File: pex-unix.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 (789 lines) | stat: -rw-r--r-- 20,009 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
/* Utilities to execute a program in a subprocess (possibly linked by pipes
   with other subprocesses), and wait for it.  Generic Unix version
   (also used for UWIN and VMS).
   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 "config.h"
#include "libiberty.h"
#include "pex-common.h"
#include "environ.h"

#include <stdio.h>
#include <signal.h>
#include <errno.h>
#ifdef NEED_DECLARATION_ERRNO
extern int errno;
#endif
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

#include <sys/types.h>

#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif
#ifdef HAVE_SYS_WAIT_H
#include <sys/wait.h>
#endif
#ifdef HAVE_GETRUSAGE
#include <sys/time.h>
#include <sys/resource.h>
#endif
#ifdef HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#ifdef HAVE_PROCESS_H
#include <process.h>
#endif

#ifdef vfork /* Autoconf may define this to fork for us. */
# define VFORK_STRING "fork"
#else
# define VFORK_STRING "vfork"
#endif
#ifdef HAVE_VFORK_H
#include <vfork.h>
#endif
#if defined(VMS) && defined (__LONG_POINTERS)
#ifndef __CHAR_PTR32
typedef char * __char_ptr32
__attribute__ ((mode (SI)));
#endif

typedef __char_ptr32 *__char_ptr_char_ptr32
__attribute__ ((mode (SI)));

/* Return a 32 bit pointer to an array of 32 bit pointers 
   given a 64 bit pointer to an array of 64 bit pointers.  */

static __char_ptr_char_ptr32
to_ptr32 (char **ptr64)
{
  int argc;
  __char_ptr_char_ptr32 short_argv;

  /* Count number of arguments.  */
  for (argc = 0; ptr64[argc] != NULL; argc++)
    ;

  /* Reallocate argv with 32 bit pointers.  */
  short_argv = (__char_ptr_char_ptr32) decc$malloc
    (sizeof (__char_ptr32) * (argc + 1));

  for (argc = 0; ptr64[argc] != NULL; argc++)
    short_argv[argc] = (__char_ptr32) decc$strdup (ptr64[argc]);

  short_argv[argc] = (__char_ptr32) 0;
  return short_argv;

}
#else
#define to_ptr32(argv) argv
#endif

/* File mode to use for private and world-readable files.  */

#if defined (S_IRUSR) && defined (S_IWUSR) && defined (S_IRGRP) && defined (S_IWGRP) && defined (S_IROTH) && defined (S_IWOTH)
#define PUBLIC_MODE  \
    (S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH)
#else
#define PUBLIC_MODE 0666
#endif

/* Get the exit status of a particular process, and optionally get the
   time that it took.  This is simple if we have wait4, slightly
   harder if we have waitpid, and is a pain if we only have wait.  */

static pid_t pex_wait (struct pex_obj *, pid_t, int *, struct pex_time *);

#ifdef HAVE_WAIT4

static pid_t
pex_wait (struct pex_obj *obj ATTRIBUTE_UNUSED, pid_t pid, int *status,
	  struct pex_time *time)
{
  pid_t ret;
  struct rusage r;

#ifdef HAVE_WAITPID
  if (time == NULL)
    return waitpid (pid, status, 0);
#endif

  ret = wait4 (pid, status, 0, &r);

  if (time != NULL)
    {
      time->user_seconds = r.ru_utime.tv_sec;
      time->user_microseconds= r.ru_utime.tv_usec;
      time->system_seconds = r.ru_stime.tv_sec;
      time->system_microseconds= r.ru_stime.tv_usec;
    }

  return ret;
}

#else /* ! defined (HAVE_WAIT4) */

#ifdef HAVE_WAITPID

#ifndef HAVE_GETRUSAGE

static pid_t
pex_wait (struct pex_obj *obj ATTRIBUTE_UNUSED, pid_t pid, int *status,
	  struct pex_time *time)
{
  if (time != NULL)
    memset (time, 0, sizeof (struct pex_time));
  return waitpid (pid, status, 0);
}

