From cbe70cb0a8cb0171f3802273050e851a47b090ed Mon Sep 17 00:00:00 2001
From: Josh Gao <jmgao@google.com>
Date: Tue, 18 Oct 2016 18:17:52 -0700
Subject: debuggerd: advance our amazing bet.

Remove debuggerd in favor of a helper process that gets execed by
crashing processes.

Bug: http://b/30705528
Test: debuggerd_test
Change-Id: I9906c69473989cbf7fe5ea6cccf9a9c563d75906
---
 debuggerd/util.cpp | 96 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 96 insertions(+)
 create mode 100644 debuggerd/util.cpp

(limited to 'debuggerd/util.cpp')

diff --git a/debuggerd/util.cpp b/debuggerd/util.cpp
new file mode 100644
index 000000000..738abdf7b
--- /dev/null
+++ b/debuggerd/util.cpp
@@ -0,0 +1,96 @@
+/*
+ * Copyright 2016, 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/util.h"
+
+#include <sys/socket.h>
+
+#include <utility>
+
+#include <android-base/unique_fd.h>
+#include <cutils/sockets.h>
+
+ssize_t send_fd(int sockfd, const void* data, size_t len, android::base::unique_fd fd) {
+  char cmsg_buf[CMSG_SPACE(sizeof(int))];
+
+  iovec iov = { .iov_base = const_cast<void*>(data), .iov_len = len };
+  msghdr msg = {
+    .msg_iov = &iov, .msg_iovlen = 1, .msg_control = cmsg_buf, .msg_controllen = sizeof(cmsg_buf),
+  };
+  auto cmsg = CMSG_FIRSTHDR(&msg);
+  cmsg->cmsg_level = SOL_SOCKET;
+  cmsg->cmsg_type = SCM_RIGHTS;
+  cmsg->cmsg_len = CMSG_LEN(sizeof(int));
+  *reinterpret_cast<int*>(CMSG_DATA(cmsg)) = fd.get();
+
+  return TEMP_FAILURE_RETRY(sendmsg(sockfd, &msg, 0));
+}
+
+ssize_t recv_fd(int sockfd, void* _Nonnull data, size_t len,
+                android::base::unique_fd* _Nullable out_fd) {
+  char cmsg_buf[CMSG_SPACE(sizeof(int))];
+
+  iovec iov = { .iov_base = const_cast<void*>(data), .iov_len = len };
+  msghdr msg = {
+    .msg_iov = &iov,
+    .msg_iovlen = 1,
+    .msg_control = cmsg_buf,
+    .msg_controllen = sizeof(cmsg_buf),
+    .msg_flags = 0,
+  };
+  auto cmsg = CMSG_FIRSTHDR(&msg);
+  cmsg->cmsg_level = SOL_SOCKET;
+  cmsg->cmsg_type = SCM_RIGHTS;
+  cmsg->cmsg_len = CMSG_LEN(sizeof(int));
+
+  ssize_t result = TEMP_FAILURE_RETRY(recvmsg(sockfd, &msg, 0));
+  if (result == -1) {
+    return -1;
+  }
+
+  android::base::unique_fd fd;
+  bool received_fd = msg.msg_controllen == sizeof(cmsg_buf);
+  if (received_fd) {
+    fd.reset(*reinterpret_cast<int*>(CMSG_DATA(cmsg)));
+  }
+
+  if ((msg.msg_flags & MSG_TRUNC) != 0) {
+    errno = EFBIG;
+    return -1;
+  } else if ((msg.msg_flags & MSG_CTRUNC) != 0) {
+    errno = ERANGE;
+    return -1;
+  }
+
+  if (out_fd) {
+    *out_fd = std::move(fd);
+  } else if (received_fd) {
+    errno = ERANGE;
+    return -1;
+  }
+
+  return result;
+}
+
+bool Pipe(android::base::unique_fd* read, android::base::unique_fd* write) {
+  int pipefds[2];
+  if (pipe(pipefds) != 0) {
+    return false;
+  }
+  read->reset(pipefds[0]);
+  write->reset(pipefds[1]);
+  return true;
+}
-- 
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