lib-src/emacsclient.c

   1 /* Client process that communicates with GNU Emacs acting as server.
   2    Copyright (C) 1986, 1987, 1994, 1999, 2000, 2001, 2002, 2003, 2004,
   3                  2005, 2006 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., 51 Franklin Street, Fifth Floor,
  20 Boston, MA 02110-1301, 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 #ifndef VERSION
  48 #define VERSION "unspecified"
  49 #endif
  50 \f
  51 /* Name used to invoke this program.  */
  52 char *progname;
  53
  54 /* Nonzero means don't wait for a response from Emacs.  --no-wait.  */
  55 int nowait = 0;
  56
  57 /* Nonzero means args are expressions to be evaluated.  --eval.  */
  58 int eval = 0;
  59
  60 /* The display on which Emacs should work.  --display.  */
  61 char *display = NULL;
  62
  63 /* If non-NULL, the name of an editor to fallback to if the server
  64    is not running.  --alternate-editor.   */
  65 const char * alternate_editor = NULL;
  66
  67 /* If non-NULL, the filename of the UNIX socket.  */
  68 char *socket_name = NULL;
  69
  70 void print_help_and_exit ();
  71
  72 struct option longopts[] =
  73 {
  74   { "no-wait",  no_argument,       NULL, 'n' },
  75   { "eval",     no_argument,       NULL, 'e' },
  76   { "help",     no_argument,       NULL, 'H' },
  77   { "version",  no_argument,       NULL, 'V' },
  78   { "alternate-editor", required_argument, NULL, 'a' },
  79   { "socket-name",      required_argument, NULL, 's' },
  80   { "display",  required_argument, NULL, 'd' },
  81   { 0, 0, 0, 0 }
  82 };
  83
  84 /* Decode the options from argv and argc.
  85    The global variable `optind' will say how many arguments we used up.  */
  86
  87 void
  88 decode_options (argc, argv)
  89      int argc;
  90      char **argv;
  91 {
  92   alternate_editor = getenv ("ALTERNATE_EDITOR");
  93
  94   while (1)
  95     {
  96       int opt = getopt_long (argc, argv,
  97                              "VHnea:s:d:", longopts, 0);
  98
  99       if (opt == EOF)
 100         break;
 101
 102       switch (opt)
 103         {
 104         case 0:
 105           /* If getopt returns 0, then it has already processed a
 106              long-named option.  We should do nothing.  */
 107           break;
 108
 109         case 'a':
 110           alternate_editor = optarg;
 111           break;
 112
 113         case 's':
 114           socket_name = optarg;
 115           break;
 116
 117         case 'd':
 118           display = optarg;
 119           break;
 120
 121         case 'n':
 122           nowait = 1;
 123           break;
 124
 125         case 'e':
 126           eval = 1;
 127           break;
 128
 129         case 'V':
 130           printf ("emacsclient %s\n", VERSION);
 131           exit (EXIT_SUCCESS);
 132           break;
 133
 134         case 'H':
 135           print_help_and_exit ();
 136           break;
 137
 138         default:
 139           fprintf (stderr, "Try `%s --help' for more information\n", progname);
 140           exit (EXIT_FAILURE);
 141           break;
 142         }
 143     }
 144 }
 145
 146 void
 147 print_help_and_exit ()
 148 {
 149   printf (
 150           "Usage: %s [OPTIONS] FILE...\n\
 151 Tell the Emacs server to visit the specified files.\n\
 152 Every FILE can be either just a FILENAME or [+LINE[:COLUMN]] FILENAME.\n\
 153 \n\
 154 The following OPTIONS are accepted:\n\
 155 -V, --version           Just print a version info and return\n\
 156 -H, --help              Print this usage information message\n\
 157 -n, --no-wait           Don't wait for the server to return\n\
 158 -e, --eval              Evaluate the FILE arguments as ELisp expressions\n\
 159 -d, --display=DISPLAY   Visit the file in the given display\n\
 160 -s, --socket-name=FILENAME\n\
 161                         Set the filename of the UNIX socket for communication\n\
 162 -a, --alternate-editor=EDITOR\n\
 163                         Editor to fallback to if the server is not running\n\
