// Copyright 2013 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <fcntl.h>
#include <signal.h>
#include <stddef.h>
#include <stdint.h>
#include <sys/types.h>
#include <unistd.h>
#include <algorithm>
#include <cstring>
#include <fstream>
#include <iostream>
#include <limits>
#include <string>
#include <string_view>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>
#include "base/base64.h"
#include "base/files/file_util.h"
#include "base/files/scoped_file.h"
#include "base/format_macros.h"
#include "base/logging.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_split.h"
#include "base/strings/stringprintf.h"
#include "third_party/abseil-cpp/absl/cleanup/cleanup.h"
const unsigned int kPageSize = getpagesize();
namespace {
class BitSet {
public:
void resize(size_t nbits) {
data_.resize((nbits + 7) / 8);
}
void set(uint32_t bit) {
const uint32_t byte_idx = bit / 8;
CHECK(byte_idx < data_.size());
data_[byte_idx] |= (1 << (bit & 7));
}
std::string AsB64String() const {
// Simple optimization: strip trailing zero bytes from the bitmap.
// For instance, if a region has 32 pages but only the first 9 are resident,
// The full bitmap would be 0xff 0x01 0x00 0x00, the stripped one 0xff 0x01.
// It can save up to some seconds when printing large mmaps, in particular
// in presence of large virtual address space reservations (where none of
// the pages are resident).
size_t end = data_.size();
while (end > 0 && data_[end - 1] == '\0')
--end;
return base::Base64Encode(std::string_view(data_.data(), end));
}
private:
std::vector<char> data_;
};
// An entry in /proc/<pid>/pagemap.
struct PageMapEntry {
uint64_t page_frame_number : 55;
uint unused : 8;
uint present : 1;
};
// Describes a memory page.
struct PageInfo {
int64_t page_frame_number; // Physical page id, also known as PFN.
int64_t flags;
int32_t times_mapped;
};
struct PageCount {
PageCount() : total_count(0), unevictable_count(0) {}
int total_count;
int unevictable_count;
};
struct MemoryMap {
std::string name;
std::string flags;
uint64_t start_address;
uint64_t end_address;
uint64_t offset;
PageCount private_pages;
// app_shared_pages[i] contains the number of pages mapped in i+2 processes
// (only among the processes that are being analyzed).
std::vector<PageCount> app_shared_pages;
PageCount other_shared_pages;
std::vector<PageInfo> committed_pages;
// committed_pages_bits is a bitset reflecting the present bit for all the
// virtual pages of the mapping.
BitSet committed_pages_bits;
};
struct ProcessMemory {
pid_t pid;
std::vector<MemoryMap> memory_maps;
};
bool PageIsUnevictable(const PageInfo& page_info) {
// These constants are taken from kernel-page-flags.h.
const int KPF_DIRTY = 4; // Note that only file-mapped pages can be DIRTY.
const int KPF_ANON = 12; // Anonymous pages are dirty per definition.
const int KPF_UNEVICTABLE = 18;
const int KPF_MLOCKED = 33;
return (page_info.flags & ((1ll << KPF_DIRTY) |
(1ll << KPF_ANON) |
(1ll << KPF_UNEVICTABLE) |
(1ll << KPF_MLOCKED))) ?
true : false;
}
// Number of times a physical page is mapped in a process.
