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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, 2015 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 #include "environ.h"
     27 
     28 #include <stdio.h>
     29 #include <signal.h>
     30 #include <errno.h>
     31 #ifdef NEED_DECLARATION_ERRNO
     32 extern int errno;
     33 #endif
     34 #ifdef HAVE_STDLIB_H
     35 #include <stdlib.h>
     36 #endif
     37 #ifdef HAVE_STRING_H
     38 #include <string.h>
     39 #endif
     40 #ifdef HAVE_UNISTD_H
     41 #include <unistd.h>
     42 #endif
     43 
     44 #include <sys/types.h>
     45 
     46 #ifdef HAVE_FCNTL_H
     47 #include <fcntl.h>
     48 #endif
     49 #ifdef HAVE_SYS_WAIT_H
     50 #include <sys/wait.h>
     51 #endif
     52 #ifdef HAVE_GETRUSAGE
     53 #include <sys/time.h>
     54 #include <sys/resource.h>
     55 #endif
     56 #ifdef HAVE_SYS_STAT_H
     57 #include <sys/stat.h>
     58 #endif
     59 #ifdef HAVE_PROCESS_H
     60 #include <process.h>
     61 #endif
     62 
     63 #ifdef vfork /* Autoconf may define this to fork for us. */
     64 # define VFORK_STRING "fork"
     65 #else
     66 # define VFORK_STRING "vfork"
     67 #endif
     68 #ifdef HAVE_VFORK_H
     69 #include <vfork.h>
     70 #endif
     71 #if defined(VMS) && defined (__LONG_POINTERS)
     72 #ifndef __CHAR_PTR32
     73 typedef char * __char_ptr32
     74 __attribute__ ((mode (SI)));
     75 #endif
     76 
     77 typedef __char_ptr32 *__char_ptr_char_ptr32
     78 __attribute__ ((mode (SI)));
     79 
     80 /* Return a 32 bit pointer to an array of 32 bit pointers
     81    given a 64 bit pointer to an array of 64 bit pointers.  */
     82 
     83 static __char_ptr_char_ptr32
     84 to_ptr32 (char **ptr64)
     85 {
     86   int argc;
     87   __char_ptr_char_ptr32 short_argv;
     88 
     89   /* Count number of arguments.  */
     90   for (argc = 0; ptr64[argc] != NULL; argc++)
     91     ;
     92 
     93   /* Reallocate argv with 32 bit pointers.  */
     94   short_argv = (__char_ptr_char_ptr32) decc$malloc
     95     (sizeof (__char_ptr32) * (argc + 1));
     96 
     97   for (argc = 0; ptr64[argc] != NULL; argc++)
     98     short_argv[argc] = (__char_ptr32) decc$strdup (ptr64[argc]);
     99 
    100   short_argv[argc] = (__char_ptr32) 0;
    101   return short_argv;
    102 
    103 }
    104 #else
    105 #define to_ptr32(argv) argv
    106 #endif
    107 
    108 /* File mode to use for private and world-readable files.  */
    109 
    110 #if defined (S_IRUSR) && defined (S_IWUSR) && defined (S_IRGRP) && defined (S_IWGRP) && defined (S_IROTH) && defined (S_IWOTH)
    111 #define PUBLIC_MODE  \
    112     (S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH)
    113 #else
    114 #define PUBLIC_MODE 0666
    115 #endif
    116 
    117 /* Get the exit status of a particular process, and optionally get the
    118    time that it took.  This is simple if we have wait4, slightly
    119    harder if we have waitpid, and is a pain if we only have wait.  */
    120 
    121 static pid_t pex_wait (struct pex_obj *, pid_t, int *, struct pex_time *);
    122 
    123 #ifdef HAVE_WAIT4
    124 
    125 static pid_t
    126 pex_wait (struct pex_obj *obj ATTRIBUTE_UNUSED, pid_t pid, int *status,
    127 	  struct pex_time *time)
    128 {
    129   pid_t ret;
    130   struct rusage r;
    131 
    132 #ifdef HAVE_WAITPID
    133   if (time == NULL)
    134     return waitpid (pid, status, 0);
    135 #endif
    136 
    137   ret = wait4 (pid, status, 0, &r);
    138 
