testcases/open_posix_testsuite/conformance/interfaces/pthread_rwlockattr_getpshared/2-1.c

/*
 * Copyright (c) 2002, Intel Corporation. All rights reserved.
 * This file is licensed under the GPL license.  For the full content
 * of this license, see the COPYING file at the top level of this
 * source tree.
 *
 *	The process-shared attribute shall be set to PTHREAD_PROCESS_SHARED
 *	to permit a read-write lock to be operated upon by any thread
 *	that has access to the memory where the read-write lock is allocated,
 *	even if the read-write lock is allocated in memory that is shared by
 *	multiple processes.
 *
 * steps:
 *	1. Create a piece of shared memory object, create a read write lock 'rwlock' and
 *	   set the PTHREAD_PROCESS_SHARED attribute.
 *	2. Parent map the shared memory to its memory space, put 'rwlock' into it;
 *	3. Parent get read lock;
 *	4. Fork to create child, parent wait until child call pthread_rwlock_wrlock()
 *	5. Child map the shared memory to its memory space;
 *	6. Child call pthread_rwlock_trywrlock(), should fail with EBUSY;
 *	7. Child call pthread_rwlock_wrlock(), should block;
 *	8. Parent unlock 'rwlock'
 *	9. Child should get the write lock.
 */

#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <errno.h>
#include <fcntl.h>
#include <pthread.h>
#include <stdio.h>
#include <unistd.h>
#include "posixtest.h"

struct shmstruct {
	pthread_rwlock_t rwl;
	int data;
} *rwlock_data;

int main(void)
{

	/* Make sure there is process-shared capability. */
#ifndef PTHREAD_PROCESS_SHARED
	fprintf(stderr,
		"process-shared attribute is not available for testing\n");
	return PTS_UNSUPPORTED;
#endif

	pthread_rwlockattr_t rwla;
	int pshared = PTHREAD_PROCESS_SHARED;

	char shm_name[] = "tmp_pthread_rwlock_getpshared";
	int shm_fd;
	int pid;

	/* Initialize a rwlock attributes object */
	if (pthread_rwlockattr_init(&rwla) != 0) {
		printf("Error at pthread_rwlockattr_init()\n");
		return PTS_UNRESOLVED;
	}

	if (pthread_rwlockattr_setpshared(&rwla, pshared) != 0) {
		printf("Error at pthread_rwlockattr_setpshared()\n");
		return PTS_UNRESOLVED;
	}

	if (pthread_rwlockattr_getpshared(&rwla, &pshared) != 0) {
		printf
		    ("Test FAILED: Error at pthread_rwlockattr_getpshared()\n");
		return PTS_FAIL;
	}

	if (pshared != PTHREAD_PROCESS_SHARED) {
		printf("Test FAILED: Got error shared attribute value %d\n",
		       pshared);
		return PTS_FAIL;
	}

	/* Create shared object */
	shm_unlink(shm_name);
	shm_fd =
	    shm_open(shm_name, O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR);
	if (shm_fd == -1) {
		perror("Error at shm_open()");
		return PTS_UNRESOLVED;
	}

	if (ftruncate(shm_fd, sizeof(struct shmstruct)) != 0) {
		perror("Error at ftruncate()");
		shm_unlink(shm_name);
		return PTS_UNRESOLVED;
	}

	/* Map the shared memory object to my memory */
	rwlock_data =
	    mmap(NULL, sizeof(struct shmstruct), PROT_READ | PROT_WRITE,
		 MAP_SHARED, shm_fd, 0);

	if (rwlock_data == MAP_FAILED) {
		perror("Error at first mmap()");
		shm_unlink(shm_name);
		return PTS_UNRESOLVED;
	}

	if ((pthread_rwlock_init(&(rwlock_data->rwl), &rwla)) != 0) {
		printf("Error at pthread_rwlock_init()\n");
		return PTS_UNRESOLVED;
	}

	if ((pthread_rwlockattr_destroy(&rwla)) != 0) {
		printf("Error at pthread_rwlockattr_destroy()\n");
		return PTS_UNRESOLVED;
	}

	printf("Parent getting read lock.\n");
	if ((pthread_rwlock_rdlock(&(rwlock_data->rwl))) != 0) {
		printf("Error at pthread_rwlock_rdlock()\n");
		return PTS_UNRESOLVED;
	}
	printf("Parent got read lock.\n");
	rwlock_data->data = 0;

	pid = fork();
	if (pid == -1) {
		perror("Error at fork()");
		return PTS_UNRESOLVED;
	} else if (pid > 0) {
		/* Parent */
		/* wait until child do wrlock */
		while (rwlock_data->data == 0) {
			sleep(1);
		}

		printf("Parent unlocking.\n");
		if (pthread_rwlock_unlock(&(rwlock_data->rwl)) != 0) {
			printf("Parent: error at pthread_rwlock_unlock()\n");
			return PTS_FAIL;
		}
		printf("Parent unlocked.\n");

		/* Wait for child to end */
		wait(NULL);

		if ((shm_unlink(shm_name)) != 0) {
			perror("Error at shm_unlink()");
			return PTS_UNRESOLVED;
		}

		if (rwlock_data->data == -1) {
			printf
			    ("Test FAILED: child did not block on write lock\n");
			return PTS_FAIL;
		}

		printf("Test PASSED\n");
		return PTS_PASS;
	} else {
		/* Child */
		/* Map the shared object to child's memory */
		rwlock_data =
		    mmap(NULL, sizeof(struct shmstruct), PROT_READ | PROT_WRITE,
			 MAP_SHARED, shm_fd, 0);

		if (rwlock_data == MAP_FAILED) {
			perror("Error at first mmap()");
			return PTS_UNRESOLVED;
		}

		printf("Child tries to get write lock, should get EBUSY.\n");
		if ((pthread_rwlock_trywrlock(&(rwlock_data->rwl))) != EBUSY) {
			printf("Test FAILED: Child expects EBUSY\n");
			return PTS_FAIL;
		}
		printf("Child got EBUSY.\n");

		printf("Child do wrlock.\n");

		/* Tell parent it can unlock now */
		rwlock_data->data = 1;

		/* Should block until parent unlock */
		if ((pthread_rwlock_wrlock(&(rwlock_data->rwl))) != 0) {
			printf("Child:pthread_rwlock_wrlock() error\n");
			printf
			    ("Test FAILED: Error while write lock the shared rwlock\n");
			rwlock_data->data = -1;
			return PTS_FAIL;
		}
		printf("Child got wrlock.\n");
		if ((pthread_rwlock_unlock(&(rwlock_data->rwl))) != 0) {
			printf("Child:pthread_rwlock_unlock() error\n");
			printf("Error while write unlock the shared rwlock\n");
			rwlock_data->data = -1;
			return PTS_FAIL;
		}
	}
}