Pretty excited about the 32bit support! I was just kicking the tires on it
today and I realize this is still a work in progress, but I wanted to report a
possible bug with VL32/Windows.
When I open a database with MDB_RDONLY and seek a cursor to MDB_LAST, I get a
system error code of 0xc000004e (STATUS_SECTION_PROTECTION) from
NtMapViewOfSection. This is presumably because of the MEM_RESERVE_FLAG is
present on the open of the db when MDB_RDONLY is used.
After patching up the NtMapViewOfSection, I get a
0xc000001f(STATUS_INVALID_VIEW_SIZE) from NtMapViewOfSection. I believe this
happens because it is requesting a view that goes beyond the size of the db. A
quick adjustment on the “len” being requested seems to have “fixed” it.
I have included a diff patch below. I realize this is a naïve hack, but hoped
it could be useful in reproducing and fixing.
-Jer
diff --git a/src/lmdb/mdb.c b/src/lmdb/mdb.c
index 297d3e3..d594a6f 100644
--- a/src/lmdb/mdb.c
+++ b/src/lmdb/mdb.c
@@ -5655,7 +5655,7 @@ mdb_rpage_get(MDB_txn *txn, pgno_t pg0, MDB_page **ret)
#define MAP(rc,env,addr,len,off) \
addr = NULL; \
rc = NtMapViewOfSection(env->me_fmh, GetCurrentProcess(), &addr,
0, \
- len, &off, &len, ViewUnmap, MEM_RESERVE,
PAGE_READONLY)
+ len, &off, &len, ViewUnmap, ((env->me_flags &
MDB_RDONLY) == 0) ? MEM_RESERVE : 0, PAGE_READONLY)
#else
off_t off;
size_t len;
@@ -5835,6 +5835,14 @@ retry:
}
}
SET_OFF(off, pgno * env->me_psize);
+
+#ifdef MDB_VL32
+ if(off.QuadPart + len > env->me_mapsize)
+ {
+ len = env->me_mapsize - off.QuadPart;
+ }
+#endif
+
MAP(rc, env, id3.mptr, len, off);
if (rc) {
fail:
