1#include <linux/module.h>
2#include <linux/sched.h>
3#include <linux/ctype.h>
4#include <linux/fd.h>
5#include <linux/tty.h>
6#include <linux/suspend.h>
7#include <linux/root_dev.h>
8#include <linux/security.h>
9#include <linux/delay.h>
10#include <linux/genhd.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
22#include <linux/nfs_fs.h>
23#include <linux/nfs_fs_sb.h>
24#include <linux/nfs_mount.h>
25#include <uapi/linux/mount.h>
26
27#include "do_mounts.h"
28
29int __initdata rd_doload; /* 1 = load RAM disk, 0 = don't load */
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 rd_doload = simple_strtol(str,NULL,0) & 3;
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 const struct uuidcmp *cmp = data;
80 struct hd_struct *part = dev_to_part(dev);
81
82 if (!part->info)
83 goto no_match;
84
85 if (strncasecmp(cmp->uuid, part->info->uuid, cmp->len))
86 goto no_match;
87
88 return 1;
89no_match:
90 return 0;
91}
92
93
94/**
95 * devt_from_partuuid - looks up the dev_t of a partition by its UUID
96 * @uuid_str: char array containing ascii UUID
97 *
98 * The function will return the first partition which contains a matching
99 * UUID value in its partition_meta_info struct. This does not search
100 * by filesystem UUIDs.
101 *
102 * If @uuid_str is followed by a "/PARTNROFF=%d", then the number will be
103 * extracted and used as an offset from the partition identified by the UUID.
104 *
105 * Returns the matching dev_t on success or 0 on failure.
106 */
107static dev_t devt_from_partuuid(const char *uuid_str)
108{
109 dev_t res = 0;
110 struct uuidcmp cmp;
111 struct device *dev = NULL;
112 struct gendisk *disk;
113 struct hd_struct *part;
114 int offset = 0;
115 bool clear_root_wait = false;
116 char *slash;
117
118 cmp.uuid = uuid_str;
119
120 slash = strchr(uuid_str, '/');
121 /* Check for optional partition number offset attributes. */
122 if (slash) {
123 char c = 0;
124 /* Explicitly fail on poor PARTUUID syntax. */
125 if (sscanf(slash + 1,
126 "PARTNROFF=%d%c", &offset, &c) != 1) {
127 clear_root_wait = true;
128 goto done;
129 }
130 cmp.len = slash - uuid_str;
131 } else {
132 cmp.len = strlen(uuid_str);
133 }
134
135 if (!cmp.len) {
136 clear_root_wait = true;
137 goto done;
138 }
139
140 dev = class_find_device(&block_class, NULL, &cmp,
141 &match_dev_by_uuid);
142 if (!dev)
143 goto done;
144
145 res = dev->devt;
146
147 /* Attempt to find the partition by offset. */
148 if (!offset)
149 goto no_offset;
150
151 res = 0;
152 disk = part_to_disk(dev_to_part(dev));
153 part = disk_get_part(disk, dev_to_part(dev)->partno + offset);
154 if (part) {
155 res = part_devt(part);
156 put_device(part_to_dev(part));
157 }
158
159no_offset:
160 put_device(dev);
161done:
162 if (clear_root_wait) {
163 pr_err("VFS: PARTUUID= is invalid.\n"
164 "Expected PARTUUID=<valid-uuid-id>[/PARTNROFF=%%d]\n");
165 if (root_wait)
166 pr_err("Disabling rootwait; root= is invalid.\n");
167 root_wait = 0;
168 }
169 return res;
170}
171
172/**
173 * match_dev_by_label - callback for finding a partition using its label
174 * @dev: device passed in by the caller
175 * @data: opaque pointer to the label to match
176 *
177 * Returns 1 if the device matches, and 0 otherwise.
178 */
179static int match_dev_by_label(struct device *dev, const void *data)
180{
181 const char *label = data;
182 struct hd_struct *part = dev_to_part(dev);
183
184 if (part->info && !strcmp(label, part->info->volname))
185 return 1;
186
187 return 0;
188}
189#endif
190
191/*
192 * Convert a name into device number. We accept the following variants:
193 *
194 * 1) <hex_major><hex_minor> device number in hexadecimal represents itself
195 * no leading 0x, for example b302.
196 * 2) /dev/nfs represents Root_NFS (0xff)
197 * 3) /dev/<disk_name> represents the device number of disk
198 * 4) /dev/<disk_name><decimal> represents the device number
199 * of partition - device number of disk plus the partition number
200 * 5) /dev/<disk_name>p<decimal> - same as the above, that form is
201 * used when disk name of partitioned disk ends on a digit.
202 * 6) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representing the
203 * unique id of a partition if the partition table provides it.
