This is the mail archive of the
gdb-patches@sourceware.org
mailing list for the GDB project.
[PATCH 2/8] de-couple %Stop from notification: gdbserver
Hi
This patch de-couples %Stop notification out of notification
infrastructure, so that adding new notification is easier.
See details in the header comment in gdbserver/notif.c.
This version (V4) is mostly to address Pedro's comments, to do some
renaming, for example, 'struct notif' -> 'struct notif_server',
'struct notif_reply' -> 'struct notif_event'. In V4, we also move
'ptid' field out of 'struct notif_event' into its sub-class 'struct
stop_reply'.
Note that this patch doesn't rename 'vstop_notif'. We can change its
name is a separate patch if we want.
gdb/gdbserver:
2012-12-11 Yao Qi <yao@codesourcery.com>
* Makefile.in (OBS): Add notif.o.
(notif_h, queue_h): New.
(notif.o): New rule.
* notif.c, notif.h: New.
* server.c: Include "notif.h".
(struct vstop_notif) <next>: Remove.
<base>: New field.
(queue_stop_reply): Update.
(push_event, send_next_stop_reply): Remove.
(discard_queued_stop_replies): Update.
(notif_stop): New variable.
(handle_v_stopped): Remove.
(handle_v_requests): Don't call handle_v_stopped. Call
handle_ack_notif instead.
(queue_stop_reply_callback): Call notif_event_enque instead
of queue_stop_reply.
(handle_status): Don't call send_next_stop_reply, call
notif_write_event instead.
(kill_inferior_callback): Likewise.
(detach_or_kill_inferior_callback): Likewise.
(main): Call initialize_notif.
(process_serial_event): Call QUEUE_is_empty.
(handle_target_event): Call notif_push instead of push event.
* server.h: Remove declaration of push_event.
---
gdb/gdbserver/Makefile.in | 4 +-
gdb/gdbserver/notif.c | 168 +++++++++++++++++++++++++++++++++++++++++++++
gdb/gdbserver/notif.h | 66 ++++++++++++++++++
gdb/gdbserver/server.c | 164 ++++++++++++++-----------------------------
gdb/gdbserver/server.h | 2 -
5 files changed, 291 insertions(+), 113 deletions(-)
create mode 100644 gdb/gdbserver/notif.c
create mode 100644 gdb/gdbserver/notif.h
diff --git a/gdb/gdbserver/Makefile.in b/gdb/gdbserver/Makefile.in
index d7dad29..9f440cc 100644
--- a/gdb/gdbserver/Makefile.in
+++ b/gdb/gdbserver/Makefile.in
@@ -168,7 +168,7 @@ OBS = agent.o ax.o inferiors.o regcache.o remote-utils.o server.o signals.o targ
utils.o version.o vec.o gdb_vecs.o \
mem-break.o hostio.o event-loop.o tracepoint.o \
xml-utils.o common-utils.o ptid.o buffer.o format.o \
- dll.o \
+ dll.o notif.o \
$(XML_BUILTIN) \
$(DEPFILES) $(LIBOBJS)
GDBREPLAY_OBS = gdbreplay.o version.o
@@ -418,6 +418,7 @@ gdb_proc_service_h = $(srcdir)/gdb_proc_service.h
regdat_sh = $(srcdir)/../regformats/regdat.sh
regdef_h = $(srcdir)/../regformats/regdef.h
regcache_h = $(srcdir)/regcache.h
+queue_h = $(srcdir)/../common/queue.h
signals_def = $(srcdir)/../../include/gdb/signals.def
signals_h = $(srcdir)/../../include/gdb/signals.h $(signals_def)
ptid_h = $(srcdir)/../common/ptid.h
@@ -442,6 +443,7 @@ server_h = $(srcdir)/server.h $(regcache_h) $(srcdir)/target.h \
$(libiberty_h) \
$(srcdir)/../../include/ansidecl.h \
$(generated_files)
+notif_h = ${srcdir}/notif.h
gdbthread_h = $(srcdir)/gdbthread.h $(target_h) $(srcdir)/server.h
linux_low_h = $(srcdir)/linux-low.h $(gdbthread_h)
diff --git a/gdb/gdbserver/notif.c b/gdb/gdbserver/notif.c
new file mode 100644
index 0000000..0713b36
--- /dev/null
+++ b/gdb/gdbserver/notif.c
@@ -0,0 +1,168 @@
+/* Notification to GDB.
