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1instance.c

+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <string.h>
+#include <unistd.h>
+
+typedef struct {
+  char* filename; /* this file is the pipe (set by user) */
+  char is_server; /* this is set by open_control_file */
+  int fd; /* this is set by open_control_file */
+} single_instance_struct;
+
+/* returns fd, is_server is set to -1 if server, 0 if client */
+int open_control_file(single_instance_struct* str)
+{
+  struct stat buf;
+
+  if(stat(str->filename,&buf)) {
+    mkfifo(str->filename,128|256);
+    str->is_server=-1;
+    str->fd=open(str->filename,O_NONBLOCK|O_RDONLY);
+  } else {
+    str->fd=open(str->filename,O_NONBLOCK|O_WRONLY);
+    if(errno==ENXIO) {
+      str->is_server=-1;
+      str->fd=open(str->filename,O_NONBLOCK|O_RDONLY);
+    } else
+      str->is_server=0;
+  }
+
+  return(str->fd);
+}
+
+void delete_control_file(single_instance_struct* str)
+{
+  remove(str->filename);
+}
+
+void close_control_file(single_instance_struct* str)
+{
+  close(str->fd);
+}
+
+typedef void (*event_dispatcher)(char* message);
+
+int get_next_message(char* buffer,int len,single_instance_struct* str,int usecs)
+{
+  struct timeval tv;
+  fd_set fdset;
+  int num_fds;
+
+  FD_ZERO(&fdset);
+  FD_SET(str->fd,&fdset);
+  tv.tv_sec=0;
+  tv.tv_usec=usecs;
+
+  num_fds=select(str->fd+1,&fdset,NULL,NULL,&tv);
+  if(num_fds) {
+    int reallen;
+
+    reallen=read(str->fd,buffer,len);
+    if(reallen==0) {
+      close(str->fd);
+      str->fd=open(str->filename,O_NONBLOCK|O_RDONLY);
+      num_fds--;
+    }
+    buffer[reallen]=0;
+#ifdef DEBUG_1INSTANCE
+    if(reallen!=0) fprintf(stderr,"message received: %s.\n",buffer);
+#endif
+  }
+
+  return(num_fds);
+}
+
+int dispatch_event(single_instance_struct* str,event_dispatcher dispatcher,int usecs)
+{
+  char buffer[1024];
+  int num_fds;
+
+  if((num_fds=get_next_message(buffer,1024,str,usecs)) && buffer[0])
+    dispatcher(buffer);
+
+  return(num_fds);
+}
+
+int loop_if_server(single_instance_struct* str,event_dispatcher dispatcher)
+{
+  open_control_file(str);
+  if(str->is_server) {
+    while(1)
+      dispatch_event(str,dispatcher,50);
+  }
+
+  return(str->fd);
+}
+
+void send_message(single_instance_struct* str,char* message)
+{
+  int i=
+  write(str->fd,message,strlen(message));
+#ifdef DEBUG_1INSTANCE
+  fprintf(stderr,"send: %s => %d(%d)\n",message,i,strlen(message));
+#endif
+}
+
+#ifdef DEBUG_MAIN
+
+#include <stdio.h>
+#include <stdlib.h>
+
+single_instance_struct str1 = { "/tmp/1instance" };
+
+void my_dispatcher(char* message)
+{
+#ifdef DEBUG_1INSTANCE
+  fprintf(stderr,"Message arrived: %s.\n",message);
+#endif
+  if(!strcmp(message,"quit")) {
+    delete_control_file(str1);
+    exit(0);
+  }
+}
+
+int main(int argc,char** argv)
+{
+  int i;
+
+  loop_if_server(str1,my_dispatcher);
+
+  for(i=1;i<argc;i++)
+    send_event(str1,argv[i]);
+
+  return(0);
+}
+
+#endif

x11vnc.c

-/* This file is part of LibVNCServer.
+/* This file (x11vnc.c) is part of LibVNCServer.
    It is a small clone of x0rfbserver by HexoNet, demonstrating the
    capabilities of LibVNCServer.
 */
@@ -65,6 +65,10 @@ void newClient(rfbClientPtr cl)
 {
   if(disconnectAfterFirstClient)
     cl->clientGoneHook = clientGone;
+  if(viewOnly)
+    cl->clientData = (void*)-1;
+  else
+    cl->clientData = (void*)0;
 }
 
