399 lines
9.0 KiB
C
399 lines
9.0 KiB
C
/*
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* Copyright (c) Ian F. Darwin 1986-1995.
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* Software written by Ian F. Darwin and others;
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* maintained 1995-present by Christos Zoulas and others.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice immediately at the beginning of the file, without modification,
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* this list of conditions, and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
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* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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/*
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* compress routines:
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* zmagic() - returns 0 if not recognized, uncompresses and prints
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* information if recognized
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* uncompress(method, old, n, newch) - uncompress old into new,
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* using method, return sizeof new
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*/
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#include "file.h"
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#include "magic.h"
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#include <stdio.h>
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#include <stdlib.h>
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#ifdef HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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#include <string.h>
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#include <errno.h>
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#include <sys/types.h>
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#ifdef HAVE_SYS_WAIT_H
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#include <sys/wait.h>
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#endif
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#ifdef HAVE_LIBZ
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#include <zlib.h>
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#endif
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#ifndef lint
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FILE_RCSID("@(#)$Id: compress.c,v 1.38 2004/09/11 19:15:57 christos Exp $")
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#endif
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private struct {
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const char *magic;
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size_t maglen;
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const char *const argv[3];
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int silent;
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} compr[] = {
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{ "\037\235", 2, { "gzip", "-cdq", NULL }, 1 }, /* compressed */
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/* Uncompress can get stuck; so use gzip first if we have it
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* Idea from Damien Clark, thanks! */
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{ "\037\235", 2, { "uncompress", "-c", NULL }, 1 }, /* compressed */
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{ "\037\213", 2, { "gzip", "-cdq", NULL }, 1 }, /* gzipped */
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{ "\037\236", 2, { "gzip", "-cdq", NULL }, 1 }, /* frozen */
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{ "\037\240", 2, { "gzip", "-cdq", NULL }, 1 }, /* SCO LZH */
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/* the standard pack utilities do not accept standard input */
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{ "\037\036", 2, { "gzip", "-cdq", NULL }, 0 }, /* packed */
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{ "BZh", 3, { "bzip2", "-cd", NULL }, 1 }, /* bzip2-ed */
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};
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private int ncompr = sizeof(compr) / sizeof(compr[0]);
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private ssize_t swrite(int, const void *, size_t);
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private ssize_t sread(int, void *, size_t);
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private size_t uncompressbuf(struct magic_set *, size_t, const unsigned char *,
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unsigned char **, size_t);
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#ifdef HAVE_LIBZ
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private size_t uncompressgzipped(struct magic_set *, const unsigned char *,
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unsigned char **, size_t);
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#endif
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protected int
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file_zmagic(struct magic_set *ms, const unsigned char *buf, size_t nbytes)
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{
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unsigned char *newbuf = NULL;
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size_t i, nsz;
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int rv = 0;
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if ((ms->flags & MAGIC_COMPRESS) == 0)
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return 0;
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for (i = 0; i < ncompr; i++) {
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if (nbytes < compr[i].maglen)
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continue;
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if (memcmp(buf, compr[i].magic, compr[i].maglen) == 0 &&
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(nsz = uncompressbuf(ms, i, buf, &newbuf, nbytes)) != 0) {
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ms->flags &= ~MAGIC_COMPRESS;
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rv = -1;
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if (file_buffer(ms, newbuf, nsz) == -1)
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goto error;
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if (file_printf(ms, " (") == -1)
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goto error;
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if (file_buffer(ms, buf, nbytes) == -1)
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goto error;
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if (file_printf(ms, ")") == -1)
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goto error;
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rv = 1;
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break;
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}
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}
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error:
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if (newbuf)
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free(newbuf);
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ms->flags |= MAGIC_COMPRESS;
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return rv;
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}
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/*
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* `safe' write for sockets and pipes.
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*/
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private ssize_t
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swrite(int fd, const void *buf, size_t n)
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{
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int rv;
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size_t rn = n;
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do
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switch (rv = write(fd, buf, n)) {
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case -1:
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if (errno == EINTR)
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continue;
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return -1;
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default:
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n -= rv;
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buf = ((const char *)buf) + rv;
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break;
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}
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while (n > 0);
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return rn;
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}
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/*
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* `safe' read for sockets and pipes.
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*/
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private ssize_t
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sread(int fd, void *buf, size_t n)
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{
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int rv;
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size_t rn = n;
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do
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switch (rv = read(fd, buf, n)) {
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case -1:
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if (errno == EINTR)
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continue;
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return -1;
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case 0:
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return rn - n;
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default:
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n -= rv;
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buf = ((char *)buf) + rv;
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break;
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}
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while (n > 0);
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return rn;
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}
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protected int
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file_pipe2file(struct magic_set *ms, int fd, const void *startbuf,
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size_t nbytes)
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{
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char buf[4096];
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int r, tfd;
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(void)strcpy(buf, "/tmp/file.XXXXXX");
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#ifndef HAVE_MKSTEMP
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{
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char *ptr = mktemp(buf);
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tfd = open(ptr, O_RDWR|O_TRUNC|O_EXCL|O_CREAT, 0600);
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r = errno;
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(void)unlink(ptr);
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errno = r;
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}
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#else
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tfd = mkstemp(buf);
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r = errno;
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(void)unlink(buf);
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errno = r;
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#endif
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if (tfd == -1) {
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file_error(ms, errno,
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"cannot create temporary file for pipe copy");
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return -1;
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}
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if (swrite(tfd, startbuf, nbytes) != (ssize_t)nbytes)
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r = 1;
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else {
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while ((r = sread(fd, buf, sizeof(buf))) > 0)
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if (swrite(tfd, buf, (size_t)r) != r)
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break;
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}
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switch (r) {
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case -1:
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file_error(ms, errno, "error copying from pipe to temp file");
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return -1;
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case 0:
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break;
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default:
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file_error(ms, errno, "error while writing to temp file");
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return -1;
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}
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/*
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* We duplicate the file descriptor, because fclose on a
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* tmpfile will delete the file, but any open descriptors
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* can still access the phantom inode.
