* exceptions.cc (_cygtls::handle_exceptions): In case of a

	STATUS_ACCESS_VIOLATION, check if the page is a mmaped page beyond
	a file's EOF.  Generate SIGBUS instead of SIGSEGV then.
	* mmap.cc (__PROT_ATTACH): New define.
	(__PROT_FILLER): Ditto.
	(fh_anonymous): Rename from fh_paging_file;
	(fh_disk_file): New global static variable.
	(attached): New inline function.
	(filler): Ditto.
	(gen_create_protect): Split off from gen_protect to use the file's
	access mode to create mapping always with maximum allowed protections.
	(gen_protect): Accomodate pages attached beyond EOF.  Use symbolic
	values instead of numerics when possible.  Drop create parameter.
	(gen_access): Use file's access mode instead of protection.
	(CreateMapping9x): Create named mapping names so that different
	creation access modes result in different mappings.
	(CreateMappingNT): Only reserve attached pages, don't commit them.
	(MapViewNT): Ditto.  Set AT_ROUND_TO_PAGE for all non-NULL base
	addresses.
	(mmap_func_t): Define CreateMapping and MapView function pointers
	with additional openflags parameter.
	(class mmap_record): Add openflags member.
	(mmap_record::mmap_record): Add openflags parameter.
	(mmap_record::get_openflags): New accessor.
	(mmap_record::attached): Call global attached function.
	(mmap_record::filler): Call global filler function.
	(mmap_record::gen_create_protect): Call global gen_create_protect
	function.
	(mmap_record::gen_protect): Drop create parameter.
	(mmap_record::alloc_fh): Set fhandler's access flags.
	(list::search_record): Accomodate filler pages.
	(list::set): Use inode number as hash value.
	(map::get_list_by_fd): Check hash value against file's inode number.
	(mmap_is_attached_page): New function to evaluate if a given address
	is on a attached page.  Called from _cygtls::handle_exceptions.
	(mmap_worker): New function to do mapping and bookkeeping in a
	single call.
	(mmap64): Use roundup2 to round length to pagesize alignment.
	Initialize global fhandlers.  Simplify anonymous initialization.
	Add SUSv3 compatible check of file open mode vs. requested protection.
	Try creating new file handles to allow maximum page protection.
	Allow creating attached pages in case of mapping beyond EOF.
	Close new file handle if one has been created.
	(munmap): Align len to pagesize.
	(msync): Rework argument checks. Align len to pagesize.
	(mprotect): Ditto.  Accomodate attached pages.
	(mlock): Use roundup/rounddown macros instead of homemade expressions.
	(munlock): Add page alignment as in mlock.
	(fhandler_dev_zero::munmap): Fix unmapping of non-private mappings.
	(fhandler_dev_zero::fixup_mmap_after_fork): Accomodate filler pages.
	(fixup_mmaps_after_fork): Don't fail if attached pages couldn't be
	created in child.  Avoid superfluous call to VirtualFree.  Check for
	original allocation protection to fix PAGE_WRITECOPY protection.
	* ntdll.h: Revert deletion of AT_ROUND_TO_PAGE define.
	* winsup.h (mmap_is_attached_page): Declare.

1 files changed, 2 insertions, 1 deletions

diff --git a/winsup/cygwin/winsup.h b/winsup/cygwin/winsup.h
index b16313426..d441877eb 100644
--- a/winsup/cygwin/winsup.h
+++ b/winsup/cygwin/winsup.h
@@ -299,8 +299,9 @@ extern "C" int low_priority_sleep (DWORD) __attribute__ ((regparm (1)));
 /* Returns the real page size, not the allocation size. */
 size_t getsystempagesize ();
 
-/* Init mmap function pointers. */
+/* mmap functions. */
 void mmap_init ();
+bool mmap_is_attached_page (ULONG_PTR);
 
 int winprio_to_nice (DWORD) __attribute__ ((regparm (1)));
 DWORD nice_to_winprio (int &) __attribute__ ((regparm (1)));