Fix some minor races in hosts lacking mkostemp.

[bpt/emacs.git] / src / callproc.c

/* Synchronous subprocess invocation for GNU Emacs.
   Copyright (C) 1985-1988, 1993-1995, 1999-2013
                 Free Software Foundation, Inc.

This file is part of GNU Emacs.

GNU Emacs 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.

GNU Emacs 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 GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */


#include <config.h>
#include <errno.h>
#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>

#include <sys/file.h>
#include <fcntl.h>

#include "lisp.h"

#ifdef WINDOWSNT
#define NOMINMAX
#include <sys/socket.h> /* for fcntl */
#include <windows.h>
#include "w32.h"
#define _P_NOWAIT 1     /* from process.h */
#endif

#ifdef MSDOS    /* Demacs 1.1.1 91/10/16 HIRANO Satoshi */
#include <sys/stat.h>
#include <sys/param.h>
#endif /* MSDOS */

#include "commands.h"
#include "character.h"
#include "buffer.h"
#include "ccl.h"
#include "coding.h"
#include "composite.h"
#include <epaths.h>
#include "process.h"
#include "syssignal.h"
#include "systty.h"
#include "syswait.h"
#include "blockinput.h"
#include "frame.h"
#include "termhooks.h"

#ifdef MSDOS
#include "msdos.h"
#endif

#ifdef HAVE_NS
#include "nsterm.h"
#endif

/* Pattern used by call-process-region to make temp files.  */
static Lisp_Object Vtemp_file_name_pattern;

/* The next two variables are valid only while record-unwind-protect
   is in place during call-process for a synchronous subprocess.  At
   other times, their contents are irrelevant.  Doing this via static
   C variables is more convenient than putting them into the arguments
   of record-unwind-protect, as they need to be updated at randomish
   times in the code, and Lisp cannot always store these values as
   Emacs integers.  It's safe to use static variables here, as the
   code is never invoked reentrantly.  */

/* If nonzero, a process-ID that has not been reaped.  */
static pid_t synch_process_pid;

/* If nonnegative, a file descriptor that has not been closed.  */
static int synch_process_fd;
\f
/* Block SIGCHLD.  */

void
block_child_signal (void)
{
  sigset_t blocked;
  sigemptyset (&blocked);
  sigaddset (&blocked, SIGCHLD);
  pthread_sigmask (SIG_BLOCK, &blocked, 0);
}

/* Unblock SIGCHLD.  */

void
unblock_child_signal (void)
{
  pthread_sigmask (SIG_SETMASK, &empty_mask, 0);
}

/* If P is reapable, record it as a deleted process and kill it.
   Do this in a critical section.  Unless PID is wedged it will be
   reaped on receipt of the first SIGCHLD after the critical section.  */

void
record_kill_process (struct Lisp_Process *p)
{
  block_child_signal ();

  if (p->alive)
    {
      p->alive = 0;
      record_deleted_pid (p->pid);
      kill (- p->pid, SIGKILL);
    }

  unblock_child_signal ();
}

/* Clean up when exiting call_process_cleanup.  */

static void
call_process_kill (void)
{
  if (synch_process_fd >= 0)
    emacs_close (synch_process_fd);

  if (synch_process_pid)
    {
      struct Lisp_Process proc;
      proc.alive = 1;
      proc.pid = synch_process_pid;
      record_kill_process (&proc);
    }
}

/* Clean up when exiting Fcall_process.
   On MSDOS, delete the temporary file on any kind of termination.
   On Unix, kill the process and any children on termination by signal.  */

static void
call_process_cleanup (Lisp_Object arg)
{
#ifdef MSDOS
  Lisp_Object buffer = Fcar (arg);
  Lisp_Object file = Fcdr (arg);
#else
  Lisp_Object buffer = arg;
#endif

  Fset_buffer (buffer);

#ifndef MSDOS
  /* If the process still exists, kill its process group.  */
  if (synch_process_pid)
    {
      ptrdiff_t count = SPECPDL_INDEX ();
      kill (-synch_process_pid, SIGINT);
      record_unwind_protect_void (call_process_kill);
      message1 ("Waiting for process to die...(type C-g again to kill it instantly)");
      immediate_quit = 1;
      QUIT;
      wait_for_termination (synch_process_pid, 0, 1);
      synch_process_pid = 0;
      immediate_quit = 0;
      specpdl_ptr = specpdl + count; /* Discard the unwind protect.  */
      message1 ("Waiting for process to die...done");
    }
#endif

  if (synch_process_fd >= 0)
    emacs_close (synch_process_fd);

#ifdef MSDOS
  /* FILE is "" when we didn't actually create a temporary file in
     call-process.  */
  if (!(strcmp (SDATA (file), NULL_DEVICE) == 0 || SREF (file, 0) == '\0'))
    unlink (SDATA (file));
#endif
}

#ifdef DOS_NT
static mode_t const default_output_mode = S_IREAD | S_IWRITE;
#else
static mode_t const default_output_mode = 0666;
#endif

DEFUN ("call-process", Fcall_process, Scall_process, 1, MANY, 0,
       doc: /* Call PROGRAM synchronously in separate process.
The remaining arguments are optional.
The program's input comes from file INFILE (nil means `/dev/null').
Insert output in DESTINATION before point; t means current buffer; nil for DESTINATION
 means discard it; 0 means discard and don't wait; and `(:file FILE)', where
 FILE is a file name string, means that it should be written to that file
 \(if the file already exists it is overwritten).
DESTINATION can also have the form (REAL-BUFFER STDERR-FILE); in that case,
REAL-BUFFER says what to do with standard output, as above,
while STDERR-FILE says what to do with standard error in the child.
STDERR-FILE may be nil (discard standard error output),
t (mix it with ordinary output), or a file name string.

Fourth arg DISPLAY non-nil means redisplay buffer as output is inserted.
Remaining arguments are strings passed as command arguments to PROGRAM.

If executable PROGRAM can't be found as an executable, `call-process'
signals a Lisp error.  `call-process' reports errors in execution of
the program only through its return and output.

If DESTINATION is 0, `call-process' returns immediately with value nil.
Otherwise it waits for PROGRAM to terminate
and returns a numeric exit status or a signal description string.
If you quit, the process is killed with SIGINT, or SIGKILL if you quit again.

usage: (call-process PROGRAM &optional INFILE DESTINATION DISPLAY &rest ARGS)  */)
  (ptrdiff_t nargs, Lisp_Object *args)
{
  Lisp_Object infile, buffer, current_dir, path;
  bool display_p;
  int fd0, fd1, filefd;
  int status;
  ptrdiff_t count = SPECPDL_INDEX ();
  USE_SAFE_ALLOCA;

  char **new_argv;
  /* File to use for stderr in the child.
     t means use same as standard output.  */
  Lisp_Object error_file;
  Lisp_Object output_file = Qnil;
#ifdef MSDOS    /* Demacs 1.1.1 91/10/16 HIRANO Satoshi */
  char *outf, *tempfile = NULL;
  int outfilefd;
  int pid;
#else
  pid_t pid;
#endif
  int child_errno;
  int fd_output = -1;
  struct coding_system process_coding; /* coding-system of process output */
  struct coding_system argument_coding; /* coding-system of arguments */
  /* Set to the return value of Ffind_operation_coding_system.  */
  Lisp_Object coding_systems;
  bool output_to_buffer = 1;

