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authorDavid Howells <dhowells@redhat.com>2008-11-14 10:39:26 +1100
committerJames Morris <jmorris@namei.org>2008-11-14 10:39:26 +1100
commit98870ab0a5a3f1822aee681d2997017e1c87d026 (patch)
tree4f28b9732777b114d5ef2f1647289a48e00a6fda /include
parentd76b0d9b2d87cfc95686e148767cbf7d0e22bdc0 (diff)
CRED: Documentation
Document credentials and the new credentials API. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/cred.h12
1 files changed, 11 insertions, 1 deletions
diff --git a/include/linux/cred.h b/include/linux/cred.h
index 8edb4d1d542..794aab5c66e 100644
--- a/include/linux/cred.h
+++ b/include/linux/cred.h
@@ -1,4 +1,4 @@
-/* Credentials management
+/* Credentials management - see Documentation/credentials.txt
*
* Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
@@ -169,6 +169,12 @@ static inline struct cred *get_new_cred(struct cred *cred)
*
* Get a reference on the specified set of credentials. The caller must
* release the reference.
+ *
+ * This is used to deal with a committed set of credentials. Although the
+ * pointer is const, this will temporarily discard the const and increment the
+ * usage count. The purpose of this is to attempt to catch at compile time the
+ * accidental alteration of a set of credentials that should be considered
+ * immutable.
*/
static inline const struct cred *get_cred(const struct cred *cred)
{
@@ -181,6 +187,10 @@ static inline const struct cred *get_cred(const struct cred *cred)
*
* Release a reference to a set of credentials, deleting them when the last ref
* is released.
+ *
+ * This takes a const pointer to a set of credentials because the credentials
+ * on task_struct are attached by const pointers to prevent accidental
+ * alteration of otherwise immutable credential sets.
*/
static inline void put_cred(const struct cred *_cred)
{