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

src/processor/minidump.cc

Index: src/processor/minidump.cc
===================================================================
--- src/processor/minidump.cc	(revision 1474)
+++ src/processor/minidump.cc	(working copy)
@@ -55,6 +55,7 @@
 #include <iostream>
 #include <limits>
 #include <map>
+#include <sstream>
 #include <vector>
 
 #include "processor/range_map-inl.h"
@@ -71,6 +72,7 @@
 using std::istream;
 using std::ifstream;
 using std::numeric_limits;
+using std::stringstream;
 using std::vector;
 
 // Returns true iff |context_size| matches exactly one of the sizes of the
@@ -3972,8 +3974,274 @@
   }
 }
 
+//
+// MinidumpLinuxMaps
+//
 
+MinidumpLinuxMaps::MinidumpLinuxMaps(Minidump *minidump)
+    : MinidumpObject(minidump),
+      pathname_(),
+      raw_linux_maps_(NULL) {
+}
+
+MinidumpLinuxMaps::~MinidumpLinuxMaps() {
+  delete raw_linux_maps_;
+}
+
+bool MinidumpLinuxMaps::Read(vector<char> *data) {

[ivanpe, 2015/07/23 01:17:12]

There is already an implementation of this in Chromium code that you should
probably reuse:
 
https://code.google.com/p/chromium/codesearch#chromium/src/base/debug/proc_ma...

The Chromium version also has plenty of tests that you should reuse as well.

[liuandrew, 2015/07/23 16:14:50]

How do I reuse the Chromium code? Do I just copy the relevant files over into
this repository, or is there a specific way to import the code?

[liuandrew, 2015/07/24 23:25:36]

Done.

