compat/winansi.c

   1 /*
   2  * Copyright 2008 Peter Harris <git@peter.is-a-geek.org>
   3  */
   4
   5 #undef NOGDI
   6 #include "../git-compat-util.h"
   7 #include <wingdi.h>
   8 #include <winreg.h>
   9
  10 /* In this file, we actually want to use Windows' own isatty(). */
  11 #undef isatty
  12
  13 /*
  14  ANSI codes used by git: m, K
  15
  16  This file is git-specific. Therefore, this file does not attempt
  17  to implement any codes that are not used by git.
  18 */
  19
  20 static HANDLE console;
  21 static WORD plain_attr;
  22 static WORD attr;
  23 static int negative;
  24 static int non_ascii_used = 0;
  25 static HANDLE hthread, hread, hwrite;
  26 static HANDLE hconsole1, hconsole2;
  27
  28 #ifdef __MINGW32__
  29 #if !defined(__MINGW64_VERSION_MAJOR) || __MINGW64_VERSION_MAJOR < 5
  30 typedef struct _CONSOLE_FONT_INFOEX {
  31         ULONG cbSize;
  32         DWORD nFont;
  33         COORD dwFontSize;
  34         UINT FontFamily;
  35         UINT FontWeight;
  36         WCHAR FaceName[LF_FACESIZE];
  37 } CONSOLE_FONT_INFOEX, *PCONSOLE_FONT_INFOEX;
  38 #endif
  39 #endif
  40
  41 typedef BOOL (WINAPI *PGETCURRENTCONSOLEFONTEX)(HANDLE, BOOL,
  42                 PCONSOLE_FONT_INFOEX);
  43
  44 static void warn_if_raster_font(void)
  45 {
  46         DWORD fontFamily = 0;
  47         PGETCURRENTCONSOLEFONTEX pGetCurrentConsoleFontEx;
  48
  49         /* don't bother if output was ascii only */
  50         if (!non_ascii_used)
  51                 return;
  52
  53         /* GetCurrentConsoleFontEx is available since Vista */
  54         pGetCurrentConsoleFontEx = (PGETCURRENTCONSOLEFONTEX) GetProcAddress(
  55                         GetModuleHandle("kernel32.dll"),
  56                         "GetCurrentConsoleFontEx");
  57         if (pGetCurrentConsoleFontEx) {
  58                 CONSOLE_FONT_INFOEX cfi;
  59                 cfi.cbSize = sizeof(cfi);
  60                 if (pGetCurrentConsoleFontEx(console, 0, &cfi))
  61                         fontFamily = cfi.FontFamily;
  62         } else {
  63                 /* pre-Vista: check default console font in registry */
  64                 HKEY hkey;
  65                 if (ERROR_SUCCESS == RegOpenKeyExA(HKEY_CURRENT_USER, "Console",
  66                                 0, KEY_READ, &hkey)) {
  67                         DWORD size = sizeof(fontFamily);
  68                         RegQueryValueExA(hkey, "FontFamily", NULL, NULL,
  69                                         (LPVOID) &fontFamily, &size);
  70                         RegCloseKey(hkey);
  71                 }
  72         }
  73
  74         if (!(fontFamily & TMPF_TRUETYPE)) {
  75                 const wchar_t *msg = L"\nWarning: Your console font probably "
  76                         L"doesn\'t support Unicode. If you experience strange "
  77                         L"characters in the output, consider switching to a "
  78                         L"TrueType font such as Consolas!\n";
  79                 DWORD dummy;
  80                 WriteConsoleW(console, msg, wcslen(msg), &dummy, NULL);
  81         }
  82 }
  83
  84 static int is_console(int fd)
  85 {
  86         CONSOLE_SCREEN_BUFFER_INFO sbi;
  87         DWORD mode;
  88         HANDLE hcon;
  89
  90         static int initialized = 0;
  91
  92         /* get OS handle of the file descriptor */
  93         hcon = (HANDLE) _get_osfhandle(fd);
  94         if (hcon == INVALID_HANDLE_VALUE)
  95                 return 0;
  96
  97         /* check if its a device (i.e. console, printer, serial port) */
  98         if (GetFileType(hcon) != FILE_TYPE_CHAR)
  99                 return 0;
 100
 101         /* check if its a handle to a console output screen buffer */
 102         if (!fd) {
 103                 if (!GetConsoleMode(hcon, &mode))
 104                         return 0;
 105         } else if (!GetConsoleScreenBufferInfo(hcon, &sbi))
 106                 return 0;
 107
 108         /* initialize attributes */
 109         if (!initialized) {
 110                 console = hcon;
 111                 attr = plain_attr = sbi.wAttributes;
 112                 negative = 0;
 113                 initialized = 1;
 114         }
 115
 116         return 1;
 117 }
 118
 119 #define BUFFER_SIZE 4096
 120 #define MAX_PARAMS 16
 121
 122 static void write_console(unsigned char *str, size_t len)
 123 {
 124         /* only called from console_thread, so a static buffer will do */
 125         static wchar_t wbuf[2 * BUFFER_SIZE + 1];
 126         DWORD dummy;
 127
 128         /* convert utf-8 to utf-16 */
 129         int wlen = xutftowcsn(wbuf, (char*) str, ARRAY_SIZE(wbuf), len);
 130
 131         /* write directly to console */
 132         WriteConsoleW(console, wbuf, wlen, &dummy, NULL);
 133
 134         /* remember if non-ascii characters are printed */
 135         if (wlen != len)
 136                 non_ascii_used = 1;
 137 }
 138
