Copyright (c) 2001 Dima Dorfman.
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$FreeBSD$

.Dd July 15, 2001 .Dt GETPEEREID 3 .Os .Sh NAME .Nm getpeereid .Nd get the effective credentials of a UNIX-domain peer .Sh LIBRARY .Lb libc .Sh SYNOPSIS n sys/types.h n unistd.h .Ft int .Fn getpeereid "int s" "uid_t *euid" "gid_t *egid" .Sh DESCRIPTION The .Fn getpeereid function returns the effective user and group IDs of the peer connected to a x Ns -domain socket. The argument .Fa s must be a x Ns -domain socket

q Xr unix 4 of type .Dv SOCK_STREAM on which either .Xr connect 2 or .Xr listen 2 have been called. The effective used ID is placed in .Fa euid , and the effective group ID in .Fa egid .

p The credentials returned to the .Xr listen 2 caller are those of its peer at the time it called .Xr connect 2 ; the credentials returned to the .Xr connect 2 caller are those of its peer at the time it called .Xr 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 .Xr connect 2 or .Xr listen 2 ) under different effective credentials.

p One common use of this routine is for a x Ns -domain server to verify the credentials of its client. Likewise, the client can verify the credentials of the server. .Sh IMPLEMENTATION NOTES On .Fx , .Fn getpeereid is implemented in terms of the .Dv LOCAL_PEERCRED .Xr unix 4 socket option. .Sh RETURN VALUES .Rv -std getpeereid .Sh ERRORS The .Fn getpeereid function fails if: l -tag -width Er t Bq Er EBADF The argument .Fa s is not a valid descriptor. t Bq Er ENOTSOCK The argument .Fa s is a file, not a socket. t Bq Er ENOTCONN The argument .Fa s does not refer to a socket on which .Xr connect 2 or .Xr listen 2 have been called. t Bq Er EINVAL The argument .Fa s does not refer to a socket of type .Dv SOCK_STREAM , or the kernel returned invalid data. .El .Sh SEE ALSO .Xr connect 2 , .Xr getpeername 2 , .Xr getsockname 2 , .Xr getsockopt 2 , .Xr listen 2 , .Xr unix 4 .Sh HISTORY The .Fn getpeereid function appeared in .Fx 4.6 .