process-keyring.7: New page adopted from keyutils

Since this page documents kernel-user-space interfaces,
it makes sense to have it as part of man-pages, rather
than the keyutils package.

Signed-off-by: David Howells <dhowells@redhat.com>

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

man7/process-keyring.7

@@ -0,0 +1,53 @@
+.\"
+.\" Copyright (C) 2014 Red Hat, Inc. All Rights Reserved.
+.\" Written by David Howells (dhowells@redhat.com)
+.\"
+.\" This program is free software; you can redistribute it and/or
+.\" modify it under the terms of the GNU General Public Licence
+.\" as published by the Free Software Foundation; either version
+.\" 2 of the Licence, or (at your option) any later version.
+.\"
+.TH "PROCESS KEYRING" 7 "19 Feb 2014" Linux "Kernel key management"
+.\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
+.SH NAME
+process_keyring \- Per-process shared keyring
+.SH DESCRIPTION
+The
+.B process keyring
+is a keyring used to anchor keys on behalf of a process.  It is only created
+when a process requests it.
+.P
+A special serial number value, \fBKEY_SPEC_PROCESS_KEYRING\fP, is defined that
+can be used in lieu of the calling process's process keyring's actual serial
+number.
+.P
+From the keyctl utility, '\fB@p\fP' can be used instead of a numeric key ID in
+much the same way, but as keyctl is a program run after forking, this is of no
+utility.
+.P
+A process's process keyring is inherited across clone() with CLONE_THREAD and
+is cleared by execve().  The process keyring will be destroyed when the last
+thread that refers to it exits.
+.P
+If a process doesn't have a process keyring when it is accessed, then the
+process keyring will be created if the keyring is to be modified, otherwise
+error ENOKEY will be issued.
+.\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
+.SH SEE ALSO
+.BR keyctl (1),
+.br
+.BR keyctl (3),
+.br
+.BR keyrings (7),
+.br
+.BR thread-keyring (7),
+.br
+.BR process-keyring (7),
+.br
+.BR session-keyring (7),
+.br
+.BR user-keyring (7),
+.br
+.BR user-session-keyring (7),
+.br
+.BR persistent-keyring (7)