 139 #define FOREGROUND_ALL (FOREGROUND_RED | FOREGROUND_GREEN | FOREGROUND_BLUE)
 140 #define BACKGROUND_ALL (BACKGROUND_RED | BACKGROUND_GREEN | BACKGROUND_BLUE)
 141
 142 static void set_console_attr(void)
 143 {
 144         WORD attributes = attr;
 145         if (negative) {
 146                 attributes &= ~FOREGROUND_ALL;
 147                 attributes &= ~BACKGROUND_ALL;
 148
 149                 /* This could probably use a bitmask
 150                    instead of a series of ifs */
 151                 if (attr & FOREGROUND_RED)
 152                         attributes |= BACKGROUND_RED;
 153                 if (attr & FOREGROUND_GREEN)
 154                         attributes |= BACKGROUND_GREEN;
 155                 if (attr & FOREGROUND_BLUE)
 156                         attributes |= BACKGROUND_BLUE;
 157
 158                 if (attr & BACKGROUND_RED)
 159                         attributes |= FOREGROUND_RED;
 160                 if (attr & BACKGROUND_GREEN)
 161                         attributes |= FOREGROUND_GREEN;
 162                 if (attr & BACKGROUND_BLUE)
 163                         attributes |= FOREGROUND_BLUE;
 164         }
 165         SetConsoleTextAttribute(console, attributes);
 166 }
 167
 168 static void erase_in_line(void)
 169 {
 170         CONSOLE_SCREEN_BUFFER_INFO sbi;
 171         DWORD dummy; /* Needed for Windows 7 (or Vista) regression */
 172
 173         if (!console)
 174                 return;
 175
 176         GetConsoleScreenBufferInfo(console, &sbi);
 177         FillConsoleOutputCharacterA(console, ' ',
 178                 sbi.dwSize.X - sbi.dwCursorPosition.X, sbi.dwCursorPosition,
 179                 &dummy);
 180 }
 181
 182 static void set_attr(char func, const int *params, int paramlen)
 183 {
 184         int i;
 185         switch (func) {
 186         case 'm':
 187                 for (i = 0; i < paramlen; i++) {
 188                         switch (params[i]) {
 189                         case 0: /* reset */
 190                                 attr = plain_attr;
 191                                 negative = 0;
 192                                 break;
 193                         case 1: /* bold */
 194                                 attr |= FOREGROUND_INTENSITY;
 195                                 break;
 196                         case 2:  /* faint */
 197                         case 22: /* normal */
 198                                 attr &= ~FOREGROUND_INTENSITY;
 199                                 break;
 200                         case 3:  /* italic */
 201                                 /* Unsupported */
 202                                 break;
 203                         case 4:  /* underline */
 204                         case 21: /* double underline */
 205                                 /* Wikipedia says this flag does nothing */
 206                                 /* Furthermore, mingw doesn't define this flag
 207                                 attr |= COMMON_LVB_UNDERSCORE; */
 208                                 break;
 209                         case 24: /* no underline */
 210                                 /* attr &= ~COMMON_LVB_UNDERSCORE; */
 211                                 break;
 212                         case 5:  /* slow blink */
 213                         case 6:  /* fast blink */
 214                                 /* We don't have blink, but we do have
 215                                    background intensity */
 216                                 attr |= BACKGROUND_INTENSITY;
 217                                 break;
 218                         case 25: /* no blink */
 219                                 attr &= ~BACKGROUND_INTENSITY;
 220                                 break;
 221                         case 7:  /* negative */
 222                                 negative = 1;
 223                                 break;
 224                         case 27: /* positive */
 225                                 negative = 0;
 226                                 break;
 227                         case 8:  /* conceal */
 228                         case 28: /* reveal */
 229                                 /* Unsupported */
 230                                 break;
 231                         case 30: /* Black */
 232                                 attr &= ~FOREGROUND_ALL;
 233                                 break;
 234                         case 31: /* Red */
 235                                 attr &= ~FOREGROUND_ALL;
 236                                 attr |= FOREGROUND_RED;
 237                                 break;
 238                         case 32: /* Green */
 239                                 attr &= ~FOREGROUND_ALL;
 240                                 attr |= FOREGROUND_GREEN;
 241                                 break;
 242                         case 33: /* Yellow */
 243                                 attr &= ~FOREGROUND_ALL;
