setresuid, setresgid - set real, effective and saved user or group ID
int setresuid(uid_t ruid, uid_t
euid, uid_t suid);
int setresgid(gid_t rgid, gid_t
egid, gid_t sgid);
setresuid (introduced in Linux 2.1.44) sets the real
user ID, the effective user ID, and the saved set-user-ID of
the current process.
Unprivileged user processes (i.e., processes with each of
real, effective and saved user ID nonzero) may change the
real, effective and saved user ID, each to one of: the
current uid, the current effective uid or the current saved
The super-user may set real, effective and saved user ID to
If one of the parameters equals -1, the corresponding value
is not changed.
Completely analogously, setresgid sets the real,
effective and saved group ID's of the current process, with
the same restrictions for processes with each of real,
effective and saved user ID nonzero.
On success, zero is returned. On error, -1 is returned, and
errno is set appropriately.
The current process was not privileged and tried to change
the IDs is a not allowed way.
This call is Linux-specific.
getuid(2), setuid(2), getreuid(2)?,