/* Copyright (c) 2006, Google Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* ---
* Author: Maxim Lifantsev
*/
#ifndef BASE_MEMORY_REGION_MAP_H_
#define BASE_MEMORY_REGION_MAP_H_
#include <config.h>
#ifdef HAVE_PTHREAD
#include <pthread.h>
#endif
#include <stddef.h>
#include <set>
#include "base/stl_allocator.h"
#include "base/spinlock.h"
#include "base/thread_annotations.h"
#include "base/low_level_alloc.h"
// TODO(maxim): add a unittest:
// execute a bunch of mmaps and compare memory map what strace logs
// execute a bunch of mmap/munmup and compare memory map with
// own accounting of what those mmaps generated
// Thread-safe class to collect and query the map of all memory regions
// in a process that have been created with mmap, munmap, mremap, sbrk.
// For each memory region, we keep track of (and provide to users)
// the stack trace that allocated that memory region.
// The recorded stack trace depth is bounded by
// a user-supplied max_stack_depth parameter of Init().
// After initialization with Init()
// (which can happened even before global object constructor execution)
// we collect the map by installing and monitoring MallocHook-s
// to mmap, munmap, mremap, sbrk.
// At any time one can query this map via provided interface.
// For more details on the design of MemoryRegionMap
// see the comment at the top of our .cc file.
class MemoryRegionMap {
private:
// Max call stack recording depth supported by Init(). Set it to be
// high enough for all our clients. Note: we do not define storage
// for this (doing that requires special handling in windows), so
// don't take the address of it!
static const int kMaxStackDepth = 32;
public:
// interface ================================================================
// Every client of MemoryRegionMap must call Init() before first use,
// and Shutdown() after last use. This allows us to reference count
// this (singleton) class properly. MemoryRegionMap assumes it's the
// only client of MallocHooks, so a client can only register other
// MallocHooks after calling Init() and must unregister them before
// calling Shutdown().
// Initialize this module to record memory allocation stack traces.
// Stack traces that have more than "max_stack_depth" frames
// are automatically shrunk to "max_stack_depth" when they are recorded.
// Init() can be called more than once w/o harm, largest max_stack_depth
// will be the effective one.
// It will install mmap, munmap, mremap, sbrk hooks
// and initialize arena_ and our hook and locks, hence one can use
// MemoryRegionMap::Lock()/Unlock() to manage the locks.
// Uses Lock/Unlock inside.
static void Init(int max_stack_depth);
// Try to shutdown this module undoing what Init() did.
// Returns true iff could do full shutdown (or it was not attempted).
// Full shutdown is attempted when the number of Shutdown() calls equals
// the number of Init() calls.
static bool Shutdown();
// Locks to protect our internal data structures.
// These also protect use of arena_ if our Init() has been done.
// The lock is recursive.
static void Lock() EXCLUSIVE_LOCK_FUNCTION(lock_);
static void Unlock() UNLOCK_FUNCTION(lock_);
// Returns true when the lock is held by this thread (for use in RAW_CHECK-s).
static bool LockIsHeld();
// Locker object that acquires the MemoryRegionMap::Lock
// for the duration of its lifetime (a C++ scope).
class LockHolder {
public:
LockHolder() { Lock(); }
~LockHolder() { Unlock(); }
private:
DISALLOW_COPY_AND_ASSIGN(LockHolder);
};
// A memory region that we know about through malloc_hook-s.
// This is essentially an interface through which MemoryRegionMap
// exports the collected data to its clients. Thread-compatible.
struct Region {
uintptr_t start_addr; // region start address
uintptr_t end_addr; // region end address
int call_stack_depth; // number of caller stack frames that we saved
const void* call_stack[kMaxStackDepth]; // caller address stack array
// filled to call_stack_depth size
bool is_stack; // does this region contain a thread's stack:
// a user of MemoryRegionMap supplies this info
// Convenience accessor for call_stack[0],
// i.e. (the program counter of) the immediate caller
// of this region's allocation function,
// but it also returns NULL when call_stack_depth is 0,
// i.e whe we weren't able to get the call stack.
// This usually happens in recursive calls, when the stack-unwinder
// calls mmap() which in turn calls the stack-unwinder.
uintptr_t caller() const {
return reinterpret_cast<uintptr_t>(call_stack_depth >= 1
? call_stack[0] : NULL);
}
// Return true iff this region overlaps region x.
bool Overlaps(const Region& x) const {
return start_addr < x.end_addr && end_addr > x.start_addr;
}
private: // helpers for MemoryRegionMap
friend class MemoryRegionMap;
// The ways we create Region-s:
void Create(const void* start, size_t size) {
start_addr = reinterpret_cast<uintptr_t>(start);
end_addr = start_addr + size;
is_stack = false; // not a stack till marked such
call_stack_depth = 0;
AssertIsConsistent();
}
void set_call_stack_depth(int depth) {
RAW_DCHECK(call_stack_depth == 0, ""); // only one such set is allowed
call_stack_depth = depth;
AssertIsConsistent();
}
// The ways we modify Region-s:
void set_is_stack() { is_stack = true; }
void set_start_addr(uintptr_t addr) {
start_addr = addr;
AssertIsConsistent();
}
void set_end_addr(uintptr_t addr) {
end_addr = addr;
AssertIsConsistent();
}
// Verifies that *this contains consistent data, crashes if not the case.
void AssertIsConsistent() const {
RAW_DCHECK(start_addr < end_addr, "");
RAW_DCHECK(call_stack_depth >= 0 &&
call_stack_depth <= kMaxStackDepth, "");
}
// Post-default construction helper to make a Region suitable
// for searching in RegionSet regions_.
void SetRegionSetKey(uintptr_t addr) {
// make sure *this has no usable data:
if (DEBUG_MODE) memset(this, 0xFF, sizeof(*this));
end_addr = addr;
}
// Note: call_stack[kMaxStackDepth] as a member lets us make Region
// a simp
