mirror of
https://github.com/mozilla/gecko-dev.git
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118 lines
3.0 KiB
C++
118 lines
3.0 KiB
C++
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include <string>
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#include <fstream>
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#include <errno.h>
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#include <fcntl.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <unistd.h>
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#include <sys/stat.h>
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#include "elf_symbol_table.h"
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#include "elf_utils.h"
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int
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elf_symbol_table::init(const char *name)
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{
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// Open the file readonly.
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m_fd = open(name, O_RDONLY);
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if (m_fd < 0) {
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perror(name);
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return m_fd;
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}
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// Get its size.
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struct stat statbuf;
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if (fstat(m_fd, &statbuf) < 0) {
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perror(name);
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return -1;
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}
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m_size = statbuf.st_size;
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// Memory map it.
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m_mapping = mmap(0, m_size, PROT_READ, MAP_SHARED, m_fd, 0);
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if (m_mapping == MAP_FAILED) {
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perror(name);
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return -1;
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}
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// Make sure it's an ELF header.
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const Elf32_Ehdr *ehdr = reinterpret_cast<const Elf32_Ehdr *>(m_mapping);
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if (elf_verify_header(ehdr) < 0)
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return -1;
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const char *mapping = reinterpret_cast<const char *>(m_mapping);
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// Find the section headers
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const Elf32_Shdr *shdrs
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= reinterpret_cast<const Elf32_Shdr *>(mapping + ehdr->e_shoff);
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// find the section header string table, .shstrtab
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const Elf32_Shdr *shstrtabsh = shdrs + ehdr->e_shstrndx;
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const char *shstrtab = mapping + shstrtabsh->sh_offset;
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// parse the sections we care about
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int shndx = 0;
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const Elf32_Shdr *shlimit = shdrs + ehdr->e_shnum;
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for (const Elf32_Shdr *shdr = shdrs; shdr < shlimit; ++shdr, ++shndx) {
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basic_string<char> name(shstrtab + shdr->sh_name);
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if (name == ".symtab") {
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m_symbols = reinterpret_cast<const Elf32_Sym *>(mapping + shdr->sh_offset);
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m_nsymbols = shdr->sh_size / sizeof(Elf32_Sym);
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}
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else if (name == ".strtab") {
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m_strtab = mapping + shdr->sh_offset;
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}
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else if (name == ".text") {
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m_text_shndx = shndx;
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}
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}
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// Parse the symbol table
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const Elf32_Sym *limit = m_symbols + m_nsymbols;
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for (const Elf32_Sym *sym = m_symbols; sym < limit; ++sym) {
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if (is_function(sym)) {
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#ifdef DEBUG
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hex(cout);
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cout << sym->st_value << endl;
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#endif
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m_rsymtab.put(sym->st_value, sym->st_value + sym->st_size, sym);
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}
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}
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return 0;
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}
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int
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elf_symbol_table::finish()
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{
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if (m_mapping != MAP_FAILED) {
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munmap(m_mapping, m_size);
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m_mapping = MAP_FAILED;
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}
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if (m_fd >= 0) {
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close(m_fd);
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m_fd = -1;
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}
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return 0;
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}
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const Elf32_Sym *
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elf_symbol_table::lookup(unsigned int addr) const
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{
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rsymtab_t::const_iterator result = m_rsymtab.get(addr);
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return result != m_rsymtab.end() ? reinterpret_cast<const Elf32_Sym *>(*result) : 0;
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}
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const char *
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elf_symbol_table::get_symbol_name(const Elf32_Sym *sym) const
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{
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return m_strtab + sym->st_name;
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}
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