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      1 /* Utilities to execute a program in a subprocess (possibly linked by pipes
      2    with other subprocesses), and wait for it.  Generic Unix version
      3    (also used for UWIN and VMS).
      4    Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2003, 2004, 2005, 2009,
      5    2010 Free Software Foundation, Inc.
      6 
      7 This file is part of the libiberty library.
      8 Libiberty is free software; you can redistribute it and/or
      9 modify it under the terms of the GNU Library General Public
     10 License as published by the Free Software Foundation; either
     11 version 2 of the License, or (at your option) any later version.
     12 
     13 Libiberty is distributed in the hope that it will be useful,
     14 but WITHOUT ANY WARRANTY; without even the implied warranty of
     15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     16 Library General Public License for more details.
     17 
     18 You should have received a copy of the GNU Library General Public
     19 License along with libiberty; see the file COPYING.LIB.  If not,
     20 write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
     21 Boston, MA 02110-1301, USA.  */
     22 
     23 #include "config.h"
     24 #include "libiberty.h"
     25 #include "pex-common.h"
     26 
     27 #include <stdio.h>
     28 #include <signal.h>
     29 #include <errno.h>
     30 #ifdef NEED_DECLARATION_ERRNO
     31 extern int errno;
     32 #endif
     33 #ifdef HAVE_STDLIB_H
     34 #include <stdlib.h>
     35 #endif
     36 #ifdef HAVE_STRING_H
     37 #include <string.h>
     38 #endif
     39 #ifdef HAVE_UNISTD_H
     40 #include <unistd.h>
     41 #endif
     42 
     43 #include <sys/types.h>
     44 
     45 #ifdef HAVE_FCNTL_H
     46 #include <fcntl.h>
     47 #endif
     48 #ifdef HAVE_SYS_WAIT_H
     49 #include <sys/wait.h>
     50 #endif
     51 #ifdef HAVE_GETRUSAGE
     52 #include <sys/time.h>
     53 #include <sys/resource.h>
     54 #endif
     55 #ifdef HAVE_SYS_STAT_H
     56 #include <sys/stat.h>
     57 #endif
     58 #ifdef HAVE_PROCESS_H
     59 #include <process.h>
     60 #endif
     61 
     62 #ifdef vfork /* Autoconf may define this to fork for us. */
     63 # define VFORK_STRING "fork"
     64 #else
     65 # define VFORK_STRING "vfork"
     66 #endif
     67 #ifdef HAVE_VFORK_H
     68 #include <vfork.h>
     69 #endif
     70 #if defined(VMS) && defined (__LONG_POINTERS)
     71 #ifndef __CHAR_PTR32
     72 typedef char * __char_ptr32
     73 __attribute__ ((mode (SI)));
     74 #endif
     75 
     76 typedef __char_ptr32 *__char_ptr_char_ptr32
     77 __attribute__ ((mode (SI)));
     78 
     79 /* Return a 32 bit pointer to an array of 32 bit pointers
     80    given a 64 bit pointer to an array of 64 bit pointers.  */
     81 
     82 static __char_ptr_char_ptr32
     83 to_ptr32 (char **ptr64)
     84 {
     85   int argc;
     86   __char_ptr_char_ptr32 short_argv;
     87 
     88   /* Count number of arguments.  */
     89   for (argc = 0; ptr64[argc] != NULL; argc++)
     90     ;
     91 
     92   /* Reallocate argv with 32 bit pointers.  */
     93   short_argv = (__char_ptr_char_ptr32) decc$malloc
     94     (sizeof (__char_ptr32) * (argc + 1));
     95 
     96   for (argc = 0; ptr64[argc] != NULL; argc++)
     97     short_argv[argc] = (__char_ptr32) decc$strdup (ptr64[argc]);
     98 
     99   short_argv[argc] = (__char_ptr32) 0;
    100   return short_argv;
    101 
    102 }
    103 #else
    104 #define to_ptr32(argv) argv
    105 #endif
    106 
    107 /* File mode to use for private and world-readable files.  */
    108 
    109 #if defined (S_IRUSR) && defined (S_IWUSR) && defined (S_IRGRP) && defined (S_IWGRP) && defined (S_IROTH) && defined (S_IWOTH)
