Re: [Bug win32/14529] Make gdb capable of JIT-debugging on W32

LRN
2012-09-29T19:32:54Z

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On 29.09.2012 17:05, Eli Zaretskii wrote:
>> Date: Sat, 29 Sep 2012 16:42:03 +0400 From: LRN
>> <lrn1986@gmail.com>
>>
>> +@kindex signal-event +@item signal-event @var{id} +This command
>> signals an event with user-provided @var{id}. Used to resume
>> crashing +process when attached to it using W32 JIT debugging
>> (AeDebug).
>
> First, please use "MS-Windows" instead of "W32".
OK, although it might not be technically correct. I have no idea
whether ReactOS implements this debugging facility or not, but if it
does, then it is not right to name it "MS-Windows", since ReactOS is
neither MS, nor Windows.
I usually use "W32", because most of the time doing something with
WinAPI means interacting with Win32 subsystem, which, as i've
mentioned above, [is not/will not be] implemented exclusively by Windows.
Now, since GNU folks frown upon "win" in Win32, and naming it Woe32
sounds weird to me, i just use "W32".
Anyway, i've changed the patch.

> More importantly, I think we should document the Registry entry
> the user needs to tweak, and how to define it, in order to install
> GDB as a JIT debugger. In other words, the above does not explain
> enough about the expected use of this command, which (AFAIU) is
> from the GDB command line using the -ex switch, which I understand
> is the only way to get hold of the mysterious ID parameter this
> command needs.
>
Done.

Hopefully i didn't screw up texinfo file with wrong commands or
formatting.

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From 68db59b52726d0838b5974ec201becfebed8f27d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=D0=A0=D1=83=D1=81=D0=BB=D0=B0=D0=BD=20=D0=98=D0=B6=D0=B1=D1?=
=?UTF-8?q?=83=D0=BB=D0=B0=D1=82=D0=BE=D0=B2?= <lrn1986@gmail.com>
Date: Sat, 29 Sep 2012 18:16:16 +0400
Subject: [PATCH] Make gdb JIT-capable (MS-Windows)

Adds the signal-event command (MS-Windows-only) that signals
an event with user-provided ID. Used to resume crashing
process when attached to it via MS-Windows JIT debugging (AeDebug).

PR gdb/14529
---
gdb/doc/gdb.texinfo | 26 ++++++++++++++++++++++++++
gdb/windows-nat.c | 22 ++++++++++++++++++++++
2 files changed, 48 insertions(+)

diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 5fcbada..555563a 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -18859,6 +18859,32 @@ This is a Cygwin-specific alias of @code{info shared}.
This command loads symbols from a dll similarly to
add-sym command but without the need to specify a base address.

+@kindex signal-event
+@item signal-event @var{id}
+This command signals an event with user-provided @var{id}. Used to resume
+crashing process when attached to it using MS-Windows JIT debugging (AeDebug).
+
+To use it, create or edit the following keys in
+@code{HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AeDebug} and/or
+@code{HKLM\SOFTWARE\Wow6432Node\Microsoft\Windows NT\CurrentVersion\AeDebug}
+(for x86_64 versions):
+
+@itemize @minus
+@item
+Debugger (REG_SZ) - a command to launch the debugger. Suggested command is:
+<fully-qualified-path-to-gdb.exe> -ex "attach %ld" -ex "signal-event %ld"
+-ex "c"
+
+First %ld will be replaced by process ID, second %ld will be replaced by ID
+of the event that blocks the crashing process, waiting for debugger to attach.
+
+@item
+Auto (REG_SZ) - either @code{1} or @code{0}. @code{1} will make the system run
+debugger specified by Debugger key automatically, @code{0} will cause a dialog
+box with "OK" and "Cancel" buttons to appear, which allows the user to either
+terminate crashing process (OK) or debug it (Cancel).
+@end itemize
+
@kindex set cygwin-exceptions
@cindex debugging the Cygwin DLL
@cindex Cygwin DLL, debugging
diff --git a/gdb/windows-nat.c b/gdb/windows-nat.c
index 905d4bf..f003ece 100644
--- a/gdb/windows-nat.c
+++ b/gdb/windows-nat.c
@@ -933,6 +933,25 @@ dll_symbol_command (char *args, int from_tty)
safe_symbol_file_add (args, from_tty, NULL, 0, OBJF_SHARED | OBJF_USERLOADED);
}

+static void
+signal_event_command (char *args, int from_tty)
+{
+ uintptr_t event_id = 0;
+ char *endargs = NULL;
+
+ if (args == NULL)
+ error (_("signal-event requires an argument (integer event id)"));
+
+ event_id = strtoumax (args, &endargs, 10);
+
+ if ((errno == ERANGE) || (event_id == 0) || (event_id > UINTPTR_MAX) ||
+ ((HANDLE) event_id == INVALID_HANDLE_VALUE))
+ error (_("Failed to convert `%s' to event id"), args);
+
+ SetEvent ((HANDLE) event_id);
+ CloseHandle ((HANDLE) event_id);
+}
+
/* Handle DEBUG_STRING output from child process.
Cygwin prepends its messages with a "cygwin:". Interpret this as
a Cygwin signal. Otherwise just print the string as a warning. */
@@ -2547,6 +2566,9 @@ _initialize_windows_nat (void)
cygwin_internal (CW_SET_DOS_FILE_WARNING, 0);
#endif

+ c = add_com ("signal-event", class_run, signal_event_command,
+ _("Signal an object with ID."));
+
c = add_com ("dll-symbols", class_files, dll_symbol_command,
_("Load dll library symbols from FILE."));
set_cmd_completer (c, filename_completer);
--
1.7.11