From 46756821c4fe238f12a6e5ea18c356398f8d8795 Mon Sep 17 00:00:00 2001
From: Christopher Ferris <cferris@google.com>
Date: Tue, 14 Jan 2014 20:16:30 -0800
Subject: Rewrite libbacktrace to be all C++.

This includes removing the map_info.c source and replacing it with the
BacktraceMap class to handle all map related code.

Change all callers of libbacktrace map functionality.

Also modify the corkscrew thread code so that it doesn't need to build
the map twice (once in the corkscrew format and once in the libbacktrace
format).

Change-Id: I32865a39f83a3dd6f958fc03c2759ba47d12382e
---
 libbacktrace/BacktraceMap.cpp | 130 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 130 insertions(+)
 create mode 100644 libbacktrace/BacktraceMap.cpp

(limited to 'libbacktrace/BacktraceMap.cpp')

diff --git a/libbacktrace/BacktraceMap.cpp b/libbacktrace/BacktraceMap.cpp
new file mode 100644
index 0000000..b3b4300
--- /dev/null
+++ b/libbacktrace/BacktraceMap.cpp
@@ -0,0 +1,130 @@
+/*
+ * Copyright (C) 2014 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 <ctype.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <string>
+#include <vector>
+
+#include <backtrace/BacktraceMap.h>
+#include <log/log.h>
+
+BacktraceMap::BacktraceMap(pid_t pid) : pid_(pid) {
+  if (pid_ < 0) {
+    pid_ = getpid();
+  }
+}
+
+BacktraceMap::~BacktraceMap() {
+}
+
+const backtrace_map_t* BacktraceMap::Find(uintptr_t addr) {
+  for (BacktraceMap::const_iterator it = begin();
+       it != end(); ++it) {
+    if (addr >= it->start && addr < it->end) {
+      return &*it;
+    }
+  }
+  return NULL;
+}
+
+bool BacktraceMap::ParseLine(const char* line, backtrace_map_t* map) {
+  unsigned long int start;
+  unsigned long int end;
+  char permissions[5];
+  int name_pos;
+
+#if defined(__APPLE__)
+// Mac OS vmmap(1) output:
+// __TEXT                 0009f000-000a1000 [    8K     8K] r-x/rwx SM=COW  /Volumes/android/dalvik-dev/out/host/darwin-x86/bin/libcorkscrew_test\n
+// 012345678901234567890123456789012345678901234567890123456789
+// 0         1         2         3         4         5
+  if (sscanf(line, "%*21c %lx-%lx [%*13c] %3c/%*3c SM=%*3c  %n",
+             &start, &end, permissions, &name_pos) != 3) {
+#else
+// Linux /proc/<pid>/maps lines:
+// 6f000000-6f01e000 rwxp 00000000 00:0c 16389419   /system/lib/libcomposer.so\n
+// 012345678901234567890123456789012345678901234567890123456789
+// 0         1         2         3         4         5
+  if (sscanf(line, "%lx-%lx %4s %*x %*x:%*x %*d%n",
+             &start, &end, permissions, &name_pos) != 3) {
+#endif
+    return false;
+  }
+
+  map->start = start;
+  map->end = end;
+  map->flags = PROT_NONE;
+  if (permissions[0] == 'r') {
+    map->flags |= PROT_READ;
+  }
+  if (permissions[1] == 'w') {
+    map->flags |= PROT_WRITE;
+  }
+  if (permissions[2] == 'x') {
+    map->flags |= PROT_EXEC;
+  }
+
+  while (isspace(line[name_pos])) {
+    name_pos += 1;
+  }
+  map->name = line+name_pos;
+  if (!map->name.empty() && map->name[map->name.length()-1] == '\n') {
+    map->name.erase(map->name.length()-1);
+  }
+
+  ALOGV("Parsed map: start=%p, end=%p, flags=%x, name=%s",
+        map->start, map->end, map->flags, map->name.c_str());
+  return true;
+}
+
+bool BacktraceMap::Build() {
+#if defined(__APPLE__)
+  char cmd[sizeof(pid_t)*3 + sizeof("vmmap -w -resident -submap -allSplitLibs -interleaved ") + 1];
+#else
+  char path[sizeof(pid_t)*3 + sizeof("/proc//maps") + 1];
+#endif
+  char line[1024];
+
+#if defined(__APPLE__)
+  // cmd is guaranteed to always be big enough to hold this string.
+  sprintf(cmd, "vmmap -w -resident -submap -allSplitLibs -interleaved %d", pid);
+  FILE* fp = popen(cmd, "r");
+#else
+  // path is guaranteed to always be big enough to hold this string.
+  sprintf(path, "/proc/%d/maps", pid_);
+  FILE* fp = fopen(path, "r");
+#endif
+  if (fp == NULL) {
+    return false;
+  }
+
+  while(fgets(line, sizeof(line), fp)) {
+    backtrace_map_t map;
+    if (ParseLine(line, &map)) {
+      maps_.push_back(map);
+    }
+  }
+#if defined(__APPLE__)
+  pclose(fp);
+#else
+  fclose(fp);
+#endif
+
+  return true;
+}
-- 
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