diff --git a/libclamav/scanners.c b/libclamav/scanners.c
index 2b709324a..3bdd11bab 100644
--- a/libclamav/scanners.c
+++ b/libclamav/scanners.c
@@ -3476,9 +3476,25 @@ static int scan_common(int desc, cl_fmap_t *map, const char **virname, unsigned
                     rc = CL_EMEM;
                 }
                 else {
-                    cli_bytecode_context_setctx(bc_ctx, &ctx);
-                    rc = cli_bytecode_runhook(&ctx, ctx.engine, bc_ctx, BC_PRECLASS, map);
-                    cli_bytecode_context_destroy(bc_ctx);
+                    fmap_t *pc_map = map;
+
+                    if (!pc_map) {
+                        perf_start(&ctx, PERFT_MAP);
+                        if(!(pc_map = fmap(desc, 0, sb.st_size))) {
+                            perf_stop(&ctx, PERFT_MAP);
+                            rc = CL_EMEM;
+                        }
+                        perf_stop(&ctx, PERFT_MAP);
+                    }
+
+                    if (pc_map) {
+                        cli_bytecode_context_setctx(bc_ctx, &ctx);
+                        rc = cli_bytecode_runhook(&ctx, ctx.engine, bc_ctx, BC_PRECLASS, pc_map);
+                        cli_bytecode_context_destroy(bc_ctx);
+
+                        if (!map)
+                            funmap(pc_map);
+                    }
                 }
                 //ctx.options &= ~CL_SCAN_FILE_PROPERTIES;
                 //rc = cli_mem_scandesc(jstring, strlen(jstring), &ctx);