File: pex-win32.c

package info (click to toggle)
gdb 8.2.1-2
  • links: PTS, VCS
  • area: main
  • in suites: bullseye, buster, sid
  • size: 223,696 kB
  • sloc: ansic: 1,936,156; asm: 341,757; exp: 146,606; makefile: 56,749; sh: 23,776; cpp: 20,830; yacc: 12,914; perl: 5,331; ada: 4,977; python: 4,617; xml: 4,176; pascal: 3,134; lisp: 1,527; cs: 879; lex: 620; f90: 479; sed: 228; awk: 140; objc: 134; fortran: 43
file content (984 lines) | stat: -rw-r--r-- 26,223 bytes parent folder | download | duplicates (11)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
/* Utilities to execute a program in a subprocess (possibly linked by pipes
   with other subprocesses), and wait for it.  Generic Win32 specialization.
   Copyright (C) 1996-2018 Free Software Foundation, Inc.

This file is part of the libiberty library.
Libiberty is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.

Libiberty is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with libiberty; see the file COPYING.LIB.  If not,
write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
Boston, MA 02110-1301, USA.  */

#include "pex-common.h"

#include <windows.h>

#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_SYS_WAIT_H
#include <sys/wait.h>
#endif

#include <assert.h>
#include <process.h>
#include <io.h>
#include <fcntl.h>
#include <signal.h>
#include <sys/stat.h>
#include <errno.h>
#include <ctype.h>

/* mingw32 headers may not define the following.  */

#ifndef _P_WAIT
#  define _P_WAIT	0
#  define _P_NOWAIT	1
#  define _P_OVERLAY	2
#  define _P_NOWAITO	3
#  define _P_DETACH	4

#  define WAIT_CHILD		0
#  define WAIT_GRANDCHILD	1
#endif

#define MINGW_NAME "Minimalist GNU for Windows"
#define MINGW_NAME_LEN (sizeof(MINGW_NAME) - 1)

extern char *stpcpy (char *dst, const char *src);

/* Ensure that the executable pathname uses Win32 backslashes. This
   is not necessary on NT, but on W9x, forward slashes causes
   failure of spawn* and exec* functions (and probably any function
   that calls CreateProcess) *iff* the executable pathname (argv[0])
   is a quoted string.  And quoting is necessary in case a pathname
   contains embedded white space.  You can't win.  */
static void
backslashify (char *s)
{
  while ((s = strchr (s, '/')) != NULL)
    *s = '\\';
  return;
}

static int pex_win32_open_read (struct pex_obj *, const char *, int);
static int pex_win32_open_write (struct pex_obj *, const char *, int, int);
static pid_t pex_win32_exec_child (struct pex_obj *, int, const char *,
				  char * const *, char * const *,
                                  int, int, int, int,
				  const char **, int *);
static int pex_win32_close (struct pex_obj *, int);
static pid_t pex_win32_wait (struct pex_obj *, pid_t, int *,
			   struct pex_time *, int, const char **, int *);
static int pex_win32_pipe (struct pex_obj *, int *, int);
static FILE *pex_win32_fdopenr (struct pex_obj *, int, int);
static FILE *pex_win32_fdopenw (struct pex_obj *, int, int);

/* The list of functions we pass to the common routines.  */

const struct pex_funcs funcs =
{
  pex_win32_open_read,
  pex_win32_open_write,
  pex_win32_exec_child,
  pex_win32_close,
  pex_win32_wait,
  pex_win32_pipe,
  pex_win32_fdopenr,
  pex_win32_fdopenw,
  NULL /* cleanup */
};

/* Return a newly initialized pex_obj structure.  */

struct pex_obj *
pex_init (int flags, const char *pname, const char *tempbase)
{
  return pex_init_common (flags, pname, tempbase, &funcs);
}

/* Open a file for reading.  */

static int
pex_win32_open_read (struct pex_obj *obj ATTRIBUTE_UNUSED, const char *name,
		     int binary)
{
  return _open (name, _O_RDONLY | (binary ? _O_BINARY : _O_TEXT));
}

