testcases/kernel/syscalls/fork/fork08.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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

/*
 * NAME
 * 	fork08.c
 *
 * DESCRIPTION
 *	Check if the parent's file descriptors are affected by 
 * 	actions in the child; they should not be.
 *
 * ALGORITHM
 * 	Parent opens a file.
 * 	Forks a child which closes a file.
 * 	Parent forks a second child which attempts to read the (closed)
 * 	file.
 *
 * USAGE
 * 	fork08
 *
 * HISTORY
 *	07/2001 Ported by Wayne Boyer
 *
 * RESTRICTIONS
 * 	None
 */
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/stat.h>
#include <stdio.h>
#include "test.h"
#include "usctest.h"

char *TCID = "fork08";
int TST_TOTAL = 1;
extern int Tst_count;

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

char pbuf[10];
char fnamebuf[40];

int main(int ac, char **av)
{
	int status, count, forks, pid1;
	int ch_r_stat;
	FILE *rea, *writ;

	int lc;			/* loop counter */
	char *msg;		/* message returned from parse_opts */

	/*
	 * parse standard options
	 */
	if ((msg = parse_opts(ac, av, (option_t *)NULL, NULL)) != (char *)NULL){
		tst_brkm(TBROK, cleanup, "OPTION PARSING ERROR - %s", msg);
		/*NOTREACHED*/
	}

	/*
	 * perform global setup for the test
	 */
	setup();

	/*
	 * check 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;

		if ((writ = fopen(fnamebuf, "w")) == NULL)
			tst_resm(TFAIL, "failed to fopen file for write");
		if ((rea = fopen(fnamebuf, "r")) == NULL)
			tst_resm(TFAIL, "failed to fopen file for read");

		fprintf(writ,"abcdefghijklmnopqrstuv") ;
		fflush(writ);
		sleep(1);

		if ((getc(rea)) != 'a') 
			tst_resm(TFAIL, "getc from read side was confused");

		forks = 0;

forkone:
		++forks;

		if ((pid1 = fork()) != 0) {	/* parent */
			tst_resm(TINFO, "parent forksval: %d", forks);

			if ((pid1 != (-1)) && (forks < 2))
				goto forkone;
			else if (pid1 < 0) {
				tst_resm(TINFO, "Fork failed");
			} 
		} else {			/* child */
			/*
			 * If first child close the file descriptor for the
			 * read stream
			 */
			if (forks == 1) {
				if ((fclose(rea)) == -1) {
					tst_resm(TFAIL, "error in first child"
						 " closing fildes");
				}
				_exit(0);
			}

			/*
			 * If second child attempt to read from the file
			 */
			else if (forks == 2) {
				ch_r_stat = getc(rea);
				tst_resm(TINFO, "second child got char: %c",
					 ch_r_stat);
				if (ch_r_stat == 'b') {
					tst_resm(TPASS, "Test passed in child"
						 "number %d", forks);
					exit(0);
				}
				else if (ch_r_stat == EOF) {
					tst_resm(TFAIL, "Second child got "
						 "EOF");
					exit(-1);
				} else {
					tst_resm(TFAIL, "test failed in child"
						 "no %d", forks);
					exit(-1);
				}
			} else {		/* end of second child */
				tst_resm(TINFO, "forksnumber: %d", forks);
				exit(3);
			}
		}

		for (count = 0; count <= forks; count++) {
			wait(&status);
			tst_resm(TINFO, "exit status of wait "
				 " expected 0 got %d", status);
			status >>= 8;
			if (status == 0) {
				tst_resm(TPASS, "parent test PASSED");
			} else {
				tst_resm(TFAIL, "parent test FAILED");
			}
		}

		tst_resm(TINFO, "Number of processes forked is %d", forks);
		fclose(rea);
		fclose(writ);
	}
	cleanup();

	/*NOTREACHED*/
	return 0;
}
	
/*
 * setup() - performs all ONE TIME setup for this test
 */
void
setup()
{
	/*
	 * capture signals
	 */
	tst_sig(FORK, DEF_HANDLER, cleanup);

	umask(0);

	/*
	 * Pause if that option was specified
	 */
	TEST_PAUSE;

	/*
	 * make a temp directory and cd to it
	 */
	tst_tmpdir();
	
	strcpy(fnamebuf, "fork07.");
	sprintf(pbuf, "%d", getpid());
	strcat(fnamebuf, pbuf);
}

/*
 * cleanup() -	performs all ONE TIME cleanup for this test at
 * 	        completion or premature exit
 */
void
cleanup()
{
	/*
	 * print timing stats if that option was specified.
	 * print errno log if that option was specified.
	 */
	TEST_CLEANUP;

	/*
	 * remove tmp dir and all files in it
	 */
	tst_rmdir();

	tst_exit();
}