* [PATCH] trace-cmd: Implement warning() in the library
@ 2021-04-05 9:33 Tzvetomir Stoyanov (VMware)
2021-04-05 13:59 ` Steven Rostedt
0 siblings, 1 reply; 3+ messages in thread
From: Tzvetomir Stoyanov (VMware) @ 2021-04-05 9:33 UTC (permalink / raw)
To: rostedt; +Cc: linux-trace-devel
The warning() function is used in a lot of places in the trace-cmd
library, but there is no implementation. The function is implemented in
the trace-cmd application. Added a weak implementation in the library, in
case the function in not implemented in the application, using that
library.
Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
Depends on "[v4] trace-cmd: Remove all die()s from trace-cmd library"
https://patchwork.kernel.org/project/linux-trace-devel/patch/20210405092100.869572-1-tz.stoyanov@gmail.com/
lib/trace-cmd/trace-util.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/lib/trace-cmd/trace-util.c b/lib/trace-cmd/trace-util.c
index db7bead6..0ee842e5 100644
--- a/lib/trace-cmd/trace-util.c
+++ b/lib/trace-cmd/trace-util.c
@@ -368,6 +368,16 @@ static int __vlib_warning(const char *fmt, va_list ap)
return ret;
}
+void __weak warning(const char *fmt, ...)
+{
+ va_list ap;
+
+ va_start(ap, fmt);
+ __vlib_warning(fmt, ap);
+ va_end(ap);
+}
+
+
void __weak tracecmd_lib_fatal(const char *fmt, ...)
{
int ret;
--
2.30.2
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] trace-cmd: Implement warning() in the library
2021-04-05 9:33 [PATCH] trace-cmd: Implement warning() in the library Tzvetomir Stoyanov (VMware)
@ 2021-04-05 13:59 ` Steven Rostedt
2021-04-05 14:23 ` Steven Rostedt
0 siblings, 1 reply; 3+ messages in thread
From: Steven Rostedt @ 2021-04-05 13:59 UTC (permalink / raw)
To: Tzvetomir Stoyanov (VMware); +Cc: linux-trace-devel
On Mon, 5 Apr 2021 12:33:57 +0300
"Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com> wrote:
> The warning() function is used in a lot of places in the trace-cmd
> library, but there is no implementation. The function is implemented in
> the trace-cmd application. Added a weak implementation in the library, in
> case the function in not implemented in the application, using that
> library.
>
Isn't the "warning()" function implemented in libtraceevent? That's where
it would be used as it is weak there.
But honestly, I think we should change the libtraceveent warning to
"tep_warning()" if we haven't already done so.
/me goes to look at the code.
-- Steve
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] trace-cmd: Implement warning() in the library
2021-04-05 13:59 ` Steven Rostedt
@ 2021-04-05 14:23 ` Steven Rostedt
0 siblings, 0 replies; 3+ messages in thread
From: Steven Rostedt @ 2021-04-05 14:23 UTC (permalink / raw)
To: Tzvetomir Stoyanov (VMware); +Cc: linux-trace-devel
On Mon, 5 Apr 2021 09:59:20 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:
> On Mon, 5 Apr 2021 12:33:57 +0300
> "Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com> wrote:
>
> > The warning() function is used in a lot of places in the trace-cmd
> > library, but there is no implementation. The function is implemented in
> > the trace-cmd application. Added a weak implementation in the library, in
> > case the function in not implemented in the application, using that
> > library.
> >
>
> Isn't the "warning()" function implemented in libtraceevent? That's where
> it would be used as it is weak there.
>
> But honestly, I think we should change the libtraceveent warning to
> "tep_warning()" if we haven't already done so.
>
> /me goes to look at the code.
OK, so what I think we need to do is have this:
void __weak tep_print_error(const char *fmt, const char *app, va_list ap)
{
if (errno)
perror(app);
fprintf(stderr, " ");
vfprintf(stderr, fmt, ap);
fprintf(stderr, "\n");
}
That gets the format and a va_list, and this is the weak function that
anything can overwrite (like KernelShark to have a pop up on error?).
Then we can have functions:
void __weak tep_vwarning(const char *fmt, va_list ap)
{
tep_print_error(fmt, "libtraceevent", ap);
}
void __weak tep_warning(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
tep_vwarning(fmt, ap);
va_end(ap);
}
And the same for libtracefs and libtracecmd.
where it will have a tracefs_warning() and a tracecmd_warning() functions
defined. Then an app can overwrite how tep_print_error() works, as well as
tep_vwarning works (or tracefs_vwarning() etc).
Hmm, thinking about this, there's no reason to have tep_warning() weak,
because by overwriting tep_vwarning(), you have full control of
tep_warning().
-- Steve
^ permalink raw reply [flat|nested] 3+ messages in thread
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2021-04-05 9:33 [PATCH] trace-cmd: Implement warning() in the library Tzvetomir Stoyanov (VMware)
2021-04-05 13:59 ` Steven Rostedt
2021-04-05 14:23 ` Steven Rostedt
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