diff options
| -rw-r--r-- | SystemTools.cxx | 96 |
1 files changed, 86 insertions, 10 deletions
diff --git a/SystemTools.cxx b/SystemTools.cxx index ac45b14..6a8520fe 100644 --- a/SystemTools.cxx +++ b/SystemTools.cxx @@ -34,6 +34,10 @@ #include <utility> #include <vector> +#ifdef _WIN32 +# include <cwchar> +#endif + // Work-around CMake dependency scanning limitation. This must // duplicate the above list of headers. #if 0 @@ -103,6 +107,9 @@ # if defined(_MSC_VER) && _MSC_VER >= 1800 # define KWSYS_WINDOWS_DEPRECATED_GetVersionEx # endif +# ifndef IO_REPARSE_TAG_APPEXECLINK +# define IO_REPARSE_TAG_APPEXECLINK (0x8000001BL) +# endif // from ntifs.h, which can only be used by drivers typedef struct _REPARSE_DATA_BUFFER { @@ -132,8 +139,46 @@ typedef struct _REPARSE_DATA_BUFFER { UCHAR DataBuffer[1]; } GenericReparseBuffer; + struct + { + ULONG Version; + WCHAR StringList[1]; + // In version 3, there are 4 NUL-terminated strings: + // * Package ID + // * Entry Point + // * Executable Path + // * Application Type + } AppExecLinkReparseBuffer; } DUMMYUNIONNAME; } REPARSE_DATA_BUFFER, *PREPARSE_DATA_BUFFER; + +namespace { +WCHAR* GetAppExecLink(PREPARSE_DATA_BUFFER data, size_t& len) +{ + // We only know the layout of version 3. + if (data->AppExecLinkReparseBuffer.Version != 3) { + return nullptr; + } + + WCHAR* pstr = data->AppExecLinkReparseBuffer.StringList; + + // Skip the package id and entry point strings. + for (int i = 0; i < 2; ++i) { + len = std::wcslen(pstr); + if (len == 0) { + return nullptr; + } + pstr += len + 1; + } + + // The third string is the executable path. + len = std::wcslen(pstr); + if (len == 0) { + return nullptr; + } + return pstr; +} +} #endif #if !KWSYS_CXX_HAS_ENVIRON_IN_STDLIB_H @@ -1343,8 +1388,8 @@ bool SystemTools::FileExists(const std::string& filename) return false; } #if defined(_WIN32) - DWORD attr = - GetFileAttributesW(Encoding::ToWindowsExtendedPath(filename).c_str()); + const std::wstring path = Encoding::ToWindowsExtendedPath(filename); + DWORD attr = GetFileAttributesW(path.c_str()); if (attr == INVALID_FILE_ATTRIBUTES) { return false; } @@ -1352,12 +1397,38 @@ bool SystemTools::FileExists(const std::string& filename) if (attr & FILE_ATTRIBUTE_REPARSE_POINT) { // Using 0 instead of GENERIC_READ as it allows reading of file attributes // even if we do not have permission to read the file itself - HANDLE handle = - CreateFileW(Encoding::ToWindowsExtendedPath(filename).c_str(), 0, 0, - nullptr, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, nullptr); + HANDLE handle = CreateFileW(path.c_str(), 0, 0, nullptr, OPEN_EXISTING, + FILE_FLAG_BACKUP_SEMANTICS, nullptr); if (handle == INVALID_HANDLE_VALUE) { - return false; + // A reparse point may be an execution alias (Windows Store app), which + // is similar to a symlink but it cannot be opened as a regular file. + // We must look at the reparse point data explicitly. + handle = CreateFileW( + path.c_str(), 0, 0, nullptr, OPEN_EXISTING, + FILE_FLAG_OPEN_REPARSE_POINT | FILE_FLAG_BACKUP_SEMANTICS, nullptr); + + if (handle == INVALID_HANDLE_VALUE) { + return false; + } + + byte buffer[MAXIMUM_REPARSE_DATA_BUFFER_SIZE]; + DWORD bytesReturned = 0; + + if (!DeviceIoControl(handle, FSCTL_GET_REPARSE_POINT, nullptr, 0, buffer, + MAXIMUM_REPARSE_DATA_BUFFER_SIZE, &bytesReturned, + nullptr)) { + CloseHandle(handle); + return false; + } + + CloseHandle(handle); + + PREPARSE_DATA_BUFFER data = + reinterpret_cast<PREPARSE_DATA_BUFFER>(&buffer[0]); + + // Assume that file exists if it is an execution alias. + return data->ReparseTag == IO_REPARSE_TAG_APPEXECLINK; } CloseHandle(handle); @@ -3011,11 +3082,7 @@ bool SystemTools::FileIsDirectory(const std::string& inName) bool SystemTools::FileIsExecutable(const std::string& name) { -#if defined(_WIN32) - return SystemTools::FileExists(name, true); -#else return !FileIsDirectory(name) && TestFileAccess(name, TEST_FILE_EXECUTE); -#endif } bool SystemTools::FileIsSymlink(const std::string& name) @@ -3164,6 +3231,15 @@ Status SystemTools::ReadSymlink(std::string const& newName, data->MountPointReparseBuffer.SubstituteNameLength / sizeof(WCHAR); substituteNameData = data->MountPointReparseBuffer.PathBuffer + data->MountPointReparseBuffer.SubstituteNameOffset / sizeof(WCHAR); + } else if (data->ReparseTag == IO_REPARSE_TAG_APPEXECLINK) { + // The reparse buffer is a list of 0-terminated non-empty strings, + // terminated by an empty string (0-0). We need the third string. + size_t destLen; + substituteNameData = GetAppExecLink(data, destLen); + if (substituteNameData == nullptr || destLen == 0) { + return Status::Windows(ERROR_SYMLINK_NOT_SUPPORTED); + } + substituteNameLength = static_cast<USHORT>(destLen); } else { return Status::Windows(ERROR_REPARSE_TAG_MISMATCH); } |