1 /*
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 
17 #define LOG_TAG "MtpUtils"
18 
19 #include <android-base/logging.h>
20 #include <android-base/unique_fd.h>
21 #include <dirent.h>
22 #include <fcntl.h>
23 #include <string>
24 #include <sys/sendfile.h>
25 #include <sys/stat.h>
26 #include <sys/types.h>
27 #include <stdio.h>
28 #include <time.h>
29 #include <unistd.h>
30 
31 #include "MtpUtils.h"
32 
33 using namespace std;
34 
35 namespace android {
36 
37 constexpr unsigned long FILE_COPY_SIZE = 262144;
38 
access_ok(const char * path)39 static void access_ok(const char *path) {
40     if (access(path, F_OK) == -1) {
41         // Ignore. Failure could be common in cases of delete where
42         // the metadata was updated through other paths.
43     }
44 }
45 
46 /*
47 DateTime strings follow a compatible subset of the definition found in ISO 8601, and
48 take the form of a Unicode string formatted as: "YYYYMMDDThhmmss.s". In this
49 representation, YYYY shall be replaced by the year, MM replaced by the month (01-12),
50 DD replaced by the day (01-31), T is a constant character 'T' delimiting time from date,
51 hh is replaced by the hour (00-23), mm is replaced by the minute (00-59), and ss by the
52 second (00-59). The ".s" is optional, and represents tenths of a second.
53 This is followed by a UTC offset given as "[+-]zzzz" or the literal "Z", meaning UTC.
54 */
55 
parseDateTime(const char * dateTime,time_t & outSeconds)56 bool parseDateTime(const char* dateTime, time_t& outSeconds) {
57     int year, month, day, hour, minute, second;
58     if (sscanf(dateTime, "%04d%02d%02dT%02d%02d%02d",
59                &year, &month, &day, &hour, &minute, &second) != 6)
60         return false;
61 
62     // skip optional tenth of second
63     const char* tail = dateTime + 15;
64     if (tail[0] == '.' && tail[1]) tail += 2;
65 
66     // FIXME: "Z" means UTC, but non-"Z" doesn't mean local time.
67     // It might be that you're in Asia/Seoul on vacation and your Android
68     // device has noticed this via the network, but your camera was set to
69     // America/Los_Angeles once when you bought it and doesn't know where
70     // it is right now, so the camera says "20160106T081700-0800" but we
71     // just ignore the "-0800" and assume local time which is actually "+0900".
72     // I think to support this (without switching to Java or using icu4c)
73     // you'd want to always use timegm(3) and then manually add/subtract
74     // the UTC offset parsed from the string (taking care of wrapping).
75     // mktime(3) ignores the tm_gmtoff field, so you can't let it do the work.
76     bool useUTC = (tail[0] == 'Z');
77 
78     struct tm tm = {};
79     tm.tm_sec = second;
80     tm.tm_min = minute;
81     tm.tm_hour = hour;
82     tm.tm_mday = day;
83     tm.tm_mon = month - 1;  // mktime uses months in 0 - 11 range
84     tm.tm_year = year - 1900;
85     tm.tm_isdst = -1;
86     outSeconds = useUTC ? timegm(&tm) : mktime(&tm);
87 
88     return true;
89 }
90 
formatDateTime(time_t seconds,char * buffer,int bufferLength)91 void formatDateTime(time_t seconds, char* buffer, int bufferLength) {
92     struct tm tm;
93 
94     localtime_r(&seconds, &tm);
95     snprintf(buffer, bufferLength, "%04d%02d%02dT%02d%02d%02d",
96         tm.tm_year + 1900,
97         tm.tm_mon + 1, // localtime_r uses months in 0 - 11 range
98         tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec);
99 }
100 
makeFolder(const char * path)101 int makeFolder(const char *path) {
102     mode_t mask = umask(0);
103     int ret = mkdir((const char *)path, DIR_PERM);
104     umask(mask);
105     if (ret && ret != -EEXIST) {
106         PLOG(ERROR) << "Failed to create folder " << path;
107         ret = -1;
108     } else {
109         chown((const char *)path, getuid(), FILE_GROUP);
110     }
111     access_ok(path);
112     return ret;
113 }
114 
115 /**
116  * Copies target path and all children to destination path.
117  *
118  * Returns 0 on success or a negative value indicating number of failures
119  */
copyRecursive(const char * fromPath,const char * toPath)120 int copyRecursive(const char *fromPath, const char *toPath) {
121     int ret = 0;
122     string fromPathStr(fromPath);
123     string toPathStr(toPath);
124 
125     DIR* dir = opendir(fromPath);
126     if (!dir) {
127         PLOG(ERROR) << "opendir " << fromPath << " failed";
128         return -1;
129     }
130     if (fromPathStr[fromPathStr.size()-1] != '/')
131         fromPathStr += '/';
132     if (toPathStr[toPathStr.size()-1] != '/')
133         toPathStr += '/';
134 
135     struct dirent* entry;
136     while ((entry = readdir(dir))) {
137         const char* name = entry->d_name;
138 
139         // ignore "." and ".."
