code.delx.au - gnu-emacs/blob - nt/cmdproxy.c

   1 /* Proxy shell designed for use with Emacs on Windows 95 and NT.
   2    Copyright (C) 1997 Free Software Foundation, Inc.
   3
   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.
   9
  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.
  14
  15 This file is part of GNU Emacs.
  16
  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)
  20 any later version.
  21
  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.
  26
  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.  */
  31
  32 #include <windows.h>
  33
  34 #include <stdarg.h>  /* va_args */
  35 #include <malloc.h>  /* alloca */
  36 #include <stdlib.h>  /* getenv */
  37 #include <string.h>  /* strlen */
  38
  39
  40 /*******  Mock C library routines  *********************************/
  41
  42 /* These routines are used primarily to minimize the executable size.  */
  43
  44 #define stdin  GetStdHandle (STD_INPUT_HANDLE)
  45 #define stdout GetStdHandle (STD_OUTPUT_HANDLE)
  46 #define stderr GetStdHandle (STD_ERROR_HANDLE)
  47
  48 int
  49 vfprintf(HANDLE hnd, char * msg, va_list args)
  50 {
  51   DWORD bytes_written;
  52   char buf[1024];
  53
  54   wvsprintf (buf, msg, args);
  55   return WriteFile (hnd, buf, strlen (buf), &bytes_written, NULL);
  56 }
  57
  58 int
  59 fprintf(HANDLE hnd, char * msg, ...)
  60 {
  61   va_list args;
  62   int rc;
  63
  64   va_start (args, msg);
  65   rc = vfprintf (hnd, msg, args);
  66   va_end (args);
  67
  68   return rc;
  69 }
  70
  71 int
  72 printf(char * msg, ...)
  73 {
  74   va_list args;
  75   int rc;
  76
  77   va_start (args, msg);
  78   rc = vfprintf (stdout, msg, args);
  79   va_end (args);
  80
  81   return rc;
  82 }
  83
  84 void
  85 fail (char * msg, ...)
  86 {
  87   va_list args;
  88
  89   va_start (args, msg);
  90   vfprintf (stderr, msg, args);
  91   va_end (args);
  92
  93   exit (-1);
  94 }
  95
  96 void
  97 warn (char * msg, ...)
  98 {
  99   va_list args;
 100
 101   va_start (args, msg);
 102   vfprintf (stderr, msg, args);
 103   va_end (args);
 104 }
 105
 106 /******************************************************************/
 107
 108 char *
 109 canon_filename (char *fname)
 110 {
 111   char *p = fname;
 112
 113   while (*p)
 114     {
 115       if (*p == '/')
 116         *p = '\\';
 117       p++;
 118     }
 119
 120   return fname;
 121 }
 122
 123 char *
 124 skip_space (char *str)
 125 {
 126   while (isspace (*str)) str++;
 127   return str;
 128 }
 129
 130 char *
 131 skip_nonspace (char *str)
 132 {
 133   while (*str && !isspace (*str)) str++;
 134   return str;
 135 }
 136
 137 int escape_char = '\\';
 138
 139 /* Get next token from input, advancing pointer.  */
 140 int
 141 get_next_token (char * buf, char ** pSrc)
 142 {
 143   char * p = *pSrc;
 144   char * o = buf;
 145
 146   p = skip_space (p);
 147   if (*p == '"')
 148     {
 149       int escape_char_run = 0;
 150
 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).  */
 155       p++;
 156       while (1)
 157         {
 158           if (p[0] == escape_char && escape_char != '"')
 159             {
 160               escape_char_run++;
 161               continue;
 162             }
 163           else if (p[0] == '"')
 164             {
 165               while (escape_char_run > 1)
 166                 {
 167                   *o++ = escape_char;
 168                   escape_char_run -= 2;
 169                 }
 170
 171               if (escape_char_run > 0)
 172                 {
 173                   /* escaped quote */
 174                   *o++ = *p++;
 175                   escape_char_run = 0;
 176                 }
 177               else if (p[1] == escape_char && escape_char == '"')
 178                 {
 179                   /* quote escaped by doubling */
