root/src/callproc.c

DEFINITIONS

1. get_current_directory
2. record_kill_process
3. delete_temp_file
4. call_process_kill
5. call_process_cleanup
6. call_process
7. create_temp_file
8. add_env
9. exec_failed
10. child_setup
11. emacs_posix_spawn_init_actions
12. emacs_posix_spawn_init_attributes
13. emacs_spawn
14. getenv_internal_1
15. getenv_internal
16. egetenv_internal
17. make_environment_block
18. init_callproc_1
19. init_callproc
20. set_initial_environment
21. syms_of_callproc

     1 /* Synchronous subprocess invocation for GNU Emacs.
     2 
     3 Copyright (C) 1985-1988, 1993-1995, 1999-2023 Free Software Foundation,
     4 Inc.
     5 
     6 This file is part of GNU Emacs.
     7 
     8 GNU Emacs is free software: you can redistribute it and/or modify
     9 it under the terms of the GNU General Public License as published by
    10 the Free Software Foundation, either version 3 of the License, or (at
    11 your option) any later version.
    12 
    13 GNU Emacs 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
    16 GNU General Public License for more details.
    17 
    18 You should have received a copy of the GNU General Public License
    19 along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
    20 
    21 
    22 #include <config.h>
    23 #include <errno.h>
    24 #include <stdlib.h>
    25 #include <sys/types.h>
    26 #include <unistd.h>
    27 
    28 #ifdef MSDOS
    29 extern char **environ;
    30 #endif
    31 
    32 #include <sys/file.h>
    33 #include <fcntl.h>
    34 
    35 /* In order to be able to use `posix_spawn', it needs to support some
    36    variant of `chdir' as well as `setsid'.  */
    37 #if defined HAVE_SPAWN_H && defined HAVE_POSIX_SPAWN        \
    38   && defined HAVE_POSIX_SPAWNATTR_SETFLAGS                  \
    39   && (defined HAVE_POSIX_SPAWN_FILE_ACTIONS_ADDCHDIR        \
    40       || defined HAVE_POSIX_SPAWN_FILE_ACTIONS_ADDCHDIR_NP) \
    41   && defined HAVE_DECL_POSIX_SPAWN_SETSID                   \
    42   && HAVE_DECL_POSIX_SPAWN_SETSID == 1                      \
    43   /* posix_spawnattr_setflags rejects POSIX_SPAWN_SETSID on \
    44      Haiku */                                               \
    45   && !defined HAIKU
    46 # include <spawn.h>
    47 # define USABLE_POSIX_SPAWN 1
    48 #else
    49 # define USABLE_POSIX_SPAWN 0
    50 #endif
    51 
    52 #include "lisp.h"
    53 
    54 #ifdef SETUP_SLAVE_PTY
    55 # include <sys/stream.h>
    56 # include <sys/stropts.h>
    57 #endif
    58 
    59 #ifdef WINDOWSNT
    60 #include <sys/socket.h> /* for fcntl */
    61 #include <windows.h>
    62 #include "w32.h"
    63 #define _P_NOWAIT 1     /* from process.h */
    64 #endif
    65 
    66 #ifdef MSDOS    /* Demacs 1.1.1 91/10/16 HIRANO Satoshi */
    67 #include <sys/stat.h>
    68 #include <sys/param.h>
    69 #endif /* MSDOS */
    70 
    71 #include "commands.h"
    72 #include "buffer.h"
    73 #include "coding.h"
    74 #include <epaths.h>
    75 #include "process.h"
    76 #include "syssignal.h"
    77 #include "syswait.h"
    78 #include "blockinput.h"
    79 #include "frame.h"
    80 #include "systty.h"
    81 #include "keyboard.h"
    82 
    83 #ifdef MSDOS
    84 #include "msdos.h"
    85 #endif
    86 
    87 #ifdef HAVE_NS
    88 #include "nsterm.h"
    89 #endif
    90 
    91 #ifdef HAVE_PGTK
    92 #include "pgtkterm.h"
    93 #endif
    94 
    95 /* Pattern used by call-process-region to make temp files.  */
    96 static Lisp_Object Vtemp_file_name_pattern;
    97 
    98 /* The next two variables are used while record-unwind-protect is in place
    99    during call-process for a subprocess for which record_deleted_pid has
   100    not yet been called.  At other times, synch_process_pid is zero and
   101    synch_process_tempfile's contents are irrelevant.  Doing this via static
   102    C variables is more convenient than putting them into the arguments
   103    of record-unwind-protect, as they need to be updated at randomish
   104    times in the code, and Lisp cannot always store these values as
   105    Emacs integers.  It's safe to use static variables here, as the
   106    code is never invoked reentrantly.  */
   107 
   108 /* If nonzero, a process-ID that has not been reaped.  */
   109 static pid_t synch_process_pid;
   110 
   111 /* If a string, the name of a temp file that has not been removed.  */
   112 #ifdef MSDOS
   113 static Lisp_Object synch_process_tempfile;
   114 #else
   115 # define synch_process_tempfile make_fixnum (0)
   116 #endif
   117 
   118 /* Indexes of file descriptors that need closing on call_process_kill.  */
   119 enum
   120   {
   121     /* The subsidiary process's stdout and stderr.  stdin is handled
   122        separately, in either Fcall_process_region or create_temp_file.  */
   123     CALLPROC_STDOUT, CALLPROC_STDERR,
   124 
   125     /* How to read from a pipe (or substitute) from the subsidiary process.  */
   126     CALLPROC_PIPEREAD,
   127 
   128     /* A bound on the number of file descriptors.  */
   129     CALLPROC_FDS
   130   };
   131 
   132 static Lisp_Object call_process (ptrdiff_t, Lisp_Object *, int, specpdl_ref);
   133 
   134 #ifdef DOS_NT
   135 # define CHILD_SETUP_TYPE int
   136 #else
   137 # define CHILD_SETUP_TYPE _Noreturn void
   138 #endif
   139 
   140 static CHILD_SETUP_TYPE child_setup (int, int, int, char **, char **,
   141                                      const char *);
   142 
   143 /* Return the current buffer's working directory, or the home
   144    directory if it's unreachable.  If ENCODE is true, return as a string
   145    suitable for a system call; otherwise, return a string in its
   146    internal representation.  Signal an error if the result would not be
   147    an accessible directory.  */
   148 
   149 Lisp_Object
   150 get_current_directory (bool encode)
   151 {
   152   Lisp_Object curdir = BVAR (current_buffer, directory);
   153   Lisp_Object dir = Funhandled_file_name_directory (curdir);
   154 
   155   /* If the file name handler says that dir is unreachable, use
   156      a sensible default. */
   157   if (NILP (dir))
   158     dir = build_string ("~");
   159 
   160   dir = expand_and_dir_to_file (dir);
   161   Lisp_Object encoded_dir = ENCODE_FILE (remove_slash_colon (dir));
   162 
   163   if (! file_accessible_directory_p (encoded_dir))
   164     report_file_error ("Setting current directory", curdir);
   165 
   166   return encode ? encoded_dir : dir;
   167 }
   168 
   169 /* If P is reapable, record it as a deleted process and kill it.
   170    Do this in a critical section.  Unless PID is wedged it will be
   171    reaped on receipt of the first SIGCHLD after the critical section.  */
   172 
   173 void
   174 record_kill_process (struct Lisp_Process *p, Lisp_Object tempfile)
   175 {
   176 #ifndef MSDOS
   177   sigset_t oldset;
   178   block_child_signal (&oldset);
   179 
   180   if (p->alive)
   181     {
   182       record_deleted_pid (p->pid, tempfile);
   183       p->alive = 0;
   184       kill (- p->pid, SIGKILL);
   185     }
   186 
   187   unblock_child_signal (&oldset);
   188 #endif  /* !MSDOS */
   189 }
   190 
   191 /* Clean up files, file descriptors and processes created by Fcall_process.  */
   192 
   193 static void
   194 delete_temp_file (Lisp_Object name)
   195 {
   196   unlink (SSDATA (name));
   197 }
   198 
   199 static void
   200 call_process_kill (void *ptr)
   201 {
   202   int *callproc_fd = ptr;
   203   int i;
   204   for (i = 0; i < CALLPROC_FDS; i++)
   205     if (0 <= callproc_fd[i])
   206       emacs_close (callproc_fd[i]);
   207 
   208   if (synch_process_pid)
   209     {
   210       struct Lisp_Process proc;
   211       proc.alive = 1;
   212       proc.pid = synch_process_pid;
   213       record_kill_process (&proc, synch_process_tempfile);
   214       synch_process_pid = 0;
   215     }
   216   else if (STRINGP (synch_process_tempfile))
   217     delete_temp_file (synch_process_tempfile);
   218 }
   219 
   220 /* Clean up when exiting Fcall_process: restore the buffer, and
   221    kill the subsidiary process group if the process still exists.  */
   222 
   223 static void
   224 call_process_cleanup (Lisp_Object buffer)
   225 {
   226   Fset_buffer (buffer);
   227 
   228 #ifndef MSDOS
   229   if (synch_process_pid)
   230     {
   231       kill (-synch_process_pid, SIGINT);
   232       message1 ("Waiting for process to die...(type C-g again to kill it instantly)");
   233 
   234       /* This will quit on C-g.  */
   235       bool wait_ok = wait_for_termination (synch_process_pid, NULL, true);
   236       synch_process_pid = 0;
   237       message1 (wait_ok
   238                 ? "Waiting for process to die...done"
   239                 : "Waiting for process to die...internal error");
   240     }
   241 #endif  /* !MSDOS */
   242 }
   243 
   244 #ifdef DOS_NT
   245 static mode_t const default_output_mode = S_IREAD | S_IWRITE;
   246 #else
   247 static mode_t const default_output_mode = 0666;
   248 #endif
   249 
   250 DEFUN ("call-process", Fcall_process, Scall_process, 1, MANY, 0,
   251        doc: /* Call PROGRAM synchronously in separate process.
   252 The remaining arguments are optional.
   253 
   254 The program's input comes from file INFILE (nil means `null-device').
   255 If INFILE is a relative path, it will be looked for relative to the
   256 directory where the process is run (see below).  If you want to make the
   257 input come from an Emacs buffer, use `call-process-region' instead.
   258 
   259 Third argument DESTINATION specifies how to handle program's output.
   260 (\"Output\" here means both standard output and standard error
   261 output.)
   262 If DESTINATION is a buffer or the name of a buffer, or t (which stands for
   263 the current buffer), it means insert output in that buffer before point.
   264 If DESTINATION is nil, it means discard output; 0 means discard
   265  and don't wait for the program to terminate.
   266 If DESTINATION is `(:file FILE)', where FILE is a file name string,
   267  it means that output should be written to that file (if the file
   268  already exists it is overwritten).