204 * The UUID may be either an EFI/GPT UUID, or refer to an MSDOS
205 * partition using the format SSSSSSSS-PP, where SSSSSSSS is a zero-
206 * filled hex representation of the 32-bit "NT disk signature", and PP
207 * is a zero-filled hex representation of the 1-based partition number.
208 * 7) PARTUUID=<UUID>/PARTNROFF=<int> to select a partition in relation to
209 * a partition with a known unique id.
210 * 8) <major>:<minor> major and minor number of the device separated by
211 * a colon.
212 * 9) PARTLABEL=<name> with name being the GPT partition label.
213 * MSDOS partitions do not support labels!
214 *
215 * If name doesn't have fall into the categories above, we return (0,0).
216 * block_class is used to check if something is a disk name. If the disk
217 * name contains slashes, the device name has them replaced with
218 * bangs.
219 */
220
221dev_t name_to_dev_t(const char *name)
222{
223 char s[32];
224 char *p;
225 dev_t res = 0;
226 int part;
227
228#ifdef CONFIG_BLOCK
229 if (strncmp(name, "PARTUUID=", 9) == 0) {
230 name += 9;
231 res = devt_from_partuuid(name);
232 if (!res)
233 goto fail;
234 goto done;
235 } else if (strncmp(name, "PARTLABEL=", 10) == 0) {
236 struct device *dev;
237
238 dev = class_find_device(&block_class, NULL, name + 10,
239 &match_dev_by_label);
240 if (!dev)
241 goto fail;
242
243 res = dev->devt;
244 put_device(dev);
245 goto done;
246 }
247#endif
248
249 if (strncmp(name, "/dev/", 5) != 0) {
250 unsigned maj, min, offset;
251 char dummy;
252
253 if ((sscanf(name, "%u:%u%c", &maj, &min, &dummy) == 2) ||
254 (sscanf(name, "%u:%u:%u:%c", &maj, &min, &offset, &dummy) == 3)) {
255 res = MKDEV(maj, min);
256 if (maj != MAJOR(res) || min != MINOR(res))
257 goto fail;
258 } else {
259 res = new_decode_dev(simple_strtoul(name, &p, 16));
260 if (*p)
261 goto fail;
262 }
263 goto done;
264 }
265
266 name += 5;
267 res = Root_NFS;
268 if (strcmp(name, "nfs") == 0)
269 goto done;
270 res = Root_RAM0;
271 if (strcmp(name, "ram") == 0)
272 goto done;
273
274 if (strlen(name) > 31)
275 goto fail;
276 strcpy(s, name);
277 for (p = s; *p; p++)
278 if (*p == '/')
279 *p = '!';
280 res = blk_lookup_devt(s, 0);
281 if (res)
282 goto done;
283
284 /*
285 * try non-existent, but valid partition, which may only exist
286 * after revalidating the disk, like partitioned md devices
287 */
288 while (p > s && isdigit(p[-1]))
289 p--;
290 if (p == s || !*p || *p == '0')
291 goto fail;
292
293 /* try disk name without <part number> */
294 part = simple_strtoul(p, NULL, 10);
295 *p = '\0';
296 res = blk_lookup_devt(s, part);
297 if (res)
298 goto done;
299
300 /* try disk name without p<part number> */
301 if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p')
302 goto fail;
303 p[-1] = '\0';
304 res = blk_lookup_devt(s, part);
305 if (res)
306 goto done;
307
308fail:
309 return 0;
310done:
311 return res;
312}
313EXPORT_SYMBOL_GPL(name_to_dev_t);
314
315static int __init root_dev_setup(char *line)
316{
317 strlcpy(saved_root_name, line, sizeof(saved_root_name));
318 return 1;
319}
320
321__setup("root=", root_dev_setup);
322
323static int __init rootwait_setup(char *str)
324{
325 if (*str)
326 return 0;
327 root_wait = 1;
328 return 1;
329}
330
331__setup("rootwait", rootwait_setup);
332
333static char * __initdata root_mount_data;
334static int __init root_data_setup(char *str)
335{
336 root_mount_data = str;
337 return 1;
338}
339
340static char * __initdata root_fs_names;
341static int __init fs_names_setup(char *str)
342{
343 root_fs_names = str;
344 return 1;
345}
346
347static unsigned int __initdata root_delay;
