tf_regular && typeflag != tf_hiperf ) || stat_differs )
+    return skip_member_lz( ar, courier, extended, member_id, worker_id, typeflag );
+  // else compare file contents
+  const char * const filename = extended.path().c_str();
+  const int infd2 = open_instream( filename );
+  if( infd2 < 0 ) { set_error_status( 1 );
+    return skip_member_lz( ar, courier, extended, member_id, worker_id, typeflag ); }
+  const int ret = compare_file_contents( estr, ostr, ar, extended.file_size(),
+                                         filename, infd2 );
+  if( ret != 0 ) return Trival( ar.e_msg(), ar.e_code(), ret );
+  if( ( estr.size() && !courier.collect_packet( member_id, worker_id,
+                                              estr.c_str(), Packet::diag ) ) ||
+      ( ostr.size() && !courier.collect_packet( member_id, worker_id,
+                                              ostr.c_str(), Packet::ok ) ) ||
+      ( ar.at_member_end() &&
+        !courier.collect_packet( member_id, worker_id, "", Packet::member_done ) ) )
+    return Trival( other_msg, 0, 1 );
+  return Trival();
+  }
+
+
+Trival list_member_lz( Archive_reader_i & ar, Packet_courier & courier,
+                       const Extended & extended, const Tar_header header,
+                       Resizable_buffer & rbuf, const long member_id,
+                       const int worker_id )
+  {
+  if( verbosity < 0 ) rbuf()[0] = 0;
+  else if( !format_member_name( extended, header, rbuf, verbosity > 0 ) )
+    return Trival( mem_msg, 0, 1 );
+  const int ret = data_may_follow( (Typeflag)header[typeflag_o] ) ?
+    ar.skip_member( extended ) : 0;	// print name even on read error
+  if( !courier.collect_packet( member_id, worker_id, rbuf(),
+                   ar.at_member_end() ? Packet::member_done : Packet::ok ) )
+    return Trival( other_msg, 0, 1 );
+  if( ret != 0 ) return Trival( ar.e_msg(), ar.e_code(), ret );
+  return Trival();
+  }
+
+
+Trival extract_member_lz( const Cl_options & cl_opts,
+                          Archive_reader_i & ar, Packet_courier & courier,
+                          const Extended & extended, const Tar_header header,
+                          Resizable_buffer & rbuf, const long member_id,
+                          const int worker_id, Name_monitor & name_monitor )
+  {
+  const char * const filename = extended.path().c_str();
+  const Typeflag typeflag = (Typeflag)header[typeflag_o];
+  if( contains_dotdot( filename ) )
+    {
+    if( format_file_error( rbuf, filename, dotdot_msg ) &&
+        !courier.collect_packet( member_id, worker_id, rbuf(), Packet::diag ) )
+      return Trival( other_msg, 0, 1 );
+    return skip_member_lz( ar, courier, extended, member_id, worker_id, typeflag );
+    }
+  // skip member if another copy is already being extracted by another thread
+  if( !name_monitor.reserve_name( worker_id, extended.path() ) )
+    {
+    if( verbosity >= 3 && format_file_error( rbuf, filename,
+                       "Is being extracted by another thread, skipping." ) &&
+        !courier.collect_packet( member_id, worker_id, rbuf(), Packet::diag ) )
+      return Trival( other_msg, 0, 1 );
+    return skip_member_lz( ar, courier, extended, member_id, worker_id, typeflag );
+    }
+  mode_t mode = parse_octal( header + mode_o, mode_l );	 // 12 bits
+  if( geteuid() != 0 && !cl_opts.preserve_permissions ) mode &= ~get_umask();
+  int outfd = -1;
+
+  if( verbosity >= 1 )
+    {
+    if( !format_member_name( extended, header, rbuf, verbosity > 1 ) )
+      return Trival( mem_msg, 0, 1 );
+    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.
