KEYCTL_CLEAR
Clears the list of keys attached to a keyring. Arguments
ecx | Key serial number. It may be one of the following special values:
`KEY_SPEC_THREAD_KEYRING` | `Caller's thread-specific keyring.`
`KEY_SPEC_PROCESS_KEYRING` | `Caller's process-specific keyring.`
`KEY_SPEC_SESSION_KEYRING` | `Caller's session-specific keyring.`
`KEY_SPEC_USER_KEYRING` | `Caller's UID-specific keyring.`
`KEY_SPEC_USER_SESSION_KEYRING` | `Caller's UID-session keyring.`
`KEY_SPEC_GROUP_KEYRING` | `Caller's GID-specific keyring.`
`KEY_SPEC_REQKEY_AUTH_KEY` | `This specifies the authorization key created by request_key() and passed to the process it spawns to generate a key. If a valid keyring ID is passed in, then this will simply be returned if the key exists; an error will be issued if it doesn't exist.`
Return values If the system call succeeds the return value is 0. If the system call fails the return value is one of the following errno values:
`-ENOKEY` | `No matching key was found.`
`-EKEYEXPIRED` | `The keyring specified has expired.`
`-EKEYREVOKED` | `The keyring specified had been revoked.`
`-ENOTDIR` | `ecx is not a valid keyring.`
`-EACCES` | `The keyring exists, but is not writable by the calling process.`
Remarks The calling process must have write permission on the keyring, and it must be a keyring.