/*
 * PLink - a Windows command-line (stdin/stdout) variant of PuTTY.
 */

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <stdarg.h>

#define PUTTY_DO_GLOBALS               /* actually _define_ globals */
#include "putty.h"
#include "storage.h"
#include "tree234.h"
#include "winsecur.h"

#define WM_AGENT_CALLBACK (WM_APP + 4)

struct agent_callback {
    void (*callback)(void *, void *, int);
    void *callback_ctx;
    void *data;
    int len;
};

void cmdline_error(const char *fmt, ...)
{
    va_list ap;
    va_start(ap, fmt);
    console_print_error_msg_fmt_v("plink", fmt, ap);
    va_end(ap);
    exit(1);
}

HANDLE inhandle, outhandle, errhandle;
struct handle *stdin_handle, *stdout_handle, *stderr_handle;
handle_sink stdout_hs, stderr_hs;
StripCtrlChars *stdout_scc, *stderr_scc;
BinarySink *stdout_bs, *stderr_bs;
DWORD orig_console_mode;

WSAEVENT netevent;

static Backend *backend;
Conf *conf;

static void plink_echoedit_update(Seat *seat, bool echo, bool edit)
{
    /* Update stdin read mode to reflect changes in line discipline. */
    DWORD mode;

    mode = ENABLE_PROCESSED_INPUT;
    if (echo)
        mode = mode | ENABLE_ECHO_INPUT;
    else
        mode = mode & ~ENABLE_ECHO_INPUT;
    if (edit)
        mode = mode | ENABLE_LINE_INPUT;
    else
        mode = mode & ~ENABLE_LINE_INPUT;
    SetConsoleMode(inhandle, mode);
}

static size_t plink_output(
    Seat *seat, bool is_stderr, const void *data, size_t len)
{
    BinarySink *bs = is_stderr ? stderr_bs : stdout_bs;
    put_data(bs, data, len);

    return handle_backlog(stdout_handle) + handle_backlog(stderr_handle);
}

static bool plink_eof(Seat *seat)
{
    handle_write_eof(stdout_handle);
    return false;   /* do not respond to incoming EOF with outgoing */
}

static int plink_get_userpass_input(Seat *seat, prompts_t *p, bufchain *input)
{
    int ret;
    ret = cmdline_get_passwd_input(p);
    if (ret == -1)
        ret = console_get_userpass_input(p);
    return ret;
}

static const SeatVtable plink_seat_vt = {
    plink_output,
    plink_eof,
    plink_get_userpass_input,
    nullseat_notify_remote_exit,
    console_connection_fatal,
    nullseat_update_specials_menu,
    nullseat_get_ttymode,
    nullseat_set_busy_status,
    console_verify_ssh_host_key,
    console_confirm_weak_crypto_primitive,
    console_confirm_weak_cached_hostkey,
    nullseat_is_never_utf8,
    plink_echoedit_update,
    nullseat_get_x_display,
    nullseat_get_windowid,
    nullseat_get_window_pixel_size,
    console_stripctrl_new,
    console_set_trust_status,
};
static Seat plink_seat[1] = {{ &plink_seat_vt }};

static DWORD main_thread_id;

void agent_schedule_callback(void (*callback)(void *, void *, int),
                             void *callback_ctx, void *data, int len)
{
    struct agent_callback *c = snew(struct agent_callback);
    c->callback = callback;
    c->callback_ctx = callback_ctx;
    c->data = data;
    c->len = len;
    PostThreadMessage(main_thread_id, WM_AGENT_CALLBACK, 0, (LPARAM)c);
}