+     Don't remove an empty dir because other thread may need it. */
+  if( typeflag != tf_directory ) std::remove( filename );
+  if( !make_dirs( filename ) )
+    {
+    if( format_file_error( rbuf, filename, intdir_msg, errno ) &&
+        !courier.collect_packet( member_id, worker_id, rbuf(), Packet::diag ) )
+      return Trival( other_msg, 0, 1 );
+    set_error_status( 1 );
+    return skip_member_lz( ar, courier, extended, member_id, worker_id, typeflag );
+    }
+
+  switch( typeflag )
+    {
+    case tf_regular:
+    case tf_hiperf:
+      outfd = open_outstream( filename, true, &rbuf );
+      if( outfd < 0 )
+        {
+        if( verbosity >= 0 &&
+            !courier.collect_packet( member_id, worker_id, rbuf(), Packet::diag ) )
+          return Trival( other_msg, 0, 1 );
+        set_error_status( 1 );
+        return skip_member_lz( ar, courier, extended, member_id, worker_id,
+                               typeflag );
+        }
+      break;
+    case tf_link:
+    case tf_symlink:
+      {
+      const char * const linkname = extended.linkpath().c_str();
+      const bool hard = typeflag == tf_link;
+      if( ( hard && link( linkname, filename ) != 0 ) ||
+          ( !hard && symlink( linkname, filename ) != 0 ) )
+        {
+        if( format_error( rbuf, errno, cantln_msg, hard ? "" : "sym",
+                          linkname, filename ) &&
+            !courier.collect_packet( member_id, worker_id, rbuf(), Packet::diag ) )
+          return Trival( other_msg, 0, 1 );
+        set_error_status( 1 );
+        }
+      } 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 ) &&
+            !courier.collect_packet( member_id, worker_id, rbuf(), Packet::diag ) )
+          return Trival( other_msg, 0, 1 );
+        set_error_status( 1 );
+        }
+      } break;
+    case tf_chardev:
+    case tf_blockdev:
+      {
+      const unsigned dev =
+        makedev( parse_octal( header + devmajor_o, devmajor_l ),
+                 parse_octal( header + devminor_o, devminor_l ) );
+      const int dmode = ( typeflag == tf_chardev ? S_IFCHR : S_IFBLK ) | mode;
+      if( mknod( filename, dmode, dev ) != 0 )
+        {
+        if( format_file_error( rbuf, filename, mknod_msg, errno ) &&
+            !courier.collect_packet( member_id, worker_id, rbuf(), Packet::diag ) )
+          return Trival( other_msg, 0, 1 );
+        set_error_status( 1 );
+        }
+      break;
+      }
+    case tf_fifo:
+      if( mkfifo( filename, mode ) != 0 )
+        {
+        if( format_file_error( rbuf, filename, mkfifo_msg, errno ) &&
+            !courier.collect_packet( member_id, worker_id, rbuf(), Packet::diag ) )
+          return Trival( other_msg, 0, 1 );
+        set_error_status( 1 );
+        }
+      break;
+    default:
+      if( format_error( rbuf, 0, uftype_msg, filename, typeflag ) &&
+          !courier.collect_packet( member_id, worker_id, rbuf(), Packet::diag ) )
+        return Trival( other_msg, 0, 1 );
+      set_error_status( 2 );
+      return skip_member_lz( ar, courier, extended, member_id, worker_id,
+                             typeflag );
+    }
+
+  const bool islink = ( typeflag == tf_link || typeflag == tf_symlink );
+  errno = 0;
+  if( !islink &&
+      ( !uid_gid_in_range( extended.get_uid(), extended.get_gid() ) ||
+        chown( filename, extended.get_uid(), extended.get_gid() ) != 0 ) )
+    {
+    if( outfd >= 0 ) mode &= ~( S_ISUID | S_ISGID | S_ISVTX );
+    // chown in many cases returns with EPERM, which can be safely ignored.
