1 /* Proxy shell designed for use with Emacs on Windows 95 and NT.
2 Copyright (C) 1997 Free Software Foundation, Inc.
4 Accepts subset of Unix sh(1) command-line options, for compatability
5 with elisp code written for Unix. When possible, executes external
6 programs directly (a common use of /bin/sh by Emacs), otherwise
7 invokes the user-specified command processor to handle built-in shell
8 commands, batch files and interactive mode.
10 The main function is simply to process the "-c string" option in the
11 way /bin/sh does, since the standard Windows command shells use the
12 convention that everything after "/c" (the Windows equivalent of
13 "-c") is the input string.
15 This file is part of GNU Emacs.
17 GNU Emacs is free software; you can redistribute it and/or modify
18 it under the terms of the GNU General Public License as published by
19 the Free Software Foundation; either version 2, or (at your option)
22 GNU Emacs is distributed in the hope that it will be useful,
23 but WITHOUT ANY WARRANTY; without even the implied warranty of
24 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
25 GNU General Public License for more details.
27 You should have received a copy of the GNU General Public License
28 along with GNU Emacs; see the file COPYING. If not, write to
29 the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
30 Boston, MA 02111-1307, USA. */
34 #include <stdarg.h> /* va_args */
35 #include <malloc.h> /* alloca */
36 #include <stdlib.h> /* getenv */
37 #include <string.h> /* strlen */
40 /******* Mock C library routines *********************************/
42 /* These routines are used primarily to minimize the executable size. */
44 #define stdin GetStdHandle (STD_INPUT_HANDLE)
45 #define stdout GetStdHandle (STD_OUTPUT_HANDLE)
46 #define stderr GetStdHandle (STD_ERROR_HANDLE)
49 vfprintf(HANDLE hnd
, char * msg
, va_list args
)
54 wvsprintf (buf
, msg
, args
);
55 return WriteFile (hnd
, buf
, strlen (buf
), &bytes_written
, NULL
);
59 fprintf(HANDLE hnd
, char * msg
, ...)
65 rc
= vfprintf (hnd
, msg
, args
);
72 printf(char * msg
, ...)
78 rc
= vfprintf (stdout
, msg
, args
);
85 fail (char * msg
, ...)
90 vfprintf (stderr
, msg
, args
);
97 warn (char * msg
, ...)
101 va_start (args
, msg
);
102 vfprintf (stderr
, msg
, args
);
106 /******************************************************************/
109 canon_filename (char *fname
)
124 skip_space (char *str
)
126 while (isspace (*str
)) str
++;
131 skip_nonspace (char *str
)
133 while (*str
&& !isspace (*str
)) str
++;
137 int escape_char
= '\\';
139 /* Get next token from input, advancing pointer. */
141 get_next_token (char * buf
, char ** pSrc
)
149 int escape_char_run
= 0;
151 /* Go through src until an ending quote is found, unescaping
152 quotes along the way. If the escape char is not quote, then do
153 special handling of multiple escape chars preceding a quote
154 char (ie. the reverse of what Emacs does to escape quotes). */
158 if (p
[0] == escape_char
&& escape_char
!= '"')
163 else if (p
[0] == '"')
165 while (escape_char_run
> 1)
168 escape_char_run
-= 2;
171 if (escape_char_run
> 0)
177 else if (p
[1] == escape_char
&& escape_char
== '"')
179 /* quote escaped by doubling */
185 /* The ending quote. */
187 /* Leave input pointer after token. */
192 else if (p
[0] == '\0')
194 /* End of string, but no ending quote found. We might want to
195 flag this as an error, but for now will consider the end as
196 the end of the token. */
208 /* Next token is delimited by whitespace. */
209 char * p1
= skip_nonspace (p
);
210 memcpy (o
, p
, p1
- p
);
221 /* Search for EXEC file in DIR. If EXEC does not have an extension,
222 DIR is searched for EXEC with the standard extensions appended. */
224 search_dir (char *dir
, char *exec
, int bufsize
, char *buffer
)
226 char *exts
[] = {".bat", ".cmd", ".exe", ".com"};
227 int n_exts
= sizeof (exts
) / sizeof (char *);
231 /* Search the directory for the program. */
232 for (i
= 0; i
< n_exts
; i
++)
234 rc
= SearchPath (dir
, exec
, exts
[i
