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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/mount.h>
12#include <linux/device.h>
13#include <linux/init.h>
14#include <linux/fs.h>
15#include <linux/initrd.h>
16#include <linux/async.h>
17#include <linux/fs_struct.h>
18#include <linux/slab.h>
19#include <linux/ramfs.h>
20#include <linux/shmem_fs.h>
21#include <linux/ktime.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 saved_root_name[64];
33static int root_wait;
34
35dev_t ROOT_DEV;
36
37static int __init load_ramdisk(char *str)
38{
39 pr_warn("ignoring the deprecated load_ramdisk= option\n");
40 return 1;
41}
42__setup("load_ramdisk=", load_ramdisk);
43
44static int __init readonly(char *str)
45{
46 if (*str)
47 return 0;
48 root_mountflags |= MS_RDONLY;
49 return 1;
50}
51
52static int __init readwrite(char *str)
53{
54 if (*str)
55 return 0;
56 root_mountflags &= ~MS_RDONLY;
57 return 1;
58}
59
60__setup("ro", readonly);
61__setup("rw", readwrite);
62
63static int __init root_dev_setup(char *line)
64{
65 strscpy(saved_root_name, line, sizeof(saved_root_name));
66 return 1;
67}
68
69__setup("root=", root_dev_setup);
70
71static int __init rootwait_setup(char *str)
72{
73 if (*str)
74 return 0;
75 root_wait = -1;
76 return 1;
77}
78
79__setup("rootwait", rootwait_setup);
80
81static int __init rootwait_timeout_setup(char *str)
82{
83 int sec;
84
85 if (kstrtoint(str, 0, &sec) || sec < 0) {
86 pr_warn("ignoring invalid rootwait value\n");
87 goto ignore;
88 }
89
90 if (check_mul_overflow(sec, MSEC_PER_SEC, &root_wait)) {
91 pr_warn("ignoring excessive rootwait value\n");
92 goto ignore;
93 }
94
95 return 1;
96
97ignore:
98 /* Fallback to indefinite wait */
99 root_wait = -1;
100
101 return 1;
102}
103
104__setup("rootwait=", rootwait_timeout_setup);
105
106static char * __initdata root_mount_data;
107static int __init root_data_setup(char *str)
108{
109 root_mount_data = str;
110 return 1;
111}
112
113static char * __initdata root_fs_names;
114static int __init fs_names_setup(char *str)
115{
116 root_fs_names = str;
117 return 1;
118}
119
120static unsigned int __initdata root_delay;
121static int __init root_delay_setup(char *str)
122{
123 root_delay = simple_strtoul(str, NULL, 0);
124 return 1;
125}
126
127__setup("rootflags=", root_data_setup);
128__setup("rootfstype=", fs_names_setup);
129__setup("rootdelay=", root_delay_setup);
130
131/* This can return zero length strings. Caller should check */
132static int __init split_fs_names(char *page, size_t size)
133{
134 int count = 1;
135 char *p = page;
136
137 strscpy(p, root_fs_names, size);
138 while (*p++) {
139 if (p[-1] == ',') {
140 p[-1] = '\0';
141 count++;
142 }
143 }
144
145 return count;
146}
147
148static int __init do_mount_root(const char *name, const char *fs,
149 const int flags, const void *data)
150{
151 struct super_block *s;
152 struct page *p = NULL;
153 char *data_page = NULL;
154 int ret;
155
156 if (data) {
157 /* init_mount() requires a full page as fifth argument */
158 p = alloc_page(GFP_KERNEL);
159 if (!p)
160 return -ENOMEM;
161 data_page = page_address(p);
162 /* zero-pad. init_mount() will make sure it's terminated */
163 strncpy(data_page, data, PAGE_SIZE);
164 }
165
166 ret = init_mount(name, "/root", fs, flags, data_page);
167 if (ret)
168 goto out;
169
170 init_chdir("/root");
171 s = current->fs->pwd.dentry->d_sb;
172 ROOT_DEV = s->s_dev;
173 printk(KERN_INFO
174 "VFS: Mounted root (%s filesystem)%s on device %u:%u.\n",
175 s->s_type->name,
176 sb_rdonly(s) ? " readonly" : "",
177 MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
178
179out:
180 if (p)
181 put_page(p);
182 return ret;
183}
184
185void __init mount_root_generic(char *name, char *pretty_name, int flags)
186{
187 struct page *page = alloc_page(GFP_KERNEL);
188 char *fs_names = page_address(page);
189 char *p;
190 char b[BDEVNAME_SIZE];
191 int num_fs, i;
192
193 scnprintf(b, BDEVNAME_SIZE, "unknown-block(%u,%u)",
194 MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
195 if (root_fs_names)
196 num_fs = split_fs_names(fs_names, PAGE_SIZE);
197 else
198 num_fs = list_bdev_fs_names(fs_names, PAGE_SIZE);
199retry:
200 for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1) {
201 int err;
202
203 if (!*p)
204 continue;
205 err = do_mount_root(name, p, flags, root_mount_data);
206 switch (err) {
207 case 0:
208 goto out;
209 case -EACCES:
210 case -EINVAL:
211 continue;
212 }
213 /*
214 * Allow the user to distinguish between failed sys_open
215 * and bad superblock on root device.
216 * and give them a list of the available devices
217 */
218 printk("VFS: Cannot open root device \"%s\" or %s: error %d\n",
219 pretty_name, b, err);
220 printk("Please append a correct \"root=\" boot option; here are the available partitions:\n");
221 printk_all_partitions();
222
223 if (root_fs_names)
224 num_fs = list_bdev_fs_names(fs_names, PAGE_SIZE);
225 if (!num_fs)
226 pr_err("Can't find any bdev filesystem to be used for mount!\n");
227 else {
228 pr_err("List of all bdev filesystems:\n");
229 for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1)
230 pr_err(" %s", p);
231 pr_err("\n");
232 }
233
234 panic("VFS: Unable to mount root fs on %s", b);
235 }
236 if (!(flags & SB_RDONLY)) {
237 flags |= SB_RDONLY;
238 goto retry;
239 }
240
241 printk("List of all partitions:\n");
242 printk_all_partitions();
243 printk("No filesystem could mount root, tried: ");
244 for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1)
245 printk(" %s", p);
246 printk("\n");
247 panic("VFS: Unable to mount root fs on \"%s\" or %s", pretty_name, b);
248out:
249 put_page(page);
250}
251
252#ifdef CONFIG_ROOT_NFS
253
254#define NFSROOT_TIMEOUT_MIN 5
255#define NFSROOT_TIMEOUT_MAX 30
256#define NFSROOT_RETRY_MAX 5
257
258static void __init mount_nfs_root(void)
259{
260 char *root_dev, *root_data;
261 unsigned int timeout;
262 int try;
263
264 if (nfs_root_data(&root_dev, &root_data))
265 goto fail;
266
267 /*
268 * The server or network may not be ready, so try several
269 * times. Stop after a few tries in case the client wants
270 * to fall back to other boot methods.
271 */
272 timeout = NFSROOT_TIMEOUT_MIN;
273 for (try = 1; ; try++) {
274 if (!do_mount_root(root_dev, "nfs", root_mountflags, root_data))
275 return;
276 if (try > NFSROOT_RETRY_MAX)
277 break;
278
279 /* Wait, in case the server refused us immediately */
280 ssleep(timeout);
281 timeout <<= 1;
282 if (timeout > NFSROOT_TIMEOUT_MAX)
283 timeout = NFSROOT_TIMEOUT_MAX;
284 }
285fail:
286 pr_err("VFS: Unable to mount root fs via NFS.\n");
287}
288#else
289static inline void mount_nfs_root(void)
290{
291}
292#endif /* CONFIG_ROOT_NFS */
293
294#ifdef CONFIG_CIFS_ROOT
295
296#define CIFSROOT_TIMEOUT_MIN 5
297#define CIFSROOT_TIMEOUT_MAX 30
298#define CIFSROOT_RETRY_MAX 5
299
300static void __init mount_cifs_root(void)
301{
302 char *root_dev, *root_data;
303 unsigned int timeout;
304 int try;
305
306 if (cifs_root_data(&root_dev, &root_data))
307 goto fail;
308
309 timeout = CIFSROOT_TIMEOUT_MIN;
310 for (try = 1; ; try++) {
311 if (!do_mount_root(root_dev, "cifs", root_mountflags,
312 root_data))
313 return;
314 if (try > CIFSROOT_RETRY_MAX)
315 break;
316
317 ssleep(timeout);
318 timeout <<= 1;
319 if (timeout > CIFSROOT_TIMEOUT_MAX)
320 timeout = CIFSROOT_TIMEOUT_MAX;
321 }
322fail:
323 pr_err("VFS: Unable to mount root fs via SMB.\n");
324}
325#else
326static inline void mount_cifs_root(void)
327{
328}
329#endif /* CONFIG_CIFS_ROOT */
330
331static bool __init fs_is_nodev(char *fstype)
332{
