xref: /dragonfly/sys/kern/vfs_conf.c (revision 6b5c5d0d) 
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 1.33 2007/08/26 16:54:51 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 		if (mp != NULL) {
253 			vfs_unbusy(mp);
254 			kfree(mp, M_MOUNT);
255 		}
256 		kprintf("Root mount failed: %d\n", error);
257 	} else {
258 		/* register with list of mounted filesystems */
259 		mountlist_insert(mp, MNTINS_FIRST);
260 
261 		/* sanity check system clock against root fs timestamp */
262 		inittodr(mp->mnt_time);
263 		vfs_unbusy(mp);
264 	}
265 	return(error);
266 }
267 
268 /*
269  * Spin prompting on the console for a suitable root filesystem
270  */
271 static int vfs_mountroot_ask_callback(struct dev_ops *ops, void *arg);
272 
273 static int
274 vfs_mountroot_ask(void)
275 {
276 	char name[128];
277 	int llimit = 100;
278 
279 	kprintf("\nManual root filesystem specification:\n");
280 	kprintf("  <fstype>:<device>  Specify root (e.g. ufs:da0s1a)\n");
281 	kprintf("  ?                  List valid disk boot devices\n");
282 	kprintf("  panic              Just panic\n");
283 	kprintf("  abort              Abort manual input\n");
284 	while (llimit--) {
285 		kprintf("\nmountroot> ");
286 
287 		if (getline(name, 128) < 0)
288 			break;
289 		if (name[0] == 0) {
290 			;
291 		} else if (name[0] == '?') {
292 			kprintf("Possibly valid devices for 'ufs' root:\n");
293 			dev_ops_scan(vfs_mountroot_ask_callback, NULL);
294 			kprintf("\n");
295 			continue;
296 		} else if (strcmp(name, "panic") == 0) {
297 			panic("panic from console");
298 		} else if (strcmp(name, "abort") == 0) {
299 			break;
300 		} else if (vfs_mountroot_try(name) == 0) {
301 			return(0);
302 		}
303 	}
304 	return(1);
305 }
306 
307 static int
308 vfs_mountroot_ask_callback(struct dev_ops *ops, void *arg __unused)
309 {
310 	cdev_t dev;
311 
312 	dev = get_dev(ops->head.maj, 0);
313 	if (dev_is_good(dev) && (dev_dflags(dev) & D_DISK))
314 		kprintf(" \"%s\"", dev_dname(dev));
315 	return(0);
316 }
317 
318 static int
319 getline(char *cp, int limit)
320 {
321 	char *lp;
322 	int c;
323 
324 	lp = cp;
325 	for (;;) {
326 		c = cngetc();
327 
328 		switch (c) {
329 		case -1:
330 			return(-1);
331 		case '\n':
332 		case '\r':
333 			kprintf("\n");
334 			*lp++ = '\0';
335 			return(0);
336 		case '\b':
337 		case '\177':
338 			if (lp > cp) {
339 				kprintf("\b \b");
340 				lp--;
341 			} else {
342 				kprintf("%c", 7);
343 			}
344 			continue;
345 		case '#':
346 			kprintf("#");
347 			lp--;
348 			if (lp < cp)
349 				lp = cp;
350 			continue;
351 		case '@':
352 		case 'u' & 037:
353 			lp = cp;
354 			kprintf("%c", '\n');
355 			continue;
356 		default:
357 			if (lp - cp >= limit - 1) {
358 				kprintf("%c", 7);
359 			} else {
360 				kprintf("%c", c);
361 				*lp++ = c;
362 			}
363 			continue;
364 		}
365 	}
366 }
367 
368 /*
369  * Convert a given name to the cdev_t of the disk-like device
370  * it refers to.