 180                   *o++ = *p;
 181                   p += 2;
 182                 }
 183               else
 184                 {
 185                   /* The ending quote.  */
 186                   *o = '\0';
 187                   /* Leave input pointer after token.  */
 188                   p++;
 189                   break;
 190                 }
 191             }
 192           else if (p[0] == '\0')
 193             {
 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.  */
 197               *o = '\0';
 198               break;
 199             }
 200           else
 201             {
 202               *o++ = *p++;
 203             }
 204         }
 205     }
 206   else
 207     {
 208       /* Next token is delimited by whitespace.  */
 209       char * p1 = skip_nonspace (p);
 210       memcpy (o, p, p1 - p);
 211       o += (p1 - p);
 212       *o = '\0';
 213       p = p1;
 214     }
 215
 216   *pSrc = p;
 217
 218   return o - buf;
 219 }
 220
 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.  */
 223 int
 224 search_dir (char *dir, char *exec, int bufsize, char *buffer)
 225 {
 226   char *exts[] = {".bat", ".cmd", ".exe", ".com"};
 227   int n_exts = sizeof (exts) / sizeof (char *);
 228   char *dummy;
 229   int i, rc;
 230
 231   /* Search the directory for the program.  */
 232   for (i = 0; i < n_exts; i++)
 233     {
 234       rc = SearchPath (dir, exec, exts[i], bufsize, buffer, &dummy);
 235       if (rc > 0)
 236         return rc;
 237     }
 238
 239   return 0;
 240 }
 241
 242 /* Return the absolute name of executable file PROG, including
 243    any file extensions.  If an absolute name for PROG cannot be found,
 244    return NULL.  */
 245 char *
 246 make_absolute (char *prog)
 247 {
 248   char absname[MAX_PATH];
 249   char dir[MAX_PATH];
 250   char curdir[MAX_PATH];
 251   char *p, *fname;
 252   char *path;
 253   int i;
 254
 255   /* At least partial absolute path specified; search there.  */
 256   if ((isalpha (prog[0]) && prog[1] == ':') ||
 257       (prog[0] == '\\'))
 258     {
 259       /* Split the directory from the filename.  */
 260       fname = strrchr (prog, '\\');
 261       if (!fname)
 262         /* Only a drive specifier is given.  */
 263         fname = prog + 2;
 264       strncpy (dir, prog, fname - prog);
 265       dir[fname - prog] = '\0';
 266
 267       /* Search the directory for the program.  */
 268       if (search_dir (dir, prog, MAX_PATH, absname) > 0)
 269         return strdup (absname);
 270       else
 271         return NULL;
 272     }
 273
 274   if (GetCurrentDirectory (MAX_PATH, curdir) <= 0)
 275     return NULL;
 276
 277   /* Relative path; search in current dir. */
 278   if (strpbrk (prog, "\\"))
 279     {
 280       if (search_dir (curdir, prog, MAX_PATH, absname) > 0)
 281         return strdup (absname);
 282       else
 283         return NULL;
 284     }
 285
 286   /* Just filename; search current directory then PATH.  */
 287   path = alloca (strlen (getenv ("PATH")) + strlen (curdir) + 2);
 288   strcpy (path, curdir);
 289   strcat (path, ";");
 290   strcat (path, getenv ("PATH"));
 291
 292   while (*path)
 293     {
 294       /* Get next directory from path.  */
 295       p = path;
 296       while (*p && *p != ';') p++;
 297       strncpy (dir, path, p - path);
 298       dir[p - path] = '\0';
 299
 300       /* Search the directory for the program.  */
 301       if (search_dir (dir, prog, MAX_PATH, absname) > 0)
 302         return strdup (absname);
 303
 304       /* Move to the next directory.  */
 305       path = p + 1;
 306     }
 307
 308   return NULL;
 309 }
 310
 311 /*****************************************************************/
 312
 313 #if 0
 314 char ** _argv;
 315 int     _argc;
 316
