code.delx.au - gnu-emacs/blob - lib-src/emacsserver.c

   1 /* Communication subprocess for GNU Emacs acting as server.
   2    Copyright (C) 1986, 1987, 1992 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, 675 Mass Ave, Cambridge, MA 02139, USA.  */
  19
  20
  21 /* The GNU Emacs edit server process is run as a subprocess of Emacs
  22    under control of the file lisp/server.el.
  23    This program accepts communication from client (program emacsclient.c)
  24    and passes their commands (consisting of keyboard characters)
  25    up to the Emacs which then executes them.  */
  26
  27 #define NO_SHORTNAMES
  28 #include <../src/config.h>
  29 #undef read
  30 #undef write
  31 #undef open
  32 #undef close
  33 #undef signal
  34
  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_SYSVIPC)
  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
  59 extern int errno;
  60
  61 main ()
  62 {
  63   char system_name[32];
  64   int s, infd, fromlen;
  65   struct sockaddr_un server, fromunix;
  66   char *homedir;
  67   char *str, string[BUFSIZ], code[BUFSIZ];
  68   FILE *infile;
  69   FILE **openfiles;
  70   int openfiles_size;
  71
  72 #ifndef convex
  73   char *getenv ();
  74 #endif
  75
  76   openfiles_size = 20;
  77   openfiles = (FILE **) malloc (openfiles_size * sizeof (FILE *));
  78   if (openfiles == 0)
  79     abort ();
  80
  81   /*
  82    * Open up an AF_UNIX socket in this person's home directory
  83    */
  84
  85   if ((s = socket (AF_UNIX, SOCK_STREAM, 0)) < 0)
  86     {
  87       perror ("socket");
  88       exit (1);
  89     }
  90   server.sun_family = AF_UNIX;
  91 #ifndef SERVER_HOME_DIR
  92   gethostname (system_name, sizeof (system_name));
  93   sprintf (server.sun_path, "/tmp/esrv%d-%s", geteuid (), system_name);
  94
  95   if (unlink (server.sun_path) == -1 && errno != ENOENT)
  96     {
  97       perror ("unlink");
  98       exit (1);
  99     }
 100 #else
 101   if ((homedir = getenv ("HOME")) == NULL)
 102     {
 103       fprintf (stderr,"No home directory\n");
 104       exit (1);
 105     }
 106   strcpy (server.sun_path, homedir);
 107   strcat (server.sun_path, "/.emacs_server");
 108   /* Delete anyone else's old server.  */
 109   unlink (server.sun_path);
 110 #endif
 111
 112   if (bind (s, (struct sockaddr *) &server, strlen (server.sun_path) + 2) < 0)
 113     {
 114       perror ("bind");
 115       exit (1);
 116     }
 117   /* Only this user can send commands to this Emacs.  */
 118   chmod (server.sun_path, 0600);
 119   /*
 120    * Now, just wait for everything to come in..
 121    */
 122   if (listen (s, 5) < 0)
 123     {
 124       perror ("listen");
 125       exit (1);
 126     }
 127
 128   /* Disable sigpipes in case luser kills client... */
 129   signal (SIGPIPE, SIG_IGN);
 130   for (;;)
 131     {
 132       int rmask = (1 << s) + 1;
 133       if (select (s + 1, &rmask, 0, 0, 0) < 0)
 134         perror ("select");
 135       if (rmask & (1 << s))     /* client sends list of filenames */
 136         {
 137           fromlen = sizeof (fromunix);
 138           fromunix.sun_family = AF_UNIX;
 139           infd = accept (s, (struct sockaddr *) &fromunix, &fromlen); /* open socket fd */
 140           if (infd < 0)
 141             {
 142               if (errno == EMFILE || errno == ENFILE)
 143                 printf ("Too many clients.\n");
 144               else
 145                 perror ("accept");
 146               continue;
 147             }
 148
 149           if (infd >= openfiles_size)
 150             {
 151               openfiles_size *= 2;
 152               openfiles = (FILE **) realloc (openfiles,
 153                                              openfiles_size * sizeof (FILE *));
 154               if (openfiles == 0)
 155                 abort ();
 156             }
 157
 158           infile = fdopen (infd, "r+"); /* open stream */
 159           if (infile == NULL)
 160             {
 161               printf ("Too many clients.\n");
 162               write (infd, "Too many clients.\n", 18);
 163               close (infd);             /* Prevent descriptor leak.. */
 164               continue;
 165             }
 166           str = fgets (string, BUFSIZ, infile);
 167           if (str == NULL)
 168             {
 169               perror ("fgets");
 170               close (infd);             /* Prevent descriptor leak.. */
 171               continue;
 172             }
 173           openfiles[infd] = infile;
 174           printf ("Client: %d %s", infd, string);
 175           /* If what we read did not end in a newline,
 176              it means there is more.  Keep reading from the socket
 177              and outputting to Emacs, until we get the newline.  */
 178           while (string[strlen (string) - 1] != '\n')
 179             {
 180               if (fgets (string, BUFSIZ, infile) == 0)
 181                 break;
 182               printf ("%s", string);
 183             }
 184           fflush (stdout);
 185           fflush (infile);
 186           continue;
 187         }
 188       else if (rmask & 1) /* emacs sends codeword, fd, and string message */
 189         {
 190           /* Read command codeword and fd */
 191           clearerr (stdin);
 192           scanf ("%s %d%*c", code, &infd);
 193           if (ferror (stdin) || feof (stdin))
 194             {
 195               fprintf (stderr, "server: error reading from standard input\n");
 196               exit (1);
 197             }
 198
 199           /* Transfer text from Emacs to the client, up to a newline.  */
 200           infile = openfiles[infd];
 201           while (1)
 202             {
 203               if (fgets (string, BUFSIZ, stdin) == 0)
 204                 break;
 205               fprintf (infile, "%s", string);
 206               if (string[strlen (string) - 1] == '\n')
 207                 break;
 208             }
 209           fflush (infile);
 210
 211           /* If command is close, close connection to client.  */
 212           if (strncmp (code, "Close:", 6) == 0)
 213             if (infd > 2)
 214               {
 215                 fclose (infile);
 216                 close (infd);
 217               }
 218           continue;
 219         }
 220     }
 221 }
 222
 223 #else  /* This is the SYSV IPC section */
 224
 225 #include <sys/types.h>
 226 #include <sys/signal.h>
 227 #include <sys/ipc.h>
 228 #include <sys/msg.h>
 229 #include <setjmp.h>
 230
 231 jmp_buf msgenv;
 232
 233 SIGTYPE
 234 msgcatch ()
 235 {
 236   longjmp (msgenv, 1);
 237 }
 238
 239
 240 /* "THIS has to be fixed.  Remember, stderr may not exist...-rlk."
 241    Incorrect.  This program runs as an inferior of Emacs.
 242    Its stderr always exists--rms.  */
 243 #include <stdio.h>
 244
 245 main ()
 246 {
 247   int s, infd, fromlen;
 248   key_t key;
 249   struct msgbuf * msgp =
 250     (struct msgbuf *) malloc (sizeof *msgp + BUFSIZ);
 251   struct msqid_ds msg_st;
 252   int p;
 253   char *homedir, *getenv ();
 254   char string[BUFSIZ];
 255   FILE *infile;
 256
 257   /*
 258    * Create a message queue using ~/.emacs_server as the path for ftok
 259    */
 260   if ((homedir = getenv ("HOME")) == NULL)
 261     {
 262       fprintf (stderr,"No home directory\n");
 263       exit (1);
 264     }
 265   strcpy (string, homedir);
 266   strcat (string, "/.emacs_server");
 267   creat (string, 0600);
 268   key = ftok (string, 1);       /* unlikely to be anyone else using it */
 269   s = msgget (key, 0600 | IPC_CREAT);
 270   if (s == -1)
 271     {
 272       perror ("msgget");
 273       exit (1);
 274     }
 275
 276   /* Fork so we can close connection even if parent dies */
 277   p = fork ();
 278   if (setjmp (msgenv))
 279     {
 280       msgctl (s, IPC_RMID, 0);
 281       kill (p, SIGKILL);
 282       exit (0);
 283     }
 284   signal (SIGTERM, msgcatch);
 285   signal (SIGINT, msgcatch);
 286   if (p > 0)
 287     {
 288       /* This is executed in the original process that did the fork above.  */
 289       /* Get pid of Emacs itself.  */
 290       p = getppid ();
 291       setpgrp ();               /* Gnu kills process group on exit */
 292       while (1)
 293         {
 294           /* Is Emacs still alive?  */
 295           if (kill (p, 0) < 0)
 296             {
 297               msgctl (s, IPC_RMID, 0);
 298               exit (0);
 299             }
 300           sleep (10);
 301         }
 302     }
 303
 304   /* This is executed in the child made by forking above.  */
 305   while (1)
 306     {
 307       if ((fromlen = msgrcv (s, msgp, BUFSIZ - 1, 1, 0)) < 0)
 308         {
 309           perror ("msgrcv");
 310           exit (1);
 311         }
 312       else
 313         {
 314           msgctl (s, IPC_STAT, &msg_st);
 315           strncpy (string, msgp->mtext, fromlen);
 316           string[fromlen] = 0;  /* make sure */
 317           /* Newline is part of string.. */
 318           printf ("Client: %d %s", s, string);
 319           fflush (stdout);
 320           /* Now, wait for a wakeup */
 321           fgets (msgp->mtext, BUFSIZ, stdin);
 322           msgp->mtext[strlen (msgp->mtext)-1] = 0;
 323           /*      strcpy (msgp->mtext, "done");*/
 324           msgp->mtype = msg_st.msg_lspid;
 325           msgsnd (s, msgp, strlen (msgp->mtext)+1, 0);
 326         }
 327     }
 328 }
 329
 330 #endif /* HAVE_SYSVIPC */
 331
 332 #endif /* HAVE_SOCKETS or HAVE_SYSVIPC */