#else /* defined (HAVE_GETRUSAGE) */

static pid_t
pex_wait (struct pex_obj *obj ATTRIBUTE_UNUSED, pid_t pid, int *status,
	  struct pex_time *time)
{
  struct rusage r1, r2;
  pid_t ret;

  if (time == NULL)
    return waitpid (pid, status, 0);

  getrusage (RUSAGE_CHILDREN, &r1);

  ret = waitpid (pid, status, 0);
  if (ret < 0)
    return ret;

  getrusage (RUSAGE_CHILDREN, &r2);

  time->user_seconds = r2.ru_utime.tv_sec - r1.ru_utime.tv_sec;
  time->user_microseconds = r2.ru_utime.tv_usec - r1.ru_utime.tv_usec;
  if (r2.ru_utime.tv_usec < r1.ru_utime.tv_usec)
    {
      --time->user_seconds;
      time->user_microseconds += 1000000;
    }

  time->system_seconds = r2.ru_stime.tv_sec - r1.ru_stime.tv_sec;
  time->system_microseconds = r2.ru_stime.tv_usec - r1.ru_stime.tv_usec;
  if (r2.ru_stime.tv_usec < r1.ru_stime.tv_usec)
    {
      --time->system_seconds;
      time->system_microseconds += 1000000;
    }

  return ret;
}

#endif /* defined (HAVE_GETRUSAGE) */

#else /* ! defined (HAVE_WAITPID) */

struct status_list
{
  struct status_list *next;
  pid_t pid;
  int status;
  struct pex_time time;
};

static pid_t
pex_wait (struct pex_obj *obj, pid_t pid, int *status, struct pex_time *time)
{
  struct status_list **pp;

  for (pp = (struct status_list **) &obj->sysdep;
       *pp != NULL;
       pp = &(*pp)->next)
    {
      if ((*pp)->pid == pid)
	{
	  struct status_list *p;

	  p = *pp;
	  *status = p->status;
	  if (time != NULL)
	    *time = p->time;
	  *pp = p->next;
	  free (p);
	  return pid;
	}
    }

  while (1)
    {
      pid_t cpid;
      struct status_list *psl;
      struct pex_time pt;
#ifdef HAVE_GETRUSAGE
      struct rusage r1, r2;
#endif

      if (time != NULL)
	{
#ifdef HAVE_GETRUSAGE
	  getrusage (RUSAGE_CHILDREN, &r1);
#else
	  memset (&pt, 0, sizeof (struct pex_time));
#endif
	}

      cpid = wait (status);

#ifdef HAVE_GETRUSAGE
      if (time != NULL && cpid >= 0)
	{
	  getrusage (RUSAGE_CHILDREN, &r2);

	  pt.user_seconds = r2.ru_utime.tv_sec - r1.ru_utime.tv_sec;
	  pt.user_microseconds = r2.ru_utime.tv_usec - r1.ru_utime.tv_usec;
	  if (pt.user_microseconds < 0)
	    {
	      --pt.user_seconds;
	      pt.user_microseconds += 1000000;
	    }

	  pt.system_seconds = r2.ru_stime.tv_sec - r1.ru_stime.tv_sec;
	  pt.system_microseconds = r2.ru_stime.tv_usec - r1.ru_stime.tv_usec;
	  if (pt.system_microseconds < 0)
	    {
	      --pt.system_seconds;
	      pt.system_microseconds += 1000000;
	    }
	}
#endif

      if (cpid < 0 || cpid == pid)
	{
	  if (time != NULL)
	    *time = pt;
	  return cpid;
	}

      psl = XNEW (struct status_list);
      psl->pid = cpid;
      psl->status = *status;
      if (time != NULL)
	psl->time = pt;
      psl->next = (struct status_list *) obj->sysdep;
      obj->sysdep = (void *) psl;
    }
}

#endif /* ! defined (HAVE_WAITPID) */
#endif /* ! defined (HAVE_WAIT4) */

static void pex_child_error (struct pex_obj *, const char *, const char *, int)
     ATTRIBUTE_NORETURN;
static int pex_unix_open_read (struct pex_obj *, const char *, int);
static int pex_unix_open_write (struct pex_obj *, const char *, int, int);
static pid_t pex_unix_exec_child (struct pex_obj *, int, const char *,
				 char * const *, char * const *,
				 int, int, int, int,
				 const char **, int *);
static int pex_unix_close (struct pex_obj *, int);
static int pex_unix_wait (struct pex_obj *, pid_t, int *, struct pex_time *,
			  int, const char **, int *);
static int pex_unix_pipe (struct pex_obj *, int *, int);
static FILE *pex_unix_fdopenr (struct pex_obj *, int, int);
static FILE *pex_unix_fdopenw (struct pex_obj *, int, int);
static void pex_unix_cleanup (struct pex_obj *);

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

const struct pex_funcs funcs =
{
  pex_unix_open_read,
  pex_unix_open_write,
  pex_unix_exec_child,
  pex_unix_close,
  pex_unix_wait,
  pex_unix_pipe,
  pex_unix_fdopenr,
  pex_unix_fdopenw,
  pex_unix_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_unix_open_read (struct pex_obj *obj ATTRIBUTE_UNUSED, const char *name,
		    int binary ATTRIBUTE_UNUSED)
{
  return open (name, O_RDONLY);
}