+    if( errno != EPERM && errno != EINVAL )
+      {
+      if( format_file_error( rbuf, filename, chown_msg, errno ) &&
+          !courier.collect_packet( member_id, worker_id, rbuf(), Packet::diag ) )
+        return Trival( other_msg, 0, 1 );
+      set_error_status( 1 );
+      }
+    }
+
+  if( outfd >= 0 ) fchmod( outfd, mode );		// ignore errors
+
+  if( data_may_follow( typeflag ) )
+    {
+    const int bufsize = 32 * header_size;
+    uint8_t buf[bufsize];
+    long long rest = extended.file_size();
+    const int rem = rest % header_size;
+    const int padding = rem ? header_size - rem : 0;
+    while( rest > 0 )
+      {
+      const int rsize = ( rest >= bufsize ) ? bufsize : rest + padding;
+      const int ret = ar.read( buf, rsize );
+      if( ret != 0 )
+        {
+        if( outfd >= 0 )
+          {
+          if( cl_opts.keep_damaged )
+            { writeblock( outfd, buf, std::min( rest, (long long)ar.e_size() ) );
+              close( outfd ); }
+          else { close( outfd ); std::remove( filename ); }
+          }
+        return Trival( ar.e_msg(), ar.e_code(), ret );
+        }
+      const int wsize = ( rest >= bufsize ) ? bufsize : rest;
+      if( outfd >= 0 && writeblock( outfd, buf, wsize ) != wsize )
+        { format_file_error( rbuf, filename, werr_msg, errno );
+          return Trival( rbuf(), 0, 1 ); }
+      rest -= wsize;
+      }
+    }
+  if( outfd >= 0 && close( outfd ) != 0 )
+      { format_file_error( rbuf, filename, eclosf_msg, errno );
+        return Trival( rbuf(), 0, 1 ); }
+  if( !islink )
+    {
+    struct utimbuf t;
+    t.actime = extended.atime().sec();
+    t.modtime = extended.mtime().sec();
+    utime( filename, &t );			// ignore errors
+    }
+  if( ar.at_member_end() &&
+      !courier.collect_packet( member_id, worker_id, "", Packet::member_done ) )
+    return Trival( other_msg, 0, 1 );
+  return Trival();
+  }
+
+
+struct Worker_arg
+  {
+  const Cl_options * cl_opts;
+  const Archive_descriptor * ad;
+  Packet_courier * courier;
+  Name_monitor * name_monitor;
+  std::vector< char > * name_pending;
+  int worker_id;
+  int num_workers;
+  };
+
+
+/* Read lzip members from archive, decode their tar members, and give the
+   packets produced to courier.
+*/
+extern "C" void * dworker( void * arg )
+  {
+  const Worker_arg & tmp = *(const Worker_arg *)arg;
+  const Cl_options & cl_opts = *tmp.cl_opts;
+  const Archive_descriptor & ad = *tmp.ad;
+  Packet_courier & courier = *tmp.courier;
+  Name_monitor & name_monitor = *tmp.name_monitor;
+  std::vector< char > & name_pending = *tmp.name_pending;
+  const int worker_id = tmp.worker_id;
+  const int num_workers = tmp.num_workers;
+
+  bool master = false;
+  Resizable_buffer rbuf;
+  Archive_reader_i ar( ad );			// 1 of N parallel readers
+  if( !rbuf.size() || ar.fatal() )
+    { if( courier.request_mastership( worker_id, worker_id ) )
+        courier.collect_packet( worker_id, worker_id, mem_msg, Packet::error1 );
+      goto done; }
+
+  for( long i = worker_id; !master && i < ad.lzip_index.members(); i += num_workers )
+    {
+    if( ad.lzip_index.dblock( i ).size() <= 0 )		// empty lzip member
+      {
+      if( courier.collect_packet( i, worker_id, "", Packet::member_done ) )
+        continue; else break;
+      }
+
+    long long data_end = ad.lzip_index.dblock( i ).end();
+    Extended extended;			// metadata from extended records
+    bool prev_extended = false;		// prev header was extended
+    ar.set_member( i );			// prepare for new member
+    while( true )			// process one tar header per iteration
+      {
+      if( ar.data_pos() >= data_end )	// dblock.end or udata_size
+        {
+        if( ar.data_pos() == data_end && !prev_extended ) break;
+        // member end exceeded or ends in extended, process rest of file
+        if( !courier.request_mastership( i, worker_id ) ) goto done;
+        master = true;
+        if( data_end >= ad.lzip_index.udata_size() )
+          { courier.collect_packet( i, worker_id, end_msg, Packet::error2 );
+            goto done; }
+        data_end = ad.lzip_index.udata_size();