    110 #define PUBLIC_MODE  \
    111     (S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH)
    112 #else
    113 #define PUBLIC_MODE 0666
    114 #endif
    115 
    116 /* Get the exit status of a particular process, and optionally get the
    117    time that it took.  This is simple if we have wait4, slightly
    118    harder if we have waitpid, and is a pain if we only have wait.  */
    119 
    120 static pid_t pex_wait (struct pex_obj *, pid_t, int *, struct pex_time *);
    121 
    122 #ifdef HAVE_WAIT4
    123 
    124 static pid_t
    125 pex_wait (struct pex_obj *obj ATTRIBUTE_UNUSED, pid_t pid, int *status,
    126 	  struct pex_time *time)
    127 {
    128   pid_t ret;
    129   struct rusage r;
    130 
    131 #ifdef HAVE_WAITPID
    132   if (time == NULL)
    133     return waitpid (pid, status, 0);
    134 #endif
    135 
    136   ret = wait4 (pid, status, 0, &r);
    137 
    138   if (time != NULL)
    139     {
    140       time->user_seconds = r.ru_utime.tv_sec;
    141       time->user_microseconds= r.ru_utime.tv_usec;
    142       time->system_seconds = r.ru_stime.tv_sec;
    143       time->system_microseconds= r.ru_stime.tv_usec;
    144     }
    145 
    146   return ret;
    147 }
    148 
    149 #else /* ! defined (HAVE_WAIT4) */
    150 
    151 #ifdef HAVE_WAITPID
    152 
    153 #ifndef HAVE_GETRUSAGE
    154 
    155 static pid_t
    156 pex_wait (struct pex_obj *obj ATTRIBUTE_UNUSED, pid_t pid, int *status,
    157 	  struct pex_time *time)
    158 {
    159   if (time != NULL)
    160     memset (time, 0, sizeof (struct pex_time));
    161   return waitpid (pid, status, 0);
    162 }
    163 
    164 #else /* defined (HAVE_GETRUSAGE) */
    165 
    166 static pid_t
    167 pex_wait (struct pex_obj *obj ATTRIBUTE_UNUSED, pid_t pid, int *status,
    168 	  struct pex_time *time)
    169 {
    170   struct rusage r1, r2;
    171   pid_t ret;
    172 
    173   if (time == NULL)
    174     return waitpid (pid, status, 0);
    175 
    176   getrusage (RUSAGE_CHILDREN, &r1);
    177 
    178   ret = waitpid (pid, status, 0);
    179   if (ret < 0)
    180     return ret;
    181 
    182   getrusage (RUSAGE_CHILDREN, &r2);
    183 
    184   time->user_seconds = r2.ru_utime.tv_sec - r1.ru_utime.tv_sec;
    185   time->user_microseconds = r2.ru_utime.tv_usec - r1.ru_utime.tv_usec;
    186   if (r2.ru_utime.tv_usec < r1.ru_utime.tv_usec)
    187     {
    188       --time->user_seconds;
    189       time->user_microseconds += 1000000;
    190     }
    191 
    192   time->system_seconds = r2.ru_stime.tv_sec - r1.ru_stime.tv_sec;
    193   time->system_microseconds = r2.ru_stime.tv_usec - r1.ru_stime.tv_usec;
    194   if (r2.ru_stime.tv_usec < r1.ru_stime.tv_usec)
    195     {
    196       --time->system_seconds;
    197       time->system_microseconds += 1000000;
    198     }
    199 
    200   return ret;
    201 }
    202 
    203 #endif /* defined (HAVE_GETRUSAGE) */
    204 
    205 #else /* ! defined (HAVE_WAITPID) */
    206 
    207 struct status_list
    208 {
    209   struct status_list *next;
    210   pid_t pid;
    211   int status;
    212   struct pex_time time;
    213 };
    214 
    215 static pid_t
    216 pex_wait (struct pex_obj *obj, pid_t pid, int *status, struct pex_time *time)
    217 {
    218   struct status_list **pp;
    219 
    220   for (pp = (struct status_list **) &obj->sysdep;
    221        *pp != NULL;
    222        pp = &(*pp)->next)
    223     {
    224       if ((*pp)->pid == pid)
    225 	{
    226 	  struct status_list *p;
    227 
    228 	  p = *pp;
    229 	  *status = p->status;
    230 	  if (time != NULL)
    231 	    *time = p->time;
    232 	  *pp = p->next;
    233 	  free (p);
