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/*
* Copyright (C) 2016 Jo-Philipp Wich <jo@mein.io>
* Copyright (C) 2016 Felix Fietkau <nbd@nbd.name>
*
* Zlib decrompression utility routines.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Library General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <poll.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include "gzip.h"
static void to_devnull(int fd)
{
int devnull = open("/dev/null", fd ? O_WRONLY : O_RDONLY);
if (devnull >= 0)
dup2(devnull, fd);
if (devnull > STDERR_FILENO)
close(devnull);
}
static void *gzip_thread(void *ptr)
{
struct gzip_handle *zh = ptr;
char buf[4096];
int len = 0, ret;
while (1) {
if (zh->file)
len = fread(buf, 1, sizeof(buf), zh->file);
else if (zh->gzip)
len = gzip_read(zh->gzip, buf, sizeof(buf));
if (len <= 0)
break;
do {
ret = write(zh->wfd, buf, len);
} while (ret == -1 && errno == EINTR);
}
close(zh->wfd);
zh->wfd = -1;
return NULL;
}
int gzip_exec(struct gzip_handle *zh, const char *filename)
{
int rpipe[2] = { -1, -1 }, wpipe[2] = {
-1, -1};
struct sigaction pipe_sa = {.sa_handler = SIG_IGN };
zh->rfd = -1;
zh->wfd = -1;
if (sigaction(SIGPIPE, &pipe_sa, &zh->pipe_sa) < 0)
return -1;
if (pipe(rpipe) < 0)
return -1;
if (!filename && pipe(wpipe) < 0) {
close(rpipe[0]);
close(rpipe[1]);
return -1;
}
zh->pid = vfork();
switch (zh->pid) {
case -1:
return -1;
case 0:
to_devnull(STDERR_FILENO);
if (filename) {
to_devnull(STDIN_FILENO);
} else {
dup2(wpipe[0], STDIN_FILENO);
close(wpipe[0]);
close(wpipe[1]);
}
dup2(rpipe[1], STDOUT_FILENO);
close(rpipe[0]);
close(rpipe[1]);
execlp("gzip", "gzip", "-d", "-c", filename, NULL);
exit(-1);
default:
zh->rfd = rpipe[0];
zh->wfd = wpipe[1];
fcntl(zh->rfd, F_SETFD, fcntl(zh->rfd, F_GETFD) | FD_CLOEXEC);
close(rpipe[1]);
if (zh->wfd >= 0) {
fcntl(zh->wfd, F_SETFD,
fcntl(zh->wfd, F_GETFD) | FD_CLOEXEC);
close(wpipe[0]);
pthread_create(&zh->thread, NULL, gzip_thread, zh);
}
}
return 0;
}
ssize_t gzip_read(struct gzip_handle * zh, void *buf, ssize_t len)
{
ssize_t ret;
do {
ret = read(zh->rfd, buf, len);
} while (ret == -1 && errno != EINTR);
return ret;
}
ssize_t gzip_copy(struct gzip_handle * zh, FILE * out, ssize_t len)
{
char buf[4096];
ssize_t rlen, total = 0;
while (len > 0) {
rlen = gzip_read(zh, buf,
(len > sizeof(buf)) ? sizeof(buf) : len);
if (rlen <= 0)
break;
if (out != NULL) {
if (fwrite(buf, 1, rlen, out) != rlen)
break;
}
len -= rlen;
total += rlen;
}
return total;
}
FILE *gzip_fdopen(struct gzip_handle * zh, const char *filename)
{
memset(zh, 0, sizeof(*zh));
if (!filename || gzip_exec(zh, filename) < 0)
return NULL;
fcntl(zh->rfd, F_SETFL, fcntl(zh->rfd, F_GETFL) & ~O_NONBLOCK);
return fdopen(zh->rfd, "r");
}
int gzip_close(struct gzip_handle *zh)
{
int code = -1;
if (zh->rfd >= 0)
close(zh->rfd);
if (zh->wfd >= 0)
close(zh->wfd);
if (zh->pid > 0) {
kill(zh->pid, SIGKILL);
waitpid(zh->pid, &code, 0);
}
if (zh->file)
fclose(zh->file);
if (zh->thread)
pthread_join(zh->thread, NULL);
sigaction(SIGPIPE, &zh->pipe_sa, NULL);
return WIFEXITED(code) ? WEXITSTATUS(code) : -1;
}
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