lib-src/emacsclient.c

   1 /* Client process that communicates with GNU Emacs acting as server.
   2
   3 Copyright (C) 1986-1987, 1994, 1999-2018 Free Software Foundation, Inc.
   4
   5 This file is part of GNU Emacs.
   6
   7 GNU Emacs is free software: you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation, either version 3 of the License, or (at
  10 your option) any later version.
  11
  12 GNU Emacs is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
  19
  20
  21 #include <config.h>
  22
  23 #ifdef WINDOWSNT
  24
  25 /* ms-w32.h defines these, which disables sockets altogether!  */
  26 # undef _WINSOCKAPI_
  27 # undef _WINSOCK_H
  28
  29 # include <malloc.h>
  30 # include <stdlib.h>
  31 # include <windows.h>
  32 # include <commctrl.h>
  33 # include <io.h>
  34 # include <winsock2.h>
  35
  36 # define NO_SOCKETS_IN_FILE_SYSTEM
  37
  38 # define HSOCKET SOCKET
  39 # define CLOSE_SOCKET closesocket
  40 # define INITIALIZE() (initialize_sockets ())
  41
  42 char *w32_getenv (const char *);
  43 #define egetenv(VAR) w32_getenv(VAR)
  44
  45 #else /* !WINDOWSNT */
  46
  47 # ifdef HAVE_NTGUI
  48 # include <windows.h>
  49 # endif /* HAVE_NTGUI */
  50
  51 # include "syswait.h"
  52
  53 # ifdef HAVE_INET_SOCKETS
  54 #  include <netinet/in.h>
  55 #  ifdef HAVE_SOCKETS
  56 #    include <sys/types.h>
  57 #    include <sys/socket.h>
  58 #    include <sys/un.h>
  59 #  endif /* HAVE_SOCKETS */
  60 # endif
  61 # include <arpa/inet.h>
  62
  63 # define INVALID_SOCKET -1
  64 # define HSOCKET int
  65 # define CLOSE_SOCKET close
  66 # define INITIALIZE()
  67
  68 #define egetenv(VAR) getenv(VAR)
  69
  70 #endif /* !WINDOWSNT */
  71
  72 #undef signal
  73
  74 #include <stdarg.h>
  75 #include <ctype.h>
  76 #include <stdlib.h>
  77 #include <string.h>
  78 #include <getopt.h>
  79 #include <unistd.h>
  80
  81 #include <pwd.h>
  82 #include <sys/stat.h>
  83 #include <signal.h>
  84 #include <errno.h>
  85
  86 #include <unlocked-io.h>
  87
  88 #ifndef VERSION
  89 #define VERSION "unspecified"
  90 #endif
  91 \f
  92
  93 #ifndef EXIT_SUCCESS
  94 #define EXIT_SUCCESS 0
  95 #endif
  96
  97 #ifndef EXIT_FAILURE
  98 #define EXIT_FAILURE 1
  99 #endif
 100
 101 /* Additional space when allocating buffers for filenames, etc.  */
 102 #define EXTRA_SPACE 100
 103
 104 #ifdef min
 105 #undef min
 106 #endif
 107 #define min(x, y) (((x) < (y)) ? (x) : (y))
 108
 109 \f
 110 /* Name used to invoke this program.  */
 111 const char *progname;
 112
 113 /* The first argument to main.  */
 114 int main_argc;
 115
 116 /* The second argument to main.  */
 117 char **main_argv;
 118
 119 /* Nonzero means don't wait for a response from Emacs.  --no-wait.  */
 120 int nowait = 0;
 121
 122 /* Nonzero means don't print messages for successful operations.  --quiet.  */
 123 int quiet = 0;
 124
 125 /* Nonzero means don't print values returned from emacs. --suppress-output.  */
 126 int suppress_output = 0;
 127
 128 /* Nonzero means args are expressions to be evaluated.  --eval.  */
 129 int eval = 0;
 130
 131 /* Nonzero means don't open a new frame.  Inverse of --create-frame.  */
 132 int current_frame = 1;
 133
 134 /* The display on which Emacs should work.  --display.  */
 135 const char *display = NULL;
 136
 137 /* The alternate display we should try if Emacs does not support display.  */
 138 const char *alt_display = NULL;
 139
 140 /* The parent window ID, if we are opening a frame via XEmbed.  */
 141 char *parent_id = NULL;
 142
 143 /* Nonzero means open a new Emacs frame on the current terminal.  */
 144 int tty = 0;
 145
 146 /* If non-NULL, the name of an editor to fallback to if the server
 147    is not running.  --alternate-editor.   */
 148 const char *alternate_editor = NULL;
 149
 150 /* If non-NULL, the filename of the UNIX socket.  */
 151 const char *socket_name = NULL;
 152
 153 /* If non-NULL, the filename of the authentication file.  */
 154 const char *server_file = NULL;
 155
 156 /* If non-NULL, the tramp prefix emacs must use to find the files.  */
 157 const char *tramp_prefix = NULL;
 158
 159 /* PID of the Emacs server process.  */
 160 int emacs_pid = 0;
 161
 162 /* If non-NULL, a string that should form a frame parameter alist to
 163    be used for the new frame.  */
 164 const char *frame_parameters = NULL;
 165
 166 static _Noreturn void print_help_and_exit (void);
 167
 168
 169 struct option longopts[] =
 170 {
 171   { "no-wait",  no_argument,       NULL, 'n' },
 172   { "quiet",    no_argument,       NULL, 'q' },
 173   { "suppress-output", no_argument, NULL, 'u' },
 174   { "eval",     no_argument,       NULL, 'e' },
 175   { "help",     no_argument,       NULL, 'H' },
 176   { "version",  no_argument,       NULL, 'V' },
 177   { "tty",      no_argument,       NULL, 't' },
 178   { "nw",       no_argument,       NULL, 't' },
 179   { "create-frame", no_argument,   NULL, 'c' },
 180   { "alternate-editor", required_argument, NULL, 'a' },
 181   { "frame-parameters", required_argument, NULL, 'F' },
 182 #ifndef NO_SOCKETS_IN_FILE_SYSTEM
 183   { "socket-name",      required_argument, NULL, 's' },
 184 #endif
 185   { "server-file",      required_argument, NULL, 'f' },
 186   { "display",  required_argument, NULL, 'd' },
 187   { "parent-id", required_argument, NULL, 'p' },
 188   { "tramp",    required_argument, NULL, 'T' },
 189   { 0, 0, 0, 0 }
 190 };
 191
 192 \f
 193 /* Like malloc but get fatal error if memory is exhausted.  */
 194
 195 static void *
 196 xmalloc (size_t size)
 197 {
 198   void *result = malloc (size);
 199   if (result == NULL)
 200     {
 201       perror ("malloc");
 202       exit (EXIT_FAILURE);
 203     }
 204   return result;
 205 }
 206
 207 /* Like realloc but get fatal error if memory is exhausted.  */
 208
 209 static void *
 210 xrealloc (void *ptr, size_t size)
 211 {
 212   void *result = realloc (ptr, size);
 213   if (result == NULL)
 214     {
 215       perror ("realloc");
 216       exit (EXIT_FAILURE);
 217     }
 218   return result;
 219 }
 220
 221 /* Like strdup but get a fatal error if memory is exhausted. */
 222 char *xstrdup (const char *);
 223
 224 char *
 225 xstrdup (const char *s)
 226 {
 227   char *result = strdup (s);
 228   if (result == NULL)
 229     {
 230       perror ("strdup");
 231       exit (EXIT_FAILURE);
 232     }
 233   return result;
 234 }
 235
 236 /* From sysdep.c */
 237 #if !defined (HAVE_GET_CURRENT_DIR_NAME) || defined (BROKEN_GET_CURRENT_DIR_NAME)
 238
 239 char *get_current_dir_name (void);
 240
 241 /* Return the current working directory.  Returns NULL on errors.