 244                                 attr |= FOREGROUND_RED | FOREGROUND_GREEN;
 245                                 break;
 246                         case 34: /* Blue */
 247                                 attr &= ~FOREGROUND_ALL;
 248                                 attr |= FOREGROUND_BLUE;
 249                                 break;
 250                         case 35: /* Magenta */
 251                                 attr &= ~FOREGROUND_ALL;
 252                                 attr |= FOREGROUND_RED | FOREGROUND_BLUE;
 253                                 break;
 254                         case 36: /* Cyan */
 255                                 attr &= ~FOREGROUND_ALL;
 256                                 attr |= FOREGROUND_GREEN | FOREGROUND_BLUE;
 257                                 break;
 258                         case 37: /* White */
 259                                 attr |= FOREGROUND_RED |
 260                                         FOREGROUND_GREEN |
 261                                         FOREGROUND_BLUE;
 262                                 break;
 263                         case 38: /* Unknown */
 264                                 break;
 265                         case 39: /* reset */
 266                                 attr &= ~FOREGROUND_ALL;
 267                                 attr |= (plain_attr & FOREGROUND_ALL);
 268                                 break;
 269                         case 40: /* Black */
 270                                 attr &= ~BACKGROUND_ALL;
 271                                 break;
 272                         case 41: /* Red */
 273                                 attr &= ~BACKGROUND_ALL;
 274                                 attr |= BACKGROUND_RED;
 275                                 break;
 276                         case 42: /* Green */
 277                                 attr &= ~BACKGROUND_ALL;
 278                                 attr |= BACKGROUND_GREEN;
 279                                 break;
 280                         case 43: /* Yellow */
 281                                 attr &= ~BACKGROUND_ALL;
 282                                 attr |= BACKGROUND_RED | BACKGROUND_GREEN;
 283                                 break;
 284                         case 44: /* Blue */
 285                                 attr &= ~BACKGROUND_ALL;
 286                                 attr |= BACKGROUND_BLUE;
 287                                 break;
 288                         case 45: /* Magenta */
 289                                 attr &= ~BACKGROUND_ALL;
 290                                 attr |= BACKGROUND_RED | BACKGROUND_BLUE;
 291                                 break;
 292                         case 46: /* Cyan */
 293                                 attr &= ~BACKGROUND_ALL;
 294                                 attr |= BACKGROUND_GREEN | BACKGROUND_BLUE;
 295                                 break;
 296                         case 47: /* White */
 297                                 attr |= BACKGROUND_RED |
 298                                         BACKGROUND_GREEN |
 299                                         BACKGROUND_BLUE;
 300                                 break;
 301                         case 48: /* Unknown */
 302                                 break;
 303                         case 49: /* reset */
 304                                 attr &= ~BACKGROUND_ALL;
 305                                 attr |= (plain_attr & BACKGROUND_ALL);
 306                                 break;
 307                         default:
 308                                 /* Unsupported code */
 309                                 break;
 310                         }
 311                 }
 312                 set_console_attr();
 313                 break;
 314         case 'K':
 315                 erase_in_line();
 316                 break;
 317         default:
 318                 /* Unsupported code */
 319                 break;
 320         }
 321 }
 322
 323 enum {
 324         TEXT = 0, ESCAPE = 033, BRACKET = '['
 325 };
 326
 327 static DWORD WINAPI console_thread(LPVOID unused)
 328 {
 329         unsigned char buffer[BUFFER_SIZE];
 330         DWORD bytes;
 331         int start, end = 0, c, parampos = 0, state = TEXT;
 332         int params[MAX_PARAMS];
 333
 334         while (1) {
 335                 /* read next chunk of bytes from the pipe */
 336                 if (!ReadFile(hread, buffer + end, BUFFER_SIZE - end, &bytes,
 337                                 NULL)) {
 338                         /* exit if pipe has been closed or disconnected */
 339                         if (GetLastError() == ERROR_PIPE_NOT_CONNECTED ||
 340                                         GetLastError() == ERROR_BROKEN_PIPE)
 341                                 break;
 342                         /* ignore other errors */
 343                         continue;
 344                 }
 345
