finit.c (1548B)
1 /* See LICENSE file for copyright and license details. */ 2 #include <common.h> 3 #include <fmt.h> 4 #include <signal.h> 5 #include <stdio.h> 6 #include <stdlib.h> 7 #include <sys/types.h> 8 #include <sys/wait.h> 9 #include <unistd.h> 10 11 #define TIMEO 30 12 13 static void sighalt(void); 14 static void sigreap(void); 15 static void sigreboot(void); 16 17 static const struct { 18 int sig; 19 void (*handler)(void); 20 } sigmap[] = { 21 { SIGTERM, sighalt }, 22 { SIGINT, sigreboot }, 23 { SIGCHLD, sigreap }, 24 { SIGALRM, sigreap }, 25 }; 26 27 static sigset_t set; 28 static pid_t run_pid; 29 30 static char start_command[] = "/etc/fiss/run"; 31 static char stop_command[] = "/etc/fiss/halt"; 32 33 int main(void) { 34 int signal; 35 36 if (getpid() != 1) 37 return 1; 38 39 chdir("/"); 40 sigfillset(&set); 41 sigprocmask(SIG_BLOCK, &set, NULL); 42 43 switch (run_pid = fork()) { 44 case 0: 45 sigprocmask(SIG_UNBLOCK, &set, NULL); 46 setsid(); 47 execl(start_command, start_command, NULL); 48 perror("execvp"); 49 _exit(1); 50 case -1: 51 perror("fork"); 52 } 53 54 while (1) { 55 alarm(TIMEO); 56 sigwait(&set, &signal); 57 for (int i = 0; i < (int) LEN(sigmap); i++) { 58 if (sigmap[i].sig == signal) { 59 sigmap[i].handler(); 60 break; 61 } 62 } 63 } 64 65 /* not reachable */ 66 return 0; 67 } 68 69 static void 70 sighalt(void) { 71 execl(stop_command, stop_command, "halt", NULL); 72 } 73 74 static void 75 sigreboot(void) { 76 execl(stop_command, stop_command, "reboot", NULL); 77 } 78 79 static void 80 sigreap(void) { 81 pid_t pid; 82 while ((pid = waitpid(-1, NULL, WNOHANG)) > 0) 83 if (pid == run_pid) { 84 fprint(1, "run stopped, halting\n"); 85 sighalt(); 86 } 87 alarm(TIMEO); 88 }