src/xzdec/xzdec.c

   1 ///////////////////////////////////////////////////////////////////////////////
   2 //
   3 /// \file       xzdec.c
   4 /// \brief      Simple single-threaded tool to uncompress .xz or .lzma files
   5 //
   6 //  Author:     Lasse Collin
   7 //
   8 //  This file has been put into the public domain.
   9 //  You can do whatever you want with this file.
  10 //
  11 ///////////////////////////////////////////////////////////////////////////////
  12
  13 #include "sysdefs.h"
  14 #include "lzma.h"
  15
  16 #include <stdarg.h>
  17 #include <errno.h>
  18 #include <stdio.h>
  19 #include <unistd.h>
  20
  21 #include "getopt.h"
  22 #include "tuklib_progname.h"
  23 #include "tuklib_exit.h"
  24
  25 #ifdef TUKLIB_DOSLIKE
  26 #       include <fcntl.h>
  27 #       include <io.h>
  28 #endif
  29
  30
  31 #ifdef LZMADEC
  32 #       define TOOL_FORMAT "lzma"
  33 #else
  34 #       define TOOL_FORMAT "xz"
  35 #endif
  36
  37
  38 /// Error messages are suppressed if this is zero, which is the case when
  39 /// --quiet has been given at least twice.
  40 static int display_errors = 2;
  41
  42
  43 static void lzma_attribute((__format__(__printf__, 1, 2)))
  44 my_errorf(const char *fmt, ...)
  45 {
  46         va_list ap;
  47         va_start(ap, fmt);
  48
  49         if (display_errors) {
  50                 fprintf(stderr, "%s: ", progname);
  51                 vfprintf(stderr, fmt, ap);
  52                 fprintf(stderr, "\n");
  53         }
  54
  55         va_end(ap);
  56         return;
  57 }
  58
  59
  60 static void lzma_attribute((__noreturn__))
  61 help(void)
  62 {
  63         printf(
  64 "Usage: %s [OPTION]... [FILE]...\n"
  65 "Decompress files in the ." TOOL_FORMAT " format to standard output.\n"
  66 "\n"
  67 "  -d, --decompress   (ignored, only decompression is supported)\n"
  68 "  -k, --keep         (ignored, files are never deleted)\n"
  69 "  -c, --stdout       (ignored, output is always written to standard output)\n"
  70 "  -q, --quiet        specify *twice* to suppress errors\n"
  71 "  -Q, --no-warn      (ignored, the exit status 2 is never used)\n"
  72 "  -h, --help         display this help and exit\n"
  73 "  -V, --version      display the version number and exit\n"
  74 "\n"
  75 "With no FILE, or when FILE is -, read standard input.\n"
  76 "\n"
  77 "Report bugs to <" PACKAGE_BUGREPORT "> (in English or Finnish).\n"
  78 PACKAGE_NAME " home page: <" PACKAGE_URL ">\n", progname);
  79
  80         tuklib_exit(EXIT_SUCCESS, EXIT_FAILURE, display_errors);
  81 }
  82
  83
  84 static void lzma_attribute((__noreturn__))
  85 version(void)
  86 {
  87         printf(TOOL_FORMAT "dec (" PACKAGE_NAME ") " LZMA_VERSION_STRING "\n"
  88                         "liblzma %s\n", lzma_version_string());
  89
  90         tuklib_exit(EXIT_SUCCESS, EXIT_FAILURE, display_errors);
  91 }
  92
  93
  94 /// Parses command line options.
  95 static void
  96 parse_options(int argc, char **argv)
  97 {
  98         static const char short_opts[] = "cdkM:hqQV";
  99         static const struct option long_opts[] = {
 100                 { "stdout",       no_argument,         NULL, 'c' },
 101                 { "to-stdout",    no_argument,         NULL, 'c' },
 102                 { "decompress",   no_argument,         NULL, 'd' },
 103                 { "uncompress",   no_argument,         NULL, 'd' },
 104                 { "keep",         no_argument,         NULL, 'k' },
 105                 { "quiet",        no_argument,         NULL, 'q' },
 106                 { "no-warn",      no_argument,         NULL, 'Q' },
 107                 { "help",         no_argument,         NULL, 'h' },
 108                 { "version",      no_argument,         NULL, 'V' },
 109                 { NULL,           0,                   NULL, 0   }
 110         };
 111
 112         int c;
 113
 114         while ((c = getopt_long(argc, argv, short_opts, long_opts, NULL))
 115                         != -1) {
 116                 switch (c) {
 117                 case 'c':
 118                 case 'd':
 119                 case 'k':
 120                 case 'Q':
 121                         break;
 122
 123                 case 'q':
 124                         if (display_errors > 0)
 125                                 --display_errors;
 126
 127                         break;
 128
 129                 case 'h':
 130                         help();
 131
 132                 case 'V':
 133                         version();
 134
 135                 default:
 136                         exit(EXIT_FAILURE);
 137                 }
 138         }
 139
 140         return;
 141 }
 142
 143
 144 static void
 145 uncompress(lzma_stream *strm, FILE *file, const char *filename)
 146 {
 147         lzma_ret ret;
 148
 149         // Initialize the decoder
 150 #ifdef LZMADEC
 151         ret = lzma_alone_decoder(strm, UINT64_MAX);
 152 #else
 153         ret = lzma_stream_decoder(strm, UINT64_MAX, LZMA_CONCATENATED);
 154 #endif
 155
 156         // The only reasonable error here is LZMA_MEM_ERROR.