 346                 /* scan the bytes and handle ANSI control codes */
 347                 bytes += end;
 348                 start = end = 0;
 349                 while (end < bytes) {
 350                         c = buffer[end++];
 351                         switch (state) {
 352                         case TEXT:
 353                                 if (c == ESCAPE) {
 354                                         /* print text seen so far */
 355                                         if (end - 1 > start)
 356                                                 write_console(buffer + start,
 357                                                         end - 1 - start);
 358
 359                                         /* then start parsing escape sequence */
 360                                         start = end - 1;
 361                                         memset(params, 0, sizeof(params));
 362                                         parampos = 0;
 363                                         state = ESCAPE;
 364                                 }
 365                                 break;
 366
 367                         case ESCAPE:
 368                                 /* continue if "\033[", otherwise bail out */
 369                                 state = (c == BRACKET) ? BRACKET : TEXT;
 370                                 break;
 371
 372                         case BRACKET:
 373                                 /* parse [0-9;]* into array of parameters */
 374                                 if (c >= '0' && c <= '9') {
 375                                         params[parampos] *= 10;
 376                                         params[parampos] += c - '0';
 377                                 } else if (c == ';') {
 378                                         /*
 379                                          * next parameter, bail out if out of
 380                                          * bounds
 381                                          */
 382                                         parampos++;
 383                                         if (parampos >= MAX_PARAMS)
 384                                                 state = TEXT;
 385                                 } else {
 386                                         /*
 387                                          * end of escape sequence, change
 388                                          * console attributes
 389                                          */
 390                                         set_attr(c, params, parampos + 1);
 391                                         start = end;
 392                                         state = TEXT;
 393                                 }
 394                                 break;
 395                         }
 396                 }
 397
 398                 /* print remaining text unless parsing an escape sequence */
 399                 if (state == TEXT && end > start) {
 400                         /* check for incomplete UTF-8 sequences and fix end */
 401                         if (buffer[end - 1] >= 0x80) {
 402                                 if (buffer[end -1] >= 0xc0)
 403                                         end--;
 404                                 else if (end - 1 > start &&
 405                                                 buffer[end - 2] >= 0xe0)
 406                                         end -= 2;
 407                                 else if (end - 2 > start &&
 408                                                 buffer[end - 3] >= 0xf0)
 409                                         end -= 3;
 410                         }
 411
 412                         /* print remaining complete UTF-8 sequences */
 413                         if (end > start)
 414                                 write_console(buffer + start, end - start);
 415
 416                         /* move remaining bytes to the front */
 417                         if (end < bytes)
 418                                 memmove(buffer, buffer + end, bytes - end);
 419                         end = bytes - end;
 420                 } else {
 421                         /* all data has been consumed, mark buffer empty */
 422                         end = 0;
 423                 }
 424         }
 425
 426         /* check if the console font supports unicode */
 427         warn_if_raster_font();
 428
 429         CloseHandle(hread);
 430         return 0;
 431 }
 432
 433 static void winansi_exit(void)
 434 {
 435         /* flush all streams */
 436         _flushall();
 437
 438         /* signal console thread to exit */
 439         FlushFileBuffers(hwrite);
 440         DisconnectNamedPipe(hwrite);
 441
 442         /* wait for console thread to copy remaining data */
 443         WaitForSingleObject(hthread, INFINITE);
 444
 445         /* cleanup handles... */
 446         CloseHandle(hwrite);
 447         CloseHandle(hthread);
 448 }
 449
 450 static void die_lasterr(const char *fmt, ...)
