commit 43899ee8cc95620b0d93560d40899997ce3cc76d
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Wed Jan 8 16:23:07 2020 +0000

    libstdc++: Fix error handling in filesystem::remove_all (PR93201)
    
    When recursing into a directory, any errors that occur while removing a
    directory entry are ignored, because the subsequent increment of the
    directory iterator clears the error_code object.
    
    This fixes that bug by checking the result of each recursive operation
    before incrementing. This is a change in observable behaviour, because
    previously other directory entries would still be removed even if one
    (or more) couldn't be removed due to errors. Now the operation stops on
    the first error, which is what the code intended to do all along. The
    standard doesn't specify what happens in this case (because the order
    that the entries are processed is unspecified anyway).
    
            PR libstdc++/93201
            * src/c++17/fs_ops.cc (remove_all(const path&, error_code&)): Check
            result of recursive call before incrementing iterator.
            * src/filesystem/ops.cc (remove_all(const path&, error_code&)):
            Likewise.
            * testsuite/27_io/filesystem/operations/remove_all.cc: Check errors
            are reported correctly.
            * testsuite/experimental/filesystem/operations/remove_all.cc: Likewise.

diff --git a/libstdc++-v3/src/c++17/fs_ops.cc b/libstdc++-v3/src/c++17/fs_ops.cc
index d8064819d36..d918c2af530 100644
--- a/libstdc++-v3/src/c++17/fs_ops.cc
+++ b/libstdc++-v3/src/c++17/fs_ops.cc
@@ -1299,12 +1299,17 @@ fs::remove_all(const path& p, error_code& ec)
   uintmax_t count = 0;
   if (s.type() == file_type::directory)
     {
-      for (directory_iterator d(p, ec), end; !ec && d != end; d.increment(ec))
-	count += fs::remove_all(d->path(), ec);
-      if (ec.value() == ENOENT)
-	ec.clear();
-      else if (ec)
-	return -1;
+      directory_iterator d(p, ec), end;
+      while (!ec && d != end)
+	{
+	  const auto removed = fs::remove_all(d->path(), ec);
+	  if (removed == numeric_limits<uintmax_t>::max())
+	    return -1;
+	  count += removed;
+	  d.increment(ec);
+	  if (ec)
+	    return -1;
+	}
     }
 
   if (fs::remove(p, ec))
diff --git a/libstdc++-v3/src/filesystem/ops.cc b/libstdc++-v3/src/filesystem/ops.cc
index 36b5d2c24f6..a5887f37ce1 100644
--- a/libstdc++-v3/src/filesystem/ops.cc
+++ b/libstdc++-v3/src/filesystem/ops.cc
@@ -1098,12 +1098,17 @@ fs::remove_all(const path& p, error_code& ec) noexcept
   uintmax_t count = 0;
   if (s.type() == file_type::directory)
     {
-      for (directory_iterator d(p, ec), end; !ec && d != end; d.increment(ec))
-	count += fs::remove_all(d->path(), ec);
-      if (ec.value() == ENOENT)
-	ec.clear();
-      else if (ec)
-	return -1;
+      directory_iterator d(p, ec), end;
+      while (!ec && d != end)
+	{
+	  const auto removed = fs::remove_all(d->path(), ec);
+	  if (removed == numeric_limits<uintmax_t>::max())
+	    return -1;
+	  count += removed;
+	  d.increment(ec);
+	  if (ec)
+	    return -1;
+	}
     }
 
   if (fs::remove(p, ec))
diff --git a/libstdc++-v3/testsuite/27_io/filesystem/operations/remove_all.cc b/libstdc++-v3/testsuite/27_io/filesystem/operations/remove_all.cc
index a19bac9c5f6..b0b176fc656 100644
--- a/libstdc++-v3/testsuite/27_io/filesystem/operations/remove_all.cc
+++ b/libstdc++-v3/testsuite/27_io/filesystem/operations/remove_all.cc
@@ -140,10 +140,43 @@ test03()
   VERIFY( !exists(p) );
 }
 
+void
+test04()
+{
+#if defined(__MINGW32__) || defined(__MINGW64__)
+  // no permissions
+#else
+  // PR libstdc++/93201
+  std::error_code ec;
+  std::uintmax_t n;
+
+  auto dir = __gnu_test::nonexistent_path();
+  fs::create_directory(dir);
+  __gnu_test::scoped_file f(dir/"file");
+  // remove write permission on the directory:
+  fs::permissions(dir, fs::perms::owner_read|fs::perms::owner_exec);
+  n = fs::remove_all(dir, ec);
+  VERIFY( n == -1 );
+  VERIFY( ec == std::errc::permission_denied ); // not ENOTEMPTY
+
+  try {
+    fs::remove_all(dir);
+    VERIFY( false );
+  } catch (const fs::filesystem_error& e) {
+    VERIFY( e.code() == std::errc::permission_denied );
+    // First path is the argument to remove_all
+    VERIFY( e.path1() == dir );
+  }
+
+  fs::permissions(dir, fs::perms::owner_write, fs::perm_options::add);
+#endif
+}
+
 int
 main()
 {
   test01();
   test02();
   test03();
+  test04();
 }
diff --git a/libstdc++-v3/testsuite/experimental/filesystem/operations/remove_all.cc b/libstdc++-v3/testsuite/experimental/filesystem/operations/remove_all.cc
index 99fb14a71d7..9d51a66c71f 100644
--- a/libstdc++-v3/testsuite/experimental/filesystem/operations/remove_all.cc
+++ b/libstdc++-v3/testsuite/experimental/filesystem/operations/remove_all.cc
@@ -108,9 +108,42 @@ test02()
   VERIFY( !exists(dir) );
 }
 
+void
+test04()
+{
+#if defined(__MINGW32__) || defined(__MINGW64__)
+  // no permissions
+#else
+  // PR libstdc++/93201
+  std::error_code ec;
+  std::uintmax_t n;
+
+  auto dir = __gnu_test::nonexistent_path();
+  fs::create_directory(dir);
+  __gnu_test::scoped_file f(dir/"file");
+  // remove write permission on the directory:
+  fs::permissions(dir, fs::perms::owner_read|fs::perms::owner_exec);
+  n = fs::remove_all(dir, ec);
+  VERIFY( n == -1 );
+  VERIFY( ec == std::errc::permission_denied ); // not ENOTEMPTY
+
+  try {
+    fs::remove_all(dir);
+    VERIFY( false );
+  } catch (const fs::filesystem_error& e) {
+    VERIFY( e.code() == std::errc::permission_denied );
+    // First path is the argument to remove_all
+    VERIFY( e.path1() == dir );
+  }
+
+  fs::permissions(dir, fs::perms::owner_write|fs::perms::add_perms);
+#endif
+}
+
 int
 main()
 {
   test01();
   test02();
+  test04();
 }