Annotation of src/usr.bin/file/compress.c, Revision 1.13
1.13 ! chl 1: /* $OpenBSD: compress.c,v 1.12 2008/05/08 01:40:56 chl Exp $ */
1.1 deraadt 2: /*
1.7 ian 3: * Copyright (c) Ian F. Darwin 1986-1995.
4: * Software written by Ian F. Darwin and others;
5: * maintained 1995-present by Christos Zoulas and others.
6: *
7: * Redistribution and use in source and binary forms, with or without
8: * modification, are permitted provided that the following conditions
9: * are met:
10: * 1. Redistributions of source code must retain the above copyright
11: * notice immediately at the beginning of the file, without modification,
12: * this list of conditions, and the following disclaimer.
13: * 2. Redistributions in binary form must reproduce the above copyright
14: * notice, this list of conditions and the following disclaimer in the
15: * documentation and/or other materials provided with the distribution.
16: *
17: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20: * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
21: * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27: * SUCH DAMAGE.
1.1 deraadt 28: */
1.11 tedu 29: /*
30: * compress routines:
31: * zmagic() - returns 0 if not recognized, uncompresses and prints
32: * information if recognized
33: * uncompress(method, old, n, newch) - uncompress old into new,
34: * using method, return sizeof new
35: */
1.6 ian 36: #include "file.h"
1.11 tedu 37: #include "magic.h"
38: #include <stdio.h>
1.6 ian 39: #include <stdlib.h>
1.11 tedu 40: #ifdef HAVE_UNISTD_H
1.6 ian 41: #include <unistd.h>
42: #endif
43: #include <string.h>
1.11 tedu 44: #include <errno.h>
45: #include <sys/types.h>
1.12 chl 46: #include <sys/ioctl.h>
1.11 tedu 47: #ifdef HAVE_SYS_WAIT_H
1.4 mickey 48: #include <sys/wait.h>
1.6 ian 49: #endif
1.12 chl 50: #if defined(HAVE_SYS_TIME_H)
51: #include <sys/time.h>
52: #endif
1.13 ! chl 53: #if defined(HAVE_ZLIB_H) && defined(HAVE_LIBZ)
! 54: #define BUILTIN_DECOMPRESS
1.6 ian 55: #include <zlib.h>
56: #endif
1.1 deraadt 57:
1.12 chl 58:
1.11 tedu 59: #ifndef lint
1.13 ! chl 60: FILE_RCSID("@(#)$Id: compress.c,v 1.12 2008/05/08 01:40:56 chl Exp $")
1.11 tedu 61: #endif
62:
1.13 ! chl 63: private const struct {
! 64: const char magic[8];
1.11 tedu 65: size_t maglen;
1.13 ! chl 66: const char *argv[3];
1.11 tedu 67: int silent;
1.1 deraadt 68: } compr[] = {
1.11 tedu 69: { "\037\235", 2, { "gzip", "-cdq", NULL }, 1 }, /* compressed */
70: /* Uncompress can get stuck; so use gzip first if we have it
71: * Idea from Damien Clark, thanks! */
72: { "\037\235", 2, { "uncompress", "-c", NULL }, 1 }, /* compressed */
73: { "\037\213", 2, { "gzip", "-cdq", NULL }, 1 }, /* gzipped */
74: { "\037\236", 2, { "gzip", "-cdq", NULL }, 1 }, /* frozen */
75: { "\037\240", 2, { "gzip", "-cdq", NULL }, 1 }, /* SCO LZH */
76: /* the standard pack utilities do not accept standard input */
77: { "\037\036", 2, { "gzip", "-cdq", NULL }, 0 }, /* packed */
1.12 chl 78: { "PK\3\4", 4, { "gzip", "-cdq", NULL }, 1 }, /* pkzipped, */
79: /* ...only first file examined */
1.11 tedu 80: { "BZh", 3, { "bzip2", "-cd", NULL }, 1 }, /* bzip2-ed */
1.1 deraadt 81: };
82:
1.12 chl 83: private size_t ncompr = sizeof(compr) / sizeof(compr[0]);
84:
85: #define NODATA ((size_t)~0)
1.1 deraadt 86:
87:
1.11 tedu 88: private ssize_t swrite(int, const void *, size_t);
1.12 chl 89: private size_t uncompressbuf(struct magic_set *, int, size_t,
90: const unsigned char *, unsigned char **, size_t);
1.13 ! chl 91: #ifdef BUILTIN_DECOMPRESS
1.11 tedu 92: private size_t uncompressgzipped(struct magic_set *, const unsigned char *,
93: unsigned char **, size_t);
94: #endif
1.1 deraadt 95:
1.11 tedu 96: protected int
1.12 chl 97: file_zmagic(struct magic_set *ms, int fd, const char *name,
98: const unsigned char *buf, size_t nbytes)
1.1 deraadt 99: {
1.11 tedu 100: unsigned char *newbuf = NULL;
101: size_t i, nsz;
102: int rv = 0;
1.13 ! chl 103: int mime = ms->flags & MAGIC_MIME;
1.11 tedu 104:
105: if ((ms->flags & MAGIC_COMPRESS) == 0)
106: return 0;
1.1 deraadt 107:
108: for (i = 0; i < ncompr; i++) {
109: if (nbytes < compr[i].maglen)
110: continue;
1.11 tedu 111: if (memcmp(buf, compr[i].magic, compr[i].maglen) == 0 &&
1.12 chl 112: (nsz = uncompressbuf(ms, fd, i, buf, &newbuf,
113: nbytes)) != NODATA) {
1.11 tedu 114: ms->flags &= ~MAGIC_COMPRESS;
115: rv = -1;
1.12 chl 116: if (file_buffer(ms, -1, name, newbuf, nsz) == -1)
1.11 tedu 117: goto error;
1.13 ! chl 118:
! 119: if (mime == MAGIC_MIME || mime == 0) {
! 120: if (file_printf(ms, mime ?
