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 char *getenv (), *getwd ();
  45 char *getcwd ();
  46
  47 /* This is defined with -D from the compilation command,
  48    which extracts it from ../lisp/version.el.  */
  49
  50 #ifndef VERSION
  51 #define VERSION "unspecified"
  52 #endif
  53 \f
  54 /* Name used to invoke this program.  */
  55 char *progname;
  56
  57 /* Nonzero means don't wait for a response from Emacs.  --no-wait.  */
  58 int nowait = 0;
  59
  60 /* Nonzero means args are expressions to be evaluated.  --eval.  */
  61 int eval = 0;
  62
  63 /* The display on which Emacs should work.  --display.  */
  64 char *display = NULL;
  65
  66 /* If non-NULL, the name of an editor to fallback to if the server
  67    is not running.  --alternate-editor.   */
  68 const char * alternate_editor = NULL;
  69
  70 /* If non-NULL, thefilename of the UNIX socket */
  71 char *socket_name = NULL;
  72
  73 void print_help_and_exit ();
  74
  75 struct option longopts[] =
  76 {
  77   { "no-wait",  no_argument,       NULL, 'n' },
  78   { "eval",     no_argument,       NULL, 'e' },
  79   { "help",     no_argument,       NULL, 'H' },
  80   { "version",  no_argument,       NULL, 'V' },
  81   { "alternate-editor", required_argument, NULL, 'a' },
  82   { "socket-name",      required_argument, NULL, 's' },
  83   { "display",  required_argument, NULL, 'd' },
  84   { 0, 0, 0, 0 }
  85 };
  86
  87 /* Decode the options from argv and argc.
  88    The global variable `optind' will say how many arguments we used up.  */
  89
  90 void
  91 decode_options (argc, argv)
  92      int argc;
  93      char **argv;
  94 {
  95   while (1)
  96     {
  97       int opt = getopt_long (argc, argv,
  98                              "VHnea:s:d:", longopts, 0);
  99
 100       if (opt == EOF)
 101         break;
 102
 103       alternate_editor = getenv ("ALTERNATE_EDITOR");
 104
 105       switch (opt)
 106         {
 107         case 0:
 108           /* If getopt returns 0, then it has already processed a
 109              long-named option.  We should do nothing.  */
 110           break;
 111
 112         case 'a':
 113           alternate_editor = optarg;
 114           break;
 115
 116         case 's':
 117           socket_name = optarg;
 118           break;
 119
 120         case 'd':
 121           display = optarg;
 122           break;
 123
 124         case 'n':
 125           nowait = 1;
 126           break;
 127
 128         case 'e':
 129           eval = 1;
 130           break;
 131
 132         case 'V':
 133           printf ("emacsclient %s\n", VERSION);
 134           exit (0);
 135           break;
 136
 137         case 'H':
 138           print_help_and_exit ();
 139           break;
 140
 141         default:
 142           fprintf (stderr, "Try `%s --help' for more information\n", progname);
 143           exit (1);
 144           break;
 145         }
 146     }
 147 }
 148
 149 void
 150 print_help_and_exit ()
 151 {
 152   printf (
 153           "Usage: %s [OPTIONS] FILE...\n\
 154 Tell the Emacs server to visit the specified files.\n\
 155 Every FILE can be either just a FILENAME or [+LINE[:COLUMN]] FILENAME.\n\
 156 \n\
 157 The following OPTIONS are accepted:\n\
 158 -V, --version           Just print a version info and return\n\
 159 -H, --help              Print this usage information message\n\
 160 -n, --no-wait           Don't wait for the server to return\n\
 161 -e, --eval              Evaluate the FILE arguments as ELisp expressions\n\
 162 -d, --display=DISPLAY   Visit the file in the given display\n\
 163 -s, --socket-name=FILENAME\n\
 164                         Set the filename of the UNIX socket for communication\n\
 165 -a, --alternate-editor=EDITOR\n\
 166                         Editor to fallback to if the server is not running\n\
 167 \n\
 168 Report bugs to bug-gnu-emacs@gnu.org.\n", progname);
 169   exit (0);
 170 }
 171
 172 /* Return a copy of NAME, inserting a &
 173    before each &, each space, each newline, and any initial -.
 174    Change spaces to underscores, too, so that the
 175    return value never contains a space.  */
 176
 177 char *
 178 quote_file_name (name)
 179      char *name;
 180 {
 181   char *copy = (char *) malloc (strlen (name) * 2 + 1);
 182   char *p, *q;
 183
 184   p = name;
 185   q = copy;
 186   while (*p)
 187     {
 188       if (*p == ' ')
 189         {
 190           *q++ = '&';
 191           *q++ = '_';
 192           p++;
 193         }
 194       else if (*p == '\n')
 195         {
 196           *q++ = '&';
 197           *q++ = 'n';
 198           p++;
 199         }
 200       else
 201         {
 202           if (*p == '&' || (*p == '-' && p == name))
 203             *q++ = '&';
 204           *q++ = *p++;
 205         }
 206     }
 207   *q++ = 0;
 208
 209   return copy;
 210 }
 211
 212 /* Like malloc but get fatal error if memory is exhausted.  */
 213
 214 long *
 215 xmalloc (size)
 216      unsigned int size;
 217 {
 218   long *result = (long *) malloc (size);
 219   if (result == NULL)
 220   {
 221     perror ("malloc");
 222     exit (1);
 223   }
 224   return result;
 225 }
 226 \f
 227 /*
 228   Try to run a different command, or --if no alternate editor is
 229   defined-- exit with an errorcode.
