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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
36int __initdata rd_doload; /* 1 = load RAM disk, 0 = don't load */
37
38int root_mountflags = MS_RDONLY | MS_SILENT;
39static char * __initdata root_device_name;
40static char __initdata saved_root_name[64];
41static int root_wait;
42
43dev_t ROOT_DEV;
44
45static 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
52static int __init readonly(char *str)
53{
54 if (*str)
55 return 0;
56 root_mountflags |= MS_RDONLY;
57 return 1;
58}
59
60static 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/**
73 * match_dev_by_uuid - callback for finding a partition using its uuid
74 * @dev: device passed in by the caller
75 * @data: opaque pointer to a 36 byte char array with a UUID
76 *
77 * Returns 1 if the device matches, and 0 otherwise.
78 */
79static int match_dev_by_uuid(struct device *dev, void *data)
80{
81 u8 *uuid = data;
82 struct hd_struct *part = dev_to_part(dev);
83
84 if (!part->info)
85 goto no_match;
86
87 if (memcmp(uuid, part->info->uuid, sizeof(part->info->uuid)))
88 goto no_match;
89
90 return 1;
91no_match:
92 return 0;
93}
94
95
96/**
97 * devt_from_partuuid - looks up the dev_t of a partition by its UUID
98 * @uuid: min 36 byte char array containing a hex ascii UUID
99 *
100 * The function will return the first partition which contains a matching
101 * UUID value in its partition_meta_info struct. This does not search
102 * by filesystem UUIDs.
103 *
104 * If @uuid is followed by a "/PARTNROFF=%d", then the number will be
105 * extracted and used as an offset from the partition identified by the UUID.
106 *
107 * Returns the matching dev_t on success or 0 on failure.
108 */
109static dev_t devt_from_partuuid(char *uuid_str)
110{
111 dev_t res = 0;
112 struct device *dev = NULL;
113 u8 uuid[16];
114 struct gendisk *disk;
115 struct hd_struct *part;
116 int offset = 0;
117
118 if (strlen(uuid_str) < 36)
119 goto done;
120
121 /* Check for optional partition number offset attributes. */
122 if (uuid_str[36]) {
123 char c = 0;
124 /* Explicitly fail on poor PARTUUID syntax. */
125 if (sscanf(&uuid_str[36],
126 "/PARTNROFF=%d%c", &offset, &c) != 1) {
127 printk(KERN_ERR "VFS: PARTUUID= is invalid.\n"
128 "Expected PARTUUID=<valid-uuid-id>[/PARTNROFF=%%d]\n");
129 if (root_wait)
130 printk(KERN_ERR
131 "Disabling rootwait; root= is invalid.\n");
132 root_wait = 0;
133 goto done;
134 }
135 }
136
137 /* Pack the requested UUID in the expected format. */
138 part_pack_uuid(uuid_str, uuid);
139
140 dev = class_find_device(&block_class, NULL, uuid, &match_dev_by_uuid);
141 if (!dev)
142 goto done;
143
144 res = dev->devt;
145
146 /* Attempt to find the partition by offset. */
147 if (!offset)
148 goto no_offset;
149
150 res = 0;
151 disk = part_to_disk(dev_to_part(dev));
152 part = disk_get_part(disk, dev_to_part(dev)->partno + offset);
153 if (part) {
154 res = part_devt(part);
155 put_device(part_to_dev(part));
156 }
157
158no_offset:
159 put_device(dev);
160done:
161 return res;
162}
163#endif
164
165/*
166 * Convert a name into device number. We accept the following variants:
167 *
168 * 1) device number in hexadecimal represents itself
169 * 2) /dev/nfs represents Root_NFS (0xff)
170 * 3) /dev/<disk_name> represents the device number of disk
171 * 4) /dev/<disk_name><decimal> represents the device number
172 * of partition - device number of disk plus the partition number
173 * 5) /dev/<disk_name>p<decimal> - same as the above, that form is
174 * used when disk name of partitioned disk ends on a digit.
175 * 6) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representing the
176 * unique id of a partition if the partition table provides it.
177 * 7) PARTUUID=<UUID>/PARTNROFF=<int> to select a partition in relation to
178 * a partition with a known unique id.
179 *
180 * If name doesn't have fall into the categories above, we return (0,0).
181 * block_class is used to check if something is a disk name. If the disk
182 * name contains slashes, the device name has them replaced with
183 * bangs.
