util.c

   1 /* util.c -- utility functions for gzip support
   2
   3    Copyright (C) 1997-1999, 2001-2002, 2006, 2009-2022 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, write to the Free Software Foundation,
  19    Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
  20
  21 #include <config.h>
  22 #include <ctype.h>
  23 #include <errno.h>
  24 #include <limits.h>
  25 #include <unistd.h>
  26 #include <fcntl.h>
  27 #include <stdlib.h>
  28 #include <errno.h>
  29
  30 #include "tailor.h"
  31 #include "gzip.h"
  32 #include <dirname.h>
  33 #include <xalloc.h>
  34
  35 #ifndef CHAR_BIT
  36 #  define CHAR_BIT 8
  37 #endif
  38
  39 static int write_buffer (int, voidp, unsigned int);
  40
  41 /* ========================================================================
  42  * Table of CRC-32's of all single-byte values (made by makecrc.c)
  43  */
  44 static const ulg crc_32_tab[] = {
  45   0x00000000L, 0x77073096L, 0xee0e612cL, 0x990951baL, 0x076dc419L,
  46   0x706af48fL, 0xe963a535L, 0x9e6495a3L, 0x0edb8832L, 0x79dcb8a4L,
  47   0xe0d5e91eL, 0x97d2d988L, 0x09b64c2bL, 0x7eb17cbdL, 0xe7b82d07L,
  48   0x90bf1d91L, 0x1db71064L, 0x6ab020f2L, 0xf3b97148L, 0x84be41deL,
  49   0x1adad47dL, 0x6ddde4ebL, 0xf4d4b551L, 0x83d385c7L, 0x136c9856L,
  50   0x646ba8c0L, 0xfd62f97aL, 0x8a65c9ecL, 0x14015c4fL, 0x63066cd9L,
  51   0xfa0f3d63L, 0x8d080df5L, 0x3b6e20c8L, 0x4c69105eL, 0xd56041e4L,
  52   0xa2677172L, 0x3c03e4d1L, 0x4b04d447L, 0xd20d85fdL, 0xa50ab56bL,
  53   0x35b5a8faL, 0x42b2986cL, 0xdbbbc9d6L, 0xacbcf940L, 0x32d86ce3L,
  54   0x45df5c75L, 0xdcd60dcfL, 0xabd13d59L, 0x26d930acL, 0x51de003aL,
  55   0xc8d75180L, 0xbfd06116L, 0x21b4f4b5L, 0x56b3c423L, 0xcfba9599L,
  56   0xb8bda50fL, 0x2802b89eL, 0x5f058808L, 0xc60cd9b2L, 0xb10be924L,
  57   0x2f6f7c87L, 0x58684c11L, 0xc1611dabL, 0xb6662d3dL, 0x76dc4190L,
  58   0x01db7106L, 0x98d220bcL, 0xefd5102aL, 0x71b18589L, 0x06b6b51fL,
  59   0x9fbfe4a5L, 0xe8b8d433L, 0x7807c9a2L, 0x0f00f934L, 0x9609a88eL,
  60   0xe10e9818L, 0x7f6a0dbbL, 0x086d3d2dL, 0x91646c97L, 0xe6635c01L,
  61   0x6b6b51f4L, 0x1c6c6162L, 0x856530d8L, 0xf262004eL, 0x6c0695edL,
  62   0x1b01a57bL, 0x8208f4c1L, 0xf50fc457L, 0x65b0d9c6L, 0x12b7e950L,
  63   0x8bbeb8eaL, 0xfcb9887cL, 0x62dd1ddfL, 0x15da2d49L, 0x8cd37cf3L,
  64   0xfbd44c65L, 0x4db26158L, 0x3ab551ceL, 0xa3bc0074L, 0xd4bb30e2L,
  65   0x4adfa541L, 0x3dd895d7L, 0xa4d1c46dL, 0xd3d6f4fbL, 0x4369e96aL,