/* Open a file for writing.  */

static int
pex_win32_open_write (struct pex_obj *obj ATTRIBUTE_UNUSED, const char *name,
		      int binary, int append)
{
  /* Note that we can't use O_EXCL here because gcc may have already
     created the temporary file via make_temp_file.  */
  if (append)
    return -1;
  return _open (name,
		(_O_WRONLY | _O_CREAT | _O_TRUNC
		 | (binary ? _O_BINARY : _O_TEXT)),
		_S_IREAD | _S_IWRITE);
}

/* Close a file.  */

static int
pex_win32_close (struct pex_obj *obj ATTRIBUTE_UNUSED, int fd)
{
  return _close (fd);
}

#ifdef USE_MINGW_MSYS
static const char *mingw_keys[] = {"SOFTWARE", "Microsoft", "Windows", "CurrentVersion", "Uninstall", NULL};

/* Tack the executable on the end of a (possibly slash terminated) buffer
   and convert everything to \. */
static const char *
tack_on_executable (char *buf, const char *executable)
{
  char *p = strchr (buf, '\0');
  if (p > buf && (p[-1] == '\\' || p[-1] == '/'))
    p[-1] = '\0';
  backslashify (strcat (buf, executable));
  return buf;
}

/* Walk down a registry hierarchy until the end.  Return the key. */
static HKEY
openkey (HKEY hStart, const char *keys[])
{
  HKEY hKey, hTmp;
  for (hKey = hStart; *keys; keys++)
    {
      LONG res;
      hTmp = hKey;
      res = RegOpenKey (hTmp, *keys, &hKey);

      if (hTmp != HKEY_LOCAL_MACHINE)
	RegCloseKey (hTmp);

      if (res != ERROR_SUCCESS)
	return NULL;
    }
  return hKey;
}

/* Return the "mingw root" as derived from the mingw uninstall information. */
static const char *
mingw_rootify (const char *executable)
{
  HKEY hKey, hTmp;
  DWORD maxlen;
  char *namebuf, *foundbuf;
  DWORD i;
  LONG res;

  /* Open the uninstall "directory". */
  hKey = openkey (HKEY_LOCAL_MACHINE, mingw_keys);

  /* Not found. */
  if (!hKey)
    return executable;

  /* Need to enumerate all of the keys here looking for one the most recent
     one for MinGW. */
  if (RegQueryInfoKey (hKey, NULL, NULL, NULL, NULL, &maxlen, NULL, NULL,
		       NULL, NULL, NULL, NULL) != ERROR_SUCCESS)
    {
      RegCloseKey (hKey);
      return executable;
    }
  namebuf = XNEWVEC (char, ++maxlen);
  foundbuf = XNEWVEC (char, maxlen);
  foundbuf[0] = '\0';
  if (!namebuf || !foundbuf)
    {
      RegCloseKey (hKey);
      free (namebuf);
      free (foundbuf);
      return executable;
    }

  /* Look through all of the keys for one that begins with Minimal GNU...
     Try to get the latest version by doing a string compare although that
     string never really works with version number sorting. */
  for (i = 0; RegEnumKey (hKey, i, namebuf, maxlen) == ERROR_SUCCESS; i++)
    {
      int match = strcasecmp (namebuf, MINGW_NAME);
      if (match < 0)
	continue;
      if (match > 0 && strncasecmp (namebuf, MINGW_NAME, MINGW_NAME_LEN) > 0)
	continue;
      if (strcasecmp (namebuf, foundbuf) > 0)
	strcpy (foundbuf, namebuf);
    }
  free (namebuf);

  /* If foundbuf is empty, we didn't find anything.  Punt. */
  if (!foundbuf[0])
    {
      free (foundbuf);
      RegCloseKey (hKey);
      return executable;
    }

  /* Open the key that we wanted */
  res = RegOpenKey (hKey, foundbuf, &hTmp);
  RegCloseKey (hKey);
  free (foundbuf);

  /* Don't know why this would fail, but you gotta check */
  if (res != ERROR_SUCCESS)
    return executable;

  maxlen = 0;
  /* Get the length of the value pointed to by InstallLocation */
  if (RegQueryValueEx (hTmp, "InstallLocation", 0, NULL, NULL,
		       &maxlen) != ERROR_SUCCESS || maxlen == 0)
    {
      RegCloseKey (hTmp);
      return executable;
    }

  /* Allocate space for the install location */
  foundbuf = XNEWVEC (char, maxlen + strlen (executable));
  if (!foundbuf)
    {
      free (foundbuf);
      RegCloseKey (hTmp);
    }

