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authorChristoph Hellwig <hch@lst.de>2005-11-08 21:35:04 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2005-11-09 07:55:58 -0800
commite4543eddfd3bf3e0d625841377fa695a519edfd4 (patch)
treeb62546cb0038529bd8cd583333c556ad799f2081 /fs/namei.c
parente4a53cbabc81f04e24a5570b4aa6a6384bdbfc67 (diff)
downloadlinux-e4543eddfd3bf3e0d625841377fa695a519edfd4.tar.bz2
[PATCH] add a vfs_permission helper
Most permission() calls have a struct nameidata * available. This helper takes that as an argument and thus makes sure we pass it down for lookup intents and prepares for per-mount read-only support where we need a struct vfsmount for checking whether a file is writeable. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'fs/namei.c')
-rw-r--r--fs/namei.c23
1 files changed, 19 insertions, 4 deletions
diff --git a/fs/namei.c b/fs/namei.c
index b3f8a1966c9c..25e4ab4ce8b7 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -256,6 +256,21 @@ int permission(struct inode *inode, int mask, struct nameidata *nd)
return security_inode_permission(inode, mask, nd);
}
+/**
+ * vfs_permission - check for access rights to a given path
+ * @nd: lookup result that describes the path
+ * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC)
+ *
+ * Used to check for read/write/execute permissions on a path.
+ * We use "fsuid" for this, letting us set arbitrary permissions
+ * for filesystem access without changing the "normal" uids which
+ * are used for other things.
+ */
+int vfs_permission(struct nameidata *nd, int mask)
+{
+ return permission(nd->dentry->d_inode, mask, nd);
+}
+
/*
* get_write_access() gets write permission for a file.
* put_write_access() releases this write permission.
@@ -765,9 +780,8 @@ static fastcall int __link_path_walk(const char * name, struct nameidata *nd)
nd->flags |= LOOKUP_CONTINUE;
err = exec_permission_lite(inode, nd);
- if (err == -EAGAIN) {
- err = permission(inode, MAY_EXEC, nd);
- }
+ if (err == -EAGAIN)
+ err = vfs_permission(nd, MAY_EXEC);
if (err)
break;
@@ -1407,7 +1421,7 @@ int may_open(struct nameidata *nd, int acc_mode, int flag)
if (S_ISDIR(inode->i_mode) && (flag & FMODE_WRITE))
return -EISDIR;
- error = permission(inode, acc_mode, nd);
+ error = vfs_permission(nd, acc_mode);
if (error)
return error;
@@ -2536,6 +2550,7 @@ EXPORT_SYMBOL(path_lookup);
EXPORT_SYMBOL(path_release);
EXPORT_SYMBOL(path_walk);
EXPORT_SYMBOL(permission);
+EXPORT_SYMBOL(vfs_permission);
EXPORT_SYMBOL(unlock_rename);
EXPORT_SYMBOL(vfs_create);
EXPORT_SYMBOL(vfs_follow_link);