xref: /dragonfly/sys/kern/vfs_conf.c (revision 3f5e28f4) 
1 /*-
2  * Copyright (c) 1999 Michael Smith
3  * All rights reserved.
4  * Copyright (c) 1999 Poul-Henning Kamp
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  *
28  *	$FreeBSD: src/sys/kern/vfs_conf.c,v 1.49.2.5 2003/01/07 11:56:53 joerg Exp $
29  *	$DragonFly: src/sys/kern/vfs_conf.c,v 1.29 2007/05/09 00:53:34 dillon Exp $
30  */
31 
32 /*
33  * Locate and mount the root filesystem.
34  *
35  * The root filesystem is detailed in the kernel environment variable
36  * vfs.root.mountfrom, which is expected to be in the general format
37  *
38  * <vfsname>:[<path>]
39  * vfsname   := the name of a VFS known to the kernel and capable
40  *              of being mounted as root
41  * path      := disk device name or other data used by the filesystem
42  *              to locate its physical store
43  *
44  */
45 
46 #include "opt_rootdevname.h"
47 
48 #include <sys/param.h>
49 #include <sys/kernel.h>
50 #include <sys/systm.h>
51 #include <sys/proc.h>
52 #include <sys/vnode.h>
53 #include <sys/mount.h>
54 #include <sys/malloc.h>
55 #include <sys/reboot.h>
56 #include <sys/diskslice.h>
57 #include <sys/disklabel.h>
58 #include <sys/conf.h>
59 #include <sys/cons.h>
60 #include <sys/device.h>
61 #include <sys/namecache.h>
62 #include <sys/paths.h>
63 #include <sys/thread2.h>
64 
65 #include "opt_ddb.h"
66 #ifdef DDB
67 #include <ddb/ddb.h>
68 #endif
69 
70 MALLOC_DEFINE(M_MOUNT, "mount", "vfs mount structure");
71 
72 #define ROOTNAME	"root_device"
73 
74 struct vnode	*rootvnode;
75 struct nchandle rootnch;
76 
77 /*
78  * The root specifiers we will try if RB_CDROM is specified.  Note that
79  * the ATA driver will accept acd*a and acd*c, but the SCSI driver
80  * will only accept cd*c, so use 'c'.
81  *
82  * XXX TGEN NATA and, presumably, 'old'ATA will also accept the device name
83  * without any fake partition, since the major & minor are identical for all
84  * three (acd*, acd*a and acd*c). However, due to an as-of-yet undiscovered
85  * bug, acd0c ends up with minor 2 when using NATA and booting cold. Since
86  * NATA's acd_open() is unable to fulfill mounts on such 'ghost' cdevs, acd0
87  * and acd1 have been added to the list of CD-ROM root device names.
88  */
89 static char *cdrom_rootdevnames[] = {
90 	"cd9660:cd0c",
91 	"cd9660:acd0c",
92 	"cd9660:cd1c",
93 	"cd9660:acd1c",
94 	"cd9660:acd0",
95 	"cd9660:acd1",
96 	NULL
97 };
98 
99 static void	vfs_mountroot(void *junk);
100 static int	vfs_mountroot_try(const char *mountfrom);
101 static int	vfs_mountroot_ask(void);
102 static int	getline(char *cp, int limit);
103 
104 /* legacy find-root code */
105 char		*rootdevnames[2] = {NULL, NULL};
106 static int	setrootbyname(char *name);
107 
108 SYSINIT(mountroot, SI_SUB_MOUNT_ROOT, SI_ORDER_SECOND, vfs_mountroot, NULL);
109 
110 /*
111  * Find and mount the root filesystem
112  */
113 static void
114 vfs_mountroot(void *junk)
115 {
116 	int	i;
117 	cdev_t	save_rootdev = rootdev;
118 
119 	/*
120 	 * The root filesystem information is compiled in, and we are
121 	 * booted with instructions to use it.
122 	 */
123 #ifdef ROOTDEVNAME
124 	if ((boothowto & RB_DFLTROOT) &&
125 	    !vfs_mountroot_try(ROOTDEVNAME))
126 		return;
127 #endif
128 	/*
129 	 * We are booted with instructions to prompt for the root filesystem,
130 	 * or to use the compiled-in default when it doesn't exist.