  /* Read the install location into the buffer */
  res = RegQueryValueEx (hTmp, "InstallLocation", 0, NULL, (LPBYTE) foundbuf,
			 &maxlen);
  RegCloseKey (hTmp);
  if (res != ERROR_SUCCESS)
    {
      free (foundbuf);
      return executable;
    }

  /* Concatenate the install location and the executable, turn all slashes
     to backslashes, and return that. */
  return tack_on_executable (foundbuf, executable);
}

/* Read the install location of msys from it's installation file and
   rootify the executable based on that. */
static const char *
msys_rootify (const char *executable)
{
  size_t bufsize = 64;
  size_t execlen = strlen (executable) + 1;
  char *buf;
  DWORD res = 0;
  for (;;)
    {
      buf = XNEWVEC (char, bufsize + execlen);
      if (!buf)
	break;
      res = GetPrivateProfileString ("InstallSettings", "InstallPath", NULL,
				     buf, bufsize, "msys.ini");
      if (!res)
	break;
      if (strlen (buf) < bufsize)
	break;
      res = 0;
      free (buf);
      bufsize *= 2;
      if (bufsize > 65536)
	{
	  buf = NULL;
	  break;
	}
    }

  if (res)
    return tack_on_executable (buf, executable);

  /* failed */
  free (buf);
  return executable;
}
#endif

/* Return the number of arguments in an argv array, not including the null
   terminating argument. */

static int
argv_to_argc (char *const *argv)
{
  char *const *i = argv;
  while (*i)
    i++;
  return i - argv;
}

/* Return a Windows command-line from ARGV.  It is the caller's
   responsibility to free the string returned.  */

static char *
argv_to_cmdline (char *const *argv)
{
  char *cmdline;
  char *p;
  size_t cmdline_len;
  int i, j, k;
  int needs_quotes;

  cmdline_len = 0;
  for (i = 0; argv[i]; i++)
    {
      /* We only quote arguments that contain spaces, \t or " characters to
	 prevent wasting 2 chars per argument of the CreateProcess 32k char
	 limit.  We need only escape embedded double-quotes and immediately
	 preceeding backslash characters.  A sequence of backslach characters
	 that is not follwed by a double quote character will not be
	 escaped.  */
      needs_quotes = 0;
      for (j = 0; argv[i][j]; j++)
	{
	  if (argv[i][j] == ' ' || argv[i][j] == '\t' || argv[i][j] == '"')
	    {
	      needs_quotes = 1;
	    }

	  if (argv[i][j] == '"')
	    {
	      /* Escape preceeding backslashes.  */
	      for (k = j - 1; k >= 0 && argv[i][k] == '\\'; k--)
		cmdline_len++;
	      /* Escape the qote character.  */
	      cmdline_len++;
	    }
	}
      if (j == 0)
	needs_quotes = 1;
      /* Trailing backslashes also need to be escaped because they will be
         followed by the terminating quote.  */
      if (needs_quotes)
        {
          for (k = j - 1; k >= 0 && argv[i][k] == '\\'; k--)
            cmdline_len++;
        }
      cmdline_len += j;
      /* for leading and trailing quotes and space */
      cmdline_len += needs_quotes * 2 + 1;
    }
  cmdline = XNEWVEC (char, cmdline_len);
  p = cmdline;
  for (i = 0; argv[i]; i++)
    {
      needs_quotes = 0;
      for (j = 0; argv[i][j]; j++)
        {
          if (argv[i][j] == ' ' || argv[i][j] == '\t' || argv[i][j] == '"')
            {
              needs_quotes = 1;
              break;
            }
        }
      if (j == 0)
	needs_quotes = 1;

      if (needs_quotes)
        {
          *p++ = '"';
        }
      for (j = 0; argv[i][j]; j++)
	{
	  if (argv[i][j] == '"')
	    {
	      for (k = j - 1; k >= 0 && argv[i][k] == '\\'; k--)
		*p++ = '\\';
	      *p++ = '\\';
	    }
	  *p++ = argv[i][j];
	}
      if (needs_quotes)
        {
          for (k = j - 1; k >= 0 && argv[i][k] == '\\'; k--)
            *p++ = '\\';
          *p++ = '"';
        }
      *p++ = ' ';
    }
  p[-1] = '\0';
  return cmdline;
}

