xref: /dragonfly/sys/kern/vfs_conf.c (revision 611395e5) 
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 1.12 2004/09/30 18:59:48 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 
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 namecache *rootncp;
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 static char *cdrom_rootdevnames[] = {
82 	"cd9660:cd0c",
83 	"cd9660:acd0c",
84 	"cd9660:cd1c",
85 	"cd9660:acd1c",
86 	NULL
87 };
88 
89 static void	vfs_mountroot(void *junk);
90 static int	vfs_mountroot_try(const char *mountfrom);
91 static int	vfs_mountroot_ask(void);
92 static void	gets(char *cp);
93 
94 /* legacy find-root code */
95 char		*rootdevnames[2] = {NULL, NULL};
96 static int	setrootbyname(char *name);
97 
98 SYSINIT(mountroot, SI_SUB_MOUNT_ROOT, SI_ORDER_SECOND, vfs_mountroot, NULL);
99 
100 /*
101  * Find and mount the root filesystem
102  */
103 static void
104 vfs_mountroot(void *junk)
105 {
106 	int	i;
107 	dev_t	save_rootdev = rootdev;
108 
109 	/*
110 	 * The root filesystem information is compiled in, and we are
111 	 * booted with instructions to use it.
112 	 */
113 #ifdef ROOTDEVNAME
114 	if ((boothowto & RB_DFLTROOT) &&
115 	    !vfs_mountroot_try(ROOTDEVNAME))
116 		return;
117 #endif
118 	/*
119 	 * We are booted with instructions to prompt for the root filesystem,
120 	 * or to use the compiled-in default when it doesn't exist.
121 	 */
122 	if (boothowto & (RB_DFLTROOT | RB_ASKNAME)) {
123 		if (!vfs_mountroot_ask())
124 			return;
125 	}
126 
127 	/*
128 	 * We've been given the generic "use CDROM as root" flag.  This is
129 	 * necessary because one media may be used in many different
130 	 * devices, so we need to search for them.
131 	 */
132 	if (boothowto & RB_CDROM) {
133 		for (i = 0; cdrom_rootdevnames[i] != NULL; i++) {
134 			if (!vfs_mountroot_try(cdrom_rootdevnames[i]))
135 				return;
136 		}
137 	}
138 
139 	/*
140 	 * Try to use the value read by the loader from /etc/fstab, or
141 	 * supplied via some other means.  This is the preferred
142 	 * mechanism.
143 	 */
144 	if (!vfs_mountroot_try(getenv("vfs.root.mountfrom")))
145 		return;
146 
147 	/*
148 	 * If a vfs set rootdev, try it (XXX VINUM HACK!)
149 	 */
150 	if (save_rootdev != NODEV) {
151 		rootdev = save_rootdev;
152 		if (!vfs_mountroot_try(""))
153 			return;
154 	}
155 
156 	/*
157 	 * Try values that may have been computed by the machine-dependant
158 	 * legacy code.
159 	 */
160 	if (rootdevnames[0] && !vfs_mountroot_try(rootdevnames[0]))
161 		return;
162 	if (rootdevnames[1] && !vfs_mountroot_try(rootdevnames[1]))
163 		return;
164 
165 	/*
166 	 * If we have a compiled-in default, and haven't already tried it, try
167 	 * it now.
168 	 */
169 #ifdef ROOTDEVNAME
170 	if (!(boothowto & RB_DFLTROOT))
171 		if (!vfs_mountroot_try(ROOTDEVNAME))
172 			return;
173 #endif
174 
175 	/*
176 	 * Everything so far has failed, prompt on the console if we haven't
177 	 * already tried that.
178 	 */
179 	if (!(boothowto & (RB_DFLTROOT | RB_ASKNAME)) && !vfs_mountroot_ask())
180 		return;
181 	panic("Root mount failed, startup aborted.");
182 }
183 
184 /*
185  * Mount (mountfrom) as the root filesystem.
