man2/add_key.2

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  10 .\"
  11 .TH ADD_KEY 2 2016-07-17 Linux "Linux Key Management Calls"
  12 .SH NAME
  13 add_key \- add a key to the kernel's key management facility
  14 .SH SYNOPSIS
  15 .nf
  16 .B #include <keyutils.h>
  17 .sp
  18 .BI "key_serial_t add_key(const char *" type ", const char *" description ,
  19 .BI "                     const void *" payload ", size_t " plen ,
  20 .BI "                     key_serial_t " keyring ");"
  21 .fi
  22 .SH DESCRIPTION
  23 .BR add_key ()
  24 asks the kernel to create or update a key of the given
  25 .I type
  26 and
  27 .IR description ,
  28 instantiate it with the
  29 .I payload
  30 of length
  31 .IR plen ,
  32 and to attach it to the nominated
  33 .I keyring
  34 and to return its serial number.
  35 .P
  36 The key type may reject the data if it's in the wrong format or in some other
  37 way invalid.
  38 .P
  39 If the destination
  40 .I keyring
  41 already contains a key that matches the specified
  42 .IR type " and " description,
  43 then, if the key type supports it, that key will be updated rather than a new
  44 key being created; if not, a new key will be created and it will displace the
  45 link to the extant key from the keyring.
  46 .P
  47 The destination
  48 .I keyring
  49 serial number may be that of a valid keyring to which the caller has write
  50 permission, or it may be a special keyring ID:
  51 .TP
  52 .B KEY_SPEC_THREAD_KEYRING
  53 This specifies the caller's thread-specific keyring.
  54 .TP
  55 .B KEY_SPEC_PROCESS_KEYRING
  56 This specifies the caller's process-specific keyring.
  57 .TP
  58 .B KEY_SPEC_SESSION_KEYRING
  59 This specifies the caller's session-specific keyring.
  60 .TP
  61 .B KEY_SPEC_USER_KEYRING
  62 This specifies the caller's UID-specific keyring.
  63 .TP
  64 .B KEY_SPEC_USER_SESSION_KEYRING
  65 This specifies the caller's UID-session keyring.
  66 .SH KEY TYPES
  67 There are a number of key types available in the core key management code, and
  68 these can be specified to this function:
  69 .TP
  70 .B \*(lquser\*(rq
  71 Keys of the user-defined key type may contain a blob of arbitrary data, and the
  72 .I description
  73 may be any valid string, though it is preferred that the description be
  74 prefixed with a string representing the service to which the key is of interest
  75 and a colon (for instance
  76 .RB \*(lq afs:mykey \*(rq).
  77 .TP
  78 .B \*(lqkeyring\*(rq
  79 Keyrings are special key types that may contain links to sequences of other
  80 keys of any type.
  81 If this interface is used to create a keyring, then a NULL
  82 .I payload
  83 should be specified, and
  84 .I plen
  85 should be zero.
  86 .SH RETURN VALUE
  87 On success
  88 .BR add_key ()
  89 returns the serial number of the key it created or updated.
  90 On error, the value \-1
  91 will be returned and errno will have been set to an appropriate error.
  92 .SH ERRORS
  93 .TP
  94 .B EACCES
  95 The keyring wasn't available for modification by the user.
  96 .TP
  97 .B EINVAL
  98 The payload data was invalid.
  99 .TP
 100 .B EKEYEXPIRED
 101 The keyring has expired.
 102 .TP
 103 .B EKEYREVOKED
 104 The keyring has been revoked.
 105 .TP
 106 .B ENOKEY
 107 The keyring doesn't exist.
 108 .TP
 109 .B ENOMEM
 110 Insufficient memory to create a key.
 111 .TP
 112 .B EDQUOT
 113 The key quota for this user would be exceeded by creating this key or linking
 114 it to the keyring.
 115 .SH LINKING
 116 Although this is a Linux system call, it is not present in
 117 .I libc
 118 but can be found rather in
 119 .IR libkeyutils .
 120 When linking,
 121 .B -lkeyutils
 122 should be specified to the linker.
 123 .SH SEE ALSO
 124 .BR keyctl (1),
 125 .BR keyctl (2),
 126 .BR request_key (2),
 127 .BR keyctl (3),
 128 .BR keyrings (7)