| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | } |