NAME

       keyctl_get_persistent - get the persistent keyring for a user

SYNOPSIS

       #include <keyutils.h>

       long keyctl_get_persistent(uid_t uid, key_serial_t keyring);

DESCRIPTION

       keyctl_get_persistent() gets the persistent keyring for the specified user ID.  Unlike the
       session and user keyrings, this keyring will persist once all  login  sessions  have  been
       deleted and can thus be used to carry authentication tokens for processes that run without
       user interaction, such as programs started by cron.

       The persistent keyring will be created by the kernel if it does not yet exist.  Each  time
       this  function is called, the persistent keyring will have its expiration timeout reset to
       the value in:

              /proc/sys/kernel/keys/persistent_keyring_expiry

       (by default three days).  Should the timeout be reached, the persistent  keyring  will  be
       removed and everything it pins can then be garbage collected.

       If  uid is -1 then the calling process's real user ID will be used.  If uid is not -1 then
       error EPERM will be given if the user ID requested does not match either the caller's real
       or effective user IDs or if the calling process does not have SetUid capability.

       If successful, a link to the persistent keyring will be added into keyring.

RETURN VALUE

       On  success  keyctl_get_persistent()  returns the serial number of the persistent keyring.
       On error, the value -1 will be returned and errno will have been  set  to  an  appropriate
       error.

ERRORS

       EPERM  Not permitted to access the persistent keyring for the requested uid.

       ENOMEM Insufficient memory to create the persistent keyring or to extend keyring.

       ENOKEY keyring does not exist.

       EKEYEXPIRED
              keyring has expired.

       EKEYREVOKED
              keyring has been revoked.

       EDQUOT The user does not have sufficient quota to extend keyring.

       EACCES keyring exists, but does not grant write permission to the calling process.

LINKING

       This  is  a  library  function that can be found in libkeyutils.  When linking, -lkeyutils
       should be specified to the linker.

SEE ALSO

       keyctl(1), add_key(2), keyctl(2), request_key(2), keyctl(3), keyrings(7), keyutils(7),
       persistent-keyring(7),