  66   0x346ed9fcL, 0xad678846L, 0xda60b8d0L, 0x44042d73L, 0x33031de5L,
  67   0xaa0a4c5fL, 0xdd0d7cc9L, 0x5005713cL, 0x270241aaL, 0xbe0b1010L,
  68   0xc90c2086L, 0x5768b525L, 0x206f85b3L, 0xb966d409L, 0xce61e49fL,
  69   0x5edef90eL, 0x29d9c998L, 0xb0d09822L, 0xc7d7a8b4L, 0x59b33d17L,
  70   0x2eb40d81L, 0xb7bd5c3bL, 0xc0ba6cadL, 0xedb88320L, 0x9abfb3b6L,
  71   0x03b6e20cL, 0x74b1d29aL, 0xead54739L, 0x9dd277afL, 0x04db2615L,
  72   0x73dc1683L, 0xe3630b12L, 0x94643b84L, 0x0d6d6a3eL, 0x7a6a5aa8L,
  73   0xe40ecf0bL, 0x9309ff9dL, 0x0a00ae27L, 0x7d079eb1L, 0xf00f9344L,
  74   0x8708a3d2L, 0x1e01f268L, 0x6906c2feL, 0xf762575dL, 0x806567cbL,
  75   0x196c3671L, 0x6e6b06e7L, 0xfed41b76L, 0x89d32be0L, 0x10da7a5aL,
  76   0x67dd4accL, 0xf9b9df6fL, 0x8ebeeff9L, 0x17b7be43L, 0x60b08ed5L,
  77   0xd6d6a3e8L, 0xa1d1937eL, 0x38d8c2c4L, 0x4fdff252L, 0xd1bb67f1L,
  78   0xa6bc5767L, 0x3fb506ddL, 0x48b2364bL, 0xd80d2bdaL, 0xaf0a1b4cL,
  79   0x36034af6L, 0x41047a60L, 0xdf60efc3L, 0xa867df55L, 0x316e8eefL,
  80   0x4669be79L, 0xcb61b38cL, 0xbc66831aL, 0x256fd2a0L, 0x5268e236L,
  81   0xcc0c7795L, 0xbb0b4703L, 0x220216b9L, 0x5505262fL, 0xc5ba3bbeL,
  82   0xb2bd0b28L, 0x2bb45a92L, 0x5cb36a04L, 0xc2d7ffa7L, 0xb5d0cf31L,
  83   0x2cd99e8bL, 0x5bdeae1dL, 0x9b64c2b0L, 0xec63f226L, 0x756aa39cL,
  84   0x026d930aL, 0x9c0906a9L, 0xeb0e363fL, 0x72076785L, 0x05005713L,
  85   0x95bf4a82L, 0xe2b87a14L, 0x7bb12baeL, 0x0cb61b38L, 0x92d28e9bL,
  86   0xe5d5be0dL, 0x7cdcefb7L, 0x0bdbdf21L, 0x86d3d2d4L, 0xf1d4e242L,
  87   0x68ddb3f8L, 0x1fda836eL, 0x81be16cdL, 0xf6b9265bL, 0x6fb077e1L,
  88   0x18b74777L, 0x88085ae6L, 0xff0f6a70L, 0x66063bcaL, 0x11010b5cL,
  89   0x8f659effL, 0xf862ae69L, 0x616bffd3L, 0x166ccf45L, 0xa00ae278L,
  90   0xd70dd2eeL, 0x4e048354L, 0x3903b3c2L, 0xa7672661L, 0xd06016f7L,
  91   0x4969474dL, 0x3e6e77dbL, 0xaed16a4aL, 0xd9d65adcL, 0x40df0b66L,
  92   0x37d83bf0L, 0xa9bcae53L, 0xdebb9ec5L, 0x47b2cf7fL, 0x30b5ffe9L,
  93   0xbdbdf21cL, 0xcabac28aL, 0x53b39330L, 0x24b4a3a6L, 0xbad03605L,
  94   0xcdd70693L, 0x54de5729L, 0x23d967bfL, 0xb3667a2eL, 0xc4614ab8L,
  95   0x5d681b02L, 0x2a6f2b94L, 0xb40bbe37L, 0xc30c8ea1L, 0x5a05df1bL,
  96   0x2d02ef8dL
  97 };
  98
  99 /* Shift register contents.  */
 100 static ulg crc = 0xffffffffL;
 101
 102 /* ===========================================================================
 103  * Copy input to output unchanged: zcat == cat with --force.