], bufsize
, buffer
, &dummy
);
242 /* Return the absolute name of executable file PROG, including
243 any file extensions. If an absolute name for PROG cannot be found,
246 make_absolute (char *prog
)
248 char absname
[MAX_PATH
];
250 char curdir
[MAX_PATH
];
255 /* At least partial absolute path specified; search there. */
256 if ((isalpha (prog
[0]) && prog
[1] == ':') ||
259 /* Split the directory from the filename. */
260 fname
= strrchr (prog
, '\\');
262 /* Only a drive specifier is given. */
264 strncpy (dir
, prog
, fname
- prog
);
265 dir
[fname
- prog
] = '\0';
267 /* Search the directory for the program. */
268 if (search_dir (dir
, prog
, MAX_PATH
, absname
) > 0)
269 return strdup (absname
);
274 if (GetCurrentDirectory (MAX_PATH
, curdir
) <= 0)
277 /* Relative path; search in current dir. */
278 if (strpbrk (prog
, "\\"))
280 if (search_dir (curdir
, prog
, MAX_PATH
, absname
) > 0)
281 return strdup (absname
);
286 /* Just filename; search current directory then PATH. */
287 path
= alloca (strlen (getenv ("PATH")) + strlen (curdir
) + 2);
288 strcpy (path
, curdir
);
290 strcat (path
, getenv ("PATH"));
294 /* Get next directory from path. */
296 while (*p
&& *p
!= ';') p
++;
297 strncpy (dir
, path
, p
- path
);
298 dir
[p
- path
] = '\0';
300 /* Search the directory for the program. */
301 if (search_dir (dir
, prog
, MAX_PATH
, absname
) > 0)
302 return strdup (absname
);
304 /* Move to the next directory. */
311 /*****************************************************************/
317 /* Parse commandline into argv array, allowing proper quoting of args. */
321 char * cmdline
= GetCommandLine ();
328 /* Information about child proc is global, to allow for automatic
329 termination when interrupted. At the moment, only one child process
330 can be running at any one time. */
332 PROCESS_INFORMATION child
;
333 int interactive
= TRUE
;
336 console_event_handler (DWORD event
)
341 case CTRL_BREAK_EVENT
:
344 /* Both command.com and cmd.exe have the annoying behaviour of
345 prompting "Terminate batch job (y/n)?" when interrupted
346 while running a batch file, even if running in
347 non-interactive (-c) mode. Try to make up for this
348 deficiency by forcibly terminating the subprocess if
349 running non-interactively. */
350 if (child
.hProcess
&&
351 WaitForSingleObject (child
.hProcess
, 500) != WAIT_OBJECT_0
)
352 TerminateProcess (child
.hProcess
, 0);
353 exit (STATUS_CONTROL_C_EXIT
);
359 /* CLOSE, LOGOFF and SHUTDOWN events - actually we don't get these
361 fail ("cmdproxy: received %d event\n", event
);
363 TerminateProcess (child
.hProcess
, 0);
370 spawn (char * progname
, char * cmdline
)
373 SECURITY_ATTRIBUTES sec_attrs
;
375 char * envblock
= GetEnvironmentStrings ();
377 sec_attrs
.nLength
= sizeof (sec_attrs
);
378 sec_attrs
.lpSecurityDescriptor
= NULL
;
379 sec_attrs
.bInheritHandle
= FALSE
;
381 memset (&start
, 0, sizeof (start
));
382 start
.cb
= sizeof (start
);
384 if (CreateProcess (progname
, cmdline
, &sec_attrs
, NULL
, TRUE
,
385 0, envblock
, NULL
, &start
, &child
))
387 /* wait for completion and pass on return code */
388 WaitForSingleObject (child
.hProcess
, INFINITE
);
389 GetExitCodeProcess (child
.hProcess
, &rc
);
390 CloseHandle (child
.hThread
);
391 CloseHandle (child
.hProcess
);
392 child
.hProcess
= NULL
;
395 FreeEnvironmentStrings (envblock
);
400 /* Return size of current environment block. */
404 char * start
= GetEnvironmentStrings ();
407 while (tmp
[0] || tmp
[1])
409 FreeEnvironmentStrings (start
);
410 return tmp
+ 2 - start
;
413 /******* Main program ********************************************/
416 main (int argc
, char ** argv
)
423 char **pass_through_args
;
424 int num_pass_through_args
;
425 char modname
[MAX_PATH
];
431 SetConsoleCtrlHandler ((PHANDLER_ROUTINE
) console_event_handler
, TRUE
);
433 /* We serve double duty: we can be called either as a proxy for the
434 real shell (that is, because we are defined to be the user shell),
435 or in our role as a helper application for running DOS programs.
