#!/usr/bin/env python # # Copyright (c) 2012 Intel Corporation # # This program is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License version 2 as # published by the Free Software Foundation. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. # See the GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program; if not, write to the Free Software # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA # # DESCRIPTION # This script is called by the SDK installer script. It replaces the dynamic # loader path in all binaries and also fixes the SYSDIR paths/lengths and the # location of ld.so.cache in the dynamic loader binary # # AUTHORS # Laurentiu Palcu <laurentiu.palcu@intel.com> # import struct import sys import stat import os import re old_prefix = re.compile("##DEFAULT_INSTALL_DIR##") def get_arch(): f.seek(0) e_ident =f.read(16) ei_mag0,ei_mag1_3,ei_class = struct.unpack("<B3sB11x", e_ident) if (ei_mag0 != 0x7f and ei_mag1_3 != "ELF") or ei_class == 0: return 0 if ei_class == 1: return 32 elif ei_class == 2: return 64 def parse_elf_header(): global e_type, e_machine, e_version, e_entry, e_phoff, e_shoff, e_flags,\ e_ehsize, e_phentsize, e_phnum, e_shentsize, e_shnum, e_shstrndx f.seek(0) elf_header = f.read(64) if arch == 32: # 32bit hdr_struct = struct.Struct("<HHILLLIHHHHHH") hdr_size = 52 else: # 64bit hdr_struct = struct.Struct("<HHIQQQIHHHHHH") hdr_size = 64 e_type, e_machine, e_version, e_entry, e_phoff, e_shoff, e_flags,\ e_ehsize, e_phentsize, e_phnum, e_shentsize, e_shnum, e_shstrndx =\ hdr_struct.unpack(elf_header[16:hdr_size]) def change_interpreter(): if arch == 32: ph_struct = struct.Struct("<IIIIIIII") else: ph_struct = struct.Struct("<IIQQQQQQ") """ look for PT_INTERP section """ for i in range(0,e_phnum): f.seek(e_phoff + i * e_phentsize) ph_hdr = f.read(e_phentsize) if arch == 32: # 32bit p_type, p_offset, p_vaddr, p_paddr, p_filesz,\ p_memsz, p_flags, p_align = ph_struct.unpack(ph_hdr) else: # 64bit p_type, p_flags, p_offset, p_vaddr, p_paddr, \ p_filesz, p_memsz, p_align = ph_struct.unpack(ph_hdr) """ change interpreter """ if p_type == 3: # PT_INTERP section f.seek(p_offset) dl_path = new_dl_path + "\0" * (e_phentsize - len(new_dl_path)) f.write(new_dl_path) break def change_dl_sysdirs(): if arch == 32: sh_struct = struct.Struct("<IIIIIIIIII") else: sh_struct = struct.Struct("<IIQQQQIIQQ") """ read section string table """ f.seek(e_shoff + e_shstrndx * e_shentsize) sh_hdr = f.read(e_shentsize) if arch == 32: sh_offset, sh_size = struct.unpack("<16xII16x", sh_hdr) else: sh_offset, sh_size = struct.unpack("<24xQQ24x", sh_hdr) f.seek(sh_offset) sh_strtab = f.read(sh_size) sysdirs = sysdirs_len = "" """ change ld.so.cache path and default libs path for dynamic loader """ for i in range(0,e_shnum): f.seek(e_shoff + i * e_shentsize) sh_hdr = f.read(e_shentsize) sh_name, sh_type, sh_flags, sh_addr, sh_offset, sh_size, sh_link,\ sh_info, sh_addralign, sh_entsize = sh_struct.unpack(sh_hdr) name = sh_strtab[sh_name:sh_strtab.find("\0", sh_name)] """ look only into SHT_PROGBITS sections """ if sh_type == 1: f.seek(sh_offset) """ default library paths cannot be changed on the fly because """ """ the string lengths have to be changed too. """ if name == ".sysdirs": sysdirs = f.read(sh_size) sysdirs_off = sh_offset sysdirs_sect_size = sh_size elif name == ".sysdirslen": sysdirslen = f.read(sh_size) sysdirslen_off = sh_offset elif name == ".ldsocache": ldsocache_path = f.read(sh_size) new_ldsocache_path = old_prefix.sub(new_prefix, ldsocache_path) # pad with zeros new_ldsocache_path += "\0" * (sh_size - len(new_ldsocache_path)) # write it back f.seek(sh_offset) f.write(new_ldsocache_path) if sysdirs != "" and sysdirslen != "": paths = sysdirs.split("\0") sysdirs = "" sysdirslen = "" for path in paths: """ exit the loop when we encounter first empty string """ if path == "": break new_path = old_prefix.sub(new_prefix, path) sysdirs += new_path + "\0" if arch == 32: sysdirslen += struct.pack("<L", len(new_path)) else: sysdirslen += struct.pack("<Q", len(new_path)) """ pad with zeros """ sysdirs += "\0" * (sysdirs_sect_size - len(sysdirs)) """ write the sections back """ f.seek(sysdirs_off) f.write(sysdirs) f.seek(sysdirslen_off) f.write(sysdirslen) # MAIN if len(sys.argv) < 4: exit(1) new_prefix = sys.argv[1] new_dl_path = sys.argv[2] executables_list = sys.argv[3:] for e in executables_list: perms = os.stat(e)[stat.ST_MODE] if os.access(e, os.W_OK|os.R_OK): perms = None else: os.chmod(e, perms|stat.S_IRWXU) f = open(e, "r+b") arch = get_arch() if arch: parse_elf_header() change_interpreter() change_dl_sysdirs() """ change permissions back """ if perms: os.chmod(e, perms) f.close()