+ Copyright (C) 1989, 1993-1995, 1997-2000, 2002-2012 Free Software
+ Foundation, Inc.
+
+ This file is part of GDB.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+/* Async notifications to GDB. When the state of remote target is
+ changed or something interesting to GDB happened, async
+ notifications are used to tell GDB.
+
+ Each type of notification is represented by an object
+ 'struct notif_server', in which there is a queue for events to GDB
+ represented by 'struct notif_event'. GDBserver writes (by means of
+ 'write' field) each event in the queue into the buffer and send the
+ contents in buffer to GDB. The contents in buffer is specified in
+ RSP. See more in the comments to field 'queue' of
+ 'struct notif_server'.
+
+ Here is the workflow of sending events and managing queue:
+ 1. At any time, when something interesting FOO happens, a object
+ of 'struct notif_event' or its sub-class EVENT is created for FOO.
+
+ 2. Enque EVENT to the 'queue' field of 'struct notif_server' for
+ FOO and send corresponding notification packet to GDB if EVENT is
+ the first one.
+ #1 and #2 are done by function 'notif_push'.
+
+ 3. EVENT is not deque'ed until the ack of FOO from GDB arrives.
+ Before ack of FOO arrives, FOO happens again, a new object of
+ EVENT is created and enque EVENT silently.
+ Once GDB has a chance to ack to FOO, it sends an ack to GDBserver,
+ and GDBserver repeatedly sends events to GDB and gets ack of FOO,
+ until queue is empty. Then, GDBserver sends 'OK' to GDB that all
+ queued notification events are done.
+
+ # 3 is done by function 'handle_notif_ack'. */
+
+#include "notif.h"
+
+static struct notif_server *notifs[] =
+{
+ ¬if_stop,
+};
+
+/* Write another event or an OK, if there are no more left, to
+ OWN_BUF. */
+
+void
+notif_write_event (struct notif_server *notif, char *own_buf)
+{
+ if (!QUEUE_is_empty (notif_event_p, notif->queue))
+ {
+ struct notif_event *event
+ = QUEUE_peek (notif_event_p, notif->queue);
+
+ notif->write (event, own_buf);
+ }
+ else
+ write_ok (own_buf);
+}
+
+/* Handle the ack in buffer OWN_BUF,and packet length is PACKET_LEN.
+ Return 1 if the ack is handled, and return 0 if the contents
+ in OWN_BUF is not a ack. */
+
+int
+handle_notif_ack (char *own_buf, int packet_len)
+{
+ int i = 0;
+ struct notif_server *np = NULL;
+
+ for (i = 0; i < ARRAY_SIZE (notifs); i++)
+ {
+ np = notifs[i];
+ if (strncmp (own_buf, np->ack_name, strlen (np->ack_name)) == 0
+ && packet_len == strlen (np->ack_name))
+ break;
+ }
+
+ if (np == NULL)
+ return 0;
+
+ /* If we're waiting for GDB to acknowledge a pending event,
+ consider that done. */
+ if (!QUEUE_is_empty (notif_event_p, np->queue))
+ {
+ struct notif_event *head
+ = QUEUE_deque (notif_event_p, np->queue);
+
+ if (remote_debug)
+ fprintf (stderr, "%s: acking %d\n", np->ack_name,
+ QUEUE_length (notif_event_p, np->queue));
+
+ xfree (head);
+ }
+
+ notif_write_event (np, own_buf);
+
+ return 1;
+}
+
+/* Put EVENT to the queue of NOTIF. */
+
+void
+notif_event_enque (struct notif_server *notif,
+ struct notif_event *event)
+{
+ QUEUE_enque (notif_event_p, notif->queue, event);
+
+ if (remote_debug)
+ fprintf (stderr, "pending events: %s %d\n", notif->notif_name,
+ QUEUE_length (notif_event_p, notif->queue));
+
+}
+
+/* Push one event NEW_EVENT of notification NP into NP->queue. */
