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GETPEEREID(3)	       FreeBSD Library Functions Manual		 GETPEEREID(3)

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)	or listen(2) has been called.  The effective user 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 mech-
     anism is reliable;	there is no way	for either side	to influence the cre-
     dentials 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 creden-
     tials of the server.

IMPLEMENTATION NOTES
     On	FreeBSD, getpeereid() is implemented in	terms of the LOCAL_PEERCRED
     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) or listen(2)	have been called.

     [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 FreeBSD 4.6.

FreeBSD	Ports 11.2	       February	3, 2017		    FreeBSD Ports 11.2

NAME | LIBRARY | SYNOPSIS | DESCRIPTION | IMPLEMENTATION NOTES | RETURN VALUES | ERRORS | SEE ALSO | HISTORY

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