/*
 *  Short description of parameters.
 */
static void usage(void)
{
    printf("Plink: command-line connection utility\n");
    printf("%s\n", ver);
    printf("Usage: plink [options] [user@]host [command]\n");
    printf("       (\"host\" can also be a PuTTY saved session name)\n");
    printf("Options:\n");
    printf("  -V        print version information and exit\n");
    printf("  -pgpfp    print PGP key fingerprints and exit\n");
    printf("  -v        show verbose messages\n");
    printf("  -load sessname  Load settings from saved session\n");
    printf("  -ssh -telnet -rlogin -raw -serial\n");
    printf("            force use of a particular protocol\n");
    printf("  -P port   connect to specified port\n");
    printf("  -l user   connect with specified username\n");
    printf("  -batch    disable all interactive prompts\n");
    printf("  -proxycmd command\n");
    printf("            use 'command' as local proxy\n");
    printf("  -sercfg configuration-string (e.g. 19200,8,n,1,X)\n");
    printf("            Specify the serial configuration (serial only)\n");
    printf("The following options only apply to SSH connections:\n");
    printf("  -pw passw login with specified password\n");
    printf("  -D [listen-IP:]listen-port\n");
    printf("            Dynamic SOCKS-based port forwarding\n");
    printf("  -L [listen-IP:]listen-port:host:port\n");
    printf("            Forward local port to remote address\n");
    printf("  -R [listen-IP:]listen-port:host:port\n");
    printf("            Forward remote port to local address\n");
    printf("  -X -x     enable / disable X11 forwarding\n");
    printf("  -A -a     enable / disable agent forwarding\n");
    printf("  -t -T     enable / disable pty allocation\n");
    printf("  -1 -2     force use of particular protocol version\n");
    printf("  -4 -6     force use of IPv4 or IPv6\n");
    printf("  -C        enable compression\n");
    printf("  -i key    private key file for user authentication\n");
    printf("  -noagent  disable use of Pageant\n");
    printf("  -agent    enable use of Pageant\n");
    printf("  -noshare  disable use of connection sharing\n");
    printf("  -share    enable use of connection sharing\n");
    printf("  -hostkey aa:bb:cc:...\n");
    printf("            manually specify a host key (may be repeated)\n");
    printf("  -sanitise-stderr, -sanitise-stdout, "
           "-no-sanitise-stderr, -no-sanitise-stdout\n");
    printf("            do/don't strip control chars from standard "
           "output/error\n");
    printf("  -no-antispoof   omit anti-spoofing prompt after "
           "authentication\n");
    printf("  -m file   read remote command(s) from file\n");
    printf("  -s        remote command is an SSH subsystem (SSH-2 only)\n");
    printf("  -N        don't start a shell/command (SSH-2 only)\n");
    printf("  -nc host:port\n");
    printf("            open tunnel in place of session (SSH-2 only)\n");
    printf("  -sshlog file\n");
    printf("  -sshrawlog file\n");
    printf("            log protocol details to a file\n");
    printf("  -shareexists\n");
    printf("            test whether a connection-sharing upstream exists\n");
    exit(1);
}

static void version(void)
{
    char *buildinfo_text = buildinfo("\n");
    printf("plink: %s\n%s\n", ver, buildinfo_text);
    sfree(buildinfo_text);
    exit(0);
}

char *do_select(SOCKET skt, bool startup)
{
    int events;
    if (startup) {
        events = (FD_CONNECT | FD_READ | FD_WRITE |
                  FD_OOB | FD_CLOSE | FD_ACCEPT);
    } else {
        events = 0;
    }
    if (p_WSAEventSelect(skt, netevent, events) == SOCKET_ERROR) {
        switch (p_WSAGetLastError()) {
          case WSAENETDOWN:
            return "Network is down";
          default:
            return "WSAEventSelect(): unknown error";
        }
    }
    return NULL;
}

size_t stdin_gotdata(struct handle *h, const void *data, size_t len, int err)
{
    if (err) {
        char buf[4096];
        FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM, NULL, err, 0,
                      buf, lenof(buf), NULL);
        buf[lenof(buf)-1] = '\0';
        if (buf[strlen(buf)-1] == '\n')
            buf[strlen(buf)-1] = '\0';
        fprintf(stderr, "Unable to read from standard input: %s\n", buf);
        cleanup_exit(0);
    }

    noise_ultralight(NOISE_SOURCE_IOLEN, len);
    if (backend_connected(backend)) {
        if (len > 0) {
            return backend_send(backend, data, len);
        } else {
            backend_special(backend, SS_EOF, 0);
            return 0;
        }
    } else
        return 0;
}

void stdouterr_sent(struct handle *h, size_t new_backlog, int err)
{
    if (err) {
        char buf[4096];
        FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM, NULL, err, 0,
                      buf, lenof(buf), NULL);
        buf[lenof(buf)-1] = '\0';
        if (buf[strlen(buf)-1] == '\n')
            buf[strlen(buf)-1] = '\0';
        fprintf(stderr, "Unable to write to standard %s: %s\n",
                (h == stdout_handle ? "output" : "error"), buf);
        cleanup_exit(0);
    }

    if (backend_connected(backend)) {
        backend_unthrottle(backend, (handle_backlog(stdout_handle) +
                                     handle_backlog(stderr_handle)));
    }
}

const bool share_can_be_downstream = true;
const bool share_can_be_upstream = true;

int main(int argc, char **argv)
{
    bool sending;
    SOCKET *sklist;
    size_t skcount, sksize;
    int exitcode;
    bool errors;
    bool use_subsystem = false;
    bool just_test_share_exists = false;
    enum TriState sanitise_stdout = AUTO, sanitise_stderr = AUTO;
    unsigned long now, next, then;
    const struct BackendVtable *vt;

