// Syscall API
int task_signal_syscall(task_t* source, isf_t* state, int target_pid, int sig) {
task_t* target_task = scheduler_find(target_pid);
if(!target_task) {
sc_errno = ESRCH;
return -1;
}
if(target_task->euid != source->euid) {
sc_errno = EPERM;
return -1;
}
/* POSIX: "If sig is 0 (the null signal), error checking is performed but
* no signal is actually sent. The null signal can be used to check the
* validity of pid."
*/
if(!sig) {
return 0;
}
return task_signal(target_task, source, sig, state);
}
__sighandler_t sys_signal(int signum, __sighandler_t handler) {
return task_signal(CurrentTask, signum, handler);
}
int
dmon_main (int argc, char **argv)
{
w_io_t *pidfile_io = NULL;
char *opts_env = NULL;
bool success;
unsigned i, consumed;
/* Check for "-C configfile" given in the command line. */
if (argc > 2 && ((argv[1][0] == '-' &&
argv[1][1] == 'C' &&
argv[1][2] == '\0') ||
!strcmp ("--config", argv[1])))
{
w_lobj w_io_t *cfg_io = NULL;
char *err_msg = NULL;
if ((cfg_io = w_io_unix_open (argv[2], O_RDONLY, 0)) == NULL)
w_die ("$s: Could not open file '$s', $E\n", argv[0], argv[2]);
success = w_opt_parse_io (dmon_options, cfg_io, &err_msg);
if (!success || err_msg)
w_die ("$s: Error parsing '$s' at line $s\n", argv[0], argv[2], err_msg);
replace_args_shift (2, &argc, &argv);
}
if ((opts_env = getenv ("DMON_OPTIONS")) != NULL)
replace_args_string (opts_env, &argc, &argv);
i = consumed = w_opt_parse (dmon_options, NULL, NULL,
"cmd [cmd-options] [ -- "
"log-cmd [log-cmd-options]]",
argc, argv);
W_DEBUG ("w_opt_parse consumed $I arguments\n", consumed);
if (workdir_path) {
if (chdir (workdir_path) != 0)
w_die ("$s: Cannot use '$s' as work directory, $E\n", argv[0], workdir_path);
}
if (status_path) {
status_io = w_io_unix_open (status_path, O_WRONLY | O_CREAT | O_APPEND, 0666);
if (!status_io)
w_die ("$s: Cannot open '$s' for writing, $E\n", argv[0], status_path);
}
if (cmd_interval && success_exit)
w_die ("$s: Options '-i' and '-1' cannot be used together.\n", argv[0]);
if (load_enabled && almost_zerof (load_low))
load_low = load_high / 2.0f;
cmd_task.argv = argv + consumed;
/* Skip over until "--" is found */
while (i < (unsigned) argc && strcmp (argv[i], "--") != 0) {
cmd_task.argc++;
i++;
}
/* There is a log command */
if (i < (unsigned) argc && strcmp (argv[i], "--") == 0) {
log_task.argc = argc - cmd_task.argc - consumed - 1;
log_task.argv = argv + argc - log_task.argc;
log_task.argv[log_task.argc] = NULL;
}
cmd_task.argv[cmd_task.argc] = NULL;
if (log_task.argc > 0) {
if (pipe (log_fds) != 0) {
w_die ("$s: Cannot create pipe: $E\n", argv[0]);
}
W_DEBUG ("pipe_read = $i, pipe_write = $i\n", log_fds[0], log_fds[1]);
fd_cloexec (log_fds[0]);
fd_cloexec (log_fds[1]);
}
#ifdef _DEBUG_PRINT
{
char **xxargv = cmd_task.argv;
w_io_format (w_stderr, "cmd:");
while (*xxargv) w_io_format (w_stderr, " $s", *xxargv++);
w_io_format (w_stderr, "\n");
if (log_enabled) {
char **xxargv = log_task.argv;
w_io_format (w_stderr, "log:");
while (*xxargv) w_io_format (w_stderr, " $c", *xxargv++);
w_io_format (w_stderr, "\n");
}
}
#endif /* _DEBUG_PRINT */
if (cmd_task.argc == 0)
w_die ("$s: No command to run given.\n", argv[0]);
if (pidfile_path) {
pidfile_io = w_io_unix_open (pidfile_path,
O_TRUNC | O_CREAT | O_WRONLY,
0666);
if (!pidfile_io) {
w_die ("$s: cannot open '$s' for writing: $E\n",
argv[0], pidfile_path);
}
}
if (!nodaemon)
become_daemon ();
/* We have a valid file descriptor: write PID */
if (pidfile_io) {
w_io_result_t r = w_io_format (pidfile_io,
"$L\n",
(unsigned long) getpid ());
if (w_io_failed (r))
W_WARN ("I/O error writing to PID file: $E\n");
w_obj_unref (pidfile_io);
}
setup_signals ();
alarm (cmd_timeout);
cmd_task.write_fd = log_fds[1];
log_task.read_fd = log_fds[0];
while (running) {
W_DEBUG (">>> loop iteration\n");
if (check_child) {
int retcode = reap_and_check ();
/*
* Wait the specified timeout but DO NOT use safe_sleep(): here
* we want an interruptible sleep-wait so reaction to signals is
* quick, which we definitely want for SIGINT/SIGTERM.
*/
if (cmd_interval && !success_exit && retcode == 0) {
int retval;
struct timespec ts;
ts.tv_sec = cmd_interval;
ts.tv_nsec = 0;
do {
retval = nanosleep (&ts, &ts);
W_DEBUGC (" nanosleep -> $i\n", retval);
} while (retval == -1 && errno == EINTR && running);
}
/*
* Either handling signals which interrupt the previous loop,
* or reap_and_check() may request stopping on successful exit
*/
if (!running) {
task_action_queue (&cmd_task, A_NONE);
break;
}
}
task_action_dispatch_and_write_status ("cmd", &cmd_task);
if (log_enabled)
task_action_dispatch_and_write_status ("log", &log_task);
if (load_enabled) {
double load_cur;
W_DEBUGC (" checking load after sleeping 1s\n");
interruptible_sleep (1);
if (getloadavg (&load_cur, 1) == -1)
W_WARN ("getloadavg() failed: $E\n");
if (paused) {
/* If the current load dropped below load_low -> resume */
if (load_cur <= load_low) {
W_DEBUGC (" resuming...\n");
task_signal (&cmd_task, SIGCONT);
write_status ("cmd resume $L\n", (unsigned long) cmd_task.pid);
paused = 0;
}
}
else {
/* If the load went above load_high -> pause */
if (load_cur > load_high) {
W_DEBUGC (" pausing...\n");
task_signal (&cmd_task, SIGSTOP);
write_status ("cmd pause $L\n", (unsigned long) cmd_task.pid);
paused = 1;
}
}
}
else {
/* Wait for signals to arrive. */
W_DEBUGC (" waiting for signals to come...\n");
pause ();
}
}
W_DEBUG ("exiting gracefully...\n");
if (cmd_task.pid != NO_PID) {
write_status ("cmd stop $L\n", (unsigned long) cmd_task.pid);
task_action (&cmd_task, A_STOP);
}
if (log_enabled && log_task.pid != NO_PID) {
write_status ("log stop $L\n", (unsigned long) log_task.pid);
task_action (&log_task, A_STOP);
}
if (status_io) {
w_obj_unref (status_io);
status_io = NULL;
}
exit (EXIT_SUCCESS);
}
