xref: /linux/init/do_mounts.c (revision 20d0021394c1b070bf04b22c5bc8fdb437edd4c5)
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/mount.h>
11 
12 #include <linux/nfs_fs.h>
13 #include <linux/nfs_fs_sb.h>
14 #include <linux/nfs_mount.h>
15 
16 #include "do_mounts.h"
17 
18 extern int get_filesystem_list(char * buf);
19 
20 int __initdata rd_doload;	/* 1 = load RAM disk, 0 = don't load */
21 
22 int root_mountflags = MS_RDONLY | MS_VERBOSE;
23 char * __initdata root_device_name;
24 static char __initdata saved_root_name[64];
25 
26 /* this is initialized in init/main.c */
27 dev_t ROOT_DEV;
28 
29 EXPORT_SYMBOL(ROOT_DEV);
30 
31 static int __init load_ramdisk(char *str)
32 {
33 	rd_doload = simple_strtol(str,NULL,0) & 3;
34 	return 1;
35 }
36 __setup("load_ramdisk=", load_ramdisk);
37 
38 static int __init readonly(char *str)
39 {
40 	if (*str)
41 		return 0;
42 	root_mountflags |= MS_RDONLY;
43 	return 1;
44 }
45 
46 static int __init readwrite(char *str)
47 {
48 	if (*str)
49 		return 0;
50 	root_mountflags &= ~MS_RDONLY;
51 	return 1;
52 }
53 
54 __setup("ro", readonly);
55 __setup("rw", readwrite);
56 
57 static dev_t try_name(char *name, int part)
58 {
59 	char path[64];
60 	char buf[32];
61 	int range;
62 	dev_t res;
63 	char *s;
64 	int len;
65 	int fd;
66 	unsigned int maj, min;
67 
68 	/* read device number from .../dev */
69 
70 	sprintf(path, "/sys/block/%s/dev", name);
71 	fd = sys_open(path, 0, 0);
72 	if (fd < 0)
73 		goto fail;
74 	len = sys_read(fd, buf, 32);
75 	sys_close(fd);
76 	if (len <= 0 || len == 32 || buf[len - 1] != '\n')
77 		goto fail;
78 	buf[len - 1] = '\0';
79 	if (sscanf(buf, "%u:%u", &maj, &min) == 2) {
80 		/*
81 		 * Try the %u:%u format -- see print_dev_t()
82 		 */
83 		res = MKDEV(maj, min);
84 		if (maj != MAJOR(res) || min != MINOR(res))
85 			goto fail;
86 	} else {
87 		/*
88 		 * Nope.  Try old-style "0321"
89 		 */
90 		res = new_decode_dev(simple_strtoul(buf, &s, 16));
91 		if (*s)
92 			goto fail;
93 	}
94 
95 	/* if it's there and we are not looking for a partition - that's it */
96 	if (!part)
97 		return res;
98 
99 	/* otherwise read range from .../range */
100 	sprintf(path, "/sys/block/%s/range", name);
101 	fd = sys_open(path, 0, 0);
102 	if (fd < 0)
103 		goto fail;
104 	len = sys_read(fd, buf, 32);
105 	sys_close(fd);
106 	if (len <= 0 || len == 32 || buf[len - 1] != '\n')
107 		goto fail;
108 	buf[len - 1] = '\0';
109 	range = simple_strtoul(buf, &s, 10);
110 	if (*s)
111 		goto fail;
112 
113 	/* if partition is within range - we got it */
114 	if (part < range)
115 		return res + part;
116 fail:
117 	return 0;
118 }
119 
120 /*
121  *	Convert a name into device number.  We accept the following variants:
122  *
123  *	1) device number in hexadecimal	represents itself
124  *	2) /dev/nfs represents Root_NFS (0xff)
125  *	3) /dev/<disk_name> represents the device number of disk
126  *	4) /dev/<disk_name><decimal> represents the device number
127  *         of partition - device number of disk plus the partition number
128  *	5) /dev/<disk_name>p<decimal> - same as the above, that form is
129  *	   used when disk name of partitioned disk ends on a digit.
130  *
131  *	If name doesn't have fall into the categories above, we return 0.
132  *	Driverfs is used to check if something is a disk name - it has
133  *	all known disks under bus/block/devices.  If the disk name
134  *	contains slashes, name of driverfs node has them replaced with
135  *	bangs.  try_name() does the actual checks, assuming that driverfs
136  *	is mounted on rootfs /sys.
