1 /*
2  * Copyright (C) 2018 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_NDEBUG 0
18 #define LOG_TAG "FileSource"
19 #include <utils/Log.h>
20 
21 #include <datasource/FileSource.h>
22 #include <media/stagefright/foundation/ADebug.h>
23 #include <media/stagefright/FoundationUtils.h>
24 #include <sys/types.h>
25 #include <unistd.h>
26 #include <sys/types.h>
27 #include <sys/stat.h>
28 #include <fcntl.h>
29 
30 namespace android {
31 
FileSource(const char * filename)32 FileSource::FileSource(const char *filename)
33     : mFd(-1),
34       mOffset(0),
35       mLength(-1),
36       mName("<null>") {
37 
38     if (filename) {
39         mName = String8::format("FileSource(%s)", filename);
40     }
41     ALOGV("%s", filename);
42     mFd = open(filename, O_LARGEFILE | O_RDONLY);
43 
44     if (mFd >= 0) {
45         mLength = lseek64(mFd, 0, SEEK_END);
46     } else {
47         ALOGE("Failed to open file '%s'. (%s)", filename, strerror(errno));
48     }
49 }
50 
FileSource(int fd,int64_t offset,int64_t length)51 FileSource::FileSource(int fd, int64_t offset, int64_t length)
52     : mFd(fd),
53       mOffset(offset),
54       mLength(length),
55       mName("<null>") {
56     ALOGV("fd=%d (%s), offset=%lld, length=%lld",
57             fd, nameForFd(fd).c_str(), (long long) offset, (long long) length);
58 
59     if (mOffset < 0) {
60         mOffset = 0;
61     }
62     if (mLength < 0) {
63         mLength = 0;
64     }
65     if (mLength > INT64_MAX - mOffset) {
66         mLength = INT64_MAX - mOffset;
67     }
68     struct stat s;
69     if (fstat(fd, &s) == 0) {
70         if (mOffset > s.st_size) {
71             mOffset = s.st_size;
72             mLength = 0;
73         }
74         if (mOffset + mLength > s.st_size) {
75             mLength = s.st_size - mOffset;
76         }
77     }
78     if (mOffset != offset || mLength != length) {
79         ALOGW("offset/length adjusted from %lld/%lld to %lld/%lld",
80                 (long long) offset, (long long) length,
81                 (long long) mOffset, (long long) mLength);
82     }
83 
84     mName = String8::format(
85             "FileSource(fd(%s), %lld, %lld)",
86             nameForFd(fd).c_str(),
87             (long long) mOffset,
88             (long long) mLength);
89 
90 }
91 
~FileSource()92 FileSource::~FileSource() {
93     if (mFd >= 0) {
94         ::close(mFd);
95         mFd = -1;
96     }
97 }
98 
initCheck() const99 status_t FileSource::initCheck() const {
100     return mFd >= 0 ? OK : NO_INIT;
101 }
102 
readAt(off64_t offset,void * data,size_t size)103 ssize_t FileSource::readAt(off64_t offset, void *data, size_t size) {
104     if (mFd < 0) {
105         return NO_INIT;
106     }
107 
108     Mutex::Autolock autoLock(mLock);
109     if (mLength >= 0) {
110         if (offset >= mLength) {
111             return 0;  // read beyond EOF.
112         }
113         uint64_t numAvailable = mLength - offset;
114         if ((uint64_t)size > numAvailable) {
115             size = numAvailable;
116         }
117     }
118     return readAt_l(offset, data, size);
119 }
120 
readAt_l(off64_t offset,void * data,size_t size)121 ssize_t FileSource::readAt_l(off64_t offset, void *data, size_t size) {
122     off64_t result = lseek64(mFd, offset + mOffset, SEEK_SET);
123     if (result == -1) {
124         ALOGE("seek to %lld failed", (long long)(offset + mOffset));
125         return UNKNOWN_ERROR;
126     }
127 
128     return ::read(mFd, data, size);
129 }
130 
getSize(off64_t * size)131 status_t FileSource::getSize(off64_t *size) {
132     Mutex::Autolock autoLock(mLock);
133 
134     if (mFd < 0) {
135         return NO_INIT;
136     }
137 
138     *size = mLength;
139 
140     return OK;
141 }
142 
143 }  // namespace android
144