 164 \n\
 165 Report bugs to bug-gnu-emacs@gnu.org.\n", progname);
 166   exit (EXIT_SUCCESS);
 167 }
 168
 169 /* In NAME, insert a & before each &, each space, each newline, and
 170    any initial -.  Change spaces to underscores, too, so that the
 171    return value never contains a space.  */
 172
 173 void
 174 quote_file_name (name, stream)
 175      char *name;
 176      FILE *stream;
 177 {
 178   char *copy = (char *) malloc (strlen (name) * 2 + 1);
 179   char *p, *q;
 180
 181   p = name;
 182   q = copy;
 183   while (*p)
 184     {
 185       if (*p == ' ')
 186         {
 187           *q++ = '&';
 188           *q++ = '_';
 189           p++;
 190         }
 191       else if (*p == '\n')
 192         {
 193           *q++ = '&';
 194           *q++ = 'n';
 195           p++;
 196         }
 197       else
 198         {
 199           if (*p == '&' || (*p == '-' && p == name))
 200             *q++ = '&';
 201           *q++ = *p++;
 202         }
 203     }
 204   *q++ = 0;
 205
 206   fprintf (stream, "%s", copy);
 207
 208   free (copy);
 209 }
 210
 211 /* Like malloc but get fatal error if memory is exhausted.  */
 212
 213 long *
 214 xmalloc (size)
 215      unsigned int size;
 216 {
 217   long *result = (long *) malloc (size);
 218   if (result == NULL)
 219   {
 220     perror ("malloc");
 221     exit (EXIT_FAILURE);
 222   }
 223   return result;
 224 }
 225 \f
 226 /*
 227   Try to run a different command, or --if no alternate editor is
 228   defined-- exit with an errorcode.
 229 */
 230 void
 231 fail (argc, argv)
 232      int argc;
 233      char **argv;
 234 {
 235   if (alternate_editor)
 236     {
 237       int i = optind - 1;
 238       execvp (alternate_editor, argv + i);
 239       return;
 240     }
 241   else
 242     {
 243       exit (EXIT_FAILURE);
 244     }
 245 }
 246
 247
 248 \f
 249 #if !defined (HAVE_SOCKETS) || defined (NO_SOCKETS_IN_FILE_SYSTEM)
 250
 251 int
 252 main (argc, argv)
 253      int argc;
 254      char **argv;
 255 {
 256   fprintf (stderr, "%s: Sorry, the Emacs server is supported only\n",
 257            argv[0]);
 258   fprintf (stderr, "on systems with Berkeley sockets.\n");
 259
 260   fail (argc, argv);
 261 }
 262
 263 #else /* HAVE_SOCKETS */
 264
 265 #include <sys/types.h>
 266 #include <sys/socket.h>
 267 #include <sys/un.h>
 268 #include <sys/stat.h>
 269 #include <errno.h>
 270
 271 extern char *strerror ();
 272 extern int errno;
 273
 274 /* Three possibilities:
 275    2 - can't be `stat'ed                (sets errno)
 276    1 - isn't owned by us
 277    0 - success: none of the above */
 278
 279 static int
 280 socket_status (socket_name)
 281      char *socket_name;
 282 {
 283   struct stat statbfr;
 284
 285   if (stat (socket_name, &statbfr) == -1)
 286     return 2;
 287
 288   if (statbfr.st_uid != geteuid ())
 289     return 1;
 290
 291   return 0;
 292 }
 293
 294 int
 295 main (argc, argv)
 296      int argc;
 297      char **argv;
 298 {
 299   int s, i, needlf = 0;
 300   FILE *out, *in;
 301   struct sockaddr_un server;
 302   char *cwd, *str;
 303   char string[BUFSIZ];
 304
 305   progname = argv[0];
 306
 307   /* Process options.  */
 308   decode_options (argc, argv);
 309
 310   if ((argc - optind < 1) && !eval)
 311     {
 312       fprintf (stderr, "%s: file name or argument required\n", progname);
 313       fprintf (stderr, "Try `%s --help' for more information\n", progname);
 314       exit (EXIT_FAILURE);
 315     }
 316
 317   /*
 318    * Open up an AF_UNIX socket in this person's home directory
 319    */
 320
 321   if ((s = socket (AF_UNIX, SOCK_STREAM, 0)) < 0)
 322     {
 323       fprintf (stderr, "%s: ", argv[0]);
 324       perror ("socket");
 325       fail (argc, argv);
 326     }
 327
 328   server.sun_family = AF_UNIX;
 329
 330   {
 331     int sock_status = 0;
 332     int default_sock = !socket_name;
 333     int saved_errno;
 334     char *server_name = "server";
 335
