lib-src/emacsclient.c

   1 /* Client process that communicates with GNU Emacs acting as server.
   2    Copyright (C) 1986, 1987, 1994, 1999, 2000, 2001, 2003
   3    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 2, or (at your option)
  10 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; see the file COPYING.  If not, write to
  19 the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  20 Boston, MA 02111-1307, USA.  */
  21
  22
  23 #define NO_SHORTNAMES
  24
  25 #ifdef HAVE_CONFIG_H
  26 #include <config.h>
  27 #endif
  28
  29 #undef signal
  30
  31 #include <ctype.h>
  32 #include <stdio.h>
  33 #include <getopt.h>
  34 #ifdef HAVE_UNISTD_H
  35 #include <unistd.h>
  36 #endif
  37
  38 #ifdef VMS
  39 # include "vms-pwd.h"
  40 #else
  41 # include <pwd.h>
  42 #endif /* not VMS */
  43
  44 #include <signal.h>
  45 #include <errno.h>
  46
  47 \f
  48 char *getenv (), *getwd ();
  49 char *getcwd ();
  50
  51 /* This is defined with -D from the compilation command,
  52    which extracts it from ../lisp/version.el.  */
  53
  54 #ifndef VERSION
  55 #define VERSION "unspecified"
  56 #endif
  57 \f
  58 /* Name used to invoke this program.  */
  59 char *progname;
  60
  61 /* The first argument to main. */
  62 int main_argc;
  63
  64 /* The second argument to main. */
  65 char **main_argv;
  66
  67 /* Nonzero means don't wait for a response from Emacs.  --no-wait.  */
  68 int nowait = 0;
  69
  70 /* Nonzero means args are expressions to be evaluated.  --eval.  */
  71 int eval = 0;
  72
  73 /* The display on which Emacs should work.  --display.  */
  74 char *display = NULL;
  75
  76 /* Nonzero means open a new Emacs frame on the current terminal. */
  77 int frame = 0;
  78
  79 /* If non-NULL, the name of an editor to fallback to if the server
  80    is not running.  --alternate-editor.   */
  81 const char * alternate_editor = NULL;
  82
  83 /* If non-NULL, the filename of the UNIX socket.  */
  84 char *socket_name = NULL;
  85
  86 void print_help_and_exit ();
  87
  88 struct option longopts[] =
  89 {
  90   { "no-wait",  no_argument,       NULL, 'n' },
  91   { "eval",     no_argument,       NULL, 'e' },
  92   { "help",     no_argument,       NULL, 'H' },
  93   { "version",  no_argument,       NULL, 'V' },
  94   { "tty",      no_argument,       NULL, 't' },
  95   { "alternate-editor", required_argument, NULL, 'a' },
  96   { "socket-name",      required_argument, NULL, 's' },
  97   { "display",  required_argument, NULL, 'd' },
  98   { 0, 0, 0, 0 }
  99 };
 100
 101 /* Decode the options from argv and argc.
