GETPEEREID
Section: Misc. Reference Manual Pages (3bsd)
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BSD mandoc
NAME
getpeereid
- get the effective credentials of a UNIX-domain peer
LIBRARY
Lb libbsd
SYNOPSIS
In sys/types.h
In unistd.h
(See
libbsd(7)
for include usage.)
Ft int
Fn getpeereid int s uid_t *euid gid_t *egid
DESCRIPTION
The
Fn getpeereid
function returns the effective user and group IDs of the
peer connected to a
UNIX
socket.
The argument
Fa s
must be a
UNIX
socket
(
unix(4)
)
of type
SOCK_STREAM
on which either
connect(2)
or
listen(2)
have been called.
The effective used ID is placed in
Fa euid ,
and the effective group ID in
Fa 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
server
to verify the credentials of its client.
Likewise, the client can verify the credentials of the server.
IMPLEMENTATION NOTES
On
Fx ,
Fn getpeereid
is implemented in terms of the
LOCAL_PEERCRED
unix(4)
socket option.
RETURN VALUES
Rv -std getpeereid
ERRORS
The
Fn getpeereid
function
fails if:
- Bq Er EBADF
-
The argument
Fa s
is not a valid descriptor.
- Bq Er ENOTSOCK
-
The argument
Fa s
is a file, not a socket.
- Bq Er ENOTCONN
-
The argument
Fa s
does not refer to a socket on which
connect(2)
or
listen(2)
have been called.
- Bq Er EINVAL
-
The argument
Fa s
does not refer to a socket of type
SOCK_STREAM
or the kernel returned invalid data.
SEE ALSO
connect(2),
getpeername(2),
getsockname(2),
getsockopt(2),
listen(2),
unix(4)
HISTORY
The
Fn getpeereid
function appeared in
Fx 4.6 .