[src/trunk]: src/sys/kern Split TRYEMULROOT handling into its own function.

[dholland <dholland%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/ea3eeeb1a857
branches:  trunk
changeset: 764050:ea3eeeb1a857
user:      dholland <dholland%NetBSD.org@localhost>
date:      Mon Apr 11 01:36:59 2011 +0000

description:
Split TRYEMULROOT handling into its own function.

diffstat:

 sys/kern/vfs_lookup.c |  103 ++++++++++++++++++++++++++++++-------------------
 1 files changed, 63 insertions(+), 40 deletions(-)

diffs (183 lines):

diff -r 2f87ad3279f8 -r ea3eeeb1a857 sys/kern/vfs_lookup.c
--- a/sys/kern/vfs_lookup.c     Mon Apr 11 01:36:28 2011 +0000
+++ b/sys/kern/vfs_lookup.c     Mon Apr 11 01:36:59 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: vfs_lookup.c,v 1.136 2011/04/11 01:36:28 dholland Exp $        */
+/*     $NetBSD: vfs_lookup.c,v 1.137 2011/04/11 01:36:59 dholland Exp $        */
 
 /*
  * Copyright (c) 1982, 1986, 1989, 1993
@@ -37,7 +37,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: vfs_lookup.c,v 1.136 2011/04/11 01:36:28 dholland Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vfs_lookup.c,v 1.137 2011/04/11 01:36:59 dholland Exp $");
 
 #include "opt_magiclinks.h"
 
@@ -413,6 +413,8 @@
        int rdonly;                     /* lookup read-only flag bit */
        struct vnode *dp;               /* the directory we are searching */
        int slashes;
+
+       unsigned attempt_retry:1;       /* true if error allows emul retry */
 };
 
 
@@ -1233,35 +1235,15 @@
 //////////////////////////////
 
 static int
-do_namei(struct namei_state *state, struct vnode *forcecwd,
+namei_oneroot(struct namei_state *state, struct vnode *forcecwd,
         int neverfollow, int inhibitmagic)
 {
-       int error;
-
        struct nameidata *ndp = state->ndp;
        struct componentname *cnp = state->cnp;
-       const char *savepath = NULL;
-
-       KASSERT(cnp == &ndp->ni_cnd);
-
-       if (cnp->cn_flags & TRYEMULROOT) {
-               savepath = pathbuf_stringcopy_get(ndp->ni_pathbuf);
-       }
-
-    emul_retry:
-
-       if (savepath != NULL) {
-               /* kinda gross */
-               strcpy(ndp->ni_pathbuf->pb_path, savepath);
-               pathbuf_stringcopy_put(ndp->ni_pathbuf, savepath);
-               savepath = NULL;
-       }
+       int error;
 
        error = namei_start(state, forcecwd);
        if (error) {
-               if (savepath != NULL) {
-                       pathbuf_stringcopy_put(ndp->ni_pathbuf, savepath);
-               }
                return error;
        }
 
@@ -1275,9 +1257,6 @@
                 * XXX: should this also check if it's unlinked?
                 */
                if (state->namei_startdir->v_mount == NULL) {
-                       if (savepath != NULL) {
-                               pathbuf_stringcopy_put(ndp->ni_pathbuf, savepath);
-                       }
                        namei_end(state);
                        return (ENOENT);
                }
@@ -1292,12 +1271,16 @@
                        if (ndp->ni_dvp) {
                                vput(ndp->ni_dvp);
                        }
-                       if (ndp->ni_erootdir != NULL) {
-                               /* Retry the whole thing from the normal root */
-                               cnp->cn_flags &= ~TRYEMULROOT;
-                               goto emul_retry;
-                       }
-                       KASSERT(savepath == NULL);
+                       /*
+                        * Note that if we're doing TRYEMULROOT we can
+                        * retry with the normal root. Setting this
+                        * here matches previous practice, but the
+                        * previous practice didn't make much sense
+                        * and somebody should sit down and figure out
+                        * which cases should cause retry and which
+                        * shouldn't. XXX.
+                        */
+                       state->attempt_retry = 1;
                        return (error);
                }
 
@@ -1316,9 +1299,6 @@
                                vput(ndp->ni_dvp);
                                vput(ndp->ni_vp);
                                ndp->ni_vp = NULL;
-                               if (savepath != NULL) {
-                                       pathbuf_stringcopy_put(ndp->ni_pathbuf, savepath);
-                               }
                                return error;
                        }
                }
@@ -1343,11 +1323,52 @@
                ndp->ni_dvp = NULL;
        }
 
+       return 0;
+}
+
+static int
+namei_tryemulroot(struct namei_state *state, struct vnode *forcecwd,
+        int neverfollow, int inhibitmagic)
+{
+       int error;
+
+       struct nameidata *ndp = state->ndp;
+       struct componentname *cnp = state->cnp;
+       const char *savepath = NULL;
+
+       KASSERT(cnp == &ndp->ni_cnd);
+
+       if (cnp->cn_flags & TRYEMULROOT) {
+               savepath = pathbuf_stringcopy_get(ndp->ni_pathbuf);
+       }
+
+    emul_retry:
+       state->attempt_retry = 0;
+
+       error = namei_oneroot(state, forcecwd, neverfollow, inhibitmagic);
+       if (error) {
+               /*
+                * Once namei has started up, the existence of ni_erootdir
+                * tells us whether we're working from an emulation root.
+                * The TRYEMULROOT flag isn't necessarily authoritative.
+                */
+               if (ndp->ni_erootdir != NULL && state->attempt_retry) {
+                       /* Retry the whole thing using the normal root */
+                       cnp->cn_flags &= ~TRYEMULROOT;
+                       state->attempt_retry = 0;
+
+                       /* kinda gross */
+                       strcpy(ndp->ni_pathbuf->pb_path, savepath);
+                       pathbuf_stringcopy_put(ndp->ni_pathbuf, savepath);
+                       savepath = NULL;
+
+                       goto emul_retry;
+               }
+       }
        if (savepath != NULL) {
                pathbuf_stringcopy_put(ndp->ni_pathbuf, savepath);
        }
-
-       return 0;
+       return error;
 }
 
 int
@@ -1357,7 +1378,8 @@
        int error;
 
        namei_init(&state, ndp);
-       error = do_namei(&state, NULL, 0/*!neverfollow*/, 0/*!inhibitmagic*/);
+       error = namei_tryemulroot(&state, NULL,
+                                 0/*!neverfollow*/, 0/*!inhibitmagic*/);
        namei_cleanup(&state);
 
        return error;
@@ -1386,7 +1408,8 @@
        int error;
 
        namei_init(&state, ndp);
-       error = do_namei(&state, forcecwd, neverfollow, 1/*inhibitmagic*/);
+       error = namei_tryemulroot(&state, forcecwd,
+                                 neverfollow, 1/*inhibitmagic*/);
        namei_cleanup(&state);
 
        return error;