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 <../src/config.h>
  30 #undef read
  31 #undef write
  32 #undef open
  33 #undef close
  34 #undef signal
  35
  36 #if !defined (HAVE_SOCKETS) && !defined (HAVE_SYSVIPC)
  37 #include <stdio.h>
  38
  39 main ()
  40 {
  41   fprintf (stderr, "Sorry, the Emacs server is supported only on systems\n");
  42   fprintf (stderr, "with Berkeley sockets or System V IPC.\n");
  43   exit (1);
  44 }
  45
  46 #else /* HAVE_SOCKETS or HAVE_SYSVIPC */
  47
  48 #if defined (HAVE_SOCKETS) && ! defined (NO_SOCKETS_IN_FILE_SYSTEM)
  49 /* BSD code is very different from SYSV IPC code */
  50
  51 #include <sys/types.h>
  52 #include <sys/file.h>
  53 #include <sys/socket.h>
  54 #include <sys/signal.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 main ()
  85 {
  86   char system_name[32];
  87   int s, infd, fromlen;
  88   struct sockaddr_un server, fromunix;
  89   char *homedir;
  90   char *str, string[BUFSIZ], code[BUFSIZ];
  91   FILE *infile;
  92   FILE **openfiles;
  93   int openfiles_size;
  94   struct stat statbuf;
  95
  96 #ifndef convex
  97   char *getenv ();
  98 #endif
  99
 100   openfiles_size = 20;
 101   openfiles = (FILE **) malloc (openfiles_size * sizeof (FILE *));
 102   if (openfiles == 0)
 103     abort ();
 104
 105   /*
 106    * Open up an AF_UNIX socket in this person's home directory
 107    */
 108
 109   if ((s = socket (AF_UNIX, SOCK_STREAM, 0)) < 0)
 110     {
 111       perror_1 ("socket");
 112       exit (1);
 113     }
 114   server.sun_family = AF_UNIX;
 115 #ifndef SERVER_HOME_DIR
 116   gethostname (system_name, sizeof (system_name));
 117   sprintf (server.sun_path, "/tmp/esrv%d-%s", geteuid (), system_name);
 118
 119   if (unlink (server.sun_path) == -1 && errno != ENOENT)
 120     {
 121       perror_1 ("unlink");
 122       exit (1);
 123     }
 124 #else
 125   if ((homedir = getenv ("HOME")) == NULL)
 126     fatal_error ("No home directory\n");
 127
 128   strcpy (server.sun_path, homedir);
 129   strcat (server.sun_path, "/.emacs-server-");
 130   gethostname (system_name, sizeof (system_name));
 131   strcat (server.sun_path, system_name);
 132   /* Delete anyone else's old server.  */
 133   unlink (server.sun_path);
 134 #endif
 135
 136   if (bind (s, (struct sockaddr *) &server, strlen (server.sun_path) + 2) < 0)
 137     {
 138       perror_1 ("bind");
 139       exit (1);
 140     }
 141   /* Only this user can send commands to this Emacs.  */
 142   if (stat (server.sun_path, &statbuf) < 0)
 143     {
 144       perror_1 ("bind");
 145       exit (1);
 146     }
 147
 148   chmod (server.sun_path, statbuf.st_mode & 0600);
 149   /*
 150    * Now, just wait for everything to come in..
