/*
 * Copyright (C) 2014-2017 Firejail Authors
 *
 * This file is part of firejail project
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "firejail.h"
#include <sys/stat.h>
#include <sys/wait.h>
#include <fcntl.h>
#include <sys/prctl.h>

void shut(pid_t pid) {
	EUID_ASSERT();

	pid_t parent = pid;
	// if the pid is that of a firejail  process, use the pid of a child process inside the sandbox
	EUID_ROOT();
	char *comm = pid_proc_comm(pid);
	EUID_USER();
	if (comm) {
		if (strcmp(comm, "firejail") == 0) {
			pid_t child;
			if (find_child(pid, &child) == 0) {
				pid = child;
				printf("Switching to pid %u, the first child process inside the sandbox\n", (unsigned) pid);
			}
		}
		else {
			fprintf(stderr, "Error: this is not a firejail sandbox\n");
			exit(1);
		}
		free(comm);
	}
	else
		errExit("/proc/PID/comm");

	// check privileges for non-root users
	uid_t uid = getuid();
	if (uid != 0) {
		uid_t sandbox_uid = pid_get_uid(pid);
		if (uid != sandbox_uid) {
			fprintf(stderr, "Error: permission is denied to shutdown a sandbox created by a different user.\n");
			exit(1);
		}
	}

	EUID_ROOT();
	printf("Sending SIGTERM to %u\n", pid);
	kill(pid, SIGTERM);

	// wait for not more than 10 seconds
	sleep(2);
	int monsec = 8;
	char *monfile;
	if (asprintf(&monfile, "/proc/%d/cmdline", pid) == -1)
		errExit("asprintf");
	int killdone = 0;

	while (monsec) {
		FILE *fp = fopen(monfile, "r");
		if (!fp) {
			killdone = 1;
			break;
		}

		char c;
		size_t count = fread(&c, 1, 1, fp);
		fclose(fp);
		if (count == 0) {
			// all done
			killdone = 1;
			break;
		}

		sleep(1);
		monsec--;
	}
	free(monfile);


	// force SIGKILL
	if (!killdone) {
		// kill the process and also the parent
		printf("Sending SIGKILL to %u\n", pid);
		kill(pid, SIGKILL);
		if (parent != pid) {
			printf("Sending SIGKILL to %u\n", parent);
			kill(parent, SIGKILL);
		}
	}

	clear_run_files(parent);
}
