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 <[email protected]> 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(); }