184 */
185
186dev_t name_to_dev_t(char *name)
187{
188 char s[32];
189 char *p;
190 dev_t res = 0;
191 int part;
192
193#ifdef CONFIG_BLOCK
194 if (strncmp(name, "PARTUUID=", 9) == 0) {
195 name += 9;
196 res = devt_from_partuuid(name);
197 if (!res)
198 goto fail;
199 goto done;
200 }
201#endif
202
203 if (strncmp(name, "/dev/", 5) != 0) {
204 unsigned maj, min;
205
206 if (sscanf(name, "%u:%u", &maj, &min) == 2) {
207 res = MKDEV(maj, min);
208 if (maj != MAJOR(res) || min != MINOR(res))
209 goto fail;
210 } else {
211 res = new_decode_dev(simple_strtoul(name, &p, 16));
212 if (*p)
213 goto fail;
214 }
215 goto done;
216 }
217
218 name += 5;
219 res = Root_NFS;
220 if (strcmp(name, "nfs") == 0)
221 goto done;
222 res = Root_RAM0;
223 if (strcmp(name, "ram") == 0)
224 goto done;
225
226 if (strlen(name) > 31)
227 goto fail;
228 strcpy(s, name);
229 for (p = s; *p; p++)
230 if (*p == '/')
231 *p = '!';
232 res = blk_lookup_devt(s, 0);
233 if (res)
234 goto done;
235
236 /*
237 * try non-existent, but valid partition, which may only exist
238 * after revalidating the disk, like partitioned md devices
239 */
240 while (p > s && isdigit(p[-1]))
241 p--;
242 if (p == s || !*p || *p == '0')
243 goto fail;
244
245 /* try disk name without <part number> */
246 part = simple_strtoul(p, NULL, 10);
247 *p = '\0';
248 res = blk_lookup_devt(s, part);
249 if (res)
250 goto done;
251
252 /* try disk name without p<part number> */
253 if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p')
254 goto fail;
255 p[-1] = '\0';
256 res = blk_lookup_devt(s, part);
257 if (res)
258 goto done;
259
260fail:
261 return 0;
262done:
263 return res;
264}
265
266static int __init root_dev_setup(char *line)
267{
268 strlcpy(saved_root_name, line, sizeof(saved_root_name));
269 return 1;
270}
271
272__setup("root=", root_dev_setup);
273
274static int __init rootwait_setup(char *str)
275{
276 if (*str)
277 return 0;
278 root_wait = 1;
279 return 1;
280}
281
282__setup("rootwait", rootwait_setup);
283
284static char * __initdata root_mount_data;
285static int __init root_data_setup(char *str)
286{
287 root_mount_data = str;
288 return 1;
289}
290
291static char * __initdata root_fs_names;
292static int __init fs_names_setup(char *str)
293{
294 root_fs_names = str;
295 return 1;
296}
297
298static unsigned int __initdata root_delay;
299static int __init root_delay_setup(char *str)
300{
301 root_delay = simple_strtoul(str, NULL, 0);
302 return 1;
303}
304
305__setup("rootflags=", root_data_setup);
306__setup("rootfstype=", fs_names_setup);
307__setup("rootdelay=", root_delay_setup);
308
309static void __init get_fs_names(char *page)
310{
311 char *s = page;
312
313 if (root_fs_names) {
314 strcpy(page, root_fs_names);
315 while (*s++) {
316 if (s[-1] == ',')
317 s[-1] = '\0';
318 }
319 } else {
320 int len = get_filesystem_list(page);
321 char *p, *next;
322
323 page[len] = '\0';
324 for (p = page-1; p; p = next) {
325 next = strchr(++p, '\n');
326 if (*p++ != '\t')
327 continue;
328 while ((*s++ = *p++) != '\n')
329 ;
330 s[-1] = '\0';
331 }
332 }
333 *s = '\0';
334}
335
336static int __init do_mount_root(char *name, char *fs, int flags, void *data)
337{
338 struct super_block *s;
339 int err = sys_mount(name, "/root", fs, flags, data);
340 if (err)
341 return err;
342
343 sys_chdir("/root");
344 s = current->fs->pwd.dentry->d_sb;
345 ROOT_DEV = s->s_dev;
346 printk(KERN_INFO
347 "VFS: Mounted root (%s filesystem)%s on device %u:%u.\n",
348 s->s_type->name,
349 s->s_flags & MS_RDONLY ? " readonly" : "",
350 MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
351 return 0;
352}
353
354void __init mount_block_root(char *name, int flags)
355{
356 char *fs_names = __getname_gfp(GFP_KERNEL
357 | __GFP_NOTRACK_FALSE_POSITIVE);
358 char *p;
359#ifdef CONFIG_BLOCK
360 char b[BDEVNAME_SIZE];
361#else
362 const char *b = name;
363#endif
364
365 get_fs_names(fs_names);
366retry:
367 for (p = fs_names; *p; p += strlen(p)+1) {
368 int err = do_mount_root(name, p, flags, root_mount_data);
369 switch (err) {
370 case 0:
371 goto out;
372 case -EACCES:
373 flags |= MS_RDONLY;
374 goto retry;
375 case -EINVAL:
376 continue;
377 }
378 /*
379 * Allow the user to distinguish between failed sys_open
380 * and bad superblock on root device.
