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zutils/zutils.cc
Daniel Baumann 6b4ef5ad72
Adding upstream version 1.12. 
Signed-off-by: Daniel Baumann <daniel@debian.org>
2025-02-24 06:02:37 +01:00

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9.1 KiB
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/* Zutils - Utilities dealing with compressed files
Copyright (C) 2009-2023 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 <cerrno>
#include <csignal>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <string>
#include <vector>
#include <stdint.h>
#include <unistd.h>
#include <sys/wait.h>
#include "rc.h"
#include "zutils.h"
namespace {
inline bool isvalid_ds( const uint8_t ds ) // lzip valid dictionary_size
{
enum { min_dictionary_size = 1 << 12,
max_dictionary_size = 1 << 29 };
unsigned dictionary_size = ( 1 << ( ds & 0x1F ) );
if( dictionary_size > min_dictionary_size )
dictionary_size -= ( dictionary_size / 16 ) * ( ( ds >> 5 ) & 7 );
return ( dictionary_size >= min_dictionary_size &&
dictionary_size <= max_dictionary_size );
}
/* Return -1 if child not terminated, 2 in case of error, or exit status of
child process 'pid'. Return 0 if child was terminated by SIGPIPE.
*/
int child_status( const pid_t pid, const char * const name )
{
int status;
while( true )
{
const int tmp = waitpid( pid, &status, WNOHANG );
if( tmp == -1 && errno != EINTR )
{
if( verbosity >= 0 )
std::fprintf( stderr, "%s: Error checking status of '%s': %s\n",
program_name, name, std::strerror( errno ) );
_exit( 2 );
}
if( tmp == 0 ) return -1; // child not terminated
if( tmp == pid ) break; // child terminated
}
if( WIFEXITED( status ) ) return WEXITSTATUS( status );
if( WIFSIGNALED( status ) && WTERMSIG( status ) == SIGPIPE ) return 0;
return 2;
}
} // end namespace
/* Return the number of bytes really read.
If (value returned < size) and (errno == 0), means EOF was reached.
*/
int readblock( const int fd, uint8_t * const buf, const int size )
{
int sz = 0;
errno = 0;
while( sz < size )
{
const int n = read( fd, buf + sz, size - sz );
if( n > 0 ) sz += n;
else if( n == 0 ) break; // EOF
else if( errno != EINTR ) break;
errno = 0;
}
return sz;
}
/* Return the number of bytes really written.
If (value returned < size), it is always an error.
*/
int writeblock( const int fd, const uint8_t * const buf, const int size )
{
int sz = 0;
errno = 0;
while( sz < size )
{
const int n = write( fd, buf + sz, size - sz );
if( n > 0 ) sz += n;
else if( n < 0 && errno != EINTR ) break;
errno = 0;
}
return sz;
}
// filename == "-" means stdin.
//
bool feed_data( const std::string & filename, const int infd, const int outfd,
const uint8_t * magic_data, const int magic_size )
{
if( magic_size && writeblock( outfd, magic_data, magic_size ) != magic_size )
{ show_error( "Write error", errno ); return false; }
enum { buffer_size = 4096 };
uint8_t buffer[buffer_size];
while( true )
{
const int size = readblock( infd, buffer, buffer_size );
if( size != buffer_size && errno )
{ show_file_error( name_or_stdin( filename.c_str() ), "Read error",
errno ); return false; }
if( size > 0 && writeblock( outfd, buffer, size ) != size )
{ show_error( "Write error", errno ); return false; }
if( size < buffer_size ) break;
}
return true;
}
bool good_status( const Children & children, const bool finished )
{
bool error = false;
for( int i = 0; i < 2; ++i )
{
const pid_t pid = children.pid[i];
if( pid )
{
const char * const name =
( i == 0 ) ? "data feeder" : children.compressor_name;
// even if compressor finished, trailing data may remain in data feeder
if( i == 0 || !finished )
{
const int tmp = child_status( pid, name ); // 0 if SIGPIPE
if( tmp < 0 ) // child not terminated
{ kill( pid, SIGTERM ); wait_for_child( pid, name ); }
else if( tmp != 0 ) error = true; // child status != 0
}
else
if( wait_for_child( pid, name ) != 0 ) error = true;
}
}
return !error;
}
bool set_data_feeder( const std::string & filename, int * const infdp,
