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mirror of https://git.FreeBSD.org/src.git synced 2024-12-21 11:13:30 +00:00
freebsd/contrib/file/compress.c
2002-09-16 05:54:26 +00:00

330 lines
6.6 KiB
C

/*
* 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 <stdlib.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <string.h>
#ifdef HAVE_SYS_WAIT_H
#include <sys/wait.h>
#endif
#ifdef HAVE_LIBZ
#include <zlib.h>
#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;
}
}