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 int
  41 main ()
  42 {
  43   fprintf (stderr, "Sorry, the Emacs server is supported only on systems\n");
  44   fprintf (stderr, "with Berkeley sockets or System V IPC.\n");
  45   exit (1);
  46 }
  47
  48 #else /* HAVE_SOCKETS or HAVE_SYSVIPC */
  49
  50 void perror_1 ();
  51 void fatal_error ();
  52
  53 #if defined (HAVE_SOCKETS) && ! defined (NO_SOCKETS_IN_FILE_SYSTEM)
  54 /* BSD code is very different from SYSV IPC code */
  55
  56 #include <sys/types.h>
  57 #include <sys/file.h>
  58 #include <sys/socket.h>
  59 #include <sys/un.h>
  60 #include <stdio.h>
  61 #include <errno.h>
  62 #include <sys/stat.h>
  63
  64 #ifdef HAVE_UNISTD_H
  65 #include <unistd.h>
  66 #endif
  67
  68 extern int errno;
  69
  70 /* Copied from src/process.c */
  71 #ifdef FD_SET
  72 /* We could get this from param.h, but better not to depend on finding that.
  73    And better not to risk that it might define other symbols used in this
  74    file.  */
  75 #ifdef FD_SETSIZE
  76 #define MAXDESC FD_SETSIZE
  77 #else
  78 #define MAXDESC 64
  79 #endif
  80 #define SELECT_TYPE fd_set
  81 #else /* no FD_SET */
  82 #define MAXDESC 32
  83 #define SELECT_TYPE int
  84
  85 /* Define the macros to access a single-int bitmap of descriptors.  */
  86 #define FD_SET(n, p) (*(p) |= (1 << (n)))
  87 #define FD_CLR(n, p) (*(p) &= ~(1 << (n)))
  88 #define FD_ISSET(n, p) (*(p) & (1 << (n)))
  89 #define FD_ZERO(p) (*(p) = 0)
  90 #endif /* no FD_SET */
  91
  92 /* This is the file name of the socket that we made.  */
  93
  94 char *socket_name;
  95
  96 /* Name of this program.  */
  97
  98 char *progname;
  99 \f
 100 /* Handle fatal signals.  */
 101
 102 /* This is the handler.  */
 103
 104 SIGTYPE
 105 delete_socket (sig)
 106      int sig;
 107 {
 108   signal (sig, SIG_DFL);
 109   unlink (socket_name);
 110   kill (getpid (), sig);
 111 }
 112
 113 /* Set up to handle all the signals.  */
 114
 115 void
 116 handle_signals ()
 117 {
 118   signal (SIGHUP, delete_socket);
 119   signal (SIGINT, delete_socket);
 120   signal (SIGQUIT, delete_socket);
 121   signal (SIGILL, delete_socket);
 122   signal (SIGTRAP, delete_socket);
 123 #ifdef SIGABRT
 124   signal (SIGABRT, delete_socket);
 125 #endif
 126 #ifdef SIGHWE
 127   signal (SIGHWE, delete_socket);
 128 #endif
 129 #ifdef SIGPRE
 130   signal (SIGPRE, delete_socket);
 131 #endif
 132 #ifdef SIGORE
 133   signal (SIGORE, delete_socket);
 134 #endif
 135 #ifdef SIGUME
 136   signal (SIGUME, delete_socket);
 137 #endif
 138 #ifdef SIGDLK
 139   signal (SIGDLK, delete_socket);
 140 #endif
 141 #ifdef SIGCPULIM
 142   signal (SIGCPULIM, delete_socket);
 143 #endif
 144 #ifdef SIGIOT
 145   /* This is missing on some systems - OS/2, for example.  */
 146   signal (SIGIOT, delete_socket);
 147 #endif
 148 #ifdef SIGEMT
 149   signal (SIGEMT, delete_socket);
 150 #endif
 151   signal (SIGFPE, delete_socket);
 152 #ifdef SIGBUS
 153   signal (SIGBUS, delete_socket);
 154 #endif
 155   signal (SIGSEGV, delete_socket);
 156 #ifdef SIGSYS
 157   signal (SIGSYS, delete_socket);
 158 #endif
 159   signal (SIGTERM, delete_socket);
 160 #ifdef SIGXCPU
 161   signal (SIGXCPU, delete_socket);
 162 #endif
 163 #ifdef SIGXFSZ
 164   signal (SIGXFSZ, delete_socket);
 165 #endif /* SIGXFSZ */
 166
 167 #ifdef AIX
 168 /* 20 is SIGCHLD, 21 is SIGTTIN, 22 is SIGTTOU.  */
