MinSFI: Add loader

src/minsfi/trusted/entry.c

+/*
+ * Copyright (c) 2014 The Native Client Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "native_client/src/include/minsfi.h"
+#include "native_client/src/include/minsfi_priv.h"
+
+/*
+ * Fixed offset of the data segment. This must be kept in sync with the
+ * AllocateDataSegment compiler pass.
+ */
+#define DATASEG_OFFSET 0x10000
+
+/* Globals exported by the sandbox, aka the manifest. */
+extern uint32_t    __sfi_pointer_size;
+extern const char  __sfi_data_segment[];
+extern uint32_t    __sfi_data_segment_size;
+
+/* Entry point of the sandbox */
+extern int _start_minsfi(void);
+
+/*
+ * This is the global memory base variable used by the SFI sandboxing. It is
+ * a 64-bit unsigned integer on both 32-bit and 64-bit platforms.
+ */
+uint64_t __sfi_memory_base = 0;

[jvoung (off chromium), 2014/09/05 00:31:59]

Could add some emphasis that this is exported, but imported by the untrusted
code via the compiler transforms. Maybe declare as extern in the minsfi.h ?

[dbrazdil, 2014/09/05 19:41:37]

Done.

+
+static inline void get_manifest(manifest *sb) {
+  sb->ptr_size = __sfi_pointer_size;
+  sb->dataseg_offset = DATASEG_OFFSET;
+  sb->dataseg_size = __sfi_data_segment_size;
+  sb->dataseg_template = __sfi_data_segment;
+}
+
+int minsfi_exec(void) {
+  if (__sfi_memory_base == 0) {
+    char *base;
+    manifest sb;
+
+    get_manifest(&sb);
+    base = init_sandbox(&sb);
+    if (base == NULL)
+      return EXIT_FAILURE;
+
+    __sfi_memory_base = (uint64_t) ((uintptr_t) base);
+  }
+
+  return _start_minsfi();
+}
+
+bool minsfi_destroy(void) {
+  manifest sb;
+
+  if (__sfi_memory_base == 0)
+    return true;
+
+  get_manifest(&sb);
+  return destroy_sandbox((char*) ((uintptr_t) __sfi_memory_base), &sb);

[jvoung (off chromium), 2014/09/05 00:31:59]

Should this modify __sfi_memory_base back to 0 before returning?

[dbrazdil, 2014/09/05 19:41:37]

Done. Added tests which check that the base has been reset.

+}