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, 2004
   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, the filename 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   alternate_editor = getenv ("ALTERNATE_EDITOR");
  96
  97   while (1)
  98     {
  99       int opt = getopt_long (argc, argv,
 100                              "VHnea:s:d:", longopts, 0);
 101
 102       if (opt == EOF)
 103         break;
 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 /* In NAME, insert a & before each &, each space, each newline, and
 173    any initial -.  Change spaces to underscores, too, so that the
 174    return value never contains a space.  */
 175
 176 void
 177 quote_file_name (name, stream)
 178      char *name;
 179      FILE *stream;
 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   fprintf (stream, copy);
 210
 211   free (copy);
 212 }
 213
 214 /* Like malloc but get fatal error if memory is exhausted.  */
 215
 216 long *
 217 xmalloc (size)
 218      unsigned int size;
 219 {
 220   long *result = (long *) malloc (size);
 221   if (result == NULL)
 222   {
 223     perror ("malloc");
 224     exit (1);
 225   }
 226   return result;
 227 }
 228 \f
 229 /*
 230   Try to run a different command, or --if no alternate editor is
 231   defined-- exit with an errorcode.
 232 */
 233 void
 234 fail (argc, argv)
 235      int argc;
 236      char **argv;
 237 {
 238   if (alternate_editor)
 239     {
 240       int i = optind - 1;
 241       execvp (alternate_editor, argv + i);
 242       return;
 243     }
 244   else
 245     {
 246       exit (1);
 247     }
 248 }
 249
 250
 251 \f
 252 #if !defined (HAVE_SOCKETS) || defined (NO_SOCKETS_IN_FILE_SYSTEM)
 253
 254 int
 255 main (argc, argv)
 256      int argc;
 257      char **argv;
 258 {
 259   fprintf (stderr, "%s: Sorry, the Emacs server is supported only\n",
 260            argv[0]);
 261   fprintf (stderr, "on systems with Berkeley sockets.\n");
 262
 263   fail (argc, argv);
 264 }
 265
 266 #else /* HAVE_SOCKETS */
 267
 268 #include <sys/types.h>
 269 #include <sys/socket.h>
 270 #include <sys/un.h>
 271 #include <sys/stat.h>
 272 #include <errno.h>
 273
 274 extern char *strerror ();
 275 extern int errno;
 276
 277 /* Three possibilities:
 278    2 - can't be `stat'ed                (sets errno)
 279    1 - isn't owned by us
 280    0 - success: none of the above */
 281
 282 static int
 283 socket_status (socket_name)
 284      char *socket_name;
 285 {
 286   struct stat statbfr;
 287
 288   if (stat (socket_name, &statbfr) == -1)
 289     return 2;
 290
 291   if (statbfr.st_uid != geteuid ())
 292     return 1;
 293
 294   return 0;
 295 }
 296
 297 int
 298 main (argc, argv)
 299      int argc;
 300      char **argv;
 301 {
 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) && !eval)
 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     int sock_status = 0;
 335     int default_sock = !socket_name;
 336     int saved_errno;
 337     char *server_name = "server";
 338
 339     if (socket_name && !index (socket_name, '/') && !index (socket_name, '\\'))
 340       { /* socket_name is a file name component.  */
 341         server_name = socket_name;
 342         socket_name = NULL;
 343         default_sock = 1;       /* Try both UIDs.  */
 344       }
 345
 346     if (default_sock)
 347       {
 348         socket_name = alloca (100 + strlen (server_name));
 349         sprintf (socket_name, "/tmp/emacs%d/%s",
 350                  (int) geteuid (), server_name);
 351       }
 352
 353     if (strlen (socket_name) < sizeof (server.sun_path))
 354       strcpy (server.sun_path, socket_name);
 355     else
 356       {
 357         fprintf (stderr, "%s: socket-name %s too long",
 358                  argv[0], socket_name);
 359         exit (1);
 360       }
 361
 362     /* See if the socket exists, and if it's owned by us. */
 363     sock_status = socket_status (server.sun_path);
 364     saved_errno = errno;
 365     if (sock_status && default_sock)
 366       {
 367         /* Failing that, see if LOGNAME or USER exist and differ from
 368            our euid.  If so, look for a socket based on the UID
 369            associated with the name.  This is reminiscent of the logic
 370            that init_editfns uses to set the global Vuser_full_name.  */
 371
 372         char *user_name = (char *) getenv ("LOGNAME");
 373
 374         if (!user_name)
 375           user_name = (char *) getenv ("USER");
 376
 377         if (user_name)
 378           {
 379             struct passwd *pw = getpwnam (user_name);
 380
 381             if (pw && (pw->pw_uid != geteuid ()))
 382               {
 383                 /* We're running under su, apparently. */
 384                 socket_name = alloca (100 + strlen (server_name));
 385                 sprintf (socket_name, "/tmp/emacs%d/%s",
 386                          (int) pw->pw_uid, server_name);
 387
 388                 if (strlen (socket_name) < sizeof (server.sun_path))
 389                   strcpy (server.sun_path, socket_name);
 390                 else
 391                   {
 392                     fprintf (stderr, "%s: socket-name %s too long",
 393                              argv[0], socket_name);
 394                     exit (1);
 395                   }
 396
 397                 sock_status = socket_status (server.sun_path);
 398                 saved_errno = errno;
 399               }
 400             else
 401               errno = saved_errno;
 402           }
 403       }
 404
 405      switch (sock_status)
 406        {
 407        case 1:
 408          /* There's a socket, but it isn't owned by us.  This is OK if
 409             we are root. */
 410          if (0 != geteuid ())
 411            {
 412              fprintf (stderr, "%s: Invalid socket owner\n", argv[0]);
 413              fail (argc, argv);
 414            }
 415          break;
 416
 417        case 2:
 418          /* `stat' failed */
 419          if (saved_errno == ENOENT)
 420            fprintf (stderr,
 421                     "%s: can't find socket; have you started the server?\n\
 422 To start the server in Emacs, type \"M-x server-start\".\n",
 423                     argv[0]);
 424          else
 425            fprintf (stderr, "%s: can't stat %s: %s\n",
 426                     argv[0], server.sun_path, strerror (saved_errno));
 427          fail (argc, argv);
 428          break;
 429        }
 430   }
 431
 432   if (connect (s, (struct sockaddr *) &server, strlen (server.sun_path) + 2)
 433       < 0)
 434     {
 435       fprintf (stderr, "%s: ", argv[0]);
 436       perror ("connect");
 437       fail (argc, argv);
 438     }
 439
 440   /* We use the stream OUT to send our command to the server.  */
 441   if ((out = fdopen (s, "r+")) == NULL)
 442     {
 443       fprintf (stderr, "%s: ", argv[0]);
 444       perror ("fdopen");
 445       fail (argc, argv);
 446     }
 447
 448   /* We use the stream IN to read the response.