 451 {
 452         va_list params;
 453         va_start(params, fmt);
 454         errno = err_win_to_posix(GetLastError());
 455         die_errno(fmt, params);
 456         va_end(params);
 457 }
 458
 459 static HANDLE duplicate_handle(HANDLE hnd)
 460 {
 461         HANDLE hresult, hproc = GetCurrentProcess();
 462         if (!DuplicateHandle(hproc, hnd, hproc, &hresult, 0, TRUE,
 463                         DUPLICATE_SAME_ACCESS))
 464                 die_lasterr("DuplicateHandle(%li) failed",
 465                         (long) (intptr_t) hnd);
 466         return hresult;
 467 }
 468
 469
 470 /*
 471  * Make MSVCRT's internal file descriptor control structure accessible
 472  * so that we can tweak OS handles and flags directly (we need MSVCRT
 473  * to treat our pipe handle as if it were a console).
 474  *
 475  * We assume that the ioinfo structure (exposed by MSVCRT.dll via
 476  * __pioinfo) starts with the OS handle and the flags. The exact size
 477  * varies between MSVCRT versions, so we try different sizes until
 478  * toggling the FDEV bit of _pioinfo(1)->osflags is reflected in
 479  * isatty(1).
 480  */
 481 typedef struct {
 482         HANDLE osfhnd;
 483         char osflags;
 484 } ioinfo;
 485
 486 extern __declspec(dllimport) ioinfo *__pioinfo[];
 487
 488 static size_t sizeof_ioinfo = 0;
 489
 490 #define IOINFO_L2E 5
 491 #define IOINFO_ARRAY_ELTS (1 << IOINFO_L2E)
 492
 493 #define FPIPE 0x08
 494 #define FDEV  0x40
 495
 496 static inline ioinfo* _pioinfo(int fd)
 497 {
 498         return (ioinfo*)((char*)__pioinfo[fd >> IOINFO_L2E] +
 499                         (fd & (IOINFO_ARRAY_ELTS - 1)) * sizeof_ioinfo);
 500 }
 501
 502 static int init_sizeof_ioinfo(void)
 503 {
 504         int istty, wastty;
 505         /* don't init twice */
 506         if (sizeof_ioinfo)
 507                 return sizeof_ioinfo >= 256;
 508
 509         sizeof_ioinfo = sizeof(ioinfo);
 510         wastty = isatty(1);
 511         while (sizeof_ioinfo < 256) {
 512                 /* toggle FDEV flag, check isatty, then toggle back */
 513                 _pioinfo(1)->osflags ^= FDEV;
 514                 istty = isatty(1);
 515                 _pioinfo(1)->osflags ^= FDEV;
 516                 /* return if we found the correct size */
 517                 if (istty != wastty)
 518                         return 0;
 519                 sizeof_ioinfo += sizeof(void*);
 520         }
 521         error("Tweaking file descriptors doesn't work with this MSVCRT.dll");
 522         return 1;
 523 }
 524
 525 static HANDLE swap_osfhnd(int fd, HANDLE new_handle)
 526 {
 527         ioinfo *pioinfo;
 528         HANDLE old_handle;
 529
 530         /* init ioinfo size if we haven't done so */
 531         if (init_sizeof_ioinfo())
 532                 return INVALID_HANDLE_VALUE;
 533
 534         /* get ioinfo pointer and change the handles */
 535         pioinfo = _pioinfo(fd);
 536         old_handle = pioinfo->osfhnd;
 537         pioinfo->osfhnd = new_handle;
 538         return old_handle;
 539 }
 540
 541 #ifdef DETECT_MSYS_TTY
 542
 543 #include <winternl.h>
 544 #include <ntstatus.h>
 545
 546 static void detect_msys_tty(int fd)
 547 {
 548         ULONG result;
 549         BYTE buffer[1024];
 550         POBJECT_NAME_INFORMATION nameinfo = (POBJECT_NAME_INFORMATION) buffer;
 551         PWSTR name;
 552
 553         /* check if fd is a pipe */
 554         HANDLE h = (HANDLE) _get_osfhandle(fd);
 555         if (GetFileType(h) != FILE_TYPE_PIPE)
 556                 return;
 557
 558         /* get pipe name */
 559         if (!NT_SUCCESS(NtQueryObject(h, ObjectNameInformation,
 560                         buffer, sizeof(buffer) - 2, &result)))
 561                 return;
 562         name = nameinfo->Name.Buffer;
 563         name[nameinfo->Name.Length] = 0;
 564
 565         /*
 566          * Check if this could be a MSYS2 pty pipe ('msys-XXXX-ptyN-XX')
 567          * or a cygwin pty pipe ('cygwin-XXXX-ptyN-XX')
 568          */
 569         if ((!wcsstr(name, L"msys-") && !wcsstr(name, L"cygwin-")) ||