 242    Any other returned value must be freed with free.  This is used
 243    only when get_current_dir_name is not defined on the system.  */
 244 char *
 245 get_current_dir_name (void)
 246 {
 247   char *buf;
 248   const char *pwd;
 249   struct stat dotstat, pwdstat;
 250   /* If PWD is accurate, use it instead of calling getcwd.  PWD is
 251      sometimes a nicer name, and using it may avoid a fatal error if a
 252      parent directory is searchable but not readable.  */
 253     if ((pwd = egetenv ("PWD")) != 0
 254       && (IS_DIRECTORY_SEP (*pwd) || (*pwd && IS_DEVICE_SEP (pwd[1])))
 255       && stat (pwd, &pwdstat) == 0
 256       && stat (".", &dotstat) == 0
 257       && dotstat.st_ino == pwdstat.st_ino
 258       && dotstat.st_dev == pwdstat.st_dev
 259 #ifdef MAXPATHLEN
 260       && strlen (pwd) < MAXPATHLEN
 261 #endif
 262       )
 263     {
 264       buf = (char *) xmalloc (strlen (pwd) + 1);
 265       strcpy (buf, pwd);
 266     }
 267   else
 268     {
 269       size_t buf_size = 1024;
 270       for (;;)
 271         {
 272           int tmp_errno;
 273           buf = malloc (buf_size);
 274           if (! buf)
 275             break;
 276           if (getcwd (buf, buf_size) == buf)
 277             break;
 278           tmp_errno = errno;
 279           free (buf);
 280           if (tmp_errno != ERANGE)
 281             {
 282               errno = tmp_errno;
 283               return NULL;
 284             }
 285           buf_size *= 2;
 286           if (! buf_size)
 287             {
 288               errno = ENOMEM;
 289               return NULL;
 290             }
 291         }
 292     }
 293   return buf;
 294 }
 295 #endif
 296
 297 #ifdef WINDOWSNT
 298
 299 #define REG_ROOT "SOFTWARE\\GNU\\Emacs"
 300
 301 char *w32_get_resource (HKEY, const char *, LPDWORD);
 302
 303 /* Retrieve an environment variable from the Emacs subkeys of the registry.
 304    Return NULL if the variable was not found, or it was empty.
 305    This code is based on w32_get_resource (w32.c).  */
 306 char *
 307 w32_get_resource (HKEY predefined, const char *key, LPDWORD type)
 308 {
 309   HKEY hrootkey = NULL;
 310   char *result = NULL;
 311   DWORD cbData;
 312
 313   if (RegOpenKeyEx (predefined, REG_ROOT, 0, KEY_READ, &hrootkey) == ERROR_SUCCESS)
 314     {
 315       if (RegQueryValueEx (hrootkey, key, NULL, NULL, NULL, &cbData) == ERROR_SUCCESS)
 316         {
 317           result = (char *) xmalloc (cbData);
 318
 319           if ((RegQueryValueEx (hrootkey, key, NULL, type, (LPBYTE)result, &cbData) != ERROR_SUCCESS)
 320               || (*result == 0))
 321             {
 322               free (result);
 323               result = NULL;
 324             }
 325         }
 326
 327       RegCloseKey (hrootkey);
 328     }
 329
 330   return result;
 331 }
 332
 333 /*
 334   getenv wrapper for Windows
 335
 336   Value is allocated on the heap, and can be free'd.
 337
 338   This is needed to duplicate Emacs's behavior, which is to look for
 339   environment variables in the registry if they don't appear in the
 340   environment.  */
 341 char *
 342 w32_getenv (const char *envvar)
 343 {
 344   char *value;
 345   DWORD dwType;
 346
 347   if ((value = getenv (envvar)))
 348     /* Found in the environment.  strdup it, because values returned
 349        by getenv cannot be free'd.  */
 350     return xstrdup (value);
 351
 352   if (! (value = w32_get_resource (HKEY_CURRENT_USER, envvar, &dwType)) &&
 353       ! (value = w32_get_resource (HKEY_LOCAL_MACHINE, envvar, &dwType)))
 354     {
 355       /* "w32console" is what Emacs on Windows uses for tty-type under -nw.  */
 356       if (strcmp (envvar, "TERM") == 0)
 357         return xstrdup ("w32console");
 358       /* Found neither in the environment nor in the registry.  */
 359       return NULL;
 360     }
 361
 362   if (dwType == REG_SZ)
 363     /* Registry; no need to expand.  */
 364     return value;
 365
 366   if (dwType == REG_EXPAND_SZ)
 367     {
 368       DWORD size;
 369
 370       if ((size = ExpandEnvironmentStrings (value, NULL, 0)))
 371         {
 372           char *buffer = (char *) xmalloc (size);
 373           if (ExpandEnvironmentStrings (value, buffer, size))
 374             {
 375               /* Found and expanded.  */
 376               free (value);
 377               return buffer;
 378             }
 379
 380           /* Error expanding.  */
 381           free (buffer);
 382         }
 383     }
 384
 385   /* Not the right type, or not correctly expanded.  */
 386   free (value);
 387   return NULL;
 388 }
 389
 390 int w32_window_app (void);
 391
 392 int
 393 w32_window_app (void)
 394 {
 395   static int window_app = -1;
 396   char szTitle[MAX_PATH];
 397
 398   if (window_app < 0)
 399     {
 400       /* Checking for STDOUT does not work; it's a valid handle also in
 401          nonconsole apps.  Testing for the console title seems to work. */
 402       window_app = (GetConsoleTitleA (szTitle, MAX_PATH) == 0);
 403       if (window_app)
 404         InitCommonControls ();
 405     }
 406
 407   return window_app;
 408 }
 409
 410 /* execvp wrapper for Windows.  Quotes arguments with embedded spaces.
 411
 412   This is necessary due to the broken implementation of exec* routines in
 413   the Microsoft libraries: they concatenate the arguments together without
 414   quoting special characters, and pass the result to CreateProcess, with
 415   predictably bad results.  By contrast, POSIX execvp passes the arguments
 416   directly into the argv array of the child process.  */
 417
 418 int w32_execvp (const char *, char **);
 419
 420 int
 421 w32_execvp (const char *path, char **argv)
 422 {
 423   int i;
 424
 425   /* Required to allow a .BAT script as alternate editor.  */
 426   argv[0] = (char *) alternate_editor;
 427
 428   for (i = 0; argv[i]; i++)
 429     if (strchr (argv[i], ' '))
 430       {
 431         char *quoted = alloca (strlen (argv[i]) + 3);
 432         sprintf (quoted, "\"%s\"", argv[i]);
 433         argv[i] = quoted;
 434       }
 435
 436   return execvp (path, argv);
 437 }
 438
 439 #undef execvp
 440 #define execvp w32_execvp
 441
 442 /* Emulation of ttyname for Windows.  */
 443 const char *ttyname (int);
 444 const char *
 445 ttyname (int fd)
 446 {
 447   return "CONOUT$";
 448 }
 449
 450 #endif /* WINDOWSNT */
 451
 452 /* Display a normal or error message.
 453    On Windows, use a message box if compiled as a Windows app.  */
 454 static void message (bool, const char *, ...) ATTRIBUTE_FORMAT_PRINTF (2, 3);
 455 static void
 456 message (bool is_error, const char *format, ...)
 457 {
 458   va_list args;
 459
 460   va_start (args, format);
 461
 462 #ifdef WINDOWSNT
 463   if (w32_window_app ())
 464     {
 465       char msg[2048];
 466       vsnprintf (msg, sizeof msg, format, args);
 467       msg[sizeof msg - 1] = '\0';
 468
 469       if (is_error)
 470         MessageBox (NULL, msg, "Emacsclient ERROR", MB_ICONERROR);
 471       else
 472         MessageBox (NULL, msg, "Emacsclient", MB_ICONINFORMATION);
 473     }
 474   else
 475 #endif
 476     {
 477       FILE *f = is_error ? stderr : stdout;
 478
 479       vfprintf (f, format, args);
 480       fflush (f);
 481     }
 482
 483   va_end (args);
 484 }
 485
 486 /* Decode the options from argv and argc.
