[libcxx-commits] [PATCH] D97618: [libcxx] Avoid infinite recursion in create_directories, if the root directory doesn't exist

[Martin Storsjö via Phabricator via libcxx-commits]

mstorsjo created this revision.
mstorsjo added a reviewer: libc++.
mstorsjo requested review of this revision.
Herald added a project: libc++.
Herald added 1 blocking reviewer(s): libc++.

Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D97618

Files:
  libcxx/src/filesystem/operations.cpp
  libcxx/test/std/input.output/filesystems/fs.op.funcs/fs.op.create_directories/create_directories.pass.cpp


Index: libcxx/test/std/input.output/filesystems/fs.op.funcs/fs.op.create_directories/create_directories.pass.cpp
===================================================================
--- libcxx/test/std/input.output/filesystems/fs.op.funcs/fs.op.create_directories/create_directories.pass.cpp
+++ libcxx/test/std/input.output/filesystems/fs.op.funcs/fs.op.create_directories/create_directories.pass.cpp
@@ -138,4 +138,18 @@
     TEST_CHECK(!exists(dir));
 }
 
+#ifdef _WIN32
+TEST_CASE(nonexistent_root)
+{
+    std::error_code ec = GetTestEC();
+    // If Q:\ doesn't exist, create_directories would try to recurse upwards
+    // to parent_path() until it finds a directory that does exist. As the
+    // whole path is the root name, parent_path() returns itself, and it
+    // would recurse indefinitely, unless the recursion is broken.
+    if (!exists("Q:\\"))
+       TEST_CHECK(fs::create_directories("Q:\\", ec) == false);
+    TEST_CHECK(fs::create_directories("\\\\nonexistentserver", ec) == false);
+}
+#endif
+
 TEST_SUITE_END()
Index: libcxx/src/filesystem/operations.cpp
===================================================================
--- libcxx/src/filesystem/operations.cpp
+++ libcxx/src/filesystem/operations.cpp
@@ -1021,6 +1021,8 @@
     if (not status_known(parent_st))
       return err.report(m_ec);
     if (not exists(parent_st)) {
+      if (parent == p)
+        return err.report(errc::invalid_argument);
       __create_directories(parent, ec);
       if (ec && *ec) {
         return false;


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