+
+void
+notif_push (struct notif_server *np, struct notif_event *new_event)
+{
+ int is_first_event = QUEUE_is_empty (notif_event_p, np->queue);
+
+ /* Something interesting. Tell GDB about it. */
+ notif_event_enque (np, new_event);
+
+ /* If this is the first stop reply in the queue, then inform GDB
+ about it, by sending a corresponding notification. */
+ if (is_first_event)
+ {
+ char buf[PBUFSIZ];
+ char *p = buf;
+
+ xsnprintf (p, PBUFSIZ, "%s:", np->notif_name);
+ p += strlen (p);
+
+ np->write (new_event, p);
+ putpkt_notif (buf);
+ }
+}
+
+static void
+notif_event_xfree (struct notif_event *event)
+{
+ xfree (event);
+}
+
+void
+initialize_notif (void)
+{
+ int i = 0;
+
+ for (i = 0; i < ARRAY_SIZE (notifs); i++)
+ notifs[i]->queue
+ = QUEUE_alloc (notif_event_p, notif_event_xfree);
+}
diff --git a/gdb/gdbserver/notif.h b/gdb/gdbserver/notif.h
new file mode 100644
index 0000000..e153b48
--- /dev/null
+++ b/gdb/gdbserver/notif.h
@@ -0,0 +1,66 @@
+/* Notification to GDB.
+ Copyright (C) 1989, 1993-1995, 1997-2000, 2002-2012 Free Software
+ Foundation, Inc.
+
+ This file is part of GDB.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+#include "ptid.h"
+#include "server.h"
+#include "target.h"
+#include "queue.h"
+
+/* Structure holding information related to a single event. We
+ keep a queue of these to push to GDB. It can be extended if
+ the event of given notification contains more information. */
+
+typedef struct notif_event
+{
+} *notif_event_p;
+
+DECLARE_QUEUE_P (notif_event_p);
+
+/* A type notification to GDB. An object of 'struct notif_server'
+ represents a type of notification. */
+
+typedef struct notif_server
+{
+ /* The name of ack packet, for example, 'vStopped'. */
+ const char *ack_name;
+
+ /* The notification packet, for example, '%Stop'. Note that '%' is
+ not in 'notif_name'. */
+ const char *notif_name;
+
+ /* A queue of events to GDB. A new notif_event can be enque'ed
+ into QUEUE at any appropriate time, and the notif_reply is
+ deque'ed only when the ack from GDB arrives. */
+ QUEUE (notif_event_p) *queue;
+
+ /* Write event EVENT to OWN_BUF. */
+ void (*write) (struct notif_event *event, char *own_buf);
+} *notif_server_p;
+
+extern struct notif_server notif_stop;
+extern struct notif notif_trace;
+
+int handle_notif_ack (char *own_buf, int packet_len);
+void notif_write_event (struct notif_server *notif, char *own_buf);
+
+void notif_push (struct notif_server *np, struct notif_event *event);
+void notif_event_enque (struct notif_server *notif,
+ struct notif_event *event);
+
+void initialize_notif (void);
diff --git a/gdb/gdbserver/server.c b/gdb/gdbserver/server.c
index fae9199..fb7322c 100644
--- a/gdb/gdbserver/server.c
+++ b/gdb/gdbserver/server.c
@@ -20,6 +20,7 @@
#include "server.h"
#include "gdbthread.h"
#include "agent.h"
+#include "notif.h"
#if HAVE_UNISTD_H
#include <unistd.h>
@@ -115,13 +116,13 @@ static ptid_t last_ptid;
static char *own_buf;
static unsigned char *mem_buf;
-/* Structure holding information relative to a single stop reply. We
- keep a queue of these (really a singly-linked list) to push to GDB
- in non-stop mode. */
+/* A sub-class of 'struct notif_event' for stop, holding information
+ relative to a single stop reply. We keep a queue of these to
