xref: /dragonfly/sys/kern/vfs_conf.c (revision 19fe1c42) 
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 1.34 2008/05/24 19:08:28 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/conf.h>
58 #include <sys/cons.h>
59 #include <sys/device.h>
60 #include <sys/namecache.h>
61 #include <sys/paths.h>
62 #include <sys/thread2.h>
63 
64 #include "opt_ddb.h"
65 #ifdef DDB
66 #include <ddb/ddb.h>
67 #endif
68 
69 MALLOC_DEFINE(M_MOUNT, "mount", "vfs mount structure");
70 
71 #define ROOTNAME	"root_device"
72 
73 struct vnode	*rootvnode;
74 struct nchandle rootnch;
75 
76 /*
77  * The root specifiers we will try if RB_CDROM is specified.  Note that
78  * the ATA driver will accept acd*a and acd*c, but the SCSI driver
79  * will only accept cd*c, so use 'c'.
80  *
81  * XXX TGEN NATA and, presumably, 'old'ATA will also accept the device name
82  * without any fake partition, since the major & minor are identical for all
83  * three (acd*, acd*a and acd*c). However, due to an as-of-yet undiscovered
84  * bug, acd0c ends up with minor 2 when using NATA and booting cold. Since
85  * NATA's acd_open() is unable to fulfill mounts on such 'ghost' cdevs, acd0
86  * and acd1 have been added to the list of CD-ROM root device names.
87  */
88 static char *cdrom_rootdevnames[] = {
89 	"cd9660:cd0c",
90 	"cd9660:acd0c",
91 	"cd9660:cd1c",
92 	"cd9660:acd1c",
93 	"cd9660:acd0",
94 	"cd9660:acd1",
95 	NULL
96 };
97 
98 static void	vfs_mountroot(void *junk);
99 static int	vfs_mountroot_try(const char *mountfrom);
100 static int	vfs_mountroot_ask(void);
101 static int	getline(char *cp, int limit);
102 
103 /* legacy find-root code */
104 char		*rootdevnames[2] = {NULL, NULL};
105 static int	setrootbyname(char *name);
106 
107 SYSINIT(mountroot, SI_SUB_MOUNT_ROOT, SI_ORDER_SECOND, vfs_mountroot, NULL);
108 
109 /*
110  * Find and mount the root filesystem
111  */
112 static void
113 vfs_mountroot(void *junk)
114 {
115 	int	i;
116 	cdev_t	save_rootdev = rootdev;
117 
118 	/*
119 	 * The root filesystem information is compiled in, and we are
120 	 * booted with instructions to use it.
121 	 */
122 #ifdef ROOTDEVNAME
123 	if ((boothowto & RB_DFLTROOT) &&
124 	    !vfs_mountroot_try(ROOTDEVNAME))
125 		return;
126 #endif
127 	/*
128 	 * We are booted with instructions to prompt for the root filesystem,
129 	 * or to use the compiled-in default when it doesn't exist.
130 	 */
131 	if (boothowto & (RB_DFLTROOT | RB_ASKNAME)) {
132 		if (!vfs_mountroot_ask())
133 			return;
134 	}
135 
136 	/*
137 	 * We've been given the generic "use CDROM as root" flag.  This is
138 	 * necessary because one media may be used in many different
139 	 * devices, so we need to search for them.
140 	 */
141 	if (boothowto & RB_CDROM) {
142 		for (i = 0; cdrom_rootdevnames[i] != NULL; i++) {
143 			if (!vfs_mountroot_try(cdrom_rootdevnames[i]))
144 				return;
145 		}
146 	}
147 
148 	/*
149 	 * Try to use the value read by the loader from /etc/fstab, or
150 	 * supplied via some other means.  This is the preferred
151 	 * mechanism.
152 	 */
153 	if (!vfs_mountroot_try(kgetenv("vfs.root.mountfrom")))
154 		return;
155 
156 	/*
157 	 * If a vfs set rootdev, try it (XXX VINUM HACK!)
158 	 */
159 	if (save_rootdev != NULL) {
160 		rootdev = save_rootdev;
161 		if (!vfs_mountroot_try(""))
162 			return;
163 	}
164 
165 	/*
166 	 * Try values that may have been computed by the machine-dependant
167 	 * legacy code.
168 	 */
169 	if (rootdevnames[0] && !vfs_mountroot_try(rootdevnames[0]))
170 		return;
171 	if (rootdevnames[1] && !vfs_mountroot_try(rootdevnames[1]))
172 		return;
173 
174 	/*
175 	 * If we have a compiled-in default, and haven't already tried it, try
176 	 * it now.
