xref: /openbmc/openbmc/poky/scripts/relocate_sdk.py (revision 43a6b7c2a48b0cb1381af4d3192d22a12ead65f0) 
1#!/usr/bin/env python3
2#
3# Copyright (c) 2012 Intel Corporation
4#
5# SPDX-License-Identifier: GPL-2.0-only
6#
7# DESCRIPTION
8# This script is called by the SDK installer script. It replaces the dynamic
9# loader path in all binaries and also fixes the SYSDIR paths/lengths and the
10# location of ld.so.cache in the dynamic loader binary
11#
12# AUTHORS
13# Laurentiu Palcu <laurentiu.palcu@intel.com>
14#
15
16import struct
17import sys
18import stat
19import os
20import re
21import errno
22
23if sys.version < '3':
24    def b(x):
25        return x
26else:
27    def b(x):
28        return x.encode(sys.getfilesystemencoding())
29
30old_prefix = re.compile(b("##DEFAULT_INSTALL_DIR##"))
31
32def get_arch():
33    global endian_prefix
34    f.seek(0)
35    e_ident =f.read(16)
36    ei_mag0,ei_mag1_3,ei_class,ei_data,ei_version = struct.unpack("<B3sBBB9x", e_ident)
37
38    # ei_data = 1 for little-endian & 0 for big-endian
39    if ei_data == 1:
40        endian_prefix = '<'
41    else:
42        endian_prefix = '>'
43
44    if (ei_mag0 != 0x7f and ei_mag1_3 != "ELF") or ei_class == 0:
45        return 0
46
47    if ei_class == 1:
48        return 32
49    elif ei_class == 2:
50        return 64
51
52def get_dl_arch(dl_path):
53    try:
54        with open(dl_path, "r+b") as f:
55            e_ident =f.read(16)
56    except IOError:
57        exctype, ioex = sys.exc_info()[:2]
58        if ioex.errno == errno.ETXTBSY:
59            print("Could not open %s. File used by another process.\nPlease "\
60                  "make sure you exit all processes that might use any SDK "\
61                  "binaries." % e)
62        else:
63            print("Could not open %s: %s(%d)" % (e, ioex.strerror, ioex.errno))
64        sys.exit(-1)
65
66    ei_mag0,ei_mag1_3,ei_class,ei_data,ei_version = struct.unpack("<B3sBBB9x", e_ident)
67
68    if (ei_mag0 != 0x7f and ei_mag1_3 != "ELF") or ei_class == 0:
69        print("ERROR: unknow %s" % dl_path)
70        sys.exit(-1)
71
72    if ei_class == 1:
73        arch = 32
74    elif ei_class == 2:
75        arch = 64
76
77    return arch
78
79
80def parse_elf_header():
81    global e_type, e_machine, e_version, e_entry, e_phoff, e_shoff, e_flags,\
82           e_ehsize, e_phentsize, e_phnum, e_shentsize, e_shnum, e_shstrndx
83
84    f.seek(0)
85    elf_header = f.read(64)
86
87    if arch == 32:
88        # 32bit
89        hdr_fmt = endian_prefix + "HHILLLIHHHHHH"
90        hdr_size = 52
91    else:
92        # 64bit
93        hdr_fmt = endian_prefix + "HHIQQQIHHHHHH"
94        hdr_size = 64
95
96    e_type, e_machine, e_version, e_entry, e_phoff, e_shoff, e_flags,\
97    e_ehsize, e_phentsize, e_phnum, e_shentsize, e_shnum, e_shstrndx =\
98        struct.unpack(hdr_fmt, elf_header[16:hdr_size])
99
100def change_interpreter(elf_file_name):
101    if arch == 32:
102        ph_fmt = endian_prefix + "IIIIIIII"
103    else:
104        ph_fmt = endian_prefix + "IIQQQQQQ"
105
106    """ look for PT_INTERP section """
107    for i in range(0,e_phnum):
108        f.seek(e_phoff + i * e_phentsize)
109        ph_hdr = f.read(e_phentsize)
110        if arch == 32:
111            # 32bit
112            p_type, p_offset, p_vaddr, p_paddr, p_filesz,\
113                p_memsz, p_flags, p_align = struct.unpack(ph_fmt, ph_hdr)
114        else:
115            # 64bit
116            p_type, p_flags, p_offset, p_vaddr, p_paddr, \
117            p_filesz, p_memsz, p_align = struct.unpack(ph_fmt, ph_hdr)
118
