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/*
* This file is part of mpv.
*
* mpv is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* mpv 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with mpv. If not, see <http://www.gnu.org/licenses/>.
*/
#include "osdep/posix-spawn.h"
#include <poll.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <fcntl.h>
#include <errno.h>
#include <signal.h>
#include "osdep/subprocess.h"
#include "common/common.h"
#include "misc/thread_tools.h"
#include "osdep/io.h"
#include "stream/stream.h"
extern char **environ;
#define SAFE_CLOSE(fd) do { if ((fd) >= 0) close((fd)); (fd) = -1; } while (0)
void mp_subprocess2(struct mp_subprocess_opts *opts,
struct mp_subprocess_result *res)
{
posix_spawn_file_actions_t fa;
bool fa_destroy = false;
int status = -1;
int comm_pipe[MP_SUBPROCESS_MAX_FDS][2];
int devnull = -1;
pid_t pid = -1;
bool spawned = false;
bool killed_by_us = false;
int cancel_fd = -1;
*res = (struct mp_subprocess_result){0};
for (int n = 0; n < opts->num_fds; n++)
comm_pipe[n][0] = comm_pipe[n][1] = -1;
if (opts->cancel) {
cancel_fd = mp_cancel_get_fd(opts->cancel);
if (cancel_fd < 0)
goto done;
}
for (int n = 0; n < opts->num_fds; n++) {
if (opts->fds[n].on_read && mp_make_cloexec_pipe(comm_pipe[n]) < 0)
goto done;
}
devnull = open("/dev/null", O_RDONLY | O_CLOEXEC);
if (devnull < 0)
goto done;
if (posix_spawn_file_actions_init(&fa))
goto done;
fa_destroy = true;
// redirect FDs
for (int n = 0; n < opts->num_fds; n++) {
int src_fd = devnull;
if (comm_pipe[n][1] >= 0)
src_fd = comm_pipe[n][1];
if (opts->fds[n].src_fd >= 0)
src_fd = opts->fds[n].src_fd;
if (posix_spawn_file_actions_adddup2(&fa, src_fd, opts->fds[n].fd))
goto done;
}
char **env = opts->env ? opts->env : environ;
if (posix_spawnp(&pid, opts->exe, &fa, NULL, opts->args, env)) {
pid = -1;
goto done;
}
spawned = true;
for (int n = 0; n < opts->num_fds; n++)
SAFE_CLOSE(comm_pipe[n][1]);
SAFE_CLOSE(devnull);
while (1) {
struct pollfd fds[MP_SUBPROCESS_MAX_FDS + 1];
int map_fds[MP_SUBPROCESS_MAX_FDS + 1];
int num_fds = 0;
for (int n = 0; n < opts->num_fds; n++) {
if (comm_pipe[n][0] >= 0) {
map_fds[num_fds] = n;
fds[num_fds++] = (struct pollfd){
.events = POLLIN,
.fd = comm_pipe[n][0],
};
}
}
if (!num_fds)
break;
if (cancel_fd >= 0) {
map_fds[num_fds] = -1;
fds[num_fds++] = (struct pollfd){.events = POLLIN, .fd = cancel_fd};
}
if (poll(fds, num_fds, -1) < 0 && errno != EINTR)
break;
for (int idx = 0; idx < num_fds; idx++) {
if (fds[idx].revents) {
int n = map_fds[idx];
if (n < 0) {
// cancel_fd
kill(pid, SIGKILL);
killed_by_us = true;
break;
} else {
char buf[4096];
ssize_t r = read(comm_pipe[n][0], buf, sizeof(buf));
if (r < 0 && errno == EINTR)
continue;
if (r > 0 && opts->fds[n].on_read)
opts->fds[n].on_read(opts->fds[n].on_read_ctx, buf, r);
if (r <= 0)
SAFE_CLOSE(comm_pipe[n][0]);
}
}
}
}
// Note: it can happen that a child process closes the pipe, but does not
// terminate yet. In this case, we would have to run waitpid() in
// a separate thread and use pthread_cancel(), or use other weird
// and laborious tricks in order to react to mp_cancel.
// So this isn't handled yet.
while (waitpid(pid, &status, 0) < 0 && errno == EINTR) {}
done:
if (fa_destroy)
posix_spawn_file_actions_destroy(&fa);
for (int n = 0; n < opts->num_fds; n++) {
SAFE_CLOSE(comm_pipe[n][0]);
SAFE_CLOSE(comm_pipe[n][1]);
}
SAFE_CLOSE(devnull);
if (!spawned || (WIFEXITED(status) && WEXITSTATUS(status) == 127)) {
res->error = MP_SUBPROCESS_EINIT;
} else if (WIFEXITED(status)) {
res->exit_status = WEXITSTATUS(status);
} else if (killed_by_us) {
res->error = MP_SUBPROCESS_EKILLED_BY_US;
} else {
res->error = MP_SUBPROCESS_EGENERIC;
}
}
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