/* We'll try the passed filename with all the known standard
   extensions, and then without extension.  We try no extension
   last so that we don't try to run some random extension-less
   file that might be hanging around.  We try both extension
   and no extension so that we don't need any fancy logic
   to determine if a file has extension.  */
static const char *const
std_suffixes[] = {
  ".com",
  ".exe",
  ".bat",
  ".cmd",
  "",
  0
};

/* Returns the full path to PROGRAM.  If SEARCH is true, look for
   PROGRAM in each directory in PATH.  */

static char *
find_executable (const char *program, BOOL search)
{
  char *full_executable;
  char *e;
  size_t fe_len;
  const char *path = 0;
  const char *const *ext;
  const char *p, *q;
  size_t proglen = strlen (program);
  int has_slash = (strchr (program, '/') || strchr (program, '\\'));
  HANDLE h;

  if (has_slash)
    search = FALSE;

  if (search)
    path = getenv ("PATH");
  if (!path)
    path = "";

  fe_len = 0;
  for (p = path; *p; p = q)
    {
      q = p;
      while (*q != ';' && *q != '\0')
	q++;
      if ((size_t)(q - p) > fe_len)
	fe_len = q - p;
      if (*q == ';')
	q++;
    }
  fe_len = fe_len + 1 + proglen + 5 /* space for extension */;
  full_executable = XNEWVEC (char, fe_len);

  p = path;
  do
    {
      q = p;
      while (*q != ';' && *q != '\0')
	q++;

      e = full_executable;
      memcpy (e, p, q - p);
      e += (q - p);
      if (q - p)
	*e++ = '\\';
      strcpy (e, program);

      if (*q == ';')
	q++;

      for (e = full_executable; *e; e++)
	if (*e == '/')
	  *e = '\\';

      /* At this point, e points to the terminating NUL character for
         full_executable.  */
      for (ext = std_suffixes; *ext; ext++)
	{
	  /* Remove any current extension.  */
	  *e = '\0';
	  /* Add the new one.  */
	  strcat (full_executable, *ext);

	  /* Attempt to open this file.  */
	  h = CreateFile (full_executable, GENERIC_READ,
			  FILE_SHARE_READ | FILE_SHARE_WRITE,
			  0, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);
	  if (h != INVALID_HANDLE_VALUE)
	    goto found;
	}
      p = q;
    }
  while (*p);
  free (full_executable);
  return 0;

 found:
  CloseHandle (h);
  return full_executable;
}

/* Low-level process creation function and helper.  */

static int
env_compare (const void *a_ptr, const void *b_ptr)
{
  const char *a;
  const char *b;
  unsigned char c1;
  unsigned char c2;

  a = *(const char **) a_ptr;
  b = *(const char **) b_ptr;

  /* a and b will be of the form: VAR=VALUE
     We compare only the variable name part here using a case-insensitive
     comparison algorithm.  It might appear that in fact strcasecmp () can
     take the place of this whole function, and indeed it could, save for
     the fact that it would fail in cases such as comparing A1=foo and
     A=bar (because 1 is less than = in the ASCII character set).
     (Environment variables containing no numbers would work in such a
     scenario.)  */

  do
    {
      c1 = (unsigned char) tolower (*a++);
      c2 = (unsigned char) tolower (*b++);

      if (c1 == '=')
        c1 = '\0';

      if (c2 == '=')
        c2 = '\0';
    }
  while (c1 == c2 && c1 != '\0');

  return c1 - c2;
}

/* Execute a Windows executable as a child process.  This will fail if the
 * target is not actually an executable, such as if it is a shell script. */

static pid_t
win32_spawn (const char *executable,
	     BOOL search,
	     char *const *argv,
             char *const *env, /* array of strings of the form: VAR=VALUE */
	     DWORD dwCreationFlags,
	     LPSTARTUPINFO si,
	     LPPROCESS_INFORMATION pi)
{
  char *full_executable;
  char *cmdline;
  char **env_copy;
  char *env_block = NULL;

  full_executable = NULL;
  cmdline = NULL;

  if (env)
    {
      int env_size;

      /* Count the number of environment bindings supplied.  */
      for (env_size = 0; env[env_size]; env_size++)
        continue;
    
