char *make_dir_path(const char *path, mode_t mode)
{
    int pos = 0;
    char *prefix;

    while (1) {
        pos += strcspn(path + pos, "/");

        if (pos > 0) {
            prefix = dupprintf("%.*s", pos, path);

            if (mkdir(prefix, mode) < 0 && errno != EEXIST) {
                char *ret = dupprintf("%s: mkdir: %s",
                                      prefix, strerror(errno));
                sfree(prefix);
                return ret;
            }

            sfree(prefix);
        }

        if (!path[pos])
            return NULL;
        pos += strspn(path + pos, "/");
    }
}

void launch_help(HWND hwnd, const char *topic)
{
    if (topic) {
	int colonpos = strcspn(topic, ":");

#ifndef NO_HTMLHELP
	if (chm_path) {
	    char *fname;
	    assert(topic[colonpos] != '\0');
	    fname = dupprintf("%s::/%s.html>main", chm_path,
			      topic + colonpos + 1);
	    p_HtmlHelpA(hwnd, fname, HH_DISPLAY_TOPIC, 0);
	    sfree(fname);
	} else
#endif /* NO_HTMLHELP */
	if (help_path) {
	    char *cmd = dupprintf("JI(`',`%.*s')", colonpos, topic);
	    WinHelp(hwnd, help_path, HELP_COMMAND, (DWORD)cmd);
	    sfree(cmd);
	}
    } else {
#ifndef NO_HTMLHELP
	if (chm_path) {
	    p_HtmlHelpA(hwnd, chm_path, HH_DISPLAY_TOPIC, 0);
	} else
#endif /* NO_HTMLHELP */
	if (help_path) {
	    WinHelp(hwnd, help_path,
		    help_has_contents ? HELP_FINDER : HELP_CONTENTS, 0);
	}
    }
    requested_help = TRUE;
}

char *make_dir_and_check_ours(const char *dirname)
{
    struct stat st;

    /*
     * Create the directory. We might have created it before, so
     * EEXIST is an OK error; but anything else is doom.
     */
    if (mkdir(dirname, 0700) < 0 && errno != EEXIST)
        return dupprintf("%s: mkdir: %s", dirname, strerror(errno));

    /*
     * Now check that that directory is _owned by us_ and not writable
     * by anybody else. This protects us against somebody else
     * previously having created the directory in a way that's
     * writable to us, and thus manipulating us into creating the
     * actual socket in a directory they can see so that they can
     * connect to it and use our authenticated SSH sessions.
     */
    if (stat(dirname, &st) < 0)
        return dupprintf("%s: stat: %s", dirname, strerror(errno));
    if (st.st_uid != getuid())
        return dupprintf("%s: directory owned by uid %d, not by us",
                         dirname, st.st_uid);
    if ((st.st_mode & 077) != 0)
        return dupprintf("%s: directory has overgenerous permissions %03o"
                         " (expected 700)", dirname, st.st_mode & 0777);

    return NULL;
}

int console_confirm_weak_crypto_primitive(
    Seat *seat, const char *algtype, const char *algname,
    void (*callback)(void *ctx, int result), void *ctx)
{
    static const char msg[] =
	"The first %s supported by the server is\n"
	"%s, which is below the configured warning threshold.\n"
	"Continue with connection? (y/n) ";

	static const char mbtitle[] = "%s Security Alert";

	int mbret;
	char *message, *title;

	message = dupprintf(msg, algtype, algname);
	title = dupprintf(mbtitle, appname);

	mbret = MessageBox(GetParentHwnd(), message, title, MB_ICONWARNING|MB_YESNO);
	sfree(message);
	sfree(title);
	if (mbret == IDYES)
		return 1;
	else
		return 0;
}

void ErrorExit(char * str) 
{ 
    LPVOID lpMsgBuf;
    char* buf;
    DWORD dw = GetLastError(); 

    FormatMessageA(
        FORMAT_MESSAGE_ALLOCATE_BUFFER | 
        FORMAT_MESSAGE_FROM_SYSTEM |
        FORMAT_MESSAGE_IGNORE_INSERTS,
        NULL,
        dw,
        MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
        (LPSTR) &lpMsgBuf,
        0, NULL );
    if (dw)
        buf = dupprintf("fatal error:%s failed with error (%d: %s)", str, dw, lpMsgBuf);
    else
        buf = dupprintf("fatal error:%s failed", str);

