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