    234 	  return pid;
    235 	}
    236     }
    237 
    238   while (1)
    239     {
    240       pid_t cpid;
    241       struct status_list *psl;
    242       struct pex_time pt;
    243 #ifdef HAVE_GETRUSAGE
    244       struct rusage r1, r2;
    245 #endif
    246 
    247       if (time != NULL)
    248 	{
    249 #ifdef HAVE_GETRUSAGE
    250 	  getrusage (RUSAGE_CHILDREN, &r1);
    251 #else
    252 	  memset (&pt, 0, sizeof (struct pex_time));
    253 #endif
    254 	}
    255 
    256       cpid = wait (status);
    257 
    258 #ifdef HAVE_GETRUSAGE
    259       if (time != NULL && cpid >= 0)
    260 	{
    261 	  getrusage (RUSAGE_CHILDREN, &r2);
    262 
    263 	  pt.user_seconds = r2.ru_utime.tv_sec - r1.ru_utime.tv_sec;
    264 	  pt.user_microseconds = r2.ru_utime.tv_usec - r1.ru_utime.tv_usec;
    265 	  if (pt.user_microseconds < 0)
    266 	    {
    267 	      --pt.user_seconds;
    268 	      pt.user_microseconds += 1000000;
    269 	    }
    270 
    271 	  pt.system_seconds = r2.ru_stime.tv_sec - r1.ru_stime.tv_sec;
    272 	  pt.system_microseconds = r2.ru_stime.tv_usec - r1.ru_stime.tv_usec;
    273 	  if (pt.system_microseconds < 0)
    274 	    {
    275 	      --pt.system_seconds;
    276 	      pt.system_microseconds += 1000000;
    277 	    }
    278 	}
    279 #endif
    280 
    281       if (cpid < 0 || cpid == pid)
    282 	{
    283 	  if (time != NULL)
    284 	    *time = pt;
    285 	  return cpid;
    286 	}
    287 
    288       psl = XNEW (struct status_list);
    289       psl->pid = cpid;
    290       psl->status = *status;
    291       if (time != NULL)
    292 	psl->time = pt;
    293       psl->next = (struct status_list *) obj->sysdep;
    294       obj->sysdep = (void *) psl;
    295     }
    296 }
    297 
    298 #endif /* ! defined (HAVE_WAITPID) */
    299 #endif /* ! defined (HAVE_WAIT4) */
    300 
    301 static void pex_child_error (struct pex_obj *, const char *, const char *, int)
    302      ATTRIBUTE_NORETURN;
    303 static int pex_unix_open_read (struct pex_obj *, const char *, int);
    304 static int pex_unix_open_write (struct pex_obj *, const char *, int, int);
    305 static pid_t pex_unix_exec_child (struct pex_obj *, int, const char *,
    306 				 char * const *, char * const *,
    307 				 int, int, int, int,
    308 				 const char **, int *);
    309 static int pex_unix_close (struct pex_obj *, int);
    310 static int pex_unix_wait (struct pex_obj *, pid_t, int *, struct pex_time *,
    311 			  int, const char **, int *);
    312 static int pex_unix_pipe (struct pex_obj *, int *, int);
    313 static FILE *pex_unix_fdopenr (struct pex_obj *, int, int);
    314 static FILE *pex_unix_fdopenw (struct pex_obj *, int, int);
    315 static void pex_unix_cleanup (struct pex_obj *);
    316 
    317 /* The list of functions we pass to the common routines.  */
    318 
    319 const struct pex_funcs funcs =
    320 {
    321   pex_unix_open_read,
    322   pex_unix_open_write,
    323   pex_unix_exec_child,
    324   pex_unix_close,
    325   pex_unix_wait,
    326   pex_unix_pipe,
    327   pex_unix_fdopenr,
    328   pex_unix_fdopenw,
    329   pex_unix_cleanup
    330 };
    331 
    332 /* Return a newly initialized pex_obj structure.  */
    333 
    334 struct pex_obj *
    335 pex_init (int flags, const char *pname, const char *tempbase)
    336 {
    337   return pex_init_common (flags, pname, tempbase, &funcs);
    338 }
    339 
    340 /* Open a file for reading.  */
    341 
    342 static int
    343 pex_unix_open_read (struct pex_obj *obj ATTRIBUTE_UNUSED, const char *name,
    344 		    int binary ATTRIBUTE_UNUSED)
    345 {
    346   return open (name, O_RDONLY);
    347 }
    348 
    349 /* Open a file for writing.  */
