summaryrefslogtreecommitdiffstats
path: root/common/exechelp-w32.c
blob: ed026e2ba0683e7aa31d504ca88fe7546f5f1405 (plain)
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
/* exechelp-w32.c - Fork and exec helpers for W32.
 * Copyright (C) 2004, 2007, 2008, 2009,
 *               2010 Free Software Foundation, Inc.
 *
 * This file is part of GnuPG.
 *
 * GnuPG is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * GnuPG 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see <http://www.gnu.org/licenses/>.
 */

#include <config.h>

#if !defined(HAVE_W32_SYSTEM) || defined (HAVE_W32CE_SYSTEM)
#error This code is only used on W32.
#endif

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <assert.h>
#ifdef HAVE_SIGNAL_H
# include <signal.h>
#endif
#include <unistd.h> 
#include <fcntl.h>

#ifdef WITHOUT_GNU_PTH /* Give the Makefile a chance to build without Pth.  */
#undef HAVE_PTH
#undef USE_GNU_PTH
#endif

#ifdef USE_GNU_PTH      
#include <pth.h>
#endif

#ifdef HAVE_STAT
# include <sys/stat.h>
#endif


#include "util.h"
#include "i18n.h"
#include "sysutils.h"
#include "exechelp.h"

/* Define to 1 do enable debugging.  */
#define DEBUG_W32_SPAWN 1


/* It seems Vista doesn't grok X_OK and so fails access() tests.
   Previous versions interpreted X_OK as F_OK anyway, so we'll just
   use F_OK directly. */
#undef X_OK
#define X_OK F_OK

/* We assume that a HANDLE can be represented by an int which should
   be true for all i386 systems (HANDLE is defined as void *) and
   these are the only systems for which Windows is available.  Further
   we assume that -1 denotes an invalid handle.  */
# define fd_to_handle(a)  ((HANDLE)(a))
# define handle_to_fd(a)  ((int)(a))
# define pid_to_handle(a) ((HANDLE)(a))
# define handle_to_pid(a) ((int)(a))


/* Return the maximum number of currently allowed open file
   descriptors.  Only useful on POSIX systems but returns a value on
   other systems too.  */
int
get_max_fds (void)
{
  int max_fds = -1;

#ifdef OPEN_MAX
  if (max_fds == -1)
    max_fds = OPEN_MAX;
#endif

  if (max_fds == -1)
    max_fds = 256;  /* Arbitrary limit.  */

  return max_fds;
}


/* Close all file descriptors starting with descriptor FIRST.  If
   EXCEPT is not NULL, it is expected to be a list of file descriptors
   which shall not be closed.  This list shall be sorted in ascending
   order with the end marked by -1.  */
void
close_all_fds (int first, int *except)
{
  int max_fd = get_max_fds ();
  int fd, i, except_start;

  if (except)
    {
      except_start = 0;
      for (fd=first; fd < max_fd; fd++)
        {
          for (i=except_start; except[i] != -1; i++)
            {
              if (except[i] == fd)
                {
                  /* If we found the descriptor in the exception list
                     we can start the next compare run at the next
                     index because the exception list is ordered.  */
                except_start = i + 1;
                break;
                }
            }
          if (except[i] == -1)
            close (fd);
        }
    }
  else
    {
      for (fd=first; fd < max_fd; fd++)
        close (fd);
    }

  gpg_err_set_errno (0);
}


/* Returns an array with all currently open file descriptors.  The end
   of the array is marked by -1.  The caller needs to release this
   array using the *standard free* and not with xfree.  This allow the
   use of this fucntion right at startup even before libgcrypt has
   been initialized.  Returns NULL on error and sets ERRNO
   accordingly.  */
int *
get_all_open_fds (void)
{
  int *array;
  size_t narray;
  int fd, max_fd, idx;
#ifndef HAVE_STAT
  array = calloc (1, sizeof *array);
  if (array)
    array[0] = -1;
#else /*HAVE_STAT*/
  struct stat statbuf;

  max_fd = get_max_fds ();
  narray = 32;  /* If you change this change also t-exechelp.c.  */
  array = calloc (narray, sizeof *array);
  if (!array)
    return NULL;
  