 487    The global variable `optind' will say how many arguments we used up.  */
 488
 489 static void
 490 decode_options (int argc, char **argv)
 491 {
 492   alternate_editor = egetenv ("ALTERNATE_EDITOR");
 493   tramp_prefix = egetenv ("EMACSCLIENT_TRAMP");
 494
 495   while (1)
 496     {
 497       int opt = getopt_long_only (argc, argv,
 498 #ifndef NO_SOCKETS_IN_FILE_SYSTEM
 499                              "VHnequa:s:f:d:F:tcT:",
 500 #else
 501                              "VHnequa:f:d:F:tcT:",
 502 #endif
 503                              longopts, 0);
 504
 505       if (opt == EOF)
 506         break;
 507
 508       switch (opt)
 509         {
 510         case 0:
 511           /* If getopt returns 0, then it has already processed a
 512              long-named option.  We should do nothing.  */
 513           break;
 514
 515         case 'a':
 516           alternate_editor = optarg;
 517           break;
 518
 519 #ifndef NO_SOCKETS_IN_FILE_SYSTEM
 520         case 's':
 521           socket_name = optarg;
 522           break;
 523 #endif
 524
 525         case 'f':
 526           server_file = optarg;
 527           break;
 528
 529           /* We used to disallow this argument in w32, but it seems better
 530              to allow it, for the occasional case where the user is
 531              connecting with a w32 client to a server compiled with X11
 532              support.  */
 533         case 'd':
 534           display = optarg;
 535           break;
 536
 537         case 'n':
 538           nowait = 1;
 539           break;
 540
 541         case 'e':
 542           eval = 1;
 543           break;
 544
 545         case 'q':
 546           quiet = 1;
 547           break;
 548
 549         case 'u':
 550           suppress_output = 1;
 551           break;
 552
 553         case 'V':
 554           message (false, "emacsclient %s\n", VERSION);
 555           exit (EXIT_SUCCESS);
 556           break;
 557
 558         case 't':
 559           tty = 1;
 560           current_frame = 0;
 561           break;
 562
 563         case 'c':
 564           current_frame = 0;
 565           break;
 566
 567         case 'p':
 568           parent_id = optarg;
 569           current_frame = 0;
 570           break;
 571
 572         case 'H':
 573           print_help_and_exit ();
 574           break;
 575
 576         case 'F':
 577           frame_parameters = optarg;
 578           break;
 579
 580         case 'T':
 581           tramp_prefix = optarg;
 582           break;
 583
 584         default:
 585           message (true, "Try '%s --help' for more information\n", progname);
 586           exit (EXIT_FAILURE);
 587           break;
 588         }
 589     }
 590
 591   /* If the -c option is used (without -t) and no --display argument
 592      is provided, try $DISPLAY.
 593      Without the -c option, we used to set `display' to $DISPLAY by
 594      default, but this changed the default behavior and is sometimes
 595      inconvenient.  So we force users to use "--display $DISPLAY" if
 596      they want Emacs to connect to their current display.
 597
 598      Some window systems have a notion of default display not
 599      reflected in the DISPLAY variable.  If the user didn't give us an
 600      explicit display, try this platform-specific after trying the
 601      display in DISPLAY (if any).  */
 602   if (!current_frame && !tty && !display)
 603     {
 604       /* Set these here so we use a default_display only when the user
 605          didn't give us an explicit display.  */
 606 #if defined (NS_IMPL_COCOA)
 607       alt_display = "ns";
 608 #elif defined (HAVE_NTGUI)
 609       alt_display = "w32";
 610 #endif
 611
 612       display = egetenv ("DISPLAY");
 613     }
 614
 615   if (!display)
 616     {
 617       display = alt_display;
 618       alt_display = NULL;
 619     }
 620
 621   /* A null-string display is invalid.  */
 622   if (display && strlen (display) == 0)
 623     display = NULL;
 624
 625   /* If no display is available, new frames are tty frames.  */
 626   if (!current_frame && !display)
 627     tty = 1;
 628
 629 #ifdef WINDOWSNT
 630   /* Emacs on Windows does not support graphical and text terminal
 631      frames in the same instance.  So, treat the -t and -c options as
 632      equivalent, and open a new frame on the server's terminal.
 633      Ideally, we would only set tty = 1 when the serve is running in a
 634      console, but alas we don't know that.  As a workaround, always
 635      ask for a tty frame, and let server.el figure it out.  */
 636   if (!current_frame)
 637     {
 638       display = NULL;
 639       tty = 1;
 640     }
 641 #endif /* WINDOWSNT */
 642 }
 643
 644 \f
 645 static _Noreturn void
 646 print_help_and_exit (void)
 647 {
 648   /* Spaces and tabs are significant in this message; they're chosen so the
 649      message aligns properly both in a tty and in a Windows message box.
 650      Please try to preserve them; otherwise the output is very hard to read
 651      when using emacsclientw.  */
 652   message (false,
 653            "Usage: %s [OPTIONS] FILE...\n%s%s%s", progname, "\
 654 Tell the Emacs server to visit the specified files.\n\
 655 Every FILE can be either just a FILENAME or [+LINE[:COLUMN]] FILENAME.\n\
 656 \n\
 657 The following OPTIONS are accepted:\n\
 658 -V, --version           Just print version info and return\n\
 659 -H, --help              Print this usage information message\n\
 660 -nw, -t, --tty          Open a new Emacs frame on the current terminal\n\
 661 -c, --create-frame      Create a new frame instead of trying to\n\
 662                         use the current Emacs frame\n\
 663 ", "\
 664 -F ALIST, --frame-parameters=ALIST\n\
 665                         Set the parameters of a new frame\n\
 666 -e, --eval              Evaluate the FILE arguments as ELisp expressions\n\
 667 -n, --no-wait           Don't wait for the server to return\n\
 668 -q, --quiet             Don't display messages on success\n\
 669 -u, --suppress-output   Don't display return values from the server\n\
 670 -d DISPLAY, --display=DISPLAY\n\
 671                         Visit the file in the given display\n\
 672 ", "\
 673 --parent-id=ID          Open in parent window ID, via XEmbed\n"
 674 #ifndef NO_SOCKETS_IN_FILE_SYSTEM
 675 "-s SOCKET, --socket-name=SOCKET\n\
 676                         Set filename of the UNIX socket for communication\n"
 677 #endif
 678 "-f SERVER, --server-file=SERVER\n\
 679                         Set filename of the TCP authentication file\n\
 680 -a EDITOR, --alternate-editor=EDITOR\n\
 681                         Editor to fallback to if the server is not running\n"
 682 "                       If EDITOR is the empty string, start Emacs in daemon\n\
 683                         mode and try connecting again\n"
 684 "-T PREFIX, --tramp=PREFIX\n\
 685                         PREFIX to prepend to filenames sent by emacsclient\n\
 686                         for locating files remotely via Tramp\n"
 687 "\n\
 688 Report bugs with M-x report-emacs-bug.\n");
 689   exit (EXIT_SUCCESS);
 690 }
 691
 692 /* Try to run a different command, or --if no alternate editor is
 693    defined-- exit with an error code.
 694    Uses argv, but gets it from the global variable main_argv.  */
 695
 696 static _Noreturn void
 697 fail (void)
 698 {
 699   if (alternate_editor)
 700     {
 701       size_t extra_args_size = (main_argc - optind + 1) * sizeof (char *);
 702       size_t new_argv_size = extra_args_size;
 703       char **new_argv = xmalloc (new_argv_size);
 704       char *s = xstrdup (alternate_editor);
 705       unsigned toks = 0;
 706
 707       /* Unpack alternate_editor's space-separated tokens into new_argv.  */
 708       for (char *tok = s; tok != NULL && *tok != '\0';)
 709         {
 710           /* Allocate new token.  */
 711           ++toks;
 712           new_argv = xrealloc (new_argv, new_argv_size + toks * sizeof (char *));
 713
 714           /* Skip leading delimiters, and set separator, skipping any
 715              opening quote.  */
 716           size_t skip = strspn (tok, " \"");
 717           tok += skip;
 718           char sep = (skip > 0 && tok[-1] == '"') ? '"' : ' ';
 719
 720           /* Record start of token.  */
 721           new_argv[toks - 1] = tok;
 722
 723           /* Find end of token and overwrite it with NUL.  */
 724           tok = strchr (tok, sep);
 725           if (tok != NULL)
 726             *tok++ = '\0';
 727         }
 728
 729       /* Append main_argv arguments to new_argv.  */
 730       memcpy (&new_argv[toks], main_argv + optind, extra_args_size);
 731
 732       execvp (*new_argv, new_argv);
 733       message (true, "%s: error executing alternate editor \"%s\"\n",
 734                progname, alternate_editor);
 735     }
 736   exit (EXIT_FAILURE);
 737 }
 738
 739 \f
 740 #if !defined (HAVE_SOCKETS) || !defined (HAVE_INET_SOCKETS)
 741
 742 int
 743 main (int argc, char **argv)
 744 {
 745   main_argc = argc;
 746   main_argv = argv;
 747   progname = argv[0];
 748   message (true, "%s: Sorry, the Emacs server is supported only\n"
 749            "on systems with Berkeley sockets.\n",
 750            argv[0]);
 751   fail ();
 752 }
 753
 754 #else /* HAVE_SOCKETS && HAVE_INET_SOCKETS */
 755
 756 #define AUTH_KEY_LENGTH      64
 757 #define SEND_BUFFER_SIZE   4096
 758
 759 /* Buffer to accumulate data to send in TCP connections.  */
 760 char send_buffer[SEND_BUFFER_SIZE + 1];
 761 int sblen = 0;  /* Fill pointer for the send buffer.  */
 762 /* Socket used to communicate with the Emacs server process.  */
 763 HSOCKET emacs_socket = 0;
 764
 765 /* On Windows, the socket library was historically separate from the
 766    standard C library, so errors are handled differently.  */
 767
 768 static void
 769 sock_err_message (const char *function_name)
 770 {
 771 #ifdef WINDOWSNT
 772   char* msg = NULL;
 773
 774   FormatMessage (FORMAT_MESSAGE_FROM_SYSTEM
 775                  | FORMAT_MESSAGE_ALLOCATE_BUFFER
 776                  | FORMAT_MESSAGE_ARGUMENT_ARRAY,
 777                  NULL, WSAGetLastError (), 0, (LPTSTR)&msg, 0, NULL);
 778
 779   message (true, "%s: %s: %s\n", progname, function_name, msg);
 780
 781   LocalFree (msg);
 782 #else
 783   message (true, "%s: %s: %s\n", progname, function_name, strerror (errno));
 784 #endif
 785 }
 786
 787
 788 /* Let's send the data to Emacs when either
 789    - the data ends in "\n", or
 790    - the buffer is full (but this shouldn't happen)
 791    Otherwise, we just accumulate it.  */
 792 static void
 793 send_to_emacs (HSOCKET s, const char *data)
 794 {
 795   size_t dlen;
 796
 797   if (!data)
 798     return;
 799
 800   dlen = strlen (data);
 801   while (*data)
 802     {
 803       size_t part = min (dlen, SEND_BUFFER_SIZE - sblen);
 804       memcpy (&send_buffer[sblen], data, part);
 805       data += part;
 806       sblen += part;
 807
 808       if (sblen == SEND_BUFFER_SIZE
 809           || (sblen > 0 && send_buffer[sblen-1] == '\n'))
 810         {
 811           int sent = send (s, send_buffer, sblen, 0);
 812           if (sent < 0)
 813             {
 814               message (true, "%s: failed to send %d bytes to socket: %s\n",
 815                        progname, sblen, strerror (errno));
 816               fail ();
 817             }
 818           if (sent != sblen)
 819             memmove (send_buffer, &send_buffer[sent], sblen - sent);
 820           sblen -= sent;
 821         }
 822
 823       dlen -= part;
 824     }
 825 }
 826
 827 \f
 828 /* In STR, insert a & before each &, each space, each newline, and
 829    any initial -.  Change spaces to underscores, too, so that the
 830    return value never contains a space.