333 struct file_system_type *fs = get_fs_type(fstype);
334 bool ret = false;
335
336 if (fs) {
337 ret = !(fs->fs_flags & FS_REQUIRES_DEV);
338 put_filesystem(fs);
339 }
340
341 return ret;
342}
343
344static int __init mount_nodev_root(char *root_device_name)
345{
346 char *fs_names, *fstype;
347 int err = -EINVAL;
348 int num_fs, i;
349
350 fs_names = (void *)__get_free_page(GFP_KERNEL);
351 if (!fs_names)
352 return -EINVAL;
353 num_fs = split_fs_names(fs_names, PAGE_SIZE);
354
355 for (i = 0, fstype = fs_names; i < num_fs;
356 i++, fstype += strlen(fstype) + 1) {
357 if (!*fstype)
358 continue;
359 if (!fs_is_nodev(fstype))
360 continue;
361 err = do_mount_root(root_device_name, fstype, root_mountflags,
362 root_mount_data);
363 if (!err)
364 break;
365 }
366
367 free_page((unsigned long)fs_names);
368 return err;
369}
370
371#ifdef CONFIG_BLOCK
372static void __init mount_block_root(char *root_device_name)
373{
374 int err = create_dev("/dev/root", ROOT_DEV);
375
376 if (err < 0)
377 pr_emerg("Failed to create /dev/root: %d\n", err);
378 mount_root_generic("/dev/root", root_device_name, root_mountflags);
379}
380#else
381static inline void mount_block_root(char *root_device_name)
382{
383}
384#endif /* CONFIG_BLOCK */
385
386void __init mount_root(char *root_device_name)
387{
388 switch (ROOT_DEV) {
389 case Root_NFS:
390 mount_nfs_root();
391 break;
392 case Root_CIFS:
393 mount_cifs_root();
394 break;
395 case Root_Generic:
396 mount_root_generic(root_device_name, root_device_name,
397 root_mountflags);
398 break;
399 case 0:
400 if (root_device_name && root_fs_names &&
401 mount_nodev_root(root_device_name) == 0)
402 break;
403 fallthrough;
404 default:
405 mount_block_root(root_device_name);
406 break;
407 }
408}
409
410/* wait for any asynchronous scanning to complete */
411static void __init wait_for_root(char *root_device_name)
412{
413 ktime_t end;
414
415 if (ROOT_DEV != 0)
416 return;
417
418 pr_info("Waiting for root device %s...\n", root_device_name);
419
420 end = ktime_add_ms(ktime_get_raw(), root_wait);
421
422 while (!driver_probe_done() ||
423 early_lookup_bdev(root_device_name, &ROOT_DEV) < 0) {
424 msleep(5);
425 if (root_wait > 0 && ktime_after(ktime_get_raw(), end))
426 break;
427 }
428
429 async_synchronize_full();
430
431}
432
433static dev_t __init parse_root_device(char *root_device_name)
434{
435 int error;
436 dev_t dev;
437
438 if (!strncmp(root_device_name, "mtd", 3) ||
439 !strncmp(root_device_name, "ubi", 3))
440 return Root_Generic;
441 if (strcmp(root_device_name, "/dev/nfs") == 0)
442 return Root_NFS;
443 if (strcmp(root_device_name, "/dev/cifs") == 0)
444 return Root_CIFS;
445 if (strcmp(root_device_name, "/dev/ram") == 0)
446 return Root_RAM0;
447
448 error = early_lookup_bdev(root_device_name, &dev);
449 if (error) {
450 if (error == -EINVAL && root_wait) {
451 pr_err("Disabling rootwait; root= is invalid.\n");
452 root_wait = 0;
453 }
454 return 0;
455 }
456 return dev;
457}
458
459/*
460 * Prepare the namespace - decide what/where to mount, load ramdisks, etc.