      /* Assemble an environment block, if required.  This consists of
         VAR=VALUE strings juxtaposed (with one null character between each
         pair) and an additional null at the end.  */
      if (env_size > 0)
        {
          int var;
          int total_size = 1; /* 1 is for the final null.  */
          char *bufptr;
    
          /* Windows needs the members of the block to be sorted by variable
             name.  */
          env_copy = (char **) alloca (sizeof (char *) * env_size);
          memcpy (env_copy, env, sizeof (char *) * env_size);
          qsort (env_copy, env_size, sizeof (char *), env_compare);
    
          for (var = 0; var < env_size; var++)
            total_size += strlen (env[var]) + 1;
    
          env_block = XNEWVEC (char, total_size);
          bufptr = env_block;
          for (var = 0; var < env_size; var++)
            bufptr = stpcpy (bufptr, env_copy[var]) + 1;
    
          *bufptr = '\0';
        }
    }

  full_executable = find_executable (executable, search);
  if (!full_executable)
    goto error;
  cmdline = argv_to_cmdline (argv);
  if (!cmdline)
    goto error;
    
  /* Create the child process.  */  
  if (!CreateProcess (full_executable, cmdline, 
		      /*lpProcessAttributes=*/NULL,
		      /*lpThreadAttributes=*/NULL,
		      /*bInheritHandles=*/TRUE,
		      dwCreationFlags,
		      (LPVOID) env_block,
		      /*lpCurrentDirectory=*/NULL,
		      si,
		      pi))
    {
      free (env_block);

      free (full_executable);

      return (pid_t) -1;
    }

  /* Clean up.  */
  CloseHandle (pi->hThread);
  free (full_executable);
  free (env_block);

  return (pid_t) pi->hProcess;

 error:
  free (env_block);
  free (cmdline);
  free (full_executable);

  return (pid_t) -1;
}

/* Spawn a script.  This simulates the Unix script execution mechanism.
   This function is called as a fallback if win32_spawn fails. */

static pid_t
spawn_script (const char *executable, char *const *argv,
              char* const *env,
	      DWORD dwCreationFlags,
	      LPSTARTUPINFO si,
	      LPPROCESS_INFORMATION pi)
{
  pid_t pid = (pid_t) -1;
  int save_errno = errno;
  int fd = _open (executable, _O_RDONLY);

  /* Try to open script, check header format, extract interpreter path,
     and spawn script using that interpretter. */
  if (fd >= 0)
    {
      char buf[MAX_PATH + 5];
      int len = _read (fd, buf, sizeof (buf) - 1);
      _close (fd);
      if (len > 3)
	{
	  char *eol;
	  buf[len] = '\0';
	  eol = strchr (buf, '\n');
	  if (eol && strncmp (buf, "#!", 2) == 0)
	    {
            
	      /* Header format is OK. */
	      char *executable1;
              int new_argc;
              const char **avhere;

	      /* Extract interpreter path. */
	      do
		*eol = '\0';
	      while (*--eol == '\r' || *eol == ' ' || *eol == '\t');
	      for (executable1 = buf + 2; *executable1 == ' ' || *executable1 == '\t'; executable1++)
		continue;
	      backslashify (executable1);

	      /* Duplicate argv, prepending the interpreter path. */
	      new_argc = argv_to_argc (argv) + 1;
	      avhere = XNEWVEC (const char *, new_argc + 1);
	      *avhere = executable1;
	      memcpy (avhere + 1, argv, new_argc * sizeof(*argv));
	      argv = (char *const *)avhere;

	      /* Spawn the child. */
#ifndef USE_MINGW_MSYS
	      executable = strrchr (executable1, '\\') + 1;
	      if (!executable)
		executable = executable1;
	      pid = win32_spawn (executable, TRUE, argv, env,
				 dwCreationFlags, si, pi);
#else
	      if (strchr (executable1, '\\') == NULL)
		pid = win32_spawn (executable1, TRUE, argv, env,
				   dwCreationFlags, si, pi);
	      else if (executable1[0] != '\\')
		pid = win32_spawn (executable1, FALSE, argv, env,
				   dwCreationFlags, si, pi);
	      else
		{
		  const char *newex = mingw_rootify (executable1);
		  *avhere = newex;
		  pid = win32_spawn (newex, FALSE, argv, env,
				     dwCreationFlags, si, pi);
		  if (executable1 != newex)
		    free ((char *) newex);
		  if (pid == (pid_t) -1)
		    {
		      newex = msys_rootify (executable1);
		      if (newex != executable1)
			{
			  *avhere = newex;
			  pid = win32_spawn (newex, FALSE, argv, env,
					     dwCreationFlags, si, pi);
			  free ((char *) newex);
			}
		    }
		}
#endif
	      free (avhere);
	    }
	}
    }
  if (pid == (pid_t) -1)
    errno = save_errno;
  return pid;
}

