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Tao Baoba9a42a2015-06-23 23:23:33 -07001/*
2 * Copyright (C) 2010 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
Doug Zongker512536a2010-02-17 16:11:44 -080017#include <errno.h>
18#include <libgen.h>
19#include <stdio.h>
20#include <stdlib.h>
21#include <string.h>
22#include <sys/stat.h>
23#include <sys/statfs.h>
24#include <unistd.h>
25#include <dirent.h>
26#include <ctype.h>
27
Yabin Cuid483c202016-02-03 17:08:52 -080028#include <memory>
29#include <set>
30#include <string>
31
32#include <android-base/parseint.h>
33#include <android-base/stringprintf.h>
34
Tao Baod80a9982016-03-03 11:43:47 -080035#include "applypatch/applypatch.h"
Doug Zongker512536a2010-02-17 16:11:44 -080036
Yabin Cuid483c202016-02-03 17:08:52 -080037static int EliminateOpenFiles(std::set<std::string>* files) {
38 std::unique_ptr<DIR, decltype(&closedir)> d(opendir("/proc"), closedir);
39 if (!d) {
Doug Zongker512536a2010-02-17 16:11:44 -080040 printf("error opening /proc: %s\n", strerror(errno));
41 return -1;
42 }
Yabin Cuid483c202016-02-03 17:08:52 -080043 struct dirent* de;
44 while ((de = readdir(d.get())) != 0) {
45 unsigned int pid;
46 if (!android::base::ParseUint(de->d_name, &pid)) {
47 continue;
48 }
49 std::string path = android::base::StringPrintf("/proc/%s/fd/", de->d_name);
Doug Zongker512536a2010-02-17 16:11:44 -080050
Doug Zongker512536a2010-02-17 16:11:44 -080051 struct dirent* fdde;
Yabin Cuid483c202016-02-03 17:08:52 -080052 std::unique_ptr<DIR, decltype(&closedir)> fdd(opendir(path.c_str()), closedir);
53 if (!fdd) {
54 printf("error opening %s: %s\n", path.c_str(), strerror(errno));
Doug Zongker512536a2010-02-17 16:11:44 -080055 continue;
56 }
Yabin Cuid483c202016-02-03 17:08:52 -080057 while ((fdde = readdir(fdd.get())) != 0) {
58 std::string fd_path = path + fdde->d_name;
Doug Zongker512536a2010-02-17 16:11:44 -080059 char link[FILENAME_MAX];
Doug Zongker512536a2010-02-17 16:11:44 -080060
Yabin Cuid483c202016-02-03 17:08:52 -080061 int count = readlink(fd_path.c_str(), link, sizeof(link)-1);
Doug Zongker512536a2010-02-17 16:11:44 -080062 if (count >= 0) {
63 link[count] = '\0';
Doug Zongker512536a2010-02-17 16:11:44 -080064 if (strncmp(link, "/cache/", 7) == 0) {
Yabin Cuid483c202016-02-03 17:08:52 -080065 if (files->erase(link) > 0) {
66 printf("%s is open by %s\n", link, de->d_name);
Doug Zongker512536a2010-02-17 16:11:44 -080067 }
68 }
69 }
70 }
Doug Zongker512536a2010-02-17 16:11:44 -080071 }
Doug Zongker512536a2010-02-17 16:11:44 -080072 return 0;
73}
74
Yabin Cuid483c202016-02-03 17:08:52 -080075static std::set<std::string> FindExpendableFiles() {
76 std::set<std::string> files;
Doug Zongker512536a2010-02-17 16:11:44 -080077 // We're allowed to delete unopened regular files in any of these
78 // directories.
79 const char* dirs[2] = {"/cache", "/cache/recovery/otatest"};
80
Tao Baoba9a42a2015-06-23 23:23:33 -070081 for (size_t i = 0; i < sizeof(dirs)/sizeof(dirs[0]); ++i) {
Yabin Cuid483c202016-02-03 17:08:52 -080082 std::unique_ptr<DIR, decltype(&closedir)> d(opendir(dirs[i]), closedir);
83 if (!d) {
Doug Zongker512536a2010-02-17 16:11:44 -080084 printf("error opening %s: %s\n", dirs[i], strerror(errno));
85 continue;
86 }
87
88 // Look for regular files in the directory (not in any subdirectories).
Yabin Cuid483c202016-02-03 17:08:52 -080089 struct dirent* de;
90 while ((de = readdir(d.get())) != 0) {
91 std::string path = std::string(dirs[i]) + "/" + de->d_name;
Doug Zongker512536a2010-02-17 16:11:44 -080092
Tianjie Xua88cc542017-10-25 13:16:54 -070093 // We can't delete cache_temp_source; if it's there we might have restarted during
94 // installation and could be depending on it to be there.
95 if (path == cache_temp_source) {
Yabin Cuid483c202016-02-03 17:08:52 -080096 continue;
97 }
Doug Zongker512536a2010-02-17 16:11:44 -080098
99 struct stat st;
Yabin Cuid483c202016-02-03 17:08:52 -0800100 if (stat(path.c_str(), &st) == 0 && S_ISREG(st.st_mode)) {
101 files.insert(path);
Doug Zongker512536a2010-02-17 16:11:44 -0800102 }
103 }
Doug Zongker512536a2010-02-17 16:11:44 -0800104 }
105
Yabin Cuid483c202016-02-03 17:08:52 -0800106 printf("%zu regular files in deletable directories\n", files.size());
107 if (EliminateOpenFiles(&files) < 0) {
108 return std::set<std::string>();
Doug Zongker512536a2010-02-17 16:11:44 -0800109 }
Yabin Cuid483c202016-02-03 17:08:52 -0800110 return files;
Doug Zongker512536a2010-02-17 16:11:44 -0800111}
112
113int MakeFreeSpaceOnCache(size_t bytes_needed) {
114 size_t free_now = FreeSpaceForFile("/cache");
Tao Baoba9a42a2015-06-23 23:23:33 -0700115 printf("%zu bytes free on /cache (%zu needed)\n", free_now, bytes_needed);
Doug Zongker512536a2010-02-17 16:11:44 -0800116
117 if (free_now >= bytes_needed) {
118 return 0;
119 }
Yabin Cuid483c202016-02-03 17:08:52 -0800120 std::set<std::string> files = FindExpendableFiles();
121 if (files.empty()) {
Doug Zongker512536a2010-02-17 16:11:44 -0800122 // nothing we can delete to free up space!
123 printf("no files can be deleted to free space on /cache\n");
124 return -1;
125 }
126
127 // We could try to be smarter about which files to delete: the
128 // biggest ones? the smallest ones that will free up enough space?
129 // the oldest? the newest?
130 //
131 // Instead, we'll be dumb.
132
Yabin Cuid483c202016-02-03 17:08:52 -0800133 for (const auto& file : files) {
134 unlink(file.c_str());
135 free_now = FreeSpaceForFile("/cache");
136 printf("deleted %s; now %zu bytes free\n", file.c_str(), free_now);
137 if (free_now < bytes_needed) {
138 break;
Doug Zongker512536a2010-02-17 16:11:44 -0800139 }
140 }
Doug Zongker512536a2010-02-17 16:11:44 -0800141 return (free_now >= bytes_needed) ? 0 : -1;
142}