    MessageBoxA(WindowInterface::GetInstance()->getNativeTopWnd(), (LPCSTR)buf, "Error", MB_OK); 

    sfree(buf);
    LocalFree(lpMsgBuf);
    ExitProcess(dw); 
}

int proxy_http_negotiate (ProxySocket *p, int change)
{
    if (p->state == PROXY_STATE_NEW) {
	/* we are just beginning the proxy negotiate process,
	 * so we'll send off the initial bits of the request.
	 * for this proxy method, it's just a simple HTTP
	 * request
	 */
	char *buf, dest[512];
	char *username, *password;

	sk_getaddr(p->remote_addr, dest, lenof(dest));

	buf = dupprintf("CONNECT %s:%i HTTP/1.1\r\nHost: %s:%i\r\n",
			dest, p->remote_port, dest, p->remote_port);
	sk_write(p->sub_socket, buf, strlen(buf));
	sfree(buf);

	username = conf_get_str(p->conf, CONF_proxy_username);
	password = conf_get_str(p->conf, CONF_proxy_password);
	if (username[0] || password[0]) {
	    char *buf, *buf2;
	    int i, j, len;
	    buf = dupprintf("%s:%s", username, password);
	    len = strlen(buf);
	    buf2 = snewn(len * 4 / 3 + 100, char);
	    sprintf(buf2, "Proxy-Authorization: Basic ");
	    for (i = 0, j = strlen(buf2); i < len; i += 3, j += 4)
		base64_encode_atom((unsigned char *)(buf+i),
				   (len-i > 3 ? 3 : len-i), buf2+j);
	    strcpy(buf2+j, "\r\n");
	    sk_write(p->sub_socket, buf2, strlen(buf2));
	    sfree(buf);
	    sfree(buf2);
	}

static void mac_config(int midsession)
{
    Session *s;
    WinInfo *wi;
    Str255 mactitle;
    char *str;

    if (midsession) {
        s = mac_windowsession(FrontWindow());
    } else {  
        s = snew(Session);
        memset(s, 0, sizeof(*s));
        do_defaults(NULL, &s->cfg);
        s->hasfile = FALSE;
	s->session_closed = FALSE;
    }

    /* Copy the configuration somewhere else in case this is a *
     * reconfiguration and the user cancels the operation      */

    s->temp_cfg = s->cfg;

    if (HAVE_COLOR_QD())
	s->settings_window = GetNewCWindow(wSettings, NULL, (WindowPtr)-1);
    else
	s->settings_window = GetNewWindow(wSettings, NULL, (WindowPtr)-1);

    s->ctrlbox = ctrl_new_box();
    setup_config_box(s->ctrlbox, midsession, 0, 0);

    s->settings_ctrls.data = &s->temp_cfg;
    if (midsession)
        s->settings_ctrls.end = &mac_enddlg_reconfig;
    else
        s->settings_ctrls.end = &mac_enddlg_config;

    macctrl_layoutbox(s->ctrlbox, s->settings_window, &s->settings_ctrls);

    wi = snew(WinInfo);
    memset(wi, 0, sizeof(*wi));
    wi->s = s;
    wi->mcs = &s->settings_ctrls;
    wi->wtype = wSettings;
    wi->update = &macctrl_update;
    wi->click = &macctrl_click;
    wi->key = &macctrl_key;
    wi->activate = &macctrl_activate;
    wi->adjustmenus = &macctrl_adjustmenus;
    wi->close = &mac_closedlg;
    SetWRefCon(s->settings_window, (long)wi);
    if (midsession)
        str = dupprintf("%s Reconfiguration", appname);
    else
        str = dupprintf("%s Configuration", appname);
    c2pstrcpy(mactitle, str);
    sfree(str);
    SetWTitle(s->settings_window, mactitle);
    ShowWindow(s->settings_window);
}

/* Helper function to extract a special character from a termios. */
static char *get_ttychar(struct termios *t, int index)
{
    cc_t c = t->c_cc[index];
#if defined(_POSIX_VDISABLE)
    if (c == _POSIX_VDISABLE)
	return dupprintf("");
#endif
    return dupprintf("^<%d>", c);
}

void backend_socket_log(void *frontend, int type, SockAddr addr, int port,
                        const char *error_msg, int error_code, Conf *conf,
                        int session_started)
{
    char addrbuf[256], *msg;

    switch (type) {
      case 0:
        sk_getaddr(addr, addrbuf, lenof(addrbuf));
        if (sk_addr_needs_port(addr)) {
            msg = dupprintf("Connecting to %s port %d", addrbuf, port);
        } else {
            msg = dupprintf("Connecting to %s", addrbuf);
        }
        break;
      case 1:
        sk_getaddr(addr, addrbuf, lenof(addrbuf));
        msg = dupprintf("Failed to connect to %s: %s", addrbuf, error_msg);
        break;
      case 2:
        /* Proxy-related log messages have their own identifying
         * prefix already, put on by our caller. */
        {
            int len, log_to_term;

