git.distorted.org.uk Git - u/mdw/putty/blob - windows/winplink.c

   1 /*
   2  * PLink - a Windows command-line (stdin/stdout) variant of PuTTY.
   3  */
   4
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7 #include <assert.h>
   8 #include <stdarg.h>
   9
  10 #define PUTTY_DO_GLOBALS               /* actually _define_ globals */
  11 #include "putty.h"
  12 #include "storage.h"
  13 #include "tree234.h"
  14
  15 #define WM_AGENT_CALLBACK (WM_APP + 4)
  16
  17 struct agent_callback {
  18     void (*callback)(void *, void *, int);
  19     void *callback_ctx;
  20     void *data;
  21     int len;
  22 };
  23
  24 void fatalbox(char *p, ...)
  25 {
  26     va_list ap;
  27     fprintf(stderr, "FATAL ERROR: ");
  28     va_start(ap, p);
  29     vfprintf(stderr, p, ap);
  30     va_end(ap);
  31     fputc('\n', stderr);
  32     if (logctx) {
  33         log_free(logctx);
  34         logctx = NULL;
  35     }
  36     cleanup_exit(1);
  37 }
  38 void modalfatalbox(char *p, ...)
  39 {
  40     va_list ap;
  41     fprintf(stderr, "FATAL ERROR: ");
  42     va_start(ap, p);
  43     vfprintf(stderr, p, ap);
  44     va_end(ap);
  45     fputc('\n', stderr);
  46     if (logctx) {
  47         log_free(logctx);
  48         logctx = NULL;
  49     }
  50     cleanup_exit(1);
  51 }
  52 void nonfatal(char *p, ...)
  53 {
  54     va_list ap;
  55     fprintf(stderr, "ERROR: ");
  56     va_start(ap, p);
  57     vfprintf(stderr, p, ap);
  58     va_end(ap);
  59     fputc('\n', stderr);
  60     if (logctx) {
  61         log_free(logctx);
  62         logctx = NULL;
  63     }
  64 }
  65 void connection_fatal(void *frontend, char *p, ...)
  66 {
  67     va_list ap;
  68     fprintf(stderr, "FATAL ERROR: ");
  69     va_start(ap, p);
  70     vfprintf(stderr, p, ap);
  71     va_end(ap);
  72     fputc('\n', stderr);
  73     if (logctx) {
  74         log_free(logctx);
  75         logctx = NULL;
  76     }
  77     cleanup_exit(1);
  78 }
  79 void cmdline_error(char *p, ...)
  80 {
  81     va_list ap;
  82     fprintf(stderr, "plink: ");
  83     va_start(ap, p);
  84     vfprintf(stderr, p, ap);
  85     va_end(ap);
  86     fputc('\n', stderr);
  87     exit(1);
  88 }
  89
  90 HANDLE inhandle, outhandle, errhandle;
  91 struct handle *stdin_handle, *stdout_handle, *stderr_handle;
  92 DWORD orig_console_mode;
  93 int connopen;
  94
  95 WSAEVENT netevent;
  96
  97 static Backend *back;
  98 static void *backhandle;
  99 static Conf *conf;
 100
 101 int term_ldisc(Terminal *term, int mode)
 102 {
 103     return FALSE;
 104 }
 105 void ldisc_update(void *frontend, int echo, int edit)
 106 {
 107     /* Update stdin read mode to reflect changes in line discipline. */
 108     DWORD mode;
 109
 110     mode = ENABLE_PROCESSED_INPUT;
 111     if (echo)
 112         mode = mode | ENABLE_ECHO_INPUT;
 113     else
 114         mode = mode & ~ENABLE_ECHO_INPUT;
 115     if (edit)
 116         mode = mode | ENABLE_LINE_INPUT;
 117     else
 118         mode = mode & ~ENABLE_LINE_INPUT;
 119     SetConsoleMode(inhandle, mode);
 120 }
 121
 122 char *get_ttymode(void *frontend, const char *mode) { return NULL; }
 123
 124 int from_backend(void *frontend_handle, int is_stderr,
 125                  const char *data, int len)
 126 {
 127     if (is_stderr) {
 128         handle_write(stderr_handle, data, len);
 129     } else {
 130         handle_write(stdout_handle, data, len);
 131     }
 132
 133     return handle_backlog(stdout_handle) + handle_backlog(stderr_handle);
 134 }
 135
 136 int from_backend_untrusted(void *frontend_handle, const char *data, int len)
 137 {
 138     /*
 139      * No "untrusted" output should get here (the way the code is
 140      * currently, it's all diverted by FLAG_STDERR).