 #define LEFTSHIFT 1
@@ -95,6 +99,8 @@ void tweakModifiers(char mod,Bool down)
 
 void keyboard(Bool down,KeySym keySym,rfbClientPtr cl)
 {
+  if(((int)cl->clientData)==-1) return; /* viewOnly */
+
 #define ADJUSTMOD(sym,state) \
   if(keySym==sym) { if(down) ModifierState|=state; else ModifierState&=~state; }
 
@@ -132,6 +138,8 @@ void mouse(int buttonMask,int x,int y,rfbClientPtr cl)
 {
   int i=0;
 
+  if(((int)cl->clientData)==-1) return; /* viewOnly */
+
   XTestFakeMotionEvent(dpy,0,x,y,CurrentTime );
   while(i<5) {
     if ((oldButtonMask&(1<<i))!=(buttonMask&(1<<i)))
@@ -271,6 +279,12 @@ void probeScreen(rfbScreenInfoPtr s,int xscreen)
     }
 }
 
+#define LOCAL_CONTROL
+
+#ifdef LOCAL_CONTROL
+#include "1instance.c"
+#endif
+
 /* the main program */
 
 int main(int argc,char** argv)
@@ -284,7 +298,25 @@ int main(int argc,char** argv)
   int maxMsecsToConnect = 5000; /* a maximum of 5 seconds to connect */
   int updateCounter; /* about every 50 ms a screen update should be made. */
 
+#ifdef LOCAL_CONTROL
+  char message[1024];
+  single_instance_struct single_instance = { "/tmp/x11vnc_control" };
+
+  open_control_file(&single_instance);
+#endif
+
   for(i=argc-1;i>0;i--)
+#ifdef LOCAL_CONTROL
+    if(i<argc-1 && !strcmp(argv[i],"-toggleviewonly")) {
+      sprintf(message,"t%s",argv[i+1]);
+      send_message(&single_instance,message);
+      exit(0);
+    } else if(!strcmp(argv[i],"-listclients")) {
+      fprintf(stderr,"list clients\n");
+      send_message(&single_instance,"l");
+      exit(0);
+    } else
+#endif
     if(i<argc-1 && strcmp(argv[i],"-display")==0) {
       fprintf(stderr,"Using display %s\n",argv[i+1]);
       dpy = XOpenDisplay(argv[i+1]);
@@ -387,10 +419,9 @@ int main(int argc,char** argv)
   screen->cursor = 0;
   screen->newClientHook = newClient;
 
-  if(!viewOnly) {
   screen->kbdAddEvent = keyboard;
   screen->ptrAddEvent = mouse;
-  }
+
   if(sharedMode) {
     screen->rfbAlwaysShared = TRUE;
   }
@@ -413,6 +444,24 @@ int main(int argc,char** argv)
       }
     }
 
+#ifdef LOCAL_CONTROL
+    if(get_next_message(message,1024,&single_instance,50)) {
+      if(message[0]=='l' && message[1]==0) {
+	rfbClientPtr cl;
+	int i;
+	for(i=0,cl=screen->rfbClientHead;cl;cl=cl->next,i++)
+	  fprintf(stderr,"%02d: %s\n",i,cl->host);
+      } else if(message[0]=='t') {
+	rfbClientPtr cl;
+	for(cl=screen->rfbClientHead;cl;cl=cl->next)
+	  if(!strcmp(message+1,cl->host)) {
+	    cl->clientData=(cl->clientData==0)?-1:0;
+	    break;
+	  }
+      }
+    }
+#endif
+
     rfbProcessEvents(screen,-1);
 
     if(dontTile) {