 831
 832    Does not change the string.  Outputs the result to S.  */
 833 static void
 834 quote_argument (HSOCKET s, const char *str)
 835 {
 836   char *copy = (char *) xmalloc (strlen (str) * 2 + 1);
 837   const char *p;
 838   char *q;
 839
 840   p = str;
 841   q = copy;
 842   while (*p)
 843     {
 844       if (*p == ' ')
 845         {
 846           *q++ = '&';
 847           *q++ = '_';
 848           p++;
 849         }
 850       else if (*p == '\n')
 851         {
 852           *q++ = '&';
 853           *q++ = 'n';
 854           p++;
 855         }
 856       else
 857         {
 858           if (*p == '&' || (*p == '-' && p == str))
 859             *q++ = '&';
 860           *q++ = *p++;
 861         }
 862     }
 863   *q++ = 0;
 864
 865   send_to_emacs (s, copy);
 866
 867   free (copy);
 868 }
 869
 870
 871 /* The inverse of quote_argument.  Removes quoting in string STR by
 872    modifying the string in place.   Returns STR.  */
 873
 874 static char *
 875 unquote_argument (char *str)
 876 {
 877   char *p, *q;
 878
 879   if (! str)
 880     return str;
 881
 882   p = str;
 883   q = str;
 884   while (*p)
 885     {
 886       if (*p == '&')
 887         {
 888           p++;
 889           if (*p == '&')
 890             *p = '&';
 891           else if (*p == '_')
 892             *p = ' ';
 893           else if (*p == 'n')
 894             *p = '\n';
 895           else if (*p == '-')
 896             *p = '-';
 897         }
 898       *q++ = *p++;
 899     }
 900   *q = 0;
 901   return str;
 902 }
 903
 904 \f
 905 static int
 906 file_name_absolute_p (const char *filename)
 907 {
 908   /* Sanity check, it shouldn't happen.  */
 909   if (! filename) return false;
 910
 911   /* /xxx is always an absolute path.  */
 912   if (filename[0] == '/') return true;
 913
 914   /* Empty filenames (which shouldn't happen) are relative.  */
 915   if (filename[0] == '\0') return false;
 916
 917 #ifdef WINDOWSNT
 918   /* X:\xxx is always absolute.  */
 919   if (isalpha ((unsigned char) filename[0])
 920       && filename[1] == ':' && (filename[2] == '\\' || filename[2] == '/'))
 921     return true;
 922
 923   /* Both \xxx and \\xxx\yyy are absolute.  */
 924   if (filename[0] == '\\') return true;
 925 #endif
 926
 927   return false;
 928 }
 929
 930 #ifdef WINDOWSNT
 931 /* Wrapper to make WSACleanup a cdecl, as required by atexit.  */
 932 void __cdecl close_winsock (void);
 933 void __cdecl
 934 close_winsock (void)
 935 {
 936   WSACleanup ();
 937 }
 938
 939 /* Initialize the WinSock2 library.  */
 940 void initialize_sockets (void);
 941 void
 942 initialize_sockets (void)
 943 {
 944   WSADATA wsaData;
 945
 946   if (WSAStartup (MAKEWORD (2, 0), &wsaData))
 947     {
 948       message (true, "%s: error initializing WinSock2\n", progname);
 949       exit (EXIT_FAILURE);
 950     }
 951
 952   atexit (close_winsock);
 953 }
 954 #endif /* WINDOWSNT */
 955
 956 \f
 957 /* Read the information needed to set up a TCP comm channel with
 958    the Emacs server: host, port, and authentication string.  */
 959
 960 static int
 961 get_server_config (const char *config_file, struct sockaddr_in *server,
 962                    char *authentication)
 963 {
 964   char dotted[32];
 965   char *port;
 966   FILE *config = NULL;
 967
 968   if (file_name_absolute_p (config_file))
 969     config = fopen (config_file, "rb");
 970   else
 971     {
 972       const char *home = egetenv ("HOME");
 973
 974       if (home)
 975         {
 976           char *path = xmalloc (strlen (home) + strlen (config_file)
 977                                 + EXTRA_SPACE);
 978           char *z = stpcpy (path, home);
 979           z = stpcpy (z, "/.emacs.d/server/");
 980           strcpy (z, config_file);
 981           config = fopen (path, "rb");
 982           free (path);
 983         }
 984 #ifdef WINDOWSNT
 985       if (!config && (home = egetenv ("APPDATA")))
 986         {
 987           char *path = xmalloc (strlen (home) + strlen (config_file)
 988                                 + EXTRA_SPACE);
 989           char *z = stpcpy (path, home);
 990           z = stpcpy (z, "/.emacs.d/server/");
 991           strcpy (z, config_file);
 992           config = fopen (path, "rb");
 993           free (path);
 994         }
 995 #endif
 996     }
 997
 998   if (! config)
 999     return false;
1000
1001   if (fgets (dotted, sizeof dotted, config)
1002       && (port = strchr (dotted, ':')))
1003     *port++ = '\0';
1004   else
1005     {
1006       message (true, "%s: invalid configuration info\n", progname);
1007       exit (EXIT_FAILURE);
1008     }
1009
1010   server->sin_family = AF_INET;
1011   server->sin_addr.s_addr = inet_addr (dotted);
1012   server->sin_port = htons (atoi (port));
1013
1014   if (! fread (authentication, AUTH_KEY_LENGTH, 1, config))
1015     {
1016       message (true, "%s: cannot read authentication info\n", progname);
1017       exit (EXIT_FAILURE);
1018     }
1019
1020   fclose (config);
1021
1022   return true;
1023 }
1024
1025 static HSOCKET
1026 set_tcp_socket (const char *local_server_file)
1027 {
1028   HSOCKET s;
1029   struct sockaddr_in server;
1030   struct linger l_arg = {1, 1};
1031   char auth_string[AUTH_KEY_LENGTH + 1];
1032
1033   if (! get_server_config (local_server_file, &server, auth_string))
1034     return INVALID_SOCKET;
1035
1036   if (server.sin_addr.s_addr != inet_addr ("127.0.0.1") && !quiet)
1037     message (false, "%s: connected to remote socket at %s\n",
1038              progname, inet_ntoa (server.sin_addr));
1039
1040   /* Open up an AF_INET socket.  */
1041   if ((s = socket (AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0)
1042     {
1043       /* Since we have an alternate to try out, this is not an error
1044          yet; popping out a modal dialog at this stage would make -a
1045          option totally useless for emacsclientw -- the user will
1046          still get an error message if the alternate editor fails.  */
1047 #ifdef WINDOWSNT
1048       if(!(w32_window_app () && alternate_editor))
1049 #endif
1050       sock_err_message ("socket");
1051       return INVALID_SOCKET;
1052     }
1053
1054   /* Set up the socket.  */
1055   if (connect (s, (struct sockaddr *) &server, sizeof server) < 0)
1056     {
1057 #ifdef WINDOWSNT
1058       if(!(w32_window_app () && alternate_editor))
1059 #endif
1060       sock_err_message ("connect");
1061       return INVALID_SOCKET;
1062     }
1063
1064   setsockopt (s, SOL_SOCKET, SO_LINGER, (char *) &l_arg, sizeof l_arg);
1065
1066   /* Send the authentication.  */
1067   auth_string[AUTH_KEY_LENGTH] = '\0';
1068
1069   send_to_emacs (s, "-auth ");
1070   send_to_emacs (s, auth_string);
1071   send_to_emacs (s, " ");
1072
1073   return s;
1074 }
1075
1076
1077 /* Returns 1 if PREFIX is a prefix of STRING. */
1078 static int
1079 strprefix (const char *prefix, const char *string)
1080 {
1081   return !strncmp (prefix, string, strlen (prefix));
1082 }
1083
1084 /* Get tty name and type.  If successful, return the type in TTY_TYPE
