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
  34
  35 #if !defined(HAVE_SOCKETS) && !defined(HAVE_SYSVIPC)
  36 #include <stdio.h>
  37
  38 main ()
  39 {
  40   fprintf (stderr, "Sorry, the Emacs server is supported only on systems\n");
  41   fprintf (stderr, "with Berkeley sockets or System V IPC.\n");
  42   exit (1);
  43 }
  44
  45 #else /* HAVE_SOCKETS or HAVE_SYSVIPC */
  46
  47 #if ! defined (HAVE_SYSVIPC)
  48 /* BSD code is very different from SYSV IPC code */
  49
  50 #include <sys/file.h>
  51 #include <sys/types.h>
  52 #include <sys/socket.h>
  53 #include <sys/signal.h>
  54 #include <sys/un.h>
  55 #include <stdio.h>
  56 #include <errno.h>
  57
  58 extern int errno;
  59
  60 main ()
  61 {
  62   char system_name[32];
  63   int s, infd, fromlen;
  64   struct sockaddr_un server, fromunix;
  65   char *homedir;
  66   char *str, string[BUFSIZ], code[BUFSIZ];
  67   FILE *infile;
  68   FILE **openfiles;
  69   int openfiles_size;
  70
  71   int geteuid ();
  72   char *getenv ();
  73
  74   openfiles_size = 20;
  75   openfiles = (FILE **) malloc (openfiles_size * sizeof (FILE *));
  76   if (openfiles == 0)
  77     abort ();
  78
  79   /*
  80    * Open up an AF_UNIX socket in this person's home directory
  81    */
  82
  83   if ((s = socket (AF_UNIX, SOCK_STREAM, 0)) < 0)
  84     {
  85       perror ("socket");
  86       exit (1);
  87     }
  88   server.sun_family = AF_UNIX;
  89 #ifndef SERVER_HOME_DIR
  90   gethostname (system_name, sizeof (system_name));
  91   sprintf (server.sun_path, "/tmp/esrv%d-%s", geteuid (), system_name);
  92
  93   if (unlink (server.sun_path) == -1 && errno != ENOENT)
  94     {
  95       perror ("unlink");
  96       exit (1);
  97     }
  98 #else
  99   if ((homedir = getenv ("HOME")) == NULL)
 100     {
 101       fprintf (stderr,"No home directory\n");
 102       exit (1);
 103     }
 104   strcpy (server.sun_path, homedir);
 105   strcat (server.sun_path, "/.emacs_server");
 106   /* Delete anyone else's old server.  */
 107   unlink (server.sun_path);
 108 #endif
 109
 110   if (bind (s, &server, strlen (server.sun_path) + 2) < 0)
 111     {
 112       perror ("bind");
 113       exit (1);
 114     }
 115   /* Only this user can send commands to this Emacs.  */
 116   chmod (server.sun_path, 0600);
 117   /*
 118    * Now, just wait for everything to come in..
 119    */
 120   if (listen (s, 5) < 0)
 121     {
 122       perror ("listen");
 123       exit (1);
 124     }
 125
 126   /* Disable sigpipes in case luser kills client... */
 127   signal (SIGPIPE, SIG_IGN);
 128   for (;;)
 129     {
 130       int rmask = (1 << s) + 1;
 131       if (select (s + 1, &rmask, 0, 0, 0) < 0)
 132         perror ("select");
 133       if (rmask & (1 << s))     /* client sends list of filenames */
 134         {
 135           fromlen = sizeof (fromunix);
 136           fromunix.sun_family = AF_UNIX;
 137           infd = accept (s, &fromunix, &fromlen); /* open socket fd */
 138           if (infd < 0)
 139             {
 140               if (errno == EMFILE || errno == ENFILE)
 141                 printf ("Too many clients.\n");
 142               else
 143                 perror ("accept");
 144               continue;
 145             }
 146
 147           if (infd >= openfiles_size)
 148             {
 149               openfiles_size *= 2;
 150               openfiles = (FILE **) realloc (openfiles,
 151                                              openfiles_size * sizeof (FILE *));
 152               if (openfiles == 0)
 153                 abort ();
 154             }
 155
 156           infile = fdopen (infd, "r+"); /* open stream */
 157           if (infile == NULL)
 158             {
 159               printf ("Too many clients.\n");
 160               write (infd, "Too many clients.\n", 18);
 161               close (infd);             /* Prevent descriptor leak.. */
 162               continue;
 163             }
 164           str = fgets (string, BUFSIZ, infile);
 165           if (str == NULL)
 166             {
 167               perror ("fgets");
 168               close (infd);             /* Prevent descriptor leak.. */
 169               continue;
 170             }
 171           openfiles[infd] = infile;
 172           printf ("Client: %d %s", infd, string);
 173           /* If what we read did not end in a newline,
 174              it means there is more.  Keep reading from the socket
 175              and outputting to Emacs, until we get the newline.  */
