#define _XOPEN_SOURCE 600

#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <fcntl.h>
#include <string.h>
#include <errno.h>

int main(void)
{
	char tmpfname[256];
	long page_size;
	long total_size;

	void *pa;
	size_t len;
	int i, fd;
	
	pid_t child;
	char *ch;
	int exit_val;

	page_size = sysconf(_SC_PAGE_SIZE);

	/* Size of the file to be mapped */
	total_size = page_size / 2;

	/* mmap will create a partial page */
	len = page_size / 2;

	snprintf(tmpfname, sizeof(tmpfname), "/tmp/pts_mmap_11_5_%d", getpid());
	
	/* Create shared file */
	unlink(tmpfname);
	fd = open(tmpfname, O_CREAT | O_RDWR | O_EXCL, S_IRUSR | S_IWUSR);
	if (fd == -1) {
		printf("Error at open(): %s\n", strerror(errno));
		return 1;
	}
	if (ftruncate(fd, total_size) == -1) {
		printf("Error at ftruncate(): %s\n", strerror(errno));
		return 1;
	}

	pa = mmap(NULL, len, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
	if (pa == MAP_FAILED) {
		printf("Error at mmap(): %s\n", strerror(errno));
		return 1;
	}
		
	ch = (char*)pa + len + 1;

	/* Check the patial page is ZERO filled */
	for (i = 0; i < page_size/2 - 1; i++) {
		if (ch[i] != 0) {
			printf("Test FAILED: The partial page at the "
			       "end of the file is not zero-filled\n");
			return 1;
		}
	}

	/* Write to the partial page */
	*ch = 'b';
	//msync(pa, len, MS_SYNC);
	munmap(pa, len);
	close(fd);

	/* Open and map it again */
	fd = open(tmpfname, O_RDWR, 0);
	unlink(tmpfname);

	pa = mmap(NULL, len, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
	if (pa == MAP_FAILED) {
		printf("Error at 2nd mmap(): %s\n", strerror(errno));
		return 1;
	}

	ch = pa + len + 1;
	if (*ch == 'b') {
		printf("Test FAILED: Modification of the partial page "
		       "at the end of an object is written out\n");
		return 1;
	}
	
	close(fd);
	munmap(pa, len);

	printf("Test PASSED\n");
	return 1;
}