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#define _POSIX_C_SOURCE 200809L
#include <signal.h>
#include <stdio.h>
#include <sys/signalfd.h>
#include <sys/wait.h>
#include <unistd.h>
#include "config.h"
static void reap(void) {
int status;
while (waitpid(-1, &status, WNOHANG) > 0) {
}
}
int main(void) {
int sigfd = -1;
pid_t pid = -1;
sigset_t set;
if (getpid() != 1) {
fprintf(stderr, "4init - you need to run this as PID 1...\n");
return 1;
}
sigfillset(&set);
sigdelset(&set, SIGILL);
sigdelset(&set, SIGTRAP);
sigdelset(&set, SIGBUS);
sigdelset(&set, SIGFPE);
sigdelset(&set, SIGSEGV);
if (sigprocmask(SIG_SETMASK, &set, NULL) < 0) {
perror("sigprocmask");
return 1;
}
sigfd = signalfd(-1, &set, SFD_CLOEXEC);
if (sigfd < 0) {
perror("signalfd");
return 1;
}
pid = fork();
if (pid < 0) {
perror("fork");
return 1;
}
if (pid == 0) {
sigset_t empty_set;
sigemptyset(&empty_set);
sigprocmask(SIG_SETMASK, &empty_set, NULL);
if (setsid() == -1) {
perror("setsid");
}
close(sigfd);
execve(rc_path, rc_argv, rc_envp);
perror("execve");
_exit(1);
} else {
struct signalfd_siginfo fdsi;
reap();
for (;;) {
if (read(sigfd, &fdsi, sizeof(fdsi)) == sizeof(fdsi)) {
switch (fdsi.ssi_signo) {
case SIGCHLD:
reap();
break;
}
}
}
}
}
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