[NaCl SDK] Map active fds to absolute paths.

native_client_sdk/src/libraries/nacl_io/kernel_proxy.cc

 // Copyright (c) 2012 The Chromium 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 "nacl_io/kernel_proxy.h"
 
 #include <assert.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <limits.h>
@@ skipping 154 matching lines @@
     }
   }
 
   ScopedKernelHandle handle(new KernelHandle(fs, node));
   error = handle->Init(O_RDONLY);
   if (error) {
     errno = error;
     return -1;
   }
 
-  return AllocateFD(handle);
+  return AllocateFD(handle, path);
 }
 
 int KernelProxy::open(const char* path, int open_flags) {
   ScopedFilesystem fs;
   ScopedNode node;
 
   Error error = AcquireFsAndNode(path, open_flags, &fs, &node);
   if (error) {
     errno = error;
     return -1;
   }
 
   ScopedKernelHandle handle(new KernelHandle(fs, node));
   error = handle->Init(open_flags);
   if (error) {
     errno = error;
     return -1;
   }
 
-  return AllocateFD(handle);
+  return AllocateFD(handle, path);
 }
 
 int KernelProxy::pipe(int pipefds[2]) {
   PipeNode* pipe = new PipeNode(stream_mount_.get());
   ScopedNode node(pipe);
 
   if (pipe->Init(O_RDWR) == 0) {
     ScopedKernelHandle handle0(new KernelHandle(stream_mount_, node));
     ScopedKernelHandle handle1(new KernelHandle(stream_mount_, node));
 
@@ skipping 20 matching lines @@
     return -1;
   }
 
   // Remove the FD from the process open file descriptor map
   FreeFD(fd);
   return 0;
 }
 
 int KernelProxy::dup(int oldfd) {
   ScopedKernelHandle handle;
-  Error error = AcquireHandle(oldfd, &handle);
+  std::string path;
+  Error error = AcquireHandleAndPath(oldfd, &handle, &path);
   if (error) {
     errno = error;
     return -1;
   }
-
-  return AllocateFD(handle);
+  return AllocateFD(handle, path);
 }
 
 int KernelProxy::dup2(int oldfd, int newfd) {
   // If it's the same file handle, just return
   if (oldfd == newfd)
     return newfd;
 
   ScopedKernelHandle old_handle;
-  Error error = AcquireHandle(oldfd, &old_handle);
+  std::string old_path;
+  Error error = AcquireHandleAndPath(oldfd, &old_handle, &old_path);
   if (error) {
     errno = error;
     return -1;
   }
 
-  FreeAndReassignFD(newfd, old_handle);
+  FreeAndReassignFD(newfd, old_handle, old_path);
   return newfd;
 }
 
 int KernelProxy::chdir(const char* path) {
   Error error = SetCWD(path);
   if (error) {
     errno = error;
     return -1;
   }
   return 0;
@@ skipping 239 matching lines @@
 
   int cnt = 0;
   error = handle->GetDents(static_cast<dirent*>(buf), count, &cnt);
   if (error)
     errno = error;
 
   return cnt;
 }
 
 int KernelProxy::fchdir(int fd) {
-  errno = ENOSYS;
-  return -1;
+  ScopedKernelHandle handle;
+  std::string path;
+  Error error = AcquireHandleAndPath(fd, &handle, &path);
+  if (error) {
+    errno = error;
+    return -1;
+  }
+
+  if (!handle->node()->IsaDir()) {
+    errno = ENOTDIR;
+    return -1;
+  }
+
+  if (path.empty()) {
+    errno = EBADF;
+    return -1;
+  }
+
+  error = SetCWD(path);
+  if (error) {
+    // errno is return value from SetCWD
+    errno = error;
+    return -1;
+  }
+  return 0;
 }
 
 int KernelProxy::ftruncate(int fd, off_t length) {
   ScopedKernelHandle handle;
   Error error = AcquireHandle(fd, &handle);
   if (error) {
     errno = error;
     return -1;
   }
 
@@ skipping 1072 matching lines @@
     errno = ENOTSOCK;
     return -1;
   }
 
   return 0;
 }
 
 #endif  // PROVIDES_SOCKET_API
 
 }  // namespace_nacl_io