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   size_t fromlen;
 210   struct sockaddr_un server, fromunix;
 211   char *homedir;
 212   char *str, string[BUFSIZ], code[BUFSIZ];
 213   FILE *infile;
 214   FILE **openfiles;
 215   int openfiles_size;
 216   struct stat statbuf;
 217
 218 #ifndef convex
 219   char *getenv ();
 220 #endif
 221
 222   progname = argv[0];
 223
 224   openfiles_size = 20;
 225   openfiles = (FILE **) malloc (openfiles_size * sizeof (FILE *));
 226   if (openfiles == 0)
 227     abort ();
 228
 229   /*
 230    * Open up an AF_UNIX socket in this person's home directory
 231    */
 232
 233   if ((s = socket (AF_UNIX, SOCK_STREAM, 0)) < 0)
 234     {
 235       perror_1 ("socket");
 236       exit (1);
 237     }
 238   server.sun_family = AF_UNIX;
 239 #ifndef SERVER_HOME_DIR
 240   gethostname (system_name, sizeof (system_name));
 241   sprintf (server.sun_path, "/tmp/esrv%d-%s", geteuid (), system_name);
 242
 243   if (unlink (server.sun_path) == -1 && errno != ENOENT)
 244     {
 245       perror_1 ("unlink");
 246       exit (1);
 247     }
 248 #else
 249   if ((homedir = getenv ("HOME")) == NULL)
 250     fatal_error ("No home directory\n");
 251
 252   strcpy (server.sun_path, homedir);
 253   strcat (server.sun_path, "/.emacs-server-");
 254   gethostname (system_name, sizeof (system_name));
 255   strcat (server.sun_path, system_name);
 256   /* Delete anyone else's old server.  */
 257   unlink (server.sun_path);
 258 #endif
 259
 260   /* Save the socket name so we can delete it.  */
 261   socket_name = (char *) xmalloc (strlen (server.sun_path) + 1);
 262   strcpy (socket_name, server.sun_path);
 263
 264   handle_signals ();
 265
 266   if (bind (s, (struct sockaddr *) &server, strlen (server.sun_path) + 2) < 0)
 267     {
 268       perror_1 ("bind");
 269       exit (1);
 270     }
 271   /* Only this user can send commands to this Emacs.  */
 272   if (stat (server.sun_path, &statbuf) < 0)
 273     {
 274       perror_1 ("bind");
 275       exit (1);
 276     }
 277
 278   chmod (server.sun_path, statbuf.st_mode & 0600);
 279   /*
 280    * Now, just wait for everything to come in..
 281    */
 282   if (listen (s, 5) < 0)
 283     {
 284       perror_1 ("listen");
 285       exit (1);
 286     }
 287
 288   /* Disable sigpipes in case luser kills client... */
 289   signal (SIGPIPE, SIG_IGN);
 290   for (;;)
 291     {
 292       SELECT_TYPE rmask;
 293       FD_ZERO (&rmask);
 294       FD_SET (0, &rmask);
 295       FD_SET (s, &rmask);
 296       if (select (s + 1, &rmask, 0, 0, 0) < 0)
 297         perror_1 ("select");
 298       if (FD_ISSET (s, &rmask)) /* client sends list of filenames */
 299         {
 300           fromlen = sizeof (fromunix);
 301           fromunix.sun_family = AF_UNIX;
 302           infd = accept (s, (struct sockaddr *) &fromunix, &fromlen);
 303           if (infd < 0)
 304             {
 305               if (errno == EMFILE || errno == ENFILE)
 306                 fprintf (stderr, "Error: too many clients.\n");
 307               else
 308                 perror_1 ("accept");
 309               continue;
 310             }
 311
 312           if (infd >= openfiles_size)
 313             {
 314               openfiles_size *= 2;
 315               openfiles = (FILE **) realloc (openfiles,
 316                                              openfiles_size * sizeof (FILE *));
 317               if (openfiles == 0)
 318                 abort ();
 319             }
 320
 321           infile = fdopen (infd, "r+"); /* open stream */
 322           if (infile == NULL)
 323             {
 324               fprintf (stderr, "Error: too many clients.\n");
 325               write (infd, "Too many clients.\n", 18);
 326               close (infd);             /* Prevent descriptor leak.. */
 327               continue;
 328             }
 329           str = fgets (string, BUFSIZ, infile);
 330           if (str == NULL)
 331             {
 332               perror_1 ("fgets");
 333               close (infd);             /* Prevent descriptor leak.. */
 334               continue;
 335             }
 336           openfiles[infd] = infile;
 337           printf ("Client: %d %s", infd, string);
 338           /* If what we read did not end in a newline,