typedef std::unordered_map<uint64_t, int> PFNMap;
// Parses lines from /proc/<PID>/maps, e.g.:
// 401e7000-401f5000 r-xp 00000000 103:02 158 /system/bin/linker
bool ParseMemoryMapLine(const std::string& line,
std::vector<std::string>* tokens,
MemoryMap* memory_map) {
*tokens = base::SplitString(
line, " ", base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL);
if (tokens->size() < 2)
return false;
const std::string& addr_range = tokens->at(0);
std::vector<std::string> range_tokens = base::SplitString(
addr_range, "-", base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL);
const std::string& start_address_token = range_tokens.at(0);
if (!base::HexStringToUInt64(start_address_token,
&memory_map->start_address)) {
return false;
}
const std::string& end_address_token = range_tokens.at(1);
if (!base::HexStringToUInt64(end_address_token, &memory_map->end_address)) {
return false;
}
if (tokens->at(1).size() != strlen("rwxp"))
return false;
memory_map->flags.swap(tokens->at(1));
if (!base::HexStringToUInt64(tokens->at(2), &memory_map->offset))
return false;
memory_map->committed_pages_bits.resize(
(memory_map->end_address - memory_map->start_address) / kPageSize);
const int map_name_index = 5;
if (tokens->size() >= map_name_index + 1) {
for (std::vector<std::string>::const_iterator it =
tokens->begin() + map_name_index; it != tokens->end(); ++it) {
if (!it->empty()) {
if (!memory_map->name.empty())
memory_map->name.append(" ");
memory_map->name.append(*it);
}
}
}
return true;
}
// Reads sizeof(T) bytes from file |fd| at |offset|.
template <typename T>
bool ReadFromFileAtOffset(int fd, off_t offset, T* value) {
if (lseek64(fd, offset * sizeof(*value), SEEK_SET) < 0) {
PLOG(ERROR) << "lseek";
return false;
}
ssize_t bytes = read(fd, value, sizeof(*value));
if (bytes != sizeof(*value) && bytes != 0) {
PLOG(ERROR) << "read";
return false;
}
return true;
}
// Fills |process_maps| in with the process memory maps identified by |pid|.
bool GetProcessMaps(pid_t pid, std::vector<MemoryMap>* process_maps) {
std::ifstream maps_file(base::StringPrintf("/proc/%d/maps", pid).c_str());
if (!maps_file.good()) {
PLOG(ERROR) << "open";
return false;
}
std::string line;
std::vector<std::string> tokens;
while (std::getline(maps_file, line) && !line.empty()) {
MemoryMap memory_map = {};
if (!ParseMemoryMapLine(line, &tokens, &memory_map)) {
LOG(ERROR) << "Could not parse line: " << line;
return false;
}
process_maps->push_back(memory_map);
}
return true;
}
// Fills |committed_pages| in with the set of committed pages contained in the
// provided memory map.
bool GetPagesForMemoryMap(int pagemap_fd,
const MemoryMap& memory_map,
std::vector<PageInfo>* committed_pages,
BitSet* committed_pages_bits) {
const off64_t offset = memory_map.start_address / kPageSize;
if (lseek64(pagemap_fd, offset * sizeof(PageMapEntry), SEEK_SET) < 0) {
PLOG(ERROR) << "lseek";
return false;
}
for (uint64_t addr = memory_map.start_address, page_index = 0;
addr < memory_map.end_address; addr += kPageSize, ++page_index) {
DCHECK_EQ(0u, addr % kPageSize);
PageMapEntry page_map_entry = {};
static_assert(sizeof(PageMapEntry) == sizeof(uint64_t), "unexpected size");
ssize_t bytes = read(pagemap_fd, &page_map_entry, sizeof(page_map_entry));
if (bytes != sizeof(PageMapEntry) && bytes != 0) {
PLOG(ERROR) << "read";
return false;
}
if (page_map_entry.present) { // Ignore non-committed pages.
if (page_map_entry.page_frame_number == 0)
continue;
PageInfo page_info = {};
page_info.page_frame_number = page_map_entry.page_frame_number;
committed_pages->push_back(page_info);
committed_pages_bits->set(page_index);
}
}
return true;
}
// Fills |committed_pages| with mapping count and flags information gathered
// looking-up /proc/kpagecount and /proc/kpageflags.