  /* Qt denotes that Ffind_operation_coding_system is not yet called.  */
  coding_systems = Qt;

  CHECK_STRING (args[0]);

  error_file = Qt;

#ifndef subprocesses
  /* Without asynchronous processes we cannot have BUFFER == 0.  */
  if (nargs >= 3
      && (INTEGERP (CONSP (args[2]) ? XCAR (args[2]) : args[2])))
    error ("Operating system cannot handle asynchronous subprocesses");
#endif /* subprocesses */

  /* Decide the coding-system for giving arguments.  */
  {
    Lisp_Object val, *args2;
    ptrdiff_t i;

    /* If arguments are supplied, we may have to encode them.  */
    if (nargs >= 5)
      {
        bool must_encode = 0;
        Lisp_Object coding_attrs;

        for (i = 4; i < nargs; i++)
          CHECK_STRING (args[i]);

        for (i = 4; i < nargs; i++)
          if (STRING_MULTIBYTE (args[i]))
            must_encode = 1;

        if (!NILP (Vcoding_system_for_write))
          val = Vcoding_system_for_write;
        else if (! must_encode)
          val = Qraw_text;
        else
          {
            SAFE_NALLOCA (args2, 1, nargs + 1);
            args2[0] = Qcall_process;
            for (i = 0; i < nargs; i++) args2[i + 1] = args[i];
            coding_systems = Ffind_operation_coding_system (nargs + 1, args2);
            val = CONSP (coding_systems) ? XCDR (coding_systems) : Qnil;
          }
        val = complement_process_encoding_system (val);
        setup_coding_system (Fcheck_coding_system (val), &argument_coding);
        coding_attrs = CODING_ID_ATTRS (argument_coding.id);
        if (NILP (CODING_ATTR_ASCII_COMPAT (coding_attrs)))
          {
            /* We should not use an ASCII incompatible coding system.  */
            val = raw_text_coding_system (val);
            setup_coding_system (val, &argument_coding);
          }
      }
  }

  if (nargs >= 2 && ! NILP (args[1]))
    {
      infile = Fexpand_file_name (args[1], BVAR (current_buffer, directory));
      CHECK_STRING (infile);
    }
  else
    infile = build_string (NULL_DEVICE);

  if (nargs >= 3)
    {
      buffer = args[2];

      /* If BUFFER is a list, its meaning is (BUFFER-FOR-STDOUT
         FILE-FOR-STDERR), unless the first element is :file, in which case see
         the next paragraph. */
      if (CONSP (buffer)
          && (! SYMBOLP (XCAR (buffer))
              || strcmp (SSDATA (SYMBOL_NAME (XCAR (buffer))), ":file")))
        {
          if (CONSP (XCDR (buffer)))
            {
              Lisp_Object stderr_file;
              stderr_file = XCAR (XCDR (buffer));

              if (NILP (stderr_file) || EQ (Qt, stderr_file))
                error_file = stderr_file;
              else
                error_file = Fexpand_file_name (stderr_file, Qnil);
            }

          buffer = XCAR (buffer);
        }

      /* If the buffer is (still) a list, it might be a (:file "file") spec. */
      if (CONSP (buffer)
          && SYMBOLP (XCAR (buffer))
          && ! strcmp (SSDATA (SYMBOL_NAME (XCAR (buffer))), ":file"))
        {
          output_file = Fexpand_file_name (XCAR (XCDR (buffer)),
                                           BVAR (current_buffer, directory));
          CHECK_STRING (output_file);
          buffer = Qnil;
        }

      if (!(EQ (buffer, Qnil)
            || EQ (buffer, Qt)
            || INTEGERP (buffer)))
        {
          Lisp_Object spec_buffer;
          spec_buffer = buffer;
          buffer = Fget_buffer_create (buffer);
          /* Mention the buffer name for a better error message.  */
          if (NILP (buffer))
            CHECK_BUFFER (spec_buffer);
          CHECK_BUFFER (buffer);
        }
    }
  else
    buffer = Qnil;

  /* Make sure that the child will be able to chdir to the current
     buffer's current directory, or its unhandled equivalent.  We
     can't just have the child check for an error when it does the
     chdir, since it's in a vfork.

     We have to GCPRO around this because Fexpand_file_name,
     Funhandled_file_name_directory, and Ffile_accessible_directory_p
     might call a file name handling function.  The argument list is
     protected by the caller, so all we really have to worry about is
     buffer.  */
  {
    struct gcpro gcpro1, gcpro2, gcpro3, gcpro4, gcpro5;

    current_dir = BVAR (current_buffer, directory);

    GCPRO5 (infile, buffer, current_dir, error_file, output_file);

    current_dir = Funhandled_file_name_directory (current_dir);
    if (NILP (current_dir))
      /* If the file name handler says that current_dir is unreachable, use
         a sensible default. */
      current_dir = build_string ("~/");
    current_dir = expand_and_dir_to_file (current_dir, Qnil);
    current_dir = Ffile_name_as_directory (current_dir);

    if (NILP (Ffile_accessible_directory_p (current_dir)))
      report_file_error ("Setting current directory",
                         BVAR (current_buffer, directory));

    if (STRING_MULTIBYTE (infile))
      infile = ENCODE_FILE (infile);
    if (STRING_MULTIBYTE (current_dir))
      current_dir = ENCODE_FILE (current_dir);
    if (STRINGP (error_file) && STRING_MULTIBYTE (error_file))
      error_file = ENCODE_FILE (error_file);
    if (STRINGP (output_file) && STRING_MULTIBYTE (output_file))
      output_file = ENCODE_FILE (output_file);
    UNGCPRO;
  }

  display_p = INTERACTIVE && nargs >= 4 && !NILP (args[3]);

  filefd = emacs_open (SSDATA (infile), O_RDONLY, 0);
  if (filefd < 0)
    {
      int open_errno = errno;
      report_file_errno ("Opening process input file", DECODE_FILE (infile),
                         open_errno);
    }

  if (STRINGP (output_file))
    {
      fd_output = emacs_open (SSDATA (output_file),
                              O_WRONLY | O_CREAT | O_TRUNC | O_TEXT,
                              default_output_mode);
      if (fd_output < 0)
        {
          int open_errno = errno;
          output_file = DECODE_FILE (output_file);
          report_file_errno ("Opening process output file",
                             output_file, open_errno);
        }
      if (STRINGP (error_file) || NILP (error_file))
        output_to_buffer = 0;
    }

  /* Search for program; barf if not found.  */
  {
    struct gcpro gcpro1, gcpro2, gcpro3, gcpro4;
    int ok;

    GCPRO4 (infile, buffer, current_dir, error_file);
    ok = openp (Vexec_path, args[0], Vexec_suffixes, &path, make_number (X_OK));
    UNGCPRO;
    if (ok < 0)
      {
        int openp_errno = errno;
        emacs_close (filefd);
        report_file_errno ("Searching for program", args[0], openp_errno);
      }
  }

  /* If program file name starts with /: for quoting a magic name,
     discard that.  */
  if (SBYTES (path) > 2 && SREF (path, 0) == '/'
      && SREF (path, 1) == ':')
    path = Fsubstring (path, make_number (2), Qnil);

  new_argv = SAFE_ALLOCA ((nargs > 4 ? nargs - 2 : 2) * sizeof *new_argv);

