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/*
* Copyright (C) 2023 The Android Open Source Project
*
* 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
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "page_util.h"
#include "android-base/stringprintf.h"
namespace art {
using android::base::StringPrintf;
bool GetPageFlagsOrCount(art::File& kpage_file,
uint64_t page_frame_number,
/*out*/ uint64_t& page_flags_or_count,
/*out*/ std::string& error_msg) {
return GetPageFlagsOrCounts(kpage_file,
ArrayRef<const uint64_t>(&page_frame_number, 1u),
ArrayRef<uint64_t>(&page_flags_or_count, 1u),
error_msg);
}
bool GetPageFlagsOrCounts(File& kpage_file,
ArrayRef<const uint64_t> page_frame_numbers,
/*out*/ ArrayRef<uint64_t> page_flags_or_counts,
/*out*/ std::string& error_msg) {
static_assert(kPageFlagsEntrySize == kPageCountEntrySize, "entry size check");
CHECK_NE(page_frame_numbers.size(), 0u);
CHECK_EQ(page_flags_or_counts.size(), page_frame_numbers.size());
CHECK(page_frame_numbers.data() != nullptr);
CHECK(page_flags_or_counts.data() != nullptr);
size_t size = page_frame_numbers.size();
size_t i = 0;
while (i != size) {
size_t start = i;
++i;
while (i != size && page_frame_numbers[i] - page_frame_numbers[start] == i - start) {
++i;
}
// Read 64-bit entries from /proc/kpageflags or /proc/kpagecount.
if (!kpage_file.PreadFully(page_flags_or_counts.data() + start,
(i - start) * kPageMapEntrySize,
page_frame_numbers[start] * kPageFlagsEntrySize)) {
error_msg = StringPrintf("Failed to read the page flags or counts from %s, error: %s",
kpage_file.GetPath().c_str(),
strerror(errno));
return false;
}
}
return true;
}
bool GetPageFrameNumber(File& page_map_file,
size_t virtual_page_index,
/*out*/ uint64_t& page_frame_number,
/*out*/ std::string& error_msg) {
return GetPageFrameNumbers(
page_map_file, virtual_page_index, ArrayRef<uint64_t>(&page_frame_number, 1u), error_msg);
}
bool GetPageFrameNumbers(File& page_map_file,
size_t virtual_page_index,
/*out*/ ArrayRef<uint64_t> page_frame_numbers,
/*out*/ std::string& error_msg) {
CHECK_NE(page_frame_numbers.size(), 0u);
CHECK(page_frame_numbers.data() != nullptr);
// Read 64-bit entries from /proc/$pid/pagemap to get the physical page frame numbers.
if (!page_map_file.PreadFully(page_frame_numbers.data(),
page_frame_numbers.size() * kPageMapEntrySize,
virtual_page_index * kPageMapEntrySize)) {
error_msg = StringPrintf("Failed to read virtual page index entries from %s, error: %s",
page_map_file.GetPath().c_str(),
strerror(errno));
return false;
}
// Extract page frame numbers from pagemap entries.
for (uint64_t& page_frame_number : page_frame_numbers) {
page_frame_number &= kPageFrameNumberMask;
}
return true;
}
bool OpenFile(const char* file_name, /*out*/ File& file, /*out*/ std::string& error_msg) {
std::unique_ptr<File> file_ptr = std::unique_ptr<File>{OS::OpenFileForReading(file_name)};
if (file_ptr == nullptr) {
error_msg = StringPrintf("Failed to open file: %s", file_name);
return false;
}
file = std::move(*file_ptr);
return true;
}
bool OpenProcFiles(pid_t pid, /*out*/ ProcFiles& files, /*out*/ std::string& error_msg) {
if (!OpenFile("/proc/kpageflags", files.kpageflags, error_msg)) {
return false;
}
if (!OpenFile("/proc/kpagecount", files.kpagecount, error_msg)) {
return false;
}
std::string mem_file_name =
StringPrintf("/proc/%ld/mem", static_cast<long>(pid)); // NOLINT [runtime/int]
if (!OpenFile(mem_file_name.c_str(), files.mem, error_msg)) {
return false;
}
std::string pagemap_file_name =
StringPrintf("/proc/%ld/pagemap", static_cast<long>(pid)); // NOLINT [runtime/int]
if (!OpenFile(pagemap_file_name.c_str(), files.pagemap, error_msg)) {
return false;
}
return true;
}
} // namespace art
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