bool SetPagesInfo(int pagecount_fd,
int pageflags_fd,
std::vector<PageInfo>* pages) {
for (std::vector<PageInfo>::iterator it = pages->begin();
it != pages->end(); ++it) {
PageInfo* const page_info = &*it;
int64_t times_mapped;
if (!ReadFromFileAtOffset(
pagecount_fd, page_info->page_frame_number, ×_mapped)) {
return false;
}
DCHECK(times_mapped <= std::numeric_limits<int32_t>::max());
page_info->times_mapped = static_cast<int32_t>(times_mapped);
int64_t page_flags;
if (!ReadFromFileAtOffset(
pageflags_fd, page_info->page_frame_number, &page_flags)) {
return false;
}
page_info->flags = page_flags;
}
return true;
}
// Fills in the provided vector of Page Frame Number maps. This lets
// ClassifyPages() know how many times each page is mapped in the processes.
void FillPFNMaps(const std::vector<ProcessMemory>& processes_memory,
std::vector<PFNMap>* pfn_maps) {
int current_process_index = 0;
for (std::vector<ProcessMemory>::const_iterator memory_it =
processes_memory.begin();
memory_it != processes_memory.end();
++memory_it, ++current_process_index) {
const std::vector<MemoryMap>& memory_maps = memory_it->memory_maps;
for (std::vector<MemoryMap>::const_iterator map_it = memory_maps.begin();
map_it != memory_maps.end(); ++map_it) {
const std::vector<PageInfo>& pages = map_it->committed_pages;
for (std::vector<PageInfo>::const_iterator page_it = pages.begin();
page_it != pages.end(); ++page_it) {
const PageInfo& page_info = *page_it;
PFNMap* const pfn_map = &(*pfn_maps)[current_process_index];
const std::pair<PFNMap::iterator, bool> result = pfn_map->insert(
std::make_pair(page_info.page_frame_number, 0));
++result.first->second;
}
}
}
}
// Sets the private_count/app_shared_pages/other_shared_count fields of the
// provided memory maps for each process.
void ClassifyPages(std::vector<ProcessMemory>* processes_memory) {
std::vector<PFNMap> pfn_maps(processes_memory->size());
FillPFNMaps(*processes_memory, &pfn_maps);
// Hash set keeping track of the physical pages mapped in a single process so
// that they can be counted only once.
std::unordered_set<uint64_t> physical_pages_mapped_in_process;
for (std::vector<ProcessMemory>::iterator memory_it =
processes_memory->begin();
memory_it != processes_memory->end(); ++memory_it) {
std::vector<MemoryMap>* const memory_maps = &memory_it->memory_maps;
physical_pages_mapped_in_process.clear();
for (std::vector<MemoryMap>::iterator map_it = memory_maps->begin();
map_it != memory_maps->end(); ++map_it) {
MemoryMap* const memory_map = &*map_it;
const size_t processes_count = processes_memory->size();
memory_map->app_shared_pages.resize(processes_count - 1);
const std::vector<PageInfo>& pages = memory_map->committed_pages;
for (std::vector<PageInfo>::const_iterator page_it = pages.begin();
page_it != pages.end(); ++page_it) {
const PageInfo& page_info = *page_it;
if (page_info.times_mapped == 1) {
++memory_map->private_pages.total_count;
if (PageIsUnevictable(page_info))
++memory_map->private_pages.unevictable_count;
continue;
}
const uint64_t page_frame_number = page_info.page_frame_number;
const std::pair<std::unordered_set<uint64_t>::iterator, bool> result =
physical_pages_mapped_in_process.insert(page_frame_number);
const bool did_insert = result.second;
if (!did_insert) {
// This physical page (mapped multiple times in the same process) was
// already counted.
continue;
}
// See if the current physical page is also mapped in the other
// processes that are being analyzed.