    139   if (time != NULL)
    140     {
    141       time->user_seconds = r.ru_utime.tv_sec;
    142       time->user_microseconds= r.ru_utime.tv_usec;
    143       time->system_seconds = r.ru_stime.tv_sec;
    144       time->system_microseconds= r.ru_stime.tv_usec;
    145     }
    146 
    147   return ret;
    148 }
    149 
    150 #else /* ! defined (HAVE_WAIT4) */
    151 
    152 #ifdef HAVE_WAITPID
    153 
    154 #ifndef HAVE_GETRUSAGE
    155 
    156 static pid_t
    157 pex_wait (struct pex_obj *obj ATTRIBUTE_UNUSED, pid_t pid, int *status,
    158 	  struct pex_time *time)
    159 {
    160   if (time != NULL)
    161     memset (time, 0, sizeof (struct pex_time));
    162   return waitpid (pid, status, 0);
    163 }
    164 
    165 #else /* defined (HAVE_GETRUSAGE) */
    166 
    167 static pid_t
    168 pex_wait (struct pex_obj *obj ATTRIBUTE_UNUSED, pid_t pid, int *status,
    169 	  struct pex_time *time)
    170 {
    171   struct rusage r1, r2;
    172   pid_t ret;
    173 
    174   if (time == NULL)
    175     return waitpid (pid, status, 0);
    176 
    177   getrusage (RUSAGE_CHILDREN, &r1);
    178 
    179   ret = waitpid (pid, status, 0);
    180   if (ret < 0)
    181     return ret;
    182 
    183   getrusage (RUSAGE_CHILDREN, &r2);
    184 
    185   time->user_seconds = r2.ru_utime.tv_sec - r1.ru_utime.tv_sec;
    186   time->user_microseconds = r2.ru_utime.tv_usec - r1.ru_utime.tv_usec;
    187   if (r2.ru_utime.tv_usec < r1.ru_utime.tv_usec)
    188     {
    189       --time->user_seconds;
    190       time->user_microseconds += 1000000;
    191     }
    192 
    193   time->system_seconds = r2.ru_stime.tv_sec - r1.ru_stime.tv_sec;
    194   time->system_microseconds = r2.ru_stime.tv_usec - r1.ru_stime.tv_usec;
    195   if (r2.ru_stime.tv_usec < r1.ru_stime.tv_usec)
    196     {
    197       --time->system_seconds;
    198       time->system_microseconds += 1000000;
    199     }
    200 
    201   return ret;
    202 }
    203 
    204 #endif /* defined (HAVE_GETRUSAGE) */
    205 
    206 #else /* ! defined (HAVE_WAITPID) */
    207 
    208 struct status_list
    209 {
    210   struct status_list *next;
    211   pid_t pid;
    212   int status;
    213   struct pex_time time;
    214 };
    215 
    216 static pid_t
    217 pex_wait (struct pex_obj *obj, pid_t pid, int *status, struct pex_time *time)
    218 {
    219   struct status_list **pp;
    220 
    221   for (pp = (struct status_list **) &obj->sysdep;
    222        *pp != NULL;
    223        pp = &(*pp)->next)
    224     {
    225       if ((*pp)->pid == pid)
    226 	{
    227 	  struct status_list *p;
    228 
    229 	  p = *pp;
    230 	  *status = p->status;
    231 	  if (time != NULL)
    232 	    *time = p->time;
    233 	  *pp = p->next;
    234 	  free (p);
    235 	  return pid;
    236 	}
    237     }
    238 
    239   while (1)
    240     {
    241       pid_t cpid;
    242       struct status_list *psl;
    243       struct pex_time pt;
    244 #ifdef HAVE_GETRUSAGE
    245       struct rusage r1, r2;
    246 #endif
    247 
    248       if (time != NULL)
    249 	{
    250 #ifdef HAVE_GETRUSAGE
    251 	  getrusage (RUSAGE_CHILDREN, &r1);
    252 #else
    253 	  memset (&pt, 0, sizeof (struct pex_time));
    254 #endif
    255 	}
    256 
    257       cpid = wait (status);
    258 
    259 #ifdef HAVE_GETRUSAGE
    260       if (time != NULL && cpid >= 0)
    261 	{
    262 	  getrusage (RUSAGE_CHILDREN, &r2);
    263 
    264 	  pt.user_seconds = r2.ru_utime.tv_sec - r1.ru_utime.tv_sec;