 336     if (socket_name && !index (socket_name, '/') && !index (socket_name, '\\'))
 337       { /* socket_name is a file name component.  */
 338         server_name = socket_name;
 339         socket_name = NULL;
 340         default_sock = 1;       /* Try both UIDs.  */
 341       }
 342
 343     if (default_sock)
 344       {
 345         socket_name = alloca (100 + strlen (server_name));
 346         sprintf (socket_name, "/tmp/emacs%d/%s",
 347                  (int) geteuid (), server_name);
 348       }
 349
 350     if (strlen (socket_name) < sizeof (server.sun_path))
 351       strcpy (server.sun_path, socket_name);
 352     else
 353       {
 354         fprintf (stderr, "%s: socket-name %s too long",
 355                  argv[0], socket_name);
 356         exit (EXIT_FAILURE);
 357       }
 358
 359     /* See if the socket exists, and if it's owned by us. */
 360     sock_status = socket_status (server.sun_path);
 361     saved_errno = errno;
 362     if (sock_status && default_sock)
 363       {
 364         /* Failing that, see if LOGNAME or USER exist and differ from
 365            our euid.  If so, look for a socket based on the UID
 366            associated with the name.  This is reminiscent of the logic
 367            that init_editfns uses to set the global Vuser_full_name.  */
 368
 369         char *user_name = (char *) getenv ("LOGNAME");
 370
 371         if (!user_name)
 372           user_name = (char *) getenv ("USER");
 373
 374         if (user_name)
 375           {
 376             struct passwd *pw = getpwnam (user_name);
 377
 378             if (pw && (pw->pw_uid != geteuid ()))
 379               {
 380                 /* We're running under su, apparently. */
 381                 socket_name = alloca (100 + strlen (server_name));
 382                 sprintf (socket_name, "/tmp/emacs%d/%s",
 383                          (int) pw->pw_uid, server_name);
 384
 385                 if (strlen (socket_name) < sizeof (server.sun_path))
 386                   strcpy (server.sun_path, socket_name);
 387                 else
 388                   {
 389                     fprintf (stderr, "%s: socket-name %s too long",
 390                              argv[0], socket_name);
 391                     exit (EXIT_FAILURE);
 392                   }
 393
 394                 sock_status = socket_status (server.sun_path);
 395                 saved_errno = errno;
 396               }
 397             else
 398               errno = saved_errno;
 399           }
 400       }
 401
 402      switch (sock_status)
 403        {
 404        case 1:
 405          /* There's a socket, but it isn't owned by us.  This is OK if
 406             we are root. */
 407          if (0 != geteuid ())
 408            {
 409              fprintf (stderr, "%s: Invalid socket owner\n", argv[0]);
 410              fail (argc, argv);
 411            }
 412          break;
 413
 414        case 2:
 415          /* `stat' failed */
 416          if (saved_errno == ENOENT)
 417            fprintf (stderr,
 418                     "%s: can't find socket; have you started the server?\n\
 419 To start the server in Emacs, type \"M-x server-start\".\n",
 420                     argv[0]);
 421          else
 422            fprintf (stderr, "%s: can't stat %s: %s\n",
 423                     argv[0], server.sun_path, strerror (saved_errno));
 424          fail (argc, argv);
 425          break;
 426        }
 427   }
 428
 429   if (connect (s, (struct sockaddr *) &server, strlen (server.sun_path) + 2)
 430       < 0)
 431     {
 432       fprintf (stderr, "%s: ", argv[0]);
 433       perror ("connect");
 434       fail (argc, argv);
 435     }
 436
 437   /* We use the stream OUT to send our command to the server.  */
 438   if ((out = fdopen (s, "r+")) == NULL)
 439     {
 440       fprintf (stderr, "%s: ", argv[0]);
 441       perror ("fdopen");
 442       fail (argc, argv);
 443     }
 444
 445   /* We use the stream IN to read the response.
