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depends on the |
.b lc_ctype |
category of the |
current locale. |
.pp |
passing null as |
.i ps |
is not multithread safe. |
.sh see also |
.br iconv (3), |
.br mbrtowc (3), |
.br mbsinit (3), |
.br mbsnrtowcs (3), |
.br mbstowcs (3) |
.sh colophon |
this page is part of release 5.13 of the linux |
.i man-pages |
project. |
a description of the project, |
information about reporting bugs, |
and the latest version of this page, |
can be found at |
\%https://www.kernel.org/doc/man\-pages/. |
.\" copyright (c) 2006 red hat, inc. all rights reserved. |
.\" written by david howells (dhowells@redhat.com) |
.\" and copyright (c) 2016 michael kerrisk <mtk.man-pages@gmail.com> |
.\" |
.\" %%%license_start(gplv2+_sw_onepara) |
.\" 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. |
.\" %%%license_end |
.\" |
.th request_key 2 2021-08-27 linux "linux key management calls" |
.sh name |
request_key \- request a key from the kernel's key management facility |
.sh synopsis |
.nf |
.b #include <keyutils.h> |
.pp |
.bi "key_serial_t request_key(const char *" type ", const char *" description , |
.bi " const char *" callout_info , |
.bi " key_serial_t " dest_keyring ");" |
.fi |
.pp |
.ir note : |
there is no glibc wrapper for this system call; see notes. |
.sh description |
.br request_key () |
attempts to find a key of the given |
.i type |
with a description (name) that matches the specified |
.ir description . |
if such a key could not be found, then the key is optionally created. |
if the key is found or created, |
.br request_key () |
attaches it to the keyring whose id is specified in |
.i dest_keyring |
and returns the key's serial number. |
.pp |
.br request_key () |
first recursively searches for a matching key in all of the keyrings |
attached to the calling process. |
the keyrings are searched in the order: thread-specific keyring, |
process-specific keyring, and then session keyring. |
.pp |
if |
.br request_key () |
is called from a program invoked by |
.br request_key () |
on behalf of some other process to generate a key, then the keyrings of that |
other process will be searched next, |
using that other process's user id, group id, |
supplementary group ids, and security context to determine access. |
.\" david howells: we can then have an arbitrarily long sequence |
.\" of "recursive" request-key upcalls. there is no limit, other |
.\" than number of pids, etc. |
.pp |
the search of the keyring tree is breadth-first: |
the keys in each keyring searched are checked for a match before any child |
keyrings are recursed into. |
only keys for which the caller has |
.i search |
permission be found, and only keyrings for which the caller has |
.i search |
permission may be searched. |
.pp |
if the key is not found and |
.i callout |
is null, then the call fails with the error |
.br enokey . |
.pp |
if the key is not found and |
.i callout |
is not null, then the kernel attempts to invoke a user-space |
program to instantiate the key. |
the details are given below. |
.pp |
Subsets and Splits