Annotation of /tags/mkinitrd-6_2_2/nash/name_to_dev_t.c
Parent Directory | Revision Log
Revision 1001 -
(hide annotations)
(download)
Sun May 30 12:28:42 2010 UTC (14 years, 4 months ago) by niro
File MIME type: text/plain
File size: 3437 byte(s)
Sun May 30 12:28:42 2010 UTC (14 years, 4 months ago) by niro
File MIME type: text/plain
File size: 3437 byte(s)
tagged 'mkinitrd-6_2_2'
1 | niro | 532 | #include <stdlib.h> |
2 | #include <string.h> | ||
3 | #include <unistd.h> | ||
4 | #include <ctype.h> | ||
5 | #include <stdio.h> | ||
6 | #include <fcntl.h> | ||
7 | #include <sys/stat.h> | ||
8 | |||
9 | #include "name_to_dev_t.h" | ||
10 | |||
11 | static dev_t | ||
12 | try_name(char *name, int part) | ||
13 | { | ||
14 | char path[64]; | ||
15 | char buf[32]; | ||
16 | int range; | ||
17 | dev_t res; | ||
18 | char *s; | ||
19 | int len; | ||
20 | int fd; | ||
21 | unsigned int maj, min; | ||
22 | struct stat sb; | ||
23 | |||
24 | /* read device number from .../dev */ | ||
25 | |||
26 | sprintf(path, "/sys/block/%s/dev", name); | ||
27 | fd = open(path, O_RDONLY); | ||
28 | if (fd < 0) | ||
29 | goto fail; | ||
30 | len = read(fd, buf, 32); | ||
31 | close(fd); | ||
32 | if (len <= 0 || len == 32 || buf[len - 1] != '\n') | ||
33 | goto fail; | ||
34 | buf[len - 1] = '\0'; | ||
35 | if (sscanf(buf, "%u:%u", &maj, &min) != 2) | ||
36 | goto fail; | ||
37 | res = makedev(maj, min); | ||
38 | if (maj != major(res) || min != minor(res)) | ||
39 | goto fail; | ||
40 | |||
41 | /* if it's there and we are not looking for a partition - that's it */ | ||
42 | if (!part) | ||
43 | return res; | ||
44 | |||
45 | /* otherwise read range from .../range */ | ||
46 | snprintf(path, 64, "/sys/block/%s/range", name); | ||
47 | fd = open(path, O_RDONLY); | ||
48 | if (fd < 0) | ||
49 | goto fail; | ||
50 | len = read(fd, buf, 32); | ||
51 | close(fd); | ||
52 | if (len <= 0 || len == 32 || buf[len - 1] != '\n') | ||
53 | goto fail; | ||
54 | buf[len - 1] = '\0'; | ||
55 | range = strtoul(buf, &s, 10); | ||
56 | if (*s) | ||
57 | goto fail; | ||
58 | |||
59 | /* if partition is within range - we got it */ | ||
60 | if (part < range) | ||
61 | return res + part; | ||
62 | fail: | ||
63 | sprintf(path, "/dev/%s", name); | ||
64 | if (!stat(path, &sb)) { | ||
65 | if (S_ISBLK(sb.st_mode)) | ||
66 | return sb.st_rdev; | ||
67 | } | ||
68 | return 0; | ||
69 | } | ||
70 | |||
71 | /* | ||
72 | * Convert a name into device number. We accept the following variants: | ||
73 | * | ||
74 | * 1) device number in hexadecimal represents itself | ||
75 | * 2) /dev/nfs represents Root_NFS (0xff) | ||
76 | * 3) /dev/<disk_name> represents the device number of disk | ||
77 | * 4) /dev/<disk_name><decimal> represents the device number | ||
78 | * of partition - device number of disk plus the partition number | ||
79 | * 5) /dev/<disk_name>p<decimal> - same as the above, that form is | ||
80 | * used when disk name of partitioned disk ends on a digit. | ||
81 | * | ||
82 | * If name doesn't have fall into the categories above, we return 0. | ||
83 | * sysfs is used to check if something is a disk name - it has | ||
84 | * all known disks under bus/block/devices. If the disk name | ||
85 | * contains slashes, name of driverfs node has them replaced with | ||
86 | * bangs. try_name() does the actual checks, assuming that sysfs | ||
87 | * is mounted on /sys. | ||
88 | * | ||
89 | * Note that cases (1) and (2) are already handled by the kernel, | ||
90 | * so we can ifdef them out, provided that we check real-root-dev | ||
91 | * first. | ||
92 | */ | ||
93 | |||
94 | dev_t | ||
95 | name_to_dev_t(char *name) | ||
96 | { | ||
97 | char s[32]; | ||
98 | char *p; | ||
99 | dev_t res = 0; | ||
100 | int part; | ||
101 | |||
102 | if (strncmp(name, "/dev/", 5) != 0) { | ||
103 | #if 1 /* kernel used to do this */ | ||
104 | unsigned maj, min; | ||
105 | |||
106 | if (sscanf(name, "%u:%u", &maj, &min) == 2) { | ||
107 | res = makedev(maj, min); | ||
108 | if (maj != major(res) || min != minor(res)) | ||
109 | return 0; | ||
110 | } else { | ||
111 | res = strtoul(name, &p, 16); | ||
112 | if (*p) | ||
113 | return 0; | ||
114 | } | ||
115 | #endif | ||
116 | return res; | ||
117 | } | ||
118 | |||
119 | name += 5; | ||
120 | |||
121 | #if 1 /* kernel used to do this */ | ||
122 | if (strcmp(name, "nfs") == 0) | ||
123 | return makedev(0, 255); | ||
124 | #endif | ||
125 | if (strchr(name, '/')) { | ||
126 | res = try_name(name, 1); | ||
127 | if (res) | ||
128 | return res; | ||
129 | } | ||
130 | |||
131 | if (strlen(name) > 31) | ||
132 | return 0; | ||
133 | strcpy(s, name); | ||
134 | for (p = s; *p; p++) | ||
135 | if (*p == '/') | ||
136 | *p = '!'; | ||
137 | res = try_name(s, 0); | ||
138 | if (res) | ||
139 | return res; | ||
140 | |||
141 | while (p > s && isdigit(p[-1])) | ||
142 | p--; | ||
143 | if (p == s || !*p || *p == '0') | ||
144 | return 0; | ||
145 | part = strtoul(p, NULL, 10); | ||
146 | *p = '\0'; | ||
147 | res = try_name(s, part); | ||
148 | if (res) | ||
149 | return res; | ||
150 | |||
151 | if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p') | ||
152 | return 0; | ||
153 | p[-1] = '\0'; | ||
154 | return try_name(s, part); | ||
155 | } |