  /* Note:  The list we return is ordered.  */
  for (idx=0, fd=0; fd < max_fd; fd++)
    if (!(fstat (fd, &statbuf) == -1 && errno == EBADF))
      {
        if (idx+1 >= narray)
          {
            int *tmp;

            narray += (narray < 256)? 32:256;
            tmp = realloc (array, narray * sizeof *array);
            if (!tmp)
              {
                free (array);
                return NULL;
              }
            array = tmp;
          }
        array[idx++] = fd;
      }
  array[idx] = -1;
#endif /*HAVE_STAT*/
  return array;
}


/* Helper function to build_w32_commandline. */
static char *
build_w32_commandline_copy (char *buffer, const char *string)
{
  char *p = buffer;
  const char *s;

  if (!*string) /* Empty string. */
    p = stpcpy (p, "\"\"");
  else if (strpbrk (string, " \t\n\v\f\""))
    {
      /* Need to do some kind of quoting.  */
      p = stpcpy (p, "\"");
      for (s=string; *s; s++)
        {
          *p++ = *s;
          if (*s == '\"')
            *p++ = *s;
        }
      *p++ = '\"';
      *p = 0;
    }
  else
    p = stpcpy (p, string);

  return p;
}

/* Build a command line for use with W32's CreateProcess.  On success
   CMDLINE gets the address of a newly allocated string.  */
static gpg_error_t
build_w32_commandline (const char *pgmname, const char * const *argv, 
                       char **cmdline)
{
  int i, n;
  const char *s;
  char *buf, *p;

  *cmdline = NULL;
  n = 0;
  s = pgmname;
  n += strlen (s) + 1 + 2;  /* (1 space, 2 quoting */
  for (; *s; s++)
    if (*s == '\"')
      n++;  /* Need to double inner quotes.  */
  for (i=0; (s=argv[i]); i++)
    {
      n += strlen (s) + 1 + 2;  /* (1 space, 2 quoting */
      for (; *s; s++)
        if (*s == '\"')
          n++;  /* Need to double inner quotes.  */
    }
  n++;

  buf = p = xtrymalloc (n);
  if (!buf)
    return gpg_error_from_syserror ();

  p = build_w32_commandline_copy (p, pgmname);
  for (i=0; argv[i]; i++) 
    {
      *p++ = ' ';
      p = build_w32_commandline_copy (p, argv[i]);
    }

  *cmdline= buf;
  return 0;
}


/* Create pipe where one end is inheritable: With an INHERIT_IDX of 0
   the read end is inheritable, with 1 the write end is inheritable.  */
static int
create_inheritable_pipe (int filedes[2], int inherit_idx)
{
  HANDLE r, w, h;
  SECURITY_ATTRIBUTES sec_attr;

  memset (&sec_attr, 0, sizeof sec_attr );
  sec_attr.nLength = sizeof sec_attr;
  sec_attr.bInheritHandle = FALSE;
    
  if (!CreatePipe (&r, &w, &sec_attr, 0))
    return -1;

  if (!DuplicateHandle (GetCurrentProcess(), inherit_idx? w : r,
                        GetCurrentProcess(), &h, 0,
                        TRUE, DUPLICATE_SAME_ACCESS ))
    {
      log_error ("DuplicateHandle failed: %s\n", w32_strerror (-1));
      CloseHandle (r);
      CloseHandle (w);
      return -1;
    }

  if (inherit_idx)
    {
      CloseHandle (w);
      w = h;
    }
  else
    {
      CloseHandle (r);
      r = h;
    }

  filedes[0] = handle_to_fd (r);
  filedes[1] = handle_to_fd (w);
  return 0;
}


static HANDLE
w32_open_null (int for_write)
{
  HANDLE hfile;

  hfile = CreateFileW (L"nul",
                       for_write? GENERIC_WRITE : GENERIC_READ,
                       FILE_SHARE_READ | FILE_SHARE_WRITE,
                       NULL, OPEN_EXISTING, 0, NULL);
  if (hfile == INVALID_HANDLE_VALUE)
    log_debug ("can't open `nul': %s\n", w32_strerror (-1));
  return hfile;
}


