[NaCl SDK] Map active fds to absolute paths.

native_client_sdk/src/libraries/nacl_io/kernel_object.h

Index: native_client_sdk/src/libraries/nacl_io/kernel_object.h
diff --git a/native_client_sdk/src/libraries/nacl_io/kernel_object.h b/native_client_sdk/src/libraries/nacl_io/kernel_object.h
index 70ffb2f54a13e80900067f0b1845e8348be2f591..ca6be9d4e57e136d13742a609d77372d4c7c5e09 100644
--- a/native_client_sdk/src/libraries/nacl_io/kernel_object.h
+++ b/native_client_sdk/src/libraries/nacl_io/kernel_object.h
@@ -31,10 +31,13 @@ class KernelObject {
  public:
   struct Descriptor_t {
     Descriptor_t() : flags(0) {}
-    explicit Descriptor_t(const ScopedKernelHandle& h) : handle(h), flags(0) {}
+    explicit Descriptor_t(const ScopedKernelHandle& h,
+                          const std::string& open_path)
+      : handle(h), flags(0), path(open_path) {}
 
     ScopedKernelHandle handle;
     int flags;
+    std::string path;
   };
   typedef std::vector<Descriptor_t> HandleMap_t;
   typedef std::map<std::string, ScopedFilesystem> FsMap_t;
@@ -71,14 +74,18 @@ class KernelObject {
   // Convert from FD to KernelHandle, and acquire the handle.
   // Assumes |out_handle| is non-NULL.
   Error AcquireHandle(int fd, ScopedKernelHandle* out_handle);
+  Error AcquireHandleAndPath(int fd, ScopedKernelHandle *out_handle,
+                             std::string* out_path);
 
   // Allocate a new fd and assign the handle to it, while
   // ref counting the handle and associated filesystem.
   // Assumes |handle| is non-NULL;
-  int AllocateFD(const ScopedKernelHandle& handle);
+  int AllocateFD(const ScopedKernelHandle& handle,
+                 const std::string& path=std::string());
 
   // Assumes |handle| is non-NULL;
-  void FreeAndReassignFD(int fd, const ScopedKernelHandle& handle);
+  void FreeAndReassignFD(int fd, const ScopedKernelHandle& handle,
+                         const std::string& path);
   void FreeFD(int fd);
 
   // Returns or sets CWD