svn commit: branches/uClibc-nptl/libc/misc/dirent

[Mike Frysinger]

On Thursday 15 May 2008, Carmelo AMOROSO wrote:
> Mike Frysinger wrote:
> > On Wednesday 05 December 2007, carmelo at uclibc.org wrote:
> >> Author: carmelo
> >> Date: 2007-12-05 09:25:08 -0800 (Wed, 05 Dec 2007)
> >> New Revision: 20626
> >>
> >> Log:
> >> Fix opendir problem when statically linked due to a missing
> >> initialization of the mutex field within DIR struct.
> >> When linked dynamically instead, __pthread_mutex_init will
> >> initialize the mutex itself. Without this fix, any call to
> >> readdir will stuck forever trying to acquire the mutex.
> >
> > sorry, but i dont follow.  we call __pthread_mutex_init() on the dd_lock
> > member of the dirent structure which should initialize the mutex just
> > fine. you cant assume that zeroing the structure is the same as
> > initializing the mutex.  that is why we have these initializer functions
> > in the first place. are you suggesting that the __pthread_mutex_init()
> > function is not doing its job ?
>
> yes exactly... but only if statically linked. I suspect that in this
> case the __pthread_mutex_init is a nop...
> likely due to weak aliasing... however, glibc does exactly the same call
> to memset
> and it uses
>
> #ifndef NOT_IN_libc
>  __libc_lock_init (dirp->lock);
> #endif
>
> instead of  __pthread_mutex_init(&(ptr->dd_lock), NULL);

can you provide a test case ?  i'd like to fix the real problem ... adding a 
memset() just ignores the larger issue with every function that does 
something similar.
-mike
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