static gpg_error_t
do_create_pipe (int filedes[2], int inherit_idx)
{
  gpg_error_t err = 0;
  int fds[2];

  filedes[0] = filedes[1] = -1;
  err = gpg_error (GPG_ERR_GENERAL);
  if (!create_inheritable_pipe (fds, inherit_idx))
    {
      filedes[0] = _open_osfhandle (fds[0], 0);
      if (filedes[0] == -1)
        {
          log_error ("failed to translate osfhandle %p\n", (void*)fds[0]);
          CloseHandle (fd_to_handle (fds[1]));
        }
      else 
        {
          filedes[1] = _open_osfhandle (fds[1], 1);
          if (filedes[1] == -1)
            {
              log_error ("failed to translate osfhandle %p\n", (void*)fds[1]);
              close (filedes[0]);
              filedes[0] = -1;
              CloseHandle (fd_to_handle (fds[1]));
            }
          else
            err = 0;
        }
    }
  return err;
}

/* Portable function to create a pipe.  Under Windows the write end is
   inheritable.  */
gpg_error_t
gnupg_create_inbound_pipe (int filedes[2])
{
  return do_create_pipe (filedes, 1);
}


/* Portable function to create a pipe.  Under Windows the read end is
   inheritable.  */
gpg_error_t
gnupg_create_outbound_pipe (int filedes[2])
{
  return do_create_pipe (filedes, 0);
}


/* Fork and exec the PGMNAME, see exechelp.h for details.  */
gpg_error_t
gnupg_spawn_process (const char *pgmname, const char *argv[],
                     estream_t infile, estream_t outfile,
                     void (*preexec)(void), unsigned int flags,
                     estream_t *statusfile, pid_t *pid)
{
  gpg_error_t err;
  SECURITY_ATTRIBUTES sec_attr;
  PROCESS_INFORMATION pi = 
    {
      NULL,      /* Returns process handle.  */
      0,         /* Returns primary thread handle.  */
      0,         /* Returns pid.  */
      0          /* Returns tid.  */
    };
  STARTUPINFO si;
  int cr_flags;
  char *cmdline;
  int fd, fdout, rp[2];

  (void)preexec;

  /* Setup return values.  */
  *statusfile = NULL;
  *pid = (pid_t)(-1);
  es_fflush (infile);
  es_rewind (infile);
  fd = _get_osfhandle (es_fileno (infile));
  fdout = _get_osfhandle (es_fileno (outfile));
  if (fd == -1 || fdout == -1)
    log_fatal ("no file descriptor for file passed to gnupg_spawn_process\n");

  /* Prepare security attributes.  */
  memset (&sec_attr, 0, sizeof sec_attr );
  sec_attr.nLength = sizeof sec_attr;
  sec_attr.bInheritHandle = FALSE;
  
  /* Build the command line.  */
  err = build_w32_commandline (pgmname, argv, &cmdline);
  if (err)
    return err; 

  /* Create a pipe.  */
  if (create_inheritable_pipe (rp, 1))
    {
      err = gpg_error (GPG_ERR_GENERAL);
      log_error (_("error creating a pipe: %s\n"), gpg_strerror (err));
      xfree (cmdline);
      return err;
    }
  
  /* Start the process.  Note that we can't run the PREEXEC function
     because this would change our own environment. */
  memset (&si, 0, sizeof si);
  si.cb = sizeof (si);
  si.dwFlags = STARTF_USESTDHANDLES | STARTF_USESHOWWINDOW;
  si.wShowWindow = DEBUG_W32_SPAWN? SW_SHOW : SW_MINIMIZE;
  si.hStdInput  = fd_to_handle (fd);
  si.hStdOutput = fd_to_handle (fdout);
  si.hStdError  = fd_to_handle (rp[1]);