371  */
372 struct kdbn_info {
373 	const char *name;
374 	int nlen;
375 	int minor;
376 	cdev_t dev;
377 };
378 
379 static int kgetdiskbyname_callback(struct dev_ops *ops, void *arg);
380 
381 cdev_t
382 kgetdiskbyname(const char *name)
383 {
384 	char *cp;
385 	int nlen;
386 	int unit, slice, part;
387 	cdev_t rdev;
388 	struct kdbn_info info;
389 
390 	/*
391 	 * Get the base name of the device
392 	 */
393 	if (strncmp(name, __SYS_PATH_DEV, sizeof(__SYS_PATH_DEV) - 1) == 0)
394 		name += sizeof(__SYS_PATH_DEV) - 1;
395 	cp = __DECONST(char *, name);
396 	while (*cp == '/')
397 		++cp;
398 	while (*cp >= 'a' && *cp <= 'z')
399 		++cp;
400 	if (cp == name) {
401 		kprintf("missing device name\n");
402 		return (NULL);
403 	}
404 	nlen = cp - name;
405 
406 	/*
407 	 * Get the unit.
408 	 */
409 	unit = strtol(cp, &cp, 10);
410 	if (name + nlen == (const char *)cp || unit < 0 || unit >= DKMAXUNITS) {
411 		kprintf("bad unit: %d\n", unit);
412 		return (NULL);
413 	}
414 
415 	/*
416 	 * Get the slice.  Note that if no partition or partition 'a' is
417 	 * specified, and no slice is specified, we will try both 'ad0a'
418 	 * (which is what you get when slice is 0), and also 'ad0' (the
419 	 * whole-disk partition, slice == 1).
420 	 */
421 	if (*cp == 's') {
422 		slice = cp[1] - '0';
423 		if (slice >= 1)
424 			++slice;
425 		cp += 2;
426 	} else {
427 		slice = 0;
428 	}
429 
430 	/*
431 	 * Get the partition.
432 	 */
433 	if (*cp >= 'a' && *cp <= 'p') {
434 		part = *cp - 'a';
435 		++cp;
436 	} else {
437 		part = 0;
438 	}
439 
440 	if (*cp != '\0') {
441 		kprintf("junk after name: %s\n", cp);
442 		return (NULL);
443 	}
444 
445 	/*
446 	 * Locate the device
447 	 */
448 	bzero(&info, sizeof(info));
449 	info.nlen = nlen;
450 	info.name = name;
451 	info.minor = dkmakeminor(unit, slice, part);
452 	dev_ops_scan(kgetdiskbyname_callback, &info);
453 	if (info.dev == NULL) {
454 		kprintf("no disk named '%s'\n", name);
455 		return (NULL);
456 	}
457 
458 	/*
459 	 * FOUND DEVICE
460 	 */
461 	rdev = make_sub_dev(info.dev, info.minor);
462 	return(rdev);
463 }
464 
465 static int
466 kgetdiskbyname_callback(struct dev_ops *ops, void *arg)
467 {
468 	struct kdbn_info *info = arg;
469 	cdev_t dev;
470 	const char *dname;
471 
472 	dev = get_dev(ops->head.maj, info->minor);
473 	if (dev_is_good(dev) && (dname = dev_dname(dev)) != NULL) {
474 		if (strlen(dname) == info->nlen &&
475 		    strncmp(dname, info->name, info->nlen) == 0) {
476 			info->dev = dev;
477 			return(-1);
478 		}
479 	}
480 	return(0);
481 }
482 
483 /*
484  * Set rootdev to match (name), given that we expect it to
485  * refer to a disk-like device.
486  */
487 static int
488 setrootbyname(char *name)
489 {
490 	cdev_t diskdev;
491 
492 	diskdev = kgetdiskbyname(name);
493 	if (diskdev != NULL) {
494 		rootdev = diskdev;
495 		return (0);
496 	}
497 
498 	return (1);
499 }
500 
501 #ifdef DDB
502 DB_SHOW_COMMAND(disk, db_getdiskbyname)
503 {
504 	cdev_t dev;
505 
506 	if (modif[0] == '\0') {
507 		db_error("usage: show disk/devicename");
508 		return;
509 	}
510 	dev = kgetdiskbyname(modif);
511 	if (dev != NULL)
512 		db_printf("cdev_t = %p\n", dev);
513 	else
514 		db_printf("No disk device matched.\n");
515 }
516 #endif
517