vfs_mount.c revision 53888
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: head/sys/kern/vfs_mount.c 53888 1999-11-29 18:51:04Z dillon $ 29 */ 30 31/* 32 * Locate and mount the root filesystem. 33 * 34 * The root filesystem is detailed in the kernel environment variable 35 * vfs.root.mountfrom, which is expected to be in the general format 36 * 37 * <vfsname>:[<path>] 38 * vfsname := the name of a VFS known to the kernel and capable 39 * of being mounted as root 40 * path := disk device name or other data used by the filesystem 41 * to locate its physical store 42 * 43 */ 44 45#include <sys/param.h> 46#include <sys/kernel.h> 47#include <sys/systm.h> 48#include <sys/proc.h> 49#include <sys/vnode.h> 50#include <sys/mount.h> 51#include <sys/malloc.h> 52#include <sys/reboot.h> 53#include <sys/diskslice.h> 54#include <sys/disklabel.h> 55#include <sys/conf.h> 56#include <sys/cons.h> 57 58MALLOC_DEFINE(M_MOUNT, "mount", "vfs mount structure"); 59 60#define ROOTNAME "root_device" 61 62struct vnode *rootvnode; 63 64/* 65 * The root specifiers we will try if RB_CDROM is specified. 66 */ 67static char *cdrom_rootdevnames[] = { 68 "cd9660:cd0a", 69 "cd9660:acd0a", 70 "cd9660:wcd0a", 71 NULL 72}; 73 74static void vfs_mountroot(void *junk); 75static int vfs_mountroot_try(char *mountfrom); 76static int vfs_mountroot_ask(void); 77static void gets(char *cp); 78 79/* legacy find-root code */ 80char *rootdevnames[2] = {NULL, NULL}; 81static int setrootbyname(char *name); 82 83SYSINIT(mountroot, SI_SUB_MOUNT_ROOT, SI_ORDER_SECOND, vfs_mountroot, NULL); 84 85/* 86 * Find and mount the root filesystem 87 */ 88static void 89vfs_mountroot(void *junk) 90{ 91 int i; 92 93 /* 94 * The root filesystem information is compiled in, and we are 95 * booted with instructions to use it. 96 */ 97#ifdef ROOTDEVNAME 98 if ((boothowto & RB_DFLTROOT) && 99 !vfs_mountroot_try(ROOTDEVNAME)) 100 return; 101#endif 102 /* 103 * We are booted with instructions to prompt for the root filesystem, 104 * or to use the compiled-in default when it doesn't exist. 105 */ 106 if (boothowto & (RB_DFLTROOT | RB_ASKNAME)) { 107 if (!vfs_mountroot_ask()) 108 return; 109 } 110 111 /* 112 * We've been given the generic "use CDROM as root" flag. This is 113 * necessary because one media may be used in many different 114 * devices, so we need to search for them. 115 */ 116 if (boothowto & RB_CDROM) { 117 for (i = 0; cdrom_rootdevnames[i] != NULL; i++) { 118 if (!vfs_mountroot_try(cdrom_rootdevnames[i])) 119 return; 120 } 121 } 122 123 /* 124 * Try to use the value read by the loader from /etc/fstab, or 125 * supplied via some other means. This is the preferred 126 * mechanism. 127 */ 128 if (!vfs_mountroot_try(getenv("vfs.root.mountfrom"))) 129 return; 130 131 /* 132 * Try values that may have been computed by the machine-dependant 133 * legacy code. 134 */ 135 if (!vfs_mountroot_try(rootdevnames[0])) 136 return; 137 if (!vfs_mountroot_try(rootdevnames[1])) 138 return; 139 140 /* 141 * If we have a compiled-in default, and haven't already tried it, try 142 * it now. 143 */ 144#ifdef ROOTDEVNAME 145 if (!(boothowto & RB_DFLTROOT)) 146 if (!vfs_mountroot_try(ROOTDEVNAME)) 147 return; 148#endif 149 150 /* 151 * Everything so far has failed, prompt on the console if we haven't 152 * already tried that. 153 */ 154 if (!(boothowto & (RB_DFLTROOT | RB_ASKNAME)) && !vfs_mountroot_ask()) 155 return; 156 panic("Root mount failed, startup aborted."); 157} 158 159/* 160 * Mount (mountfrom) as the root filesystem. 