  {
    struct gcpro gcpro1, gcpro2, gcpro3, gcpro4, gcpro5;

    GCPRO5 (infile, buffer, current_dir, path, error_file);
    if (nargs > 4)
      {
        ptrdiff_t i;

        argument_coding.dst_multibyte = 0;
        for (i = 4; i < nargs; i++)
          {
            argument_coding.src_multibyte = STRING_MULTIBYTE (args[i]);
            if (CODING_REQUIRE_ENCODING (&argument_coding))
              /* We must encode this argument.  */
              args[i] = encode_coding_string (&argument_coding, args[i], 1);
          }
        for (i = 4; i < nargs; i++)
          new_argv[i - 3] = SSDATA (args[i]);
        new_argv[i - 3] = 0;
      }
    else
      new_argv[1] = 0;
    if (STRING_MULTIBYTE (path))
      path = ENCODE_FILE (path);
    new_argv[0] = SSDATA (path);
    UNGCPRO;
  }

#ifdef MSDOS /* MW, July 1993 */

  /* If we're redirecting STDOUT to a file, that file is already open
     on fd_output.  */
  if (fd_output < 0)
    {
      if ((outf = egetenv ("TMPDIR")))
        strcpy (tempfile = alloca (strlen (outf) + 20), outf);
      else
        {
          tempfile = alloca (20);
          *tempfile = '\0';
        }
      dostounix_filename (tempfile, 0);
      if (*tempfile == '\0' || tempfile[strlen (tempfile) - 1] != '/')
        strcat (tempfile, "/");
      strcat (tempfile, "detmp.XXX");
      mktemp (tempfile);
      outfilefd = emacs_open (tempfile, O_WRONLY | O_CREAT | O_TRUNC,
                              S_IREAD | S_IWRITE);
      if (outfilefd < 0)
        {
          int open_errno = errno;
          emacs_close (filefd);
          report_file_errno ("Opening process output file",
                             build_string (tempfile), open_errno);
        }
    }
  else
    outfilefd = fd_output;
  fd0 = filefd;
  fd1 = outfilefd;
#endif /* MSDOS */

  if (INTEGERP (buffer))
    {
      fd0 = -1;
      fd1 = emacs_open (NULL_DEVICE, O_WRONLY, 0);
    }
  else
    {
#ifndef MSDOS
      int fd[2];
      if (emacs_pipe (fd) != 0)
        {
          int pipe_errno = errno;
          emacs_close (filefd);
          report_file_errno ("Creating process pipe", Qnil, pipe_errno);
        }
      fd0 = fd[0];
      fd1 = fd[1];
#endif
    }

  {
    int fd_error = fd1;

    if (fd_output >= 0)
      fd1 = fd_output;

    if (NILP (error_file))
      fd_error = emacs_open (NULL_DEVICE, O_WRONLY, 0);
    else if (STRINGP (error_file))
      fd_error = emacs_open (SSDATA (error_file),
                             O_WRONLY | O_CREAT | O_TRUNC | O_TEXT,
                             default_output_mode);

    if (fd_error < 0)
      {
        int open_errno = errno;
        emacs_close (filefd);
        if (fd0 != filefd)
          emacs_close (fd0);
        if (fd1 >= 0)
          emacs_close (fd1);
#ifdef MSDOS
        unlink (tempfile);
#endif
        if (NILP (error_file))
          error_file = build_string (NULL_DEVICE);
        else if (STRINGP (error_file))
          error_file = DECODE_FILE (error_file);
        report_file_errno ("Cannot redirect stderr", error_file, open_errno);
      }

#ifdef MSDOS /* MW, July 1993 */
    /* Note that on MSDOS `child_setup' actually returns the child process
       exit status, not its PID, so assign it to status below.  */
    pid = child_setup (filefd, outfilefd, fd_error, new_argv, 0, current_dir);
    child_errno = errno;

    emacs_close (outfilefd);
    if (fd_error != outfilefd)
      emacs_close (fd_error);
    if (pid < 0)
      {
        synchronize_system_messages_locale ();
        return
          code_convert_string_norecord (build_string (strerror (child_errno)),
                                        Vlocale_coding_system, 0);
      }
    status = pid;
    fd1 = -1; /* No harm in closing that one!  */
    if (tempfile)
      {
        /* Since CRLF is converted to LF within `decode_coding', we
           can always open a file with binary mode.  */
        fd0 = emacs_open (tempfile, O_RDONLY | O_BINARY, 0);
        if (fd0 < 0)
          {
            int open_errno = errno;
            unlink (tempfile);
            emacs_close (filefd);
            report_file_errno ("Cannot re-open temporary file",
                               build_string (tempfile), open_errno);
          }
      }
    else
      fd0 = -1; /* We are not going to read from tempfile.   */
#endif /* MSDOS */

    /* Do the unwind-protect now, even though the pid is not known, so
       that no storage allocation is done in the critical section.
       The actual PID will be filled in during the critical section.  */
    synch_process_pid = 0;
    synch_process_fd = fd0;

#ifdef MSDOS
    /* MSDOS needs different cleanup information.  */
    record_unwind_protect (call_process_cleanup,
                           Fcons (Fcurrent_buffer (),
                                  build_string (tempfile ? tempfile : "")));
#else
    record_unwind_protect (call_process_cleanup, Fcurrent_buffer ());

    block_input ();
    block_child_signal ();

#ifdef WINDOWSNT
    pid = child_setup (filefd, fd1, fd_error, new_argv, 0, current_dir);
    /* We need to record the input file of this child, for when we are
       called from call-process-region to create an async subprocess.
       That's because call-process-region's unwind procedure will
       attempt to delete the temporary input file, which will fail
       because that file is still in use.  Recording it with the child
       will allow us to delete the file when the subprocess exits.
       The second part of this is in delete_temp_file, q.v.  */
    if (pid > 0 && INTEGERP (buffer) && nargs >= 2 && !NILP (args[1]))
      record_infile (pid, xstrdup (SSDATA (infile)));
#else  /* not WINDOWSNT */

    /* vfork, and prevent local vars from being clobbered by the vfork.  */
    {
      Lisp_Object volatile buffer_volatile = buffer;
      Lisp_Object volatile coding_systems_volatile = coding_systems;
      Lisp_Object volatile current_dir_volatile = current_dir;
      bool volatile display_p_volatile = display_p;
      bool volatile output_to_buffer_volatile = output_to_buffer;
      bool volatile sa_must_free_volatile = sa_must_free;
      int volatile fd1_volatile = fd1;
      int volatile fd_error_volatile = fd_error;
      int volatile fd_output_volatile = fd_output;
      int volatile filefd_volatile = filefd;
      ptrdiff_t volatile count_volatile = count;
      ptrdiff_t volatile sa_count_volatile = sa_count;
      char **volatile new_argv_volatile = new_argv;

      pid = vfork ();
      child_errno = errno;

      buffer = buffer_volatile;
      coding_systems = coding_systems_volatile;
      current_dir = current_dir_volatile;
      display_p = display_p_volatile;
      output_to_buffer = output_to_buffer_volatile;
      sa_must_free = sa_must_free_volatile;
      fd1 = fd1_volatile;
      fd_error = fd_error_volatile;
      fd_output = fd_output_volatile;
      filefd = filefd_volatile;
      count = count_volatile;
      sa_count = sa_count_volatile;
      new_argv = new_argv_volatile;

      fd0 = synch_process_fd;
    }

    if (pid == 0)
      {
        unblock_child_signal ();

        if (fd0 >= 0)
          emacs_close (fd0);

        setsid ();

