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 #ifdef SERVER_HOME_DIR
 224   char *homedir;
 225 #endif
 226   char *str, string[BUFSIZ], code[BUFSIZ];
 227   FILE *infile;
 228   FILE **openfiles;
 229   int openfiles_size;
 230   struct stat statbuf;
 231
 232 #ifndef convex
 233   char *getenv ();
 234 #endif
 235
 236   progname = argv[0];
 237
 238   openfiles_size = 20;
 239   openfiles = (FILE **) malloc (openfiles_size * sizeof (FILE *));
 240   if (openfiles == 0)
 241     abort ();
 242
 243   /*
 244    * Open up an AF_UNIX socket in this person's home directory
 245    */
 246
 247   if ((s = socket (AF_UNIX, SOCK_STREAM, 0)) < 0)
 248     {
 249       perror_1 ("socket");
 250       exit (1);
 251     }
 252   server.sun_family = AF_UNIX;
 253
 254   system_name_length = 32;
 255   while (1)
 256     {
 257       system_name = (char *) xmalloc (system_name_length + 1);
 258
 259       /* system_name must be null-terminated string.  */
 260       system_name[system_name_length] = '\0';
 261
 262       if (gethostname (system_name, system_name_length) == 0)
 263         break;
 264
 265       free (system_name);
 266       system_name_length *= 2;
 267     }
 268
 269 #ifndef SERVER_HOME_DIR
 270   sprintf (server.sun_path, "/tmp/esrv%d-%s", (int) geteuid (), system_name);
 271
 272   if (unlink (server.sun_path) == -1 && errno != ENOENT)
 273     {
 274       perror_1 ("unlink");
 275       exit (1);
 276     }
 277 #else
 278   if ((homedir = getenv ("HOME")) == NULL)
 279     fatal_error ("No home directory\n");
 280
 281   strcpy (server.sun_path, homedir);
 282   strcat (server.sun_path, "/.emacs-server-");
 283   strcat (server.sun_path, system_name);
 284   /* Delete anyone else's old server.  */
 285   unlink (server.sun_path);
 286 #endif
 287
 288   /* Save the socket name so we can delete it.  */
 289   socket_name = (char *) xmalloc (strlen (server.sun_path) + 1);
 290   strcpy (socket_name, server.sun_path);
 291
 292   handle_signals ();
 293
 294   if (bind (s, (struct sockaddr *) &server, strlen (server.sun_path) + 2) < 0)
 295     {
 296       perror_1 ("bind");
 297       exit (1);
 298     }
 299   /* Only this user can send commands to this Emacs.  */
 300   if (stat (server.sun_path, &statbuf) < 0)
 301     {
 302       perror_1 ("bind");
 303       exit (1);
 304     }
 305
 306   chmod (server.sun_path, statbuf.st_mode & 0600);
 307   /*
 308    * Now, just wait for everything to come in..
 309    */
 310   if (listen (s, 5) < 0)
 311     {
 312       perror_1 ("listen");
 313       exit (1);
 314     }
 315
 316   /* Disable sigpipes in case luser kills client... */
 317   signal (SIGPIPE, SIG_IGN);
 318   for (;;)
 319     {
 320       SELECT_TYPE rmask;
 321       FD_ZERO (&rmask);
 322       FD_SET (0, &rmask);
 323       FD_SET (s, &rmask);
 324       if (select (s + 1, &rmask, 0, 0, 0) < 0)
 325         perror_1 ("select");
 326       if (FD_ISSET (s, &rmask)) /* client sends list of filenames */
 327         {
 328           fromlen = sizeof (fromunix);
 329           fromunix.sun_family = AF_UNIX;
 330           infd = accept (s, (struct sockaddr *) &fromunix, &fromlen);
 331           if (infd < 0)
 332             {
 333               if (errno == EMFILE || errno == ENFILE)
 334                 fprintf (stderr, "Error: too many clients.\n");
 335               else
