testcases/kernel/syscalls/waitpid/waitpid09.c

/*
 *
 *   Copyright (c) International Business Machines  Corp., 2001
 *
 *   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
 */

/*
 * NAME
 *	waitpid09.c
 *
 * DESCRIPTION
 *	Check ability of parent to wait until child returns, and that the
 *	child's process id is returned through the waitpid. Check that
 *	waitpid returns immediately if no child is present.
 *
 * ALGORITHM
 *	case 0:
 *		Parent forks a child and waits. Parent should do nothing
 *		further until child returns. The pid of the forked child
 *		should match the returned value from the waitpid.
 *
 *	case 1:
 *		Parent calls a waitpid with no children waiting. Waitpid
 *		should return a -1 since there are no children to wait for.
 *
 * USAGE:  <for command-line>
 *      waitpid09 [-c n] [-e] [-i n] [-I x] [-P x] [-t]
 *      where,  -c n : Run n copies concurrently.
 *              -e   : Turn on errno logging.
 *              -i n : Execute test n times.
 *              -I x : Execute test for x seconds.
 *              -P x : Pause for x seconds between iterations.
 *              -t   : Turn on syscall timing.
 *
 * History
 *	07/2001 John George
 *		-Ported
 *      04/2002 wjhuie sigset cleanups
 *
 * Restrictions
 *	None
 */

#define _GNU_SOURCE 1
#include <sys/types.h>
#include <signal.h>
#include <errno.h>
#include <sys/wait.h>
#include <stdlib.h>

#include "test.h"

char *TCID = "waitpid09";
int TST_TOTAL = 1;
volatile int intintr;

static void setup(void);
static void cleanup(void);
static void inthandlr();
static void do_exit(void);
static void setup_sigint(void);
#ifdef UCLINUX
static void do_exit_uclinux(void);
#endif

int main(int argc, char **argv)
{
	int lc;
	const char *msg;

	int fail, pid, status, ret;

	msg = parse_opts(argc, argv, NULL, NULL);
	if (msg != NULL)
		tst_brkm(TBROK, NULL, "OPTION PARSING ERROR - %s", msg);

#ifdef UCLINUX
	maybe_run_child(&do_exit_uclinux, "");
#endif

	setup();

	pid = FORK_OR_VFORK();
	if (pid < 0) {
		tst_brkm(TFAIL, cleanup, "Fork Failed");
	} else if (pid == 0) {
		/*
		 * Child:
		 * Set up to catch SIGINT.  The kids will wait till a
		 * SIGINT has been received before they proceed.
		 */
		setup_sigint();

		/* check for looping state if -i option is given */
		for (lc = 0; TEST_LOOPING(lc); lc++) {
			/* reset tst_count in case we are looping */
			tst_count = 0;

			intintr = 0;

			fail = 0;
			pid = FORK_OR_VFORK();
			if (pid < 0) {
				tst_brkm(TFAIL, cleanup, "Fork failed.");
			} else if (pid == 0) {	/* child */
#ifdef UCLINUX
				if (self_exec(argv[0], "") < 0) {
					tst_brkm(TFAIL, cleanup,
						 "self_exec failed");
				}
#else
				do_exit();
#endif
			} else {	/* parent */

				/*
				 *Check that waitpid with WNOHANG returns zero
				 */
				while (((ret = waitpid(pid, &status, WNOHANG))
					!= 0) || (errno == EINTR)) {
					if (ret == -1)
						continue;

					tst_resm(TFAIL, "return value for "
						 "WNOHANG expected 0 got %d",
						 ret);
					fail = 1;
				}
#ifdef UCLINUX
				/* Give the kids a chance to setup SIGINT again, since
				 * this is cleared by exec().
				 */
				sleep(3);
#endif

				/* send SIGINT to child to tell it to proceed */
				if (kill(pid, SIGINT) < 0) {
					tst_resm(TFAIL, "Kill of child failed, "
						 "errno = %d", errno);
					fail = 1;
				}

				while (((ret = waitpid(pid, &status, 0)) != -1)
				       || (errno == EINTR)) {
					if (ret == -1)
						continue;

					if (ret != pid) {
						tst_resm(TFAIL, "Expected %d "
							 "got %d as proc id of "
							 "child", pid, ret);
						fail = 1;
					}

					if (status != 0) {
						tst_resm(TFAIL, "status value "
							 "got %d expected 0",
							 status);
						fail = 1;
					}
				}
			}

			pid = FORK_OR_VFORK();
			if (pid < 0) {
				tst_brkm(TFAIL, cleanup, "Second fork failed.");
			} else if (pid == 0) {	/* child */
				exit(0);
			} else {	/* parent */
				/* Give the child time to startup and exit */
				sleep(2);

				while (((ret = waitpid(pid, &status, WNOHANG))
					!= -1) || (errno == EINTR)) {
					if (ret == -1)
						continue;

					if (ret != pid) {
						tst_resm(TFAIL, "proc id %d "
							 "and retval %d do not "
							 "match", pid, ret);
						fail = 1;
					}

					if (status != 0) {
						tst_resm(TFAIL, "non zero "
							 "status received %d",
							 status);
						fail = 1;
					}
				}
			}

			if (fail)
				tst_resm(TFAIL, "case 1 FAILED");
			else
				tst_resm(TPASS, "case 1 PASSED");

			fail = 0;
			ret = waitpid(pid, &status, 0);

			if (ret != -1) {
				tst_resm(TFAIL, "Expected -1 got %d", ret);
				fail = 1;
			}
			if (errno != ECHILD) {
				tst_resm(TFAIL, "Expected ECHILD got %d",
					 errno);
				fail = 1;
			}

			ret = waitpid(pid, &status, WNOHANG);
			if (ret != -1) {
				tst_resm(TFAIL, "WNOHANG: Expected -1 got %d",
					 ret);
				fail = 1;
			}
			if (errno != ECHILD) {
				tst_resm(TFAIL, "WNOHANG: Expected ECHILD got "
					 "%d", errno);
				fail = 1;
			}

			if (fail)
				tst_resm(TFAIL, "case 2 FAILED");
			else
				tst_resm(TPASS, "case 2 PASSED");
		}

		cleanup();
	} else {
		/* wait for the child to return */
		waitpid(pid, &status, 0);
		if (WEXITSTATUS(status) != 0) {
			tst_brkm(TBROK, cleanup, "child returned bad "
				 "status");
		}
	}

	tst_exit();
}

/*
 * setup_sigint()
 *	sets up a SIGINT handler
 */
static void setup_sigint(void)
{
	if ((sig_t) signal(SIGINT, inthandlr) == SIG_ERR) {
		tst_brkm(TFAIL, cleanup, "signal SIGINT failed, errno = %d",
			 errno);
	}
}

static void setup(void)
{
	TEST_PAUSE;
}

static void cleanup(void)
{
}

static void inthandlr(void)
{
	intintr++;
}

static void wait_for_parent(void)
{
	int testvar;
	while (!intintr)
		testvar = 0;
}

static void do_exit(void)
{
	wait_for_parent();
	exit(0);
}

#ifdef UCLINUX
/*
 * do_exit_uclinux()
 *	Sets up SIGINT handler again, then calls do_exit
 */
static void do_exit_uclinux(void)
{
	setup_sigint();
	do_exit();
}
#endif