 141      */
 142     assert(!"Unexpected call to from_backend_untrusted()");
 143     return 0; /* not reached */
 144 }
 145
 146 int from_backend_eof(void *frontend_handle)
 147 {
 148     handle_write_eof(stdout_handle);
 149     return FALSE;   /* do not respond to incoming EOF with outgoing */
 150 }
 151
 152 int get_userpass_input(prompts_t *p, unsigned char *in, int inlen)
 153 {
 154     int ret;
 155     ret = cmdline_get_passwd_input(p, in, inlen);
 156     if (ret == -1)
 157         ret = console_get_userpass_input(p, in, inlen);
 158     return ret;
 159 }
 160
 161 static DWORD main_thread_id;
 162
 163 void agent_schedule_callback(void (*callback)(void *, void *, int),
 164                              void *callback_ctx, void *data, int len)
 165 {
 166     struct agent_callback *c = snew(struct agent_callback);
 167     c->callback = callback;
 168     c->callback_ctx = callback_ctx;
 169     c->data = data;
 170     c->len = len;
 171     PostThreadMessage(main_thread_id, WM_AGENT_CALLBACK, 0, (LPARAM)c);
 172 }
 173
 174 /*
 175  *  Short description of parameters.
 176  */
 177 static void usage(void)
 178 {
 179     printf("PuTTY Link: command-line connection utility\n");
 180     printf("%s\n", ver);
 181     printf("Usage: plink [options] [user@]host [command]\n");
 182     printf("       (\"host\" can also be a PuTTY saved session name)\n");
 183     printf("Options:\n");
 184     printf("  -V        print version information and exit\n");
 185     printf("  -pgpfp    print PGP key fingerprints and exit\n");
 186     printf("  -v        show verbose messages\n");
 187     printf("  -load sessname  Load settings from saved session\n");
 188     printf("  -ssh -telnet -rlogin -raw -serial\n");
 189     printf("            force use of a particular protocol\n");
 190     printf("  -P port   connect to specified port\n");
 191     printf("  -l user   connect with specified username\n");
 192     printf("  -batch    disable all interactive prompts\n");
 193     printf("The following options only apply to SSH connections:\n");
 194     printf("  -pw passw login with specified password\n");
 195     printf("  -D [listen-IP:]listen-port\n");
 196     printf("            Dynamic SOCKS-based port forwarding\n");
 197     printf("  -L [listen-IP:]listen-port:host:port\n");
 198     printf("            Forward local port to remote address\n");
 199     printf("  -R [listen-IP:]listen-port:host:port\n");
 200     printf("            Forward remote port to local address\n");
 201     printf("  -X -x     enable / disable X11 forwarding\n");
 202     printf("  -A -a     enable / disable agent forwarding\n");
 203     printf("  -t -T     enable / disable pty allocation\n");
 204     printf("  -1 -2     force use of particular protocol version\n");
 205     printf("  -4 -6     force use of IPv4 or IPv6\n");
 206     printf("  -C        enable compression\n");
 207     printf("  -i key    private key file for authentication\n");
 208     printf("  -noagent  disable use of Pageant\n");
 209     printf("  -agent    enable use of Pageant\n");
 210     printf("  -m file   read remote command(s) from file\n");
 211     printf("  -s        remote command is an SSH subsystem (SSH-2 only)\n");
 212     printf("  -N        don't start a shell/command (SSH-2 only)\n");
 213     printf("  -nc host:port\n");
 214     printf("            open tunnel in place of session (SSH-2 only)\n");
 215     printf("  -sercfg configuration-string (e.g. 19200,8,n,1,X)\n");
 216     printf("            Specify the serial configuration (serial only)\n");
