KEYCTL\_UPDATE(3) Linux Key Management Calls KEYCTL\_UPDATE(3) # [NAME](#NAME) keyctl\_update - update a key # [SYNOPSIS](#SYNOPSIS) ``` #include long keyctl_update(key_serial_t key, const void *payload, size_t plen); ``` # [DESCRIPTION](#DESCRIPTION) **keyctl\_update**() updates the payload of a key if the key type permits it. The caller must have **write** permission on a key to be able to update it. *payload* and *plen* specify the data for the new payload. *payload* may be NULL and *plen* may be zero if the key type permits that. The key type may reject the data if it's in the wrong format or in some other way invalid. # [RETURN VALUE](#RETURN_VALUE) On success **keyctl\_update**() returns **0**. On error, the value **-1** will be returned and *errno* will have been set to an appropriate error. # [ERRORS](#ERRORS) [**ENOKEY**](#ENOKEY) The key specified is invalid. [**EKEYEXPIRED**](#EKEYEXPIRED) The key specified has expired. [**EKEYREVOKED**](#EKEYREVOKED) The key specified had been revoked. [**EINVAL**](#EINVAL) The payload data was invalid. [**ENOMEM**](#ENOMEM) Insufficient memory to store the new payload. [**EDQUOT**](#EDQUOT) The key quota for this user would be exceeded by increasing the size of the key to accommodate the new payload. [**EACCES**](#EACCES) The key exists, but is not **writable** by the calling process. [**EOPNOTSUPP**](#EOPNOTSUPP) The key type does not support the update operation on its keys. # [LINKING](#LINKING) This is a library function that can be found in *libkeyutils*. When linking, **-lkeyutils** should be specified to the linker. # [SEE ALSO](#SEE_ALSO) [**keyctl**(1)](/man/os/keyutils/keyctl.1), [**add\_key**(2)](/man/os/keyutils/add_key.2), [**keyctl**(2)](/man/os/keyutils/keyctl.2), [**request\_key**(2)](/man/os/keyutils/request_key.2), [**keyctl**(3)](/man/os/keyutils/keyctl.3), [**keyrings**(7)](/man/os/keyutils/keyrings.7), [**keyutils**(7)](/man/os/keyutils/keyutils.7) 4 May 2006 Linux --- Document: keyctl_update(3) from keyutils 1.6.3-r41 (Chainguard OS) Source: https://kernel.googlesource.com/pub/scm/linux/kernel/git/dhowells/keyutils.git