Make a special libc version for RTLD which doesn't use TLS as it will
[dragonfly.git] / lib / libc / gen / tls.c
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1/*-
2 * Copyright (c) 2004 Doug Rabson
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 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: src/lib/libc/gen/tls.c,v 1.7 2005/03/01 23:42:00 davidxu Exp $
7d6ff7ad 27 * $DragonFly: src/lib/libc/gen/tls.c,v 1.7 2005/04/28 18:29:54 joerg Exp $
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28 */
29
30/*
31 * Define stubs for TLS internals so that programs and libraries can
32 * link. These functions will be replaced by functional versions at
33 * runtime from ld-elf.so.1.
34 */
35
92df6c3e 36#include <sys/cdefs.h>
bc633d63 37#include <sys/tls.h>
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38
39#include <machine/tls.h>
40
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41#include <stdlib.h>
42#include <string.h>
43#include <elf.h>
44#include <assert.h>
92df6c3e 45
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46#include "libc_private.h"
47
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48__weak_reference(__libc_allocate_tls, _rtld_allocate_tls);
49__weak_reference(__libc_free_tls, _rtld_free_tls);
50#ifdef __i386__
51__weak_reference(___libc_tls_get_addr, ___tls_get_addr);
52#endif
53__weak_reference(__libc_tls_get_addr, __tls_get_addr);
54
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55struct tls_tcb *__libc_allocate_tls(struct tls_tcb *old_tcb);
56void __libc_free_tls(struct tls_tcb *tcb);
b00401f0 57
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58#if !defined(RTLD_STATIC_TLS_VARIANT_II)
59#error "Unsupported TLS layout"
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60#endif
61
62#ifndef PIC
63
64#define round(size, align) \
65 (((size) + (align) - 1) & ~((align) - 1))
66
67static size_t tls_static_space;
68static size_t tls_init_size;
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69static void *tls_init;
70#endif
71
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72#ifdef __i386__
73
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74/* GNU ABI */
75
76void *___libc_tls_get_addr(void *ti) __attribute__((__regparm__(1)));
b00401f0 77
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78__attribute__((__regparm__(1)))
79void *
92df6c3e 80___libc_tls_get_addr(void *ti __unused)
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81{
82 return (0);
83}
84
85#endif
86
92df6c3e 87void *__libc_tls_get_addr(void *ti);
bc633d63 88
b00401f0 89void *
92df6c3e 90__libc_tls_get_addr(void *ti __unused)
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91{
92 return (0);
93}
94
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95#ifndef PIC
96
b00401f0 97/*
bc633d63 98 * Free Static TLS
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99 */
100void
f20fd431 101__libc_free_tls(struct tls_tcb *tcb)
b00401f0 102{
bc633d63 103 size_t data_size;
b00401f0 104
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105 if (tcb->tcb_dtv)
106 free(tcb->tcb_dtv);
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107 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) &
108 ~RTLD_STATIC_TLS_ALIGN_MASK;
109 free((char *)tcb - data_size);
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110}
111
b00401f0 112/*
bc633d63 113 * Allocate Static TLS.
b00401f0 114 */
bc633d63 115struct tls_tcb *
f20fd431 116__libc_allocate_tls(struct tls_tcb *old_tcb)
b00401f0 117{
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118 size_t data_size;
119 struct tls_tcb *tcb;
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120 Elf_Addr *dtv;
121
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122 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) &
123 ~RTLD_STATIC_TLS_ALIGN_MASK;
f20fd431 124 tcb = malloc(data_size + sizeof(*tcb));
bc633d63 125 tcb = (struct tls_tcb *)((char *)tcb + data_size);
b00401f0 126 dtv = malloc(3 * sizeof(Elf_Addr));
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127
128#ifdef RTLD_TCB_HAS_SELF_POINTER
129 tcb->tcb_self = tcb;
130#endif
131 tcb->tcb_dtv = dtv;
132 tcb->tcb_pthread = NULL;
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133
134 dtv[0] = 1;
135 dtv[1] = 1;
bc633d63 136 dtv[2] = (Elf_Addr)((char *)tcb - tls_static_space);
b00401f0 137
bc633d63 138 if (old_tcb) {
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139 /*
140 * Copy the static TLS block over whole.
141 */
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142 memcpy((char *)tcb - tls_static_space,
143 (char *)old_tcb - tls_static_space,
144 tls_static_space);
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145
146 /*
147 * We assume that this block was the one we created with
148 * allocate_initial_tls().
149 */
f20fd431 150 _rtld_free_tls(old_tcb);
b00401f0 151 } else {
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152 memcpy((char *)tcb - tls_static_space,
153 tls_init, tls_init_size);
154 memset((char *)tcb - tls_static_space + tls_init_size,
155 0, tls_static_space - tls_init_size);
b00401f0 156 }
bc633d63 157 return (tcb);
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158}
159
b00401f0 160#else
92df6c3e 161
bc633d63 162struct tls_tcb *
f20fd431 163__libc_allocate_tls(struct tls_tcb *old_tls __unused)
92df6c3e 164{
b00401f0 165 return (0);
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166}
167
92df6c3e 168void
f20fd431 169__libc_free_tls(struct tls_tcb *tcb __unused)
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170{
171}
172
173#endif /* PIC */
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174
175extern char **environ;
176
177void
178_init_tls()
179{
180#ifndef PIC
181 Elf_Addr *sp;
182 Elf_Auxinfo *aux, *auxp;
183 Elf_Phdr *phdr;
184 size_t phent, phnum;
185 int i;
bc633d63 186 struct tls_tcb *tcb;
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187
188 sp = (Elf_Addr *) environ;
189 while (*sp++ != 0)
190 ;
191 aux = (Elf_Auxinfo *) sp;
192 phdr = 0;
193 phent = phnum = 0;
194 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
195 switch (auxp->a_type) {
196 case AT_PHDR:
197 phdr = auxp->a_un.a_ptr;
198 break;
199
200 case AT_PHENT:
201 phent = auxp->a_un.a_val;
202 break;
203
204 case AT_PHNUM:
205 phnum = auxp->a_un.a_val;
206 break;
207 }
208 }
209 if (phdr == 0 || phent != sizeof(Elf_Phdr) || phnum == 0)
210 return;
211
212 for (i = 0; (unsigned)i < phnum; i++) {
213 if (phdr[i].p_type == PT_TLS) {
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214 tls_static_space = round(phdr[i].p_memsz,
215 phdr[i].p_align);
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216 tls_init_size = phdr[i].p_filesz;
217 tls_init = (void*) phdr[i].p_vaddr;
218 }
219 }
220
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221 tcb = _rtld_allocate_tls(NULL);
222 tls_set_tcb(tcb);
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223#endif
224}