writejump purpose

[Robert Lunnon]

In kthread.c there is this code that is only defined for I386 glibc, but the 
solaris port uses Solaris libc so the function does nothing. What is the 
purpose of this function and exactly what should the semantics be ?

BOb

static inline void writejump( const char *symbol, void *dest )
{
#if defined(__GLIBC__) && defined(__i386__)
    unsigned char *addr = wine_dlsym( RTLD_NEXT, symbol, NULL, 0 );

if (!addr) return;

/* write a relative jump at the function address */
    mprotect((void*)((unsigned int)addr & ~(getpagesize()-1)), 5, PROT_READ|
PROT_EXEC|PROT_WRITE);
    addr[0] = 0xe9;
    *(int *)(addr+1) = (unsigned char *)dest - (addr + 5);
    mprotect((void*)((unsigned int)addr & ~(getpagesize()-1)), 5, PROT_READ|
PROT_EXEC);

# ifdef HAVE_VALGRIND_MEMCHECK_H
    VALGRIND_DISCARD_TRANSLATIONS( addr, 5 );
# endif
#endif  /* __GLIBC__ && __i386__ */
}

[Marcus Meissner]

On Mon, Apr 25, 2005 at 07:59:30AM +1000, Robert Lunnon wrote:
> In kthread.c there is this code that is only defined for I386 glibc, but the 
> solaris port uses Solaris libc so the function does nothing. What is the 
> purpose of this function and exactly what should the semantics be ?

It is overwriting the __errno_location() handler in libc with a WINE threadsafe
one.

I am not sure whether Solaris needs it.

Ciao, Marcus