lib-src/emacsserver.c

   1 /* Communication subprocess for GNU Emacs acting as server.
   2    Copyright (C) 1986, 1987, 1992, 1994 Free Software Foundation, Inc.
   3
   4 This file is part of GNU Emacs.
   5
   6 GNU Emacs is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Emacs is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Emacs; see the file COPYING.  If not, write to
  18 the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  19 Boston, MA 02111-1307, USA.  */
  20
  21
  22 /* The GNU Emacs edit server process is run as a subprocess of Emacs
  23    under control of the file lisp/server.el.
  24    This program accepts communication from client (program emacsclient.c)
  25    and passes their commands (consisting of keyboard characters)
  26    up to the Emacs which then executes them.  */
  27
  28 #define NO_SHORTNAMES
  29 #include <signal.h>
  30 #include <../src/config.h>
  31 #undef read
  32 #undef write
  33 #undef open
  34 #undef close
  35 #undef signal
  36
  37 #if !defined (HAVE_SOCKETS) && !defined (HAVE_SYSVIPC)
  38 #include <stdio.h>
  39
  40 main ()
  41 {
  42   fprintf (stderr, "Sorry, the Emacs server is supported only on systems\n");
  43   fprintf (stderr, "with Berkeley sockets or System V IPC.\n");
  44   exit (1);
  45 }
  46
  47 #else /* HAVE_SOCKETS or HAVE_SYSVIPC */
  48
  49 #if defined (HAVE_SOCKETS) && ! defined (NO_SOCKETS_IN_FILE_SYSTEM)
  50 /* BSD code is very different from SYSV IPC code */
  51
  52 #include <sys/types.h>
  53 #include <sys/file.h>
  54 #include <sys/socket.h>
  55 #include <sys/un.h>
  56 #include <stdio.h>
  57 #include <errno.h>
  58 #include <sys/stat.h>
  59
  60 extern int errno;
  61
  62 /* Copied from src/process.c */
  63 #ifdef FD_SET
  64 /* We could get this from param.h, but better not to depend on finding that.
  65    And better not to risk that it might define other symbols used in this
  66    file.  */
  67 #ifdef FD_SETSIZE
  68 #define MAXDESC FD_SETSIZE
  69 #else
  70 #define MAXDESC 64
  71 #endif
  72 #define SELECT_TYPE fd_set
  73 #else /* no FD_SET */
  74 #define MAXDESC 32
  75 #define SELECT_TYPE int
  76
  77 /* Define the macros to access a single-int bitmap of descriptors.  */
  78 #define FD_SET(n, p) (*(p) |= (1 << (n)))
  79 #define FD_CLR(n, p) (*(p) &= ~(1 << (n)))
  80 #define FD_ISSET(n, p) (*(p) & (1 << (n)))
  81 #define FD_ZERO(p) (*(p) = 0)
  82 #endif /* no FD_SET */
  83
  84 /* This is the file name of the socket that we made.  */
  85
  86 char *socket_name;
  87
  88 /* Name of this program.  */
  89
  90 char *progname;
  91 \f
  92 /* Handle fatal signals.  */
  93
  94 /* This is the handler.  */
  95
  96 SIGTYPE
  97 delete_socket (sig)
  98      int sig;
  99 {
 100   signal (sig, SIG_DFL);
 101   unlink (socket_name);
 102   kill (getpid (), sig);
 103 }
 104
 105 /* Set up to handle all the signals.  */
 106
 107 handle_signals ()
 108 {
 109   signal (SIGHUP, delete_socket);
 110   signal (SIGINT, delete_socket);
 111   signal (SIGQUIT, delete_socket);
 112   signal (SIGILL, delete_socket);
 113   signal (SIGTRAP, delete_socket);
 114 #ifdef SIGABRT
 115   signal (SIGABRT, delete_socket);
 116 #endif
 117 #ifdef SIGHWE
 118   signal (SIGHWE, delete_socket);
 119 #endif
 120 #ifdef SIGPRE
 121   signal (SIGPRE, delete_socket);
 122 #endif
 123 #ifdef SIGORE
 124   signal (SIGORE, delete_socket);
 125 #endif
 126 #ifdef SIGUME
 127   signal (SIGUME, delete_socket);
 128 #endif
 129 #ifdef SIGDLK
 130   signal (SIGDLK, delete_socket);
 131 #endif
 132 #ifdef SIGCPULIM
 133   signal (SIGCPULIM, delete_socket);
 134 #endif
 135 #ifdef SIGIOT
 136   /* This is missing on some systems - OS/2, for example.  */
 137   signal (SIGIOT, delete_socket);
 138 #endif
 139 #ifdef SIGEMT
 140   signal (SIGEMT, delete_socket);
 141 #endif
