bsd/kern/imageboot.c

   1 /*
   2  * Copyright (c) 2006 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28
  29 #include <sys/param.h>
  30 #include <sys/kernel.h>
  31 #include <sys/proc_internal.h>
  32 #include <sys/systm.h>
  33 #include <sys/systm.h>
  34 #include <sys/mount_internal.h>
  35 #include <sys/filedesc.h>
  36 #include <sys/vnode_internal.h>
  37 #include <sys/imageboot.h>
  38
  39 #include <pexpert/pexpert.h>
  40
  41 extern struct filedesc filedesc0;
  42
  43 extern int (*mountroot)(void);
  44 extern char rootdevice[];
  45
  46 #define DEBUG_IMAGEBOOT 0
  47
  48 #if DEBUG_IMAGEBOOT
  49 #define DBG_TRACE(...) printf(__VA_ARGS__)
  50 #else
  51 #define DBG_TRACE(...) do {} while(0)
  52 #endif
  53
  54 extern int di_root_image(const char *path, char devname[], dev_t *dev_p);
  55
  56 #define kIBFilePrefix "file://"
  57
  58 int
  59 imageboot_needed(void)
  60 {
  61         int result = 0;
  62         char *root_path = NULL;
  63
  64         DBG_TRACE("%s: checking for presence of root path\n", __FUNCTION__);
  65
  66         MALLOC_ZONE(root_path, caddr_t, MAXPATHLEN, M_NAMEI, M_WAITOK);
  67         if (root_path == NULL)
  68                 panic("%s: M_NAMEI zone exhausted", __FUNCTION__);
  69
  70         if(PE_parse_boot_argn("rp", root_path, MAXPATHLEN) == TRUE) {
  71                 /* Got it, now verify scheme */
  72
  73                 if (strncmp(root_path, kIBFilePrefix,
  74                                         strlen(kIBFilePrefix)) == 0) {
  75                         DBG_TRACE("%s: Found %s\n", __FUNCTION__, root_path);
  76                         result = 1;
  77                 } else {
  78                         DBG_TRACE("%s: Invalid URL scheme for %s\n",
  79                                         __FUNCTION__, root_path);
  80                 }
  81         }
  82         FREE_ZONE(root_path, MAXPATHLEN, M_NAMEI);
  83
  84         return (result);
  85 }
  86
  87
  88 /*
  89  * We know there's an image. Attach it, and
  90  * switch over to root off it
  91  *
  92  * NB: p is always kernproc
  93  */
  94
  95 int
  96 imageboot_setup()
  97 {
  98         dev_t       dev;
  99         int         error = 0;
 100         char *root_path = NULL;
 101
 102         DBG_TRACE("%s: entry\n", __FUNCTION__);
 103
 104         MALLOC_ZONE(root_path, caddr_t, MAXPATHLEN, M_NAMEI, M_WAITOK);
 105         if (root_path == NULL)
 106                 return (ENOMEM);
 107
 108         if(PE_parse_boot_argn("rp", root_path, MAXPATHLEN) == FALSE) {
 109                 error = ENOENT;
 110                 goto done;
 111         }
 112
 113         printf("%s: root image url is %s\n", __FUNCTION__, root_path);
 114         error = di_root_image(root_path, rootdevice, &dev);
 115         if(error) {
 116                 printf("%s: di_root_image failed: %d\n", __FUNCTION__, error);
 117                 goto done;
 118         }
 119
 120         rootdev = dev;
 121         mountroot = NULL;
 122         printf("%s: root device 0x%x\n", __FUNCTION__, rootdev);
 123         error = vfs_mountroot();
 124
 125         if (error == 0 && rootvnode != NULL) {
 126                 struct vnode *tvp;
 127                 struct vnode *newdp;
 128
 129                 /*
 130                  * Get the vnode for '/'.
 131                  * Set fdp->fd_fd.fd_cdir to reference it.
 132                  */
 133                 if (VFS_ROOT(TAILQ_LAST(&mountlist,mntlist), &newdp, vfs_context_kernel()))
 134                         panic("%s: cannot find root vnode", __FUNCTION__);
 135
 136                 vnode_ref(newdp);
 137                 vnode_put(newdp);
 138                 tvp = rootvnode;
 139                 vnode_rele(tvp);
 140                 filedesc0.fd_cdir = newdp;
 141                 rootvnode = newdp;
 142                 mount_list_lock();
 143                 TAILQ_REMOVE(&mountlist, TAILQ_FIRST(&mountlist), mnt_list);
 144                 mount_list_unlock();
 145                 mountlist.tqh_first->mnt_flag |= MNT_ROOTFS;
 146                 DBG_TRACE("%s: root switched\n", __FUNCTION__);
 147         }
 148 done:
 149         FREE_ZONE(root_path, MAXPATHLEN, M_NAMEI);
 150
 151         DBG_TRACE("%s: exit\n", __FUNCTION__);
 152
 153         return (error);
 154 }