    350 
    351 static int
    352 pex_unix_open_write (struct pex_obj *obj ATTRIBUTE_UNUSED, const char *name,
    353 		     int binary ATTRIBUTE_UNUSED, int append)
    354 {
    355   /* Note that we can't use O_EXCL here because gcc may have already
    356      created the temporary file via make_temp_file.  */
    357   return open (name, O_WRONLY | O_CREAT
    358 		     | (append ? O_APPEND : O_TRUNC), PUBLIC_MODE);
    359 }
    360 
    361 /* Close a file.  */
    362 
    363 static int
    364 pex_unix_close (struct pex_obj *obj ATTRIBUTE_UNUSED, int fd)
    365 {
    366   return close (fd);
    367 }
    368 
    369 /* Report an error from a child process.  We don't use stdio routines,
    370    because we might be here due to a vfork call.  */
    371 
    372 static void
    373 pex_child_error (struct pex_obj *obj, const char *executable,
    374 		 const char *errmsg, int err)
    375 {
    376   int retval = 0;
    377 #define writeerr(s) retval |= (write (STDERR_FILE_NO, s, strlen (s)) < 0)
    378   writeerr (obj->pname);
    379   writeerr (": error trying to exec '");
    380   writeerr (executable);
    381   writeerr ("': ");
    382   writeerr (errmsg);
    383   writeerr (": ");
    384   writeerr (xstrerror (err));
    385   writeerr ("\n");
    386 #undef writeerr
    387   /* Exit with -2 if the error output failed, too.  */
    388   _exit (retval == 0 ? -1 : -2);
    389 }
    390 
    391 /* Execute a child.  */
    392 
    393 extern char **environ;
    394 
    395 #if defined(HAVE_SPAWNVE) && defined(HAVE_SPAWNVPE)
    396 /* Implementation of pex->exec_child using the Cygwin spawn operation.  */
    397 
    398 /* Subroutine of pex_unix_exec_child.  Move OLD_FD to a new file descriptor
    399    to be stored in *PNEW_FD, save the flags in *PFLAGS, and arrange for the
    400    saved copy to be close-on-exec.  Move CHILD_FD into OLD_FD.  If CHILD_FD
    401    is -1, OLD_FD is to be closed.  Return -1 on error.  */
    402 
    403 static int
    404 save_and_install_fd(int *pnew_fd, int *pflags, int old_fd, int child_fd)
    405 {
    406   int new_fd, flags;
    407 
    408   flags = fcntl (old_fd, F_GETFD);
    409 
    410   /* If we could not retrieve the flags, then OLD_FD was not open.  */
    411   if (flags < 0)
    412     {
    413       new_fd = -1, flags = 0;
    414       if (child_fd >= 0 && dup2 (child_fd, old_fd) < 0)
    415 	return -1;
    416     }
    417   /* If we wish to close OLD_FD, just mark it CLOEXEC.  */
    418   else if (child_fd == -1)
    419     {
    420       new_fd = old_fd;
    421       if ((flags & FD_CLOEXEC) == 0 && fcntl (old_fd, F_SETFD, FD_CLOEXEC) < 0)
    422 	return -1;
    423     }
    424   /* Otherwise we need to save a copy of OLD_FD before installing CHILD_FD.  */
    425   else
    426     {
    427 #ifdef F_DUPFD_CLOEXEC
    428       new_fd = fcntl (old_fd, F_DUPFD_CLOEXEC, 3);
    429       if (new_fd < 0)
    430 	return -1;
    431 #else
    432       /* Prefer F_DUPFD over dup in order to avoid getting a new fd
    433 	 in the range 0-2, right where a new stderr fd might get put.  */
    434       new_fd = fcntl (old_fd, F_DUPFD, 3);
    435       if (new_fd < 0)
    436 	return -1;
    437       if (fcntl (new_fd, F_SETFD, FD_CLOEXEC) < 0)
    438 	return -1;
    439 #endif
    440       if (dup2 (child_fd, old_fd) < 0)
    441 	return -1;
    442     }
    443 
    444   *pflags = flags;
    445   if (pnew_fd)
    446     *pnew_fd = new_fd;
    447   else if (new_fd != old_fd)
    448     abort ();
    449 
    450   return 0;
    451 }
    452 
    453 /* Subroutine of pex_unix_exec_child.  Move SAVE_FD back to OLD_FD
    454    restoring FLAGS.  If SAVE_FD < 0, OLD_FD is to be closed.  */
    455 
    456 static int
