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 window_change_signal (int signalnum)
 287 {
 288   int old_errno = errno;
 289
 290   if (emacs_pid)
 291     kill (emacs_pid, SIGWINCH);
 292
 293   signal (SIGWINCH, window_change_signal);
 294   errno = old_errno;
 295 }
 296
 297 void
 298 init_signals (void)
 299 {
 300   /* Set up signal handlers. */
 301   signal (SIGWINCH, window_change_signal);
 302 }
 303
 304 \f
 305 #if !defined (HAVE_SOCKETS) || defined (NO_SOCKETS_IN_FILE_SYSTEM)
 306
 307 int
 308 main (argc, argv)
 309      int argc;
 310      char **argv;
 311 {
 312   fprintf (stderr, "%s: Sorry, the Emacs server is supported only\n",
 313            argv[0]);
 314   fprintf (stderr, "on systems with Berkeley sockets.\n");
 315
 316   fail ();
 317 }
 318
 319 #else /* HAVE_SOCKETS */
 320
 321 #include <sys/types.h>
 322 #include <sys/socket.h>
 323 #include <sys/un.h>
 324 #include <sys/stat.h>
 325 #include <errno.h>
 326
 327 extern char *strerror ();
 328 extern int errno;
 329
 330 /* Three possibilities:
 331    2 - can't be `stat'ed                (sets errno)
 332    1 - isn't owned by us
 333    0 - success: none of the above */
 334
 335 static int
 336 socket_status (socket_name)
 337      char *socket_name;
 338 {
 339   struct stat statbfr;
 340
 341   if (stat (socket_name, &statbfr) == -1)
 342     return 2;
 343
 344   if (statbfr.st_uid != geteuid ())
 345     return 1;
 346
 347   return 0;
 348 }
 349
 350 /* Returns 1 if PREFIX is a prefix of STRING. */
 351 static int
 352 strprefix (char *prefix, char *string)
 353 {
 354   int i;
 355   if (! prefix)
 356     return 1;
 357
 358   if (!string)
 359     return 0;
 360
 361   for (i = 0; prefix[i]; i++)
 362     if (!string[i] || string[i] != prefix[i])
 363       return 0;
 364   return 1;
 365 }
 366
 367 int
 368 main (argc, argv)
 369      int argc;
 370      char **argv;
 371 {
 372   char *system_name;
 373   int system_name_length;
 374   int s, i, needlf = 0;
 375   FILE *out, *in;
 376   struct sockaddr_un server;
 377   char *cwd, *str;
 378   char string[BUFSIZ];
 379
 380   main_argc = argc;
 381   main_argv = argv;
 382   progname = argv[0];
 383
 384   /* Process options.  */
 385   decode_options (argc, argv);
 386
 387   if ((argc - optind < 1) && !eval && !frame)
 388     {
 389       fprintf (stderr, "%s: file name or argument required\n", progname);
 390       fprintf (stderr, "Try `%s --help' for more information\n", progname);
 391       exit (1);
 392     }
 393
 394   /*
 395    * Open up an AF_UNIX socket in this person's home directory
 396    */
 397
 398   if ((s = socket (AF_UNIX, SOCK_STREAM, 0)) < 0)
 399     {
 400       fprintf (stderr, "%s: ", argv[0]);
 401       perror ("socket");
 402       fail ();
 403     }
 404
 405   server.sun_family = AF_UNIX;
 406
 407   {
 408     char *dot;
 409     system_name_length = 32;
 410
 411     while (1)
 412       {
 413         system_name = (char *) xmalloc (system_name_length + 1);
 414
 415         /* system_name must be null-terminated string.  */
 416         system_name[system_name_length] = '\0';
 417
 418         if (gethostname (system_name, system_name_length) == 0)
 419           break;
 420
 421         free (system_name);
 422         system_name_length *= 2;
 423       }
 424
