lib/libdisk/blocks.c

   1 /*
   2  * ----------------------------------------------------------------------------
   3  * "THE BEER-WARE LICENSE" (Revision 42):
   4  * <phk@FreeBSD.org> wrote this file.  As long as you retain this notice you
   5  * can do whatever you want with this stuff. If we meet some day, and you think
   6  * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
   7  * ----------------------------------------------------------------------------
   8  */
   9
  10 #include <sys/cdefs.h>
  11 __FBSDID("$FreeBSD$");
  12
  13 #include <stdio.h>
  14 #include <stdlib.h>
  15 #include <unistd.h>
  16 #include "libdisk.h"
  17
  18 void *
  19 read_block(int fd, daddr_t block, u_long sector_size)
  20 {
  21         void *foo;
  22         int i;
  23
  24         foo = malloc(sector_size);
  25         if (foo == NULL)
  26                 return (NULL);
  27         if (-1 == lseek(fd, (off_t)block * sector_size, SEEK_SET)) {
  28                 free (foo);
  29                 return (NULL);
  30         }
  31         i = read(fd, foo, sector_size);
  32         if ((int)sector_size != i) {
  33                 free (foo);
  34                 return (NULL);
  35         }
  36         return foo;
  37 }
  38
  39 int
  40 write_block(int fd, daddr_t block, const void *foo, u_long sector_size)
  41 {
  42         int i;
  43
  44         if (-1 == lseek(fd, (off_t)block * sector_size, SEEK_SET))
  45                 return (-1);
  46         i = write(fd, foo, sector_size);
  47         if ((int)sector_size != i)
  48                 return (-1);
  49         return 0;
  50 }