diff options
Diffstat (limited to 'contrib/llvm-project/libcxx/src/filesystem/operations.cpp')
-rw-r--r-- | contrib/llvm-project/libcxx/src/filesystem/operations.cpp | 107 |
1 files changed, 106 insertions, 1 deletions
diff --git a/contrib/llvm-project/libcxx/src/filesystem/operations.cpp b/contrib/llvm-project/libcxx/src/filesystem/operations.cpp index 62bcfbff097f..7aeeffaae8f3 100644 --- a/contrib/llvm-project/libcxx/src/filesystem/operations.cpp +++ b/contrib/llvm-project/libcxx/src/filesystem/operations.cpp @@ -24,9 +24,10 @@ # define NOMINMAX # include <windows.h> #else -# include <unistd.h> +# include <dirent.h> # include <sys/stat.h> # include <sys/statvfs.h> +# include <unistd.h> #endif #include <time.h> #include <fcntl.h> /* values for fchmodat */ @@ -1338,6 +1339,19 @@ bool __remove(const path& p, error_code* ec) { return true; } +// We currently have two implementations of `__remove_all`. The first one is general and +// used on platforms where we don't have access to the `openat()` family of POSIX functions. +// That implementation uses `directory_iterator`, however it is vulnerable to some race +// conditions, see https://reviews.llvm.org/D118134 for details. +// +// The second implementation is used on platforms where `openat()` & friends are available, +// and it threads file descriptors through recursive calls to avoid such race conditions. +#if defined(_LIBCPP_WIN32API) +# define REMOVE_ALL_USE_DIRECTORY_ITERATOR +#endif + +#if defined(REMOVE_ALL_USE_DIRECTORY_ITERATOR) + namespace { uintmax_t remove_all_impl(path const& p, error_code& ec) { @@ -1377,6 +1391,97 @@ uintmax_t __remove_all(const path& p, error_code* ec) { return count; } +#else // !REMOVE_ALL_USE_DIRECTORY_ITERATOR + +namespace { + +template <class Cleanup> +struct scope_exit { + explicit scope_exit(Cleanup const& cleanup) + : cleanup_(cleanup) + { } + + ~scope_exit() { cleanup_(); } + +private: + Cleanup cleanup_; +}; + +uintmax_t remove_all_impl(int parent_directory, const path& p, error_code& ec) { + // First, try to open the path as a directory. + const int options = O_CLOEXEC | O_RDONLY | O_DIRECTORY | O_NOFOLLOW; + int fd = ::openat(parent_directory, p.c_str(), options); + if (fd != -1) { + // If that worked, iterate over the contents of the directory and + // remove everything in it, recursively. + scope_exit close_fd([=] { ::close(fd); }); + DIR* stream = ::fdopendir(fd); + if (stream == nullptr) { + ec = detail::capture_errno(); + return 0; + } + scope_exit close_stream([=] { ::closedir(stream); }); + + uintmax_t count = 0; + while (true) { + auto [str, type] = detail::posix_readdir(stream, ec); + static_assert(std::is_same_v<decltype(str), std::string_view>); + if (str == "." || str == "..") { + continue; + } else if (ec || str.empty()) { + break; // we're done iterating through the directory + } else { + count += remove_all_impl(fd, str, ec); + } + } + + // Then, remove the now-empty directory itself. + if (::unlinkat(parent_directory, p.c_str(), AT_REMOVEDIR) == -1) { + ec = detail::capture_errno(); + return count; + } + + return count + 1; // the contents of the directory + the directory itself + } + + ec = detail::capture_errno(); + + // If we failed to open `p` because it didn't exist, it's not an + // error -- it might have moved or have been deleted already. + if (ec == errc::no_such_file_or_directory) { + ec.clear(); + return 0; + } + + // If opening `p` failed because it wasn't a directory, remove it as + // a normal file instead. Note that `openat()` can return either ENOTDIR + // or ELOOP depending on the exact reason of the failure. + if (ec == errc::not_a_directory || ec == errc::too_many_symbolic_link_levels) { + ec.clear(); + if (::unlinkat(parent_directory, p.c_str(), /* flags = */0) == -1) { + ec = detail::capture_errno(); + return 0; + } + return 1; + } + + // Otherwise, it's a real error -- we don't remove anything. + return 0; +} + +} // end namespace + +uintmax_t __remove_all(const path& p, error_code* ec) { + ErrorHandler<uintmax_t> err("remove_all", ec, &p); + error_code mec; + uintmax_t count = remove_all_impl(AT_FDCWD, p, mec); + if (mec) + return err.report(mec); + return count; +} + +#endif // REMOVE_ALL_USE_DIRECTORY_ITERATOR + void __rename(const path& from, const path& to, error_code* ec) { ErrorHandler<void> err("rename", ec, &from, &to); if (detail::rename(from.c_str(), to.c_str()) == -1) |