lib-src/emacsserver.c

   1 /* Communication subprocess for GNU Emacs acting as server.
   2    Copyright (C) 1986, 1987, 1992, 1994, 1999 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 <../src/config.h>
  30 #include <signal.h>
  31 #undef signal
  32
  33 #if !defined (HAVE_SOCKETS) && !defined (HAVE_SYSVIPC)
  34 #include <stdio.h>
  35
  36 int
  37 main ()
  38 {
  39   fprintf (stderr, "Sorry, the Emacs server is supported only on systems\n");
  40   fprintf (stderr, "with Berkeley sockets or System V IPC.\n");
  41   exit (1);
  42 }
  43
  44 #else /* HAVE_SOCKETS or HAVE_SYSVIPC */
  45
  46 void perror_1 ();
  47 void fatal_error ();
  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 #ifdef HAVE_UNISTD_H
  61 #include <unistd.h>
  62 #endif
  63
  64 #ifndef errno
  65 extern int errno;
  66 #endif
  67
  68 /* Copied from src/process.c */
  69 #ifdef FD_SET
  70 /* We could get this from param.h, but better not to depend on finding that.
  71    And better not to risk that it might define other symbols used in this
  72    file.  */
  73 #ifdef FD_SETSIZE
  74 #define MAXDESC FD_SETSIZE
  75 #else
  76 #define MAXDESC 64
  77 #endif
  78 #define SELECT_TYPE fd_set
  79 #else /* no FD_SET */
  80 #define MAXDESC 32
  81 #define SELECT_TYPE int
  82
  83 /* Define the macros to access a single-int bitmap of descriptors.  */
  84 #define FD_SET(n, p) (*(p) |= (1 << (n)))
  85 #define FD_CLR(n, p) (*(p) &= ~(1 << (n)))
  86 #define FD_ISSET(n, p) (*(p) & (1 << (n)))
  87 #define FD_ZERO(p) (*(p) = 0)
  88 #endif /* no FD_SET */
  89
  90 /* This is the file name of the socket that we made.  */
  91
  92 char *socket_name;
  93
  94 /* Name of this program.  */
  95
  96 char *progname;
  97 \f
  98 /* Handle fatal signals.  */
  99
 100 /* This is the handler.  */
 101
 102 SIGTYPE
 103 delete_socket (sig)
 104      int sig;
 105 {
 106   signal (sig, SIG_DFL);
 107   unlink (socket_name);
 108   kill (getpid (), sig);
 109 }
 110
 111 /* Set up to handle all the signals.  */
 112
 113 void
 114 handle_signals ()
 115 {
 116   signal (SIGHUP, delete_socket);
 117   signal (SIGINT, delete_socket);
 118   signal (SIGQUIT, delete_socket);
 119   signal (SIGILL, delete_socket);
 120   signal (SIGTRAP, delete_socket);
 121 #ifdef SIGABRT
 122   signal (SIGABRT, delete_socket);
 123 #endif
 124 #ifdef SIGHWE
 125   signal (SIGHWE, delete_socket);
 126 #endif
 127 #ifdef SIGPRE
 128   signal (SIGPRE, delete_socket);
 129 #endif
 130 #ifdef SIGORE
 131   signal (SIGORE, delete_socket);
 132 #endif
 133 #ifdef SIGUME
 134   signal (SIGUME, delete_socket);
 135 #endif
 136 #ifdef SIGDLK
 137   signal (SIGDLK, delete_socket);
 138 #endif
 139 #ifdef SIGCPULIM
 140   signal (SIGCPULIM, delete_socket);
 141 #endif
 142 #ifdef SIGIOT
 143   /* This is missing on some systems - OS/2, for example.  */
 144   signal (SIGIOT, delete_socket);
 145 #endif
 146 #ifdef SIGEMT
 147   signal (SIGEMT, delete_socket);
 148 #endif
 149   signal (SIGFPE, delete_socket);
 150 #ifdef SIGBUS
 151   signal (SIGBUS, delete_socket);
 152 #endif
 153   signal (SIGSEGV, delete_socket);
 154 #ifdef SIGSYS
 155   signal (SIGSYS, delete_socket);
 156 #endif
 157   signal (SIGTERM, delete_socket);
 158 #ifdef SIGXCPU
 159   signal (SIGXCPU, delete_socket);
 160 #endif
 161 #ifdef SIGXFSZ
 162   signal (SIGXFSZ, delete_socket);
 163 #endif /* SIGXFSZ */
 164
 165 #ifdef AIX
 166 /* 20 is SIGCHLD, 21 is SIGTTIN, 22 is SIGTTOU.  */
 167   signal (SIGXCPU, delete_socket);
 168 #ifndef _I386
 169   signal (SIGIOINT, delete_socket);
 170 #endif
