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