        /* Emacs ignores SIGPIPE, but the child should not.  */
        signal (SIGPIPE, SIG_DFL);

        child_setup (filefd, fd1, fd_error, new_argv, 0, current_dir);
      }

#endif /* not WINDOWSNT */

    child_errno = errno;

    if (pid > 0)
      {
        if (INTEGERP (buffer))
          record_deleted_pid (pid);
        else
          synch_process_pid = pid;
      }

    unblock_child_signal ();
    unblock_input ();

    /* The MSDOS case did this already.  */
    if (fd_error >= 0)
      emacs_close (fd_error);
#endif /* not MSDOS */

    /* Close most of our file descriptors, but not fd0
       since we will use that to read input from.  */
    emacs_close (filefd);
    if (fd_output >= 0)
      emacs_close (fd_output);
    if (fd1 >= 0 && fd1 != fd_error)
      emacs_close (fd1);
  }

  if (pid < 0)
    report_file_errno ("Doing vfork", Qnil, child_errno);

  if (INTEGERP (buffer))
    return unbind_to (count, Qnil);

  if (BUFFERP (buffer))
    Fset_buffer (buffer);

  if (NILP (buffer))
    {
      /* If BUFFER is nil, we must read process output once and then
         discard it, so setup coding system but with nil.  */
      setup_coding_system (Qnil, &process_coding);
      process_coding.dst_multibyte = 0;
    }
  else
    {
      Lisp_Object val, *args2;

      val = Qnil;
      if (!NILP (Vcoding_system_for_read))
        val = Vcoding_system_for_read;
      else
        {
          if (EQ (coding_systems, Qt))
            {
              ptrdiff_t i;

              SAFE_NALLOCA (args2, 1, nargs + 1);
              args2[0] = Qcall_process;
              for (i = 0; i < nargs; i++) args2[i + 1] = args[i];
              coding_systems
                = Ffind_operation_coding_system (nargs + 1, args2);
            }
          if (CONSP (coding_systems))
            val = XCAR (coding_systems);
          else if (CONSP (Vdefault_process_coding_system))
            val = XCAR (Vdefault_process_coding_system);
          else
            val = Qnil;
        }
      Fcheck_coding_system (val);
      /* In unibyte mode, character code conversion should not take
         place but EOL conversion should.  So, setup raw-text or one
         of the subsidiary according to the information just setup.  */
      if (NILP (BVAR (current_buffer, enable_multibyte_characters))
          && !NILP (val))
        val = raw_text_coding_system (val);
      setup_coding_system (val, &process_coding);
      process_coding.dst_multibyte
        = ! NILP (BVAR (current_buffer, enable_multibyte_characters));
    }
  process_coding.src_multibyte = 0;

  immediate_quit = 1;
  QUIT;

  if (output_to_buffer)
    {
      enum { CALLPROC_BUFFER_SIZE_MIN = 16 * 1024 };
      enum { CALLPROC_BUFFER_SIZE_MAX = 4 * CALLPROC_BUFFER_SIZE_MIN };
      char buf[CALLPROC_BUFFER_SIZE_MAX];
      int bufsize = CALLPROC_BUFFER_SIZE_MIN;
      int nread;
      bool first = 1;
      EMACS_INT total_read = 0;
      int carryover = 0;
      bool display_on_the_fly = display_p;
      struct coding_system saved_coding;

      saved_coding = process_coding;
      while (1)
        {
          /* Repeatedly read until we've filled as much as possible
             of the buffer size we have.  But don't read
             less than 1024--save that for the next bufferful.  */
          nread = carryover;
          while (nread < bufsize - 1024)
            {
              int this_read = emacs_read (fd0, buf + nread,
                                          bufsize - nread);

              if (this_read < 0)
                goto give_up;

              if (this_read == 0)
                {
                  process_coding.mode |= CODING_MODE_LAST_BLOCK;
                  break;
                }

              nread += this_read;
              total_read += this_read;

              if (display_on_the_fly)
                break;
            }

          /* Now NREAD is the total amount of data in the buffer.  */
          immediate_quit = 0;

          if (!NILP (buffer))
            {
              if (NILP (BVAR (current_buffer, enable_multibyte_characters))
                  && ! CODING_MAY_REQUIRE_DECODING (&process_coding))
                insert_1_both (buf, nread, nread, 0, 1, 0);
              else
                {                       /* We have to decode the input.  */
                  Lisp_Object curbuf;
                  ptrdiff_t count1 = SPECPDL_INDEX ();

                  XSETBUFFER (curbuf, current_buffer);
                  /* We cannot allow after-change-functions be run
                     during decoding, because that might modify the
                     buffer, while we rely on process_coding.produced to
                     faithfully reflect inserted text until we
                     TEMP_SET_PT_BOTH below.  */
                  specbind (Qinhibit_modification_hooks, Qt);
                  decode_coding_c_string (&process_coding,
                                          (unsigned char *) buf, nread, curbuf);
                  unbind_to (count1, Qnil);
                  if (display_on_the_fly
                      && CODING_REQUIRE_DETECTION (&saved_coding)
                      && ! CODING_REQUIRE_DETECTION (&process_coding))
                    {
                      /* We have detected some coding system.  But,
                         there's a possibility that the detection was
                         done by insufficient data.  So, we give up
                         displaying on the fly.  */
                      if (process_coding.produced > 0)
                        del_range_2 (process_coding.dst_pos,
                                     process_coding.dst_pos_byte,
                                     process_coding.dst_pos
                                     + process_coding.produced_char,
                                     process_coding.dst_pos_byte
                                     + process_coding.produced, 0);
                      display_on_the_fly = 0;
                      process_coding = saved_coding;
                      carryover = nread;
                      /* This is to make the above condition always
                         fails in the future.  */
                      saved_coding.common_flags
                        &= ~CODING_REQUIRE_DETECTION_MASK;
                      continue;
                    }

                  TEMP_SET_PT_BOTH (PT + process_coding.produced_char,
                                    PT_BYTE + process_coding.produced);
                  carryover = process_coding.carryover_bytes;
                  if (carryover > 0)
                    memcpy (buf, process_coding.carryover,
                            process_coding.carryover_bytes);
                }
            }

          if (process_coding.mode & CODING_MODE_LAST_BLOCK)
            break;

          /* Make the buffer bigger as we continue to read more data,
             but not past CALLPROC_BUFFER_SIZE_MAX.  */
          if (bufsize < CALLPROC_BUFFER_SIZE_MAX && total_read > 32 * bufsize)
            if ((bufsize *= 2) > CALLPROC_BUFFER_SIZE_MAX)
              bufsize = CALLPROC_BUFFER_SIZE_MAX;

          if (display_p)
            {
              if (first)
                prepare_menu_bars ();
              first = 0;
              redisplay_preserve_echo_area (1);
              /* This variable might have been set to 0 for code
                 detection.  In that case, we set it back to 1 because
                 we should have already detected a coding system.  */
              display_on_the_fly = 1;
            }
          immediate_quit = 1;
          QUIT;
        }
    give_up: ;

