maint: remove unreachable code
[gzip.git] / util.c
blobbb5e9f3a49cefaa3004e4e72c6d4a618b2173f87
1 /* util.c -- utility functions for gzip support
3 Copyright (C) 1997-1999, 2001-2002, 2006, 2009-2018 Free Software
4 Foundation, Inc.
5 Copyright (C) 1992-1993 Jean-loup Gailly
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.
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.
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. */
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>
30 #include "tailor.h"
31 #include "gzip.h"
32 #include <dirname.h>
33 #include <xalloc.h>
35 #ifndef CHAR_BIT
36 # define CHAR_BIT 8
37 #endif
39 static int write_buffer (int, voidp, unsigned int);
41 /* ========================================================================
42 * Table of CRC-32's of all single-byte values (made by makecrc.c)
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
99 /* ===========================================================================
100 * Copy input to output unchanged: zcat == cat with --force.
101 * IN assertion: insize bytes have already been read in inbuf and inptr bytes
102 * already processed or copied.
104 int copy(in, out)
105 int in, out; /* input and output file descriptors */
107 int got;
109 errno = 0;
110 while (insize > inptr) {
111 write_buf(out, (char*)inbuf + inptr, insize - inptr);
112 bytes_out += insize - inptr;
113 got = read_buffer (in, (char *) inbuf, INBUFSIZ);
114 if (got == -1)
115 read_error();
116 bytes_in += got;
117 insize = (unsigned)got;
118 inptr = 0;
120 return OK;
123 /* ===========================================================================
124 * Run a set of bytes through the crc shift register. If s is a NULL
125 * pointer, then initialize the crc shift register contents instead.
126 * Return the current crc in either case.
128 ulg updcrc(s, n)
129 uch *s; /* pointer to bytes to pump through */
130 unsigned n; /* number of bytes in s[] */
132 register ulg c; /* temporary variable */
134 static ulg crc = (ulg)0xffffffffL; /* shift register contents */
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);
144 crc = c;
145 return c ^ 0xffffffffL; /* (instead of ~c for 64-bit machines) */
148 /* ===========================================================================
149 * Clear input and output buffers
151 void clear_bufs()
153 outcnt = 0;
154 insize = inptr = 0;
155 bytes_in = bytes_out = 0L;
158 /* ===========================================================================
159 * Fill the input buffer. This is called only when the buffer is empty.
161 int fill_inbuf(eof_ok)
162 int eof_ok; /* set if EOF acceptable as a result */
164 int len;
166 /* Read as much as possible */
167 insize = 0;
168 do {
169 len = read_buffer (ifd, (char *) inbuf + insize, INBUFSIZ - insize);
170 if (len == 0) break;
171 if (len == -1) {
172 read_error();
173 break;
175 insize += len;
176 } while (insize < INBUFSIZ);
178 if (insize == 0) {
179 if (eof_ok) return EOF;
180 flush_window();
181 errno = 0;
182 read_error();
184 bytes_in += (off_t)insize;
185 inptr = 1;
186 return inbuf[0];
189 /* Like the standard read function, except do not attempt to read more
190 than INT_MAX bytes at a time. */
192 read_buffer (fd, buf, cnt)
193 int fd;
194 voidp buf;
195 unsigned int cnt;
197 int len;
198 if (INT_MAX < cnt)
199 cnt = INT_MAX;
200 len = read (fd, buf, cnt);
202 #if defined F_SETFL && O_NONBLOCK && defined EAGAIN
203 /* Input files are opened O_NONBLOCK for security reasons. On some
204 file systems this can cause read to fail with errno == EAGAIN. */
205 if (len < 0 && errno == EAGAIN)
207 int flags = fcntl (fd, F_GETFL);
208 if (0 <= flags)
210 if (! (flags & O_NONBLOCK))
211 errno = EAGAIN;
212 else if (fcntl (fd, F_SETFL, flags & ~O_NONBLOCK) != -1)
213 len = read (fd, buf, cnt);
216 #endif
218 return len;
221 /* Likewise for 'write'. */
222 static int
223 write_buffer (fd, buf, cnt)
224 int fd;
225 voidp buf;
226 unsigned int cnt;
228 if (INT_MAX < cnt)
229 cnt = INT_MAX;
230 return write (fd, buf, cnt);
233 /* ===========================================================================
234 * Write the output buffer outbuf[0..outcnt-1] and update bytes_out.
235 * (used for the compressed data only)
237 void flush_outbuf()
239 if (outcnt == 0) return;
241 write_buf(ofd, (char *)outbuf, outcnt);
242 bytes_out += (off_t)outcnt;
243 outcnt = 0;
246 /* ===========================================================================
247 * Write the output window window[0..outcnt-1] and update crc and bytes_out.
248 * (Used for the decompressed data only.)
250 void flush_window()
252 if (outcnt == 0) return;
253 updcrc(window, outcnt);
255 if (!test) {
256 write_buf(ofd, (char *)window, outcnt);
258 bytes_out += (off_t)outcnt;
259 outcnt = 0;
262 /* ===========================================================================
263 * Does the same as write(), but also handles partial pipe writes and checks
264 * for error return.
266 void write_buf(fd, buf, cnt)
267 int fd;
268 voidp buf;
269 unsigned cnt;
271 unsigned n;
273 while ((n = write_buffer (fd, buf, cnt)) != cnt) {
274 if (n == (unsigned)(-1)) {
275 write_error();
277 cnt -= n;
278 buf = (voidp)((char*)buf+n);
282 /* ========================================================================
283 * Put string s in lower case, return s.