131 	 */
132 	if (boothowto & (RB_DFLTROOT | RB_ASKNAME)) {
133 		if (!vfs_mountroot_ask())
134 			return;
135 	}
136 
137 	/*
138 	 * We've been given the generic "use CDROM as root" flag.  This is
139 	 * necessary because one media may be used in many different
140 	 * devices, so we need to search for them.
141 	 */
142 	if (boothowto & RB_CDROM) {
143 		for (i = 0; cdrom_rootdevnames[i] != NULL; i++) {
144 			if (!vfs_mountroot_try(cdrom_rootdevnames[i]))
145 				return;
146 		}
147 	}
148 
149 	/*
150 	 * Try to use the value read by the loader from /etc/fstab, or
151 	 * supplied via some other means.  This is the preferred
152 	 * mechanism.
153 	 */
154 	if (!vfs_mountroot_try(kgetenv("vfs.root.mountfrom")))
155 		return;
156 
157 	/*
158 	 * If a vfs set rootdev, try it (XXX VINUM HACK!)
159 	 */
160 	if (save_rootdev != NULL) {
161 		rootdev = save_rootdev;
162 		if (!vfs_mountroot_try(""))
163 			return;
164 	}
165 
166 	/*
167 	 * Try values that may have been computed by the machine-dependant
168 	 * legacy code.
169 	 */
170 	if (rootdevnames[0] && !vfs_mountroot_try(rootdevnames[0]))
171 		return;
172 	if (rootdevnames[1] && !vfs_mountroot_try(rootdevnames[1]))
173 		return;
174 
175 	/*
176 	 * If we have a compiled-in default, and haven't already tried it, try
177 	 * it now.
178 	 */
179 #ifdef ROOTDEVNAME
180 	if (!(boothowto & RB_DFLTROOT))
181 		if (!vfs_mountroot_try(ROOTDEVNAME))
182 			return;
183 #endif
184 
185 	/*
186 	 * Everything so far has failed, prompt on the console if we haven't
187 	 * already tried that.
188 	 */
189 	if (!(boothowto & (RB_DFLTROOT | RB_ASKNAME)) && !vfs_mountroot_ask())
190 		return;
191 	panic("Root mount failed, startup aborted.");
192 }
193 
194 /*
195  * Mount (mountfrom) as the root filesystem.
196  */
197 static int
198 vfs_mountroot_try(const char *mountfrom)
199 {
200         struct mount	*mp;
201 	char		*vfsname, *devname;
202 	int		error;
203 	char		patt[32];
204 
205 	vfsname = NULL;
206 	devname = NULL;
207 	mp      = NULL;
208 	error   = EINVAL;
209 
210 	if (mountfrom == NULL)
211 		return(error);		/* don't complain */
212 
213 	crit_enter();
214 	kprintf("Mounting root from %s\n", mountfrom);
215 	crit_exit();
216 
217 	/* parse vfs name and devname */
218 	vfsname = kmalloc(MFSNAMELEN, M_MOUNT, M_WAITOK);
219 	devname = kmalloc(MNAMELEN, M_MOUNT, M_WAITOK);
220 	vfsname[0] = devname[0] = 0;
221 	ksprintf(patt, "%%%d[a-z0-9]:%%%ds", MFSNAMELEN, MNAMELEN);
222 	if (ksscanf(mountfrom, patt, vfsname, devname) < 1)
223 		goto done;
224 
225 	/* allocate a root mount */
226 	error = vfs_rootmountalloc(vfsname,
227 			devname[0] != 0 ? devname : ROOTNAME, &mp);
228 	if (error != 0) {
229 		kprintf("Can't allocate root mount for filesystem '%s': %d\n",
230 		       vfsname, error);
231 		goto done;
232 	}
233 	mp->mnt_flag |= MNT_ROOTFS;
234 
235 	/* do our best to set rootdev */
236 	if ((devname[0] != 0) && setrootbyname(devname))
237 		kprintf("setrootbyname failed\n");
238 
239 	/* If the root device is a type "memory disk", mount RW */
