xref: /dragonfly/sys/kern/vfs_conf.c (revision 2cd2d2b5) 
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 1.11 2004/07/20 03:08:23 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/paths.h>
62 
63 #include "opt_ddb.h"
64 #ifdef DDB
65 #include <ddb/ddb.h>
66 #endif
67 
68 MALLOC_DEFINE(M_MOUNT, "mount", "vfs mount structure");
69 
70 #define ROOTNAME	"root_device"
71 
72 struct vnode	*rootvnode;
73 
74 /*
75  * The root specifiers we will try if RB_CDROM is specified.  Note that
76  * the ATA driver will accept acd*a and acd*c, but the SCSI driver
77  * will only accept cd*c, so use 'c'.
78  */
79 static char *cdrom_rootdevnames[] = {
80 	"cd9660:cd0c",
81 	"cd9660:acd0c",
82 	"cd9660:cd1c",
83 	"cd9660:acd1c",
84 	NULL
85 };
86 
87 static void	vfs_mountroot(void *junk);
88 static int	vfs_mountroot_try(const char *mountfrom);
89 static int	vfs_mountroot_ask(void);
90 static void	gets(char *cp);
91 
92 /* legacy find-root code */
93 char		*rootdevnames[2] = {NULL, NULL};
94 static int	setrootbyname(char *name);
95 
96 SYSINIT(mountroot, SI_SUB_MOUNT_ROOT, SI_ORDER_SECOND, vfs_mountroot, NULL);
97 
98 /*
99  * Find and mount the root filesystem
100  */
101 static void
102 vfs_mountroot(void *junk)
103 {
104 	int	i;
105 	dev_t	save_rootdev = rootdev;
106 
107 	/*
108 	 * The root filesystem information is compiled in, and we are
109 	 * booted with instructions to use it.
110 	 */
111 #ifdef ROOTDEVNAME
112 	if ((boothowto & RB_DFLTROOT) &&
113 	    !vfs_mountroot_try(ROOTDEVNAME))
114 		return;
115 #endif
116 	/*
117 	 * We are booted with instructions to prompt for the root filesystem,
118 	 * or to use the compiled-in default when it doesn't exist.
119 	 */
120 	if (boothowto & (RB_DFLTROOT | RB_ASKNAME)) {
121 		if (!vfs_mountroot_ask())
122 			return;
123 	}
124 
125 	/*
126 	 * We've been given the generic "use CDROM as root" flag.  This is
127 	 * necessary because one media may be used in many different
128 	 * devices, so we need to search for them.
129 	 */
130 	if (boothowto & RB_CDROM) {
131 		for (i = 0; cdrom_rootdevnames[i] != NULL; i++) {
132 			if (!vfs_mountroot_try(cdrom_rootdevnames[i]))
133 				return;
134 		}
135 	}
136 
137 	/*
138 	 * Try to use the value read by the loader from /etc/fstab, or
139 	 * supplied via some other means.  This is the preferred
140 	 * mechanism.
141 	 */
142 	if (!vfs_mountroot_try(getenv("vfs.root.mountfrom")))
143 		return;
144 
145 	/*
146 	 * If a vfs set rootdev, try it (XXX VINUM HACK!)
147 	 */
148 	if (save_rootdev != NODEV) {
149 		rootdev = save_rootdev;
150 		if (!vfs_mountroot_try(""))
151 			return;
152 	}
153 
154 	/*
155 	 * Try values that may have been computed by the machine-dependant
156 	 * legacy code.
157 	 */
158 	if (rootdevnames[0] && !vfs_mountroot_try(rootdevnames[0]))
159 		return;
160 	if (rootdevnames[1] && !vfs_mountroot_try(rootdevnames[1]))
161 		return;
162 
163 	/*
164 	 * If we have a compiled-in default, and haven't already tried it, try
165 	 * it now.
166 	 */
167 #ifdef ROOTDEVNAME
168 	if (!(boothowto & RB_DFLTROOT))
169 		if (!vfs_mountroot_try(ROOTDEVNAME))
170 			return;
171 #endif
172 
173 	/*
174 	 * Everything so far has failed, prompt on the console if we haven't
175 	 * already tried that.
176 	 */
177 	if (!(boothowto & (RB_DFLTROOT | RB_ASKNAME)) && !vfs_mountroot_ask())
178 		return;
179 	panic("Root mount failed, startup aborted.");
180 }
181 
182 /*
183  * Mount (mountfrom) as the root filesystem.