461 */
462void __init prepare_namespace(void)
463{
464 if (root_delay) {
465 printk(KERN_INFO "Waiting %d sec before mounting root device...\n",
466 root_delay);
467 ssleep(root_delay);
468 }
469
470 /*
471 * wait for the known devices to complete their probing
472 *
473 * Note: this is a potential source of long boot delays.
474 * For example, it is not atypical to wait 5 seconds here
475 * for the touchpad of a laptop to initialize.
476 */
477 wait_for_device_probe();
478
479 md_run_setup();
480
481 if (saved_root_name[0])
482 ROOT_DEV = parse_root_device(saved_root_name);
483
484 if (initrd_load(saved_root_name))
485 goto out;
486
487 if (root_wait)
488 wait_for_root(saved_root_name);
489 mount_root(saved_root_name);
490out:
491 devtmpfs_mount();
492 init_mount(".", "/", NULL, MS_MOVE, NULL);
493 init_chroot(".");
494}
495
496static bool is_tmpfs;
497static int rootfs_init_fs_context(struct fs_context *fc)
498{
499 if (IS_ENABLED(CONFIG_TMPFS) && is_tmpfs)
500 return shmem_init_fs_context(fc);
501
502 return ramfs_init_fs_context(fc);
503}
504
505struct file_system_type rootfs_fs_type = {
506 .name = "rootfs",
507 .init_fs_context = rootfs_init_fs_context,
508 .kill_sb = kill_litter_super,
509};
510
511void __init init_rootfs(void)
512{
513 if (IS_ENABLED(CONFIG_TMPFS)) {
514 if (!saved_root_name[0] && !root_fs_names)
515 is_tmpfs = true;
516 else if (root_fs_names && !!strstr(root_fs_names, "tmpfs"))
517 is_tmpfs = true;
518 }
519}
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#include <linux/ramfs.h>
30#include <linux/shmem_fs.h>
31
32#include <linux/nfs_fs.h>
33#include <linux/nfs_fs_sb.h>
34#include <linux/nfs_mount.h>
35
36#include "do_mounts.h"
37
38int __initdata rd_doload; /* 1 = load RAM disk, 0 = don't load */
39
40int root_mountflags = MS_RDONLY | MS_SILENT;
41static char * __initdata root_device_name;
42static char __initdata saved_root_name[64];
43static int root_wait;
44
45dev_t ROOT_DEV;
46
47static int __init load_ramdisk(char *str)
48{
49 rd_doload = simple_strtol(str,NULL,0) & 3;
50 return 1;
51}
52__setup("load_ramdisk=", load_ramdisk);
53
54static int __init readonly(char *str)
55{
56 if (*str)
57 return 0;
58 root_mountflags |= MS_RDONLY;
59 return 1;
60}
61
62static int __init readwrite(char *str)
63{
64 if (*str)
65 return 0;
66 root_mountflags &= ~MS_RDONLY;
67 return 1;
68}
69
70__setup("ro", readonly);
71__setup("rw", readwrite);
72
73#ifdef CONFIG_BLOCK
74struct uuidcmp {
75 const char *uuid;
76 int len;
77};
78
79/**
80 * match_dev_by_uuid - callback for finding a partition using its uuid
81 * @dev: device passed in by the caller
82 * @data: opaque pointer to the desired struct uuidcmp to match
83 *
84 * Returns 1 if the device matches, and 0 otherwise.
85 */
86static int match_dev_by_uuid(struct device *dev, const void *data)
87{
88 const struct uuidcmp *cmp = data;
89 struct hd_struct *part = dev_to_part(dev);
90
91 if (!part->info)
92 goto no_match;
93
94 if (strncasecmp(cmp->uuid, part->info->uuid, cmp->len))
95 goto no_match;
96
97 return 1;
98no_match:
99 return 0;
100}
101
102
103/**
104 * devt_from_partuuid - looks up the dev_t of a partition by its UUID
105 * @uuid_str: char array containing ascii UUID
106 *
107 * The function will return the first partition which contains a matching
108 * UUID value in its partition_meta_info struct. This does not search
109 * by filesystem UUIDs.
110 *
111 * If @uuid_str is followed by a "/PARTNROFF=%d", then the number will be
112 * extracted and used as an offset from the partition identified by the UUID.
