libstdc++: Fix unnecessary allocations in read_symlink [PR 96484]

libstdc++-v3/ChangeLog:

	PR libstdc++/96484
	* src/c++17/fs_ops.cc (fs::read_symlink): Return an error
	immediately for non-symlinks.
	* src/filesystem/ops.cc (fs::read_symlink): Likewise.

diff --git a/libstdc++-v3/src/c++17/fs_ops.cc b/libstdc++-v3/src/c++17/fs_ops.cc
index 873f93aacfc4cf5eebd3ec02df3cd0d113a0ad1a..c685b1824f9d67403fd332b5cfb7fc09874d0d01 100644 (file)
--- a/libstdc++-v3/src/c++17/fs_ops.cc
+++ b/libstdc++-v3/src/c++17/fs_ops.cc
@@ -1180,6 +1180,12 @@ fs::path fs::read_symlink(const path& p, error_code& ec)
       ec.assign(errno, std::generic_category());
       return result;
     }
+  else if (!fs::is_symlink(make_file_status(st)))
+    {
+      ec.assign(EINVAL, std::generic_category());
+      return result;
+    }
+
   std::string buf(st.st_size ? st.st_size + 1 : 128, '\0');
   do
     {

diff --git a/libstdc++-v3/src/filesystem/ops.cc b/libstdc++-v3/src/filesystem/ops.cc
index 29ea9c0ce87536655bf66d614f7552d50982cd4a..8c8854bf28e8958d9f8c8dc4d1b657146dafca2d 100644 (file)
--- a/libstdc++-v3/src/filesystem/ops.cc
+++ b/libstdc++-v3/src/filesystem/ops.cc
@@ -998,6 +998,12 @@ fs::path fs::read_symlink(const path& p [[gnu::unused]], error_code& ec)
       ec.assign(errno, std::generic_category());
       return result;
     }
+  else if (!fs::is_symlink(make_file_status(st)))
+    {
+      ec.assign(EINVAL, std::generic_category());
+      return result;
+    }
+
   std::string buf(st.st_size ? st.st_size + 1 : 128, '\0');
   do
     {