436 In the former case, we interpret the command line options as if we
437 were a Unix shell, but in the latter case we simply pass our
438 command line to CreateProcess. We know which case we are dealing
439 with by whether argv[0] refers to ourself or to some other program.
440 (This relies on an arcane feature of CreateProcess, where we can
441 specify cmdproxy as the module to run, but specify a different
442 program in the command line - the MSVC startup code sets argv[0]
443 from the command line.) */
445 if (!GetModuleFileName (NULL
, modname
, sizeof (modname
)))
446 fail ("error: GetModuleFileName failed\n");
448 /* Although Emacs always sets argv[0] to an absolute pathname, we
449 might get run in other ways as well, so convert argv[0] to an
450 absolute name before comparing to the module name. */
451 if (!SearchPath (NULL
, argv
[0], ".exe", sizeof (path
), path
, &progname
)
452 || stricmp (modname
, path
) != 0)
454 /* We are being used as a helper to run a DOS app; just pass
455 command line to DOS app without change. */
456 /* TODO: fill in progname. */
457 return spawn (NULL
, GetCommandLine ());
460 /* Process command line. If running interactively (-c or /c not
461 specified) then spawn a real command shell, passing it the command
464 If not running interactively, then attempt to execute the specified
465 command directly. If necessary, spawn a real shell to execute the
472 /* If no args, spawn real shell for interactive use. */
475 /* Ask command.com to create an environment block with a reasonable
476 amount of free space. */
477 envsize
= get_env_size () + 300;
478 pass_through_args
= (char **) alloca (argc
* sizeof(char *));
479 num_pass_through_args
= 0;
484 /* Act on switches we recognize (mostly single letter switches,
485 except for -e); all unrecognised switches and extra args are
486 passed on to real shell if used (only really of benefit for
487 interactive use, but allow for batch use as well). Accept / as
488 switch char for compatability with cmd.exe. */
489 if ( ((*argv
)[0] == '-' || (*argv
)[0] == '/') && (*argv
)[1] != '\0' )
491 if ( ((*argv
)[1] == 'c') && ((*argv
)[2] == '\0') )
494 fail ("error: expecting arg for %s\n", *argv
);
498 else if ( ((*argv
)[1] == 'i') && ((*argv
)[2] == '\0') )
501 warn ("warning: %s ignored because of -c\n", *argv
);
503 else if ( ((*argv
)[1] == 'e') && ((*argv
)[2] == ':') )
505 int requested_envsize
= atoi (*argv
+ 3);
506 /* Enforce a reasonable minimum size, as above. */
507 if (requested_envsize
> envsize
)
508 envsize
= requested_envsize
;
509 /* For sanity, enforce a reasonable maximum. */
515 /* warn ("warning: unknown option %s ignored", *argv); */
516 pass_through_args
[num_pass_through_args
++] = *argv
;
524 /* I think this is probably not useful - cmd.exe ignores extra
525 (non-switch) args in interactive mode, and they cannot be passed on
526 when -c was given. */
528 /* Collect any remaining args after (initial) switches. */
531 pass_through_args
[num_pass_through_args
++] = *argv
++;
534 /* Probably a mistake for there to be extra args; not fatal. */
536 warn ("warning: extra args ignored after %s\n", argv
[-1]);
539 pass_through_args
[num_pass_through_args
] = NULL
;
