[GSOC 2014] Add JSON support for strace

[yangmin zhu]

Hi all,
I had cleaned my patch and here I send them here for a discussion.

Patch list:
0001-JSON-Import-the-basic-JSON-output-framework.patch
0002-JSON-Add-j-option-to-support-JSON-output.patch
0003-JSON-Add-support-for-syscalls-in-io.c.patch
0004-JSON-Add-support-to-entering-exiting-of-syscall.patch
0005-JSON-Add-basic-test-support-for-JSON-framework.patch
0006-JSON-Add-test-case-for-syscalls-in-io.c.patch
0007-JSON-Add-support-for-signals.patch


Patch 0001 show the internal implementation of the JSON framework, you
can ignore it if you don't care
the internal detail of the framework.
Patch 0002 modify strace to add a new option '-j' to enable the JSON
output format.

Patch 0003/0004/0007 shows how to use the JSON framework, you can take
them as a example to
understand how to modify the current existing strace code to support
JSON output format.
These 3 patches shows in 3 different ways of modifying strace:
1) The most common sys_* functions for printing the arguments of a syscall;
2) The entering/exiting of a syscall which will print the
name/retcode/description of a syscall;
3) The special signals in strace such as the '+++' signals;


Patch 0005/0006 give a test suit for the JSON framework. It's also a
good example for you to understand how
to parse the JSON output of strace. I wrote a simple parser in python,
It's easy and quick. If you want to use the
test suit, just cd to test directory and run json_test.sh, I suggest
you first install wdiff and corlordiff to make the output
look better.

Before the deadline of GSOC 2014(August 18), I will probably not
modify the base framework any more(or just some small
refactor), And I will put my energy to modify the existing strace code
to add JSON support for those sys_* functions in strace.

you can also get my code from my github and have a test:
1) git clone https://github.com/zym0017d/strace_GSOC/
2) cd strace_GSOC && make
3) cd test && make && ./json_test.sh

If you have any suggestions please let me know.
Thank you!
---
YangMin