util.c

   1 /* util.c -- utility functions for gzip support
   2
   3    Copyright (C) 1997-1999, 2001-2002, 2006, 2009-2024 Free Software
   4    Foundation, Inc.
   5    Copyright (C) 1992-1993 Jean-loup Gailly
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3, or (at your option)
  10    any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  19
  20 #include <config.h>
  21 #include <ctype.h>
  22 #include <errno.h>
  23 #include <limits.h>
  24 #include <unistd.h>
  25 #include <fcntl.h>
  26 #include <stdlib.h>
  27
  28 #include "tailor.h"
  29 #include "gzip.h"
  30 #include <dirname.h>
  31 #include <xalloc.h>
  32
  33 #ifndef EPIPE
  34 # define EPIPE 0
  35 #endif
  36
  37 static int write_buffer (int, voidp, unsigned int);
  38
  39 /* ========================================================================
  40  * Table of CRC-32's of all single-byte values (made by makecrc.c)
  41  */
  42 static const ulg crc_32_tab[] = {
  43   0x00000000L, 0x77073096L, 0xee0e612cL, 0x990951baL, 0x076dc419L,
  44   0x706af48fL, 0xe963a535L, 0x9e6495a3L, 0x0edb8832L, 0x79dcb8a4L,
  45   0xe0d5e91eL, 0x97d2d988L, 0x09b64c2bL, 0x7eb17cbdL, 0xe7b82d07L,
  46   0x90bf1d91L, 0x1db71064L, 0x6ab020f2L, 0xf3b97148L, 0x84be41deL,
  47   0x1adad47dL, 0x6ddde4ebL, 0xf4d4b551L, 0x83d385c7L, 0x136c9856L,
  48   0x646ba8c0L, 0xfd62f97aL, 0x8a65c9ecL, 0x14015c4fL, 0x63066cd9L,
  49   0xfa0f3d63L, 0x8d080df5L, 0x3b6e20c8L, 0x4c69105eL, 0xd56041e4L,
  50   0xa2677172L, 0x3c03e4d1L, 0x4b04d447L, 0xd20d85fdL, 0xa50ab56bL,
  51   0x35b5a8faL, 0x42b2986cL, 0xdbbbc9d6L, 0xacbcf940L, 0x32d86ce3L,
  52   0x45df5c75L, 0xdcd60dcfL, 0xabd13d59L, 0x26d930acL, 0x51de003aL,
  53   0xc8d75180L, 0xbfd06116L, 0x21b4f4b5L, 0x56b3c423L, 0xcfba9599L,
  54   0xb8bda50fL, 0x2802b89eL, 0x5f058808L, 0xc60cd9b2L, 0xb10be924L,
  55   0x2f6f7c87L, 0x58684c11L, 0xc1611dabL, 0xb6662d3dL, 0x76dc4190L,
  56   0x01db7106L, 0x98d220bcL, 0xefd5102aL, 0x71b18589L, 0x06b6b51fL,
  57   0x9fbfe4a5L, 0xe8b8d433L, 0x7807c9a2L, 0x0f00f934L, 0x9609a88eL,
  58   0xe10e9818L, 0x7f6a0dbbL, 0x086d3d2dL, 0x91646c97L, 0xe6635c01L,
  59   0x6b6b51f4L, 0x1c6c6162L, 0x856530d8L, 0xf262004eL, 0x6c0695edL,
  60   0x1b01a57bL, 0x8208f4c1L, 0xf50fc457L, 0x65b0d9c6L, 0x12b7e950L,
  61   0x8bbeb8eaL, 0xfcb9887cL, 0x62dd1ddfL, 0x15da2d49L, 0x8cd37cf3L,
  62   0xfbd44c65L, 0x4db26158L, 0x3ab551ceL, 0xa3bc0074L, 0xd4bb30e2L,
  63   0x4adfa541L, 0x3dd895d7L, 0xa4d1c46dL, 0xd3d6f4fbL, 0x4369e96aL,