 446      We used to use just one stream for both output and input
 447      on the socket, but reversing direction works nonportably:
 448      on some systems, the output appears as the first input;
 449      on other systems it does not.  */
 450   if ((in = fdopen (s, "r+")) == NULL)
 451     {
 452       fprintf (stderr, "%s: ", argv[0]);
 453       perror ("fdopen");
 454       fail (argc, argv);
 455     }
 456
 457 #ifdef HAVE_GETCWD
 458   cwd = getcwd (string, sizeof string);
 459 #else
 460   cwd = getwd (string);
 461 #endif
 462   if (cwd == 0)
 463     {
 464       /* getwd puts message in STRING if it fails.  */
 465
 466 #ifdef HAVE_GETCWD
 467       fprintf (stderr, "%s: %s (%s)\n", argv[0],
 468                "Cannot get current working directory", strerror (errno));
 469 #else
 470       fprintf (stderr, "%s: %s (%s)\n", argv[0], string, strerror (errno));
 471 #endif
 472       fail (argc, argv);
 473     }
 474
 475   if (nowait)
 476     fprintf (out, "-nowait ");
 477
 478   if (eval)
 479     fprintf (out, "-eval ");
 480
 481   if (display)
 482     {
 483       fprintf (out, "-display ");
 484       quote_file_name (display, out);
 485       fprintf (out, " ");
 486     }
 487
 488   if ((argc - optind > 0))
 489     {
 490       for (i = optind; i < argc; i++)
 491         {
 492           if (eval)
 493             ; /* Don't prepend any cwd or anything like that.  */
 494           else if (*argv[i] == '+')
 495             {
 496               char *p = argv[i] + 1;
 497               while (isdigit ((unsigned char) *p) || *p == ':') p++;
 498               if (*p != 0)
 499                 {
 500                   quote_file_name (cwd, out);
 501                   fprintf (out, "/");
 502                 }
 503             }
 504           else if (*argv[i] != '/')
 505             {
 506               quote_file_name (cwd, out);
 507               fprintf (out, "/");
 508             }
 509
 510           quote_file_name (argv[i], out);
 511           fprintf (out, " ");
 512         }
 513     }
 514   else
 515     {
 516       while ((str = fgets (string, BUFSIZ, stdin)))
 517         {
 518           quote_file_name (str, out);
 519         }
 520       fprintf (out, " ");
 521     }
 522
 523   fprintf (out, "\n");
 524   fflush (out);
 525
 526   /* Maybe wait for an answer.   */
 527   if (nowait)
 528     return EXIT_SUCCESS;
 529
 530   if (!eval)
 531     {
 532       printf ("Waiting for Emacs...");
 533       needlf = 2;
 534     }
 535   fflush (stdout);
 536
 537   /* Now, wait for an answer and print any messages.  */
 538   while ((str = fgets (string, BUFSIZ, in)))
 539     {
 540       if (needlf == 2)
 541         printf ("\n");
 542       printf ("%s", str);
 543       needlf = str[0] == '\0' ? needlf : str[strlen (str) - 1] != '\n';
 544     }
 545
 546   if (needlf)
 547     printf ("\n");
 548   fflush (stdout);
 549
 550   return EXIT_SUCCESS;
 551 }
 552
 553 #endif /* HAVE_SOCKETS */
 554 \f
 555 #ifndef HAVE_STRERROR
 556 char *
 557 strerror (errnum)
 558      int errnum;
 559 {
 560   extern char *sys_errlist[];
 561   extern int sys_nerr;
 562
 563   if (errnum >= 0 && errnum < sys_nerr)
 564     return sys_errlist[errnum];
 565   return (char *) "Unknown error";
 566 }
 567
 568 #endif /* ! HAVE_STRERROR */
 569
 570 /* arch-tag: f39bb9c4-73eb-477e-896d-50832e2ca9a7
 571    (do not change this comment) */
 572
 573 /* emacsclient.c ends here */