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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2016-09-23 10:09:52 -0400 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2016-09-23 10:09:52 -0400 |
| commit | e7f5d8ea1c75cc341a966897760a812e437c4668 (patch) | |
| tree | abddd5fc41bb6d5677a95e011795ae2a1f0396f5 | |
| parent | b251379fb44b4893624999f1ba00986c029f11cf (diff) | |
| download | postgresql-e7f5d8ea1c75cc341a966897760a812e437c4668.tar.gz postgresql-e7f5d8ea1c75cc341a966897760a812e437c4668.zip | |
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>
| -rw-r--r-- | src/backend/storage/ipc/dsm_impl.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/src/backend/storage/ipc/dsm_impl.c b/src/backend/storage/ipc/dsm_impl.c index 9cc9c5d2c29..8c706aee002 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 */ |