+  valid_ = false;
+
+  // Convert data vector into stringstream.
+  string str = "";
+  for (unsigned int i = 0; i < data->size(); i++) {
+    str.push_back((*data)[i]);
+  }
+  stringstream stream(str);
+  delete data;
+  data = NULL;
+
+  // Tokenize the string stream.
+  string address, perms, offset, dev, inode;
+  stream >> address >> perms >> offset >> dev >> inode >> pathname_;
+  // Check if the tokens are filled. The pathname is optional.
+  if (address.size() <= 0
+      || perms.size() <= 0
+      || offset.size() <= 0
+      || dev.size() <= 0
+      || inode.size() <= 0) {
+    BPLOG(ERROR) << "Malformed input string: not enough tokens";
+    return false;
+  }
+
+  // Load base address and region size.
+  size_t address_delimiter_index = address.find("-");
+  if (address_delimiter_index == string::npos) {
+    BPLOG(ERROR) << "Address delimiter not found";
+    return false;
+  }
+  uint64_t end_address = 0;
+  stringstream(address.substr(0, address_delimiter_index))
+      >> std::hex
+      >> base_address_;
+  stringstream(address.substr(address_delimiter_index + 1, address.size()))
+      >> std::hex
+      >> end_address;
+  if (base_address_ > end_address) {
+    BPLOG(ERROR) << "Base address greater than end address: "
+                 << base_address_
+                 << " > "
+                 << end_address;
+    return false;
+  }
+  region_size_ = end_address - base_address_;
+
+  // Load permissions.
+  if (perms.size() != 4) {
+    BPLOG(ERROR) << "Permission string incorrectly loaded";
+    return false;
+  }
+  if (perms[0] == 'r') {
+    is_readable_ = true;
+  } else if (perms[0] == '-') {
+    is_readable_ = false;
+  } else {
+    BPLOG(ERROR) << "Invalid permission character: " << perms[0];
+    return false;
+  }
+  if (perms[1] == 'w') {
+    is_writeable_ = true;
+  } else if (perms[1] == '-') {
+    is_writeable_ = false;
+  } else {
+    BPLOG(ERROR) << "Invalid permission character: " << perms[1];
+    return false;
+  }
+  if (perms[2] == 'x') {
+    is_executable_ = true;
+  } else if (perms[2] == '-') {
+    is_executable_ = false;
+  } else {
+    BPLOG(ERROR) << "Invalid permission character: " << perms[2];
+    return false;
+  }
+  if (perms[3] == 's') {
+    is_shared_ = true;
+  } else if (perms[3] == 'p') {
+    is_shared_ = false;
+  } else {
+    BPLOG(ERROR) << "Invalid permission character: " << perms[3];
+    return false;
+  }
+
+  // Load offset.
+  stringstream(offset) >> std::hex >> offset_;
+
+  // Load major and minor devices.
+  size_t device_delimiter_index = dev.find(":");
+  if (device_delimiter_index == string::npos) {
+    BPLOG(ERROR) << "Device delimiter not found";
+    return false;
+  }
+  uint64_t major_container, minor_container;
+  stringstream(dev.substr(0, device_delimiter_index))
+      >> std::hex
+      >> major_container;
+  stringstream(dev.substr(device_delimiter_index + 1, dev.size()))
+      >> std::hex
+      >> minor_container;
+  major_device_ = static_cast<uint8_t>(major_container);
+  minor_device_ = static_cast<uint8_t>(minor_container);
+
+  // Load inode.
+  stringstream(inode) >> inode_;
+
+  valid_ = true;
+  return true;
+}
+
+void MinidumpLinuxMaps::Print() {
+  if (!valid_) {
+    BPLOG(ERROR) << "MinidumpLinuxMaps cannot print invalid data";
+    return;
+  }
+  // Print the contents of raw_linux_maps_.
+  for (unsigned int i = 0; i < raw_linux_maps_->size(); i++) {
+    printf("%c", (*raw_linux_maps_)[i]);
+  }
+}
+
 //
+// MinidumpLinuxMapsList
+//
+
+MinidumpLinuxMapsList::MinidumpLinuxMapsList(Minidump *minidump)
+    : MinidumpStream(minidump),
+      maps_(NULL),
+      maps_count_(0),
+      raw_linux_maps_list_() {
+}
+
+MinidumpLinuxMapsList::~MinidumpLinuxMapsList() {
+  for (unsigned int i = 0; i < maps_->size(); i++) {
+    delete (*maps_)[i];
+  }
+  delete maps_;
+}
+
+const MinidumpLinuxMaps *MinidumpLinuxMapsList::GetLinuxMapsForAddress(
+    uint64_t address) const {
+  if (!valid_) {
+    BPLOG(ERROR) << "Invalid MinidumpLinuxMapsList for GetLinuxMapsForAddress";
+    return NULL;
+  }
+
+  // Search every memory mapping.
+  for (unsigned int index = 0; index < maps_count_; index++) {
+    // Check if address is within bounds of the current memory region.
+    if ((*maps_)[index]->GetBase() <= address &&
+        (*maps_)[index]->GetBase() + (*maps_)[index]->GetSize() > address) {
+      return (*maps_)[index];
+    }
+  }
+
+  // No mapping encloses the memory address.
+  BPLOG(ERROR) << "MinidumpLinuxMapsList has no mapping at "
+               << HexString(address);
+  return NULL;
+}
+
+const MinidumpLinuxMaps *MinidumpLinuxMapsList::GetLinuxMapsAtIndex(
+    unsigned int index) const {
+  if (!valid_) {
+    BPLOG(ERROR) << "Invalid MinidumpLinuxMapsList for GetLinuxMapsAtIndex";
+    return NULL;
+  }
+
+  // Index out of bounds.
+  if (index >= maps_count_) {
+    BPLOG(ERROR) << "MinidumpLinuxMapsList index of out range: "
+                 << index
+                 << "/"
+                 << maps_count_;
+    return NULL;
+  }
+  return (*maps_)[index];
+}
+
+bool MinidumpLinuxMapsList::Read(uint32_t expected_size) {
+  // Invalidate cached data.
+  delete maps_;
+  maps_ = NULL;
+  maps_count_ = 0;
+  raw_linux_maps_list_.clear();
+
+  valid_ = false;
+
+  // Load and check expected stream length.
+  uint32_t length = 0;
+  if (!minidump_->SeekToStreamType(MD_LINUX_MAPS, &length)) {
+    BPLOG(ERROR) << "MinidumpLinuxMapsList stream type not found";
+    return false;
+  }
+  if (expected_size != length) {
+    BPLOG(ERROR) << "MinidumpLinuxMapsList size mismatch: "
+                 << expected_size
+                 << " != "
+                 << length;
+    return false;
+  }
+
+  // Read data from stream into raw_linux_maps_list_.
+  raw_linux_maps_list_.resize(length);
+  if (!minidump_->ReadBytes(&raw_linux_maps_list_[0], length)) {
+    BPLOG(ERROR) << "MinidumpLinuxMapsList failed to read bytes";
+    return false;
+  }
+  scoped_ptr<vector<char> > map_data(new vector<char>());
+  scoped_ptr<MinidumpLinuxMaps> map_entry(new MinidumpLinuxMaps(minidump_));
+  scoped_ptr<MinidumpLinuxMappings> maps(new MinidumpLinuxMappings());
+
+  // Load all of the raw list into a list of MinidumpLinuxMaps.
+  for (unsigned int i = 0; i < raw_linux_maps_list_.size(); i++) {
+    // Push character into data buffer.
+    map_data->push_back(raw_linux_maps_list_[i]);
+
+    // A newline marks the end of a mapping entry.
+    if (raw_linux_maps_list_[i] == '\n') {
+      // Read entry data into MinidumpLinuxMaps object.
+      if (!map_entry->Read(map_data.release())) {
+        BPLOG(ERROR) << "MinidumpLinuxMapsList failed to read entry";
+        return false;
+      }
+      // Add completed map entry into vector.
+      maps->push_back(map_entry.release());
+
+      // Reset scoped pointers.
+      map_data.reset(new vector<char>());
+      map_entry.reset(new MinidumpLinuxMaps(minidump_));
+    }
+  }
+
+  // Set instance variables.
+  maps_ = maps.release();
+  maps_count_ = maps_->size();
+  valid_ = true;
+  return true;
+}
+
+void MinidumpLinuxMapsList::Print() {
+  if (!valid_) {
+    BPLOG(ERROR) << "MinidumpLinuxMapsList cannot print valid data";
+    return;
+  }
+
+  // Print contents of raw_linux_maps_list_.
+  for (unsigned int i = 0; i < raw_linux_maps_list_.size(); i++) {
+    printf("%c", raw_linux_maps_list_[i]);
+  }
+}
+
+//
 // Minidump
 //
 
@@ -4292,6 +4560,11 @@
   return GetStream(&memory_info_list);
 }
 
+MinidumpLinuxMapsList *Minidump::GetLinuxMapsList() {
+  MinidumpLinuxMapsList *linux_maps_list;
+  return GetStream(&linux_maps_list);
+}
+
 static const char* get_stream_name(uint32_t stream_type) {
   switch (stream_type) {
   case MD_UNUSED_STREAM: