Root/
1 | /* |
2 | * Many of the syscalls used in this file expect some of the arguments |
3 | * to be __user pointers not __kernel pointers. To limit the sparse |
4 | * noise, turn off sparse checking for this file. |
5 | */ |
6 | #ifdef __CHECKER__ |
7 | #undef __CHECKER__ |
8 | #warning "Sparse checking disabled for this file" |
9 | #endif |
10 | |
11 | #include <linux/module.h> |
12 | #include <linux/sched.h> |
13 | #include <linux/ctype.h> |
14 | #include <linux/fd.h> |
15 | #include <linux/tty.h> |
16 | #include <linux/suspend.h> |
17 | #include <linux/root_dev.h> |
18 | #include <linux/security.h> |
19 | #include <linux/delay.h> |
20 | #include <linux/genhd.h> |
21 | #include <linux/mount.h> |
22 | #include <linux/device.h> |
23 | #include <linux/init.h> |
24 | #include <linux/fs.h> |
25 | #include <linux/initrd.h> |
26 | #include <linux/async.h> |
27 | #include <linux/fs_struct.h> |
28 | #include <linux/slab.h> |
29 | |
30 | #include <linux/nfs_fs.h> |
31 | #include <linux/nfs_fs_sb.h> |
32 | #include <linux/nfs_mount.h> |
33 | |
34 | #include "do_mounts.h" |
35 | |
36 | int __initdata rd_doload; /* 1 = load RAM disk, 0 = don't load */ |
37 | |
38 | int root_mountflags = MS_RDONLY | MS_SILENT; |
39 | static char * __initdata root_device_name; |
40 | static char __initdata saved_root_name[64]; |
41 | static int root_wait; |
42 | |
43 | dev_t ROOT_DEV; |
44 | |
45 | static int __init load_ramdisk(char *str) |
46 | { |
47 | rd_doload = simple_strtol(str,NULL,0) & 3; |
48 | return 1; |
49 | } |
50 | __setup("load_ramdisk=", load_ramdisk); |
51 | |
52 | static int __init readonly(char *str) |
53 | { |
54 | if (*str) |
55 | return 0; |
56 | root_mountflags |= MS_RDONLY; |
57 | return 1; |
58 | } |
59 | |
60 | static int __init readwrite(char *str) |
61 | { |
62 | if (*str) |
63 | return 0; |
64 | root_mountflags &= ~MS_RDONLY; |
65 | return 1; |
66 | } |
67 | |
68 | __setup("ro", readonly); |
69 | __setup("rw", readwrite); |
70 | |
71 | #ifdef CONFIG_BLOCK |
72 | struct uuidcmp { |
73 | const char *uuid; |
74 | int len; |
75 | }; |
76 | |
77 | /** |
78 | * match_dev_by_uuid - callback for finding a partition using its uuid |
79 | * @dev: device passed in by the caller |
80 | * @data: opaque pointer to the desired struct uuidcmp to match |
81 | * |
82 | * Returns 1 if the device matches, and 0 otherwise. |
83 | */ |
84 | static int match_dev_by_uuid(struct device *dev, const void *data) |
85 | { |
86 | const struct uuidcmp *cmp = data; |
87 | struct hd_struct *part = dev_to_part(dev); |
88 | |
89 | if (!part->info) |
90 | goto no_match; |
91 | |
92 | if (strncasecmp(cmp->uuid, part->info->uuid, cmp->len)) |
93 | goto no_match; |
94 | |
95 | return 1; |
96 | no_match: |
97 | return 0; |
98 | } |
99 | |
100 | |
101 | /** |
102 | * devt_from_partuuid - looks up the dev_t of a partition by its UUID |
103 | * @uuid: char array containing ascii UUID |
104 | * |
105 | * The function will return the first partition which contains a matching |
106 | * UUID value in its partition_meta_info struct. This does not search |
107 | * by filesystem UUIDs. |
108 | * |
109 | * If @uuid is followed by a "/PARTNROFF=%d", then the number will be |
110 | * extracted and used as an offset from the partition identified by the UUID. |
111 | * |
112 | * Returns the matching dev_t on success or 0 on failure. |
113 | */ |
114 | static dev_t devt_from_partuuid(const char *uuid_str) |
115 | { |
116 | dev_t res = 0; |
117 | struct uuidcmp cmp; |
118 | struct device *dev = NULL; |