 217     exit(1);
 218 }
 219
 220 static void version(void)
 221 {
 222     printf("plink: %s\n", ver);
 223     exit(1);
 224 }
 225
 226 char *do_select(SOCKET skt, int startup)
 227 {
 228     int events;
 229     if (startup) {
 230         events = (FD_CONNECT | FD_READ | FD_WRITE |
 231                   FD_OOB | FD_CLOSE | FD_ACCEPT);
 232     } else {
 233         events = 0;
 234     }
 235     if (p_WSAEventSelect(skt, netevent, events) == SOCKET_ERROR) {
 236         switch (p_WSAGetLastError()) {
 237           case WSAENETDOWN:
 238             return "Network is down";
 239           default:
 240             return "WSAEventSelect(): unknown error";
 241         }
 242     }
 243     return NULL;
 244 }
 245
 246 int stdin_gotdata(struct handle *h, void *data, int len)
 247 {
 248     if (len < 0) {
 249         /*
 250          * Special case: report read error.
 251          */
 252         char buf[4096];
 253         FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM, NULL, -len, 0,
 254                       buf, lenof(buf), NULL);
 255         buf[lenof(buf)-1] = '\0';
 256         if (buf[strlen(buf)-1] == '\n')
 257             buf[strlen(buf)-1] = '\0';
 258         fprintf(stderr, "Unable to read from standard input: %s\n", buf);
 259         cleanup_exit(0);
 260     }
 261     noise_ultralight(len);
 262     if (connopen && back->connected(backhandle)) {
 263         if (len > 0) {
 264             return back->send(backhandle, data, len);
 265         } else {
 266             back->special(backhandle, TS_EOF);
 267             return 0;
 268         }
 269     } else
 270         return 0;
 271 }
 272
 273 void stdouterr_sent(struct handle *h, int new_backlog)
 274 {
 275     if (new_backlog < 0) {
 276         /*
 277          * Special case: report write error.
 278          */
 279         char buf[4096];
 280         FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM, NULL, -new_backlog, 0,
 281                       buf, lenof(buf), NULL);
 282         buf[lenof(buf)-1] = '\0';
 283         if (buf[strlen(buf)-1] == '\n')
 284             buf[strlen(buf)-1] = '\0';
 285         fprintf(stderr, "Unable to write to standard %s: %s\n",
 286                 (h == stdout_handle ? "output" : "error"), buf);
 287         cleanup_exit(0);
 288     }
 289     if (connopen && back->connected(backhandle)) {
 290         back->unthrottle(backhandle, (handle_backlog(stdout_handle) +
 291                                       handle_backlog(stderr_handle)));
 292     }
 293 }
 294
 295 int main(int argc, char **argv)
 296 {
 297     int sending;
 298     int portnumber = -1;
 299     SOCKET *sklist;
 300     int skcount, sksize;
 301     int exitcode;
 302     int errors;
 303     int got_host = FALSE;
 304     int use_subsystem = 0;
 305     unsigned long now, next, then;
 306
 307     sklist = NULL;
 308     skcount = sksize = 0;
 309     /*
 310      * Initialise port and protocol to sensible defaults. (These
 311      * will be overridden by more or less anything.)
 312      */
 313     default_protocol = PROT_SSH;
 314     default_port = 22;
 315
 316     flags = FLAG_STDERR;
 317     /*
 318      * Process the command line.
 319      */
 320     conf = conf_new();
 321     do_defaults(NULL, conf);
 322     loaded_session = FALSE;
 323     default_protocol = conf_get_int(conf, CONF_protocol);
 324     default_port = conf_get_int(conf, CONF_port);
 325     errors = 0;
 326     {
 327         /*
 328          * Override the default protocol if PLINK_PROTOCOL is set.
