static void mainloop(unsigned sleep_interval,
int pipe_to_child,
int pipe_from_child)
{
int child_ping_count = 0;
// NOTE: One should NOT do anything potentially blocking in the mainloop.
// Otherwise we run the risk of being late to kick the HW watchdogs.
while (run) {
// kick WD's right before sleep
dsme_wd_kick();
// sleep precisely
struct timespec remaining_sleep_time = { sleep_interval, 0 };
while (nanosleep(&remaining_sleep_time, &remaining_sleep_time) == -1 &&
errno == EINTR)
{
// interrupt could mean that someone wants to force a WD kick;
// also, we have to kick just before stopping running
dsme_wd_kick();
if (!run) {
goto done_running;
}
// interrupt may have come from the dsme server; consider it alive
child_ping_count = 0;
}
// kick WD's right after sleep
dsme_wd_kick();
// make sure the dsme server (the child) is alive
if (pong(pipe_from_child)) {
child_ping_count = 0;
} else if (child_ping_count >= DSME_MAXPING) {
// dsme server has failed to respond in due time
fprintf(stderr, ME "dsme-server nonresponsive; quitting\n");
run = false;
dsme_abnormal_exit = true;
goto done_running;
}
// ping the dsme server
ping(pipe_to_child);
++child_ping_count;
}
done_running:
return;
}
/**
@todo Possibility to alter priority of initial module somehow
*/
int main(int argc, char *argv[])
{
fprintf(stderr, "DSME %s starting up\n", STRINGIFY(PRG_VERSION));
// lock to ram (will not be inherited)
if (mlockall(MCL_FUTURE) == -1) {
fprintf(stderr, ME "Couldn't lock to RAM: %s\n", strerror(errno));
}
// do the first kick right away
if (!dsme_wd_init()) {
fprintf(stderr, ME "no WD's opened; WD kicking disabled\n");
}
dsme_wd_kick();
// set up signal handler
signal(SIGHUP, signal_handler);
signal(SIGINT, signal_handler);
signal(SIGTERM, signal_handler);
signal(SIGPIPE, signal_handler);
signal(SIGCHLD, signal_handler);
// protect from oom
if (!protect_from_oom()) {
fprintf(stderr, ME "Couldn't protect from oom: %s\n", strerror(errno));
}
// set priority/niceness (will be inherited)
if (setpriority(PRIO_PROCESS, 0, DSME_NICE) == -1) {
fprintf(stderr, ME "Couldn't set the priority: %s\n", strerror(errno));
}
// set scheduler (will be inherited)
struct sched_param sch;
memset(&sch, 0, sizeof(sch));
sch.sched_priority = sched_get_priority_max(DSME_HB_SCHEDULER);
if (sched_setscheduler(0, DSME_HB_SCHEDULER, &sch) == -1) {
fprintf(stderr, ME "Couldn't set the scheduler: %s\n", strerror(errno));
}
// parse command line options
int daemon = 0;
parse_options(argc, argv, &daemon);
// daemonize
if (daemon && daemonize() == -1) {
return EXIT_FAILURE;
}
// set running directory
if (chdir("/") == -1) {
fprintf(stderr, ME "chdir failed: %s\n", strerror(errno));
return EXIT_FAILURE;
}
// open communication pipes
int to_child[2];
int from_child[2];
if (pipe(to_child) != 0 || pipe(from_child) != 0) {
fprintf(stderr, ME "pipe failed: %s\n", strerror(errno));
return EXIT_FAILURE;
}
// fork and exec the dsme server
pid_t pid;
if ((pid = fork()) == -1) {
fprintf(stderr, ME "fork failed: %s\n", strerror(errno));
return EXIT_FAILURE;
} else if (pid == 0) {
// child
// TODO: lower priority
// TODO: restore scheduler
// child gets the pipes in stdin & stdout
if (dup2(to_child[0], STDIN_FILENO) != STDIN_FILENO) {
fprintf(stderr, ME "dup2 failed: %s\n", strerror(errno));
return EXIT_FAILURE;
}
if (dup2(from_child[1], STDOUT_FILENO) != STDOUT_FILENO) {
fprintf(stderr, ME "dup2 failed: %s\n", strerror(errno));
return EXIT_FAILURE;
}
// close all the other descriptors
int max_fd_count = getdtablesize();
if (max_fd_count == -1) {
max_fd_count = 256;
}
for (int i = 3; i < max_fd_count; ++i) {
(void)close(i);
}
// exec dsme server core
char* newargv[argc+1];
newargv[0] = (char*)DSME_SERVER_PATH;
for (int i = 1; i < argc; ++i) {
newargv[i] = argv[i];
}
newargv[argc] = 0;
execv(DSME_SERVER_PATH, newargv);
fprintf(stderr, ME "execv failed: %s\n", strerror(errno));
return EXIT_FAILURE;
} else {
// parent
// close child ends of pipes & set parent ends of pipes non-blocking
close(to_child[0]);
close(from_child[1]);
set_nonblocking(to_child[1]);
set_nonblocking(from_child[0]);
}
unsigned sleep_interval = DSME_HEARTBEAT_INTERVAL;
fprintf(stderr,
ME "Entering main loop, with %u s interval\n",
sleep_interval);
mainloop(sleep_interval, to_child[1], from_child[0]);
fprintf(stderr, ME "Exited main loop, quitting\n");
// also bring dsme server down
kill(pid, SIGTERM);
(void)waitpid(pid, 0, 0);
if (remove(DSME_PID_FILE) < 0) {
fprintf(stderr, ME "Couldn't remove lockfile\n");
}
return EXIT_SUCCESS;
}
/**
@todo Possibility to alter priority of initial module somehow
