KEYCTL_GET_PERSISTENT(2const) — Linux manual page

KEYCTL_GET_PERSISTENT(2const)               KEYCTL_GET_PERSISTENT(2const)

NAME         top

       KEYCTL_GET_PERSISTENT - get the persistent keyring for a user

LIBRARY         top

       Standard C library (libc, -lc)

SYNOPSIS         top

       #include <linux/keyctl.h>  /* Definition of KEY* constants */
       #include <sys/syscall.h>   /* Definition of SYS_* constants */
       #include <unistd.h>

       long syscall(SYS_keyctl, KEYCTL_GET_PERSISTENT, uid_t uid,
                    key_serial_t keyring);

DESCRIPTION         top

       Get the persistent keyring (persistent-keyring(7)) for a specified
       user and link it to a specified keyring.

       The user ID is specified in uid.  If the value -1 is specified,
       the caller's real user ID is used.  The ID of the destination
       keyring is specified in keyring.

       The caller must have the CAP_SETUID capability in its user
       namespace in order to fetch the persistent keyring for a user ID
       that does not match either the real or effective user ID of the
       caller.

       If the call is successful, a link to the persistent keyring is
       added to the keyring whose ID was specified in keyring.

       The caller must have write permission on the keyring.

       The persistent keyring will be created by the kernel if it does
       not yet exist.

       Each time the KEYCTL_GET_PERSISTENT operation is performed, the
       persistent keyring will have its expiration timeout reset to the
       value in:

           /proc/sys/kernel/keys/persistent_keyring_expiry

       Should the timeout be reached, the persistent keyring will be
       removed and everything it pins can then be garbage collected.

       Persistent keyrings were added in Linux 3.13.

RETURN VALUE         top

       On success, the ID of the persistent keyring.

       On error, -1 is returned, and errno is set to indicate the error.

ERRORS         top

       EPERM  uid specified a UID other than the calling thread's real or
              effective UID, and the caller did not have the CAP_SETUID
              capability.

VERSIONS         top

       A wrapper is provided in the libkeyutils library:
       keyctl_get_persistent(3).

STANDARDS         top

       Linux.

HISTORY         top

       Linux 3.13.

SEE ALSO         top

       keyctl(2), keyctl_get_persistent(3)

COLOPHON         top

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Linux man-pages 6.15            2025-05-17  KEYCTL_GET_PERSISTENT(2const)

Pages that refer to this page: keyctl(2)

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