285 char *strlwr(s)
286 char *s;
288 char *t;
289 for (t = s; *t; t++)
290 *t = tolow ((unsigned char) *t);
291 return s;
294 /* ========================================================================
295 * Return the base name of a file (remove any directory prefix and
296 * any version suffix). For systems with file names that are not
297 * case sensitive, force the base name to lower case.
299 char *
300 gzip_base_name (fname)
301 char *fname;
303 fname = last_component (fname);
304 if (casemap('A') == 'a') strlwr(fname);
305 return fname;
308 /* ========================================================================
309 * Unlink a file, working around the unlink readonly bug (if present).
311 int xunlink (filename)
312 char *filename;
314 int r = unlink (filename);
316 #ifdef UNLINK_READONLY_BUG
317 if (r != 0)
319 int e = errno;
320 if (chmod (filename, S_IWUSR) != 0)
322 errno = e;
323 return -1;
326 r = unlink (filename);
328 #endif
330 return r;
333 /* ========================================================================
334 * Make a file name legal for file systems not allowing file names with
335 * multiple dots or starting with a dot (such as MSDOS), by changing
336 * all dots except the last one into underlines. A target dependent
337 * function can be used instead of this simple function by defining the macro
338 * MAKE_LEGAL_NAME in tailor.h and providing the function in a target
339 * dependent module.
341 void make_simple_name(name)
342 char *name;
344 char *p = strrchr(name, '.');
345 if (p == NULL) return;
346 if (p == name) p++;
347 do {
348 if (*--p == '.') *p = '_';
349 } while (p != name);
352 /* Convert the value of the environment variable ENVVAR_NAME
353 to a newly allocated argument vector, and set *ARGCP and *ARGVP
354 to the number of arguments and to the vector, respectively.
355 Make the new vector's zeroth element equal to the old **ARGVP.
356 Return a pointer to the newly allocated string storage.
358 If the vector would be empty, do not allocate storage,
359 do not set *ARGCP and *ARGVP, and return NULL. */
361 #define SEPARATOR " \t" /* separators in env variable */
363 char *add_envopt(
364 int *argcp, /* pointer to argc */
365 char ***argvp, /* pointer to argv */
366 char const *envvar_name) /* name of environment variable */
368 char *p; /* running pointer through env variable */
369 char **oargv; /* runs through old argv array */
370 char **nargv; /* runs through new argv array */
371 int nargc = 0; /* number of arguments in env variable */
372 char *env_val;
374 env_val = getenv(envvar_name);
375 if (env_val == NULL) return NULL;
377 env_val = xstrdup (env_val);
379 for (p = env_val; *p; nargc++ ) { /* move through env_val */
380 p += strspn(p, SEPARATOR); /* skip leading separators */
381 if (*p == '\0') break;
383 p += strcspn(p, SEPARATOR); /* find end of word */
384 if (*p) *p++ = '\0'; /* mark it */
386 if (nargc == 0) {
387 free(env_val);
388 return NULL;
390 *argcp = nargc + 1;
391 /* Allocate the new argv array, with an extra element just in case
392 * the original arg list did not end with a NULL.
394 nargv = xcalloc (*argcp + 1, sizeof (char *));
395 oargv = *argvp;
396 *argvp = nargv;
398 /* Copy the program name first */
399 *nargv++ = *oargv;
401 /* Then copy the environment args */
402 for (p = env_val; nargc > 0; nargc--) {
403 p += strspn(p, SEPARATOR); /* skip separators */
404 *(nargv++) = p; /* store start */
405 while (*p++) ; /* skip over word */
408 *nargv = NULL;
409 return env_val;
412 /* ========================================================================
413 * Error handlers.
415 void
416 gzip_error (char const *m)
418 fprintf (stderr, "\n%s: %s: %s\n", program_name, ifname, m);
419 abort_gzip();
422 void
423 xalloc_die ()
425 fprintf (stderr, "\n%s: memory_exhausted\n", program_name);
426 abort_gzip ();
429 void warning (char const *m)
431 WARN ((stderr, "%s: %s: warning: %s\n", program_name, ifname, m));
434 void read_error()
436 int e = errno;
437 fprintf (stderr, "\n%s: ", program_name);
438 if (e != 0) {
439 errno = e;
440 perror(ifname);
441 } else {
442 fprintf(stderr, "%s: unexpected end of file\n", ifname);
444 abort_gzip();
447 void write_error()
449 int e = errno;
450 fprintf (stderr, "\n%s: ", program_name);
451 errno = e;
452 perror(ofname);
453 abort_gzip();
456 /* ========================================================================
457 * Display compression ratio on the given stream on 6 characters.
459 void display_ratio(num, den, file)
460 off_t num;
461 off_t den;
462 FILE *file;
464 fprintf(file, "%5.1f%%", den == 0 ? 0 : 100.0 * num / den);
467 /* ========================================================================
468 * Print an off_t. There's no completely portable way to use printf,
469 * so we do it ourselves.
471 void fprint_off(file, offset, width)
472 FILE *file;
473 off_t offset;
474 int width;
476 char buf[CHAR_BIT * sizeof (off_t)];
477 char *p = buf + sizeof buf;
479 /* Don't negate offset here; it might overflow. */
480 if (offset < 0) {
482 *--p = '0' - offset % 10;
483 while ((offset /= 10) != 0);
485 *--p = '-';
486 } else {
488 *--p = '0' + offset % 10;
489 while ((offset /= 10) != 0);
492 width -= buf + sizeof buf - p;
493 while (0 < width--) {
494 putc (' ', file);
496 for (; p < buf + sizeof buf; p++)
497 putc (*p, file);