 329          */
 330         char *p = getenv("PLINK_PROTOCOL");
 331         if (p) {
 332             const Backend *b = backend_from_name(p);
 333             if (b) {
 334                 default_protocol = b->protocol;
 335                 default_port = b->default_port;
 336                 conf_set_int(conf, CONF_protocol, default_protocol);
 337                 conf_set_int(conf, CONF_port, default_port);
 338             }
 339         }
 340     }
 341     while (--argc) {
 342         char *p = *++argv;
 343         if (*p == '-') {
 344             int ret = cmdline_process_param(p, (argc > 1 ? argv[1] : NULL),
 345                                             1, conf);
 346             if (ret == -2) {
 347                 fprintf(stderr,
 348                         "plink: option \"%s\" requires an argument\n", p);
 349                 errors = 1;
 350             } else if (ret == 2) {
 351                 --argc, ++argv;
 352             } else if (ret == 1) {
 353                 continue;
 354             } else if (!strcmp(p, "-batch")) {
 355                 console_batch_mode = 1;
 356             } else if (!strcmp(p, "-s")) {
 357                 /* Save status to write to conf later. */
 358                 use_subsystem = 1;
 359             } else if (!strcmp(p, "-V") || !strcmp(p, "--version")) {
 360                 version();
 361             } else if (!strcmp(p, "--help")) {
 362                 usage();
 363             } else if (!strcmp(p, "-pgpfp")) {
 364                 pgp_fingerprints();
 365                 exit(1);
 366             } else {
 367                 fprintf(stderr, "plink: unknown option \"%s\"\n", p);
 368                 errors = 1;
 369             }
 370         } else if (*p) {
 371             if (!conf_launchable(conf) || !(got_host || loaded_session)) {
 372                 char *q = p;
 373                 /*
 374                  * If the hostname starts with "telnet:", set the
 375                  * protocol to Telnet and process the string as a
 376                  * Telnet URL.
 377                  */
 378                 if (!strncmp(q, "telnet:", 7)) {
 379                     char c;
 380
 381                     q += 7;
 382                     if (q[0] == '/' && q[1] == '/')
 383                         q += 2;
 384                     conf_set_int(conf, CONF_protocol, PROT_TELNET);
 385                     p = q;
 386                     while (*p && *p != ':' && *p != '/')
 387                         p++;
 388                     c = *p;
 389                     if (*p)
 390                         *p++ = '\0';
 391                     if (c == ':')
 392                         conf_set_int(conf, CONF_port, atoi(p));
 393                     else
 394                         conf_set_int(conf, CONF_port, -1);
 395                     conf_set_str(conf, CONF_host, q);
 396                     got_host = TRUE;
 397                 } else {
 398                     char *r, *user, *host;
 399                     /*
 400                      * Before we process the [user@]host string, we
 401                      * first check for the presence of a protocol
 402                      * prefix (a protocol name followed by ",").
 403                      */
 404                     r = strchr(p, ',');
 405                     if (r) {
 406                         const Backend *b;
 407                         *r = '\0';
 408                         b = backend_from_name(p);
 409                         if (b) {
 410                             default_protocol = b->protocol;
 411                             conf_set_int(conf, CONF_protocol,
 412                                          default_protocol);
 413                             portnumber = b->default_port;
 414                         }
 415                         p = r + 1;
 416                     }
 417
 418                     /*
 419                      * A nonzero length string followed by an @ is treated
 420                      * as a username. (We discount an _initial_ @.) The
 421                      * rest of the string (or the whole string if no @)
 422                      * is treated as a session name and/or hostname.
 423                      */
 424                     r = strrchr(p, '@');
 425                     if (r == p)
 426                         p++, r = NULL; /* discount initial @ */
 427                     if (r) {
 428                         *r++ = '\0';
 429                         user = p, host = r;
 430                     } else {
 431                         user = NULL, host = p;
 432                     }
 433
 434                     /*
 435                      * Now attempt to load a saved session with the
 436                      * same name as the hostname.
