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mirror of https://git.FreeBSD.org/src.git synced 2024-12-15 10:17:20 +00:00
freebsd/usr.bin/compress/compress.c
Tom Rhodes 33ffdd8115 Don't truncate the output file before making sure that we can
read at least 1 byte from the input file without problems.  This
fixes a bug in uncompress(1) that causes the accidental removal
of files that happen to have the same name as the output file,
even when the uncompression fails and is aborted, i.e.:

$ echo hello world > hello
$ touch hello.Z
$ ls -l hello*
-rw-rw-r--  1 giorgos  giorgos  12 Jun 14 13:33 hello
-rw-rw-r--  1 giorgos  giorgos   0 Jun 14 13:33 hello.Z
$ ./uncompress -f hello
uncompress: hello.Z: Inappropriate file type or format
$ ls -l hello*
-rw-rw-r--  1 giorgos  giorgos  0 Jun 14 13:33 hello.Z
$

PR:		46787
Submitted by:	keramida
2003-06-14 13:41:31 +00:00

441 lines
9.6 KiB
C

/*-
* Copyright (c) 1992, 1993
* The Regents of the University of California. All rights reserved.
*
* 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, 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
*/
#ifndef lint
static const char copyright[] =
"@(#) Copyright (c) 1992, 1993\n\
The Regents of the University of California. All rights reserved.\n";
#endif
#if 0
#ifndef lint
static char sccsid[] = "@(#)compress.c 8.2 (Berkeley) 1/7/94";
#endif
#endif
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <err.h>
#include <errno.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "zopen.h"
void compress(const char *, const char *, int);
void cwarn(const char *, ...) __printflike(1, 2);
void cwarnx(const char *, ...) __printflike(1, 2);
void decompress(const char *, const char *, int);
int permission(const char *);
void setfile(const char *, struct stat *);
void usage(int);
int eval, force, verbose;
int
main(int argc, char *argv[])
{
enum {COMPRESS, DECOMPRESS} style;
size_t len;
int bits, cat, ch;
char *p, newname[MAXPATHLEN];
cat = 0;
if ((p = rindex(argv[0], '/')) == NULL)
p = argv[0];
else
++p;
if (!strcmp(p, "uncompress"))
style = DECOMPRESS;
else if (!strcmp(p, "compress"))
style = COMPRESS;
else if (!strcmp(p, "zcat")) {
cat = 1;
style = DECOMPRESS;
} else
errx(1, "unknown program name");
bits = 0;
while ((ch = getopt(argc, argv, "b:cdfv")) != -1)
switch(ch) {
case 'b':
bits = strtol(optarg, &p, 10);
if (*p)
errx(1, "illegal bit count -- %s", optarg);
break;
case 'c':
cat = 1;
break;
case 'd': /* Backward compatible. */
style = DECOMPRESS;
break;
case 'f':
force = 1;
break;
case 'v':
verbose = 1;
break;
case '?':
default:
usage(style == COMPRESS);
}
argc -= optind;
argv += optind;
if (argc == 0) {
switch(style) {
case COMPRESS:
(void)compress("/dev/stdin", "/dev/stdout", bits);
break;
case DECOMPRESS:
(void)decompress("/dev/stdin", "/dev/stdout", bits);
break;
}
exit (eval);
}
if (cat == 1 && argc > 1)
errx(1, "the -c option permits only a single file argument");
for (; *argv; ++argv)
switch(style) {
case COMPRESS:
if (strcmp(*argv, "-") == 0) {
compress("/dev/stdin", "/dev/stdout", bits);
break;
} else if (cat) {
compress(*argv, "/dev/stdout", bits);
break;
}
if ((p = rindex(*argv, '.')) != NULL &&
!strcmp(p, ".Z")) {
cwarnx("%s: name already has trailing .Z",
*argv);
break;
}
len = strlen(*argv);
if (len > sizeof(newname) - 3) {
cwarnx("%s: name too long", *argv);
break;
}
memmove(newname, *argv, len);
newname[len] = '.';
newname[len + 1] = 'Z';
newname[len + 2] = '\0';
compress(*argv, newname, bits);
break;
case DECOMPRESS:
if (strcmp(*argv, "-") == 0) {
decompress("/dev/stdin", "/dev/stdout", bits);
break;
}
len = strlen(*argv);
if ((p = rindex(*argv, '.')) == NULL ||
strcmp(p, ".Z")) {
if (len > sizeof(newname) - 3) {
cwarnx("%s: name too long", *argv);
break;
}
memmove(newname, *argv, len);
newname[len] = '.';
newname[len + 1] = 'Z';
newname[len + 2] = '\0';
decompress(newname,
cat ? "/dev/stdout" : *argv, bits);
} else {
if (len - 2 > sizeof(newname) - 1) {
cwarnx("%s: name too long", *argv);
break;
}
memmove(newname, *argv, len - 2);
newname[len - 2] = '\0';
decompress(*argv,
cat ? "/dev/stdout" : newname, bits);
}
break;
}
exit (eval);
}
void
compress(const char *in, const char *out, int bits)