    265 	  pt.user_microseconds = r2.ru_utime.tv_usec - r1.ru_utime.tv_usec;
    266 	  if (pt.user_microseconds < 0)
    267 	    {
    268 	      --pt.user_seconds;
    269 	      pt.user_microseconds += 1000000;
    270 	    }
    271 
    272 	  pt.system_seconds = r2.ru_stime.tv_sec - r1.ru_stime.tv_sec;
    273 	  pt.system_microseconds = r2.ru_stime.tv_usec - r1.ru_stime.tv_usec;
    274 	  if (pt.system_microseconds < 0)
    275 	    {
    276 	      --pt.system_seconds;
    277 	      pt.system_microseconds += 1000000;
    278 	    }
    279 	}
    280 #endif
    281 
    282       if (cpid < 0 || cpid == pid)
    283 	{
    284 	  if (time != NULL)
    285 	    *time = pt;
    286 	  return cpid;
    287 	}
    288 
    289       psl = XNEW (struct status_list);
    290       psl->pid = cpid;
    291       psl->status = *status;
    292       if (time != NULL)
    293 	psl->time = pt;
    294       psl->next = (struct status_list *) obj->sysdep;
    295       obj->sysdep = (void *) psl;
    296     }
    297 }
    298 
    299 #endif /* ! defined (HAVE_WAITPID) */
    300 #endif /* ! defined (HAVE_WAIT4) */
    301 
    302 static void pex_child_error (struct pex_obj *, const char *, const char *, int)
    303      ATTRIBUTE_NORETURN;
    304 static int pex_unix_open_read (struct pex_obj *, const char *, int);
    305 static int pex_unix_open_write (struct pex_obj *, const char *, int, int);
    306 static pid_t pex_unix_exec_child (struct pex_obj *, int, const char *,
    307 				 char * const *, char * const *,
    308 				 int, int, int, int,
    309 				 const char **, int *);
    310 static int pex_unix_close (struct pex_obj *, int);
    311 static int pex_unix_wait (struct pex_obj *, pid_t, int *, struct pex_time *,
    312 			  int, const char **, int *);
    313 static int pex_unix_pipe (struct pex_obj *, int *, int);
    314 static FILE *pex_unix_fdopenr (struct pex_obj *, int, int);
    315 static FILE *pex_unix_fdopenw (struct pex_obj *, int, int);
    316 static void pex_unix_cleanup (struct pex_obj *);
    317 
    318 /* The list of functions we pass to the common routines.  */
    319 
    320 const struct pex_funcs funcs =
    321 {
    322   pex_unix_open_read,
    323   pex_unix_open_write,
    324   pex_unix_exec_child,
    325   pex_unix_close,
    326   pex_unix_wait,
    327   pex_unix_pipe,
    328   pex_unix_fdopenr,
    329   pex_unix_fdopenw,
    330   pex_unix_cleanup
    331 };
    332 
    333 /* Return a newly initialized pex_obj structure.  */
    334 
    335 struct pex_obj *
    336 pex_init (int flags, const char *pname, const char *tempbase)
    337 {
    338   return pex_init_common (flags, pname, tempbase, &funcs);
    339 }
    340 
    341 /* Open a file for reading.  */
    342 
    343 static int
    344 pex_unix_open_read (struct pex_obj *obj ATTRIBUTE_UNUSED, const char *name,
    345 		    int binary ATTRIBUTE_UNUSED)
    346 {
    347   return open (name, O_RDONLY);
    348 }
    349 
    350 /* Open a file for writing.  */
    351 
    352 static int
    353 pex_unix_open_write (struct pex_obj *obj ATTRIBUTE_UNUSED, const char *name,
    354 		     int binary ATTRIBUTE_UNUSED, int append)
    355 {
    356   /* Note that we can't use O_EXCL here because gcc may have already
    357      created the temporary file via make_temp_file.  */
    358   return open (name, O_WRONLY | O_CREAT
    359 		     | (append ? O_APPEND : O_TRUNC), PUBLIC_MODE);
    360 }
    361 
    362 /* Close a file.  */
    363 
    364 static int
    365 pex_unix_close (struct pex_obj *obj ATTRIBUTE_UNUSED, int fd)