 437                      */
 438                     {
 439                         Conf *conf2 = conf_new();
 440                         do_defaults(host, conf2);
 441                         if (loaded_session || !conf_launchable(conf2)) {
 442                             /* No settings for this host; use defaults */
 443                             /* (or session was already loaded with -load) */
 444                             conf_set_str(conf, CONF_host, host);
 445                             conf_set_int(conf, CONF_port, default_port);
 446                             got_host = TRUE;
 447                         } else {
 448                             conf_copy_into(conf, conf2);
 449                             loaded_session = TRUE;
 450                         }
 451                         conf_free(conf2);
 452                     }
 453
 454                     if (user) {
 455                         /* Patch in specified username. */
 456                         conf_set_str(conf, CONF_username, user);
 457                     }
 458
 459                 }
 460             } else {
 461                 char *command;
 462                 int cmdlen, cmdsize;
 463                 cmdlen = cmdsize = 0;
 464                 command = NULL;
 465
 466                 while (argc) {
 467                     while (*p) {
 468                         if (cmdlen >= cmdsize) {
 469                             cmdsize = cmdlen + 512;
 470                             command = sresize(command, cmdsize, char);
 471                         }
 472                         command[cmdlen++]=*p++;
 473                     }
 474                     if (cmdlen >= cmdsize) {
 475                         cmdsize = cmdlen + 512;
 476                         command = sresize(command, cmdsize, char);
 477                     }
 478                     command[cmdlen++]=' '; /* always add trailing space */
 479                     if (--argc) p = *++argv;
 480                 }
 481                 if (cmdlen) command[--cmdlen]='\0';
 482                                        /* change trailing blank to NUL */
 483                 conf_set_str(conf, CONF_remote_cmd, command);
 484                 conf_set_str(conf, CONF_remote_cmd2, "");
 485                 conf_set_int(conf, CONF_nopty, TRUE);  /* command => no tty */
 486
 487                 break;                 /* done with cmdline */
 488             }
 489         }
 490     }
 491
 492     if (errors)
 493         return 1;
 494
 495     if (!conf_launchable(conf) || !(got_host || loaded_session)) {
 496         usage();
 497     }
 498
 499     /*
 500      * Muck about with the hostname in various ways.
 501      */
 502     {
 503         char *hostbuf = dupstr(conf_get_str(conf, CONF_host));
 504         char *host = hostbuf;
 505         char *p, *q;
 506
 507         /*
 508          * Trim leading whitespace.
 509          */
 510         host += strspn(host, " \t");
 511
 512         /*
 513          * See if host is of the form user@host, and separate out
 514          * the username if so.
 515          */
 516         if (host[0] != '\0') {
 517             char *atsign = strrchr(host, '@');
 518             if (atsign) {
 519                 *atsign = '\0';
 520                 conf_set_str(conf, CONF_username, host);
 521                 host = atsign + 1;
 522             }
 523         }
 524
 525         /*
 526          * Trim off a colon suffix if it's there.
 527          */
 528         host[strcspn(host, ":")] = '\0';
 529
 530         /*
 531          * Remove any remaining whitespace.
 532          */
 533         p = hostbuf;
 534         q = host;
 535         while (*q) {
 536             if (*q != ' ' && *q != '\t')
 537                 *p++ = *q;
 538             q++;
 539         }
 540         *p = '\0';
 541
 542         conf_set_str(conf, CONF_host, hostbuf);
 543         sfree(hostbuf);
 544     }
 545
 546     /*
 547      * Perform command-line overrides on session configuration.
 548      */
 549     cmdline_run_saved(conf);
 550
 551     /*
 552      * Apply subsystem status.
 553      */
 554     if (use_subsystem)
 555         conf_set_int(conf, CONF_ssh_subsys, TRUE);
 556
 557     if (!*conf_get_str(conf, CONF_remote_cmd) &&
 558         !*conf_get_str(conf, CONF_remote_cmd2) &&
 559         !*conf_get_str(conf, CONF_ssh_nc_host))
 560         flags |= FLAG_INTERACTIVE;
 561
 562     /*
 563      * Select protocol. This is farmed out into a table in a
 564      * separate file to enable an ssh-free variant.
