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daemon_with_notify
daemonize a process, can wait for child to signal readiness
Stewart Smith <stewart@flamingspork.com>
Daemons should detach themselves thoroughly from the process which launched them, and not prevent any filesystems from being unmounted. daemonize() helps with the process.
Daemon-with-notify is different in that the child can send a SIGUSR1 to the parent to indicate it has started (e.g. after memory allocation and other things that may fail) so that the parent can return a success or failing exit code and init scripts can pick this up easily.
#include <ccan/daemon_with_notify/daemon_with_notify.h>
#include <ccan/str/str.h>
#include <err.h>
#include <unistd.h>
#include <stdlib.h>
static void usage(const char *name)
{
errx(1, "Usage: %s [--daemonize]\n", name);
}
// Wait for a minute, possibly as a daemon.
int main(int argc, char *argv[])
{
if (argc != 1) {
if (argc == 2 && streq(argv[1], "--daemonize")) {
if (!daemonize(1, 1, 1))
err(1, "Failed to become daemon");
} else
usage(argv[1]);
}
sleep(10); // do some init here
daemon_is_ready();
sleep(20); // will be done in child, detached from parent
exit(0);
}
BSD (3 clause)