 102    The global variable `optind' will say how many arguments we used up.  */
 103
 104 void
 105 decode_options (argc, argv)
 106      int argc;
 107      char **argv;
 108 {
 109   while (1)
 110     {
 111       int opt = getopt_long (argc, argv,
 112                              "VHnea:s:d:t", longopts, 0);
 113
 114       if (opt == EOF)
 115         break;
 116
 117       alternate_editor = getenv ("ALTERNATE_EDITOR");
 118
 119       switch (opt)
 120         {
 121         case 0:
 122           /* If getopt returns 0, then it has already processed a
 123              long-named option.  We should do nothing.  */
 124           break;
 125
 126         case 'a':
 127           alternate_editor = optarg;
 128           break;
 129
 130         case 's':
 131           socket_name = optarg;
 132           break;
 133
 134         case 'd':
 135           display = optarg;
 136           break;
 137
 138         case 'n':
 139           nowait = 1;
 140           break;
 141
 142         case 'e':
 143           eval = 1;
 144           break;
 145
 146         case 'V':
 147           printf ("emacsclient %s\n", VERSION);
 148           exit (0);
 149           break;
 150
 151         case 't':
 152           frame = 1;
 153           break;
 154
 155         case 'H':
 156           print_help_and_exit ();
 157           break;
 158
 159         default:
 160           fprintf (stderr, "Try `%s --help' for more information\n", progname);
 161           exit (1);
 162           break;
 163         }
 164     }
 165
 166   if (frame) {
 167     nowait = 0;
 168     display = 0;
 169   }
 170
 171 }
 172
 173 void
 174 print_help_and_exit ()
 175 {
 176   printf (
 177           "Usage: %s [OPTIONS] FILE...\n\
 178 Tell the Emacs server to visit the specified files.\n\
 179 Every FILE can be either just a FILENAME or [+LINE[:COLUMN]] FILENAME.\n\
 180 \n\
 181 The following OPTIONS are accepted:\n\
 182 -V, --version           Just print a version info and return\n\
 183 -H, --help              Print this usage information message\n\
 184 -t, --tty               Open a new Emacs frame on the current terminal\n\
 185 -n, --no-wait           Don't wait for the server to return\n\
 186 -e, --eval              Evaluate the FILE arguments as ELisp expressions\n\
 187 -d, --display=DISPLAY   Visit the file in the given display\n\
 188 -s, --socket-name=FILENAME\n\
 189                         Set the filename of the UNIX socket for communication\n\
 190 -a, --alternate-editor=EDITOR\n\
 191                         Editor to fallback to if the server is not running\n\
 192 \n\
 193 Report bugs to bug-gnu-emacs@gnu.org.\n", progname);
 194   exit (0);
 195 }
 196
 197 /* In NAME, insert a & before each &, each space, each newline, and
 198    any initial -.  Change spaces to underscores, too, so that the
 199    return value never contains a space.  */
 200
 201 void
 202 quote_file_name (name, stream)
 203      char *name;
 204      FILE *stream;
 205 {
 206   char *copy = (char *) malloc (strlen (name) * 2 + 1);
 207   char *p, *q;
 208
 209   p = name;
 210   q = copy;
 211   while (*p)
 212     {
 213       if (*p == ' ')
 214         {
 215           *q++ = '&';
 216           *q++ = '_';
 217           p++;
 218         }
 219       else if (*p == '\n')
 220         {
 221           *q++ = '&';
 222           *q++ = 'n';
 223           p++;
 224         }
 225       else
 226         {
 227           if (*p == '&' || (*p == '-' && p == name))
 228             *q++ = '&';
 229           *q++ = *p++;
 230         }
 231     }
 232   *q++ = 0;
 233
 234   fprintf (stream, copy);
 235
 236   free (copy);
 237 }
 238
 239 /* Like malloc but get fatal error if memory is exhausted.  */
 240
 241 long *
 242 xmalloc (size)
 243      unsigned int size;
 244 {
 245   long *result = (long *) malloc (size);
 246   if (result == NULL)
 247   {
 248     perror ("malloc");
 249     exit (1);
 250   }
 251   return result;
 252 }
 253 \f
 254 /*
 255   Try to run a different command, or --if no alternate editor is
 256   defined-- exit with an errorcode.
