1 /*
2  * Copyright (C) 2013, 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 "dictionary/utils/mmapped_buffer.h"
18 
19 #include <cerrno>
20 #include <climits>
21 #include <cstdio>
22 #include <fcntl.h>
23 #include <sys/mman.h>
24 #include <unistd.h>
25 
26 #include "dictionary/utils/file_utils.h"
27 
28 namespace latinime {
29 
openBuffer(const char * const path,const int bufferOffset,const int bufferSize,const bool isUpdatable)30 /* static */ MmappedBuffer::MmappedBufferPtr MmappedBuffer::openBuffer(
31         const char *const path, const int bufferOffset, const int bufferSize,
32         const bool isUpdatable) {
33     const int mmapFd = open(path, O_RDONLY);
34     if (mmapFd < 0) {
35         AKLOGE("DICT: Can't open the source. path=%s errno=%d", path, errno);
36         return nullptr;
37     }
38     const int pagesize = sysconf(_SC_PAGESIZE);
39     const int offset = bufferOffset % pagesize;
40     int alignedOffset = bufferOffset - offset;
41     int alignedSize = bufferSize + offset;
42     const int protMode = isUpdatable ? PROT_READ | PROT_WRITE : PROT_READ;
43     void *const mmappedBuffer = mmap(0, alignedSize, protMode, MAP_PRIVATE, mmapFd,
44             alignedOffset);
45     if (mmappedBuffer == MAP_FAILED) {
46         AKLOGE("DICT: Can't mmap dictionary. errno=%d", errno);
47         close(mmapFd);
48         return nullptr;
49     }
50     uint8_t *const buffer = static_cast<uint8_t *>(mmappedBuffer) + offset;
51     if (!buffer) {
52         AKLOGE("DICT: buffer is null");
53         close(mmapFd);
54         return nullptr;
55     }
56     return MmappedBufferPtr(new MmappedBuffer(buffer, bufferSize, mmappedBuffer, alignedSize,
57             mmapFd, isUpdatable));
58 }
59 
openBuffer(const char * const path,const bool isUpdatable)60 /* static */ MmappedBuffer::MmappedBufferPtr MmappedBuffer::openBuffer(
61         const char *const path, const bool isUpdatable) {
62     const int fileSize = FileUtils::getFileSize(path);
63     if (fileSize == -1) {
64         return nullptr;
65     } else if (fileSize == 0) {
66         return MmappedBufferPtr(new MmappedBuffer(isUpdatable));
67     } else {
68         return openBuffer(path, 0 /* bufferOffset */, fileSize, isUpdatable);
69     }
70 }
71 
openBuffer(const char * const dirPath,const char * const fileName,const bool isUpdatable)72 /* static */ MmappedBuffer::MmappedBufferPtr MmappedBuffer::openBuffer(
73         const char *const dirPath, const char *const fileName, const bool isUpdatable) {
74     const int filePathBufferSize = PATH_MAX + 1 /* terminator */;
75     char filePath[filePathBufferSize];
76     const int filePathLength = snprintf(filePath, filePathBufferSize, "%s%s", dirPath,
77             fileName);
78     if (filePathLength >= filePathBufferSize) {
79         return nullptr;
80     }
81     return openBuffer(filePath, isUpdatable);
82 }
83 
~MmappedBuffer()84 MmappedBuffer::~MmappedBuffer() {
85     if (mAlignedSize == 0) {
86         return;
87     }
88     int ret = munmap(mMmappedBuffer, mAlignedSize);
89     if (ret != 0) {
90         AKLOGE("DICT: Failure in munmap. ret=%d errno=%d", ret, errno);
91     }
92     ret = close(mMmapFd);
93     if (ret != 0) {
94         AKLOGE("DICT: Failure in close. ret=%d errno=%d", ret, errno);
95     }
96 }
97 
98 } // namespace latinime
99