Contents of /alx-src/tags/kernel26-2.6.12-alx-r9/init/do_mounts_devfs.c
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Wed Mar 4 11:03:09 2009 UTC (15 years, 6 months ago) by niro
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File size: 2862 byte(s)
Wed Mar 4 11:03:09 2009 UTC (15 years, 6 months ago) by niro
File MIME type: text/plain
File size: 2862 byte(s)
Tag kernel26-2.6.12-alx-r9
1 | |
2 | #include <linux/kernel.h> |
3 | #include <linux/dirent.h> |
4 | #include <linux/string.h> |
5 | |
6 | #include "do_mounts.h" |
7 | |
8 | void __init mount_devfs(void) |
9 | { |
10 | sys_mount("devfs", "/dev", "devfs", 0, NULL); |
11 | } |
12 | |
13 | void __init umount_devfs(char *path) |
14 | { |
15 | sys_umount(path, 0); |
16 | } |
17 | |
18 | /* |
19 | * If the dir will fit in *buf, return its length. If it won't fit, return |
20 | * zero. Return -ve on error. |
21 | */ |
22 | static int __init do_read_dir(int fd, void *buf, int len) |
23 | { |
24 | long bytes, n; |
25 | char *p = buf; |
26 | sys_lseek(fd, 0, 0); |
27 | |
28 | for (bytes = 0; bytes < len; bytes += n) { |
29 | n = sys_getdents64(fd, (struct linux_dirent64 *)(p + bytes), |
30 | len - bytes); |
31 | if (n < 0) |
32 | return n; |
33 | if (n == 0) |
34 | return bytes; |
35 | } |
36 | return 0; |
37 | } |
38 | |
39 | /* |
40 | * Try to read all of a directory. Returns the contents at *p, which |
41 | * is kmalloced memory. Returns the number of bytes read at *len. Returns |
42 | * NULL on error. |
43 | */ |
44 | static void * __init read_dir(char *path, int *len) |
45 | { |
46 | int size; |
47 | int fd = sys_open(path, 0, 0); |
48 | |
49 | *len = 0; |
50 | if (fd < 0) |
51 | return NULL; |
52 | |
53 | for (size = 1 << 9; size <= (PAGE_SIZE << MAX_ORDER); size <<= 1) { |
54 | void *p = kmalloc(size, GFP_KERNEL); |
55 | int n; |
56 | if (!p) |
57 | break; |
58 | n = do_read_dir(fd, p, size); |
59 | if (n > 0) { |
60 | sys_close(fd); |
61 | *len = n; |
62 | return p; |
63 | } |
64 | kfree(p); |
65 | if (n == -EINVAL) |
66 | continue; /* Try a larger buffer */ |
67 | if (n < 0) |
68 | break; |
69 | } |
70 | sys_close(fd); |
71 | return NULL; |
72 | } |
73 | |
74 | /* |
75 | * recursively scan <path>, looking for a device node of type <dev> |
76 | */ |
77 | static int __init find_in_devfs(char *path, unsigned dev) |
78 | { |
79 | char *end = path + strlen(path); |
80 | int rest = path + 64 - end; |
81 | int size; |
82 | char *p = read_dir(path, &size); |
83 | char *s; |
84 | |
85 | if (!p) |
86 | return -1; |
87 | for (s = p; s < p + size; s += ((struct linux_dirent64 *)s)->d_reclen) { |
88 | struct linux_dirent64 *d = (struct linux_dirent64 *)s; |
89 | if (strlen(d->d_name) + 2 > rest) |
90 | continue; |
91 | switch (d->d_type) { |
92 | case DT_BLK: |
93 | sprintf(end, "/%s", d->d_name); |
94 | if (bstat(path) != dev) |
95 | break; |
96 | kfree(p); |
97 | return 0; |
98 | case DT_DIR: |
99 | if (strcmp(d->d_name, ".") == 0) |
100 | break; |
101 | if (strcmp(d->d_name, "..") == 0) |
102 | break; |
103 | sprintf(end, "/%s", d->d_name); |
104 | if (find_in_devfs(path, dev) < 0) |
105 | break; |
106 | kfree(p); |
107 | return 0; |
108 | } |
109 | } |
110 | kfree(p); |
111 | return -1; |
112 | } |
113 | |
114 | /* |
115 | * create a device node called <name> which points to |
116 | * <devfs_name> if possible, otherwise find a device node |
117 | * which matches <dev> and make <name> a symlink pointing to it. |
118 | */ |
119 | int __init create_dev(char *name, dev_t dev, char *devfs_name) |
120 | { |
121 | char path[64]; |
122 | |
123 | sys_unlink(name); |
124 | if (devfs_name && devfs_name[0]) { |
125 | if (strncmp(devfs_name, "/dev/", 5) == 0) |
126 | devfs_name += 5; |
127 | sprintf(path, "/dev/%s", devfs_name); |
128 | if (sys_access(path, 0) == 0) |
129 | return sys_symlink(devfs_name, name); |
130 | } |
131 | if (!dev) |
132 | return -1; |
133 | strcpy(path, "/dev"); |
134 | if (find_in_devfs(path, new_encode_dev(dev)) < 0) |
135 | return -1; |
136 | return sys_symlink(path + 5, name); |
137 | } |