   269 DESTINATION can also have the form (REAL-BUFFER STDERR-FILE); in that case,
   270  REAL-BUFFER says what to do with standard output, as above,
   271  while STDERR-FILE says what to do with standard error in the child.
   272  STDERR-FILE may be nil (discard standard error output),
   273  t (mix it with ordinary output), or a file name string.
   274 
   275 Fourth arg DISPLAY non-nil means redisplay buffer as output is inserted.
   276 Remaining arguments ARGS are strings passed as command arguments to PROGRAM.
   277 
   278 If PROGRAM is not an absolute file name, `call-process' will look for
   279 PROGRAM in `exec-path' (which is a list of directories).
   280 
   281 If executable PROGRAM can't be found as an executable, `call-process'
   282 signals a Lisp error.  `call-process' reports errors in execution of
   283 the program only through its return and output.
   284 
   285 If DESTINATION is 0, `call-process' returns immediately with value nil.
   286 Otherwise it waits for PROGRAM to terminate
   287 and returns a numeric exit status or a signal description string.
   288 If you quit, the process is killed with SIGINT, or SIGKILL if you quit again.
   289 
   290 The process runs in `default-directory' if that is local (as
   291 determined by `unhandled-file-name-directory'), or "~" otherwise.  If
   292 you want to run a process in a remote directory use `process-file'.
   293 
   294 usage: (call-process PROGRAM &optional INFILE DESTINATION DISPLAY &rest ARGS)  */)
   295   (ptrdiff_t nargs, Lisp_Object *args)
   296 {
   297   Lisp_Object infile, encoded_infile;
   298   int filefd;
   299   specpdl_ref count = SPECPDL_INDEX ();
   300 
   301   if (nargs >= 2 && ! NILP (args[1]))
   302     {
   303       /* Expand infile relative to the current buffer's current
   304          directory, or its unhandled equivalent ("~").  */
   305       infile = Fexpand_file_name (args[1], get_current_directory (false));
   306       CHECK_STRING (infile);
   307     }
   308   else
   309     infile = build_string (NULL_DEVICE);
   310 
   311   /* Remove "/:" from INFILE.  */
   312   infile = remove_slash_colon (infile);
   313 
   314   encoded_infile = ENCODE_FILE (infile);
   315 
   316   filefd = emacs_open (SSDATA (encoded_infile), O_RDONLY, 0);
   317   if (filefd < 0)
   318     report_file_error ("Opening process input file", infile);
   319   record_unwind_protect_int (close_file_unwind, filefd);
   320   return unbind_to (count, call_process (nargs, args, filefd,
   321                                          make_invalid_specpdl_ref ()));
   322 }
   323 
   324 /* Like Fcall_process (NARGS, ARGS), except use FILEFD as the input file.
   325 
   326    If TEMPFILE_INDEX is valid, it is the specpdl index of an
   327    unwinder that is intended to remove the input temporary file; in
   328    this case NARGS must be at least 2 and ARGS[1] is the file's name.
   329 
   330    At entry, the specpdl stack top entry must be close_file_unwind (FILEFD).  */
   331 
   332 static Lisp_Object
   333 call_process (ptrdiff_t nargs, Lisp_Object *args, int filefd,
   334               specpdl_ref tempfile_index)
   335 {
   336   Lisp_Object buffer, current_dir, path;
   337   bool display_p;
   338   int fd0;
   339   int callproc_fd[CALLPROC_FDS];
   340   int status;
   341   ptrdiff_t i;
   342   specpdl_ref count = SPECPDL_INDEX ();
   343   USE_SAFE_ALLOCA;
   344 
   345   char **new_argv;
   346   /* File to use for stderr in the child.
   347      t means use same as standard output.  */
   348   Lisp_Object error_file;
   349   Lisp_Object output_file = Qnil;
   350 #ifdef MSDOS    /* Demacs 1.1.1 91/10/16 HIRANO Satoshi */
   351   char *tempfile = NULL;
   352 #else
   353   sigset_t oldset;
   354   pid_t pid = -1;
   355 #endif
   356   int child_errno;
   357   int fd_output, fd_error;
   358   struct coding_system process_coding; /* coding-system of process output */
   359   struct coding_system argument_coding; /* coding-system of arguments */
   360   /* Set to the return value of Ffind_operation_coding_system.  */
   361   Lisp_Object coding_systems;
   362   bool discard_output;
   363 
   364   if (synch_process_pid)
   365     error ("call-process invoked recursively");
   366 
   367   /* Qt denotes that Ffind_operation_coding_system is not yet called.  */
   368   coding_systems = Qt;
   369 
   370   CHECK_STRING (args[0]);
   371 
   372   error_file = Qt;
   373 
   374 #ifndef subprocesses
   375   /* Without asynchronous processes we cannot have BUFFER == 0.  */
   376   if (nargs >= 3
   377       && (FIXNUMP (CONSP (args[2]) ? XCAR (args[2]) : args[2])))
   378     error ("Operating system cannot handle asynchronous subprocesses");
   379 #endif /* subprocesses */
   380 
   381   /* Decide the coding-system for giving arguments.  */
   382   {
   383     Lisp_Object val, *args2;
   384 
   385     /* If arguments are supplied, we may have to encode them.  */
   386     if (nargs >= 5)
   387       {
   388         bool must_encode = 0;
   389         Lisp_Object coding_attrs;
   390 
   391         for (i = 4; i < nargs; i++)
   392           CHECK_STRING (args[i]);
   393 
   394         for (i = 4; i < nargs; i++)
   395           if (STRING_MULTIBYTE (args[i]))
   396             must_encode = 1;
   397 
   398         if (!NILP (Vcoding_system_for_write))
   399           val = Vcoding_system_for_write;
   400         else if (! must_encode)
   401           val = Qraw_text;
   402         else
   403           {
   404             SAFE_NALLOCA (args2, 1, nargs + 1);
   405             args2[0] = Qcall_process;
   406             for (i = 0; i < nargs; i++) args2[i + 1] = args[i];
   407             coding_systems = Ffind_operation_coding_system (nargs + 1, args2);
   408             val = CONSP (coding_systems) ? XCDR (coding_systems) : Qnil;
   409           }
   410         val = complement_process_encoding_system (val);
   411         setup_coding_system (Fcheck_coding_system (val), &argument_coding);
   412         coding_attrs = CODING_ID_ATTRS (argument_coding.id);
   413         if (NILP (CODING_ATTR_ASCII_COMPAT (coding_attrs)))
   414           {
   415             /* We should not use an ASCII incompatible coding system.  */
   416             val = raw_text_coding_system (val);
   417             setup_coding_system (val, &argument_coding);
   418           }
   419       }
   420   }
   421 
   422   if (nargs < 3)
   423     buffer = Qnil;
   424   else
   425     {
   426       buffer = args[2];
   427 
   428       /* If BUFFER is a list, its meaning is (BUFFER-FOR-STDOUT
   429          FILE-FOR-STDERR), unless the first element is :file, in which case see
   430          the next paragraph. */
   431       if (CONSP (buffer) && !EQ (XCAR (buffer), QCfile))
   432         {
   433           if (CONSP (XCDR (buffer)))
   434             {
   435               Lisp_Object stderr_file;
   436               stderr_file = XCAR (XCDR (buffer));
   437 
   438               if (NILP (stderr_file) || EQ (Qt, stderr_file))
   439                 error_file = stderr_file;
   440               else
   441                 error_file = Fexpand_file_name (stderr_file, Qnil);
   442             }
   443 
   444           buffer = XCAR (buffer);
   445         }
   446 
   447       /* If the buffer is (still) a list, it might be a (:file "file") spec. */
   448       if (CONSP (buffer) && EQ (XCAR (buffer), QCfile))
   449         {
   450           Lisp_Object ofile = XCDR (buffer);
   451           if (CONSP (ofile))
   452             ofile = XCAR (ofile);
   453           CHECK_STRING (ofile);
   454           output_file = Fexpand_file_name (ofile,
   455                                            BVAR (current_buffer, directory));
   456           CHECK_STRING (output_file);
   457           buffer = Qnil;
   458         }
   459 
   460       if (! (NILP (buffer) || EQ (buffer, Qt) || FIXNUMP (buffer)))
   461         {
   462           Lisp_Object spec_buffer = buffer;
   463           buffer = Fget_buffer_create (buffer, Qnil);
   464           /* Mention the buffer name for a better error message.  */
   465           if (NILP (buffer))
   466             CHECK_BUFFER (spec_buffer);
   467           CHECK_BUFFER (buffer);
   468         }
   469     }
   470 
   471   /* Make sure that the child will be able to chdir to the current
   472      buffer's current directory, or its unhandled equivalent.  We
   473      can't just have the child check for an error when it does the
   474      chdir, since it's in a vfork.  */
   475   current_dir = get_current_directory (true);
   476 
   477   if (STRINGP (error_file))
   478     {
   479       error_file = remove_slash_colon (error_file);
   480       error_file = ENCODE_FILE (error_file);
   481     }
   482   if (STRINGP (output_file))
   483     {
   484       output_file = remove_slash_colon (output_file);
   485       output_file = ENCODE_FILE (output_file);
   486     }
   487 
   488   display_p = INTERACTIVE && nargs >= 4 && !NILP (args[3]);
   489 
   490   for (i = 0; i < CALLPROC_FDS; i++)
   491     callproc_fd[i] = -1;
   492 #ifdef MSDOS
   493   synch_process_tempfile = make_fixnum (0);
   494 #endif
   495   record_unwind_protect_ptr (call_process_kill, callproc_fd);
   496 
   497   /* Search for program; barf if not found.  */
   498   {
   499     int ok;
   500 
   501     ok = openp (Vexec_path, args[0], Vexec_suffixes, &path,
   502                 make_fixnum (X_OK), false, false);
   503     if (ok < 0)
   504       report_file_error ("Searching for program", args[0]);
   505   }
   506 
   507   /* Remove "/:" from PATH.  */
   508   path = remove_slash_colon (path);
   509 
   510   SAFE_NALLOCA (new_argv, 1, nargs < 4 ? 2 : nargs - 2);
   511 
   512   if (nargs > 4)
   513     {
   514       ptrdiff_t i;
   515 
   516       argument_coding.dst_multibyte = 0;
   517       for (i = 4; i < nargs; i++)
   518         {
   519           argument_coding.src_multibyte = STRING_MULTIBYTE (args[i]);
   520           if (CODING_REQUIRE_ENCODING (&argument_coding))
   521             /* We must encode this argument.  */
   522             args[i] = encode_coding_string (&argument_coding, args[i], 1);
   523         }
   524       for (i = 4; i < nargs; i++)
   525         new_argv[i - 3] = SSDATA (args[i]);
   526       new_argv[i - 3] = 0;
   527     }
   528   else
   529     new_argv[1] = 0;