 339              it means there is more.  Keep reading from the socket
 340              and outputting to Emacs, until we get the newline.  */
 341           while (string[strlen (string) - 1] != '\n')
 342             {
 343               if (fgets (string, BUFSIZ, infile) == 0)
 344                 break;
 345               printf ("%s", string);
 346             }
 347           fflush (stdout);
 348           fflush (infile);
 349           continue;
 350         }
 351       else if (FD_ISSET (0, &rmask)) /* emacs sends codeword, fd, and string message */
 352         {
 353           /* Read command codeword and fd */
 354           clearerr (stdin);
 355           scanf ("%s %d%*c", code, &infd);
 356           if (ferror (stdin) || feof (stdin))
 357             fatal_error ("server: error reading from standard input\n");
 358
 359           /* Transfer text from Emacs to the client, up to a newline.  */
 360           infile = openfiles[infd];
 361           rewind (infile);
 362           while (1)
 363             {
 364               if (fgets (string, BUFSIZ, stdin) == 0)
 365                 break;
 366               fprintf (infile, "%s", string);
 367               if (string[strlen (string) - 1] == '\n')
 368                 break;
 369             }
 370           fflush (infile);
 371
 372           /* If command is close, close connection to client.  */
 373           if (strncmp (code, "Close:", 6) == 0)
 374             if (infd > 2)
 375               {
 376                 fclose (infile);
 377                 close (infd);
 378               }
 379           continue;
 380         }
 381     }
 382 }
 383
 384 #else  /* This is the SYSV IPC section */
 385
 386 #include <sys/types.h>
 387 #include <sys/ipc.h>
 388 #include <sys/msg.h>
 389 #include <setjmp.h>
 390 #include <errno.h>
 391 #include <sys/utsname.h>
 392
 393 struct utsname system_name;
 394
 395 #ifndef errno
 396 extern int errno;
 397 #endif
 398
 399 jmp_buf msgenv;
 400
 401 SIGTYPE
 402 msgcatch ()
 403 {
 404   longjmp (msgenv, 1);
 405 }
 406
 407
 408 /* "THIS has to be fixed.  Remember, stderr may not exist...-rlk."
 409    Incorrect.  This program runs as an inferior of Emacs.
 410    Its stderr always exists--rms.  */
 411 #include <stdio.h>
 412
 413 main ()
 414 {
 415   int s, infd, fromlen, ioproc;
 416   key_t key;
 417   struct msgbuf * msgp =
 418     (struct msgbuf *) malloc (sizeof *msgp + BUFSIZ);
 419   struct msqid_ds msg_st;
 420   int p;
 421   char *homedir, *getenv ();
 422   char string[BUFSIZ];
 423   FILE *infile;
 424
 425   /*
 426    * Create a message queue using ~/.emacs-server as the path for ftok
 427    */
 428   if ((homedir = getenv ("HOME")) == NULL)
 429     fatal_error ("No home directory\n");
 430
 431   strcpy (string, homedir);
 432 #ifndef HAVE_LONG_FILE_NAMES
 433   /* If file names are short, we can't fit the host name.  */
 434   strcat (string, "/.emacs-server");
 435 #else
 436   strcat (string, "/.emacs-server-");
 437   uname (&system_name);
 438   strcat (string, system_name.nodename);
 439 #endif
 440   creat (string, 0600);
 441   key = ftok (string, 1);       /* unlikely to be anyone else using it */
 442   s = msgget (key, 0600 | IPC_CREAT);
 443   if (s == -1)
 444     {
 445       perror_1 ("msgget");
 446       exit (1);
 447     }
 448
 449   /* Fork so we can close connection even if parent dies */
 450   p = fork ();
 451   if (setjmp (msgenv))
 452     {
 453       msgctl (s, IPC_RMID, 0);
 454       if (p > 0)
 455         kill (p, SIGKILL);
 456       exit (0);
 457     }
 458   signal (SIGTERM, msgcatch);
 459   signal (SIGINT, msgcatch);
 460   signal (SIGHUP, msgcatch);
 461   if (p > 0)
 462     {
 463       /* This is executed in the original process that did the fork above.  */
 464       /* Get pid of Emacs itself.  */
 465       p = getppid ();
 466       setpgrp ();               /* Gnu kills process group on exit */
 467       while (1)
 468         {
 469           /* Is Emacs still alive?  */
 470           if (kill (p, 0) < 0)
 471             {
 472               msgctl (s, IPC_RMID, 0);
 473               exit (0);
 474             }
 475           sleep (10);
 476         }
 477     }
 478
 479   /* This is executed in the child made by forking above.