381 * and give them a list of the available devices
382 */
383#ifdef CONFIG_BLOCK
384 __bdevname(ROOT_DEV, b);
385#endif
386 printk("VFS: Cannot open root device \"%s\" or %s: error %d\n",
387 root_device_name, b, err);
388 printk("Please append a correct \"root=\" boot option; here are the available partitions:\n");
389
390 printk_all_partitions();
391#ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT
392 printk("DEBUG_BLOCK_EXT_DEVT is enabled, you need to specify "
393 "explicit textual name for \"root=\" boot option.\n");
394#endif
395 panic("VFS: Unable to mount root fs on %s", b);
396 }
397
398 printk("List of all partitions:\n");
399 printk_all_partitions();
400 printk("No filesystem could mount root, tried: ");
401 for (p = fs_names; *p; p += strlen(p)+1)
402 printk(" %s", p);
403 printk("\n");
404#ifdef CONFIG_BLOCK
405 __bdevname(ROOT_DEV, b);
406#endif
407 panic("VFS: Unable to mount root fs on %s", b);
408out:
409 putname(fs_names);
410}
411
412#ifdef CONFIG_ROOT_NFS
413
414#define NFSROOT_TIMEOUT_MIN 5
415#define NFSROOT_TIMEOUT_MAX 30
416#define NFSROOT_RETRY_MAX 5
417
418static int __init mount_nfs_root(void)
419{
420 char *root_dev, *root_data;
421 unsigned int timeout;
422 int try, err;
423
424 err = nfs_root_data(&root_dev, &root_data);
425 if (err != 0)
426 return 0;
427
428 /*
429 * The server or network may not be ready, so try several
430 * times. Stop after a few tries in case the client wants
431 * to fall back to other boot methods.
432 */
433 timeout = NFSROOT_TIMEOUT_MIN;
434 for (try = 1; ; try++) {
435 err = do_mount_root(root_dev, "nfs",
436 root_mountflags, root_data);
437 if (err == 0)
438 return 1;
439 if (try > NFSROOT_RETRY_MAX)
440 break;
441
442 /* Wait, in case the server refused us immediately */
443 ssleep(timeout);
444 timeout <<= 1;
445 if (timeout > NFSROOT_TIMEOUT_MAX)
446 timeout = NFSROOT_TIMEOUT_MAX;
447 }
448 return 0;
449}
450#endif
451
452#if defined(CONFIG_BLK_DEV_RAM) || defined(CONFIG_BLK_DEV_FD)
453void __init change_floppy(char *fmt, ...)
454{
455 struct termios termios;
456 char buf[80];
457 char c;
458 int fd;
459 va_list args;
460 va_start(args, fmt);
461 vsprintf(buf, fmt, args);
462 va_end(args);
463 fd = sys_open("/dev/root", O_RDWR | O_NDELAY, 0);
464 if (fd >= 0) {
465 sys_ioctl(fd, FDEJECT, 0);
466 sys_close(fd);
467 }
468 printk(KERN_NOTICE "VFS: Insert %s and press ENTER\n", buf);
469 fd = sys_open("/dev/console", O_RDWR, 0);
470 if (fd >= 0) {
471 sys_ioctl(fd, TCGETS, (long)&termios);
472 termios.c_lflag &= ~ICANON;
473 sys_ioctl(fd, TCSETSF, (long)&termios);
474 sys_read(fd, &c, 1);
475 termios.c_lflag |= ICANON;
476 sys_ioctl(fd, TCSETSF, (long)&termios);
477 sys_close(fd);
478 }
479}
480#endif
481
482void __init mount_root(void)
483{
484#ifdef CONFIG_ROOT_NFS
485 if (ROOT_DEV == Root_NFS) {
486 if (mount_nfs_root())
487 return;
488
489 printk(KERN_ERR "VFS: Unable to mount root fs via NFS, trying floppy.\n");
490 ROOT_DEV = Root_FD0;
491 }
492#endif
493#ifdef CONFIG_BLK_DEV_FD
494 if (MAJOR(ROOT_DEV) == FLOPPY_MAJOR) {
495 /* rd_doload is 2 for a dual initrd/ramload setup */
496 if (rd_doload==2) {
497 if (rd_load_disk(1)) {
498 ROOT_DEV = Root_RAM1;
499 root_device_name = NULL;
500 }
501 } else
502 change_floppy("root floppy");
503 }
504#endif
505#ifdef CONFIG_BLOCK
506 create_dev("/dev/root", ROOT_DEV);
507 mount_block_root("/dev/root", root_mountflags);
508#endif
509}
510
511/*
512 * Prepare the namespace - decide what/where to mount, load ramdisks, etc.