  64   0x346ed9fcL, 0xad678846L, 0xda60b8d0L, 0x44042d73L, 0x33031de5L,
  65   0xaa0a4c5fL, 0xdd0d7cc9L, 0x5005713cL, 0x270241aaL, 0xbe0b1010L,
  66   0xc90c2086L, 0x5768b525L, 0x206f85b3L, 0xb966d409L, 0xce61e49fL,
  67   0x5edef90eL, 0x29d9c998L, 0xb0d09822L, 0xc7d7a8b4L, 0x59b33d17L,
  68   0x2eb40d81L, 0xb7bd5c3bL, 0xc0ba6cadL, 0xedb88320L, 0x9abfb3b6L,
  69   0x03b6e20cL, 0x74b1d29aL, 0xead54739L, 0x9dd277afL, 0x04db2615L,
  70   0x73dc1683L, 0xe3630b12L, 0x94643b84L, 0x0d6d6a3eL, 0x7a6a5aa8L,
  71   0xe40ecf0bL, 0x9309ff9dL, 0x0a00ae27L, 0x7d079eb1L, 0xf00f9344L,
  72   0x8708a3d2L, 0x1e01f268L, 0x6906c2feL, 0xf762575dL, 0x806567cbL,
  73   0x196c3671L, 0x6e6b06e7L, 0xfed41b76L, 0x89d32be0L, 0x10da7a5aL,
  74   0x67dd4accL, 0xf9b9df6fL, 0x8ebeeff9L, 0x17b7be43L, 0x60b08ed5L,
  75   0xd6d6a3e8L, 0xa1d1937eL, 0x38d8c2c4L, 0x4fdff252L, 0xd1bb67f1L,
  76   0xa6bc5767L, 0x3fb506ddL, 0x48b2364bL, 0xd80d2bdaL, 0xaf0a1b4cL,
  77   0x36034af6L, 0x41047a60L, 0xdf60efc3L, 0xa867df55L, 0x316e8eefL,
  78   0x4669be79L, 0xcb61b38cL, 0xbc66831aL, 0x256fd2a0L, 0x5268e236L,
  79   0xcc0c7795L, 0xbb0b4703L, 0x220216b9L, 0x5505262fL, 0xc5ba3bbeL,
  80   0xb2bd0b28L, 0x2bb45a92L, 0x5cb36a04L, 0xc2d7ffa7L, 0xb5d0cf31L,
  81   0x2cd99e8bL, 0x5bdeae1dL, 0x9b64c2b0L, 0xec63f226L, 0x756aa39cL,
  82   0x026d930aL, 0x9c0906a9L, 0xeb0e363fL, 0x72076785L, 0x05005713L,
  83   0x95bf4a82L, 0xe2b87a14L, 0x7bb12baeL, 0x0cb61b38L, 0x92d28e9bL,
  84   0xe5d5be0dL, 0x7cdcefb7L, 0x0bdbdf21L, 0x86d3d2d4L, 0xf1d4e242L,
  85   0x68ddb3f8L, 0x1fda836eL, 0x81be16cdL, 0xf6b9265bL, 0x6fb077e1L,
  86   0x18b74777L, 0x88085ae6L, 0xff0f6a70L, 0x66063bcaL, 0x11010b5cL,
  87   0x8f659effL, 0xf862ae69L, 0x616bffd3L, 0x166ccf45L, 0xa00ae278L,
  88   0xd70dd2eeL, 0x4e048354L, 0x3903b3c2L, 0xa7672661L, 0xd06016f7L,
  89   0x4969474dL, 0x3e6e77dbL, 0xaed16a4aL, 0xd9d65adcL, 0x40df0b66L,
  90   0x37d83bf0L, 0xa9bcae53L, 0xdebb9ec5L, 0x47b2cf7fL, 0x30b5ffe9L,
  91   0xbdbdf21cL, 0xcabac28aL, 0x53b39330L, 0x24b4a3a6L, 0xbad03605L,
  92   0xcdd70693L, 0x54de5729L, 0x23d967bfL, 0xb3667a2eL, 0xc4614ab8L,
  93   0x5d681b02L, 0x2a6f2b94L, 0xb40bbe37L, 0xc30c8ea1L, 0x5a05df1bL,
  94   0x2d02ef8dL
  95 };
  96
  97 /* Shift register contents.  */
  98 static ulg crc = 0xffffffffL;
  99
 100 /* ===========================================================================
 101  * Copy input to output unchanged: zcat == cat with --force.
