[NaCl SDK] Never return st_size == 0 for directory nodes

The scandir code in newlib assumes that st_size of
direcoties is a reflection of the number of entries,
and in particular has a early out when st_size == 0.

Review URL: https://codereview.chromium.org/1304983004

Cr-Commit-Position: refs/heads/master@{#344986}

2 files changed, 17 insertions, 8 deletions

diff --git a/native_client_sdk/src/libraries/nacl_io/html5fs/html5_fs_node.cc b/native_client_sdk/src/libraries/nacl_io/html5fs/html5_fs_node.cc
index 76eff01..bb3a8f5 100644
--- a/native_client_sdk/src/libraries/nacl_io/html5fs/html5_fs_node.cc
+++ b/native_client_sdk/src/libraries/nacl_io/html5fs/html5_fs_node.cc
@@ -26,8 +26,6 @@ namespace nacl_io {
 
 namespace {
 
-const int kEmptyDirSize = 4096;
-
 struct OutputBuffer {
   void* data;
   int element_count;
@@ -158,8 +156,6 @@ Error Html5FsNode::GetStat(struct stat* stat) {
   // Fill in known info here.
   memcpy(stat, &stat_, sizeof(stat_));
 
-  stat->st_size = static_cast<off_t>(info.size);
-
   // Fill in the additional info from ppapi.
   switch (info.type) {
     case PP_FILETYPE_REGULAR:
@@ -167,15 +163,12 @@ Error Html5FsNode::GetStat(struct stat* stat) {
       break;
     case PP_FILETYPE_DIRECTORY:
       stat->st_mode |= S_IFDIR;
-      // Hack the directory size
-      // In Linux, even a empty directory has size 4096
-      // info.size is always zero for directories
-      stat->st_size = kEmptyDirSize;
       break;
     case PP_FILETYPE_OTHER:
     default:
       break;
   }
+  stat->st_size = static_cast<off_t>(info.size);
   stat->st_atime = info.last_access_time;
   stat->st_mtime = info.last_modified_time;
   stat->st_ctime = info.creation_time;
diff --git a/native_client_sdk/src/libraries/nacl_io/kernel_proxy.cc b/native_client_sdk/src/libraries/nacl_io/kernel_proxy.cc
index de94f27..b554ade 100644
--- a/native_client_sdk/src/libraries/nacl_io/kernel_proxy.cc
+++ b/native_client_sdk/src/libraries/nacl_io/kernel_proxy.cc
@@ -422,6 +422,14 @@ int KernelProxy::stat(const char* path, struct stat* buf) {
     return -1;
   }
 
+  /*
+   * newlib's scandir() assumes that directories are empty if st_size == 0.
+   * This is probably a bad assumption, but until we fix newlib always return
+   * a non-zero directory size.
+   */
+  if (node->IsaDir() && buf->st_size == 0)
+    buf->st_size = 4096;
+
   return 0;
 }
 
@@ -588,6 +596,14 @@ int KernelProxy::fstat(int fd, struct stat* buf) {
     return -1;
   }
 
+  /*
+   * newlib's scandir() assumes that directories are empty if st_size == 0.
+   * This is probably a bad assumption, but until we fix newlib always return
+   * a non-zero directory size.
+   */
+  if (handle->node()->IsaDir() && buf->st_size == 0)
+    buf->st_size = 4096;
+
   return 0;
 }