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* cygheap.h (enum fcwd_version_t): Move here from path.cc.

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(class fcwd_access_t): Ditto.  Only declare methods.
	(class cwdstuff): Move fast_cwd_ptr and fast_cwd_version from shared
	DLL section here.
	* path.cc: Keep fcwd_access_t method definitions.
	(fcwd_access_t::fast_cwd_version): New method.
	(find_fast_cwd_pointer): Change comment.  Mention test on W8CP.
	(cwdstuff::init): Initialize fast_cwd_ptr and fast_cwd_version.
This commit is contained in:
Corinna Vinschen
2012-03-05 11:50:25 +00:00
parent 75effa37fc
commit a3904c655e
3 changed files with 228 additions and 194 deletions
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92
winsup/cygwin/cygheap.h
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@@ -204,7 +204,87 @@ public:
/* cwd cache stuff. */
class muto;
enum fcwd_version_t {
FCWD_OLD,
FCWD_W7,
FCWD_W8
};
/* This class is used to store the CWD starting with Windows Vista.
The CWD storage in the RTL_USER_PROCESS_PARAMETERS block is only
an afterthought now. The actual CWD storage is a FAST_CWD structure
which is allocated on the process heap. The new method only requires
minimal locking and it's much more multi-thread friendly. Presumably
it minimizes contention when accessing the CWD.
The class fcwd_access_t is supposed to encapsulate the gory implementation
details depending on OS version from the calling functions. */
class fcwd_access_t {
/* This is the layout used in Windows 8 developer preview. */
struct FAST_CWD_8 {
LONG ReferenceCount; /* Only release when this is 0. */
HANDLE DirectoryHandle;
ULONG OldDismountCount; /* Reflects the system DismountCount
at the time the CWD has been set. */
UNICODE_STRING Path; /* Path's Buffer member always refers
to the following Buffer array. */
LONG FSCharacteristics; /* Taken from FileFsDeviceInformation */
WCHAR Buffer[MAX_PATH];
};
/* This is the layout used in Windows 7 and Vista. */
struct FAST_CWD_7 {
UNICODE_STRING Path; /* Path's Buffer member always refers
to the following Buffer array. */
HANDLE DirectoryHandle;
LONG FSCharacteristics; /* Taken from FileFsDeviceInformation */
LONG ReferenceCount; /* Only release when this is 0. */
ULONG OldDismountCount; /* Reflects the system DismountCount
at the time the CWD has been set. */
WCHAR Buffer[MAX_PATH];
};
/* This is the old FAST_CWD structure up to the patch from KB 2393802,
release in February 2011. */
struct FAST_CWD_OLD {
LONG ReferenceCount; /* Only release when this is 0. */
HANDLE DirectoryHandle;
ULONG OldDismountCount; /* Reflects the system DismountCount
at the time the CWD has been set. */
UNICODE_STRING Path; /* Path's Buffer member always refers
to the following Buffer array. */
WCHAR Buffer[MAX_PATH];
};
union {
FAST_CWD_OLD fold;
FAST_CWD_7 f7;
FAST_CWD_8 f8;
};
#define IMPLEMENT(type, name) \
type name () { \
switch (fast_cwd_version ()) { \
case FCWD_OLD: \
default: \
return fold.name; \
case FCWD_W7: \
return f7.name; \
case FCWD_W8: \
return f8.name; \
} \
}
IMPLEMENT (LONG &, ReferenceCount)
IMPLEMENT (HANDLE &, DirectoryHandle)
IMPLEMENT (ULONG &, OldDismountCount)
IMPLEMENT (UNICODE_STRING &, Path)
IMPLEMENT (WCHAR *, Buffer)
void SetFSCharacteristics (LONG val);
static fcwd_version_t &fast_cwd_version (void);
public:
void CopyPath (UNICODE_STRING &target);
void Free (PVOID heap);
void FillIn (HANDLE dir, PUNICODE_STRING name, ULONG old_dismount_count);
static void SetDirHandleFromBufferPointer (PWCHAR buf_p, HANDLE dir);
static void SetVersionFromPointer (PBYTE buf_p, bool is_buffer);
};
class cwdstuff
{
@@ -217,6 +297,16 @@ private:
a native Win32 application. See cwdstuff::set for
how it gets set. See child_info_spawn::worker for how
it's evaluated. */
friend class fcwd_access_t;
/* fast_cwd_ptr is a pointer to the global RtlpCurDirRef pointer in
ntdll.dll pointing to the FAST_CWD structure which constitutes the CWD.
Unfortunately RtlpCurDirRef is not exported from ntdll.dll. */
fcwd_access_t **fast_cwd_ptr;
/* Type of FAST_CWD used on this system. Keeping this information
available in shared memory avoids to test for the version every time
around. Default to new version. */
fcwd_version_t fast_cwd_version;
void override_win32_cwd (bool, ULONG);
public: