linux man page for process-keyring

PROCESS-KEYRING(7)					     Linux Programmer's Manual						PROCESS-KEYRING(7)

NAME
       process-keyring - per-process shared keyring

DESCRIPTION
       The  process  keyring is a keyring used to anchor keys on behalf of a process.  It is created only when a process requests it.  The process
       keyring has the name (description) _pid.

       A special serial number value, KEY_SPEC_PROCESS_KEYRING, is defined that can be used in lieu of the actual serial  number  of  the  calling
       process's process keyring.

       From  the  keyctl(1) utility, '@p' can be used instead of a numeric key ID in much the same way, but since keyctl(1) is a program run after
       forking, this is of no utility.

       A thread created using the clone(2) CLONE_THREAD flag has the same process keyring as the caller of clone(2).  When a new process  is  cre-
       ated  using  fork()  it	initially  has	no  process keyring.  A process's process keyring is cleared on execve(2).  The process keyring is
       destroyed when the last thread that refers to it terminates.

       If a process doesn't have a process keyring when it is accessed, then the process keyring will be created if the keyring is to be modified;
       otherwise, the error ENOKEY results.

SEE ALSO
       keyctl(1), keyctl(3), keyrings(7), persistent-keyring(7), session-keyring(7), thread-keyring(7), user-keyring(7), user-session-keyring(7)

Linux								    2017-03-13							PROCESS-KEYRING(7)