513 */
514void __init prepare_namespace(void)
515{
516 int is_floppy;
517
518 if (root_delay) {
519 printk(KERN_INFO "Waiting %dsec before mounting root device...\n",
520 root_delay);
521 ssleep(root_delay);
522 }
523
524 /*
525 * wait for the known devices to complete their probing
526 *
527 * Note: this is a potential source of long boot delays.
528 * For example, it is not atypical to wait 5 seconds here
529 * for the touchpad of a laptop to initialize.
530 */
531 wait_for_device_probe();
532
533 md_run_setup();
534
535 if (saved_root_name[0]) {
536 root_device_name = saved_root_name;
537 if (!strncmp(root_device_name, "mtd", 3) ||
538 !strncmp(root_device_name, "ubi", 3)) {
539 mount_block_root(root_device_name, root_mountflags);
540 goto out;
541 }
542 ROOT_DEV = name_to_dev_t(root_device_name);
543 if (strncmp(root_device_name, "/dev/", 5) == 0)
544 root_device_name += 5;
545 }
546
547 if (initrd_load())
548 goto out;
549
550 /* wait for any asynchronous scanning to complete */
551 if ((ROOT_DEV == 0) && root_wait) {
552 printk(KERN_INFO "Waiting for root device %s...\n",
553 saved_root_name);
554 while (driver_probe_done() != 0 ||
555 (ROOT_DEV = name_to_dev_t(saved_root_name)) == 0)
556 msleep(100);
557 async_synchronize_full();
558 }
559
560 is_floppy = MAJOR(ROOT_DEV) == FLOPPY_MAJOR;
561
562 if (is_floppy && rd_doload && rd_load_disk(0))
563 ROOT_DEV = Root_RAM0;
564
565 mount_root();
566out:
567 devtmpfs_mount("dev");
568 sys_mount(".", "/", NULL, MS_MOVE, NULL);
569 sys_chroot(".");
570}
1// SPDX-License-Identifier: GPL-2.0-only
2#include <linux/module.h>
3#include <linux/sched.h>
4#include <linux/ctype.h>
5#include <linux/fd.h>
6#include <linux/tty.h>
7#include <linux/suspend.h>
8#include <linux/root_dev.h>
9#include <linux/security.h>
10#include <linux/delay.h>
11#include <linux/genhd.h>
12#include <linux/mount.h>
13#include <linux/device.h>
14#include <linux/init.h>
15#include <linux/fs.h>
16#include <linux/initrd.h>
17#include <linux/async.h>
18#include <linux/fs_struct.h>
19#include <linux/slab.h>
20#include <linux/ramfs.h>
21#include <linux/shmem_fs.h>
22
23#include <linux/nfs_fs.h>
24#include <linux/nfs_fs_sb.h>
25#include <linux/nfs_mount.h>
26#include <linux/raid/detect.h>
27#include <uapi/linux/mount.h>
28
29#include "do_mounts.h"
30
31int root_mountflags = MS_RDONLY | MS_SILENT;
32static char * __initdata root_device_name;
33static char __initdata saved_root_name[64];
34static int root_wait;
35
36dev_t ROOT_DEV;
37
38static int __init load_ramdisk(char *str)
39{
40 pr_warn("ignoring the deprecated load_ramdisk= option\n");
41 return 1;
42}
43__setup("load_ramdisk=", load_ramdisk);
44
45static int __init readonly(char *str)
46{
47 if (*str)
48 return 0;
49 root_mountflags |= MS_RDONLY;
50 return 1;
51}
52
53static int __init readwrite(char *str)
54{
55 if (*str)
56 return 0;
57 root_mountflags &= ~MS_RDONLY;
58 return 1;
59}
60
61__setup("ro", readonly);
62__setup("rw", readwrite);
63
64#ifdef CONFIG_BLOCK
65struct uuidcmp {
66 const char *uuid;
67 int len;
68};
69
70/**
71 * match_dev_by_uuid - callback for finding a partition using its uuid
72 * @dev: device passed in by the caller
73 * @data: opaque pointer to the desired struct uuidcmp to match
74 *
75 * Returns 1 if the device matches, and 0 otherwise.
