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