Re: [PATCH 2/4] gdbserver: Add debug-file option

Alan Hayward
2019-04-17T09:39:53Z

>
> On 16 Apr 2019, at 15:43, Eli Zaretskii <eliz@gnu.org> wrote:
>
>> From: Alan Hayward <Alan.Hayward@arm.com>
>> CC: nd <nd@arm.com>, Alan Hayward <Alan.Hayward@arm.com>
>> Date: Tue, 16 Apr 2019 10:17:41 +0000
>>
>> gdb/doc/ChangeLog:
>>
>> 2019-04-16 Alan Hayward <alan.hayward@arm.com>
>>
>> * gdb.texinfo
>> (Other Command-Line Arguments for gdbserver): Add debug-file
>
> The node name in parentheses should be on the same line as
> gdb.texinfo.

Fixed.

>
>> (Monitor Commands for gdbserver): Likewise.
>> (gdbserver man): Likewise.
>
> It is better to have a list of node names in parentheses, with only
> one description, than having separate entries that say "Likewise”.

Wasn’t aware it could be done that way. Fixed.

>
>> +@cindex @option{--debug-file}, @code{gdbserver} option
>
> I think it would be good to have here an additional index entry:
>
> @cindex @code{gdbserver}, send all debug output to a single file

Makes sense. Added.

>
>> +The @option{--debug-file=filename} option tells @code{gdbserver} to
> ^^^^^^^^
> "filename" should be in @var here, as it is a parameter.

Done.

>
>> +write any debug output to the given file. These options are intended
> ^^^^^^^^^^^^^^^^^
> "to the given @var{filename}", so as to reference the parameter.

Done.

>
>> +@item --debug-file=filename
>> +Instruct @code{gdbserver} to send any debug output to the given file.
>
> Same here.

Done.

>
> The documentation changes are okay with these nits fixed.
>
> Thanks.

>
> On 16 Apr 2019, at 20:39, Tom Tromey <tom@tromey.com> wrote:
>
>>>>>> "Alan" == Alan Hayward <Alan.Hayward@arm.com> writes:
>
> Alan> Add command line option to send all debug output to a given file.
> Alan> Always default back to stderr.
>
> Alan> Add matching monitor command. Add documentation.
>
> Thanks. The code parts of this are ok.
>
> One little nit:
>
> Alan> + debug_file = fptr;
> Alan> + return;
> Alan> +}
>
> ...this "return;" can be removed.
>

Done.

Thanks!

Pushed the following:

diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog
index 27e65ea56c..64073278fa 100644
--- a/gdb/doc/ChangeLog
+++ b/gdb/doc/ChangeLog
@@ -1,3 +1,9 @@
+2019-04-17 Alan Hayward <alan.hayward@arm.com>
+
+ * gdb.texinfo (Other Command-Line Arguments for gdbserver)
+ (Monitor Commands for gdbserver)
+ (gdbserver man): Add debug-file option.
+
2019-04-08 Kevin Buettner <kevinb@redhat.com>

* python.texi (Inferiors In Python): Rename
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index f410d026b8..a3a5f3e28c 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -21332,8 +21332,12 @@ The @option{--debug} option tells @code{gdbserver} to display extra
status information about the debugging process.
@cindex @option{--remote-debug}, @code{gdbserver} option
The @option{--remote-debug} option tells @code{gdbserver} to display
-remote protocol debug output. These options are intended for
-@code{gdbserver} development and for bug reports to the developers.
+remote protocol debug output.
+@cindex @option{--debug-file}, @code{gdbserver} option
+@cindex @code{gdbserver}, send all debug output to a single file
+The @option{--debug-file=@var{filename}} option tells @code{gdbserver} to
+write any debug output to the given @var{filename}. These options are intended
+for @code{gdbserver} development and for bug reports to the developers.

@cindex @option{--debug-format}, @code{gdbserver} option
The @option{--debug-format=option1[,option2,...]} option tells
@@ -21433,6 +21437,10 @@ Disable or enable general debugging messages.
Disable or enable specific debugging messages associated with the remote
protocol (@pxref{Remote Protocol}).

+@item monitor set debug-file filename
+@itemx monitor set debug-file
+Send any debug output to the given file, or to stderr.
+
@item monitor set debug-format option1@r{[},option2,...@r{]}
Specify additional text to add to debugging messages.
Possible options are:
@@ -44563,6 +44571,11 @@ Instruct @code{gdbserver} to display remote protocol debug output.
This option is intended for @code{gdbserver} development and for bug reports to
the developers.

