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
31static inline RSExecRef wrap(ELFObject<32> *object) {
32  return reinterpret_cast<RSExecRef>(object);
33}
34
35static inline ELFObject<32> *unwrap(RSExecRef object) {
36  return reinterpret_cast<ELFObject<32> *>(object);
37}
38
39extern "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
56extern "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
69extern "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
78extern "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
100extern "C" void rsloaderDisposeExec(RSExecRef object) {
101  delete unwrap(object);
102}
103
104extern "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
127extern "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
147extern "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
158extern "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