! 121: " compressed-encoding=" : " (") == -1)
! 122: goto error;
! 123: }
! 124:
! 125: if ((mime == 0 || mime & MAGIC_MIME_ENCODING) &&
! 126: file_buffer(ms, -1, NULL, buf, nbytes) == -1)
1.11 tedu 127: goto error;
1.13 ! chl 128:
! 129: if (!mime && file_printf(ms, ")") == -1)
1.11 tedu 130: goto error;
131: rv = 1;
1.1 deraadt 132: break;
1.11 tedu 133: }
1.1 deraadt 134: }
1.11 tedu 135: error:
136: if (newbuf)
1.1 deraadt 137: free(newbuf);
1.11 tedu 138: ms->flags |= MAGIC_COMPRESS;
139: return rv;
1.1 deraadt 140: }
141:
1.6 ian 142: /*
143: * `safe' write for sockets and pipes.
144: */
1.11 tedu 145: private ssize_t
1.6 ian 146: swrite(int fd, const void *buf, size_t n)
147: {
148: int rv;
149: size_t rn = n;
150:
151: do
152: switch (rv = write(fd, buf, n)) {
153: case -1:
154: if (errno == EINTR)
155: continue;
156: return -1;
157: default:
158: n -= rv;
159: buf = ((const char *)buf) + rv;
160: break;
161: }
162: while (n > 0);
163: return rn;
164: }
165:
1.11 tedu 166:
1.6 ian 167: /*
168: * `safe' read for sockets and pipes.
169: */
1.12 chl 170: protected ssize_t
171: sread(int fd, void *buf, size_t n, int canbepipe)
1.6 ian 172: {
1.12 chl 173: int rv, cnt;
174: #ifdef FIONREAD
175: int t = 0;
176: #endif
1.6 ian 177: size_t rn = n;
178:
1.12 chl 179: if (fd == STDIN_FILENO)
180: goto nocheck;
181:
182: #ifdef FIONREAD
183: if ((canbepipe && (ioctl(fd, FIONREAD, &t) == -1)) || (t == 0)) {
184: #ifdef FD_ZERO
185: for (cnt = 0;; cnt++) {
186: fd_set check;
187: struct timeval tout = {0, 100 * 1000};
188: int selrv;
189:
190: FD_ZERO(&check);
191: FD_SET(fd, &check);
192:
193: /*
194: * Avoid soft deadlock: do not read if there
195: * is nothing to read from sockets and pipes.