1085    and the name in TTY_NAME, and return 1.  Otherwise, fail if NOABORT
1086    is zero, or return 0 if NOABORT is non-zero.  */
1087
1088 static int
1089 find_tty (const char **tty_type, const char **tty_name, int noabort)
1090 {
1091   const char *type = egetenv ("TERM");
1092   const char *name = ttyname (fileno (stdout));
1093
1094   if (!name)
1095     {
1096       if (noabort)
1097         return 0;
1098       else
1099         {
1100           message (true, "%s: could not get terminal name\n", progname);
1101           fail ();
1102         }
1103     }
1104
1105   if (!type)
1106     {
1107       if (noabort)
1108         return 0;
1109       else
1110         {
1111           message (true, "%s: please set the TERM variable to your terminal type\n",
1112                    progname);
1113           fail ();
1114         }
1115     }
1116
1117   if (strcmp (type, "eterm") == 0)
1118     {
1119       if (noabort)
1120         return 0;
1121       else
1122         {
1123           /* This causes nasty, MULTI_KBOARD-related input lockouts. */
1124           message (true, "%s: opening a frame in an Emacs term buffer"
1125                    " is not supported\n", progname);
1126           fail ();
1127         }
1128     }
1129
1130   *tty_name = name;
1131   *tty_type = type;
1132   return 1;
1133 }
1134
1135
1136 #if !defined (NO_SOCKETS_IN_FILE_SYSTEM)
1137
1138 /* Three possibilities:
1139    2 - can't be `stat'ed                (sets errno)
1140    1 - isn't owned by us
1141    0 - success: none of the above */
1142
1143 static int
1144 socket_status (const char *name)
1145 {
1146   struct stat statbfr;
1147
1148   if (stat (name, &statbfr) == -1)
1149     return 2;
1150
1151   if (statbfr.st_uid != geteuid ())
1152     return 1;
1153
1154   return 0;
1155 }
1156
1157 \f
1158 /* A signal handler that passes the signal to the Emacs process.
1159    Useful for SIGWINCH.  */
1160
1161 static void
1162 pass_signal_to_emacs (int signalnum)
1163 {
1164   int old_errno = errno;
1165
1166   if (emacs_pid)
1167     kill (emacs_pid, signalnum);
1168
1169   signal (signalnum, pass_signal_to_emacs);
1170   errno = old_errno;
1171 }
1172
1173 /* Signal handler for SIGCONT; notify the Emacs process that it can
1174    now resume our tty frame.  */
1175
1176 static void
1177 handle_sigcont (int signalnum)
1178 {
1179   int old_errno = errno;
1180   pid_t pgrp = getpgrp ();
1181   pid_t tcpgrp = tcgetpgrp (1);
1182
1183   if (tcpgrp == pgrp)
1184     {
1185       /* We are in the foreground.  */
1186       send_to_emacs (emacs_socket, "-resume \n");
1187     }
1188   else if (0 <= tcpgrp && tty)
1189     {
1190       /* We are in the background; cancel the continue.  */
1191       kill (-pgrp, SIGTTIN);
1192     }
1193
1194   signal (signalnum, handle_sigcont);
1195   errno = old_errno;
1196 }
1197
1198 /* Signal handler for SIGTSTP; notify the Emacs process that we are
1199    going to sleep.  Normally the suspend is initiated by Emacs via
1200    server-handle-suspend-tty, but if the server gets out of sync with
1201    reality, we may get a SIGTSTP on C-z.  Handling this signal and
1202    notifying Emacs about it should get things under control again.  */
1203
1204 static void
1205 handle_sigtstp (int signalnum)
1206 {
1207   int old_errno = errno;
1208   sigset_t set;
1209
1210   if (emacs_socket)
1211     send_to_emacs (emacs_socket, "-suspend \n");
1212
1213   /* Unblock this signal and call the default handler by temporarily
1214      changing the handler and resignaling.  */
1215   sigprocmask (SIG_BLOCK, NULL, &set);
1216   sigdelset (&set, signalnum);
1217   signal (signalnum, SIG_DFL);
1218   raise (signalnum);
1219   sigprocmask (SIG_SETMASK, &set, NULL); /* Let's the above signal through. */
1220   signal (signalnum, handle_sigtstp);
1221
1222   errno = old_errno;
1223 }
1224
1225
1226 /* Set up signal handlers before opening a frame on the current tty.  */
1227
1228 static void
1229 init_signals (void)
1230 {
1231   /* Set up signal handlers. */
1232   signal (SIGWINCH, pass_signal_to_emacs);
1233
1234   /* Don't pass SIGINT and SIGQUIT to Emacs, because it has no way of
1235      deciding which terminal the signal came from.  C-g is now a
1236      normal input event on secondary terminals.  */
1237 #if 0
1238   signal (SIGINT, pass_signal_to_emacs);
1239   signal (SIGQUIT, pass_signal_to_emacs);
1240 #endif
1241
1242   signal (SIGCONT, handle_sigcont);
1243   signal (SIGTSTP, handle_sigtstp);
1244   signal (SIGTTOU, handle_sigtstp);
1245 }
1246
1247
1248 static HSOCKET
1249 set_local_socket (const char *local_socket_name)
1250 {
1251   HSOCKET s;
1252   struct sockaddr_un server;
1253
1254   /* Open up an AF_UNIX socket in this person's home directory.  */
1255   if ((s = socket (AF_UNIX, SOCK_STREAM, 0)) < 0)
1256     {
1257       message (true, "%s: socket: %s\n", progname, strerror (errno));
1258       return INVALID_SOCKET;
1259     }
1260
1261   server.sun_family = AF_UNIX;
1262
1263   {
1264     int sock_status;
1265     int saved_errno;
1266     const char *server_name = local_socket_name;
1267     const char *tmpdir = NULL;
1268     char *tmpdir_storage = NULL;
1269     char *socket_name_storage = NULL;
1270
1271     if (!strchr (local_socket_name, '/') && !strchr (local_socket_name, '\\'))
1272       {
1273         /* socket_name is a file name component.  */
1274         long uid = geteuid ();
1275         tmpdir = egetenv ("TMPDIR");
1276         if (!tmpdir)
1277           {
1278 #ifdef DARWIN_OS
1279 #ifndef _CS_DARWIN_USER_TEMP_DIR
1280 #define _CS_DARWIN_USER_TEMP_DIR 65537
1281 #endif
1282             size_t n = confstr (_CS_DARWIN_USER_TEMP_DIR, NULL, (size_t) 0);
1283             if (n > 0)
1284               {
1285                 tmpdir = tmpdir_storage = xmalloc (n);
1286                 confstr (_CS_DARWIN_USER_TEMP_DIR, tmpdir_storage, n);
1287               }
1288             else
1289 #endif
1290               tmpdir = "/tmp";
1291           }
1292         socket_name_storage =
1293           xmalloc (strlen (tmpdir) + strlen (server_name) + EXTRA_SPACE);
1294         char *z = stpcpy (socket_name_storage, tmpdir);
1295         z += sprintf (z, "/emacs%ld/", uid);
1296         strcpy (z, server_name);
1297         local_socket_name = socket_name_storage;
1298       }
1299
1300     if (strlen (local_socket_name) < sizeof (server.sun_path))
1301       strcpy (server.sun_path, local_socket_name);
1302     else
1303       {
1304         message (true, "%s: socket-name %s too long\n",
1305                  progname, local_socket_name);
1306         fail ();
1307       }
1308
1309     /* See if the socket exists, and if it's owned by us. */
1310     sock_status = socket_status (server.sun_path);
1311     saved_errno = errno;
1312     if (sock_status && tmpdir)
1313       {
1314         /* Failing that, see if LOGNAME or USER exist and differ from
1315            our euid.  If so, look for a socket based on the UID
1316            associated with the name.  This is reminiscent of the logic
1317            that init_editfns uses to set the global Vuser_full_name.  */