+        if( ar.data_pos() == data_end && !prev_extended ) break;
+        }
+      Tar_header header;
+      const int ret = ar.read( header, header_size );
+      if( ret != 0 )
+        { if( courier.request_mastership( i, worker_id ) )
+            courier.collect_packet( i, worker_id, ar.e_msg(),
+                    ( ret == 1 ) ? Packet::error1 : Packet::error2, ar.e_code() );
+          goto done; }
+      if( !check_ustar_chksum( header ) )		// error or EOA
+        {
+        if( !courier.request_mastership( i, worker_id ) ) goto done;
+        if( block_is_zero( header, header_size ) )	// EOA
+          {
+          if( !prev_extended || cl_opts.permissive ) courier.report_eoa();
+          else courier.collect_packet( i, worker_id, fv_msg1, Packet::error2 );
+          goto done;
+          }
+        courier.collect_packet( i, worker_id, ( ar.data_pos() > header_size ) ?
+                                bad_hdr_msg : posix_lz_msg, Packet::error2 );
+        goto done;
+        }
+
+      const Typeflag typeflag = (Typeflag)header[typeflag_o];
+      if( typeflag == tf_global )
+        {
+        const char * msg = 0; int ret = 2;
+        Extended dummy;		// global headers are parsed and ignored
+        if( prev_extended && !cl_opts.permissive ) msg = fv_msg2;
+        else if( ( ret = ar.parse_records( dummy, header, rbuf, gblrec_msg,
+                 true ) ) != 0 ) msg = ar.e_msg();
+        else
+          {
+          if( ar.data_pos() == data_end &&	// end of lzip member or EOF
+              !courier.collect_packet( i, worker_id, "", Packet::member_done ) )
+            goto done;
+          continue;
+          }
+        if( courier.request_mastership( i, worker_id ) )
+          courier.collect_packet( i, worker_id, msg, ( ret == 1 ) ?
+                                  Packet::error1 : Packet::error2 );
+        goto done;
+        }
+      if( typeflag == tf_extended )
+        {
+        const char * msg = 0; int ret = 2;
+        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();
+        else if( !extended.crc_present() && cl_opts.missing_crc )
+          { msg = miscrc_msg; ret = 2; }
+        else { prev_extended = true; continue; }
+        if( courier.request_mastership( i, worker_id ) )
+          courier.collect_packet( i, worker_id, msg, ( ret == 1 ) ?
+                                  Packet::error1 : Packet::error2 );
+        goto done;
+        }
+      prev_extended = false;
+
+      extended.fill_from_ustar( header );	// copy metadata from header
+
+      /* 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. */
+      Trival trival;
+      if( check_skip_filename( cl_opts, name_pending, extended.path().c_str() ) )
+        trival = skip_member_lz( ar, courier, extended, i, worker_id, typeflag );
+      else
+        {
+        std::string rpmsg;
+        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; }
+        if( cl_opts.program_mode == m_list )
+          trival = list_member_lz( ar, courier, extended, header, rbuf, i, worker_id );
+        else if( extended.path().empty() )
+          trival = skip_member_lz( ar, courier, extended, i, worker_id, typeflag );
+        else if( cl_opts.program_mode == m_diff )
+          trival = compare_member_lz( cl_opts, ar, courier, extended, header,
+                                      rbuf, i, worker_id );
+        else trival = extract_member_lz( cl_opts, ar, courier, extended, header,
+                                         rbuf, i, worker_id, name_monitor );
+        }
+      if( trival.retval )				// fatal error
+fatal:  { if( courier.request_mastership( i, worker_id ) )
+            courier.collect_packet( i, worker_id, trival.msg,
+                    ( trival.retval == 1 ) ? Packet::error1 : Packet::error2,
+                    trival.errcode );
+          goto done; }
+      extended.reset();
+      }
+    }
+done:
+  courier.worker_finished();
+  return 0;
+  }
+
+
+/* Get from courier the processed and sorted packets, and print
+   the member lines on stdout or the diagnostics and errors on stderr.