 104  * IN assertion: insize bytes have already been read in inbuf and inptr bytes
 105  * already processed or copied.
 106  */
 107 int copy(in, out)
 108     int in, out;   /* input and output file descriptors */
 109 {
 110     int got;
 111
 112     errno = 0;
 113     while (insize > inptr) {
 114         write_buf(out, (char*)inbuf + inptr, insize - inptr);
 115         got = read_buffer (in, (char *) inbuf, INBUFSIZ);
 116         if (got == -1)
 117             read_error();
 118         bytes_in += got;
 119         insize = (unsigned)got;
 120         inptr = 0;
 121     }
 122     return OK;
 123 }
 124
 125 /* ===========================================================================
 126  * Run a set of bytes through the crc shift register.  If s is a NULL
 127  * pointer, then initialize the crc shift register contents instead.
 128  * Return the current crc in either case.
 129  */
 130 ulg updcrc(s, n)
 131     const uch *s;           /* pointer to bytes to pump through */
 132     unsigned n;             /* number of bytes in s[] */
 133 {
 134     register ulg c;         /* temporary variable */
 135
 136     if (s == NULL) {
 137         c = 0xffffffffL;
 138     } else {
 139         c = crc;
 140         if (n) do {
 141             c = crc_32_tab[((int)c ^ (*s++)) & 0xff] ^ (c >> 8);
 142         } while (--n);
 143     }
 144     crc = c;
 145     return c ^ 0xffffffffL;       /* (instead of ~c for 64-bit machines) */
 146 }
 147
 148 /* Return a current CRC value.  */
 149 ulg
 150 getcrc (void)
 151 {
 152   return crc ^ 0xffffffffL;
 153 }
 154
 155 #ifdef IBM_Z_DFLTCC
 156 /* Set a new CRC value.  */
 157 void
 158 setcrc (ulg c)
 159 {
 160   crc = c ^ 0xffffffffL;
 161 }
 162 #endif
 163
 164 /* ===========================================================================
 165  * Clear input and output buffers
 166  */
 167 void clear_bufs()
 168 {
 169     outcnt = 0;
 170     insize = inptr = 0;
 171     bytes_in = bytes_out = 0L;
 172 }
 173
 174 /* ===========================================================================
 175  * Fill the input buffer. This is called only when the buffer is empty.
 176  */
 177 int fill_inbuf(eof_ok)
 178     int eof_ok;          /* set if EOF acceptable as a result */
 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 (fd, buf, cnt)
 209      int fd;
 210      voidp buf;
 211      unsigned int cnt;
 212 {
 213   int len;
 214   if (INT_MAX < cnt)
 215     cnt = INT_MAX;
 216   len = read (fd, buf, cnt);
 217
 218 #if defined F_SETFL && O_NONBLOCK && defined EAGAIN
 219   /* Input files are opened O_NONBLOCK for security reasons.  On some
 220      file systems this can cause read to fail with errno == EAGAIN.  */
 221   if (len < 0 && errno == EAGAIN)
 222     {
 223       int flags = fcntl (fd, F_GETFL);
 224       if (0 <= flags)
 225         {
 226           if (! (flags & O_NONBLOCK))
 227             errno = EAGAIN;
 228           else if (fcntl (fd, F_SETFL, flags & ~O_NONBLOCK) != -1)
 229             len = read (fd, buf, cnt);
 230         }
 231     }
 232 #endif
 233
 234   return len;
 235 }
 236
 237 /* Likewise for 'write'.  */
 238 static int
 239 write_buffer (fd, buf, cnt)
 240      int fd;
 241      voidp buf;
 242      unsigned int cnt;
 243 {
 244   if (INT_MAX < cnt)
 245     cnt = INT_MAX;
 246   return write (fd, buf, cnt);
 247 }
 248
 249 /* ===========================================================================
 250  * Write the output buffer outbuf[0..outcnt-1] and update bytes_out.
