1GETPEEREID(3bsd) LOCAL GETPEEREID(3bsd)
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4 getpeereid — get the effective credentials of a UNIX-domain peer
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7 Utility functions from BSD systems (libbsd, -lbsd)
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10 #include <sys/types.h>
11 #include <unistd.h>
12 (See libbsd(7) for include usage.)
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14 int
15 getpeereid(int s, uid_t *euid, gid_t *egid);
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18 The getpeereid() function returns the effective user and group IDs of the
19 peer connected to a UNIX-domain socket. The argument s must be a
20 UNIX-domain socket (unix(4)) of type SOCK_STREAM on which either
21 connect(2) or listen(2) have been called. The effective used ID is
22 placed in euid, and the effective group ID in egid.
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24 The credentials returned to the listen(2) caller are those of its peer at
25 the time it called connect(2); the credentials returned to the connect(2)
26 caller are those of its peer at the time it called listen(2). This mech‐
27 anism is reliable; there is no way for either side to influence the cre‐
28 dentials returned to its peer except by calling the appropriate system
29 call (i.e., either connect(2) or listen(2)) under different effective
30 credentials.
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32 One common use of this routine is for a UNIX-domain server to verify the
33 credentials of its client. Likewise, the client can verify the creden‐
34 tials of the server.
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37 On FreeBSD, getpeereid() is implemented in terms of the LOCAL_PEERCRED
38 unix(4) socket option.
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41 The getpeereid() function returns the value 0 if successful; otherwise
42 the value -1 is returned and the global variable errno is set to indicate
43 the error.
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46 The getpeereid() function fails if:
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48 [EBADF] The argument s is not a valid descriptor.
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50 [ENOTSOCK] The argument s is a file, not a socket.
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52 [ENOTCONN] The argument s does not refer to a socket on which
53 connect(2) or listen(2) have been called.
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55 [EINVAL] The argument s does not refer to a socket of type
56 SOCK_STREAM, or the kernel returned invalid data.
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59 connect(2), getpeername(2), getsockname(2), getsockopt(2), listen(2),
60 unix(4)
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63 The getpeereid() function appeared in FreeBSD 4.6.
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65BSD July 15, 2001 BSD