Implement lstat by stat in nacl_io

As nacl_io does not support

TEST=./build_tools/build_sdk.py
TEST=./build_tools/test_sdk.py

Review URL: https://codereview.chromium.org/125693002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@243771 0039d316-1c4b-4281-b951-d872f2087c98

native_client_sdk/src/libraries/nacl_io/kernel_proxy.cc

@@ -634,8 +634,7 @@ int KernelProxy::truncate(const char* path, off_t len) {
 }
 
 int KernelProxy::lstat(const char* path, struct stat* buf) {
-  errno = ENOSYS;
-  return -1;
+  return stat(path, buf);
 }
 
 int KernelProxy::rename(const char* path, const char* newpath) {

native_client_sdk/src/tests/nacl_io_test/kernel_proxy_test.cc

@@ -416,6 +416,24 @@ TEST_F(KernelProxyTest, MemMountDup) {
   // fd, new_fd, dup_fd -> "/bar"
 }
 
+TEST_F(KernelProxyTest, Lstat) {
+  int fd = ki_open("/foo", O_CREAT | O_RDWR);
+  ASSERT_GT(fd, -1);
+  ASSERT_EQ(0, ki_mkdir("/bar", S_IREAD | S_IWRITE));
+
+  struct stat buf;
+  EXPECT_EQ(0, ki_lstat("/foo", &buf));
+  EXPECT_EQ(0, buf.st_size);
+  EXPECT_TRUE(S_ISREG(buf.st_mode));
+
+  EXPECT_EQ(0, ki_lstat("/bar", &buf));
+  EXPECT_EQ(0, buf.st_size);
+  EXPECT_TRUE(S_ISDIR(buf.st_mode));
+
+  EXPECT_EQ(-1, ki_lstat("/no-such-file", &buf));
+  EXPECT_EQ(ENOENT, errno);
+}
+
 namespace {
 
 StringMap_t g_string_map;