161 */ 162static int 163vfs_mountroot_try(char *mountfrom) 164{ 165 struct mount *mp; 166 char *vfsname, *path; 167 int error; 168 char patt[32]; 169 170 vfsname = NULL; 171 path = NULL; 172 mp = NULL; 173 error = EINVAL; 174 175 if (mountfrom == NULL) 176 return(error); /* don't complain */ 177 178 printf("Mounting root from %s\n", mountfrom); 179 180 /* parse vfs name and path */ 181 vfsname = malloc(MFSNAMELEN, M_MOUNT, M_WAITOK); 182 path = malloc(MNAMELEN, M_MOUNT, M_WAITOK); 183 vfsname[0] = path[0] = 0; 184 sprintf(patt, "%%%d[a-z0-9]:%%%ds", MFSNAMELEN, MNAMELEN); 185 if (sscanf(mountfrom, patt, vfsname, path) < 1) 186 goto done; 187 188 /* allocate a root mount */ 189 error = vfs_rootmountalloc(vfsname, path[0] != 0 ? path : ROOTNAME, 190 &mp); 191 if (error != 0) { 192 printf("Can't allocate root mount for filesystem '%s': %d\n", 193 vfsname, error); 194 goto done; 195 } 196 mp->mnt_flag |= MNT_ROOTFS; 197 198 /* do our best to set rootdev */ 199 if ((path[0] != 0) && setrootbyname(path)) 200 printf("setrootbyname failed\n"); 201 202 /* If the root device is a type "memory disk", mount RW */ 203 if (rootdev != NODEV && devsw(rootdev) && (devsw(rootdev)->d_flags & D_MEMDISK)) 204 mp->mnt_flag &= ~MNT_RDONLY; 205 206 error = VFS_MOUNT(mp, NULL, NULL, NULL, curproc); 207 208done: 209 if (vfsname != NULL) 210 free(vfsname, M_MOUNT); 211 if (path != NULL) 212 free(path, M_MOUNT); 213 if (error != 0) { 214 if (mp != NULL) { 215 vfs_unbusy(mp, curproc); 216 free(mp, M_MOUNT); 217 } 218 printf("Root mount failed: %d\n", error); 219 } else { 220 221 /* register with list of mounted filesystems */ 222 simple_lock(&mountlist_slock); 223 TAILQ_INSERT_HEAD(&mountlist, mp, mnt_list); 224 simple_unlock(&mountlist_slock); 225 226 /* sanity check system clock against root filesystem timestamp */ 227 inittodr(mp->mnt_time); 228 vfs_unbusy(mp, curproc); 229 } 230 return(error); 231} 232 233/* 234 * Spin prompting on the console for a suitable root filesystem 235 */ 236static int 237vfs_mountroot_ask(void) 238{ 239 char name[128]; 240 int i; 241 dev_t dev; 242 243 for(;;) { 244 printf("\nManual root filesystem specification:\n"); 245 printf(" <fstype>:<device> Mount <device> using filesystem <fstype>\n"); 246 printf(" eg. ufs:/dev/da0s1a\n"); 247 printf(" ? List valid disk boot devices\n"); 248 printf(" <empty line> Abort manual input\n"); 249 printf("\n>>> "); 250 gets(name); 251 if (name[0] == 0) 252 return(1); 253 if (name[0] == '?') { 254 printf("Possibly valid devices for 'ufs' root:\n"); 255 for (i = 0; i < NUMCDEVSW; i++) { 256 dev = makebdev(i, 0); 257 if (devsw(dev) != NULL) 258 printf(" \"%s\"", devsw(dev)->d_name); 259 } 260 printf("\n"); 261 continue; 262 } 263 if (!vfs_mountroot_try(name)) 264 return(0); 265 } 266} 267 268static void 269gets(char *cp) 270{ 271 char *lp; 272 int c; 273 274 lp = cp; 275 for (;;) { 276 printf("%c", c = cngetc() & 0177); 277 switch (c) { 278 case -1: 279 case '\n': 280 case '\r': 281 *lp++ = '\0'; 282 return; 283 case '\b': 284 case '\177': 285 if (lp > cp) { 286 printf(" \b"); 287 lp--; 288 } 289 continue; 290 case '#': 291 lp--; 292 if (lp < cp) 293 lp = cp; 294 continue; 295 case '@': 296 case 'u' & 037: 297 lp = cp; 298 printf("%c", '\n'); 299 continue; 300 default: 301 *lp++ = c; 302 } 303 } 304} 305 306/* 307 * Set rootdev to match (name), given that we expect it to 308 * refer to a disk-like device. 309 */ 310static int 311setrootbyname(char *name) 312{ 313 char *cp; 314 int bd, unit, slice, part; 315 dev_t dev; 316 317 slice = 0; 318 part = 0; 319 cp = rindex(name, '/'); 320 if (cp != NULL) { 321 name = cp + 1; 322 } 323 cp = name; 324 while (cp != '\0' && (*cp < '0' || *cp > '9')) 325 cp++; 326 if (cp == name) { 327 printf("missing device name\n"); 328 return(1); 329 } 330 if (*cp == '\0') { 331 printf("missing unit number\n"); 332 return(1); 333 } 334 unit = *cp - '0'; 335 *cp++ = '\0'; 336 for (bd = 0; bd < NUMCDEVSW; bd++) { 337 dev = makebdev(bd, 0); 338 if (devsw(dev) != NULL && 339 strcmp(devsw(dev)->d_name, name) == 0) 340 goto gotit; 341 } 342 printf("no such device '%s'\n", name); 343 return (2); 344gotit: 345 while (*cp >= '0' && *cp <= '9') 346 unit += 10 * unit + *cp++ - '0'; 347 if (*cp == 's' && cp[1] >= '0' && cp[1] <= '9') { 348 slice = cp[1] - '0' + 1; 349 cp += 2; 350 } 351 if (*cp >= 'a' && *cp <= 'h') { 352 part = *cp - 'a'; 353 cp++; 354 } 355 if (*cp != '\0') { 356 printf("junk after name\n"); 357 return (1); 358 } 359 rootdev = makebdev(bd, dkmakeminor(unit, slice, part)); 360 return 0; 361} 362 363