Programmes de lancement et de contrôle de mon site en FastCGI

control.c

#include <stdlib.h>
#include <stdio.h>

#include <unistd.h>
#include <sys/types.h>
#include <signal.h>

char* arg0;

void drop_privileges() {
	if(setreuid(geteuid(), -1) == -1) {
		perror(arg0);
		exit(5);
	}
	if(setregid(getegid(), -1) == -1) {
		perror(arg0);
		exit(5);
	}
}

void usage(char *arg0) {
	printf("Usage: %s stop|restart|pause|resume\n", arg0);
}

int main(int argc, char** argv) {
	arg0 = argv[0];

	if(argc != 2) {
		usage(argv[0]);
		exit(1);
	}

	// Oubli de l'uid et du gid réels
	drop_privileges();

	// Récupération du pid
	char pidstr[10];
	FILE* pidfile = fopen("/run/fastcgi/alliance-rainbow.pid", "r");
	if(pidfile == NULL) {
		perror(argv[0]);
		exit(2);
	}

	int nbRead = fread(pidstr, sizeof(char), 9, pidfile);
	fclose(pidfile);
	pidstr[nbRead] = '\0';

	pid_t pid = (pid_t) strtoimax(pidstr, NULL, 10);

	// Choix du signal
	if(strcmp(argv[1], "stop") == 0) {
		kill(pid, SIGTERM);
	}
	else if(strcmp(argv[1], "restart") == 0) {
		kill(pid, SIGUSR1);
	}
	else if(strcmp(argv[1], "pause") == 0) {
		kill(pid, SIGUSR2);
	}
	else if(strcmp(argv[1], "resume") == 0) {
		kill(pid, SIGCONT);
	}
	else {
		usage(argv[0]);
		exit(1);
	}

	return 0;
}

start.c

#include <stdlib.h>
#include <stdio.h>
#include <stddef.h>

#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <signal.h>
#include <fcntl.h>
#include <pwd.h>
#include <grp.h>
#include <time.h>
#include <errno.h>

#define UNIX_PATH_MAX 108

char *arg0;
int shutdowning = 0;
int pidMain = -1, pidAjax = -1;

/* ---------- Fonctions d'initialisation ---------- */

void drop_privileges() {
	if(setreuid(geteuid(), -1) == -1) {
		perror(arg0);
		exit(5);
	}
	if(setregid(getegid(), -1) == -1) {
		perror(arg0);
		exit(5);
	}
}

void daemonize() {
	if(daemon(1, 1) == -1) {
		perror(arg0);
		exit(6);
	}
}

void mkPidfile() {
	FILE *pidfile = fopen("/run/fastcgi/alliance-rainbow.pid", "w");
	if(!pidfile) {
		perror(arg0);
		exit(7);
	}
	fprintf(pidfile, "%d", getpid());
	fclose(pidfile);
}

void rmPidfile() {
	unlink("/run/fastcgi/alliance-rainbow.pid");
}

int openSocket(char *path) {
	int pathlen = strlen(path);
	if(pathlen + 1 > UNIX_PATH_MAX) {
		fprintf(stderr, "Nom de socket trop long\n");
		exit(7);
	}

	int fd = socket(AF_UNIX, SOCK_STREAM, 0);

	struct sockaddr_un addr;
	addr.sun_family = AF_UNIX;
	strncpy(addr.sun_path, path, UNIX_PATH_MAX);

	int len = offsetof(struct sockaddr_un, sun_path) + pathlen + 1;
	unlink(path);

	if(bind(fd, (struct sockaddr*)&addr, len) == -1) {
		perror(arg0);
		exit(8);
	}
	if(listen(fd, 20) == -1) {
		perror(arg0);
		exit(8);
	}

	chmod(path, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);

	return fd;
}

void closeSocket(int fd, char *path) {
	close(fd);
	unlink(path);
}


/* ------------- Fonction de lancement ------------ */

pid_t spawn(char *path, int sock) {
	pid_t pid = fork();
	if(pid == -1) {
		perror(arg0);
		exit(9);
	}

	if(pid != 0) {
		return pid;
	}

	dup2(sock, STDIN_FILENO);

	execl(path, path, (char*)NULL);

	perror(path);
	exit(9);
}

void msg(char *msg) {
	time_t tim =  time(NULL);
	struct tm *loc_tim = localtime(&tim);