 176           while (string[strlen (string) - 1] != '\n')
 177             {
 178               if (fgets (string, BUFSIZ, infile) == 0)
 179                 break;
 180               printf ("%s", string);
 181             }
 182           fflush (stdout);
 183           fflush (infile);
 184           continue;
 185         }
 186       else if (rmask & 1) /* emacs sends codeword, fd, and string message */
 187         {
 188           /* Read command codeword and fd */
 189           clearerr (stdin);
 190           scanf ("%s %d%*c", code, &infd);
 191           if (ferror (stdin) || feof (stdin))
 192             {
 193               fprintf (stderr, "server: error reading from standard input\n");
 194               exit (1);
 195             }
 196
 197           /* Transfer text from Emacs to the client, up to a newline.  */
 198           infile = openfiles[infd];
 199           while (1)
 200             {
 201               if (fgets (string, BUFSIZ, stdin) == 0)
 202                 break;
 203               fprintf (infile, "%s", string);
 204               if (string[strlen (string) - 1] == '\n')
 205                 break;
 206             }
 207           fflush (infile);
 208
 209           /* If command is close, close connection to client.  */
 210           if (strncmp (code, "Close:", 6) == 0)
 211             if (infd > 2)
 212               {
 213                 fclose (infile);
 214                 close (infd);
 215               }
 216           continue;
 217         }
 218     }
 219 }
 220
 221 #else  /* This is the SYSV IPC section */
 222
 223 #include <sys/types.h>
 224 #include <sys/signal.h>
 225 #include <sys/ipc.h>
 226 #include <sys/msg.h>
 227 #include <setjmp.h>
 228
 229 jmp_buf msgenv;
 230
 231 SIGTYPE
 232 msgcatch ()
 233 {
 234   longjmp (msgenv, 1);
 235 }
 236
 237
 238 /* "THIS has to be fixed.  Remember, stderr may not exist...-rlk."
 239    Incorrect.  This program runs as an inferior of Emacs.
 240    Its stderr always exists--rms.  */
 241 #include <stdio.h>
 242
 243 main ()
 244 {
 245   int s, infd, fromlen;
 246   key_t key;
 247   struct msgbuf * msgp =
 248     (struct msgbuf *) malloc (sizeof *msgp + BUFSIZ);
 249   struct msqid_ds msg_st;
 250   int p;
 251   char *homedir, *getenv ();
 252   char string[BUFSIZ];
 253   FILE *infile;
 254
 255   /*
 256    * Create a message queue using ~/.emacs_server as the path for ftok
 257    */
 258   if ((homedir = getenv ("HOME")) == NULL)
 259     {
 260       fprintf (stderr,"No home directory\n");
 261       exit (1);
 262     }
 263   strcpy (string, homedir);
 264   strcat (string, "/.emacs_server");
 265   creat (string, 0600);
 266   key = ftok (string, 1);       /* unlikely to be anyone else using it */
 267   s = msgget (key, 0600 | IPC_CREAT);
 268   if (s == -1)
 269     {
 270       perror ("msgget");
 271       exit (1);
 272     }
 273
 274   /* Fork so we can close connection even if parent dies */
 275   p = fork ();
 276   if (setjmp (msgenv))
 277     {
 278       msgctl (s, IPC_RMID, 0);
 279       kill (p, SIGKILL);
 280       exit (0);
 281     }
 282   signal (SIGTERM, msgcatch);
 283   signal (SIGINT, msgcatch);
 284   /* If parent goes away, remove message box and exit */
 285   if (p == 0)
 286     {
 287       p = getppid ();
 288       setpgrp ();               /* Gnu kills process group on exit */
 289       while (1)
 290         {
 291           if (kill (p, 0) < 0)
 292             {
 293               msgctl (s, IPC_RMID, 0);
 294               exit (0);
 295             }
 296           sleep (10);
 297         }
 298     }
 299
 300   while (1)
 301     {
 302       if ((fromlen = msgrcv (s, msgp, BUFSIZ - 1, 1, 0)) < 0)
 303         {
 304           perror ("msgrcv");
 305           exit (1);
 306         }
 307       else
 308         {
 309           msgctl (s, IPC_STAT, &msg_st);
 310           strncpy (string, msgp->mtext, fromlen);
 311           string[fromlen] = 0;  /* make sure */
 312           /* Newline is part of string.. */
 313           printf ("Client: %d %s", s, string);
 314           fflush (stdout);
 315           /* Now, wait for a wakeup */
 316           fgets (msgp->mtext, BUFSIZ, stdin);
 317           msgp->mtext[strlen (msgp->mtext)-1] = 0;
 318           /*      strcpy (msgp->mtext, "done");*/
 319           msgp->mtype = msg_st.msg_lspid;
 320           msgsnd (s, msgp, strlen (msgp->mtext)+1, 0);
 321         }
 322     }
 323 }
 324
 325 #endif /* HAVE_SYSVIPC */
 326
 327 #endif /* HAVE_SOCKETS or HAVE_SYSVIPC */