xref: /dragonfly/sys/kern/vfs_conf.c (revision 1847e88f) 
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 1.14 2005/06/06 15:02:28 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/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 namecache *rootncp;
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 static char *cdrom_rootdevnames[] = {
83 	"cd9660:cd0c",
84 	"cd9660:acd0c",
85 	"cd9660:cd1c",
86 	"cd9660:acd1c",
87 	NULL
88 };
89 
90 static void	vfs_mountroot(void *junk);
91 static int	vfs_mountroot_try(const char *mountfrom);
92 static int	vfs_mountroot_ask(void);
93 static void	gets(char *cp);
94 
95 /* legacy find-root code */
96 char		*rootdevnames[2] = {NULL, NULL};
97 static int	setrootbyname(char *name);
98 
99 SYSINIT(mountroot, SI_SUB_MOUNT_ROOT, SI_ORDER_SECOND, vfs_mountroot, NULL);
100 
101 /*
102  * Find and mount the root filesystem
103  */
104 static void
105 vfs_mountroot(void *junk)
106 {
107 	int	i;
108 	dev_t	save_rootdev = rootdev;
109 
110 	/*
111 	 * The root filesystem information is compiled in, and we are
112 	 * booted with instructions to use it.
113 	 */
114 #ifdef ROOTDEVNAME
115 	if ((boothowto & RB_DFLTROOT) &&
116 	    !vfs_mountroot_try(ROOTDEVNAME))
117 		return;
118 #endif
119 	/*
120 	 * We are booted with instructions to prompt for the root filesystem,
121 	 * or to use the compiled-in default when it doesn't exist.
122 	 */
123 	if (boothowto & (RB_DFLTROOT | RB_ASKNAME)) {
124 		if (!vfs_mountroot_ask())
125 			return;
126 	}
127 
128 	/*
129 	 * We've been given the generic "use CDROM as root" flag.  This is
130 	 * necessary because one media may be used in many different
131 	 * devices, so we need to search for them.
132 	 */
133 	if (boothowto & RB_CDROM) {
134 		for (i = 0; cdrom_rootdevnames[i] != NULL; i++) {
135 			if (!vfs_mountroot_try(cdrom_rootdevnames[i]))
136 				return;
137 		}
138 	}
139 
140 	/*
141 	 * Try to use the value read by the loader from /etc/fstab, or
142 	 * supplied via some other means.  This is the preferred
143 	 * mechanism.
144 	 */
145 	if (!vfs_mountroot_try(getenv("vfs.root.mountfrom")))
146 		return;
147 
148 	/*
149 	 * If a vfs set rootdev, try it (XXX VINUM HACK!)
150 	 */
151 	if (save_rootdev != NODEV) {
152 		rootdev = save_rootdev;
153 		if (!vfs_mountroot_try(""))
154 			return;
155 	}
156 
157 	/*
158 	 * Try values that may have been computed by the machine-dependant
159 	 * legacy code.
160 	 */
161 	if (rootdevnames[0] && !vfs_mountroot_try(rootdevnames[0]))
162 		return;
163 	if (rootdevnames[1] && !vfs_mountroot_try(rootdevnames[1]))
164 		return;
165 
166 	/*
167 	 * If we have a compiled-in default, and haven't already tried it, try
168 	 * it now.
169 	 */
170 #ifdef ROOTDEVNAME
171 	if (!(boothowto & RB_DFLTROOT))
172 		if (!vfs_mountroot_try(ROOTDEVNAME))
173 			return;
174 #endif
175 
176 	/*
177 	 * Everything so far has failed, prompt on the console if we haven't
178 	 * already tried that.
179 	 */
180 	if (!(boothowto & (RB_DFLTROOT | RB_ASKNAME)) && !vfs_mountroot_ask())
181 		return;
182 	panic("Root mount failed, startup aborted.");
183 }
184 
185 /*
186  * Mount (mountfrom) as the root filesystem.
