Merge "Unlink the tombstone proto file before linking the temporary fd." (4abe7c41) · Commits · e / os / android_system_core

debuggerd/tombstoned/tombstoned.cpp

+22 −27

Original line number	Diff line number	Diff line
		@@ -408,12 +408,21 @@ static void crash_request_cb(evutil_socket_t sockfd, short ev, void* arg) {
		}
		}

		static bool link_fd(borrowed_fd fd, borrowed_fd dirfd, const std::string& path) {
		std::string fd_path = StringPrintf("/proc/self/fd/%d", fd.get());
		static bool rename_tombstone_fd(borrowed_fd fd, borrowed_fd dirfd, const std::string& path) {
		// Always try to unlink the tombstone file.
		// linkat doesn't let us replace a file, so we need to unlink before linking
		// our results onto disk, and if we fail for some reason, we should delete
		// stale tombstones to avoid confusing inconsistency.
		int rc = unlinkat(dirfd.get(), path.c_str(), 0);
		if (rc != 0 && errno != ENOENT) {
		PLOG(ERROR) << "failed to unlink tombstone at " << path;
		return false;
		}

		int rc = linkat(AT_FDCWD, fd_path.c_str(), dirfd.get(), path.c_str(), AT_SYMLINK_FOLLOW);
		std::string fd_path = StringPrintf("/proc/self/fd/%d", fd.get());
		rc = linkat(AT_FDCWD, fd_path.c_str(), dirfd.get(), path.c_str(), AT_SYMLINK_FOLLOW);
		if (rc != 0) {
		PLOG(ERROR) << "failed to link file descriptor";
		PLOG(ERROR) << "failed to link tombstone at " << path;
		return false;
		}
		return true;
		@@ -446,20 +455,7 @@ static void crash_completed(borrowed_fd sockfd, std::unique_ptr<Crash> crash) {

		CrashArtifactPaths paths = queue->get_next_artifact_paths();

		// Always try to unlink the tombstone file.
		// linkat doesn't let us replace a file, so we need to unlink before linking
		// our results onto disk, and if we fail for some reason, we should delete
		// stale tombstones to avoid confusing inconsistency.
		rc = unlinkat(queue->dir_fd().get(), paths.text.c_str(), 0);
		if (rc != 0 && errno != ENOENT) {
		PLOG(ERROR) << "failed to unlink tombstone at " << paths.text;
		return;
		}

		if (crash->output.text.fd != -1) {
		if (!link_fd(crash->output.text.fd, queue->dir_fd(), paths.text)) {
		LOG(ERROR) << "failed to link tombstone";
		} else {
		if (rename_tombstone_fd(crash->output.text.fd, queue->dir_fd(), paths.text)) {
		if (crash->crash_type == kDebuggerdJavaBacktrace) {
		LOG(ERROR) << "Traces for pid " << crash->crash_pid << " written to: " << paths.text;
		} else {
		@@ -469,13 +465,12 @@ static void crash_completed(borrowed_fd sockfd, std::unique_ptr<Crash> crash) {
		LOG(ERROR) << "Tombstone written to: " << paths.text;
		}
		}
		}

		if (crash->output.proto && crash->output.proto->fd != -1) {
		if (!paths.proto) {
		LOG(ERROR) << "missing path for proto tombstone";
		} else if (!link_fd(crash->output.proto->fd, queue->dir_fd(), *paths.proto)) {
		LOG(ERROR) << "failed to link proto tombstone";
		} else {
		rename_tombstone_fd(crash->output.proto->fd, queue->dir_fd(), *paths.proto);
		}
		}