 142   signal (SIGFPE, delete_socket);
 143 #ifdef SIGBUS
 144   signal (SIGBUS, delete_socket);
 145 #endif
 146   signal (SIGSEGV, delete_socket);
 147 #ifdef SIGSYS
 148   signal (SIGSYS, delete_socket);
 149 #endif
 150   signal (SIGTERM, delete_socket);
 151 #ifdef SIGXCPU
 152   signal (SIGXCPU, delete_socket);
 153 #endif
 154 #ifdef SIGXFSZ
 155   signal (SIGXFSZ, delete_socket);
 156 #endif /* SIGXFSZ */
 157
 158 #ifdef AIX
 159 /* 20 is SIGCHLD, 21 is SIGTTIN, 22 is SIGTTOU.  */
 160   signal (SIGXCPU, delete_socket);
 161 #ifndef _I386
 162   signal (SIGIOINT, delete_socket);
 163 #endif
 164   signal (SIGGRANT, delete_socket);
 165   signal (SIGRETRACT, delete_socket);
 166   signal (SIGSOUND, delete_socket);
 167   signal (SIGMSG, delete_socket);
 168 #endif /* AIX */
 169 }
 170 \f
 171 /* Print error message.  `s1' is printf control string, `s2' is arg for it. */
 172 void
 173 error (s1, s2)
 174      char *s1, *s2;
 175 {
 176   fprintf (stderr, "%s: ", progname);
 177   fprintf (stderr, s1, s2);
 178   fprintf (stderr, "\n");
 179 }
 180
 181 /* Print error message and exit.  */
 182 void
 183 fatal (s1, s2)
 184      char *s1, *s2;
 185 {
 186   error (s1, s2);
 187   exit (1);
 188 }
 189
 190 /* Like malloc but get fatal error if memory is exhausted.  */
 191
 192 long *
 193 xmalloc (size)
 194      unsigned int size;
 195 {
 196   long *result = (long *) malloc (size);
 197   if (result == NULL)
 198     fatal ("virtual memory exhausted", 0);
 199   return result;
 200 }
 201 \f
 202 int
 203 main (argc, argv)
 204      int argc;
 205      char **argv;
 206 {
 207   char system_name[32];
 208   int s, infd;
 209 #ifdef SOCKLEN_TYPE
 210   SOCKLEN_TYPE fromlen;
 211 #else
 212   size_t fromlen;
 213 #endif
 214   struct sockaddr_un server, fromunix;
 215   char *homedir;
 216   char *str, string[BUFSIZ], code[BUFSIZ];
 217   FILE *infile;
 218   FILE **openfiles;
 219   int openfiles_size;
 220   struct stat statbuf;
 221
 222 #ifndef convex
 223   char *getenv ();
 224 #endif
 225
 226   progname = argv[0];
 227
 228   openfiles_size = 20;
 229   openfiles = (FILE **) malloc (openfiles_size * sizeof (FILE *));
 230   if (openfiles == 0)
 231     abort ();
 232
 233   /*
 234    * Open up an AF_UNIX socket in this person's home directory
 235    */
 236
 237   if ((s = socket (AF_UNIX, SOCK_STREAM, 0)) < 0)
 238     {
 239       perror_1 ("socket");
 240       exit (1);
 241     }
 242   server.sun_family = AF_UNIX;
 243 #ifndef SERVER_HOME_DIR
 244   gethostname (system_name, sizeof (system_name));
 245   sprintf (server.sun_path, "/tmp/esrv%d-%s", geteuid (), system_name);
 246
 247   if (unlink (server.sun_path) == -1 && errno != ENOENT)
 248     {
 249       perror_1 ("unlink");
 250       exit (1);
 251     }
 252 #else
 253   if ((homedir = getenv ("HOME")) == NULL)
 254     fatal_error ("No home directory\n");
 255
 256   strcpy (server.sun_path, homedir);
 257   strcat (server.sun_path, "/.emacs-server-");
 258   gethostname (system_name, sizeof (system_name));
 259   strcat (server.sun_path, system_name);
 260   /* Delete anyone else's old server.  */
 261   unlink (server.sun_path);
 262 #endif
 263
 264   /* Save the socket name so we can delete it.  */
 265   socket_name = (char *) xmalloc (strlen (server.sun_path) + 1);
 266   strcpy (socket_name, server.sun_path);
 267
 268   handle_signals ();
 269
 270   if (bind (s, (struct sockaddr *) &server, strlen (server.sun_path) + 2) < 0)
 271     {
 272       perror_1 ("bind");
 273       exit (1);
 274     }
 275   /* Only this user can send commands to this Emacs.  */
 276   if (stat (server.sun_path, &statbuf) < 0)
 277     {
 278       perror_1 ("bind");
 279       exit (1);
 280     }
 281
 282   chmod (server.sun_path, statbuf.st_mode & 0600);
 283   /*
 284    * Now, just wait for everything to come in..