    366 {
    367   return close (fd);
    368 }
    369 
    370 /* Report an error from a child process.  We don't use stdio routines,
    371    because we might be here due to a vfork call.  */
    372 
    373 static void
    374 pex_child_error (struct pex_obj *obj, const char *executable,
    375 		 const char *errmsg, int err)
    376 {
    377   int retval = 0;
    378 #define writeerr(s) retval |= (write (STDERR_FILE_NO, s, strlen (s)) < 0)
    379   writeerr (obj->pname);
    380   writeerr (": error trying to exec '");
    381   writeerr (executable);
    382   writeerr ("': ");
    383   writeerr (errmsg);
    384   writeerr (": ");
    385   writeerr (xstrerror (err));
    386   writeerr ("\n");
    387 #undef writeerr
    388   /* Exit with -2 if the error output failed, too.  */
    389   _exit (retval == 0 ? -1 : -2);
    390 }
    391 
    392 /* Execute a child.  */
    393 
    394 #if defined(HAVE_SPAWNVE) && defined(HAVE_SPAWNVPE)
    395 /* Implementation of pex->exec_child using the Cygwin spawn operation.  */
    396 
    397 /* Subroutine of pex_unix_exec_child.  Move OLD_FD to a new file descriptor
    398    to be stored in *PNEW_FD, save the flags in *PFLAGS, and arrange for the
    399    saved copy to be close-on-exec.  Move CHILD_FD into OLD_FD.  If CHILD_FD
    400    is -1, OLD_FD is to be closed.  Return -1 on error.  */
    401 
    402 static int
    403 save_and_install_fd(int *pnew_fd, int *pflags, int old_fd, int child_fd)
    404 {
    405   int new_fd, flags;
    406 
    407   flags = fcntl (old_fd, F_GETFD);
    408 
    409   /* If we could not retrieve the flags, then OLD_FD was not open.  */
    410   if (flags < 0)
    411     {
    412       new_fd = -1, flags = 0;
    413       if (child_fd >= 0 && dup2 (child_fd, old_fd) < 0)
    414 	return -1;
    415     }
    416   /* If we wish to close OLD_FD, just mark it CLOEXEC.  */
    417   else if (child_fd == -1)
    418     {
    419       new_fd = old_fd;
    420       if ((flags & FD_CLOEXEC) == 0 && fcntl (old_fd, F_SETFD, FD_CLOEXEC) < 0)
    421 	return -1;
    422     }
    423   /* Otherwise we need to save a copy of OLD_FD before installing CHILD_FD.  */
    424   else
    425     {
    426 #ifdef F_DUPFD_CLOEXEC
    427       new_fd = fcntl (old_fd, F_DUPFD_CLOEXEC, 3);
    428       if (new_fd < 0)
    429 	return -1;
    430 #else
    431       /* Prefer F_DUPFD over dup in order to avoid getting a new fd
    432 	 in the range 0-2, right where a new stderr fd might get put.  */
    433       new_fd = fcntl (old_fd, F_DUPFD, 3);
    434       if (new_fd < 0)
    435 	return -1;
    436       if (fcntl (new_fd, F_SETFD, FD_CLOEXEC) < 0)
    437 	return -1;
    438 #endif
    439       if (dup2 (child_fd, old_fd) < 0)
    440 	return -1;
    441     }
    442 
    443   *pflags = flags;
    444   if (pnew_fd)
    445     *pnew_fd = new_fd;
    446   else if (new_fd != old_fd)
    447     abort ();
    448 
    449   return 0;
    450 }
    451 
    452 /* Subroutine of pex_unix_exec_child.  Move SAVE_FD back to OLD_FD
    453    restoring FLAGS.  If SAVE_FD < 0, OLD_FD is to be closed.  */
    454 
    455 static int
    456 restore_fd(int old_fd, int save_fd, int flags)
    457 {
    458   /* For SAVE_FD < 0, all we have to do is restore the
    459      "closed-ness" of the original.  */
    460   if (save_fd < 0)
    461     return close (old_fd);
    462 
    463   /* For SAVE_FD == OLD_FD, all we have to do is restore the
    464      original setting of the CLOEXEC flag.  */
    465   if (save_fd == old_fd)