+*/
+void muxer( const char * const archive_namep, Packet_courier & courier )
+  {
+  int retval = 0;
+  while( retval == 0 )
+    {
+    const Packet * const opacket = courier.deliver_packet();
+    if( !opacket ) break;	// queue is empty. all workers exited
+
+    switch( opacket->status )
+      {
+      case Packet::error1:
+      case Packet::error2:
+        show_file_error( archive_namep, opacket->line.c_str(), opacket->errcode );
+        retval = ( opacket->status == Packet::error1 ) ? 1 : 2; break;
+      case Packet::prefix: show_error( opacket->line.c_str() ); break;
+      case Packet::diag: std::fputs( opacket->line.c_str(), stderr ); break;
+      default: if( opacket->line.size() )
+        { std::fputs( opacket->line.c_str(), stdout ); std::fflush( stdout ); }
+      }
+    delete opacket;
+    }
+  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 );
+  }
+
+} // end namespace
+
+
+// init the courier, then start the workers and call the muxer.
+int decode_lz( const Cl_options & cl_opts, const Archive_descriptor & ad,
+               std::vector< char > & name_pending )
+  {
+  const int out_slots = 65536;		// max small files (<=512B) in 64 MiB
+  const int num_workers =		// limited to number of members
+    std::min( (long)cl_opts.num_workers, ad.lzip_index.members() );
+  if( cl_opts.program_mode == m_extract ) get_umask();	// cache the umask
+  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];
+  pthread_t * worker_threads = new( std::nothrow ) pthread_t[num_workers];
+  if( !worker_args || !worker_threads ) { show_error( mem_msg ); return 1; }
+  for( int i = 0; i < num_workers; ++i )
+    {
+    worker_args[i].cl_opts = &cl_opts;
+    worker_args[i].ad = &ad;
+    worker_args[i].courier = &courier;
+    worker_args[i].name_monitor = &name_monitor;
+    worker_args[i].name_pending = &name_pending;
+    worker_args[i].worker_id = i;
+    worker_args[i].num_workers = num_workers;
+    const int errcode =
+      pthread_create( &worker_threads[i], 0, dworker, &worker_args[i] );
+    if( errcode )
+      { show_error( "Can't create worker threads", errcode ); exit_fail_mt(); }
+    }
+
+  muxer( ad.namep, courier );
+
+  for( int i = num_workers - 1; i >= 0; --i )
+    {
+    const int errcode = pthread_join( worker_threads[i], 0 );
+    if( errcode )
+      { show_error( "Can't join worker threads", errcode ); exit_fail_mt(); }
+    }
+  delete[] worker_threads;
+  delete[] worker_args;
+
+  int retval = 0;
+  if( close( ad.infd ) != 0 )
+    { show_file_error( ad.namep, eclosa_msg, errno ); retval = 1; }
+
+  if( retval == 0 )
+    for( int i = 0; i < cl_opts.parser.arguments(); ++i )
+      if( nonempty_arg( cl_opts.parser, i ) && name_pending[i] )
+        { show_file_error( cl_opts.parser.argument( i ).c_str(), nfound_msg );
+          retval = 1; }
+
+  if( cl_opts.debug_level & 1 )
+    std::fprintf( stderr,
+      "muxer tried to consume from workers       %8u times\n"
+      "muxer had to wait                         %8u times\n",
+      courier.ocheck_counter,
+      courier.owait_counter );
+
+  if( !courier.finished() ) internal_error( conofin_msg );
+  return final_exit_status( retval, cl_opts.program_mode != m_diff );
+  }