    dll_hijacking_protection();

    sklist = NULL;
    skcount = sksize = 0;
    /*
     * Initialise port and protocol to sensible defaults. (These
     * will be overridden by more or less anything.)
     */
    default_protocol = PROT_SSH;
    default_port = 22;

    flags = 0;
    cmdline_tooltype |=
        (TOOLTYPE_HOST_ARG |
         TOOLTYPE_HOST_ARG_CAN_BE_SESSION |
         TOOLTYPE_HOST_ARG_PROTOCOL_PREFIX |
         TOOLTYPE_HOST_ARG_FROM_LAUNCHABLE_LOAD);

    /*
     * Process the command line.
     */
    conf = conf_new();
    do_defaults(NULL, conf);
    loaded_session = false;
    default_protocol = conf_get_int(conf, CONF_protocol);
    default_port = conf_get_int(conf, CONF_port);
    errors = false;
    {
        /*
         * Override the default protocol if PLINK_PROTOCOL is set.
         */
        char *p = getenv("PLINK_PROTOCOL");
        if (p) {
            const struct BackendVtable *vt = backend_vt_from_name(p);
            if (vt) {
                default_protocol = vt->protocol;
                default_port = vt->default_port;
                conf_set_int(conf, CONF_protocol, default_protocol);
                conf_set_int(conf, CONF_port, default_port);
            }
        }
    }
    while (--argc) {
        char *p = *++argv;
        int ret = cmdline_process_param(p, (argc > 1 ? argv[1] : NULL),
                                        1, conf);
        if (ret == -2) {
            fprintf(stderr,
                    "plink: option \"%s\" requires an argument\n", p);
            errors = true;
        } else if (ret == 2) {
            --argc, ++argv;
        } else if (ret == 1) {
            continue;
        } else if (!strcmp(p, "-batch")) {
            console_batch_mode = true;
        } else if (!strcmp(p, "-s")) {
            /* Save status to write to conf later. */
            use_subsystem = true;
        } else if (!strcmp(p, "-V") || !strcmp(p, "--version")) {
            version();
        } else if (!strcmp(p, "--help")) {
            usage();
        } else if (!strcmp(p, "-pgpfp")) {
            pgp_fingerprints();
            exit(1);
        } else if (!strcmp(p, "-shareexists")) {
            just_test_share_exists = true;
        } else if (!strcmp(p, "-sanitise-stdout") ||
                   !strcmp(p, "-sanitize-stdout")) {
            sanitise_stdout = FORCE_ON;
        } else if (!strcmp(p, "-no-sanitise-stdout") ||
                   !strcmp(p, "-no-sanitize-stdout")) {
            sanitise_stdout = FORCE_OFF;
        } else if (!strcmp(p, "-sanitise-stderr") ||
                   !strcmp(p, "-sanitize-stderr")) {
            sanitise_stderr = FORCE_ON;
        } else if (!strcmp(p, "-no-sanitise-stderr") ||
                   !strcmp(p, "-no-sanitize-stderr")) {
            sanitise_stderr = FORCE_OFF;
        } else if (!strcmp(p, "-no-antispoof")) {
            console_antispoof_prompt = false;
        } else if (*p != '-') {
            strbuf *cmdbuf = strbuf_new();

            while (argc > 0) {
                if (cmdbuf->len > 0)
                    put_byte(cmdbuf, ' '); /* add space separator */
                put_datapl(cmdbuf, ptrlen_from_asciz(p));
                if (--argc > 0)
                    p = *++argv;
            }

            conf_set_str(conf, CONF_remote_cmd, cmdbuf->s);
            conf_set_str(conf, CONF_remote_cmd2, "");
            conf_set_bool(conf, CONF_nopty, true);  /* command => no tty */

            strbuf_free(cmdbuf);
            break;                     /* done with cmdline */
        } else {
            fprintf(stderr, "plink: unknown option \"%s\"\n", p);
            errors = true;
        }
    }

    if (errors)
        return 1;

    if (!cmdline_host_ok(conf)) {
        usage();
    }

    prepare_session(conf);

    /*
     * Perform command-line overrides on session configuration.
     */
    cmdline_run_saved(conf);

    /*
     * Apply subsystem status.
     */
    if (use_subsystem)
        conf_set_bool(conf, CONF_ssh_subsys, true);

    if (!*conf_get_str(conf, CONF_remote_cmd) &&
        !*conf_get_str(conf, CONF_remote_cmd2) &&
        !*conf_get_str(conf, CONF_ssh_nc_host))
        flags |= FLAG_INTERACTIVE;

