KEYCTL_GET_PERSISTENT(3) Linux Key Management Calls KEYCTL_GET_PERSISTENT(3)
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 per-
sist once all login sessions have been deleted and can thus be used to
carry authentication tokens for processes that run without user inter-
action, 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 col-
lected.
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 ex-
tend 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keyring has been revoked.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 call-
ing 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),
Linux 20 Feb 2014 KEYCTL_GET_PERSISTENT(3)
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