1*f40fafd4SAndroid Build Coastguard Worker /*
2*f40fafd4SAndroid Build Coastguard Worker * Copyright (C) 2017 The Android Open Source Project
3*f40fafd4SAndroid Build Coastguard Worker *
4*f40fafd4SAndroid Build Coastguard Worker * Licensed under the Apache License, Version 2.0 (the "License");
5*f40fafd4SAndroid Build Coastguard Worker * you may not use this file except in compliance with the License.
6*f40fafd4SAndroid Build Coastguard Worker * You may obtain a copy of the License at
7*f40fafd4SAndroid Build Coastguard Worker *
8*f40fafd4SAndroid Build Coastguard Worker * http://www.apache.org/licenses/LICENSE-2.0
9*f40fafd4SAndroid Build Coastguard Worker *
10*f40fafd4SAndroid Build Coastguard Worker * Unless required by applicable law or agreed to in writing, software
11*f40fafd4SAndroid Build Coastguard Worker * distributed under the License is distributed on an "AS IS" BASIS,
12*f40fafd4SAndroid Build Coastguard Worker * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13*f40fafd4SAndroid Build Coastguard Worker * See the License for the specific language governing permissions and
14*f40fafd4SAndroid Build Coastguard Worker * limitations under the License.
15*f40fafd4SAndroid Build Coastguard Worker */
16*f40fafd4SAndroid Build Coastguard Worker
17*f40fafd4SAndroid Build Coastguard Worker #include "FileDeviceUtils.h"
18*f40fafd4SAndroid Build Coastguard Worker
19*f40fafd4SAndroid Build Coastguard Worker #include <errno.h>
20*f40fafd4SAndroid Build Coastguard Worker #include <fcntl.h>
21*f40fafd4SAndroid Build Coastguard Worker #include <linux/fiemap.h>
22*f40fafd4SAndroid Build Coastguard Worker #include <linux/fs.h>
23*f40fafd4SAndroid Build Coastguard Worker #include <mntent.h>
24*f40fafd4SAndroid Build Coastguard Worker #include <stdio.h>
25*f40fafd4SAndroid Build Coastguard Worker #include <stdlib.h>
26*f40fafd4SAndroid Build Coastguard Worker #include <sys/stat.h>
27*f40fafd4SAndroid Build Coastguard Worker #include <sys/types.h>
28*f40fafd4SAndroid Build Coastguard Worker
29*f40fafd4SAndroid Build Coastguard Worker #include <android-base/file.h>
30*f40fafd4SAndroid Build Coastguard Worker #include <android-base/logging.h>
31*f40fafd4SAndroid Build Coastguard Worker #include <android-base/unique_fd.h>
32*f40fafd4SAndroid Build Coastguard Worker
33*f40fafd4SAndroid Build Coastguard Worker namespace {
34*f40fafd4SAndroid Build Coastguard Worker
35*f40fafd4SAndroid Build Coastguard Worker std::unique_ptr<struct fiemap> alloc_fiemap(uint32_t extent_count);
36*f40fafd4SAndroid Build Coastguard Worker
37*f40fafd4SAndroid Build Coastguard Worker }
38*f40fafd4SAndroid Build Coastguard Worker
39*f40fafd4SAndroid Build Coastguard Worker namespace android {
40*f40fafd4SAndroid Build Coastguard Worker namespace vold {
41*f40fafd4SAndroid Build Coastguard Worker
42*f40fafd4SAndroid Build Coastguard Worker // Given a file path, look for the corresponding block device in /proc/mount
BlockDeviceForPath(const std::string & path)43*f40fafd4SAndroid Build Coastguard Worker std::string BlockDeviceForPath(const std::string& path) {
44*f40fafd4SAndroid Build Coastguard Worker std::unique_ptr<FILE, int (*)(FILE*)> mnts(setmntent("/proc/mounts", "re"), endmntent);
45*f40fafd4SAndroid Build Coastguard Worker if (!mnts) {
46*f40fafd4SAndroid Build Coastguard Worker PLOG(ERROR) << "Unable to open /proc/mounts";
47*f40fafd4SAndroid Build Coastguard Worker return "";
48*f40fafd4SAndroid Build Coastguard Worker }
49*f40fafd4SAndroid Build Coastguard Worker std::string result;
50*f40fafd4SAndroid Build Coastguard Worker size_t best_length = 0;
51*f40fafd4SAndroid Build Coastguard Worker struct mntent* mnt; // getmntent returns a thread local, so it's safe.