    /*
     * Select protocol. This is farmed out into a table in a
     * separate file to enable an ssh-free variant.
     */
    vt = backend_vt_from_proto(conf_get_int(conf, CONF_protocol));
    if (vt == NULL) {
        fprintf(stderr,
                "Internal fault: Unsupported protocol found\n");
        return 1;
    }

    sk_init();
    if (p_WSAEventSelect == NULL) {
        fprintf(stderr, "Plink requires WinSock 2\n");
        return 1;
    }

    /*
     * Plink doesn't provide any way to add forwardings after the
     * connection is set up, so if there are none now, we can safely set
     * the "simple" flag.
     */
    if (conf_get_int(conf, CONF_protocol) == PROT_SSH &&
        !conf_get_bool(conf, CONF_x11_forward) &&
        !conf_get_bool(conf, CONF_agentfwd) &&
        !conf_get_str_nthstrkey(conf, CONF_portfwd, 0))
        conf_set_bool(conf, CONF_ssh_simple, true);

    logctx = log_init(default_logpolicy, conf);

    if (just_test_share_exists) {
        if (!vt->test_for_upstream) {
            fprintf(stderr, "Connection sharing not supported for connection "
                    "type '%s'\n", vt->name);
            return 1;
        }
        if (vt->test_for_upstream(conf_get_str(conf, CONF_host),
                                  conf_get_int(conf, CONF_port), conf))
            return 0;
        else
            return 1;
    }

    if (restricted_acl) {
        lp_eventlog(default_logpolicy, "Running with restricted process ACL");
    }

    inhandle = GetStdHandle(STD_INPUT_HANDLE);
    outhandle = GetStdHandle(STD_OUTPUT_HANDLE);
    errhandle = GetStdHandle(STD_ERROR_HANDLE);

    /*
     * Turn off ECHO and LINE input modes. We don't care if this
     * call fails, because we know we aren't necessarily running in
     * a console.
     */
    GetConsoleMode(inhandle, &orig_console_mode);
    SetConsoleMode(inhandle, ENABLE_PROCESSED_INPUT);

    /*
     * Pass the output handles to the handle-handling subsystem.
     * (The input one we leave until we're through the
     * authentication process.)
     */
    stdout_handle = handle_output_new(outhandle, stdouterr_sent, NULL, 0);
    stderr_handle = handle_output_new(errhandle, stdouterr_sent, NULL, 0);
    handle_sink_init(&stdout_hs, stdout_handle);
    handle_sink_init(&stderr_hs, stderr_handle);
    stdout_bs = BinarySink_UPCAST(&stdout_hs);
    stderr_bs = BinarySink_UPCAST(&stderr_hs);

    /*
     * Decide whether to sanitise control sequences out of standard
     * output and standard error.
     *
     * If we weren't given a command-line override, we do this if (a)
     * the fd in question is pointing at a console, and (b) we aren't
     * trying to allocate a terminal as part of the session.
     *
     * (Rationale: the risk of control sequences is that they cause
     * confusion when sent to a local console, so if there isn't one,
     * no problem. Also, if we allocate a remote terminal, then we
     * sent a terminal type, i.e. we told it what kind of escape
     * sequences we _like_, i.e. we were expecting to receive some.)
     */
    if (sanitise_stdout == FORCE_ON ||
        (sanitise_stdout == AUTO && is_console_handle(outhandle) &&
         conf_get_bool(conf, CONF_nopty))) {
        stdout_scc = stripctrl_new(stdout_bs, true, L'\0');
        stdout_bs = BinarySink_UPCAST(stdout_scc);
    }
    if (sanitise_stderr == FORCE_ON ||
        (sanitise_stderr == AUTO && is_console_handle(errhandle) &&
         conf_get_bool(conf, CONF_nopty))) {
        stderr_scc = stripctrl_new(stderr_bs, true, L'\0');
        stderr_bs = BinarySink_UPCAST(stderr_scc);
    }

