.\"
.\" Copyright (C) 2006 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 License
.\" as published by the Free Software Foundation; either version
.\" 2 of the License, or (at your option) any later version.
.\"
.TH KEYCTL_SEARCH 3 "4 May 2006" Linux "Linux Key Management Calls"
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.SH NAME
keyctl_search \- Search a keyring for a key
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.SH SYNOPSIS
.nf
.B #include <keyutils.h>
.sp
.BI "long keyctl_search(key_serial_t " keyring ", const char *" type ,
.BI "const char *" description ", key_serial_t " destination ");"
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.SH DESCRIPTION
.BR keyctl_search ()
recursively searches the
.I keyring
for a key of the specified
.I type
and
.IR description .
.P
If found, the key will be attached to the
.I destination
keyring (if given), and its serial number will be returned.
.P
The source keyring must grant
.B search
permission to the caller, and for a key to be found, it must also grant
.B search
permission to the caller.  Child keyrings will be only be recursively searched
if they grant
.B search
permission to the caller as well.
.P
If the destination keyring is
.BR zero ,
no attempt will be made to forge a link to the key, and just the serial number
will be returned.
.P
If the destination keyring is given, then the link may only be formed if the
found key grants the caller
.B link
permission and the destination keyring grants the caller
.B write
permission.
.P
If the search is successful, and if the destination keyring already contains a
link to a key that matches the specified
.IR type " and " description ,
then that link will be replaced by a link to the found key.
.P
The source keyring and destination keyring serial numbers may be those of
valid keyrings to which the caller has appropriate permission, or they may be
special keyring IDs:
.TP
.B KEY_SPEC_THREAD_KEYRING
This specifies the caller's thread-specific keyring.
.TP
.B KEY_SPEC_PROCESS_KEYRING
This specifies the caller's process-specific keyring.
.TP
.B KEY_SPEC_SESSION_KEYRING
This specifies the caller's session-specific keyring.
.TP
.B KEY_SPEC_USER_KEYRING
This specifies the caller's UID-specific keyring.
.TP
.B KEY_SPEC_USER_SESSION_KEYRING
This specifies the caller's UID-session keyring.
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.SH RETURN VALUE
On success
.BR keyctl_search ()
returns the serial number of the key it found.  On error, the value
.B -1
will be returned and errno will have been set to an appropriate error.
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.SH ERRORS
.TP
.B ENOKEY
One of the keyrings doesn't exist, no key was found by the search, or the only
key found by the search was a negative key.
.TP
.B ENOTDIR
One of the keyrings is a valid key that isn't a keyring.
.TP
.B EKEYEXPIRED
One of the keyrings has expired, or the only key found was expired.
.TP
.B EKEYREVOKED
One of the keyrings has been revoked, or the only key found was revoked.
.TP
.B ENOMEM
Insufficient memory to expand the destination keyring.
.TP
.B EDQUOT
The key quota for this user would be exceeded by creating a link to the found
key in the destination keyring.
.TP
.B EACCES
The source keyring didn't grant
.B search
permission, the destination keyring didn't grant
.B write
permission or the found key didn't grant
.B link
permission to the caller.
.\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
.SH LINKING
Although this is a Linux system call, it is not present in
.I libc
but can be found rather in
.IR libkeyutils .
When linking,
.B -lkeyutils
should be specified to the linker.
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.SH SEE ALSO
.BR keyctl (1),
.br
.BR add_key (2),
.br
.BR keyctl (2),
.br
.BR request_key (2),
.br
.BR keyctl (3),
.br
.BR request-key (8)