elf_utils.c revision 295407 
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: head/lib/libc/gen/elf_utils.c 295407 2016-02-08 19:24:13Z 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 "libc_private.h"
36
37int __elf_phdr_match_addr(struct dl_phdr_info *, void *);
38void __pthread_map_stacks_exec(void);
39
40int
41__elf_phdr_match_addr(struct dl_phdr_info *phdr_info, void *addr)
42{
43	const Elf_Phdr *ph;
44	int i;
45
46	for (i = 0; i < phdr_info->dlpi_phnum; i++) {
47		ph = &phdr_info->dlpi_phdr[i];
48		if (ph->p_type != PT_LOAD || (ph->p_flags & PF_X) == 0)
49			continue;
50		if (phdr_info->dlpi_addr + ph->p_vaddr <= (uintptr_t)addr &&
51		    (uintptr_t)addr + sizeof(addr) < phdr_info->dlpi_addr +
52		    ph->p_vaddr + ph->p_memsz)
53			break;
54	}
55	return (i != phdr_info->dlpi_phnum);
56}
57
58void
59__libc_map_stacks_exec(void)
60{
61	int mib[2];
62	struct rlimit rlim;
63	u_long usrstack;
64	size_t len;
65
66	mib[0] = CTL_KERN;
67	mib[1] = KERN_USRSTACK;
68	len = sizeof(usrstack);
69	if (sysctl(mib, sizeof(mib) / sizeof(mib[0]), &usrstack, &len, NULL, 0)
70	    == -1)
71		return;
72	if (getrlimit(RLIMIT_STACK, &rlim) == -1)
73		return;
74	mprotect((void *)(uintptr_t)(usrstack - rlim.rlim_cur),
75	    rlim.rlim_cur, _rtld_get_stack_prot());
76}
77
78#pragma weak __pthread_map_stacks_exec
79void
80__pthread_map_stacks_exec(void)
81{
82
83	((void (*)(void))__libc_interposing[INTERPOS_map_stacks_exec])();
84}
85