 565      */
 566     back = backend_from_proto(conf_get_int(conf, CONF_protocol));
 567     if (back == NULL) {
 568         fprintf(stderr,
 569                 "Internal fault: Unsupported protocol found\n");
 570         return 1;
 571     }
 572
 573     /*
 574      * Select port.
 575      */
 576     if (portnumber != -1)
 577         conf_set_int(conf, CONF_port, portnumber);
 578
 579     sk_init();
 580     if (p_WSAEventSelect == NULL) {
 581         fprintf(stderr, "Plink requires WinSock 2\n");
 582         return 1;
 583     }
 584
 585     logctx = log_init(NULL, conf);
 586     console_provide_logctx(logctx);
 587
 588     /*
 589      * Start up the connection.
 590      */
 591     netevent = CreateEvent(NULL, FALSE, FALSE, NULL);
 592     {
 593         const char *error;
 594         char *realhost;
 595         /* nodelay is only useful if stdin is a character device (console) */
 596         int nodelay = conf_get_int(conf, CONF_tcp_nodelay) &&
 597             (GetFileType(GetStdHandle(STD_INPUT_HANDLE)) == FILE_TYPE_CHAR);
 598
 599         error = back->init(NULL, &backhandle, conf,
 600                            conf_get_str(conf, CONF_host),
 601                            conf_get_int(conf, CONF_port),
 602                            &realhost, nodelay,
 603                            conf_get_int(conf, CONF_tcp_keepalives));
 604         if (error) {
 605             fprintf(stderr, "Unable to open connection:\n%s", error);
 606             return 1;
 607         }
 608         back->provide_logctx(backhandle, logctx);
 609         sfree(realhost);
 610     }
 611     connopen = 1;
 612
 613     inhandle = GetStdHandle(STD_INPUT_HANDLE);
 614     outhandle = GetStdHandle(STD_OUTPUT_HANDLE);
 615     errhandle = GetStdHandle(STD_ERROR_HANDLE);
 616
 617     /*
 618      * Turn off ECHO and LINE input modes. We don't care if this
 619      * call fails, because we know we aren't necessarily running in
 620      * a console.
 621      */
 622     GetConsoleMode(inhandle, &orig_console_mode);
 623     SetConsoleMode(inhandle, ENABLE_PROCESSED_INPUT);
 624
 625     /*
 626      * Pass the output handles to the handle-handling subsystem.
 627      * (The input one we leave until we're through the
 628      * authentication process.)
 629      */
 630     stdout_handle = handle_output_new(outhandle, stdouterr_sent, NULL, 0);
 631     stderr_handle = handle_output_new(errhandle, stdouterr_sent, NULL, 0);
 632
 633     main_thread_id = GetCurrentThreadId();
 634
 635     sending = FALSE;
 636
 637     now = GETTICKCOUNT();
 638
 639     while (1) {
 640         int nhandles;
 641         HANDLE *handles;
 642         int n;
 643         DWORD ticks;
 644
 645         if (!sending && back->sendok(backhandle)) {
 646             stdin_handle = handle_input_new(inhandle, stdin_gotdata, NULL,
 647                                             0);
 648             sending = TRUE;
 649         }
 650
 651         if (run_timers(now, &next)) {
 652             then = now;
 653             now = GETTICKCOUNT();
 654             if (now - then > next - then)
 655                 ticks = 0;
 656             else
 657                 ticks = next - now;
 658         } else {
 659             ticks = INFINITE;
 660         }
 661
 662         handles = handle_get_events(&nhandles);
 663         handles = sresize(handles, nhandles+1, HANDLE);
 664         handles[nhandles] = netevent;
 665         n = MsgWaitForMultipleObjects(nhandles+1, handles, FALSE, ticks,
 666                                       QS_POSTMESSAGE);
 667         if ((unsigned)(n - WAIT_OBJECT_0) < (unsigned)nhandles) {
 668             handle_got_event(handles[n - WAIT_OBJECT_0]);
 669         } else if (n == WAIT_OBJECT_0 + nhandles) {
 670             WSANETWORKEVENTS things;
 671             SOCKET socket;
 672             extern SOCKET first_socket(int *), next_socket(int *);
 673             extern int select_result(WPARAM, LPARAM);
 674             int i, socketstate;
 675
 676             /*
 677              * We must not call select_result() for any socket
 678              * until we have finished enumerating within the tree.