240 	if (rootdev != NULL && dev_is_good(rootdev) &&
241 	    (dev_dflags(rootdev) & D_MEMDISK)) {
242 		mp->mnt_flag &= ~MNT_RDONLY;
243 	}
244 
245 	error = VFS_MOUNT(mp, NULL, NULL, proc0.p_ucred);
246 
247 done:
248 	if (vfsname != NULL)
249 		kfree(vfsname, M_MOUNT);
250 	if (devname != NULL)
251 		kfree(devname, M_MOUNT);
252 	if (error != 0) {
253 		if (mp != NULL) {
254 			vfs_unbusy(mp);
255 			kfree(mp, M_MOUNT);
256 		}
257 		kprintf("Root mount failed: %d\n", error);
258 	} else {
259 		/* register with list of mounted filesystems */
260 		mountlist_insert(mp, MNTINS_FIRST);
261 
262 		/* sanity check system clock against root fs timestamp */
263 		inittodr(mp->mnt_time);
264 		vfs_unbusy(mp);
265 	}
266 	return(error);
267 }
268 
269 /*
270  * Spin prompting on the console for a suitable root filesystem
271  */
272 static int vfs_mountroot_ask_callback(struct dev_ops *ops, void *arg);
273 
274 static int
275 vfs_mountroot_ask(void)
276 {
277 	char name[128];
278 	int llimit = 100;
279 
280 	kprintf("\nManual root filesystem specification:\n");
281 	kprintf("  <fstype>:<device>  Specify root (e.g. ufs:da0s1a)\n");
282 	kprintf("  ?                  List valid disk boot devices\n");
283 	kprintf("  panic              Just panic\n");
284 	kprintf("  abort              Abort manual input\n");
285 	while (llimit--) {
286 		kprintf("\nmountroot> ");
287 
288 		if (getline(name, 128) < 0)
289 			break;
290 		if (name[0] == 0) {
291 			;
292 		} else if (name[0] == '?') {
293 			kprintf("Possibly valid devices for 'ufs' root:\n");
294 			dev_ops_scan(vfs_mountroot_ask_callback, NULL);
295 			kprintf("\n");
296 			continue;
297 		} else if (strcmp(name, "panic") == 0) {
298 			panic("panic from console");
299 		} else if (strcmp(name, "abort") == 0) {
300 			break;
301 		} else if (vfs_mountroot_try(name) == 0) {
302 			return(0);
303 		}
304 	}
305 	return(1);
306 }
307 
308 static
309 int
310 vfs_mountroot_ask_callback(struct dev_ops *ops, void *arg __unused)
311 {
312 	cdev_t dev;
313 
314 	dev = get_dev(ops->head.maj, 0);
315 	if (dev_is_good(dev))
316 		kprintf(" \"%s\"", dev_dname(dev));
317 	return(0);
318 }
319 
320 static int
321 getline(char *cp, int limit)
322 {
323 	char *lp;
324 	int c;
325 
326 	lp = cp;
327 	for (;;) {
328 		c = cngetc();
329 
330 		switch (c) {
331 		case -1:
332 			return(-1);
333 		case '\n':
334 		case '\r':
335 			kprintf("\n");
336 			*lp++ = '\0';
337 			return(0);
338 		case '\b':
339 		case '\177':
340 			if (lp > cp) {
341 				kprintf("\b \b");
342 				lp--;
343 			} else {
344 				kprintf("%c", 7);
345 			}
346 			continue;
347 		case '#':
348 			kprintf("#");
349 			lp--;
350 			if (lp < cp)
351 				lp = cp;
352 			continue;
353 		case '@':
354 		case 'u' & 037:
355 			lp = cp;
356 			kprintf("%c", '\n');
357 			continue;
358 		default:
359 			if (lp - cp >= limit - 1) {
360 				kprintf("%c", 7);
361 			} else {
362 				kprintf("%c", c);
363 				*lp++ = c;
364 			}
365 			continue;
366 		}
367 	}
368 }
369 
370 /*
371  * Convert a given name to the cdev_t of the disk-like device
372  * it refers to.