 285    */
 286   if (listen (s, 5) < 0)
 287     {
 288       perror_1 ("listen");
 289       exit (1);
 290     }
 291
 292   /* Disable sigpipes in case luser kills client... */
 293   signal (SIGPIPE, SIG_IGN);
 294   for (;;)
 295     {
 296       SELECT_TYPE rmask;
 297       FD_ZERO (&rmask);
 298       FD_SET (0, &rmask);
 299       FD_SET (s, &rmask);
 300       if (select (s + 1, &rmask, 0, 0, 0) < 0)
 301         perror_1 ("select");
 302       if (FD_ISSET (s, &rmask)) /* client sends list of filenames */
 303         {
 304           fromlen = sizeof (fromunix);
 305           fromunix.sun_family = AF_UNIX;
 306           infd = accept (s, (struct sockaddr *) &fromunix, &fromlen);
 307           if (infd < 0)
 308             {
 309               if (errno == EMFILE || errno == ENFILE)
 310                 fprintf (stderr, "Error: too many clients.\n");
 311               else
 312                 perror_1 ("accept");
 313               continue;
 314             }
 315
 316           if (infd >= openfiles_size)
 317             {
 318               openfiles_size *= 2;
 319               openfiles = (FILE **) realloc (openfiles,
 320                                              openfiles_size * sizeof (FILE *));
 321               if (openfiles == 0)
 322                 abort ();
 323             }
 324
 325           infile = fdopen (infd, "r+"); /* open stream */
 326           if (infile == NULL)
 327             {
 328               fprintf (stderr, "Error: too many clients.\n");
 329               write (infd, "Too many clients.\n", 18);
 330               close (infd);             /* Prevent descriptor leak.. */
 331               continue;
 332             }
 333           str = fgets (string, BUFSIZ, infile);
 334           if (str == NULL)
 335             {
 336               perror_1 ("fgets");
 337               close (infd);             /* Prevent descriptor leak.. */
 338               continue;
 339             }
 340           openfiles[infd] = infile;
 341           printf ("Client: %d %s", infd, string);
 342           /* If what we read did not end in a newline,
 343              it means there is more.  Keep reading from the socket
 344              and outputting to Emacs, until we get the newline.  */
 345           while (string[strlen (string) - 1] != '\n')
 346             {
 347               if (fgets (string, BUFSIZ, infile) == 0)
 348                 break;
 349               printf ("%s", string);
 350             }
 351           fflush (stdout);
 352           fflush (infile);
 353           continue;
 354         }
 355       else if (FD_ISSET (0, &rmask)) /* emacs sends codeword, fd, and string message */
 356         {
 357           /* Read command codeword and fd */
 358           clearerr (stdin);
 359           scanf ("%s %d%*c", code, &infd);
 360           if (ferror (stdin) || feof (stdin))
 361             fatal_error ("server: error reading from standard input\n");
 362
 363           /* Transfer text from Emacs to the client, up to a newline.  */
 364           infile = openfiles[infd];
 365           rewind (infile);
 366           while (1)
 367             {
 368               if (fgets (string, BUFSIZ, stdin) == 0)
 369                 break;
 370               fprintf (infile, "%s", string);
 371               if (string[strlen (string) - 1] == '\n')
 372                 break;
 373             }
 374           fflush (infile);
 375
 376           /* If command is close, close connection to client.  */
 377           if (strncmp (code, "Close:", 6) == 0)
 378             if (infd > 2)
 379               {
 380                 fclose (infile);
 381                 close (infd);
 382               }
 383           continue;
 384         }
 385     }
 386 }
 387
 388 #else  /* This is the SYSV IPC section */
 389
 390 #include <sys/types.h>
 391 #include <sys/ipc.h>
 392 #include <sys/msg.h>
 393 #include <setjmp.h>
 394 #include <errno.h>
 395 #include <sys/utsname.h>
 396
 397 struct utsname system_name;
 398
 399 #ifndef errno
 400 extern int errno;
 401 #endif
 402
 403 jmp_buf msgenv;
 404
 405 SIGTYPE
 406 msgcatch ()
 407 {
 408   longjmp (msgenv, 1);
 409 }
 410
 411
 412 /* "THIS has to be fixed.  Remember, stderr may not exist...-rlk."
