debuggerd_handler: implement missing fallback functionality.
Allow the fallback implementation to dump traces and create tombstones
in seccomped processes.
Bug: http://b/35858739
Test: debuggerd -b `pidof media.codec`; killall -ABRT media.codec
Change-Id: I381b283de39a66d8900f1c320d32497d6f2b4ec4
diff --git a/debuggerd/tombstoned_client.cpp b/debuggerd/tombstoned_client.cpp
new file mode 100644
index 0000000..03b4a20
--- /dev/null
+++ b/debuggerd/tombstoned_client.cpp
@@ -0,0 +1,86 @@
+/*
+ * Copyright 2017, 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 "debuggerd/tombstoned.h"
+
+#include <fcntl.h>
+#include <unistd.h>
+
+#include <utility>
+
+#include <android-base/unique_fd.h>
+#include <cutils/sockets.h>
+
+#include "debuggerd/protocol.h"
+#include "debuggerd/util.h"
+#include "private/libc_logging.h"
+
+using android::base::unique_fd;
+
+bool tombstoned_connect(pid_t pid, unique_fd* tombstoned_socket, unique_fd* output_fd) {
+ unique_fd sockfd(socket_local_client(kTombstonedCrashSocketName,
+ ANDROID_SOCKET_NAMESPACE_RESERVED, SOCK_SEQPACKET));
+ if (sockfd == -1) {
+ __libc_format_log(ANDROID_LOG_ERROR, "libc", "failed to connect to tombstoned: %s",
+ strerror(errno));
+ return false;
+ }
+
+ TombstonedCrashPacket packet = {};
+ packet.packet_type = CrashPacketType::kDumpRequest;
+ packet.packet.dump_request.pid = pid;
+ if (TEMP_FAILURE_RETRY(write(sockfd, &packet, sizeof(packet))) != sizeof(packet)) {
+ __libc_format_log(ANDROID_LOG_ERROR, "libc", "failed to write DumpRequest packet: %s",
+ strerror(errno));
+ return false;
+ }
+
+ unique_fd tmp_output_fd;
+ ssize_t rc = recv_fd(sockfd, &packet, sizeof(packet), &tmp_output_fd);
+ if (rc == -1) {
+ __libc_format_log(ANDROID_LOG_ERROR, "libc",
+ "failed to read response to DumpRequest packet: %s", strerror(errno));
+ return false;
+ } else if (rc != sizeof(packet)) {
+ __libc_format_log(
+ ANDROID_LOG_ERROR, "libc",
+ "received DumpRequest response packet of incorrect length (expected %zu, got %zd)",
+ sizeof(packet), rc);
+ return false;
+ }
+
+ // Make the fd O_APPEND so that our output is guaranteed to be at the end of a file.
+ // (This also makes selinux rules consistent, because selinux distinguishes between writing to
+ // a regular fd, and writing to an fd with O_APPEND).
+ int flags = fcntl(tmp_output_fd.get(), F_GETFL);
+ if (fcntl(tmp_output_fd.get(), F_SETFL, flags | O_APPEND) != 0) {
+ __libc_format_log(ANDROID_LOG_WARN, "libc", "failed to set output fd flags: %s",
+ strerror(errno));
+ }
+
+ *tombstoned_socket = std::move(sockfd);
+ *output_fd = std::move(tmp_output_fd);
+ return true;
+}
+
+bool tombstoned_notify_completion(int tombstoned_socket) {
+ TombstonedCrashPacket packet = {};
+ packet.packet_type = CrashPacketType::kCompletedDump;
+ if (TEMP_FAILURE_RETRY(write(tombstoned_socket, &packet, sizeof(packet))) != sizeof(packet)) {
+ return false;
+ }
+ return true;
+}