/* -*-C-*- Server code for handling requests from clients and forwarding them on to the GNU Emacs process. This file is part of GNU Emacs. Copying is permitted under those conditions described by the GNU General Public License. Copyright (C) 1989 Free Software Foundation, Inc. Author: Andy Norman (ange@hplb.hpl.hp.com), based on 'etc/server.c'         from the 18.52 GNU Emacs distribution. Please mail bugs and suggestions to the author at the above address.*//* HISTORY  * 11-Nov-1990		bristor@simba	 *    Added EOT stuff. *//* * This file incorporates new features added by Bob Weiner <weiner@mot.com>, * Darrell Kindred <dkindred@cmu.edu> and Arup Mukherjee <arup@cmu.edu>. * Please see the note at the end of the README file for details. * * (If gnuserv came bundled with your emacs, the README file is probably * ../etc/gnuserv.README relative to the directory containing this file) */static char rcsid [] = "$Header: gnuserv.c,v 2.0 94/08/14 12:33:29 arup Exp $";#include "gnuserv.h"#ifdef USE_LITOUT#ifdef linux#include <bsd/sgtty.h>#else#include <sgtty.h>#endif#endif#ifdef AIX#include <sys/select.h>#endif#if !defined(SYSV_IPC) && !defined(UNIX_DOMAIN_SOCKETS) && \    !defined(INTERNET_DOMAIN_SOCKETS)main (){  fprintf (stderr,"Sorry, the Emacs server is only supported on systems that have\n");  fprintf (stderr,"Unix Domain sockets, Internet Domain sockets or System V IPC\n");  exit (1);} /* main */#else /* SYSV_IPC || UNIX_DOMAIN_SOCKETS || INTERNET_DOMAIN_SOCKETS */#ifdef SYSV_IPCint ipc_qid = 0;		/* ipc message queue id */int ipc_wpid = 0;		/* watchdog task pid *//*  ipc_exit -- clean up the queue id and queue, then kill the watchdog task              if it exists. exit with the given status.*/void ipc_exit(stat)     int stat;{  msgctl(ipc_qid,IPC_RMID,0);    if (ipc_wpid != 0)    kill(ipc_wpid,SIGKILL);  exit(stat);} /* ipc_exit *//*  ipc_handle_signal -- catch the signal given and clean up.*/void ipc_handle_signal(sig)     int sig;{  ipc_exit(0);} /* ipc_handle_signal *//*   ipc_spawn_watchdog -- spawn a watchdog task to clean up the message queue should the			server process die.*/int ipc_spawn_watchdog(){  if ((ipc_wpid = fork()) == 0) { /* child process */    int ppid = getppid();	/* parent's process id */    setpgrp();			/* gnu kills process group on exit */        while (1) {      if (kill(ppid,0) < 0) {	/* ppid is no longer valid, parent may have died */	ipc_exit(0);      }; /* if */      sleep(10);		/* have another go later */    }; /* while */  }; /* if */} /* ipc_spawn_watchdog *//*  ipc_init -- initialize server, setting the global msqid that can be listened on.*/void ipc_init(msgpp)     struct msgbuf **msgpp;{  key_t key;			/* messge key */  char buf[GSERV_BUFSZ];	/* pathname for key */  int p;			/* child process id */  sprintf(buf,"/tmp/gsrv%d",geteuid());  creat(buf,0600);  key = ftok(buf,1);  if ((ipc_qid = msgget(key,0600|IPC_CREAT)) == -1) {    perror(progname);    fprintf(stderr,"%s: unable to create msg queue\n",progname);    ipc_exit(1);  }; /* if */  ipc_spawn_watchdog();  signal(SIGTERM,ipc_handle_signal);  signal(SIGINT,ipc_handle_signal);  if ((*msgpp = (struct msgbuf *)                 malloc(sizeof **msgpp + GSERV_BUFSZ)) == NULL) {    fprintf(stderr,	    "%s: unable to allocate space for message buffer\n",progname);    ipc_exit(1);  }; /* if */} /* ipc_init *//*  handle_ipc_request -- accept a request from a client, pass the request on  			to the GNU Emacs process, then wait for its reply and			pass that on to the client.