src/devzero.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (c) 2000-2003 Silicon Graphics, Inc.
   4  * All Rights Reserved.
   5  */
   6
   7 #include "global.h"
   8
   9 int
  10 main(int argc, char **argv)
  11 {
  12         off_t           offset = 0;
  13         int             blksize = 4096;
  14         long long       maxblks = -1;   /* no limit */
  15         long long       nblks = 0;
  16         int             value = 0;
  17         int             sts = 0;
  18         int             fd;
  19         char            *z;
  20         char            *path;
  21         int             oflags = O_WRONLY;
  22
  23         char    *progname;
  24
  25         if (strrchr(argv[0],'/'))
  26                 progname = strrchr(argv[0],'/')+1;
  27         else
  28                 progname = argv[0];
  29
  30         while ((fd = getopt(argc, argv, "b:n:o:v:ct")) != EOF) {
  31                 switch (fd) {
  32                 case 'b':
  33                         blksize = atoi(optarg) * 512;
  34                         break;
  35                 case 'n':
  36                         maxblks = atoll(optarg);
  37                         break;
  38                 case 'o':
  39                         offset = atoll(optarg);
  40                         break;
  41                 case 'v':
  42                         value = atoi(optarg);
  43                         break;
  44                 case 'c':
  45                         oflags |= O_CREAT;
  46                         break;
  47                 case 't':
  48                         oflags |= O_TRUNC;
  49                         break;
  50                 default:
  51                         sts++;
  52                 }
  53         }
  54         if (sts || argc - optind != 1) {
  55                 fprintf(stderr,
  56                         "Usage: %s [-b N*512] [-n N] [-o off] [-v val] "
  57                                 " [-c] [-t] <dev/file>\n",
  58                         progname);
  59                 fprintf(stderr,"      -c: create -t: truncate\n");
  60                 exit(1);
  61         }
  62
  63         path = argv[optind];
  64
  65         if ((fd = open(path, oflags, 0600)) < 0) {
  66                 fprintf(stderr,
  67                         "error opening \"%s\": %s\n",
  68                         path, strerror(errno));
  69                 exit(1);
  70         }
  71         if ((lseek64(fd, offset, SEEK_SET)) < 0) {
  72                 fprintf(stderr, "%s: error seeking to offset %llu "
  73                                         "on \"%s\": %s\n",
  74                         progname, (unsigned long long)offset, path, strerror(errno));
  75                 exit(1);
  76         }
  77
  78         if ((z = memalign(getpagesize(), blksize)) == NULL) {
  79                 fprintf(stderr, "%s: can't memalign %u bytes: %s\n",
  80                         progname, blksize, strerror(errno));
  81                 exit(1);
  82         }
  83         memset(z, value, blksize);
  84         errno = 0;
  85         for (;;) {
  86                 if (nblks++ == maxblks)
  87                         break;
  88                 if ((sts = write(fd, z, blksize)) < blksize) {
  89                         if (errno == ENOSPC || sts >= 0)
  90                                 break;
  91                         fprintf(stderr, "%s: write failed: %s\n",
  92                                 progname, strerror(errno));
  93                         break;
  94                 }
  95         }
  96         printf("Wrote %.2fKb (value 0x%x)\n",
  97                 (double) ((--nblks) * blksize) / 1024, value);
  98         free(z);
  99         return 0;
 100 }