    457 restore_fd(int old_fd, int save_fd, int flags)
    458 {
    459   /* For SAVE_FD < 0, all we have to do is restore the
    460      "closed-ness" of the original.  */
    461   if (save_fd < 0)
    462     return close (old_fd);
    463 
    464   /* For SAVE_FD == OLD_FD, all we have to do is restore the
    465      original setting of the CLOEXEC flag.  */
    466   if (save_fd == old_fd)
    467     {
    468       if (flags & FD_CLOEXEC)
    469 	return 0;
    470       return fcntl (old_fd, F_SETFD, flags);
    471     }
    472 
    473   /* Otherwise we have to move the descriptor back, restore the flags,
    474      and close the saved copy.  */
    475 #ifdef HAVE_DUP3
    476   if (flags == FD_CLOEXEC)
    477     {
    478       if (dup3 (save_fd, old_fd, O_CLOEXEC) < 0)
    479 	return -1;
    480     }
    481   else
    482 #endif
    483     {
    484       if (dup2 (save_fd, old_fd) < 0)
    485 	return -1;
    486       if (flags != 0 && fcntl (old_fd, F_SETFD, flags) < 0)
    487 	return -1;
    488     }
    489   return close (save_fd);
    490 }
    491 
    492 static pid_t
    493 pex_unix_exec_child (struct pex_obj *obj ATTRIBUTE_UNUSED,
    494 		     int flags, const char *executable,
    495 		     char * const * argv, char * const * env,
    496                      int in, int out, int errdes, int toclose,
    497 		     const char **errmsg, int *err)
    498 {
    499   int fl_in = 0, fl_out = 0, fl_err = 0, fl_tc = 0;
    500   int save_in = -1, save_out = -1, save_err = -1;
    501   int max, retries;
    502   pid_t pid;
    503 
    504   if (flags & PEX_STDERR_TO_STDOUT)
    505     errdes = out;
    506 
    507   /* We need the three standard file descriptors to be set up as for
    508      the child before we perform the spawn.  The file descriptors for
    509      the parent need to be moved and marked for close-on-exec.  */
    510   if (in != STDIN_FILE_NO
    511       && save_and_install_fd (&save_in, &fl_in, STDIN_FILE_NO, in) < 0)
    512     goto error_dup2;
    513   if (out != STDOUT_FILE_NO
    514       && save_and_install_fd (&save_out, &fl_out, STDOUT_FILE_NO, out) < 0)
    515     goto error_dup2;
    516   if (errdes != STDERR_FILE_NO
    517       && save_and_install_fd (&save_err, &fl_err, STDERR_FILE_NO, errdes) < 0)
    518     goto error_dup2;
    519   if (toclose >= 0
    520       && save_and_install_fd (NULL, &fl_tc, toclose, -1) < 0)
    521     goto error_dup2;
    522 
    523   /* Now that we've moved the file descriptors for the child into place,
    524      close the originals.  Be careful not to close any of the standard
    525      file descriptors that we just set up.  */
    526   max = -1;
    527   if (errdes >= 0)
    528     max = STDERR_FILE_NO;
    529   else if (out >= 0)
    530     max = STDOUT_FILE_NO;
    531   else if (in >= 0)
    532     max = STDIN_FILE_NO;
    533   if (in > max)
    534     close (in);
    535   if (out > max)
    536     close (out);
    537   if (errdes > max && errdes != out)
    538     close (errdes);
    539 
    540   /* If we were not given an environment, use the global environment.  */
    541   if (env == NULL)
    542     env = environ;
    543 
    544   /* Launch the program.  If we get EAGAIN (normally out of pid's), try
    545      again a few times with increasing backoff times.  */
    546   retries = 0;
    547   while (1)
    548     {
    549       typedef const char * const *cc_cp;
    550 
    551       if (flags & PEX_SEARCH)
    552 	pid = spawnvpe (_P_NOWAITO, executable, (cc_cp)argv, (cc_cp)env);
    553       else
    554 	pid = spawnve (_P_NOWAITO, executable, (cc_cp)argv, (cc_cp)env);
    555 
    556       if (pid > 0)
    557 	break;
    558 
    559       *err = errno;
