testcases/network/nfs/nfslock01/nfs_flock.c

/*
 * Program for testing file locking. The original data file consists of
 * characters from 'A' to 'Z'. The data file after running this program
 * would consist of lines with 1's in even lines and 0's in odd lines.
 */

#include "nfs_flock.h"
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#define BYTES 64
#define LINES 16384

int main(int argc, char **argv)
{
	int i, fd, mac;
	int offset = 0;
	char buf[BUFSIZ];

	if (argc != 3) {
		fprintf(stderr, "Usage: %s <mac num> <file name>\n", argv[0]);
		exit(2);
	}

	if ((fd = open(argv[2], O_RDWR)) < 0) {
		perror("opening a file");
		exit(1);
	}

	mac = atoi(argv[1]);

	/*
	 * Replace a line of characters by 1's if it is process one
	 * else with 0's. Number of charcters in any line are BYTES-1,
	 * the last character being a newline character.
	 */
	for (i = 0; i < BYTES - 1; i++) {
		if (mac == 1)
			buf[i] = '1';
		else
			buf[i] = '0';
	}
	buf[BYTES - 1] = '\n';

	for (i = 0; i < LINES; i++) {
		if (mac == 1) {	/* Set the offset to even lines */
			if ((i % 2) == 0) {
				if (i == 0)
					offset = 0;
				else
					offset += 2 * BYTES;
			} else
				continue;
		} else {	/* Set the offset to odd lines */
			if ((i % 2) == 1) {
				if (i == 1)
					offset = BYTES;
				else
					offset += 2 * BYTES;
			} else
				continue;
		}

		if (writeb_lock(fd, offset, SEEK_SET, BYTES) < 0)
			printf("failed in writeb_lock, Errno = %d", errno);

		lseek(fd, offset, SEEK_SET);

		/* write to the test file */
		write(fd, buf, BYTES);

		if (unb_lock(fd, offset, SEEK_SET, BYTES) < 0)
			printf("failed in unb_lock, Errno = %d", errno);
	}
	exit(0);
}