postgres.git / summary / log / commit / refs

commit    eda5e908291e80df9ea2ff5b6a9fd026719de2a6
Author:   Tom Lane <tgl@sss.pgh.pa.us>
Date:     Fri Sep 23 14:09:52 2016 +0000

    Don't trust CreateFileMapping() to clear the error code on success.
    
    We must test GetLastError() even when CreateFileMapping() returns a
    non-null handle.  If that value were left over from some previous system
    call, we might be fooled into thinking the segment already existed.
    Experimentation on Windows 7 suggests that CreateFileMapping() clears
    the error code on success, but it is not documented to do so, so let's
    not rely on that happening in all Windows releases.
    
    Amit Kapila
    
    Discussion: <20811.1474390987@sss.pgh.pa.us>


 src/backend/storage/ipc/dsm_impl.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/backend/storage/ipc/dsm_impl.c b/src/backend/storage/ipc/dsm_impl.c
index 72402678be0..c611ab0bafd 100644
--- a/src/backend/storage/ipc/dsm_impl.c
+++ b/src/backend/storage/ipc/dsm_impl.c
@@ -681,6 +681,9 @@ dsm_impl_windows(dsm_op op, dsm_handle handle, Size request_size,
 #endif
 		size_low = (DWORD) request_size;
 
+		/* CreateFileMapping might not clear the error code on success */
+		SetLastError(0);
+
 		hmap = CreateFileMapping(INVALID_HANDLE_VALUE,	/* Use the pagefile */
 								 NULL,	/* Default security attrs */
 								 PAGE_READWRITE,		/* Memory is read/write */


[parent: 93528f7b4141]