elf_utils.c revision 346156 
1/*
2 * Copyright (c) 2010 Konstantin Belousov <kib@freebsd.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Neither the name of the author nor the names of any co-contributors
11 *    may be used to endorse or promote products derived from this software
12 *    without specific prior written permission.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: stable/11/lib/libc/gen/elf_utils.c 346156 2019-04-12 15:15:27Z kib $
27 */
28
29#include <sys/types.h>
30#include <sys/mman.h>
31#include <sys/resource.h>
32#include <sys/sysctl.h>
33#include <link.h>
34#include <stddef.h>
35#include <string.h>
36#include "libc_private.h"
37#include "static_tls.h"
38
39int __elf_phdr_match_addr(struct dl_phdr_info *, void *);
40void __pthread_map_stacks_exec(void);
41void __pthread_distribute_static_tls(size_t, void *, size_t, size_t);
42
43int
44__elf_phdr_match_addr(struct dl_phdr_info *phdr_info, void *addr)
45{
46	const Elf_Phdr *ph;
47	int i;
48
49	for (i = 0; i < phdr_info->dlpi_phnum; i++) {
50		ph = &phdr_info->dlpi_phdr[i];
51		if (ph->p_type != PT_LOAD || (ph->p_flags & PF_X) == 0)
52			continue;
53		if (phdr_info->dlpi_addr + ph->p_vaddr <= (uintptr_t)addr &&
54		    (uintptr_t)addr + sizeof(addr) < phdr_info->dlpi_addr +
55		    ph->p_vaddr + ph->p_memsz)
56			break;
57	}
58	return (i != phdr_info->dlpi_phnum);
59}
60
61void
62__libc_map_stacks_exec(void)
63{
64	int mib[2];
65	struct rlimit rlim;
66	u_long usrstack;
67	size_t len;
68
69	mib[0] = CTL_KERN;
70	mib[1] = KERN_USRSTACK;
71	len = sizeof(usrstack);
72	if (sysctl(mib, sizeof(mib) / sizeof(mib[0]), &usrstack, &len, NULL, 0)
73	    == -1)
74		return;
75	if (getrlimit(RLIMIT_STACK, &rlim) == -1)
76		return;
77	mprotect((void *)(uintptr_t)(usrstack - rlim.rlim_cur),
78	    rlim.rlim_cur, _rtld_get_stack_prot());
79}
80
81#pragma weak __pthread_map_stacks_exec
82void
83__pthread_map_stacks_exec(void)
84{
85
86	((void (*)(void))__libc_interposing[INTERPOS_map_stacks_exec])();
87}
88
89void
90__libc_distribute_static_tls(size_t offset, void *src, size_t len,
91    size_t total_len)
92{
93	uintptr_t tlsbase;
94
95	tlsbase = _libc_get_static_tls_base(offset);
96	memcpy((void *)tlsbase, src, len);
97	memset((char *)tlsbase + len, 0, total_len - len);
98}
99
100#pragma weak __pthread_distribute_static_tls
101void
102__pthread_distribute_static_tls(size_t offset, void *src, size_t len,
103    size_t total_len)
104{
105
106	((void (*)(size_t, void *, size_t, size_t))__libc_interposing[
107	    INTERPOS_distribute_static_tls])(offset, src, len, total_len);
108}
109