base: add support for tagged fd closure to unique_fd.
Test: libbase_test
Change-Id: Ibba5e60d7007265a566eb8f76021d5dbeb734532
diff --git a/base/Android.bp b/base/Android.bp
index 3d80d97..46a0233 100644
--- a/base/Android.bp
+++ b/base/Android.bp
@@ -135,6 +135,7 @@
"strings_test.cpp",
"test_main.cpp",
"test_utils_test.cpp",
+ "unique_fd_test.cpp",
],
target: {
android: {
diff --git a/base/include/android-base/unique_fd.h b/base/include/android-base/unique_fd.h
index 6cfcd3f..057f462 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 @@
// 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&);
diff --git a/base/unique_fd_test.cpp b/base/unique_fd_test.cpp
new file mode 100644
index 0000000..3fdf12a
--- /dev/null
+++ b/base/unique_fd_test.cpp
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "android-base/unique_fd.h"
+
+#include <gtest/gtest.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+using android::base::unique_fd;
+
+TEST(unique_fd, unowned_close) {
+#if defined(__BIONIC__)
+ unique_fd fd(open("/dev/null", O_RDONLY));
+ EXPECT_DEATH(close(fd.get()), "incorrect tag");
+#endif
+}
+
+TEST(unique_fd, untag_on_release) {
+ unique_fd fd(open("/dev/null", O_RDONLY));
+ close(fd.release());
+}
+
+TEST(unique_fd, move) {
+ unique_fd fd(open("/dev/null", O_RDONLY));
+ unique_fd fd_moved = std::move(fd);
+ ASSERT_EQ(-1, fd.get());
+ ASSERT_GT(fd_moved.get(), -1);
+}
+
+TEST(unique_fd, unowned_close_after_move) {
+#if defined(__BIONIC__)
+ unique_fd fd(open("/dev/null", O_RDONLY));
+ unique_fd fd_moved = std::move(fd);
+ ASSERT_EQ(-1, fd.get());
+ ASSERT_GT(fd_moved.get(), -1);
+ EXPECT_DEATH(close(fd_moved.get()), "incorrect tag");
+#endif
+}