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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 <errno.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 <dirent.h>
#include <ctype.h>
#include <memory>
#include <set>
#include <string>
#include <android-base/parseint.h>
#include <android-base/stringprintf.h>
#include "applypatch/applypatch.h"
static int EliminateOpenFiles(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 (strncmp(link, "/cache/", 7) == 0) {
if (files->erase(link) > 0) {
printf("%s is open by %s\n", link, de->d_name);
}
}
}
}
}
return 0;
}
static std::set<std::string> FindExpendableFiles() {
std::set<std::string> files;
// We're allowed to delete unopened regular files in any of these
// directories.
const char* dirs[2] = {"/cache", "/cache/recovery/otatest"};
for (size_t i = 0; i < sizeof(dirs)/sizeof(dirs[0]); ++i) {
std::unique_ptr<DIR, decltype(&closedir)> d(opendir(dirs[i]), closedir);
if (!d) {
printf("error opening %s: %s\n", dirs[i], strerror(errno));
continue;
}
// Look for regular files in the directory (not in any subdirectories).
struct dirent* de;
while ((de = readdir(d.get())) != 0) {
std::string path = std::string(dirs[i]) + "/" + 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 == cache_temp_source) {
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 directories\n", files.size());
if (EliminateOpenFiles(&files) < 0) {
return std::set<std::string>();
}
return files;
}
int MakeFreeSpaceOnCache(size_t bytes_needed) {
size_t free_now = FreeSpaceForFile("/cache");
printf("%zu bytes free on /cache (%zu needed)\n", free_now, bytes_needed);
if (free_now >= bytes_needed) {
return 0;
}
std::set<std::string> files = FindExpendableFiles();
if (files.empty()) {
// nothing we can delete to free up space!
printf("no files can be deleted to free space on /cache\n");
return -1;
}
// We could try to be smarter about which files to delete: the
// biggest ones? the smallest ones that will free up enough space?
// the oldest? the newest?
//
// Instead, we'll be dumb.
for (const auto& file : files) {
unlink(file.c_str());
free_now = FreeSpaceForFile("/cache");
printf("deleted %s; now %zu bytes free\n", file.c_str(), free_now);
if (free_now < bytes_needed) {
break;
}
}
return (free_now >= bytes_needed) ? 0 : -1;
}
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