/*
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* Copyright (C) 2016 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#define LOG_TAG "DEBUG"
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#include "libdebuggerd/open_files_list.h"
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#include <android/fdsan.h>
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#include <dirent.h>
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/types.h>
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#include <unistd.h>
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#include <string>
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#include <utility>
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#include <vector>
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#include <android-base/file.h>
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#include <log/log.h>
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#include <unwindstack/Memory.h>
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#include "libdebuggerd/utility.h"
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#include "private/bionic_fdsan.h"
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void populate_open_files_list(OpenFilesList* list, pid_t pid) {
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std::string fd_dir_name = "/proc/" + std::to_string(pid) + "/fd";
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std::unique_ptr<DIR, int (*)(DIR*)> dir(opendir(fd_dir_name.c_str()), closedir);
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if (dir == nullptr) {
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ALOGE("failed to open directory %s: %s", fd_dir_name.c_str(), strerror(errno));
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return;
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}
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struct dirent* de;
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while ((de = readdir(dir.get())) != nullptr) {
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if (*de->d_name == '.') {
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continue;
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}
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int fd = atoi(de->d_name);
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std::string path = fd_dir_name + "/" + std::string(de->d_name);
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std::string target;
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if (android::base::Readlink(path, &target)) {
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(*list)[fd].path = target;
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} else {
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(*list)[fd].path = "???";
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ALOGE("failed to readlink %s: %s", path.c_str(), strerror(errno));
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}
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}
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}
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void populate_fdsan_table(OpenFilesList* list, std::shared_ptr<unwindstack::Memory> memory,
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uint64_t fdsan_table_address) {
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constexpr size_t inline_fds = sizeof(FdTable::entries) / sizeof(*FdTable::entries);
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static_assert(inline_fds == 128);
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size_t entry_offset = offsetof(FdTable, entries);
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for (size_t i = 0; i < inline_fds; ++i) {
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uint64_t address = fdsan_table_address + entry_offset + sizeof(FdEntry) * i;
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FdEntry entry;
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if (!memory->Read(address, &entry, sizeof(entry))) {
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ALOGE("failed to read fdsan table entry %zu: %s", i, strerror(errno));
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return;
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}
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if (entry.close_tag) {
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(*list)[i].fdsan_owner = entry.close_tag.load();
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}
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}
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size_t overflow_offset = offsetof(FdTable, overflow);
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uintptr_t overflow = 0;
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if (!memory->Read(fdsan_table_address + overflow_offset, &overflow, sizeof(overflow))) {
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ALOGE("failed to read fdsan table overflow pointer: %s", strerror(errno));
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return;
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}
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if (!overflow) {
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return;
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}
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size_t overflow_length;
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if (!memory->Read(overflow, &overflow_length, sizeof(overflow_length))) {
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ALOGE("failed to read fdsan overflow table length: %s", strerror(errno));
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return;
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}
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if (overflow_length > 131072) {
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ALOGE("unreasonable large fdsan overflow table size %zu, bailing out", overflow_length);
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return;
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}
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for (size_t i = 0; i < overflow_length; ++i) {
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int fd = i + inline_fds;
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uint64_t address = overflow + offsetof(FdTableOverflow, entries) + i * sizeof(FdEntry);
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FdEntry entry;
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if (!memory->Read(address, &entry, sizeof(entry))) {
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ALOGE("failed to read fdsan overflow entry for fd %d: %s", fd, strerror(errno));
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return;
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}
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if (entry.close_tag) {
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(*list)[fd].fdsan_owner = entry.close_tag;
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}
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}
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return;
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}
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void dump_open_files_list(log_t* log, const OpenFilesList& files, const char* prefix) {
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for (auto& [fd, entry] : files) {
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const std::optional<std::string>& path = entry.path;
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const std::optional<uint64_t>& fdsan_owner = entry.fdsan_owner;
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if (path && fdsan_owner) {
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const char* type = android_fdsan_get_tag_type(*fdsan_owner);
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uint64_t value = android_fdsan_get_tag_value(*fdsan_owner);
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_LOG(log, logtype::OPEN_FILES, "%sfd %i: %s (owned by %s %#" PRIx64 ")\n", prefix, fd,
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path->c_str(), type, value);
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} else if (path && !fdsan_owner) {
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_LOG(log, logtype::OPEN_FILES, "%sfd %i: %s (unowned)\n", prefix, fd, path->c_str());
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} else if (!path && fdsan_owner) {
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_LOG(log, logtype::OPEN_FILES, "%sfd %i: <MISSING> (owned by %#" PRIx64 ")\n", prefix, fd,
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*fdsan_owner);
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} else {
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ALOGE("OpenFilesList contains an entry (fd %d) with no path or owner", fd);
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}
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}
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}
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