196: */
197: selrv = select(fd + 1, &check, NULL, NULL, &tout);
198: if (selrv == -1) {
199: if (errno == EINTR || errno == EAGAIN)
200: continue;
201: } else if (selrv == 0 && cnt >= 5) {
202: return 0;
203: } else
204: break;
205: }
206: #endif
207: (void)ioctl(fd, FIONREAD, &t);
208: }
209:
210: if (t > 0 && (size_t)t < n) {
211: n = t;
212: rn = n;
213: }
214: #endif
215:
216: nocheck:
1.6 ian 217: do
1.12 chl 218: switch ((rv = read(fd, buf, n))) {
1.6 ian 219: case -1:
220: if (errno == EINTR)
221: continue;
222: return -1;
223: case 0:
224: return rn - n;
225: default:
226: n -= rv;
227: buf = ((char *)buf) + rv;
228: break;
229: }
230: while (n > 0);
231: return rn;
232: }
233:
1.11 tedu 234: protected int
235: file_pipe2file(struct magic_set *ms, int fd, const void *startbuf,
236: size_t nbytes)
1.6 ian 237: {
238: char buf[4096];
239: int r, tfd;
240:
1.11 tedu 241: (void)strlcpy(buf, "/tmp/file.XXXXXX", sizeof buf);
1.6 ian 242: #ifndef HAVE_MKSTEMP
243: {
244: char *ptr = mktemp(buf);
245: tfd = open(ptr, O_RDWR|O_TRUNC|O_EXCL|O_CREAT, 0600);
246: r = errno;
247: (void)unlink(ptr);
248: errno = r;
249: }
250: #else
251: tfd = mkstemp(buf);
252: r = errno;
253: (void)unlink(buf);
254: errno = r;
255: #endif
256: if (tfd == -1) {
1.11 tedu 257: file_error(ms, errno,
258: "cannot create temporary file for pipe copy");
259: return -1;
1.6 ian 260: }
261:
1.11 tedu 262: if (swrite(tfd, startbuf, nbytes) != (ssize_t)nbytes)
1.6 ian 263: r = 1;
264: else {
1.12 chl 265: while ((r = sread(fd, buf, sizeof(buf), 1)) > 0)
1.11 tedu 266: if (swrite(tfd, buf, (size_t)r) != r)
1.6 ian 267: break;
268: }
269:
270: switch (r) {
271: case -1:
1.11 tedu 272: file_error(ms, errno, "error copying from pipe to temp file");
273: return -1;
1.6 ian 274: case 0:
275: break;
276: default:
1.11 tedu 277: file_error(ms, errno, "error while writing to temp file");
278: return -1;
1.6 ian 279: }
280:
281: /*
282: * We duplicate the file descriptor, because fclose on a
283: * tmpfile will delete the file, but any open descriptors
284: * can still access the phantom inode.
285: */
286: if ((fd = dup2(tfd, fd)) == -1) {
1.11 tedu 287: file_error(ms, errno, "could not dup descriptor for temp file");
288: return -1;
1.6 ian 289: }
290: (void)close(tfd);
291: if (lseek(fd, (off_t)0, SEEK_SET) == (off_t)-1) {
1.11 tedu 292: file_badseek(ms);
293: return -1;
1.6 ian 294: }
295: return fd;
296: }
1.1 deraadt 297:
1.13 ! chl 298: #ifdef BUILTIN_DECOMPRESS
1.11 tedu 299:
300: #define FHCRC (1 << 1)
301: #define FEXTRA (1 << 2)
302: #define FNAME (1 << 3)
303: #define FCOMMENT (1 << 4)
304:
305: private size_t
306: uncompressgzipped(struct magic_set *ms, const unsigned char *old,
307: unsigned char **newch, size_t n)
308: {
309: unsigned char flg = old[3];
310: size_t data_start = 10;
311: z_stream z;
312: int rc;
313:
314: if (flg & FEXTRA) {
315: if (data_start+1 >= n)
316: return 0;
317: data_start += 2 + old[data_start] + old[data_start + 1] * 256;
318: }
319: if (flg & FNAME) {
320: while(data_start < n && old[data_start])
321: data_start++;
322: data_start++;
323: }
324: if(flg & FCOMMENT) {
325: while(data_start < n && old[data_start])
326: data_start++;
327: data_start++;
328: }
329: if(flg & FHCRC)
330: data_start += 2;
331:
332: if (data_start >= n)
333: return 0;
334: if ((*newch = (unsigned char *)malloc(HOWMANY + 1)) == NULL) {
335: return 0;
336: }
337:
338: /* XXX: const castaway, via strchr */
339: z.next_in = (Bytef *)strchr((const char *)old + data_start,
340: old[data_start]);
341: z.avail_in = n - data_start;
342: z.next_out = *newch;
343: z.avail_out = HOWMANY;
344: z.zalloc = Z_NULL;
345: z.zfree = Z_NULL;
346: z.opaque = Z_NULL;
347:
348: rc = inflateInit2(&z, -15);
349: if (rc != Z_OK) {
350: file_error(ms, 0, "zlib: %s", z.msg);
