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              keyring has been revoked.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),
       persistent-keyring(7),
       keyutils(7),
       keyrings(7)