 102  * IN assertion: insize bytes have already been read in inbuf and inptr bytes
 103  * already processed or copied.
 104  * 'in' and 'out' are the input and output file descriptors.
 105  */
 106 int
 107 copy (int in, int out)
 108 {
 109     int got;
 110
 111     errno = 0;
 112     while (insize > inptr) {
 113         write_buf(out, (char*)inbuf + inptr, insize - inptr);
 114         got = read_buffer (in, (char *) inbuf, INBUFSIZ);
 115         if (got == -1)
 116             read_error();
 117         bytes_in += got;
 118         insize = (unsigned)got;
 119         inptr = 0;
 120     }
 121     return OK;
 122 }
 123
 124 /* ===========================================================================
 125  * Run a set of bytes through the crc shift register.  If s is a NULL
 126  * pointer, then initialize the crc shift register contents instead.
 127  * Return the current crc in either case.
 128  * S points to N bytes to pump through.
 129  */
 130 ulg
 131 updcrc (uch const *s, unsigned n)
 132 {
 133     register ulg c;         /* temporary variable */
 134
 135     if (s == NULL) {
 136         c = 0xffffffffL;
 137     } else {
 138         c = crc;
 139         if (n) do {
 140             c = crc_32_tab[((int)c ^ (*s++)) & 0xff] ^ (c >> 8);
 141         } while (--n);
 142     }
 143     crc = c;
 144     return c ^ 0xffffffffL;       /* (instead of ~c for 64-bit machines) */
 145 }
 146
 147 /* Return a current CRC value.  */
 148 ulg
 149 getcrc ()
 150 {
 151   return crc ^ 0xffffffffL;
 152 }
 153
 154 #ifdef IBM_Z_DFLTCC
 155 /* Set a new CRC value.  */
 156 void
 157 setcrc (ulg c)
 158 {
 159   crc = c ^ 0xffffffffL;
 160 }
 161 #endif
 162
 163 /* ===========================================================================
 164  * Clear input and output buffers
 165  */
 166 void clear_bufs()
 167 {
 168     outcnt = 0;
 169     insize = inptr = 0;
 170     bytes_in = bytes_out = 0L;
 171 }
 172
 173 /* ===========================================================================
 174  * Fill the input buffer. This is called only when the buffer is empty.
 175  * EOF_OK is set if EOF acceptable as a result.
 176  */
 177 int
 178 fill_inbuf (int eof_ok)
 179 {
 180     int len;
 181
 182     /* Read as much as possible */
 183     insize = 0;
 184     do {
 185         len = read_buffer (ifd, (char *) inbuf + insize, INBUFSIZ - insize);
 186         if (len == 0) break;
 187         if (len == -1) {
 188           read_error();
 189           break;
 190         }
 191         insize += len;
 192     } while (insize < INBUFSIZ);
 193
 194     if (insize == 0) {
 195         if (eof_ok) return EOF;
 196         flush_window();
 197         errno = 0;
 198         read_error();
 199     }
 200     bytes_in += (off_t)insize;
 201     inptr = 1;
 202     return inbuf[0];
 203 }
 204
 205 /* Like the standard read function, except do not attempt to read more
 206    than INT_MAX bytes at a time.  */
 207 int
 208 read_buffer (int fd, voidp buf, unsigned int cnt)
 209 {
 210   int len;
 211   if (INT_MAX < cnt)
 212     cnt = INT_MAX;
 213   len = read (fd, buf, cnt);
 214
 215 #if defined F_SETFL && O_NONBLOCK && defined EAGAIN
 216   /* Input files are opened O_NONBLOCK for security reasons.  On some
 217      file systems this can cause read to fail with errno == EAGAIN.  */
 218   if (len < 0 && errno == EAGAIN)
 219     {
 220       int flags = fcntl (fd, F_GETFL);
 221       if (0 <= flags)
 222         {
 223           if (! (flags & O_NONBLOCK))
 224             errno = EAGAIN;
 225           else if (fcntl (fd, F_SETFL, flags & ~O_NONBLOCK) != -1)
 226             len = read (fd, buf, cnt);
 227         }
 228     }
 229 #endif
 230
 231   return len;
 232 }
 233
 234 /* Likewise for 'write'.  */
 235 static int
 236 write_buffer (int fd, voidp buf, unsigned int cnt)
 237 {
 238   if (INT_MAX < cnt)
 239     cnt = INT_MAX;
 240   return write (fd, buf, cnt);
 241 }
 242
 243 /* ===========================================================================
 244  * Write the output buffer outbuf[0..outcnt-1] and update bytes_out.