76 */
77static int match_dev_by_uuid(struct device *dev, const void *data)
78{
79 struct block_device *bdev = dev_to_bdev(dev);
80 const struct uuidcmp *cmp = data;
81
82 if (!bdev->bd_meta_info ||
83 strncasecmp(cmp->uuid, bdev->bd_meta_info->uuid, cmp->len))
84 return 0;
85 return 1;
86}
87
88/**
89 * devt_from_partuuid - looks up the dev_t of a partition by its UUID
90 * @uuid_str: char array containing ascii UUID
91 *
92 * The function will return the first partition which contains a matching
93 * UUID value in its partition_meta_info struct. This does not search
94 * by filesystem UUIDs.
95 *
96 * If @uuid_str is followed by a "/PARTNROFF=%d", then the number will be
97 * extracted and used as an offset from the partition identified by the UUID.
98 *
99 * Returns the matching dev_t on success or 0 on failure.
100 */
101static dev_t devt_from_partuuid(const char *uuid_str)
102{
103 struct uuidcmp cmp;
104 struct device *dev = NULL;
105 dev_t devt = 0;
106 int offset = 0;
107 char *slash;
108
109 cmp.uuid = uuid_str;
110
111 slash = strchr(uuid_str, '/');
112 /* Check for optional partition number offset attributes. */
113 if (slash) {
114 char c = 0;
115
116 /* Explicitly fail on poor PARTUUID syntax. */
117 if (sscanf(slash + 1, "PARTNROFF=%d%c", &offset, &c) != 1)
118 goto clear_root_wait;
119 cmp.len = slash - uuid_str;
120 } else {
121 cmp.len = strlen(uuid_str);
122 }
123
124 if (!cmp.len)
125 goto clear_root_wait;
126
127 dev = class_find_device(&block_class, NULL, &cmp, &match_dev_by_uuid);
128 if (!dev)
129 return 0;
130
131 if (offset) {
132 /*
133 * Attempt to find the requested partition by adding an offset
134 * to the partition number found by UUID.
135 */
136 devt = part_devt(dev_to_disk(dev),
137 dev_to_bdev(dev)->bd_partno + offset);
138 } else {
139 devt = dev->devt;
140 }
141
142 put_device(dev);
143 return devt;
144
145clear_root_wait:
146 pr_err("VFS: PARTUUID= is invalid.\n"
147 "Expected PARTUUID=<valid-uuid-id>[/PARTNROFF=%%d]\n");
148 if (root_wait)
149 pr_err("Disabling rootwait; root= is invalid.\n");
150 root_wait = 0;
151 return 0;
152}
153
154/**
155 * match_dev_by_label - callback for finding a partition using its label
156 * @dev: device passed in by the caller
157 * @data: opaque pointer to the label to match
158 *
159 * Returns 1 if the device matches, and 0 otherwise.
160 */
161static int match_dev_by_label(struct device *dev, const void *data)
162{
163 struct block_device *bdev = dev_to_bdev(dev);
164 const char *label = data;
165
166 if (!bdev->bd_meta_info || strcmp(label, bdev->bd_meta_info->volname))
167 return 0;
168 return 1;
169}
170
171static dev_t devt_from_partlabel(const char *label)
172{
173 struct device *dev;
174 dev_t devt = 0;
175
176 dev = class_find_device(&block_class, NULL, label, &match_dev_by_label);
177 if (dev) {
178 devt = dev->devt;
179 put_device(dev);
180 }
181
182 return devt;
183}
184
185static dev_t devt_from_devname(const char *name)
186{
187 dev_t devt = 0;
188 int part;
189 char s[32];
190 char *p;
191
192 if (strlen(name) > 31)
193 return 0;
194 strcpy(s, name);
195 for (p = s; *p; p++) {
196 if (*p == '/')
197 *p = '!';
198 }
199
200 devt = blk_lookup_devt(s, 0);
201 if (devt)
202 return devt;
203
204 /*
205 * Try non-existent, but valid partition, which may only exist after
206 * opening the device, like partitioned md devices.
