librsloader.cpp revision 141f4435692cc53db032525e1cc602c3b417c42e 
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
40rsloaderCreateExec(unsigned char const *buf,
41                   size_t buf_size,
42                   void *(*find_symbol)(void *, char const *),
43                   void *find_symbol_context) {
44
45  ArchiveReaderLE AR(buf, buf_size);
46
47  llvm::OwningPtr<ELFObject<32> > object(ELFObject<32>::read(AR));
48  if (!object) {
49    ALOGE("Unable to load the ELF object.");
50    return NULL;
51  }
52
53  //object->print();
54  object->relocate(find_symbol, find_symbol_context);
55  if (object->getMissingSymbols()) {
56    return NULL;
57  }
58
59  return wrap(object.take());
60}
61
62extern "C" void rsloaderUpdateSectionHeaders(RSExecRef object_,
63                                             unsigned char *buf) {
64  ELFObject<32> *object = unwrap(object_);
65
66  // Remap the section header addresses to match the loaded code
67  llvm::ELF::Elf32_Ehdr* header = reinterpret_cast<llvm::ELF::Elf32_Ehdr*>(buf);
68
69  llvm::ELF::Elf32_Shdr* shtab =
70      reinterpret_cast<llvm::ELF::Elf32_Shdr*>(buf + header->e_shoff);
71
72  for (int i = 0; i < header->e_shnum; i++) {
73    if (shtab[i].sh_flags & SHF_ALLOC) {
74      ELFSectionBits<32>* bits =
75          static_cast<ELFSectionBits<32>*>(object->getSectionByIndex(i));
76      if (bits) {
77        const unsigned char* addr = bits->getBuffer();
78        shtab[i].sh_addr = reinterpret_cast<llvm::ELF::Elf32_Addr>(addr);
79      }
80    }
81  }
82}
83
84extern "C" void rsloaderDisposeExec(RSExecRef object) {
85  delete unwrap(object);
86}
87
88extern "C" void *rsloaderGetSymbolAddress(RSExecRef object_,
89                                          char const *name) {
90  ELFObject<32> *object = unwrap(object_);
91
92  ELFSectionSymTab<32> *symtab =
93    static_cast<ELFSectionSymTab<32> *>(object->getSectionByName(".symtab"));
94
95  if (!symtab) {
96    return NULL;
97  }
98
99  ELFSymbol<32> *symbol = symtab->getByName(name);
100
101  if (!symbol) {
102    ALOGV("Symbol not found: %s\n", name);
103    return NULL;
104  }
105
106  int machine = object->getHeader()->getMachine();
107
108  return symbol->getAddress(machine, false);
109}
110
111extern "C" size_t rsloaderGetSymbolSize(RSExecRef object_, char const *name) {
112  ELFObject<32> *object = unwrap(object_);
113
114  ELFSectionSymTab<32> *symtab =
115    static_cast<ELFSectionSymTab<32> *>(object->getSectionByName(".symtab"));
116
117  if (!symtab) {
118    return NULL;
119  }
120
121  ELFSymbol<32> *symbol = symtab->getByName(name);
122
123  if (!symbol) {
124    ALOGV("Symbol not found: %s\n", name);
125    return NULL;
126  }
127
128  return (size_t)symbol->getSize();
129}
130
131extern "C" size_t rsloaderGetFuncCount(RSExecRef object) {
132  ELFSectionSymTab<32> *symtab = static_cast<ELFSectionSymTab<32> *>(
133    unwrap(object)->getSectionByName(".symtab"));
134
135  if (!symtab) {
136    return 0;
137  }
138
139  return symtab->getFuncCount();
140}
141
142extern "C" void rsloaderGetFuncNameList(RSExecRef object,
143                                        size_t size,
144                                        char const **list) {
145  ELFSectionSymTab<32> *symtab = static_cast<ELFSectionSymTab<32> *>(
146    unwrap(object)->getSectionByName(".symtab"));
147
148  if (symtab) {
149    symtab->getFuncNameList(size, list);
150  }
151}
152