    /*
     * Start up the connection.
     */
    netevent = CreateEvent(NULL, false, false, NULL);
    {
        const char *error;
        char *realhost;
        /* nodelay is only useful if stdin is a character device (console) */
        bool nodelay = conf_get_bool(conf, CONF_tcp_nodelay) &&
            (GetFileType(GetStdHandle(STD_INPUT_HANDLE)) == FILE_TYPE_CHAR);

        error = backend_init(vt, plink_seat, &backend, logctx, conf,
                             conf_get_str(conf, CONF_host),
                             conf_get_int(conf, CONF_port),
                             &realhost, nodelay,
                             conf_get_bool(conf, CONF_tcp_keepalives));
        if (error) {
            fprintf(stderr, "Unable to open connection:\n%s", error);
            return 1;
        }
        sfree(realhost);
    }

    main_thread_id = GetCurrentThreadId();

    sending = false;

    now = GETTICKCOUNT();

    while (1) {
        int nhandles;
        HANDLE *handles;
        int n;
        DWORD ticks;

        if (!sending && backend_sendok(backend)) {
            stdin_handle = handle_input_new(inhandle, stdin_gotdata, NULL,
                                            0);
            sending = true;
        }

        if (toplevel_callback_pending()) {
            ticks = 0;
            next = now;
        } else if (run_timers(now, &next)) {
            then = now;
            now = GETTICKCOUNT();
            if (now - then > next - then)
                ticks = 0;
            else
                ticks = next - now;
        } else {
            ticks = INFINITE;
            /* no need to initialise next here because we can never
             * get WAIT_TIMEOUT */
        }

        handles = handle_get_events(&nhandles);
        handles = sresize(handles, nhandles+1, HANDLE);
        handles[nhandles] = netevent;
        n = MsgWaitForMultipleObjects(nhandles+1, handles, false, ticks,
                                      QS_POSTMESSAGE);
        if ((unsigned)(n - WAIT_OBJECT_0) < (unsigned)nhandles) {
            handle_got_event(handles[n - WAIT_OBJECT_0]);
        } else if (n == WAIT_OBJECT_0 + nhandles) {
            WSANETWORKEVENTS things;
            SOCKET socket;
            int i, socketstate;

            /*
             * We must not call select_result() for any socket
             * until we have finished enumerating within the tree.
             * This is because select_result() may close the socket
             * and modify the tree.
             */
            /* Count the active sockets. */
            i = 0;
            for (socket = first_socket(&socketstate);
                 socket != INVALID_SOCKET;
                 socket = next_socket(&socketstate)) i++;

            /* Expand the buffer if necessary. */
            sgrowarray(sklist, sksize, i);

            /* Retrieve the sockets into sklist. */
            skcount = 0;
            for (socket = first_socket(&socketstate);
                 socket != INVALID_SOCKET;
                 socket = next_socket(&socketstate)) {
                sklist[skcount++] = socket;
            }

            /* Now we're done enumerating; go through the list. */
            for (i = 0; i < skcount; i++) {
                WPARAM wp;
                socket = sklist[i];
                wp = (WPARAM) socket;
                if (!p_WSAEnumNetworkEvents(socket, NULL, &things)) {
                    static const struct { int bit, mask; } eventtypes[] = {
                        {FD_CONNECT_BIT, FD_CONNECT},
                        {FD_READ_BIT, FD_READ},
                        {FD_CLOSE_BIT, FD_CLOSE},
                        {FD_OOB_BIT, FD_OOB},
                        {FD_WRITE_BIT, FD_WRITE},
                        {FD_ACCEPT_BIT, FD_ACCEPT},
                    };
                    int e;

                    noise_ultralight(NOISE_SOURCE_IOID, socket);

                    for (e = 0; e < lenof(eventtypes); e++)
                        if (things.lNetworkEvents & eventtypes[e].mask) {
                            LPARAM lp;
                            int err = things.iErrorCode[eventtypes[e].bit];
                            lp = WSAMAKESELECTREPLY(eventtypes[e].mask, err);
                            select_result(wp, lp);
                        }
                }
            }
        } else if (n == WAIT_OBJECT_0 + nhandles + 1) {
            MSG msg;
            while (PeekMessage(&msg, INVALID_HANDLE_VALUE,
                               WM_AGENT_CALLBACK, WM_AGENT_CALLBACK,
                               PM_REMOVE)) {
                struct agent_callback *c = (struct agent_callback *)msg.lParam;
                c->callback(c->callback_ctx, c->data, c->len);
                sfree(c);
            }
        }

        run_toplevel_callbacks();

        if (n == WAIT_TIMEOUT) {
            now = next;
        } else {
            now = GETTICKCOUNT();
        }

        sfree(handles);

        if (sending)
            handle_unthrottle(stdin_handle, backend_sendbuffer(backend));

        if (!backend_connected(backend) &&
            handle_backlog(stdout_handle) + handle_backlog(stderr_handle) == 0)
            break;                     /* we closed the connection */
    }
    exitcode = backend_exitcode(backend);
    if (exitcode < 0) {
        fprintf(stderr, "Remote process exit code unavailable\n");
        exitcode = 1;                  /* this is an error condition */
    }
    cleanup_exit(exitcode);
    return 0;                          /* placate compiler warning */
}