 257 */
 258 void
 259 fail (void)
 260 {
 261   if (alternate_editor)
 262     {
 263       int i = optind - 1;
 264       execvp (alternate_editor, main_argv + i);
 265       return;
 266     }
 267   else
 268     {
 269       exit (1);
 270     }
 271 }
 272
 273 int emacs_pid;
 274
 275 #ifdef nec_ews_svr4
 276 extern char *_sobuf ;
 277 #else
 278 #if defined (USG) || defined (DGUX)
 279 unsigned char _sobuf[BUFSIZ+8];
 280 #else
 281 char _sobuf[BUFSIZ];
 282 #endif
 283 #endif
 284
 285 SIGTYPE
 286 pass_signal_to_emacs (int signalnum)
 287 {
 288   int old_errno = errno;
 289
 290   if (emacs_pid)
 291     kill (emacs_pid, signalnum);
 292
 293   signal (signalnum, pass_signal_to_emacs);
 294   errno = old_errno;
 295 }
 296
 297 void
 298 init_signals (void)
 299 {
 300   /* Set up signal handlers. */
 301   signal (SIGWINCH, pass_signal_to_emacs);
 302
 303   /* Don't pass SIGINT and SIGQUIT to Emacs, because it has no way of
 304      deciding which terminal the signal came from.  C-g is now a
 305      normal input event on secondary terminals.  */
 306 #if 0
 307   signal (SIGINT, pass_signal_to_emacs);
 308   signal (SIGQUIT, pass_signal_to_emacs);
 309 #endif
 310 }
 311
 312 \f
 313 #if !defined (HAVE_SOCKETS) || defined (NO_SOCKETS_IN_FILE_SYSTEM)
 314
 315 int
 316 main (argc, argv)
 317      int argc;
 318      char **argv;
 319 {
 320   fprintf (stderr, "%s: Sorry, the Emacs server is supported only\n",
 321            argv[0]);
 322   fprintf (stderr, "on systems with Berkeley sockets.\n");
 323
 324   fail ();
 325 }
 326
 327 #else /* HAVE_SOCKETS */
 328
 329 #include <sys/types.h>
 330 #include <sys/socket.h>
 331 #include <sys/un.h>
 332 #include <sys/stat.h>
 333 #include <errno.h>
 334
 335 extern char *strerror ();
 336 extern int errno;
 337
 338 /* Three possibilities:
 339    2 - can't be `stat'ed                (sets errno)
 340    1 - isn't owned by us
 341    0 - success: none of the above */
 342
 343 static int
 344 socket_status (socket_name)
 345      char *socket_name;
 346 {
 347   struct stat statbfr;
 348
 349   if (stat (socket_name, &statbfr) == -1)
 350     return 2;
 351
 352   if (statbfr.st_uid != geteuid ())
 353     return 1;
 354
 355   return 0;
 356 }
 357
 358 /* Returns 1 if PREFIX is a prefix of STRING. */
 359 static int
 360 strprefix (char *prefix, char *string)
 361 {
 362   int i;
 363   if (! prefix)
 364     return 1;
 365
 366   if (!string)
 367     return 0;
 368
 369   for (i = 0; prefix[i]; i++)
 370     if (!string[i] || string[i] != prefix[i])
 371       return 0;
 372   return 1;
 373 }
 374
 375 int
 376 main (argc, argv)
 377      int argc;
 378      char **argv;
 379 {
 380   char *system_name;
 381   int system_name_length;
 382   int s, i, needlf = 0;
 383   FILE *out, *in;
 384   struct sockaddr_un server;
 385   char *cwd, *str;
 386   char string[BUFSIZ];
 387
 388   main_argc = argc;
 389   main_argv = argv;
 390   progname = argv[0];
 391
 392   /* Process options.  */
 393   decode_options (argc, argv);
 394
 395   if ((argc - optind < 1) && !eval && !frame)
 396     {
 397       fprintf (stderr, "%s: file name or argument required\n", progname);
 398       fprintf (stderr, "Try `%s --help' for more information\n", progname);
 399       exit (1);
 400     }
 401
 402   /*
 403    * Open up an AF_UNIX socket in this person's home directory
 404    */
 405
 406   if ((s = socket (AF_UNIX, SOCK_STREAM, 0)) < 0)
 407     {
 408       fprintf (stderr, "%s: ", argv[0]);
 409       perror ("socket");
 410       fail ();
 411     }
 412
 413   server.sun_family = AF_UNIX;
 414
 415   {
 416     char *dot;
 417     system_name_length = 32;
 418
 419     while (1)
 420       {
