ioemu: Close file descriptors when forking processes.

Just leave stdin/stdout/stderr (and possibly tap fd) open.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>

tools/ioemu/vl.c

@@ -3250,6 +3250,14 @@ static int net_tap_init(VLANState *vlan, const char *ifname1,
         pid = fork();
         if (pid >= 0) {
             if (pid == 0) {
+                int open_max = sysconf(_SC_OPEN_MAX), i;
+                for (i = 0; i < open_max; i++)
+                    if (i != STDIN_FILENO &&
+                        i != STDOUT_FILENO &&
+                        i != STDERR_FILENO &&
+                        i != fd)
+                        close(i);
+
                 parg = args;
                 *parg++ = (char *)setup_script;
                 *parg++ = ifname;

tools/ioemu/vnc.c

@@ -1445,7 +1445,7 @@ int vnc_display_init(DisplayState *ds, int display, int find_unused, struct sock
 
 int vnc_start_viewer(int port)
 {
-    int pid;
+    int pid, i, open_max;
     char s[16];
 
     sprintf(s, ":%d", port);
@@ -1456,6 +1456,12 @@ int vnc_start_viewer(int port)
 	exit(1);
 
     case 0:	/* child */
+	open_max = sysconf(_SC_OPEN_MAX);
+	for (i = 0; i < open_max; i++)
+	    if (i != STDIN_FILENO &&
+		i != STDOUT_FILENO &&
+		i != STDERR_FILENO)
+		close(i);
 	execlp("vncviewer", "vncviewer", s, NULL);
 	fprintf(stderr, "vncviewer execlp failed\n");
 	exit(1);