 336                 perror_1 ("accept");
 337               continue;
 338             }
 339
 340           if (infd >= openfiles_size)
 341             {
 342               openfiles_size *= 2;
 343               openfiles = (FILE **) realloc (openfiles,
 344                                              openfiles_size * sizeof (FILE *));
 345               if (openfiles == 0)
 346                 abort ();
 347             }
 348
 349           infile = fdopen (infd, "r+"); /* open stream */
 350           if (infile == NULL)
 351             {
 352               fprintf (stderr, "Error: too many clients.\n");
 353               write (infd, "Too many clients.\n", 18);
 354               close (infd);             /* Prevent descriptor leak.. */
 355               continue;
 356             }
 357           str = fgets (string, BUFSIZ, infile);
 358           if (str == NULL)
 359             {
 360               perror_1 ("fgets");
 361               close (infd);             /* Prevent descriptor leak.. */
 362               continue;
 363             }
 364           openfiles[infd] = infile;
 365           printf ("Client: %d %s", infd, string);
 366           /* If what we read did not end in a newline,
 367              it means there is more.  Keep reading from the socket
 368              and outputting to Emacs, until we get the newline.  */
 369           while (string[strlen (string) - 1] != '\n')
 370             {
 371               if (fgets (string, BUFSIZ, infile) == 0)
 372                 break;
 373               printf ("%s", string);
 374             }
 375           fflush (stdout);
 376           fflush (infile);
 377           continue;
 378         }
 379       else if (FD_ISSET (0, &rmask)) /* emacs sends codeword, fd, and string message */
 380         {
 381           /* Read command codeword and fd */
 382           clearerr (stdin);
 383           scanf ("%s %d%*c", code, &infd);
 384           if (ferror (stdin) || feof (stdin))
 385             fatal_error ("server: error reading from standard input\n");
 386
 387           /* Transfer text from Emacs to the client, up to a newline.  */
 388           infile = openfiles[infd];
 389           rewind (infile);
 390           while (1)
 391             {
 392               if (fgets (string, BUFSIZ, stdin) == 0)
 393                 break;
 394               fprintf (infile, "%s", string);
 395               if (string[strlen (string) - 1] == '\n')
 396                 break;
 397             }
 398           fflush (infile);
 399
 400           /* If command is close, close connection to client.  */
 401           if (strncmp (code, "Close:", 6) == 0)
 402             if (infd > 2)
 403               {
 404                 fclose (infile);
 405                 close (infd);
 406               }
 407           continue;
 408         }
 409     }
 410 }
 411
 412 #else  /* This is the SYSV IPC section */
 413
 414 #include <sys/types.h>
 415 #include <sys/ipc.h>
 416 #include <sys/msg.h>
 417 #include <setjmp.h>
 418 #include <errno.h>
 419 #include <sys/utsname.h>
 420
 421 struct utsname system_name;
 422
 423 #ifndef errno
 424 extern int errno;
 425 #endif
 426
 427 jmp_buf msgenv;
 428
 429 SIGTYPE
 430 msgcatch ()
 431 {
 432   longjmp (msgenv, 1);
 433 }
 434
 435
 436 /* "THIS has to be fixed.  Remember, stderr may not exist...-rlk."
 437    Incorrect.  This program runs as an inferior of Emacs.
 438    Its stderr always exists--rms.  */
 439 #include <stdio.h>
 440
 441 int
 442 main ()
 443 {
 444   int s, infd, fromlen, ioproc;
 445   key_t key;
 446   struct msgbuf * msgp =
 447     (struct msgbuf *) malloc (sizeof *msgp + BUFSIZ);
 448   struct msqid_ds msg_st;
 449   int p;
 450   char *homedir, *getenv ();
 451   char string[BUFSIZ];
 452   FILE *infile;
 453
 454   /*
 455    * Create a message queue using ~/.emacs-server as the path for ftok
 456    */
 457   if ((homedir = getenv ("HOME")) == NULL)
 458     fatal_error ("No home directory\n");
 459
 460   strcpy (string, homedir);
 461 #ifndef HAVE_LONG_FILE_NAMES
 462   /* If file names are short, we can't fit the host name.  */
 463   strcat (string, "/.emacs-server");
 464 #else
 465   strcat (string, "/.emacs-server-");
 466   uname (&system_name);
 467   strcat (string, system_name.nodename);
 468 #endif
 469   creat (string, 0600);
 470   key = ftok (string, 1);       /* unlikely to be anyone else using it */
 471   s = msgget (key, 0600 | IPC_CREAT);
 472   if (s == -1)
 473     {
 474       perror_1 ("msgget");
 475       exit (1);
 476     }
 477
 478   /* Fork so we can close connection even if parent dies */
 479   p = fork ();
 480   if (setjmp (msgenv))
 481     {
 482       msgctl (s, IPC_RMID, 0);
 483       if (p > 0)
 484         kill (p, SIGKILL);
 485       exit (0);
 486     }
 487   signal (SIGTERM, msgcatch);
 488   signal (SIGINT, msgcatch);
 489   signal (SIGHUP, msgcatch);
 490   if (p > 0)
 491     {
 492       /* This is executed in the original process that did the fork above.  */
 493       /* Get pid of Emacs itself.  */
 494       p = getppid ();
 495       setpgrp ();               /* Gnu kills process group on exit */
 496       while (1)
 497         {
 498           /* Is Emacs still alive?  */
 499           if (kill (p, 0) < 0)
 500             {
 501               msgctl (s, IPC_RMID, 0);
 502               exit (0);
 503             }
 504           sleep (10);
 505         }
 506     }
 507
 508   /* This is executed in the child made by forking above.
 509      Call it c1.  Make another process, ioproc.  */
 510
 511   ioproc = fork ();
 512   if (ioproc == 0)
 513     {
 514       /* In process ioproc, wait for text from Emacs,
 515          and send it to the process c1.
 516          This way, c1 only has to wait for one source of input.  */
 517       while (fgets (msgp->mtext, BUFSIZ, stdin))
 518         {
 519           msgp->mtype = 1;
 520           msgsnd (s, msgp, strlen (msgp->mtext) + 1, 0);
 521         }
 522       exit (1);
 523     }
 524
 525   /* In the process c1,
 526      listen for messages from clients and pass them to Emacs.  */
 527   while (1)
 528     {
 529       if ((fromlen = msgrcv (s, msgp, BUFSIZ - 1, 1, 0)) < 0)
 530         {
 531 #ifdef EINTR
 532           if (errno == EINTR)
 533             continue;
 534 #endif
 535           perror_1 ("msgrcv");
 536           exit (1);
 537         }
 538       else
 539         {
 540           msgctl (s, IPC_STAT, &msg_st);
 541
 542           /* Distinguish whether the message came from a client, or from
 543              ioproc.  */
 544           if (msg_st.msg_lspid == ioproc)
 545             {
 546               char code[BUFSIZ];
 547               int inproc;
 548
 549               /* Message from ioproc: tell a client we are done.  */
 550               msgp->mtext[strlen (msgp->mtext)-1] = 0;
 551               sscanf (msgp->mtext, "%s %d", code, &inproc);
 552               msgp->mtype = inproc;
 553               msgsnd (s, msgp, strlen (msgp->mtext) + 1, 0);
 554               continue;
 555             }
 556
 557           /* This is a request from a client: copy to stdout
 558              so that Emacs will get it.  Include msg_lspid
 559              so server.el can tell us where to send the reply.  */
 560           strncpy (string, msgp->mtext, fromlen);
 561           string[fromlen] = 0;  /* make sure */
 562           /* Newline is part of string.. */
 563           printf ("Client: %d %s", msg_st.msg_lspid, string);
 564           fflush (stdout);
 565         }
 566     }
 567 }
 568
 569 #endif /* HAVE_SYSVIPC */
 570
 571 \f
 572 /* This is like perror but puts `Error: ' at the beginning.  */
 573
 574 void
 575 perror_1 (string)
 576      char *string;
 577 {
 578   char *copy = (char *) malloc (strlen (string) + 8);
 579   if (copy == 0)
 580     fatal_error ("Virtual memory exhausted");
 581
 582   strcpy (copy, "Error: ");
 583   strcat (copy, string);
 584   perror (copy);
 585 }
 586
 587 void
 588 fatal_error (string)
 589      char *string;
 590 {
 591   fprintf (stderr, "%s", "Error: ");
 592   fprintf (stderr, string);
 593   exit (1);
 594 }
 595 #endif /* HAVE_SOCKETS or HAVE_SYSVIPC */