      Vlast_coding_system_used = CODING_ID_NAME (process_coding.id);
      /* If the caller required, let the buffer inherit the
         coding-system used to decode the process output.  */
      if (inherit_process_coding_system)
        call1 (intern ("after-insert-file-set-buffer-file-coding-system"),
               make_number (total_read));
    }

#ifndef MSDOS
  /* Wait for it to terminate, unless it already has.  */
  wait_for_termination (pid, &status, !output_to_buffer);
#endif

  immediate_quit = 0;

  /* Don't kill any children that the subprocess may have left behind
     when exiting.  */
  synch_process_pid = 0;

  SAFE_FREE ();
  unbind_to (count, Qnil);

  if (WIFSIGNALED (status))
    {
      const char *signame;

      synchronize_system_messages_locale ();
      signame = strsignal (WTERMSIG (status));

      if (signame == 0)
        signame = "unknown";

      return code_convert_string_norecord (build_string (signame),
                                           Vlocale_coding_system, 0);
    }

  eassert (WIFEXITED (status));
  return make_number (WEXITSTATUS (status));
}
\f
static void
delete_temp_file (Lisp_Object name)
{
  /* Suppress jka-compr handling, etc.  */
  ptrdiff_t count = SPECPDL_INDEX ();
  specbind (intern ("file-name-handler-alist"), Qnil);
#ifdef WINDOWSNT
  /* If this is called when the subprocess didn't exit yet, the
     attempt to delete its input file will fail.  In that case, we
     schedule the file for deletion when the subprocess exits.  This
     is the 2nd part of handling this situation; see the call to
     record_infile in call-process above, for the first part.  */
  if (!internal_delete_file (name))
    {
      Lisp_Object encoded_file = ENCODE_FILE (name);

      record_pending_deletion (SSDATA (encoded_file));
    }
#else
  internal_delete_file (name);
#endif
  unbind_to (count, Qnil);
}

/* Create a temporary file suitable for storing the input data of
   call-process-region.  NARGS and ARGS are the same as for
   call-process-region.  */

static Lisp_Object
create_temp_file (ptrdiff_t nargs, Lisp_Object *args)
{
  struct gcpro gcpro1;
  Lisp_Object filename_string;
  Lisp_Object val, start, end;
  Lisp_Object tmpdir;

  if (STRINGP (Vtemporary_file_directory))
    tmpdir = Vtemporary_file_directory;
  else
    {
      char *outf;
#ifndef DOS_NT
      outf = getenv ("TMPDIR");
      tmpdir = build_string (outf ? outf : "/tmp/");
#else /* DOS_NT */
      if ((outf = egetenv ("TMPDIR"))
          || (outf = egetenv ("TMP"))
          || (outf = egetenv ("TEMP")))
        tmpdir = build_string (outf);
      else
        tmpdir = Ffile_name_as_directory (build_string ("c:/temp"));
#endif
    }

  {
    Lisp_Object pattern = Fexpand_file_name (Vtemp_file_name_pattern, tmpdir);
    char *tempfile;

#ifdef WINDOWSNT
    /* Cannot use the result of Fexpand_file_name, because it
       downcases the XXXXXX part of the pattern, and mktemp then
       doesn't recognize it.  */
    if (!NILP (Vw32_downcase_file_names))
      {
        Lisp_Object dirname = Ffile_name_directory (pattern);

        if (NILP (dirname))
          pattern = Vtemp_file_name_pattern;
        else
          pattern = concat2 (dirname, Vtemp_file_name_pattern);
      }
#endif

    filename_string = Fcopy_sequence (ENCODE_FILE (pattern));
    GCPRO1 (filename_string);
    tempfile = SSDATA (filename_string);

    {
      int fd = mkostemp (tempfile, O_CLOEXEC);
      if (fd < 0)
        report_file_error ("Failed to open temporary file using pattern",
                           pattern);
      emacs_close (fd);
    }

    record_unwind_protect (delete_temp_file, filename_string);
  }

  start = args[0];
  end = args[1];
  /* Decide coding-system of the contents of the temporary file.  */
  if (!NILP (Vcoding_system_for_write))
    val = Vcoding_system_for_write;
  else if (NILP (BVAR (current_buffer, enable_multibyte_characters)))
    val = Qraw_text;
  else
    {
      Lisp_Object coding_systems;
      Lisp_Object *args2;
      USE_SAFE_ALLOCA;
      SAFE_NALLOCA (args2, 1, nargs + 1);
      args2[0] = Qcall_process_region;
      memcpy (args2 + 1, args, nargs * sizeof *args);
      coding_systems = Ffind_operation_coding_system (nargs + 1, args2);
      val = CONSP (coding_systems) ? XCDR (coding_systems) : Qnil;
      SAFE_FREE ();
    }
  val = complement_process_encoding_system (val);

  {
    ptrdiff_t count1 = SPECPDL_INDEX ();

    specbind (intern ("coding-system-for-write"), val);
    /* POSIX lets mk[s]temp use "."; don't invoke jka-compr if we
       happen to get a ".Z" suffix.  */
    specbind (intern ("file-name-handler-alist"), Qnil);
    Fwrite_region (start, end, filename_string, Qnil, Qlambda, Qnil, Qnil);

    unbind_to (count1, Qnil);
  }

  /* Note that Fcall_process takes care of binding
     coding-system-for-read.  */

  RETURN_UNGCPRO (filename_string);
}

DEFUN ("call-process-region", Fcall_process_region, Scall_process_region,
       3, MANY, 0,
       doc: /* Send text from START to END to a synchronous process running PROGRAM.
The remaining arguments are optional.
Delete the text if fourth arg DELETE is non-nil.

Insert output in BUFFER before point; t means current buffer; nil for
 BUFFER means discard it; 0 means discard and don't wait; and `(:file
 FILE)', where FILE is a file name string, means that it should be
 written to that file (if the file already exists it is overwritten).
BUFFER can also have the form (REAL-BUFFER STDERR-FILE); in that case,
REAL-BUFFER says what to do with standard output, as above,
while STDERR-FILE says what to do with standard error in the child.
STDERR-FILE may be nil (discard standard error output),
t (mix it with ordinary output), or a file name string.

Sixth arg DISPLAY non-nil means redisplay buffer as output is inserted.
Remaining args are passed to PROGRAM at startup as command args.

