On 08/01/20 16:44 +0000, Jonathan Wakely wrote:
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).
It also improves the error reporting so that the name of the file that
could not be removed is included in the filesystem_error exception. This
is done by introducing a new helper type for reporting errors with
additional context and a new function that uses that type. Then the
overload of std::filesystem::remove_all that throws an exception can use
the new function to ensure any exception contains the additional
information.
For std::experimental::filesystem::remove_all just fix the bug where
errors are ignored.
PR libstdc++/93201
* src/c++17/fs_ops.cc (do_remove_all): New function implementing more
detailed error reporting for remove_all. Check result of recursive
call before incrementing iterator.
(remove_all(const path&), remove_all(const path&, error_code&)): Use
do_remove_all.
* src/filesystem/ops.cc (remove_all(const path&, error_code&)): Check
result of recursive call before incrementing iterator.
* testsuite/27_io/filesystem/operations/remove_all.cc: Check errors
are reported correctly.
* testsuite/experimental/filesystem/operations/remove_all.cc: Likewise.
This is what I plan to commit to the branches. It doesn't improve the
error reporting, just fixes the bug. But that *does* still change the
observable behaviour when an error occurs (because now we return
immediately on the first error, instead of continuing to remove as
much as possible).
I've sent an email to the Library Evolution list to discuss the
desired behaviour. Does anybody here have an opinion? Should we
preserve the existing "keep going then report errors at the end"
behaviour for the branches, or just make this change?
commit 43899ee8cc95620b0d93560d40899997ce3cc76d
Author: Jonathan Wakely <jwak...@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();
}