/* Open a file for writing.  */

static int
pex_unix_open_write (struct pex_obj *obj ATTRIBUTE_UNUSED, const char *name,
		     int binary ATTRIBUTE_UNUSED, int append)
{
  /* Note that we can't use O_EXCL here because gcc may have already
     created the temporary file via make_temp_file.  */
  return open (name, O_WRONLY | O_CREAT
		     | (append ? O_APPEND : O_TRUNC), PUBLIC_MODE);
}

/* Close a file.  */

static int
pex_unix_close (struct pex_obj *obj ATTRIBUTE_UNUSED, int fd)
{
  return close (fd);
}

/* Report an error from a child process.  We don't use stdio routines,
   because we might be here due to a vfork call.  */

static void
pex_child_error (struct pex_obj *obj, const char *executable,
		 const char *errmsg, int err)
{
  int retval = 0;
#define writeerr(s) retval |= (write (STDERR_FILE_NO, s, strlen (s)) < 0)
  writeerr (obj->pname);
  writeerr (": error trying to exec '");
  writeerr (executable);
  writeerr ("': ");
  writeerr (errmsg);
  writeerr (": ");
  writeerr (xstrerror (err));
  writeerr ("\n");
#undef writeerr
  /* Exit with -2 if the error output failed, too.  */
  _exit (retval == 0 ? -1 : -2);
}

/* Execute a child.  */

#if defined(HAVE_SPAWNVE) && defined(HAVE_SPAWNVPE)
/* Implementation of pex->exec_child using the Cygwin spawn operation.  */

/* Subroutine of pex_unix_exec_child.  Move OLD_FD to a new file descriptor
   to be stored in *PNEW_FD, save the flags in *PFLAGS, and arrange for the
   saved copy to be close-on-exec.  Move CHILD_FD into OLD_FD.  If CHILD_FD
   is -1, OLD_FD is to be closed.  Return -1 on error.  */

static int
save_and_install_fd(int *pnew_fd, int *pflags, int old_fd, int child_fd)
{
  int new_fd, flags;

  flags = fcntl (old_fd, F_GETFD);

  /* If we could not retrieve the flags, then OLD_FD was not open.  */
  if (flags < 0)
    {
      new_fd = -1, flags = 0;
      if (child_fd >= 0 && dup2 (child_fd, old_fd) < 0)
	return -1;
    }
  /* If we wish to close OLD_FD, just mark it CLOEXEC.  */
  else if (child_fd == -1)
    {
      new_fd = old_fd;
      if ((flags & FD_CLOEXEC) == 0 && fcntl (old_fd, F_SETFD, FD_CLOEXEC) < 0)
	return -1;
    }
  /* Otherwise we need to save a copy of OLD_FD before installing CHILD_FD.  */
  else
    {
#ifdef F_DUPFD_CLOEXEC
      new_fd = fcntl (old_fd, F_DUPFD_CLOEXEC, 3);
      if (new_fd < 0)
	return -1;
#else
      /* Prefer F_DUPFD over dup in order to avoid getting a new fd
	 in the range 0-2, right where a new stderr fd might get put.  */
      new_fd = fcntl (old_fd, F_DUPFD, 3);
      if (new_fd < 0)
	return -1;
      if (fcntl (new_fd, F_SETFD, FD_CLOEXEC) < 0)
	return -1;
#endif
      if (dup2 (child_fd, old_fd) < 0)
	return -1;
    }

  *pflags = flags;
  if (pnew_fd)
    *pnew_fd = new_fd;
  else if (new_fd != old_fd)
    abort ();

  return 0;
}

/* Subroutine of pex_unix_exec_child.  Move SAVE_FD back to OLD_FD
   restoring FLAGS.  If SAVE_FD < 0, OLD_FD is to be closed.  */

static int
restore_fd(int old_fd, int save_fd, int flags)
{
  /* For SAVE_FD < 0, all we have to do is restore the
     "closed-ness" of the original.  */
  if (save_fd < 0)
    return close (old_fd);

  /* For SAVE_FD == OLD_FD, all we have to do is restore the
     original setting of the CLOEXEC flag.  */
  if (save_fd == old_fd)
    {
      if (flags & FD_CLOEXEC)
	return 0;
      return fcntl (old_fd, F_SETFD, flags);
    }

