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/*
* Copyright (C) 2010 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 <ctype.h>
#include <dirent.h>
#include <errno.h>
#include <error.h>
#include <libgen.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/statfs.h>
#include <unistd.h>
#include <algorithm>
#include <limits>
#include <memory>
#include <set>
#include <string>
#include <android-base/file.h>
#include <android-base/parseint.h>
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
#include "applypatch/applypatch.h"
#include "otautil/cache_location.h"
static int EliminateOpenFiles(const std::string& dirname, std::set<std::string>* files) {
std::unique_ptr<DIR, decltype(&closedir)> d(opendir("/proc"), closedir);
if (!d) {
printf("error opening /proc: %s\n", strerror(errno));
return -1;
}
struct dirent* de;
while ((de = readdir(d.get())) != 0) {
unsigned int pid;
if (!android::base::ParseUint(de->d_name, &pid)) {
continue;
}
std::string path = android::base::StringPrintf("/proc/%s/fd/", de->d_name);
struct dirent* fdde;
std::unique_ptr<DIR, decltype(&closedir)> fdd(opendir(path.c_str()), closedir);
if (!fdd) {
printf("error opening %s: %s\n", path.c_str(), strerror(errno));
continue;
}
while ((fdde = readdir(fdd.get())) != 0) {
std::string fd_path = path + fdde->d_name;
char link[FILENAME_MAX];
int count = readlink(fd_path.c_str(), link, sizeof(link)-1);
if (count >= 0) {
link[count] = '\0';
if (android::base::StartsWith(link, dirname)) {
if (files->erase(link) > 0) {
printf("%s is open by %s\n", link, de->d_name);
}
}
}
}
}
return 0;
}
static std::vector<std::string> FindExpendableFiles(
const std::string& dirname, const std::function<bool(const std::string&)>& name_filter) {
std::set<std::string> files;
std::unique_ptr<DIR, decltype(&closedir)> d(opendir(dirname.c_str()), closedir);
if (!d) {
printf("error opening %s: %s\n", dirname.c_str(), strerror(errno));
return {};
}
// Look for regular files in the directory (not in any subdirectories).
struct dirent* de;
while ((de = readdir(d.get())) != 0) {
std::string path = dirname + "/" + de->d_name;
// We can't delete cache_temp_source; if it's there we might have restarted during
// installation and could be depending on it to be there.
if (path == CacheLocation::location().cache_temp_source()) {
continue;
}
// Do not delete the file if it doesn't have the expected format.
if (name_filter != nullptr && !name_filter(de->d_name)) {
continue;
}
struct stat st;
if (stat(path.c_str(), &st) == 0 && S_ISREG(st.st_mode)) {
files.insert(path);
}
}
printf("%zu regular files in deletable directory\n", files.size());
if (EliminateOpenFiles(dirname, &files) < 0) {
return {};
}
return std::vector<std::string>(files.begin(), files.end());
}
// Parses the index of given log file, e.g. 3 for last_log.3; returns max number if the log name
// doesn't have the expected format so that we'll delete these ones first.
static unsigned int GetLogIndex(const std::string& log_name) {
if (log_name == "last_log" || log_name == "last_kmsg") {
return 0;
}
unsigned int index;
if (sscanf(log_name.c_str(), "last_log.%u", &index) == 1 ||
sscanf(log_name.c_str(), "last_kmsg.%u", &index) == 1) {
return index;
}
return std::numeric_limits<unsigned int>::max();
}
int MakeFreeSpaceOnCache(size_t bytes_needed) {
#ifndef __ANDROID__
// TODO (xunchang) implement a heuristic cache size check during host simulation.
printf("Skip making (%zu) bytes free space on /cache; program is running on host\n",
bytes_needed);
return 0;
#endif
std::vector<std::string> dirs = { "/cache", CacheLocation::location().cache_log_directory() };
for (const auto& dirname : dirs) {
if (RemoveFilesInDirectory(bytes_needed, dirname, FreeSpaceForFile)) {
return 0;
}
}
return -1;
}
bool RemoveFilesInDirectory(size_t bytes_needed, const std::string& dirname,
const std::function<size_t(const std::string&)>& space_checker) {
struct stat st;
if (stat(dirname.c_str(), &st) != 0) {
error(0, errno, "Unable to free space on %s", dirname.c_str());
return false;
}
if (!S_ISDIR(st.st_mode)) {
printf("%s is not a directory\n", dirname.c_str());
return false;
}
size_t free_now = space_checker(dirname);
printf("%zu bytes free on %s (%zu needed)\n", free_now, dirname.c_str(), bytes_needed);
if (free_now >= bytes_needed) {
return true;
}
std::vector<std::string> files;
if (dirname == CacheLocation::location().cache_log_directory()) {
// Deletes the log files only.
auto log_filter = [](const std::string& file_name) {
return android::base::StartsWith(file_name, "last_log") ||
android::base::StartsWith(file_name, "last_kmsg");
};
files = FindExpendableFiles(dirname, log_filter);
// Older logs will come to the top of the queue.
auto comparator = [](const std::string& name1, const std::string& name2) -> bool {
unsigned int index1 = GetLogIndex(android::base::Basename(name1));
unsigned int index2 = GetLogIndex(android::base::Basename(name2));
if (index1 == index2) {
return name1 < name2;
}
return index1 > index2;
};
std::sort(files.begin(), files.end(), comparator);
} else {
// We're allowed to delete unopened regular files in the directory.
files = FindExpendableFiles(dirname, nullptr);
}
for (const auto& file : files) {
if (unlink(file.c_str()) == -1) {
error(0, errno, "Failed to delete %s", file.c_str());
continue;
}
free_now = space_checker(dirname);
printf("deleted %s; now %zu bytes free\n", file.c_str(), free_now);
if (free_now >= bytes_needed) {
return true;
}
}
return false;
}
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