1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
|
/*
* Copyright 2006 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "SysUtil.h"
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <algorithm>
#include <string>
#include <vector>
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/strings.h>
#include <android-base/unique_fd.h>
static bool sysMapFD(int fd, MemMapping* pMap) {
CHECK(pMap != nullptr);
struct stat sb;
if (fstat(fd, &sb) == -1) {
PLOG(ERROR) << "fstat(" << fd << ") failed";
return false;
}
void* memPtr = mmap(nullptr, sb.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
if (memPtr == MAP_FAILED) {
PLOG(ERROR) << "mmap(" << sb.st_size << ", R, PRIVATE, " << fd << ", 0) failed";
return false;
}
pMap->addr = static_cast<unsigned char*>(memPtr);
pMap->length = sb.st_size;
pMap->ranges.push_back({ memPtr, static_cast<size_t>(sb.st_size) });
return true;
}
// A "block map" which looks like this (from uncrypt/uncrypt.cpp):
//
// /dev/block/platform/msm_sdcc.1/by-name/userdata # block device
// 49652 4096 # file size in bytes, block size
// 3 # count of block ranges
// 1000 1008 # block range 0
// 2100 2102 # ... block range 1
// 30 33 # ... block range 2
//
// Each block range represents a half-open interval; the line "30 33"
// reprents the blocks [30, 31, 32].
static int sysMapBlockFile(const char* filename, MemMapping* pMap) {
CHECK(pMap != nullptr);
std::string content;
if (!android::base::ReadFileToString(filename, &content)) {
PLOG(ERROR) << "Failed to read " << filename;
return -1;
}
std::vector<std::string> lines = android::base::Split(android::base::Trim(content), "\n");
if (lines.size() < 4) {
LOG(ERROR) << "Block map file is too short: " << lines.size();
return -1;
}
size_t size;
unsigned int blksize;
if (sscanf(lines[1].c_str(), "%zu %u", &size, &blksize) != 2) {
LOG(ERROR) << "Failed to parse file size and block size: " << lines[1];
return -1;
}
size_t range_count;
if (sscanf(lines[2].c_str(), "%zu", &range_count) != 1) {
LOG(ERROR) << "Failed to parse block map header: " << lines[2];
return -1;
}
size_t blocks;
if (blksize != 0) {
blocks = ((size - 1) / blksize) + 1;
}
if (size == 0 || blksize == 0 || blocks > SIZE_MAX / blksize || range_count == 0 ||
lines.size() != 3 + range_count) {
LOG(ERROR) << "Invalid data in block map file: size " << size << ", blksize " << blksize
<< ", range_count " << range_count << ", lines " << lines.size();
return -1;
}
// Reserve enough contiguous address space for the whole file.
void* reserve = mmap64(nullptr, blocks * blksize, PROT_NONE, MAP_PRIVATE | MAP_ANON, -1, 0);
if (reserve == MAP_FAILED) {
PLOG(ERROR) << "failed to reserve address space";
return -1;
}
const std::string& block_dev = lines[0];
android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(block_dev.c_str(), O_RDONLY)));
if (fd == -1) {
PLOG(ERROR) << "failed to open block device " << block_dev;
munmap(reserve, blocks * blksize);
return -1;
}
pMap->ranges.resize(range_count);
unsigned char* next = static_cast<unsigned char*>(reserve);
size_t remaining_size = blocks * blksize;
bool success = true;
for (size_t i = 0; i < range_count; ++i) {
const std::string& line = lines[i + 3];
size_t start, end;
if (sscanf(line.c_str(), "%zu %zu\n", &start, &end) != 2) {
LOG(ERROR) << "failed to parse range " << i << " in block map: " << line;
success = false;
break;
}
size_t length = (end - start) * blksize;
if (end <= start || (end - start) > SIZE_MAX / blksize || length > remaining_size) {
LOG(ERROR) << "unexpected range in block map: " << start << " " << end;
success = false;
break;
}
void* addr = mmap64(next, length, PROT_READ, MAP_PRIVATE | MAP_FIXED, fd,
static_cast<off64_t>(start) * blksize);
if (addr == MAP_FAILED) {
PLOG(ERROR) << "failed to map block " << i;
success = false;
break;
}
pMap->ranges[i].addr = addr;
pMap->ranges[i].length = length;
next += length;
remaining_size -= length;
}
if (success && remaining_size != 0) {
LOG(ERROR) << "ranges in block map are invalid: remaining_size = " << remaining_size;
success = false;
}
if (!success) {
munmap(reserve, blocks * blksize);
return -1;
}
pMap->addr = static_cast<unsigned char*>(reserve);
pMap->length = size;
LOG(INFO) << "mmapped " << range_count << " ranges";
return 0;
}
int sysMapFile(const char* fn, MemMapping* pMap) {
if (fn == nullptr || pMap == nullptr) {
LOG(ERROR) << "Invalid argument(s)";
return -1;
}
*pMap = {};
if (fn[0] == '@') {
if (sysMapBlockFile(fn + 1, pMap) != 0) {
LOG(ERROR) << "Map of '" << fn << "' failed";
return -1;
}
} else {
// This is a regular file.
android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(fn, O_RDONLY)));
if (fd == -1) {
PLOG(ERROR) << "Unable to open '" << fn << "'";
return -1;
}
if (!sysMapFD(fd, pMap)) {
LOG(ERROR) << "Map of '" << fn << "' failed";
return -1;
}
}
return 0;
}
/*
* Release a memory mapping.
*/
void sysReleaseMap(MemMapping* pMap) {
std::for_each(pMap->ranges.cbegin(), pMap->ranges.cend(), [](const MappedRange& range) {
if (munmap(range.addr, range.length) == -1) {
PLOG(ERROR) << "munmap(" << range.addr << ", " << range.length << ") failed";
}
});
pMap->ranges.clear();
}
|
