On Mon, Jul 28, 2014 at 8:44 AM, yangmin zhu <zym00...@gmail.com> wrote: > Hi Dmitry, > > I'm working to modify strace to support JSON, but I just encounter a > big problem recently and I could not find > out a suitable way to get through. > > the problem is: > 1), as you know, I designed a framework to support the JSON output and > the core of the framework is to hook the metadata printed by > tprintf(). > I then modify strace code to use this framework. But I found that the > code is becoming more and more complicated(or ugly) > when I modify some complicated functions such as sys_clone() and sys_ioctl(). > > 2), I also found a flaw in my hook framework: I passed the va_list > variable to vfprintf() and reuse this variable after the call, But I > just found that > the man-page of va_arg says: "If ap is passed to a function that uses > va_arg(ap,type) then the value of ap is undefined after the return of > that function." > this indicate that although my current code worked, but the behavior > is in fact undefined which may not work in another system.
man va_copy > so I rethink my design to support JSON output: > The basic framework is designed too complicated and it seems we can in > fact modify only small part of strace to make it support JSON. (maybe > we can reuse most > of the current tprintf/tprints functions). > I'm also trying to find workaround for arg_list() problem, I thought > about the arg_copy(), But It couldn't fix the problem in a clean > way(especially when the format string contain multiple specifier). and > because of this I'm trying to redesign the framework to bypass these > problems. > > IMHO, I'm afraid that I could not finish modifying all the sys_* > functions in strace (there are 300+ such functions in about 35 files) > before the deadline of GSOC. > But I think once I got a better basic framework design it would help > to modify the current to suport JSON output witout heavy effort. > > I will post my new design to mailing list ASAP, and I will continue my > work after the GSOC deadline. So I hope > If you have any suggestions, please let me know. > > Thank you. > --- > YangMin > > ------------------------------------------------------------------------------ > Infragistics Professional > Build stunning WinForms apps today! > Reboot your WinForms applications with our WinForms controls. > Build a bridge from your legacy apps to the future. > http://pubads.g.doubleclick.net/gampad/clk?id=153845071&iu=/4140/ostg.clktrk > _______________________________________________ > Strace-devel mailing list > Strace-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/strace-devel ------------------------------------------------------------------------------ Infragistics Professional Build stunning WinForms apps today! Reboot your WinForms applications with our WinForms controls. Build a bridge from your legacy apps to the future. http://pubads.g.doubleclick.net/gampad/clk?id=153845071&iu=/4140/ostg.clktrk _______________________________________________ Strace-devel mailing list Strace-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/strace-devel
