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