*/
int main(int argc, char *argv[])
{
fprintf(stderr, "DSME %s starting up\n", STRINGIFY(PRG_VERSION));
// do the first kick right away
if (!dsme_wd_init()) {
fprintf(stderr, ME "no WD's opened; WD kicking disabled\n");
}
dsme_wd_kick();
trap_terminating_signals();
// set up signal handler
signal(SIGHUP, signal_handler);
signal(SIGINT, signal_handler);
signal(SIGTERM, signal_handler);
signal(SIGPIPE, signal_handler);
signal(SIGCHLD, signal_handler);
#ifdef DSME_SYSTEMD_ENABLE
signal(SIGUSR1, signal_handler);
#endif
// protect from oom
if (!protect_from_oom()) {
fprintf(stderr, ME "Couldn't protect from oom: %s\n", strerror(errno));
}
// set priority/niceness (will be inherited)
if (setpriority(PRIO_PROCESS, 0, DSME_NICE) == -1) {
fprintf(stderr, ME "Couldn't set the priority: %s\n", strerror(errno));
}
// set scheduler (will be inherited)
struct sched_param sch;
memset(&sch, 0, sizeof(sch));
sch.sched_priority = sched_get_priority_max(DSME_HB_SCHEDULER);
if (sched_setscheduler(0, DSME_HB_SCHEDULER, &sch) == -1) {
fprintf(stderr, ME "Couldn't set the scheduler: %s\n", strerror(errno));
}
// lock to ram (will not be inherited)
if (mlockall(MCL_CURRENT|MCL_FUTURE) == -1) {
fprintf(stderr, ME "Couldn't lock to RAM: %s\n", strerror(errno));
}
// parse command line options
int daemon = 0;
parse_options(argc, argv, &daemon);
// daemonize
if (daemon && daemonize() == -1) {
return EXIT_FAILURE;
}
// set running directory
if (chdir("/") == -1) {
fprintf(stderr, ME "chdir failed: %s\n", strerror(errno));
return EXIT_FAILURE;
}
// open communication pipes
int to_child[2];
int from_child[2];
if (pipe(to_child) != 0 || pipe(from_child) != 0) {
fprintf(stderr, ME "pipe failed: %s\n", strerror(errno));
return EXIT_FAILURE;
}
// fork and exec the dsme server
pid_t pid;
if ((pid = fork()) == -1) {
fprintf(stderr, ME "fork failed: %s\n", strerror(errno));
return EXIT_FAILURE;
} else if (pid == 0) {
// child
// TODO: lower priority
// TODO: restore scheduler
// child gets the pipes in stdin & stdout
if (dup2(to_child[0], STDIN_FILENO) != STDIN_FILENO) {
fprintf(stderr, ME "dup2 failed: %s\n", strerror(errno));
_exit(EXIT_FAILURE);
}
if (dup2(from_child[1], STDOUT_FILENO) != STDOUT_FILENO) {
fprintf(stderr, ME "dup2 failed: %s\n", strerror(errno));
_exit(EXIT_FAILURE);
}
// close all the other descriptors
int max_fd_count = getdtablesize();
if (max_fd_count == -1) {
max_fd_count = 256;
}
for (int i = 3; i < max_fd_count; ++i) {
(void)close(i);
}
// exec dsme server core
char* newargv[argc+1];
newargv[0] = (char*)DSME_SERVER_PATH;
for (int i = 1; i < argc; ++i) {
newargv[i] = argv[i];
}
newargv[argc] = 0;
execv(DSME_SERVER_PATH, newargv);
fprintf(stderr,
ME "execv failed: %s: %s\n",
DSME_SERVER_PATH,
strerror(errno));
_exit(EXIT_FAILURE);
} else {
// parent
// close child ends of pipes & set parent ends of pipes non-blocking
close(to_child[0]);
close(from_child[1]);
set_nonblocking(to_child[1]);
set_nonblocking(from_child[0]);
}
/* Before entering the mainloop, clear wakelock that might be set if dsme
* is restarting after signal / watchdog pingpong failure */
release_restart_wakelock();
unsigned sleep_interval = DSME_HEARTBEAT_INTERVAL;
mainloop(sleep_interval, to_child[1], from_child[0]);
fprintf(stderr, ME "Exited main loop, quitting\n");
/* Get wakelock after exiting the mainloop, will be cleared
* if we make orderly normal exit */
obtain_restart_wakelock();
/* Bring down the dsme-server child process
*
* Note: The maximum duration we can spend here must be shorter
* than both hw watchdog kick period and the time systemd
* allows for dsme itself to exit.
*/
// kick watchdogs so we have time to wait for dsme-server to exit
dsme_wd_kick();
if( kill_and_wait(pid, SIGTERM, 8) || kill_and_wait(pid, SIGKILL, 3) ) {
// clear nowayout states and close watchdog files
dsme_wd_quit();
}
else {
// leave the nowayout states on so that we will get a wd reboot
// shortly after dsme exits, but kick the watchdogs one more time
// to give the system some time to make orderly shutdown
dsme_wd_kick();
fprintf(stderr, ME "dsme-server stop failed, leaving watchdogs"
" active\n");
dsme_abnormal_exit = true;
}
/* Remove the PID file */
if (remove(DSME_PID_FILE) < 0 && errno != ENOENT) {
fprintf(stderr, ME "Couldn't remove lockfile: %m\n");
}
/* Clear wakelock on normal, successful exit */
if( dsme_abnormal_exit )
fprintf(stderr, ME "abnormal exit, leaving wakelock active\n");
else
release_restart_wakelock();
fprintf(stderr, "DSME %s terminating\n", STRINGIFY(PRG_VERSION));
return dsme_abnormal_exit ? EXIT_FAILURE : EXIT_SUCCESS;
}