getpeereid
- get the effective credentials of a UNIX-domain peer
LIBRARY
Lb libc
SYNOPSIS
#include <sys/types.h>
#include <unistd.h> int
getpeereid (int s uid_t *euid gid_t *egid);
DESCRIPTION
The
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 ,
getpeereid ();
is implemented in terms of the
LOCAL_PEERCREDunix(4)
socket option.
RETURN VALUES
Rv -std getpeereid
ERRORS
The
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.
