/* * 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" #include #ifdef HAVE_UNISTD_H #include #endif #include #ifdef HAVE_SYS_WAIT_H #include #endif #ifdef HAVE_LIBZ #include #endif #ifndef lint FILE_RCSID("@(#)$Id: compress.c,v 1.25 2002/07/03 18:26:37 christos Exp $") #endif static struct { const char *magic; int maglen; const char *const 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 */ { "BZh", 3, { "bzip2", "-cd", NULL }, 1 }, /* bzip2-ed */ }; static int ncompr = sizeof(compr) / sizeof(compr[0]); static int swrite(int, const void *, size_t); static int sread(int, void *, size_t); static int uncompressbuf(int, const unsigned char *, unsigned char **, int); #ifdef HAVE_LIBZ static int uncompressgzipped(const unsigned char *, unsigned char **, int); #endif int zmagic(const char *fname, unsigned char *buf, int nbytes) { unsigned char *newbuf; int newsize; int i; for (i = 0; i < ncompr; i++) { if (nbytes < compr[i].maglen) continue; if (memcmp(buf, compr[i].magic, compr[i].maglen) == 0 && (newsize = uncompressbuf(i, buf, &newbuf, nbytes)) != 0) { tryit(fname, newbuf, newsize, 1); free(newbuf); printf(" ("); tryit(fname, buf, nbytes, 0); printf(")"); return 1; } } if (i == ncompr) return 0; return 1; } /* * `safe' write for sockets and pipes. */ static int swrite(int fd, const void *buf, size_t n) { int rv; size_t rn = n; do switch (rv = write(fd, buf, n)) { case -1: if (errno == EINTR) continue; return -1; default: n -= rv; buf = ((const char *)buf) + rv; break; } while (n > 0); return rn; } /* * `safe' read for sockets and pipes. */ static int sread(int fd, void *buf, size_t n) { int rv; size_t rn = n; 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; } int pipe2file(int fd, void *startbuf, size_t nbytes) { char buf[4096]; int r, tfd; (void)strcpy(buf, "/tmp/file.XXXXXX"); #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 tfd = mkstemp(buf); r = errno; (void)unlink(buf); errno = r; #endif if (tfd == -1) { error("Can't create temporary file for pipe copy (%s)\n", strerror(errno)); /*NOTREACHED*/ } if (swrite(tfd, startbuf, nbytes) != nbytes) r = 1; else { while ((r = sread(fd, buf, sizeof(buf))) > 0) if (swrite(tfd, buf, r) != r) break; } switch (r) { case -1: error("Error copying from pipe to temp file (%s)\n", strerror(errno)); /*NOTREACHED*/ case 0: break; default: error("Error while writing to temp file (%s)\n", strerror(errno)); /*NOTREACHED*/ } /* * 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) { error("Couldn't dup destcriptor for temp file(%s)\n", strerror(errno)); /*NOTREACHED*/ } (void)close(tfd); if (lseek(fd, (off_t)0, SEEK_SET) == (off_t)-1) { error("Couldn't seek on temp file (%s)\n", strerror(errno)); /*NOTREACHED*/ } return fd; } #ifdef HAVE_LIBZ #define FHCRC (1 << 1) #define FEXTRA (1 << 2) #define FNAME (1 << 3) #define FCOMMENT (1 << 4) static int uncompressgzipped(const unsigned char *old, unsigned char **newch, int n) { unsigned char flg = old[3]; int data_start = 10; z_stream z; int rc; if (flg & FEXTRA) data_start += 2 + old[data_start] + old[data_start + 1] * 256; if (flg & FNAME) { while(old[data_start]) data_start++; data_start++; } if(flg & FCOMMENT) { while(old[data_start]) data_start++; data_start++; } if(flg & FHCRC) data_start += 2; if ((*newch = (unsigned char *)malloc(HOWMANY + 1)) == NULL) { return 0; } z.next_in = (Bytef *)(old + data_start); z.avail_in = n - data_start; z.next_out = *newch; z.avail_out = HOWMANY; z.zalloc = Z_NULL; z.zfree = Z_NULL; z.opaque = Z_NULL; rc = inflateInit2(&z, -15); if (rc != Z_OK) { (void) fprintf(stderr,"%s: zlib: %s\n", progname, z.msg); return 0; } rc = inflate(&z, Z_SYNC_FLUSH); if (rc != Z_OK && rc != Z_STREAM_END) { fprintf(stderr,"%s: zlib: %s\n", progname, z.msg); return 0; } n = z.total_out; inflateEnd(&z); /* let's keep the nul-terminate tradition */ (*newch)[n++] = '\0'; return n; } #endif static int uncompressbuf(int method, const unsigned char *old, unsigned char **newch, int n) { int fdin[2], fdout[2]; /* The buffer is NUL terminated, and we don't need that. */ n--; #ifdef HAVE_LIBZ if (method == 2) return uncompressgzipped(old,newch,n); #endif if (pipe(fdin) == -1 || pipe(fdout) == -1) { error("cannot create pipe (%s).\n", strerror(errno)); /*NOTREACHED*/ } switch (fork()) { case 0: /* child */ (void) close(0); (void) dup(fdin[0]); (void) close(fdin[0]); (void) close(fdin[1]); (void) close(1); (void) dup(fdout[1]); (void) close(fdout[0]); (void) close(fdout[1]); if (compr[method].silent) (void) close(2); execvp(compr[method].argv[0], (char *const *)compr[method].argv); exit(1); /*NOTREACHED*/ case -1: error("could not fork (%s).\n", strerror(errno)); /*NOTREACHED*/ default: /* parent */ (void) close(fdin[0]); (void) close(fdout[1]); if (swrite(fdin[1], old, n) != n) { n = 0; goto err; } (void) close(fdin[1]); fdin[1] = -1; if ((*newch = (unsigned char *) malloc(HOWMANY + 1)) == NULL) { n = 0; goto err; } if ((n = sread(fdout[0], *newch, HOWMANY)) <= 0) { free(*newch); n = 0; goto err; } /* NUL terminate, as every buffer is handled here. */ (*newch)[n++] = '\0'; err: if (fdin[1] != -1) (void) close(fdin[1]); (void) close(fdout[0]); (void) wait(NULL); return n; } }