119        """ change interpreter """
120        if p_type == 3:
121            # PT_INTERP section
122            f.seek(p_offset)
123            # External SDKs with mixed pre-compiled binaries should not get
124            # relocated so look for some variant of /lib
125            fname = f.read(11)
126            if fname.startswith(b("/lib/")) or fname.startswith(b("/lib64/")) or \
127               fname.startswith(b("/lib32/")) or fname.startswith(b("/usr/lib32/")) or \
128               fname.startswith(b("/usr/lib32/")) or fname.startswith(b("/usr/lib64/")):
129                break
130            if p_filesz == 0:
131                break
132            if (len(new_dl_path) >= p_filesz):
133                print("ERROR: could not relocate %s, interp size = %i and %i is needed." \
134                    % (elf_file_name, p_memsz, len(new_dl_path) + 1))
135                return False
136            dl_path = new_dl_path + b("\0") * (p_filesz - len(new_dl_path))
137            f.seek(p_offset)
138            f.write(dl_path)
139            break
140    return True
141
142def change_dl_sysdirs(elf_file_name):
143    if arch == 32:
144        sh_fmt = endian_prefix + "IIIIIIIIII"
145    else:
146        sh_fmt = endian_prefix + "IIQQQQIIQQ"
147
148    """ read section string table """
149    f.seek(e_shoff + e_shstrndx * e_shentsize)
150    sh_hdr = f.read(e_shentsize)
151    if arch == 32:
152        sh_offset, sh_size = struct.unpack(endian_prefix + "16xII16x", sh_hdr)
153    else:
154        sh_offset, sh_size = struct.unpack(endian_prefix + "24xQQ24x", sh_hdr)
155
156    f.seek(sh_offset)
157    sh_strtab = f.read(sh_size)
158
159    sysdirs = sysdirs_len = ""
160
161    """ change ld.so.cache path and default libs path for dynamic loader """
162    for i in range(0,e_shnum):
163        f.seek(e_shoff + i * e_shentsize)
164        sh_hdr = f.read(e_shentsize)
165
166        sh_name, sh_type, sh_flags, sh_addr, sh_offset, sh_size, sh_link,\
167            sh_info, sh_addralign, sh_entsize = struct.unpack(sh_fmt, sh_hdr)
168
169        name = sh_strtab[sh_name:sh_strtab.find(b("\0"), sh_name)]
170
171        """ look only into SHT_PROGBITS sections """
172        if sh_type == 1:
173            f.seek(sh_offset)
174            """ default library paths cannot be changed on the fly because  """
175            """ the string lengths have to be changed too.                  """
176            if name == b(".sysdirs"):
177                sysdirs = f.read(sh_size)
178                sysdirs_off = sh_offset
179                sysdirs_sect_size = sh_size
180            elif name == b(".sysdirslen"):
181                sysdirslen = f.read(sh_size)
182                sysdirslen_off = sh_offset
183            elif name == b(".ldsocache"):
184                ldsocache_path = f.read(sh_size)
185                new_ldsocache_path = old_prefix.sub(new_prefix, ldsocache_path)
186                new_ldsocache_path = new_ldsocache_path.rstrip(b("\0"))
187                if (len(new_ldsocache_path) >= sh_size):
188                    print("ERROR: could not relocate %s, .ldsocache section size = %i and %i is needed." \
189                    % (elf_file_name, sh_size, len(new_ldsocache_path)))
190                    sys.exit(-1)
191                # pad with zeros
192                new_ldsocache_path += b("\0") * (sh_size - len(new_ldsocache_path))
193                # write it back
194                f.seek(sh_offset)
195                f.write(new_ldsocache_path)
196            elif name == b(".gccrelocprefix"):
197                offset = 0