  cr_flags = (CREATE_DEFAULT_ERROR_MODE
              | ((flags & 128)? DETACHED_PROCESS : 0)
              | GetPriorityClass (GetCurrentProcess ())
              | CREATE_SUSPENDED); 
/*   log_debug ("CreateProcess, path=`%s' cmdline=`%s'\n", pgmname, cmdline); */
  if (!CreateProcess (pgmname,       /* Program to start.  */
                      cmdline,       /* Command line arguments.  */
                      &sec_attr,     /* Process security attributes.  */
                      &sec_attr,     /* Thread security attributes.  */
                      TRUE,          /* Inherit handles.  */
                      cr_flags,      /* Creation flags.  */
                      NULL,          /* Environment.  */
                      NULL,          /* Use current drive/directory.  */
                      &si,           /* Startup information. */
                      &pi            /* Returns process information.  */
                      ))
    {
      log_error ("CreateProcess failed: %s\n", w32_strerror (-1));
      xfree (cmdline);
      CloseHandle (fd_to_handle (rp[0]));
      CloseHandle (fd_to_handle (rp[1]));
      return gpg_error (GPG_ERR_GENERAL);
    }
  xfree (cmdline);
  cmdline = NULL;

  /* Close the other end of the pipe.  */
  CloseHandle (fd_to_handle (rp[1]));
  
/*   log_debug ("CreateProcess ready: hProcess=%p hThread=%p" */
/*              " dwProcessID=%d dwThreadId=%d\n", */
/*              pi.hProcess, pi.hThread, */
/*              (int) pi.dwProcessId, (int) pi.dwThreadId); */
  
  /* Fixme: For unknown reasons AllowSetForegroundWindow returns an
     invalid argument error if we pass the correct processID to
     it.  As a workaround we use -1 (ASFW_ANY).  */
  if ( (flags & 64) )
    gnupg_allow_set_foregound_window ((pid_t)(-1)/*pi.dwProcessId*/);

  /* Process has been created suspended; resume it now. */
  ResumeThread (pi.hThread);
  CloseHandle (pi.hThread); 

  {
    int x;

    x = _open_osfhandle (rp[0], 0);
    if (x == -1)
      log_error ("failed to translate osfhandle %p\n", (void*)rp[0] );
    else 
      *statusfile = es_fdopen (x, "r");
  }
  if (!*statusfile)
    {
      err = gpg_error_from_syserror ();
      log_error (_("can't fdopen pipe for reading: %s\n"), gpg_strerror (err));
      CloseHandle (pi.hProcess);
      return err;
    }

  *pid = handle_to_pid (pi.hProcess);
  return 0;

}



/* Simplified version of gnupg_spawn_process.  This function forks and
   then execs PGMNAME, while connecting INFD to stdin, OUTFD to stdout
   and ERRFD to stderr (any of them may be -1 to connect them to
   /dev/null).  The arguments for the process are expected in the NULL
   terminated array ARGV.  The program name itself should not be
   included there.  Calling gnupg_wait_process is required.

   Returns 0 on success or an error code. */
gpg_error_t
gnupg_spawn_process_fd (const char *pgmname, const char *argv[],
                        int infd, int outfd, int errfd, pid_t *pid)
{
  gpg_error_t err;
  SECURITY_ATTRIBUTES sec_attr;
  PROCESS_INFORMATION pi = { NULL, 0, 0, 0 };
  STARTUPINFO si;
  char *cmdline;
  int i;
  HANDLE stdhd[3];

  /* Setup return values.  */
  *pid = (pid_t)(-1);

  /* Prepare security attributes.  */
  memset (&sec_attr, 0, sizeof sec_attr );
  sec_attr.nLength = sizeof sec_attr;
  sec_attr.bInheritHandle = FALSE;
  