113 *
114 * Returns the matching dev_t on success or 0 on failure.
115 */
116static dev_t devt_from_partuuid(const char *uuid_str)
117{
118 dev_t res = 0;
119 struct uuidcmp cmp;
120 struct device *dev = NULL;
121 struct gendisk *disk;
122 struct hd_struct *part;
123 int offset = 0;
124 bool clear_root_wait = false;
125 char *slash;
126
127 cmp.uuid = uuid_str;
128
129 slash = strchr(uuid_str, '/');
130 /* Check for optional partition number offset attributes. */
131 if (slash) {
132 char c = 0;
133 /* Explicitly fail on poor PARTUUID syntax. */
134 if (sscanf(slash + 1,
135 "PARTNROFF=%d%c", &offset, &c) != 1) {
136 clear_root_wait = true;
137 goto done;
138 }
139 cmp.len = slash - uuid_str;
140 } else {
141 cmp.len = strlen(uuid_str);
142 }
143
144 if (!cmp.len) {
145 clear_root_wait = true;
146 goto done;
147 }
148
149 dev = class_find_device(&block_class, NULL, &cmp,
150 &match_dev_by_uuid);
151 if (!dev)
152 goto done;
153
154 res = dev->devt;
155
156 /* Attempt to find the partition by offset. */
157 if (!offset)
158 goto no_offset;
159
160 res = 0;
161 disk = part_to_disk(dev_to_part(dev));
162 part = disk_get_part(disk, dev_to_part(dev)->partno + offset);
163 if (part) {
164 res = part_devt(part);
165 put_device(part_to_dev(part));
166 }
167
168no_offset:
169 put_device(dev);
170done:
171 if (clear_root_wait) {
172 pr_err("VFS: PARTUUID= is invalid.\n"
173 "Expected PARTUUID=<valid-uuid-id>[/PARTNROFF=%%d]\n");
174 if (root_wait)
175 pr_err("Disabling rootwait; root= is invalid.\n");
176 root_wait = 0;
177 }
178 return res;
179}
180#endif
181
182/*
183 * Convert a name into device number. We accept the following variants:
184 *
185 * 1) <hex_major><hex_minor> device number in hexadecimal represents itself
186 * no leading 0x, for example b302.
187 * 2) /dev/nfs represents Root_NFS (0xff)
188 * 3) /dev/<disk_name> represents the device number of disk
189 * 4) /dev/<disk_name><decimal> represents the device number
190 * of partition - device number of disk plus the partition number
191 * 5) /dev/<disk_name>p<decimal> - same as the above, that form is
192 * used when disk name of partitioned disk ends on a digit.
193 * 6) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representing the
194 * unique id of a partition if the partition table provides it.
195 * The UUID may be either an EFI/GPT UUID, or refer to an MSDOS
196 * partition using the format SSSSSSSS-PP, where SSSSSSSS is a zero-
197 * filled hex representation of the 32-bit "NT disk signature", and PP
198 * is a zero-filled hex representation of the 1-based partition number.
199 * 7) PARTUUID=<UUID>/PARTNROFF=<int> to select a partition in relation to
200 * a partition with a known unique id.
201 * 8) <major>:<minor> major and minor number of the device separated by
202 * a colon.
203 *
204 * If name doesn't have fall into the categories above, we return (0,0).
205 * block_class is used to check if something is a disk name. If the disk
206 * name contains slashes, the device name has them replaced with
207 * bangs.