184  */
185 static int
186 vfs_mountroot_try(const char *mountfrom)
187 {
188 	struct thread	*td = curthread;
189         struct mount	*mp;
190 	char		*vfsname, *devname;
191 	int		error;
192 	char		patt[32];
193 	lwkt_tokref	ilock;
194 	int		s;
195 
196 	vfsname = NULL;
197 	devname = NULL;
198 	mp      = NULL;
199 	error   = EINVAL;
200 
201 	if (mountfrom == NULL)
202 		return(error);		/* don't complain */
203 
204 	s = splcam();			/* Overkill, but annoying without it */
205 	printf("Mounting root from %s\n", mountfrom);
206 	splx(s);
207 
208 	/* parse vfs name and devname */
209 	vfsname = malloc(MFSNAMELEN, M_MOUNT, M_WAITOK);
210 	devname = malloc(MNAMELEN, M_MOUNT, M_WAITOK);
211 	vfsname[0] = devname[0] = 0;
212 	sprintf(patt, "%%%d[a-z0-9]:%%%ds", MFSNAMELEN, MNAMELEN);
213 	if (sscanf(mountfrom, patt, vfsname, devname) < 1)
214 		goto done;
215 
216 	/* allocate a root mount */
217 	error = vfs_rootmountalloc(vfsname,
218 			devname[0] != 0 ? devname : ROOTNAME, &mp);
219 	if (error != 0) {
220 		printf("Can't allocate root mount for filesystem '%s': %d\n",
221 		       vfsname, error);
222 		goto done;
223 	}
224 	mp->mnt_flag |= MNT_ROOTFS;
225 
226 	/* do our best to set rootdev */
227 	if ((devname[0] != 0) && setrootbyname(devname))
228 		printf("setrootbyname failed\n");
229 
230 	/* If the root device is a type "memory disk", mount RW */
231 	if (rootdev != NODEV && dev_is_good(rootdev) &&
232 	    (dev_dflags(rootdev) & D_MEMDISK)) {
233 		mp->mnt_flag &= ~MNT_RDONLY;
234 	}
235 
236 	error = VFS_MOUNT(mp, NULL, NULL, NULL, td);
237 
238 done:
239 	if (vfsname != NULL)
240 		free(vfsname, M_MOUNT);
241 	if (devname != NULL)
242 		free(devname, M_MOUNT);
243 	if (error != 0) {
244 		if (mp != NULL) {
245 			vfs_unbusy(mp, td);
246 			free(mp, M_MOUNT);
247 		}
248 		printf("Root mount failed: %d\n", error);
249 	} else {
250 
251 		/* register with list of mounted filesystems */
252 		lwkt_gettoken(&ilock, &mountlist_token);
253 		TAILQ_INSERT_HEAD(&mountlist, mp, mnt_list);
254 		lwkt_reltoken(&ilock);
255 
256 		/* sanity check system clock against root fs timestamp */
257 		inittodr(mp->mnt_time);
258 		vfs_unbusy(mp, td);
259 	}
260 	return(error);
261 }
262 
263 /*
264  * Spin prompting on the console for a suitable root filesystem
265  */
266 static int
267 vfs_mountroot_ask(void)
268 {
269 	char name[128];
270 	int i;
271 	dev_t dev;
272 
273 	for(;;) {
274 		printf("\nManual root filesystem specification:\n");
275 		printf("  <fstype>:<device>  Mount <device> using filesystem <fstype>\n");
276 		printf("                       eg. ufs:da0s1a\n");
277 		printf("  ?                  List valid disk boot devices\n");
278 		printf("  <empty line>       Abort manual input\n");
279 		printf("\nmountroot> ");
280 		gets(name);
281 		if (name[0] == 0)
282 			return(1);
283 		if (name[0] == '?') {
284 			printf("Possibly valid devices for 'ufs' root:\n");
285 			for (i = 0; i < NUMCDEVSW; i++) {
286 				dev = udev2dev(makeudev(i, 0), 0);
287 				if (dev_is_good(dev))
288 					printf(" \"%s\"", dev_dname(dev));
289 			}
290 			printf("\n");
291 			continue;
292 		}
293 		if (!vfs_mountroot_try(name))
294 			return(0);
295 	}
296 }
297 
298 static void
299 gets(char *cp)
300 {
301 	char *lp;
302 	int c;
303 
304 	lp = cp;
305 	for (;;) {
306 		printf("%c", c = cngetc() & 0177);
307 		switch (c) {
308 		case -1:
309 		case '\n':
310 		case '\r':
311 			*lp++ = '\0';
312 			return;
313 		case '\b':
314 		case '\177':
315 			if (lp > cp) {
316 				printf(" \b");
317 				lp--;
318 			}
319 			continue;
320 		case '#':
321 			lp--;
322 			if (lp < cp)
323 				lp = cp;
324 			continue;
325 		case '@':
326 		case 'u' & 037:
327 			lp = cp;
328 			printf("%c", '\n');
329 			continue;
330 		default:
331 			*lp++ = c;
332 		}
333 	}
334 }
335 
336 /*
337  * Convert a given name to the dev_t of the disk-like device
338  * it refers to.