	char dat[18];
	if(strftime(dat, 18, "%d/%m/%y %H:%M:%S", loc_tim) == 0) {
		dat[0] = '\0';
	}

	printf("[%s] %s\n", dat, msg);
}

/* ------------ Gestionnaires de signal ----------- */

void init_shutdown(int sig) {
	msg("Shutdown");
	shutdowning = 1;
	if(pidMain > 0) kill(pidMain, SIGUSR1);
	if(pidAjax > 0) kill(pidAjax, SIGUSR1);
}

void restart(int sig) {
	msg("Restart");
	if(pidMain > 0) kill(pidMain, SIGUSR1);
	if(pidAjax > 0) kill(pidAjax, SIGUSR1);
}

void enter_pause(int sig) {
	msg("Pause");

	sigset_t set;
	sigemptyset(&set);
	sigaddset(&set, SIGCHLD);
	sigprocmask(SIG_SETMASK, &set, NULL);

	if(pidMain > 0) {
		kill(pidMain, SIGUSR1);
	}
	if(pidAjax > 0) {
		kill(pidAjax, SIGUSR1);
	}

	sigsuspend(&set);

	msg("Resume");
	sigemptyset(&set);
	sigprocmask(SIG_SETMASK, &set, NULL);
}

void resume(int sig) {
}

void register_signals() {
	struct sigaction act;
	sigset_t set;
	sigemptyset(&set);
	act.sa_mask = set;
	act.sa_flags = 0;

	act.sa_handler = init_shutdown;
	sigaction(SIGTERM, &act, NULL);
	sigaction(SIGINT, &act, NULL);

	act.sa_handler = restart;
	sigaction(SIGUSR1, &act, NULL);

	act.sa_handler = enter_pause;
	sigaction(SIGUSR2, &act, NULL);

	act.sa_handler = resume;
	sigaction(SIGCONT, &act, NULL);
}


/* ------------------------------------------------ */

int main(int argc, char** argv) {
	arg0 = argv[0];

	// Initialisation
	drop_privileges();
	daemonize();
	mkPidfile();
	register_signals();
	
	fcntl(STDOUT_FILENO, F_SETFD, FD_CLOEXEC);
	fcntl(STDERR_FILENO, F_SETFD, FD_CLOEXEC);

	// Création des sockets
	int sockMain = openSocket("/run/fastcgi/alliance-rainbow.main.sock");
	time_t timeMain = time(NULL);
	int nbDeathsMain = 0;

	int sockAjax = openSocket("/run/fastcgi/alliance-rainbow.ajax.sock");
	time_t timeAjax = time(NULL);
	int nbDeathsAjax = 0;

	// Premier lancement
	pidMain = spawn("./main.rb", sockMain);
	pidAjax = spawn("./ajax.rb", sockAjax);

	// Boucle principale
	while(pidMain != -1 || pidAjax != -1) {
		pid_t proc = wait(NULL);
		time_t curTime = time(NULL);

		if(proc == pidMain) {
			pidMain = -1;

			if(!shutdowning) {
				msg("Main est mort, longue vie à Main !");
				if(curTime - timeMain <= 10) {
					nbDeathsMain++;
					if(nbDeathsMain == 3) {
						msg("Main meurt trop vite, mise en pause");
						enter_pause(SIGUSR2);
					}
				}
				else {
					timeMain = curTime;
					nbDeathsMain = 1;
				}

				pidMain = spawn("./main.rb", sockMain);
			}
		}
		else if(proc == pidAjax) {
			pidAjax = -1;

			if(!shutdowning) {
				msg("Ajax est mort, longue vie à Ajax !");
				if(curTime - timeAjax <= 10) {
					nbDeathsAjax++;
					if(nbDeathsAjax == 3) {
						msg("Ajax meurt trop vite, désactivation de ce worker");
						continue;
					}
				}
				else {
					timeAjax = curTime;
					nbDeathsAjax = 1;
				}

				pidAjax = spawn("./ajax.rb", sockAjax);
			}
		}
	}

	// Désinitialisation
	closeSocket(sockMain, "/run/fastcgi/alliance-rainbow.main.sock");
	closeSocket(sockAjax, "/run/fastcgi/alliance-rainbow.ajax.sock");
	rmPidfile();
}