186  */
187 static int
188 vfs_mountroot_try(const char *mountfrom)
189 {
190 	struct thread	*td = curthread;
191         struct mount	*mp;
192 	char		*vfsname, *devname;
193 	int		error;
194 	char		patt[32];
195 	lwkt_tokref	ilock;
196 	int		s;
197 
198 	vfsname = NULL;
199 	devname = NULL;
200 	mp      = NULL;
201 	error   = EINVAL;
202 
203 	if (mountfrom == NULL)
204 		return(error);		/* don't complain */
205 
206 	s = splcam();			/* Overkill, but annoying without it */
207 	printf("Mounting root from %s\n", mountfrom);
208 	splx(s);
209 
210 	/* parse vfs name and devname */
211 	vfsname = malloc(MFSNAMELEN, M_MOUNT, M_WAITOK);
212 	devname = malloc(MNAMELEN, M_MOUNT, M_WAITOK);
213 	vfsname[0] = devname[0] = 0;
214 	sprintf(patt, "%%%d[a-z0-9]:%%%ds", MFSNAMELEN, MNAMELEN);
215 	if (sscanf(mountfrom, patt, vfsname, devname) < 1)
216 		goto done;
217 
218 	/* allocate a root mount */
219 	error = vfs_rootmountalloc(vfsname,
220 			devname[0] != 0 ? devname : ROOTNAME, &mp);
221 	if (error != 0) {
222 		printf("Can't allocate root mount for filesystem '%s': %d\n",
223 		       vfsname, error);
224 		goto done;
225 	}
226 	mp->mnt_flag |= MNT_ROOTFS;
227 
228 	/* do our best to set rootdev */
229 	if ((devname[0] != 0) && setrootbyname(devname))
230 		printf("setrootbyname failed\n");
231 
232 	/* If the root device is a type "memory disk", mount RW */
233 	if (rootdev != NODEV && dev_is_good(rootdev) &&
234 	    (dev_dflags(rootdev) & D_MEMDISK)) {
235 		mp->mnt_flag &= ~MNT_RDONLY;
236 	}
237 
238 	error = VFS_MOUNT(mp, NULL, NULL, td);
239 
240 done:
241 	if (vfsname != NULL)
242 		free(vfsname, M_MOUNT);
243 	if (devname != NULL)
244 		free(devname, M_MOUNT);
245 	if (error != 0) {
246 		if (mp != NULL) {
247 			vfs_unbusy(mp, td);
248 			free(mp, M_MOUNT);
249 		}
250 		printf("Root mount failed: %d\n", error);
251 	} else {
252 
253 		/* register with list of mounted filesystems */
254 		lwkt_gettoken(&ilock, &mountlist_token);
255 		TAILQ_INSERT_HEAD(&mountlist, mp, mnt_list);
256 		lwkt_reltoken(&ilock);
257 
258 		/* sanity check system clock against root fs timestamp */
259 		inittodr(mp->mnt_time);
260 		vfs_unbusy(mp, td);
261 	}
262 	return(error);
263 }
264 
265 /*
266  * Spin prompting on the console for a suitable root filesystem
267  */
268 static int
269 vfs_mountroot_ask(void)
270 {
271 	char name[128];
272 	int i;
273 	dev_t dev;
274 
275 	for(;;) {
276 		printf("\nManual root filesystem specification:\n");
277 		printf("  <fstype>:<device>  Mount <device> using filesystem <fstype>\n");
278 		printf("                       eg. ufs:da0s1a\n");
279 		printf("  ?                  List valid disk boot devices\n");
280 		printf("  <empty line>       Abort manual input\n");
281 		printf("\nmountroot> ");
282 		gets(name);
283 		if (name[0] == 0)
284 			return(1);
285 		if (name[0] == '?') {
286 			printf("Possibly valid devices for 'ufs' root:\n");
287 			for (i = 0; i < NUMCDEVSW; i++) {
288 				dev = udev2dev(makeudev(i, 0), 0);
289 				if (dev_is_good(dev))
290 					printf(" \"%s\"", dev_dname(dev));
291 			}
292 			printf("\n");
293 			continue;
294 		}
295 		if (!vfs_mountroot_try(name))
296 			return(0);
297 	}
298 }
299 
300 static void
301 gets(char *cp)
302 {
303 	char *lp;
304 	int c;
305 
306 	lp = cp;
307 	for (;;) {
308 		printf("%c", c = cngetc() & 0177);
309 		switch (c) {
310 		case -1:
311 		case '\n':
312 		case '\r':
313 			*lp++ = '\0';
314 			return;
315 		case '\b':
316 		case '\177':
317 			if (lp > cp) {
318 				printf(" \b");
319 				lp--;
320 			}
321 			continue;
322 		case '#':
323 			lp--;
324 			if (lp < cp)
325 				lp = cp;
326 			continue;
327 		case '@':
328 		case 'u' & 037:
329 			lp = cp;
330 			printf("%c", '\n');
331 			continue;
332 		default:
333 			*lp++ = c;
334 		}
335 	}
336 }
337 
338 /*
339  * Convert a given name to the dev_t of the disk-like device
340  * it refers to.