177 	 */
178 #ifdef ROOTDEVNAME
179 	if (!(boothowto & RB_DFLTROOT))
180 		if (!vfs_mountroot_try(ROOTDEVNAME))
181 			return;
182 #endif
183 
184 	/*
185 	 * Everything so far has failed, prompt on the console if we haven't
186 	 * already tried that.
187 	 */
188 	if (!(boothowto & (RB_DFLTROOT | RB_ASKNAME)) && !vfs_mountroot_ask())
189 		return;
190 	panic("Root mount failed, startup aborted.");
191 }
192 
193 /*
194  * Mount (mountfrom) as the root filesystem.
195  */
196 static int
197 vfs_mountroot_try(const char *mountfrom)
198 {
199         struct mount	*mp;
200 	char		*vfsname, *devname;
201 	int		error;
202 	char		patt[32];
203 
204 	vfsname = NULL;
205 	devname = NULL;
206 	mp      = NULL;
207 	error   = EINVAL;
208 
209 	if (mountfrom == NULL)
210 		return(error);		/* don't complain */
211 
212 	crit_enter();
213 	kprintf("Mounting root from %s\n", mountfrom);
214 	crit_exit();
215 
216 	/* parse vfs name and devname */
217 	vfsname = kmalloc(MFSNAMELEN, M_MOUNT, M_WAITOK);
218 	devname = kmalloc(MNAMELEN, M_MOUNT, M_WAITOK);
219 	vfsname[0] = devname[0] = 0;
220 	ksprintf(patt, "%%%d[a-z0-9]:%%%ds", MFSNAMELEN, MNAMELEN);
221 	if (ksscanf(mountfrom, patt, vfsname, devname) < 1)
222 		goto done;
223 
224 	/* allocate a root mount */
225 	error = vfs_rootmountalloc(vfsname,
226 			devname[0] != 0 ? devname : ROOTNAME, &mp);
227 	if (error != 0) {
228 		kprintf("Can't allocate root mount for filesystem '%s': %d\n",
229 		       vfsname, error);
230 		goto done;
231 	}
232 	mp->mnt_flag |= MNT_ROOTFS;
233 
234 	/* do our best to set rootdev */
235 	if ((devname[0] != 0) && setrootbyname(devname))
236 		kprintf("setrootbyname failed\n");
237 
238 	/* If the root device is a type "memory disk", mount RW */
239 	if (rootdev != NULL && dev_is_good(rootdev) &&
240 	    (dev_dflags(rootdev) & D_MEMDISK)) {
241 		mp->mnt_flag &= ~MNT_RDONLY;
242 	}
243 
244 	error = VFS_MOUNT(mp, NULL, NULL, proc0.p_ucred);
245 
246 done:
247 	if (vfsname != NULL)
248 		kfree(vfsname, M_MOUNT);
249 	if (devname != NULL)
250 		kfree(devname, M_MOUNT);
251 	if (error == 0) {
252 		/* register with list of mounted filesystems */
253 		mountlist_insert(mp, MNTINS_FIRST);
254 
255 		/* sanity check system clock against root fs timestamp */
256 		inittodr(mp->mnt_time);
257 		vfs_unbusy(mp);
258 		if (mp->mnt_syncer == NULL) {
259 			error = vfs_allocate_syncvnode(mp);
260 			if (error)
261 				kprintf("Warning: no syncer vp for root!\n");
262 			error = 0;
263 		}
264 	} else {
265 		if (mp != NULL) {
266 			vfs_unbusy(mp);
267 			kfree(mp, M_MOUNT);
268 		}
269 		kprintf("Root mount failed: %d\n", error);
270 	}
271 	return(error);
272 }
273 
274 /*
275  * Spin prompting on the console for a suitable root filesystem
276  */
277 static int vfs_mountroot_ask_callback(struct dev_ops *ops, void *arg);
278 
279 static int
280 vfs_mountroot_ask(void)
281 {
282 	char name[128];
283 	int llimit = 100;
284 
285 	kprintf("\nManual root filesystem specification:\n");
286 	kprintf("  <fstype>:<device>  Specify root (e.g. ufs:da0s1a)\n");
287 	kprintf("  ?                  List valid disk boot devices\n");
288 	kprintf("  panic              Just panic\n");
289 	kprintf("  abort              Abort manual input\n");
290 	while (llimit--) {
291 		kprintf("\nmountroot> ");
292 
293 		if (getline(name, 128) < 0)
294 			break;
295 		if (name[0] == 0) {
296 			;
297 		} else if (name[0] == '?') {
298 			kprintf("Possibly valid devices for 'ufs' root:\n");
299 			dev_ops_scan(vfs_mountroot_ask_callback, NULL);
300 			kprintf("\n");
301 			continue;
302 		} else if (strcmp(name, "panic") == 0) {
