A fast, lightweight and minimalistic Wayland terminal emulator
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 
 

158 lines
3.7 KiB

#include "slave.h"
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <assert.h>
#include <signal.h>
#include <sys/stat.h>
#include <fcntl.h>
#define LOG_MODULE "slave"
#define LOG_ENABLE_DBG 0
#include "log.h"
#include "tokenize.h"
static void
slave_exec(int ptmx, char *const argv[], int err_fd)
{
int pts = -1;
const char *pts_name = ptsname(ptmx);
if (grantpt(ptmx) == -1) {
LOG_ERRNO("failed to grantpt()");
goto err;
}
if (unlockpt(ptmx) == -1) {
LOG_ERRNO("failed to unlockpt()");
goto err;
}
close(ptmx);
ptmx = -1;
if (setsid() == -1) {
LOG_ERRNO("failed to setsid()");
goto err;
}
pts = open(pts_name, O_RDWR);
if (pts == -1) {
LOG_ERRNO("failed to open pseudo terminal slave device");
goto err;
}
if (dup2(pts, STDIN_FILENO) == -1 ||
dup2(pts, STDOUT_FILENO) == -1 ||
dup2(pts, STDERR_FILENO) == -1)
{
LOG_ERRNO("failed to dup stdin/stdout/stderr");
goto err;
}
close(pts);
pts = -1;
execvp(argv[0], argv);
err:
(void)!write(err_fd, &errno, sizeof(errno));
if (pts != -1)
close(pts);
if (ptmx != -1)
close(ptmx);
close(err_fd);
_exit(errno);
}
pid_t
slave_spawn(int ptmx, int argc, const char *cwd, char *const *argv,
const char *term_env, const char *conf_shell)
{
int fork_pipe[2];
if (pipe2(fork_pipe, O_CLOEXEC) < 0) {
LOG_ERRNO("failed to create pipe");
return -1;
}
pid_t pid = fork();
switch (pid) {
case -1:
LOG_ERRNO("failed to fork");
close(fork_pipe[0]);
close(fork_pipe[1]);
return -1;
case 0:
/* Child */
close(fork_pipe[0]); /* Close read end */
chdir(cwd);
/* Restore signals */
const struct sigaction sa = {.sa_handler = SIG_DFL};
if (sigaction(SIGINT, &sa, NULL) < 0 ||
sigaction(SIGTERM, &sa, NULL) < 0 ||
sigaction(SIGHUP, &sa, NULL) < 0)
{
const int _errno = errno;
LOG_ERRNO_P("failed to restore signals", errno);
(void)!write(fork_pipe[1], &_errno, sizeof(_errno));
_exit(_errno);
}
setenv("TERM", term_env, 1);
char **_shell_argv = NULL;
char *const *shell_argv = argv;
if (argc == 0) {
char *shell_copy = strdup(conf_shell);
if (!tokenize_cmdline(shell_copy, &_shell_argv)) {
free(shell_copy);
(void)!write(fork_pipe[1], &errno, sizeof(errno));
_exit(0);
}
shell_argv = _shell_argv;
}
slave_exec(ptmx, shell_argv, fork_pipe[1]);
assert(false);
break;
default: {
close(fork_pipe[1]); /* Close write end */
LOG_DBG("slave has PID %d", pid);
int _errno;
static_assert(sizeof(errno) == sizeof(_errno), "errno size mismatch");
ssize_t ret = read(fork_pipe[0], &_errno, sizeof(_errno));
close(fork_pipe[0]);
if (ret < 0) {
LOG_ERRNO("failed to read from pipe");
return -1;
} else if (ret == sizeof(_errno)) {
LOG_ERRNO_P(
"%s: failed to execute", _errno, argc == 0 ? conf_shell : argv[0]);
return -1;
} else
LOG_DBG("%s: successfully started", conf_shell);
int fd_flags;
if ((fd_flags = fcntl(ptmx, F_GETFD)) < 0 ||
fcntl(ptmx, F_SETFD, fd_flags | FD_CLOEXEC) < 0)
{
LOG_ERRNO("failed to set FD_CLOEXEC on ptmx");
return -1;
}
break;
}
}
return pid;
}