*/void handle_ipc_request(msgp)     struct msgbuf *msgp;	/* message buffer */{  struct msqid_ds msg_st;	/* message status */  char buf[GSERV_BUFSZ];  int len;			/* length of message / read */  int s, result_len;            /* tag fields on the response from emacs */  int junk;			/* junk value */  int offset = 0;  int total = 1;                /* # bytes that will actually be sent off */  if ((len = msgrcv(ipc_qid,msgp,GSERV_BUFSZ-1,1,0)) < 0) {    perror(progname);    fprintf(stderr,"%s: unable to receive\n",progname);    ipc_exit(1);  }; /* if */  msgctl(ipc_qid,IPC_STAT,&msg_st);  strncpy(buf,msgp->mtext,len);  buf[len] = '\0';		/* terminate */    printf("%d %s",ipc_qid,buf);  fflush(stdout);  /* now for the response from gnu */  msgp->mtext[0] = '\0';#if 0  if ((len = read(0,buf,GSERV_BUFSZ)) < 0) {    perror(progname);    fprintf(stderr,"%s: unable to read\n",progname);    ipc_exit(1);  }; /* if */        sscanf(buf,"%d:%[^\n]\n",&junk,msgp->mtext);#else   /* read in "n/m:" (n=client fd, m=message length) */  while (offset < GSERV_BUFSZ && 	 ((len = read(0,buf+offset,1)) > 0) &&	 buf[offset] != ':') {    offset += len;  }  if (len < 0) {    perror(progname);    fprintf(stderr,"%s: unable to read\n",progname);    exit(1);  }        /* parse the response from emacs, getting client fd & result length */  buf[offset] = '\0';  sscanf(buf,"%d/%d", &s, &result_len);  while (result_len > 0) {    if ((len = read(0,buf,min2(result_len, GSERV_BUFSZ - 1))) < 0) {      perror(progname);      fprintf(stderr,"%s: unable to read\n",progname);      exit(1);    }    /* Send this string off, but only if we have enough space */     if (GSERV_BUFSZ > total) {      if (total + len <= GSERV_BUFSZ)	buf[len] = 0;      else 	buf[GSERV_BUFSZ - total] = 0;      send_string(s,buf);      total += strlen(buf);    };    result_len -= len;  }  /* eat the newline */  while ((len = read(0,buf,1)) == 0)    ;  if (len < 0) {    perror(progname);    fprintf(stderr,"%s: unable to read\n",progname);    exit(1);  }  if (buf[0] != '\n') {    fprintf(stderr,"%s: garbage after result [%c]\n",progname, buf[0]);    exit(1);  }#endif  /* Send a response back to the client. */  msgp->mtype = msg_st.msg_lspid;  if (msgsnd(ipc_qid,msgp,strlen(msgp->mtext)+1,0) < 0)    perror("msgsend(gnuserv)");} /* handle_ipc_request */#endif /* SYSV_IPC */#if defined(INTERNET_DOMAIN_SOCKETS) || defined(UNIX_DOMAIN_SOCKETS)/*  echo_request -- read request from a given socket descriptor, and send the information                  to stdout (the gnu process).*/void echo_request(s)int s;				/* socket */{  char buf[GSERV_BUFSZ];  int len;  printf("%d ",s);    /* read until we get a newline or no characters */  while ((len = recv(s,buf,GSERV_BUFSZ,0)) > 0) {    buf[len] = '\0';    printf("%s",buf);    if (buf[len-1] == EOT_CHR) {      fflush(stdout);      break;			/* end of message */    }  }; /* while */  if (len < 0) {    perror(progname);    fprintf(stderr,"%s: unable to recv\n",progname);    exit(1);  }; /* if */  } /* echo_request *//*  handle_response -- accept a response from stdin (the gnu process) and pass the                     information on to the relevant client.*/void handle_response(){  char buf[GSERV_BUFSZ+1];  char response[GSERV_BUFSZ+1];  int offset=0;  int s;  int len;  int result_len;  /* read in "n/m:" (n=client fd, m=message length) */  while (offset < GSERV_BUFSZ && 	 ((len = read(0,buf+offset,1)) > 0) &&	 buf[offset] != ':') {    offset += len;  }  if (len < 0) {    perror(progname);    fprintf(stderr,"%s: unable to read\n",progname);    exit(1);  }        /* parse the response from emacs, getting client fd & result length */  buf[offset] = '\0';  sscanf(buf,"%d/%d", &s, &result_len);  while (result_len > 0) {    if ((len = read(0,buf,min2(result_len,GSERV_BUFSZ))) < 0) {      perror(progname);      fprintf(stderr,"%s: unable to read\n",progname);      exit(1);    }    buf[len] = '\0';    send_string(s,buf);    result_len -= len;  }  /* eat the newline */  while ((len = read(0,buf,1)) == 0)    ;  if (len < 0) {    perror(progname);    fprintf(stderr,"%s: unable to read\n",progname);    exit(1);  }  if (buf[0] != '\n') {    fprintf(stderr,"%s: garbage after result\n",progname);    exit(1);  }  close(s);} /* handle_response */#endif /* INTERNET_DOMAIN_SOCKETS || UNIX_DOMAIN_SOCKETS */#ifdef INTERNET_DOMAIN_SOCKETSstruct entry {