198                while (offset + 4096) <= sh_size:
199                    path = f.read(4096)
200                    new_path = old_prefix.sub(new_prefix, path)
201                    new_path = new_path.rstrip(b("\0"))
202                    if (len(new_path) >= 4096):
203                        print("ERROR: could not relocate %s, max path size = 4096 and %i is needed." \
204                        % (elf_file_name, len(new_path)))
205                        sys.exit(-1)
206                    # pad with zeros
207                    new_path += b("\0") * (4096 - len(new_path))
208                    #print "Changing %s to %s at %s" % (str(path), str(new_path), str(offset))
209                    # write it back
210                    f.seek(sh_offset + offset)
211                    f.write(new_path)
212                    offset = offset + 4096
213    if sysdirs != "" and sysdirslen != "":
214        paths = sysdirs.split(b("\0"))
215        sysdirs = b("")
216        sysdirslen = b("")
217        for path in paths:
218            """ exit the loop when we encounter first empty string """
219            if path == b(""):
220                break
221
222            new_path = old_prefix.sub(new_prefix, path)
223            sysdirs += new_path + b("\0")
224
225            if arch == 32:
226                sysdirslen += struct.pack("<L", len(new_path))
227            else:
228                sysdirslen += struct.pack("<Q", len(new_path))
229
230        """ pad with zeros """
231        sysdirs += b("\0") * (sysdirs_sect_size - len(sysdirs))
232
233        """ write the sections back """
234        f.seek(sysdirs_off)
235        f.write(sysdirs)
236        f.seek(sysdirslen_off)
237        f.write(sysdirslen)
238
239# MAIN
240if len(sys.argv) < 4:
241    sys.exit(-1)
242
243# In python > 3, strings may also contain Unicode characters. So, convert
244# them to bytes
245if sys.version_info < (3,):
246    new_prefix = sys.argv[1]
247    new_dl_path = sys.argv[2]
248else:
249    new_prefix = sys.argv[1].encode()
250    new_dl_path = sys.argv[2].encode()
251
252executables_list = sys.argv[3:]
253
254dl_arch = get_dl_arch(new_dl_path)
255
256errors = False
257for e in executables_list:
258    perms = os.stat(e)[stat.ST_MODE]
259    if os.access(e, os.W_OK|os.R_OK):
260        perms = None
261    else:
262        os.chmod(e, perms|stat.S_IRWXU)
263
264    try:
265        f = open(e, "r+b")
266    except IOError:
267        exctype, ioex = sys.exc_info()[:2]
268        if ioex.errno == errno.ETXTBSY:
269            print("Could not open %s. File used by another process.\nPlease "\
270                  "make sure you exit all processes that might use any SDK "\
271                  "binaries." % e)
272        else:
273            print("Could not open %s: %s(%d)" % (e, ioex.strerror, ioex.errno))
274        sys.exit(-1)
275
276    # Save old size and do a size check at the end. Just a safety measure.
277    old_size = os.path.getsize(e)
278    if old_size >= 64:
279        arch = get_arch()
280        if arch and arch == dl_arch:
281            parse_elf_header()
282            if not change_interpreter(e):
283                errors = True
284            change_dl_sysdirs(e)
285
286    """ change permissions back """
287    if perms:
288        os.chmod(e, perms)
289
290    f.close()
291
292    if old_size != os.path.getsize(e):
293        print("New file size for %s is different. Looks like a relocation error!", e)
294        sys.exit(-1)
295
296if errors:
297    print("Relocation of one or more executables failed.")
298    sys.exit(-1)
299