 169   signal (SIGXCPU, delete_socket);
 170 #ifndef _I386
 171   signal (SIGIOINT, delete_socket);
 172 #endif
 173   signal (SIGGRANT, delete_socket);
 174   signal (SIGRETRACT, delete_socket);
 175   signal (SIGSOUND, delete_socket);
 176   signal (SIGMSG, delete_socket);
 177 #endif /* AIX */
 178 }
 179 \f
 180 /* Print error message.  `s1' is printf control string, `s2' is arg for it. */
 181 void
 182 error (s1, s2)
 183      char *s1, *s2;
 184 {
 185   fprintf (stderr, "%s: ", progname);
 186   fprintf (stderr, s1, s2);
 187   fprintf (stderr, "\n");
 188 }
 189
 190 /* Print error message and exit.  */
 191 void
 192 fatal (s1, s2)
 193      char *s1, *s2;
 194 {
 195   error (s1, s2);
 196   exit (1);
 197 }
 198
 199 /* Like malloc but get fatal error if memory is exhausted.  */
 200
 201 long *
 202 xmalloc (size)
 203      unsigned int size;
 204 {
 205   long *result = (long *) malloc (size);
 206   if (result == NULL)
 207     fatal ("virtual memory exhausted", 0);
 208   return result;
 209 }
 210 \f
 211 int
 212 main (argc, argv)
 213      int argc;
 214      char **argv;
 215 {
 216   char system_name[32];
 217   int s, infd;
 218 #ifdef SOCKLEN_TYPE
 219   SOCKLEN_TYPE fromlen;
 220 #else
 221   size_t fromlen;
 222 #endif
 223   struct sockaddr_un server, fromunix;
 224   char *homedir;
 225   char *str, string[BUFSIZ], code[BUFSIZ];
 226   FILE *infile;
 227   FILE **openfiles;
 228   int openfiles_size;
 229   struct stat statbuf;
 230
 231 #ifndef convex
 232   char *getenv ();
 233 #endif
 234
 235   progname = argv[0];
 236
 237   openfiles_size = 20;
 238   openfiles = (FILE **) malloc (openfiles_size * sizeof (FILE *));
 239   if (openfiles == 0)
 240     abort ();
 241
 242   /*
 243    * Open up an AF_UNIX socket in this person's home directory
 244    */
 245
 246   if ((s = socket (AF_UNIX, SOCK_STREAM, 0)) < 0)
 247     {
 248       perror_1 ("socket");
 249       exit (1);
 250     }
 251   server.sun_family = AF_UNIX;
 252 #ifndef SERVER_HOME_DIR
 253   gethostname (system_name, sizeof (system_name));
 254   sprintf (server.sun_path, "/tmp/esrv%d-%s", geteuid (), system_name);
 255
 256   if (unlink (server.sun_path) == -1 && errno != ENOENT)
 257     {
 258       perror_1 ("unlink");
 259       exit (1);
 260     }
 261 #else
 262   if ((homedir = getenv ("HOME")) == NULL)
 263     fatal_error ("No home directory\n");
 264
 265   strcpy (server.sun_path, homedir);
 266   strcat (server.sun_path, "/.emacs-server-");
 267   gethostname (system_name, sizeof (system_name));
 268   strcat (server.sun_path, system_name);
 269   /* Delete anyone else's old server.  */
 270   unlink (server.sun_path);
 271 #endif
 272
 273   /* Save the socket name so we can delete it.  */
 274   socket_name = (char *) xmalloc (strlen (server.sun_path) + 1);
 275   strcpy (socket_name, server.sun_path);
 276
 277   handle_signals ();
 278
 279   if (bind (s, (struct sockaddr *) &server, strlen (server.sun_path) + 2) < 0)
 280     {
 281       perror_1 ("bind");
 282       exit (1);
 283     }
 284   /* Only this user can send commands to this Emacs.  */
 285   if (stat (server.sun_path, &statbuf) < 0)
 286     {
 287       perror_1 ("bind");
 288       exit (1);
 289     }
 290
 291   chmod (server.sun_path, statbuf.st_mode & 0600);
 292   /*
 293    * Now, just wait for everything to come in..