 413    Incorrect.  This program runs as an inferior of Emacs.
 414    Its stderr always exists--rms.  */
 415 #include <stdio.h>
 416
 417 main ()
 418 {
 419   int s, infd, fromlen, ioproc;
 420   key_t key;
 421   struct msgbuf * msgp =
 422     (struct msgbuf *) malloc (sizeof *msgp + BUFSIZ);
 423   struct msqid_ds msg_st;
 424   int p;
 425   char *homedir, *getenv ();
 426   char string[BUFSIZ];
 427   FILE *infile;
 428
 429   /*
 430    * Create a message queue using ~/.emacs-server as the path for ftok
 431    */
 432   if ((homedir = getenv ("HOME")) == NULL)
 433     fatal_error ("No home directory\n");
 434
 435   strcpy (string, homedir);
 436 #ifndef HAVE_LONG_FILE_NAMES
 437   /* If file names are short, we can't fit the host name.  */
 438   strcat (string, "/.emacs-server");
 439 #else
 440   strcat (string, "/.emacs-server-");
 441   uname (&system_name);
 442   strcat (string, system_name.nodename);
 443 #endif
 444   creat (string, 0600);
 445   key = ftok (string, 1);       /* unlikely to be anyone else using it */
 446   s = msgget (key, 0600 | IPC_CREAT);
 447   if (s == -1)
 448     {
 449       perror_1 ("msgget");
 450       exit (1);
 451     }
 452
 453   /* Fork so we can close connection even if parent dies */
 454   p = fork ();
 455   if (setjmp (msgenv))
 456     {
 457       msgctl (s, IPC_RMID, 0);
 458       if (p > 0)
 459         kill (p, SIGKILL);
 460       exit (0);
 461     }
 462   signal (SIGTERM, msgcatch);
 463   signal (SIGINT, msgcatch);
 464   signal (SIGHUP, msgcatch);
 465   if (p > 0)
 466     {
 467       /* This is executed in the original process that did the fork above.  */
 468       /* Get pid of Emacs itself.  */
 469       p = getppid ();
 470       setpgrp ();               /* Gnu kills process group on exit */
 471       while (1)
 472         {
 473           /* Is Emacs still alive?  */
 474           if (kill (p, 0) < 0)
 475             {
 476               msgctl (s, IPC_RMID, 0);
 477               exit (0);
 478             }
 479           sleep (10);
 480         }
 481     }
 482
 483   /* This is executed in the child made by forking above.
 484      Call it c1.  Make another process, ioproc.  */
 485
 486   ioproc = fork ();
 487   if (ioproc == 0)
 488     {
 489       /* In process ioproc, wait for text from Emacs,
 490          and send it to the process c1.
 491          This way, c1 only has to wait for one source of input.  */
 492       while (fgets (msgp->mtext, BUFSIZ, stdin))
 493         {
 494           msgp->mtype = 1;
 495           msgsnd (s, msgp, strlen (msgp->mtext) + 1, 0);
 496         }
 497       exit (1);
 498     }
 499
 500   /* In the process c1,
 501      listen for messages from clients and pass them to Emacs.  */
 502   while (1)
 503     {
 504       if ((fromlen = msgrcv (s, msgp, BUFSIZ - 1, 1, 0)) < 0)
 505         {
 506 #ifdef EINTR
 507           if (errno == EINTR)
 508             continue;
 509 #endif
 510           perror_1 ("msgrcv");
 511           exit (1);
 512         }
 513       else
 514         {
 515           msgctl (s, IPC_STAT, &msg_st);
 516
 517           /* Distinguish whether the message came from a client, or from
 518              ioproc.  */
 519           if (msg_st.msg_lspid == ioproc)
 520             {
 521               char code[BUFSIZ];
 522               int inproc;
 523
 524               /* Message from ioproc: tell a client we are done.  */
 525               msgp->mtext[strlen (msgp->mtext)-1] = 0;
 526               sscanf (msgp->mtext, "%s %d", code, &inproc);
 527               msgp->mtype = inproc;
 528               msgsnd (s, msgp, strlen (msgp->mtext) + 1, 0);
 529               continue;
 530             }
 531
 532           /* This is a request from a client: copy to stdout
 533              so that Emacs will get it.  Include msg_lspid
 534              so server.el can tell us where to send the reply.  */
 535           strncpy (string, msgp->mtext, fromlen);
 536           string[fromlen] = 0;  /* make sure */
 537           /* Newline is part of string.. */
 538           printf ("Client: %d %s", msg_st.msg_lspid, string);
 539           fflush (stdout);
 540         }
 541     }
 542 }
 543
 544 #endif /* HAVE_SYSVIPC */
 545
 546 #endif /* HAVE_SOCKETS or HAVE_SYSVIPC */
 547 \f
 548 /* This is like perror but puts `Error: ' at the beginning.  */
 549
 550 perror_1 (string)
 551      char *string;
 552 {
 553   char *copy = (char *) malloc (strlen (string) + 8);
 554   if (copy == 0)
 555     fatal_error ("Virtual memory exhausted");
 556
 557   strcpy (copy, "Error: ");
 558   strcat (copy, string);
 559   perror (copy);
 560 }
 561
 562 fatal_error (string)
 563      char *string;
 564 {
 565   fprintf (stderr, "%s", "Error: ");
 566   fprintf (stderr, string);
 567   exit (1);
 568 }