[src/trunk]: src/sys/kern Tidy up namei internals to allow openat() and frien...

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

details:   https://anonhg.NetBSD.org/src/rev/402c3848b79f
branches:  trunk
changeset: 781946:402c3848b79f
user:      dholland <dholland%NetBSD.org@localhost>
date:      Mon Oct 08 23:41:39 2012 +0000

description:
Tidy up namei internals to allow openat() and friends without getting
tangled in nfsd's special cases.

diffstat:

 sys/kern/vfs_lookup.c |  33 ++++++++++++++++++++-------------
 1 files changed, 20 insertions(+), 13 deletions(-)

diffs (126 lines):

diff -r 1a39c5644bc0 -r 402c3848b79f sys/kern/vfs_lookup.c
--- a/sys/kern/vfs_lookup.c     Mon Oct 08 22:39:15 2012 +0000
+++ b/sys/kern/vfs_lookup.c     Mon Oct 08 23:41:39 2012 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: vfs_lookup.c,v 1.192 2011/09/27 02:10:55 christos Exp $        */
+/*     $NetBSD: vfs_lookup.c,v 1.193 2012/10/08 23:41:39 dholland Exp $        */
 
 /*
  * Copyright (c) 1982, 1986, 1989, 1993
@@ -37,7 +37,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: vfs_lookup.c,v 1.192 2011/09/27 02:10:55 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vfs_lookup.c,v 1.193 2012/10/08 23:41:39 dholland Exp $");
 
 #include "opt_magiclinks.h"
 
@@ -511,7 +511,7 @@
  * to the starting dir.
  */
 static struct vnode *
-namei_getstartdir(struct namei_state *state)
+namei_getstartdir(struct namei_state *state, struct vnode *forcecwd)
 {
        struct nameidata *ndp = state->ndp;
        struct componentname *cnp = state->cnp;
@@ -545,7 +545,11 @@
        }
 
        /* current dir */
-       curdir = cwdi->cwdi_cdir;
+       if (forcecwd != NULL) {
+               curdir = forcecwd;
+       } else {
+               curdir = cwdi->cwdi_cdir;
+       }
 
        if (ndp->ni_pnbuf[0] != '/') {
                startdir = curdir;
@@ -581,6 +585,8 @@
 static struct vnode *
 namei_getstartdir_for_nfsd(struct namei_state *state, struct vnode *startdir)
 {
+       KASSERT(startdir != NULL);
+
        /* always use the real root, and never set an emulation root */
        state->ndp->ni_rootdir = rootvnode;
        state->ndp->ni_erootdir = NULL;
@@ -628,7 +634,7 @@
  * appropriate.
  */
 static int
-namei_start(struct namei_state *state, struct vnode *forcecwd,
+namei_start(struct namei_state *state, struct vnode *forcecwd, int isnfsd,
            struct vnode **startdir_ret)
 {
        struct nameidata *ndp = state->ndp;
@@ -647,11 +653,11 @@
        ndp->ni_loopcnt = 0;
 
        /* Get starting directory, set up root, and ktrace. */
-       if (forcecwd != NULL) {
+       if (isnfsd) {
                startdir = namei_getstartdir_for_nfsd(state, forcecwd);
                /* no ktrace */
        } else {
-               startdir = namei_getstartdir(state);
+               startdir = namei_getstartdir(state, forcecwd);
                namei_ktrace(state);
        }
 
@@ -1098,14 +1104,14 @@
  */
 static int
 namei_oneroot(struct namei_state *state, struct vnode *forcecwd,
-        int neverfollow, int inhibitmagic)
+        int neverfollow, int inhibitmagic, int isnfsd)
 {
        struct nameidata *ndp = state->ndp;
        struct componentname *cnp = state->cnp;
        struct vnode *searchdir, *foundobj;
        int error;
 
-       error = namei_start(state, forcecwd, &searchdir);
+       error = namei_start(state, forcecwd, isnfsd, &searchdir);
        if (error) {
                ndp->ni_dvp = NULL;
                ndp->ni_vp = NULL;
@@ -1412,7 +1418,7 @@
  */
 static int
 namei_tryemulroot(struct namei_state *state, struct vnode *forcecwd,
-        int neverfollow, int inhibitmagic)
+        int neverfollow, int inhibitmagic, int isnfsd)
 {
        int error;
 
@@ -1429,7 +1435,7 @@
     emul_retry:
        state->attempt_retry = 0;
 
-       error = namei_oneroot(state, forcecwd, neverfollow, inhibitmagic);
+       error = namei_oneroot(state, forcecwd, neverfollow, inhibitmagic, isnfsd);
        if (error) {
                /*
                 * Once namei has started up, the existence of ni_erootdir
@@ -1466,7 +1472,8 @@
 
        namei_init(&state, ndp);
        error = namei_tryemulroot(&state, NULL,
-                                 0/*!neverfollow*/, 0/*!inhibitmagic*/);
+                                 0/*!neverfollow*/, 0/*!inhibitmagic*/,
+                                 0/*isnfsd*/);
        namei_cleanup(&state);
 
        if (error) {
@@ -1499,7 +1506,7 @@
 
        namei_init(&state, ndp);
        error = namei_tryemulroot(&state, forcecwd,
-                                 neverfollow, 1/*inhibitmagic*/);
+                                 neverfollow, 1/*inhibitmagic*/, 1/*isnfsd*/);
        namei_cleanup(&state);
 
        if (error) {