lib-src/emacsclient.c

   1 /* Client process that communicates with GNU Emacs acting as server.
   2    Copyright (C) 1986, 1987, 1994, 1999, 2000, 2001
   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 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   { "display",  required_argument, NULL, 'd' },
  80   { 0, 0, 0, 0 }
  81 };
  82
  83 /* Decode the options from argv and argc.
  84    The global variable `optind' will say how many arguments we used up.  */
  85
  86 void
  87 decode_options (argc, argv)
  88      int argc;
  89      char **argv;
  90 {
  91   while (1)
  92     {
  93       int opt = getopt_long (argc, argv,
  94                              "VHnea:d:", longopts, 0);
  95
  96       if (opt == EOF)
  97         break;
  98
  99       alternate_editor = getenv ("ALTERNATE_EDITOR");
 100
 101       switch (opt)
 102         {
 103         case 0:
 104           /* If getopt returns 0, then it has already processed a
 105              long-named option.  We should do nothing.  */
 106           break;
 107
 108         case 'a':
 109           alternate_editor = optarg;
 110           break;
 111
 112         case 'd':
 113           display = optarg;
 114           break;
 115
 116         case 'n':
 117           nowait = 1;
 118           break;
 119
 120         case 'e':
 121           eval = 1;
 122           break;
 123
 124         case 'V':
 125           fprintf (stderr, "emacsclient %s\n", VERSION);
 126           exit (1);
 127           break;
 128
 129         case 'H':
 130         default:
 131           print_help_and_exit ();
 132         }
 133     }
 134 }
 135
 136 void
 137 print_help_and_exit ()
 138 {
 139   fprintf (stderr,
 140            "Usage: %s [OPTIONS] FILE...\n\
 141 Tell the Emacs server to visit the specified files.\n\
 142 Every FILE can be either just a FILENAME or [+LINE[:COLUMN]] FILENAME.\n\
 143 The following OPTIONS are accepted:\n\
 144 -V, --version           Just print a version info and return\n\
 145 -H, --help              Print this usage information message\n\
 146 -n, --no-wait           Don't wait for the server to return\n\
 147 -e, --eval              Evaluate the FILE arguments as ELisp expressions\n\
 148 -d, --display=DISPLAY   Visit the file in the given display\n\
 149 -a, --alternate-editor=EDITOR\n\
 150                         Editor to fallback to if the server is not running\n\
 151 Report bugs to bug-gnu-emacs@gnu.org.\n", progname);
 152   exit (1);
 153 }
 154
 155 /* Return a copy of NAME, inserting a &
 156    before each &, each space, each newline, and any initial -.
 157    Change spaces to underscores, too, so that the
 158    return value never contains a space.  */
 159
 160 char *
 161 quote_file_name (name)
 162      char *name;
 163 {
 164   char *copy = (char *) malloc (strlen (name) * 2 + 1);
 165   char *p, *q;
 166
 167   p = name;
 168   q = copy;
 169   while (*p)
 170     {
 171       if (*p == ' ')
 172         {
 173           *q++ = '&';
 174           *q++ = '_';
 175           p++;
 176         }
 177       else if (*p == '\n')
 178         {
 179           *q++ = '&';
 180           *q++ = 'n';
 181           p++;
 182         }
 183       else
 184         {
 185           if (*p == '&' || (*p == '-' && p == name))
 186             *q++ = '&';
 187           *q++ = *p++;
 188         }
 189     }
 190   *q++ = 0;
 191
 192   return copy;
 193 }
 194
 195 /* Like malloc but get fatal error if memory is exhausted.  */
 196
 197 long *
 198 xmalloc (size)
 199      unsigned int size;
 200 {
 201   long *result = (long *) malloc (size);
 202   if (result == NULL)
 203   {
 204     perror ("malloc");
 205     exit (1);
 206   }
 207   return result;
 208 }
 209 \f
 210 /*
 211   Try to run a different command, or --if no alternate editor is
 212   defined-- exit with an errorcode.
