keyctl_join_session_keyring man page
keyctl_join_session_keyring — Join a different session keyring
#include <keyutils.h> key_serial_t keyctl_join_session_keyring(const char *name);
keyctl_join_session_keyring() changes the session keyring to which a process is subscribed.
If name is NULL then a new anonymous keyring will be created, and the process will be subscribed to that.
If name points to a string, then if a keyring of that name is available, the process will attempt to subscribe to that keyring, giving an error if that is not permitted; otherwise a new keyring of that name is created and attached as the session keyring.
To attach to an extant named keyring, the keyring must have search permission available to the calling process.
On success keyctl_join_session_keyring() returns the serial number of the key it found or created. On error, the value -1 will be returned and errno will have been set to an appropriate error.
Insufficient memory to create a key.
The key quota for this user would be exceeded by creating this key or linking it to the keyring.
The named keyring exists, but is not searchable by the calling process.
This is a library function that can be found in libkeyutils. When linking, -lkeyutils should be specified to the linker.
keyctl(2), keyctl(3), session-keyring(7).