auxv.c revision 331722 
1/*-
2 * Copyright 2010, 2012 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. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 *
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD: stable/11/lib/libc/gen/auxv.c 331722 2018-03-29 02:50:57Z eadler $");
29
30#include "namespace.h"
31#include <elf.h>
32#include <errno.h>
33#include <link.h>
34#include <pthread.h>
35#include <string.h>
36#include "un-namespace.h"
37#include "libc_private.h"
38
39extern char **environ;
40extern int _DYNAMIC;
41#pragma weak _DYNAMIC
42
43void *__elf_aux_vector;
44static pthread_once_t aux_vector_once = PTHREAD_ONCE_INIT;
45
46static void
47init_aux_vector_once(void)
48{
49	Elf_Addr *sp;
50
51	sp = (Elf_Addr *)environ;
52	while (*sp++ != 0)
53		;
54	__elf_aux_vector = (Elf_Auxinfo *)sp;
55}
56
57void
58__init_elf_aux_vector(void)
59{
60
61	if (&_DYNAMIC != NULL)
62		return;
63	_once(&aux_vector_once, init_aux_vector_once);
64}
65
66static pthread_once_t aux_once = PTHREAD_ONCE_INIT;
67static int pagesize, osreldate, canary_len, ncpus, pagesizes_len;
68static char *canary, *pagesizes;
69static void *timekeep;
70
71static void
72init_aux(void)
73{
74	Elf_Auxinfo *aux;
75
76	for (aux = __elf_aux_vector; aux->a_type != AT_NULL; aux++) {
77		switch (aux->a_type) {
78		case AT_CANARY:
79			canary = (char *)(aux->a_un.a_ptr);
80			break;
81
82		case AT_CANARYLEN:
83			canary_len = aux->a_un.a_val;
84			break;
85
86		case AT_PAGESIZES:
87			pagesizes = (char *)(aux->a_un.a_ptr);
88			break;
89
90		case AT_PAGESIZESLEN:
91			pagesizes_len = aux->a_un.a_val;
92			break;
93
94		case AT_PAGESZ:
95			pagesize = aux->a_un.a_val;
96			break;
97
98		case AT_OSRELDATE:
99			osreldate = aux->a_un.a_val;
100			break;
101
102		case AT_NCPUS:
103			ncpus = aux->a_un.a_val;
104			break;
105
106		case AT_TIMEKEEP:
107			timekeep = aux->a_un.a_ptr;
108			break;
109		}
110	}
111}
112
113int
114_elf_aux_info(int aux, void *buf, int buflen)
115{
116	int res;
117
118	__init_elf_aux_vector();
119	if (__elf_aux_vector == NULL)
120		return (ENOSYS);
121	_once(&aux_once, init_aux);
122
123	switch (aux) {
124	case AT_CANARY:
125		if (canary != NULL && canary_len >= buflen) {
126			memcpy(buf, canary, buflen);
127			memset(canary, 0, canary_len);
128			canary = NULL;
129			res = 0;
130		} else
131			res = ENOENT;
132		break;
133	case AT_PAGESIZES:
134		if (pagesizes != NULL && pagesizes_len >= buflen) {
135			memcpy(buf, pagesizes, buflen);
136			res = 0;
137		} else
138			res = ENOENT;
139		break;
140
141	case AT_PAGESZ:
142		if (buflen == sizeof(int)) {
143			if (pagesize != 0) {
144				*(int *)buf = pagesize;
145				res = 0;
146			} else
147				res = ENOENT;
148		} else
149			res = EINVAL;
150		break;
151	case AT_OSRELDATE:
152		if (buflen == sizeof(int)) {
153			if (osreldate != 0) {
154				*(int *)buf = osreldate;
155				res = 0;
156			} else
157				res = ENOENT;
158		} else
159			res = EINVAL;
160		break;
161	case AT_NCPUS:
162		if (buflen == sizeof(int)) {
163			if (ncpus != 0) {
164				*(int *)buf = ncpus;
165				res = 0;
166			} else
167				res = ENOENT;
168		} else
169			res = EINVAL;
170		break;
171	case AT_TIMEKEEP:
172		if (buflen == sizeof(void *)) {
173			if (timekeep != NULL) {
174				*(void **)buf = timekeep;
175				res = 0;
176			} else
177				res = ENOENT;
178		} else
179			res = EINVAL;
180		break;
181	default:
182		res = ENOENT;
183		break;
184	}
185	return (res);
186}
187