If BUFFER is 0, `call-process-region' returns immediately with value nil.
Otherwise it waits for PROGRAM to terminate
and returns a numeric exit status or a signal description string.
If you quit, the process is killed with SIGINT, or SIGKILL if you quit again.

usage: (call-process-region START END PROGRAM &optional DELETE BUFFER DISPLAY &rest ARGS)  */)
  (ptrdiff_t nargs, Lisp_Object *args)
{
  struct gcpro gcpro1;
  Lisp_Object infile;
  ptrdiff_t count = SPECPDL_INDEX ();
  Lisp_Object start = args[0];
  Lisp_Object end = args[1];
  bool empty_input;

  if (STRINGP (start))
    empty_input = SCHARS (start) == 0;
  else if (NILP (start))
    empty_input = BEG == Z;
  else
    {
      validate_region (&args[0], &args[1]);
      start = args[0];
      end = args[1];
      empty_input = XINT (start) == XINT (end);
    }

  infile = empty_input ? Qnil : create_temp_file (nargs, args);
  GCPRO1 (infile);

  if (nargs > 3 && !NILP (args[3]))
    Fdelete_region (start, end);

  if (nargs > 3)
    {
      args += 2;
      nargs -= 2;
    }
  else
    {
      args[0] = args[2];
      nargs = 2;
    }
  args[1] = infile;

  RETURN_UNGCPRO (unbind_to (count, Fcall_process (nargs, args)));
}
\f
#ifndef WINDOWSNT
static int relocate_fd (int fd, int minfd);
#endif

static char **
add_env (char **env, char **new_env, char *string)
{
  char **ep;
  bool ok = 1;
  if (string == NULL)
    return new_env;

  /* See if this string duplicates any string already in the env.
     If so, don't put it in.
     When an env var has multiple definitions,
     we keep the definition that comes first in process-environment.  */
  for (ep = env; ok && ep != new_env; ep++)
    {
      char *p = *ep, *q = string;
      while (ok)
        {
          if (*q != *p)
            break;
          if (*q == 0)
            /* The string is a lone variable name; keep it for now, we
               will remove it later.  It is a placeholder for a
               variable that is not to be included in the environment.  */
            break;
          if (*q == '=')
            ok = 0;
          p++, q++;
        }
    }
  if (ok)
    *new_env++ = string;
  return new_env;
}

/* This is the last thing run in a newly forked inferior
   either synchronous or asynchronous.
   Copy descriptors IN, OUT and ERR as descriptors 0, 1 and 2.
   Initialize inferior's priority, pgrp, connected dir and environment.
   then exec another program based on new_argv.

   If SET_PGRP, put the subprocess into a separate process group.

   CURRENT_DIR is an elisp string giving the path of the current
   directory the subprocess should have.  Since we can't really signal
   a decent error from within the child, this should be verified as an
   executable directory by the parent.  */

int
child_setup (int in, int out, int err, char **new_argv, bool set_pgrp,
             Lisp_Object current_dir)
{
  char **env;
  char *pwd_var;
#ifdef WINDOWSNT
  int cpid;
  HANDLE handles[3];
#else
  int exec_errno;

  pid_t pid = getpid ();
#endif /* WINDOWSNT */

  /* Note that use of alloca is always safe here.  It's obvious for systems
     that do not have true vfork or that have true (stack) alloca.
     If using vfork and C_ALLOCA (when Emacs used to include
     src/alloca.c) it is safe because that changes the superior's
     static variables as if the superior had done alloca and will be
     cleaned up in the usual way. */
  {
    register char *temp;
    size_t i; /* size_t, because ptrdiff_t might overflow here!  */

    i = SBYTES (current_dir);
#ifdef MSDOS
    /* MSDOS must have all environment variables malloc'ed, because
       low-level libc functions that launch subsidiary processes rely
       on that.  */
    pwd_var = xmalloc (i + 6);
#else
    pwd_var = alloca (i + 6);
#endif
    temp = pwd_var + 4;
    memcpy (pwd_var, "PWD=", 4);
    memcpy (temp, SDATA (current_dir), i);
    if (!IS_DIRECTORY_SEP (temp[i - 1])) temp[i++] = DIRECTORY_SEP;
    temp[i] = 0;

#ifndef DOS_NT
    /* We can't signal an Elisp error here; we're in a vfork.  Since
       the callers check the current directory before forking, this
       should only return an error if the directory's permissions
       are changed between the check and this chdir, but we should
       at least check.  */
    if (chdir (temp) < 0)
      _exit (EXIT_CANCELED);
#else /* DOS_NT */
    /* Get past the drive letter, so that d:/ is left alone.  */
    if (i > 2 && IS_DEVICE_SEP (temp[1]) && IS_DIRECTORY_SEP (temp[2]))
      {
        temp += 2;
        i -= 2;
      }
#endif /* DOS_NT */

    /* Strip trailing slashes for PWD, but leave "/" and "//" alone.  */
    while (i > 2 && IS_DIRECTORY_SEP (temp[i - 1]))
      temp[--i] = 0;
  }

  /* Set `env' to a vector of the strings in the environment.  */
  {
    register Lisp_Object tem;
    register char **new_env;
    char **p, **q;
    register int new_length;
    Lisp_Object display = Qnil;

    new_length = 0;

    for (tem = Vprocess_environment;
         CONSP (tem) && STRINGP (XCAR (tem));
         tem = XCDR (tem))
      {
        if (strncmp (SSDATA (XCAR (tem)), "DISPLAY", 7) == 0
            && (SDATA (XCAR (tem)) [7] == '\0'
                || SDATA (XCAR (tem)) [7] == '='))
          /* DISPLAY is specified in process-environment.  */
          display = Qt;
        new_length++;
      }

    /* If not provided yet, use the frame's DISPLAY.  */
    if (NILP (display))
      {
        Lisp_Object tmp = Fframe_parameter (selected_frame, Qdisplay);
        if (!STRINGP (tmp) && CONSP (Vinitial_environment))
          /* If still not found, Look for DISPLAY in Vinitial_environment.  */
          tmp = Fgetenv_internal (build_string ("DISPLAY"),
                                  Vinitial_environment);
        if (STRINGP (tmp))
          {
            display = tmp;
            new_length++;
          }
      }

    /* new_length + 2 to include PWD and terminating 0.  */
    env = new_env = alloca ((new_length + 2) * sizeof *env);
    /* If we have a PWD envvar, pass one down,
       but with corrected value.  */
    if (egetenv ("PWD"))
      *new_env++ = pwd_var;

    if (STRINGP (display))
      {
        char *vdata = alloca (sizeof "DISPLAY=" + SBYTES (display));
        strcpy (vdata, "DISPLAY=");
        strcat (vdata, SSDATA (display));
        new_env = add_env (env, new_env, vdata);
      }

    /* Overrides.  */
    for (tem = Vprocess_environment;
         CONSP (tem) && STRINGP (XCAR (tem));
         tem = XCDR (tem))
      new_env = add_env (env, new_env, SSDATA (XCAR (tem)));

    *new_env = 0;

    /* Remove variable names without values.  */
    p = q = env;
    while (*p != 0)
      {
        while (*q != 0 && strchr (*q, '=') == NULL)
          q++;
        *p = *q++;
        if (*p != 0)
          p++;
      }
  }


#ifdef WINDOWSNT
  prepare_standard_handles (in, out, err, handles);
  set_process_dir (SDATA (current_dir));
  /* Spawn the child.  (See w32proc.c:sys_spawnve).  */
  cpid = spawnve (_P_NOWAIT, new_argv[0], new_argv, env);
  reset_standard_handles (in, out, err, handles);
  if (cpid == -1)
    /* An error occurred while trying to spawn the process.  */
    report_file_error ("Spawning child process", Qnil);
  return cpid;

#else  /* not WINDOWSNT */
  /* Make sure that in, out, and err are not actually already in
     descriptors zero, one, or two; this could happen if Emacs is
     started with its standard in, out, or error closed, as might
     happen under X.  */
  {
    int oin = in, oout = out;

