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/* Zgrep - search compressed files for a regular expression
Copyright (C) 2010, 2011 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 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
void show_zgrep_help() throw()
{
std::printf( "Zgrep is a front end to the grep program that allows transparent search\n" );
std::printf( "on any combination of compressed and non-compressed files. If any given\n" );
std::printf( "file is compressed, its uncompressed content is used. If a given file\n" );
std::printf( "does not exist, and its name does not end with one of the known\n" );
std::printf( "extensions, zgrep tries the compressed file names corresponding to the\n" );
std::printf( "supported compressors. If no files are specified, data is read from\n" );
std::printf( "standard input, decompressed if needed, and fed to grep. Data read from\n" );
std::printf( "standard input must be of the same type; all uncompressed or all\n" );
std::printf( "compressed with the same compressor.\n" );
std::printf( "The supported compressors are bzip2, gzip, lzip and xz.\n" );
std::printf( "\nUsage: zgrep [options] <pattern> [files]\n" );
std::printf( "\nExit status is 0 if match, 1 if no match, 2 if trouble.\n" );
std::printf( "\nOptions:\n" );
std::printf( " --help display this help and exit\n" );
std::printf( " -V, --version output version information and exit\n" );
std::printf( " -a, --text treat all files as text\n" );
std::printf( " -A, --after-context=<n> print <n> lines of trailing context\n" );
std::printf( " -b, --byte-offset print the byte offset of each line\n" );
std::printf( " -B, --before-context=<n> print <n> lines of leading context\n" );
std::printf( " -c, --count only print a count of matching lines per file\n" );
std::printf( " -C, --context=<n> print <n> lines of output context\n" );
std::printf( " -e, --regexp=<pattern> use <pattern> as the pattern to match\n" );
std::printf( " -E, --extended-regexp <pattern> is an extended regular expression\n" );
std::printf( " -f, --file=<file> obtain patterns from <file>\n" );
std::printf( " -F, --fixed-strings <pattern> is a set of newline-separated strings\n" );
std::printf( " -h, --no-filename suppress the prefixing filename on output\n" );
std::printf( " -H, --with-filename print the filename for each match\n" );
std::printf( " -i, --ignore-case ignore case distinctions\n" );
std::printf( " -I ignore binary files\n" );
std::printf( " -l, --files-with-matches only print names of files containing matches\n" );
std::printf( " -L, --files-without-match only print names of files containing no matches\n" );
std::printf( " -m, --max-count=<n> stop after <n> matches\n" );
std::printf( " -n, --line-number print the line number of each line\n" );
std::printf( " -o, --only-matching show only the part of a line matching <pattern>\n" );
std::printf( " -q, --quiet suppress all messages\n" );
std::printf( " -r, --recursive operate recursively on directories\n" );
std::printf( " -s, --no-messages suppress error messages\n" );
std::printf( " -v, --invert-match select non-matching lines\n" );
std::printf( " --verbose verbose mode (show error messages)\n" );
std::printf( " -w, --word-regexp match only whole words\n" );
std::printf( " -x, --line-regexp match only whole lines\n" );
show_help_addr();
}
int zgrep_stdin( int infd, const std::vector< const char * > & grep_args )
{
pid_t pid;
if( !set_data_feeder( &infd, &pid ) ) return 2;
const pid_t grep_pid = fork();
if( grep_pid == 0 ) // child (grep)
{
if( dup2( infd, STDIN_FILENO ) >= 0 && close( infd ) == 0 )
{
const char ** const argv = new const char *[grep_args.size()+2];
argv[0] = GREP;
for( unsigned int i = 0; i < grep_args.size(); ++i )
argv[i+1] = grep_args[i];
argv[grep_args.size()+1] = 0;
execvp( argv[0], (char **)argv );
}
show_exec_error( GREP );
_exit( 2 );
}
// parent
if( grep_pid < 0 )
{ show_fork_error( GREP ); return 2; }
int retval = wait_for_child( grep_pid, GREP );
if( retval != 1 )
{ if( pid ) kill( pid, SIGTERM ); }
else
if( pid && wait_for_child( pid, "data feeder" ) != 0 ) retval = 2;
if( close( infd ) != 0 )
{ show_close_error( "data feeder" ); return 2; }
return retval;
}
int zgrep_file( int infd, const std::string & input_filename,
const std::vector< const char * > & grep_args,
const bool grep_list, const bool grep_show_name )
{
pid_t pid;
if( !set_data_feeder( &infd, &pid ) ) return 2;
int fda[2]; // pipe from grep
if( pipe( fda ) < 0 )
{ show_error( "Can't create pipe", errno ); return 2; }
const pid_t grep_pid = fork();
if( grep_pid == 0 ) // child (grep)
{
if( dup2( infd, STDIN_FILENO ) >= 0 &&
dup2( fda[1], STDOUT_FILENO ) >= 0 &&
close( infd ) == 0 && close( fda[0] ) == 0 && close( fda[1] ) == 0 )
{
const char ** const argv = new const char *[grep_args.size()+2];
argv[0] = GREP;
for( unsigned int i = 0; i < grep_args.size(); ++i )
argv[i+1] = grep_args[i];
argv[grep_args.size()+1] = 0;
execvp( argv[0], (char **)argv );
}
show_exec_error( GREP );
_exit( 2 );
}
// parent
close( fda[1] );
if( grep_pid < 0 )
{ show_fork_error( GREP ); return 2; }
enum { buffer_size = 256 };
uint8_t buffer[buffer_size];
bool line_begin = true;
while( true )
{
const int size = readblock( fda[0], buffer, buffer_size );
if( size != buffer_size && errno )
{ show_error( "Read error", errno ); return 2; }
if( size > 0 && !grep_list )
{
if( grep_show_name )
for( int i = 0; i < size; ++i )
{
if( line_begin )
{ line_begin = false; std::printf( "%s:", input_filename.c_str() ); }
if( buffer[i] == '\n' ) line_begin = true;
putchar( buffer[i] );
}
else if( std::fwrite( buffer, 1, size, stdout ) != (unsigned int)size )
{ show_error( "Write error", errno ); return 2; }
}
if( size < buffer_size ) break;
}
int retval = wait_for_child( grep_pid, GREP );
if( retval != 1 )
{ if( pid ) kill( pid, SIGTERM ); }
else
if( pid && wait_for_child( pid, "data feeder" ) != 0 ) retval = 2;
if( grep_list && retval == 0 )
std::printf( "%s\n", input_filename.c_str() );
if( close( infd ) != 0 )
{ show_close_error( "data feeder" ); return 2; }
if( close( fda[0] ) != 0 )
{ show_close_error( GREP ); return 2; }
return retval;
}
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