   530   path = ENCODE_FILE (path);
   531   new_argv[0] = SSDATA (path);
   532 
   533   discard_output = FIXNUMP (buffer) || (NILP (buffer) && NILP (output_file));
   534 
   535 #ifdef MSDOS
   536   if (! discard_output && ! STRINGP (output_file))
   537     {
   538       char const *tmpdir = egetenv ("TMPDIR");
   539       char const *outf = tmpdir ? tmpdir : "";
   540       tempfile = alloca (strlen (outf) + 20);
   541       strcpy (tempfile, outf);
   542       dostounix_filename (tempfile);
   543       if (*tempfile == '\0' || tempfile[strlen (tempfile) - 1] != '/')
   544         strcat (tempfile, "/");
   545       strcat (tempfile, "emXXXXXX");
   546       mktemp (tempfile);
   547       if (!*tempfile)
   548         report_file_error ("Opening process output file", Qnil);
   549       output_file = build_string (tempfile);
   550       synch_process_tempfile = output_file;
   551     }
   552 #endif
   553 
   554   if (discard_output)
   555     {
   556       fd_output = emacs_open (NULL_DEVICE, O_WRONLY, 0);
   557       if (fd_output < 0)
   558         report_file_error ("Opening null device", Qnil);
   559     }
   560   else if (STRINGP (output_file))
   561     {
   562       fd_output = emacs_open (SSDATA (output_file),
   563                               O_WRONLY | O_CREAT | O_TRUNC | O_TEXT,
   564                               default_output_mode);
   565       if (fd_output < 0)
   566         {
   567           int open_errno = errno;
   568           output_file = DECODE_FILE (output_file);
   569           report_file_errno ("Opening process output file",
   570                              output_file, open_errno);
   571         }
   572     }
   573   else
   574     {
   575       int fd[2];
   576       if (emacs_pipe (fd) != 0)
   577         report_file_error ("Creating process pipe", Qnil);
   578       callproc_fd[CALLPROC_PIPEREAD] = fd[0];
   579       fd_output = fd[1];
   580     }
   581   callproc_fd[CALLPROC_STDOUT] = fd_output;
   582 
   583   fd_error = fd_output;
   584 
   585   if (STRINGP (error_file) || (NILP (error_file) && !discard_output))
   586     {
   587       fd_error = emacs_open ((STRINGP (error_file)
   588                               ? SSDATA (error_file)
   589                               : NULL_DEVICE),
   590                              O_WRONLY | O_CREAT | O_TRUNC | O_TEXT,
   591                              default_output_mode);
   592       if (fd_error < 0)
   593         {
   594           int open_errno = errno;
   595           report_file_errno ("Cannot redirect stderr",
   596                              (STRINGP (error_file)
   597                               ? DECODE_FILE (error_file)
   598                               : build_string (NULL_DEVICE)),
   599                              open_errno);
   600         }
   601       callproc_fd[CALLPROC_STDERR] = fd_error;
   602     }
   603 
   604   char **env = make_environment_block (current_dir);
   605 
   606 #ifdef MSDOS /* MW, July 1993 */
   607   status = child_setup (filefd, fd_output, fd_error, new_argv, env,
   608                         SSDATA (current_dir));
   609 
   610   if (status < 0)
   611     {
   612       child_errno = errno;
   613       unbind_to (count, Qnil);
   614       synchronize_system_messages_locale ();
   615       return
   616         code_convert_string_norecord (build_string (strerror (child_errno)),
   617                                       Vlocale_coding_system, 0);
   618     }
   619 
   620   for (i = 0; i < CALLPROC_FDS; i++)
   621     if (0 <= callproc_fd[i])
   622       {
   623         emacs_close (callproc_fd[i]);
   624         callproc_fd[i] = -1;
   625       }
   626   emacs_close (filefd);
   627   clear_unwind_protect (specpdl_ref_add (count, -1));
   628 
   629   if (tempfile)
   630     {
   631       /* Since CRLF is converted to LF within `decode_coding', we
   632          can always open a file with binary mode.  */
   633       callproc_fd[CALLPROC_PIPEREAD] = emacs_open (tempfile, O_RDONLY, 0);
   634       if (callproc_fd[CALLPROC_PIPEREAD] < 0)
   635         {
   636           int open_errno = errno;
   637           report_file_errno ("Cannot re-open temporary file",
   638                              build_string (tempfile), open_errno);
   639         }
   640     }
   641 
   642 #endif /* MSDOS */
   643 
   644   /* Do the unwind-protect now, even though the pid is not known, so
   645      that no storage allocation is done in the critical section.
   646      The actual PID will be filled in during the critical section.  */
   647   record_unwind_protect (call_process_cleanup, Fcurrent_buffer ());
   648 
   649 #ifndef MSDOS
   650 
   651   child_signal_init ();
   652   block_input ();
   653   block_child_signal (&oldset);
   654 
   655   child_errno
   656     = emacs_spawn (&pid, filefd, fd_output, fd_error, new_argv, env,
   657                    SSDATA (current_dir), NULL, false, false, &oldset);
   658   eassert ((child_errno == 0) == (0 < pid));
   659 
   660   if (pid > 0)
   661     {
   662       synch_process_pid = pid;
   663 
   664       if (FIXNUMP (buffer))
   665         {
   666           if (!specpdl_ref_valid_p (tempfile_index))
   667             record_deleted_pid (pid, Qnil);
   668           else
   669             {
   670               eassert (1 < nargs);
   671               record_deleted_pid (pid, args[1]);
   672               clear_unwind_protect (tempfile_index);
   673             }
   674           synch_process_pid = 0;
   675         }
   676     }
   677 
   678   unblock_child_signal (&oldset);
   679   unblock_input ();
   680 
   681   if (pid < 0)
   682     report_file_errno (CHILD_SETUP_ERROR_DESC, Qnil, child_errno);
   683 
   684   /* Close our file descriptors, except for callproc_fd[CALLPROC_PIPEREAD]
   685      since we will use that to read input from.  */
   686   for (i = 0; i < CALLPROC_FDS; i++)
   687     if (i != CALLPROC_PIPEREAD && 0 <= callproc_fd[i])
   688       {
   689         emacs_close (callproc_fd[i]);
   690         callproc_fd[i] = -1;
   691       }
   692   emacs_close (filefd);
   693   clear_unwind_protect (specpdl_ref_add (count, -1));
   694 
   695 #endif /* not MSDOS */
   696 
   697   if (FIXNUMP (buffer))
   698     return unbind_to (count, Qnil);
   699 
   700   if (BUFFERP (buffer))
   701     Fset_buffer (buffer);
   702 
   703   fd0 = callproc_fd[CALLPROC_PIPEREAD];
   704 
   705   if (0 <= fd0)
   706     {
   707       Lisp_Object val, *args2;
   708 
   709       val = Qnil;
   710       if (!NILP (Vcoding_system_for_read))
   711         val = Vcoding_system_for_read;
   712       else
   713         {
   714           if (EQ (coding_systems, Qt))
   715             {
   716               ptrdiff_t i;
   717 
   718               SAFE_NALLOCA (args2, 1, nargs + 1);
   719               args2[0] = Qcall_process;
   720               for (i = 0; i < nargs; i++) args2[i + 1] = args[i];
   721               coding_systems
   722                 = Ffind_operation_coding_system (nargs + 1, args2);
   723             }
   724           if (CONSP (coding_systems))
   725             val = XCAR (coding_systems);
   726           else if (CONSP (Vdefault_process_coding_system))
   727             val = XCAR (Vdefault_process_coding_system);
   728           else
   729             val = Qnil;
   730         }
   731       Fcheck_coding_system (val);
   732       /* In unibyte mode, character code conversion should not take
   733          place but EOL conversion should.  So, setup raw-text or one
   734          of the subsidiary according to the information just setup.  */
   735       if (NILP (BVAR (current_buffer, enable_multibyte_characters))
   736           && !NILP (val))
   737         val = raw_text_coding_system (val);
   738       setup_coding_system (val, &process_coding);
   739       process_coding.dst_multibyte
   740         = ! NILP (BVAR (current_buffer, enable_multibyte_characters));
   741       process_coding.src_multibyte = 0;
   742     }
   743 
   744   if (0 <= fd0)
   745     {
   746       enum { CALLPROC_BUFFER_SIZE_MIN = 16 * 1024 };
   747       enum { CALLPROC_BUFFER_SIZE_MAX = 4 * CALLPROC_BUFFER_SIZE_MIN };
   748       char buf[CALLPROC_BUFFER_SIZE_MAX];
   749       int bufsize = CALLPROC_BUFFER_SIZE_MIN;
   750       int nread;
   751       EMACS_INT total_read = 0;
   752       int carryover = 0;
   753       bool display_on_the_fly = display_p;
   754       struct coding_system saved_coding = process_coding;
   755       ptrdiff_t prepared_pos = 0; /* prepare_to_modify_buffer was last
   756                                      called here.  */
   757 
   758       while (1)
   759         {
   760           /* Repeatedly read until we've filled as much as possible
   761              of the buffer size we have.  But don't read
   762              less than 1024--save that for the next bufferful.  */
   763           nread = carryover;
   764           while (nread < bufsize - 1024)
   765             {
   766               int this_read = emacs_read_quit (fd0, buf + nread,
   767                                                bufsize - nread);
   768 
   769               if (this_read < 0)
   770                 goto give_up;
   771 
   772               if (this_read == 0)
   773                 {
   774                   process_coding.mode |= CODING_MODE_LAST_BLOCK;
   775                   break;
   776                 }
   777 
   778               nread += this_read;
   779               total_read += this_read;
   780 
   781               if (display_on_the_fly)
   782                 break;
   783             }
   784           /* CHANGE FUNCTIONS
   785              For each iteration of the enclosing while (1) loop which
   786              yields data (i.e. nread > 0), before- and
   787              after-change-functions are each invoked exactly once.
   788              This is done directly from the current function only, by
   789              calling prepare_to_modify_buffer and signal_after_change.
   790              It is not done here by directing another function such as
   791              insert_1_both to call them.  The call to
   792              prepare_to_modify_buffer follows this comment, and there
   793              is one call to signal_after_change in each of the
   794              branches of the next `else if'.
