1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
|
/* Support for relocating static PIE.
Copyright (C) 2017-2025 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#if ENABLE_STATIC_PIE
/* Mark symbols hidden in static PIE for early self relocation to work. */
# pragma GCC visibility push(hidden)
#include <assert.h>
#include <unistd.h>
#include <ldsodefs.h>
#include <dl-machine.h>
#include <dl-debug.h>
#define RESOLVE_MAP(map, scope, sym, version, flags) map
#include "dynamic-link.h"
#include "get-dynamic-info.h"
/* Relocate static executable with PIE. */
void
_dl_relocate_static_pie (void)
{
struct link_map *main_map = _dl_get_dl_main_map ();
/* NB: elf_machine_load_address () returns the run-time load address
of static PIE. The l_addr field contains the difference between the
link-time load address in the ELF file and the run-time load address
in memory. We must subtract the link-time load address of static PIE,
which can be non-zero, when computing the l_addr field. Since static
PIE usually doesn't have PT_PHDR segment, use p_vaddr of the PT_LOAD
segment with offset == 0 as the load address of static PIE. */
ElfW(Addr) file_p_vaddr = 0;
const ElfW(Phdr) *ph, *phdr = GL(dl_phdr);
size_t phnum = GL(dl_phnum);
for (ph = phdr; ph < &phdr[phnum]; ++ph)
switch (ph->p_type)
{
case PT_LOAD:
/* Skip the empty PT_LOAD segment at offset 0. */
if (ph->p_filesz != 0 && ph->p_offset == 0)
file_p_vaddr = ph->p_vaddr;
break;
case PT_DYNAMIC:
main_map->l_ld_readonly = (ph->p_flags & PF_W) == 0;
break;
default:
break;
}
/* Figure out the run-time load address of static PIE. */
ElfW(Addr) l_addr = elf_machine_load_address ();
main_map->l_addr = l_addr - file_p_vaddr;
/* Read our own dynamic section and fill in the info array. */
main_map->l_ld = ((void *) l_addr + elf_machine_dynamic ());
elf_get_dynamic_info (main_map, false, true);
# ifdef ELF_MACHINE_BEFORE_RTLD_RELOC
ELF_MACHINE_BEFORE_RTLD_RELOC (main_map, main_map->l_info);
# endif
/* Relocate ourselves so we can do normal function calls and
data access using the global offset table. */
ELF_DYNAMIC_RELOCATE (main_map, NULL, 0, 0, 0);
main_map->l_relocated = 1;
/* Initialize _r_debug_extended. */
struct r_debug *r = _dl_debug_initialize (0, LM_ID_BASE);
r->r_state = RT_CONSISTENT;
/* Set up debugging before the debugger is notified for the first
time. */
elf_setup_debug_entry (main_map, r);
}
#endif
|
