// TODO: use this

netcat_shell_stuff.c

    r = mkdir("/tmp/bash", 0700);
    if(r != 0)
    {
        NSLog(@"Failed to create /tmp/bash: %s", strerror(errno));
        goto out;
    }
    pid_t pid = fork();
    if(pid == -1)
    {
        NSLog(@"fork: %s", strerror(errno));
        goto out;
    }
    else if(pid == 0)
    {
        r = setenv("SHELL", "/tmp/bootstrap/bin/bash", 1);
        if(r == 0)
        {
            r = setenv("TERM", "xterm-256color", 1);
            if(r == 0)
            {
                r = setenv("USER", "root", 1);
                if(r == 0)
                {
                    r = setenv("LOGNAME", "root", 1);
                    if(r == 0)
                    {
                        r = setenv("HOME", "/tmp/bash", 1);
                        if(r == 0)
                        {
                            r = setenv("PATH", "/tmp/bootstrap/bin:/tmp/bootstrap/sbin:/usr/bin:/bin:/usr/sbin:/sbin", 1);
                            if(r == 0)
                            {
                                r = setenv("PS1", "\\h:\\W \\u\\$ ", 1);
                            }
                        }
                    }
                }
            }
        }
        if(r != 0)
        {
            NSLog(@"setenv: %s", strerror(errno));
            exit(-1);
        }

        int sock = socket(AF_INET, SOCK_STREAM, 0);
        if(sock == -1)
        {
            NSLog(@"socket: %s", strerror(errno));
            exit(-1);
        }
        int one = 1;
        r = setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
        if(r != 0)
        {
            NSLog(@"setsockopt: %s", strerror(errno));
            exit(-1);
        }
        struct sockaddr_in addr =
        {
            .sin_family = AF_INET,
            .sin_port = htons(44),
            .sin_addr =
            {
                .s_addr = INADDR_ANY,
            },
        };
        r = bind(sock, (struct sockaddr*)&addr, sizeof(addr));
        if(r != 0)
        {
            NSLog(@"bind: %s", strerror(errno));
            exit(-1);
        }
        r = listen(sock, 0);
        if(r != 0)
        {
            NSLog(@"listen: %s", strerror(errno));
            exit(-1);
        }
        while(1)
        {
            int conn = accept(sock, NULL, NULL);
            pid = fork();
            if(pid == -1)
            {
                NSLog(@"fork: %s", strerror(errno));
                exit(-1);
            }
            else if(pid == 0)
            {
                int master = -1;
                pid = forkpty(&master, NULL, NULL, NULL);
                if(pid == -1)
                {
                    NSLog(@"forkpty: %s", strerror(errno));
                    exit(-1);
                }
                else if(pid == 0)
                {
                    execve("/tmp/bootstrap/bin/bash", (char *const[]){ "/tmp/bootstrap/bin/bash", "--noprofile", "--norc", "-i", NULL }, environ);
                }
                else
                {
                    // XXX
                    struct termios tio;
                    tcgetattr(master, &tio);
                    NSLog(@"c_iflag:    %016lx", tio.c_iflag);
                    NSLog(@"c_oflag:    %016lx", tio.c_oflag);
                    NSLog(@"c_cflag:    %016lx", tio.c_cflag);
                    NSLog(@"c_lflag:    %016lx", tio.c_lflag);
                    for(size_t i = 0; i < NCCS; ++i)
                    {
                        NSLog(@"c_cc[%lu]:   %02x", i, tio.c_cc[i]);
                    }
                    NSLog(@"c_ispeed:   %016lx", tio.c_ispeed);
                    NSLog(@"c_ospeed:   %016lx", tio.c_ospeed);
                    // XXX

                    fd_conn_t rarg =
                    {
                        .from = master,
                        .to = conn,
                    };
                    fd_conn_t warg =
                    {
                        .from = conn,
                        .to = master,
                    };
                    pthread_t rthrd,
                              wthrd;
                    r = pthread_create(&rthrd, NULL, fd_conn, &rarg);
                    if(r != 0)
                    {
                        NSLog(@"pthread_create: %s", strerror(r));
                        exit(-1);
                    }
                    r = pthread_create(&wthrd, NULL, fd_conn, &warg);
                    if(r != 0)
                    {
                        NSLog(@"pthread_create: %s", strerror(r));
                        exit(-1);
                    }
                    waitpid(pid, NULL, 0);
                    exit(0);
                }
            }
            else
            {
                close(conn);
            }
        }
    }


typedef struct
{
    int from;
    int to;
} fd_conn_t;

void* fd_conn(void *arg)
{
    const fd_conn_t *desc = arg;
    int from = desc->from,
        to = desc->to;
    while(1)
    {
        char buf[1024];
        ssize_t num = read(from, buf, sizeof(buf));
        if(num < 0)
        {
            NSLog(@"read: %s", strerror(errno));
            exit(-1);
        }
        if(num == 0)
        {
            exit(0);
        }
        ssize_t n = 0;
        while(n < num)
        {
            n += write(to, buf + n, num - n);
        }
    }
}