From 46077e846b0bcee3bda14b3650a2f4be79568826 Mon Sep 17 00:00:00 2001
From: Alex Hornung <ahornung@gmail.com>
Date: Sun, 14 Mar 2010 08:27:32 +0000
Subject: [PATCH] nlookup - introduce nlookup_init_root

* nlookup_init_root is similar to nlookup_init_raw, but does not assume
  rootnch is set already, but rather has one more parameter which
  specifies the root nch.
---
 sys/kern/vfs_nlookup.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
 sys/sys/nlookup.h      |  1 +
 2 files changed, 45 insertions(+)

diff --git a/sys/kern/vfs_nlookup.c b/sys/kern/vfs_nlookup.c
index f7377b0918..9d9f22eafd 100644
--- a/sys/kern/vfs_nlookup.c
+++ b/sys/kern/vfs_nlookup.c
@@ -230,6 +230,50 @@ nlookup_init_raw(struct nlookupdata *nd,
 }
 
 /*
+ * This works similarly to nlookup_init_raw() but does not rely
+ * on rootnch being initialized yet.
+ */
+int
+nlookup_init_root(struct nlookupdata *nd, 
+	     const char *path, enum uio_seg seg, int flags,
+	     struct ucred *cred, struct nchandle *ncstart,
+	     struct nchandle *ncroot)
+{
+    size_t pathlen;
+    thread_t td;
+    int error;
+
+    td = curthread;
+
+    bzero(nd, sizeof(struct nlookupdata));
+    nd->nl_path = objcache_get(namei_oc, M_WAITOK);
+    nd->nl_flags |= NLC_HASBUF;
+    if (seg == UIO_SYSSPACE) 
+	error = copystr(path, nd->nl_path, MAXPATHLEN, &pathlen);
+    else
+	error = copyinstr(path, nd->nl_path, MAXPATHLEN, &pathlen);
+
+    /*
+     * Don't allow empty pathnames.
+     * POSIX.1 requirement: "" is not a vaild file name.
+     */
+    if (error == 0 && pathlen <= 1)
+	error = ENOENT;
+
+    if (error == 0) {
+	cache_copy(ncstart, &nd->nl_nch);
+	cache_copy(ncroot, &nd->nl_rootnch);
+	cache_copy(ncroot, &nd->nl_jailnch);
+	nd->nl_cred = crhold(cred);
+	nd->nl_td = td;
+	nd->nl_flags |= flags;
+    } else {
+	nlookup_done(nd);
+    }
+    return(error);
+}
+
+/*
  * Set a different credential; this credential will be used by future
  * operations performed on nd.nl_open_vp and nlookupdata structure.
  */
diff --git a/sys/sys/nlookup.h b/sys/sys/nlookup.h
index 29eb7d3176..d058174792 100644
--- a/sys/sys/nlookup.h
+++ b/sys/sys/nlookup.h
@@ -150,6 +150,7 @@ int nlookup_init(struct nlookupdata *, const char *, enum uio_seg, int);
 int nlookup_init_at(struct nlookupdata *, struct file **, int, const char *, 
 		enum uio_seg, int);
 int nlookup_init_raw(struct nlookupdata *, const char *, enum uio_seg, int, struct ucred *, struct nchandle *);
+int nlookup_init_root(struct nlookupdata *, const char *, enum uio_seg, int, struct ucred *, struct nchandle *, struct nchandle *);
 void nlookup_set_cred(struct nlookupdata *nd, struct ucred *cred);
 void nlookup_zero(struct nlookupdata *);
 void nlookup_done(struct nlookupdata *);
-- 
2.11.4.GIT