 294    */
 295   if (listen (s, 5) < 0)
 296     {
 297       perror_1 ("listen");
 298       exit (1);
 299     }
 300
 301   /* Disable sigpipes in case luser kills client... */
 302   signal (SIGPIPE, SIG_IGN);
 303   for (;;)
 304     {
 305       SELECT_TYPE rmask;
 306       FD_ZERO (&rmask);
 307       FD_SET (0, &rmask);
 308       FD_SET (s, &rmask);
 309       if (select (s + 1, &rmask, 0, 0, 0) < 0)
 310         perror_1 ("select");
 311       if (FD_ISSET (s, &rmask)) /* client sends list of filenames */
 312         {
 313           fromlen = sizeof (fromunix);
 314           fromunix.sun_family = AF_UNIX;
 315           infd = accept (s, (struct sockaddr *) &fromunix, &fromlen);
 316           if (infd < 0)
 317             {
 318               if (errno == EMFILE || errno == ENFILE)
 319                 fprintf (stderr, "Error: too many clients.\n");
 320               else
 321                 perror_1 ("accept");
 322               continue;
 323             }
 324
 325           if (infd >= openfiles_size)
 326             {
 327               openfiles_size *= 2;
 328               openfiles = (FILE **) realloc (openfiles,
 329                                              openfiles_size * sizeof (FILE *));
 330               if (openfiles == 0)
 331                 abort ();
 332             }
 333
 334           infile = fdopen (infd, "r+"); /* open stream */
 335           if (infile == NULL)
 336             {
 337               fprintf (stderr, "Error: too many clients.\n");
 338               write (infd, "Too many clients.\n", 18);
 339               close (infd);             /* Prevent descriptor leak.. */
 340               continue;
 341             }
 342           str = fgets (string, BUFSIZ, infile);
 343           if (str == NULL)
 344             {
 345               perror_1 ("fgets");
 346               close (infd);             /* Prevent descriptor leak.. */
 347               continue;
 348             }
 349           openfiles[infd] = infile;
 350           printf ("Client: %d %s", infd, string);
 351           /* If what we read did not end in a newline,
 352              it means there is more.  Keep reading from the socket
 353              and outputting to Emacs, until we get the newline.  */
 354           while (string[strlen (string) - 1] != '\n')
 355             {
 356               if (fgets (string, BUFSIZ, infile) == 0)
 357                 break;
 358               printf ("%s", string);
 359             }
 360           fflush (stdout);
 361           fflush (infile);
 362           continue;
 363         }
 364       else if (FD_ISSET (0, &rmask)) /* emacs sends codeword, fd, and string message */
 365         {
 366           /* Read command codeword and fd */
 367           clearerr (stdin);
 368           scanf ("%s %d%*c", code, &infd);
 369           if (ferror (stdin) || feof (stdin))
 370             fatal_error ("server: error reading from standard input\n");
 371
 372           /* Transfer text from Emacs to the client, up to a newline.  */
 373           infile = openfiles[infd];
 374           rewind (infile);
 375           while (1)
 376             {
 377               if (fgets (string, BUFSIZ, stdin) == 0)
 378                 break;
 379               fprintf (infile, "%s", string);
 380               if (string[strlen (string) - 1] == '\n')
 381                 break;
 382             }
 383           fflush (infile);
 384
 385           /* If command is close, close connection to client.  */
 386           if (strncmp (code, "Close:", 6) == 0)
 387             if (infd > 2)
 388               {
 389                 fclose (infile);
 390                 close (infd);
 391               }
 392           continue;
 393         }
 394     }
 395 }
 396
 397 #else  /* This is the SYSV IPC section */
 398
 399 #include <sys/types.h>
 400 #include <sys/ipc.h>
 401 #include <sys/msg.h>
 402 #include <setjmp.h>
 403 #include <errno.h>
 404 #include <sys/utsname.h>
 405
 406 struct utsname system_name;
 407
 408 #ifndef errno
 409 extern int errno;
 410 #endif
 411
 412 jmp_buf msgenv;
 413
 414 SIGTYPE
 415 msgcatch ()
 416 {
 417   longjmp (msgenv, 1);
 418 }
 419
 420
 421 /* "THIS has to be fixed.  Remember, stderr may not exist...-rlk."
