1 /*
2 * Copyright (C) 2008 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
17 #include <dirent.h>
18 #include <errno.h>
19 #include <fcntl.h>
20 #include <stdio.h>
21 #include <stdlib.h>
22 #include <string.h>
23 #include <unistd.h>
24
25 #include <linux/fs.h>
26 #include <sys/ioctl.h>
27 #include <sys/mman.h>
28 #include <sys/mount.h>
29 #include <sys/stat.h>
30 #include <sys/types.h>
31 #include <sys/wait.h>
32
33 #include <linux/kdev_t.h>
34
35 #include <android-base/logging.h>
36 #include <android-base/stringprintf.h>
37 #include <selinux/selinux.h>
38
39 #include <logwrap/logwrap.h>
40
41 #include "Utils.h"
42 #include "Vfat.h"
43 #include "VoldUtil.h"
44
45 using android::base::StringPrintf;
46
47 namespace android {
48 namespace vold {
49 namespace vfat {
50
51 static const char* kMkfsPath = "/system/bin/newfs_msdos";
52 static const char* kFsckPath = "/system/bin/fsck_msdos";
53
IsSupported()54 bool IsSupported() {
55 return access(kMkfsPath, X_OK) == 0 && access(kFsckPath, X_OK) == 0 &&
56 IsFilesystemSupported("vfat");
57 }
58
Check(const std::string & source)59 status_t Check(const std::string& source) {
60 int pass = 1;
61 int rc = 0;
62 do {
63 std::vector<std::string> cmd;
64 cmd.push_back(kFsckPath);
65 cmd.push_back("-p");
66 cmd.push_back("-f");
67 cmd.push_back("-y");
68 cmd.push_back(source);
69
70 // Fat devices are currently always untrusted
71 rc = ForkExecvp(cmd, nullptr, sFsckUntrustedContext);
72
73 if (rc < 0) {
74 LOG(ERROR) << "Filesystem check failed due to logwrap error";
75 errno = EIO;
76 return -1;
77 }
78
79 switch (rc) {
80 case 0:
81 LOG(INFO) << "Filesystem check completed OK";
82 return 0;
83
84 case 2:
85 LOG(ERROR) << "Filesystem check failed (not a FAT filesystem)";
86 errno = ENODATA;
87 return -1;
88
89 case 4:
90 if (pass++ <= 3) {
91 LOG(WARNING) << "Filesystem modified - rechecking (pass " << pass << ")";
92 continue;
93 }
94 LOG(ERROR) << "Failing check after too many rechecks";
95 errno = EIO;
96 return -1;
97
98 case 8:
99 LOG(ERROR) << "Filesystem check failed (no filesystem)";
100 errno = ENODATA;
101 return -1;
102
103 default:
104 LOG(ERROR) << "Filesystem check failed (unknown exit code " << rc << ")";
105 errno = EIO;
106 return -1;
107 }
108 } while (0);
109
110 return 0;
111 }
112
Mount(const std::string & source,const std::string & target,bool ro,bool remount,bool executable,int ownerUid,int ownerGid,int permMask,bool createLost)113 status_t Mount(const std::string& source, const std::string& target, bool ro, bool remount,
114 bool executable, int ownerUid, int ownerGid, int permMask, bool createLost) {
115 int rc;
116 unsigned long flags;
117
118 const char* c_source = source.c_str();
119 const char* c_target = target.c_str();
120
121 flags = MS_NODEV | MS_NOSUID | MS_DIRSYNC | MS_NOATIME;
122
123 flags |= (executable ? 0 : MS_NOEXEC);
124 flags |= (ro ? MS_RDONLY : 0);
125 flags |= (remount ? MS_REMOUNT : 0);
126
127 auto mountData =
128 android::base::StringPrintf("utf8,uid=%d,gid=%d,fmask=%o,dmask=%o,shortname=mixed",
129 ownerUid, ownerGid, permMask, permMask);
130
131 rc = mount(c_source, c_target, "vfat", flags, mountData.c_str());
132
133 if (rc && errno == EROFS) {
134 LOG(ERROR) << source << " appears to be a read only filesystem - retrying mount RO";
135 flags |= MS_RDONLY;
136 rc = mount(c_source, c_target, "vfat", flags, mountData.c_str());
137 }
138
139 if (rc == 0 && createLost) {
140 auto lost_path = android::base::StringPrintf("%s/LOST.DIR", target.c_str());
141 if (access(lost_path.c_str(), F_OK)) {
142 /*
143 * Create a LOST.DIR in the root so we have somewhere to put
144 * lost cluster chains (fsck_msdos doesn't currently do this)
145 */
146 if (mkdir(lost_path.c_str(), 0755)) {
147 PLOG(ERROR) << "Unable to create LOST.DIR";
148 }
149 }
150 }
151
152 return rc;
153 }
154
Format(const std::string & source,unsigned long numSectors)155 status_t Format(const std::string& source, unsigned long numSectors) {
156 std::vector<std::string> cmd;
157 cmd.push_back(kMkfsPath);
158 cmd.push_back("-O");
159 cmd.push_back("android");
160 cmd.push_back("-A");
161
162 if (numSectors) {
163 cmd.push_back("-s");
164 cmd.push_back(StringPrintf("%lu", numSectors));
165 }
166
167 cmd.push_back(source);
168
169 int rc = ForkExecvp(cmd);
170 if (rc < 0) {
171 LOG(ERROR) << "Filesystem format failed due to logwrap error";
172 errno = EIO;
173 return -1;
174 }
175
176 if (rc == 0) {
177 LOG(INFO) << "Filesystem formatted OK";
178 return 0;
179 } else {
180 LOG(ERROR) << "Format failed (unknown exit code " << rc << ")";
181 errno = EIO;
182 return -1;
183 }
184 return 0;
185 }
186
187 } // namespace vfat
188 } // namespace vold
189 } // namespace android
190