   795 
   796              Exceptionally, the insertion into the buffer is aborted
   797              at the call to del_range_2 ~45 lines further down, this
   798              function removing the newly inserted data.  At this stage
   799              prepare_to_modify_buffer has been called, but
   800              signal_after_change hasn't.  A continue statement
   801              restarts the enclosing while (1) loop.  A second,
   802              unwanted, call to `prepare_to_modify_buffer' is inhibited
   803              by the test prepared_pos < PT.  The data are inserted
   804              again, and this time signal_after_change gets called,
   805              balancing the previous call to prepare_to_modify_buffer.  */
   806           if ((prepared_pos < PT) && nread)
   807             {
   808               prepare_to_modify_buffer (PT, PT, NULL);
   809               prepared_pos = PT;
   810             }
   811 
   812           /* Now NREAD is the total amount of data in the buffer.  */
   813 
   814           if (!nread)
   815             ;
   816           else if (NILP (BVAR (current_buffer, enable_multibyte_characters))
   817                    && ! CODING_MAY_REQUIRE_DECODING (&process_coding))
   818             {
   819               insert_1_both (buf, nread, nread, 0, 0, 0);
   820               signal_after_change (PT - nread, 0, nread);
   821             }
   822           else
   823             {                   /* We have to decode the input.  */
   824               Lisp_Object curbuf;
   825               specpdl_ref count1 = SPECPDL_INDEX ();
   826 
   827               XSETBUFFER (curbuf, current_buffer);
   828               /* We cannot allow after-change-functions be run
   829                  during decoding, because that might modify the
   830                  buffer, while we rely on process_coding.produced to
   831                  faithfully reflect inserted text until we
   832                  TEMP_SET_PT_BOTH below.  */
   833               specbind (Qinhibit_modification_hooks, Qt);
   834               decode_coding_c_string (&process_coding,
   835                                       (unsigned char *) buf, nread, curbuf);
   836               unbind_to (count1, Qnil);
   837               if (display_on_the_fly
   838                   && CODING_REQUIRE_DETECTION (&saved_coding)
   839                   && ! CODING_REQUIRE_DETECTION (&process_coding))
   840                 {
   841                   /* We have detected some coding system, but the
   842                      detection may have been via insufficient data.
   843                      So give up displaying on the fly.  */
   844                   if (process_coding.produced > 0)
   845                     del_range_2 (process_coding.dst_pos,
   846                                  process_coding.dst_pos_byte,
   847                                  (process_coding.dst_pos
   848                                   + process_coding.produced_char),
   849                                  (process_coding.dst_pos_byte
   850                                   + process_coding.produced),
   851                                  0);
   852                   display_on_the_fly = false;
   853                   process_coding = saved_coding;
   854                   carryover = nread;
   855                   /* Make the above condition always fail in the future.  */
   856                   saved_coding.common_flags
   857                     &= ~CODING_REQUIRE_DETECTION_MASK;
   858                   continue;
   859                 }
   860 
   861               TEMP_SET_PT_BOTH (PT + process_coding.produced_char,
   862                                 PT_BYTE + process_coding.produced);
   863               signal_after_change (PT - process_coding.produced_char,
   864                                    0, process_coding.produced_char);
   865               carryover = process_coding.carryover_bytes;
   866               if (carryover > 0)
   867                 memcpy (buf, process_coding.carryover,
   868                         process_coding.carryover_bytes);
   869             }
   870 
   871           if (process_coding.mode & CODING_MODE_LAST_BLOCK)
   872             break;
   873 
   874           /* Make the buffer bigger as we continue to read more data,
   875              but not past CALLPROC_BUFFER_SIZE_MAX.  */
   876           if (bufsize < CALLPROC_BUFFER_SIZE_MAX && total_read > 32 * bufsize)
   877             if ((bufsize *= 2) > CALLPROC_BUFFER_SIZE_MAX)
   878               bufsize = CALLPROC_BUFFER_SIZE_MAX;
   879 
   880           if (display_p)
   881             {
   882               redisplay_preserve_echo_area (1);
   883               /* This variable might have been set to 0 for code
   884                  detection.  In that case, set it back to 1 because
   885                  we should have already detected a coding system.  */
   886               display_on_the_fly = true;
   887             }
   888         }
   889     give_up: ;
   890 
   891       Vlast_coding_system_used = CODING_ID_NAME (process_coding.id);
   892       /* If the caller required, let the buffer inherit the
   893          coding-system used to decode the process output.  */
   894       if (inherit_process_coding_system)
   895         call1 (intern ("after-insert-file-set-buffer-file-coding-system"),
   896                make_fixnum (total_read));
   897     }
   898 
   899   bool wait_ok = true;
   900 #ifndef MSDOS
   901   /* Wait for it to terminate, unless it already has.  */
   902   wait_ok = wait_for_termination (pid, &status, fd0 < 0);
   903 #endif
   904 
   905   /* Don't kill any children that the subprocess may have left behind
   906      when exiting.  */
   907   synch_process_pid = 0;
   908 
   909   SAFE_FREE_UNBIND_TO (count, Qnil);
   910 
   911   if (!wait_ok)
   912     return build_unibyte_string ("internal error");
   913 
   914   if (WIFSIGNALED (status))
   915     {
   916       const char *signame;
   917 
   918       synchronize_system_messages_locale ();
   919       signame = strsignal (WTERMSIG (status));
   920 
   921       if (signame == 0)
   922         signame = "unknown";
   923 
   924       return code_convert_string_norecord (build_string (signame),
   925                                            Vlocale_coding_system, 0);
   926     }
   927 
   928   eassert (WIFEXITED (status));
   929   return make_fixnum (WEXITSTATUS (status));
   930 }
   931 
   932 /* Create a temporary file suitable for storing the input data of
   933    call-process-region.  NARGS and ARGS are the same as for
   934    call-process-region.  Store into *FILENAME_STRING_PTR a Lisp string
   935    naming the file, and return a file descriptor for reading.
   936    Unwind-protect the file, so that the file descriptor will be closed
   937    and the file removed when the caller unwinds the specpdl stack.  */
   938 
   939 static int
   940 create_temp_file (ptrdiff_t nargs, Lisp_Object *args,
   941                   Lisp_Object *filename_string_ptr)
   942 {
   943   int fd;
   944   Lisp_Object filename_string;
   945   Lisp_Object val, start, end;
   946   Lisp_Object tmpdir;
   947 
   948   if (STRINGP (Vtemporary_file_directory))
   949     tmpdir = Vtemporary_file_directory;
   950   else
   951     {
   952       char *outf;
   953 #ifndef DOS_NT
   954       outf = getenv ("TMPDIR");
   955       tmpdir = build_string (outf ? outf : "/tmp/");
   956 #else /* DOS_NT */
   957       if ((outf = egetenv ("TMPDIR"))
   958           || (outf = egetenv ("TMP"))
   959           || (outf = egetenv ("TEMP")))
   960         tmpdir = build_string (outf);
   961       else
   962         tmpdir = Ffile_name_as_directory (build_string ("c:/temp"));
   963 #endif
   964     }
   965 
   966   {
   967     Lisp_Object pattern = Fexpand_file_name (Vtemp_file_name_pattern, tmpdir);
   968     char *tempfile;
   969 
   970 #ifdef WINDOWSNT
   971     /* Cannot use the result of Fexpand_file_name, because it
   972        downcases the XXXXXX part of the pattern, and mktemp then
   973        doesn't recognize it.  */
   974     if (!NILP (Vw32_downcase_file_names))
   975       {
   976         Lisp_Object dirname = Ffile_name_directory (pattern);
   977 
   978         if (NILP (dirname))
   979           pattern = Vtemp_file_name_pattern;
   980         else
   981           pattern = concat2 (dirname, Vtemp_file_name_pattern);
   982       }
   983 #endif
   984 
   985     filename_string = Fcopy_sequence (ENCODE_FILE (pattern));
   986     tempfile = SSDATA (filename_string);
   987 
   988     specpdl_ref count = SPECPDL_INDEX ();
   989     record_unwind_protect_nothing ();
   990     fd = mkostemp (tempfile, O_BINARY | O_CLOEXEC);
   991     if (fd < 0)
   992       report_file_error ("Failed to open temporary file using pattern",
   993                          pattern);
   994     set_unwind_protect (count, delete_temp_file, filename_string);
   995     record_unwind_protect_int (close_file_unwind, fd);
   996   }
   997 
   998   start = args[0];
   999   end = args[1];
  1000   /* Decide coding-system of the contents of the temporary file.  */
  1001   if (!NILP (Vcoding_system_for_write))
  1002     val = Vcoding_system_for_write;
  1003   else if (NILP (BVAR (current_buffer, enable_multibyte_characters)))
  1004     val = Qraw_text;
  1005   else
  1006     {
  1007       Lisp_Object coding_systems;
  1008       Lisp_Object *args2;
  1009       USE_SAFE_ALLOCA;
  1010       SAFE_NALLOCA (args2, 1, nargs + 1);
  1011       args2[0] = Qcall_process_region;
  1012       memcpy (args2 + 1, args, nargs * sizeof *args);
  1013       coding_systems = Ffind_operation_coding_system (nargs + 1, args2);
  1014       val = CONSP (coding_systems) ? XCDR (coding_systems) : Qnil;
  1015       SAFE_FREE ();
  1016     }
  1017   val = complement_process_encoding_system (val);
  1018 
  1019   {
  1020     specpdl_ref count1 = SPECPDL_INDEX ();
  1021 
  1022     specbind (intern ("coding-system-for-write"), val);
  1023     /* POSIX lets mk[s]temp use "."; don't invoke jka-compr if we
  1024        happen to get a ".Z" suffix.  */
  1025     specbind (Qfile_name_handler_alist, Qnil);
  1026     write_region (start, end, filename_string, Qnil, Qlambda, Qnil, Qnil, fd);
  1027 
  1028     unbind_to (count1, Qnil);
  1029   }
  1030 
  1031   if (lseek (fd, 0, SEEK_SET) < 0)
  1032     report_file_error ("Setting file position", filename_string);
  1033 
  1034   /* Note that Fcall_process takes care of binding
  1035      coding-system-for-read.  */
  1036 
  1037   *filename_string_ptr = filename_string;
  1038   return fd;
  1039 }
  1040 
  1041 DEFUN ("call-process-region", Fcall_process_region, Scall_process_region,
  1042        3, MANY, 0,
  1043        doc: /* Send text from START to END to a synchronous process running PROGRAM.
  1044 
  1045 START and END are normally buffer positions specifying the part of the
  1046 buffer to send to the process.
  1047 If START is nil, that means to use the entire buffer contents; END is
  1048 ignored.
  1049 If START is a string, then send that string to the process
  1050 instead of any buffer contents; END is ignored.
  1051 The remaining arguments are optional.
  1052 Delete the text if fourth arg DELETE is non-nil.
  1053 
  1054 Insert output in BUFFER before point; t means current buffer; nil for
  1055  BUFFER means discard it; 0 means discard and don't wait; and `(:file
  1056  FILE)', where FILE is a file name string, means that it should be
  1057  written to that file (if the file already exists it is overwritten).
  1058 BUFFER can be a string which is the name of a buffer.
  1059 BUFFER can also have the form (REAL-BUFFER STDERR-FILE); in that case,
  1060 REAL-BUFFER says what to do with standard output, as above,
  1061 while STDERR-FILE says what to do with standard error in the child.
  1062 STDERR-FILE may be nil (discard standard error output),
  1063 t (mix it with ordinary output), or a file name string.
  1064 
  1065 Sixth arg DISPLAY non-nil means redisplay buffer as output is inserted.
  1066 Remaining arguments ARGS are passed to PROGRAM at startup as command-line
  1067 arguments.