 421         system_name = (char *) xmalloc (system_name_length + 1);
 422
 423         /* system_name must be null-terminated string.  */
 424         system_name[system_name_length] = '\0';
 425
 426         if (gethostname (system_name, system_name_length) == 0)
 427           break;
 428
 429         free (system_name);
 430         system_name_length *= 2;
 431       }
 432
 433     /* We always use the non-dotted host name, for simplicity.  */
 434     dot = index (system_name, '.');
 435     if (dot)
 436       *dot = '\0';
 437   }
 438
 439   {
 440     int sock_status = 0;
 441     int saved_errno = 0;
 442
 443     if (! socket_name)
 444       {
 445         socket_name = alloca (system_name_length + 100);
 446         sprintf (socket_name, "/tmp/emacs%d-%s/server",
 447                  (int) geteuid (), system_name);
 448       }
 449
 450     if (strlen (socket_name) < sizeof (server.sun_path))
 451       strcpy (server.sun_path, socket_name);
 452     else
 453       {
 454         fprintf (stderr, "%s: socket-name %s too long",
 455                  argv[0], socket_name);
 456         fail ();
 457       }
 458
 459     /* See if the socket exists, and if it's owned by us. */
 460     sock_status = socket_status (server.sun_path);
 461     saved_errno = errno;
 462     if (sock_status)
 463       {
 464         /* Failing that, see if LOGNAME or USER exist and differ from
 465            our euid.  If so, look for a socket based on the UID
 466            associated with the name.  This is reminiscent of the logic
 467            that init_editfns uses to set the global Vuser_full_name.  */
 468
 469         char *user_name = (char *) getenv ("LOGNAME");
 470         if (!user_name)
 471           user_name = (char *) getenv ("USER");
 472
 473         if (user_name)
 474           {
 475             struct passwd *pw = getpwnam (user_name);
 476             if (pw && (pw->pw_uid != geteuid ()))
 477               {
 478                 /* We're running under su, apparently. */
 479                 sprintf (server.sun_path, "/tmp/emacs%d-%s/server",
 480                          (int) pw->pw_uid, system_name);
 481                 sock_status = socket_status (server.sun_path);
 482                 saved_errno = errno;
 483               }
 484           }
 485       }
 486
 487      switch (sock_status)
 488        {
 489        case 1:
 490          /* There's a socket, but it isn't owned by us.  This is OK if
 491             we are root. */
 492          if (0 != geteuid ())
 493            {
 494              fprintf (stderr, "%s: Invalid socket owner\n", argv[0]);
 495              fail ();
 496            }
 497          break;
 498
 499        case 2:
 500          /* `stat' failed */
 501          if (saved_errno == ENOENT)
 502            fprintf (stderr,
 503                     "%s: Can't find socket; have you started the server?\n\
 504 To start the server in Emacs, type \"M-x server-start\".\n",
 505                     argv[0]);
 506          else
 507            fprintf (stderr, "%s: Can't stat %s: %s\n",
 508                     argv[0], server.sun_path, strerror (saved_errno));
 509          fail ();
 510          break;
 511        }
 512   }
 513
 514   if (connect (s, (struct sockaddr *) &server, strlen (server.sun_path) + 2)
 515       < 0)
 516     {
 517       fprintf (stderr, "%s: ", argv[0]);
 518       perror ("connect");
 519       fail ();
 520     }
 521
 522   /* We use the stream OUT to send our command to the server.  */
 523   if ((out = fdopen (s, "r+")) == NULL)
 524     {
 525       fprintf (stderr, "%s: ", argv[0]);
 526       perror ("fdopen");
 527       fail ();
 528     }
 529
 530   /* We use the stream IN to read the response.