119 | struct gendisk *disk; |
120 | struct hd_struct *part; |
121 | int offset = 0; |
122 | bool clear_root_wait = false; |
123 | char *slash; |
124 | |
125 | cmp.uuid = uuid_str; |
126 | |
127 | slash = strchr(uuid_str, '/'); |
128 | /* Check for optional partition number offset attributes. */ |
129 | if (slash) { |
130 | char c = 0; |
131 | /* Explicitly fail on poor PARTUUID syntax. */ |
132 | if (sscanf(slash + 1, |
133 | "PARTNROFF=%d%c", &offset, &c) != 1) { |
134 | clear_root_wait = true; |
135 | goto done; |
136 | } |
137 | cmp.len = slash - uuid_str; |
138 | } else { |
139 | cmp.len = strlen(uuid_str); |
140 | } |
141 | |
142 | if (!cmp.len) { |
143 | clear_root_wait = true; |
144 | goto done; |
145 | } |
146 | |
147 | dev = class_find_device(&block_class, NULL, &cmp, |
148 | &match_dev_by_uuid); |
149 | if (!dev) |
150 | goto done; |
151 | |
152 | res = dev->devt; |
153 | |
154 | /* Attempt to find the partition by offset. */ |
155 | if (!offset) |
156 | goto no_offset; |
157 | |
158 | res = 0; |
159 | disk = part_to_disk(dev_to_part(dev)); |
160 | part = disk_get_part(disk, dev_to_part(dev)->partno + offset); |
161 | if (part) { |
162 | res = part_devt(part); |
163 | put_device(part_to_dev(part)); |
164 | } |
165 | |
166 | no_offset: |
167 | put_device(dev); |
168 | done: |
169 | if (clear_root_wait) { |
170 | pr_err("VFS: PARTUUID= is invalid.\n" |
171 | "Expected PARTUUID=<valid-uuid-id>[/PARTNROFF=%%d]\n"); |
172 | if (root_wait) |
173 | pr_err("Disabling rootwait; root= is invalid.\n"); |
174 | root_wait = 0; |
175 | } |
176 | return res; |
177 | } |
178 | #endif |
179 | |
180 | /* |
181 | * Convert a name into device number. We accept the following variants: |
182 | * |
183 | * 1) device number in hexadecimal represents itself |
184 | * 2) /dev/nfs represents Root_NFS (0xff) |
185 | * 3) /dev/<disk_name> represents the device number of disk |
186 | * 4) /dev/<disk_name><decimal> represents the device number |
187 | * of partition - device number of disk plus the partition number |
188 | * 5) /dev/<disk_name>p<decimal> - same as the above, that form is |
189 | * used when disk name of partitioned disk ends on a digit. |
190 | * 6) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representing the |
191 | * unique id of a partition if the partition table provides it. |
192 | * The UUID may be either an EFI/GPT UUID, or refer to an MSDOS |
193 | * partition using the format SSSSSSSS-PP, where SSSSSSSS is a zero- |
194 | * filled hex representation of the 32-bit "NT disk signature", and PP |
195 | * is a zero-filled hex representation of the 1-based partition number. |
196 | * 7) PARTUUID=<UUID>/PARTNROFF=<int> to select a partition in relation to |
197 | * a partition with a known unique id. |
198 | * |
199 | * If name doesn't have fall into the categories above, we return (0,0). |
200 | * block_class is used to check if something is a disk name. If the disk |
201 | * name contains slashes, the device name has them replaced with |
202 | * bangs. |
203 | */ |
204 | |
205 | dev_t name_to_dev_t(char *name) |
206 | { |
207 | char s[32]; |
208 | char *p; |
209 | dev_t res = 0; |
210 | int part; |
211 | |
212 | #ifdef CONFIG_BLOCK |
213 | if (strncmp(name, "PARTUUID=", 9) == 0) { |
214 | name += 9; |
215 | res = devt_from_partuuid(name); |
216 | if (!res) |
217 | goto fail; |
218 | goto done; |
219 | } |
220 | #endif |
221 | |
222 | if (strncmp(name, "/dev/", 5) != 0) { |
223 | unsigned maj, min; |
224 | |
225 | if (sscanf(name, "%u:%u", &maj, &min) == 2) { |
226 | res = MKDEV(maj, min); |
227 | if (maj != MAJOR(res) || min != MINOR(res)) |
228 | goto fail; |
229 | } else { |
230 | res = new_decode_dev(simple_strtoul(name, &p, 16)); |
231 | if (*p) |
232 | goto fail; |
233 | } |
234 | goto done; |
235 | } |
236 | |
237 | name += 5; |
238 | res = Root_NFS; |
239 | if (strcmp(name, "nfs") == 0) |
240 | goto done; |
241 | res = Root_RAM0; |
242 | if (strcmp(name, "ram") == 0) |
243 | goto done; |
244 | |
245 | if (strlen(name) > 31) |
246 | goto fail; |
247 | strcpy(s, name); |
248 | for (p = s; *p; p++) |
249 | if (*p == '/') |
250 | *p = '!'; |
251 | res = blk_lookup_devt(s, 0); |
252 | if (res) |
253 | goto done; |
254 | |
255 | /* |
256 | * try non-existent, but valid partition, which may only exist |
257 | * after revalidating the disk, like partitioned md devices |
258 | */ |
259 | while (p > s && isdigit(p[-1])) |
260 | p--; |
261 | if (p == s || !*p || *p == '0') |
262 | goto fail; |
263 | |
264 | /* try disk name without <part number> */ |
265 | part = simple_strtoul(p, NULL, 10); |
266 | *p = '\0'; |
267 | res = blk_lookup_devt(s, part); |
268 | if (res) |
269 | goto done; |
270 | |
271 | /* try disk name without p<part number> */ |
272 | if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p') |
273 | goto fail; |
274 | p[-1] = '\0'; |
275 | res = blk_lookup_devt(s, part); |
276 | if (res) |
277 | goto done; |
278 | |
279 | fail: |
280 | return 0; |
281 | done: |
282 | return res; |
283 | } |
284 | |
285 | static int __init root_dev_setup(char *line) |
286 | { |
287 | strlcpy(saved_root_name, line, sizeof(saved_root_name)); |
288 | return 1; |
289 | } |
290 | |
291 | __setup("root=", root_dev_setup); |
292 | |
293 | static int __init rootwait_setup(char *str) |
294 | { |
295 | if (*str) |
296 | return 0; |
297 | root_wait = 1; |
298 | return 1; |
299 | } |
300 | |
301 | __setup("rootwait", rootwait_setup); |
302 | |
303 | static char * __initdata root_mount_data; |
304 | static int __init root_data_setup(char *str) |
305 | { |
306 | root_mount_data = str; |
307 | return 1; |
308 | } |
309 | |
310 | static char * __initdata root_fs_names; |
311 | static int __init fs_names_setup(char *str) |
312 | { |
313 | root_fs_names = str; |
314 | return 1; |
315 | } |
316 | |
317 | static unsigned int __initdata root_delay; |
318 | static int __init root_delay_setup(char *str) |
319 | { |
320 | root_delay = simple_strtoul(str, NULL, 0); |
321 | return 1; |
322 | } |
323 | |
324 | __setup("rootflags=", root_data_setup); |
325 | __setup("rootfstype=", fs_names_setup); |
326 | __setup("rootdelay=", root_delay_setup); |
327 | |
328 | static void __init get_fs_names(char *page) |
329 | { |
330 | char *s = page; |
331 | |
332 | if (root_fs_names) { |
333 | strcpy(page, root_fs_names); |
334 | while (*s++) { |
335 | if (s[-1] == ',') |
336 | s[-1] = '\0'; |
337 | } |
338 | } else { |
339 | int len = get_filesystem_list(page); |
340 | char *p, *next; |
341 | |
342 | page[len] = '\0'; |
343 | for (p = page-1; p; p = next) { |
344 | next = strchr(++p, '\n'); |
345 | if (*p++ != '\t') |
346 | continue; |
347 | while ((*s++ = *p++) != '\n') |
348 | ; |
349 | s[-1] = '\0'; |
350 | } |
351 | } |
352 | *s = '\0'; |
353 | } |
354 | |
355 | static int __init do_mount_root(char *name, char *fs, int flags, void *data) |
356 | { |
357 | struct super_block *s; |
358 | int err = sys_mount(name, "/root", fs, flags, data); |
359 | if (err) |
360 | return err; |
361 | |
362 | sys_chdir("/root"); |
