xnu-1228.tar.gz

[apple/xnu.git] / bsd / kern / imageboot.c

diff --git a/bsd/kern/imageboot.c b/bsd/kern/imageboot.c
new file mode 100644 (file)
index 0000000..8af10ca
--- /dev/null
+++ b/bsd/kern/imageboot.c
@@ -0,0 +1,154 @@
+/*
+ * Copyright (c) 2006 Apple Computer, Inc. All rights reserved.
+ *
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
+ * 
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. The rights granted to you under the License
+ * may not be used to create, or enable the creation or redistribution of,
+ * unlawful or unlicensed copies of an Apple operating system, or to
+ * circumvent, violate, or enable the circumvention or violation of, any
+ * terms of an Apple operating system software license agreement.
+ * 
+ * Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this file.
+ * 
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
+ * 
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
+ */
+
+#include <sys/param.h>
+#include <sys/kernel.h>
+#include <sys/proc_internal.h>
+#include <sys/systm.h>
+#include <sys/systm.h>
+#include <sys/mount_internal.h>
+#include <sys/filedesc.h>
+#include <sys/vnode_internal.h>
+#include <sys/imageboot.h>
+
+#include <pexpert/pexpert.h>
+
+extern struct filedesc filedesc0;
+
+extern int (*mountroot)(void);
+extern char rootdevice[];
+
+#define DEBUG_IMAGEBOOT 0
+
+#if DEBUG_IMAGEBOOT
+#define DBG_TRACE(...) printf(__VA_ARGS__)
+#else
+#define DBG_TRACE(...) do {} while(0)
+#endif
+
+extern int di_root_image(const char *path, char devname[], dev_t *dev_p);
+
+#define kIBFilePrefix "file://"
+
+int
+imageboot_needed(void)
+{
+       int result = 0;
+       char *root_path = NULL;
+
+       DBG_TRACE("%s: checking for presence of root path\n", __FUNCTION__);
+
+       MALLOC_ZONE(root_path, caddr_t, MAXPATHLEN, M_NAMEI, M_WAITOK);
+       if (root_path == NULL)
+               panic("%s: M_NAMEI zone exhausted", __FUNCTION__);
+
+       if(PE_parse_boot_arg("rp", root_path) == TRUE) {
+               /* Got it, now verify scheme */
+
+               if (strncmp(root_path, kIBFilePrefix,
+                                       strlen(kIBFilePrefix)) == 0) {
+                       DBG_TRACE("%s: Found %s\n", __FUNCTION__, root_path);
+                       result = 1;
+               } else {
+                       DBG_TRACE("%s: Invalid URL scheme for %s\n",
+                                       __FUNCTION__, root_path);
+               }
+       }
+       FREE_ZONE(root_path, MAXPATHLEN, M_NAMEI);
+
+       return (result);
+}
+
+
+/*
+ * We know there's an image. Attach it, and
+ * switch over to root off it
+ *
+ * NB: p is always kernproc
+ */
+
+int
+imageboot_setup()
+{
+       dev_t       dev;
+       int         error = 0;
+       char *root_path = NULL;
+
+       DBG_TRACE("%s: entry\n", __FUNCTION__);
+
+       MALLOC_ZONE(root_path, caddr_t, MAXPATHLEN, M_NAMEI, M_WAITOK);
+       if (root_path == NULL)
+               return (ENOMEM);
+
+       if(PE_parse_boot_arg("rp", root_path) == FALSE) {
+               error = ENOENT;
+               goto done;
+       }
+
+       printf("%s: root image url is %s\n", __FUNCTION__, root_path);
+       error = di_root_image(root_path, rootdevice, &dev);
+       if(error) {
+               printf("%s: di_root_image failed: %d\n", __FUNCTION__, error);
+               goto done;
+       }
+
+       rootdev = dev;
+       mountroot = NULL;
+       printf("%s: root device 0x%x\n", __FUNCTION__, rootdev);
+       error = vfs_mountroot();
+
+       if (error == 0 && rootvnode != NULL) {
+               struct vnode *tvp;
+               struct vnode *newdp;
+
+               /*
+                * Get the vnode for '/'.
+                * Set fdp->fd_fd.fd_cdir to reference it.
+                */
+               if (VFS_ROOT(TAILQ_LAST(&mountlist,mntlist), &newdp, vfs_context_kernel()))
+                       panic("%s: cannot find root vnode", __FUNCTION__);
+
+               vnode_ref(newdp);
+               vnode_put(newdp);
+               tvp = rootvnode;
+               vnode_rele(tvp);
+               filedesc0.fd_cdir = newdp;
+               rootvnode = newdp;
+               mount_list_lock();
+               TAILQ_REMOVE(&mountlist, TAILQ_FIRST(&mountlist), mnt_list);
+               mount_list_unlock();
+               mountlist.tqh_first->mnt_flag |= MNT_ROOTFS;
+               DBG_TRACE("%s: root switched\n", __FUNCTION__);
+       }
+done:
+       FREE_ZONE(root_path, MAXPATHLEN, M_NAMEI);
+
+       DBG_TRACE("%s: exit\n", __FUNCTION__);
+
+       return (error);
+}