348static int __init root_delay_setup(char *str)
349{
350 root_delay = simple_strtoul(str, NULL, 0);
351 return 1;
352}
353
354__setup("rootflags=", root_data_setup);
355__setup("rootfstype=", fs_names_setup);
356__setup("rootdelay=", root_delay_setup);
357
358static void __init get_fs_names(char *page)
359{
360 char *s = page;
361
362 if (root_fs_names) {
363 strcpy(page, root_fs_names);
364 while (*s++) {
365 if (s[-1] == ',')
366 s[-1] = '\0';
367 }
368 } else {
369 int len = get_filesystem_list(page);
370 char *p, *next;
371
372 page[len] = '\0';
373 for (p = page-1; p; p = next) {
374 next = strchr(++p, '\n');
375 if (*p++ != '\t')
376 continue;
377 while ((*s++ = *p++) != '\n')
378 ;
379 s[-1] = '\0';
380 }
381 }
382 *s = '\0';
383}
384
385static int __init do_mount_root(char *name, char *fs, int flags, void *data)
386{
387 struct super_block *s;
388 int err = ksys_mount(name, "/root", fs, flags, data);
389 if (err)
390 return err;
391
392 ksys_chdir("/root");
393 s = current->fs->pwd.dentry->d_sb;
394 ROOT_DEV = s->s_dev;
395 printk(KERN_INFO
396 "VFS: Mounted root (%s filesystem)%s on device %u:%u.\n",
397 s->s_type->name,
398 sb_rdonly(s) ? " readonly" : "",
399 MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
400 return 0;
401}
402
403void __init mount_block_root(char *name, int flags)
404{
405 struct page *page = alloc_page(GFP_KERNEL);
406 char *fs_names = page_address(page);
407 char *p;
408#ifdef CONFIG_BLOCK
409 char b[BDEVNAME_SIZE];
410#else
411 const char *b = name;
412#endif
413
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#ifdef CONFIG_BLOCK
431 __bdevname(ROOT_DEV, b);
432#endif
433 printk("VFS: Cannot open root device \"%s\" or %s: error %d\n",
434 root_device_name, b, err);
435 printk("Please append a correct \"root=\" boot option; here are the available partitions:\n");
436
437 printk_all_partitions();
438#ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT
439 printk("DEBUG_BLOCK_EXT_DEVT is enabled, you need to specify "
440 "explicit textual name for \"root=\" boot option.\n");
441#endif
442 panic("VFS: Unable to mount root fs on %s", b);
443 }
444 if (!(flags & SB_RDONLY)) {
445 flags |= SB_RDONLY;
446 goto retry;
447 }
448
449 printk("List of all partitions:\n");
450 printk_all_partitions();
451 printk("No filesystem could mount root, tried: ");
452 for (p = fs_names; *p; p += strlen(p)+1)
453 printk(" %s", p);
454 printk("\n");
455#ifdef CONFIG_BLOCK
456 __bdevname(ROOT_DEV, b);
457#endif
458 panic("VFS: Unable to mount root fs on %s", b);
459out:
460 put_page(page);
461}
462
463#ifdef CONFIG_ROOT_NFS
464
465#define NFSROOT_TIMEOUT_MIN 5
466#define NFSROOT_TIMEOUT_MAX 30
467#define NFSROOT_RETRY_MAX 5
468
469static int __init mount_nfs_root(void)
470{
471 char *root_dev, *root_data;
472 unsigned int timeout;
473 int try, err;
474
475 err = nfs_root_data(&root_dev, &root_data);
476 if (err != 0)
477 return 0;
478
479 /*
480 * The server or network may not be ready, so try several
481 * times. Stop after a few tries in case the client wants
482 * to fall back to other boot methods.
483 */
484 timeout = NFSROOT_TIMEOUT_MIN;
485 for (try = 1; ; try++) {
486 err = do_mount_root(root_dev, "nfs",
487 root_mountflags, root_data);
488 if (err == 0)
489 return 1;
490 if (try > NFSROOT_RETRY_MAX)
491 break;
492
493 /* Wait, in case the server refused us immediately */
494 ssleep(timeout);
495 timeout <<= 1;
496 if (timeout > NFSROOT_TIMEOUT_MAX)
497 timeout = NFSROOT_TIMEOUT_MAX;
498 }
499 return 0;
500}
501#endif
502
503#if defined(CONFIG_BLK_DEV_RAM) || defined(CONFIG_BLK_DEV_FD)
504void __init change_floppy(char *fmt, ...)
