add_key(2) - phpMan
ADD_KEY(2) Linux Key Management Calls ADD_KEY(2)
add_key - add a key to the kernel's key management facility
key_serial_t add_key(const char *type, const char *description,
const void *payload, size_t plen,
add_key() asks the kernel to create or update a key of the given type and description,
instantiate it with the payload of length plen, and to attach it to the nominated keyring
and to return its serial number.
The key type may reject the data if it's in the wrong format or in some other way invalid.
If the destination keyring already contains a key that matches the specified type and
description, then, if the key type supports it, that key will be updated rather than a new
key being created; if not, a new key will be created and it will displace the link to the
extant key from the keyring.
The destination keyring serial number may be that of a valid keyring to which the caller
has write permission, or it may be a special keyring ID:
This specifies the caller's thread-specific keyring.
This specifies the caller's process-specific keyring.
This specifies the caller's session-specific keyring.
This specifies the caller's UID-specific keyring.
This specifies the caller's UID-session keyring.
There are a number of key types available in the core key management code, and these can
be specified to this function:
“user” Keys of the user-defined key type may contain a blob of arbitrary data, and the
description may be any valid string, though it is preferred that the description be
prefixed with a string representing the service to which the key is of interest and
a colon (for instance “afs:mykey”). The payload may be empty or NULL for keys of
Keyrings are special key types that may contain links to sequences of other keys of
any type. If this interface is used to create a keyring, then a NULL payload
should be specified, and plen should be zero.
On success add_key() returns the serial number of the key it created or updated. On
error, the value -1 will be returned and errno will have been set to an appropriate error.
ENOKEY The keyring doesn't exist.
The keyring has expired.
The keyring has been revoked.
EINVAL The payload data was invalid.
ENOMEM Insufficient memory to create a key.
EDQUOT The key quota for this user would be exceeded by creating this key or linking it to
EACCES The keyring wasn't available for modification by the user.
Although this is a Linux system call, it is not present in libc but can be found rather in
libkeyutils. When linking, -lkeyutils should be specified to the linker.
keyctl(1), keyctl(2), request_key(2)
This page is part of release 3.74 of the Linux man-pages project. A description of the
project, information about reporting bugs, and the latest version of this page, can be
found at http://www.kernel.org/doc/man-pages/.
Linux 2010-02-25 ADD_KEY(2)