Problem - Kevin Tafuro

msg.msg_iov->iov_base = (void *)&sync;
msg.msg_iov->iov_len = sizeof(sync);
return (sendmsg(sd, &msg, 0) != -1);
}
On all platforms, it is possible to obtain credentials from a peer at any point during
the connection; however, it often makes the most sense to get the information immediately
after the connection is established. For example, if your server needs to get
the credentials of each client that connects, the server code might look something
like this:
typedef void (*spc_client_fn)(spc_socket_t *, spc_credentials *, void *);
void spc_unix_server(spc_client_fn callback, void *arg) {
spc_socket_t *client, *listener;
spc_credentials *credentials;
listener = spc_socket_listen(SOCK_STREAM, 0, "127.0.0.1", 2222);
while ((client = spc_socket_accept(listener)) != 0) {
if (!(credentials = spc_get_credentials(client->sd))) {
printf("Unable to get credentials from connecting client!\n");
spc_socket_close(client);
} else {
printf("Client credentials:\n\tuid: %d\n\tgid: %d\n",
SPC_PEER_UID(credentials), SPC_PEER_GID(credentials));
/* do something with the credentials and the connection ... */
callback(client, credentials, arg);
}
}
}
The corresponding client code might look something like this:
spc_socket_t *spc_unix_connect(void) {
spc_socket_t *conn;
if (!(conn = spc_socket_connect("127.0.0.1", 2222))) {
printf("Unable to connect to the server!\n");
return 0;
}
if (!spc_send_credentials(conn->sd)) {
printf("Unable to send credentials to the server!\n");
spc_socket_close(conn);
return 0;
}
printf("Credentials were successfully sent to the server.\n");
return conn;
}
Note finally that while it is possible to obtain credentials from a peer at any point
during the connection, many implementations will send the credentials only once. If
you need the credential information at more than one point during a conversation,
you should make sure to save the information that was obtained the first time it was
needed.
Performing Authentication with Unix Domain Sockets | 485
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