 425     /* We always use the non-dotted host name, for simplicity.  */
 426     dot = index (system_name, '.');
 427     if (dot)
 428       *dot = '\0';
 429   }
 430
 431   {
 432     int sock_status = 0;
 433     int oerrno = 0;
 434
 435     if (! socket_name)
 436       {
 437         socket_name = alloca (system_name_length + 100);
 438         sprintf (socket_name, "/tmp/emacs%d-%s/server",
 439                  (int) geteuid (), system_name);
 440       }
 441
 442     if (strlen (socket_name) < sizeof (server.sun_path))
 443       strcpy (server.sun_path, socket_name);
 444     else
 445       {
 446         fprintf (stderr, "%s: socket-name %s too long",
 447                  argv[0], socket_name);
 448         fail ();
 449       }
 450
 451     /* See if the socket exists, and if it's owned by us. */
 452     sock_status = socket_status (server.sun_path);
 453     oerrno = errno;
 454     if (sock_status)
 455       {
 456         /* Failing that, see if LOGNAME or USER exist and differ from
 457            our euid.  If so, look for a socket based on the UID
 458            associated with the name.  This is reminiscent of the logic
 459            that init_editfns uses to set the global Vuser_full_name.  */
 460
 461         char *user_name = (char *) getenv ("LOGNAME");
 462         if (!user_name)
 463           user_name = (char *) getenv ("USER");
 464
 465         if (user_name)
 466           {
 467             struct passwd *pw = getpwnam (user_name);
 468             if (pw && (pw->pw_uid != geteuid ()))
 469               {
 470                 /* We're running under su, apparently. */
 471                 sprintf (server.sun_path, "/tmp/esrv%d-%s",
 472                          (int) pw->pw_uid, system_name);
 473                 sock_status = socket_status (server.sun_path);
 474                 oerrno = errno;
 475               }
 476           }
 477       }
 478
 479      switch (sock_status)
 480        {
 481        case 1:
 482          /* There's a socket, but it isn't owned by us.  This is OK if
 483             we are root. */
 484          if (0 != geteuid ())
 485            {
 486              fprintf (stderr, "%s: Invalid socket owner\n", argv[0]);
 487              fail ();
 488            }
 489          break;
 490
 491        case 2:
 492          /* `stat' failed */
 493          if (errno == ENOENT)
 494            fprintf (stderr,
 495                     "%s: Can't find socket; have you started the server?\n\
 496 To start the server in Emacs, type \"M-x server-start\".\n",
 497                     argv[0]);
 498          else
 499            fprintf (stderr, "%s: Can't stat %s: %s\n",
 500                     argv[0], server.sun_path, strerror (oerrno));
 501          fail ();
 502          break;
 503        }
 504   }
 505
 506   if (connect (s, (struct sockaddr *) &server, strlen (server.sun_path) + 2)
 507       < 0)
 508     {
 509       fprintf (stderr, "%s: ", argv[0]);
 510       perror ("connect");
 511       fail ();
 512     }
 513
 514   /* We use the stream OUT to send our command to the server.  */
 515   if ((out = fdopen (s, "r+")) == NULL)
 516     {
 517       fprintf (stderr, "%s: ", argv[0]);
 518       perror ("fdopen");
 519       fail ();
 520     }
 521
 522   /* We use the stream IN to read the response.