 151    */
 152   if (listen (s, 5) < 0)
 153     {
 154       perror_1 ("listen");
 155       exit (1);
 156     }
 157
 158   /* Disable sigpipes in case luser kills client... */
 159   signal (SIGPIPE, SIG_IGN);
 160   for (;;)
 161     {
 162       SELECT_TYPE rmask;
 163       FD_ZERO (&rmask);
 164       FD_SET (0, &rmask);
 165       FD_SET (s, &rmask);
 166       if (select (s + 1, &rmask, 0, 0, 0) < 0)
 167         perror_1 ("select");
 168       if (FD_ISSET (s, &rmask)) /* client sends list of filenames */
 169         {
 170           fromlen = sizeof (fromunix);
 171           fromunix.sun_family = AF_UNIX;
 172           infd = accept (s, (struct sockaddr *) &fromunix, &fromlen);
 173           if (infd < 0)
 174             {
 175               if (errno == EMFILE || errno == ENFILE)
 176                 fprintf (stderr, "Error: too many clients.\n");
 177               else
 178                 perror_1 ("accept");
 179               continue;
 180             }
 181
 182           if (infd >= openfiles_size)
 183             {
 184               openfiles_size *= 2;
 185               openfiles = (FILE **) realloc (openfiles,
 186                                              openfiles_size * sizeof (FILE *));
 187               if (openfiles == 0)
 188                 abort ();
 189             }
 190
 191           infile = fdopen (infd, "r+"); /* open stream */
 192           if (infile == NULL)
 193             {
 194               fprintf (stderr, "Error: too many clients.\n");
 195               write (infd, "Too many clients.\n", 18);
 196               close (infd);             /* Prevent descriptor leak.. */
 197               continue;
 198             }
 199           str = fgets (string, BUFSIZ, infile);
 200           if (str == NULL)
 201             {
 202               perror_1 ("fgets");
 203               close (infd);             /* Prevent descriptor leak.. */
 204               continue;
 205             }
 206           openfiles[infd] = infile;
 207           printf ("Client: %d %s", infd, string);
 208           /* If what we read did not end in a newline,
 209              it means there is more.  Keep reading from the socket
 210              and outputting to Emacs, until we get the newline.  */
 211           while (string[strlen (string) - 1] != '\n')
 212             {
 213               if (fgets (string, BUFSIZ, infile) == 0)
 214                 break;
 215               printf ("%s", string);
 216             }
 217           fflush (stdout);
 218           fflush (infile);
 219           continue;
 220         }
 221       else if (FD_ISSET (0, &rmask)) /* emacs sends codeword, fd, and string message */
 222         {
 223           /* Read command codeword and fd */
 224           clearerr (stdin);
 225           scanf ("%s %d%*c", code, &infd);
 226           if (ferror (stdin) || feof (stdin))
 227             fatal_error ("server: error reading from standard input\n");
 228
 229           /* Transfer text from Emacs to the client, up to a newline.  */
 230           infile = openfiles[infd];
 231           while (1)
 232             {
 233               if (fgets (string, BUFSIZ, stdin) == 0)
 234                 break;
 235               fprintf (infile, "%s", string);
 236               if (string[strlen (string) - 1] == '\n')
 237                 break;
 238             }
 239           fflush (infile);
 240
 241           /* If command is close, close connection to client.  */
 242           if (strncmp (code, "Close:", 6) == 0)
 243             if (infd > 2)
 244               {
 245                 fclose (infile);
 246                 close (infd);
 247               }
 248           continue;
 249         }
 250     }
 251 }
 252
 253 #else  /* This is the SYSV IPC section */
 254
 255 #include <sys/types.h>
 256 #include <sys/signal.h>
 257 #include <sys/ipc.h>
 258 #include <sys/msg.h>
 259 #include <setjmp.h>
 260 #include <errno.h>
 261 #include <sys/utsname.h>
 262
 263 struct utsname system_name;
 264
 265 #ifndef errno
 266 extern int errno;
 267 #endif
 268
 269 jmp_buf msgenv;
 270
 271 SIGTYPE
 272 msgcatch ()
 273 {
 274   longjmp (msgenv, 1);
 275 }
 276
 277
 278 /* "THIS has to be fixed.  Remember, stderr may not exist...-rlk."