187  */
188 static int
189 vfs_mountroot_try(const char *mountfrom)
190 {
191 	struct thread	*td = curthread;
192         struct mount	*mp;
193 	char		*vfsname, *devname;
194 	int		error;
195 	char		patt[32];
196 
197 	vfsname = NULL;
198 	devname = NULL;
199 	mp      = NULL;
200 	error   = EINVAL;
201 
202 	if (mountfrom == NULL)
203 		return(error);		/* don't complain */
204 
205 	crit_enter();
206 	printf("Mounting root from %s\n", mountfrom);
207 	crit_exit();
208 
209 	/* parse vfs name and devname */
210 	vfsname = malloc(MFSNAMELEN, M_MOUNT, M_WAITOK);
211 	devname = malloc(MNAMELEN, M_MOUNT, M_WAITOK);
212 	vfsname[0] = devname[0] = 0;
213 	sprintf(patt, "%%%d[a-z0-9]:%%%ds", MFSNAMELEN, MNAMELEN);
214 	if (sscanf(mountfrom, patt, vfsname, devname) < 1)
215 		goto done;
216 
217 	/* allocate a root mount */
218 	error = vfs_rootmountalloc(vfsname,
219 			devname[0] != 0 ? devname : ROOTNAME, &mp);
220 	if (error != 0) {
221 		printf("Can't allocate root mount for filesystem '%s': %d\n",
222 		       vfsname, error);
223 		goto done;
224 	}
225 	mp->mnt_flag |= MNT_ROOTFS;
226 
227 	/* do our best to set rootdev */
228 	if ((devname[0] != 0) && setrootbyname(devname))
229 		printf("setrootbyname failed\n");
230 
231 	/* If the root device is a type "memory disk", mount RW */
232 	if (rootdev != NODEV && dev_is_good(rootdev) &&
233 	    (dev_dflags(rootdev) & D_MEMDISK)) {
234 		mp->mnt_flag &= ~MNT_RDONLY;
235 	}
236 
237 	error = VFS_MOUNT(mp, NULL, NULL, td);
238 
239 done:
240 	if (vfsname != NULL)
241 		free(vfsname, M_MOUNT);
242 	if (devname != NULL)
243 		free(devname, M_MOUNT);
244 	if (error != 0) {
245 		if (mp != NULL) {
246 			vfs_unbusy(mp, td);
247 			free(mp, M_MOUNT);
248 		}
249 		printf("Root mount failed: %d\n", error);
250 	} else {
251 		/* register with list of mounted filesystems */
252 		mountlist_insert(mp, MNTINS_FIRST);
253 
254 		/* sanity check system clock against root fs timestamp */
255 		inittodr(mp->mnt_time);
256 		vfs_unbusy(mp, td);
257 	}
258 	return(error);
259 }
260 
261 /*
262  * Spin prompting on the console for a suitable root filesystem
263  */
264 static int
265 vfs_mountroot_ask(void)
266 {
267 	char name[128];
268 	int i;
269 	dev_t dev;
270 
271 	for(;;) {
272 		printf("\nManual root filesystem specification:\n");
273 		printf("  <fstype>:<device>  Mount <device> using filesystem <fstype>\n");
274 		printf("                       eg. ufs:da0s1a\n");
275 		printf("  ?                  List valid disk boot devices\n");
276 		printf("  <empty line>       Abort manual input\n");
277 		printf("\nmountroot> ");
278 		gets(name);
279 		if (name[0] == 0)
280 			return(1);
281 		if (name[0] == '?') {
282 			printf("Possibly valid devices for 'ufs' root:\n");
283 			for (i = 0; i < NUMCDEVSW; i++) {
284 				dev = udev2dev(makeudev(i, 0), 0);
285 				if (dev_is_good(dev))
286 					printf(" \"%s\"", dev_dname(dev));
287 			}
288 			printf("\n");
289 			continue;
290 		}
291 		if (!vfs_mountroot_try(name))
292 			return(0);
293 	}
294 }
295 
296 static void
297 gets(char *cp)
298 {
299 	char *lp;
300 	int c;
301 
302 	lp = cp;
303 	for (;;) {
304 		printf("%c", c = cngetc() & 0177);
305 		switch (c) {
306 		case -1:
307 		case '\n':
308 		case '\r':
309 			*lp++ = '\0';
310 			return;
311 		case '\b':
312 		case '\177':
313 			if (lp > cp) {
314 				printf(" \b");
315 				lp--;
316 			}
317 			continue;
318 		case '#':
319 			lp--;
320 			if (lp < cp)
321 				lp = cp;
322 			continue;
323 		case '@':
324 		case 'u' & 037:
325 			lp = cp;
326 			printf("%c", '\n');
327 			continue;
328 		default:
329 			*lp++ = c;
330 		}
331 	}
332 }
333 
334 /*
335  * Convert a given name to the dev_t of the disk-like device
336  * it refers to.
337  */
338 dev_t
339 getdiskbyname(const char *name)
340 {
341 	char *cp;
342 	int nlen;
343 	int cd, unit, slice, part;
344 	dev_t dev;
345 	dev_t rdev;
346 
347 	/*
348 	 * Get the base name of the device
349 	 */
350 	if (strncmp(name, __SYS_PATH_DEV, sizeof(__SYS_PATH_DEV) - 1) == 0)
351 		name += sizeof(__SYS_PATH_DEV) - 1;
352 	cp = __DECONST(char *, name);
353 	while (*cp == '/')
354 		++cp;
355 	while (*cp >= 'a' && *cp <= 'z')
356 		++cp;
357 	if (cp == name) {
358 		printf("missing device name\n");
359 		return (NODEV);
360 	}
361 	nlen = cp - name;
362 
363 	/*
364 	 * Get the unit.
365 	 */
366 	unit = strtol(cp, &cp, 10);
367 	if (name + nlen == (const char *)cp || unit < 0 || unit > DKMAXUNIT) {
368 		printf("bad unit: %d\n", unit);
369 		return (NODEV);
370 	}
371 
372 	/*
373 	 * Get the slice.  Note that if no partition or partition 'a' is
374 	 * specified, and no slice is specified, we will try both 'ad0a'
375 	 * (which is what you get when slice is 0), and also 'ad0' (the
376 	 * whole-disk partition, slice == 1).
377 	 */
378 	if (*cp == 's') {
379 		slice = cp[1] - '0';
380 		if (slice < 1 || slice > 9) {
381 			printf("bad slice number\n");
382 			return(NODEV);
383 		}
384 		++slice;	/* slice #1 starts at 2 */
385 		cp += 2;
386 	} else {
387 		slice = 0;
388 	}
389 
390 	/*
391 	 * Get the partition.
392 	 */
393 	if (*cp >= 'a' && *cp <= 'p') {
394 		part = *cp - 'a';
395 		++cp;
396 	} else {
397 		part = 0;
398 	}
399 
400 	if (*cp != '\0') {
401 		printf("junk after name\n");
402 		return (NODEV);
403 	}
404 
405 	/*
406 	 * Locate the device
407 	 */
408 	for (cd = 0; cd < NUMCDEVSW; cd++) {
409 		const char *dname;
410 
411 		dev = udev2dev(makeudev(cd, dkmakeminor(unit, slice, part)), 0);
412 		if (dev_is_good(dev) && (dname = dev_dname(dev)) != NULL) {
413 			if (strlen(dname) == nlen &&
414 			    strncmp(dname, name, nlen) == 0) {
415 				break;
416 			}
417 		}
418 	}
419 	if (cd == NUMCDEVSW) {
420 		printf("no such device '%*.*s'\n", nlen, nlen, name);
421 		return (NODEV);
422 	}
423 
424 	/*
425 	 * FOUND DEVICE
426 	 */
427 	rdev = make_sub_dev(dev, dkmakeminor(unit, slice, part));
428 	return(rdev);
429 }
430 
431 /*
432  * Set rootdev to match (name), given that we expect it to
433  * refer to a disk-like device.
434  */
435 static int
436 setrootbyname(char *name)
437 {
438 	dev_t diskdev;
439 
440 	diskdev = getdiskbyname(name);
441 	if (diskdev != NODEV) {
442 		rootdev = diskdev;
443 		return (0);
444 	}
445 
446 	return (1);
447 }
448 
449 #ifdef DDB
450 DB_SHOW_COMMAND(disk, db_getdiskbyname)
451 {
452 	dev_t dev;
453 
454 	if (modif[0] == '\0') {
455 		db_error("usage: show disk/devicename");
456 		return;
457 	}
458 	dev = getdiskbyname(modif);
459 	if (dev != NODEV)
460 		db_printf("dev_t = %p\n", dev);
461 	else
462 		db_printf("No disk device matched.\n");
463 }
464 #endif
465