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Diffstat (limited to 'src/compress.c')
| -rw-r--r-- | src/compress.c | 506 |
1 files changed, 506 insertions, 0 deletions
diff --git a/src/compress.c b/src/compress.c new file mode 100644 index 0000000..084970b --- /dev/null +++ b/src/compress.c @@ -0,0 +1,506 @@ +/* + * Copyright (c) Ian F. Darwin 1986-1995. + * Software written by Ian F. Darwin and others; + * maintained 1995-present by Christos Zoulas and others. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice immediately at the beginning of the file, without modification, + * this list of conditions, and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR + * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ +/* + * compress routines: + * zmagic() - returns 0 if not recognized, uncompresses and prints + * information if recognized + * uncompress(method, old, n, newch) - uncompress old into new, + * using method, return sizeof new + */ +#include "file.h" + +#ifndef lint +FILE_RCSID("@(#)$File: compress.c,v 1.70 2012/11/07 17:54:48 christos Exp $") +#endif + +#include "magic.h" +#include <stdlib.h> +#ifdef HAVE_UNISTD_H +#include <unistd.h> +#endif +#include <string.h> +#include <errno.h> +#ifndef __MINGW32__ +#include <sys/ioctl.h> +#endif +#ifdef HAVE_SYS_WAIT_H +#include <sys/wait.h> +#endif +#if defined(HAVE_SYS_TIME_H) +#include <sys/time.h> +#endif +#if defined(HAVE_ZLIB_H) && defined(HAVE_LIBZ) +#define BUILTIN_DECOMPRESS +#include <zlib.h> +#endif + +private const struct { + const char magic[8]; + size_t maglen; + const char *argv[3]; + int silent; +} compr[] = { + { "\037\235", 2, { "gzip", "-cdq", NULL }, 1 }, /* compressed */ + /* Uncompress can get stuck; so use gzip first if we have it + * Idea from Damien Clark, thanks! */ + { "\037\235", 2, { "uncompress", "-c", NULL }, 1 }, /* compressed */ + { "\037\213", 2, { "gzip", "-cdq", NULL }, 1 }, /* gzipped */ + { "\037\236", 2, { "gzip", "-cdq", NULL }, 1 }, /* frozen */ + { "\037\240", 2, { "gzip", "-cdq", NULL }, 1 }, /* SCO LZH */ + /* the standard pack utilities do not accept standard input */ + { "\037\036", 2, { "gzip", "-cdq", NULL }, 0 }, /* packed */ + { "PK\3\4", 4, { "gzip", "-cdq", NULL }, 1 }, /* pkzipped, */ + /* ...only first file examined */ + { "BZh", 3, { "bzip2", "-cd", NULL }, 1 }, /* bzip2-ed */ + { "LZIP", 4, { "lzip", "-cdq", NULL }, 1 }, + { "\3757zXZ\0",6,{ "xz", "-cd", NULL }, 1 }, /* XZ Utils */ + { "LRZI", 4, { "lrzip", "-dqo-", NULL }, 1 }, /* LRZIP */ +}; + +#define NODATA ((size_t)~0) + +private ssize_t swrite(int, const void *, size_t); +#if HAVE_FORK +private size_t ncompr = sizeof(compr) / sizeof(compr[0]); +private size_t uncompressbuf(struct magic_set *, int, size_t, + const unsigned char *, unsigned char **, size_t); +#ifdef BUILTIN_DECOMPRESS +private size_t uncompressgzipped(struct magic_set *, const unsigned char *, + unsigned char **, size_t); +#endif + +protected int +file_zmagic(struct magic_set *ms, int fd, const char *name, + const unsigned char *buf, size_t nbytes) +{ + unsigned char *newbuf = NULL; + size_t i, nsz; + int rv = 0; + int mime = ms->flags & MAGIC_MIME; + + if ((ms->flags & MAGIC_COMPRESS) == 0) + return 0; + + for (i = 0; i < ncompr; i++) { + if (nbytes < compr[i].maglen) + continue; + if (memcmp(buf, compr[i].magic, compr[i].maglen) == 0 && + (nsz = uncompressbuf(ms, fd, i, buf, &newbuf, + nbytes)) != NODATA) { + ms->flags &= ~MAGIC_COMPRESS; + rv = -1; + if (file_buffer(ms, -1, name, newbuf, nsz) == -1) + goto error; + + if (mime == MAGIC_MIME || mime == 0) { + if (file_printf(ms, mime ? + " compressed-encoding=" : " (") == -1) + goto error; + } + + if ((mime == 