 422    Incorrect.  This program runs as an inferior of Emacs.
 423    Its stderr always exists--rms.  */
 424 #include <stdio.h>
 425
 426 int
 427 main ()
 428 {
 429   int s, infd, fromlen, ioproc;
 430   key_t key;
 431   struct msgbuf * msgp =
 432     (struct msgbuf *) malloc (sizeof *msgp + BUFSIZ);
 433   struct msqid_ds msg_st;
 434   int p;
 435   char *homedir, *getenv ();
 436   char string[BUFSIZ];
 437   FILE *infile;
 438
 439   /*
 440    * Create a message queue using ~/.emacs-server as the path for ftok
 441    */
 442   if ((homedir = getenv ("HOME")) == NULL)
 443     fatal_error ("No home directory\n");
 444
 445   strcpy (string, homedir);
 446 #ifndef HAVE_LONG_FILE_NAMES
 447   /* If file names are short, we can't fit the host name.  */
 448   strcat (string, "/.emacs-server");
 449 #else
 450   strcat (string, "/.emacs-server-");
 451   uname (&system_name);
 452   strcat (string, system_name.nodename);
 453 #endif
 454   creat (string, 0600);
 455   key = ftok (string, 1);       /* unlikely to be anyone else using it */
 456   s = msgget (key, 0600 | IPC_CREAT);
 457   if (s == -1)
 458     {
 459       perror_1 ("msgget");
 460       exit (1);
 461     }
 462
 463   /* Fork so we can close connection even if parent dies */
 464   p = fork ();
 465   if (setjmp (msgenv))
 466     {
 467       msgctl (s, IPC_RMID, 0);
 468       if (p > 0)
 469         kill (p, SIGKILL);
 470       exit (0);
 471     }
 472   signal (SIGTERM, msgcatch);
 473   signal (SIGINT, msgcatch);
 474   signal (SIGHUP, msgcatch);
 475   if (p > 0)
 476     {
 477       /* This is executed in the original process that did the fork above.  */
 478       /* Get pid of Emacs itself.  */
 479       p = getppid ();
 480       setpgrp ();               /* Gnu kills process group on exit */
 481       while (1)
 482         {
 483           /* Is Emacs still alive?  */
 484           if (kill (p, 0) < 0)
 485             {
 486               msgctl (s, IPC_RMID, 0);
 487               exit (0);
 488             }
 489           sleep (10);
 490         }
 491     }
 492
 493   /* This is executed in the child made by forking above.
 494      Call it c1.  Make another process, ioproc.  */
 495
 496   ioproc = fork ();
 497   if (ioproc == 0)
 498     {
 499       /* In process ioproc, wait for text from Emacs,
 500          and send it to the process c1.
 501          This way, c1 only has to wait for one source of input.  */
 502       while (fgets (msgp->mtext, BUFSIZ, stdin))
 503         {
 504           msgp->mtype = 1;
 505           msgsnd (s, msgp, strlen (msgp->mtext) + 1, 0);
 506         }
 507       exit (1);
 508     }
 509
 510   /* In the process c1,
 511      listen for messages from clients and pass them to Emacs.  */
 512   while (1)
 513     {
 514       if ((fromlen = msgrcv (s, msgp, BUFSIZ - 1, 1, 0)) < 0)
 515         {
 516 #ifdef EINTR
 517           if (errno == EINTR)
 518             continue;
 519 #endif
 520           perror_1 ("msgrcv");
 521           exit (1);
 522         }
 523       else
 524         {
 525           msgctl (s, IPC_STAT, &msg_st);
 526
 527           /* Distinguish whether the message came from a client, or from
 528              ioproc.  */
 529           if (msg_st.msg_lspid == ioproc)
 530             {
 531               char code[BUFSIZ];
 532               int inproc;
 533
 534               /* Message from ioproc: tell a client we are done.  */
 535               msgp->mtext[strlen (msgp->mtext)-1] = 0;
 536               sscanf (msgp->mtext, "%s %d", code, &inproc);
 537               msgp->mtype = inproc;
 538               msgsnd (s, msgp, strlen (msgp->mtext) + 1, 0);
 539               continue;
 540             }
 541
 542           /* This is a request from a client: copy to stdout
 543              so that Emacs will get it.  Include msg_lspid
 544              so server.el can tell us where to send the reply.  */
 545           strncpy (string, msgp->mtext, fromlen);
 546           string[fromlen] = 0;  /* make sure */
 547           /* Newline is part of string.. */
 548           printf ("Client: %d %s", msg_st.msg_lspid, string);
 549           fflush (stdout);
 550         }
 551     }
 552 }
 553
 554 #endif /* HAVE_SYSVIPC */
 555
 556 #endif /* HAVE_SOCKETS or HAVE_SYSVIPC */
 557 \f
 558 /* This is like perror but puts `Error: ' at the beginning.  */
 559
 560 void
 561 perror_1 (string)
 562      char *string;
 563 {
 564   char *copy = (char *) malloc (strlen (string) + 8);
 565   if (copy == 0)
 566     fatal_error ("Virtual memory exhausted");
 567
 568   strcpy (copy, "Error: ");
 569   strcat (copy, string);
 570   perror (copy);
 571 }
 572
 573 void
 574 fatal_error (string)
 575      char *string;
 576 {
 577   fprintf (stderr, "%s", "Error: ");
 578   fprintf (stderr, string);
 579   exit (1);
 580 }