52*f40fafd4SAndroid Build Coastguard Worker while ((mnt = getmntent(mnts.get())) != nullptr) {
53*f40fafd4SAndroid Build Coastguard Worker auto l = strlen(mnt->mnt_dir);
54*f40fafd4SAndroid Build Coastguard Worker if (l > best_length && path.size() > l && path[l] == '/' &&
55*f40fafd4SAndroid Build Coastguard Worker path.compare(0, l, mnt->mnt_dir) == 0) {
56*f40fafd4SAndroid Build Coastguard Worker result = mnt->mnt_fsname;
57*f40fafd4SAndroid Build Coastguard Worker best_length = l;
58*f40fafd4SAndroid Build Coastguard Worker }
59*f40fafd4SAndroid Build Coastguard Worker }
60*f40fafd4SAndroid Build Coastguard Worker if (result.empty()) {
61*f40fafd4SAndroid Build Coastguard Worker LOG(ERROR) << "Didn't find a mountpoint to match path " << path;
62*f40fafd4SAndroid Build Coastguard Worker return "";
63*f40fafd4SAndroid Build Coastguard Worker }
64*f40fafd4SAndroid Build Coastguard Worker return result;
65*f40fafd4SAndroid Build Coastguard Worker }
66*f40fafd4SAndroid Build Coastguard Worker
PathFiemap(const std::string & path,uint32_t extent_count)67*f40fafd4SAndroid Build Coastguard Worker std::unique_ptr<struct fiemap> PathFiemap(const std::string& path, uint32_t extent_count) {
68*f40fafd4SAndroid Build Coastguard Worker android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(path.c_str(), O_RDONLY | O_CLOEXEC, 0)));
69*f40fafd4SAndroid Build Coastguard Worker if (fd == -1) {
70*f40fafd4SAndroid Build Coastguard Worker if (errno == ENOENT) {
71*f40fafd4SAndroid Build Coastguard Worker PLOG(DEBUG) << "Unable to open " << path;
72*f40fafd4SAndroid Build Coastguard Worker } else {
73*f40fafd4SAndroid Build Coastguard Worker PLOG(ERROR) << "Unable to open " << path;
74*f40fafd4SAndroid Build Coastguard Worker }
75*f40fafd4SAndroid Build Coastguard Worker return nullptr;
76*f40fafd4SAndroid Build Coastguard Worker }
77*f40fafd4SAndroid Build Coastguard Worker auto fiemap = alloc_fiemap(extent_count);
78*f40fafd4SAndroid Build Coastguard Worker if (ioctl(fd.get(), FS_IOC_FIEMAP, fiemap.get()) != 0) {
79*f40fafd4SAndroid Build Coastguard Worker PLOG(ERROR) << "Unable to FIEMAP " << path;
80*f40fafd4SAndroid Build Coastguard Worker return nullptr;
81*f40fafd4SAndroid Build Coastguard Worker }
82*f40fafd4SAndroid Build Coastguard Worker auto mapped = fiemap->fm_mapped_extents;
83*f40fafd4SAndroid Build Coastguard Worker if (mapped < 1 || mapped > extent_count) {
84*f40fafd4SAndroid Build Coastguard Worker LOG(ERROR) << "Extent count not in bounds 1 <= " << mapped << " <= " << extent_count
85*f40fafd4SAndroid Build Coastguard Worker << " in " << path;
86*f40fafd4SAndroid Build Coastguard Worker return nullptr;
87*f40fafd4SAndroid Build Coastguard Worker }
88*f40fafd4SAndroid Build Coastguard Worker return fiemap;
89*f40fafd4SAndroid Build Coastguard Worker }
90*f40fafd4SAndroid Build Coastguard Worker
91*f40fafd4SAndroid Build Coastguard Worker } // namespace vold
92*f40fafd4SAndroid Build Coastguard Worker } // namespace android
93*f40fafd4SAndroid Build Coastguard Worker
94*f40fafd4SAndroid Build Coastguard Worker namespace {
95*f40fafd4SAndroid Build Coastguard Worker
alloc_fiemap(uint32_t extent_count)96*f40fafd4SAndroid Build Coastguard Worker std::unique_ptr<struct fiemap> alloc_fiemap(uint32_t extent_count) {
97*f40fafd4SAndroid Build Coastguard Worker size_t allocsize = offsetof(struct fiemap, fm_extents[extent_count]);
98*f40fafd4SAndroid Build Coastguard Worker std::unique_ptr<struct fiemap> res(new (::operator new(allocsize)) struct fiemap);
99*f40fafd4SAndroid Build Coastguard Worker memset(res.get(), 0, allocsize);
100*f40fafd4SAndroid Build Coastguard Worker res->fm_start = 0;
101*f40fafd4SAndroid Build Coastguard Worker res->fm_length = UINT64_MAX;
102*f40fafd4SAndroid Build Coastguard Worker res->fm_flags = 0;
103*f40fafd4SAndroid Build Coastguard Worker res->fm_extent_count = extent_count;
104*f40fafd4SAndroid Build Coastguard Worker res->fm_mapped_extents = 0;
105*f40fafd4SAndroid Build Coastguard Worker return res;
106*f40fafd4SAndroid Build Coastguard Worker }
107*f40fafd4SAndroid Build Coastguard Worker
108*f40fafd4SAndroid Build Coastguard Worker } // namespace
109