505{
506 struct termios termios;
507 char buf[80];
508 char c;
509 int fd;
510 va_list args;
511 va_start(args, fmt);
512 vsprintf(buf, fmt, args);
513 va_end(args);
514 fd = ksys_open("/dev/root", O_RDWR | O_NDELAY, 0);
515 if (fd >= 0) {
516 ksys_ioctl(fd, FDEJECT, 0);
517 ksys_close(fd);
518 }
519 printk(KERN_NOTICE "VFS: Insert %s and press ENTER\n", buf);
520 fd = ksys_open("/dev/console", O_RDWR, 0);
521 if (fd >= 0) {
522 ksys_ioctl(fd, TCGETS, (long)&termios);
523 termios.c_lflag &= ~ICANON;
524 ksys_ioctl(fd, TCSETSF, (long)&termios);
525 ksys_read(fd, &c, 1);
526 termios.c_lflag |= ICANON;
527 ksys_ioctl(fd, TCSETSF, (long)&termios);
528 ksys_close(fd);
529 }
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 return;
539
540 printk(KERN_ERR "VFS: Unable to mount root fs via NFS, trying floppy.\n");
541 ROOT_DEV = Root_FD0;
542 }
543#endif
544#ifdef CONFIG_BLK_DEV_FD
545 if (MAJOR(ROOT_DEV) == FLOPPY_MAJOR) {
546 /* rd_doload is 2 for a dual initrd/ramload setup */
547 if (rd_doload==2) {
548 if (rd_load_disk(1)) {
549 ROOT_DEV = Root_RAM1;
550 root_device_name = NULL;
551 }
552 } else
553 change_floppy("root floppy");
554 }
555#endif
556#ifdef CONFIG_BLOCK
557 {
558 int err = create_dev("/dev/root", ROOT_DEV);
559
560 if (err < 0)
561 pr_emerg("Failed to create /dev/root: %d\n", err);
562 mount_block_root("/dev/root", root_mountflags);
563 }
564#endif
565}
566
567/*
568 * Prepare the namespace - decide what/where to mount, load ramdisks, etc.
569 */
570void __init prepare_namespace(void)
571{
572 int is_floppy;
573
574 if (root_delay) {
575 printk(KERN_INFO "Waiting %d sec before mounting root device...\n",
576 root_delay);
577 ssleep(root_delay);
578 }
579
580 /*
581 * wait for the known devices to complete their probing
582 *
583 * Note: this is a potential source of long boot delays.
584 * For example, it is not atypical to wait 5 seconds here
585 * for the touchpad of a laptop to initialize.
586 */
587 wait_for_device_probe();
588
589 md_run_setup();
590
591 if (saved_root_name[0]) {
592 root_device_name = saved_root_name;
593 if (!strncmp(root_device_name, "mtd", 3) ||
594 !strncmp(root_device_name, "ubi", 3)) {
595 mount_block_root(root_device_name, root_mountflags);
596 goto out;
597 }
598 ROOT_DEV = name_to_dev_t(root_device_name);
599 if (strncmp(root_device_name, "/dev/", 5) == 0)
600 root_device_name += 5;
601 }
602
603 if (initrd_load())
604 goto out;
605
606 /* wait for any asynchronous scanning to complete */
607 if ((ROOT_DEV == 0) && root_wait) {
608 printk(KERN_INFO "Waiting for root device %s...\n",
609 saved_root_name);
610 while (driver_probe_done() != 0 ||
611 (ROOT_DEV = name_to_dev_t(saved_root_name)) == 0)
612 msleep(5);
613 async_synchronize_full();
614 }
615
616 is_floppy = MAJOR(ROOT_DEV) == FLOPPY_MAJOR;
617
618 if (is_floppy && rd_doload && rd_load_disk(0))
619 ROOT_DEV = Root_RAM0;
620
621 mount_root();
622out:
623 devtmpfs_mount("dev");
624 ksys_mount(".", "/", NULL, MS_MOVE, NULL);
625 ksys_chroot(".");
626}
627
628static bool is_tmpfs;
629static struct dentry *rootfs_mount(struct file_system_type *fs_type,
630 int flags, const char *dev_name, void *data)
631{
632 static unsigned long once;
633 void *fill = ramfs_fill_super;
634
635 if (test_and_set_bit(0, &once))
636 return ERR_PTR(-ENODEV);
637
638 if (IS_ENABLED(CONFIG_TMPFS) && is_tmpfs)
639 fill = shmem_fill_super;
640
641 return mount_nodev(fs_type, flags, data, fill);
642}
643
644static struct file_system_type rootfs_fs_type = {
645 .name = "rootfs",
646 .mount = rootfs_mount,
647 .kill_sb = kill_litter_super,
648};
649
650int __init init_rootfs(void)
651{
652 int err = register_filesystem(&rootfs_fs_type);
653
654 if (err)
655 return err;
656
657 if (IS_ENABLED(CONFIG_TMPFS) && !saved_root_name[0] &&
658 (!root_fs_names || strstr(root_fs_names, "tmpfs"))) {
659 err = shmem_init();
660 is_tmpfs = true;
661 } else {
662 err = init_ramfs_fs();
663 }
664
665 if (err)
666 unregister_filesystem(&rootfs_fs_type);
667
668 return err;
669}
670