/* Ztest - verify the integrity of compressed files
   Copyright (C) 2010-2023 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 <climits>
#include <csignal>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <list>
#include <string>
#include <vector>
#include <dirent.h>
#include <fcntl.h>
#include <stdint.h>
#include <unistd.h>
#include <sys/stat.h>
#if defined __MSVCRT__ || defined __OS2__
#include <io.h>
#endif

#include "arg_parser.h"
#include "rc.h"
#include "zutils.h"

#ifndef O_BINARY
#define O_BINARY 0
#endif


namespace {

#include "recursive.cc"

void show_help()
  {
  std::printf( "ztest verifies the integrity of the compressed files specified. It\n"
               "also warns if an uncompressed file has a compressed file name extension, or\n"
               "if a compressed file has a wrong compressed extension. Uncompressed files\n"
               "are otherwise ignored. If a file is specified as '-', the integrity of\n"
               "compressed data read from standard input is verified. Data read from\n"
               "standard input must be all in the same compressed format. If a file fails to\n"
               "decompress, does not exist, can't be opened, or is a terminal, ztest\n"
               "continues verifying the rest of the files. A final diagnostic is shown at\n"
               "verbosity level 1 or higher if any file fails the test when testing multiple\n"
               "files.\n"
               "\nIf no files are specified, recursive searches examine the current\n"
               "working directory, and nonrecursive searches read standard input.\n"
               "\nThe formats supported are bzip2, gzip, lzip, xz, and zstd.\n"
               "\nNote that error detection in the xz format is broken. First, some xz\n"
               "files lack integrity information. Second, not all xz decompressors can\n"
               "verify the integrity of all xz files. Third, section 2.1.1.2 'Stream\n"
               "Flags' of the xz format specification allows xz decompressors to produce\n"
               "garbage output without issuing any warning. Therefore, xz files can't\n"
               "always be verified as reliably as files in the other formats can.\n"
               "\nUsage: ztest [options] [files]\n"
               "\nExit status is 0 if all compressed files verify OK, 1 if environmental\n"
               "problems (file not found, invalid command line options, I/O errors, etc),\n"
               "2 if any compressed file is corrupt or invalid, or if any file has an\n"
               "incorrect file name extension.\n"
               "\nOptions:\n"
               "  -h, --help                   display this help and exit\n"
               "  -V, --version                output version information and exit\n"
               "  -M, --format=<list>          process only the formats in <list>\n"
               "  -N, --no-rcfile              don't read runtime configuration file\n"
               "  -O, --force-format=<fmt>     force the input format\n"
               "  -q, --quiet                  suppress all messages\n"
               "  -r, --recursive              operate recursively on directories\n"
               "  -R, --dereference-recursive  recursively follow symbolic links\n"
               "  -v, --verbose                be verbose (a 2nd -v gives more)\n"
               "      --bz2=<command>          set compressor and options for bzip2 format\n"
               "      --gz=<command>           set compressor and options for gzip format\n"
               "      --lz=<command>           set compressor and options for lzip format\n"
               "      --xz=<command>           set compressor and options for xz format\n"
               "      --zst=<command>          set compressor and options for zstd format\n"
               "\nValid formats for options '-M' and '-O' are 'bz2', 'gz', 'lz', 'xz', and 'zst'.\n" );
  show_help_addr();
  }


int open_instream( const std::string & input_filename )
  {
  const int infd = open( input_filename.c_str(), O_RDONLY | O_BINARY );
  if( infd < 0 )
    show_file_error( input_filename.c_str(), "Can't open input file", errno );
  return infd;
  }


int ztest_stdin( const int infd, int format_index,
                 const std::vector< const char * > & ztest_args )
  {
  uint8_t magic_data[magic_buf_size];
  int magic_size = 0;
  if( format_index < 0 )
    format_index = test_format( infd, magic_data, &magic_size );
  const char * const compressor_name = get_compressor_name( format_index );
  if( !compressor_name )
    { show_error( "Unknown data format read from stdin." ); return 2; }
  int fda[2];				// pipe from feeder
  if( pipe( fda ) < 0 )
    { show_error( "Can't create pipe", errno ); return 1; }

  const pid_t pid = fork();
  if( pid == 0 )			// child1 (compressor feeder)
    {
    if( close( fda[0] ) != 0 ||
        !feed_data( "-", infd, fda[1], magic_data, magic_size ) ) _exit( 1 );
    if( close( fda[1] ) != 0 ) { show_close_error(); _exit( 1 ); }
    _exit( 0 );
    }
  if( pid < 0 )				// parent
    { show_fork_error( "data feeder" ); return 1; }