  1068 
  1069 If PROGRAM is not an absolute file name, `call-process-region' will
  1070 look for PROGRAM in `exec-path' (which is a list of directories).
  1071 
  1072 If BUFFER is 0, `call-process-region' returns immediately with value nil.
  1073 Otherwise it waits for PROGRAM to terminate
  1074 and returns a numeric exit status or a signal description string.
  1075 If you quit, the process is killed with SIGINT, or SIGKILL if you quit again.
  1076 
  1077 usage: (call-process-region START END PROGRAM &optional DELETE BUFFER DISPLAY &rest ARGS)  */)
  1078   (ptrdiff_t nargs, Lisp_Object *args)
  1079 {
  1080   Lisp_Object infile, val;
  1081   specpdl_ref count = SPECPDL_INDEX ();
  1082   Lisp_Object start = args[0];
  1083   Lisp_Object end = args[1];
  1084   bool empty_input;
  1085   int fd;
  1086 
  1087   if (STRINGP (start))
  1088     empty_input = SCHARS (start) == 0;
  1089   else if (NILP (start))
  1090     empty_input = BEG == Z;
  1091   else
  1092     {
  1093       validate_region (&args[0], &args[1]);
  1094       start = args[0];
  1095       end = args[1];
  1096       empty_input = XFIXNUM (start) == XFIXNUM (end);
  1097     }
  1098 
  1099   if (!empty_input)
  1100     fd = create_temp_file (nargs, args, &infile);
  1101   else
  1102     {
  1103       infile = Qnil;
  1104       fd = emacs_open (NULL_DEVICE, O_RDONLY, 0);
  1105       if (fd < 0)
  1106         report_file_error ("Opening null device", Qnil);
  1107       record_unwind_protect_int (close_file_unwind, fd);
  1108     }
  1109 
  1110   if (nargs > 3 && !NILP (args[3]))
  1111     {
  1112       if (NILP (start))
  1113         {
  1114           /* No need to save restrictions since we delete everything
  1115              anyway.  */
  1116           labeled_restrictions_remove_in_current_buffer ();
  1117           Fwiden ();
  1118           del_range (BEG, Z);
  1119         }
  1120       else
  1121         Fdelete_region (start, end);
  1122     }
  1123 
  1124   if (nargs > 3)
  1125     {
  1126       args += 2;
  1127       nargs -= 2;
  1128     }
  1129   else
  1130     {
  1131       args[0] = args[2];
  1132       nargs = 2;
  1133     }
  1134   args[1] = infile;
  1135 
  1136   val = call_process (nargs, args, fd,
  1137                       empty_input ? make_invalid_specpdl_ref () : count);
  1138   return unbind_to (count, val);
  1139 }
  1140 
  1141 static char **
  1142 add_env (char **env, char **new_env, char *string)
  1143 {
  1144   char **ep;
  1145   bool ok = 1;
  1146   if (string == NULL)
  1147     return new_env;
  1148 
  1149   /* See if this string duplicates any string already in the env.
  1150      If so, don't put it in.
  1151      When an env var has multiple definitions,
  1152      we keep the definition that comes first in process-environment.  */
  1153   for (ep = env; ok && ep != new_env; ep++)
  1154     {
  1155       char *p = *ep, *q = string;
  1156       while (ok)
  1157         {
  1158           if (*p && *q != *p)
  1159             break;
  1160           if (*q == 0)
  1161             /* The string is a lone variable name; keep it for now, we
  1162                will remove it later.  It is a placeholder for a
  1163                variable that is not to be included in the environment.  */
  1164             break;
  1165           if (*q == '=')
  1166             ok = 0;
  1167           p++, q++;
  1168         }
  1169     }
  1170   if (ok)
  1171     *new_env++ = string;
  1172   return new_env;
  1173 }
  1174 
  1175 #ifndef DOS_NT
  1176 
  1177 /* 'exec' failed inside a child running NAME, with error number ERR.
  1178    Possibly a vforked child needed to allocate a large vector on the
  1179    stack; such a child cannot fall back on malloc because that might
  1180    mess up the allocator's data structures in the parent.
  1181    Report the error and exit the child.  */
  1182 
  1183 static AVOID
  1184 exec_failed (char const *name, int err)
  1185 {
  1186   /* Avoid deadlock if the child's perror writes to a full pipe; the
  1187      pipe's reader is the parent, but with vfork the parent can't
  1188      run until the child exits.  Truncate the diagnostic instead.  */
  1189   fcntl (STDERR_FILENO, F_SETFL, O_NONBLOCK);
  1190 
  1191   errno = err;
  1192   emacs_perror (name);
  1193   _exit (err == ENOENT ? EXIT_ENOENT : EXIT_CANNOT_INVOKE);
  1194 }
  1195 
  1196 #endif
  1197 
  1198 /* This is the last thing run in a newly forked inferior
  1199    either synchronous or asynchronous.
  1200    Copy descriptors IN, OUT and ERR as descriptors 0, 1 and 2.
  1201    Initialize inferior's priority, pgrp, connected dir and environment.
  1202    then exec another program based on new_argv.
  1203 
  1204    CURRENT_DIR is an elisp string giving the path of the current
  1205    directory the subprocess should have.  Since we can't really signal
  1206    a decent error from within the child, this should be verified as an
  1207    executable directory by the parent.
  1208 
  1209    On GNUish hosts, either exec or return an error number.
  1210    On MS-Windows, either return a pid or return -1 and set errno.
  1211    On MS-DOS, either return an exit status or signal an error.  */
  1212 
  1213 static CHILD_SETUP_TYPE
  1214 child_setup (int in, int out, int err, char **new_argv, char **env,
  1215              const char *current_dir)
  1216 {
  1217 #ifdef MSDOS
  1218   char *pwd_var;
  1219   char *temp;
  1220   ptrdiff_t i;
  1221 #endif
  1222 #ifdef WINDOWSNT
  1223   int cpid;
  1224   HANDLE handles[3];
  1225 #else
  1226   pid_t pid = getpid ();
  1227 #endif /* WINDOWSNT */
  1228 
  1229   /* Note that use of alloca is always safe here.  It's obvious for systems
  1230      that do not have true vfork or that have true (stack) alloca.
  1231      If using vfork and C_ALLOCA (when Emacs used to include
  1232      src/alloca.c) it is safe because that changes the superior's
  1233      static variables as if the superior had done alloca and will be
  1234      cleaned up in the usual way. */
  1235 
  1236 #ifndef DOS_NT
  1237     /* We can't signal an Elisp error here; we're in a vfork.  Since
  1238        the callers check the current directory before forking, this
  1239        should only return an error if the directory's permissions
  1240        are changed between the check and this chdir, but we should
  1241        at least check.  */
  1242     if (chdir (current_dir) < 0)
  1243       _exit (EXIT_CANCELED);
  1244 #endif
  1245 
  1246 #ifdef WINDOWSNT
  1247   prepare_standard_handles (in, out, err, handles);
  1248   set_process_dir (current_dir);
  1249   /* Spawn the child.  (See w32proc.c:sys_spawnve).  */
  1250   cpid = spawnve (_P_NOWAIT, new_argv[0], new_argv, env);
  1251   reset_standard_handles (in, out, err, handles);
  1252   return cpid;
  1253 
  1254 #else  /* not WINDOWSNT */
  1255 
  1256 #ifndef MSDOS
  1257 
  1258   restore_nofile_limit ();
  1259 
  1260   /* Redirect file descriptors and clear the close-on-exec flag on the
  1261      redirected ones.  IN, OUT, and ERR are close-on-exec so they
  1262      need not be closed explicitly.  */
  1263   dup2 (in, STDIN_FILENO);
  1264   dup2 (out, STDOUT_FILENO);
  1265   dup2 (err, STDERR_FILENO);
  1266 
  1267   setpgid (0, 0);
  1268   tcsetpgrp (0, pid);
  1269 
  1270   int errnum = emacs_exec_file (new_argv[0], new_argv, env);
  1271   exec_failed (new_argv[0], errnum);
  1272 
  1273 #else /* MSDOS */
  1274   i = strlen (current_dir);
  1275   pwd_var = xmalloc (i + 5);
  1276   temp = pwd_var + 4;
  1277   memcpy (pwd_var, "PWD=", 4);
  1278   stpcpy (temp, current_dir);
  1279 
  1280   if (i > 2 && IS_DEVICE_SEP (temp[1]) && IS_DIRECTORY_SEP (temp[2]))
  1281     {
  1282       temp += 2;
  1283       i -= 2;
  1284     }
  1285 
  1286   /* Strip trailing slashes for PWD, but leave "/" and "//" alone.  */
  1287   while (i > 2 && IS_DIRECTORY_SEP (temp[i - 1]))
  1288     temp[--i] = 0;
  1289 
  1290   pid = run_msdos_command (new_argv, pwd_var + 4, in, out, err, env);
  1291   xfree (pwd_var);
  1292   if (pid == -1)
  1293     /* An error occurred while trying to run the subprocess.  */
  1294     report_file_error ("Spawning child process", Qnil);
  1295   return pid;
  1296 #endif  /* MSDOS */
  1297 #endif  /* not WINDOWSNT */
  1298 }
  1299 
  1300 #if USABLE_POSIX_SPAWN
  1301 
  1302 /* Set up ACTIONS and ATTRIBUTES for `posix_spawn'.  Return an error
  1303    number.  */
  1304 
  1305 static int
  1306 emacs_posix_spawn_init_actions (posix_spawn_file_actions_t *actions,
  1307                                 int std_in, int std_out, int std_err,
  1308                                 const char *cwd)
  1309 {
  1310   int error = posix_spawn_file_actions_init (actions);
  1311   if (error != 0)
  1312     return error;
  1313 
  1314   error = posix_spawn_file_actions_adddup2 (actions, std_in,
  1315                                             STDIN_FILENO);
  1316   if (error != 0)
  1317     goto out;
  1318 
  1319   error = posix_spawn_file_actions_adddup2 (actions, std_out,
  1320                                             STDOUT_FILENO);
  1321   if (error != 0)
  1322     goto out;
  1323 
  1324   error = posix_spawn_file_actions_adddup2 (actions,
  1325                                             std_err < 0 ? std_out
  1326                                                         : std_err,
  1327                                             STDERR_FILENO);
  1328   if (error != 0)
  1329     goto out;
  1330 
  1331   /* Haiku appears to have linkable posix_spawn_file_actions_chdir,
  1332      but it always fails.  So use the _np function instead.  */
  1333 #if defined HAVE_POSIX_SPAWN_FILE_ACTIONS_ADDCHDIR && !defined HAIKU
  1334   error = posix_spawn_file_actions_addchdir (actions, cwd);
  1335 #else
  1336   error = posix_spawn_file_actions_addchdir_np (actions, cwd);
  1337 #endif
  1338   if (error != 0)
  1339     goto out;
  1340 
  1341  out:
  1342   if (error != 0)
  1343     posix_spawn_file_actions_destroy (actions);
  1344   return error;
  1345 }
  1346 
  1347 static int
  1348 emacs_posix_spawn_init_attributes (posix_spawnattr_t *attributes,
  1349                                    const sigset_t *oldset)
  1350 {
  1351   int error = posix_spawnattr_init (attributes);
  1352   if (error != 0)
  1353     return error;
  1354 
  1355   error = posix_spawnattr_setflags (attributes,
  1356                                     POSIX_SPAWN_SETSID
  1357                                     | POSIX_SPAWN_SETSIGDEF
  1358                                     | POSIX_SPAWN_SETSIGMASK);
  1359   if (error != 0)
  1360     goto out;
  1361 
  1362   sigset_t sigdefault;
  1363   sigemptyset (&sigdefault);
  1364 
  1365 #ifdef DARWIN_OS
  1366   /* Work around a macOS bug, where SIGCHLD is apparently
  1367      delivered to a vforked child instead of to its parent.  See:
  1368      https://lists.gnu.org/r/emacs-devel/2017-05/msg00342.html
  1369   */
  1370   sigaddset (&sigdefault, SIGCHLD);
  1371 #endif
  1372 
  1373   sigaddset (&sigdefault, SIGINT);
  1374   sigaddset (&sigdefault, SIGQUIT);
  1375 #ifdef SIGPROF
  1376   sigaddset (&sigdefault, SIGPROF);
  1377 #endif
  1378 
  1379   /* Emacs ignores SIGPIPE, but the child should not.  */
  1380   sigaddset (&sigdefault, SIGPIPE);
  1381   /* Likewise for SIGPROF.  */
  1382 #ifdef SIGPROF
  1383   sigaddset (&sigdefault, SIGPROF);
  1384 #endif
  1385 
  1386   error = posix_spawnattr_setsigdefault (attributes, &sigdefault);
  1387   if (error != 0)
  1388     goto out;
  1389 
  1390   /* Stop blocking SIGCHLD in the child.  */
  1391   error = posix_spawnattr_setsigmask (attributes, oldset);
  1392   if (error != 0)
  1393     goto out;
  1394 
  1395  out:
  1396   if (error != 0)
  1397     posix_spawnattr_destroy (attributes);
  1398 
  1399   return error;
  1400 }
  1401 
  1402 #endif
  1403 
  1404 /* Start a new asynchronous subprocess.  If successful, return zero
  1405    and store the process identifier of the new process in *NEWPID.