 317 /* Parse commandline into argv array, allowing proper quoting of args.  */
 318 void
 319 setup_argv (void)
 320 {
 321   char * cmdline = GetCommandLine ();
 322   int arg_bytes = 0;
 323
 324
 325 }
 326 #endif
 327
 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.  */
 331
 332 PROCESS_INFORMATION child;
 333 int interactive = TRUE;
 334
 335 BOOL
 336 console_event_handler (DWORD event)
 337 {
 338   switch (event)
 339     {
 340     case CTRL_C_EVENT:
 341     case CTRL_BREAK_EVENT:
 342       if (!interactive)
 343         {
 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);
 354         }
 355       break;
 356
 357 #if 0
 358     default:
 359       /* CLOSE, LOGOFF and SHUTDOWN events - actually we don't get these
 360          under Windows 95.  */
 361       fail ("cmdproxy: received %d event\n", event);
 362       if (child.hProcess)
 363         TerminateProcess (child.hProcess, 0);
 364 #endif
 365     }
 366   return TRUE;
 367 }
 368
 369 /* Change from normal usage; return value indicates whether spawn
 370    succeeded or failed - program return code is returned separately.  */
 371 int
 372 spawn (char * progname, char * cmdline, char * dir, int * retcode)
 373 {
 374   BOOL success = FALSE;
 375   SECURITY_ATTRIBUTES sec_attrs;
 376   STARTUPINFO start;
 377   /* In theory, passing NULL for the environment block to CreateProcess
 378      is the same as passing the value of GetEnvironmentStrings, but
 379      doing this explicitly seems to cure problems running DOS programs
 380      in some cases.  */
 381   char * envblock = GetEnvironmentStrings ();
 382
 383   sec_attrs.nLength = sizeof (sec_attrs);
 384   sec_attrs.lpSecurityDescriptor = NULL;
 385   sec_attrs.bInheritHandle = FALSE;
 386
 387   memset (&start, 0, sizeof (start));
 388   start.cb = sizeof (start);
 389
 390   if (CreateProcess (progname, cmdline, &sec_attrs, NULL, TRUE,
 391                      0, envblock, dir, &start, &child))
 392   {
 393     success = TRUE;
 394     /* wait for completion and pass on return code */
 395     WaitForSingleObject (child.hProcess, INFINITE);
 396     if (retcode)
 397       GetExitCodeProcess (child.hProcess, (DWORD *)retcode);
 398     CloseHandle (child.hThread);
 399     CloseHandle (child.hProcess);
 400     child.hProcess = NULL;
 401   }
 402
 403   FreeEnvironmentStrings (envblock);
 404
 405   return success;
 406 }
 407
 408 /* Return size of current environment block.  */
 409 int
 410 get_env_size ()
 411 {
 412   char * start = GetEnvironmentStrings ();
 413   char * tmp = start;
 414
 415   while (tmp[0] || tmp[1])
 416     ++tmp;
 417   FreeEnvironmentStrings (start);
 418   return  tmp + 2 - start;
 419 }
 420
 421 /*******  Main program  ********************************************/
 422
 423 int
 424 main (int argc, char ** argv)
 425 {
 426   int rc;
 427   int need_shell;
 428   char * cmdline;
 429   char * progname;
 430   int envsize;
 431   char **pass_through_args;
 432   int num_pass_through_args;
 433   char modname[MAX_PATH];
 434   char path[MAX_PATH];
 435   char dir[MAX_PATH];
 436
 437
 438   interactive = TRUE;
 439
 440   SetConsoleCtrlHandler ((PHANDLER_ROUTINE) console_event_handler, TRUE);
 441
 442   if (!GetCurrentDirectory (sizeof (dir), dir))
 443     fail ("error: GetCurrentDirectory failed\n");
 444
 445   /* We serve double duty: we can be called either as a proxy for the
 446      real shell (that is, because we are defined to be the user shell),
 447      or in our role as a helper application for running DOS programs.
 448      In the former case, we interpret the command line options as if we
 449      were a Unix shell, but in the latter case we simply pass our
 450      command line to CreateProcess.  We know which case we are dealing
 451      with by whether argv[0] refers to ourself or to some other program.
