diff options
Diffstat (limited to 'winsup/cygwin/cygheap.h')
| -rw-r--r-- | winsup/cygwin/cygheap.h | 92 |
1 files changed, 91 insertions, 1 deletions
diff --git a/winsup/cygwin/cygheap.h b/winsup/cygwin/cygheap.h index 054297bd7..154ad6a84 100644 --- a/winsup/cygwin/cygheap.h +++ b/winsup/cygwin/cygheap.h @@ -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: |