 171   signal (SIGGRANT, delete_socket);
 172   signal (SIGRETRACT, delete_socket);
 173   signal (SIGSOUND, delete_socket);
 174   signal (SIGMSG, delete_socket);
 175 #endif /* AIX */
 176 }
 177 \f
 178 /* Print error message.  `s1' is printf control string, `s2' is arg for it. */
 179 void
 180 error (s1, s2)
 181      char *s1, *s2;
 182 {
 183   fprintf (stderr, "%s: ", progname);
 184   fprintf (stderr, s1, s2);
 185   fprintf (stderr, "\n");
 186 }
 187
 188 /* Print error message and exit.  */
 189 void
 190 fatal (s1, s2)
 191      char *s1, *s2;
 192 {
 193   error (s1, s2);
 194   exit (1);
 195 }
 196
 197 /* Like malloc but get fatal error if memory is exhausted.  */
 198
 199 long *
 200 xmalloc (size)
 201      unsigned int size;
 202 {
 203   long *result = (long *) malloc (size);
 204   if (result == NULL)
 205     fatal ("virtual memory exhausted", 0);
 206   return result;
 207 }
 208 \f
 209 int
 210 main (argc, argv)
 211      int argc;
 212      char **argv;
 213 {
 214   char *system_name;
 215   int system_name_length;
 216   int s, infd;
 217 #ifdef SOCKLEN_TYPE
 218   SOCKLEN_TYPE fromlen;
 219 #else
 220   size_t fromlen;
 221 #endif
 222   struct sockaddr_un server, fromunix;
 223   char *homedir;
 224   char *str, string[BUFSIZ], code[BUFSIZ];
 225   FILE *infile;
 226   FILE **openfiles;
 227   int openfiles_size;
 228   struct stat statbuf;
 229
 230 #ifndef convex
 231   char *getenv ();
 232 #endif
 233
 234   progname = argv[0];
 235
 236   openfiles_size = 20;
 237   openfiles = (FILE **) malloc (openfiles_size * sizeof (FILE *));
 238   if (openfiles == 0)
 239     abort ();
 240
 241   /*
 242    * Open up an AF_UNIX socket in this person's home directory
 243    */
 244
 245   if ((s = socket (AF_UNIX, SOCK_STREAM, 0)) < 0)
 246     {
 247       perror_1 ("socket");
 248       exit (1);
 249     }
 250   server.sun_family = AF_UNIX;
 251
 252   system_name_length = 32;
 253   while (1)
 254     {
 255       system_name = (char *) xmalloc (system_name_length + 1);
 256
 257       /* system_name must be null-terminated string.  */
 258       system_name[system_name_length] = '\0';
 259
 260       if (gethostname (system_name, system_name_length) == 0)
 261         break;
 262
 263       free (system_name);
 264       system_name_length *= 2;
 265     }
 266
 267 #ifndef SERVER_HOME_DIR
 268   sprintf (server.sun_path, "/tmp/esrv%d-%s", geteuid (), system_name);
 269
 270   if (unlink (server.sun_path) == -1 && errno != ENOENT)
 271     {
 272       perror_1 ("unlink");
 273       exit (1);
 274     }
 275 #else
 276   if ((homedir = getenv ("HOME")) == NULL)
 277     fatal_error ("No home directory\n");
 278
 279   strcpy (server.sun_path, homedir);
 280   strcat (server.sun_path, "/.emacs-server-");
 281   strcat (server.sun_path, system_name);
 282   /* Delete anyone else's old server.  */
 283   unlink (server.sun_path);
 284 #endif
 285
 286   /* Save the socket name so we can delete it.  */
 287   socket_name = (char *) xmalloc (strlen (server.sun_path) + 1);
 288   strcpy (socket_name, server.sun_path);
 289
 290   handle_signals ();
 291
 292   if (bind (s, (struct sockaddr *) &server, strlen (server.sun_path) + 2) < 0)
 293     {
 294       perror_1 ("bind");
 295       exit (1);
 296     }
 297   /* Only this user can send commands to this Emacs.  */
 298   if (stat (server.sun_path, &statbuf) < 0)
 299     {
 300       perror_1 ("bind");
 301       exit (1);
 302     }
 303
 304   chmod (server.sun_path, statbuf.st_mode & 0600);
 305   /*
 306    * Now, just wait for everything to come in..
 307    */
 308   if (listen (s, 5) < 0)
 309     {
 310       perror_1 ("listen");
 311       exit (1);
 312     }
 313
 314   /* Disable sigpipes in case luser kills client... */
 315   signal (SIGPIPE, SIG_IGN);
 316   for (;;)
 317     {
 318       SELECT_TYPE rmask;
 319       FD_ZERO (&rmask);
 320       FD_SET (0, &rmask);
 321       FD_SET (s, &rmask);
 322       if (select (s + 1, &rmask, 0, 0, 0) < 0)
 323         perror_1 ("select");
 324       if (FD_ISSET (s, &rmask)) /* client sends list of filenames */
 325         {
 326           fromlen = sizeof (fromunix);
 327           fromunix.sun_family = AF_UNIX;
 328           infd = accept (s, (struct sockaddr *) &fromunix, &fromlen);
 329           if (infd < 0)
 330             {
 331               if (errno == EMFILE || errno == ENFILE)
 332                 fprintf (stderr, "Error: too many clients.\n");
 333               else
 334                 perror_1 ("accept");
 335               continue;
 336             }
 337
 338           if (infd >= openfiles_size)
 339             {
 340               openfiles_size *= 2;
 341               openfiles = (FILE **) realloc (openfiles,
 342                                              openfiles_size * sizeof (FILE *));
 343               if (openfiles == 0)
 344                 abort ();
 345             }
 346
 347           infile = fdopen (infd, "r+"); /* open stream */
 348           if (infile == NULL)
 349             {
 350               fprintf (stderr, "Error: too many clients.\n");
 351               write (infd, "Too many clients.\n", 18);
 352               close (infd);             /* Prevent descriptor leak.. */
 353               continue;
 354             }
 355           str = fgets (string, BUFSIZ, infile);
 356           if (str == NULL)
 357             {
 358               perror_1 ("fgets");
 359               close (infd);             /* Prevent descriptor leak.. */
 360               continue;
 361             }
 362           openfiles[infd] = infile;
 363           printf ("Client: %d %s", infd, string);
 364           /* If what we read did not end in a newline,
 365              it means there is more.  Keep reading from the socket
 366              and outputting to Emacs, until we get the newline.  */
 367           while (string[strlen (string) - 1] != '\n')
 368             {
 369               if (fgets (string, BUFSIZ, infile) == 0)
 370                 break;
 371               printf ("%s", string);
 372             }
 373           fflush (stdout);
 374           fflush (infile);
 375           continue;
 376         }
 377       else if (FD_ISSET (0, &rmask)) /* emacs sends codeword, fd, and string message */
 378         {
 379           /* Read command codeword and fd */
 380           clearerr (stdin);
 381           scanf ("%s %d%*c", code, &infd);
 382           if (ferror (stdin) || feof (stdin))
 383             fatal_error ("server: error reading from standard input\n");
 384
 385           /* Transfer text from Emacs to the client, up to a newline.  */
 386           infile = openfiles[infd];
 387           rewind (infile);
 388           while (1)
 389             {
 390               if (fgets (string, BUFSIZ, stdin) == 0)
 391                 break;
 392               fprintf (infile, "%s", string);
 393               if (string[strlen (string) - 1] == '\n')
 394                 break;
 395             }
 396           fflush (infile);
 397
 398           /* If command is close, close connection to client.  */
 399           if (strncmp (code, "Close:", 6) == 0)
 400             if (infd > 2)
 401               {
 402                 fclose (infile);
 403                 close (infd);
 404               }
 405           continue;
 406         }
 407     }
 408 }
 409
 410 #else  /* This is the SYSV IPC section */
 411
 412 #include <sys/types.h>
 413 #include <sys/ipc.h>
 414 #include <sys/msg.h>
 415 #include <setjmp.h>
 416 #include <errno.h>
 417 #include <sys/utsname.h>
 418
 419 struct utsname system_name;
 420
 421 #ifndef errno
 422 extern int errno;
 423 #endif
 424
 425 jmp_buf msgenv;
 426
 427 SIGTYPE
 428 msgcatch ()
 429 {
 430   longjmp (msgenv, 1);
 431 }
 432
 433
 434 /* "THIS has to be fixed.  Remember, stderr may not exist...-rlk."
 435    Incorrect.  This program runs as an inferior of Emacs.
 436    Its stderr always exists--rms.  */
 437 #include <stdio.h>
 438
 439 int
 440 main ()
 441 {
 442   int s, infd, fromlen, ioproc;
 443   key_t key;
 444   struct msgbuf * msgp =
 445     (struct msgbuf *) malloc (sizeof *msgp + BUFSIZ);
 446   struct msqid_ds msg_st;
 447   int p;
 448   char *homedir, *getenv ();
 449   char string[BUFSIZ];
 450   FILE *infile;
 451
 452   /*
 453    * Create a message queue using ~/.emacs-server as the path for ftok
 454    */
 455   if ((homedir = getenv ("HOME")) == NULL)
 456     fatal_error ("No home directory\n");
 457
 458   strcpy (string, homedir);
 459 #ifndef HAVE_LONG_FILE_NAMES
 460   /* If file names are short, we can't fit the host name.  */
 461   strcat (string, "/.emacs-server");
 462 #else
 463   strcat (string, "/.emacs-server-");
 464   uname (&system_name);
 465   strcat (string, system_name.nodename);
 466 #endif
 467   creat (string, 0600);
 468   key = ftok (string, 1);       /* unlikely to be anyone else using it */
 469   s = msgget (key, 0600 | IPC_CREAT);
 470   if (s == -1)
 471     {
 472       perror_1 ("msgget");
 473       exit (1);
 474     }
 475
 476   /* Fork so we can close connection even if parent dies */
 477   p = fork ();
 478   if (setjmp (msgenv))
 479     {
 480       msgctl (s, IPC_RMID, 0);
 481       if (p > 0)
 482         kill (p, SIGKILL);
 483       exit (0);
 484     }
 485   signal (SIGTERM, msgcatch);
 486   signal (SIGINT, msgcatch);
 487   signal (SIGHUP, msgcatch);
 488   if (p > 0)
 489     {
 490       /* This is executed in the original process that did the fork above.  */
 491       /* Get pid of Emacs itself.  */
 492       p = getppid ();
 493       setpgrp ();               /* Gnu kills process group on exit */
 494       while (1)
 495         {
 496           /* Is Emacs still alive?  */
 497           if (kill (p, 0) < 0)
 498             {
 499               msgctl (s, IPC_RMID, 0);
 500               exit (0);
 501             }
 502           sleep (10);
 503         }
 504     }
 505
 506   /* This is executed in the child made by forking above.
 507      Call it c1.  Make another process, ioproc.  */
 508
 509   ioproc = fork ();
 510   if (ioproc == 0)
 511     {
 512       /* In process ioproc, wait for text from Emacs,
 513          and send it to the process c1.
 514          This way, c1 only has to wait for one source of input.  */
 515       while (fgets (msgp->mtext, BUFSIZ, stdin))
 516         {
 517           msgp->mtype = 1;
 518           msgsnd (s, msgp, strlen (msgp->mtext) + 1, 0);
 519         }
 520       exit (1);
 521     }
 522
 523   /* In the process c1,
 524      listen for messages from clients and pass them to Emacs.  */
 525   while (1)
 526     {
 527       if ((fromlen = msgrcv (s, msgp, BUFSIZ - 1, 1, 0)) < 0)
 528         {
 529 #ifdef EINTR
 530           if (errno == EINTR)
 531             continue;
 532 #endif
 533           perror_1 ("msgrcv");
 534           exit (1);
 535         }
 536       else
 537         {
 538           msgctl (s, IPC_STAT, &msg_st);
 539
 540           /* Distinguish whether the message came from a client, or from
 541              ioproc.  */
 542           if (msg_st.msg_lspid == ioproc)
 543             {
 544               char code[BUFSIZ];
 545               int inproc;
 546
 547               /* Message from ioproc: tell a client we are done.  */
 548               msgp->mtext[strlen (msgp->mtext)-1] = 0;
 549               sscanf (msgp->mtext, "%s %d", code, &inproc);
 550               msgp->mtype = inproc;
 551               msgsnd (s, msgp, strlen (msgp->mtext) + 1, 0);
 552               continue;
 553             }
 554
 555           /* This is a request from a client: copy to stdout
 556              so that Emacs will get it.  Include msg_lspid
 557              so server.el can tell us where to send the reply.  */
 558           strncpy (string, msgp->mtext, fromlen);
 559           string[fromlen] = 0;  /* make sure */
 560           /* Newline is part of string.. */
 561           printf ("Client: %d %s", msg_st.msg_lspid, string);
 562           fflush (stdout);
 563         }
 564     }
 565 }
 566
 567 #endif /* HAVE_SYSVIPC */
 568
 569 \f
 570 /* This is like perror but puts `Error: ' at the beginning.  */
 571
 572 void
 573 perror_1 (string)
 574      char *string;
 575 {
 576   char *copy = (char *) malloc (strlen (string) + 8);
 577   if (copy == 0)
 578     fatal_error ("Virtual memory exhausted");
 579
 580   strcpy (copy, "Error: ");
 581   strcat (copy, string);
 582   perror (copy);
 583 }
 584
 585 void
 586 fatal_error (string)
 587      char *string;
 588 {
 589   fprintf (stderr, "%s", "Error: ");
 590   fprintf (stderr, string);
 591   exit (1);
 592 }
 593 #endif /* HAVE_SOCKETS or HAVE_SYSVIPC */