xnu-2782.30.5.tar.gz

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

diff --git a/bsd/kern/imageboot.c b/bsd/kern/imageboot.c
index 6325962b2cfe1fc2b08c0ec248822361a30fffec..9fa89e44315a16552add539388182f767683de18 100644 (file)
--- a/bsd/kern/imageboot.c
+++ b/bsd/kern/imageboot.c
@@ -35,6 +35,7 @@
 #include <sys/filedesc.h>
 #include <sys/vnode_internal.h>
 #include <sys/imageboot.h>
 #include <sys/filedesc.h>
 #include <sys/vnode_internal.h>
 #include <sys/imageboot.h>

+#include <kern/assert.h>

 
 #include <pexpert/pexpert.h>
 
 
 #include <pexpert/pexpert.h>
 


@@ -52,33 +53,68 @@ extern char rootdevice[];
 #endif
 
 extern int di_root_image(const char *path, char devname[], dev_t *dev_p);
 #endif
 
 extern int di_root_image(const char *path, char devname[], dev_t *dev_p);

+static boolean_t imageboot_setup_new(void);

 
 #define kIBFilePrefix "file://"
 
 
 #define kIBFilePrefix "file://"
 

-int
+__private_extern__ int
+imageboot_format_is_valid(const char *root_path)
+{
+       return (strncmp(root_path, kIBFilePrefix,
+                               strlen(kIBFilePrefix)) == 0);
+}
+
+static void
+vnode_get_and_drop_always(vnode_t vp) 
+{
+       vnode_getalways(vp);
+       vnode_rele(vp);
+       vnode_put(vp);
+}
+
+__private_extern__ int

 imageboot_needed(void)
 {
        int result = 0;
        char *root_path = NULL;
 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__);
 
        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_argn("rp", root_path, MAXPATHLEN) == TRUE) {
-               /* Got it, now verify scheme */
+       /* Check for first layer */
+       if (!(PE_parse_boot_argn("rp0", root_path, MAXPATHLEN) || 
+                       PE_parse_boot_argn("rp", root_path, MAXPATHLEN) ||
+                       PE_parse_boot_argn(IMAGEBOOT_ROOT_ARG, root_path, MAXPATHLEN))) {
+               goto out;
+       }
+       
+       /* Sanity-check first layer */
+       if (imageboot_format_is_valid(root_path)) {
+               DBG_TRACE("%s: Found %s\n", __FUNCTION__, root_path);
+       } else {
+               goto out;
+       }
+
+       result = 1;

 
 

-               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);
-               }
+       /* Check for second layer */
+       if (!(PE_parse_boot_argn("rp1", root_path, MAXPATHLEN) ||
+                       PE_parse_boot_argn(IMAGEBOOT_CONTAINER_ARG, root_path, MAXPATHLEN))) {
+               goto out;

        }
        }

+
+       /* Sanity-check second layer */
+       if (imageboot_format_is_valid(root_path)) {
+               DBG_TRACE("%s: Found %s\n", __FUNCTION__, root_path);
+       } else {
+               panic("%s: Invalid URL scheme for %s\n",
+                               __FUNCTION__, root_path);
+       }
+
+out:

        FREE_ZONE(root_path, MAXPATHLEN, M_NAMEI);
 
        return (result);
        FREE_ZONE(root_path, MAXPATHLEN, M_NAMEI);
 
        return (result);


@@ -86,69 +122,194 @@ imageboot_needed(void)
 
 
 /*
 
 
 /*

- * We know there's an image. Attach it, and
- * switch over to root off it
- *
- * NB: p is always kernproc
+ * Swaps in new root filesystem based on image path.
+ * Current root filesystem is removed from mount list and
+ * tagged MNTK_BACKS_ROOT, MNT_ROOTFS is cleared on it, and 
+ * "rootvnode" is reset.  Root vnode of currentroot filesystem 
+ * is returned with usecount (no iocount).

  */
  */

+__private_extern__ int
+imageboot_mount_image(const char *root_path, int height)
+{
+       dev_t           dev;
+       int             error;
+       vnode_t         old_rootvnode = NULL;
+       vnode_t         newdp;
+       mount_t         new_rootfs;
+
+       error = di_root_image(root_path, rootdevice, &dev);
+       if (error) {
+               panic("%s: di_root_image failed: %d\n", __FUNCTION__, error);
+       }
+
+       rootdev = dev;
+       mountroot = NULL;
+       printf("%s: root device 0x%x\n", __FUNCTION__, rootdev);
+       error = vfs_mountroot();
+       if (error != 0) {
+               panic("vfs_mountroot() failed.\n");
+       }
+
+       /*
+        * 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__);
+
+       if (rootvnode != NULL) {
+               /* remember the old rootvnode, but remove it from mountlist */
+               mount_t         old_rootfs;
+
+               old_rootvnode = rootvnode;
+               old_rootfs = rootvnode->v_mount;
+       
+               mount_list_remove(old_rootfs);
+       
+               mount_lock(old_rootfs);
+#ifdef CONFIG_IMGSRC_ACCESS
+               old_rootfs->mnt_kern_flag |= MNTK_BACKS_ROOT;
+#endif /* CONFIG_IMGSRC_ACCESS */
+               old_rootfs->mnt_flag &= ~MNT_ROOTFS;
+               mount_unlock(old_rootfs);
+       }
+
+       /* switch to the new rootvnode */
+       rootvnode = newdp;
+
+       new_rootfs = rootvnode->v_mount;
+       mount_lock(new_rootfs);
+       new_rootfs->mnt_flag |= MNT_ROOTFS;
+       mount_unlock(new_rootfs);
+
+       vnode_ref(newdp);
+       vnode_put(newdp);
+       filedesc0.fd_cdir = newdp;
+       DBG_TRACE("%s: root switched\n", __FUNCTION__);
+
+       if (old_rootvnode != NULL) {
+#ifdef CONFIG_IMGSRC_ACCESS
+           if (height >= 0 && PE_imgsrc_mount_supported()) {
+               imgsrc_rootvnodes[height] = old_rootvnode;
+           } else {
+               vnode_get_and_drop_always(old_rootvnode);
+           }
+#else 
+           height = 0; /* keep the compiler from complaining */
+           vnode_get_and_drop_always(old_rootvnode);
+#endif /* CONFIG_IMGSRC_ACCESS */
+       }
+       return 0;
+}