  1406    Use STDIN, STDOUT, and STDERR as standard streams for the new
  1407    process.  Use ARGV as argument vector for the new process; use
  1408    process image file ARGV[0].  Use ENVP for the environment block for
  1409    the new process.  Use CWD as working directory for the new process.
  1410    If PTY is not NULL, it must be a pseudoterminal device.  If PTY is
  1411    NULL, don't perform any terminal setup.  OLDSET must be a pointer
  1412    to a signal set initialized by `block_child_signal'.  Before
  1413    calling this function, call `block_input' and `block_child_signal';
  1414    afterwards, call `unblock_input' and `unblock_child_signal'.  Be
  1415    sure to call `unblock_child_signal' only after registering NEWPID
  1416    in a list where `handle_child_signal' can find it!  */
  1417 
  1418 int
  1419 emacs_spawn (pid_t *newpid, int std_in, int std_out, int std_err,
  1420              char **argv, char **envp, const char *cwd,
  1421              const char *pty_name, bool pty_in, bool pty_out,
  1422              const sigset_t *oldset)
  1423 {
  1424 #if USABLE_POSIX_SPAWN
  1425   /* Prefer the simpler `posix_spawn' if available.  `posix_spawn'
  1426      doesn't yet support setting up pseudoterminals, so we fall back
  1427      to `vfork' if we're supposed to use a pseudoterminal.  */
  1428 
  1429   bool use_posix_spawn = pty_name == NULL;
  1430 
  1431   posix_spawn_file_actions_t actions;
  1432   posix_spawnattr_t attributes;
  1433 
  1434   if (use_posix_spawn)
  1435     {
  1436       /* Initialize optional attributes before blocking. */
  1437       int error = emacs_posix_spawn_init_actions (&actions, std_in,
  1438                                               std_out, std_err, cwd);
  1439       if (error != 0)
  1440         return error;
  1441 
  1442       error = emacs_posix_spawn_init_attributes (&attributes, oldset);
  1443       if (error != 0)
  1444         return error;
  1445     }
  1446 #endif
  1447 
  1448   int pid;
  1449   int vfork_error;
  1450 
  1451   eassert (input_blocked_p ());
  1452 
  1453 #if USABLE_POSIX_SPAWN
  1454   if (use_posix_spawn)
  1455     {
  1456       vfork_error = posix_spawn (&pid, argv[0], &actions, &attributes,
  1457                                  argv, envp);
  1458       if (vfork_error != 0)
  1459         pid = -1;
  1460 
  1461       int error = posix_spawn_file_actions_destroy (&actions);
  1462       if (error != 0)
  1463         {
  1464           errno = error;
  1465           emacs_perror ("posix_spawn_file_actions_destroy");
  1466         }
  1467 
  1468       error = posix_spawnattr_destroy (&attributes);
  1469       if (error != 0)
  1470         {
  1471           errno = error;
  1472           emacs_perror ("posix_spawnattr_destroy");
  1473         }
  1474 
  1475       goto fork_done;
  1476     }
  1477 #endif
  1478 
  1479 #ifndef WINDOWSNT
  1480   /* vfork, and prevent local vars from being clobbered by the vfork.  */
  1481   pid_t *volatile newpid_volatile = newpid;
  1482   const char *volatile cwd_volatile = cwd;
  1483   const char *volatile ptyname_volatile = pty_name;
  1484   bool volatile ptyin_volatile = pty_in;
  1485   bool volatile ptyout_volatile = pty_out;
  1486   char **volatile argv_volatile = argv;
  1487   int volatile stdin_volatile = std_in;
  1488   int volatile stdout_volatile = std_out;
  1489   int volatile stderr_volatile = std_err;
  1490   char **volatile envp_volatile = envp;
  1491   const sigset_t *volatile oldset_volatile = oldset;
  1492 
  1493 #ifdef DARWIN_OS
  1494   /* Darwin doesn't let us run setsid after a vfork, so use fork when
  1495      necessary.  Below, we reset SIGCHLD handling after a vfork, as
  1496      apparently macOS can mistakenly deliver SIGCHLD to the child.  */
  1497   if (pty_in || pty_out)
  1498     pid = fork ();
  1499   else
  1500     pid = VFORK ();
  1501 #else
  1502   pid = vfork ();
  1503 #endif
  1504 
  1505   newpid = newpid_volatile;
  1506   cwd = cwd_volatile;
  1507   pty_name = ptyname_volatile;
  1508   pty_in = ptyin_volatile;
  1509   pty_out = ptyout_volatile;
  1510   argv = argv_volatile;
  1511   std_in = stdin_volatile;
  1512   std_out = stdout_volatile;
  1513   std_err = stderr_volatile;
  1514   envp = envp_volatile;
  1515   oldset = oldset_volatile;
  1516 
  1517   if (pid == 0)
  1518 #endif /* not WINDOWSNT */
  1519     {
  1520       /* Make the pty be the controlling terminal of the process.  */
  1521 #ifdef HAVE_PTYS
  1522       dissociate_controlling_tty ();
  1523 
  1524       /* Make the pty's terminal the controlling terminal.  */
  1525       if (pty_in && std_in >= 0)
  1526         {
  1527 #ifdef TIOCSCTTY
  1528           /* We ignore the return value
  1529              because faith@cs.unc.edu says that is necessary on Linux.  */
  1530           ioctl (std_in, TIOCSCTTY, 0);
  1531 #endif
  1532         }
  1533 #if defined (LDISC1)
  1534       if (pty_in && std_in >= 0)
  1535         {
  1536           struct termios t;
  1537           tcgetattr (std_in, &t);
  1538           t.c_lflag = LDISC1;
  1539           if (tcsetattr (std_in, TCSANOW, &t) < 0)
  1540             emacs_perror ("create_process/tcsetattr LDISC1");
  1541         }
  1542 #else
  1543 #if defined (NTTYDISC) && defined (TIOCSETD)
  1544       if (pty_in && std_in >= 0)
  1545         {
  1546           /* Use new line discipline.  */
  1547           int ldisc = NTTYDISC;
  1548           ioctl (std_in, TIOCSETD, &ldisc);
  1549         }
  1550 #endif
  1551 #endif
  1552 
  1553 #if !defined (DONT_REOPEN_PTY)
  1554 /*** There is a suggestion that this ought to be a
  1555      conditional on TIOCSPGRP, or !defined TIOCSCTTY.
  1556      Trying the latter gave the wrong results on Debian GNU/Linux 1.1;
  1557      that system does seem to need this code, even though
  1558      both TIOCSCTTY is defined.  */
  1559         /* Now close the pty (if we had it open) and reopen it.
  1560            This makes the pty the controlling terminal of the subprocess.  */
  1561       if (pty_name)
  1562         {
  1563 
  1564           /* I wonder if emacs_close (emacs_open (pty, ...))
