root/tests/sys/cddl/zfs/bin/largest_file.c
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */


#include "file_common.h"
#include <sys/param.h>
#include <signal.h>
#include <stdio.h>

/*
 * --------------------------------------------------------------
 *
 *      Assertion:
 *              The last byte of the largest file size can be
 *              accessed without any errors.  Also, the writing
 *              beyond the last byte of the largest file size
 *              will produce an errno of EFBIG.
 *
 * --------------------------------------------------------------
 *      If the write() system call below returns a "1",
 *      then the last byte can be accessed.
 * --------------------------------------------------------------
 */
static void     sigxfsz(int);
static void     usage(char *);

int
main(int argc, char **argv)
{
        int             fd = 0;
        off_t           offset = (OFF_MAX - 1);
        off_t           lseek_ret = 0;
        int             write_ret = 0;
        int             err = 0;
        char            mybuf[5];
        char            *testfile;

        if (argc != 2) {
                usage(argv[0]);
        }

        (void) sigset(SIGXFSZ, sigxfsz);

        testfile = strdup(argv[1]);

        fd = open(testfile, O_CREAT | O_RDWR);
        if (fd < 0) {
                perror("Failed to create testfile");
                err = errno;
                goto out;
        }

        lseek_ret = lseek(fd, offset, SEEK_SET);
        if (lseek_ret < 0) {
                perror("Failed to seek to end of testfile");
                err = errno;
                goto out;
        }

        write_ret = write(fd, mybuf, 1);
        if (write_ret < 0) {
                perror("Failed to write to end of file");
                err = errno;
                goto out;
        }

        offset = 0;
        lseek_ret = lseek(fd, offset, SEEK_CUR);
        if (lseek_ret < 0) {
                perror("Failed to seek to end of file");
                err = errno;
                goto out;
        }

        write_ret = write(fd, mybuf, 1);
        if (write_ret < 0) {
                if (errno == EFBIG) {
                        (void) printf("write errno=EFBIG: success\n");
                        err = 0;
                } else {
                        perror("Did not receive EFBIG");
                        err = errno;
                }
        } else {
                (void) printf("write completed successfully, test failed\n");
                err = 1;
        }

out:
        (void) unlink(testfile);
        free(testfile);
        return (err);
}

static void
usage(char *name)
{
        (void) printf("%s <testfile>\n", name);
        exit(1);
}

/* ARGSUSED */
static void
sigxfsz(int signo)
{
        (void) printf("\nlargest_file: sigxfsz() caught SIGXFSZ\n");
}