The Tor Browser / file diff

     1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/tools/reorder/elf_symbol_table.cpp	Wed Dec 31 06:09:35 2014 +0100
     1.3 @@ -0,0 +1,117 @@
     1.4 +/* This Source Code Form is subject to the terms of the Mozilla Public
     1.5 + * License, v. 2.0. If a copy of the MPL was not distributed with this
     1.6 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
     1.7 +
     1.8 +#include <string>
     1.9 +#include <fstream>
    1.10 +#include <errno.h>
    1.11 +#include <fcntl.h>
    1.12 +#include <stdlib.h>
    1.13 +#include <stdio.h>
    1.14 +#include <unistd.h>
    1.15 +#include <sys/stat.h>
    1.16 +
    1.17 +#include "elf_symbol_table.h"
    1.18 +#include "elf_utils.h"
    1.19 +
    1.20 +int
    1.21 +elf_symbol_table::init(const char *name)
    1.22 +{
    1.23 +    // Open the file readonly.
    1.24 +    m_fd = open(name, O_RDONLY);
    1.25 +    if (m_fd < 0) {
    1.26 +        perror(name);
    1.27 +        return m_fd;
    1.28 +    }
    1.29 +
    1.30 +    // Get its size.
    1.31 +    struct stat statbuf;
    1.32 +    if (fstat(m_fd, &statbuf) < 0) {
    1.33 +        perror(name);
    1.34 +        return -1;
    1.35 +    }
    1.36 +
    1.37 +    m_size = statbuf.st_size;
    1.38 +
    1.39 +    // Memory map it.
    1.40 +    m_mapping = mmap(0, m_size, PROT_READ, MAP_SHARED, m_fd, 0);
    1.41 +    if (m_mapping == MAP_FAILED) {
    1.42 +        perror(name);
    1.43 +        return -1;
    1.44 +    }
    1.45 +
    1.46 +    // Make sure it's an ELF header.
    1.47 +    const Elf32_Ehdr *ehdr = reinterpret_cast<const Elf32_Ehdr *>(m_mapping);
    1.48 +    if (elf_verify_header(ehdr) < 0)
    1.49 +        return -1;
    1.50 +
    1.51 +    const char *mapping = reinterpret_cast<const char *>(m_mapping);
    1.52 +
    1.53 +    // Find the section headers
    1.54 +    const Elf32_Shdr *shdrs
    1.55 +        = reinterpret_cast<const Elf32_Shdr *>(mapping + ehdr->e_shoff);
    1.56 +
    1.57 +    // find the section header string table, .shstrtab
    1.58 +    const Elf32_Shdr *shstrtabsh = shdrs + ehdr->e_shstrndx;
    1.59 +    const char *shstrtab = mapping + shstrtabsh->sh_offset;
    1.60 +
    1.61 +    // parse the sections we care about
    1.62 +    int shndx = 0;
    1.63 +    const Elf32_Shdr *shlimit = shdrs + ehdr->e_shnum;
    1.64 +    for (const Elf32_Shdr *shdr = shdrs; shdr < shlimit; ++shdr, ++shndx) {
    1.65 +        basic_string<char> name(shstrtab + shdr->sh_name);
    1.66 +        if (name == ".symtab") {
    1.67 +            m_symbols = reinterpret_cast<const Elf32_Sym *>(mapping + shdr->sh_offset);
    1.68 +            m_nsymbols = shdr->sh_size / sizeof(Elf32_Sym);
    1.69 +        }
    1.70 +        else if (name == ".strtab") {
    1.71 +            m_strtab = mapping + shdr->sh_offset;
    1.72 +        }
    1.73 +        else if (name == ".text") {
    1.74 +            m_text_shndx = shndx;
    1.75 +        }
    1.76 +    }
    1.77 +
    1.78 +    // Parse the symbol table
    1.79 +    const Elf32_Sym *limit = m_symbols + m_nsymbols;
    1.80 +    for (const Elf32_Sym *sym = m_symbols; sym < limit; ++sym) {
    1.81 +        if (is_function(sym)) {
    1.82 +#ifdef DEBUG
    1.83 +            hex(cout);
    1.84 +            cout << sym->st_value << endl;
    1.85 +#endif
    1.86 +            m_rsymtab.put(sym->st_value, sym->st_value + sym->st_size, sym);
    1.87 +        }
    1.88 +    }
    1.89 +
    1.90 +    return 0;
    1.91 +}
    1.92 +
    1.93 +int
    1.94 +elf_symbol_table::finish()
    1.95 +{
    1.96 +    if (m_mapping != MAP_FAILED) {
    1.97 +        munmap(m_mapping, m_size);
    1.98 +        m_mapping = MAP_FAILED;
    1.99 +    }
   1.100 +
   1.101 +    if (m_fd >= 0) {
   1.102 +        close(m_fd);
   1.103 +        m_fd = -1;
   1.104 +    }
   1.105 +
   1.106 +    return 0;
   1.107 +}
   1.108 +
   1.109 +const Elf32_Sym *
   1.110 +elf_symbol_table::lookup(unsigned int addr) const
   1.111 +{
   1.112 +    rsymtab_t::const_iterator result = m_rsymtab.get(addr);
   1.113 +    return result != m_rsymtab.end() ? reinterpret_cast<const Elf32_Sym *>(*result) : 0;
   1.114 +}
   1.115 +
   1.116 +const char *
   1.117 +elf_symbol_table::get_symbol_name(const Elf32_Sym *sym) const
   1.118 +{
   1.119 +    return m_strtab + sym->st_name;
   1.120 +}