  /* Otherwise we have to move the descriptor back, restore the flags,
     and close the saved copy.  */
#ifdef HAVE_DUP3
  if (flags == FD_CLOEXEC)
    {
      if (dup3 (save_fd, old_fd, O_CLOEXEC) < 0)
	return -1;
    }
  else
#endif
    {
      if (dup2 (save_fd, old_fd) < 0)
	return -1;
      if (flags != 0 && fcntl (old_fd, F_SETFD, flags) < 0)
	return -1;
    }
  return close (save_fd);
}

static pid_t
pex_unix_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,
		     const char **errmsg, int *err)
{
  int fl_in = 0, fl_out = 0, fl_err = 0, fl_tc = 0;
  int save_in = -1, save_out = -1, save_err = -1;
  int max, retries;
  pid_t pid;

  if (flags & PEX_STDERR_TO_STDOUT)
    errdes = out;

  /* We need the three standard file descriptors to be set up as for
     the child before we perform the spawn.  The file descriptors for
     the parent need to be moved and marked for close-on-exec.  */
  if (in != STDIN_FILE_NO
      && save_and_install_fd (&save_in, &fl_in, STDIN_FILE_NO, in) < 0)
    goto error_dup2;
  if (out != STDOUT_FILE_NO
      && save_and_install_fd (&save_out, &fl_out, STDOUT_FILE_NO, out) < 0)
    goto error_dup2;
  if (errdes != STDERR_FILE_NO
      && save_and_install_fd (&save_err, &fl_err, STDERR_FILE_NO, errdes) < 0)
    goto error_dup2;
  if (toclose >= 0
      && save_and_install_fd (NULL, &fl_tc, toclose, -1) < 0)
    goto error_dup2;

  /* Now that we've moved the file descriptors for the child into place,
     close the originals.  Be careful not to close any of the standard
     file descriptors that we just set up.  */
  max = -1;
  if (errdes >= 0)
    max = STDERR_FILE_NO;
  else if (out >= 0)
    max = STDOUT_FILE_NO;
  else if (in >= 0)
    max = STDIN_FILE_NO;
  if (in > max)
    close (in);
  if (out > max)
    close (out);
  if (errdes > max && errdes != out)
    close (errdes);

  /* If we were not given an environment, use the global environment.  */
  if (env == NULL)
    env = environ;

  /* Launch the program.  If we get EAGAIN (normally out of pid's), try
     again a few times with increasing backoff times.  */
  retries = 0;
  while (1)
    {
      typedef const char * const *cc_cp;

      if (flags & PEX_SEARCH)
	pid = spawnvpe (_P_NOWAITO, executable, (cc_cp)argv, (cc_cp)env);
      else
	pid = spawnve (_P_NOWAITO, executable, (cc_cp)argv, (cc_cp)env);

      if (pid > 0)
	break;

      *err = errno;
      *errmsg = "spawn";
      if (errno != EAGAIN || ++retries == 4)
	return (pid_t) -1;
      sleep (1 << retries);
    }

  /* Success.  Restore the parent's file descriptors that we saved above.  */
  if (toclose >= 0
      && restore_fd (toclose, toclose, fl_tc) < 0)
    goto error_dup2;
  if (in != STDIN_FILE_NO
      && restore_fd (STDIN_FILE_NO, save_in, fl_in) < 0)
    goto error_dup2;
  if (out != STDOUT_FILE_NO
      && restore_fd (STDOUT_FILE_NO, save_out, fl_out) < 0)
    goto error_dup2;
  if (errdes != STDERR_FILE_NO
      && restore_fd (STDERR_FILE_NO, save_err, fl_err) < 0)
    goto error_dup2;

  return pid;

 error_dup2:
  *err = errno;
  *errmsg = "dup2";
  return (pid_t) -1;
}

#else
/* Implementation of pex->exec_child using standard vfork + exec.  */

static pid_t
pex_unix_exec_child (struct pex_obj *obj, int flags, const char *executable,
		     char * const * argv, char * const * env,
                     int in, int out, int errdes,
		     int toclose, const char **errmsg, int *err)
{
  pid_t pid;

  /* We declare these to be volatile to avoid warnings from gcc about
     them being clobbered by vfork.  */
  volatile int sleep_interval;
  volatile int retries;

