static void
babysit (int exit_with_session,
pid_t child_pid,
int read_bus_pid_fd) /* read pid from here */
{
DBusEnsureStandardFdsFlags flags;
int ret;
const char *s;
verbose ("babysitting, exit_with_session = %d, child_pid = %ld, read_bus_pid_fd = %d\n",
exit_with_session, (long) child_pid, read_bus_pid_fd);
/* We chdir ("/") since we are persistent and daemon-like, and fork
* again so dbus-launch can reap the parent. However, we don't
* setsid() or close fd 0 because the idea is to remain attached
* to the tty and the X server in order to kill the message bus
* when the session ends.
*/
if (chdir ("/") < 0)
{
fprintf (stderr, "Could not change to root directory: %s\n",
strerror (errno));
exit (1);
}
flags = DBUS_FORCE_STDOUT_NULL;
if (!exit_with_session)
flags |= DBUS_FORCE_STDIN_NULL;
s = getenv ("DBUS_DEBUG_OUTPUT");
if (s == NULL || *s == '\0')
flags |= DBUS_FORCE_STDERR_NULL;
/* Close stdout/stderr so we don't block an "eval" or otherwise
* lock up. stdout is still chaining through to dbus-launch
* and in turn to the parent shell.
*/
if (!_dbus_ensure_standard_fds (flags, &s))
{
fprintf (stderr, "%s: %s\n", s, strerror (errno));
exit (1);
}
ret = fork ();
if (ret < 0)
{
fprintf (stderr, "fork() failed in babysitter: %s\n",
strerror (errno));
exit (1);
}
if (ret > 0)
{
/* Parent reaps pre-fork part of bus daemon, then exits and is
* reaped so the babysitter isn't a zombie
*/
verbose ("=== Babysitter's intermediate parent continues again\n");
if (do_waitpid (child_pid) < 0)
{
/* shouldn't happen */
fprintf (stderr, "Failed waitpid() waiting for bus daemon's parent\n");
exit (1);
}
verbose ("Babysitter's intermediate parent exiting\n");
exit (0);
}
/* Child continues */
verbose ("=== Babysitter process created\n");
verbose ("Reading PID from bus\n");
switch (read_pid (read_bus_pid_fd, &bus_pid_to_kill))
{
case READ_STATUS_OK:
break;
case READ_STATUS_EOF:
fprintf (stderr, "EOF in dbus-launch reading PID from bus daemon\n");
exit (1);
break;
case READ_STATUS_ERROR:
fprintf (stderr, "Error in dbus-launch reading PID from bus daemon: %s\n",
strerror (errno));
exit (1);
break;
}
verbose ("Got PID %ld from daemon\n",
(long) bus_pid_to_kill);
if (exit_with_session)
{
/* Bus is now started and launcher has needed info;
* we connect to X display and tty and wait to
* kill bus if requested.
*/
kill_bus_when_session_ends ();
}
verbose ("Babysitter exiting\n");
exit (0);
}
static void
babysit (int exit_with_session,
pid_t child_pid,
int read_bus_pid_fd, /* read pid from here */
int write_bus_pid_fd) /* forward pid to here */
{
int ret;
#define MAX_PID_LEN 64
char buf[MAX_PID_LEN];
long val;
char *end;
int dev_null_fd;
const char *s;
verbose ("babysitting, exit_with_session = %d, child_pid = %ld, read_bus_pid_fd = %d, write_bus_pid_fd = %d\n",
exit_with_session, (long) child_pid, read_bus_pid_fd, write_bus_pid_fd);
/* We chdir ("/") since we are persistent and daemon-like, and fork
* again so dbus-launch can reap the parent. However, we don't
* setsid() or close fd 0 because the idea is to remain attached
* to the tty and the X server in order to kill the message bus
* when the session ends.
*/
if (chdir ("/") < 0)
{
fprintf (stderr, "Could not change to root directory: %s\n",
strerror (errno));
exit (1);
}
/* Close stdout/stderr so we don't block an "eval" or otherwise
* lock up. stdout is still chaining through to dbus-launch
* and in turn to the parent shell.
*/
dev_null_fd = open ("/dev/null", O_RDWR);
if (dev_null_fd >= 0)
{
if (!exit_with_session)
dup2 (dev_null_fd, 0);
dup2 (dev_null_fd, 1);
s = getenv ("DBUS_DEBUG_OUTPUT");
if (s == NULL || *s == '\0')
dup2 (dev_null_fd, 2);
}
else
{
fprintf (stderr, "Failed to open /dev/null: %s\n",
strerror (errno));
/* continue, why not */
}
ret = fork ();
if (ret < 0)
{
fprintf (stderr, "fork() failed in babysitter: %s\n",
strerror (errno));
exit (1);
}
if (ret > 0)
{
/* Parent reaps pre-fork part of bus daemon, then exits and is
* reaped so the babysitter isn't a zombie
*/
verbose ("=== Babysitter's intermediate parent continues again\n");
if (do_waitpid (child_pid) < 0)
{
/* shouldn't happen */
fprintf (stderr, "Failed waitpid() waiting for bus daemon's parent\n");
exit (1);
}
verbose ("Babysitter's intermediate parent exiting\n");
exit (0);
}
/* Child continues */
verbose ("=== Babysitter process created\n");
verbose ("Reading PID from daemon\n");
/* Now read data */
switch (read_line (read_bus_pid_fd, buf, MAX_PID_LEN))
{
case READ_STATUS_OK:
break;
case READ_STATUS_EOF:
fprintf (stderr, "EOF reading PID from bus daemon\n");
exit (1);
break;
case READ_STATUS_ERROR:
fprintf (stderr, "Error reading PID from bus daemon: %s\n",
strerror (errno));
exit (1);
break;
}
end = NULL;
val = strtol (buf, &end, 0);
if (buf == end || end == NULL)
{
fprintf (stderr, "Failed to parse bus PID \"%s\": %s\n",
buf, strerror (errno));
exit (1);
}
bus_pid_to_kill = val;
verbose ("Got PID %ld from daemon\n",
(long) bus_pid_to_kill);
/* Write data to launcher */
write_pid (write_bus_pid_fd, bus_pid_to_kill);
close (write_bus_pid_fd);
if (exit_with_session)
{
/* Bus is now started and launcher has needed info;
* we connect to X display and tty and wait to
* kill bus if requested.
*/
kill_bus_when_session_ends ();
}
verbose ("Babysitter exiting\n");
exit (0);
}