  const pid_t pid2 = fork();
  if( pid2 == 0 )			// child2 (compressor)
    {
    if( dup2( fda[0], STDIN_FILENO ) >= 0 &&
        close( fda[0] ) == 0 && close( fda[1] ) == 0 )
      {
      const std::vector< std::string > & compressor_args =
        get_compressor_args( format_index );
      const int size = compressor_args.size();
      const int size2 = ztest_args.size();
      const char ** const argv = new const char *[size+size2+3];
      argv[0] = compressor_name;
      for( int i = 0; i < size; ++i )
        argv[i+1] = compressor_args[i].c_str();
      for( int i = 0; i < size2; ++i )
        argv[i+size+1] = ztest_args[i];
      argv[size+size2+1] = "-t";
      argv[size+size2+2] = 0;
      execvp( argv[0], (char **)argv );
      }
    show_exec_error( compressor_name );
    _exit( 1 );
    }
  if( pid2 < 0 )			// parent
    { show_fork_error( compressor_name ); return 1; }

  close( fda[0] ); close( fda[1] );
  const bool isgzxz = ( format_index == fmt_gz || format_index == fmt_xz );
  int retval = wait_for_child( pid2, compressor_name, 1, isgzxz );
  if( retval == 0 && wait_for_child( pid, "data feeder" ) != 0 )
    retval = 1;
  return retval;
  }


int ztest_file( const int infd, int format_index,
                const std::string & input_filename,
                const std::vector< const char * > & ztest_args )
  {
  // bzip2, gzip, and lzip are the primary formats. xz and zstd are optional.
  static int disable_xz = -1;				// tri-state bool
  static int disable_zst = -1;				// tri-state bool
  uint8_t magic_data[magic_buf_size];
  int magic_size = 0;
  const int format_index_e = test_extension( input_filename );
  if( format_index < 0 )
    format_index = test_format( infd, magic_data, &magic_size );
  const char * const compressor_name = get_compressor_name( format_index );
  if( !compressor_name )
    {
    if( format_index < 0 && format_index_e >= 0 )
      { show_file_error( input_filename.c_str(),
        "Uncompressed file has compressed extension." ); return 2; }
    return 0;				// ignore this file
    }
  if( format_index == fmt_xz )
    {
    if( disable_xz < 0 )
      {
      std::string command( compressor_name ); command += " -V > /dev/null 2>&1";
      disable_xz = ( std::system( command.c_str() ) != 0 );
      if( disable_xz && verbosity >= 2 )
        std::fprintf( stderr, "%s: '%s' not found. Ignoring xz files.\n",
                      program_name, compressor_name );
      }
    if( disable_xz ) return 0;		// ignore this file if no xz installed
    }
  else if( format_index == fmt_zst )
    {
    if( disable_zst < 0 )
      {
      std::string command( compressor_name ); command += " -V > /dev/null 2>&1";
      disable_zst = ( std::system( command.c_str() ) != 0 );
      if( disable_zst && verbosity >= 2 )
        std::fprintf( stderr, "%s: '%s' not found. Ignoring zstd files.\n",
                      program_name, compressor_name );
      }
    if( disable_zst ) return 0;		// ignore this file if no zstd installed
    }

  const pid_t pid = fork();

  if( pid == 0 )			// child (compressor)
    {
    const std::vector< std::string > & compressor_args =
      get_compressor_args( format_index );
    const int size = compressor_args.size();
    const int size2 = ztest_args.size();
    const char ** const argv = new const char *[size+size2+5];
    argv[0] = compressor_name;
    for( int i = 0; i < size; ++i )
      argv[i+1] = compressor_args[i].c_str();
    for( int i = 0; i < size2; ++i )
      argv[i+size+1] = ztest_args[i];
    argv[size+size2+1] = "-t";
    argv[size+size2+2] = "--";
    argv[size+size2+3] = input_filename.c_str();
    argv[size+size2+4] = 0;
    execvp( argv[0], (char **)argv );
    show_exec_error( compressor_name );
    _exit( 1 );
    }
  if( pid < 0 )				// parent
    { show_fork_error( compressor_name ); return 1; }

  const bool isgzxz = ( format_index == fmt_gz || format_index == fmt_xz );
  int retval =  wait_for_child( pid, compressor_name, 1, isgzxz );
  if( retval == 0 && format_index >= 0 && format_index_e >= 0 &&
      format_index != format_index_e )
    { show_file_error( input_filename.c_str(),
      "Compressed file has wrong compressed extension." ); retval = 2; }
  return retval;
  }

