e2fsck/extend.c

   1 /*
   2  * extend.c --- extend a file so that it has at least a specified
   3  *      number of blocks.
   4  *
   5  * Copyright (C) 1993, 1994, 1995 Theodore Ts'o.
   6  *
   7  * This file may be redistributed under the terms of the GNU Public
   8  * License.
   9  */
  10
  11 #include "config.h"
  12 #include <stdio.h>
  13 #include <unistd.h>
  14 #include <stdlib.h>
  15 #include <string.h>
  16 #include <sys/types.h>
  17 #include <fcntl.h>
  18 #include "../misc/nls-enable.h"
  19
  20 static void usage(char *progname)
  21 {
  22         fprintf(stderr, _("%s: %s filename nblocks blocksize\n"),
  23                 progname, progname);
  24         exit(1);
  25 }
  26
  27
  28 int main(int argc, char **argv)
  29 {
  30         char    *filename;
  31         int     nblocks, blocksize;
  32         int     fd;
  33         char    *block;
  34         int     ret;
  35
  36         if (argc != 4)
  37                 usage(argv[0]);
  38
  39         filename = argv[1];
  40         nblocks = strtoul(argv[2], 0, 0) - 1;
  41         blocksize = strtoul(argv[3], 0, 0);
  42
  43         if (nblocks < 0) {
  44                 fprintf(stderr, _("Illegal number of blocks!\n"));
  45                 exit(1);
  46         }
  47
  48         block = malloc(blocksize);
  49         if (block == 0) {
  50                 fprintf(stderr, _("Couldn't allocate block buffer (size=%d)\n"),
  51                         blocksize);
  52                 exit(1);
  53         }
  54         memset(block, 0, blocksize);
  55
  56         fd = open(filename, O_RDWR);
  57         if (fd < 0) {
  58                 perror(filename);
  59                 exit(1);
  60         }
  61         ret = lseek(fd, nblocks*blocksize, SEEK_SET);
  62         if (ret < 0) {
  63                 perror("lseek");
  64                 exit(1);
  65         }
  66         ret = read(fd, block, blocksize);
  67         if (ret < 0) {
  68                 perror("read");
  69                 exit(1);
  70         }
  71         ret = lseek(fd, nblocks*blocksize, SEEK_SET);
  72         if (ret < 0) {
  73                 perror("lseek #2");
  74                 exit(1);
  75         }
  76         ret = write(fd, block, blocksize);
  77         if (ret < 0) {
  78                 perror("read");
  79                 exit(1);
  80         }
  81         exit(0);
  82 }