diff --git a/debuggerd/tombstoned/tombstoned.cpp b/debuggerd/tombstoned/tombstoned.cpp index 1bf8f14d0..5dffa5b3c 100644 --- a/debuggerd/tombstoned/tombstoned.cpp +++ b/debuggerd/tombstoned/tombstoned.cpp @@ -61,10 +61,10 @@ enum CrashStatus { struct Crash { ~Crash() { event_free(crash_event); } - unique_fd crash_fd; + unique_fd crash_tombstone_fd; + unique_fd crash_socket_fd; pid_t crash_pid; event* crash_event = nullptr; - std::string crash_path; DebuggerdDumpType crash_type; }; @@ -109,24 +109,27 @@ class CrashQueue { return &queue; } - std::pair get_output() { - unique_fd result; - std::string file_name = StringPrintf("%s%02d", file_name_prefix_.c_str(), next_artifact_); - - // Unlink and create the file, instead of using O_TRUNC, to avoid two processes - // interleaving their output in case we ever get into that situation. - if (unlinkat(dir_fd_, file_name.c_str(), 0) != 0 && errno != ENOENT) { - PLOG(FATAL) << "failed to unlink tombstone at " << dir_path_ << "/" << file_name; - } - - result.reset(openat(dir_fd_, file_name.c_str(), - O_CREAT | O_EXCL | O_WRONLY | O_APPEND | O_CLOEXEC, 0640)); + unique_fd get_output() { + unique_fd result(openat(dir_fd_, ".", O_WRONLY | O_APPEND | O_TMPFILE | O_CLOEXEC, 0640)); if (result == -1) { - PLOG(FATAL) << "failed to create tombstone at " << dir_path_ << "/" << file_name; + // We might not have O_TMPFILE. Try creating and unlinking instead. + result.reset( + openat(dir_fd_, ".temporary", O_WRONLY | O_APPEND | O_CREAT | O_TRUNC | O_CLOEXEC, 0640)); + if (result == -1) { + PLOG(FATAL) << "failed to create temporary tombstone in " << dir_path_; + } + if (unlinkat(dir_fd_, ".temporary", 0) != 0) { + PLOG(FATAL) << "failed to unlink temporary tombstone"; + } } + return result; + } + std::string get_next_artifact_path() { + std::string file_name = + StringPrintf("%s/%s%02d", dir_path_.c_str(), file_name_prefix_.c_str(), next_artifact_); next_artifact_ = (next_artifact_ + 1) % max_artifacts_; - return {std::move(result), dir_path_ + "/" + file_name}; + return file_name; } bool maybe_enqueue_crash(Crash* crash) { @@ -203,14 +206,17 @@ static void crash_completed_cb(evutil_socket_t sockfd, short ev, void* arg); static void perform_request(Crash* crash) { unique_fd output_fd; - if (!intercept_manager->GetIntercept(crash->crash_pid, crash->crash_type, &output_fd)) { - std::tie(output_fd, crash->crash_path) = CrashQueue::for_crash(crash)->get_output(); + bool intercepted = + intercept_manager->GetIntercept(crash->crash_pid, crash->crash_type, &output_fd); + if (!intercepted) { + output_fd = CrashQueue::for_crash(crash)->get_output(); + crash->crash_tombstone_fd.reset(dup(output_fd.get())); } TombstonedCrashPacket response = { .packet_type = CrashPacketType::kPerformDump }; - ssize_t rc = send_fd(crash->crash_fd, &response, sizeof(response), std::move(output_fd)); + ssize_t rc = send_fd(crash->crash_socket_fd, &response, sizeof(response), std::move(output_fd)); if (rc == -1) { PLOG(WARNING) << "failed to send response to CrashRequest"; goto fail; @@ -222,7 +228,7 @@ static void perform_request(Crash* crash) { struct timeval timeout = { 10, 0 }; event_base* base = event_get_base(crash->crash_event); - event_assign(crash->crash_event, base, crash->crash_fd, EV_TIMEOUT | EV_READ, + event_assign(crash->crash_event, base, crash->crash_socket_fd, EV_TIMEOUT | EV_READ, crash_completed_cb, crash); event_add(crash->crash_event, &timeout); } @@ -243,7 +249,7 @@ static void crash_accept_cb(evconnlistener* listener, evutil_socket_t sockfd, so // and only native crashes on the native socket. struct timeval timeout = { 1, 0 }; event* crash_event = event_new(base, sockfd, EV_TIMEOUT | EV_READ, crash_request_cb, crash); - crash->crash_fd.reset(sockfd); + crash->crash_socket_fd.reset(sockfd); crash->crash_event = crash_event; event_add(crash_event, &timeout); } @@ -342,14 +348,27 @@ static void crash_completed_cb(evutil_socket_t sockfd, short ev, void* arg) { goto fail; } - if (!crash->crash_path.empty()) { - if (crash->crash_type == kDebuggerdJavaBacktrace) { - LOG(ERROR) << "Traces for pid " << crash->crash_pid << " written to: " << crash->crash_path; + if (crash->crash_tombstone_fd != -1) { + std::string fd_path = StringPrintf("/proc/self/fd/%d", crash->crash_tombstone_fd.get()); + std::string tombstone_path = CrashQueue::for_crash(crash)->get_next_artifact_path(); + int rc = unlink(tombstone_path.c_str()); + if (rc != 0) { + PLOG(ERROR) << "failed to unlink tombstone at " << tombstone_path; + goto fail; + } + + rc = linkat(AT_FDCWD, fd_path.c_str(), AT_FDCWD, tombstone_path.c_str(), AT_SYMLINK_FOLLOW); + if (rc != 0) { + PLOG(ERROR) << "failed to link tombstone"; } else { - // NOTE: Several tools parse this log message to figure out where the - // tombstone associated with a given native crash was written. Any changes - // to this message must be carefully considered. - LOG(ERROR) << "Tombstone written to: " << crash->crash_path; + if (crash->crash_type == kDebuggerdJavaBacktrace) { + LOG(ERROR) << "Traces for pid " << crash->crash_pid << " written to: " << tombstone_path; + } else { + // NOTE: Several tools parse this log message to figure out where the + // tombstone associated with a given native crash was written. Any changes + // to this message must be carefully considered. + LOG(ERROR) << "Tombstone written to: " << tombstone_path; + } } }