137  */
138 
139 dev_t name_to_dev_t(char *name)
140 {
141 	char s[32];
142 	char *p;
143 	dev_t res = 0;
144 	int part;
145 
146 #ifdef CONFIG_SYSFS
147 	int mkdir_err = sys_mkdir("/sys", 0700);
148 	if (sys_mount("sysfs", "/sys", "sysfs", 0, NULL) < 0)
149 		goto out;
150 #endif
151 
152 	if (strncmp(name, "/dev/", 5) != 0) {
153 		unsigned maj, min;
154 
155 		if (sscanf(name, "%u:%u", &maj, &min) == 2) {
156 			res = MKDEV(maj, min);
157 			if (maj != MAJOR(res) || min != MINOR(res))
158 				goto fail;
159 		} else {
160 			res = new_decode_dev(simple_strtoul(name, &p, 16));
161 			if (*p)
162 				goto fail;
163 		}
164 		goto done;
165 	}
166 	name += 5;
167 	res = Root_NFS;
168 	if (strcmp(name, "nfs") == 0)
169 		goto done;
170 	res = Root_RAM0;
171 	if (strcmp(name, "ram") == 0)
172 		goto done;
173 
174 	if (strlen(name) > 31)
175 		goto fail;
176 	strcpy(s, name);
177 	for (p = s; *p; p++)
178 		if (*p == '/')
179 			*p = '!';
180 	res = try_name(s, 0);
181 	if (res)
182 		goto done;
183 
184 	while (p > s && isdigit(p[-1]))
185 		p--;
186 	if (p == s || !*p || *p == '0')
187 		goto fail;
188 	part = simple_strtoul(p, NULL, 10);
189 	*p = '\0';
190 	res = try_name(s, part);
191 	if (res)
192 		goto done;
193 
194 	if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p')
195 		goto fail;
196 	p[-1] = '\0';
197 	res = try_name(s, part);
198 done:
199 #ifdef CONFIG_SYSFS
200 	sys_umount("/sys", 0);
201 out:
202 	if (!mkdir_err)
203 		sys_rmdir("/sys");
204 #endif
205 	return res;
206 fail:
207 	res = 0;
208 	goto done;
209 }
210 
211 static int __init root_dev_setup(char *line)
212 {
213 	strlcpy(saved_root_name, line, sizeof(saved_root_name));
214 	return 1;
215 }
216 
217 __setup("root=", root_dev_setup);
218 
219 static char * __initdata root_mount_data;
220 static int __init root_data_setup(char *str)
221 {
222 	root_mount_data = str;
223 	return 1;
224 }
225 
226 static char * __initdata root_fs_names;
227 static int __init fs_names_setup(char *str)
228 {
229 	root_fs_names = str;
230 	return 1;
231 }
232 
233 static unsigned int __initdata root_delay;
234 static int __init root_delay_setup(char *str)
235 {
236 	root_delay = simple_strtoul(str, NULL, 0);
237 	return 1;
238 }
239 
240 __setup("rootflags=", root_data_setup);
241 __setup("rootfstype=", fs_names_setup);
242 __setup("rootdelay=", root_delay_setup);
243 
244 static void __init get_fs_names(char *page)
245 {
246 	char *s = page;
247 
248 	if (root_fs_names) {
249 		strcpy(page, root_fs_names);
250 		while (*s++) {
251 			if (s[-1] == ',')
252 				s[-1] = '\0';
253 		}
254 	} else {
255 		int len = get_filesystem_list(page);
256 		char *p, *next;
257 
258 		page[len] = '\0';
259 		for (p = page-1; p; p = next) {
260 			next = strchr(++p, '\n');
261 			if (*p++ != '\t')
262 				continue;
263 			while ((*s++ = *p++) != '\n')
264 				;
265 			s[-1] = '\0';
266 		}
267 	}
268 	*s = '\0';
269 }
270 
271 static int __init do_mount_root(char *name, char *fs, int flags, void *data)
272 {
273 	int err = sys_mount(name, "/root", fs, flags, data);
274 	if (err)
275 		return err;
276 
277 	sys_chdir("/root");
278 	ROOT_DEV = current->fs->pwdmnt->mnt_sb->s_dev;
279 	printk("VFS: Mounted root (%s filesystem)%s.\n",
280 	       current->fs->pwdmnt->mnt_sb->s_type->name,
281 	       current->fs->pwdmnt->mnt_sb->s_flags & MS_RDONLY ?
282 	       " readonly" : "");
283 	return 0;
284 }
285 
286 void __init mount_block_root(char *name, int flags)
287 {
288 	char *fs_names = __getname();
289 	char *p;
290 	char b[BDEVNAME_SIZE];
291 
292 	get_fs_names(fs_names);
293 retry:
294 	for (p = fs_names; *p; p += strlen(p)+1) {
295 		int err = do_mount_root(name, p, flags, root_mount_data);
296 		switch (err) {
297 			case 0:
298 				goto out;
299 			case -EACCES:
300 				flags |= MS_RDONLY;
301 				goto retry;
302 			case -EINVAL:
303 				continue;
304 		}
305 	        /*
306 		 * Allow the user to distinguish between failed sys_open
307 		 * and bad superblock on root device.