 452      (This relies on an arcane feature of CreateProcess, where we can
 453      specify cmdproxy as the module to run, but specify a different
 454      program in the command line - the MSVC startup code sets argv[0]
 455      from the command line.)  */
 456
 457   if (!GetModuleFileName (NULL, modname, sizeof (modname)))
 458     fail ("error: GetModuleFileName failed\n");
 459
 460   /* Change directory to location of .exe so startup directory can be
 461      deleted.  */
 462   progname = strrchr (modname, '\\');
 463   *progname = '\0';
 464   SetCurrentDirectory (modname);
 465   *progname = '\\';
 466
 467   /* Although Emacs always sets argv[0] to an absolute pathname, we
 468      might get run in other ways as well, so convert argv[0] to an
 469      absolute name before comparing to the module name.  */
 470   if (!SearchPath (NULL, argv[0], ".exe", sizeof (path), path, &progname)
 471       || stricmp (modname, path) != 0)
 472     {
 473       /* We are being used as a helper to run a DOS app; just pass
 474          command line to DOS app without change.  */
 475       /* TODO: fill in progname.  */
 476       if (spawn (NULL, GetCommandLine (), dir, &rc))
 477         return rc;
 478       fail ("Could not run %s\n", GetCommandLine ());
 479     }
 480
 481   /* Process command line.  If running interactively (-c or /c not
 482      specified) then spawn a real command shell, passing it the command
 483      line arguments.
 484
 485      If not running interactively, then attempt to execute the specified
 486      command directly.  If necessary, spawn a real shell to execute the
 487      command.
 488
 489   */
 490
 491   progname = NULL;
 492   cmdline = NULL;
 493   /* If no args, spawn real shell for interactive use.  */
 494   need_shell = TRUE;
 495   interactive = TRUE;
 496   /* Ask command.com to create an environment block with a reasonable
 497      amount of free space.  */
 498   envsize = get_env_size () + 300;
 499   pass_through_args = (char **) alloca (argc * sizeof(char *));
 500   num_pass_through_args = 0;
 501
 502   while (--argc > 0)
 503     {
 504       ++argv;
 505       /* Act on switches we recognize (mostly single letter switches,
 506          except for -e); all unrecognised switches and extra args are
 507          passed on to real shell if used (only really of benefit for
 508          interactive use, but allow for batch use as well).  Accept / as
 509          switch char for compatability with cmd.exe.  */
 510       if (((*argv)[0] == '-' || (*argv)[0] == '/') && (*argv)[1] != '\0')
 511         {
 512           if (((*argv)[1] == 'c' || (*argv)[1] == 'C') && ((*argv)[2] == '\0'))
 513             {
 514               if (--argc == 0)
 515                 fail ("error: expecting arg for %s\n", *argv);
 516               cmdline = *(++argv);
 517               interactive = FALSE;
 518             }
 519           else if (((*argv)[1] == 'i' || (*argv)[1] == 'I') && ((*argv)[2] == '\0'))
 520             {
 521               if (cmdline)
 522                 warn ("warning: %s ignored because of -c\n", *argv);
 523             }
 524           else if (((*argv)[1] == 'e' || (*argv[1] == 'E')) && ((*argv)[2] == ':'))
 525             {
 526               int requested_envsize = atoi (*argv + 3);
 527               /* Enforce a reasonable minimum size, as above.  */
 528               if (requested_envsize > envsize)
 529                 envsize = requested_envsize;
 530               /* For sanity, enforce a reasonable maximum.  */
 531               if (envsize > 32768)
 532                 envsize = 32768;
 533             }
 534           else
 535             {
 536               /* warn ("warning: unknown option %s ignored", *argv); */
 537               pass_through_args[num_pass_through_args++] = *argv;
 538             }
 539         }
 540       else
 541         break;
 542     }
 543
 544 #if 0
 545   /* I think this is probably not useful - cmd.exe ignores extra
 546      (non-switch) args in interactive mode, and they cannot be passed on
 547      when -c was given.  */
 548
 549   /* Collect any remaining args after (initial) switches.  */
 550   while (argc-- > 0)
 551     {
 552       pass_through_args[num_pass_through_args++] = *argv++;
 553     }
 554 #else
 555   /* Probably a mistake for there to be extra args; not fatal.  */
 556   if (argc > 0)
 557     warn ("warning: extra args ignored after '%s'\n", argv[-1]);
 558 #endif
 559
 560   pass_through_args[num_pass_through_args] = NULL;
 561
 562   /* If -c option, determine if we must spawn a real shell, or if we can
 563      execute the command directly ourself.  */
 564   if (cmdline)
 565     {
 566       /* If no redirection or piping, and if program can be found, then