    /* We have to avoid relocating the same descriptor twice!  */

    in = relocate_fd (in, 3);

    if (out == oin)
      out = in;
    else
      out = relocate_fd (out, 3);

    if (err == oin)
      err = in;
    else if (err == oout)
      err = out;
    else
      err = relocate_fd (err, 3);
  }

#ifndef MSDOS
  /* Redirect file descriptors and clear the close-on-exec flag on the
     redirected ones.  IN, OUT, and ERR are close-on-exec so they
     need not be closed explicitly.  */
  dup2 (in, 0);
  dup2 (out, 1);
  dup2 (err, 2);

  setpgid (0, 0);
  tcsetpgrp (0, pid);

  execve (new_argv[0], new_argv, env);
  exec_errno = errno;

  /* Avoid deadlock if the child's perror writes to a full pipe; the
     pipe's reader is the parent, but with vfork the parent can't
     run until the child exits.  Truncate the diagnostic instead.  */
  fcntl (STDERR_FILENO, F_SETFL, O_NONBLOCK);

  errno = exec_errno;
  emacs_perror (new_argv[0]);
  _exit (exec_errno == ENOENT ? EXIT_ENOENT : EXIT_CANNOT_INVOKE);

#else /* MSDOS */
  pid = run_msdos_command (new_argv, pwd_var + 4, in, out, err, env);
  xfree (pwd_var);
  if (pid == -1)
    /* An error occurred while trying to run the subprocess.  */
    report_file_error ("Spawning child process", Qnil);
  return pid;
#endif  /* MSDOS */
#endif  /* not WINDOWSNT */
}

#ifndef WINDOWSNT
/* Move the file descriptor FD so that its number is not less than MINFD.
   If the file descriptor is moved at all, the original is closed on MSDOS,
   but not elsewhere as the caller will close it anyway.  */
static int
relocate_fd (int fd, int minfd)
{
  if (fd >= minfd)
    return fd;
  else
    {
      int new = fcntl (fd, F_DUPFD_CLOEXEC, minfd);
      if (new == -1)
        {
          emacs_perror ("while setting up child");
          _exit (EXIT_CANCELED);
        }
#ifdef MSDOS
      emacs_close (fd);
#endif
      return new;
    }
}
#endif /* not WINDOWSNT */

static bool
getenv_internal_1 (const char *var, ptrdiff_t varlen, char **value,
                   ptrdiff_t *valuelen, Lisp_Object env)
{
  for (; CONSP (env); env = XCDR (env))
    {
      Lisp_Object entry = XCAR (env);
      if (STRINGP (entry)
          && SBYTES (entry) >= varlen
#ifdef WINDOWSNT
          /* NT environment variables are case insensitive.  */
          && ! strnicmp (SDATA (entry), var, varlen)
#else  /* not WINDOWSNT */
          && ! memcmp (SDATA (entry), var, varlen)
#endif /* not WINDOWSNT */
          )
        {
          if (SBYTES (entry) > varlen && SREF (entry, varlen) == '=')
            {
              *value = SSDATA (entry) + (varlen + 1);
              *valuelen = SBYTES (entry) - (varlen + 1);
              return 1;
            }
          else if (SBYTES (entry) == varlen)
            {
              /* Lone variable names in Vprocess_environment mean that
                 variable should be removed from the environment. */
              *value = NULL;
              return 1;
            }
        }
    }
  return 0;
}

static bool
getenv_internal (const char *var, ptrdiff_t varlen, char **value,
                 ptrdiff_t *valuelen, Lisp_Object frame)
{
  /* Try to find VAR in Vprocess_environment first.  */
  if (getenv_internal_1 (var, varlen, value, valuelen,
                         Vprocess_environment))
    return *value ? 1 : 0;

  /* For DISPLAY try to get the values from the frame or the initial env.  */
  if (strcmp (var, "DISPLAY") == 0)
    {
      Lisp_Object display
        = Fframe_parameter (NILP (frame) ? selected_frame : frame, Qdisplay);
      if (STRINGP (display))
        {
          *value    = SSDATA (display);
          *valuelen = SBYTES (display);
          return 1;
        }
      /* If still not found, Look for DISPLAY in Vinitial_environment.  */
      if (getenv_internal_1 (var, varlen, value, valuelen,
                             Vinitial_environment))
        return *value ? 1 : 0;
    }

  return 0;
}

DEFUN ("getenv-internal", Fgetenv_internal, Sgetenv_internal, 1, 2, 0,
       doc: /* Get the value of environment variable VARIABLE.
VARIABLE should be a string.  Value is nil if VARIABLE is undefined in
the environment.  Otherwise, value is a string.

This function searches `process-environment' for VARIABLE.

If optional parameter ENV is a list, then search this list instead of
`process-environment', and return t when encountering a negative entry
\(an entry for a variable with no value).  */)
  (Lisp_Object variable, Lisp_Object env)
{
  char *value;
  ptrdiff_t valuelen;

  CHECK_STRING (variable);
  if (CONSP (env))
    {
      if (getenv_internal_1 (SSDATA (variable), SBYTES (variable),
                             &value, &valuelen, env))
        return value ? make_string (value, valuelen) : Qt;
      else
        return Qnil;
    }
  else if (getenv_internal (SSDATA (variable), SBYTES (variable),
                            &value, &valuelen, env))
    return make_string (value, valuelen);
  else
    return Qnil;
}

/* A version of getenv that consults the Lisp environment lists,
   easily callable from C.  */
char *
egetenv (const char *var)
{
  char *value;
  ptrdiff_t valuelen;

  if (getenv_internal (var, strlen (var), &value, &valuelen, Qnil))
    return value;
  else
    return 0;
}

\f
/* This is run before init_cmdargs.  */

void
init_callproc_1 (void)
{
#ifdef HAVE_NS
  const char *etc_dir = ns_etc_directory ();
  const char *path_exec = ns_exec_path ();
#endif

  Vdata_directory = decode_env_path ("EMACSDATA",
#ifdef HAVE_NS
                                             etc_dir ? etc_dir :
#endif
                                             PATH_DATA);
  Vdata_directory = Ffile_name_as_directory (Fcar (Vdata_directory));

  Vdoc_directory = decode_env_path ("EMACSDOC",
#ifdef HAVE_NS
                                             etc_dir ? etc_dir :
#endif
                                             PATH_DOC);
  Vdoc_directory = Ffile_name_as_directory (Fcar (Vdoc_directory));

  /* Check the EMACSPATH environment variable, defaulting to the
     PATH_EXEC path from epaths.h.  */
  Vexec_path = decode_env_path ("EMACSPATH",
#ifdef HAVE_NS
                                path_exec ? path_exec :
#endif
                                PATH_EXEC);
  Vexec_directory = Ffile_name_as_directory (Fcar (Vexec_path));
  /* FIXME?  For ns, path_exec should go at the front?  */
  Vexec_path = nconc2 (decode_env_path ("PATH", ""), Vexec_path);
}