308 		 */
309 		__bdevname(ROOT_DEV, b);
310 		printk("VFS: Cannot open root device \"%s\" or %s\n",
311 				root_device_name, b);
312 		printk("Please append a correct \"root=\" boot option\n");
313 
314 		panic("VFS: Unable to mount root fs on %s", b);
315 	}
316 	panic("VFS: Unable to mount root fs on %s", __bdevname(ROOT_DEV, b));
317 out:
318 	putname(fs_names);
319 }
320 
321 #ifdef CONFIG_ROOT_NFS
322 static int __init mount_nfs_root(void)
323 {
324 	void *data = nfs_root_data();
325 
326 	create_dev("/dev/root", ROOT_DEV, NULL);
327 	if (data &&
328 	    do_mount_root("/dev/root", "nfs", root_mountflags, data) == 0)
329 		return 1;
330 	return 0;
331 }
332 #endif
333 
334 #if defined(CONFIG_BLK_DEV_RAM) || defined(CONFIG_BLK_DEV_FD)
335 void __init change_floppy(char *fmt, ...)
336 {
337 	struct termios termios;
338 	char buf[80];
339 	char c;
340 	int fd;
341 	va_list args;
342 	va_start(args, fmt);
343 	vsprintf(buf, fmt, args);
344 	va_end(args);
345 	fd = sys_open("/dev/root", O_RDWR | O_NDELAY, 0);
346 	if (fd >= 0) {
347 		sys_ioctl(fd, FDEJECT, 0);
348 		sys_close(fd);
349 	}
350 	printk(KERN_NOTICE "VFS: Insert %s and press ENTER\n", buf);
351 	fd = sys_open("/dev/console", O_RDWR, 0);
352 	if (fd >= 0) {
353 		sys_ioctl(fd, TCGETS, (long)&termios);
354 		termios.c_lflag &= ~ICANON;
355 		sys_ioctl(fd, TCSETSF, (long)&termios);
356 		sys_read(fd, &c, 1);
357 		termios.c_lflag |= ICANON;
358 		sys_ioctl(fd, TCSETSF, (long)&termios);
359 		sys_close(fd);
360 	}
361 }
362 #endif
363 
364 void __init mount_root(void)
365 {
366 #ifdef CONFIG_ROOT_NFS
367 	if (MAJOR(ROOT_DEV) == UNNAMED_MAJOR) {
368 		if (mount_nfs_root())
369 			return;
370 
371 		printk(KERN_ERR "VFS: Unable to mount root fs via NFS, trying floppy.\n");
372 		ROOT_DEV = Root_FD0;
373 	}
374 #endif
375 #ifdef CONFIG_BLK_DEV_FD
376 	if (MAJOR(ROOT_DEV) == FLOPPY_MAJOR) {
377 		/* rd_doload is 2 for a dual initrd/ramload setup */
378 		if (rd_doload==2) {
379 			if (rd_load_disk(1)) {
380 				ROOT_DEV = Root_RAM1;
381 				root_device_name = NULL;
382 			}
383 		} else
384 			change_floppy("root floppy");
385 	}
386 #endif
387 	create_dev("/dev/root", ROOT_DEV, root_device_name);
388 	mount_block_root("/dev/root", root_mountflags);
389 }
390 
391 /*
392  * Prepare the namespace - decide what/where to mount, load ramdisks, etc.
393  */
394 void __init prepare_namespace(void)
395 {
396 	int is_floppy;
397 
398 	mount_devfs();
399 
400 	if (root_delay) {
401 		printk(KERN_INFO "Waiting %dsec before mounting root device...\n",
402 		       root_delay);
403 		ssleep(root_delay);
404 	}
405 
406 	md_run_setup();
407 
408 	if (saved_root_name[0]) {
409 		root_device_name = saved_root_name;
410 		ROOT_DEV = name_to_dev_t(root_device_name);
411 		if (strncmp(root_device_name, "/dev/", 5) == 0)
412 			root_device_name += 5;
413 	}
414 
415 	is_floppy = MAJOR(ROOT_DEV) == FLOPPY_MAJOR;
416 
417 	if (initrd_load())
418 		goto out;
419 
420 	if (is_floppy && rd_doload && rd_load_disk(0))
421 		ROOT_DEV = Root_RAM0;
422 
423 	mount_root();
424 out:
425 	umount_devfs("/dev");
426 	sys_mount(".", "/", NULL, MS_MOVE, NULL);
427 	sys_chroot(".");
428 	security_sb_post_mountroot();
429 	mount_devfs_fs ();
430 }
431 
432