208 */
209
210dev_t name_to_dev_t(const char *name)
211{
212 char s[32];
213 char *p;
214 dev_t res = 0;
215 int part;
216
217#ifdef CONFIG_BLOCK
218 if (strncmp(name, "PARTUUID=", 9) == 0) {
219 name += 9;
220 res = devt_from_partuuid(name);
221 if (!res)
222 goto fail;
223 goto done;
224 }
225#endif
226
227 if (strncmp(name, "/dev/", 5) != 0) {
228 unsigned maj, min, offset;
229 char dummy;
230
231 if ((sscanf(name, "%u:%u%c", &maj, &min, &dummy) == 2) ||
232 (sscanf(name, "%u:%u:%u:%c", &maj, &min, &offset, &dummy) == 3)) {
233 res = MKDEV(maj, min);
234 if (maj != MAJOR(res) || min != MINOR(res))
235 goto fail;
236 } else {
237 res = new_decode_dev(simple_strtoul(name, &p, 16));
238 if (*p)
239 goto fail;
240 }
241 goto done;
242 }
243
244 name += 5;
245 res = Root_NFS;
246 if (strcmp(name, "nfs") == 0)
247 goto done;
248 res = Root_RAM0;
249 if (strcmp(name, "ram") == 0)
250 goto done;
251
252 if (strlen(name) > 31)
253 goto fail;
254 strcpy(s, name);
255 for (p = s; *p; p++)
256 if (*p == '/')
257 *p = '!';
258 res = blk_lookup_devt(s, 0);
259 if (res)
260 goto done;
261
262 /*
263 * try non-existent, but valid partition, which may only exist
264 * after revalidating the disk, like partitioned md devices
265 */
266 while (p > s && isdigit(p[-1]))
267 p--;
268 if (p == s || !*p || *p == '0')
269 goto fail;
270
271 /* try disk name without <part number> */
272 part = simple_strtoul(p, NULL, 10);
273 *p = '\0';
274 res = blk_lookup_devt(s, part);
275 if (res)
276 goto done;
277
278 /* try disk name without p<part number> */
279 if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p')
280 goto fail;
281 p[-1] = '\0';
282 res = blk_lookup_devt(s, part);
283 if (res)
284 goto done;
285
286fail:
287 return 0;
288done:
289 return res;
290}
291EXPORT_SYMBOL_GPL(name_to_dev_t);
292
293static int __init root_dev_setup(char *line)
294{
295 strlcpy(saved_root_name, line, sizeof(saved_root_name));
296 return 1;
297}
298
299__setup("root=", root_dev_setup);
300
301static int __init rootwait_setup(char *str)
302{
303 if (*str)
304 return 0;
305 root_wait = 1;
306 return 1;
307}
308
309__setup("rootwait", rootwait_setup);
310
311static char * __initdata root_mount_data;
312static int __init root_data_setup(char *str)
313{
314 root_mount_data = str;
315 return 1;
316}
317
318static char * __initdata root_fs_names;
319static int __init fs_names_setup(char *str)
320{
321 root_fs_names = str;
322 return 1;
323}
324
325static unsigned int __initdata root_delay;
326static int __init root_delay_setup(char *str)
327{
328 root_delay = simple_strtoul(str, NULL, 0);
329 return 1;
330}
331
332__setup("rootflags=", root_data_setup);
333__setup("rootfstype=", fs_names_setup);
334__setup("rootdelay=", root_delay_setup);
335
336static void __init get_fs_names(char *page)
337{
338 char *s = page;
339
340 if (root_fs_names) {
341 strcpy(page, root_fs_names);
342 while (*s++) {
343 if (s[-1] == ',')
344 s[-1] = '\0';
345 }
346 } else {
347 int len = get_filesystem_list(page);
348 char *p, *next;
349
350 page[len] = '\0';
351 for (p = page-1; p; p = next) {
352 next = strchr(++p, '\n');
353 if (*p++ != '\t')
354 continue;
355 while ((*s++ = *p++) != '\n')
356 ;
357 s[-1] = '\0';
358 }
359 }
360 *s = '\0';
361}
362
363static int __init do_mount_root(char *name, char *fs, int flags, void *data)
364{
365 struct super_block *s;
366 int err = sys_mount(name, "/root", fs, flags, data);
367 if (err)
368 return err;
369
370 sys_chdir("/root");
371 s = current->fs->pwd.dentry->d_sb;
372 ROOT_DEV = s->s_dev;
373 printk(KERN_INFO
374 "VFS: Mounted root (%s filesystem)%s on device %u:%u.\n",
375 s->s_type->name,
376 s->s_flags & MS_RDONLY ? " readonly" : "",
377 MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
378 return 0;
379}
380
381void __init mount_block_root(char *name, int flags)
382{
383 struct page *page = alloc_page(GFP_KERNEL |
384 __GFP_NOTRACK_FALSE_POSITIVE);
385 char *fs_names = page_address(page);
386 char *p;
387#ifdef CONFIG_BLOCK
388 char b[BDEVNAME_SIZE];
389#else
390 const char *b = name;
391#endif
392
393 get_fs_names(fs_names);
394retry:
395 for (p = fs_names; *p; p += strlen(p)+1) {
396 int err = do_mount_root(name, p, flags, root_mount_data);
397 switch (err) {
398 case 0:
399 goto out;
400 case -EACCES:
401 case -EINVAL:
402 continue;
403 }
404 /*
405 * Allow the user to distinguish between failed sys_open
406 * and bad superblock on root device.