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*/
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if ((fd = dup2(tfd, fd)) == -1) {
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file_error(ms, errno, "could not dup descriptor for temp file");
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return -1;
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}
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(void)close(tfd);
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if (lseek(fd, (off_t)0, SEEK_SET) == (off_t)-1) {
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file_badseek(ms);
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return -1;
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}
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return fd;
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}
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#ifdef HAVE_LIBZ
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#define FHCRC (1 << 1)
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#define FEXTRA (1 << 2)
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#define FNAME (1 << 3)
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#define FCOMMENT (1 << 4)
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private size_t
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uncompressgzipped(struct magic_set *ms, const unsigned char *old,
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unsigned char **newch, size_t n)
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{
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unsigned char flg = old[3];
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size_t data_start = 10;
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z_stream z;
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int rc;
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if (flg & FEXTRA) {
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if (data_start+1 >= n)
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return 0;
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data_start += 2 + old[data_start] + old[data_start + 1] * 256;
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}
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if (flg & FNAME) {
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while(data_start < n && old[data_start])
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data_start++;
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data_start++;
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}
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if(flg & FCOMMENT) {
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while(data_start < n && old[data_start])
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data_start++;
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data_start++;
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}
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if(flg & FHCRC)
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data_start += 2;
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if (data_start >= n)
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return 0;
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if ((*newch = (unsigned char *)malloc(HOWMANY + 1)) == NULL) {
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return 0;
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}
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/* XXX: const castaway, via strchr */
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z.next_in = (Bytef *)strchr((const char *)old + data_start,
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old[data_start]);
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z.avail_in = n - data_start;
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z.next_out = *newch;
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z.avail_out = HOWMANY;
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z.zalloc = Z_NULL;
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z.zfree = Z_NULL;
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z.opaque = Z_NULL;
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rc = inflateInit2(&z, -15);
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if (rc != Z_OK) {
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file_error(ms, 0, "zlib: %s", z.msg);
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return 0;
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}
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rc = inflate(&z, Z_SYNC_FLUSH);
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if (rc != Z_OK && rc != Z_STREAM_END) {
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file_error(ms, 0, "zlib: %s", z.msg);
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return 0;
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}
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n = (size_t)z.total_out;
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inflateEnd(&z);
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/* let's keep the nul-terminate tradition */
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(*newch)[n++] = '\0';
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return n;
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}
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#endif
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private size_t
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uncompressbuf(struct magic_set *ms, size_t method, const unsigned char *old,
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unsigned char **newch, size_t n)
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{
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int fdin[2], fdout[2];
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int r;
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/* The buffer is NUL terminated, and we don't need that. */
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n--;
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#ifdef HAVE_LIBZ
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if (method == 2)
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return uncompressgzipped(ms, old, newch, n);
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#endif
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if (pipe(fdin) == -1 || pipe(fdout) == -1) {
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file_error(ms, errno, "cannot create pipe");
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return 0;
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}
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switch (fork()) {
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case 0: /* child */
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(void) close(0);
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(void) dup(fdin[0]);
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(void) close(fdin[0]);
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(void) close(fdin[1]);
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(void) close(1);
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(void) dup(fdout[1]);
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(void) close(fdout[0]);
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(void) close(fdout[1]);
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if (compr[method].silent)
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(void) close(2);
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execvp(compr[method].argv[0],
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(char *const *)compr[method].argv);
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exit(1);
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/*NOTREACHED*/
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case -1:
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file_error(ms, errno, "could not fork");
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return 0;
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default: /* parent */
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(void) close(fdin[0]);
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(void) close(fdout[1]);
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/* fork again, to avoid blocking because both pipes filled */
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switch (fork()) {
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case 0: /* child */
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(void)close(fdout[0]);
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if (swrite(fdin[1], old, n) != n)
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exit(1);
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exit(0);
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/*NOTREACHED*/
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case -1:
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exit(1);
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/*NOTREACHED*/
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default: /* parent */
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break;
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}
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(void) close(fdin[1]);
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fdin[1] = -1;
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if ((*newch = (unsigned char *) malloc(HOWMANY + 1)) == NULL) {
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n = 0;
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goto err;
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}
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if ((r = sread(fdout[0], *newch, HOWMANY)) <= 0) {
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free(*newch);
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n = 0;
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newch[0] = '\0';
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goto err;
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} else {
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n = r;
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}
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/* NUL terminate, as every buffer is handled here. */
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(*newch)[n++] = '\0';
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err:
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if (fdin[1] != -1)
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(void) close(fdin[1]);
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(void) close(fdout[0]);
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#ifdef WNOHANG
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while (waitpid(-1, NULL, WNOHANG) != -1)
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continue;
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#else
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(void)wait(NULL);
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#endif
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return n;
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}
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}
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