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Emulate the behaviour of Linux mmap() on Solaris. Based on ideas and 

sample code due to Erik Boasson <eboasson@signaal.nl> and John Wehle
<john@feith.com>.
This commit is contained in:
Ulrich Weigand 2001-09-07 18:46:14 +00:00 committed by Alexandre Julliard
parent db9b54925d
commit c52a11efa5
1 changed files with 86 additions and 0 deletions
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86
library/port.c
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@ -396,6 +396,87 @@ int getrlimit (int resource, struct rlimit *rlim)
}
#endif /* HAVE_GETRLIMIT */
#ifdef __svr4__
/***********************************************************************
* solaris_try_mmap
*
* The purpose of this routine is to emulate the behaviour of
* the Linux mmap() routine if a non-NULL address is passed,
* but the MAP_FIXED flag is not set. Linux in this case tries
* to place the mapping at the specified address, *unless* the
* range is already in use. Solaris, however, completely ignores
* the address argument in this case.
*
* As Wine code occasionally relies on the Linux behaviour, e.g. to
* be able to map non-relocateable PE executables to their proper
* start addresses, or to map the DOS memory to 0, this routine
* emulates the Linux behaviour by checking whether the desired
* address range is still available, and placing the mapping there
* using MAP_FIXED if so.
*/
static int solaris_try_mmap (void *addr, size_t len, int prot, int flags,
int fildes, off_t off)
{
char * volatile result = NULL;
int pagesize = getpagesize();
pid_t pid;
/* We only try to map to a fixed address if
addr is non-NULL and properly aligned,
and MAP_FIXED isn't already specified. */
if ( !addr )
return FALSE;
if ( (uintptr_t)addr & (pagesize-1) )
return FALSE;
if ( flags & MAP_FIXED )
return FALSE;
/* We use vfork() to freeze all threads of the
current process. This allows us to check without
race condition whether the desired memory range is
already in use. Note that because vfork() shares
the address spaces between parent and child, we
can actually perform the mapping in the child. */
if ( (pid = vfork()) == -1 )
{
perror("solaris_try_mmap: vfork");
exit(1);
}
if ( pid == 0 )
{
int i;
char vec;
/* We call mincore() for every page in the desired range.
If any of these calls succeeds, the page is already
mapped and we must fail. */
for ( i = 0; i < len; i += pagesize )
if ( mincore( (caddr_t)addr + i, pagesize, &vec ) != -1 )
_exit(1);
/* Perform the mapping with MAP_FIXED set. This is safe
now, as none of the pages is currently in use. */
result = mmap( addr, len, prot, flags | MAP_FIXED, fildes, off );
if ( result == addr )
_exit(0);
if ( result != (void *) -1 ) /* This should never happen ... */
munmap( result, len );
_exit(1);
}
/* vfork() lets the parent continue only after the child
has exited. Furthermore, Wine sets SIGCHLD to SIG_IGN,
so we don't need to wait for the child. */
return result == addr;
}
#endif
/***********************************************************************
* wine_anon_mmap
*
@ -427,6 +508,11 @@ void *wine_anon_mmap( void *start, size_t size, int prot, int flags )
flags |= MAP_PRIVATE;
#endif
#ifdef __svr4__
if ( solaris_try_mmap( start, size, prot, flags, fdzero, 0 ) )
return start;
#endif
return mmap( start, size, prot, flags, fdzero, 0 );
}