1/*
2 * Copyright (C) 2006 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//
18// Shared file mapping class.
19//
20
21#define LOG_TAG "filemap"
22
23#include <utils/FileMap.h>
24#include <utils/Log.h>
25
26#if defined(__MINGW32__) && !defined(__USE_MINGW_ANSI_STDIO)
27# define PRId32 "I32d"
28# define PRIx32 "I32x"
29# define PRId64 "I64d"
30#else
31#include <inttypes.h>
32#endif
33#include <stdio.h>
34#include <stdlib.h>
35
36#if !defined(__MINGW32__)
37#include <sys/mman.h>
38#endif
39
40#include <string.h>
41#include <memory.h>
42#include <errno.h>
43#include <assert.h>
44
45using namespace android;
46
47/*static*/ long FileMap::mPageSize = -1;
48
49// Constructor.  Create an empty object.
50FileMap::FileMap(void)
51    : mFileName(NULL), mBasePtr(NULL), mBaseLength(0),
52      mDataPtr(NULL), mDataLength(0)
53{
54}
55
56// Destructor.
57FileMap::~FileMap(void)
58{
59    if (mFileName != NULL) {
60        free(mFileName);
61    }
62#if defined(__MINGW32__)
63    if (mBasePtr && UnmapViewOfFile(mBasePtr) == 0) {
64        ALOGD("UnmapViewOfFile(%p) failed, error = %" PRId32 "\n", mBasePtr,
65              GetLastError() );
66    }
67    if (mFileMapping != INVALID_HANDLE_VALUE) {
68        CloseHandle(mFileMapping);
69    }
70#else
71    if (mBasePtr && munmap(mBasePtr, mBaseLength) != 0) {
72        ALOGD("munmap(%p, %zu) failed\n", mBasePtr, mBaseLength);
73    }
74#endif
75}
76
77
78// Create a new mapping on an open file.
79//
80// Closing the file descriptor does not unmap the pages, so we don't
81// claim ownership of the fd.
82//
83// Returns "false" on failure.
84bool FileMap::create(const char* origFileName, int fd, off64_t offset, size_t length,
85        bool readOnly)
86{
87#if defined(__MINGW32__)
88    int     adjust;
89    off64_t adjOffset;
90    size_t  adjLength;
91
92    if (mPageSize == -1) {
93        SYSTEM_INFO  si;
94
95        GetSystemInfo( &si );
96        mPageSize = si.dwAllocationGranularity;
97    }
98
99    DWORD  protect = readOnly ? PAGE_READONLY : PAGE_READWRITE;
100
101    mFileHandle  = (HANDLE) _get_osfhandle(fd);
102    mFileMapping = CreateFileMapping( mFileHandle, NULL, protect, 0, 0, NULL);
103    if (mFileMapping == NULL) {
104        ALOGE("CreateFileMapping(%p, %" PRIx32 ") failed with error %" PRId32 "\n",
105              mFileHandle, protect, GetLastError() );
106        return false;
107    }
108
109    adjust    = offset % mPageSize;
110    adjOffset = offset - adjust;
111    adjLength = length + adjust;
112
113    mBasePtr = MapViewOfFile( mFileMapping,
114                              readOnly ? FILE_MAP_READ : FILE_MAP_ALL_ACCESS,
115                              0,
116                              (DWORD)(adjOffset),
117                              adjLength );
118    if (mBasePtr == NULL) {
119        ALOGE("MapViewOfFile(%" PRId64 ", %zu) failed with error %" PRId32 "\n",
120              adjOffset, adjLength, GetLastError() );
121        CloseHandle(mFileMapping);
122        mFileMapping = INVALID_HANDLE_VALUE;
123        return false;
124    }
125#else // !defined(__MINGW32__)
126    int     prot, flags, adjust;
127    off64_t adjOffset;
128    size_t  adjLength;
129
130    void* ptr;
131
132    assert(fd >= 0);
133    assert(offset >= 0);
134    assert(length > 0);
135
136    // init on first use
137    if (mPageSize == -1) {
138        mPageSize = sysconf(_SC_PAGESIZE);
139        if (mPageSize == -1) {
140            ALOGE("could not get _SC_PAGESIZE\n");
141            return false;
142        }
143    }
144
145    adjust = offset % mPageSize;
146    adjOffset = offset - adjust;
147    adjLength = length + adjust;
148
149    flags = MAP_SHARED;
150    prot = PROT_READ;
151    if (!readOnly)
152        prot |= PROT_WRITE;
153
154    ptr = mmap(NULL, adjLength, prot, flags, fd, adjOffset);
155    if (ptr == MAP_FAILED) {
156        ALOGE("mmap(%lld,%zu) failed: %s\n",
157            (long long)adjOffset, adjLength, strerror(errno));
158        return false;
159    }
160    mBasePtr = ptr;
161#endif // !defined(__MINGW32__)
162
163    mFileName = origFileName != NULL ? strdup(origFileName) : NULL;
164    mBaseLength = adjLength;
165    mDataOffset = offset;
166    mDataPtr = (char*) mBasePtr + adjust;
167    mDataLength = length;
168
169    assert(mBasePtr != NULL);
170
171    ALOGV("MAP: base %p/%zu data %p/%zu\n",
172        mBasePtr, mBaseLength, mDataPtr, mDataLength);
173
174    return true;
175}
176
177// Provide guidance to the system.
178#if !defined(_WIN32)
179int FileMap::advise(MapAdvice advice)
180{
181    int cc, sysAdvice;
182
183    switch (advice) {
184        case NORMAL:        sysAdvice = MADV_NORMAL;        break;
185        case RANDOM:        sysAdvice = MADV_RANDOM;        break;
186        case SEQUENTIAL:    sysAdvice = MADV_SEQUENTIAL;    break;
187        case WILLNEED:      sysAdvice = MADV_WILLNEED;      break;
188        case DONTNEED:      sysAdvice = MADV_DONTNEED;      break;
189        default:
190                            assert(false);
191                            return -1;
192    }
193
194    cc = madvise(mBasePtr, mBaseLength, sysAdvice);
195    if (cc != 0)
196        ALOGW("madvise(%d) failed: %s\n", sysAdvice, strerror(errno));
197    return cc;
198}
199
200#else
201int FileMap::advise(MapAdvice /* advice */)
202{
203    return -1;
204}
205#endif
206