363 | s = current->fs->pwd.dentry->d_sb; |
364 | ROOT_DEV = s->s_dev; |
365 | printk(KERN_INFO |
366 | "VFS: Mounted root (%s filesystem)%s on device %u:%u.\n", |
367 | s->s_type->name, |
368 | s->s_flags & MS_RDONLY ? " readonly" : "", |
369 | MAJOR(ROOT_DEV), MINOR(ROOT_DEV)); |
370 | return 0; |
371 | } |
372 | |
373 | void __init mount_block_root(char *name, int flags) |
374 | { |
375 | struct page *page = alloc_page(GFP_KERNEL | |
376 | __GFP_NOTRACK_FALSE_POSITIVE); |
377 | char *fs_names = page_address(page); |
378 | char *p; |
379 | #ifdef CONFIG_BLOCK |
380 | char b[BDEVNAME_SIZE]; |
381 | #else |
382 | const char *b = name; |
383 | #endif |
384 | |
385 | get_fs_names(fs_names); |
386 | retry: |
387 | for (p = fs_names; *p; p += strlen(p)+1) { |
388 | int err = do_mount_root(name, p, flags, root_mount_data); |
389 | switch (err) { |
390 | case 0: |
391 | goto out; |
392 | case -EACCES: |
393 | flags |= MS_RDONLY; |
394 | goto retry; |
395 | case -EINVAL: |
396 | continue; |
397 | } |
398 | /* |
399 | * Allow the user to distinguish between failed sys_open |
400 | * and bad superblock on root device. |
401 | * and give them a list of the available devices |
402 | */ |
403 | #ifdef CONFIG_BLOCK |
404 | __bdevname(ROOT_DEV, b); |
405 | #endif |
406 | printk("VFS: Cannot open root device \"%s\" or %s: error %d\n", |
407 | root_device_name, b, err); |
408 | printk("Please append a correct \"root=\" boot option; here are the available partitions:\n"); |
409 | |
410 | printk_all_partitions(); |
411 | #ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT |
412 | printk("DEBUG_BLOCK_EXT_DEVT is enabled, you need to specify " |
413 | "explicit textual name for \"root=\" boot option.\n"); |
414 | #endif |
415 | panic("VFS: Unable to mount root fs on %s", b); |
416 | } |
417 | |
418 | printk("List of all partitions:\n"); |
419 | printk_all_partitions(); |
420 | printk("No filesystem could mount root, tried: "); |
421 | for (p = fs_names; *p; p += strlen(p)+1) |
422 | printk(" %s", p); |
423 | printk("\n"); |
424 | #ifdef CONFIG_BLOCK |
425 | __bdevname(ROOT_DEV, b); |
426 | #endif |
427 | panic("VFS: Unable to mount root fs on %s", b); |
428 | out: |
429 | put_page(page); |
430 | } |
431 | |
432 | #ifdef CONFIG_ROOT_NFS |
433 | |
434 | #define NFSROOT_TIMEOUT_MIN 5 |
435 | #define NFSROOT_TIMEOUT_MAX 30 |
436 | #define NFSROOT_RETRY_MAX 5 |
437 | |
438 | static int __init mount_nfs_root(void) |
439 | { |
440 | char *root_dev, *root_data; |
441 | unsigned int timeout; |
442 | int try, err; |
443 | |
444 | err = nfs_root_data(&root_dev, &root_data); |
445 | if (err != 0) |
446 | return 0; |
447 | |
448 | /* |
449 | * The server or network may not be ready, so try several |
450 | * times. Stop after a few tries in case the client wants |
451 | * to fall back to other boot methods. |
452 | */ |
453 | timeout = NFSROOT_TIMEOUT_MIN; |
454 | for (try = 1; ; try++) { |
455 | err = do_mount_root(root_dev, "nfs", |
456 | root_mountflags, root_data); |
457 | if (err == 0) |
458 | return 1; |
459 | if (try > NFSROOT_RETRY_MAX) |
460 | break; |
461 | |
462 | /* Wait, in case the server refused us immediately */ |
463 | ssleep(timeout); |
464 | timeout <<= 1; |
465 | if (timeout > NFSROOT_TIMEOUT_MAX) |
466 | timeout = NFSROOT_TIMEOUT_MAX; |
467 | } |
468 | return 0; |
469 | } |
470 | #endif |
471 | |
472 | #if defined(CONFIG_BLK_DEV_RAM) || defined(CONFIG_BLK_DEV_FD) |
473 | void __init change_floppy(char *fmt, ...) |
474 | { |
475 | struct termios termios; |
