vfs_mount.c revision 52886
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 52886 1999-11-05 02:45:50Z msmith $ 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 = path = mp = NULL; 171 error = EINVAL; 172 173 if (mountfrom == NULL) 174 goto done; 175 176 printf("Mounting root from %s\n", mountfrom); 177 178 /* parse vfs name and path */ 179 vfsname = malloc(MFSNAMELEN, M_MOUNT, M_WAITOK); 180 path = malloc(MNAMELEN, M_MOUNT, M_WAITOK); 181 vfsname[0] = path[0] = 0; 182 sprintf(patt, "%%%d[a-z0-9]:%%%ds", MFSNAMELEN, MNAMELEN); 183 if (sscanf(mountfrom, patt, vfsname, path) < 1) 184 goto done; 185 186 /* allocate a root mount */ 187 if ((error = vfs_rootmountalloc(vfsname, ROOTNAME, &mp))) { 188 printf("Can't allocate root mount for filesystem '%s': %d\n", 189 vfsname, error); 190 goto done; 191 } 192 mp->mnt_flag |= MNT_ROOTFS; 193 194 /* do our best to set rootdev */ 195 if ((path[0] != 0) && setrootbyname(path)) 196 printf("setrootbyname failed\n"); 197 198 strcpy(mp->mnt_stat.f_mntfromname, path); 199 error = VFS_MOUNT(mp, NULL, NULL, NULL, curproc); 200 201done: 202 free(vfsname, M_MOUNT); 203 free(path, M_MOUNT); 204 if (error != 0) { 205 if (mp != NULL) 206 free(mp, M_MOUNT); 207 printf("Root mount failed: %d\n", error); 208 } else { 209 210 /* register with list of mounted filesystems */ 211 simple_lock(&mountlist_slock); 212 CIRCLEQ_INSERT_HEAD(&mountlist, mp, mnt_list); 213 simple_unlock(&mountlist_slock); 214 215 /* sanity check system clock against root filesystem timestamp */ 216 inittodr(mp->mnt_time); 217 } 218 if (mp != NULL) 219 vfs_unbusy(mp, curproc); 220 return(error); 221} 222 223/* 224 * Spin prompting on the console for a suitable root filesystem 225 */ 226static int 227vfs_mountroot_ask(void) 228{ 229 char name[128]; 230 int i; 231 dev_t dev; 232 233 for(;;) { 234 printf("\nManual root filesystem specification:\n"); 235 printf(" <fstype>:<device> Mount <device> using filesystem <fstype>\n"); 236 printf(" eg. ufs:/dev/da0s1a\n"); 237 printf(" ? List valid disk boot devices\n"); 238 printf(" <empty line> Abort manual input\n"); 239 printf("\n>>> "); 240 gets(name); 241 if (name[0] == 0) 242 return(1); 243 if (name[0] == '?') { 244 printf("Possibly valid devices for 'ufs' root:\n"); 245 for (i = 0; i < NUMCDEVSW; i++) { 246 dev = makebdev(i, 0); 247 if (devsw(dev) != NULL) 248 printf(" \"%s\"", devsw(dev)->d_name); 249 } 250 printf("\n"); 251 continue; 252 } 253 if (!vfs_mountroot_try(name)) 254 return(0); 255 } 256} 257 258static void 259gets(char *cp) 260{ 261 char *lp; 262 int c; 263 264 lp = cp; 265 for (;;) { 266 printf("%c", c = cngetc() & 0177); 267 switch (c) { 268 case -1: 269 case '\n': 270 case '\r': 271 *lp++ = '\0'; 272 return; 273 case '\b': 274 case '\177': 275 if (lp > cp) { 276 printf(" \b"); 277 lp--; 278 } 279 continue; 280 case '#': 281 lp--; 282 if (lp < cp) 283 lp = cp; 284 continue; 285 case '@': 286 case 'u' & 037: 287 lp = cp; 288 printf("%c", '\n'); 289 continue; 290 default: 291 *lp++ = c; 292 } 293 } 294} 295 296/* 297 * Set rootdev to match (name), given that we expect it to 298 * refer to a disk-like device. 299 */ 300static int 301setrootbyname(char *name) 302{ 303 char *cp; 304 int bd, unit, slice, part; 305 dev_t dev; 306 307 slice = 0; 308 part = 0; 309 cp = rindex(name, '/'); 310 if (cp != NULL) { 311 name = cp + 1; 312 } 313 cp = name; 314 while (cp != '\0' && (*cp < '0' || *cp > '9')) 315 cp++; 316 if (cp == name) { 317 printf("missing device name\n"); 318 return(1); 319 } 320 if (*cp == '\0') { 321 printf("missing unit number\n"); 322 return(1); 323 } 324 unit = *cp - '0'; 325 *cp++ = '\0'; 326 for (bd = 0; bd < NUMCDEVSW; bd++) { 327 dev = makebdev(bd, 0); 328 if (devsw(dev) != NULL && 329 strcmp(devsw(dev)->d_name, name) == 0) 330 goto gotit; 331 } 332 printf("no such device '%s'\n", name); 333 return (2); 334gotit: 335 while (*cp >= '0' && *cp <= '9') 336 unit += 10 * unit + *cp++ - '0'; 337 if (*cp == 's' && cp[1] >= '0' && cp[1] <= '9') { 338 slice = cp[1] - '0' + 1; 339 cp += 2; 340 } 341 if (*cp >= 'a' && *cp <= 'h') { 342 part = *cp - 'a'; 343 cp++; 344 } 345 if (*cp != '\0') { 346 printf("junk after name\n"); 347 return (1); 348 } 349 rootdev = makebdev(bd, dkmakeminor(unit, slice, part)); 350 return 0; 351} 352 353