Children & children, int format_index )
{
uint8_t magic_data[magic_buf_size];
int magic_size = 0;
if( format_index < 0 )
format_index = test_format( *infdp, magic_data, &magic_size );
children.compressor_name = get_compressor_name( format_index );
if( children.compressor_name ) // compressed
{
int fda[2]; // pipe from feeder
int fda2[2]; // pipe from compressor
if( pipe( fda ) < 0 || pipe( fda2 ) < 0 )
{ show_error( "Can't create pipe", errno ); return false; }
const int old_infd = *infdp;
*infdp = fda2[0];
const pid_t pid = fork();
if( pid == 0 ) // child 1 (compressor feeder)
{
if( close( fda[0] ) != 0 ||
close( fda2[0] ) != 0 || close( fda2[1] ) != 0 ||
!feed_data( filename, old_infd, fda[1], magic_data, magic_size ) )
_exit( 2 );
if( close( fda[1] ) != 0 ) { show_close_error(); _exit( 2 ); }
_exit( 0 );
}
if( pid < 0 ) // parent
{ show_fork_error( "data feeder" ); return false; }
const pid_t pid2 = fork();
if( pid2 == 0 ) // child 2 (compressor)
{
if( dup2( fda[0], STDIN_FILENO ) >= 0 &&
dup2( fda2[1], STDOUT_FILENO ) >= 0 &&
close( fda[0] ) == 0 && close( fda[1] ) == 0 &&
close( fda2[0] ) == 0 && close( fda2[1] ) == 0 )
{
const std::vector< std::string > & compressor_args =
get_compressor_args( format_index );
const int size = compressor_args.size();
const char ** const argv = new const char *[size+3];
argv[0] = children.compressor_name;
for( int i = 0; i < size; ++i )
argv[i+1] = compressor_args[i].c_str();
argv[size+1] = ( verbosity >= 0 ) ? "-d" : "-dq";
argv[size+2] = 0;
execvp( argv[0], (char **)argv );
}
show_exec_error( children.compressor_name );
_exit( 2 );
}
if( pid2 < 0 ) // parent
{ show_fork_error( children.compressor_name ); return false; }
close( fda[0] ); close( fda[1] ); close( fda2[1] );
children.pid[0] = pid;
children.pid[1] = pid2;
}
else // uncompressed
{
int fda[2]; // pipe from feeder
if( pipe( fda ) < 0 )
{ show_error( "Can't create pipe", errno ); return false; }
const int old_infd = *infdp;
*infdp = fda[0];
const pid_t pid = fork();
if( pid == 0 ) // child (feeder)
{
if( close( fda[0] ) != 0 ||
!feed_data( filename, old_infd, fda[1], magic_data, magic_size ) )
_exit( 2 );
if( close( fda[1] ) != 0 ) { show_close_error(); _exit( 2 ); }
_exit( 0 );
}
if( pid < 0 ) // parent
{ show_fork_error( "data feeder" ); return false; }
close( fda[1] );
children.pid[0] = pid;
children.pid[1] = 0;
}
return true;
}
// Return format_index, or -1 if uncompressed.
//
int test_format( const int infd, uint8_t magic_data[],
int * const magic_sizep )
{
enum { bzip2_magic_size = 3,
gzip_magic_size = 2,
lzip_magic_size = 5,
xz_magic_size = 5,
zstd_magic_size = 4,
compress_magic_size = 2 };
const uint8_t bzip2_magic[bzip2_magic_size] =
{ 0x42, 0x5A, 0x68 }; // "BZh"
const uint8_t gzip_magic[gzip_magic_size] =
{ 0x1F, 0x8B };
const uint8_t compress_magic[compress_magic_size] =
{ 0x1F, 0x9D };
const uint8_t lzip_magic[lzip_magic_size] =
{ 0x4C, 0x5A, 0x49, 0x50, 0x01 }; // "LZIP\001"
const uint8_t xz_magic[xz_magic_size] =
{ 0xFD, 0x37, 0x7A, 0x58, 0x5A }; // 0xFD, "7zXZ"
const uint8_t zstd_magic[zstd_magic_size] =
{ 0x28, 0xB5, 0x2F, 0xFD }; // 0xFD2FB528 LE
*magic_sizep = readblock( infd, magic_data, magic_buf_size );
if( *magic_sizep == magic_buf_size ) // test formats in search order
{
if( std::memcmp( magic_data, lzip_magic, lzip_magic_size ) == 0 &&
isvalid_ds( magic_data[lzip_magic_size] ) )
return fmt_lz;
if( std::memcmp( magic_data, bzip2_magic, bzip2_magic_size ) == 0 &&
magic_data[3] >= '1' && magic_data[3] <= '9' &&
std::memcmp( magic_data + 4, "1AY&SY", 6 ) == 0 )
return fmt_bz2;
if( std::memcmp( magic_data, gzip_magic, gzip_magic_size ) == 0 ||
std::memcmp( magic_data, compress_magic, compress_magic_size ) == 0 )
return fmt_gz;
if( std::memcmp( magic_data, zstd_magic, zstd_magic_size ) == 0 )
return fmt_zst;
if( std::memcmp( magic_data, xz_magic, xz_magic_size ) == 0 )
return fmt_xz;
}
return -1;
}
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