MDB_VL32 - fix for Win32 read-only envs

We can't map with MEM_RESERVE because that requires write access
to the underlying file/section. Mapping with the default (MEM_COMMIT)
requires that we don't map past the end of the file.

diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c
index 698797f..516e69a 100644 (file)
--- a/libraries/liblmdb/mdb.c
+++ b/libraries/liblmdb/mdb.c
@@ -5689,7 +5689,7 @@ 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, PAGE_READONLY)
 #else
        off_t off;
        size_t len;
@@ -5803,9 +5803,13 @@ retry:
                id3.mref = 1;
                if (id3.mid)
                        goto found;
-               len = env->me_psize * MDB_RPAGE_CHUNK;
+               /* don't map past last written page */
+               if (pgno + MDB_RPAGE_CHUNK-1 > txn->mt_last_pgno)
+                       id3.mcnt = txn->mt_last_pgno + 1 - pgno;
+               else
+                       id3.mcnt = MDB_RPAGE_CHUNK;
+               len = id3.mcnt * env->me_psize;
                id3.mid = pgno;
-               id3.mcnt = MDB_RPAGE_CHUNK;
 
                /* search for page in env */
                LOCK_MUTEX0(env->me_rpmutex);