351: return 0;
352: }
353:
354: rc = inflate(&z, Z_SYNC_FLUSH);
355: if (rc != Z_OK && rc != Z_STREAM_END) {
356: file_error(ms, 0, "zlib: %s", z.msg);
357: return 0;
358: }
359:
360: n = (size_t)z.total_out;
1.12 chl 361: (void)inflateEnd(&z);
1.11 tedu 362:
363: /* let's keep the nul-terminate tradition */
1.12 chl 364: (*newch)[n] = '\0';
1.11 tedu 365:
366: return n;
367: }
368: #endif
369:
370: private size_t
1.12 chl 371: uncompressbuf(struct magic_set *ms, int fd, size_t method,
372: const unsigned char *old, unsigned char **newch, size_t n)
1.1 deraadt 373: {
374: int fdin[2], fdout[2];
1.11 tedu 375: int r;
376:
1.13 ! chl 377: #ifdef BUILTIN_DECOMPRESS
! 378: /* FIXME: This doesn't cope with bzip2 */
1.11 tedu 379: if (method == 2)
380: return uncompressgzipped(ms, old, newch, n);
381: #endif
1.12 chl 382: (void)fflush(stdout);
383: (void)fflush(stderr);
1.1 deraadt 384:
1.12 chl 385: if ((fd != -1 && pipe(fdin) == -1) || pipe(fdout) == -1) {
1.11 tedu 386: file_error(ms, errno, "cannot create pipe");
1.12 chl 387: return NODATA;
1.1 deraadt 388: }
389: switch (fork()) {
390: case 0: /* child */
391: (void) close(0);
1.12 chl 392: if (fd != -1) {
393: (void) dup(fd);
394: (void) lseek(0, (off_t)0, SEEK_SET);
395: } else {
396: (void) dup(fdin[0]);
397: (void) close(fdin[0]);
398: (void) close(fdin[1]);
399: }
1.1 deraadt 400:
401: (void) close(1);
402: (void) dup(fdout[1]);
403: (void) close(fdout[0]);
404: (void) close(fdout[1]);
1.12 chl 405: #ifndef DEBUG
1.1 deraadt 406: if (compr[method].silent)
1.12 chl 407: (void)close(2);
408: #endif
1.1 deraadt 409:
1.12 chl 410: (void)execvp(compr[method].argv[0],
411: (char *const *)(intptr_t)compr[method].argv);
412: #ifdef DEBUG
413: (void)fprintf(stderr, "exec `%s' failed (%s)\n",
414: compr[method].argv[0], strerror(errno));
415: #endif
1.11 tedu 416: exit(1);
1.1 deraadt 417: /*NOTREACHED*/
418: case -1:
1.11 tedu 419: file_error(ms, errno, "could not fork");
1.12 chl 420: return NODATA;
1.1 deraadt 421:
422: default: /* parent */
423: (void) close(fdout[1]);
1.12 chl 424: if (fd == -1) {
425: (void) close(fdin[0]);
426: /*
427: * fork again, to avoid blocking because both
428: * pipes filled
429: */
430: switch (fork()) {
431: case 0: /* child */
432: (void)close(fdout[0]);
433: if (swrite(fdin[1], old, n) != (ssize_t)n) {
434: #ifdef DEBUG
435: (void)fprintf(stderr,
436: "Write failed (%s)\n",
437: strerror(errno));
438: #endif
439: exit(1);
440: }
441: exit(0);
442: /*NOTREACHED*/
443:
444: case -1:
445: #ifdef DEBUG
446: (void)fprintf(stderr, "Fork failed (%s)\n",
447: strerror(errno));
448: #endif
1.11 tedu 449: exit(1);
1.12 chl 450: /*NOTREACHED*/
1.11 tedu 451:
1.12 chl 452: default: /* parent */
453: break;
454: }
455: (void) close(fdin[1]);
456: fdin[1] = -1;
457: }
1.11 tedu 458:
459: if ((*newch = (unsigned char *) malloc(HOWMANY + 1)) == NULL) {
1.12 chl 460: #ifdef DEBUG
461: (void)fprintf(stderr, "Malloc failed (%s)\n",
462: strerror(errno));
463: #endif
1.11 tedu 464: n = 0;
465: goto err;
1.1 deraadt 466: }
1.12 chl 467: if ((r = sread(fdout[0], *newch, HOWMANY, 0)) <= 0) {
468: #ifdef DEBUG
469: (void)fprintf(stderr, "Read failed (%s)\n",
470: strerror(errno));
471: #endif
1.1 deraadt 472: free(*newch);
1.11 tedu 473: n = 0;
474: newch[0] = '\0';
475: goto err;
476: } else {
477: n = r;
1.1 deraadt 478: }
1.11 tedu 479: /* NUL terminate, as every buffer is handled here. */
1.12 chl 480: (*newch)[n] = '\0';
1.11 tedu 481: err:
482: if (fdin[1] != -1)
483: (void) close(fdin[1]);
1.1 deraadt 484: (void) close(fdout[0]);
1.11 tedu 485: #ifdef WNOHANG
486: while (waitpid(-1, NULL, WNOHANG) != -1)
487: continue;
488: #else
489: (void)wait(NULL);
490: #endif
1.1 deraadt 491: return n;
492: }
493: }
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