  /* We vfork and then set environ in the child before calling execvp.
     This clobbers the parent's environ so we need to restore it.
     It would be nice to use one of the exec* functions that takes an
     environment as a parameter, but that may have portability issues.  */
  char **save_environ = environ;

  sleep_interval = 1;
  pid = -1;
  for (retries = 0; retries < 4; ++retries)
    {
      pid = vfork ();
      if (pid >= 0)
	break;
      sleep (sleep_interval);
      sleep_interval *= 2;
    }

  switch (pid)
    {
    case -1:
      *err = errno;
      *errmsg = VFORK_STRING;
      return (pid_t) -1;

    case 0:
      /* Child process.  */
      if (in != STDIN_FILE_NO)
	{
	  if (dup2 (in, STDIN_FILE_NO) < 0)
	    pex_child_error (obj, executable, "dup2", errno);
	  if (close (in) < 0)
	    pex_child_error (obj, executable, "close", errno);
	}
      if (out != STDOUT_FILE_NO)
	{
	  if (dup2 (out, STDOUT_FILE_NO) < 0)
	    pex_child_error (obj, executable, "dup2", errno);
	  if (close (out) < 0)
	    pex_child_error (obj, executable, "close", errno);
	}
      if (errdes != STDERR_FILE_NO)
	{
	  if (dup2 (errdes, STDERR_FILE_NO) < 0)
	    pex_child_error (obj, executable, "dup2", errno);
	  if (close (errdes) < 0)
	    pex_child_error (obj, executable, "close", errno);
	}
      if (toclose >= 0)
	{
	  if (close (toclose) < 0)
	    pex_child_error (obj, executable, "close", errno);
	}
      if ((flags & PEX_STDERR_TO_STDOUT) != 0)
	{
	  if (dup2 (STDOUT_FILE_NO, STDERR_FILE_NO) < 0)
	    pex_child_error (obj, executable, "dup2", errno);
	}

      if (env)
	{
	  /* NOTE: In a standard vfork implementation this clobbers the
	     parent's copy of environ "too" (in reality there's only one copy).
	     This is ok as we restore it below.  */
	  environ = (char**) env;
	}

      if ((flags & PEX_SEARCH) != 0)
	{
	  execvp (executable, to_ptr32 (argv));
	  pex_child_error (obj, executable, "execvp", errno);
	}
      else
	{
	  execv (executable, to_ptr32 (argv));
	  pex_child_error (obj, executable, "execv", errno);
	}

      /* NOTREACHED */
      return (pid_t) -1;

    default:
      /* Parent process.  */

      /* Restore environ.
	 Note that the parent either doesn't run until the child execs/exits
	 (standard vfork behaviour), or if it does run then vfork is behaving
	 more like fork.  In either case we needn't worry about clobbering
	 the child's copy of environ.  */
      environ = save_environ;

      if (in != STDIN_FILE_NO)
	{
	  if (close (in) < 0)
	    {
	      *err = errno;
	      *errmsg = "close";
	      return (pid_t) -1;
	    }
	}
      if (out != STDOUT_FILE_NO)
	{
	  if (close (out) < 0)
	    {
	      *err = errno;
	      *errmsg = "close";
	      return (pid_t) -1;
	    }
	}
      if (errdes != STDERR_FILE_NO)
	{
	  if (close (errdes) < 0)
	    {
	      *err = errno;
	      *errmsg = "close";
	      return (pid_t) -1;
	    }
	}

      return pid;
    }
}
#endif /* SPAWN */

/* Wait for a child process to complete.  */

static int
pex_unix_wait (struct pex_obj *obj, pid_t pid, int *status,
	       struct pex_time *time, int done, const char **errmsg,
	       int *err)
{
  /* If we are cleaning up when the caller didn't retrieve process
     status for some reason, encourage the process to go away.  */
  if (done)
    kill (pid, SIGTERM);

  if (pex_wait (obj, pid, status, time) < 0)
    {
      *err = errno;
      *errmsg = "wait";
      return -1;
    }

  return 0;
}

/* Create a pipe.  */

static int
pex_unix_pipe (struct pex_obj *obj ATTRIBUTE_UNUSED, int *p,
	       int binary ATTRIBUTE_UNUSED)
{
  return pipe (p);
}

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

static FILE *
pex_unix_fdopenr (struct pex_obj *obj ATTRIBUTE_UNUSED, int fd,
		  int binary ATTRIBUTE_UNUSED)
{
  return fdopen (fd, "r");
}

static FILE *
pex_unix_fdopenw (struct pex_obj *obj ATTRIBUTE_UNUSED, int fd,
		  int binary ATTRIBUTE_UNUSED)
{
  if (fcntl (fd, F_SETFD, FD_CLOEXEC) < 0)
    return NULL;
  return fdopen (fd, "w");
}

static void
pex_unix_cleanup (struct pex_obj *obj ATTRIBUTE_UNUSED)
{
#if !defined (HAVE_WAIT4) && !defined (HAVE_WAITPID)
  while (obj->sysdep != NULL)
    {
      struct status_list *this;
      struct status_list *next;

      this = (struct status_list *) obj->sysdep;
      next = this->next;
      free (this);
      obj->sysdep = (void *) next;
    }
#endif
}