207 */
208 while (p > s && isdigit(p[-1]))
209 p--;
210 if (p == s || !*p || *p == '0')
211 return 0;
212
213 /* try disk name without <part number> */
214 part = simple_strtoul(p, NULL, 10);
215 *p = '\0';
216 devt = blk_lookup_devt(s, part);
217 if (devt)
218 return devt;
219
220 /* try disk name without p<part number> */
221 if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p')
222 return 0;
223 p[-1] = '\0';
224 return blk_lookup_devt(s, part);
225}
226#endif /* CONFIG_BLOCK */
227
228static dev_t devt_from_devnum(const char *name)
229{
230 unsigned maj, min, offset;
231 dev_t devt = 0;
232 char *p, dummy;
233
234 if (sscanf(name, "%u:%u%c", &maj, &min, &dummy) == 2 ||
235 sscanf(name, "%u:%u:%u:%c", &maj, &min, &offset, &dummy) == 3) {
236 devt = MKDEV(maj, min);
237 if (maj != MAJOR(devt) || min != MINOR(devt))
238 return 0;
239 } else {
240 devt = new_decode_dev(simple_strtoul(name, &p, 16));
241 if (*p)
242 return 0;
243 }
244
245 return devt;
246}
247
248/*
249 * Convert a name into device number. We accept the following variants:
250 *
251 * 1) <hex_major><hex_minor> device number in hexadecimal represents itself
252 * no leading 0x, for example b302.
253 * 2) /dev/nfs represents Root_NFS (0xff)
254 * 3) /dev/<disk_name> represents the device number of disk
255 * 4) /dev/<disk_name><decimal> represents the device number
256 * of partition - device number of disk plus the partition number
257 * 5) /dev/<disk_name>p<decimal> - same as the above, that form is
258 * used when disk name of partitioned disk ends on a digit.
259 * 6) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representing the
260 * unique id of a partition if the partition table provides it.
261 * The UUID may be either an EFI/GPT UUID, or refer to an MSDOS
262 * partition using the format SSSSSSSS-PP, where SSSSSSSS is a zero-
263 * filled hex representation of the 32-bit "NT disk signature", and PP
264 * is a zero-filled hex representation of the 1-based partition number.
265 * 7) PARTUUID=<UUID>/PARTNROFF=<int> to select a partition in relation to
266 * a partition with a known unique id.
267 * 8) <major>:<minor> major and minor number of the device separated by
268 * a colon.
269 * 9) PARTLABEL=<name> with name being the GPT partition label.
270 * MSDOS partitions do not support labels!
271 * 10) /dev/cifs represents Root_CIFS (0xfe)
272 *
273 * If name doesn't have fall into the categories above, we return (0,0).
274 * block_class is used to check if something is a disk name. If the disk
275 * name contains slashes, the device name has them replaced with
276 * bangs.
277 */
278dev_t name_to_dev_t(const char *name)
279{
280 if (strcmp(name, "/dev/nfs") == 0)
281 return Root_NFS;
282 if (strcmp(name, "/dev/cifs") == 0)
283 return Root_CIFS;
284 if (strcmp(name, "/dev/ram") == 0)
285 return Root_RAM0;
286#ifdef CONFIG_BLOCK
287 if (strncmp(name, "PARTUUID=", 9) == 0)
288 return devt_from_partuuid(name + 9);
289 if (strncmp(name, "PARTLABEL=", 10) == 0)
290 return devt_from_partlabel(name + 10);
291 if (strncmp(name, "/dev/", 5) == 0)
292 return devt_from_devname(name + 5);
293#endif
294 return devt_from_devnum(name);
295}
296EXPORT_SYMBOL_GPL(name_to_dev_t);
297
298static int __init root_dev_setup(char *line)
299{
300 strlcpy(saved_root_name, line, sizeof(saved_root_name));
301 return 1;
302}
303
304__setup("root=", root_dev_setup);
305
306static int __init rootwait_setup(char *str)
307{
308 if (*str)
309 return 0;
310 root_wait = 1;
311 return 1;
312}
313
314__setup("rootwait", rootwait_setup);
315
316static char * __initdata root_mount_data;
317static int __init root_data_setup(char *str)
318{
319 root_mount_data = str;
320 return 1;
321}
322
323static char * __initdata root_fs_names;
324static int __init fs_names_setup(char *str)
325{
326 root_fs_names = str;
327 return 1;
328}
329
