diff options
Diffstat (limited to 'base/include')
-rw-r--r-- | base/include/android-base/unique_fd.h | 82 |
1 files changed, 68 insertions, 14 deletions
diff --git a/base/include/android-base/unique_fd.h b/base/include/android-base/unique_fd.h index 6cfcd3fb0..057f462e5 100644 --- a/base/include/android-base/unique_fd.h +++ b/base/include/android-base/unique_fd.h @@ -42,10 +42,29 @@ // // unique_fd is also known as ScopedFd/ScopedFD/scoped_fd; mentioned here to help // you find this class if you're searching for one of those names. + +#if defined(__BIONIC__) +#include <android/fdsan.h> +#endif + namespace android { namespace base { struct DefaultCloser { +#if defined(__BIONIC__) + static void Tag(int fd, void* old_addr, void* new_addr) { + uint64_t old_tag = android_fdsan_create_owner_tag(ANDROID_FDSAN_OWNER_TYPE_UNIQUE_FD, + reinterpret_cast<uint64_t>(old_addr)); + uint64_t new_tag = android_fdsan_create_owner_tag(ANDROID_FDSAN_OWNER_TYPE_UNIQUE_FD, + reinterpret_cast<uint64_t>(new_addr)); + android_fdsan_exchange_owner_tag(fd, old_tag, new_tag); + } + static void Close(int fd, void* addr) { + uint64_t tag = android_fdsan_create_owner_tag(ANDROID_FDSAN_OWNER_TYPE_UNIQUE_FD, + reinterpret_cast<uint64_t>(addr)); + android_fdsan_close_with_tag(fd, tag); + } +#else static void Close(int fd) { // Even if close(2) fails with EINTR, the fd will have been closed. // Using TEMP_FAILURE_RETRY will either lead to EBADF or closing someone @@ -53,40 +72,75 @@ struct DefaultCloser { // http://lkml.indiana.edu/hypermail/linux/kernel/0509.1/0877.html ::close(fd); } +#endif }; template <typename Closer> class unique_fd_impl final { public: - unique_fd_impl() : value_(-1) {} + unique_fd_impl() {} - explicit unique_fd_impl(int value) : value_(value) {} + explicit unique_fd_impl(int fd) { reset(fd); } ~unique_fd_impl() { reset(); } - unique_fd_impl(unique_fd_impl&& other) : value_(other.release()) {} + unique_fd_impl(unique_fd_impl&& other) { reset(other.release()); } unique_fd_impl& operator=(unique_fd_impl&& s) { - reset(s.release()); + int fd = s.fd_; + s.fd_ = -1; + reset(fd, &s); return *this; } - void reset(int new_value = -1) { - if (value_ != -1) { - Closer::Close(value_); - } - value_ = new_value; - } + void reset(int new_value = -1) { reset(new_value, nullptr); } - int get() const { return value_; } + int get() const { return fd_; } operator int() const { return get(); } int release() __attribute__((warn_unused_result)) { - int ret = value_; - value_ = -1; + tag(fd_, this, nullptr); + int ret = fd_; + fd_ = -1; return ret; } private: - int value_; + void reset(int new_value, void* previous_tag) { + if (fd_ != -1) { + close(fd_, this); + } + + fd_ = new_value; + if (new_value != -1) { + tag(new_value, previous_tag, this); + } + } + + int fd_ = -1; + + // Template magic to use Closer::Tag if available, and do nothing if not. + // If Closer::Tag exists, this implementation is preferred, because int is a better match. + // If not, this implementation is SFINAEd away, and the no-op below is the only one that exists. + template <typename T = Closer> + static auto tag(int fd, void* old_tag, void* new_tag) + -> decltype(T::Tag(fd, old_tag, new_tag), void()) { + T::Tag(fd, old_tag, new_tag); + } + + template <typename T = Closer> + static void tag(long, void*, void*) { + // No-op. + } + + // Same as above, to select between Closer::Close(int) and Closer::Close(int, void*). + template <typename T = Closer> + static auto close(int fd, void* tag_value) -> decltype(T::Close(fd, tag_value), void()) { + T::Close(fd, tag_value); + } + + template <typename T = Closer> + static auto close(int fd, void*) -> decltype(T::Close(fd), void()) { + T::Close(fd); + } unique_fd_impl(const unique_fd_impl&); void operator=(const unique_fd_impl&); |