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comparison: tools/reorder/elf_symbol_table.cpp
tools/reorder/elf_symbol_table.cpp
- changeset 0
- 6474c204b198
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| -1:000000000000 | 0:864b40e9d75a |
|---|---|
| 1 /* This Source Code Form is subject to the terms of the Mozilla Public | |
| 2 * License, v. 2.0. If a copy of the MPL was not distributed with this | |
| 3 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ | |
| 4 | |
| 5 #include <string> | |
| 6 #include <fstream> | |
| 7 #include <errno.h> | |
| 8 #include <fcntl.h> | |
| 9 #include <stdlib.h> | |
| 10 #include <stdio.h> | |
| 11 #include <unistd.h> | |
| 12 #include <sys/stat.h> | |
| 13 | |
| 14 #include "elf_symbol_table.h" | |
| 15 #include "elf_utils.h" | |
| 16 | |
| 17 int | |
| 18 elf_symbol_table::init(const char *name) | |
| 19 { | |
| 20 // Open the file readonly. | |
| 21 m_fd = open(name, O_RDONLY); | |
| 22 if (m_fd < 0) { | |
| 23 perror(name); | |
| 24 return m_fd; | |
| 25 } | |
| 26 | |
| 27 // Get its size. | |
| 28 struct stat statbuf; | |
| 29 if (fstat(m_fd, &statbuf) < 0) { | |
| 30 perror(name); | |
| 31 return -1; | |
| 32 } | |
| 33 | |
| 34 m_size = statbuf.st_size; | |
| 35 | |
| 36 // Memory map it. | |
| 37 m_mapping = mmap(0, m_size, PROT_READ, MAP_SHARED, m_fd, 0); | |
| 38 if (m_mapping == MAP_FAILED) { | |
| 39 perror(name); | |
| 40 return -1; | |
| 41 } | |
| 42 | |
| 43 // Make sure it's an ELF header. | |
| 44 const Elf32_Ehdr *ehdr = reinterpret_cast<const Elf32_Ehdr *>(m_mapping); | |
| 45 if (elf_verify_header(ehdr) < 0) | |
| 46 return -1; | |
| 47 | |
| 48 const char *mapping = reinterpret_cast<const char *>(m_mapping); | |
| 49 | |
| 50 // Find the section headers | |
| 51 const Elf32_Shdr *shdrs | |
| 52 = reinterpret_cast<const Elf32_Shdr *>(mapping + ehdr->e_shoff); | |
| 53 | |
| 54 // find the section header string table, .shstrtab | |
| 55 const Elf32_Shdr *shstrtabsh = shdrs + ehdr->e_shstrndx; | |
| 56 const char *shstrtab = mapping + shstrtabsh->sh_offset; | |
| 57 | |
| 58 // parse the sections we care about | |
| 59 int shndx = 0; | |
| 60 const Elf32_Shdr *shlimit = shdrs + ehdr->e_shnum; | |
| 61 for (const Elf32_Shdr *shdr = shdrs; shdr < shlimit; ++shdr, ++shndx) { | |
| 62 basic_string<char> name(shstrtab + shdr->sh_name); | |
| 63 if (name == ".symtab") { | |
| 64 m_symbols = reinterpret_cast<const Elf32_Sym *>(mapping + shdr->sh_offset); | |
| 65 m_nsymbols = shdr->sh_size / sizeof(Elf32_Sym); | |
| 66 } | |
| 67 else if (name == ".strtab") { | |
| 68 m_strtab = mapping + shdr->sh_offset; | |
| 69 } | |
| 70 else if (name == ".text") { | |
| 71 m_text_shndx = shndx; | |
| 72 } | |
| 73 } | |
| 74 | |
| 75 // Parse the symbol table | |
| 76 const Elf32_Sym *limit = m_symbols + m_nsymbols; | |
| 77 for (const Elf32_Sym *sym = m_symbols; sym < limit; ++sym) { | |
| 78 if (is_function(sym)) { | |
| 79 #ifdef DEBUG | |
| 80 hex(cout); | |
| 81 cout << sym->st_value << endl; | |
| 82 #endif | |
| 83 m_rsymtab.put(sym->st_value, sym->st_value + sym->st_size, sym); | |
| 84 } | |
| 85 } | |
| 86 | |
| 87 return 0; | |
| 88 } | |
| 89 | |
| 90 int | |
| 91 elf_symbol_table::finish() | |
| 92 { | |
| 93 if (m_mapping != MAP_FAILED) { | |
| 94 munmap(m_mapping, m_size); | |
| 95 m_mapping = MAP_FAILED; | |
| 96 } | |
| 97 | |
| 98 if (m_fd >= 0) { | |
| 99 close(m_fd); | |
| 100 m_fd = -1; | |
| 101 } | |
| 102 | |
| 103 return 0; | |
| 104 } | |
| 105 | |
| 106 const Elf32_Sym * | |
| 107 elf_symbol_table::lookup(unsigned int addr) const | |
| 108 { | |
| 109 rsymtab_t::const_iterator result = m_rsymtab.get(addr); | |
| 110 return result != m_rsymtab.end() ? reinterpret_cast<const Elf32_Sym *>(*result) : 0; | |
| 111 } | |
| 112 | |
| 113 const char * | |
| 114 elf_symbol_table::get_symbol_name(const Elf32_Sym *sym) const | |
| 115 { | |
| 116 return m_strtab + sym->st_name; | |
| 117 } |