1318
1319         const char *user_name = egetenv ("LOGNAME");
1320
1321         if (!user_name)
1322           user_name = egetenv ("USER");
1323
1324         if (user_name)
1325           {
1326             struct passwd *pw = getpwnam (user_name);
1327
1328             if (pw && (pw->pw_uid != geteuid ()))
1329               {
1330                 /* We're running under su, apparently. */
1331                 long uid = pw->pw_uid;
1332                 char *user_socket_name
1333                   = xmalloc (strlen (tmpdir) + strlen (server_name)
1334                              + EXTRA_SPACE);
1335                 char *z = stpcpy (user_socket_name, tmpdir);
1336                 z += sprintf (z, "/emacs%ld/", uid);
1337                 strcpy (z, server_name);
1338
1339                 if (strlen (user_socket_name) < sizeof (server.sun_path))
1340                   strcpy (server.sun_path, user_socket_name);
1341                 else
1342                   {
1343                     message (true, "%s: socket-name %s too long\n",
1344                              progname, user_socket_name);
1345                     exit (EXIT_FAILURE);
1346                   }
1347                 free (user_socket_name);
1348
1349                 sock_status = socket_status (server.sun_path);
1350                 saved_errno = errno;
1351               }
1352             else
1353               errno = saved_errno;
1354           }
1355       }
1356
1357     free (socket_name_storage);
1358     free (tmpdir_storage);
1359
1360     switch (sock_status)
1361       {
1362       case 1:
1363         /* There's a socket, but it isn't owned by us.  This is OK if
1364            we are root. */
1365         if (0 != geteuid ())
1366           {
1367             message (true, "%s: Invalid socket owner\n", progname);
1368             return INVALID_SOCKET;
1369           }
1370         break;
1371
1372       case 2:
1373         /* `stat' failed */
1374         if (saved_errno == ENOENT)
1375           message (true,
1376                    "%s: can't find socket; have you started the server?\n\
1377 To start the server in Emacs, type \"M-x server-start\".\n",
1378                    progname);
1379         else
1380           message (true, "%s: can't stat %s: %s\n",
1381                    progname, server.sun_path, strerror (saved_errno));
1382         return INVALID_SOCKET;
1383       }
1384   }
1385
1386   if (connect (s, (struct sockaddr *) &server, strlen (server.sun_path) + 2)
1387       < 0)
1388     {
1389       message (true, "%s: connect: %s\n", progname, strerror (errno));
1390       return INVALID_SOCKET;
1391     }
1392
1393   return s;
1394 }
1395 #endif /* ! NO_SOCKETS_IN_FILE_SYSTEM */
1396
1397 static HSOCKET
1398 set_socket (int no_exit_if_error)
1399 {
1400   HSOCKET s;
1401   const char *local_server_file = server_file;
1402
1403   INITIALIZE ();
1404
1405 #ifndef NO_SOCKETS_IN_FILE_SYSTEM
1406   /* Explicit --socket-name argument.  */
1407   if (socket_name)
1408     {
1409       s = set_local_socket (socket_name);
1410       if ((s != INVALID_SOCKET) || no_exit_if_error)
1411         return s;
1412       message (true, "%s: error accessing socket \"%s\"\n",
1413                progname, socket_name);
1414       exit (EXIT_FAILURE);
1415     }
1416 #endif
1417
1418   /* Explicit --server-file arg or EMACS_SERVER_FILE variable.  */
1419   if (!local_server_file)
1420     local_server_file = egetenv ("EMACS_SERVER_FILE");
1421
1422   if (local_server_file)
1423     {
1424       s = set_tcp_socket (local_server_file);
1425       if ((s != INVALID_SOCKET) || no_exit_if_error)
1426         return s;
1427
1428       message (true, "%s: error accessing server file \"%s\"\n",
1429                progname, local_server_file);
1430       exit (EXIT_FAILURE);
1431     }
1432
1433 #ifndef NO_SOCKETS_IN_FILE_SYSTEM
1434   /* Implicit local socket.  */
1435   s = set_local_socket ("server");
1436   if (s != INVALID_SOCKET)
1437     return s;
1438 #endif
1439
1440   /* Implicit server file.  */
1441   s = set_tcp_socket ("server");
1442   if ((s != INVALID_SOCKET) || no_exit_if_error)
1443     return s;
1444
1445   /* No implicit or explicit socket, and no alternate editor.  */
1446   message (true, "%s: No socket or alternate editor.  Please use:\n\n"
1447 #ifndef NO_SOCKETS_IN_FILE_SYSTEM
1448 "\t--socket-name\n"
1449 #endif
1450 "\t--server-file      (or environment variable EMACS_SERVER_FILE)\n\
1451 \t--alternate-editor (or environment variable ALTERNATE_EDITOR)\n",
1452            progname);
1453   exit (EXIT_FAILURE);
1454 }
1455
1456 #ifdef HAVE_NTGUI
1457 FARPROC set_fg;  /* Pointer to AllowSetForegroundWindow.  */
1458 FARPROC get_wc;  /* Pointer to RealGetWindowClassA.  */
1459
1460 void w32_set_user_model_id (void);
1461
1462 void
1463 w32_set_user_model_id (void)
1464 {
1465   HMODULE shell;
1466   HRESULT (WINAPI * set_user_model) (const wchar_t * id);
1467
1468   /* On Windows 7 and later, we need to set the user model ID
1469      to associate emacsclient launched files with Emacs frames
1470      in the UI.  */
1471   shell = LoadLibrary ("shell32.dll");
1472   if (shell)
1473     {
1474       set_user_model
1475         = (void *) GetProcAddress (shell,
1476                                    "SetCurrentProcessExplicitAppUserModelID");
1477       /* If the function is defined, then we are running on Windows 7
1478          or newer, and the UI uses this to group related windows
1479          together.  Since emacs, runemacs, emacsclient are related, we
1480          want them grouped even though the executables are different,
1481          so we need to set a consistent ID between them.  */
1482       if (set_user_model)
1483         set_user_model (L"GNU.Emacs");
1484
1485       FreeLibrary (shell);
1486     }
1487 }
1488
1489 BOOL CALLBACK w32_find_emacs_process (HWND, LPARAM);
1490
1491 BOOL CALLBACK
1492 w32_find_emacs_process (HWND hWnd, LPARAM lParam)
1493 {
1494   DWORD pid;
1495   char class[6];
1496
1497   /* Reject any window not of class "Emacs".  */
1498   if (! get_wc (hWnd, class, sizeof (class))
1499       || strcmp (class, "Emacs"))
1500     return TRUE;
1501
1502   /* We only need the process id, not the thread id.  */
1503   (void) GetWindowThreadProcessId (hWnd, &pid);
1504
1505   /* Not the one we're looking for.  */
1506   if (pid != (DWORD) emacs_pid) return TRUE;
1507
1508   /* OK, let's raise it.  */
1509   set_fg (emacs_pid);
1510
1511   /* Stop enumeration.  */
1512   return FALSE;
1513 }
1514
1515 /* Search for a window of class "Emacs" and owned by a process with
1516    process id = emacs_pid.  If found, allow it to grab the focus.  */
1517 void w32_give_focus (void);
1518
1519 void
1520 w32_give_focus (void)
1521 {
1522   HANDLE user32;
1523
1524   /* It shouldn't happen when dealing with TCP sockets.  */
1525   if (!emacs_pid) return;
1526
1527   user32 = GetModuleHandle ("user32.dll");
1528
1529   if (!user32)
1530     return;
1531
1532   /* Modern Windows restrict which processes can set the foreground window.