407 * and give them a list of the available devices
408 */
409#ifdef CONFIG_BLOCK
410 __bdevname(ROOT_DEV, b);
411#endif
412 printk("VFS: Cannot open root device \"%s\" or %s: error %d\n",
413 root_device_name, b, err);
414 printk("Please append a correct \"root=\" boot option; here are the available partitions:\n");
415
416 printk_all_partitions();
417#ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT
418 printk("DEBUG_BLOCK_EXT_DEVT is enabled, you need to specify "
419 "explicit textual name for \"root=\" boot option.\n");
420#endif
421 panic("VFS: Unable to mount root fs on %s", b);
422 }
423 if (!(flags & MS_RDONLY)) {
424 flags |= MS_RDONLY;
425 goto retry;
426 }
427
428 printk("List of all partitions:\n");
429 printk_all_partitions();
430 printk("No filesystem could mount root, tried: ");
431 for (p = fs_names; *p; p += strlen(p)+1)
432 printk(" %s", p);
433 printk("\n");
434#ifdef CONFIG_BLOCK
435 __bdevname(ROOT_DEV, b);
436#endif
437 panic("VFS: Unable to mount root fs on %s", b);
438out:
439 put_page(page);
440}
441
442#ifdef CONFIG_ROOT_NFS
443
444#define NFSROOT_TIMEOUT_MIN 5
445#define NFSROOT_TIMEOUT_MAX 30
446#define NFSROOT_RETRY_MAX 5
447
448static int __init mount_nfs_root(void)
449{
450 char *root_dev, *root_data;
451 unsigned int timeout;
452 int try, err;
453
454 err = nfs_root_data(&root_dev, &root_data);
455 if (err != 0)
456 return 0;
457
458 /*
459 * The server or network may not be ready, so try several
460 * times. Stop after a few tries in case the client wants
461 * to fall back to other boot methods.
462 */
463 timeout = NFSROOT_TIMEOUT_MIN;
464 for (try = 1; ; try++) {
465 err = do_mount_root(root_dev, "nfs",
466 root_mountflags, root_data);
467 if (err == 0)
468 return 1;
469 if (try > NFSROOT_RETRY_MAX)
470 break;
471
472 /* Wait, in case the server refused us immediately */
473 ssleep(timeout);
474 timeout <<= 1;
475 if (timeout > NFSROOT_TIMEOUT_MAX)
476 timeout = NFSROOT_TIMEOUT_MAX;
477 }
478 return 0;
479}
480#endif
481
482#if defined(CONFIG_BLK_DEV_RAM) || defined(CONFIG_BLK_DEV_FD)
483void __init change_floppy(char *fmt, ...)
484{
485 struct termios termios;
486 char buf[80];
487 char c;
488 int fd;
489 va_list args;
490 va_start(args, fmt);
491 vsprintf(buf, fmt, args);
492 va_end(args);
493 fd = sys_open("/dev/root", O_RDWR | O_NDELAY, 0);
494 if (fd >= 0) {
495 sys_ioctl(fd, FDEJECT, 0);
496 sys_close(fd);
497 }
498 printk(KERN_NOTICE "VFS: Insert %s and press ENTER\n", buf);
499 fd = sys_open("/dev/console", O_RDWR, 0);
500 if (fd >= 0) {
501 sys_ioctl(fd, TCGETS, (long)&termios);
502 termios.c_lflag &= ~ICANON;
503 sys_ioctl(fd, TCSETSF, (long)&termios);
504 sys_read(fd, &c, 1);
505 termios.c_lflag |= ICANON;
506 sys_ioctl(fd, TCSETSF, (long)&termios);
507 sys_close(fd);
508 }
509}
510#endif
511
512void __init mount_root(void)
513{
514#ifdef CONFIG_ROOT_NFS
515 if (ROOT_DEV == Root_NFS) {
516 if (mount_nfs_root())
517 return;
518
519 printk(KERN_ERR "VFS: Unable to mount root fs via NFS, trying floppy.\n");
520 ROOT_DEV = Root_FD0;
521 }
522#endif
523#ifdef CONFIG_BLK_DEV_FD
524 if (MAJOR(ROOT_DEV) == FLOPPY_MAJOR) {
525 /* rd_doload is 2 for a dual initrd/ramload setup */
526 if (rd_doload==2) {
527 if (rd_load_disk(1)) {
528 ROOT_DEV = Root_RAM1;
529 root_device_name = NULL;
530 }
531 } else
532 change_floppy("root floppy");
533 }
534#endif
535#ifdef CONFIG_BLOCK
536 {
537 int err = create_dev("/dev/root", ROOT_DEV);
538
539 if (err < 0)
540 pr_emerg("Failed to create /dev/root: %d\n", err);
541 mount_block_root("/dev/root", root_mountflags);
542 }
543#endif
544}
545
546/*
547 * Prepare the namespace - decide what/where to mount, load ramdisks, etc.
