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