 245  * (used for the compressed data only)
 246  */
 247 void flush_outbuf()
 248 {
 249     if (outcnt == 0) return;
 250
 251     write_buf (ofd, outbuf, outcnt);
 252     outcnt = 0;
 253 }
 254
 255 /* ===========================================================================
 256  * Write the output window window[0..outcnt-1] and update crc and bytes_out.
 257  * (Used for the decompressed data only.)
 258  */
 259 void flush_window()
 260 {
 261     if (outcnt == 0) return;
 262     updcrc(window, outcnt);
 263
 264     write_buf (ofd, window, outcnt);
 265     outcnt = 0;
 266 }
 267
 268 /* ===========================================================================
 269  * Update the count of output bytes.  If testing, do not do any
 270  * output.  Otherwise, write the buffer, checking for errors.
 271  */
 272 void
 273 write_buf (int fd, voidp buf, unsigned  cnt)
 274 {
 275     unsigned  n;
 276
 277     bytes_out += cnt;
 278     if (test)
 279       return;
 280
 281     while ((n = write_buffer (fd, buf, cnt)) != cnt) {
 282         if (n == (unsigned)(-1)) {
 283             write_error();
 284         }
 285         cnt -= n;
 286         buf = (voidp)((char*)buf+n);
 287     }
 288 }
 289
 290 /* ========================================================================
 291  * Put string s in lower case, return s.
 292  */
 293 char *
 294 strlwr (char *s)
 295 {
 296     char *t;
 297     for (t = s; *t; t++)
 298       *t = tolow ((unsigned char) *t);
 299     return s;
 300 }
 301
 302 /* ========================================================================
 303  * Return the base name of a file (remove any directory prefix and
 304  * any version suffix). For systems with file names that are not
 305  * case sensitive, force the base name to lower case.
 306  */
 307 char *
 308 gzip_base_name (char *fname)
 309 {
 310     fname = last_component (fname);
 311     if (casemap('A') == 'a') strlwr(fname);
 312     return fname;
 313 }
 314
 315 /* ========================================================================
 316  * Unlink a file, working around the unlink readonly bug (if present).
 317  */
 318 int
 319 xunlink (char *filename)
 320 {
 321   int r = unlink (filename);
 322
 323 #ifdef UNLINK_READONLY_BUG
 324   if (r != 0)
 325     {
 326       int e = errno;
 327       if (chmod (filename, S_IWUSR) != 0)
 328         {
 329           errno = e;
 330           return -1;
 331         }
 332
 333       r = unlink (filename);
 334     }
 335 #endif
 336
 337   return r;
 338 }
 339
 340 #ifdef NO_MULTIPLE_DOTS
 341 /* ========================================================================
 342  * Make a file name legal for file systems not allowing file names with
 343  * multiple dots or starting with a dot (such as MSDOS), by changing
 344  * all dots except the last one into underlines.  A target dependent
 345  * function can be used instead of this simple function by defining the macro
 346  * MAKE_LEGAL_NAME in tailor.h and providing the function in a target
 347  * dependent module.
