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 = ForkExecvpTimeout(cmd, kUntrustedFsckSleepTime, sFsckUntrustedContext);
72 if (rc < 0) {
73 LOG(ERROR) << "Filesystem check failed due to fork error";
74 errno = EIO;
75 return -1;
76 }
77
78 switch (rc) {
79 case 0:
80 LOG(INFO) << "Filesystem check completed OK";
81 return 0;
82
83 case 1:
84 LOG(INFO) << "Failed to check filesystem";
85 return -1;
86
87 case 2:
88 LOG(ERROR) << "Filesystem check failed (not a FAT filesystem)";
89 errno = ENODATA;
90 return -1;
91
92 case 4:
93 if (pass++ <= 3) {
94 LOG(WARNING) << "Filesystem modified - rechecking (pass " << pass << ")";
95 continue;
96 }
97 LOG(ERROR) << "Failing check after too many rechecks";
98 errno = EIO;
99 return -1;
100
101 case 8:
102 LOG(ERROR) << "Filesystem check failed (no filesystem)";
103 errno = ENODATA;
104 return -1;
105
106 case ETIMEDOUT:
107 LOG(ERROR) << "Filesystem check timed out";
108 errno = ETIMEDOUT;
109 return -1;
110
111 default:
112 LOG(ERROR) << "Filesystem check failed (unknown exit code " << rc << ")";
113 errno = EIO;
114 return -1;
115 }
116 } while (0);
117
118 return 0;
119 }
120
Mount(const std::string & source,const std::string & target,bool ro,bool remount,bool executable,int ownerUid,int ownerGid,int permMask,bool createLost)121 status_t Mount(const std::string& source, const std::string& target, bool ro, bool remount,
122 bool executable, int ownerUid, int ownerGid, int permMask, bool createLost) {
123 int rc;
124 unsigned long flags;
125
126 const char* c_source = source.c_str();
127 const char* c_target = target.c_str();
128
129 flags = MS_NODEV | MS_NOSUID | MS_DIRSYNC | MS_NOATIME;
130
131 flags |= (executable ? 0 : MS_NOEXEC);
132 flags |= (ro ? MS_RDONLY : 0);
133 flags |= (remount ? MS_REMOUNT : 0);
134
135 auto mountData =
136 android::base::StringPrintf("utf8,uid=%d,gid=%d,fmask=%o,dmask=%o,shortname=mixed",
137 ownerUid, ownerGid, permMask, permMask);
138
139 rc = mount(c_source, c_target, "vfat", flags, mountData.c_str());
140
141 if (rc && errno == EROFS) {
142 LOG(ERROR) << source << " appears to be a read only filesystem - retrying mount RO";
143 flags |= MS_RDONLY;
144 rc = mount(c_source, c_target, "vfat", flags, mountData.c_str());
145 }
146
147 if (rc == 0 && createLost) {
148 auto lost_path = android::base::StringPrintf("%s/LOST.DIR", target.c_str());
149 if (access(lost_path.c_str(), F_OK)) {
150 /*
151 * Create a LOST.DIR in the root so we have somewhere to put
152 * lost cluster chains (fsck_msdos doesn't currently do this)
153 */
154 if (mkdir(lost_path.c_str(), 0755)) {
155 PLOG(ERROR) << "Unable to create LOST.DIR";
156 }
157 }
158 }
159
160 return rc;
161 }
162
Format(const std::string & source,unsigned long numSectors)163 status_t Format(const std::string& source, unsigned long numSectors) {
164 std::vector<std::string> cmd;
165 cmd.push_back(kMkfsPath);
166 cmd.push_back("-O");
167 cmd.push_back("android");
168 cmd.push_back("-A");
169
170 if (numSectors) {
171 cmd.push_back("-s");
172 cmd.push_back(StringPrintf("%lu", numSectors));
173 }
174
175 cmd.push_back(source);
176
177 int rc = ForkExecvp(cmd);
178 if (rc < 0) {
179 LOG(ERROR) << "Filesystem format failed due to logwrap error";
180 errno = EIO;
181 return -1;
182 }
183
184 if (rc == 0) {
185 LOG(INFO) << "Filesystem formatted OK";
186 return 0;
187 } else {
188 LOG(ERROR) << "Format failed (unknown exit code " << rc << ")";
189 errno = EIO;
190 return -1;
191 }
192 return 0;
193 }
194
195 } // namespace vfat
196 } // namespace vold
197 } // namespace android
198