330static unsigned int __initdata root_delay;
331static int __init root_delay_setup(char *str)
332{
333 root_delay = simple_strtoul(str, NULL, 0);
334 return 1;
335}
336
337__setup("rootflags=", root_data_setup);
338__setup("rootfstype=", fs_names_setup);
339__setup("rootdelay=", root_delay_setup);
340
341static void __init get_fs_names(char *page)
342{
343 char *s = page;
344
345 if (root_fs_names) {
346 strcpy(page, root_fs_names);
347 while (*s++) {
348 if (s[-1] == ',')
349 s[-1] = '\0';
350 }
351 } else {
352 int len = get_filesystem_list(page);
353 char *p, *next;
354
355 page[len] = '\0';
356 for (p = page-1; p; p = next) {
357 next = strchr(++p, '\n');
358 if (*p++ != '\t')
359 continue;
360 while ((*s++ = *p++) != '\n')
361 ;
362 s[-1] = '\0';
363 }
364 }
365 *s = '\0';
366}
367
368static int __init do_mount_root(const char *name, const char *fs,
369 const int flags, const void *data)
370{
371 struct super_block *s;
372 struct page *p = NULL;
373 char *data_page = NULL;
374 int ret;
375
376 if (data) {
377 /* init_mount() requires a full page as fifth argument */
378 p = alloc_page(GFP_KERNEL);
379 if (!p)
380 return -ENOMEM;
381 data_page = page_address(p);
382 /* zero-pad. init_mount() will make sure it's terminated */
383 strncpy(data_page, data, PAGE_SIZE);
384 }
385
386 ret = init_mount(name, "/root", fs, flags, data_page);
387 if (ret)
388 goto out;
389
390 init_chdir("/root");
391 s = current->fs->pwd.dentry->d_sb;
392 ROOT_DEV = s->s_dev;
393 printk(KERN_INFO
394 "VFS: Mounted root (%s filesystem)%s on device %u:%u.\n",
395 s->s_type->name,
396 sb_rdonly(s) ? " readonly" : "",
397 MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
398
399out:
400 if (p)
401 put_page(p);
402 return ret;
403}
404
405void __init mount_block_root(char *name, int flags)
406{
407 struct page *page = alloc_page(GFP_KERNEL);
408 char *fs_names = page_address(page);
409 char *p;
410 char b[BDEVNAME_SIZE];
411
412 scnprintf(b, BDEVNAME_SIZE, "unknown-block(%u,%u)",
413 MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
414 get_fs_names(fs_names);
415retry:
416 for (p = fs_names; *p; p += strlen(p)+1) {
417 int err = do_mount_root(name, p, flags, root_mount_data);
418 switch (err) {
419 case 0:
420 goto out;
421 case -EACCES:
422 case -EINVAL:
423 continue;
424 }
425 /*
426 * Allow the user to distinguish between failed sys_open
427 * and bad superblock on root device.
428 * and give them a list of the available devices
429 */
430 printk("VFS: Cannot open root device \"%s\" or %s: error %d\n",
431 root_device_name, b, err);
432 printk("Please append a correct \"root=\" boot option; here are the available partitions:\n");
433
434 printk_all_partitions();
435#ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT
436 printk("DEBUG_BLOCK_EXT_DEVT is enabled, you need to specify "
437 "explicit textual name for \"root=\" boot option.\n");
438#endif
439 panic("VFS: Unable to mount root fs on %s", b);
440 }
441 if (!(flags & SB_RDONLY)) {
442 flags |= SB_RDONLY;
443 goto retry;
444 }
445
446 printk("List of all partitions:\n");
447 printk_all_partitions();
448 printk("No filesystem could mount root, tried: ");
449 for (p = fs_names; *p; p += strlen(p)+1)
450 printk(" %s", p);
451 printk("\n");
452 panic("VFS: Unable to mount root fs on %s", b);
453out:
454 put_page(page);
455}
456
457#ifdef CONFIG_ROOT_NFS
458
459#define NFSROOT_TIMEOUT_MIN 5
460#define NFSROOT_TIMEOUT_MAX 30
461#define NFSROOT_RETRY_MAX 5
462
463static int __init mount_nfs_root(void)
464{
465 char *root_dev, *root_data;
466 unsigned int timeout;
467 int try, err;
468
469 err = nfs_root_data(&root_dev, &root_data);
470 if (err != 0)
471 return 0;
472
473 /*
474 * The server or network may not be ready, so try several
475 * times. Stop after a few tries in case the client wants
476 * to fall back to other boot methods.
