https://git.reactos.org/?p=reactos.git;a=commitdiff;h=7481bda679eccdf1eba3666e500074dcb966e748
commit 7481bda679eccdf1eba3666e500074dcb966e748 Author: Bișoc George <[email protected]> AuthorDate: Sat Mar 28 19:17:10 2020 +0100 Commit: GitHub <[email protected]> CommitDate: Sat Mar 28 19:17:10 2020 +0100 [SDK][NDK][PSTYPES] Align the PROCESS_PRIORITY_CLASS structure during compile time (#2478) CORE-16757 After doing investigations on the priority class structure alignment, it's been revealed that in Windows XP and Server 2003 this PROCESS_PRIORITY_CLASS structure is aligned as a 4-bytes of size hence NtQueryInformationProcess() probes the alignment of user mode arguments buffer output and buffer length with requirement of a ULONG. As PROCESS_PRIORITY_CLASS was initially aligned as a 1-byte size because both BOOLEAN and UCHAR are just unsigned characters, the compiler may not align such structure and gracefully let the default alignment of such structure as is, 1-byte because an unsigned char has a size of 1 byte. Setting an align attribute to this structure fixes the problem of a potential datatype misalignment which caused GetPriorityClass() to not retrieve the process' priority class properly. --- sdk/include/ndk/pstypes.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/sdk/include/ndk/pstypes.h b/sdk/include/ndk/pstypes.h index 543afcb618d..219b880368f 100644 --- a/sdk/include/ndk/pstypes.h +++ b/sdk/include/ndk/pstypes.h @@ -902,7 +902,7 @@ typedef struct _PROCESS_SESSION_INFORMATION #endif -typedef struct _PROCESS_PRIORITY_CLASS +typedef struct DECLSPEC_ALIGN(4) _PROCESS_PRIORITY_CLASS { BOOLEAN Foreground; UCHAR PriorityClass;