 480      Call it c1.  Make another process, ioproc.  */
 481
 482   ioproc = fork ();
 483   if (ioproc == 0)
 484     {
 485       /* In process ioproc, wait for text from Emacs,
 486          and send it to the process c1.
 487          This way, c1 only has to wait for one source of input.  */
 488       while (fgets (msgp->mtext, BUFSIZ, stdin))
 489         {
 490           msgp->mtype = 1;
 491           msgsnd (s, msgp, strlen (msgp->mtext) + 1, 0);
 492         }
 493       exit (1);
 494     }
 495
 496   /* In the process c1,
 497      listen for messages from clients and pass them to Emacs.  */
 498   while (1)
 499     {
 500       if ((fromlen = msgrcv (s, msgp, BUFSIZ - 1, 1, 0)) < 0)
 501         {
 502 #ifdef EINTR
 503           if (errno == EINTR)
 504             continue;
 505 #endif
 506           perror_1 ("msgrcv");
 507           exit (1);
 508         }
 509       else
 510         {
 511           msgctl (s, IPC_STAT, &msg_st);
 512
 513           /* Distinguish whether the message came from a client, or from
 514              ioproc.  */
 515           if (msg_st.msg_lspid == ioproc)
 516             {
 517               char code[BUFSIZ];
 518               int inproc;
 519
 520               /* Message from ioproc: tell a client we are done.  */
 521               msgp->mtext[strlen (msgp->mtext)-1] = 0;
 522               sscanf (msgp->mtext, "%s %d", code, &inproc);
 523               msgp->mtype = inproc;
 524               msgsnd (s, msgp, strlen (msgp->mtext) + 1, 0);
 525               continue;
 526             }
 527
 528           /* This is a request from a client: copy to stdout
 529              so that Emacs will get it.  Include msg_lspid
 530              so server.el can tell us where to send the reply.  */
 531           strncpy (string, msgp->mtext, fromlen);
 532           string[fromlen] = 0;  /* make sure */
 533           /* Newline is part of string.. */
 534           printf ("Client: %d %s", msg_st.msg_lspid, string);
 535           fflush (stdout);
 536         }
 537     }
 538 }
 539
 540 #endif /* HAVE_SYSVIPC */
 541
 542 #endif /* HAVE_SOCKETS or HAVE_SYSVIPC */
 543 \f
 544 /* This is like perror but puts `Error: ' at the beginning.  */
 545
 546 perror_1 (string)
 547      char *string;
 548 {
 549   char *copy = (char *) malloc (strlen (string) + 8);
 550   if (copy == 0)
 551     fatal_error ("Virtual memory exhausted");
 552
 553   strcpy (copy, "Error: ");
 554   strcat (copy, string);
 555   perror (copy);
 556 }
 557
 558 fatal_error (string)
 559      char *string;
 560 {
 561   fprintf (stderr, "%s", "Error: ");
 562   fprintf (stderr, string);
 563   exit (1);
 564 }