 679              * This is because select_result() may close the socket
 680              * and modify the tree.
 681              */
 682             /* Count the active sockets. */
 683             i = 0;
 684             for (socket = first_socket(&socketstate);
 685                  socket != INVALID_SOCKET;
 686                  socket = next_socket(&socketstate)) i++;
 687
 688             /* Expand the buffer if necessary. */
 689             if (i > sksize) {
 690                 sksize = i + 16;
 691                 sklist = sresize(sklist, sksize, SOCKET);
 692             }
 693
 694             /* Retrieve the sockets into sklist. */
 695             skcount = 0;
 696             for (socket = first_socket(&socketstate);
 697                  socket != INVALID_SOCKET;
 698                  socket = next_socket(&socketstate)) {
 699                 sklist[skcount++] = socket;
 700             }
 701
 702             /* Now we're done enumerating; go through the list. */
 703             for (i = 0; i < skcount; i++) {
 704                 WPARAM wp;
 705                 socket = sklist[i];
 706                 wp = (WPARAM) socket;
 707                 if (!p_WSAEnumNetworkEvents(socket, NULL, &things)) {
 708                     static const struct { int bit, mask; } eventtypes[] = {
 709                         {FD_CONNECT_BIT, FD_CONNECT},
 710                         {FD_READ_BIT, FD_READ},
 711                         {FD_CLOSE_BIT, FD_CLOSE},
 712                         {FD_OOB_BIT, FD_OOB},
 713                         {FD_WRITE_BIT, FD_WRITE},
 714                         {FD_ACCEPT_BIT, FD_ACCEPT},
 715                     };
 716                     int e;
 717
 718                     noise_ultralight(socket);
 719                     noise_ultralight(things.lNetworkEvents);
 720
 721                     for (e = 0; e < lenof(eventtypes); e++)
 722                         if (things.lNetworkEvents & eventtypes[e].mask) {
 723                             LPARAM lp;
 724                             int err = things.iErrorCode[eventtypes[e].bit];
 725                             lp = WSAMAKESELECTREPLY(eventtypes[e].mask, err);
 726                             connopen &= select_result(wp, lp);
 727                         }
 728                 }
 729             }
 730         } else if (n == WAIT_OBJECT_0 + nhandles + 1) {
 731             MSG msg;
 732             while (PeekMessage(&msg, INVALID_HANDLE_VALUE,
 733                                WM_AGENT_CALLBACK, WM_AGENT_CALLBACK,
 734                                PM_REMOVE)) {
 735                 struct agent_callback *c = (struct agent_callback *)msg.lParam;
 736                 c->callback(c->callback_ctx, c->data, c->len);
 737                 sfree(c);
 738             }
 739         }
 740
 741         if (n == WAIT_TIMEOUT) {
 742             now = next;
 743         } else {
 744             now = GETTICKCOUNT();
 745         }
 746
 747         sfree(handles);
 748
 749         if (sending)
 750             handle_unthrottle(stdin_handle, back->sendbuffer(backhandle));
 751
 752         if ((!connopen || !back->connected(backhandle)) &&
 753             handle_backlog(stdout_handle) + handle_backlog(stderr_handle) == 0)
 754             break;                     /* we closed the connection */
 755     }
 756     exitcode = back->exitcode(backhandle);
 757     if (exitcode < 0) {
 758         fprintf(stderr, "Remote process exit code unavailable\n");
 759         exitcode = 1;                  /* this is an error condition */
 760     }
 761     cleanup_exit(exitcode);
 762     return 0;                          /* placate compiler warning */
 763 }