            /* Suffix \r\n temporarily, so we can log to the terminal. */
            msg = dupprintf("%s\r\n", error_msg);
            len = (int)strlen(msg);
            assert(len >= 2);

            log_to_term = conf_get_int(conf, CONF_proxy_log_to_term);
            if (log_to_term == AUTO)
                log_to_term = session_started ? FORCE_OFF : FORCE_ON;
            if (log_to_term == FORCE_ON)
                from_backend(frontend, TRUE, msg, len);

            msg[len-2] = '\0';         /* remove the \r\n again */
        }
        break;
      default:
        msg = NULL;  /* shouldn't happen, but placate optimiser */
        break;
    }

    if (msg) {
        logevent(frontend, msg);
        sfree(msg);
    }
}

static void raw_log(Plug plug, int type, SockAddr addr, int port,
		    const char *error_msg, int error_code)
{
    Raw raw = (Raw) plug;
    char addrbuf[256], *msg;

    sk_getaddr(addr, addrbuf, lenof(addrbuf));

    if (type == 0)
	msg = dupprintf("Connecting to %s port %d", addrbuf, port);
    else
	msg = dupprintf("Failed to connect to %s: %s", addrbuf, error_msg);

    logevent(raw->frontend, msg);
}

bool getsids(char **error)
{
#ifdef __clang__
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wmissing-braces"
#endif
    SID_IDENTIFIER_AUTHORITY world_auth = SECURITY_WORLD_SID_AUTHORITY;
    SID_IDENTIFIER_AUTHORITY nt_auth = SECURITY_NT_AUTHORITY;
#ifdef __clang__
#pragma clang diagnostic pop
#endif

    bool ret = false;

    *error = NULL;

    if (!usersid) {
        if ((usersid = get_user_sid()) == NULL) {
            *error = dupprintf("unable to construct SID for current user: %s",
                               win_strerror(GetLastError()));
            goto cleanup;
        }
    }

    if (!worldsid) {
        if (!AllocateAndInitializeSid(&world_auth, 1, SECURITY_WORLD_RID,
                                      0, 0, 0, 0, 0, 0, 0, &worldsid)) {
            *error = dupprintf("unable to construct SID for world: %s",
                               win_strerror(GetLastError()));
            goto cleanup;
        }
    }

    if (!networksid) {
        if (!AllocateAndInitializeSid(&nt_auth, 1, SECURITY_NETWORK_RID,
                                      0, 0, 0, 0, 0, 0, 0, &networksid)) {
            *error = dupprintf("unable to construct SID for "
                               "local same-user access only: %s",
                               win_strerror(GetLastError()));
            goto cleanup;
        }
    }

    ret = true;

 cleanup:
    return ret;
}

static void process_subneg(Telnet telnet)
{
    unsigned char *b, *p, *q;
    int var, value, n, bsize;
    char *e, *eval, *ekey, *user;

    switch (telnet->sb_opt) {
      case TELOPT_TSPEED:
	if (telnet->sb_len == 1 && telnet->sb_buf[0] == TELQUAL_SEND) {
	    char *logbuf;
	    char *termspeed = conf_get_str(telnet->conf, CONF_termspeed);
	    b = snewn(20 + strlen(termspeed), unsigned char);
	    b[0] = IAC;
	    b[1] = SB;
	    b[2] = TELOPT_TSPEED;
	    b[3] = TELQUAL_IS;
	    strcpy((char *)(b + 4), termspeed);
	    n = 4 + strlen(termspeed);
	    b[n] = IAC;
	    b[n + 1] = SE;
	    telnet->bufsize = sk_write(telnet->s, (char *)b, n + 2);
	    logevent(telnet->frontend, "server:\tSB TSPEED SEND");
	    logbuf = dupprintf("client:\tSB TSPEED IS %s", termspeed);
	    logevent(telnet->frontend, logbuf);
	    sfree(logbuf);
	    sfree(b);
	} else

/*
 * Set local current directory. Returns NULL on success, or else an
 * error message which must be freed after printing.
 */
char *psftp_lcd(char *dir)
{
    if (chdir(dir) < 0)
	return dupprintf("%s: chdir: %s", dir, strerror(errno));
    else
	return NULL;
}

/*
 * Trim square brackets off the outside of an IPv6 address literal.
 * Leave all other strings unchanged. Returns a fresh dynamically
 * allocated string.
 */
char *host_strduptrim(const char *s)
{
    if (s[0] == '[') {
        const char *p = s+1;
        int colons = 0;
        while (*p && *p != ']') {
            if (isxdigit((unsigned char)*p))
                /* OK */;
            else if (*p == ':')
                colons++;
            else
                break;
            p++;
        }
        if (*p == ']' && !p[1] && colons > 1) {
            /*
             * This looks like an IPv6 address literal (hex digits and
             * at least two colons, contained in square brackets).
             * Trim off the brackets.
             */
            return dupprintf("%.*s", (int)(p - (s+1)), s+1);
        }
    }