341  */
342 dev_t
343 getdiskbyname(const char *name)
344 {
345 	char *cp;
346 	int nlen;
347 	int cd, unit, slice, part;
348 	dev_t dev;
349 	dev_t rdev;
350 
351 	/*
352 	 * Get the base name of the device
353 	 */
354 	if (strncmp(name, __SYS_PATH_DEV, sizeof(__SYS_PATH_DEV) - 1) == 0)
355 		name += sizeof(__SYS_PATH_DEV) - 1;
356 	cp = __DECONST(char *, name);
357 	while (*cp == '/')
358 		++cp;
359 	while (*cp >= 'a' && *cp <= 'z')
360 		++cp;
361 	if (cp == name) {
362 		printf("missing device name\n");
363 		return (NODEV);
364 	}
365 	nlen = cp - name;
366 
367 	/*
368 	 * Get the unit.
369 	 */
370 	unit = strtol(cp, &cp, 10);
371 	if (name + nlen == (const char *)cp || unit < 0 || unit > DKMAXUNIT) {
372 		printf("bad unit: %d\n", unit);
373 		return (NODEV);
374 	}
375 
376 	/*
377 	 * Get the slice.  Note that if no partition or partition 'a' is
378 	 * specified, and no slice is specified, we will try both 'ad0a'
379 	 * (which is what you get when slice is 0), and also 'ad0' (the
380 	 * whole-disk partition, slice == 1).
381 	 */
382 	if (*cp == 's') {
383 		slice = cp[1] - '0';
384 		if (slice < 1 || slice > 9) {
385 			printf("bad slice number\n");
386 			return(NODEV);
387 		}
388 		++slice;	/* slice #1 starts at 2 */
389 		cp += 2;
390 	} else {
391 		slice = 0;
392 	}
393 
394 	/*
395 	 * Get the partition.
396 	 */
397 	if (*cp >= 'a' && *cp <= 'p') {
398 		part = *cp - 'a';
399 		++cp;
400 	} else {
401 		part = 0;
402 	}
403 
404 	if (*cp != '\0') {
405 		printf("junk after name\n");
406 		return (NODEV);
407 	}
408 
409 	/*
410 	 * Locate the device
411 	 */
412 	for (cd = 0; cd < NUMCDEVSW; cd++) {
413 		const char *dname;
414 
415 		dev = udev2dev(makeudev(cd, dkmakeminor(unit, slice, part)), 0);
416 		if (dev_is_good(dev) && (dname = dev_dname(dev)) != NULL) {
417 			if (strlen(dname) == nlen &&
418 			    strncmp(dname, name, nlen) == 0) {
419 				break;
420 			}
421 		}
422 	}
423 	if (cd == NUMCDEVSW) {
424 		printf("no such device '%*.*s'\n", nlen, nlen, name);
425 		return (NODEV);
426 	}
427 
428 	/*
429 	 * FOUND DEVICE
430 	 */
431 	rdev = make_sub_dev(dev, dkmakeminor(unit, slice, part));
432 	return(rdev);
433 }
434 
435 /*
436  * Set rootdev to match (name), given that we expect it to
437  * refer to a disk-like device.
438  */
439 static int
440 setrootbyname(char *name)
441 {
442 	dev_t diskdev;
443 
444 	diskdev = getdiskbyname(name);
445 	if (diskdev != NODEV) {
446 		rootdev = diskdev;
447 		return (0);
448 	}
449 
450 	return (1);
451 }
452 
453 #ifdef DDB
454 DB_SHOW_COMMAND(disk, db_getdiskbyname)
455 {
456 	dev_t dev;
457 
458 	if (modif[0] == '\0') {
459 		db_error("usage: show disk/devicename");
460 		return;
461 	}
462 	dev = getdiskbyname(modif);
463 	if (dev != NODEV)
464 		db_printf("dev_t = %p\n", dev);
465 	else
466 		db_printf("No disk device matched.\n");
467 }
468 #endif
469