 230 */
 231 void
 232 fail (argc, argv)
 233      int argc;
 234      char **argv;
 235 {
 236   if (alternate_editor)
 237     {
 238       int i = optind - 1;
 239       execvp (alternate_editor, argv + i);
 240       return;
 241     }
 242   else
 243     {
 244       exit (1);
 245     }
 246 }
 247
 248
 249 \f
 250 #if !defined (HAVE_SOCKETS) || defined (NO_SOCKETS_IN_FILE_SYSTEM)
 251
 252 int
 253 main (argc, argv)
 254      int argc;
 255      char **argv;
 256 {
 257   fprintf (stderr, "%s: Sorry, the Emacs server is supported only\n",
 258            argv[0]);
 259   fprintf (stderr, "on systems with Berkeley sockets.\n");
 260
 261   fail (argc, argv);
 262 }
 263
 264 #else /* HAVE_SOCKETS */
 265
 266 #include <sys/types.h>
 267 #include <sys/socket.h>
 268 #include <sys/un.h>
 269 #include <sys/stat.h>
 270 #include <errno.h>
 271
 272 extern char *strerror ();
 273 extern int errno;
 274
 275 /* Three possibilities:
 276    2 - can't be `stat'ed                (sets errno)
 277    1 - isn't owned by us
 278    0 - success: none of the above */
 279
 280 static int
 281 socket_status (socket_name)
 282      char *socket_name;
 283 {
 284   struct stat statbfr;
 285
 286   if (stat (socket_name, &statbfr) == -1)
 287     return 2;
 288
 289   if (statbfr.st_uid != geteuid ())
 290     return 1;
 291
 292   return 0;
 293 }
 294
 295 int
 296 main (argc, argv)
 297      int argc;
 298      char **argv;
 299 {
 300   char *system_name;
 301   int system_name_length;
 302   int s, i, needlf = 0;
 303   FILE *out, *in;
 304   struct sockaddr_un server;
 305   char *cwd, *str;
 306   char string[BUFSIZ];
 307
 308   progname = argv[0];
 309
 310   /* Process options.  */
 311   decode_options (argc, argv);
 312
 313   if (argc - optind < 1)
 314     {
 315       fprintf (stderr, "%s: file name or argument required\n", progname);
 316       fprintf (stderr, "Try `%s --help' for more information\n", progname);
 317       exit (1);
 318     }
 319
 320   /*
 321    * Open up an AF_UNIX socket in this person's home directory
 322    */
 323
 324   if ((s = socket (AF_UNIX, SOCK_STREAM, 0)) < 0)
 325     {
 326       fprintf (stderr, "%s: ", argv[0]);
 327       perror ("socket");
 328       fail (argc, argv);
 329     }
 330
 331   server.sun_family = AF_UNIX;
 332
 333   {
 334     char *dot;
 335     system_name_length = 32;
 336
 337     while (1)
 338       {
 339         system_name = (char *) xmalloc (system_name_length + 1);
 340
 341         /* system_name must be null-terminated string.  */
 342         system_name[system_name_length] = '\0';
 343
 344         if (gethostname (system_name, system_name_length) == 0)
 345           break;
 346
 347         free (system_name);
 348         system_name_length *= 2;
 349       }
 350
 351     /* We always use the non-dotted host name, for simplicity.  */
 352     dot = index (system_name, '.');
 353     if (dot)
 354       *dot = '\0';
 355   }
 356
 357   {
 358     int sock_status = 0;
 359
 360     if (! socket_name)
 361       {
 362         socket_name = alloca (system_name_length + 100);
 363         sprintf (socket_name, "/tmp/emacs%d-%s/server",
 364                  (int) geteuid (), system_name);
 365       }
 366
 367     if (strlen (socket_name) < sizeof (server.sun_path))
 368       strcpy (server.sun_path, socket_name);
 369     else
 370       fprintf (stderr, "%s: socket-name %s too long",
 371                argv[0], socket_name);
 372
 373     /* See if the socket exists, and if it's owned by us. */
 374     sock_status = socket_status (server.sun_path);
 375     if (sock_status)
 376       {
 377         /* Failing that, see if LOGNAME or USER exist and differ from
 378            our euid.  If so, look for a socket based on the UID
 379            associated with the name.  This is reminiscent of the logic
 380            that init_editfns uses to set the global Vuser_full_name.  */
 381
 382         char *user_name = (char *) getenv ("LOGNAME");
 383         if (!user_name)
 384           user_name = (char *) getenv ("USER");
 385
 386         if (user_name)
 387           {
 388             struct passwd *pw = getpwnam (user_name);
 389             if (pw && (pw->pw_uid != geteuid ()))
 390               {
 391                 /* We're running under su, apparently. */
 392                 sprintf (server.sun_path, "/tmp/esrv%d-%s",
 393                          (int) pw->pw_uid, system_name);
