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, 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   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 /* 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 void
 178 quote_file_name (name, stream)
 179      char *name;
 180      FILE *stream;
 181 {
 182   char *copy = (char *) malloc (strlen (name) * 2 + 1);
 183   char *p, *q;
 184
 185   p = name;
 186   q = copy;
 187   while (*p)
 188     {
 189       if (*p == ' ')
 190         {
 191           *q++ = '&';
 192           *q++ = '_';
 193           p++;
 194         }
 195       else if (*p == '\n')
 196         {
 197           *q++ = '&';
 198           *q++ = 'n';
 199           p++;
 200         }
 201       else
 202         {
 203           if (*p == '&' || (*p == '-' && p == name))
 204             *q++ = '&';
 205           *q++ = *p++;
 206         }
 207     }
 208   *q++ = 0;
 209
 210   fprintf (stream, copy);
 211
 212   free (copy);
 213 }
 214
 215 /* Like malloc but get fatal error if memory is exhausted.  */
 216
 217 long *
 218 xmalloc (size)
 219      unsigned int size;
 220 {
 221   long *result = (long *) malloc (size);
 222   if (result == NULL)
 223   {
 224     perror ("malloc");
 225     exit (1);
 226   }
 227   return result;
 228 }
 229 \f
 230 /*
 231   Try to run a different command, or --if no alternate editor is
 232   defined-- exit with an errorcode.
 233 */
 234 void
 235 fail (argc, argv)
 236      int argc;
 237      char **argv;
 238 {
 239   if (alternate_editor)
 240     {
 241       int i = optind - 1;
 242       execvp (alternate_editor, argv + i);
 243       return;
 244     }
 245   else
 246     {
 247       exit (1);
 248     }
 249 }
 250
 251
 252 \f
 253 #if !defined (HAVE_SOCKETS) || defined (NO_SOCKETS_IN_FILE_SYSTEM)
 254
 255 int
 256 main (argc, argv)
 257      int argc;
 258      char **argv;
 259 {
 260   fprintf (stderr, "%s: Sorry, the Emacs server is supported only\n",
 261            argv[0]);
 262   fprintf (stderr, "on systems with Berkeley sockets.\n");
 263
 264   fail (argc, argv);
 265 }
 266
 267 #else /* HAVE_SOCKETS */
 268
 269 #include <sys/types.h>
 270 #include <sys/socket.h>
 271 #include <sys/un.h>
 272 #include <sys/stat.h>
 273 #include <errno.h>
 274
 275 extern char *strerror ();
 276 extern int errno;
 277
 278 /* Three possibilities:
 279    2 - can't be `stat'ed                (sets errno)
 280    1 - isn't owned by us
 281    0 - success: none of the above */
 282
 283 static int
 284 socket_status (socket_name)
 285      char *socket_name;
 286 {
 287   struct stat statbfr;
 288
 289   if (stat (socket_name, &statbfr) == -1)
 290     return 2;
 291
 292   if (statbfr.st_uid != geteuid ())
 293     return 1;
 294
 295   return 0;
 296 }
 297
 298 int
 299 main (argc, argv)
 300      int argc;
 301      char **argv;
 302 {
 303   char *system_name;
 304   int system_name_length;
 305   int s, i, needlf = 0;
 306   FILE *out, *in;
 307   struct sockaddr_un server;
 308   char *cwd, *str;
 309   char string[BUFSIZ];
 310
 311   progname = argv[0];
 312
 313   /* Process options.  */
 314   decode_options (argc, argv);
 315
 316   if ((argc - optind < 1) && !eval)
 317     {
 318       fprintf (stderr, "%s: file name or argument required\n", progname);
 319       fprintf (stderr, "Try `%s --help' for more information\n", progname);
 320       exit (1);
 321     }
 322
 323   /*
 324    * Open up an AF_UNIX socket in this person's home directory
 325    */
 326
 327   if ((s = socket (AF_UNIX, SOCK_STREAM, 0)) < 0)
 328     {
 329       fprintf (stderr, "%s: ", argv[0]);
 330       perror ("socket");
 331       fail (argc, argv);
 332     }
 333
 334   server.sun_family = AF_UNIX;
 335
 336   {
 337     char *dot;
 338     system_name_length = 32;
 339
 340     while (1)
 341       {
 342         system_name = (char *) xmalloc (system_name_length + 1);
 343
 344         /* system_name must be null-terminated string.  */
 345         system_name[system_name_length] = '\0';
 346
 347         if (gethostname (system_name, system_name_length) == 0)
 348           break;
 349
 350         free (system_name);
 351         system_name_length *= 2;
 352       }
 353
 354     /* We always use the non-dotted host name, for simplicity.  */
 355     dot = index (system_name, '.');
 356     if (dot)
 357       *dot = '\0';
 358   }
 359
 360   {
 361     int sock_status = 0;
 362
 363     if (! socket_name)
 364       {
 365         socket_name = alloca (system_name_length + 100);
 366         sprintf (socket_name, "/tmp/emacs%d-%s/server",
 367                  (int) geteuid (), system_name);
 368       }
 369
 370     if (strlen (socket_name) < sizeof (server.sun_path))
 371       strcpy (server.sun_path, socket_name);
 372     else
 373       fprintf (stderr, "%s: socket-name %s too long",
 374                argv[0], socket_name);
 375
 376     /* See if the socket exists, and if it's owned by us. */
 377     sock_status = socket_status (server.sun_path);
 378     if (sock_status)
 379       {
 380         /* Failing that, see if LOGNAME or USER exist and differ from
 381            our euid.  If so, look for a socket based on the UID
 382            associated with the name.  This is reminiscent of the logic
 383            that init_editfns uses to set the global Vuser_full_name.  */
 384
 385         char *user_name = (char *) getenv ("LOGNAME");
 386         if (!user_name)
 387           user_name = (char *) getenv ("USER");
 388
 389         if (user_name)
 390           {
 391             struct passwd *pw = getpwnam (user_name);
 392             if (pw && (pw->pw_uid != geteuid ()))
 393               {
 394                 /* We're running under su, apparently. */
 395                 sprintf (server.sun_path, "/tmp/esrv%d-%s",
 396                          (int) pw->pw_uid, system_name);
 397                 sock_status = socket_status (server.sun_path);
 398               }
 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 (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 (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 0;
 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 0;
 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) */