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Diffstat (limited to 'zgrep.cc')
| -rw-r--r-- | zgrep.cc | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/zgrep.cc b/zgrep.cc new file mode 100644 index 0000000..b1c18b4 --- /dev/null +++ b/zgrep.cc @@ -0,0 +1,159 @@ +/* Zgrep - search compressed files for a regular expression + Copyright (C) 2010 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_error( "Can't exec `grep'." ); + _exit( 2 ); + } + // parent + if( grep_pid < 0 ) + { show_error( "Can't fork `grep'", errno ); return 2; } + int retval = 0; + if( pid && wait_for_child( pid, "data feeder" ) != 0 ) retval = 2; + if( wait_for_child( grep_pid, "grep" ) != 0 ) retval = 2; + if( close( infd ) != 0 ) + { show_error( "Can't close output of data feeder", errno ); 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_error( "Can't exec `grep'." ); + _exit( 2 ); + } + // parent + close( fda[1] ); + if( grep_pid < 0 ) + { show_error( "Can't fork `grep'", errno ); 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 = 0; + if( pid && wait_for_child( pid, "data feeder" ) != 0 ) retval = 2; + if( wait_for_child( grep_pid, "grep" ) != 0 ) retval = 2; + if( grep_list && retval == 0 ) + std::printf( "%s\n", input_filename.c_str() ); + if( close( infd ) != 0 ) + { show_error( "Can't close output of data feeder", errno ); return 2; } + if( close( fda[0] ) != 0 ) + { show_error( "Can't close output of grep", errno ); return 2; } + return retval; + } |