+ push to GDB in non-stop mode. */
+
struct vstop_notif
{
- /* Pointer to next in list. */
- struct vstop_notif *next;
+ struct notif_event base;
/* Thread or process that got the event. */
ptid_t ptid;
@@ -130,66 +131,39 @@ struct vstop_notif
struct target_waitstatus status;
};
-/* The pending stop replies list head. */
-static struct vstop_notif *notif_queue = NULL;
+DEFINE_QUEUE_P (notif_event_p);
/* Put a stop reply to the stop reply queue. */
static void
queue_stop_reply (ptid_t ptid, struct target_waitstatus *status)
{
- struct vstop_notif *new_notif;
+ struct vstop_notif *new_notif = xmalloc (sizeof (*new_notif));
- new_notif = xmalloc (sizeof (*new_notif));
- new_notif->next = NULL;
new_notif->ptid = ptid;
new_notif->status = *status;
- if (notif_queue)
- {
- struct vstop_notif *tail;
- for (tail = notif_queue;
- tail && tail->next;
- tail = tail->next)
- ;
- tail->next = new_notif;
- }
- else
- notif_queue = new_notif;
-
- if (remote_debug)
- {
- int i = 0;
- struct vstop_notif *n;
-
- for (n = notif_queue; n; n = n->next)
- i++;
-
- fprintf (stderr, "pending stop replies: %d\n", i);
- }
+ notif_event_enque (¬if_stop, (struct notif_event *) new_notif);
}
-/* Place an event in the stop reply queue, and push a notification if
- we aren't sending one yet. */
-
-void
-push_event (ptid_t ptid, struct target_waitstatus *status)
+static int
+remove_all_on_match_pid (QUEUE (notif_event_p) *q,
+ QUEUE_ITER (notif_event_p) *iter,
+ struct notif_event *event,
+ void *data)
{
- gdb_assert (status->kind != TARGET_WAITKIND_IGNORE);
+ int *pid = data;
- queue_stop_reply (ptid, status);
-
- /* If this is the first stop reply in the queue, then inform GDB
- about it, by sending a Stop notification. */
- if (notif_queue->next == NULL)
+ if (*pid == -1
+ || ptid_get_pid (((struct vstop_notif *) event)->ptid) == *pid)
{
- char *p = own_buf;
- strcpy (p, "Stop:");
- p += strlen (p);
- prepare_resume_reply (p,
- notif_queue->ptid, ¬if_queue->status);
- putpkt_notif (own_buf);
+ if (q->free_func != NULL)
+ q->free_func (event);
+
+ QUEUE_remove_elem (notif_event_p, q, iter);
}
+
+ return 1;
}
/* Get rid of the currently pending stop replies for PID. If PID is
@@ -198,40 +172,23 @@ push_event (ptid_t ptid, struct target_waitstatus *status)
static void
discard_queued_stop_replies (int pid)
{
- struct vstop_notif *prev = NULL, *reply, *next;
-
- for (reply = notif_queue; reply; reply = next)
- {
- next = reply->next;
-
- if (pid == -1
- || ptid_get_pid (reply->ptid) == pid)
- {
- if (reply == notif_queue)
- notif_queue = next;
- else
- prev->next = reply->next;
-
- free (reply);
- }
- else
- prev = reply;
- }
+ QUEUE_iterate (notif_event_p, notif_stop.queue,
+ remove_all_on_match_pid, &pid);
}
-/* If there are more stop replies to push, push one now. */
-
static void
-send_next_stop_reply (char *own_buf)
+vstop_notif_reply (struct notif_event *event, char *own_buf)
{
- if (notif_queue)
- prepare_resume_reply (own_buf,
- notif_queue->ptid,
- ¬if_queue->status);
- else
- write_ok (own_buf);
+ struct vstop_notif *vstop = (struct vstop_notif *) event;
+
+ prepare_resume_reply (own_buf, vstop->ptid, &vstop->status);
}
+struct notif_server notif_stop =
+{
+ "vStopped", "Stop", NULL, vstop_notif_reply,
+};
+
static int
target_running (void)
{
@@ -2169,29 +2126,6 @@ handle_v_kill (char *own_buf)
