1/*
2 * Copyright (C) 2014 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#ifndef ART_RUNTIME_ELF_UTILS_H_
18#define ART_RUNTIME_ELF_UTILS_H_
19
20#include <sys/cdefs.h>
21
22// Explicitly include our own elf.h to avoid Linux and other dependencies.
23#include "./elf.h"
24
25#include "base/logging.h"
26
27namespace art {
28
29// Architecture dependent flags for the ELF header.
30#define EF_ARM_EABI_VER5 0x05000000
31#define EF_MIPS_ABI_O32 0x00001000
32#define EF_MIPS_ARCH_32R2 0x70000000
33#define EF_MIPS_ARCH_32R6 0x90000000
34#define EF_MIPS_ARCH_64R6 0xa0000000
35
36#define EI_ABIVERSION 8
37#define EM_ARM 40
38#define EF_MIPS_NOREORDER 1
39#define EF_MIPS_PIC 2
40#define EF_MIPS_CPIC 4
41#define STV_DEFAULT 0
42
43#define EM_AARCH64 183
44
45#define DT_BIND_NOW 24
46#define DT_INIT_ARRAY 25
47#define DT_FINI_ARRAY 26
48#define DT_INIT_ARRAYSZ 27
49#define DT_FINI_ARRAYSZ 28
50#define DT_RUNPATH 29
51#define DT_FLAGS 30
52
53/* MIPS dependent d_tag field for Elf32_Dyn.  */
54#define DT_MIPS_RLD_VERSION  0x70000001 /* Runtime Linker Interface ID */
55#define DT_MIPS_TIME_STAMP   0x70000002 /* Timestamp */
56#define DT_MIPS_ICHECKSUM    0x70000003 /* Cksum of ext. str. and com. sizes */
57#define DT_MIPS_IVERSION     0x70000004 /* Version string (string tbl index) */
58#define DT_MIPS_FLAGS        0x70000005 /* Flags */
59#define DT_MIPS_BASE_ADDRESS 0x70000006 /* Segment base address */
60#define DT_MIPS_CONFLICT     0x70000008 /* Adr of .conflict section */
61#define DT_MIPS_LIBLIST      0x70000009 /* Address of .liblist section */
62#define DT_MIPS_LOCAL_GOTNO  0x7000000a /* Number of local .GOT entries */
63#define DT_MIPS_CONFLICTNO   0x7000000b /* Number of .conflict entries */
64#define DT_MIPS_LIBLISTNO    0x70000010 /* Number of .liblist entries */
65#define DT_MIPS_SYMTABNO     0x70000011 /* Number of .dynsym entries */
66#define DT_MIPS_UNREFEXTNO   0x70000012 /* First external DYNSYM */
67#define DT_MIPS_GOTSYM       0x70000013 /* First GOT entry in .dynsym */
68#define DT_MIPS_HIPAGENO     0x70000014 /* Number of GOT page table entries */
69#define DT_MIPS_RLD_MAP      0x70000016 /* Address of debug map pointer */
70
71// Patching section type
72#define SHT_OAT_PATCH        SHT_LOUSER
73
74static inline void SetBindingAndType(Elf32_Sym* sym, unsigned char b, unsigned char t) {
75  sym->st_info = (b << 4) + (t & 0x0f);
76}
77
78static inline bool IsDynamicSectionPointer(Elf32_Word d_tag, Elf32_Word e_machine) {
79  switch (d_tag) {
80    // case 1: well known d_tag values that imply Elf32_Dyn.d_un contains an address in d_ptr
81    case DT_PLTGOT:
82    case DT_HASH:
83    case DT_STRTAB:
84    case DT_SYMTAB:
85    case DT_RELA:
86    case DT_INIT:
87    case DT_FINI:
88    case DT_REL:
89    case DT_DEBUG:
90    case DT_JMPREL: {
91      return true;
92    }
93    // d_val or ignored values
94    case DT_NULL:
95    case DT_NEEDED:
96    case DT_PLTRELSZ:
97    case DT_RELASZ:
98    case DT_RELAENT:
99    case DT_STRSZ:
100    case DT_SYMENT:
101    case DT_SONAME:
102    case DT_RPATH:
103    case DT_SYMBOLIC:
104    case DT_RELSZ:
105    case DT_RELENT:
106    case DT_PLTREL:
107    case DT_TEXTREL:
108    case DT_BIND_NOW:
109    case DT_INIT_ARRAYSZ:
110    case DT_FINI_ARRAYSZ:
111    case DT_RUNPATH:
112    case DT_FLAGS: {
113      return false;
114    }
115    // boundary values that should not be used
116    case DT_ENCODING:
117    case DT_LOOS:
118    case DT_HIOS:
119    case DT_LOPROC:
120    case DT_HIPROC: {
121      LOG(FATAL) << "Illegal d_tag value 0x" << std::hex << d_tag;
122      return false;
123    }
124    default: {
125      // case 2: "regular" DT_* ranges where even d_tag values imply an address in d_ptr
126      if ((DT_ENCODING  < d_tag && d_tag < DT_LOOS)
127          || (DT_LOOS   < d_tag && d_tag < DT_HIOS)
128          || (DT_LOPROC < d_tag && d_tag < DT_HIPROC)) {
129        // Special case for MIPS which breaks the regular rules between DT_LOPROC and DT_HIPROC
130        if (e_machine == EM_MIPS) {
131          switch (d_tag) {
132            case DT_MIPS_RLD_VERSION:
133            case DT_MIPS_TIME_STAMP:
134            case DT_MIPS_ICHECKSUM:
135            case DT_MIPS_IVERSION:
136            case DT_MIPS_FLAGS:
137            case DT_MIPS_LOCAL_GOTNO:
138            case DT_MIPS_CONFLICTNO:
139            case DT_MIPS_LIBLISTNO:
140            case DT_MIPS_SYMTABNO:
141            case DT_MIPS_UNREFEXTNO:
142            case DT_MIPS_GOTSYM:
143            case DT_MIPS_HIPAGENO: {
144              return false;
145            }
146            case DT_MIPS_BASE_ADDRESS:
147            case DT_MIPS_CONFLICT:
148            case DT_MIPS_LIBLIST:
149            case DT_MIPS_RLD_MAP: {
150              return true;
151            }
152            default: {
153              LOG(FATAL) << "Unknown MIPS d_tag value 0x" << std::hex << d_tag;
154              return false;
155            }
156          }
157        } else if ((d_tag % 2) == 0) {
158          return true;
159        } else {
160          return false;
161        }
162      } else {
163        LOG(FATAL) << "Unknown d_tag value 0x" << std::hex << d_tag;
164        return false;
165      }
166    }
167  }
168}
169
170}  // namespace art
171
172#endif  // ART_RUNTIME_ELF_UTILS_H_
173