NaCl: enable meta-based validation for shared libraries.

chrome/nacl/nacl_listener.cc

Index: chrome/nacl/nacl_listener.cc
diff --git a/chrome/nacl/nacl_listener.cc b/chrome/nacl/nacl_listener.cc
index b0b27e91a461904f9d9eef84f9cba4eb338d4e08..cd7cbad3e1bf17865795413bee5d3275b16346aa 100644
--- a/chrome/nacl/nacl_listener.cc
+++ b/chrome/nacl/nacl_listener.cc
@@ -130,6 +130,34 @@ class BrowserValidationDBProxy : public NaClValidationDB {
     }
   }
 
+  virtual bool ResolveFileNonce(uint64 nonce, int32* fd,
+                                std::string* path) OVERRIDE {
+    *fd = -1;
+    *path = "";
+    if (nonce == 0) {
+      return false;
+    }
+    IPC::PlatformFileForTransit ipc_fd;
+    base::FilePath ipc_path;
+    if (!listener_->Send(new NaClProcessMsg_ResolveFileNonce(nonce, &ipc_fd,
+                                                             &ipc_path))) {
+      return false;
+    }
+    if (ipc_fd == IPC::InvalidPlatformFileForTransit()) {
+      return false;
+    }
+    base::PlatformFile handle =
+        IPC::PlatformFileForTransitToPlatformFile(ipc_fd);
+#if defined(OS_WIN)
+    // On Windows, valid handles are 32 bit unsigned integers so this is safe.
+    *fd = reinterpret_cast<uintptr_t>(handle);
+#else
+    *fd = handle;
+#endif
+    *path = ipc_path.AsUTF8Unsafe();

[Mark Seaborn, 2013/05/16 23:01:47]

Maybe comment why this is safe here, despite the name (assuming it is actually
safe?).

[Nick Bray (chromium), 2013/05/21 20:09:06]

Done.

+    return true;
+  }
+
  private:
   // The listener never dies, otherwise this might be a dangling reference.
   NaClListener* listener_;