int times_mapped = 0;
int mapped_in_processes_count = 0;
for (std::vector<PFNMap>::const_iterator pfn_map_it = pfn_maps.begin();
pfn_map_it != pfn_maps.end(); ++pfn_map_it) {
const PFNMap& pfn_map = *pfn_map_it;
const PFNMap::const_iterator found_it = pfn_map.find(
page_frame_number);
if (found_it == pfn_map.end())
continue;
++mapped_in_processes_count;
times_mapped += found_it->second;
}
PageCount* page_count_to_update = NULL;
if (times_mapped == page_info.times_mapped) {
// The physical page is only mapped in the processes that are being
// analyzed.
if (mapped_in_processes_count > 1) {
// The physical page is mapped in multiple processes.
page_count_to_update =
&memory_map->app_shared_pages[mapped_in_processes_count - 2];
} else {
// The physical page is mapped multiple times in the same process.
page_count_to_update = &memory_map->private_pages;
}
} else {
page_count_to_update = &memory_map->other_shared_pages;
}
++page_count_to_update->total_count;
if (PageIsUnevictable(page_info))
++page_count_to_update->unevictable_count;
}
}
}
}
void AppendAppSharedField(const std::vector<PageCount>& app_shared_pages,
std::string* out) {
out->append("[");
for (std::vector<PageCount>::const_iterator it = app_shared_pages.begin();
it != app_shared_pages.end(); ++it) {
out->append(base::NumberToString(it->total_count * kPageSize));
out->append(":");
out->append(base::NumberToString(it->unevictable_count * kPageSize));
if (it + 1 != app_shared_pages.end())
out->append(",");
}
out->append("]");
}
void DumpProcessesMemoryMapsInShortFormat(
const std::vector<ProcessMemory>& processes_memory) {
const int KB_PER_PAGE = kPageSize >> 10;
std::vector<int> totals_app_shared(processes_memory.size());
std::cout << "pid\tprivate\t\tshared_app\tshared_other (KB)\n";
for (std::vector<ProcessMemory>::const_iterator memory_it =
processes_memory.begin();
memory_it != processes_memory.end(); ++memory_it) {
const ProcessMemory& process_memory = *memory_it;
std::fill(totals_app_shared.begin(), totals_app_shared.end(), 0);
int total_private = 0, total_other_shared = 0;
const std::vector<MemoryMap>& memory_maps = process_memory.memory_maps;
for (std::vector<MemoryMap>::const_iterator map_it = memory_maps.begin();
map_it != memory_maps.end(); ++map_it) {
const MemoryMap& memory_map = *map_it;
total_private += memory_map.private_pages.total_count;
for (size_t i = 0; i < memory_map.app_shared_pages.size(); ++i)
totals_app_shared[i] += memory_map.app_shared_pages[i].total_count;
total_other_shared += memory_map.other_shared_pages.total_count;
}
double total_app_shared = 0;
for (size_t i = 0; i < totals_app_shared.size(); ++i)
total_app_shared += static_cast<double>(totals_app_shared[i]) / (i + 2);
std::cout << base::StringPrintf(
"%d\t%d\t\t%d\t\t%d\n", process_memory.pid, total_private * KB_PER_PAGE,
static_cast<int>(total_app_shared) * KB_PER_PAGE,
total_other_shared * KB_PER_PAGE);
}
}
void DumpProcessesMemoryMapsInExtendedFormat(
const std::vector<ProcessMemory>& processes_memory) {
std::string app_shared_buf;
for (std::vector<ProcessMemory>::const_iterator memory_it =
processes_memory.begin();
memory_it != processes_memory.end(); ++memory_it) {
const ProcessMemory& process_memory = *memory_it;
std::cout << "[ PID=" << process_memory.pid << "]" << '\n';
const std::vector<MemoryMap>& memory_maps = process_memory.memory_maps;
for (std::vector<MemoryMap>::const_iterator map_it = memory_maps.begin();
map_it != memory_maps.end(); ++map_it) {
const MemoryMap& memory_map = *map_it;
app_shared_buf.clear();
AppendAppSharedField(memory_map.app_shared_pages, &app_shared_buf);
std::cout << base::StringPrintf(
"%" PRIx64 "-%" PRIx64 " %s %" PRIx64
" private_unevictable=%d "
"private=%d shared_app=%s shared_other_unevictable=%d "
"shared_other=%d \"%s\" [%s]\n",
memory_map.start_address, memory_map.end_address,
memory_map.flags.c_str(), memory_map.offset,
memory_map.private_pages.unevictable_count * kPageSize,
memory_map.private_pages.total_count * kPageSize,
app_shared_buf.c_str(),
memory_map.other_shared_pages.unevictable_count * kPageSize,
memory_map.other_shared_pages.total_count * kPageSize,
memory_map.name.c_str(),
memory_map.committed_pages_bits.AsB64String().c_str());
}
}
}
bool CollectProcessMemoryInformation(int page_count_fd,
int page_flags_fd,
ProcessMemory* process_memory) {
const pid_t pid = process_memory->pid;
base::ScopedFD pagemap_fd(HANDLE_EINTR(open(
base::StringPrintf("/proc/%d/pagemap", pid).c_str(), O_RDONLY)));
if (!pagemap_fd.is_valid()) {
PLOG(ERROR) << "open";
return false;
}
std::vector<MemoryMap>* const process_maps = &process_memory->memory_maps;
if (!GetProcessMaps(pid, process_maps))
return false;
for (std::vector<MemoryMap>::iterator it = process_maps->begin();
it != process_maps->end(); ++it) {
std::vector<PageInfo>* const committed_pages = &it->committed_pages;
BitSet* const pages_bits = &it->committed_pages_bits;
GetPagesForMemoryMap(pagemap_fd.get(), *it, committed_pages, pages_bits);
SetPagesInfo(page_count_fd, page_flags_fd, committed_pages);
}
return true;
}
void KillAll(const std::vector<pid_t>& pids, int signal_number) {
for (std::vector<pid_t>::const_iterator it = pids.begin(); it != pids.end();
++it) {
kill(*it, signal_number);
}
}
void ExitWithUsage() {
LOG(ERROR) << "Usage: memdump [-a] <PID1>... <PIDN>";
exit(EXIT_FAILURE);
}
} // namespace
int main(int argc, char** argv) {
if (argc == 1)
ExitWithUsage();
const bool short_output = !strncmp(argv[1], "-a", 2);
if (short_output) {
if (argc == 2)
ExitWithUsage();
++argv;
}
std::vector<pid_t> pids;
for (const char* const* ptr = argv + 1; *ptr; ++ptr) {
pid_t pid;
if (!base::StringToInt(*ptr, &pid))
return EXIT_FAILURE;
pids.push_back(pid);
}
std::vector<ProcessMemory> processes_memory(pids.size());
{
base::ScopedFD page_count_fd(
HANDLE_EINTR(open("/proc/kpagecount", O_RDONLY)));
if (!page_count_fd.is_valid()) {
PLOG(ERROR) << "open /proc/kpagecount";
return EXIT_FAILURE;
}
base::ScopedFD page_flags_fd(open("/proc/kpageflags", O_RDONLY));
if (!page_flags_fd.is_valid()) {
PLOG(ERROR) << "open /proc/kpageflags";
return EXIT_FAILURE;
}
absl::Cleanup auto_resume_processes = [&pids] { KillAll(pids, SIGCONT); };
KillAll(pids, SIGSTOP);
for (std::vector<pid_t>::const_iterator it = pids.begin(); it != pids.end();
++it) {
ProcessMemory* const process_memory =
&processes_memory[it - pids.begin()];
process_memory->pid = *it;
if (!CollectProcessMemoryInformation(
page_count_fd.get(), page_flags_fd.get(), process_memory)) {
return EXIT_FAILURE;
}
}
}
ClassifyPages(&processes_memory);
if (short_output)
DumpProcessesMemoryMapsInShortFormat(processes_memory);
else
DumpProcessesMemoryMapsInExtendedFormat(processes_memory);
return EXIT_SUCCESS;
}
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