1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
|
/* Taken from util-linux source. GPLv2.
* Emits the current rootfs device.
* Works by searching /dev recursively for a BLK device with the same device
* number as '/'.
*/
#include <stdio.h>
#include <err.h>
#include <sys/types.h>
#include <dirent.h>
#include <sys/stat.h>
#include <string.h>
static int
find_dev_recursive(char *dirnamebuf, int number, int deviceOnly) {
DIR *dp;
struct dirent *dir;
struct stat s;
int dirnamelen = 0;
if ((dp = opendir(dirnamebuf)) == NULL)
err(1, "can't read directory %s", dirnamebuf);
dirnamelen = strlen(dirnamebuf);
while ((dir = readdir(dp)) != NULL) {
if (!strcmp(dir->d_name, ".") || !strcmp(dir->d_name, ".."))
continue;
if (dirnamelen + 1 + strlen(dir->d_name) > PATH_MAX)
continue;
dirnamebuf[dirnamelen] = '/';
strcpy(dirnamebuf+dirnamelen+1, dir->d_name);
if (lstat(dirnamebuf, &s) < 0)
continue;
if ((s.st_mode & S_IFMT) == S_IFBLK && s.st_rdev == number){
if (deviceOnly) {
int len = strlen(dirnamebuf);
char c = 0;
do {
c = dirnamebuf[len-1];
--len;
}while(c > 0 && c < 9 && len > 0);
/* arm has "p" for partition */
if (dirnamebuf[len-1] == 'p')
--len;
dirnamebuf[len]='\0';
}
return 1;
}
if ((s.st_mode & S_IFMT) == S_IFDIR &&
find_dev_recursive(dirnamebuf, number, deviceOnly))
return 1;
}
dirnamebuf[dirnamelen] = 0;
closedir(dp);
return 0;
}
void usage(){
printf ("rootdev \n\t-d (for device only)\n");
}
int main(int argc, char *argv[]) {
struct stat s;
char *file = "/";
static char name[PATH_MAX+1];
int deviceOnly=0;
int c;
extern char *optarg;
extern int optind, optopt;
while ((c = getopt(argc, argv, "hd")) != -1) {
switch(c) {
case 'd':
deviceOnly=1;
break;
case 'h':
default:
usage();
return 1;
}
}
if (argc - optind >= 1)
file = argv[optind];
if (stat(file, &s) < 0)
err(1, "unable to stat %s", file);
if (!s.st_dev)
err(1, "unknown device number 0");
strcpy(name, "/dev");
if (!find_dev_recursive(name, s.st_dev, deviceOnly)) {
fprintf(stderr, "unable to find match\n");
return 1;
}
printf("%s\n", name);
return 0;
}
|
