[src/trunk]: src/sys/fs/tmpfs tmpfs: fix the zero-length symlink target case ...

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

details:   https://anonhg.NetBSD.org/src/rev/916b5c87c152
branches:  trunk
changeset: 791040:916b5c87c152
user:      rmind <rmind%NetBSD.org@localhost>
date:      Fri Nov 01 15:38:45 2013 +0000

description:
tmpfs: fix the zero-length symlink target case as NetBSD supports them.

diffstat:

 sys/fs/tmpfs/tmpfs_subr.c  |  15 ++++++++++-----
 sys/fs/tmpfs/tmpfs_vnops.c |  15 +++++++++------
 2 files changed, 19 insertions(+), 11 deletions(-)

diffs (75 lines):

diff -r 469c2c7712d0 -r 916b5c87c152 sys/fs/tmpfs/tmpfs_subr.c
--- a/sys/fs/tmpfs/tmpfs_subr.c Fri Nov 01 15:33:48 2013 +0000
+++ b/sys/fs/tmpfs/tmpfs_subr.c Fri Nov 01 15:38:45 2013 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: tmpfs_subr.c,v 1.81 2013/10/31 00:59:17 rmind Exp $    */
+/*     $NetBSD: tmpfs_subr.c,v 1.82 2013/11/01 15:38:45 rmind Exp $    */
 
 /*
  * Copyright (c) 2005-2011 The NetBSD Foundation, Inc.
@@ -74,7 +74,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: tmpfs_subr.c,v 1.81 2013/10/31 00:59:17 rmind Exp $");
+__KERNEL_RCSID(0, "$NetBSD: tmpfs_subr.c,v 1.82 2013/11/01 15:38:45 rmind Exp $");
 
 #include <sys/param.h>
 #include <sys/dirent.h>
@@ -167,11 +167,16 @@
        case VLNK:
                /* Symbolic link.  Target specifies the file name. */
                KASSERT(target != NULL);
+               nnode->tn_size = strlen(target);
 
-               nnode->tn_size = strlen(target);
-               KASSERT(nnode->tn_size > 0);
+               if (nnode->tn_size == 0) {
+                       /* Zero-length targets are supported. */
+                       nnode->tn_spec.tn_lnk.tn_link = NULL;
+                       break;
+               }
+
                KASSERT(nnode->tn_size < MAXPATHLEN);
-               nnode->tn_size++; /* include the NIL */
+               nnode->tn_size++; /* include the NUL terminator */
 
                nnode->tn_spec.tn_lnk.tn_link =
                    tmpfs_strname_alloc(tmp, nnode->tn_size);
diff -r 469c2c7712d0 -r 916b5c87c152 sys/fs/tmpfs/tmpfs_vnops.c
--- a/sys/fs/tmpfs/tmpfs_vnops.c        Fri Nov 01 15:33:48 2013 +0000
+++ b/sys/fs/tmpfs/tmpfs_vnops.c        Fri Nov 01 15:38:45 2013 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: tmpfs_vnops.c,v 1.104 2013/10/31 00:59:17 rmind Exp $  */
+/*     $NetBSD: tmpfs_vnops.c,v 1.105 2013/11/01 15:38:45 rmind Exp $  */
 
 /*
  * Copyright (c) 2005, 2006, 2007 The NetBSD Foundation, Inc.
@@ -35,7 +35,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: tmpfs_vnops.c,v 1.104 2013/10/31 00:59:17 rmind Exp $");
+__KERNEL_RCSID(0, "$NetBSD: tmpfs_vnops.c,v 1.105 2013/11/01 15:38:45 rmind Exp $");
 
 #include <sys/param.h>
 #include <sys/dirent.h>
@@ -1036,11 +1036,14 @@
        KASSERT(VOP_ISLOCKED(vp));
        KASSERT(uio->uio_offset == 0);
        KASSERT(vp->v_type == VLNK);
-       KASSERT(node->tn_size > 0);
 
-       /* Note: readlink(2) returns the path without NIL. */
-       error = uiomove(node->tn_spec.tn_lnk.tn_link,
-           MIN(node->tn_size - 1, uio->uio_resid), uio);
+       /* Note: readlink(2) returns the path without NUL terminator. */
+       if (node->tn_size > 0) {
+               error = uiomove(node->tn_spec.tn_lnk.tn_link,
+                   MIN(node->tn_size - 1, uio->uio_resid), uio);
+       } else {
+               error = 0;
+       }
        node->tn_status |= TMPFS_NODE_ACCESSED;
 
        return error;