    560       *errmsg = "spawn";
    561       if (errno != EAGAIN || ++retries == 4)
    562 	return (pid_t) -1;
    563       sleep (1 << retries);
    564     }
    565 
    566   /* Success.  Restore the parent's file descriptors that we saved above.  */
    567   if (toclose >= 0
    568       && restore_fd (toclose, toclose, fl_tc) < 0)
    569     goto error_dup2;
    570   if (in != STDIN_FILE_NO
    571       && restore_fd (STDIN_FILE_NO, save_in, fl_in) < 0)
    572     goto error_dup2;
    573   if (out != STDOUT_FILE_NO
    574       && restore_fd (STDOUT_FILE_NO, save_out, fl_out) < 0)
    575     goto error_dup2;
    576   if (errdes != STDERR_FILE_NO
    577       && restore_fd (STDERR_FILE_NO, save_err, fl_err) < 0)
    578     goto error_dup2;
    579 
    580   return pid;
    581 
    582  error_dup2:
    583   *err = errno;
    584   *errmsg = "dup2";
    585   return (pid_t) -1;
    586 }
    587 
    588 #else
    589 /* Implementation of pex->exec_child using standard vfork + exec.  */
    590 
    591 static pid_t
    592 pex_unix_exec_child (struct pex_obj *obj, int flags, const char *executable,
    593 		     char * const * argv, char * const * env,
    594                      int in, int out, int errdes,
    595 		     int toclose, const char **errmsg, int *err)
    596 {
    597   pid_t pid;
    598 
    599   /* We declare these to be volatile to avoid warnings from gcc about
    600      them being clobbered by vfork.  */
    601   volatile int sleep_interval;
    602   volatile int retries;
    603 
    604   /* We vfork and then set environ in the child before calling execvp.
    605      This clobbers the parent's environ so we need to restore it.
    606      It would be nice to use one of the exec* functions that takes an
    607      environment as a parameter, but that may have portability issues.  */
    608   char **save_environ = environ;
    609 
    610   sleep_interval = 1;
    611   pid = -1;
    612   for (retries = 0; retries < 4; ++retries)
    613     {
    614       pid = vfork ();
    615       if (pid >= 0)
    616 	break;
    617       sleep (sleep_interval);
    618       sleep_interval *= 2;
    619     }
    620 
    621   switch (pid)
    622     {
    623     case -1:
    624       *err = errno;
    625       *errmsg = VFORK_STRING;
    626       return (pid_t) -1;
    627 
    628     case 0:
    629       /* Child process.  */
    630       if (in != STDIN_FILE_NO)
    631 	{
    632 	  if (dup2 (in, STDIN_FILE_NO) < 0)
    633 	    pex_child_error (obj, executable, "dup2", errno);
    634 	  if (close (in) < 0)
    635 	    pex_child_error (obj, executable, "close", errno);
    636 	}
    637       if (out != STDOUT_FILE_NO)
    638 	{
    639 	  if (dup2 (out, STDOUT_FILE_NO) < 0)
    640 	    pex_child_error (obj, executable, "dup2", errno);
    641 	  if (close (out) < 0)
    642 	    pex_child_error (obj, executable, "close", errno);
    643 	}
    644       if (errdes != STDERR_FILE_NO)
    645 	{
    646 	  if (dup2 (errdes, STDERR_FILE_NO) < 0)
    647 	    pex_child_error (obj, executable, "dup2", errno);
    648 	  if (close (errdes) < 0)
    649 	    pex_child_error (obj, executable, "close", errno);
    650 	}
    651       if (toclose >= 0)
    652 	{
    653 	  if (close (toclose) < 0)
    654 	    pex_child_error (obj, executable, "close", errno);
    655 	}
    656       if ((flags & PEX_STDERR_TO_STDOUT) != 0)
    657 	{
    658 	  if (dup2 (STDOUT_FILE_NO, STDERR_FILE_NO) < 0)
    659 	    pex_child_error (obj, executable, "dup2", errno);
    660 	}
    661 
    662       if (env)
    663 	{
    664 	  /* NOTE: In a standard vfork implementation this clobbers the
    665 	     parent's copy of environ "too" (in reality there's only one copy).