} // end namespace


int main( const int argc, const char * const argv[] )
  {
  enum { bz2_opt = 256, gz_opt, lz_opt, xz_opt, zst_opt };
  int format_index = -1;			// undefined
  int recursive = 0;				// 1 = '-r', 2 = '-R'
  std::list< std::string > filenames;
  std::vector< const char * > ztest_args;	// args to ztest, maybe empty
  program_name = "ztest";
  invocation_name = ( argc > 0 ) ? argv[0] : program_name;

  const Arg_parser::Option options[] =
    {
    { 'h', "help",                  Arg_parser::no  },
    { 'M', "format",                Arg_parser::yes },
    { 'N', "no-rcfile",             Arg_parser::no  },
    { 'O', "force-format",          Arg_parser::yes },
    { 'q', "quiet",                 Arg_parser::no  },
    { 'r', "recursive",             Arg_parser::no  },
    { 'R', "dereference-recursive", Arg_parser::no  },
    { 'v', "verbose",               Arg_parser::no  },
    { 'V', "version",               Arg_parser::no  },
    { bz2_opt, "bz2",               Arg_parser::yes },
    { gz_opt,  "gz",                Arg_parser::yes },
    { lz_opt,  "lz",                Arg_parser::yes },
    { xz_opt,  "xz",                Arg_parser::yes },
    { zst_opt, "zst",               Arg_parser::yes },
    {  0,   0,                      Arg_parser::no  } };

  const Arg_parser parser( argc, argv, options );
  if( parser.error().size() )				// bad option
    { show_error( parser.error().c_str(), 0, true ); return 1; }

  maybe_process_config_file( parser );

  int argind = 0;
  for( ; argind < parser.arguments(); ++argind )
    {
    const int code = parser.code( argind );
    if( !code ) break;					// no more options
    const char * const pn = parser.parsed_name( argind ).c_str();
    const std::string & arg = parser.argument( argind );
    switch( code )
      {
      case 'h': show_help(); return 0;
      case 'M': parse_format_list( arg, pn ); break;
      case 'N': break;
      case 'O': format_index = parse_format_type( arg, pn, false ); break;
      case 'q': verbosity = -1; ztest_args.push_back( "-q" ); break;
      case 'r': recursive = 1; break;
      case 'R': recursive = 2; break;
      case 'v': if( verbosity < 4 ) ++verbosity;
                ztest_args.push_back( "-v" ); break;
      case 'V': show_version(); return 0;
      case bz2_opt: parse_compressor( arg, pn, fmt_bz2, 1 ); break;
      case gz_opt: parse_compressor( arg, pn, fmt_gz, 1 ); break;
      case lz_opt: parse_compressor( arg, pn, fmt_lz, 1 ); break;
      case xz_opt: parse_compressor( arg, pn, fmt_xz, 1 ); break;
      case zst_opt: parse_compressor( arg, pn, fmt_zst, 1 ); break;
      default : internal_error( "uncaught option." );
      }
    } // end process options

#if defined __MSVCRT__ || defined __OS2__
  setmode( STDIN_FILENO, O_BINARY );
  setmode( STDOUT_FILENO, O_BINARY );
#endif

  for( ; argind < parser.arguments(); ++argind )
    filenames.push_back( parser.argument( argind ) );

  if( filenames.empty() ) filenames.push_back( recursive ? "." : "-" );

  std::string input_filename;
  int files_tested = 0, failed_tests = 0;
  int retval = 0;
  bool error = false;
  bool stdin_used = false;
  while( next_filename( filenames, input_filename, error, recursive ) )
    {
    int infd;
    if( input_filename == "." )
      {
      if( stdin_used ) continue; else stdin_used = true;
      infd = STDIN_FILENO; input_filename = "-";
      }
    else
      {
      infd = open_instream( input_filename );
      if( infd < 0 ) { error = true; continue; }
      }

    if( isatty( infd ) )			// for example /dev/tty
      {
      show_file_error( name_or_stdin( input_filename.c_str() ),
                       "I won't read compressed data from a terminal." );
      close( infd ); error = true; continue;
      }

    int tmp;
    if( infd == STDIN_FILENO )
      tmp = ztest_stdin( infd, format_index, ztest_args );
    else tmp = ztest_file( infd, format_index, input_filename, ztest_args );
    if( tmp > retval ) retval = tmp;
    ++files_tested; if( tmp ) ++failed_tests;

    if( close( infd ) != 0 )
      { show_file_error( input_filename.c_str(), "Error closing input file",
                         errno ); error = true; }
    }

  if( std::fclose( stdout ) != 0 )	// in case decompressor writes to stdout
    {
    show_error( "Error closing stdout", errno );
    error = true;
    }
  if( error && retval == 0 ) retval = 1;
  if( failed_tests > 0 && verbosity >= 1 && files_tested > 1 )
    std::fprintf( stderr, "%s: warning: %d %s failed the test.\n",
                  program_name, failed_tests,
                  ( failed_tests == 1 ) ? "file" : "files" );
  return retval;
  }