tests/zfs-tests/cmd/largest_file/largest_file.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 /*
  28  * Copyright (c) 2012 by Delphix. All rights reserved.
  29  */
  30
  31 #include "../file_common.h"
  32 #include <sys/param.h>
  33 #include <signal.h>
  34 #include <stdio.h>
  35 #include <string.h>
  36 #include <sys/types.h>
  37 #include <unistd.h>
  38
  39 typedef long long       offset_t;
  40 #define MAXOFFSET_T     LLONG_MAX
  41
  42 /*
  43  * --------------------------------------------------------------
  44  *
  45  *      Assertion:
  46  *              The last byte of the largest file size can be
  47  *              accessed without any errors.  Also, the writing
  48  *              beyond the last byte of the largest file size
  49  *              will produce an errno of EFBIG.
  50  *
  51  * --------------------------------------------------------------
  52  *      If the write() system call below returns a "1",
  53  *      then the last byte can be accessed.
  54  * --------------------------------------------------------------
  55  */
  56 static void     sigxfsz(int);
  57 static void     usage(char *);
  58
  59 int
  60 main(int argc, char **argv)
  61 {
  62         int             fd = 0;
  63         offset_t        offset = (MAXOFFSET_T - 1);
  64         offset_t        llseek_ret = 0;
  65         int             write_ret = 0;
  66         int             err = 0;
  67         char            mybuf[5];
  68         char            *testfile;
  69         mode_t          mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH;
  70
  71         if (argc != 2) {
  72                 usage(argv[0]);
  73         }
  74
  75         (void) sigset(SIGXFSZ, sigxfsz);
  76
  77         testfile = strdup(argv[1]);
  78
  79         fd = open(testfile, O_CREAT | O_RDWR, mode);
  80         if (fd < 0) {
  81                 perror("Failed to create testfile");
  82                 err = errno;
  83                 goto out;
  84         }
  85
  86         llseek_ret = lseek64(fd, offset, SEEK_SET);
  87         if (llseek_ret < 0) {
  88                 perror("Failed to seek to end of testfile");
  89                 err = errno;
  90                 goto out;
  91         }
  92
  93         write_ret = write(fd, mybuf, 1);
  94         if (write_ret < 0) {
  95                 perror("Failed to write to end of file");
  96                 err = errno;
  97                 goto out;
  98         }
  99
 100         offset = 0;
 101         llseek_ret = lseek64(fd, offset, SEEK_CUR);
 102         if (llseek_ret < 0) {
 103                 perror("Failed to seek to end of file");
 104                 err = errno;
 105                 goto out;
 106         }
 107
 108         write_ret = write(fd, mybuf, 1);
 109         if (write_ret < 0) {
 110                 if (errno == EFBIG) {
 111                         (void) printf("write errno=EFBIG: success\n");
 112                         err = 0;
 113                 } else {
 114                         perror("Did not receive EFBIG");
 115                         err = errno;
 116                 }
 117         } else {
 118                 (void) printf("write completed successfully, test failed\n");
 119                 err = 1;
 120         }
 121
 122 out:
 123         (void) unlink(testfile);
 124         free(testfile);
 125         return (err);
 126 }
 127
 128 static void
 129 usage(char *name)
 130 {
 131         (void) printf("%s <testfile>\n", name);
 132         exit(1);
 133 }
 134
 135 /* ARGSUSED */
 136 static void
 137 sigxfsz(int signo)
 138 {
 139         (void) printf("\nlargest_file: sigxfsz() caught SIGXFSZ\n");
 140 }