 348  */
 349 void
 350 make_simple_name (char *name)
 351 {
 352     char *p = strrchr(name, '.');
 353     if (p == NULL) return;
 354     if (p == name) p++;
 355     do {
 356         if (*--p == '.') *p = '_';
 357     } while (p != name);
 358 }
 359 #endif
 360
 361 /* Convert the value of the environment variable ENVVAR_NAME
 362    to a newly allocated argument vector, and set *ARGCP and *ARGVP
 363    to the number of arguments and to the vector, respectively.
 364    Make the new vector's zeroth element equal to the old **ARGVP.
 365    Return a pointer to the newly allocated string storage.
 366
 367    If the vector would be empty, do not allocate storage,
 368    do not set *ARGCP and *ARGVP, and return NULL.  */
 369
 370 #define SEPARATOR       " \t"   /* separators in env variable */
 371
 372 char *add_envopt(
 373     int *argcp,          /* pointer to argc */
 374     char ***argvp,       /* pointer to argv */
 375     char const *envvar_name) /* name of environment variable */
 376 {
 377     char *p;             /* running pointer through env variable */
 378     char **oargv;        /* runs through old argv array */
 379     char **nargv;        /* runs through new argv array */
 380     int  nargc = 0;      /* number of arguments in env variable */
 381     char *env_val;
 382
 383     env_val = getenv(envvar_name);
 384     if (env_val == NULL) return NULL;
 385
 386     env_val = xstrdup (env_val);
 387
 388     for (p = env_val; *p; nargc++ ) {        /* move through env_val */
 389         p += strspn(p, SEPARATOR);           /* skip leading separators */
 390         if (*p == '\0') break;
 391
 392         p += strcspn(p, SEPARATOR);          /* find end of word */
 393         if (*p) *p++ = '\0';                 /* mark it */
 394     }
 395     if (nargc == 0) {
 396         free(env_val);
 397         return NULL;
 398     }
 399     *argcp = nargc + 1;
 400     /* Allocate the new argv array, with an extra element just in case
 401      * the original arg list did not end with a NULL.
 402      */
 403     nargv = xcalloc (*argcp + 1, sizeof (char *));
 404     oargv  = *argvp;
 405     *argvp = nargv;
 406
 407     /* Copy the program name first */
 408     *nargv++ = *oargv;
 409
 410     /* Then copy the environment args */
 411     for (p = env_val; nargc > 0; nargc--) {
 412         p += strspn(p, SEPARATOR);           /* skip separators */
 413         *(nargv++) = p;                      /* store start */
 414         while (*p++) ;                       /* skip over word */
 415     }
 416
 417     *nargv = NULL;
 418     return env_val;
 419 }
 420
 421 /* ========================================================================
 422  * Error handlers.
 423  */
 424 void
 425 gzip_error (char const *m)
 426 {
 427     fprintf (stderr, "\n%s: %s: %s\n", program_name, ifname, m);
 428     abort_gzip();
 429 }
 430
 431 void
 432 xalloc_die ()
 433 {
 434   fprintf (stderr, "\n%s: memory_exhausted\n", program_name);
 435   abort_gzip ();
 436 }
 437
 438 void warning (char const *m)
 439 {
 440     WARN ((stderr, "%s: %s: warning: %s\n", program_name, ifname, m));
 441 }
 442
 443 void read_error()
 444 {
 445     fprintf (stderr, "\n%s: %s: %s\n",
 446              program_name, ifname,
 447              errno ? strerror (errno) : "unexpected end of file");
 448     abort_gzip();
 449 }
 450
 451 void write_error()
 452 {
 453   int exitcode = errno == EPIPE ? WARNING : ERROR;
 454   if (! (exitcode == WARNING && quiet))
 455     fprintf (stderr, "\n%s: %s: %s\n", program_name, ofname, strerror (errno));
 456   finish_up_gzip (exitcode);
 457 }
 458
 459 /* ========================================================================
 460  * Display compression ratio on the given stream on 6 characters.
 461  */
 462 void
 463 display_ratio (off_t num, off_t den, FILE *file)
 464 {
 465     fprintf(file, "%5.1f%%", den == 0 ? 0 : 100.0 * num / den);
 466 }