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/libdebuggerd/backtrace.cpp | 119 +++++++++++++++++++++++++++++++++++
 1 file changed, 119 insertions(+)
 create mode 100644 debuggerd/libdebuggerd/backtrace.cpp

(limited to 'debuggerd/libdebuggerd/backtrace.cpp')

diff --git a/debuggerd/libdebuggerd/backtrace.cpp b/debuggerd/libdebuggerd/backtrace.cpp
new file mode 100644
index 000000000..066444242
--- /dev/null
+++ b/debuggerd/libdebuggerd/backtrace.cpp
@@ -0,0 +1,119 @@
+/*
+ * Copyright (C) 2012 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.
+ */
+
+#define LOG_TAG "DEBUG"
+
+#include <errno.h>
+#include <dirent.h>
+#include <limits.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ptrace.h>
+#include <sys/types.h>
+#include <time.h>
+#include <unistd.h>
+
+#include <memory>
+#include <string>
+
+#include <backtrace/Backtrace.h>
+#include <log/log.h>
+
+#include "backtrace.h"
+
+#include "utility.h"
+
+static void dump_process_header(log_t* log, pid_t pid) {
+  char path[PATH_MAX];
+  char procnamebuf[1024];
+  char* procname = NULL;
+  FILE* fp;
+
+  snprintf(path, sizeof(path), "/proc/%d/cmdline", pid);
+  if ((fp = fopen(path, "r"))) {
+    procname = fgets(procnamebuf, sizeof(procnamebuf), fp);
+    fclose(fp);
+  }
+
+  time_t t = time(NULL);
+  struct tm tm;
+  localtime_r(&t, &tm);
+  char timestr[64];
+  strftime(timestr, sizeof(timestr), "%F %T", &tm);
+  _LOG(log, logtype::BACKTRACE, "\n\n----- pid %d at %s -----\n", pid, timestr);
+
+  if (procname) {
+    _LOG(log, logtype::BACKTRACE, "Cmd line: %s\n", procname);
+  }
+  _LOG(log, logtype::BACKTRACE, "ABI: '%s'\n", ABI_STRING);
+}
+
+static void dump_process_footer(log_t* log, pid_t pid) {
+  _LOG(log, logtype::BACKTRACE, "\n----- end %d -----\n", pid);
+}
+
+static void dump_thread(log_t* log, BacktraceMap* map, pid_t pid, pid_t tid) {
+  char path[PATH_MAX];
+  char threadnamebuf[1024];
+  char* threadname = NULL;
+  FILE* fp;
+
+  snprintf(path, sizeof(path), "/proc/%d/comm", tid);
+  if ((fp = fopen(path, "r"))) {
+    threadname = fgets(threadnamebuf, sizeof(threadnamebuf), fp);
+    fclose(fp);
+    if (threadname) {
+      size_t len = strlen(threadname);
+      if (len && threadname[len - 1] == '\n') {
+          threadname[len - 1] = '\0';
+      }
+    }
+  }
+
+  _LOG(log, logtype::BACKTRACE, "\n\"%s\" sysTid=%d\n", threadname ? threadname : "<unknown>", tid);
+
+  std::unique_ptr<Backtrace> backtrace(Backtrace::Create(pid, tid, map));
+  if (backtrace->Unwind(0)) {
+    dump_backtrace_to_log(backtrace.get(), log, "  ");
+  } else {
+    ALOGE("Unwind failed: tid = %d: %s", tid,
+          backtrace->GetErrorString(backtrace->GetError()).c_str());
+  }
+}
+
+void dump_backtrace(int fd, BacktraceMap* map, pid_t pid, pid_t tid,
+                    const std::set<pid_t>& siblings, std::string* amfd_data) {
+  log_t log;
+  log.tfd = fd;
+  log.amfd_data = amfd_data;
+
+  dump_process_header(&log, pid);
+  dump_thread(&log, map, pid, tid);
+
+  for (pid_t sibling : siblings) {
+    dump_thread(&log, map, pid, sibling);
+  }
+
+  dump_process_footer(&log, pid);
+}
+
+void dump_backtrace_to_log(Backtrace* backtrace, log_t* log, const char* prefix) {
+  for (size_t i = 0; i < backtrace->NumFrames(); i++) {
+    _LOG(log, logtype::BACKTRACE, "%s%s\n", prefix, backtrace->FormatFrameData(i).c_str());
+  }
+}
-- 
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