 570                         !wcsstr(name, L"-pty"))
 571                 return;
 572
 573         /* init ioinfo size if we haven't done so */
 574         if (init_sizeof_ioinfo())
 575                 return;
 576
 577         /* set FDEV flag, reset FPIPE flag */
 578         _pioinfo(fd)->osflags &= ~FPIPE;
 579         _pioinfo(fd)->osflags |= FDEV;
 580 }
 581
 582 #endif
 583
 584 int winansi_isatty(int fd)
 585 {
 586         int res = isatty(fd);
 587
 588         if (res) {
 589                 /*
 590                  * Make sure that /dev/null is not fooling Git into believing
 591                  * that we are connected to a terminal, as "_isatty() returns a
 592                  * nonzero value if the descriptor is associated with a
 593                  * character device."; for more information, see
 594                  *
 595                  * https://msdn.microsoft.com/en-us/library/f4s0ddew.aspx
 596                  */
 597                 HANDLE handle = (HANDLE)_get_osfhandle(fd);
 598                 if (fd == STDIN_FILENO) {
 599                         DWORD dummy;
 600
 601                         if (!GetConsoleMode(handle, &dummy))
 602                                 res = 0;
 603                 } else if (fd == STDOUT_FILENO || fd == STDERR_FILENO) {
 604                         CONSOLE_SCREEN_BUFFER_INFO dummy;
 605
 606                         if (!GetConsoleScreenBufferInfo(handle, &dummy))
 607                                 res = 0;
 608                 }
 609         }
 610
 611         return res;
 612 }
 613
 614 void winansi_init(void)
 615 {
 616         int con1, con2;
 617         char name[32];
 618
 619         /* check if either stdout or stderr is a console output screen buffer */
 620         con1 = is_console(1);
 621         con2 = is_console(2);
 622         if (!con1 && !con2) {
 623 #ifdef DETECT_MSYS_TTY
 624                 /* check if stdin / stdout / stderr are MSYS2 pty pipes */
 625                 detect_msys_tty(0);
 626                 detect_msys_tty(1);
 627                 detect_msys_tty(2);
 628 #endif
 629                 return;
 630         }
 631
 632         /* create a named pipe to communicate with the console thread */
 633         xsnprintf(name, sizeof(name), "\\\\.\\pipe\\winansi%lu", GetCurrentProcessId());
 634         hwrite = CreateNamedPipe(name, PIPE_ACCESS_OUTBOUND,
 635                 PIPE_TYPE_BYTE | PIPE_WAIT, 1, BUFFER_SIZE, 0, 0, NULL);
 636         if (hwrite == INVALID_HANDLE_VALUE)
 637                 die_lasterr("CreateNamedPipe failed");
 638
 639         hread = CreateFile(name, GENERIC_READ, 0, NULL, OPEN_EXISTING, 0, NULL);
 640         if (hread == INVALID_HANDLE_VALUE)
 641                 die_lasterr("CreateFile for named pipe failed");
 642
 643         /* start console spool thread on the pipe's read end */
 644         hthread = CreateThread(NULL, 0, console_thread, NULL, 0, NULL);
 645         if (hthread == INVALID_HANDLE_VALUE)
 646                 die_lasterr("CreateThread(console_thread) failed");
 647
 648         /* schedule cleanup routine */
 649         if (atexit(winansi_exit))
 650                 die_errno("atexit(winansi_exit) failed");
 651
 652         /* redirect stdout / stderr to the pipe */
 653         if (con1)
 654                 hconsole1 = swap_osfhnd(1, duplicate_handle(hwrite));
 655         if (con2)
 656                 hconsole2 = swap_osfhnd(2, duplicate_handle(hwrite));
 657 }
 658
 659 /*
 660  * Returns the real console handle if stdout / stderr is a pipe redirecting
 661  * to the console. Allows spawn / exec to pass the console to the next process.
 662  */
 663 HANDLE winansi_get_osfhandle(int fd)
 664 {
 665         HANDLE hnd = (HANDLE) _get_osfhandle(fd);
 666         if (isatty(fd) && GetFileType(hnd) == FILE_TYPE_PIPE) {
 667                 if (fd == 1 && hconsole1)
 668                         return hconsole1;
 669                 else if (fd == 2 && hconsole2)
 670                         return hconsole2;
 671         }
 672         return hnd;
 673 }