/* This is run after init_cmdargs, when Vinstallation_directory is valid.  */

void
init_callproc (void)
{
  char *data_dir = egetenv ("EMACSDATA");

  register char * sh;
  Lisp_Object tempdir;
#ifdef HAVE_NS
  if (data_dir == 0)
    {
      const char *etc_dir = ns_etc_directory ();
      if (etc_dir)
        {
          data_dir = alloca (strlen (etc_dir) + 1);
          strcpy (data_dir, etc_dir);
        }
    }
#endif

  if (!NILP (Vinstallation_directory))
    {
      /* Add to the path the lib-src subdir of the installation dir.  */
      Lisp_Object tem;
      tem = Fexpand_file_name (build_string ("lib-src"),
                               Vinstallation_directory);
#ifndef MSDOS
          /* MSDOS uses wrapped binaries, so don't do this.  */
      if (NILP (Fmember (tem, Vexec_path)))
        {
#ifdef HAVE_NS
          const char *path_exec = ns_exec_path ();
#endif
          Vexec_path = decode_env_path ("EMACSPATH",
#ifdef HAVE_NS
                                        path_exec ? path_exec :
#endif
                                        PATH_EXEC);
          Vexec_path = Fcons (tem, Vexec_path);
          Vexec_path = nconc2 (decode_env_path ("PATH", ""), Vexec_path);
        }

      Vexec_directory = Ffile_name_as_directory (tem);
#endif /* not MSDOS */

      /* Maybe use ../etc as well as ../lib-src.  */
      if (data_dir == 0)
        {
          tem = Fexpand_file_name (build_string ("etc"),
                                   Vinstallation_directory);
          Vdoc_directory = Ffile_name_as_directory (tem);
        }
    }

  /* Look for the files that should be in etc.  We don't use
     Vinstallation_directory, because these files are never installed
     near the executable, and they are never in the build
     directory when that's different from the source directory.

     Instead, if these files are not in the nominal place, we try the
     source directory.  */
  if (data_dir == 0)
    {
      Lisp_Object tem, tem1, srcdir;

      srcdir = Fexpand_file_name (build_string ("../src/"),
                                  build_string (PATH_DUMPLOADSEARCH));
      tem = Fexpand_file_name (build_string ("GNU"), Vdata_directory);
      tem1 = Ffile_exists_p (tem);
      if (!NILP (Fequal (srcdir, Vinvocation_directory)) || NILP (tem1))
        {
          Lisp_Object newdir;
          newdir = Fexpand_file_name (build_string ("../etc/"),
                                      build_string (PATH_DUMPLOADSEARCH));
          tem = Fexpand_file_name (build_string ("GNU"), newdir);
          tem1 = Ffile_exists_p (tem);
          if (!NILP (tem1))
            Vdata_directory = newdir;
        }
    }

#ifndef CANNOT_DUMP
  if (initialized)
#endif
    {
      tempdir = Fdirectory_file_name (Vexec_directory);
      if (! file_accessible_directory_p (SSDATA (tempdir)))
        dir_warning ("arch-dependent data dir", Vexec_directory);
    }

  tempdir = Fdirectory_file_name (Vdata_directory);
  if (! file_accessible_directory_p (SSDATA (tempdir)))
    dir_warning ("arch-independent data dir", Vdata_directory);

  sh = getenv ("SHELL");
  Vshell_file_name = build_string (sh ? sh : "/bin/sh");

#ifdef DOS_NT
  Vshared_game_score_directory = Qnil;
#else
  Vshared_game_score_directory = build_string (PATH_GAME);
  if (NILP (Ffile_accessible_directory_p (Vshared_game_score_directory)))
    Vshared_game_score_directory = Qnil;
#endif
}

void
set_initial_environment (void)
{
  char **envp;
  for (envp = environ; *envp; envp++)
    Vprocess_environment = Fcons (build_string (*envp),
                                  Vprocess_environment);
  /* Ideally, the `copy' shouldn't be necessary, but it seems it's frequent
     to use `delete' and friends on process-environment.  */
  Vinitial_environment = Fcopy_sequence (Vprocess_environment);
}

void
syms_of_callproc (void)
{
#ifndef DOS_NT
  Vtemp_file_name_pattern = build_string ("emacsXXXXXX");
#elif defined (WINDOWSNT)
  Vtemp_file_name_pattern = build_string ("emXXXXXX");
#else
  Vtemp_file_name_pattern = build_string ("detmp.XXX");
#endif
  staticpro (&Vtemp_file_name_pattern);

  DEFVAR_LISP ("shell-file-name", Vshell_file_name,
               doc: /* File name to load inferior shells from.
Initialized from the SHELL environment variable, or to a system-dependent
default if SHELL is not set.  */);

  DEFVAR_LISP ("exec-path", Vexec_path,
               doc: /* List of directories to search programs to run in subprocesses.
Each element is a string (directory name) or nil (try default directory).  */);

  DEFVAR_LISP ("exec-suffixes", Vexec_suffixes,
               doc: /* List of suffixes to try to find executable file names.
Each element is a string.  */);
  Vexec_suffixes = Qnil;

  DEFVAR_LISP ("exec-directory", Vexec_directory,
               doc: /* Directory for executables for Emacs to invoke.
More generally, this includes any architecture-dependent files
that are built and installed from the Emacs distribution.  */);

  DEFVAR_LISP ("data-directory", Vdata_directory,
               doc: /* Directory of machine-independent files that come with GNU Emacs.
These are files intended for Emacs to use while it runs.  */);

  DEFVAR_LISP ("doc-directory", Vdoc_directory,
               doc: /* Directory containing the DOC file that comes with GNU Emacs.
This is usually the same as `data-directory'.  */);

  DEFVAR_LISP ("configure-info-directory", Vconfigure_info_directory,
               doc: /* For internal use by the build procedure only.
This is the name of the directory in which the build procedure installed
Emacs's info files; the default value for `Info-default-directory-list'
includes this.  */);
  Vconfigure_info_directory = build_string (PATH_INFO);

  DEFVAR_LISP ("shared-game-score-directory", Vshared_game_score_directory,
               doc: /* Directory of score files for games which come with GNU Emacs.
If this variable is nil, then Emacs is unable to use a shared directory.  */);
#ifdef DOS_NT
  Vshared_game_score_directory = Qnil;
#else
  Vshared_game_score_directory = build_string (PATH_GAME);
#endif

  DEFVAR_LISP ("initial-environment", Vinitial_environment,
               doc: /* List of environment variables inherited from the parent process.
Each element should be a string of the form ENVVARNAME=VALUE.
The elements must normally be decoded (using `locale-coding-system') for use.  */);
  Vinitial_environment = Qnil;

  DEFVAR_LISP ("process-environment", Vprocess_environment,
               doc: /* List of overridden environment variables for subprocesses to inherit.
Each element should be a string of the form ENVVARNAME=VALUE.

Entries in this list take precedence to those in the frame-local
environments.  Therefore, let-binding `process-environment' is an easy
way to temporarily change the value of an environment variable,
irrespective of where it comes from.  To use `process-environment' to
remove an environment variable, include only its name in the list,
without "=VALUE".

This variable is set to nil when Emacs starts.

If multiple entries define the same variable, the first one always
takes precedence.

Non-ASCII characters are encoded according to the initial value of
`locale-coding-system', i.e. the elements must normally be decoded for
use.

See `setenv' and `getenv'.  */);
  Vprocess_environment = Qnil;

  defsubr (&Scall_process);
  defsubr (&Sgetenv_internal);
  defsubr (&Scall_process_region);
}