[PATCH] Philip Gladstone has moved
[linux-2.6.git] / init / do_mounts_devfs.c
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 }