    466     {
    467       if (flags & FD_CLOEXEC)
    468 	return 0;
    469       return fcntl (old_fd, F_SETFD, flags);
    470     }
    471 
    472   /* Otherwise we have to move the descriptor back, restore the flags,
    473      and close the saved copy.  */
    474 #ifdef HAVE_DUP3
    475   if (flags == FD_CLOEXEC)
    476     {
    477       if (dup3 (save_fd, old_fd, O_CLOEXEC) < 0)
    478 	return -1;
    479     }
    480   else
    481 #endif
    482     {
    483       if (dup2 (save_fd, old_fd) < 0)
    484 	return -1;
    485       if (flags != 0 && fcntl (old_fd, F_SETFD, flags) < 0)
    486 	return -1;
    487     }
    488   return close (save_fd);
    489 }
    490 
    491 static pid_t
    492 pex_unix_exec_child (struct pex_obj *obj ATTRIBUTE_UNUSED,
    493 		     int flags, const char *executable,
    494 		     char * const * argv, char * const * env,
    495                      int in, int out, int errdes, int toclose,
    496 		     const char **errmsg, int *err)
    497 {
    498   int fl_in = 0, fl_out = 0, fl_err = 0, fl_tc = 0;
    499   int save_in = -1, save_out = -1, save_err = -1;
    500   int max, retries;
    501   pid_t pid;
    502 
    503   if (flags & PEX_STDERR_TO_STDOUT)
    504     errdes = out;
    505 
    506   /* We need the three standard file descriptors to be set up as for
    507      the child before we perform the spawn.  The file descriptors for
    508      the parent need to be moved and marked for close-on-exec.  */
    509   if (in != STDIN_FILE_NO
    510       && save_and_install_fd (&save_in, &fl_in, STDIN_FILE_NO, in) < 0)
    511     goto error_dup2;
    512   if (out != STDOUT_FILE_NO
    513       && save_and_install_fd (&save_out, &fl_out, STDOUT_FILE_NO, out) < 0)
    514     goto error_dup2;
    515   if (errdes != STDERR_FILE_NO
    516       && save_and_install_fd (&save_err, &fl_err, STDERR_FILE_NO, errdes) < 0)
    517     goto error_dup2;
    518   if (toclose >= 0
    519       && save_and_install_fd (NULL, &fl_tc, toclose, -1) < 0)
    520     goto error_dup2;
    521 
    522   /* Now that we've moved the file descriptors for the child into place,
    523      close the originals.  Be careful not to close any of the standard
    524      file descriptors that we just set up.  */
    525   max = -1;
    526   if (errdes >= 0)
    527     max = STDERR_FILE_NO;
    528   else if (out >= 0)
    529     max = STDOUT_FILE_NO;
    530   else if (in >= 0)
    531     max = STDIN_FILE_NO;
    532   if (in > max)
    533     close (in);
    534   if (out > max)
    535     close (out);
    536   if (errdes > max && errdes != out)
    537     close (errdes);
    538 
    539   /* If we were not given an environment, use the global environment.  */
    540   if (env == NULL)
    541     env = environ;
    542 
    543   /* Launch the program.  If we get EAGAIN (normally out of pid's), try
    544      again a few times with increasing backoff times.  */
    545   retries = 0;
    546   while (1)
    547     {
    548       typedef const char * const *cc_cp;
    549 
    550       if (flags & PEX_SEARCH)
    551 	pid = spawnvpe (_P_NOWAITO, executable, (cc_cp)argv, (cc_cp)env);
    552       else
    553 	pid = spawnve (_P_NOWAITO, executable, (cc_cp)argv, (cc_cp)env);
    554 
    555       if (pid > 0)
    556 	break;
    557 
    558       *err = errno;
    559       *errmsg = "spawn";
    560       if (errno != EAGAIN || ++retries == 4)
    561 	return (pid_t) -1;
    562       sleep (1 << retries);
    563     }
    564 
