tests/zfs-tests/cmd/readmmap.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 https://opensource.org/licenses/CDDL-1.0.
  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  * --------------------------------------------------------------
  29  *      BugId 5047993 : Getting bad read data.
  30  *
  31  *      Usage: readmmap <filename>
  32  *
  33  *      where:
  34  *              filename is an absolute path to the file name.
  35  *
  36  *      Return values:
  37  *              1 : error
  38  *              0 : no errors
  39  * --------------------------------------------------------------
  40  */
  41 #include <stdio.h>
  42 #include <stdlib.h>
  43 #include <unistd.h>
  44 #include <fcntl.h>
  45 #include <errno.h>
  46 #include <sys/mman.h>
  47 #include <sys/types.h>
  48 #include <time.h>
  49
  50 int
  51 main(int argc, char **argv)
  52 {
  53         const char *filename = "badfile";
  54         size_t size = 4395;
  55         size_t idx = 0;
  56         char *buf = NULL;
  57         char *map = NULL;
  58         int fd = -1, bytes, retval = 0;
  59         uint_t seed;
  60
  61         if (argc < 2 || optind == argc) {
  62                 (void) fprintf(stderr,
  63                     "usage: %s <file name>\n", argv[0]);
  64                 exit(1);
  65         }
  66
  67         if ((buf = calloc(1, size)) == NULL) {
  68                 perror("calloc");
  69                 exit(1);
  70         }
  71
  72         filename = argv[optind];
  73
  74         (void) remove(filename);
  75
  76         fd = open(filename, O_RDWR|O_CREAT|O_TRUNC, 0666);
  77         if (fd == -1) {
  78                 perror("open to create");
  79                 retval = 1;
  80                 goto end;
  81         }
  82
  83         bytes = write(fd, buf, size);
  84         if (bytes != size) {
  85                 (void) printf("short write: %d != %zd\n", bytes, size);
  86                 retval = 1;
  87                 goto end;
  88         }
  89
  90         map = mmap(0, size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
  91         if (map == MAP_FAILED) {
  92                 perror("mmap");
  93                 retval = 1;
  94                 goto end;
  95         }
  96         seed = (uint_t)time(NULL);
  97         srandom(seed);
  98
  99         idx = random() % size;
 100         map[idx] = 1;
 101
 102         if (msync(map, size, MS_SYNC) != 0) {
 103                 perror("msync");
 104                 retval = 1;
 105                 goto end;
 106         }
 107
 108         if (munmap(map, size) != 0) {
 109                 perror("munmap");
 110                 retval = 1;
 111                 goto end;
 112         }
 113
 114         bytes = pread(fd, buf, size, 0);
 115         if (bytes != size) {
 116                 (void) printf("short read: %d != %zd\n", bytes, size);
 117                 retval = 1;
 118                 goto end;
 119         }
 120
 121         if (buf[idx] != 1) {
 122                 (void) printf(
 123                     "bad data from read!  got buf[%zd]=%d, expected 1\n",
 124                     idx, buf[idx]);
 125                 retval = 1;
 126                 goto end;
 127         }
 128
 129         (void) printf("good data from read: buf[%zd]=1\n", idx);
 130 end:
 131         if (fd != -1) {
 132                 (void) close(fd);
 133         }
 134         if (buf != NULL) {
 135                 free(buf);
 136         }
 137
 138         return (retval);
 139 }