303 			panic("panic from console");
304 		} else if (strcmp(name, "abort") == 0) {
305 			break;
306 		} else if (vfs_mountroot_try(name) == 0) {
307 			return(0);
308 		}
309 	}
310 	return(1);
311 }
312 
313 static int
314 vfs_mountroot_ask_callback(struct dev_ops *ops, void *arg __unused)
315 {
316 	cdev_t dev;
317 
318 	dev = get_dev(ops->head.maj, 0);
319 	if (dev_is_good(dev) && (dev_dflags(dev) & D_DISK))
320 		kprintf(" \"%s\"", dev_dname(dev));
321 	return(0);
322 }
323 
324 static int
325 getline(char *cp, int limit)
326 {
327 	char *lp;
328 	int c;
329 
330 	lp = cp;
331 	for (;;) {
332 		c = cngetc();
333 
334 		switch (c) {
335 		case -1:
336 			return(-1);
337 		case '\n':
338 		case '\r':
339 			kprintf("\n");
340 			*lp++ = '\0';
341 			return(0);
342 		case '\b':
343 		case '\177':
344 			if (lp > cp) {
345 				kprintf("\b \b");
346 				lp--;
347 			} else {
348 				kprintf("%c", 7);
349 			}
350 			continue;
351 		case '#':
352 			kprintf("#");
353 			lp--;
354 			if (lp < cp)
355 				lp = cp;
356 			continue;
357 		case '@':
358 		case 'u' & 037:
359 			lp = cp;
360 			kprintf("%c", '\n');
361 			continue;
362 		default:
363 			if (lp - cp >= limit - 1) {
364 				kprintf("%c", 7);
365 			} else {
366 				kprintf("%c", c);
367 				*lp++ = c;
368 			}
369 			continue;
370 		}
371 	}
372 }
373 
374 /*
375  * Convert a given name to the cdev_t of the disk-like device
376  * it refers to.
377  */
378 struct kdbn_info {
379 	const char *name;
380 	int nlen;
381 	int minor;
382 	cdev_t dev;
383 };
384 
385 static int kgetdiskbyname_callback(struct dev_ops *ops, void *arg);
386 
387 cdev_t
388 kgetdiskbyname(const char *name)
389 {
390 	char *cp;
391 	int nlen;
392 	int unit, slice, part;
393 	cdev_t rdev;
394 	struct kdbn_info info;
395 
396 	/*
397 	 * Get the base name of the device
398 	 */
399 	if (strncmp(name, __SYS_PATH_DEV, sizeof(__SYS_PATH_DEV) - 1) == 0)
400 		name += sizeof(__SYS_PATH_DEV) - 1;
401 	cp = __DECONST(char *, name);
402 	while (*cp == '/')
403 		++cp;
404 	while (*cp >= 'a' && *cp <= 'z')
405 		++cp;
406 	if (cp == name) {
407 		kprintf("missing device name\n");
408 		return (NULL);
409 	}
410 	nlen = cp - name;
411 
412 	/*
413 	 * Get the unit.
414 	 */
415 	unit = strtol(cp, &cp, 10);
416 	if (name + nlen == (const char *)cp || unit < 0 || unit >= DKMAXUNITS) {
417 		kprintf("bad unit: %d\n", unit);
418 		return (NULL);
419 	}
420 
421 	/*
422 	 * Get the slice.  Note that if no partition or partition 'a' is
423 	 * specified, and no slice is specified, we will try both 'ad0a'
424 	 * (which is what you get when slice is 0), and also 'ad0' (the
425 	 * whole-disk partition, slice == 1).
426 	 */
427 	if (*cp == 's') {
428 		slice = cp[1] - '0';
429 		if (slice >= 1)
430 			++slice;
431 		cp += 2;
432 	} else {
433 		slice = 0;
434 	}
435 
436 	/*
437 	 * Get the partition.
438 	 */
439 	if (*cp >= 'a' && *cp <= 'p') {
440 		part = *cp - 'a';
441 		++cp;
442 	} else {
443 		part = 0;
444 	}
445 
446 	if (*cp != '\0') {
447 		kprintf("junk after name: %s\n", cp);
448 		return (NULL);
449 	}
450 
451 	/*
452 	 * Locate the device
453 	 */
454 	bzero(&info, sizeof(info));
455 	info.nlen = nlen;
456 	info.name = name;
457 	info.minor = dkmakeminor(unit, slice, part);
458 	dev_ops_scan(kgetdiskbyname_callback, &info);
459 	if (info.dev == NULL) {
460 		kprintf("no disk named '%s'\n", name);
461 		return (NULL);
462 	}
463 
464 	/*
465 	 * FOUND DEVICE
466 	 */
467 	rdev = make_sub_dev(info.dev, info.minor);
468 	return(rdev);
469 }
470 
471 static 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