man7/process-keyring.7

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  12 .TH "PROCESS-KEYRING" 7 2017-03-13 Linux "Linux Programmer's Manual"
  13 .SH NAME
  14 process-keyring \- per-process shared keyring
  15 .SH DESCRIPTION
  16 The process keyring is a keyring used to anchor keys on behalf of a process.
  17 It is created only when a process requests it.
  18 The process keyring has the name (description)
  19 .IR _pid .
  20 .PP
  21 A special serial number value,
  22 .BR KEY_SPEC_PROCESS_KEYRING ,
  23 is defined that can be used in lieu of the actual serial number of
  24 the calling process's process keyring.
  25 .PP
  26 From the
  27 .BR keyctl (1)
  28 utility, '\fB@p\fP' can be used instead of a numeric key ID in
  29 much the same way, but since
  30 .BR keyctl (1)
  31 is a program run after forking, this is of no utility.
  32 .PP
  33 A thread created using the
  34 .BR clone (2)
  35 .B CLONE_THREAD
  36 flag has the same process keyring as the caller of
  37 .BR clone (2).
  38 When a new process is created using
  39 .BR fork ()
  40 it initially has no process keyring.
  41 A process's process keyring is cleared on
  42 .BR execve (2).
  43 The process keyring is destroyed when the last
  44 thread that refers to it terminates.
  45 .PP
  46 If a process doesn't have a process keyring when it is accessed,
  47 then the process keyring will be created if the keyring is to be modified;
  48 otherwise, the error
  49 .B ENOKEY
  50 results.
  51 .SH SEE ALSO
  52 .ad l
  53 .nh
  54 .BR keyctl (1),
  55 .BR keyctl (3),
  56 .BR keyrings (7),
  57 .BR persistent\-keyring (7),
  58 .BR session\-keyring (7),
  59 .BR thread\-keyring (7),
  60 .BR user\-keyring (7),
  61 .BR user\-session\-keyring (7)