  /* Build the command line.  */
  err = build_w32_commandline (pgmname, argv, &cmdline);
  if (err)
    return err; 

  memset (&si, 0, sizeof si);
  si.cb = sizeof (si);
  si.dwFlags = STARTF_USESTDHANDLES | STARTF_USESHOWWINDOW;
  si.wShowWindow = DEBUG_W32_SPAWN? SW_SHOW : SW_MINIMIZE;
  stdhd[0] = infd  == -1? w32_open_null (0) : INVALID_HANDLE_VALUE;
  stdhd[1] = outfd == -1? w32_open_null (1) : INVALID_HANDLE_VALUE;
  stdhd[2] = errfd == -1? w32_open_null (1) : INVALID_HANDLE_VALUE;
  si.hStdInput  = infd  == -1? stdhd[0] : (void*)_get_osfhandle (infd);
  si.hStdOutput = outfd == -1? stdhd[1] : (void*)_get_osfhandle (outfd);
  si.hStdError  = errfd == -1? stdhd[2] : (void*)_get_osfhandle (errfd);

/*   log_debug ("CreateProcess, path=`%s' cmdline=`%s'\n", pgmname, cmdline); */
  if (!CreateProcess (pgmname,       /* Program to start.  */
                      cmdline,       /* Command line arguments.  */
                      &sec_attr,     /* Process security attributes.  */
                      &sec_attr,     /* Thread security attributes.  */
                      TRUE,          /* Inherit handles.  */
                      (CREATE_DEFAULT_ERROR_MODE
                       | GetPriorityClass (GetCurrentProcess ())
                       | CREATE_SUSPENDED | DETACHED_PROCESS),
                      NULL,          /* Environment.  */
                      NULL,          /* Use current drive/directory.  */
                      &si,           /* Startup information. */
                      &pi            /* Returns process information.  */
                      ))
    {
      log_error ("CreateProcess failed: %s\n", w32_strerror (-1));
      err = gpg_error (GPG_ERR_GENERAL);
    }
  else
    err = 0;
  xfree (cmdline);
  for (i=0; i < 3; i++)
    if (stdhd[i] != INVALID_HANDLE_VALUE)
      CloseHandle (stdhd[i]);
  if (err)
    return err;

/*   log_debug ("CreateProcess ready: hProcess=%p hThread=%p" */
/*              " dwProcessID=%d dwThreadId=%d\n", */
/*              pi.hProcess, pi.hThread, */
/*              (int) pi.dwProcessId, (int) pi.dwThreadId); */

  /* Process has been created suspended; resume it now. */
  ResumeThread (pi.hThread);
  CloseHandle (pi.hThread); 

  *pid = handle_to_pid (pi.hProcess);
  return 0;

}


/* Wait for the process identified by PID to terminate. PGMNAME should
   be the same as supplied to the spawn function and is only used for
   diagnostics. Returns 0 if the process succeeded, GPG_ERR_GENERAL
   for any failures of the spawned program or other error codes.  If
   EXITCODE is not NULL the exit code of the process is stored at this
   address or -1 if it could not be retrieved. */
gpg_error_t
gnupg_wait_process (const char *pgmname, pid_t pid, int *exitcode)
{
  gpg_err_code_t ec;
  HANDLE proc = fd_to_handle (pid);
  int code;
  DWORD exc;

  if (exitcode)
    *exitcode = -1;

  if (pid == (pid_t)(-1))
    return gpg_error (GPG_ERR_INV_VALUE);

  /* FIXME: We should do a pth_waitpid here.  However this has not yet
     been implemented.  A special W32 pth system call would even be
     better.  */
  code = WaitForSingleObject (proc, INFINITE);
  switch (code) 
    {
      case WAIT_FAILED:
        log_error (_("waiting for process %d to terminate failed: %s\n"),
                   (int)pid, w32_strerror (-1));
        ec = GPG_ERR_GENERAL;
        break;

      case WAIT_OBJECT_0:
        if (!GetExitCodeProcess (proc, &exc))
          {
            log_error (_("error getting exit code of process %d: %s\n"),
                         (int)pid, w32_strerror (-1) );
            ec = GPG_ERR_GENERAL;
          }
        else if (exc)
          {
            log_error (_("error running `%s': exit status %d\n"),
                       pgmname, (int)exc );
            if (exitcode)
              *exitcode = (int)exc;
            ec = GPG_ERR_GENERAL;
          }
        else
          {
            if (exitcode)
              *exitcode = 0;
            ec = 0;
          }
        CloseHandle (proc);
        break;