    565   /* Success.  Restore the parent's file descriptors that we saved above.  */
    566   if (toclose >= 0
    567       && restore_fd (toclose, toclose, fl_tc) < 0)
    568     goto error_dup2;
    569   if (in != STDIN_FILE_NO
    570       && restore_fd (STDIN_FILE_NO, save_in, fl_in) < 0)
    571     goto error_dup2;
    572   if (out != STDOUT_FILE_NO
    573       && restore_fd (STDOUT_FILE_NO, save_out, fl_out) < 0)
    574     goto error_dup2;
    575   if (errdes != STDERR_FILE_NO
    576       && restore_fd (STDERR_FILE_NO, save_err, fl_err) < 0)
    577     goto error_dup2;
    578 
    579   return pid;
    580 
    581  error_dup2:
    582   *err = errno;
    583   *errmsg = "dup2";
    584   return (pid_t) -1;
    585 }
    586 
    587 #else
    588 /* Implementation of pex->exec_child using standard vfork + exec.  */
    589 
    590 static pid_t
    591 pex_unix_exec_child (struct pex_obj *obj, int flags, const char *executable,
    592 		     char * const * argv, char * const * env,
    593                      int in, int out, int errdes,
    594 		     int toclose, const char **errmsg, int *err)
    595 {
    596   pid_t pid;
    597 
    598   /* We declare these to be volatile to avoid warnings from gcc about
    599      them being clobbered by vfork.  */
    600   volatile int sleep_interval;
    601   volatile int retries;
    602 
    603   /* We vfork and then set environ in the child before calling execvp.
    604      This clobbers the parent's environ so we need to restore it.
    605      It would be nice to use one of the exec* functions that takes an
    606      environment as a parameter, but that may have portability issues.  */
    607   char **save_environ = environ;
    608 
    609   sleep_interval = 1;
    610   pid = -1;
    611   for (retries = 0; retries < 4; ++retries)
    612     {
    613       pid = vfork ();
    614       if (pid >= 0)
    615 	break;
    616       sleep (sleep_interval);
    617       sleep_interval *= 2;
    618     }
    619 
    620   switch (pid)
    621     {
    622     case -1:
    623       *err = errno;
    624       *errmsg = VFORK_STRING;
    625       return (pid_t) -1;
    626 
    627     case 0:
    628       /* Child process.  */
    629       if (in != STDIN_FILE_NO)
    630 	{
    631 	  if (dup2 (in, STDIN_FILE_NO) < 0)
    632 	    pex_child_error (obj, executable, "dup2", errno);
    633 	  if (close (in) < 0)
    634 	    pex_child_error (obj, executable, "close", errno);
    635 	}
    636       if (out != STDOUT_FILE_NO)
    637 	{
    638 	  if (dup2 (out, STDOUT_FILE_NO) < 0)
    639 	    pex_child_error (obj, executable, "dup2", errno);
    640 	  if (close (out) < 0)
    641 	    pex_child_error (obj, executable, "close", errno);
    642 	}
    643       if (errdes != STDERR_FILE_NO)
    644 	{
    645 	  if (dup2 (errdes, STDERR_FILE_NO) < 0)
    646 	    pex_child_error (obj, executable, "dup2", errno);
    647 	  if (close (errdes) < 0)
    648 	    pex_child_error (obj, executable, "close", errno);
    649 	}
    650       if (toclose >= 0)
    651 	{
    652 	  if (close (toclose) < 0)
    653 	    pex_child_error (obj, executable, "close", errno);
    654 	}
    655       if ((flags & PEX_STDERR_TO_STDOUT) != 0)
    656 	{
    657 	  if (dup2 (STDOUT_FILE_NO, STDERR_FILE_NO) < 0)
    658 	    pex_child_error (obj, executable, "dup2", errno);
    659 	}
    660 
    661       if (env)
    662 	{
    663 	  /* NOTE: In a standard vfork implementation this clobbers the
    664 	     parent's copy of environ "too" (in reality there's only one copy).