 251  * (used for the compressed data only)
 252  */
 253 void flush_outbuf()
 254 {
 255     if (outcnt == 0) return;
 256
 257     write_buf (ofd, outbuf, outcnt);
 258     outcnt = 0;
 259 }
 260
 261 /* ===========================================================================
 262  * Write the output window window[0..outcnt-1] and update crc and bytes_out.
 263  * (Used for the decompressed data only.)
 264  */
 265 void flush_window()
 266 {
 267     if (outcnt == 0) return;
 268     updcrc(window, outcnt);
 269
 270     write_buf (ofd, window, outcnt);
 271     outcnt = 0;
 272 }
 273
 274 /* ===========================================================================
 275  * Update the count of output bytes.  If testing, do not do any
 276  * output.  Otherwise, write the buffer, checking for errors.
 277  */
 278 void write_buf(fd, buf, cnt)
 279     int       fd;
 280     voidp     buf;
 281     unsigned  cnt;
 282 {
 283     unsigned  n;
 284
 285     bytes_out += cnt;
 286     if (test)
 287       return;
 288
 289     while ((n = write_buffer (fd, buf, cnt)) != cnt) {
 290         if (n == (unsigned)(-1)) {
 291             write_error();
 292         }
 293         cnt -= n;
 294         buf = (voidp)((char*)buf+n);
 295     }
 296 }
 297
 298 /* ========================================================================
 299  * Put string s in lower case, return s.
 300  */
 301 char *strlwr(s)
 302     char *s;
 303 {
 304     char *t;
 305     for (t = s; *t; t++)
 306       *t = tolow ((unsigned char) *t);
 307     return s;
 308 }
 309
 310 /* ========================================================================
 311  * Return the base name of a file (remove any directory prefix and
 312  * any version suffix). For systems with file names that are not
 313  * case sensitive, force the base name to lower case.
 314  */
 315 char *
 316 gzip_base_name (fname)
 317     char *fname;
 318 {
 319     fname = last_component (fname);
 320     if (casemap('A') == 'a') strlwr(fname);
 321     return fname;
 322 }
 323
 324 /* ========================================================================
 325  * Unlink a file, working around the unlink readonly bug (if present).
 326  */
 327 int xunlink (filename)
 328      char *filename;
 329 {
 330   int r = unlink (filename);
 331
 332 #ifdef UNLINK_READONLY_BUG
 333   if (r != 0)
 334     {
 335       int e = errno;
 336       if (chmod (filename, S_IWUSR) != 0)
 337         {
 338           errno = e;
 339           return -1;
 340         }
 341
 342       r = unlink (filename);
 343     }
 344 #endif
 345
 346   return r;
 347 }
 348
 349 #ifdef NO_MULTIPLE_DOTS
 350 /* ========================================================================
 351  * Make a file name legal for file systems not allowing file names with
 352  * multiple dots or starting with a dot (such as MSDOS), by changing
 353  * all dots except the last one into underlines.  A target dependent
 354  * function can be used instead of this simple function by defining the macro
 355  * MAKE_LEGAL_NAME in tailor.h and providing the function in a target
 356  * dependent module.
 357  */
 358 void make_simple_name(name)
 359     char *name;
 360 {
 361     char *p = strrchr(name, '.');
 362     if (p == NULL) return;
 363     if (p == name) p++;
 364     do {
 365         if (*--p == '.') *p = '_';
 366     } while (p != name);
 367 }
 368 #endif
 369
 370 /* Convert the value of the environment variable ENVVAR_NAME
 371    to a newly allocated argument vector, and set *ARGCP and *ARGVP
 372    to the number of arguments and to the vector, respectively.
