xref: /freebsd/lib/libc/gen/elf_utils.c (revision 6ae1554a5d9b318f8ad53ccc39fa5a961403da73)
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  * $FreeBSD$
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 
36 int __elf_phdr_match_addr(struct dl_phdr_info *, void *);
37 void __pthread_map_stacks_exec(void);
38 
39 int
40 __elf_phdr_match_addr(struct dl_phdr_info *phdr_info, void *addr)
41 {
42 	const Elf_Phdr *ph;
43 	int i;
44 
45 	for (i = 0; i < phdr_info->dlpi_phnum; i++) {
46 		ph = &phdr_info->dlpi_phdr[i];
47 		if (ph->p_type != PT_LOAD || (ph->p_flags & PF_X) == 0)
48 			continue;
49 		if (phdr_info->dlpi_addr + ph->p_vaddr <= (uintptr_t)addr &&
50 		    (uintptr_t)addr + sizeof(addr) < phdr_info->dlpi_addr +
51 		    ph->p_vaddr + ph->p_memsz)
52 			break;
53 	}
54 	return (i != phdr_info->dlpi_phnum);
55 }
56 
57 #pragma weak __pthread_map_stacks_exec
58 void
59 __pthread_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