 523      We used to use just one stream for both output and input
 524      on the socket, but reversing direction works nonportably:
 525      on some systems, the output appears as the first input;
 526      on other systems it does not.  */
 527   if ((in = fdopen (s, "r+")) == NULL)
 528     {
 529       fprintf (stderr, "%s: ", argv[0]);
 530       perror ("fdopen");
 531       fail ();
 532     }
 533
 534 #ifdef HAVE_GETCWD
 535   cwd = getcwd (string, sizeof string);
 536 #else
 537   cwd = getwd (string);
 538 #endif
 539   if (cwd == 0)
 540     {
 541       /* getwd puts message in STRING if it fails.  */
 542
 543 #ifdef HAVE_GETCWD
 544       fprintf (stderr, "%s: %s (%s)\n", argv[0],
 545                "Cannot get current working directory", strerror (errno));
 546 #else
 547       fprintf (stderr, "%s: %s (%s)\n", argv[0], string, strerror (errno));
 548 #endif
 549       fail ();
 550     }
 551
 552   if (nowait)
 553     fprintf (out, "-nowait ");
 554
 555   if (eval)
 556     fprintf (out, "-eval ");
 557
 558   if (display)
 559     {
 560       fprintf (out, "-display ");
 561       quote_file_name (display, out);
 562       fprintf (out, " ");
 563     }
 564
 565   if (frame)
 566     {
 567       char *tty_name = ttyname (fileno (stdin));
 568       if (! tty_name)
 569         fail ();
 570
 571       init_signals ();
 572
 573       fprintf (out, "-tty ");
 574       quote_file_name (tty_name, out);
 575       fprintf (out, " ");
 576       quote_file_name (getenv("TERM"), out);
 577       fprintf (out, " ");
 578     }
 579
 580   if ((argc - optind > 0))
 581     {
 582       for (i = optind; i < argc; i++)
 583         {
 584           if (eval)
 585             ; /* Don't prepend any cwd or anything like that.  */
 586           else if (*argv[i] == '+')
 587             {
 588               char *p = argv[i] + 1;
 589               while (isdigit ((unsigned char) *p) || *p == ':') p++;
 590               if (*p != 0)
 591                 {
 592                   quote_file_name (cwd, out);
 593                   fprintf (out, "/");
 594                 }
 595             }
 596           else if (*argv[i] != '/')
 597             {
 598               quote_file_name (cwd, out);
 599               fprintf (out, "/");
 600             }
 601
 602           quote_file_name (argv[i], out);
 603           fprintf (out, " ");
 604         }
 605     }
 606   else
 607     {
 608       if (!frame)
 609         {
 610           while ((str = fgets (string, BUFSIZ, stdin)))
 611             {
 612               quote_file_name (str, out);
 613             }
 614           fprintf (out, " ");
 615         }
 616     }
 617
 618   fprintf (out, "\n");
 619   fflush (out);
 620
 621   /* Maybe wait for an answer.   */
 622   if (nowait)
 623     {
 624       return 0;
 625     }
 626
 627   if (!eval && !frame)
 628     {
 629       printf ("Waiting for Emacs...");
 630       needlf = 2;
 631     }
 632   fflush (stdout);
 633
 634   /* Now, wait for an answer and print any messages.  */
 635   while ((str = fgets (string, BUFSIZ, in)))
 636     {
 637       if (frame)
 638         {
 639           if (strprefix ("emacs-pid ", str))
 640             {
 641               emacs_pid = strtol (string + strlen ("emacs-pid"), NULL, 10);
 642             }
 643         }
 644       else
 645         {
 646           if (needlf == 2)
 647             printf ("\n");
 648           printf ("%s", str);
 649           needlf = str[0] == '\0' ? needlf : str[strlen (str) - 1] != '\n';
 650         }
 651     }
 652
 653   if (needlf)
 654     printf ("\n");
 655   fflush (stdout);
 656
 657   return 0;
 658 }
 659
 660 #endif /* HAVE_SOCKETS */
 661 \f
 662 #ifndef HAVE_STRERROR
 663 char *
 664 strerror (errnum)
 665      int errnum;
 666 {
 667   extern char *sys_errlist[];
 668   extern int sys_nerr;
 669
 670   if (errnum >= 0 && errnum < sys_nerr)
 671     return sys_errlist[errnum];
 672   return (char *) "Unknown error";
 673 }
 674
 675 #endif /* ! HAVE_STRERROR */
 676
 677 /* arch-tag: f39bb9c4-73eb-477e-896d-50832e2ca9a7
 678    (do not change this comment) */