getpeereid — get
the effective credentials of a UNIX-domain peer
function returns the effective user and group IDs of the peer connected to a
UNIX-domain socket. The argument
s must be a UNIX-domain socket
(unix(4)) of type
SOCK_STREAM on which either
listen(2) have been called. The
effective used ID is placed in euid, and the effective
group ID in egid.
The credentials returned to the listen(2) caller are those of its peer at the time it called connect(2); the credentials returned to the connect(2) caller are those of its peer at the time it called listen(2). This mechanism is reliable; there is no way for either side to influence the credentials returned to its peer except by calling the appropriate system call (i.e., either connect(2) or listen(2)) under different effective credentials.
One common use of this routine is for a UNIX-domain server to verify the credentials of its client. Likewise, the client can verify the credentials of the server.
getpeereid() is implemented in terms of the
unix(4) socket option.
getpeereid() function returns the
value 0 if successful; otherwise the value -1 is returned and
the global variable errno is set to indicate the
getpeereid() function fails if:
- The argument s is not a valid descriptor.
- The argument s is a file, not a socket.
- The argument s does not refer to a socket on which connect(2) or listen(2) have been called.
- The argument s does not refer to a socket of type
SOCK_STREAM, or the kernel returned invalid data.
getpeereid() function appeared in
|July 15, 2001||Linux 6.3.2-arch1-1|