1533      emacsclient can allow Emacs to grab the focus by calling the function
1534      AllowSetForegroundWindow.  Unfortunately, older Windows (W95, W98 and
1535      NT) lack this function, so we have to check its availability.  */
1536   if ((set_fg = GetProcAddress (user32, "AllowSetForegroundWindow"))
1537       && (get_wc = GetProcAddress (user32, "RealGetWindowClassA")))
1538     EnumWindows (w32_find_emacs_process, (LPARAM) 0);
1539 }
1540 #endif /* HAVE_NTGUI */
1541
1542 /* Start the emacs daemon and try to connect to it.  */
1543
1544 static void
1545 start_daemon_and_retry_set_socket (void)
1546 {
1547 #ifndef WINDOWSNT
1548   pid_t dpid;
1549   int status;
1550
1551   dpid = fork ();
1552
1553   if (dpid > 0)
1554     {
1555       pid_t w;
1556       w = waitpid (dpid, &status, WUNTRACED | WCONTINUED);
1557
1558       if ((w == -1) || !WIFEXITED (status) || WEXITSTATUS (status))
1559         {
1560           message (true, "Error: Could not start the Emacs daemon\n");
1561           exit (EXIT_FAILURE);
1562         }
1563
1564       /* Try connecting, the daemon should have started by now.  */
1565       message (true, "Emacs daemon should have started, trying to connect again\n");
1566       if ((emacs_socket = set_socket (1)) == INVALID_SOCKET)
1567         {
1568           message (true, "Error: Cannot connect even after starting the Emacs daemon\n");
1569           exit (EXIT_FAILURE);
1570         }
1571     }
1572   else if (dpid < 0)
1573     {
1574       fprintf (stderr, "Error: Cannot fork!\n");
1575       exit (EXIT_FAILURE);
1576     }
1577   else
1578     {
1579       char emacs[] = "emacs";
1580       char daemon_option[] = "--daemon";
1581       char *d_argv[3];
1582       d_argv[0] = emacs;
1583       d_argv[1] = daemon_option;
1584       d_argv[2] = 0;
1585       if (socket_name != NULL)
1586         {
1587           /* Pass  --daemon=socket_name as argument.  */
1588           const char *deq = "--daemon=";
1589           char *daemon_arg = xmalloc (strlen (deq)
1590                                       + strlen (socket_name) + 1);
1591           strcpy (stpcpy (daemon_arg, deq), socket_name);
1592           d_argv[1] = daemon_arg;
1593         }
1594       execvp ("emacs", d_argv);
1595       message (true, "%s: error starting emacs daemon\n", progname);
1596     }
1597 #else  /* WINDOWSNT */
1598   DWORD wait_result;
1599   HANDLE w32_daemon_event;
1600   STARTUPINFO si;
1601   PROCESS_INFORMATION pi;
1602
1603   ZeroMemory (&si, sizeof si);
1604   si.cb = sizeof si;
1605   ZeroMemory (&pi, sizeof pi);
1606
1607   /* We start Emacs in daemon mode, and then wait for it to signal us
1608      it is ready to accept client connections, by asserting an event
1609      whose name is known to the daemon (defined by nt/inc/ms-w32.h).  */
1610
1611   if (!CreateProcess (NULL, (LPSTR)"emacs --daemon", NULL, NULL, FALSE,
1612                       CREATE_NO_WINDOW, NULL, NULL, &si, &pi))
1613     {
1614       char* msg = NULL;
1615
1616       FormatMessage (FORMAT_MESSAGE_FROM_SYSTEM
1617                      | FORMAT_MESSAGE_ALLOCATE_BUFFER
1618                      | FORMAT_MESSAGE_ARGUMENT_ARRAY,
1619                      NULL, GetLastError (), 0, (LPTSTR)&msg, 0, NULL);
1620       message (true, "%s: error starting emacs daemon (%s)\n", progname, msg);
1621       exit (EXIT_FAILURE);
1622     }
1623
1624   w32_daemon_event = CreateEvent (NULL, TRUE, FALSE, W32_DAEMON_EVENT);
1625   if (w32_daemon_event == NULL)
1626     {
1627       message (true, "Couldn't create Windows daemon event");
1628       exit (EXIT_FAILURE);
1629     }
1630   if ((wait_result = WaitForSingleObject (w32_daemon_event, INFINITE))
1631       != WAIT_OBJECT_0)
1632     {
1633       const char *msg = NULL;
1634
1635       switch (wait_result)
1636         {
1637         case WAIT_ABANDONED:
1638           msg = "The daemon exited unexpectedly";
1639           break;
1640         case WAIT_TIMEOUT:
1641           /* Can't happen due to INFINITE.  */
1642         default:
1643         case WAIT_FAILED:
1644           FormatMessage (FORMAT_MESSAGE_FROM_SYSTEM
1645                          | FORMAT_MESSAGE_ALLOCATE_BUFFER
1646                          | FORMAT_MESSAGE_ARGUMENT_ARRAY,
1647                          NULL, GetLastError (), 0, (LPTSTR)&msg, 0, NULL);
1648           break;
1649         }
1650       message (true, "Error: Could not start the Emacs daemon: %s\n", msg);
1651       exit (EXIT_FAILURE);
1652     }
1653   CloseHandle (w32_daemon_event);
1654
1655   /* Try connecting, the daemon should have started by now.  */
1656   /* It's just a progress message, so don't pop a dialog if this is
1657      emacsclientw.  */
1658   if (!w32_window_app ())
1659     message (true,
1660              "Emacs daemon should have started, trying to connect again\n");
1661   if ((emacs_socket = set_socket (1)) == INVALID_SOCKET)
1662     {
1663       message (true,
1664                "Error: Cannot connect even after starting the Emacs daemon\n");
1665       exit (EXIT_FAILURE);
1666     }
1667 #endif  /* WINDOWSNT */
1668 }
1669
1670 int
1671 main (int argc, char **argv)
1672 {
1673   int rl = 0, needlf = 0;
1674   char *cwd, *str;
1675   char string[BUFSIZ+1];
1676   int start_daemon_if_needed;
1677   int exit_status = EXIT_SUCCESS;
1678
1679   main_argc = argc;
1680   main_argv = argv;
1681   progname = argv[0];
1682
1683 #ifdef HAVE_NTGUI
1684   /* On Windows 7 and later, we need to explicitly associate
1685      emacsclient with emacs so the UI behaves sensibly.  This
1686      association does no harm if we're not actually connecting to an
1687      Emacs using a window display.  */
1688   w32_set_user_model_id ();
1689 #endif /* HAVE_NTGUI */
1690
1691   /* Process options.  */
1692   decode_options (argc, argv);
1693
1694   if ((argc - optind < 1) && !eval && current_frame)
1695     {
1696       message (true, "%s: file name or argument required\n"
1697                "Try '%s --help' for more information\n",
1698                progname, progname);
1699       exit (EXIT_FAILURE);
1700     }
1701
1702 #ifndef WINDOWSNT
1703   if (tty)
1704     {
1705       pid_t pgrp = getpgrp ();
1706       pid_t tcpgrp = tcgetpgrp (1);
1707       if (0 <= tcpgrp && tcpgrp != pgrp)
1708         kill (-pgrp, SIGTTIN);
1709     }
1710 #endif /* !WINDOWSNT */
1711
1712   /* If alternate_editor is the empty string, start the emacs daemon
1713      in case of failure to connect.  */
1714   start_daemon_if_needed = (alternate_editor
1715                             && (alternate_editor[0] == '\0'));
1716
1717   emacs_socket = set_socket (alternate_editor || start_daemon_if_needed);
1718   if (emacs_socket == INVALID_SOCKET)
1719     {
1720       if (! start_daemon_if_needed)
1721         fail ();
1722
1723       start_daemon_and_retry_set_socket ();
1724     }
1725
1726   cwd = get_current_dir_name ();
1727   if (cwd == 0)
1728     {
1729       message (true, "%s: %s\n", progname,
1730                "Cannot get current working directory");
1731       fail ();
1732     }
1733
1734 #ifdef HAVE_NTGUI
1735   if (display && !strcmp (display, "w32"))
1736   w32_give_focus ();
1737 #endif /* HAVE_NTGUI */
1738
1739   /* Send over our environment and current directory. */
1740   if (!current_frame)
1741     {
1742       int i;
1743       for (i = 0; environ[i]; i++)
1744         {
1745           send_to_emacs (emacs_socket, "-env ");
1746           quote_argument (emacs_socket, environ[i]);
1747           send_to_emacs (emacs_socket, " ");
1748         }
1749     }
1750   send_to_emacs (emacs_socket, "-dir ");
1751   if (tramp_prefix)
1752     quote_argument (emacs_socket, tramp_prefix);
1753   quote_argument (emacs_socket, cwd);
1754   free (cwd);
1755   send_to_emacs (emacs_socket, "/");
1756   send_to_emacs (emacs_socket, " ");
1757
1758  retry:
1759   if (nowait)
1760     send_to_emacs (emacs_socket, "-nowait ");
1761
1762   if (current_frame)
1763     send_to_emacs (emacs_socket, "-current-frame ");
1764
1765   if (display)
1766     {
1767       send_to_emacs (emacs_socket, "-display ");
1768       quote_argument (emacs_socket, display);
1769       send_to_emacs (emacs_socket, " ");
1770     }
1771
1772   if (parent_id)
1773     {
1774       send_to_emacs (emacs_socket, "-parent-id ");
