#!/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
import errno
if sys.version < '3':
def b(x):
return x
else:
def b(x):
return x.encode(sys.getfilesystemencoding())
old_prefix = re.compile(b("##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_fmt = "<HHILLLIHHHHHH"
hdr_size = 52
else:
# 64bit
hdr_fmt = "<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 =\
struct.unpack(hdr_fmt, elf_header[16:hdr_size])
def change_interpreter(elf_file_name):
if arch == 32:
ph_fmt = "<IIIIIIII"
else:
ph_fmt = "<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 = struct.unpack(ph_fmt, ph_hdr)
else:
# 64bit
p_type, p_flags, p_offset, p_vaddr, p_paddr, \
p_filesz, p_memsz, p_align = struct.unpack(ph_fmt, ph_hdr)
""" change interpreter """
if p_type == 3:
# PT_INTERP section
f.seek(p_offset)
# External SDKs with mixed pre-compiled binaries should not get
# relocated so look for some variant of /lib
fname = f.read(11)
if fname.startswith(b("/lib/")) or fname.startswith(b("/lib64/")) or \
fname.startswith(b("/lib32/")) or fname.startswith(b("/usr/lib32/")) or \
fname.startswith(b("/usr/lib32/")) or fname.startswith(b("/usr/lib64/")):
break
if (len(new_dl_path) >= p_filesz):
print("ERROR: could not relocate %s, interp size = %i and %i is needed." \
% (elf_file_name, p_memsz, len(new_dl_path) + 1))
break
dl_path = new_dl_path + b("\0") * (p_filesz - len(new_dl_path))
f.seek(p_offset)
f.write(dl_path)
break
def change_dl_sysdirs():
if arch == 32:
sh_fmt = "<IIIIIIIIII"
else:
sh_fmt = "<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 = struct.unpack(sh_fmt, sh_hdr)
name = sh_strtab[sh_name:sh_strtab.find(b("\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 == b(".sysdirs"):
sysdirs = f.read(sh_size)
sysdirs_off = sh_offset
sysdirs_sect_size = sh_size
elif name == b(".sysdirslen"):
sysdirslen = f.read(sh_size)
sysdirslen_off = sh_offset
elif name == b(".ldsocache"):
ldsocache_path = f.read(sh_size)
new_ldsocache_path = old_prefix.sub(new_prefix, ldsocache_path)
# pad with zeros
new_ldsocache_path += b("\0") * (sh_size - len(new_ldsocache_path))
# write it back
f.seek(sh_offset)
f.write(new_ldsocache_path)
elif name == b(".gccrelocprefix"):
offset = 0
while (offset + 4096) <= sh_size:
path = f.read(4096)
new_path = old_prefix.sub(new_prefix, path)
# pad with zeros
new_path += b("\0") * (4096 - len(new_path))
#print "Changing %s to %s at %s" % (str(path), str(new_path), str(offset))
# write it back
f.seek(sh_offset + offset)
f.write(new_path)
offset = offset + 4096
if sysdirs != "" and sysdirslen != "":
paths = sysdirs.split(b("\0"))
sysdirs = b("")
sysdirslen = b("")
for path in paths:
""" exit the loop when we encounter first empty string """
if path == b(""):
break
new_path = old_prefix.sub(new_prefix, path)
sysdirs += new_path + b("\0")
if arch == 32:
sysdirslen += struct.pack("<L", len(new_path))
else:
sysdirslen += struct.pack("<Q", len(new_path))
""" pad with zeros """
sysdirs += b("\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:
sys.exit(-1)
# In python > 3, strings may also contain Unicode characters. So, convert
# them to bytes
if sys.version_info < (3,):
new_prefix = sys.argv[1]
new_dl_path = sys.argv[2]
else:
new_prefix = sys.argv[1].encode()
new_dl_path = sys.argv[2].encode()
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)
try:
f = open(e, "r+b")
except IOError:
exctype, ioex = sys.exc_info()[:2]
if ioex.errno == errno.ETXTBSY:
print("Could not open %s. File used by another process.\nPlease "\
"make sure you exit all processes that might use any SDK "\
"binaries." % e)
else:
print("Could not open %s: %s(%d)" % (e, ioex.strerror, ioex.errno))
sys.exit(-1)
# Save old size and do a size check at the end. Just a safety measure.
old_size = os.path.getsize(e)
if old_size >= 64:
arch = get_arch()
if arch:
parse_elf_header()
change_interpreter(e)
change_dl_sysdirs()
""" change permissions back """
if perms:
os.chmod(e, perms)
f.close()
if old_size != os.path.getsize(e):
print("New file size for %s is different. Looks like a relocation error!", e)
sys.exit(-1)
