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tls.c revision 1.2 
      1 /*	$NetBSD: tls.c,v 1.2 2011/03/09 23:50:40 joerg Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2011 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Joerg Sonnenberger.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 __RCSID("$NetBSD: tls.c,v 1.2 2011/03/09 23:50:40 joerg Exp $");
     34 
     35 #include "namespace.h"
     36 
     37 #define	_rtld_tls_allocate	__libc_rtld_tls_allocate
     38 #define	_rtld_tls_free		__libc_rtld_tls_free
     39 
     40 #include <sys/tls.h>
     41 
     42 #if defined(__HAVE_TLS_VARIANT_I) || defined(__HAVE_TLS_VARIANT_II)
     43 
     44 #include <sys/param.h>
     45 #include <sys/mman.h>
     46 #include <link_elf.h>
     47 #include <lwp.h>
     48 #include <stddef.h>
     49 #include <stdlib.h>
     50 #include <string.h>
     51 #include <unistd.h>
     52 
     53 __dso_hidden void	__libc_static_tls_setup(void);
     54 
     55 static const void *tls_initaddr;
     56 static size_t tls_initsize;
     57 static size_t tls_size;
     58 static size_t tls_allocation;
     59 static void *initial_thread_tcb;
     60 
     61 __weak_alias(__tls_get_addr, 0)
     62 #ifdef __i386__
     63 __weak_alias(___tls_get_addr, 0)
     64 #endif
     65 
     66 __weak_alias(_rtld_tls_allocate, __libc_rtld_tls_allocate)
     67 
     68 struct tls_tcb *
     69 _rtld_tls_allocate(void)
     70 {
     71 	struct tls_tcb *tcb;
     72 	uint8_t *p;
     73 
     74 	if (initial_thread_tcb == NULL) {
     75 #ifdef __HAVE_TLS_VARIANT_II
     76 		tls_size = roundup2(tls_size, sizeof(void *));
     77 #endif
     78 		tls_allocation = tls_size + sizeof(*tcb);
     79 
     80 		initial_thread_tcb = p = mmap(NULL, tls_allocation,
     81 		    PROT_READ | PROT_WRITE, MAP_ANON, -1, 0);
     82 	} else {
     83 		p = calloc(1, tls_allocation);
     84 	}
     85 	if (p == NULL) {
     86 		static const char msg[] =  "TLS allocation failed, terminating\n";
     87 		write(STDERR_FILENO, msg, sizeof(msg));
     88 		_exit(127);
     89 	}
     90 #ifdef __HAVE_TLS_VARIANT_I
     91 	/* LINTED */
     92 	tcb = (struct tls_tcb *)p;
     93 	p += sizeof(struct tls_tcb);
     94 #else
     95 	/* LINTED tls_size is rounded above */
     96 	tcb = (struct tls_tcb *)(p + tls_size);
     97 	tcb->tcb_self = tcb;
     98 #endif
     99 	memcpy(p, tls_initaddr, tls_initsize);
    100 
    101 	return tcb;
    102 }
    103 
    104 __weak_alias(_rtld_tls_free, __libc_rtld_tls_free)
    105 
    106 void
    107 _rtld_tls_free(struct tls_tcb *tcb)
    108 {
    109 	uint8_t *p;
    110 
    111 #ifdef __HAVE_TLS_VARIANT_I
    112 	/* LINTED */
    113 	p = (uint8_t *)tcb;
    114 #else
    115 	/* LINTED */
    116 	p = (uint8_t *)tcb - tls_size;
    117 #endif
    118 	if (p == initial_thread_tcb)
    119 		munmap(p, tls_allocation);
    120 	else
    121 		free(p);
    122 }
    123 
    124 __weakref_visible int rtld_DYNAMIC __weak_reference(_DYNAMIC);
    125 
    126 static int
    127 __libc_static_tls_setup_cb(struct dl_phdr_info *data, size_t len, void *cookie)
    128 {
    129 	const Elf_Phdr *phdr = data->dlpi_phdr;
    130 	const Elf_Phdr *phlimit = data->dlpi_phdr + data->dlpi_phnum;
    131 
    132 	for (; phdr < phlimit; ++phdr) {
    133 		if (phdr->p_type != PT_TLS)
    134 			continue;
    135 		tls_initaddr = (void *)(phdr->p_vaddr + data->dlpi_addr);
    136 		tls_initsize = phdr->p_filesz;
    137 		tls_size = phdr->p_memsz;
    138 	}
    139 	return 0;
    140 }
    141 
    142 void
    143 __libc_static_tls_setup(void)
    144 {
    145 	struct tls_tcb *tcb;
    146 
    147 	if (&rtld_DYNAMIC != NULL)
    148 		return;
    149 
    150 	dl_iterate_phdr(__libc_static_tls_setup_cb, NULL);
    151 
    152 	tcb = _rtld_tls_allocate();
    153 	_lwp_setprivate(tcb);
    154 }
    155 
    156 #endif /* __HAVE_TLS_VARIANT_I || __HAVE_TLS_VARIANT_II */
    157