    /*
     * Any other shape of string is simply duplicated.
     */
    return dupstr(s);
}

static char *sk_handle_peer_info(Socket s)
{
    Handle_Socket ps = (Handle_Socket) s;
    ULONG pid;
    static HMODULE kernel32_module;
    DECL_WINDOWS_FUNCTION(static, BOOL, GetNamedPipeClientProcessId,
                          (HANDLE, PULONG));

    if (!kernel32_module) {
        kernel32_module = load_system32_dll("kernel32.dll");
#if (defined _MSC_VER && _MSC_VER < 1900) || defined __MINGW32__ || defined COVERITY
        /* For older Visual Studio, and MinGW too (at least as of
         * Ubuntu 16.04), this function isn't available in the header
         * files to type-check. Ditto the toolchain I use for
         * Coveritying the Windows code. */
        GET_WINDOWS_FUNCTION_NO_TYPECHECK(
            kernel32_module, GetNamedPipeClientProcessId);
#else
        GET_WINDOWS_FUNCTION(
            kernel32_module, GetNamedPipeClientProcessId);
#endif
    }

    /*
     * Of course, not all handles managed by this module will be
     * server ends of named pipes, but if they are, then it's useful
     * to log what we can find out about the client end.
     */
    if (p_GetNamedPipeClientProcessId &&
        p_GetNamedPipeClientProcessId(ps->send_H, &pid))
        return dupprintf("process id %lu", (unsigned long)pid);

    return NULL;
}

SockAddr name_lookup(const char *host,
                     int port,
                     char **canonicalname,
                     Conf *conf,
                     int addressfamily,
                     void *frontend,
                     const char *reason)
{
  char *logmsg;
  if (conf_get_int(conf, CONF_proxy_type) != PROXY_NONE && do_proxy_dns(conf) &&
      proxy_for_destination(NULL, host, port, conf)) {

    if (frontend) {
      logmsg = dupprintf("Leaving host lookup to proxy of \"%s\""
                         " (for %s)",
                         host,
                         reason);
      logevent(frontend, logmsg);
      sfree(logmsg);
    }

    *canonicalname = dupstr(host);
    return sk_nonamelookup(host);
  } else {
    if (frontend) {
      logmsg = dns_log_msg(host, addressfamily, reason);
      logevent(frontend, logmsg);
      sfree(logmsg);
    }

    return sk_namelookup(host, canonicalname, addressfamily);
  }
}

char *auth_ssh1int_challenge(AuthPolicy *ap, unsigned method, ptrlen username)
{
    /* FIXME: test returning a challenge string without \n, and ensure
     * it gets printed as a prompt in its own right, without PuTTY
     * making up a "Response: " prompt to follow it */
    return dupprintf("This is a dummy %s challenge!\n",
                     (method == AUTHMETHOD_TIS ? "TIS" : "CryptoCard"));
}

static char *dns_log_msg(const char *host, int addressfamily,
                         const char *reason)
{
    return dupprintf("Looking up host \"%s\"%s for %s", host,
                     (addressfamily == ADDRTYPE_IPV4 ? " (IPv4)" :
                      addressfamily == ADDRTYPE_IPV6 ? " (IPv6)" :
                      ""), reason);
}

int getsids(char *error)
{
    SID_IDENTIFIER_AUTHORITY world_auth = SECURITY_WORLD_SID_AUTHORITY;
    SID_IDENTIFIER_AUTHORITY nt_auth = SECURITY_NT_AUTHORITY;
    int ret;

    error=NULL;

    if (!usersid) {
        if ((usersid = get_user_sid()) == NULL) {
            error = dupprintf("unable to construct SID for current user: %s",
                               win_strerror(GetLastError()));
            goto cleanup;
        }
    }

    if (!worldsid) {
        if (!AllocateAndInitializeSid(&world_auth, 1, SECURITY_WORLD_RID,
                                      0, 0, 0, 0, 0, 0, 0, &worldsid)) {
            error = dupprintf("unable to construct SID for world: %s",
                               win_strerror(GetLastError()));
            goto cleanup;
        }
    }

    if (!networksid) {
        if (!AllocateAndInitializeSid(&nt_auth, 1, SECURITY_NETWORK_RID,
                                      0, 0, 0, 0, 0, 0, 0, &networksid)) {
            error = dupprintf("unable to construct SID for "
                               "local same-user access only: %s",
                               win_strerror(GetLastError()));
            goto cleanup;
        }
    }

    ret=TRUE;

 cleanup:
    if (ret) {
      sfree(error);
      error = NULL;
    }
    return ret;
}

static char *make_name(const char *prefix, const char *name)
{
    char *username, *retname;

    username = get_username();
    retname = dupprintf("%s.%s.%s", prefix, username, name);
    sfree(username);

    return retname;
}