[PATCH] Fix problem with file locking used before initialised

Antony KING antony.king@st.com
Tue Feb 1 19:14:00 GMT 2005

Please find attached a revised version of the following patch (replacing 
the original submission) which adds some missing #includes of "local.h" 
in files which had CHECK_INIT() calls added.

(I have also attached the patch file as text this time instead of as a 
gzip'd attachment for easier perusal).



Antony King wrote:
> Please find attached a patch against libc in newlib to fix I a problem I 
> have encountered in the use of the _flockfile/_funlockfile API on the 
> standard I/O streams (stderr, stdout and stdin).
> The problems stems from the fact that the FILE objects for these I/O 
> streams are initially statically allocated in the global re-entrancy 
> structure (aka the "impure" pointer) and they are not 100% initialised 
> by static initialisation. This is overcome by the use of the CHECK_INIT 
> and _REENT_SMALL_CHECK_INIT macros which complete the initialisation of 
> the standard FILE I/O objects in a re-entrancy structure. As part of the 
> initialisation of the standard I/O FILE objects the file lock objects 
> are initialised.
> Unfortunately the _flockfile/_funlockfile functions are used before 
> CHECK_INIT is called and therefore the FILE lock object could end up in 
> an unknown state depending on the implementation of the FILE lock object 
> and the method of initialisation. To solve this problem it is necessary 
> to call CHECK_INIT before _flockfile/_funlockfile are called in any 
> function that takes a FILE * object as an argument (which normally is a 
> user level function). The attached patch attempts to fix this problem.
> Note that I have modified some machine specific files unfortunately I am 
> unable to test so you may not wish to commit these changes (powerpc and 
> arm files).
> Cheers,
> Antony.
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