 373    Make the new vector's zeroth element equal to the old **ARGVP.
 374    Return a pointer to the newly allocated string storage.
 375
 376    If the vector would be empty, do not allocate storage,
 377    do not set *ARGCP and *ARGVP, and return NULL.  */
 378
 379 #define SEPARATOR       " \t"   /* separators in env variable */
 380
 381 char *add_envopt(
 382     int *argcp,          /* pointer to argc */
 383     char ***argvp,       /* pointer to argv */
 384     char const *envvar_name) /* name of environment variable */
 385 {
 386     char *p;             /* running pointer through env variable */
 387     char **oargv;        /* runs through old argv array */
 388     char **nargv;        /* runs through new argv array */
 389     int  nargc = 0;      /* number of arguments in env variable */
 390     char *env_val;
 391
 392     env_val = getenv(envvar_name);
 393     if (env_val == NULL) return NULL;
 394
 395     env_val = xstrdup (env_val);
 396
 397     for (p = env_val; *p; nargc++ ) {        /* move through env_val */
 398         p += strspn(p, SEPARATOR);           /* skip leading separators */
 399         if (*p == '\0') break;
 400
 401         p += strcspn(p, SEPARATOR);          /* find end of word */
 402         if (*p) *p++ = '\0';                 /* mark it */
 403     }
 404     if (nargc == 0) {
 405         free(env_val);
 406         return NULL;
 407     }
 408     *argcp = nargc + 1;
 409     /* Allocate the new argv array, with an extra element just in case
 410      * the original arg list did not end with a NULL.
 411      */
 412     nargv = xcalloc (*argcp + 1, sizeof (char *));
 413     oargv  = *argvp;
 414     *argvp = nargv;
 415
 416     /* Copy the program name first */
 417     *nargv++ = *oargv;
 418
 419     /* Then copy the environment args */
 420     for (p = env_val; nargc > 0; nargc--) {
 421         p += strspn(p, SEPARATOR);           /* skip separators */
 422         *(nargv++) = p;                      /* store start */
 423         while (*p++) ;                       /* skip over word */
 424     }
 425
 426     *nargv = NULL;
 427     return env_val;
 428 }
 429
 430 /* ========================================================================
 431  * Error handlers.
 432  */
 433 void
 434 gzip_error (char const *m)
 435 {
 436     fprintf (stderr, "\n%s: %s: %s\n", program_name, ifname, m);
 437     abort_gzip();
 438 }
 439
 440 void
 441 xalloc_die ()
 442 {
 443   fprintf (stderr, "\n%s: memory_exhausted\n", program_name);
 444   abort_gzip ();
 445 }
 446
 447 void warning (char const *m)
 448 {
 449     WARN ((stderr, "%s: %s: warning: %s\n", program_name, ifname, m));
 450 }
 451
 452 void read_error()
 453 {
 454     int e = errno;
 455     fprintf (stderr, "\n%s: ", program_name);
 456     if (e != 0) {
 457         errno = e;
 458         perror(ifname);
 459     } else {
 460         fprintf(stderr, "%s: unexpected end of file\n", ifname);
 461     }
 462     abort_gzip();
 463 }
 464
 465 void write_error()
 466 {
 467     int e = errno;
 468     fprintf (stderr, "\n%s: ", program_name);
 469     errno = e;
 470     perror(ofname);
 471     abort_gzip();
 472 }
 473
 474 /* ========================================================================
 475  * Display compression ratio on the given stream on 6 characters.
 476  */
 477 void display_ratio(num, den, file)
 478     off_t num;
 479     off_t den;
 480     FILE *file;
 481 {
 482     fprintf(file, "%5.1f%%", den == 0 ? 0 : 100.0 * num / den);
 483 }
 484
 485 /* ========================================================================
 486  * Print an off_t.  There's no completely portable way to use printf,
 487  * so we do it ourselves.
 488  */
 489 void fprint_off(file, offset, width)
 490     FILE *file;
 491     off_t offset;
 492     int width;
 493 {
 494     char buf[CHAR_BIT * sizeof (off_t)];
 495     char *p = buf + sizeof buf;
 496
 497     /* Don't negate offset here; it might overflow.  */
 498     if (offset < 0) {
 499         do
 500           *--p = '0' - offset % 10;
 501         while ((offset /= 10) != 0);
 502
 503         *--p = '-';
 504     } else {
 505         do
 506           *--p = '0' + offset % 10;
 507         while ((offset /= 10) != 0);
 508     }
 509
 510     width -= buf + sizeof buf - p;
 511     while (0 < width--) {
 512         putc (' ', file);
 513     }
 514     for (;  p < buf + sizeof buf;  p++)
 515         putc (*p, file);
 516 }