140         if (name[0] == '.' && (name[1] == 0 || (name[1] == '.' && name[2] == 0))) {
141             continue;
142         }
143         string oldFile = fromPathStr + name;
144         string newFile = toPathStr + name;
145 
146         if (entry->d_type == DT_DIR) {
147             ret += makeFolder(newFile.c_str());
148             ret += copyRecursive(oldFile.c_str(), newFile.c_str());
149         } else {
150             ret += copyFile(oldFile.c_str(), newFile.c_str());
151         }
152     }
153     return ret;
154 }
155 
copyFile(const char * fromPath,const char * toPath)156 int copyFile(const char *fromPath, const char *toPath) {
157     auto start = std::chrono::steady_clock::now();
158 
159     android::base::unique_fd fromFd(open(fromPath, O_RDONLY));
160     if (fromFd == -1) {
161         PLOG(ERROR) << "Failed to open copy from " << fromPath;
162         return -1;
163     }
164     android::base::unique_fd toFd(open(toPath, O_CREAT | O_WRONLY, FILE_PERM));
165     if (toFd == -1) {
166         PLOG(ERROR) << "Failed to open copy to " << toPath;
167         return -1;
168     }
169     off_t offset = 0;
170 
171     struct stat sstat = {};
172     if (stat(fromPath, &sstat) == -1)
173         return -1;
174 
175     off_t length = sstat.st_size;
176     int ret = 0;
177 
178     while (offset < length) {
179         ssize_t transfer_length = std::min(length - offset, (off_t) FILE_COPY_SIZE);
180         ret = sendfile(toFd, fromFd, &offset, transfer_length);
181         if (ret != transfer_length) {
182             ret = -1;
183             PLOG(ERROR) << "Copying failed!";
184             break;
185         }
186     }
187     auto end = std::chrono::steady_clock::now();
188     std::chrono::duration<double> diff = end - start;
189     LOG(DEBUG) << "Copied a file with MTP. Time: " << diff.count() << " s, Size: " << length <<
190         ", Rate: " << ((double) length) / diff.count() << " bytes/s";
191     chown(toPath, getuid(), FILE_GROUP);
192     access_ok(toPath);
193     return ret == -1 ? -1 : 0;
194 }
195 
deleteRecursive(const char * path)196 void deleteRecursive(const char* path) {
197     string pathStr(path);
198     if (pathStr[pathStr.size()-1] != '/') {
199         pathStr += '/';
200     }
201 
202     DIR* dir = opendir(path);
203     if (!dir) {
204         PLOG(ERROR) << "opendir " << path << " failed";
205         return;
206     }
207 
208     struct dirent* entry;
209     while ((entry = readdir(dir))) {
210         const char* name = entry->d_name;
211 
212         // ignore "." and ".."
213         if (name[0] == '.' && (name[1] == 0 || (name[1] == '.' && name[2] == 0))) {
214             continue;
215         }
216         string childPath = pathStr + name;
217         int success;
218         if (entry->d_type == DT_DIR) {
219             deleteRecursive(childPath.c_str());
220             success = rmdir(childPath.c_str());
221         } else {
222             success = unlink(childPath.c_str());
223         }
224         access_ok(childPath.c_str());
225         if (success == -1)
226             PLOG(ERROR) << "Deleting path " << childPath << " failed";
227     }
228     closedir(dir);
229 }
230 
deletePath(const char * path)231 bool deletePath(const char* path) {
232     struct stat statbuf;
233     int success;
234     if (stat(path, &statbuf) == 0) {
235         if (S_ISDIR(statbuf.st_mode)) {
236             // rmdir will fail if the directory is non empty, so
237             // there is no need to keep errors from deleteRecursive
238             deleteRecursive(path);
239             success = rmdir(path);
240         } else {
241             success = unlink(path);
242         }
243     } else {
244         PLOG(ERROR) << "deletePath stat failed for " << path;
245         return false;
246     }
247     if (success == -1)
248         PLOG(ERROR) << "Deleting path " << path << " failed";
249     access_ok(path);
250     return success == 0;
251 }
252 
renameTo(const char * oldPath,const char * newPath)253 int renameTo(const char *oldPath, const char *newPath) {
254     int ret = rename(oldPath, newPath);
255     access_ok(oldPath);
256     access_ok(newPath);
257     return ret;
258 }
259 
260 // Calls access(2) on the path to update underlying filesystems,
261 // then closes the fd.
closeObjFd(int fd,const char * path)262 void closeObjFd(int fd, const char *path) {
263     close(fd);
264     access_ok(path);
265 }
266 
267 }  // namespace android
268