[Qemu-devel] [PATCH][RESEND] Reinitialize monitor upon reconnect

[Anthony Liguori]

The attached patch will reinitialize the monitor for character devices 
that support reconnecting (tcp, telnet, unix socket, etc).  This patch 
is needed to be able to connect to the monitor in a deterministic way 
(for management tools).  I've updated the patch considerably since the 
last time I sent it.

I've changed the character devices to emit an event whenever the device 
is connected.  For devices like fd, pty, and vc this will only ever 
occur when the device is created.  For the other devices, this will 
occur on connect() or accept().  This is done with a bottom half to 
ensure that a user has a chance to register for the event before the 
event is emitted.

I've changed the monitor device to print the banner whenever the reset 
event is received.  Now all of the character devices work as they did 
before (no double banners any more).

Regards,

Anthony Liguori

diff -r e7a8022a1320 console.c
--- a/console.c Tue Jan 02 03:31:01 2007 +0000
+++ b/console.c Tue Jan 02 16:38:43 2007 -0600
@@ -1086,5 +1086,7 @@ CharDriverState *text_console_init(Displ
     s->t_attrib = s->t_attrib_default;
     text_console_resize(s);
 
+    qemu_chr_reset(chr);
+
     return chr;
 }
diff -r e7a8022a1320 monitor.c
--- a/monitor.c Tue Jan 02 03:31:01 2007 +0000
+++ b/monitor.c Tue Jan 02 16:30:07 2007 -0600
@@ -55,6 +55,7 @@ typedef struct term_cmd_t {
 } term_cmd_t;
 
 static CharDriverState *monitor_hd;
+static int hide_banner;
 
 static term_cmd_t term_cmds[];
 static term_cmd_t info_cmds[];
@@ -2402,15 +2403,24 @@ static void monitor_start_input(void)
     readline_start("(qemu) ", 0, monitor_handle_command1, NULL);
 }
 
+static void term_event(void *opaque, int event)
+{
+    if (event != CHR_EVENT_RESET)
+       return;
+
+    if (!hide_banner)
+           term_printf("QEMU %s monitor - type 'help' for more information\n",
+                       QEMU_VERSION);
+    monitor_start_input();
+}
+
 void monitor_init(CharDriverState *hd, int show_banner)
 {
     monitor_hd = hd;
-    if (show_banner) {
-        term_printf("QEMU %s monitor - type 'help' for more information\n",
-                    QEMU_VERSION);
-    }
+    hide_banner = !show_banner;
+
     qemu_chr_add_read_handler(hd, term_can_read, term_read, NULL);
-    monitor_start_input();
+    qemu_chr_add_event_handler(hd, term_event);
 }
 
 /* XXX: use threads ? */
diff -r e7a8022a1320 vl.c
--- a/vl.c      Tue Jan 02 03:31:01 2007 +0000
+++ b/vl.c      Tue Jan 02 16:43:38 2007 -0600
@@ -1050,6 +1050,23 @@ void quit_timers(void)
 /***********************************************************/
 /* character device */
 
+static void qemu_chr_reset_bh(void *opaque)
+{
+    CharDriverState *s = opaque;
+    if (s->chr_event)
+       s->chr_event(s, CHR_EVENT_RESET);
+    qemu_bh_delete(s->bh);
+    s->bh = NULL;
+}
+
+void qemu_chr_reset(CharDriverState *s)
+{
+    if (s->bh == NULL) {
+       s->bh = qemu_bh_new(qemu_chr_reset_bh, s);
+       qemu_bh_schedule(s->bh);
+    }
+}
+
 int qemu_chr_write(CharDriverState *s, const uint8_t *buf, int len)
 {
     return s->chr_write(s, buf, len);
@@ -1287,6 +1304,9 @@ static CharDriverState *qemu_chr_open_fd
     chr->opaque = s;
     chr->chr_write = fd_chr_write;
     chr->chr_add_read_handler = fd_chr_add_read_handler;
+
+    qemu_chr_reset(chr);
+
     return chr;
 }
 
@@ -1704,6 +1724,7 @@ static CharDriverState *qemu_chr_open_tt
     if (!chr)
         return NULL;
     chr->chr_ioctl = tty_serial_ioctl;
+    qemu_chr_reset(chr);
     return chr;
 }
 
@@ -1767,6 +1788,9 @@ static CharDriverState *qemu_chr_open_pp
     chr->chr_write = null_chr_write;
     chr->chr_add_read_handler = null_chr_add_read_handler;
     chr->chr_ioctl = pp_ioctl;
+
+    qemu_chr_reset(chr);
+
     return chr;
 }
 
@@ -2012,6 +2036,7 @@ static CharDriverState *qemu_chr_open_wi
         free(chr);
         return NULL;
     }
+    qemu_chr_reset(chr);
     return chr;
 }
 
@@ -2115,6 +2140,7 @@ static CharDriverState *qemu_chr_open_wi
         free(chr);
         return NULL;
     }
+    qemu_chr_reset(chr);
     return chr;
 }
 
@@ -2135,6 +2161,7 @@ static CharDriverState *qemu_chr_open_wi
     chr->opaque = s;
     chr->chr_write = win_chr_write;
     chr->chr_add_read_handler = win_chr_add_read_handler;
+    qemu_chr_reset(chr);
     return chr;
 }
     
@@ -2422,6 +2449,7 @@ static void tcp_chr_connect(void *opaque
     s->connected = 1;
     qemu_set_fd_handler2(s->fd, tcp_chr_read_poll,
                          tcp_chr_read, NULL, chr);
+    qemu_chr_reset(chr);
 }
 
 #define IACSET(x,a,b,c) x[0] = a; x[1] = b; x[2] = c;
diff -r e7a8022a1320 vl.h
--- a/vl.h      Tue Jan 02 03:31:01 2007 +0000
+++ b/vl.h      Tue Jan 02 16:35:36 2007 -0600
@@ -236,11 +236,13 @@ void qemu_del_wait_object(HANDLE handle,
 void qemu_del_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque);
 #endif
 
+typedef struct QEMUBH QEMUBH;
+
 /* character device */
 
 #define CHR_EVENT_BREAK 0 /* serial break char */
 #define CHR_EVENT_FOCUS 1 /* focus to this terminal (modal input needed) */
-
+#define CHR_EVENT_RESET 2 /* new connection established */
 
 
 #define CHR_IOCTL_SERIAL_SET_PARAMS   1
@@ -271,6 +273,7 @@ typedef struct CharDriverState {
     void (*chr_send_event)(struct CharDriverState *chr, int event);
     void (*chr_close)(struct CharDriverState *chr);
     void *opaque;
+    QEMUBH *bh;
 } CharDriverState;
 
 void qemu_chr_printf(CharDriverState *s, const char *fmt, ...);
@@ -281,6 +284,7 @@ void qemu_chr_add_read_handler(CharDrive
                                IOReadHandler *fd_read, void *opaque);
 void qemu_chr_add_event_handler(CharDriverState *s, IOEventHandler *chr_event);
 int qemu_chr_ioctl(CharDriverState *s, int cmd, void *arg);
+void qemu_chr_reset(CharDriverState *s);
 
 /* consoles */
 
@@ -489,7 +493,6 @@ void do_info_snapshots(void);
 void do_info_snapshots(void);
 
 /* bottom halves */
-typedef struct QEMUBH QEMUBH;
 typedef void QEMUBHFunc(void *opaque);
 
 QEMUBH *qemu_bh_new(QEMUBHFunc *cb, void *opaque);