  1565              would work?  */
  1566           if (pty_in && std_in >= 0)
  1567             emacs_close (std_in);
  1568           int ptyfd = emacs_open_noquit (pty_name, O_RDWR, 0);
  1569           if (pty_in)
  1570             std_in = ptyfd;
  1571           if (pty_out)
  1572             std_out = ptyfd;
  1573           if (std_in < 0)
  1574             {
  1575               emacs_perror (pty_name);
  1576               _exit (EXIT_CANCELED);
  1577             }
  1578 
  1579         }
  1580 #endif /* not DONT_REOPEN_PTY */
  1581 
  1582 #ifdef SETUP_SLAVE_PTY
  1583       if (pty_in && std_in >= 0)
  1584         {
  1585           SETUP_SLAVE_PTY;
  1586         }
  1587 #endif /* SETUP_SLAVE_PTY */
  1588 #endif /* HAVE_PTYS */
  1589 
  1590 #ifdef DARWIN_OS
  1591       /* Work around a macOS bug, where SIGCHLD is apparently
  1592          delivered to a vforked child instead of to its parent.  See:
  1593          https://lists.gnu.org/r/emacs-devel/2017-05/msg00342.html
  1594       */
  1595       signal (SIGCHLD, SIG_DFL);
  1596 #endif
  1597 
  1598       signal (SIGINT, SIG_DFL);
  1599       signal (SIGQUIT, SIG_DFL);
  1600 #ifdef SIGPROF
  1601       signal (SIGPROF, SIG_DFL);
  1602 #endif
  1603 
  1604       /* Emacs ignores SIGPIPE, but the child should not.  */
  1605       signal (SIGPIPE, SIG_DFL);
  1606       /* Likewise for SIGPROF.  */
  1607 #ifdef SIGPROF
  1608       signal (SIGPROF, SIG_DFL);
  1609 #endif
  1610 
  1611 #ifdef subprocesses
  1612       /* Stop blocking SIGCHLD in the child.  */
  1613       unblock_child_signal (oldset);
  1614 
  1615       if (pty_out)
  1616         child_setup_tty (std_out);
  1617 #endif
  1618 
  1619       if (std_err < 0)
  1620         std_err = std_out;
  1621 #ifdef WINDOWSNT
  1622       pid = child_setup (std_in, std_out, std_err, argv, envp, cwd);
  1623 #else  /* not WINDOWSNT */
  1624       child_setup (std_in, std_out, std_err, argv, envp, cwd);
  1625 #endif /* not WINDOWSNT */
  1626     }
  1627 
  1628   /* Back in the parent process.  */
  1629 
  1630   vfork_error = pid < 0 ? errno : 0;
  1631 
  1632 #if USABLE_POSIX_SPAWN
  1633  fork_done:
  1634 #endif
  1635   if (pid < 0)
  1636     {
  1637       eassert (0 < vfork_error);
  1638       return vfork_error;
  1639     }
  1640 
  1641   eassert (0 < pid);
  1642   *newpid = pid;
  1643   return 0;
  1644 }
  1645 
  1646 static bool
  1647 getenv_internal_1 (const char *var, ptrdiff_t varlen, char **value,
  1648                    ptrdiff_t *valuelen, Lisp_Object env)
  1649 {
  1650   for (; CONSP (env); env = XCDR (env))
  1651     {
  1652       Lisp_Object entry = XCAR (env);
  1653       if (STRINGP (entry)
  1654           && SBYTES (entry) >= varlen
  1655 #ifdef WINDOWSNT
  1656           /* NT environment variables are case insensitive.  */
  1657           && ! strnicmp (SSDATA (entry), var, varlen)
  1658 #else  /* not WINDOWSNT */
  1659           && ! memcmp (SDATA (entry), var, varlen)
  1660 #endif /* not WINDOWSNT */
  1661           )
  1662         {
  1663           if (SBYTES (entry) > varlen && SREF (entry, varlen) == '=')
  1664             {
  1665               *value = SSDATA (entry) + (varlen + 1);
  1666               *valuelen = SBYTES (entry) - (varlen + 1);
  1667               return 1;
  1668             }
  1669           else if (SBYTES (entry) == varlen)
  1670             {
  1671               /* Lone variable names in Vprocess_environment mean that
  1672                  variable should be removed from the environment. */
  1673               *value = NULL;
  1674               return 1;
  1675             }
  1676         }
  1677     }
  1678   return 0;
  1679 }
  1680 
  1681 static bool
  1682 getenv_internal (const char *var, ptrdiff_t varlen, char **value,
  1683                  ptrdiff_t *valuelen, Lisp_Object frame)
  1684 {
  1685   /* Try to find VAR in Vprocess_environment first.  */
  1686   if (getenv_internal_1 (var, varlen, value, valuelen,
  1687                          Vprocess_environment))
  1688     return *value ? 1 : 0;
  1689 
  1690   /* On Windows we make some modifications to Emacs' environment
  1691      without recording them in Vprocess_environment.  */
  1692 #ifdef WINDOWSNT
  1693   {
  1694     char *tmpval = getenv (var);
  1695     if (tmpval)
  1696       {
  1697         *value = tmpval;
  1698         *valuelen = strlen (tmpval);
  1699         return 1;
  1700       }
  1701   }
  1702 #endif
  1703 
  1704   /* For DISPLAY try to get the values from the frame or the initial env.  */
  1705   if (strcmp (var, "DISPLAY") == 0)
  1706     {
  1707 #ifndef HAVE_PGTK
  1708       Lisp_Object display
  1709         = Fframe_parameter (NILP (frame) ? selected_frame : frame, Qdisplay);
  1710       if (STRINGP (display))
  1711         {
  1712           *value    = SSDATA (display);
  1713           *valuelen = SBYTES (display);
  1714           return 1;
  1715         }
  1716 #endif
  1717       /* If still not found, Look for DISPLAY in Vinitial_environment.  */
  1718       if (getenv_internal_1 (var, varlen, value, valuelen,
  1719                              Vinitial_environment))
  1720         return *value ? 1 : 0;
  1721     }
  1722 
  1723   return 0;
  1724 }
  1725 
  1726 DEFUN ("getenv-internal", Fgetenv_internal, Sgetenv_internal, 1, 2, 0,
  1727        doc: /* Get the value of environment variable VARIABLE.
  1728 VARIABLE should be a string.  Value is nil if VARIABLE is undefined in
  1729 the environment.  Otherwise, value is a string.
  1730 
  1731 This function searches `process-environment' for VARIABLE.
  1732 
  1733 If optional parameter ENV is a list, then search this list instead of
  1734 `process-environment', and return t when encountering a negative entry
  1735 \(an entry for a variable with no value).  */)
  1736   (Lisp_Object variable, Lisp_Object env)
  1737 {
  1738   char *value;
  1739   ptrdiff_t valuelen;
  1740 
  1741   CHECK_STRING (variable);
  1742   if (CONSP (env))
  1743     {
  1744       if (getenv_internal_1 (SSDATA (variable), SBYTES (variable),
  1745                              &value, &valuelen, env))
  1746         return value ? make_string (value, valuelen) : Qt;
  1747       else
  1748         return Qnil;
  1749     }
  1750   else if (getenv_internal (SSDATA (variable), SBYTES (variable),
  1751                             &value, &valuelen, env))
  1752     return make_string (value, valuelen);
  1753   else
  1754     return Qnil;
  1755 }
  1756 
  1757 /* A version of getenv that consults the Lisp environment lists,
  1758    easily callable from C.  This is usually called from egetenv.  */
  1759 char *
  1760 egetenv_internal (const char *var, ptrdiff_t len)
  1761 {
  1762   char *value;
  1763   ptrdiff_t valuelen;
  1764 
  1765   if (getenv_internal (var, len, &value, &valuelen, Qnil))
  1766     return value;
  1767   else
  1768     return 0;
  1769 }
  1770 
  1771 /* Create a new environment block.  You can pass the returned pointer
  1772    to `execve'.  Add unwind protections for all newly-allocated
  1773    objects.  Don't call any Lisp code or the garbage collector while
  1774    the block is active.  */
  1775 
  1776 char **
  1777 make_environment_block (Lisp_Object current_dir)
  1778 {
  1779   char **env;
  1780   char *pwd_var;
  1781 
  1782   {
  1783     char *temp;
  1784     ptrdiff_t i;
  1785 
  1786     i = SBYTES (current_dir);
  1787     pwd_var = xmalloc (i + 5);
  1788     record_unwind_protect_ptr (xfree, pwd_var);
  1789     temp = pwd_var + 4;
  1790     memcpy (pwd_var, "PWD=", 4);
  1791     lispstpcpy (temp, current_dir);
  1792 
  1793 #ifdef DOS_NT
  1794     /* Get past the drive letter, so that d:/ is left alone.  */
  1795     if (i > 2 && IS_DEVICE_SEP (temp[1]) && IS_DIRECTORY_SEP (temp[2]))
  1796       {
  1797         temp += 2;
  1798         i -= 2;
  1799       }
  1800 #endif /* DOS_NT */
  1801 
  1802     /* Strip trailing slashes for PWD, but leave "/" and "//" alone.  */
  1803     while (i > 2 && IS_DIRECTORY_SEP (temp[i - 1]))
  1804       temp[--i] = 0;
  1805   }
  1806 
  1807   /* Set `env' to a vector of the strings in the environment.  */
  1808 
  1809   {
  1810     register Lisp_Object tem;
  1811     register char **new_env;
  1812     char **p, **q;
  1813     register int new_length;
  1814     Lisp_Object display = Qnil;
  1815 
  1816     new_length = 0;
  1817 
  1818     for (tem = Vprocess_environment;
  1819          CONSP (tem) && STRINGP (XCAR (tem));
  1820          tem = XCDR (tem))
  1821       {
  1822         if (strncmp (SSDATA (XCAR (tem)), "DISPLAY", 7) == 0
  1823             && (SDATA (XCAR (tem)) [7] == '\0'
  1824                 || SDATA (XCAR (tem)) [7] == '='))
  1825           /* DISPLAY is specified in process-environment.  */
  1826           display = Qt;
  1827         new_length++;
  1828       }
  1829 
  1830     /* If not provided yet, use the frame's DISPLAY.  */
  1831     if (NILP (display))
  1832       {
  1833         Lisp_Object tmp = Fframe_parameter (selected_frame, Qdisplay);
  1834 
  1835 #ifdef HAVE_PGTK
  1836         /* The only time GDK actually returns correct information is
  1837            when it's running under X Windows.  DISPLAY shouldn't be
  1838            set to a Wayland display either, since that's an X specific
  1839            variable.  */
  1840         if (FRAME_WINDOW_P (SELECTED_FRAME ())
  1841             && strcmp (G_OBJECT_TYPE_NAME (FRAME_X_DISPLAY (SELECTED_FRAME ())),
  1842                        "GdkX11Display"))
  1843           tmp = Qnil;
  1844 #endif
  1845 
  1846         if (!STRINGP (tmp) && CONSP (Vinitial_environment))
  1847           /* If still not found, Look for DISPLAY in Vinitial_environment.  */
  1848           tmp = Fgetenv_internal (build_string ("DISPLAY"),
  1849                                   Vinitial_environment);
  1850         if (STRINGP (tmp))
  1851           {
  1852             display = tmp;
  1853             new_length++;
  1854           }
  1855       }
  1856 
  1857     /* new_length + 2 to include PWD and terminating 0.  */
  1858     env = new_env = xnmalloc (new_length + 2, sizeof *env);
  1859     record_unwind_protect_ptr (xfree, env);
  1860     /* If we have a PWD envvar, pass one down,
  1861        but with corrected value.  */
  1862     if (egetenv ("PWD"))
  1863       *new_env++ = pwd_var;
  1864 
  1865     if (STRINGP (display))
  1866       {
  1867         char *vdata = xmalloc (sizeof "DISPLAY=" + SBYTES (display));