    665 	     This is ok as we restore it below.  */
    666 	  environ = (char**) env;
    667 	}
    668 
    669       if ((flags & PEX_SEARCH) != 0)
    670 	{
    671 	  execvp (executable, to_ptr32 (argv));
    672 	  pex_child_error (obj, executable, "execvp", errno);
    673 	}
    674       else
    675 	{
    676 	  execv (executable, to_ptr32 (argv));
    677 	  pex_child_error (obj, executable, "execv", errno);
    678 	}
    679 
    680       /* NOTREACHED */
    681       return (pid_t) -1;
    682 
    683     default:
    684       /* Parent process.  */
    685 
    686       /* Restore environ.
    687 	 Note that the parent either doesn't run until the child execs/exits
    688 	 (standard vfork behaviour), or if it does run then vfork is behaving
    689 	 more like fork.  In either case we needn't worry about clobbering
    690 	 the child's copy of environ.  */
    691       environ = save_environ;
    692 
    693       if (in != STDIN_FILE_NO)
    694 	{
    695 	  if (close (in) < 0)
    696 	    {
    697 	      *err = errno;
    698 	      *errmsg = "close";
    699 	      return (pid_t) -1;
    700 	    }
    701 	}
    702       if (out != STDOUT_FILE_NO)
    703 	{
    704 	  if (close (out) < 0)
    705 	    {
    706 	      *err = errno;
    707 	      *errmsg = "close";
    708 	      return (pid_t) -1;
    709 	    }
    710 	}
    711       if (errdes != STDERR_FILE_NO)
    712 	{
    713 	  if (close (errdes) < 0)
    714 	    {
    715 	      *err = errno;
    716 	      *errmsg = "close";
    717 	      return (pid_t) -1;
    718 	    }
    719 	}
    720 
    721       return pid;
    722     }
    723 }
    724 #endif /* SPAWN */
    725 
    726 /* Wait for a child process to complete.  */
    727 
    728 static int
    729 pex_unix_wait (struct pex_obj *obj, pid_t pid, int *status,
    730 	       struct pex_time *time, int done, const char **errmsg,
    731 	       int *err)
    732 {
    733   /* If we are cleaning up when the caller didn't retrieve process
    734      status for some reason, encourage the process to go away.  */
    735   if (done)
    736     kill (pid, SIGTERM);
    737 
    738   if (pex_wait (obj, pid, status, time) < 0)
    739     {
    740       *err = errno;
    741       *errmsg = "wait";
    742       return -1;
    743     }
    744 
    745   return 0;
    746 }
    747 
    748 /* Create a pipe.  */
    749 
    750 static int
    751 pex_unix_pipe (struct pex_obj *obj ATTRIBUTE_UNUSED, int *p,
    752 	       int binary ATTRIBUTE_UNUSED)
    753 {
    754   return pipe (p);
    755 }
    756 
    757 /* Get a FILE pointer to read from a file descriptor.  */
    758 
    759 static FILE *
    760 pex_unix_fdopenr (struct pex_obj *obj ATTRIBUTE_UNUSED, int fd,
    761 		  int binary ATTRIBUTE_UNUSED)
    762 {
    763   return fdopen (fd, "r");
    764 }
    765 
    766 static FILE *
    767 pex_unix_fdopenw (struct pex_obj *obj ATTRIBUTE_UNUSED, int fd,
    768 		  int binary ATTRIBUTE_UNUSED)
    769 {
    770   if (fcntl (fd, F_SETFD, FD_CLOEXEC) < 0)
    771     return NULL;
    772   return fdopen (fd, "w");
    773 }
    774 
    775 static void
    776 pex_unix_cleanup (struct pex_obj *obj ATTRIBUTE_UNUSED)
    777 {
    778 #if !defined (HAVE_WAIT4) && !defined (HAVE_WAITPID)
    779   while (obj->sysdep != NULL)
    780     {
    781       struct status_list *this;
    782       struct status_list *next;
    783 
    784       this = (struct status_list *) obj->sysdep;
    785       next = this->next;
    786       free (this);
    787       obj->sysdep = (void *) next;
    788     }
    789 #endif
    790 }
    791