Add support for Linux memory mapping stream and remove ELF header usage

src/processor/proc_maps_linux.cc

+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "google_breakpad/processor/proc_maps_linux.h"
+
+#include <fcntl.h>
+#include <stdio.h>
+
+#if defined(OS_LINUX) || defined(OS_ANDROID)
+#include <inttypes.h>
+#endif
+
+#include "processor/logging.h"
+
+#if defined(OS_ANDROID) && !defined(__LP64__)
+// In 32-bit mode, Bionic's inttypes.h defines PRI/SCNxPTR as an
+// unsigned long int, which is incompatible with Bionic's stdint.h
+// defining uintptr_t as an unsigned int:
+// https://code.google.com/p/android/issues/detail?id=57218
+#undef SCNxPTR
+#define SCNxPTR "x"
+#endif
+
+bool ParseProcMaps(const std::string& input,
+                   std::vector<MappedMemoryRegion>* regions_out) {
+  std::vector<MappedMemoryRegion> regions;
+
+  // This isn't async safe nor terribly efficient, but it doesn't need to be at
+  // this point in time.
+
+  // Split the string by newlines.
+  std::vector<std::string> lines;
+  std::string line = "";
+  for (size_t i = 0; i < input.size(); i++) {
+    if (input[i] != '\n' && input[i] != '\r') {
+      line.push_back(input[i]);
+    } else if (line.size() > 0) {
+      lines.push_back(line);
+      line.clear();
+    }
+  }
+  if (line.size() > 0) {
+    BPLOG(ERROR) << "Input doesn't end in newline";
+    return false;
+  }
+
+  for (size_t i = 0; i < lines.size(); ++i) {
+    MappedMemoryRegion region;
+    const char* line = lines[i].c_str();
+    char permissions[5] = {'\0'};  // Ensure NUL-terminated string.
+    int path_index = 0;
+
+    // Sample format from man 5 proc:
+    //
+    // address           perms offset  dev   inode   pathname
+    // 08048000-08056000 r-xp 00000000 03:0c 64593   /usr/sbin/gpm
+    //
+    // The final %n term captures the offset in the input string, which is used
+    // to determine the path name. It *does not* increment the return value.
+    // Refer to man 3 sscanf for details.
+    if (sscanf(line, "%" SCNxPTR "-%" SCNxPTR " %4c %llx %hhx:%hhx %ld %n",
+               &region.start, &region.end, permissions, &region.offset,
+               &region.major_device, &region.minor_device, &region.inode,
+               &path_index) < 7) {
+      BPLOG(ERROR) << "sscanf failed for line: " << line;
+      return false;
+    }
+
+    region.permissions = 0;
+
+    if (permissions[0] == 'r')
+      region.permissions |= MappedMemoryRegion::READ;
+    else if (permissions[0] != '-')
+      return false;
+
+    if (permissions[1] == 'w')
+      region.permissions |= MappedMemoryRegion::WRITE;
+    else if (permissions[1] != '-')
+      return false;
+
+    if (permissions[2] == 'x')
+      region.permissions |= MappedMemoryRegion::EXECUTE;
+    else if (permissions[2] != '-')
+      return false;
+
+    if (permissions[3] == 'p')
+      region.permissions |= MappedMemoryRegion::PRIVATE;
+    else if (permissions[3] != 's' && permissions[3] != 'S')  // Shared memory.
+      return false;
+
+    // Pushing then assigning saves us a string copy.
+    regions.push_back(region);
+    regions.back().path.assign(line + path_index);
+  }
+
+  regions_out->swap(regions);
+  return true;
+}