 279    Incorrect.  This program runs as an inferior of Emacs.
 280    Its stderr always exists--rms.  */
 281 #include <stdio.h>
 282
 283 main ()
 284 {
 285   int s, infd, fromlen, ioproc;
 286   key_t key;
 287   struct msgbuf * msgp =
 288     (struct msgbuf *) malloc (sizeof *msgp + BUFSIZ);
 289   struct msqid_ds msg_st;
 290   int p;
 291   char *homedir, *getenv ();
 292   char string[BUFSIZ];
 293   FILE *infile;
 294
 295   /*
 296    * Create a message queue using ~/.emacs-server as the path for ftok
 297    */
 298   if ((homedir = getenv ("HOME")) == NULL)
 299     fatal_error ("No home directory\n");
 300
 301   strcpy (string, homedir);
 302 #ifndef HAVE_LONG_FILE_NAMES
 303   /* If file names are short, we can't fit the host name.  */
 304   strcat (string, "/.emacs-server");
 305 #else
 306   strcat (string, "/.emacs-server-");
 307   uname (&system_name);
 308   strcat (string, system_name.nodename);
 309 #endif
 310   creat (string, 0600);
 311   key = ftok (string, 1);       /* unlikely to be anyone else using it */
 312   s = msgget (key, 0600 | IPC_CREAT);
 313   if (s == -1)
 314     {
 315       perror_1 ("msgget");
 316       exit (1);
 317     }
 318
 319   /* Fork so we can close connection even if parent dies */
 320   p = fork ();
 321   if (setjmp (msgenv))
 322     {
 323       msgctl (s, IPC_RMID, 0);
 324       if (p > 0)
 325         kill (p, SIGKILL);
 326       exit (0);
 327     }
 328   signal (SIGTERM, msgcatch);
 329   signal (SIGINT, msgcatch);
 330   signal (SIGHUP, msgcatch);
 331   if (p > 0)
 332     {
 333       /* This is executed in the original process that did the fork above.  */
 334       /* Get pid of Emacs itself.  */
 335       p = getppid ();
 336       setpgrp ();               /* Gnu kills process group on exit */
 337       while (1)
 338         {
 339           /* Is Emacs still alive?  */
 340           if (kill (p, 0) < 0)
 341             {
 342               msgctl (s, IPC_RMID, 0);
 343               exit (0);
 344             }
 345           sleep (10);
 346         }
 347     }
 348
 349   /* This is executed in the child made by forking above.
 350      Call it c1.  Make another process, ioproc.  */
 351
 352   ioproc = fork ();
 353   if (ioproc == 0)
 354     {
 355       /* In process ioproc, wait for text from Emacs,
 356          and send it to the process c1.
 357          This way, c1 only has to wait for one source of input.  */
 358       while (fgets (msgp->mtext, BUFSIZ, stdin))
 359         {
 360           msgp->mtype = 1;
 361           msgsnd (s, msgp, strlen (msgp->mtext) + 1, 0);
 362         }
 363       exit (1);
 364     }
 365
 366   /* In the process c1,
 367      listen for messages from clients and pass them to Emacs.  */
 368   while (1)
 369     {
 370       if ((fromlen = msgrcv (s, msgp, BUFSIZ - 1, 1, 0)) < 0)
 371         {
 372 #ifdef EINTR
 373           if (errno == EINTR)
 374             continue;
 375 #endif
 376           perror_1 ("msgrcv");
 377           exit (1);
 378         }
 379       else
 380         {
 381           msgctl (s, IPC_STAT, &msg_st);
 382
 383           /* Distinguish whether the message came from a client, or from
 384              ioproc.  */
 385           if (msg_st.msg_lspid == ioproc)
 386             {
 387               char code[BUFSIZ];
 388               int inproc;
 389
 390               /* Message from ioproc: tell a client we are done.  */
 391               msgp->mtext[strlen (msgp->mtext)-1] = 0;
 392               sscanf (msgp->mtext, "%s %d", code, &inproc);
 393               msgp->mtype = inproc;
 394               msgsnd (s, msgp, strlen (msgp->mtext) + 1, 0);
 395               continue;
 396             }
 397
 398           /* This is a request from a client: copy to stdout
 399              so that Emacs will get it.  Include msg_lspid
 400              so server.el can tell us where to send the reply.  */
 401           strncpy (string, msgp->mtext, fromlen);
 402           string[fromlen] = 0;  /* make sure */
 403           /* Newline is part of string.. */
 404           printf ("Client: %d %s", msg_st.msg_lspid, string);
 405           fflush (stdout);
 406         }
 407     }
 408 }
 409
 410 #endif /* HAVE_SYSVIPC */
 411
 412 #endif /* HAVE_SOCKETS or HAVE_SYSVIPC */
 413 \f
 414 /* This is like perror but puts `Error: ' at the beginning.  */
 415
 416 perror_1 (string)
 417      char *string;
 418 {
 419   char *copy = (char *) malloc (strlen (string) + 8);
 420   if (copy == 0)
 421     fatal_error ("Virtual memory exhausted");
 422
 423   strcpy (copy, "Error: ");
 424   strcat (copy, string);
 425   perror (copy);
 426 }
 427
 428 fatal_error (string)
 429      char *string;
 430 {
 431   fprintf (stderr, "%s", "Error: ");
 432   fprintf (stderr, string);
 433   exit (1);
 434 }