      default:
        log_error ("WaitForSingleObject returned unexpected "
                   "code %d for pid %d\n", code, (int)pid );
        ec = GPG_ERR_GENERAL;
        break;
    }

  return gpg_err_make (GPG_ERR_SOURCE_DEFAULT, ec);
}


/* Spawn a new process and immediatley detach from it.  The name of
   the program to exec is PGMNAME and its arguments are in ARGV (the
   programname is automatically passed as first argument).
   Environment strings in ENVP are set.  An error is returned if
   pgmname is not executable; to make this work it is necessary to
   provide an absolute file name.  All standard file descriptors are
   connected to /dev/null. */
gpg_error_t
gnupg_spawn_process_detached (const char *pgmname, const char *argv[],
                              const char *envp[] )
{
  gpg_error_t err;
  SECURITY_ATTRIBUTES sec_attr;
  PROCESS_INFORMATION pi = 
    {
      NULL,      /* Returns process handle.  */
      0,         /* Returns primary thread handle.  */
      0,         /* Returns pid.  */
      0          /* Returns tid.  */
    };
  STARTUPINFO si;
  int cr_flags;
  char *cmdline;


  /* FIXME: We don't make use of ENVP yet.  It is currently only used
     to pass the GPG_AGENT_INFO variable to gpg-agent.  As the default
     on windows is to use a standard socket, this does not really
     matter.  */
  (void)envp;

  if (access (pgmname, X_OK))
    return gpg_error_from_syserror ();

  /* Prepare security attributes.  */
  memset (&sec_attr, 0, sizeof sec_attr );
  sec_attr.nLength = sizeof sec_attr;
  sec_attr.bInheritHandle = FALSE;
  
  /* Build the command line.  */
  err = build_w32_commandline (pgmname, argv, &cmdline);
  if (err)
    return err; 

  /* Start the process.  */
  memset (&si, 0, sizeof si);
  si.cb = sizeof (si);
  si.dwFlags = STARTF_USESHOWWINDOW;
  si.wShowWindow = DEBUG_W32_SPAWN? SW_SHOW : SW_MINIMIZE;

  cr_flags = (CREATE_DEFAULT_ERROR_MODE
              | GetPriorityClass (GetCurrentProcess ())
              | CREATE_NEW_PROCESS_GROUP
              | DETACHED_PROCESS); 
/*   log_debug ("CreateProcess(detached), path=`%s' cmdline=`%s'\n", */
/*              pgmname, cmdline); */
  if (!CreateProcess (pgmname,       /* Program to start.  */
                      cmdline,       /* Command line arguments.  */
                      &sec_attr,     /* Process security attributes.  */
                      &sec_attr,     /* Thread security attributes.  */
                      FALSE,         /* Inherit handles.  */
                      cr_flags,      /* Creation flags.  */
                      NULL,          /* Environment.  */
                      NULL,          /* Use current drive/directory.  */
                      &si,           /* Startup information. */
                      &pi            /* Returns process information.  */
                      ))
    {
      log_error ("CreateProcess(detached) failed: %s\n", w32_strerror (-1));
      xfree (cmdline);
      return gpg_error (GPG_ERR_GENERAL);
    }
  xfree (cmdline);
  cmdline = NULL;

/*   log_debug ("CreateProcess(detached) ready: hProcess=%p hThread=%p" */
/*              " dwProcessID=%d dwThreadId=%d\n", */
/*              pi.hProcess, pi.hThread, */
/*              (int) pi.dwProcessId, (int) pi.dwThreadId); */

  CloseHandle (pi.hThread); 

  return 0;
}


/* Kill a process; that is send an appropriate signal to the process.
   gnupg_wait_process must be called to actually remove the process
   from the system.  An invalid PID is ignored.  */
void
gnupg_kill_process (pid_t pid)
{
  if (pid != (pid_t) INVALID_HANDLE_VALUE)
    {
      HANDLE process = (HANDLE) pid;
      
      /* Arbitrary error code.  */
      TerminateProcess (process, 1);
    }
}