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/*
* openrc-init.c
* This is the init process (pid 1) for OpenRC.
*
* This is based on code written by James Hammons <jlhamm@acm.org>, so
* I would like to publically thank him for his work.
*/
/*
* Copyright (c) 2017 The OpenRC Authors.
* See the Authors file at the top-level directory of this distribution and
* https://github.com/OpenRC/openrc/blob/master/AUTHORS
*
* This file is part of OpenRC. It is subject to the license terms in
* the LICENSE file found in the top-level directory of this
* distribution and at https://github.com/OpenRC/openrc/blob/master/LICENSE
* This file may not be copied, modified, propagated, or distributed
* except according to the terms contained in the LICENSE file.
*/
#include <errno.h>
#include <signal.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/reboot.h>
#include <sys/wait.h>
#include "helpers.h"
#include "rc.h"
#include "version.h"
static const char *rc_default_runlevel = "default";
static pid_t do_openrc(const char *runlevel)
{
pid_t pid;
sigset_t signals;
pid = fork();
switch(pid) {
case -1:
perror("fork");
break;
case 0:
setsid();
/* unblock all signals */
sigemptyset(&signals);
sigprocmask(SIG_SETMASK, &signals, NULL);
printf("Starting %s runlevel\n", runlevel);
execl("/sbin/openrc", "/sbin/openrc", runlevel, NULL);
perror("exec");
break;
default:
break;
}
return pid;
}
static void init(const char *default_runlevel)
{
const char *runlevel = NULL;
pid_t pid;
pid = do_openrc("sysinit");
waitpid(pid, NULL, 0);
pid = do_openrc("boot");
waitpid(pid, NULL, 0);
if (default_runlevel)
runlevel = default_runlevel;
else
runlevel = rc_conf_value("rc_default_runlevel");
if (!runlevel)
runlevel = rc_default_runlevel;
if (!rc_runlevel_exists(runlevel)) {
printf("%s is an invalid runlevel\n", runlevel);
runlevel = rc_default_runlevel;
}
pid = do_openrc(runlevel);
waitpid(pid, NULL, 0);
}
static void handle_reexec(char *my_name)
{
execl(my_name, my_name, "reexec", NULL);
return;
}
static void handle_shutdown(const char *runlevel, int cmd)
{
pid_t pid;
pid = do_openrc(runlevel);
while (waitpid(pid, NULL, 0) != pid);
printf("Sending the final term signal\n");
kill(-1, SIGTERM);
sleep(3);
printf("Sending the final kill signal\n");
kill(-1, SIGKILL);
sync();
reboot(cmd);
}
static void handle_single(void)
{
pid_t pid;
pid = do_openrc("single");
while (waitpid(pid, NULL, 0) != pid);
}
static void reap_zombies(void)
{
pid_t pid;
for (;;) {
pid = waitpid(-1, NULL, WNOHANG);
if (pid == 0)
break;
else if (pid == -1) {
if (errno == ECHILD)
break;
perror("waitpid");
continue;
}
}
}
static void signal_handler(int sig)
{
switch(sig) {
case SIGINT:
handle_shutdown("reboot", RB_AUTOBOOT);
break;
case SIGCHLD:
reap_zombies();
break;
default:
printf("Unknown signal received, %d\n", sig);
break;
}
}
int main(int argc, char **argv)
{
char *default_runlevel;
char buf[2048];
int count;
FILE *fifo;
bool reexec = false;
sigset_t signals;
struct sigaction sa;
if (getpid() != 1)
return 1;
printf("OpenRC init version %s starting\n", VERSION);
if (argc > 1)
default_runlevel = argv[1];
else
default_runlevel = NULL;
if (default_runlevel && strcmp(default_runlevel, "reexec") == 0)
reexec = true;
/* block all signals we do not handle */
sigfillset(&signals);
sigdelset(&signals, SIGCHLD);
sigdelset(&signals, SIGINT);
sigprocmask(SIG_SETMASK, &signals, NULL);
/* install signal handler */
memset(&sa, 0, sizeof(sa));
sa.sa_handler = signal_handler;
sigaction(SIGCHLD, &sa, NULL);
sigaction(SIGINT, &sa, NULL);
reboot(RB_DISABLE_CAD);
if (! reexec)
init(default_runlevel);
if (mkfifo(RC_INIT_FIFO, 0600) == -1 && errno != EEXIST)
perror("mkfifo");
for (;;) {
/* This will block until a command is sent down the pipe... */
fifo = fopen(RC_INIT_FIFO, "r");
if (!fifo) {
if (errno != EINTR)
perror("fopen");
continue;
}
count = fread(buf, 1, 2048, fifo);
buf[count] = 0;
fclose(fifo);
printf("PID1: Received \"%s\" from FIFO...\n", buf);
if (strcmp(buf, "halt") == 0)
handle_shutdown("shutdown", RB_HALT_SYSTEM);
else if (strcmp(buf, "kexec") == 0)
handle_shutdown("reboot", RB_KEXEC);
else if (strcmp(buf, "poweroff") == 0)
handle_shutdown("shutdown", RB_POWER_OFF);
else if (strcmp(buf, "reboot") == 0)
handle_shutdown("reboot", RB_AUTOBOOT);
else if (strcmp(buf, "reexec") == 0)
handle_reexec(argv[0]);
else if (strcmp(buf, "single") == 0)
handle_single();
}
return 0;
}
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