 157         if (ret != LZMA_OK) {
 158                 my_errorf("%s", ret == LZMA_MEM_ERROR ? strerror(ENOMEM)
 159                                 : "Internal error (bug)");
 160                 exit(EXIT_FAILURE);
 161         }
 162
 163         // Input and output buffers
 164         uint8_t in_buf[BUFSIZ];
 165         uint8_t out_buf[BUFSIZ];
 166
 167         strm->avail_in = 0;
 168         strm->next_out = out_buf;
 169         strm->avail_out = BUFSIZ;
 170
 171         lzma_action action = LZMA_RUN;
 172
 173         while (true) {
 174                 if (strm->avail_in == 0) {
 175                         strm->next_in = in_buf;
 176                         strm->avail_in = fread(in_buf, 1, BUFSIZ, file);
 177
 178                         if (ferror(file)) {
 179                                 // POSIX says that fread() sets errno if
 180                                 // an error occurred. ferror() doesn't
 181                                 // touch errno.
 182                                 my_errorf("%s: Error reading input file: %s",
 183                                                 filename, strerror(errno));
 184                                 exit(EXIT_FAILURE);
 185                         }
 186
 187 #ifndef LZMADEC
 188                         // When using LZMA_CONCATENATED, we need to tell
 189                         // liblzma when it has got all the input.
 190                         if (feof(file))
 191                                 action = LZMA_FINISH;
 192 #endif
 193                 }
 194
 195                 ret = lzma_code(strm, action);
 196
 197                 // Write and check write error before checking decoder error.
 198                 // This way as much data as possible gets written to output
 199                 // even if decoder detected an error.
 200                 if (strm->avail_out == 0 || ret != LZMA_OK) {
 201                         const size_t write_size = BUFSIZ - strm->avail_out;
 202
 203                         if (fwrite(out_buf, 1, write_size, stdout)
 204                                         != write_size) {
 205                                 // Wouldn't be a surprise if writing to stderr
 206                                 // would fail too but at least try to show an
 207                                 // error message.
 208                                 my_errorf("Cannot write to standard output: "
 209                                                 "%s", strerror(errno));
 210                                 exit(EXIT_FAILURE);
 211                         }
 212
 213                         strm->next_out = out_buf;
 214                         strm->avail_out = BUFSIZ;
 215                 }
 216
 217                 if (ret != LZMA_OK) {
 218                         if (ret == LZMA_STREAM_END) {
 219 #ifdef LZMADEC
 220                                 // Check that there's no trailing garbage.
 221                                 if (strm->avail_in != 0
 222                                                 || fread(in_buf, 1, 1, file)
 223                                                         != 0
 224                                                 || !feof(file))
 225                                         ret = LZMA_DATA_ERROR;
 226                                 else
 227                                         return;
 228 #else
 229                                 // lzma_stream_decoder() already guarantees
 230                                 // that there's no trailing garbage.
 231                                 assert(strm->avail_in == 0);
 232                                 assert(action == LZMA_FINISH);
 233                                 assert(feof(file));
 234                                 return;
 235 #endif
 236                         }
 237
 238                         const char *msg;
 239                         switch (ret) {
 240                         case LZMA_MEM_ERROR:
 241                                 msg = strerror(ENOMEM);
 242                                 break;
 243
 244                         case LZMA_FORMAT_ERROR:
 245                                 msg = "File format not recognized";
 246                                 break;
 247
 248                         case LZMA_OPTIONS_ERROR:
 249                                 // FIXME: Better message?
 250                                 msg = "Unsupported compression options";
 251                                 break;
 252
 253                         case LZMA_DATA_ERROR:
 254                                 msg = "File is corrupt";
 255                                 break;
 256
 257                         case LZMA_BUF_ERROR:
 258                                 msg = "Unexpected end of input";
 259                                 break;
 260
 261                         default:
 262                                 msg = "Internal error (bug)";
 263                                 break;
 264                         }
 265
 266                         my_errorf("%s: %s", filename, msg);
 267                         exit(EXIT_FAILURE);
 268                 }
 269         }
 270 }
 271
 272
 273 int
 274 main(int argc, char **argv)
 275 {
 276         // Initialize progname which we will be used in error messages.
 277         tuklib_progname_init(argv);
 278
 279         // Parse the command line options.
 280         parse_options(argc, argv);
 281
 282         // The same lzma_stream is used for all files that we decode. This way
 283         // we don't need to reallocate memory for every file if they use same
 284         // compression settings.
 285         lzma_stream strm = LZMA_STREAM_INIT;
 286
 287         // Some systems require setting stdin and stdout to binary mode.
 288 #ifdef TUKLIB_DOSLIKE
 289         setmode(fileno(stdin), O_BINARY);
 290         setmode(fileno(stdout), O_BINARY);
 291 #endif
 292
 293         if (optind == argc) {
 294                 // No filenames given, decode from stdin.
 295                 uncompress(&strm, stdin, "(stdin)");
 296         } else {
 297                 // Loop through the filenames given on the command line.
 298                 do {
 299                         // "-" indicates stdin.
 300                         if (strcmp(argv[optind], "-") == 0) {
 301                                 uncompress(&strm, stdin, "(stdin)");
 302                         } else {
 303                                 FILE *file = fopen(argv[optind], "rb");
 304                                 if (file == NULL) {
 305                                         my_errorf("%s: %s", argv[optind],
 306                                                         strerror(errno));
 307                                         exit(EXIT_FAILURE);
 308                                 }
 309
 310                                 uncompress(&strm, file, argv[optind]);
 311                                 fclose(file);
 312                         }
 313                 } while (++optind < argc);
 314         }
 315
 316 #ifndef NDEBUG
 317         // Free the memory only when debugging. Freeing wastes some time,
 318         // but allows detecting possible memory leaks with Valgrind.
 319         lzma_end(&strm);
 320 #endif
 321
 322         tuklib_exit(EXIT_SUCCESS, EXIT_FAILURE, display_errors);
 323 }