Add chardev option to disable signal.

If I am using vga and serial which is stdio and hit C-c on
serial console, qemu terminates. That is annoying for me.
So make it configurable whether signal is generated when C-c is hit.

Signed-off-by: Kusanagi Kouichi <slash@ac.auone-net.jp>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

qemu-char.c

@@ -729,7 +729,7 @@ static void term_exit(void)
     fcntl(0, F_SETFL, old_fd0_flags);
 }
 
-static void term_init(void)
+static void term_init(QemuOpts *opts)
 {
     struct termios tty;
 
@@ -742,7 +742,7 @@ static void term_init(void)
     tty.c_oflag |= OPOST;
     tty.c_lflag &= ~(ECHO|ECHONL|ICANON|IEXTEN);
     /* if graphical mode, we allow Ctrl-C handling */
-    if (display_type == DT_NOGRAPHIC)
+    if (!qemu_opt_get_bool(opts, "signal", display_type != DT_NOGRAPHIC))
         tty.c_lflag &= ~ISIG;
     tty.c_cflag &= ~(CSIZE|PARENB);
     tty.c_cflag |= CS8;
@@ -775,7 +775,7 @@ static CharDriverState *qemu_chr_open_stdio(QemuOpts *opts)
     chr->chr_close = qemu_chr_close_stdio;
     qemu_set_fd_handler2(0, stdio_read_poll, stdio_read, NULL, chr);
     stdio_nb_clients++;
-    term_init();
+    term_init(opts);
 
     return chr;
 }

qemu-config.c

@@ -134,6 +134,9 @@ QemuOptsList qemu_chardev_opts = {
         },{
             .name = "mux",
             .type = QEMU_OPT_BOOL,
+        },{
+            .name = "signal",
+            .type = QEMU_OPT_BOOL,
         },
         { /* end if list */ }
     },