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// Copyright 2017 The Crashpad Authors. All rights reserved.
// 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
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// See the License for the specific language governing permissions and
// limitations under the License.
#include <sys/types.h>
#include <memory>
#include <string>
#include <vector>
#include "util/linux/address_types.h"
#include "util/linux/checked_linux_address_range.h"
#include "util/linux/ptrace_connection.h"
#include "util/misc/initialization_state_dcheck.h"
namespace crashpad {
//! \brief Accesses information about mapped memory in another process.
//! The target process must be stopped to guarantee correct mappings. If the
//! target process is not stopped, mappings may be invalid after the return from
//! Initialize(), and even mappings existing at the time Initialize() was called
//! may not be found.
class MemoryMap {
//! \brief Information about a mapped region of memory.
struct Mapping {
bool Equals(const Mapping& other) const;
std::string name;
CheckedLinuxAddressRange range;
off64_t offset;
dev_t device;
ino_t inode;
bool readable;
bool writable;
bool executable;
bool shareable;
//! \brief Initializes this object with information about the mapped memory
//! regions in the process connected via \a connection.
//! This method must be called successfully prior to calling any other method
//! in this class. This method may only be called once.
//! \param[in] connection A connection to the process create a map for.
//! \return `true` on success, `false` on failure with a message logged.
bool Initialize(PtraceConnection* connection);
//! \return The Mapping containing \a address or `nullptr` if no match is
//! found. The caller does not take ownership of this object. It is scoped
//! to the lifetime of the MemoryMap object that it was obtained from.
const Mapping* FindMapping(LinuxVMAddress address) const;
//! \return The Mapping with the lowest base address whose name is \a name or
//! `nullptr` if no match is found. The caller does not take ownership of
//! this object. It is scoped to the lifetime of the MemoryMap object that
//! it was obtained from.
const Mapping* FindMappingWithName(const std::string& name) const;
//! \brief An abstract base class for iterating over ordered sets of mappings
//! in a MemoryMap.
class Iterator {
virtual ~Iterator() = default;
//! \return the mapping pointed to by the iterator and advance the iterator
//! to the next mapping. If there are no more mappings, this method
//! returns `nullptr` on all subsequent invocations.
virtual const Mapping* Next() = 0;
//! \return the number of mappings remaining.
virtual unsigned int Count() = 0;
Iterator() = default;
//! \brief Find possible initial mappings of files mapped over several
//! segments.
//! Executables and libaries are typically loaded into several mappings with
//! varying permissions for different segments. Portions of an ELF file may
//! be mapped multiple times as part of loading the file, for example, when
//! initializing GNU_RELRO segments.
//! This method searches for mappings at or below \a mapping in memory that
//! are mapped from the same file as \a mapping from offset 0.
//! On Android, ELF modules may be loaded from within a zipfile, so this
//! method may return mappings whose offset is not 0.
//! This method is intended to help identify the possible base address for
//! loaded modules, but it is the caller's responsibility to determine which
//! returned mapping is correct.
//! If \a mapping does not refer to a valid mapping, an empty vector will be
//! returned and a message will be logged. If \a mapping is found but does not
//! map a file, \a mapping is returned in \a possible_starts.
//! \param[in] mapping A Mapping whose series to find the start of.
//! \return a reverse iterator over the possible mapping starts, starting from
//! the mapping with highest base address.
std::unique_ptr<Iterator> FindFilePossibleMmapStarts(
const Mapping& mapping) const;
//! \return A reverse iterator over all mappings in the MemoryMap from \a
//! mapping to the start of the MemoryMap.
std::unique_ptr<Iterator> ReverseIteratorFrom(const Mapping& mapping) const;
std::vector<Mapping> mappings_;
InitializationStateDcheck initialized_;
} // namespace crashpad