 213 */
 214 void
 215 fail (argc, argv)
 216      int argc;
 217      char **argv;
 218 {
 219   if (alternate_editor)
 220     {
 221       int i = optind - 1;
 222       execvp (alternate_editor, argv + i);
 223       return;
 224     }
 225   else
 226     {
 227       exit (1);
 228     }
 229 }
 230
 231
 232 \f
 233 #if !defined (HAVE_SOCKETS) || defined (NO_SOCKETS_IN_FILE_SYSTEM)
 234
 235 int
 236 main (argc, argv)
 237      int argc;
 238      char **argv;
 239 {
 240   fprintf (stderr, "%s: Sorry, the Emacs server is supported only\n",
 241            argv[0]);
 242   fprintf (stderr, "on systems with Berkeley sockets.\n");
 243
 244   fail (argc, argv);
 245 }
 246
 247 #else /* HAVE_SOCKETS */
 248
 249 #include <sys/types.h>
 250 #include <sys/socket.h>
 251 #include <sys/un.h>
 252 #include <sys/stat.h>
 253 #include <errno.h>
 254
 255 extern char *strerror ();
 256 extern int errno;
 257
 258 /* Three possibilities:
 259    2 - can't be `stat'ed                (sets errno)
 260    1 - isn't owned by us
 261    0 - success: none of the above */
 262
 263 static int
 264 socket_status (socket_name)
 265      char *socket_name;
 266 {
 267   struct stat statbfr;
 268
 269   if (stat (socket_name, &statbfr) == -1)
 270     return 2;
 271
 272   if (statbfr.st_uid != geteuid ())
 273     return 1;
 274
 275   return 0;
 276 }
 277
 278 int
 279 main (argc, argv)
 280      int argc;
 281      char **argv;
 282 {
 283   char *system_name;
 284   int system_name_length;
 285   int s, i, needlf = 0;
 286   FILE *out, *in;
 287   struct sockaddr_un server;
 288   char *cwd, *str;
 289   char string[BUFSIZ];
 290
 291   progname = argv[0];
 292
 293   /* Process options.  */
 294   decode_options (argc, argv);
 295
 296   if (argc - optind < 1)
 297     print_help_and_exit ();
 298
 299   /*
 300    * Open up an AF_UNIX socket in this person's home directory
 301    */
 302
 303   if ((s = socket (AF_UNIX, SOCK_STREAM, 0)) < 0)
 304     {
 305       fprintf (stderr, "%s: ", argv[0]);
 306       perror ("socket");
 307       fail (argc, argv);
 308     }
 309
 310   server.sun_family = AF_UNIX;
 311
 312   {
 313     char *dot;
 314     system_name_length = 32;
 315
 316     while (1)
 317       {
 318         system_name = (char *) xmalloc (system_name_length + 1);
 319
 320         /* system_name must be null-terminated string.  */
 321         system_name[system_name_length] = '\0';
 322
 323         if (gethostname (system_name, system_name_length) == 0)
 324           break;
 325
 326         free (system_name);
 327         system_name_length *= 2;
 328       }
 329
 330     /* We always use the non-dotted host name, for simplicity.  */
 331     dot = index (system_name, '.');
 332     if (dot)
 333       *dot = '\0';
 334   }
 335
 336   {
 337     int sock_status = 0;
 338
 339     sprintf (server.sun_path, "/tmp/esrv%d-%s", (int) geteuid (), system_name);
 340
 341     /* See if the socket exists, and if it's owned by us. */
 342     sock_status = socket_status (server.sun_path);
 343     if (sock_status)
 344       {
 345         /* Failing that, see if LOGNAME or USER exist and differ from
 346            our euid.  If so, look for a socket based on the UID
 347            associated with the name.  This is reminiscent of the logic
 348            that init_editfns uses to set the global Vuser_full_name.  */
 349
 350         char *user_name = (char *) getenv ("LOGNAME");
 351         if (!user_name)
 352           user_name = (char *) getenv ("USER");
 353
 354         if (user_name)
 355           {
 356             struct passwd *pw = getpwnam (user_name);
 357             if (pw && (pw->pw_uid != geteuid ()))
 358               {
 359                 /* We're running under su, apparently. */
 360                 sprintf (server.sun_path, "/tmp/esrv%d-%s",
 361                          (int) pw->pw_uid, system_name);
 362                 sock_status = socket_status (server.sun_path);
 363               }
 364           }
 365       }
 366
 367      switch (sock_status)
 368        {
 369        case 1:
 370          /* There's a socket, but it isn't owned by us.  This is OK if
 371             we are root. */
 372          if (0 != geteuid ())
 373            {
 374              fprintf (stderr, "%s: Invalid socket owner\n", argv[0]);
 375              fail (argc, argv);
 376            }
 377          break;
 378
 379        case 2:
 380          /* `stat' failed */
 381          if (errno == ENOENT)
 382            fprintf (stderr,
 383                     "%s: can't find socket; have you started the server?\n\
 384 To start the server in Emacs, type \"M-x server-start\".\n",
 385                     argv[0]);
 386          else
 387            fprintf (stderr, "%s: can't stat %s: %s\n",
 388                     argv[0], server.sun_path, strerror (errno));
 389          fail (argc, argv);
 390          break;
 391        }
 392   }
 393
 394   if (connect (s, (struct sockaddr *) &server, strlen (server.sun_path) + 2)
 395       < 0)
 396     {
 397       fprintf (stderr, "%s: ", argv[0]);
 398       perror ("connect");
 399       fail (argc, argv);
 400     }
 401
 402   /* We use the stream OUT to send our command to the server.  */
 403   if ((out = fdopen (s, "r+")) == NULL)
 404     {
 405       fprintf (stderr, "%s: ", argv[0]);
 406       perror ("fdopen");
 407       fail (argc, argv);
 408     }
 409
 410   /* We use the stream IN to read the response.
 411      We used to use just one stream for both output and input
 412      on the socket, but reversing direction works nonportably:
 413      on some systems, the output appears as the first input;
 414      on other systems it does not.  */
 415   if ((in = fdopen (s, "r+")) == NULL)
 416     {
 417       fprintf (stderr, "%s: ", argv[0]);
 418       perror ("fdopen");
 419       fail (argc, argv);
 420     }
 421
 422 #ifdef HAVE_GETCWD
 423   cwd = getcwd (string, sizeof string);
 424 #else
 425   cwd = getwd (string);
 426 #endif
 427   if (cwd == 0)
 428     {
 429       /* getwd puts message in STRING if it fails.  */
 430       fprintf (stderr, "%s: %s (%s)\n", argv[0],
 431 #ifdef HAVE_GETCWD
 432                "Cannot get current working directory",
 433 #else
 434                string,
 435 #endif
 436                strerror (errno));
 437       fail (argc, argv);
 438     }
 439
 440   if (nowait)
 441     fprintf (out, "-nowait ");
 442
 443   if (eval)
 444     fprintf (out, "-eval ");
 445
 446   if (display)
 447     fprintf (out, "-display %s ", quote_file_name (display));
 448
 449   for (i = optind; i < argc; i++)
 450     {
 451       if (eval)
 452         ; /* Don't prepend any cwd or anything like that.  */
 453       else if (*argv[i] == '+')
 454         {
 455           char *p = argv[i] + 1;
 456           while (isdigit ((unsigned char) *p) || *p == ':') p++;
 457           if (*p != 0)
 458             fprintf (out, "%s/", quote_file_name (cwd));
 459         }
 460       else if (*argv[i] != '/')
 461         fprintf (out, "%s/", quote_file_name (cwd));
 462
 463       fprintf (out, "%s ", quote_file_name (argv[i]));
 464     }
 465   fprintf (out, "\n");
 466   fflush (out);
 467
 468   /* Maybe wait for an answer.   */
 469   if (nowait)
 470     return 0;
 471
 472   if (!eval)
 473     {
 474       printf ("Waiting for Emacs...");
 475       needlf = 2;
 476     }
 477   fflush (stdout);
 478
 479   /* Now, wait for an answer and print any messages.  */
 480   while ((str = fgets (string, BUFSIZ, in)))
 481     {
 482       if (needlf == 2)
 483         printf ("\n");
 484       printf ("%s", str);
 485       needlf = str[0] == '\0' ? needlf : str[strlen (str) - 1] != '\n';
 486     }
 487
 488   if (needlf)
 489     printf ("\n");
 490   fflush (stdout);
 491
 492   return 0;
 493 }
 494
 495 #endif /* HAVE_SOCKETS */
 496 \f
 497 #ifndef HAVE_STRERROR
 498 char *
 499 strerror (errnum)
 500      int errnum;
 501 {
 502   extern char *sys_errlist[];
 503   extern int sys_nerr;
 504
 505   if (errnum >= 0 && errnum < sys_nerr)
 506     return sys_errlist[errnum];
 507   return (char *) "Unknown error";
 508 }
 509
 510 #endif /* ! HAVE_STRERROR */