 531      We used to use just one stream for both output and input
 532      on the socket, but reversing direction works nonportably:
 533      on some systems, the output appears as the first input;
 534      on other systems it does not.  */
 535   if ((in = fdopen (s, "r+")) == NULL)
 536     {
 537       fprintf (stderr, "%s: ", argv[0]);
 538       perror ("fdopen");
 539       fail ();
 540     }
 541
 542 #ifdef HAVE_GETCWD
 543   cwd = getcwd (string, sizeof string);
 544 #else
 545   cwd = getwd (string);
 546 #endif
 547   if (cwd == 0)
 548     {
 549       /* getwd puts message in STRING if it fails.  */
 550
 551 #ifdef HAVE_GETCWD
 552       fprintf (stderr, "%s: %s (%s)\n", argv[0],
 553                "Cannot get current working directory", strerror (errno));
 554 #else
 555       fprintf (stderr, "%s: %s (%s)\n", argv[0], string, strerror (errno));
 556 #endif
 557       fail ();
 558     }
 559
 560   if (nowait)
 561     fprintf (out, "-nowait ");
 562
 563   if (eval)
 564     fprintf (out, "-eval ");
 565
 566   if (display)
 567     {
 568       fprintf (out, "-display ");
 569       quote_file_name (display, out);
 570       fprintf (out, " ");
 571     }
 572
 573   if (frame)
 574     {
 575       char *tty_name = ttyname (fileno (stdin));
 576       if (! tty_name)
 577         fail ();
 578
 579       init_signals ();
 580
 581       fprintf (out, "-tty ");
 582       quote_file_name (tty_name, out);
 583       fprintf (out, " ");
 584       quote_file_name (getenv("TERM"), out);
 585       fprintf (out, " ");
 586     }
 587
 588   if ((argc - optind > 0))
 589     {
 590       for (i = optind; i < argc; i++)
 591         {
 592           if (eval)
 593             ; /* Don't prepend any cwd or anything like that.  */
 594           else if (*argv[i] == '+')
 595             {
 596               char *p = argv[i] + 1;
 597               while (isdigit ((unsigned char) *p) || *p == ':') p++;
 598               if (*p != 0)
 599                 {
 600                   quote_file_name (cwd, out);
 601                   fprintf (out, "/");
 602                 }
 603             }
 604           else if (*argv[i] != '/')
 605             {
 606               quote_file_name (cwd, out);
 607               fprintf (out, "/");
 608             }
 609
 610           quote_file_name (argv[i], out);
 611           fprintf (out, " ");
 612         }
 613     }
 614   else
 615     {
 616       if (!frame)
 617         {
 618           while ((str = fgets (string, BUFSIZ, stdin)))
 619             {
 620               quote_file_name (str, out);
 621             }
 622           fprintf (out, " ");
 623         }
 624     }
 625
 626   fprintf (out, "\n");
 627   fflush (out);
 628
 629   /* Maybe wait for an answer.   */
 630   if (nowait)
 631     {
 632       return 0;
 633     }
 634
 635   if (!eval && !frame)
 636     {
 637       printf ("Waiting for Emacs...");
 638       needlf = 2;
 639     }
 640   fflush (stdout);
 641
 642   /* Now, wait for an answer and print any messages.  */
 643   while ((str = fgets (string, BUFSIZ, in)))
 644     {
 645       if (frame)
 646         {
 647           if (strprefix ("emacs-pid ", str))
 648             {
 649               emacs_pid = strtol (string + strlen ("emacs-pid"), NULL, 10);
 650             }
 651         }
 652       else
 653         {
 654           if (needlf == 2)
 655             printf ("\n");
 656           printf ("%s", str);
 657           needlf = str[0] == '\0' ? needlf : str[strlen (str) - 1] != '\n';
 658         }
 659     }
 660
 661   if (needlf)
 662     printf ("\n");
 663   fflush (stdout);
 664
 665   return 0;
 666 }
 667
 668 #endif /* HAVE_SOCKETS */
 669 \f
 670 #ifndef HAVE_STRERROR
 671 char *
 672 strerror (errnum)
 673      int errnum;
 674 {
 675   extern char *sys_errlist[];
 676   extern int sys_nerr;
 677
 678   if (errnum >= 0 && errnum < sys_nerr)
 679     return sys_errlist[errnum];
 680   return (char *) "Unknown error";
 681 }
 682
 683 #endif /* ! HAVE_STRERROR */
 684
 685 /* arch-tag: f39bb9c4-73eb-477e-896d-50832e2ca9a7
 686    (do not change this comment) */