477 */
478 timeout = NFSROOT_TIMEOUT_MIN;
479 for (try = 1; ; try++) {
480 err = do_mount_root(root_dev, "nfs",
481 root_mountflags, root_data);
482 if (err == 0)
483 return 1;
484 if (try > NFSROOT_RETRY_MAX)
485 break;
486
487 /* Wait, in case the server refused us immediately */
488 ssleep(timeout);
489 timeout <<= 1;
490 if (timeout > NFSROOT_TIMEOUT_MAX)
491 timeout = NFSROOT_TIMEOUT_MAX;
492 }
493 return 0;
494}
495#endif
496
497#ifdef CONFIG_CIFS_ROOT
498
499extern int cifs_root_data(char **dev, char **opts);
500
501#define CIFSROOT_TIMEOUT_MIN 5
502#define CIFSROOT_TIMEOUT_MAX 30
503#define CIFSROOT_RETRY_MAX 5
504
505static int __init mount_cifs_root(void)
506{
507 char *root_dev, *root_data;
508 unsigned int timeout;
509 int try, err;
510
511 err = cifs_root_data(&root_dev, &root_data);
512 if (err != 0)
513 return 0;
514
515 timeout = CIFSROOT_TIMEOUT_MIN;
516 for (try = 1; ; try++) {
517 err = do_mount_root(root_dev, "cifs", root_mountflags,
518 root_data);
519 if (err == 0)
520 return 1;
521 if (try > CIFSROOT_RETRY_MAX)
522 break;
523
524 ssleep(timeout);
525 timeout <<= 1;
526 if (timeout > CIFSROOT_TIMEOUT_MAX)
527 timeout = CIFSROOT_TIMEOUT_MAX;
528 }
529 return 0;
530}
531#endif
532
533void __init mount_root(void)
534{
535#ifdef CONFIG_ROOT_NFS
536 if (ROOT_DEV == Root_NFS) {
537 if (!mount_nfs_root())
538 printk(KERN_ERR "VFS: Unable to mount root fs via NFS.\n");
539 return;
540 }
541#endif
542#ifdef CONFIG_CIFS_ROOT
543 if (ROOT_DEV == Root_CIFS) {
544 if (!mount_cifs_root())
545 printk(KERN_ERR "VFS: Unable to mount root fs via SMB.\n");
546 return;
547 }
548#endif
549#ifdef CONFIG_BLOCK
550 {
551 int err = create_dev("/dev/root", ROOT_DEV);
552
553 if (err < 0)
554 pr_emerg("Failed to create /dev/root: %d\n", err);
555 mount_block_root("/dev/root", root_mountflags);
556 }
557#endif
558}
559
560/*
561 * Prepare the namespace - decide what/where to mount, load ramdisks, etc.
562 */
563void __init prepare_namespace(void)
564{
565 if (root_delay) {
566 printk(KERN_INFO "Waiting %d sec before mounting root device...\n",
567 root_delay);
568 ssleep(root_delay);
569 }
570
571 /*
572 * wait for the known devices to complete their probing
573 *
574 * Note: this is a potential source of long boot delays.
575 * For example, it is not atypical to wait 5 seconds here
576 * for the touchpad of a laptop to initialize.
577 */
578 wait_for_device_probe();
579
580 md_run_setup();
581
582 if (saved_root_name[0]) {
583 root_device_name = saved_root_name;
584 if (!strncmp(root_device_name, "mtd", 3) ||
585 !strncmp(root_device_name, "ubi", 3)) {
586 mount_block_root(root_device_name, root_mountflags);
587 goto out;
588 }
589 ROOT_DEV = name_to_dev_t(root_device_name);
590 if (strncmp(root_device_name, "/dev/", 5) == 0)
591 root_device_name += 5;
592 }
593
594 if (initrd_load())
595 goto out;
596
597 /* wait for any asynchronous scanning to complete */
598 if ((ROOT_DEV == 0) && root_wait) {
599 printk(KERN_INFO "Waiting for root device %s...\n",
600 saved_root_name);
601 while (driver_probe_done() != 0 ||
602 (ROOT_DEV = name_to_dev_t(saved_root_name)) == 0)
603 msleep(5);
604 async_synchronize_full();
605 }
606
607 mount_root();
608out:
609 devtmpfs_mount();
610 init_mount(".", "/", NULL, MS_MOVE, NULL);
611 init_chroot(".");
612}
613
614static bool is_tmpfs;
615static int rootfs_init_fs_context(struct fs_context *fc)
616{
617 if (IS_ENABLED(CONFIG_TMPFS) && is_tmpfs)
618 return shmem_init_fs_context(fc);
619
620 return ramfs_init_fs_context(fc);
621}
622
623struct file_system_type rootfs_fs_type = {
624 .name = "rootfs",
625 .init_fs_context = rootfs_init_fs_context,
626 .kill_sb = kill_litter_super,
627};
628
629void __init init_rootfs(void)
630{
631 if (IS_ENABLED(CONFIG_TMPFS) && !saved_root_name[0] &&
632 (!root_fs_names || strstr(root_fs_names, "tmpfs")))
633 is_tmpfs = true;
634}