  1868         record_unwind_protect_ptr (xfree, vdata);
  1869         lispstpcpy (stpcpy (vdata, "DISPLAY="), display);
  1870         new_env = add_env (env, new_env, vdata);
  1871       }
  1872 
  1873     /* Overrides.  */
  1874     for (tem = Vprocess_environment;
  1875          CONSP (tem) && STRINGP (XCAR (tem));
  1876          tem = XCDR (tem))
  1877       new_env = add_env (env, new_env, SSDATA (XCAR (tem)));
  1878 
  1879     *new_env = 0;
  1880 
  1881     /* Remove variable names without values.  */
  1882     p = q = env;
  1883     while (*p != 0)
  1884       {
  1885         while (*q != 0 && strchr (*q, '=') == NULL)
  1886           q++;
  1887         *p = *q++;
  1888         if (*p != 0)
  1889           p++;
  1890       }
  1891   }
  1892 
  1893   return env;
  1894 }
  1895 
  1896 
  1897 /* This is run before init_cmdargs.  */
  1898 
  1899 void
  1900 init_callproc_1 (void)
  1901 {
  1902   Vdata_directory = decode_env_path ("EMACSDATA", PATH_DATA, 0);
  1903   Vdata_directory = Ffile_name_as_directory (Fcar (Vdata_directory));
  1904 
  1905   Vdoc_directory = decode_env_path ("EMACSDOC", PATH_DOC, 0);
  1906   Vdoc_directory = Ffile_name_as_directory (Fcar (Vdoc_directory));
  1907 
  1908   /* Check the EMACSPATH environment variable, defaulting to the
  1909      PATH_EXEC path from epaths.h.  */
  1910   Vexec_path = decode_env_path ("EMACSPATH", PATH_EXEC, 0);
  1911   Vexec_directory = Ffile_name_as_directory (Fcar (Vexec_path));
  1912   /* FIXME?  For ns, path_exec should go at the front?  */
  1913   Vexec_path = nconc2 (decode_env_path ("PATH", "", 0), Vexec_path);
  1914 }
  1915 
  1916 /* This is run after init_cmdargs, when Vinstallation_directory is valid.  */
  1917 
  1918 void
  1919 init_callproc (void)
  1920 {
  1921   bool data_dir = egetenv ("EMACSDATA") != 0;
  1922 
  1923   char *sh;
  1924   Lisp_Object tempdir;
  1925 
  1926   if (!NILP (Vinstallation_directory))
  1927     {
  1928       /* Add to the path the lib-src subdir of the installation dir.  */
  1929       Lisp_Object tem;
  1930       tem = Fexpand_file_name (build_string ("lib-src"),
  1931                                Vinstallation_directory);
  1932 #ifndef MSDOS
  1933           /* MSDOS uses wrapped binaries, so don't do this.  */
  1934       if (NILP (Fmember (tem, Vexec_path)))
  1935         {
  1936           /* Running uninstalled, so default to tem rather than PATH_EXEC.  */
  1937           Vexec_path = decode_env_path ("EMACSPATH", SSDATA (tem), 0);
  1938           Vexec_path = nconc2 (decode_env_path ("PATH", "", 0), Vexec_path);
  1939         }
  1940 
  1941       Vexec_directory = Ffile_name_as_directory (tem);
  1942 #endif /* not MSDOS */
  1943 
  1944       /* Maybe use ../etc as well as ../lib-src.  */
  1945       if (data_dir == 0)
  1946         {
  1947           tem = Fexpand_file_name (build_string ("etc"),
  1948                                    Vinstallation_directory);
  1949           Vdoc_directory = Ffile_name_as_directory (tem);
  1950         }
  1951     }
  1952 
  1953   /* Look for the files that should be in etc.  We don't use
  1954      Vinstallation_directory, because these files are never installed
  1955      near the executable, and they are never in the build
  1956      directory when that's different from the source directory.
  1957 
  1958      Instead, if these files are not in the nominal place, we try the
  1959      source directory.  */
  1960   if (data_dir == 0)
  1961     {
  1962       Lisp_Object tem, srcdir;
  1963       Lisp_Object lispdir = Fcar (decode_env_path (0, PATH_DUMPLOADSEARCH, 0));
  1964 
  1965       srcdir = Fexpand_file_name (build_string ("../src/"), lispdir);
  1966 
  1967       tem = Fexpand_file_name (build_string ("NEWS"), Vdata_directory);
  1968       if (!NILP (Fequal (srcdir, Vinvocation_directory))
  1969           || NILP (Ffile_exists_p (tem)) || !NILP (Vinstallation_directory))
  1970         {
  1971           Lisp_Object newdir;
  1972           newdir = Fexpand_file_name (build_string ("../etc/"), lispdir);
  1973           tem = Fexpand_file_name (build_string ("NEWS"), newdir);
  1974           if (!NILP (Ffile_exists_p (tem)))
  1975             Vdata_directory = newdir;
  1976         }
  1977     }
  1978 
  1979   if (!will_dump_p ())
  1980     {
  1981       tempdir = Fdirectory_file_name (Vexec_directory);
  1982       if (! file_accessible_directory_p (tempdir))
  1983         dir_warning ("arch-dependent data dir", Vexec_directory);
  1984     }
  1985 
  1986   tempdir = Fdirectory_file_name (Vdata_directory);
  1987   if (! file_accessible_directory_p (tempdir))
  1988     dir_warning ("arch-independent data dir", Vdata_directory);
  1989 
  1990   sh = getenv ("SHELL");
  1991   Vshell_file_name = build_string (sh ? sh : "/bin/sh");
  1992 
  1993   Lisp_Object gamedir = Qnil;
  1994   if (PATH_GAME)
  1995     {
  1996       const char *cpath_game = PATH_GAME;
  1997 #ifdef WINDOWSNT
  1998       /* On MS-Windows, PATH_GAME normally starts with a literal
  1999          "%emacs_dir%", so it will never work without some tweaking.  */
  2000       cpath_game = w32_relocate (cpath_game);
  2001 #endif
  2002       Lisp_Object path_game = build_unibyte_string (cpath_game);
  2003       if (file_accessible_directory_p (path_game))
  2004         gamedir = path_game;
  2005       else if (errno != ENOENT && errno != ENOTDIR
  2006 #ifdef DOS_NT
  2007                /* DOS/Windows sometimes return EACCES for bad file names  */
  2008                && errno != EACCES
  2009 #endif
  2010                )
  2011         dir_warning ("game dir", path_game);
  2012     }
  2013   Vshared_game_score_directory = gamedir;
  2014 }
  2015 
  2016 void
  2017 set_initial_environment (void)
  2018 {
  2019   char **envp;
  2020   for (envp = environ; *envp; envp++)
  2021     Vprocess_environment = Fcons (build_string (*envp),
  2022                                   Vprocess_environment);
  2023   /* Ideally, the `copy' shouldn't be necessary, but it seems it's frequent
  2024      to use `delete' and friends on process-environment.  */
  2025   Vinitial_environment = Fcopy_sequence (Vprocess_environment);
  2026 }
  2027 
  2028 void
  2029 syms_of_callproc (void)
  2030 {
  2031 #ifndef DOS_NT
  2032   Vtemp_file_name_pattern = build_string ("emacsXXXXXX");
  2033 #else  /* DOS_NT */
  2034   Vtemp_file_name_pattern = build_string ("emXXXXXX");
  2035 #endif
  2036   staticpro (&Vtemp_file_name_pattern);
  2037 
  2038 #ifdef MSDOS
  2039   synch_process_tempfile = make_fixnum (0);
  2040   staticpro (&synch_process_tempfile);
  2041 #endif
  2042 
  2043   DEFVAR_LISP ("shell-file-name", Vshell_file_name,
  2044                doc: /* File name to load inferior shells from.
  2045 Initialized from the SHELL environment variable, or to a system-dependent
  2046 default if SHELL is unset.  See Info node `(elisp)Security Considerations'.  */);
  2047 
  2048   DEFVAR_LISP ("exec-path", Vexec_path,
  2049                doc: /* List of directories to search programs to run in subprocesses.
  2050 Each element is a string (directory name) or nil (try default directory).
  2051 
  2052 By default the last element of this list is `exec-directory'. The
  2053 last element is not always used, for example in shell completion
  2054 \(`shell-dynamic-complete-command').  */);
  2055 
  2056   DEFVAR_LISP ("exec-suffixes", Vexec_suffixes,
  2057                doc: /* List of suffixes to try to find executable file names.
  2058 Each element is a string.  */);
  2059   Vexec_suffixes = Qnil;
  2060 
  2061   DEFVAR_LISP ("exec-directory", Vexec_directory,
  2062                doc: /* Directory for executables for Emacs to invoke.
  2063 More generally, this includes any architecture-dependent files
  2064 that are built and installed from the Emacs distribution.  */);
  2065 
  2066   DEFVAR_LISP ("data-directory", Vdata_directory,
  2067                doc: /* Directory of machine-independent files that come with GNU Emacs.
  2068 These are files intended for Emacs to use while it runs.  */);
  2069 
  2070   DEFVAR_LISP ("doc-directory", Vdoc_directory,
  2071                doc: /* Directory containing the DOC file that comes with GNU Emacs.
  2072 This is usually the same as `data-directory'.  */);
  2073 
  2074   DEFVAR_LISP ("configure-info-directory", Vconfigure_info_directory,
  2075                doc: /* For internal use by the build procedure only.
  2076 This is the name of the directory in which the build procedure installed
  2077 Emacs's info files; the default value for `Info-default-directory-list'
  2078 includes this.  */);
  2079   Vconfigure_info_directory = build_string (PATH_INFO);
  2080 
  2081   DEFVAR_LISP ("shared-game-score-directory", Vshared_game_score_directory,
  2082                doc: /* Directory of score files for games which come with GNU Emacs.
  2083 If this variable is nil, then Emacs is unable to use a shared directory.  */);
  2084 
  2085   DEFVAR_LISP ("initial-environment", Vinitial_environment,
  2086                doc: /* List of environment variables inherited from the parent process.
  2087 Each element should be a string of the form ENVVARNAME=VALUE.
  2088 The elements must normally be decoded (using `locale-coding-system') for use.  */);
  2089   Vinitial_environment = Qnil;
  2090 
  2091   DEFVAR_LISP ("process-environment", Vprocess_environment,
  2092                doc: /* List of overridden environment variables for subprocesses to inherit.
  2093 Each element should be a string of the form ENVVARNAME=VALUE.
  2094 
  2095 Entries in this list take precedence to those in the frame-local
  2096 environments.  Therefore, let-binding `process-environment' is an easy
  2097 way to temporarily change the value of an environment variable,
  2098 irrespective of where it comes from.  To use `process-environment' to
  2099 remove an environment variable, include only its name in the list,
  2100 without "=VALUE".
  2101 
  2102 This variable is set to nil when Emacs starts.
  2103 
  2104 If multiple entries define the same variable, the first one always
  2105 takes precedence.
  2106 
  2107 Non-ASCII characters are encoded according to the initial value of
  2108 `locale-coding-system', i.e. the elements must normally be decoded for
  2109 use.
  2110 
  2111 See `setenv' and `getenv'.  */);
  2112   Vprocess_environment = Qnil;
  2113 
  2114   defsubr (&Scall_process);
  2115   defsubr (&Sgetenv_internal);
  2116   defsubr (&Scall_process_region);
  2117 }