1 /*
2 * Copyright (C) 2017 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 "slicer/dex_format.h"
18
19 #include "slicer/common.h"
20
21 #include <sstream>
22 #include <cstdlib>
23 #include <zlib.h>
24
25 namespace dex {
26
27 // The expected format of the magic is dex\nXXX\0 where XXX are digits. We extract this value.
28 // Returns 0 if the version can not be parsed.
GetVersion(const void * magic)29 u4 Header::GetVersion(const void* magic) {
30 const char* version = reinterpret_cast<const char*>(magic) + 4;
31 return version[3] == '\0' ? strtol(version, nullptr, 10) : 0;
32 }
33
34 // Compute the DEX file checksum for a memory-mapped DEX file
ComputeChecksum(const Header * header)35 u4 ComputeChecksum(const Header* header) {
36 const u1* start = reinterpret_cast<const u1*>(header);
37
38 uLong adler = adler32(0L, Z_NULL, 0);
39 const int non_sum = sizeof(header->magic) + sizeof(header->checksum);
40
41 return static_cast<u4>(
42 adler32(adler, start + non_sum, header->file_size - non_sum));
43 }
44
45 // Returns the human-readable name for a primitive type
PrimitiveTypeName(char type_char)46 static const char* PrimitiveTypeName(char type_char) {
47 switch (type_char) {
48 case 'B': return "byte";
49 case 'C': return "char";
50 case 'D': return "double";
51 case 'F': return "float";
52 case 'I': return "int";
53 case 'J': return "long";
54 case 'S': return "short";
55 case 'V': return "void";
56 case 'Z': return "boolean";
57 }
58 SLICER_CHECK(!"unexpected type");
59 return nullptr;
60 }
61
62 // Converts a type descriptor to human-readable "dotted" form. For
63 // example, "Ljava/lang/String;" becomes "java.lang.String", and
64 // "[I" becomes "int[]".
DescriptorToDecl(const char * descriptor)65 std::string DescriptorToDecl(const char* descriptor) {
66 std::stringstream ss;
67
68 int array_dimensions = 0;
69 while (*descriptor == '[') {
70 ++array_dimensions;
71 ++descriptor;
72 }
73
74 if (*descriptor == 'L') {
75 for (++descriptor; *descriptor != ';'; ++descriptor) {
76 SLICER_CHECK_NE(*descriptor, '\0');
77 ss << (*descriptor == '/' ? '.' : *descriptor);
78 }
79 } else {
80 ss << PrimitiveTypeName(*descriptor);
81 }
82
83 SLICER_CHECK_EQ(descriptor[1], '\0');
84
85 // add the array brackets
86 for (int i = 0; i < array_dimensions; ++i) {
87 ss << "[]";
88 }
89
90 return ss.str();
91 }
92
93 // Converts a type descriptor to a single "shorty" char
94 // (ex. "LFoo;" and "[[I" become 'L', "I" stays 'I')
DescriptorToShorty(const char * descriptor)95 char DescriptorToShorty(const char* descriptor) {
96 // skip array dimensions
97 int array_dimensions = 0;
98 while (*descriptor == '[') {
99 ++array_dimensions;
100 ++descriptor;
101 }
102
103 char short_descriptor = *descriptor;
104 if (short_descriptor == 'L') {
105 // skip the full class name
106 for(; *descriptor && *descriptor != ';'; ++descriptor);
107 SLICER_CHECK_EQ(*descriptor, ';');
108 }
109
110 SLICER_CHECK_EQ(descriptor[1], '\0');
111 SLICER_CHECK(short_descriptor == 'L' || PrimitiveTypeName(short_descriptor) != nullptr);
112
113 return array_dimensions > 0 ? 'L' : short_descriptor;
114 }
115
116 } // namespace dex
117