 567          run program directly.  Otherwise invoke a real shell. */
 568
 569       static char copout_chars[] = "|<>&";
 570
 571       if (strpbrk (cmdline, copout_chars) == NULL)
 572         {
 573           char *args;
 574
 575           /* The program name is the first token of cmdline.  Since
 576              filenames cannot legally contain embedded quotes, the value
 577              of escape_char doesn't matter.  */
 578           args = cmdline;
 579           if (!get_next_token (path, &args))
 580             fail ("error: no program name specified.\n");
 581
 582           canon_filename (path);
 583           progname = make_absolute (path);
 584
 585           /* If we found the program, run it directly (if not found it
 586              might be an internal shell command, so don't fail).  */
 587           if (progname != NULL)
 588             need_shell = FALSE;
 589         }
 590     }
 591
 592  pass_to_shell:
 593   if (need_shell)
 594     {
 595       char * p;
 596       int    extra_arg_space = 0;
 597       int    run_command_dot_com;
 598
 599       progname = getenv ("COMSPEC");
 600       if (!progname)
 601         fail ("error: COMSPEC is not set\n");
 602
 603       canon_filename (progname);
 604       progname = make_absolute (progname);
 605
 606       if (progname == NULL || strchr (progname, '\\') == NULL)
 607         fail ("error: the program %s could not be found.\n", getenv ("COMSPEC"));
 608
 609       /* Need to set environment size when running command.com.  */
 610       run_command_dot_com =
 611         (stricmp (strrchr (progname, '\\'), "command.com") == 0);
 612
 613       /* Work out how much extra space is required for
 614          pass_through_args.  */
 615       for (argv = pass_through_args; *argv != NULL; ++argv)
 616         /* We don't expect to have to quote switches.  */
 617         extra_arg_space += strlen (*argv) + 2;
 618
 619       if (cmdline)
 620         {
 621           char * buf;
 622
 623           /* Convert to syntax expected by cmd.exe/command.com for
 624              running non-interactively.  Always quote program name in
 625              case path contains spaces (fortunately it can't contain
 626              quotes, since they are illegal in path names).  */
 627
 628           buf = p = alloca (strlen (progname) + extra_arg_space +
 629                             strlen (cmdline) + 16);
 630
 631           /* Quote progname in case it contains spaces.  */
 632           p += wsprintf (p, "\"%s\"", progname);
 633
 634           /* Include pass_through_args verbatim; these are just switches
 635              so should not need quoting.  */
 636           for (argv = pass_through_args; *argv != NULL; ++argv)
 637             p += wsprintf (p, " %s", *argv);
 638
 639           if (run_command_dot_com)
 640             wsprintf(p, " /e:%d /c %s", envsize, cmdline);
 641           else
 642             wsprintf(p, " /c %s", cmdline);
 643           cmdline = buf;
 644         }
 645       else
 646         {
 647           if (run_command_dot_com)
 648             {
 649               /* Provide dir arg expected by command.com when first
 650                  started interactively (the "command search path").  To
 651                  avoid potential problems with spaces in command dir
 652                  (which cannot be quoted - command.com doesn't like it),
 653                  we always use the 8.3 form.  */
 654               GetShortPathName (progname, path, sizeof (path));
 655               p = strrchr (path, '\\');
 656               /* Trailing slash is acceptable, so always leave it.  */
 657               *(++p) = '\0';
 658             }
 659           else
 660             path[0] = '\0';
 661
 662           cmdline = p = alloca (strlen (progname) + extra_arg_space +
 663                                 strlen (path) + 13);
 664
 665           /* Quote progname in case it contains spaces.  */
 666           p += wsprintf (p, "\"%s\" %s", progname, path);
 667
 668           /* Include pass_through_args verbatim; these are just switches
 669              so should not need quoting.  */
 670           for (argv = pass_through_args; *argv != NULL; ++argv)
 671             p += wsprintf (p, " %s", *argv);
 672
 673           if (run_command_dot_com)
 674             wsprintf (p, " /e:%d", envsize);
 675         }
 676     }
 677
 678   if (!progname)
 679     fail ("Internal error: program name not defined\n");
 680
 681   if (!cmdline)
 682     cmdline = progname;
 683
 684   if (spawn (progname, cmdline, dir, &rc))
 685     return rc;
 686
 687   if (!need_shell)
 688     {
 689       need_shell = TRUE;
 690       goto pass_to_shell;
 691     }
 692
 693   fail ("Could not run %s\n", progname);
 694
 695   return 0;
 696 }