373  */
374 struct kdbn_info {
375 	const char *name;
376 	int nlen;
377 	int minor;
378 	cdev_t dev;
379 };
380 
381 static int kgetdiskbyname_callback(struct dev_ops *ops, void *arg);
382 
383 cdev_t
384 kgetdiskbyname(const char *name)
385 {
386 	char *cp;
387 	int nlen;
388 	int unit, slice, part;
389 	cdev_t rdev;
390 	struct kdbn_info info;
391 
392 	/*
393 	 * Get the base name of the device
394 	 */
395 	if (strncmp(name, __SYS_PATH_DEV, sizeof(__SYS_PATH_DEV) - 1) == 0)
396 		name += sizeof(__SYS_PATH_DEV) - 1;
397 	cp = __DECONST(char *, name);
398 	while (*cp == '/')
399 		++cp;
400 	while (*cp >= 'a' && *cp <= 'z')
401 		++cp;
402 	if (cp == name) {
403 		kprintf("missing device name\n");
404 		return (NULL);
405 	}
406 	nlen = cp - name;
407 
408 	/*
409 	 * Get the unit.
410 	 */
411 	unit = strtol(cp, &cp, 10);
412 	if (name + nlen == (const char *)cp || unit < 0 || unit > DKMAXUNIT) {
413 		kprintf("bad unit: %d\n", unit);
414 		return (NULL);
415 	}
416 
417 	/*
418 	 * Get the slice.  Note that if no partition or partition 'a' is
419 	 * specified, and no slice is specified, we will try both 'ad0a'
420 	 * (which is what you get when slice is 0), and also 'ad0' (the
421 	 * whole-disk partition, slice == 1).
422 	 */
423 	if (*cp == 's') {
424 		slice = cp[1] - '0';
425 		if (slice < 1 || slice > 9) {
426 			kprintf("bad slice number\n");
427 			return(NULL);
428 		}
429 		++slice;	/* slice #1 starts at 2 */
430 		cp += 2;
431 	} else {
432 		slice = 0;
433 	}
434 
435 	/*
436 	 * Get the partition.
437 	 */
438 	if (*cp >= 'a' && *cp <= 'p') {
439 		part = *cp - 'a';
440 		++cp;
441 	} else {
442 		part = 0;
443 	}
444 
445 	if (*cp != '\0') {
446 		kprintf("junk after name\n");
447 		return (NULL);
448 	}
449 
450 	/*
451 	 * Locate the device
452 	 */
453 	bzero(&info, sizeof(info));
454 	info.nlen = nlen;
455 	info.name = name;
456 	info.minor = dkmakeminor(unit, slice, part);
457 	dev_ops_scan(kgetdiskbyname_callback, &info);
458 	if (info.dev == NULL) {
459 		kprintf("no such device '%*.*s'\n", nlen, nlen, name);
460 		return (NULL);
461 	}
462 
463 	/*
464 	 * FOUND DEVICE
465 	 */
466 	rdev = make_sub_dev(info.dev, info.minor);
467 	return(rdev);
468 }
469 
470 static
471 int
472 kgetdiskbyname_callback(struct dev_ops *ops, void *arg)
473 {
474 	struct kdbn_info *info = arg;
475 	cdev_t dev;
476 	const char *dname;
477 
478 	dev = get_dev(ops->head.maj, info->minor);
479 	if (dev_is_good(dev) && (dname = dev_dname(dev)) != NULL) {
480 		if (strlen(dname) == info->nlen &&
481 		    strncmp(dname, info->name, info->nlen) == 0) {
482 			info->dev = dev;
483 			return(-1);
484 		}
485 	}
486 	return(0);
487 }
488 
489 /*
490  * Set rootdev to match (name), given that we expect it to
491  * refer to a disk-like device.
492  */
493 static int
494 setrootbyname(char *name)
495 {
496 	cdev_t diskdev;
497 
498 	diskdev = kgetdiskbyname(name);
499 	if (diskdev != NULL) {
500 		rootdev = diskdev;
501 		return (0);
502 	}
503 
504 	return (1);
505 }
506 
507 #ifdef DDB
508 DB_SHOW_COMMAND(disk, db_getdiskbyname)
509 {
510 	cdev_t dev;
511 
512 	if (modif[0] == '\0') {
513 		db_error("usage: show disk/devicename");
514 		return;
515 	}
516 	dev = kgetdiskbyname(modif);
517 	if (dev != NULL)
518 		db_printf("cdev_t = %p\n", dev);
519 	else
520 		db_printf("No disk device matched.\n");
521 }
522 #endif
523