Remove some unnecessary inclusions of <sys/cdefs.h> across the tree.
[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 $
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27 */
28
29/*
30 * Define stubs for TLS internals so that programs and libraries can
31 * link. These functions will be replaced by functional versions at
32 * runtime from ld-elf.so.1.
33 */
34
bc633d63 35#include <sys/tls.h>
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36
37#include <machine/tls.h>
38
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39#include <stdlib.h>
40#include <string.h>
41#include <elf.h>
42#include <assert.h>
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43#include <errno.h>
44#include <unistd.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);
a1eee96a 50__weak_reference(__libc_call_init, _rtld_call_init);
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51#ifdef __i386__
52__weak_reference(___libc_tls_get_addr, ___tls_get_addr);
53#endif
54__weak_reference(__libc_tls_get_addr, __tls_get_addr);
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55__weak_reference(__libc_tls_get_addr_tcb, __tls_get_addr_tcb);
56__weak_reference(_libc_init_tls, _init_tls);
92df6c3e 57
a1eee96a 58struct tls_tcb *__libc_allocate_tls(void);
f20fd431 59void __libc_free_tls(struct tls_tcb *tcb);
b00401f0 60
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61#if !defined(RTLD_STATIC_TLS_VARIANT_II)
62#error "Unsupported TLS layout"
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63#endif
64
65#ifndef PIC
66
67#define round(size, align) \
68 (((size) + (align) - 1) & ~((align) - 1))
69
70static size_t tls_static_space;
71static size_t tls_init_size;
b00401f0 72static void *tls_init;
a1eee96a 73static struct tls_tcb *initial_tcb;
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74#endif
75
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76#ifdef __i386__
77
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78/* GNU ABI */
79
80void *___libc_tls_get_addr(void *ti) __attribute__((__regparm__(1)));
b00401f0 81
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82__attribute__((__regparm__(1)))
83void *
92df6c3e 84___libc_tls_get_addr(void *ti __unused)
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85{
86 return (0);
87}
88
89#endif
90
92df6c3e 91void *__libc_tls_get_addr(void *ti);
a1eee96a 92void *__libc_tls_get_addr_tcb(struct tls_tcb *, void *);
bc633d63 93
b00401f0 94void *
92df6c3e 95__libc_tls_get_addr(void *ti __unused)
b00401f0 96{
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97 return (NULL);
98}
99
100void *
101__libc_tls_get_addr_tcb(struct tls_tcb *tcb __unused, void *got_ptr __unused)
102{
103 return (NULL);
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104}
105
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106#ifndef PIC
107
b00401f0 108/*
a1eee96a 109 * Free Static TLS, weakly bound to _rtld_free_tls()
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110 */
111void
f20fd431 112__libc_free_tls(struct tls_tcb *tcb)
b00401f0 113{
bc633d63 114 size_t data_size;
b00401f0 115
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116 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) &
117 ~RTLD_STATIC_TLS_ALIGN_MASK;
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118
119 if (tcb == initial_tcb) {
120 /* initial_tcb was allocated with sbrk(), cannot call free() */
121 } else {
122 free((char *)tcb - data_size);
123 }
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124}
125
b00401f0 126/*
a1eee96a 127 * Allocate Static TLS, weakly bound to _rtld_allocate_tls()
a378ce7d 128 *
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129 * NOTE! There is a chicken-and-egg problem here because no TLS exists
130 * on the first call into this function.
b00401f0 131 */
bc633d63 132struct tls_tcb *
a1eee96a 133__libc_allocate_tls(void)
b00401f0 134{
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135 size_t data_size;
136 struct tls_tcb *tcb;
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137 Elf_Addr *dtv;
138
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139 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) &
140 ~RTLD_STATIC_TLS_ALIGN_MASK;
a378ce7d 141
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142 /*
143 * Allocate space. malloc() may require a working TLS segment
144 * so we use sbrk() for main's TLS.
145 */
146 if (initial_tcb == NULL)
97c6bef2 147 tcb = sbrk(data_size + sizeof(*tcb) + 3 * sizeof(*dtv));
a378ce7d 148 else
97c6bef2 149 tcb = malloc(data_size + sizeof(*tcb) + 3 * sizeof(*dtv));
a1eee96a 150
bc633d63 151 tcb = (struct tls_tcb *)((char *)tcb + data_size);
a1eee96a 152 dtv = (Elf_Addr *)(tcb + 1);
9e2ee207 153
a1eee96a 154 memset(tcb, 0, sizeof(*tcb));
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155#ifdef RTLD_TCB_HAS_SELF_POINTER
156 tcb->tcb_self = tcb;
157#endif
158 tcb->tcb_dtv = dtv;
b00401f0 159
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160 /*
161 * Dummy-up the module array. A static binary has only one. This
162 * allows us to support the generic __tls_get_addr compiler ABI
163 * function. However, if there is no RTLD linked in, nothing in
164 * the program should ever call __tls_get_addr (and our version
165 * of it doesn't do anything).
