root/usr/src/test/zfs-tests/tests/functional/libzfs/many_fds.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 (C) 2015 STRATO AG.
 */
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <libzfs.h>
#include <sys/resource.h>
#include <errno.h>

/*
 * Check if libzfs works with more than 255 held file handles.
 */
/* ARGSUSED */
int
main(int argc, char **argv)
{
        int i;
        struct rlimit limit;
        libzfs_handle_t *h;

        limit.rlim_cur = 65535;
        limit.rlim_max = 65535;

        if (setrlimit(RLIMIT_NOFILE, &limit) != 0) {
                (void) printf("many_fds: setrlimit() failed with errno=%d\n",
                    errno);
                exit(1);
        }

        for (i = 0; i < 255; ++i) {
                int fd = open("/dev/null", O_RDONLY);
                if (fd == -1) {
                        (void) printf("open failed with errno=%d\n", errno);
                        return (1);
                }
        }

        h = libzfs_init();

        if (h != NULL) {
                libzfs_fini(h);
                return (0);
        } else {
                (void) printf("many_fds: libzfs_init() failed with errno=%d\n",
                    errno);
                return (1);
        }
}