launchd.c

/* THIS IS VERY DANGEROUS PLEASE DON'T USE THIS (only tested once) */

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <time.h>
#include <spawn.h>
#include <string.h>

#define LAUNCHD "/sbin/launchd.real"
#define REAL "/sbin/haxx"

static const char __unused fakelaunchd[] = "fakelaunchd";
char* real_argv[] = { "LAUNCHD_HAXX", NULL };

int main (int argc, char* argv[], char* envp[]) {
	if (getpid() != 1) {
		fprintf(stderr, "fakelaunchd cannot be run directly.\n");
		exit(1);
	}
	int fd_console = open("/dev/console",O_RDWR,0);
    dup2(fd_console,0);
    dup2(fd_console,1);
    dup2(fd_console,2);
	for (uint8_t i = 0; i < 10; i++) {
		printf("============ WE ARE PID 1 ============\n");
	}
	close(fd_console);
	close(0);
	close(1);
	close(2);
	pid_t pid = fork();
	if (pid == 0) {
      execve(REAL, real_argv, envp);
      fprintf(stderr, "cannot execute %s!g: %s... bailing\n", REAL, strerror(errno));
	  exit(1);
	} else {
      execve(LAUNCHD, argv, envp);
	  fprintf(stderr, "cannot execute %s!g: %s... spinning\n", LAUNCHD, strerror(errno));
	  while (1) {
		sleep(__INT_MAX__);
	  }
	}
	exit(42);
}