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. 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