/* Execute a child.  */

static pid_t
pex_win32_exec_child (struct pex_obj *obj ATTRIBUTE_UNUSED, int flags,
		      const char *executable, char * const * argv,
                      char* const* env,
		      int in, int out, int errdes,
		      int toclose ATTRIBUTE_UNUSED,
		      const char **errmsg,
		      int *err)
{
  pid_t pid;
  HANDLE stdin_handle;
  HANDLE stdout_handle;
  HANDLE stderr_handle;
  DWORD dwCreationFlags;
  OSVERSIONINFO version_info;
  STARTUPINFO si;
  PROCESS_INFORMATION pi;
  int orig_out, orig_in, orig_err;
  BOOL separate_stderr = !(flags & PEX_STDERR_TO_STDOUT);

  /* Ensure we have inheritable descriptors to pass to the child.  */
  orig_in = in;
  in = _dup (orig_in);
  
  orig_out = out;
  out = _dup (orig_out);
  
  if (separate_stderr)
    {
      orig_err = errdes;
      errdes = _dup (orig_err);
    }

  stdin_handle = INVALID_HANDLE_VALUE;
  stdout_handle = INVALID_HANDLE_VALUE;
  stderr_handle = INVALID_HANDLE_VALUE;

  stdin_handle = (HANDLE) _get_osfhandle (in);
  stdout_handle = (HANDLE) _get_osfhandle (out);
  if (separate_stderr)
    stderr_handle = (HANDLE) _get_osfhandle (errdes);
  else
    stderr_handle = stdout_handle;

  /* Determine the version of Windows we are running on.  */
  version_info.dwOSVersionInfoSize = sizeof (version_info); 
  GetVersionEx (&version_info);
  if (version_info.dwPlatformId == VER_PLATFORM_WIN32_WINDOWS)
    /* On Windows 95/98/ME the CREATE_NO_WINDOW flag is not
       supported, so we cannot avoid creating a console window.  */
    dwCreationFlags = 0;
  else
    {
      HANDLE conout_handle;

      /* Determine whether or not we have an associated console.  */
      conout_handle = CreateFile("CONOUT$", 
				 GENERIC_WRITE,
				 FILE_SHARE_WRITE,
				 /*lpSecurityAttributes=*/NULL,
				 OPEN_EXISTING,
				 FILE_ATTRIBUTE_NORMAL,
				 /*hTemplateFile=*/NULL);
      if (conout_handle == INVALID_HANDLE_VALUE)
	/* There is no console associated with this process.  Since
	   the child is a console process, the OS would normally
	   create a new console Window for the child.  Since we'll be
	   redirecting the child's standard streams, we do not need
	   the console window.  */ 
	dwCreationFlags = CREATE_NO_WINDOW;
      else 
	{
	  /* There is a console associated with the process, so the OS
	     will not create a new console.  And, if we use
	     CREATE_NO_WINDOW in this situation, the child will have
	     no associated console.  Therefore, if the child's
	     standard streams are connected to the console, the output
	     will be discarded.  */
	  CloseHandle(conout_handle);
	  dwCreationFlags = 0;
	}
    }

  /* Since the child will be a console process, it will, by default,
     connect standard input/output to its console.  However, we want
     the child to use the handles specifically designated above.  In
     addition, if there is no console (such as when we are running in
     a Cygwin X window), then we must redirect the child's
     input/output, as there is no console for the child to use.  */
  memset (&si, 0, sizeof (si));
  si.cb = sizeof (si);
  si.dwFlags = STARTF_USESTDHANDLES;
  si.hStdInput = stdin_handle;
  si.hStdOutput = stdout_handle;
  si.hStdError = stderr_handle;

