#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <stdio.h>
#include <err.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>

#define NAME "/tmp/socket"
#define SZ 106

int main(int argc, char **argv)
{
    int sock, msgsock;
    ssize_t rval;
    int one = 1;
    struct sockaddr_un server, client;
    char buf[1024];

    sock = socket(AF_UNIX, SOCK_STREAM, 0);
    if (sock == -1)
        err(EXIT_FAILURE, "opening stream socket");

    memset(&server, 0, sizeof(server));
    server.sun_family = AF_UNIX;
    strlcpy(server.sun_path, NAME, sizeof(server.sun_path));
    server.sun_len = SUN_LEN(&server);

    (void)setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));

    (void) unlink(NAME);
    if (bind(sock, (struct sockaddr *) &server, server.sun_len)) {
        perror("binding stream socket");
        exit(1);
    }

    printf("server: Socket has name %s\n", server.sun_path);
    printf("server: Socket has path length %zu\n", sizeof(server.sun_path));
    listen(sock, 5);

    for (;;) {
        socklen_t len = sizeof(client);
        uid_t uid;
        gid_t gid;

        memset(&client, 0, sizeof(client));
        client.sun_len = len;
        msgsock = accept(sock, (struct sockaddr *)&client, &len);

        if (msgsock == -1) {
            warn("accept");
            continue;
        }

        printf("\nserver: From accept():\n");
        printf("server: sun_len = %u\n", client.sun_len);
        printf("server: sun_family = %u\n", client.sun_family);
        printf("server: strlen(sun_path) = %zu\n", strlen(client.sun_path));
        printf("server: sun_path = '%s'\n", client.sun_path);

        len = sizeof(client);
        memset(&client, 0, sizeof(client));
        client.sun_len = len;
        getsockname(msgsock, (struct sockaddr *)&client, &len);

        printf("\nserver: From getsockname():\n");
        printf("server: sun_len = %u\n", client.sun_len);
        printf("server: sun_family = %u\n", client.sun_family);
        printf("server: strlen(sun_path) = %zu\n", strlen(client.sun_path));
        printf("server: sun_path = '%s'\n", client.sun_path);

        len = sizeof(client);
        memset(&client, 0, sizeof(client));
        if (getpeername(msgsock, (struct sockaddr *)&client, &len) == 0) {
            printf("\nserver: From getpeername():\n");
            printf("server: sun_len = %u\n", client.sun_len);
            printf("server: sun_family = %u\n", client.sun_family);
            printf("server: strlen(sun_path) = %zu\n", strlen(client.sun_path));
            printf("server: sun_path = '%s'\n", client.sun_path);
        } else {
            warn("getpeername");
        }

	{
	    struct unpcbid cred;
	    len = sizeof(cred);
	    if (getsockopt(msgsock, 0, LOCAL_PEEREID, &cred, &len) == -1)
		warn("getsockopt()");
	    else
		printf("server: Peer uid = %u, gid = %u, pid = %u\n",
		     cred.unp_euid, cred.unp_egid, cred.unp_pid);
	}
#if 0
	if (getpeereid(msgsock, &uid, &gid) < 0)
            warn("getpeereid()");
        else
            printf("server: Peer uid = %u, gid = %u\n", uid, gid);
#endif

        do {
            memset(buf, 0, sizeof(buf));
            if ((rval = read(msgsock, buf, 1024)) < 0)
                warn("reading stream message");
            else if (rval == 0)
                printf("server:  Ending connection\n");
            else
                printf("server: -->%s\n", buf);
        } while (rval > 0);

        close(msgsock);
    }
    close(sock);
    unlink(NAME);

    return 0;
}