166 */
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167 dtv[0] = 1;
168 dtv[1] = 1;
bc633d63 169 dtv[2] = (Elf_Addr)((char *)tcb - tls_static_space);
b00401f0 170
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171 memcpy((char *)tcb - tls_static_space,
172 tls_init, tls_init_size);
173 memset((char *)tcb - tls_static_space + tls_init_size,
174 0, tls_static_space - tls_init_size);
175
176 /*
177 * Activate the initial TCB
178 */
179 if (initial_tcb == NULL) {
180 initial_tcb = tcb;
181 tls_set_tcb(tcb);
b00401f0 182 }
a1eee96a 183 return (tcb);
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184}
185
b00401f0 186#else
92df6c3e 187
bc633d63 188struct tls_tcb *
a1eee96a 189__libc_allocate_tls(void)
92df6c3e 190{
a1eee96a 191 return (NULL);
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192}
193
92df6c3e 194void
f20fd431 195__libc_free_tls(struct tls_tcb *tcb __unused)
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196{
197}
198
199#endif /* PIC */
b00401f0 200
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201void
202__libc_call_init(void)
203{
204}
205
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206extern char **environ;
207
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208struct tls_tcb *
209_libc_init_tls(void)
b00401f0 210{
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211 struct tls_tcb *tcb;
212
b00401f0 213#ifndef PIC
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214 /*
215 * If this is a static binary there is no RTLD and so we have not
216 * yet calculated the static space requirement. Do so now.
217 */
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218 Elf_Addr *sp;
219 Elf_Auxinfo *aux, *auxp;
220 Elf_Phdr *phdr;
221 size_t phent, phnum;
222 int i;
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223
224 sp = (Elf_Addr *) environ;
225 while (*sp++ != 0)
226 ;
227 aux = (Elf_Auxinfo *) sp;
678e8cc6 228 phdr = NULL;
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229 phent = phnum = 0;
230 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
231 switch (auxp->a_type) {
232 case AT_PHDR:
233 phdr = auxp->a_un.a_ptr;
234 break;
235
236 case AT_PHENT:
237 phent = auxp->a_un.a_val;
238 break;
239
240 case AT_PHNUM:
241 phnum = auxp->a_un.a_val;
242 break;
243 }
244 }
678e8cc6 245 if (phdr == NULL || phent != sizeof(Elf_Phdr) || phnum == 0)
b0e25abd 246 return(NULL);
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247
248 for (i = 0; (unsigned)i < phnum; i++) {
249 if (phdr[i].p_type == PT_TLS) {
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250 tls_static_space = round(phdr[i].p_memsz,
251 phdr[i].p_align);
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252 tls_init_size = phdr[i].p_filesz;
253 tls_init = (void*) phdr[i].p_vaddr;
254 }
255 }
a1eee96a 256#endif
b00401f0 257
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258 /*
259 * Allocate the initial TLS segment. The TLS has not been set up
260 * yet for either the static or dynamic linked case (RTLD no longer
261 * sets up an initial TLS segment for us).
262 */
263 tcb = _libc_allocate_tls();
7d6ff7ad 264 tls_set_tcb(tcb);
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265 return(tcb);
266}
267
268/*
269 * Allocate a standard TLS. This function is called by libc and by
270 * thread libraries to create a new TCB with libc-related fields properly
271 * initialized (whereas _rtld_allocate_tls() is unable to completely set
272 * up the TCB).
273 *
274 * Note that this is different from __libc_allocate_tls which is the
275 * weakly bound symbol that handles the case where _rtld_allocate_tls
276 * does not exist.
277 */
278struct tls_tcb *
279_libc_allocate_tls(void)
280{
281 struct tls_tcb *tcb;
282
283 tcb = _rtld_allocate_tls();
284
285#if 0
286#if defined(__thread)
287 /* non-TLS libc */
288 tcb->tcb_errno_p = &errno;
289#elif defined(PIC)
290 /* TLS libc dynamically linked */
291 tcb->tcb_errno_p = __tls_get_addr_tcb(tcb, __get_errno_GOT_ptr());
292#else
293 /* TLS libc (threaded or unthreaded) */
294 tcb->tcb_errno_p = (void *)((char *)tcb + __get_errno_GS_offset());
b00401f0 295#endif
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296#endif
297 return(tcb);
b00401f0 298}
a1eee96a 299