  /* Create the child process.  */  
  pid = win32_spawn (executable, (flags & PEX_SEARCH) != 0,
		     argv, env, dwCreationFlags, &si, &pi);
  if (pid == (pid_t) -1)
    pid = spawn_script (executable, argv, env, dwCreationFlags,
                        &si, &pi);
  if (pid == (pid_t) -1)
    {
      *err = ENOENT;
      *errmsg = "CreateProcess";
    }

  /* If the child was created successfully, close the original file
     descriptors.  If the process creation fails, these are closed by
     pex_run_in_environment instead.  We must not close them twice as
     that seems to cause a Windows exception.  */
     
  if (pid != (pid_t) -1)
    {
      if (orig_in != STDIN_FILENO)
	_close (orig_in);
      if (orig_out != STDOUT_FILENO)
	_close (orig_out);
      if (separate_stderr
	  && orig_err != STDERR_FILENO)
	_close (orig_err);
    }

  /* Close the standard input, standard output and standard error handles
     in the parent.  */ 

  _close (in);
  _close (out);
  if (separate_stderr)
    _close (errdes);

  return pid;
}

/* Wait for a child process to complete.  MS CRTDLL doesn't return
   enough information in status to decide if the child exited due to a
   signal or not, rather it simply returns an integer with the exit
   code of the child; eg., if the child exited with an abort() call
   and didn't have a handler for SIGABRT, it simply returns with
   status == 3.  We fix the status code to conform to the usual WIF*
   macros.  Note that WIFSIGNALED will never be true under CRTDLL. */

static pid_t
pex_win32_wait (struct pex_obj *obj ATTRIBUTE_UNUSED, pid_t pid,
		int *status, struct pex_time *time, int done ATTRIBUTE_UNUSED,
		const char **errmsg, int *err)
{
  DWORD termstat;
  HANDLE h;

  if (time != NULL)
    memset (time, 0, sizeof *time);

  h = (HANDLE) pid;

  /* FIXME: If done is non-zero, we should probably try to kill the
     process.  */
  if (WaitForSingleObject (h, INFINITE) != WAIT_OBJECT_0)
    {
      CloseHandle (h);
      *err = ECHILD;
      *errmsg = "WaitForSingleObject";
      return -1;
    }

  GetExitCodeProcess (h, &termstat);
  CloseHandle (h);
 
  /* A value of 3 indicates that the child caught a signal, but not
     which one.  Since only SIGABRT, SIGFPE and SIGINT do anything, we
     report SIGABRT.  */
  if (termstat == 3)
    *status = SIGABRT;
  else
    *status = (termstat & 0xff) << 8;

  return 0;
}

/* Create a pipe.  */

static int
pex_win32_pipe (struct pex_obj *obj ATTRIBUTE_UNUSED, int *p,
		int binary)
{
  return _pipe (p, 256, (binary ? _O_BINARY : _O_TEXT) | _O_NOINHERIT);
}

/* Get a FILE pointer to read from a file descriptor.  */

static FILE *
pex_win32_fdopenr (struct pex_obj *obj ATTRIBUTE_UNUSED, int fd,
		   int binary)
{
  HANDLE h = (HANDLE) _get_osfhandle (fd);
  if (h == INVALID_HANDLE_VALUE)
    return NULL;
  if (! SetHandleInformation (h, HANDLE_FLAG_INHERIT, 0))
    return NULL;
  return fdopen (fd, binary ? "rb" : "r");
}

static FILE *
pex_win32_fdopenw (struct pex_obj *obj ATTRIBUTE_UNUSED, int fd,
		   int binary)
{
  HANDLE h = (HANDLE) _get_osfhandle (fd);
  if (h == INVALID_HANDLE_VALUE)
    return NULL;
  if (! SetHandleInformation (h, HANDLE_FLAG_INHERIT, 0))
    return NULL;
  return fdopen (fd, binary ? "wb" : "w");
}

#ifdef MAIN
#include <stdio.h>

int
main (int argc ATTRIBUTE_UNUSED, char **argv)
{
  char const *errmsg;
  int err;
  argv++;
  printf ("%ld\n", (long) pex_win32_exec_child (NULL, PEX_SEARCH, argv[0], argv, NULL, 0, 0, 1, 2, &errmsg, &err));
  exit (0);
}
#endif