339  */
340 dev_t
341 getdiskbyname(const char *name)
342 {
343 	char *cp;
344 	int nlen;
345 	int cd, unit, slice, part;
346 	dev_t dev;
347 	dev_t rdev;
348 
349 	/*
350 	 * Get the base name of the device
351 	 */
352 	if (strncmp(name, __SYS_PATH_DEV, sizeof(__SYS_PATH_DEV) - 1) == 0)
353 		name += sizeof(__SYS_PATH_DEV) - 1;
354 	cp = __DECONST(char *, name);
355 	while (*cp == '/')
356 		++cp;
357 	while (*cp >= 'a' && *cp <= 'z')
358 		++cp;
359 	if (cp == name) {
360 		printf("missing device name\n");
361 		return (NODEV);
362 	}
363 	nlen = cp - name;
364 
365 	/*
366 	 * Get the unit.
367 	 */
368 	unit = strtol(cp, &cp, 10);
369 	if (name + nlen == (const char *)cp || unit < 0 || unit > DKMAXUNIT) {
370 		printf("bad unit: %d\n", unit);
371 		return (NODEV);
372 	}
373 
374 	/*
375 	 * Get the slice.  Note that if no partition or partition 'a' is
376 	 * specified, and no slice is specified, we will try both 'ad0a'
377 	 * (which is what you get when slice is 0), and also 'ad0' (the
378 	 * whole-disk partition, slice == 1).
379 	 */
380 	if (*cp == 's') {
381 		slice = cp[1] - '0';
382 		if (slice < 1 || slice > 9) {
383 			printf("bad slice number\n");
384 			return(NODEV);
385 		}
386 		++slice;	/* slice #1 starts at 2 */
387 		cp += 2;
388 	} else {
389 		slice = 0;
390 	}
391 
392 	/*
393 	 * Get the partition.
394 	 */
395 	if (*cp >= 'a' && *cp <= 'p') {
396 		part = *cp - 'a';
397 		++cp;
398 	} else {
399 		part = 0;
400 	}
401 
402 	if (*cp != '\0') {
403 		printf("junk after name\n");
404 		return (NODEV);
405 	}
406 
407 	/*
408 	 * Locate the device
409 	 */
410 	for (cd = 0; cd < NUMCDEVSW; cd++) {
411 		const char *dname;
412 
413 		dev = udev2dev(makeudev(cd, dkmakeminor(unit, slice, part)), 0);
414 		if (dev_is_good(dev) && (dname = dev_dname(dev)) != NULL) {
415 			if (strlen(dname) == nlen &&
416 			    strncmp(dname, name, nlen) == 0) {
417 				break;
418 			}
419 		}
420 	}
421 	if (cd == NUMCDEVSW) {
422 		printf("no such device '%*.*s'\n", nlen, nlen, name);
423 		return (NODEV);
424 	}
425 
426 	/*
427 	 * FOUND DEVICE
428 	 */
429 	rdev = make_sub_dev(dev, dkmakeminor(unit, slice, part));
430 	return(rdev);
431 }
432 
433 /*
434  * Set rootdev to match (name), given that we expect it to
435  * refer to a disk-like device.
436  */
437 static int
438 setrootbyname(char *name)
439 {
440 	dev_t diskdev;
441 
442 	diskdev = getdiskbyname(name);
443 	if (diskdev != NODEV) {
444 		rootdev = diskdev;
445 		return (0);
446 	}
447 
448 	return (1);
449 }
450 
451 #ifdef DDB
452 DB_SHOW_COMMAND(disk, db_getdiskbyname)
453 {
454 	dev_t dev;
455 
456 	if (modif[0] == '\0') {
457 		db_error("usage: show disk/devicename");
458 		return;
459 	}
460 	dev = getdiskbyname(modif);
461 	if (dev != NODEV)
462 		db_printf("dev_t = %p\n", dev);
463 	else
464 		db_printf("No disk device matched.\n");
465 }
466 #endif
467