[src/trunk]: src/sys/kern Simplify handling of slashes. Provides a proper fix...

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

details:   https://anonhg.NetBSD.org/src/rev/5cc882326685
branches:  trunk
changeset: 768155:5cc882326685
user:      dholland <dholland%NetBSD.org@localhost>
date:      Tue Aug 09 18:37:56 2011 +0000

description:
Simplify handling of slashes. Provides a proper fix for PR 44961.

diffstat:

 sys/kern/vfs_lookup.c |  62 +++++++++++++++++++++-----------------------------
 1 files changed, 26 insertions(+), 36 deletions(-)

diffs (117 lines):

diff -r 662256a8a012 -r 5cc882326685 sys/kern/vfs_lookup.c
--- a/sys/kern/vfs_lookup.c     Tue Aug 09 18:24:46 2011 +0000
+++ b/sys/kern/vfs_lookup.c     Tue Aug 09 18:37:56 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: vfs_lookup.c,v 1.184 2011/05/16 15:09:31 dholland Exp $        */
+/*     $NetBSD: vfs_lookup.c,v 1.185 2011/08/09 18:37:56 dholland Exp $        */
 
 /*
  * Copyright (c) 1982, 1986, 1989, 1993
@@ -37,7 +37,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: vfs_lookup.c,v 1.184 2011/05/16 15:09:31 dholland Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vfs_lookup.c,v 1.185 2011/08/09 18:37:56 dholland Exp $");
 
 #include "opt_magiclinks.h"
 
@@ -1078,7 +1078,6 @@
        struct nameidata *ndp = state->ndp;
        struct componentname *cnp = state->cnp;
        struct vnode *searchdir, *foundobj;
-       const char *cp;
        int error;
 
        error = namei_start(state, forcecwd, &searchdir);
@@ -1087,6 +1086,7 @@
                ndp->ni_vp = NULL;
                return error;
        }
+       KASSERT(searchdir->v_type == VDIR);
 
        /*
         * Setup: break out flag bits into variables.
@@ -1100,11 +1100,28 @@
         * Keep going until we run out of path components.
         */
        cnp->cn_nameptr = ndp->ni_pnbuf;
+
+       /* drop leading slashes (already used them to choose startdir) */
+       while (cnp->cn_nameptr[0] == '/') {
+               cnp->cn_nameptr++;
+               ndp->ni_pathlen--;
+       }
+       /* was it just "/"? */
+       if (cnp->cn_nameptr[0] == '\0') {
+               foundobj = searchdir;
+               searchdir = NULL;
+               cnp->cn_flags |= ISLASTCN;
+
+               /* bleh */
+               goto skiploop;
+       }
+
        for (;;) {
 
                /*
                 * If the directory we're on is unmounted, bail out.
                 * XXX: should this also check if it's unlinked?
+                * XXX: yes it should... but how?
                 */
                if (searchdir->v_mount == NULL) {
                        vput(searchdir);
@@ -1118,40 +1135,11 @@
                 * (currently, this may consume more than one)
                 */
 
-               /*
-                * If we have a leading string of slashes, remove
-                * them, and just make sure the current node is a
-                * directory.
-                */
-               cp = cnp->cn_nameptr;
-               if (*cp == '/') {
-                       do {
-                               cp++;
-                       } while (*cp == '/');
-                       ndp->ni_pathlen -= cp - cnp->cn_nameptr;
-                       cnp->cn_nameptr = cp;
+               /* There should be no slashes here. */
+               KASSERT(cnp->cn_nameptr[0] != '/');
 
-                       if (searchdir->v_type != VDIR) {
-                               vput(searchdir);
-                               ndp->ni_dvp = NULL;
-                               ndp->ni_vp = NULL;
-                               state->attempt_retry = 1;
-                               return ENOTDIR;
-                       }
-               }
-
-               /*
-                * If we've exhausted the path name, then just return the
-                * current node.
-                */
-               if (cnp->cn_nameptr[0] == '\0') {
-                       foundobj = searchdir;
-                       searchdir = NULL;
-                       cnp->cn_flags |= ISLASTCN;
-
-                       /* bleh */
-                       break;
-               }
+               /* and we shouldn't have looped around if we were done */
+               KASSERT(cnp->cn_nameptr[0] != '\0');
 
                error = lookup_parsepath(state);
                if (error) {
@@ -1266,6 +1254,8 @@
                foundobj = NULL;
        }
 
+ skiploop:
+
        if (foundobj != NULL) {
                if (foundobj == ndp->ni_erootdir) {
                        /*