| Message ID | 20210405093357.870395-1-tz.stoyanov@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | trace-cmd: Implement warning() in the library | expand |
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
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
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;
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(+)