librsloader.cpp revision ce2e754ed4b1aefe607bbbddd8ce0e6cba824e8f 
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    LOGE("Unable to load the ELF object.");
50    return NULL;
51  }
52
53  //object->print();
54  object->relocate(find_symbol, find_symbol_context);
55
56  return wrap(object.take());
57}
58
59extern "C" void rsloaderUpdateSectionHeaders(RSExecRef object_,
60                                             unsigned char *buf) {
61  ELFObject<32> *object = unwrap(object_);
62
63  // Remap the section header addresses to match the loaded code
64  llvm::ELF::Elf32_Ehdr* header = reinterpret_cast<llvm::ELF::Elf32_Ehdr*>(buf);
65
66  llvm::ELF::Elf32_Shdr* shtab =
67      reinterpret_cast<llvm::ELF::Elf32_Shdr*>(buf + header->e_shoff);
68
69  for (int i = 0; i < header->e_shnum; i++) {
70    if (shtab[i].sh_flags & SHF_ALLOC) {
71      ELFSectionBits<32>* bits =
72          static_cast<ELFSectionBits<32>*>(object->getSectionByIndex(i));
73      if (bits) {
74        const unsigned char* addr = bits->getBuffer();
75        shtab[i].sh_addr = reinterpret_cast<llvm::ELF::Elf32_Addr>(addr);
76      }
77    }
78  }
79}
80
81extern "C" void rsloaderDisposeExec(RSExecRef object) {
82  delete unwrap(object);
83}
84
85extern "C" void *rsloaderGetSymbolAddress(RSExecRef object_,
86                                          char const *name) {
87  ELFObject<32> *object = unwrap(object_);
88
89  ELFSectionSymTab<32> *symtab =
90    static_cast<ELFSectionSymTab<32> *>(object->getSectionByName(".symtab"));
91
92  if (!symtab) {
93    return NULL;
94  }
95
96  ELFSymbol<32> *symbol = symtab->getByName(name);
97
98  if (!symbol) {
99    LOGE("Symbol not found: %s\n", name);
100    return NULL;
101  }
102
103  return symbol->getAddress(false);
104}
105
106extern "C" size_t rsloaderGetSymbolSize(RSExecRef object_, char const *name) {
107  ELFObject<32> *object = unwrap(object_);
108
109  ELFSectionSymTab<32> *symtab =
110    static_cast<ELFSectionSymTab<32> *>(object->getSectionByName(".symtab"));
111
112  if (!symtab) {
113    return NULL;
114  }
115
116  ELFSymbol<32> *symbol = symtab->getByName(name);
117
118  if (!symbol) {
119    LOGE("Symbol not found: %s\n", name);
120    return NULL;
121  }
122
123  return (size_t)symbol->getSize();
124}
125
126extern "C" size_t rsloaderGetFuncCount(RSExecRef object) {
127  ELFSectionSymTab<32> *symtab = static_cast<ELFSectionSymTab<32> *>(
128    unwrap(object)->getSectionByName(".symtab"));
129
130  if (!symtab) {
131    return 0;
132  }
133
134  return symtab->getFuncCount();
135}
136
137extern "C" void rsloaderGetFuncNameList(RSExecRef object,
138                                        size_t size,
139                                        char const **list) {
140  ELFSectionSymTab<32> *symtab = static_cast<ELFSectionSymTab<32> *>(
141    unwrap(object)->getSectionByName(".symtab"));
142
143  if (symtab) {
144    symtab->getFuncNameList(size, list);
145  }
146}
147