}
}
-/* Handle a 'vStopped' packet. */
-static void
-handle_v_stopped (char *own_buf)
-{
- /* If we're waiting for GDB to acknowledge a pending stop reply,
- consider that done. */
- if (notif_queue)
- {
- struct vstop_notif *head;
-
- if (remote_debug)
- fprintf (stderr, "vStopped: acking %s\n",
- target_pid_to_str (notif_queue->ptid));
-
- head = notif_queue;
- notif_queue = notif_queue->next;
- free (head);
- }
-
- /* Push another stop reply, or if there are no more left, an OK. */
- send_next_stop_reply (own_buf);
-}
-
/* Handle all of the extended 'v' packets. */
void
handle_v_requests (char *own_buf, int packet_len, int *new_packet_len)
@@ -2252,11 +2186,8 @@ handle_v_requests (char *own_buf, int packet_len, int *new_packet_len)
return;
}
- if (strncmp (own_buf, "vStopped", 8) == 0)
- {
- handle_v_stopped (own_buf);
- return;
- }
+ if (handle_notif_ack (own_buf, packet_len))
+ return;
/* Otherwise we didn't know what packet it was. Say we didn't
understand it. */
@@ -2337,9 +2268,14 @@ queue_stop_reply_callback (struct inferior_list_entry *entry, void *arg)
manage the thread's last_status field. */
if (the_target->thread_stopped == NULL)
{
+ struct vstop_notif *new_notif = xmalloc (sizeof (*new_notif));
+
+ new_notif->ptid = entry->id;
+ new_notif->status = thread->last_status;
/* Pass the last stop reply back to GDB, but don't notify
yet. */
- queue_stop_reply (entry->id, &thread->last_status);
+ notif_event_enque (¬if_stop,
+ (struct notif_event *) new_notif);
}
else
{
@@ -2420,7 +2356,7 @@ handle_status (char *own_buf)
/* The first is sent immediatly. OK is sent if there is no
stopped thread, which is the same handling of the vStopped
packet (by design). */
- send_next_stop_reply (own_buf);
+ notif_write_event (¬if_stop, own_buf);
}
else
{
@@ -2789,6 +2725,8 @@ main (int argc, char *argv[])
last_ptid = minus_one_ptid;
}
+ initialize_notif ();
+
/* Don't report shared library events on the initial connection,
even if some libraries are preloaded. Avoids the "stopped by
shared library event" notice on gdb side. */
@@ -3400,7 +3338,7 @@ process_serial_event (void)
{
/* In non-stop, defer exiting until GDB had a chance to query
the whole vStopped list (until it gets an OK). */
- if (!notif_queue)
+ if (QUEUE_is_empty (notif_event_p, notif_stop.queue))
{
fprintf (stderr, "GDBserver exiting\n");
remote_close ();
@@ -3498,8 +3436,14 @@ handle_target_event (int err, gdb_client_data client_data)
}
else
{
- /* Something interesting. Tell GDB about it. */
- push_event (last_ptid, &last_status);
+ struct vstop_notif *vstop_notif
+ = xmalloc (sizeof (struct vstop_notif));
+
+ vstop_notif->status = last_status;
+ vstop_notif->ptid = last_ptid;
+ /* Push Stop notification. */
+ notif_push (¬if_stop,
+ (struct notif_event *) vstop_notif);
}
}
diff --git a/gdb/gdbserver/server.h b/gdb/gdbserver/server.h
index 929819e..7104ef7 100644
--- a/gdb/gdbserver/server.h
+++ b/gdb/gdbserver/server.h
@@ -265,8 +265,6 @@ extern void start_event_loop (void);
extern int handle_serial_event (int err, gdb_client_data client_data);
extern int handle_target_event (int err, gdb_client_data client_data);
-extern void push_event (ptid_t ptid, struct target_waitstatus *status);
-
/* Functions from hostio.c. */
extern int handle_vFile (char *, int, int *);
--
1.7.7.6