Re: [PATCH] winedbg: gdb proxy mode: support qAttached packet

[Eric Pouech]

Paul Bolle a écrit :
> Add support for the qAttached packet. Main benefit is that if gdb was
> attached to a debuggee and it quits it will now ask if it should detach
> from the debuggee instead of asking whether the debuggee should be
> killed. (It still will ask whether the debuggee should be killed if it
> launched the debuggee itself).
> Signed-off-by: Paul Bolle
>
> Would it be better to add a new member to gdbctx instead of using a
> separate variable (qAttached_reply)?

yes, inclusion in gdbctx is preferred (and storage should rather be an 
integer rather than a string pointer)
A+

[PATCH v2] winedbg: gdb proxy mode: support qAttached packet

[Paul Bolle]

Add support for the qAttached packet. Main benefit is that gdb now will
ask if it should detach from the debuggee if it was attached to a
debuggee instead of asking whether the debuggee should be killed. (It
still will ask whether the debuggee should be killed if it launched the
debuggee itself).

Signed-off-by: Paul Bolle 
---
On Wed, 2009-11-04 at 21:42 +0100, Eric Pouech wrote:
> [...] inclusion in gdbctx is preferred (and storage should rather be an 
> integer rather than a string pointer)

programs/winedbg/gdbproxy.c |   25 +++++++++++++++++++++----
 1 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/programs/winedbg/gdbproxy.c b/programs/winedbg/gdbproxy.c
index 4f12481..0f5088c 100644
--- a/programs/winedbg/gdbproxy.c
+++ b/programs/winedbg/gdbproxy.c
@@ -109,6 +109,8 @@ struct gdb_context
     struct gdb_ctx_Xpoint       Xpoints[NUM_XPOINT];
     /* Unix environment */
     unsigned long               wine_segs[3];   /* load addresses of the ELF wine exec segments (text, bss and data) */
+    /* attached or launched? */
+    int                         attached;
 };

static BOOL tgt_process_gdbproxy_read(HANDLE hProcess, const void* addr,
@@ -1794,6 +1796,15 @@ static enum packet_return packet_query(struct gdb_context* gdbctx)
             return packet_done;
         }
         break;
+    case 'A':
+        /* Since gdb's multiprocess protocol extensions aren't supported, this
+         * shouldn't be "qAttached:PID", just "qAttached", but check anyway. */
+        if (gdbctx->in_packet_len == 8 && strncmp(gdbctx->in_packet, "Attached", 8) == 0)
+        {
+            packet_reply(gdbctx, gdbctx->attached ? "1": "0", 1);
+            return packet_done;
+        }
+        break;
     case 'C':
         if (gdbctx->in_packet_len == 1)
         {
@@ -2179,6 +2190,7 @@ static int fetch_data(struct gdb_context* gdbctx)

#define FLAG_NO_START   1
 #define FLAG_WITH_XTERM 2
+#define FLAG_ATTACHED   4

static BOOL gdb_exec(const char* wine_path, unsigned port, unsigned flags)
 {
@@ -2318,6 +2330,7 @@ static BOOL gdb_init_context(struct gdb_context* gdbctx, unsigned flags)
     gdbctx->in_trap = FALSE;
     gdbctx->trace = /*GDBPXY_TRC_PACKET | GDBPXY_TRC_COMMAND |*/ GDBPXY_TRC_COMMAND_ERROR | GDBPXY_TRC_COMMAND_FIXME | GDBPXY_TRC_WIN32_EVENT;
     gdbctx->process = NULL;
+    gdbctx->attached = (flags & FLAG_ATTACHED) ? 1 : 0;
     for (i = 0; i < NUM_XPOINT; i++)
         gdbctx->Xpoints[i].type = -1;
     for (i = 0; i < sizeof(gdbctx->wine_segs) / sizeof(gdbctx->wine_segs[0]); i++)
@@ -2350,6 +2363,7 @@ static int gdb_remote(unsigned flags)
     struct pollfd       pollfd;
     struct gdb_context  gdbctx;
     BOOL                doLoop;
+    BOOL                kill;

for (doLoop = gdb_init_context(&gdbctx, flags); doLoop;)
     {
@@ -2365,8 +2379,8 @@ static int gdb_remote(unsigned flags)
             {
                 if (gdbctx.trace & GDBPXY_TRC_LOWLEVEL)
                     fprintf(stderr, "Gdb hung up\n");
-                /* kill also debuggee process - questionnable - */
-                detach_debuggee(&gdbctx, TRUE);
+                kill = (flags & FLAG_ATTACHED) ? FALSE : TRUE;
+                detach_debuggee(&gdbctx, kill);
                 doLoop = FALSE;
                 break;
             }
@@ -2412,8 +2426,11 @@ int gdb_main(int argc, char* argv[])
         }
         return -1;
     }
-    if (dbg_active_attach(argc, argv) == start_ok ||
-        dbg_active_launch(argc, argv) == start_ok)
+    if (dbg_active_attach(argc, argv) == start_ok) {
+        gdb_flags |= FLAG_ATTACHED;
+        return gdb_remote(gdb_flags);
+    }
+    else if (dbg_active_launch(argc, argv) == start_ok)
         return gdb_remote(gdb_flags);
 #else
     fprintf(stderr, "GdbProxy mode not supported on this platform\n");