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GETPEEREID(3) | Library Functions Manual | GETPEEREID(3) |
NAME¶
getpeereid
—
LIBRARY¶
library “libbsd”SYNOPSIS¶
#include <sys/types.h>
#include <bsd/unistd.h>
int
getpeereid
(int
s, uid_t *euid,
gid_t *egid);
DESCRIPTION¶
Thegetpeereid
() 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) have been called.
The effective used 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 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-domain server to verify the credentials of its client. Likewise, the client can verify the credentials of the server.
IMPLEMENTATION NOTES¶
On FreeBSD,getpeereid
() is
implemented in terms of the LOCAL_PEERCRED
unix(4) socket option.
RETURN VALUES¶
Thegetpeereid
() 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¶
Thegetpeereid
() 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¶
Thegetpeereid
() function appeared in
FreeBSD 4.6.
July 15, 2001 | Linux 4.9.0-9-amd64 |