476 | char buf[80]; |
477 | char c; |
478 | int fd; |
479 | va_list args; |
480 | va_start(args, fmt); |
481 | vsprintf(buf, fmt, args); |
482 | va_end(args); |
483 | fd = sys_open("/dev/root", O_RDWR | O_NDELAY, 0); |
484 | if (fd >= 0) { |
485 | sys_ioctl(fd, FDEJECT, 0); |
486 | sys_close(fd); |
487 | } |
488 | printk(KERN_NOTICE "VFS: Insert %s and press ENTER\n", buf); |
489 | fd = sys_open("/dev/console", O_RDWR, 0); |
490 | if (fd >= 0) { |
491 | sys_ioctl(fd, TCGETS, (long)&termios); |
492 | termios.c_lflag &= ~ICANON; |
493 | sys_ioctl(fd, TCSETSF, (long)&termios); |
494 | sys_read(fd, &c, 1); |
495 | termios.c_lflag |= ICANON; |
496 | sys_ioctl(fd, TCSETSF, (long)&termios); |
497 | sys_close(fd); |
498 | } |
499 | } |
500 | #endif |
501 | |
502 | void __init mount_root(void) |
503 | { |
504 | #ifdef CONFIG_ROOT_NFS |
505 | if (ROOT_DEV == Root_NFS) { |
506 | if (mount_nfs_root()) |
507 | return; |
508 | |
509 | printk(KERN_ERR "VFS: Unable to mount root fs via NFS, trying floppy.\n"); |
510 | ROOT_DEV = Root_FD0; |
511 | } |
512 | #endif |
513 | #ifdef CONFIG_BLK_DEV_FD |
514 | if (MAJOR(ROOT_DEV) == FLOPPY_MAJOR) { |
515 | /* rd_doload is 2 for a dual initrd/ramload setup */ |
516 | if (rd_doload==2) { |
517 | if (rd_load_disk(1)) { |
518 | ROOT_DEV = Root_RAM1; |
519 | root_device_name = NULL; |
520 | } |
521 | } else |
522 | change_floppy("root floppy"); |
523 | } |
524 | #endif |
525 | #ifdef CONFIG_BLOCK |
526 | create_dev("/dev/root", ROOT_DEV); |
527 | mount_block_root("/dev/root", root_mountflags); |
528 | #endif |
529 | } |
530 | |
531 | /* |
532 | * Prepare the namespace - decide what/where to mount, load ramdisks, etc. |
533 | */ |
534 | void __init prepare_namespace(void) |
535 | { |
536 | int is_floppy; |
537 | |
538 | if (root_delay) { |
539 | printk(KERN_INFO "Waiting %dsec before mounting root device...\n", |
540 | root_delay); |
541 | ssleep(root_delay); |
542 | } |
543 | |
544 | /* |
545 | * wait for the known devices to complete their probing |
546 | * |
547 | * Note: this is a potential source of long boot delays. |
548 | * For example, it is not atypical to wait 5 seconds here |
549 | * for the touchpad of a laptop to initialize. |
550 | */ |
551 | wait_for_device_probe(); |
552 | |
553 | md_run_setup(); |
554 | |
555 | if (saved_root_name[0]) { |
556 | root_device_name = saved_root_name; |
557 | if (!strncmp(root_device_name, "mtd", 3) || |
558 | !strncmp(root_device_name, "ubi", 3)) { |
559 | mount_block_root(root_device_name, root_mountflags); |
560 | goto out; |
561 | } |
562 | ROOT_DEV = name_to_dev_t(root_device_name); |
563 | if (strncmp(root_device_name, "/dev/", 5) == 0) |
564 | root_device_name += 5; |
565 | } |
566 | |
567 | if (initrd_load()) |
568 | goto out; |
569 | |
570 | /* wait for any asynchronous scanning to complete */ |
571 | if ((ROOT_DEV == 0) && root_wait) { |
572 | printk(KERN_INFO "Waiting for root device %s...\n", |
573 | saved_root_name); |
574 | while (driver_probe_done() != 0 || |
575 | (ROOT_DEV = name_to_dev_t(saved_root_name)) == 0) |
576 | msleep(100); |
577 | async_synchronize_full(); |
578 | } |
579 | |
580 | is_floppy = MAJOR(ROOT_DEV) == FLOPPY_MAJOR; |
581 | |
582 | if (is_floppy && rd_doload && rd_load_disk(0)) |
583 | ROOT_DEV = Root_RAM0; |
584 | |
585 | mount_root(); |
586 | out: |
587 | devtmpfs_mount("dev"); |
588 | sys_mount(".", "/", NULL, MS_MOVE, NULL); |
589 | sys_chroot("."); |
590 | } |
591 |
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