541 /* If -c option, determine if we must spawn a real shell, or if we can
542 execute the command directly ourself. */
545 /* If no redirection or piping, and if program can be found, then
546 run program directly. Otherwise invoke a real shell. */
548 static char copout_chars
[] = "|<>&";
550 if (strpbrk (cmdline
, copout_chars
) == NULL
)
554 /* The program name is the first token of cmdline. Since
555 filenames cannot legally contain embedded quotes, the value
556 of escape_char doesn't matter. */
558 if (!get_next_token (path
, &args
))
559 fail ("error: no program name specified.\n");
561 canon_filename (path
);
562 progname
= make_absolute (path
);
564 /* If we found the program, run it directly (if not found it
565 might be an internal shell command, so don't fail). */
566 if (progname
!= NULL
)
574 int extra_arg_space
= 0;
576 progname
= getenv ("COMSPEC");
578 fail ("error: COMSPEC is not set\n");
580 canon_filename (progname
);
581 progname
= make_absolute (progname
);
583 if (progname
== NULL
|| strchr (progname
, '\\') == NULL
)
584 fail ("error: the program %s could not be found.\n", getenv ("COMSPEC"));
586 /* Work out how much extra space is required for
587 pass_through_args. */
588 for (argv
= pass_through_args
; *argv
!= NULL
; ++argv
)
589 /* We don't expect to have to quote switches. */
590 extra_arg_space
+= strlen (*argv
) + 2;
596 /* Convert to syntax expected by cmd.exe/command.com for
597 running non-interactively. Always quote program name in
598 case path contains spaces (fortunately it can't contain
599 quotes, since they are illegal in path names). */
601 buf
= p
= alloca (strlen (progname
) + extra_arg_space
+
602 strlen (cmdline
) + 16);
604 /* Quote progname in case it contains spaces. */
605 p
+= wsprintf (p
, "\"%s\"", progname
);
607 /* Include pass_through_args verbatim; these are just switches
608 so should not need quoting. */
609 for (argv
= pass_through_args
; *argv
!= NULL
; ++argv
)
610 p
+= wsprintf (p
, " %s", *argv
);
612 /* Always set environment size to something reasonable. */
613 wsprintf(p
, " /e:%d /c %s", envsize
, cmdline
);
618 /* Provide dir arg expected by command.com when first started
619 interactively (the "command search path"). cmd.exe does
620 not require it, but accepts it silently - presumably other
621 DOS compatible shells do the same. To avoid potential
622 problems with spaces in command dir (which cannot be quoted
623 - command.com doesn't like it), we always use the 8.3 form. */
624 GetShortPathName (progname
, path
, sizeof (path
));
625 p
= strrchr (path
, '\\');
626 /* Trailing slash is acceptable, so always leave it. */
629 cmdline
= p
= alloca (strlen (progname
) + extra_arg_space
+
632 /* Quote progname in case it contains spaces. */
633 p
+= wsprintf (p
, "\"%s\" %s", progname
, path
);
635 /* Include pass_through_args verbatim; these are just switches
636 so should not need quoting. */
637 for (argv
= pass_through_args
; *argv
!= NULL
; ++argv
)
638 p
+= wsprintf (p
, " %s", *argv
);
640 /* Always set environment size to something reasonable - again
641 cmd.exe ignores this silently. */
642 wsprintf (p
, " /e:%d", envsize
);
647 fail ("Internal error: program name not defined\n");
652 rc
= spawn (progname
, cmdline
);