{
size_t nr;
struct stat isb, sb;
FILE *ifp, *ofp;
int exists, isreg, oreg;
u_char buf[1024];
exists = !stat(out, &sb);
if (!force && exists && S_ISREG(sb.st_mode) && !permission(out))
return;
isreg = oreg = !exists || S_ISREG(sb.st_mode);
ifp = ofp = NULL;
if ((ifp = fopen(in, "r")) == NULL) {
cwarn("%s", in);
return;
}
if (stat(in, &isb)) { /* DON'T FSTAT! */
cwarn("%s", in);
goto err;
}
if (!S_ISREG(isb.st_mode))
isreg = 0;
if ((ofp = zopen(out, "w", bits)) == NULL) {
cwarn("%s", out);
goto err;
}
while ((nr = fread(buf, 1, sizeof(buf), ifp)) != 0)
if (fwrite(buf, 1, nr, ofp) != nr) {
cwarn("%s", out);
goto err;
}
if (ferror(ifp) || fclose(ifp)) {
cwarn("%s", in);
goto err;
}
ifp = NULL;
if (fclose(ofp)) {
cwarn("%s", out);
goto err;
}
ofp = NULL;
if (isreg) {
if (stat(out, &sb)) {
cwarn("%s", out);
goto err;
}
if (!force && sb.st_size >= isb.st_size) {
if (verbose)
(void)fprintf(stderr, "%s: file would grow; left unmodified\n",
in);
eval = 2;
if (unlink(out))
cwarn("%s", out);
goto err;
}
setfile(out, &isb);
if (unlink(in))
cwarn("%s", in);
if (verbose) {
(void)fprintf(stderr, "%s: ", out);
if (isb.st_size > sb.st_size)
(void)fprintf(stderr, "%.0f%% compression\n",
((float)sb.st_size / isb.st_size) * 100.0);
else
(void)fprintf(stderr, "%.0f%% expansion\n",
((float)isb.st_size / sb.st_size) * 100.0);
}
}
return;
err: if (ofp) {
if (oreg)
(void)unlink(out);
(void)fclose(ofp);
}
if (ifp)
(void)fclose(ifp);
}
void
decompress(const char *in, const char *out, int bits)
{
size_t nr;
struct stat sb;
FILE *ifp, *ofp;
int exists, isreg, oreg;
u_char buf[1024];
exists = !stat(out, &sb);
if (!force && exists && S_ISREG(sb.st_mode) && !permission(out))
return;
isreg = oreg = !exists || S_ISREG(sb.st_mode);
ifp = ofp = NULL;
if ((ifp = zopen(in, "r", bits)) == NULL) {
cwarn("%s", in);
return;
}
if (stat(in, &sb)) {
cwarn("%s", in);
goto err;
}
if (!S_ISREG(sb.st_mode))
isreg = 0;
/*
* Try to read the first few uncompressed bytes from the input file
* before blindly truncating the output file.
*/
if ((nr = fread(buf, 1, sizeof(buf), ifp)) == 0) {
cwarn("%s", in);
(void)fclose(ifp);
return;
}
if ((ofp = fopen(out, "w")) == NULL ||
(nr != 0 && fwrite(buf, 1, nr, ofp) != nr)) {
cwarn("%s", out);
(void)fclose(ifp);
return;
}
while ((nr = fread(buf, 1, sizeof(buf), ifp)) != 0)
if (fwrite(buf, 1, nr, ofp) != nr) {
cwarn("%s", out);
goto err;
}
if (ferror(ifp) || fclose(ifp)) {
cwarn("%s", in);
goto err;
}
ifp = NULL;
if (fclose(ofp)) {
cwarn("%s", out);
goto err;
}
if (isreg) {
setfile(out, &sb);
if (unlink(in))
cwarn("%s", in);
}
return;
err: if (ofp) {
if (oreg)
(void)unlink(out);
(void)fclose(ofp);
}
if (ifp)
(void)fclose(ifp);
}
void
setfile(const char *name, struct stat *fs)
{
static struct timeval tv[2];
fs->st_mode &= S_ISUID|S_ISGID|S_IRWXU|S_IRWXG|S_IRWXO;
TIMESPEC_TO_TIMEVAL(&tv[0], &fs->st_atimespec);
TIMESPEC_TO_TIMEVAL(&tv[1], &fs->st_mtimespec);
if (utimes(name, tv))
cwarn("utimes: %s", name);
/*
* Changing the ownership probably won't succeed, unless we're root
* or POSIX_CHOWN_RESTRICTED is not set. Set uid/gid before setting
* the mode; current BSD behavior is to remove all setuid bits on
* chown. If chown fails, lose setuid/setgid bits.
*/
if (chown(name, fs->st_uid, fs->st_gid)) {
if (errno != EPERM)
cwarn("chown: %s", name);
fs->st_mode &= ~(S_ISUID|S_ISGID);
}
if (chmod(name, fs->st_mode) && errno != EOPNOTSUPP)
cwarn("chmod: %s", name);
if (chflags(name, fs->st_flags) && errno != EOPNOTSUPP)
cwarn("chflags: %s", name);
}
int
permission(const char *fname)
{
int ch, first;
if (!isatty(fileno(stderr)))
return (0);
(void)fprintf(stderr, "overwrite %s? ", fname);
first = ch = getchar();
while (ch != '\n' && ch != EOF)
ch = getchar();
return (first == 'y');
}
void
usage(int iscompress)
{
if (iscompress)
(void)fprintf(stderr,
"usage: compress [-cfv] [-b bits] [file ...]\n");
else
(void)fprintf(stderr,
"usage: uncompress [-c] [-b bits] [file ...]\n");
exit(1);
}
void
cwarnx(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
vwarnx(fmt, ap);
va_end(ap);
eval = 1;
}
void
cwarn(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
vwarn(fmt, ap);
va_end(ap);
eval = 1;
}