KEYCTL_LINK(2const) - Linux manual page (original) (raw)

KEYCTLLINK(2const) KEYCTLLINK(2const)

NAME top

   KEYCTL_LINK - link a key to a keyring

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_LINK, key_serial_t** _key_**,**
                **key_serial_t** _keyring_**);**

DESCRIPTION top

   Create a link from a keyring to a key.

   The key to be linked is specified in _key_; the keyring is specified
   in _keyring_.

   If a key with the same type and description is already linked in
   the keyring, then that key is displaced from the keyring.

   Before creating the link, the kernel checks the nesting of the
   keyrings and returns appropriate errors if the link would produce
   a cycle or if the nesting of keyrings would be too deep (The limit
   on the nesting of keyrings is determined by the kernel constant
   **KEYRING_SEARCH_MAX_DEPTH**, defined with the value 6, and is
   necessary to prevent overflows on the kernel stack when
   recursively searching keyrings).

   The caller must have _link_ permission on the key being added and
   _write_ permission on the keyring.

RETURN VALUE top

   On success, 0 is returned.

   On error, -1 is returned, and _[errno](../man3/errno.3.html)_ is set to indicate the error.

ERRORS top

   **EDEADLK**
          The requested link would result in a cycle.

   **ELOOP** The requested link would cause the maximum nesting depth
          for keyrings to be exceeded.

   **ENFILE** (before Linux 3.13)
          The keyring is full.  (Before Linux 3.13, the available
          space for storing keyring links was limited to a single
          page of memory; since Linux 3.13, there is no fixed limit.)

VERSIONS top

   A wrapper is provided in the _libkeyutils_ library: [keyctl_link(3)](../man3/keyctl%5Flink.3.html).

STANDARDS top

   Linux.

HISTORY top

   Linux 2.6.10.

SEE ALSO top

   [keyctl(2)](../man2/keyctl.2.html), [keyctl_link(3)](../man3/keyctl%5Flink.3.html), [KEYCTL_UNLINK(2const)](../man2/KEYCTL%5FUNLINK.2const.html)

COLOPHON top

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Linux man-pages 6.10 2024-08-21 KEYCTLLINK(2const)

Pages that refer to this page:keyctl(2), KEYCTL_INSTANTIATE(2const), KEYCTL_SEARCH(2const), KEYCTL_SETPERM(2const), KEYCTL_UNLINK(2const)