man2/add_key.2

   1 .\" Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
   2 .\" Written by David Howells (dhowells@redhat.com)
   3 .\"
   4 .\" This program is free software; you can redistribute it and/or
   5 .\" modify it under the terms of the GNU General Public License
   6 .\" as published by the Free Software Foundation; either version
   7 .\" 2 of the License, or (at your option) any later version.
   8 .\"
   9 .TH ADD_KEY 2 2010-02-25 Linux "Linux Key Management Calls"
  10 .SH NAME
  11 add_key \- add a key to the kernel's key management facility
  12 .SH SYNOPSIS
  13 .nf
  14 .B #include <keyutils.h>
  15 .sp
  16 .BI "key_serial_t add_key(const char *" type ", const char *" description ,
  17 .BI "                     const void *" payload ", size_t " plen ,
  18 .BI "                     key_serial_t " keyring ");"
  19 .fi
  20 .SH DESCRIPTION
  21 .BR add_key ()
  22 asks the kernel to create or update a key of the given
  23 .I type
  24 and
  25 .IR description ,
  26 instantiate it with the
  27 .I payload
  28 of length
  29 .IR plen ,
  30 and to attach it to the nominated
  31 .I keyring
  32 and to return its serial number.
  33 .P
  34 The key type may reject the data if it's in the wrong format or in some other
  35 way invalid.
  36 .P
  37 If the destination
  38 .I keyring
  39 already contains a key that matches the specified
  40 .IR type " and " description
  41 then, if the key type supports it, that key will be updated rather than a new
  42 key being created; if not, a new key will be created and it will displace the
  43 link to the extant key from the keyring.
  44 .P
  45 The destination
  46 .I keyring
  47 serial number may be that of a valid keyring to which the caller has write
  48 permission, or it may be a special keyring ID:
  49 .TP
  50 .B KEY_SPEC_THREAD_KEYRING
  51 This specifies the caller's thread-specific keyring.
  52 .TP
  53 .B KEY_SPEC_PROCESS_KEYRING
  54 This specifies the caller's process-specific keyring.
  55 .TP
  56 .B KEY_SPEC_SESSION_KEYRING
  57 This specifies the caller's session-specific keyring.
  58 .TP
  59 .B KEY_SPEC_USER_KEYRING
  60 This specifies the caller's UID-specific keyring.
  61 .TP
  62 .B KEY_SPEC_USER_SESSION_KEYRING
  63 This specifies the caller's UID-session keyring.
  64 .SH KEY TYPES
  65 There are a number of key types available in the core key management code, and
  66 these can be specified to this function:
  67 .TP
  68 .B \*(lquser\*(rq
  69 Keys of the user-defined key type may contain a blob of arbitrary data, and the
  70 .I description
  71 may be any valid string, though it is preferred that the description be
  72 prefixed with a string representing the service to which the key is of interest
  73 and a colon (for instance
  74 .RB \*(lq afs:mykey \*(rq).
  75 The
  76 .I payload
  77 may be empty or NULL for keys of this type.
  78 .TP
  79 .B \*(lqkeyring\*(rq
  80 Keyrings are special key types that may contain links to sequences of other
  81 keys of any type.
  82 If this interface is used to create a keyring, then a NULL
  83 .I payload
  84 should be specified, and
  85 .I plen
  86 should be zero.
  87 .SH RETURN VALUE
  88 On success
  89 .BR add_key ()
  90 returns the serial number of the key it created or updated.
  91 On error, the value \-1
  92 will be returned and errno will have been set to an appropriate error.
  93 .SH ERRORS
  94 .TP
  95 .B ENOKEY
  96 The keyring doesn't exist.
  97 .TP
  98 .B EKEYEXPIRED
  99 The keyring has expired.
 100 .TP
 101 .B EKEYREVOKED
 102 The keyring has been revoked.
 103 .TP
 104 .B EINVAL
 105 The payload data was invalid.
 106 .TP
 107 .B ENOMEM
 108 Insufficient memory to create a key.
 109 .TP
 110 .B EDQUOT
 111 The key quota for this user would be exceeded by creating this key or linking
 112 it to the keyring.
 113 .TP
 114 .B EACCES
 115 The keyring wasn't available for modification by the user.
 116 .SH LINKING
 117 Although this is a Linux system call, it is not present in
 118 .I libc
 119 but can be found rather in
 120 .IR libkeyutils .
 121 When linking,
 122 .B -lkeyutils
 123 should be specified to the linker.
 124 .SH SEE ALSO
 125 .BR keyctl (1),
 126 .BR keyctl (2),
 127 .BR request_key (2)