1 /*
2 * Copyright 2011-2012, 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 "librsloader.h"
18
19 #include "ELFObject.h"
20 #include "ELFSectionSymTab.h"
21 #include "ELFSymbol.h"
22
23 #include "utils/serialize.h"
24
25 #define LOG_TAG "bcc"
26 #include "cutils/log.h"
27
28 #include <llvm/ADT/OwningPtr.h>
29 #include <llvm/Support/ELF.h>
30
wrap(ELFObject<32> * object)31 static inline RSExecRef wrap(ELFObject<32> *object) {
32 return reinterpret_cast<RSExecRef>(object);
33 }
34
unwrap(RSExecRef object)35 static inline ELFObject<32> *unwrap(RSExecRef object) {
36 return reinterpret_cast<ELFObject<32> *>(object);
37 }
38
rsloaderCreateExec(unsigned char const * buf,size_t buf_size,RSFindSymbolFn find_symbol,void * find_symbol_context)39 extern "C" RSExecRef rsloaderCreateExec(unsigned char const *buf,
40 size_t buf_size,
41 RSFindSymbolFn find_symbol,
42 void *find_symbol_context) {
43 RSExecRef object = rsloaderLoadExecutable(buf, buf_size);
44 if (!object) {
45 return NULL;
46 }
47
48 if (!rsloaderRelocateExecutable(object, find_symbol, find_symbol_context)) {
49 rsloaderDisposeExec(object);
50 return NULL;
51 }
52
53 return object;
54 }
55
rsloaderLoadExecutable(unsigned char const * buf,size_t buf_size)56 extern "C" RSExecRef rsloaderLoadExecutable(unsigned char const *buf,
57 size_t buf_size) {
58 ArchiveReaderLE AR(buf, buf_size);
59
60 llvm::OwningPtr<ELFObject<32> > object(ELFObject<32>::read(AR));
61 if (!object) {
62 ALOGE("Unable to load the ELF object.");
63 return NULL;
64 }
65
66 return wrap(object.take());
67 }
68
rsloaderRelocateExecutable(RSExecRef object_,RSFindSymbolFn find_symbol,void * find_symbol_context)69 extern "C" int rsloaderRelocateExecutable(RSExecRef object_,
70 RSFindSymbolFn find_symbol,
71 void *find_symbol_context) {
72 ELFObject<32>* object = unwrap(object_);
73
74 object->relocate(find_symbol, find_symbol_context);
75 return (object->getMissingSymbols() == 0);
76 }
77
rsloaderUpdateSectionHeaders(RSExecRef object_,unsigned char * buf)78 extern "C" void rsloaderUpdateSectionHeaders(RSExecRef object_,
79 unsigned char *buf) {
80 ELFObject<32> *object = unwrap(object_);
81
82 // Remap the section header addresses to match the loaded code
83 llvm::ELF::Elf32_Ehdr* header = reinterpret_cast<llvm::ELF::Elf32_Ehdr*>(buf);
84
85 llvm::ELF::Elf32_Shdr* shtab =
86 reinterpret_cast<llvm::ELF::Elf32_Shdr*>(buf + header->e_shoff);
87
88 for (int i = 0; i < header->e_shnum; i++) {
89 if (shtab[i].sh_flags & SHF_ALLOC) {
90 ELFSectionBits<32>* bits =
91 static_cast<ELFSectionBits<32>*>(object->getSectionByIndex(i));
92 if (bits) {
93 const unsigned char* addr = bits->getBuffer();
94 shtab[i].sh_addr = reinterpret_cast<llvm::ELF::Elf32_Addr>(addr);
95 }
96 }
97 }
98 }
99
rsloaderDisposeExec(RSExecRef object)100 extern "C" void rsloaderDisposeExec(RSExecRef object) {
101 delete unwrap(object);
102 }
103
rsloaderGetSymbolAddress(RSExecRef object_,char const * name)104 extern "C" void *rsloaderGetSymbolAddress(RSExecRef object_,
105 char const *name) {
106 ELFObject<32> *object = unwrap(object_);
107
108 ELFSectionSymTab<32> *symtab =
109 static_cast<ELFSectionSymTab<32> *>(object->getSectionByName(".symtab"));
110
111 if (!symtab) {
112 return NULL;
113 }
114
115 ELFSymbol<32> *symbol = symtab->getByName(name);
116
117 if (!symbol) {
118 ALOGV("Symbol not found: %s\n", name);
119 return NULL;
120 }
121
122 int machine = object->getHeader()->getMachine();
123
124 return symbol->getAddress(machine, false);
125 }
126
rsloaderGetSymbolSize(RSExecRef object_,char const * name)127 extern "C" size_t rsloaderGetSymbolSize(RSExecRef object_, char const *name) {
128 ELFObject<32> *object = unwrap(object_);
129
130 ELFSectionSymTab<32> *symtab =
131 static_cast<ELFSectionSymTab<32> *>(object->getSectionByName(".symtab"));
132
133 if (!symtab) {
134 return NULL;
135 }
136
137 ELFSymbol<32> *symbol = symtab->getByName(name);
138
139 if (!symbol) {
140 ALOGV("Symbol not found: %s\n", name);
141 return NULL;
142 }
143
144 return (size_t)symbol->getSize();
145 }
146
rsloaderGetFuncCount(RSExecRef object)147 extern "C" size_t rsloaderGetFuncCount(RSExecRef object) {
148 ELFSectionSymTab<32> *symtab = static_cast<ELFSectionSymTab<32> *>(
149 unwrap(object)->getSectionByName(".symtab"));
150
151 if (!symtab) {
152 return 0;
153 }
154
155 return symtab->getFuncCount();
156 }
157
rsloaderGetFuncNameList(RSExecRef object,size_t size,char const ** list)158 extern "C" void rsloaderGetFuncNameList(RSExecRef object,
159 size_t size,
160 char const **list) {
161 ELFSectionSymTab<32> *symtab = static_cast<ELFSectionSymTab<32> *>(
162 unwrap(object)->getSectionByName(".symtab"));
163
164 if (symtab) {
165 symtab->getFuncNameList(size, list);
166 }
167 }
168