 449      We used to use just one stream for both output and input
 450      on the socket, but reversing direction works nonportably:
 451      on some systems, the output appears as the first input;
 452      on other systems it does not.  */
 453   if ((in = fdopen (s, "r+")) == NULL)
 454     {
 455       fprintf (stderr, "%s: ", argv[0]);
 456       perror ("fdopen");
 457       fail (argc, argv);
 458     }
 459
 460 #ifdef HAVE_GETCWD
 461   cwd = getcwd (string, sizeof string);
 462 #else
 463   cwd = getwd (string);
 464 #endif
 465   if (cwd == 0)
 466     {
 467       /* getwd puts message in STRING if it fails.  */
 468
 469 #ifdef HAVE_GETCWD
 470       fprintf (stderr, "%s: %s (%s)\n", argv[0],
 471                "Cannot get current working directory", strerror (errno));
 472 #else
 473       fprintf (stderr, "%s: %s (%s)\n", argv[0], string, strerror (errno));
 474 #endif
 475       fail (argc, argv);
 476     }
 477
 478   if (nowait)
 479     fprintf (out, "-nowait ");
 480
 481   if (eval)
 482     fprintf (out, "-eval ");
 483
 484   if (display)
 485     {
 486       fprintf (out, "-display ");
 487       quote_file_name (display, out);
 488       fprintf (out, " ");
 489     }
 490
 491   if ((argc - optind > 0))
 492     {
 493       for (i = optind; i < argc; i++)
 494         {
 495           if (eval)
 496             ; /* Don't prepend any cwd or anything like that.  */
 497           else if (*argv[i] == '+')
 498             {
 499               char *p = argv[i] + 1;
 500               while (isdigit ((unsigned char) *p) || *p == ':') p++;
 501               if (*p != 0)
 502                 {
 503                   quote_file_name (cwd, out);
 504                   fprintf (out, "/");
 505                 }
 506             }
 507           else if (*argv[i] != '/')
 508             {
 509               quote_file_name (cwd, out);
 510               fprintf (out, "/");
 511             }
 512
 513           quote_file_name (argv[i], out);
 514           fprintf (out, " ");
 515         }
 516     }
 517   else
 518     {
 519       while ((str = fgets (string, BUFSIZ, stdin)))
 520         {
 521           quote_file_name (str, out);
 522         }
 523       fprintf (out, " ");
 524     }
 525
 526   fprintf (out, "\n");
 527   fflush (out);
 528
 529   /* Maybe wait for an answer.   */
 530   if (nowait)
 531     return 0;
 532
 533   if (!eval)
 534     {
 535       printf ("Waiting for Emacs...");
 536       needlf = 2;
 537     }
 538   fflush (stdout);
 539
 540   /* Now, wait for an answer and print any messages.  */
 541   while ((str = fgets (string, BUFSIZ, in)))
 542     {
 543       if (needlf == 2)
 544         printf ("\n");
 545       printf ("%s", str);
 546       needlf = str[0] == '\0' ? needlf : str[strlen (str) - 1] != '\n';
 547     }
 548
 549   if (needlf)
 550     printf ("\n");
 551   fflush (stdout);
 552
 553   return 0;
 554 }
 555
 556 #endif /* HAVE_SOCKETS */
 557 \f
 558 #ifndef HAVE_STRERROR
 559 char *
 560 strerror (errnum)
 561      int errnum;
 562 {
 563   extern char *sys_errlist[];
 564   extern int sys_nerr;
 565
 566   if (errnum >= 0 && errnum < sys_nerr)
 567     return sys_errlist[errnum];
 568   return (char *) "Unknown error";
 569 }
 570
 571 #endif /* ! HAVE_STRERROR */
 572
 573 /* arch-tag: f39bb9c4-73eb-477e-896d-50832e2ca9a7
 574    (do not change this comment) */