NAME
getpeereid —
get the effective
credentials of a UNIX-domain peer
LIBRARY
Standard C Library (libc, -lc)
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-domain socket. The
argument
s must be a
UNIX-domain
socket (
unix(4)) of type
SOCK_STREAM
on which either
connect(2) has been called, or
one returned from
accept(2)
after
bind(2) and
listen(2) have been called. If
non-NULL, the effective used ID is placed in
euid, and
the effective group ID in
egid.
The credentials returned to the
accept(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
bind(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
bind(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.
IMPLEMENTATION NOTES
On
NetBSD,
getpeereid() is implemented
in terms of the
LOCAL_PEEREID
unix(4) socket option.
RETURN VALUES
The
getpeereid() function returns the value 0 if
successful; otherwise the value -1 is returned and the global variable
errno is set to indicate the error.
ERRORS
The
getpeereid() function fails if:
-
-
- [
EBADF
]
- The argument s is not a valid
descriptor.
-
-
- [
ENOTSOCK
]
- The argument s is a file, not a
socket.
-
-
- [
ENOTCONN
]
- The argument s does not refer to a
socket on which connect(2)
have been called nor one returned from
listen(2).
-
-
- [
EINVAL
]
- The argument 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
getpeereid() function appeared in
NetBSD
5.0.