 394                 sock_status = socket_status (server.sun_path);
 395               }
 396           }
 397       }
 398
 399      switch (sock_status)
 400        {
 401        case 1:
 402          /* There's a socket, but it isn't owned by us.  This is OK if
 403             we are root. */
 404          if (0 != geteuid ())
 405            {
 406              fprintf (stderr, "%s: Invalid socket owner\n", argv[0]);
 407              fail (argc, argv);
 408            }
 409          break;
 410
 411        case 2:
 412          /* `stat' failed */
 413          if (errno == ENOENT)
 414            fprintf (stderr,
 415                     "%s: can't find socket; have you started the server?\n\
 416 To start the server in Emacs, type \"M-x server-start\".\n",
 417                     argv[0]);
 418          else
 419            fprintf (stderr, "%s: can't stat %s: %s\n",
 420                     argv[0], server.sun_path, strerror (errno));
 421          fail (argc, argv);
 422          break;
 423        }
 424   }
 425
 426   if (connect (s, (struct sockaddr *) &server, strlen (server.sun_path) + 2)
 427       < 0)
 428     {
 429       fprintf (stderr, "%s: ", argv[0]);
 430       perror ("connect");
 431       fail (argc, argv);
 432     }
 433
 434   /* We use the stream OUT to send our command to the server.  */
 435   if ((out = fdopen (s, "r+")) == NULL)
 436     {
 437       fprintf (stderr, "%s: ", argv[0]);
 438       perror ("fdopen");
 439       fail (argc, argv);
 440     }
 441
 442   /* We use the stream IN to read the response.
 443      We used to use just one stream for both output and input
 444      on the socket, but reversing direction works nonportably:
 445      on some systems, the output appears as the first input;
 446      on other systems it does not.  */
 447   if ((in = fdopen (s, "r+")) == NULL)
 448     {
 449       fprintf (stderr, "%s: ", argv[0]);
 450       perror ("fdopen");
 451       fail (argc, argv);
 452     }
 453
 454 #ifdef HAVE_GETCWD
 455   cwd = getcwd (string, sizeof string);
 456 #else
 457   cwd = getwd (string);
 458 #endif
 459   if (cwd == 0)
 460     {
 461       /* getwd puts message in STRING if it fails.  */
 462
 463 #ifdef HAVE_GETCWD
 464       fprintf (stderr, "%s: %s (%s)\n", argv[0],
 465                "Cannot get current working directory", strerror (errno));
 466 #else
 467       fprintf (stderr, "%s: %s (%s)\n", argv[0], string, strerror (errno));
 468 #endif
 469       fail (argc, argv);
 470     }
 471
 472   if (nowait)
 473     fprintf (out, "-nowait ");
 474
 475   if (eval)
 476     fprintf (out, "-eval ");
 477
 478   if (display)
 479     fprintf (out, "-display %s ", quote_file_name (display));
 480
 481   for (i = optind; i < argc; i++)
 482     {
 483       if (eval)
 484         ; /* Don't prepend any cwd or anything like that.  */
 485       else if (*argv[i] == '+')
 486         {
 487           char *p = argv[i] + 1;
 488           while (isdigit ((unsigned char) *p) || *p == ':') p++;
 489           if (*p != 0)
 490             fprintf (out, "%s/", quote_file_name (cwd));
 491         }
 492       else if (*argv[i] != '/')
 493         fprintf (out, "%s/", quote_file_name (cwd));
 494
 495       fprintf (out, "%s ", quote_file_name (argv[i]));
 496     }
 497   fprintf (out, "\n");
 498   fflush (out);
 499
 500   /* Maybe wait for an answer.   */
 501   if (nowait)
 502     return 0;
 503
 504   if (!eval)
 505     {
 506       printf ("Waiting for Emacs...");
 507       needlf = 2;
 508     }
 509   fflush (stdout);
 510
 511   /* Now, wait for an answer and print any messages.  */
 512   while ((str = fgets (string, BUFSIZ, in)))
 513     {
 514       if (needlf == 2)
 515         printf ("\n");
 516       printf ("%s", str);
 517       needlf = str[0] == '\0' ? needlf : str[strlen (str) - 1] != '\n';
 518     }
 519
 520   if (needlf)
 521     printf ("\n");
 522   fflush (stdout);
 523
 524   return 0;
 525 }
 526
 527 #endif /* HAVE_SOCKETS */
 528 \f
 529 #ifndef HAVE_STRERROR
 530 char *
 531 strerror (errnum)
 532      int errnum;
 533 {
 534   extern char *sys_errlist[];
 535   extern int sys_nerr;
 536
 537   if (errnum >= 0 && errnum < sys_nerr)
 538     return sys_errlist[errnum];
 539   return (char *) "Unknown error";
 540 }
 541
 542 #endif /* ! HAVE_STRERROR */
 543
 544 /* arch-tag: f39bb9c4-73eb-477e-896d-50832e2ca9a7
 545    (do not change this comment) */