linux读取硬盘指定扇区

1 /* by hugang at 6/8 9:40 */
2 /* mod by jevan at 31/8 11:56 */
3 /* read some disk a sector */
4 #include <stdio.h>
5 #include <errno.h>
6 #include <unistd.h>
7 #include <sys/types.h>
8 #include <sys/stat.h>
9 #include <fcntl.h>
10
11 #include <linux/fs.h>
12
13 int
14 get_disk_sector (int fd)
15 {
16   int sectorsize;
17
18   ioctl (fd, BLKSSZGET, §orsize);
19
20   return sectorsize;
21 }
22
23 /**
24 * read_disk_sector:
25 * @dev: raw disk FILE *
26 * @sector:
27 * return is the disk sectorsize
28 * */
29 extern int errno;
30 int
31 read_disk_sector (int fd, unsigned long sector, char **p)
32 {
33   int sectorsize;
34   FILE *fp;
35
36 /* get disk sector size */
37   sectorsize = get_disk_sector (fd);
38   if (sectorsize == 0)
39     {
40       fprintf (stderr, "get disk sector size failed\n");
41       return (-1);
42     }
43
44 /* seek it */
45   lseek (fd, 0, SEEK_SET);
46   if (lseek (fd, (sectorsize * sector), SEEK_CUR) == -1)
47     {
48       fprintf (stderr, "seek to %d failed\n", sectorsize * sector);
49       return (-1);
50     }
51 /* read it */
52   *p = (char *) malloc (sectorsize);
53   if (*p == NULL)
54     {
55       fprintf (stderr, "malloc memory failed\n");
56       return (-1);
57     }
58
59   return read (fd, *p, sectorsize);
60 }
61
62 /* dump data for display */
63 void
64 dump_disk_sector (char *p, int size)
65 {
66   int i;
67   for (i = 0; i < size; i++)
68     {
69       if (i % 16 == 0 && i != 0)
70     printf ("\n");
71       printf ("%2x ",/* (unsigned int) p & 0xff*/(unsigned char)*p++);
72     }
73
74   printf ("\n");
75   return;
76 }
77
78 int
79 main (int argc,char* argv[])
80 {
81   char *d;
82   int size;
83   int fd;
84   char *dev = "/dev/sda";
85
86 /* open it */
87   fd = open (dev, O_RDONLY);
88   if (fd == -1)
89     {
90       fprintf (stderr, "open %s failed %s\n", dev, strerror (errno));
91       return (-1);
92     }
93
94   size = read_disk_sector (fd, atoi(argv[1]), &d);
95
96   close (fd);
97
98   if (size <= 0)
99     return (0);
100
101   dump_disk_sector (d, size);
102
103   free (d);
104
105   return (0);
106 }