testcases/kernel/syscalls/pipe/pipe01.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
 *	pipe01.c
 *
 * DESCRIPTION
 *	Testcase to check the basic functionality of the pipe(2) syscall:
 *	Check that both ends of the pipe (both file descriptors) are
 *	available to a process opening the pipe.
 *
 * ALGORITHM
 *	Write a string of characters down a pipe; read the string from the
 *	other file descriptor. Test passes if both can be done, as reported
 *	by the number of characters written and read.
 *
 * USAGE:  <for command-line>
 *  pipe01 [-c n] [-f] [-i n] [-I x] [-P x] [-t]
 *     where,  -c n : Run n copies concurrently.
 *             -f   : Turn off functionality Testing.
 *             -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.
 *
 * RESTRICITONS
 *	NONE
 */
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include "test.h"

char *TCID = "pipe01";
int TST_TOTAL = 1;

void setup(void);
void cleanup(void);

ssize_t safe_read(int fd, void *buf, size_t count)
{
	ssize_t n;

	do {
		n = read(fd, buf, count);
	} while (n < 0 && errno == EINTR);

	return n;
}

int main(int ac, char **av)
{
	int lc;
	const char *msg;

	int fildes[2];		/* fds for pipe read and write */
	char wrbuf[BUFSIZ], rebuf[BUFSIZ];
	int red, written;	/* no. of chars read/written to pipe */
	int greater, length;

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

	setup();

	for (lc = 0; TEST_LOOPING(lc); lc++) {

		/* reset tst_count in case we are looping */
		tst_count = 0;

		TEST(pipe(fildes));

		if (TEST_RETURN == -1) {
			tst_resm(TFAIL, "pipe() failed unexpectedly - errno %d",
				 TEST_ERRNO);
			continue;
		}

		strcpy(wrbuf, "abcdefghijklmnopqrstuvwxyz");
		length = strlen(wrbuf);

		if ((written = write(fildes[1], wrbuf, length)) == -1) {
			tst_brkm(TBROK, cleanup, "write() failed");
		}

		if (written < 0 || written > 26) {
			tst_resm(TFAIL, "Condition #1 test failed");
			continue;
		}

		if ((red = safe_read(fildes[0], rebuf, written)) == -1) {
			tst_brkm(TBROK | TERRNO, cleanup,
				 "read() failed");
		}

		if (red < 0 || red > written) {
			tst_resm(TFAIL, "Condition #2 test failed");
			continue;
		}

		/* are the strings written and read equal */
		if ((greater = strncmp(rebuf, wrbuf, red)) != 0) {
			tst_resm(TFAIL, "Condition #3 test failed");
			continue;
		}
		tst_resm(TPASS, "pipe() functionality is correct");
	}

	cleanup();
	tst_exit();
}

/*
 * setup() - performs all ONE TIME setup for this test.
 */
void setup(void)
{

	tst_sig(NOFORK, DEF_HANDLER, cleanup);

	TEST_PAUSE;
}

/*
 * cleanup() - performs all ONE TIME cleanup for this test at
 *	       completion or premature exit.
 */
void cleanup(void)
{
}