1775       quote_argument (emacs_socket, parent_id);
1776       send_to_emacs (emacs_socket, " ");
1777     }
1778
1779   if (frame_parameters && !current_frame)
1780     {
1781       send_to_emacs (emacs_socket, "-frame-parameters ");
1782       quote_argument (emacs_socket, frame_parameters);
1783       send_to_emacs (emacs_socket, " ");
1784     }
1785
1786   /* Unless we are certain we don't want to occupy the tty, send our
1787      tty information to Emacs.  For example, in daemon mode Emacs may
1788      need to occupy this tty if no other frame is available.  */
1789   if (!current_frame || !eval)
1790     {
1791       const char *tty_type, *tty_name;
1792
1793       if (find_tty (&tty_type, &tty_name, !tty))
1794         {
1795 #if !defined (NO_SOCKETS_IN_FILE_SYSTEM)
1796           init_signals ();
1797 #endif
1798           send_to_emacs (emacs_socket, "-tty ");
1799           quote_argument (emacs_socket, tty_name);
1800           send_to_emacs (emacs_socket, " ");
1801           quote_argument (emacs_socket, tty_type);
1802           send_to_emacs (emacs_socket, " ");
1803         }
1804     }
1805
1806   if (!current_frame && !tty)
1807     send_to_emacs (emacs_socket, "-window-system ");
1808
1809   if ((argc - optind > 0))
1810     {
1811       int i;
1812       for (i = optind; i < argc; i++)
1813         {
1814
1815           if (eval)
1816             {
1817               /* Don't prepend cwd or anything like that.  */
1818               send_to_emacs (emacs_socket, "-eval ");
1819               quote_argument (emacs_socket, argv[i]);
1820               send_to_emacs (emacs_socket, " ");
1821               continue;
1822             }
1823
1824           if (*argv[i] == '+')
1825             {
1826               char *p = argv[i] + 1;
1827               while (isdigit ((unsigned char) *p) || *p == ':') p++;
1828               if (*p == 0)
1829                 {
1830                   send_to_emacs (emacs_socket, "-position ");
1831                   quote_argument (emacs_socket, argv[i]);
1832                   send_to_emacs (emacs_socket, " ");
1833                   continue;
1834                 }
1835             }
1836 #ifdef WINDOWSNT
1837           else if (! file_name_absolute_p (argv[i])
1838                    && (isalpha (argv[i][0]) && argv[i][1] == ':'))
1839             /* Windows can have a different default directory for each
1840                drive, so the cwd passed via "-dir" is not sufficient
1841                to account for that.
1842                If the user uses <drive>:<relpath>, we hence need to be
1843                careful to expand <relpath> with the default directory
1844                corresponding to <drive>.  */
1845             {
1846               char *filename = (char *) xmalloc (MAX_PATH);
1847               DWORD size;
1848
1849               size = GetFullPathName (argv[i], MAX_PATH, filename, NULL);
1850               if (size > 0 && size < MAX_PATH)
1851                 argv[i] = filename;
1852               else
1853                 free (filename);
1854             }
1855 #endif
1856
1857           send_to_emacs (emacs_socket, "-file ");
1858           if (tramp_prefix && file_name_absolute_p (argv[i]))
1859             quote_argument (emacs_socket, tramp_prefix);
1860           quote_argument (emacs_socket, argv[i]);
1861           send_to_emacs (emacs_socket, " ");
1862         }
1863     }
1864   else if (eval)
1865     {
1866       /* Read expressions interactively.  */
1867       while ((str = fgets (string, BUFSIZ, stdin)))
1868         {
1869           send_to_emacs (emacs_socket, "-eval ");
1870           quote_argument (emacs_socket, str);
1871         }
1872       send_to_emacs (emacs_socket, " ");
1873     }
1874
1875   send_to_emacs (emacs_socket, "\n");
1876
1877   /* Wait for an answer. */
1878   if (!eval && !tty && !nowait && !quiet)
1879     {
1880       printf ("Waiting for Emacs...");
1881       needlf = 2;
1882     }
1883   fflush (stdout);
1884   while (fdatasync (1) != 0 && errno == EINTR)
1885     continue;
1886
1887   /* Now, wait for an answer and print any messages.  */
1888   while (exit_status == EXIT_SUCCESS)
1889     {
1890       char *p, *end_p;
1891       do
1892         {
1893           errno = 0;
1894           rl = recv (emacs_socket, string, BUFSIZ, 0);
1895         }
1896       /* If we receive a signal (e.g. SIGWINCH, which we pass
1897          through to Emacs), on some OSes we get EINTR and must retry. */
1898       while (rl < 0 && errno == EINTR);
1899
1900       if (rl <= 0)
1901         break;
1902
1903       string[rl] = '\0';
1904
1905       /* Loop over all NL-terminated messages.  */
1906       for (end_p = p = string; end_p != NULL && *end_p != '\0'; p = end_p)
1907         {
1908           end_p = strchr (p, '\n');
1909           if (end_p != NULL)
1910             *end_p++ = '\0';
1911
1912           if (strprefix ("-emacs-pid ", p))
1913             {
1914               /* -emacs-pid PID: The process id of the Emacs process. */
1915               emacs_pid = strtol (p + strlen ("-emacs-pid"), NULL, 10);
1916             }
1917           else if (strprefix ("-window-system-unsupported ", p))
1918             {
1919               /* -window-system-unsupported: Emacs was compiled without support
1920                  for whatever window system we tried.  Try the alternate
1921                  display, or, failing that, try the terminal.  */
1922               if (alt_display)
1923                 {
1924                   display = alt_display;
1925                   alt_display = NULL;
1926                 }
1927               else
1928                 {
1929                   nowait = 0;
1930                   tty = 1;
1931                 }
1932
1933               goto retry;
1934             }
1935           else if (strprefix ("-print ", p))
1936             {
1937               /* -print STRING: Print STRING on the terminal. */
1938               if (!suppress_output)
1939                 {
1940                   str = unquote_argument (p + strlen ("-print "));
1941                   if (needlf)
1942                     printf ("\n");
1943                   printf ("%s", str);
1944                   needlf = str[0] == '\0' ? needlf : str[strlen (str) - 1] != '\n';
1945                 }
1946             }
1947           else if (strprefix ("-print-nonl ", p))
1948             {
1949               /* -print-nonl STRING: Print STRING on the terminal.
1950                  Used to continue a preceding -print command.  */
1951               if (!suppress_output)
1952                 {
1953                   str = unquote_argument (p + strlen ("-print-nonl "));
1954                   printf ("%s", str);
1955                   needlf = str[0] == '\0' ? needlf : str[strlen (str) - 1] != '\n';
1956                 }
1957             }
1958           else if (strprefix ("-error ", p))
1959             {
1960               /* -error DESCRIPTION: Signal an error on the terminal. */
1961               str = unquote_argument (p + strlen ("-error "));
1962               if (needlf)
1963                 printf ("\n");
1964               fprintf (stderr, "*ERROR*: %s", str);
1965               needlf = str[0] == '\0' ? needlf : str[strlen (str) - 1] != '\n';
1966               exit_status = EXIT_FAILURE;
1967             }
1968 #ifdef SIGSTOP
1969           else if (strprefix ("-suspend ", p))
1970             {
1971               /* -suspend: Suspend this terminal, i.e., stop the process. */
1972               if (needlf)
1973                 printf ("\n");
1974               needlf = 0;
1975               kill (0, SIGSTOP);
1976             }
1977 #endif
1978           else
1979             {
1980               /* Unknown command. */
1981               if (needlf)
1982                 printf ("\n");
1983               needlf = 0;
1984               printf ("*ERROR*: Unknown message: %s\n", p);
1985             }
1986         }
1987     }
1988
1989   if (needlf)
1990     printf ("\n");
1991   fflush (stdout);
1992   while (fdatasync (1) != 0 && errno == EINTR)
1993     continue;
1994
1995   if (rl < 0)
1996     exit_status = EXIT_FAILURE;
1997
1998   CLOSE_SOCKET (emacs_socket);
1999   return exit_status;
2000 }
2001
2002 #endif /* HAVE_SOCKETS && HAVE_INET_SOCKETS */