    666 	     This is ok as we restore it below.  */
    667 	  environ = (char**) env;
    668 	}
    669 
    670       if ((flags & PEX_SEARCH) != 0)
    671 	{
    672 	  execvp (executable, to_ptr32 (argv));
    673 	  pex_child_error (obj, executable, "execvp", errno);
    674 	}
    675       else
    676 	{
    677 	  execv (executable, to_ptr32 (argv));
    678 	  pex_child_error (obj, executable, "execv", errno);
    679 	}
    680 
    681       /* NOTREACHED */
    682       return (pid_t) -1;
    683 
    684     default:
    685       /* Parent process.  */
    686 
    687       /* Restore environ.
    688 	 Note that the parent either doesn't run until the child execs/exits
    689 	 (standard vfork behaviour), or if it does run then vfork is behaving
    690 	 more like fork.  In either case we needn't worry about clobbering
    691 	 the child's copy of environ.  */
    692       environ = save_environ;
    693 
    694       if (in != STDIN_FILE_NO)
    695 	{
    696 	  if (close (in) < 0)
    697 	    {
    698 	      *err = errno;
    699 	      *errmsg = "close";
    700 	      return (pid_t) -1;
    701 	    }
    702 	}
    703       if (out != STDOUT_FILE_NO)
    704 	{
    705 	  if (close (out) < 0)
    706 	    {
    707 	      *err = errno;
    708 	      *errmsg = "close";
    709 	      return (pid_t) -1;
    710 	    }
    711 	}
    712       if (errdes != STDERR_FILE_NO)
    713 	{
    714 	  if (close (errdes) < 0)
    715 	    {
    716 	      *err = errno;
    717 	      *errmsg = "close";
    718 	      return (pid_t) -1;
    719 	    }
    720 	}
    721 
    722       return pid;
    723     }
    724 }
    725 #endif /* SPAWN */
    726 
    727 /* Wait for a child process to complete.  */
    728 
    729 static int
    730 pex_unix_wait (struct pex_obj *obj, pid_t pid, int *status,
    731 	       struct pex_time *time, int done, const char **errmsg,
    732 	       int *err)
    733 {
    734   /* If we are cleaning up when the caller didn't retrieve process
    735      status for some reason, encourage the process to go away.  */
    736   if (done)
    737     kill (pid, SIGTERM);
    738 
    739   if (pex_wait (obj, pid, status, time) < 0)
    740     {
    741       *err = errno;
    742       *errmsg = "wait";
    743       return -1;
    744     }
    745 
    746   return 0;
    747 }
    748 
    749 /* Create a pipe.  */
    750 
    751 static int
    752 pex_unix_pipe (struct pex_obj *obj ATTRIBUTE_UNUSED, int *p,
    753 	       int binary ATTRIBUTE_UNUSED)
    754 {
    755   return pipe (p);
    756 }
    757 
    758 /* Get a FILE pointer to read from a file descriptor.  */
    759 
    760 static FILE *
    761 pex_unix_fdopenr (struct pex_obj *obj ATTRIBUTE_UNUSED, int fd,
    762 		  int binary ATTRIBUTE_UNUSED)
    763 {
    764   return fdopen (fd, "r");
    765 }
    766 
    767 static FILE *
    768 pex_unix_fdopenw (struct pex_obj *obj ATTRIBUTE_UNUSED, int fd,
    769 		  int binary ATTRIBUTE_UNUSED)
    770 {
    771   if (fcntl (fd, F_SETFD, FD_CLOEXEC) < 0)
    772     return NULL;
    773   return fdopen (fd, "w");
    774 }
    775 
    776 static void
    777 pex_unix_cleanup (struct pex_obj *obj ATTRIBUTE_UNUSED)
    778 {
    779 #if !defined (HAVE_WAIT4) && !defined (HAVE_WAITPID)
    780   while (obj->sysdep != NULL)
    781     {
    782       struct status_list *this;
    783       struct status_list *next;
    784 
    785       this = (struct status_list *) obj->sysdep;
    786       next = this->next;
    787       free (this);
    788       obj->sysdep = (void *) next;
    789     }
    790 #endif
    791 }
    792