Handle ReadFile() EOF correctly on Windows.

When ReadFile() encounters the end of a file while reading from
a synchronous handle with an offset provided via OVERLAPPED, it
reports an error instead of returning 0.  By not handling that
(undocumented) result correctly, we caused some noisy LOG
messages about an unknown error code.  Repair.

Back-patch to 12, where we started using pread()/ReadFile() with
an offset.

Reported-by: ZhenHua Cai, Amit Kapila
Diagnosed-by: Juan Jose Santamaria Flecha
Tested-by: Amit Kapila
Discussion: https://postgr.es/m/CAA4eK1LK3%2BWRtpz68TiRdpHwxxWm%3D%2Bt1BMf-G68hhQsAQ41PZg%40mail.gmail.com
This commit is contained in:
Thomas Munro 2019-11-20 17:52:15 +13:00
parent 80e05a088e
commit 6969deeb8d
1 changed files with 3 additions and 0 deletions

View File

@ -41,6 +41,9 @@ pg_pread(int fd, void *buf, size_t size, off_t offset)
overlapped.Offset = offset;
if (!ReadFile(handle, buf, size, &result, &overlapped))
{
if (GetLastError() == ERROR_HANDLE_EOF)
return 0;
_dosmaperr(GetLastError());
return -1;
}