143 lines
4.2 KiB
C++
143 lines
4.2 KiB
C++
/*
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* Copyright (C) 2010 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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#include <errno.h>
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#include <libgen.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/stat.h>
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#include <sys/statfs.h>
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#include <unistd.h>
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#include <dirent.h>
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#include <ctype.h>
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#include <memory>
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#include <set>
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#include <string>
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#include <android-base/parseint.h>
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#include <android-base/stringprintf.h>
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#include "applypatch.h"
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static int EliminateOpenFiles(std::set<std::string>* files) {
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std::unique_ptr<DIR, decltype(&closedir)> d(opendir("/proc"), closedir);
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if (!d) {
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printf("error opening /proc: %s\n", strerror(errno));
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return -1;
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}
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struct dirent* de;
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while ((de = readdir(d.get())) != 0) {
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unsigned int pid;
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if (!android::base::ParseUint(de->d_name, &pid)) {
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continue;
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}
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std::string path = android::base::StringPrintf("/proc/%s/fd/", de->d_name);
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struct dirent* fdde;
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std::unique_ptr<DIR, decltype(&closedir)> fdd(opendir(path.c_str()), closedir);
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if (!fdd) {
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printf("error opening %s: %s\n", path.c_str(), strerror(errno));
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continue;
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}
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while ((fdde = readdir(fdd.get())) != 0) {
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std::string fd_path = path + fdde->d_name;
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char link[FILENAME_MAX];
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int count = readlink(fd_path.c_str(), link, sizeof(link)-1);
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if (count >= 0) {
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link[count] = '\0';
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if (strncmp(link, "/cache/", 7) == 0) {
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if (files->erase(link) > 0) {
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printf("%s is open by %s\n", link, de->d_name);
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}
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}
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}
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}
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}
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return 0;
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}
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static std::set<std::string> FindExpendableFiles() {
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std::set<std::string> files;
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// We're allowed to delete unopened regular files in any of these
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// directories.
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const char* dirs[2] = {"/cache", "/cache/recovery/otatest"};
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for (size_t i = 0; i < sizeof(dirs)/sizeof(dirs[0]); ++i) {
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std::unique_ptr<DIR, decltype(&closedir)> d(opendir(dirs[i]), closedir);
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if (!d) {
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printf("error opening %s: %s\n", dirs[i], strerror(errno));
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continue;
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}
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// Look for regular files in the directory (not in any subdirectories).
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struct dirent* de;
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while ((de = readdir(d.get())) != 0) {
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std::string path = std::string(dirs[i]) + "/" + de->d_name;
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// We can't delete CACHE_TEMP_SOURCE; if it's there we might have
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// restarted during installation and could be depending on it to
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// be there.
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if (path == CACHE_TEMP_SOURCE) {
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continue;
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}
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struct stat st;
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if (stat(path.c_str(), &st) == 0 && S_ISREG(st.st_mode)) {
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files.insert(path);
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}
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}
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}
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printf("%zu regular files in deletable directories\n", files.size());
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if (EliminateOpenFiles(&files) < 0) {
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return std::set<std::string>();
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}
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return files;
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}
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int MakeFreeSpaceOnCache(size_t bytes_needed) {
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size_t free_now = FreeSpaceForFile("/cache");
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printf("%zu bytes free on /cache (%zu needed)\n", free_now, bytes_needed);
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if (free_now >= bytes_needed) {
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return 0;
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}
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std::set<std::string> files = FindExpendableFiles();
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if (files.empty()) {
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// nothing we can delete to free up space!
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printf("no files can be deleted to free space on /cache\n");
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return -1;
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}
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// We could try to be smarter about which files to delete: the
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// biggest ones? the smallest ones that will free up enough space?
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// the oldest? the newest?
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//
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// Instead, we'll be dumb.
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for (const auto& file : files) {
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unlink(file.c_str());
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free_now = FreeSpaceForFile("/cache");
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printf("deleted %s; now %zu bytes free\n", file.c_str(), free_now);
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if (free_now < bytes_needed) {
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break;
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}
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}
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return (free_now >= bytes_needed) ? 0 : -1;
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}
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