548 */
549void __init prepare_namespace(void)
550{
551 int is_floppy;
552
553 if (root_delay) {
554 printk(KERN_INFO "Waiting %d sec before mounting root device...\n",
555 root_delay);
556 ssleep(root_delay);
557 }
558
559 /*
560 * wait for the known devices to complete their probing
561 *
562 * Note: this is a potential source of long boot delays.
563 * For example, it is not atypical to wait 5 seconds here
564 * for the touchpad of a laptop to initialize.
565 */
566 wait_for_device_probe();
567
568 md_run_setup();
569
570 if (saved_root_name[0]) {
571 root_device_name = saved_root_name;
572 if (!strncmp(root_device_name, "mtd", 3) ||
573 !strncmp(root_device_name, "ubi", 3)) {
574 mount_block_root(root_device_name, root_mountflags);
575 goto out;
576 }
577 ROOT_DEV = name_to_dev_t(root_device_name);
578 if (strncmp(root_device_name, "/dev/", 5) == 0)
579 root_device_name += 5;
580 }
581
582 if (initrd_load())
583 goto out;
584
585 /* wait for any asynchronous scanning to complete */
586 if ((ROOT_DEV == 0) && root_wait) {
587 printk(KERN_INFO "Waiting for root device %s...\n",
588 saved_root_name);
589 while (driver_probe_done() != 0 ||
590 (ROOT_DEV = name_to_dev_t(saved_root_name)) == 0)
591 msleep(5);
592 async_synchronize_full();
593 }
594
595 is_floppy = MAJOR(ROOT_DEV) == FLOPPY_MAJOR;
596
597 if (is_floppy && rd_doload && rd_load_disk(0))
598 ROOT_DEV = Root_RAM0;
599
600 mount_root();
601out:
602 devtmpfs_mount("dev");
603 sys_mount(".", "/", NULL, MS_MOVE, NULL);
604 sys_chroot(".");
605}
606
607static bool is_tmpfs;
608static struct dentry *rootfs_mount(struct file_system_type *fs_type,
609 int flags, const char *dev_name, void *data)
610{
611 static unsigned long once;
612 void *fill = ramfs_fill_super;
613
614 if (test_and_set_bit(0, &once))
615 return ERR_PTR(-ENODEV);
616
617 if (IS_ENABLED(CONFIG_TMPFS) && is_tmpfs)
618 fill = shmem_fill_super;
619
620 return mount_nodev(fs_type, flags, data, fill);
621}
622
623static struct file_system_type rootfs_fs_type = {
624 .name = "rootfs",
625 .mount = rootfs_mount,
626 .kill_sb = kill_litter_super,
627};
628
629int __init init_rootfs(void)
630{
631 int err = register_filesystem(&rootfs_fs_type);
632
633 if (err)
634 return err;
635
636 if (IS_ENABLED(CONFIG_TMPFS) && !saved_root_name[0] &&
637 (!root_fs_names || strstr(root_fs_names, "tmpfs"))) {
638 err = shmem_init();
639 is_tmpfs = true;
640 } else {
641 err = init_ramfs_fs();
642 }
643
644 if (err)
645 unregister_filesystem(&rootfs_fs_type);
646
647 return err;
648}