0 || mime & MAGIC_MIME_ENCODING) && + file_buffer(ms, -1, NULL, buf, nbytes) == -1) + goto error; + + if (!mime && file_printf(ms, ")") == -1) + goto error; + rv = 1; + break; + } + } +error: + free(newbuf); + ms->flags |= MAGIC_COMPRESS; + return rv; +} +#endif +/* + * `safe' write for sockets and pipes. + */ +private ssize_t +swrite(int fd, const void *buf, size_t n) +{ + ssize_t rv; + size_t rn = n; + + do + switch (rv = write(fd, buf, n)) { + case -1: + if (errno == EINTR) + continue; + return -1; + default: + n -= rv; + buf = CAST(const char *, buf) + rv; + break; + } + while (n > 0); + return rn; +} + + +/* + * `safe' read for sockets and pipes. + */ +protected ssize_t +sread(int fd, void *buf, size_t n, int canbepipe __attribute__((__unused__))) +{ + ssize_t rv; +#ifdef FIONREAD + int t = 0; +#endif + size_t rn = n; + + if (fd == STDIN_FILENO) + goto nocheck; + +#ifdef FIONREAD + if (canbepipe && (ioctl(fd, FIONREAD, &t) == -1 || t == 0)) { +#ifdef FD_ZERO + ssize_t cnt; + for (cnt = 0;; cnt++) { + fd_set check; + struct timeval tout = {0, 100 * 1000}; + int selrv; + + FD_ZERO(&check); + FD_SET(fd, &check); + + /* + * Avoid soft deadlock: do not read if there + * is nothing to read from sockets and pipes. + */ + selrv = select(fd + 1, &check, NULL, NULL, &tout); + if (selrv == -1) { + if (errno == EINTR || errno == EAGAIN) + continue; + } else if (selrv == 0 && cnt >= 5) { + return 0; + } else + break; + } +#endif + (void)ioctl(fd, FIONREAD, &t); + } + + if (t > 0 && (size_t)t < n) { + n = t; + rn = n; + } +#endif + +nocheck: + do + switch ((rv = read(fd, buf, n))) { + case -1: + if (errno == EINTR) + continue; + return -1; + case 0: + return rn - n; + default: + n -= rv; + buf = ((char *)buf) + rv; + break; + } + while (n > 0); + return rn; +} + +protected int +file_pipe2file(struct magic_set *ms, int fd, const void *startbuf, + size_t nbytes) +{ + char buf[4096]; + ssize_t r; + int tfd; + + (void)strlcpy(buf, "/tmp/file.XXXXXX", sizeof buf); +#ifndef HAVE_MKSTEMP + { + char *ptr = mktemp(buf); + tfd = open(ptr, O_RDWR|O_TRUNC|O_EXCL|O_CREAT, 0600); + r = errno; + (void)unlink(ptr); + errno = r; + } +#else + { + int te; + tfd = mkstemp(buf); + te = errno; + (void)unlink(buf); + errno = te; + } +#endif + if (tfd == -1) { + file_error(ms, errno, + "cannot create temporary file for pipe copy"); + return -1; + } + + if (swrite(tfd, startbuf, nbytes) != (ssize_t)nbytes) + r = 1; + else { + while ((r = sread(fd, buf, sizeof(buf), 1)) > 0) + if (swrite(tfd, buf, (size_t)r) != r) + break; + } + + switch (r) { + case -1: + file_error(ms, errno, "error copying from pipe to temp file"); + return -1; + case 0: + break; + default: + file_error(ms, errno, "error while writing to temp file"); + return -1; + } + + /* + * We duplicate the file descriptor, because fclose on a + * tmpfile will delete the file, but any open descriptors + * can still access the phantom inode. + */ + if ((fd = dup2(tfd, fd)) == -1) { + file_error(ms, errno, "could not dup descriptor for temp file"); + return -1; + } + (void)close(tfd); + if (lseek(fd, (off_t)0, SEEK_SET) == (off_t)-1) { + file_badseek(ms); + return -1; + } + return fd; +} +#if HAVE_FORK +#ifdef BUILTIN_DECOMPRESS + +#define FHCRC (1 << 1) +#define FEXTRA (1 << 2) +#define FNAME (1 << 3) +#define FCOMMENT (1 << 4) + +private size_t +uncompressgzipped(struct magic_set *ms, const unsigned char *old, + unsigned char **newch, size_t n) +{ + unsigned char flg = old[3]; + size_t data_start = 10; + z_stream z; + int rc; + + if (flg & FEXTRA) { + if (data_start+1 >= n) + return 0; + data_start += 2 + old[data_start] + old[data_start + 1] * 256; + } + if (flg & FNAME) { + while(data_start < n && old[data_start]) + data_start++; + data_start++; + } + if(flg & FCOMMENT) { + while(data_start < n && old[data_start]) + data_start++; + data_start++; + } + if(flg & FHCRC) + data_start += 2; + + if (data_start >= n) + return 0; + if ((*newch = CAST(unsigned char *, malloc(HOWMANY + 1))) == NULL) { + return 0; + } + + /* XXX: const castaway, via strchr */ + z.next_in = (Bytef *)strchr((const char *)old + data_start, + old[data_start]); + z.avail_in = CAST(uint32_t, (n - data_start)); + z.next_out = *newch; + z.avail_out = HOWMANY; + z.zalloc = Z_NULL; + z.zfree = Z_NULL; + z.opaque = Z_NULL; + + /* LINTED bug in header macro */ + rc = inflateInit2(&z, -15); + if (rc != Z_OK) { + file_error(ms, 0, "zlib: %s", z.msg); + return 0; + } + + rc = inflate(&z, Z_SYNC_FLUSH); + if (rc != Z_OK && rc != Z_STREAM_END) { + file_error(ms, 0, "zlib: %s", z.msg); + return 0; + } + + n = (size_t)z.total_out; + (void)inflateEnd(&z); + + /* let's keep the nul-terminate tradition */ + (*newch)[n] = '\0'; + + return n; +} +#endif + +private size_t +uncompressbuf(struct magic_set *ms, int fd, size_t method, + const unsigned char *old, unsigned char **newch, size_t n) +{ + int fdin[2], fdout[2]; + ssize_t r; + pid_t pid; + +#ifdef BUILTIN_DECOMPRESS + /* FIXME: This doesn't cope with bzip2 */ + if (method == 2) + return uncompressgzipped(ms, old, newch, n); +#endif + (void)fflush(stdout); + (void)fflush(stderr); + + if ((fd != -1 && pipe(fdin) == -1) || pipe(fdout) == -1) { + file_error(ms, errno, "cannot create pipe"); + return NODATA; + } + switch (pid = fork()) { + case 0: /* child */ + (void) close(0); + if (fd != -1) { + if (dup(fd) == -1) + _exit(1); + (void) lseek(0, (off_t)0, SEEK_SET); + } else { + if (dup(fdin[0]) == -1) + _exit(1); + (void) close(fdin[0]); + (void) close(fdin[1]); + } + + (void) close(1); + if (dup(fdout[1]) == -1) + _exit(1); + (void) close(fdout[0]); + (void) close(fdout[1]); +#ifndef DEBUG + if (compr[method].silent) + (void)close(2); +#endif + + (void)execvp(compr[method].argv[0], + (char *const *)(intptr_t)compr[method].argv); +#ifdef DEBUG + (void)fprintf(stderr, "exec `%s' failed (%s)\n", + compr[method].argv[0], strerror(errno)); +#endif + exit(1); + /*NOTREACHED*/ + case -1: + file_error(ms, errno, "could not fork"); + return NODATA; + + default: /* parent */ + (void) close(fdout[1]); + if (fd == -1) { + (void) close(fdin[0]); + /* + * fork again, to avoid blocking because both + * pipes filled + */ + switch (fork()) { + case 0: /* child */ + (void)close(fdout[0]); + if (swrite(fdin[1], old, n) != (ssize_t)n) { +#ifdef DEBUG + (void)fprintf(stderr, + "Write failed (%s)\n", + strerror(errno)); +#endif + exit(1); + } + exit(0); + /*NOTREACHED*/ + + case -1: +#ifdef DEBUG + (void)fprintf(stderr, "Fork failed (%s)\n", + strerror(errno)); +#endif + exit(1); + /*NOTREACHED*/ + + default: /* parent */ + break; + } + (void) close(fdin[1]); + fdin[1] = -1; + } + + if ((*newch = (unsigned char *) malloc(HOWMANY + 1)) == NULL) { +#ifdef DEBUG + (void)fprintf(stderr, "Malloc failed (%s)\n", + strerror(errno)); +#endif + n = 0; + goto err; + } + if ((r = sread(fdout[0], *newch, HOWMANY, 0)) <= 0) { +#ifdef DEBUG + (void)fprintf(stderr, "Read failed (%s)\n", + strerror(errno)); +#endif + free(*newch); + n = 0; + newch[0] = '\0'; + goto err; + } else { + n = r; + } + /* NUL terminate, as every buffer is handled here. */ + (*newch)[n] = '\0'; +err: + if (fdin[1] != -1) + (void) close(fdin[1]); + (void) close(fdout[0]); +#ifdef WNOHANG + while (waitpid(pid, NULL, WNOHANG) != -1) + continue; +#else + (void)wait(NULL); +#endif + (void) close(fdin[0]); + + return n; + } +} +#endif |