//                            socket-file 0.9
//                                  by
//                           Steven L. Elliott
//
// A small C++ test program that illustrates Unix domain sockets.  This program
// has only been tested on Linux.
//
// Build  : g++ -g socket-file.cpp -o socket-file
// Indent : indent -gnu -nut -i4 -bli0 -npcs -nbad socket-file.cpp

// C headers
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/un.h>

// C++ headers
#include <iostream>
#include <sstream>

using namespace std;

int
main(int argc, char *argv[], char *envp[])
{
    int fd;
    struct sockaddr_un sa;
    string sfile;
    bool do_listen;

    if (argc != 3)
    {
        cerr << "Usage: " << argv[0] << " socket_file listen|connect" << endl;
        exit(1);
    }

    sfile = argv[1];
    do_listen = !strcmp(argv[2], "listen");

    sa.sun_family = AF_FILE;
    strcpy(sa.sun_path, sfile.c_str());
    fd = socket(PF_FILE, SOCK_STREAM, 0);
    if (fd == -1)
    {
        cerr << "socket() failed.  errno=" << errno << endl;
        exit(1);
    }

    if (do_listen)
    {
        if ((unlink(sfile.c_str()) == -1) && (errno != ENOENT))
        {
            cerr << "Could not remove socket file " << sfile << ".  errno=" <<
                errno << endl;
            exit(1);
        }

        if (bind(fd, (struct sockaddr *) &sa, sizeof(sa)) == -1)
        {
            cerr << "bind() failed.  errno=" << errno << endl;
            exit(1);
        }

        listen(fd, 5);

        struct sockaddr_storage conn_addr;
        socklen_t conn_addr_len = sizeof(conn_addr);
        int conn_fd = accept(fd, (struct sockaddr *) &conn_addr,
                             &conn_addr_len);

        char abuff[200];
        int rc;
        rc = recv(conn_fd, abuff, sizeof(abuff) - 1, 0);
        if (rc == -1)
        {
            cerr << "recv() failed.  errno=" << errno << endl;
            exit(1);
        }
        abuff[rc] = 0;
        cout << "recv: " << abuff << endl;
    }
    else
    {
        if (connect(fd, (struct sockaddr *) &sa, sizeof(sa)) == -1)
        {
            cerr << "connect() failed.  errno=" << errno << endl;
            exit(1);
        }

        stringstream to_send;
        to_send << "Sent by PID " << getpid();
        string to_send_str = to_send.str();
        if (send(fd, to_send_str.c_str(), to_send_str.length(), 0) == -1)
        {
            cerr << "Could not send.  errno=" << errno << endl;
            exit(1);
        }
        cout << "send: " << to_send_str << endl;
    }

    close(fd);
    return 0;
}