 
 

-int
+static boolean_t 
+imageboot_setup_new()
+{
+       int error;
+       char *root_path = NULL;
+       int height = 0;
+       boolean_t done = FALSE;
+
+       MALLOC_ZONE(root_path, caddr_t, MAXPATHLEN, M_NAMEI, M_WAITOK);
+       assert(root_path != NULL);
+
+       if(PE_parse_boot_argn(IMAGEBOOT_CONTAINER_ARG, root_path, MAXPATHLEN) == TRUE) {
+               printf("%s: container image url is %s\n", __FUNCTION__, root_path);
+               error = imageboot_mount_image(root_path, height);
+               if (error != 0) {
+                       panic("Failed to mount container image.");
+               }
+
+               height++;
+       }
+
+       if (PE_parse_boot_argn(IMAGEBOOT_ROOT_ARG, root_path, MAXPATHLEN) == FALSE) {
+               if (height > 0) {
+                       panic("%s specified without %s?\n", IMAGEBOOT_CONTAINER_ARG, IMAGEBOOT_ROOT_ARG);
+               }
+               goto out;
+
+       }
+
+       printf("%s: root image url is %s\n", __FUNCTION__, root_path);
+
+       error = imageboot_mount_image(root_path, height);
+       if (error != 0) {
+               panic("Failed to mount root image.");
+       }
+
+       done = TRUE;
+
+out:
+       FREE_ZONE(root_path, MAXPATHLEN, M_NAMEI);
+       return done;
+}
+
+__private_extern__ void

 imageboot_setup()
 {
 imageboot_setup()
 {

-       dev_t       dev;

        int         error = 0;
        char *root_path = NULL;
 
        DBG_TRACE("%s: entry\n", __FUNCTION__);
 
        int         error = 0;
        char *root_path = NULL;
 
        DBG_TRACE("%s: entry\n", __FUNCTION__);
 

+       if (rootvnode == NULL) {        
+               panic("imageboot_setup: rootvnode is NULL.");
+       }
+
+       /*
+        * New boot-arg scheme:
+        *      root-dmg : the dmg that will be the root filesystem.
+        *      container-dmg : an optional dmg that contains the root-dmg.
+        */
+       if (imageboot_setup_new()) {
+               return;
+       }
+       

        MALLOC_ZONE(root_path, caddr_t, MAXPATHLEN, M_NAMEI, M_WAITOK);
        MALLOC_ZONE(root_path, caddr_t, MAXPATHLEN, M_NAMEI, M_WAITOK);

-       if (root_path == NULL)
-               return (ENOMEM);
+       assert(root_path != NULL);

 
 

-       if(PE_parse_boot_argn("rp", root_path, MAXPATHLEN) == FALSE) {
-               error = ENOENT;
-               goto done;
+       /*
+        * Look for outermost disk image to root from.  If we're doing a nested boot,
+        * there's some sense in which the outer image never needs to be the root filesystem,
+        * but it does need very similar treatment: it must not be unmounted, needs a fake
+        * device vnode created for it, and should not show up in getfsstat() until exposed 
+        * with MNT_IMGSRC. We just make it the temporary root.
+        */
+       if((PE_parse_boot_argn("rp", root_path, MAXPATHLEN) == FALSE) &&
+               (PE_parse_boot_argn("rp0", root_path, MAXPATHLEN) == FALSE)) {
+               panic("%s: no valid path to image.\n", __FUNCTION__);

        }
 
        printf("%s: root image url is %s\n", __FUNCTION__, root_path);
        }
 
        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;
+       
+       error = imageboot_mount_image(root_path, 0);
+       if (error) {
+               panic("Failed on first stage of imageboot.");

        }
 
        }
 

-       rootdev = dev;
-       mountroot = NULL;
-       printf("%s: root device 0x%x\n", __FUNCTION__, rootdev);
-       error = vfs_mountroot();
+       /*
+        * See if we are rooting from a nested image
+        */
+       if(PE_parse_boot_argn("rp1", root_path, MAXPATHLEN) == FALSE) {
+               goto done;
+       }
+       
+       printf("%s: second level root image url is %s\n", __FUNCTION__, root_path);

 
 

-       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__);
+       /*
+        * If we fail to set up second image, it's not a given that we
+        * can safely root off the first.  
+        */
+       error = imageboot_mount_image(root_path, 1);
+       if (error) {
+               panic("Failed on second stage of imageboot.");  

        }
        }

+

 done:
        FREE_ZONE(root_path, MAXPATHLEN, M_NAMEI);
 
        DBG_TRACE("%s: exit\n", __FUNCTION__);
 
 done:
        FREE_ZONE(root_path, MAXPATHLEN, M_NAMEI);
 
        DBG_TRACE("%s: exit\n", __FUNCTION__);
 

-       return (error);
+       return;

 }
 }