+@item --debug-file=@var{filename}
+Instruct @code{gdbserver} to send any debug output to the given @var{filename}.
+This option is intended for @code{gdbserver} development and for bug reports to
+the developers.
+
@item --debug-format=option1@r{[},option2,...@r{]}
Instruct @code{gdbserver} to include extra information in each line
of debugging output.
diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
index 0581f59b5d..d3380d6145 100644
--- a/gdb/gdbserver/ChangeLog
+++ b/gdb/gdbserver/ChangeLog
@@ -1,3 +1,12 @@
+2019-04-17 Alan Hayward <alan.hayward@arm.com>
+
+ * debug.c (debug_set_output): New function.
+ (debug_vprintf): Send output to debug_file.
+ (debug_flush): Likewise.
+ * debug.h (debug_set_output): New declaration.
+ * server.c (handle_monitor_command): Add debug-file option.
+ (captured_main): Likewise.
+
2019-04-17 Alan Hayward <alan.hayward@arm.com>

* debug.c (remote_debug): Add definition.
diff --git a/gdb/gdbserver/debug.c b/gdb/gdbserver/debug.c
index 7c4c77afe2..d80cd52540 100644
--- a/gdb/gdbserver/debug.c
+++ b/gdb/gdbserver/debug.c
@@ -23,6 +23,9 @@
int remote_debug = 0;
#endif

+/* Output file for debugging. Default to standard error. */
+FILE *debug_file = stderr;
+
/* Enable miscellaneous debugging output. The name is historical - it
was originally used to debug LinuxThreads support. */
int debug_threads;
@@ -30,6 +33,38 @@ int debug_threads;
/* Include timestamps in debugging output. */
int debug_timestamp;

+#if !defined (IN_PROCESS_AGENT)
+
+/* See debug.h. */
+
+void
+debug_set_output (const char *new_debug_file)
+{
+ /* Close any existing file and reset to standard error. */
+ if (debug_file != stderr)
+ {
+ fclose (debug_file);
+ }
+ debug_file = stderr;
+
+ /* Catch empty filenames. */
+ if (new_debug_file == nullptr || strlen (new_debug_file) == 0)
+ return;
+
+ FILE *fptr = fopen (new_debug_file, "w");
+
+ if (fptr == nullptr)
+ {
+ debug_printf ("Cannot open %s for writing. %s. Switching to stderr.\n",
+ new_debug_file, strerror (errno));
+ return;
+ }
+
+ debug_file = fptr;
+}
+
+#endif
+
/* Print a debugging message.
If the text begins a new line it is preceded by a timestamp.
We don't get fancy with newline checking, we just check whether the
@@ -50,11 +85,11 @@ debug_vprintf (const char *format, va_list ap)
seconds s = duration_cast<seconds> (now.time_since_epoch ());
microseconds us = duration_cast<microseconds> (now.time_since_epoch ()) - s;

- fprintf (stderr, "%ld.%06ld ", (long) s.count (), (long) us.count ());
+ fprintf (debug_file, "%ld.%06ld ", (long) s.count (), (long) us.count ());
}
#endif

- vfprintf (stderr, format, ap);
+ vfprintf (debug_file, format, ap);

#if !defined (IN_PROCESS_AGENT)
if (*format)
@@ -69,7 +104,7 @@ debug_vprintf (const char *format, va_list ap)
void
debug_flush (void)
{
- fflush (stderr);
+ fflush (debug_file);
}

/* Notify the user that the code is entering FUNCTION_NAME.
diff --git a/gdb/gdbserver/debug.h b/gdb/gdbserver/debug.h
index c8d5e3365e..f65c91c9eb 100644
--- a/gdb/gdbserver/debug.h
+++ b/gdb/gdbserver/debug.h
@@ -21,6 +21,11 @@

#if !defined (IN_PROCESS_AGENT)
extern int remote_debug;
+
+/* Switch all debug output to DEBUG_FILE. If DEBUG_FILE is nullptr or an
+ empty string, or if the file cannot be opened, then debug output is sent to
+ stderr. */
+void debug_set_output (const char *debug_file);
#endif

extern int debug_threads;
diff --git a/gdb/gdbserver/server.c b/gdb/gdbserver/server.c
index 3f6c849dbc..36510ad1b2 100644
--- a/gdb/gdbserver/server.c
+++ b/gdb/gdbserver/server.c
@@ -1403,6 +1403,10 @@ handle_monitor_command (char *mon, char *own_buf)
write_enn (own_buf);
}
}
+ else if (strcmp (mon, "set debug-file") == 0)
+ debug_set_output (nullptr);
+ else if (startswith (mon, "set debug-file "))
+ debug_set_output (mon + sizeof ("set debug-file ") - 1);
else if (strcmp (mon, "help") == 0)
monitor_show_help ();
else if (strcmp (mon, "exit") == 0)
@@ -3649,6 +3653,8 @@ captured_main (int argc, char *argv[])
}
else if (strcmp (*next_arg, "--remote-debug") == 0)
remote_debug = 1;
+ else if (startswith (*next_arg, "--debug-file="))
+ debug_set_output ((*next_arg) + sizeof ("--debug-file=") -1);
else if (strcmp (*next_arg, "--disable-packet") == 0)
{
gdbserver_show_disableable (stdout);