1 /* $NetBSD: tls.c,v 1.9 2018/07/13 19:50:21 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 1.9 2018/07/13 19:50:21 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 <stdbool.h> 49 #include <stddef.h> 50 #include <stdlib.h> 51 #include <string.h> 52 #include <unistd.h> 53 54 __dso_hidden void __libc_static_tls_setup(void); 55 56 static bool is_dynamic; 57 static const void *tls_initaddr; 58 static size_t tls_initsize; 59 static size_t tls_size; 60 static size_t tls_allocation; 61 static void *initial_thread_tcb; 62 63 void * __libc_tls_get_addr(void); 64 65 __weak_alias(__tls_get_addr, __libc_tls_get_addr) 66 #ifdef __i386__ 67 __weak_alias(___tls_get_addr, __libc_tls_get_addr) 68 #endif 69 70 void * 71 __libc_tls_get_addr(void) 72 { 73 74 abort(); 75 /* NOTREACHED */ 76 } 77 78 __weak_alias(_rtld_tls_allocate, __libc_rtld_tls_allocate) 79 80 struct tls_tcb * 81 _rtld_tls_allocate(void) 82 { 83 struct tls_tcb *tcb; 84 uint8_t *p; 85 86 if (initial_thread_tcb == NULL) { 87 #ifdef __HAVE_TLS_VARIANT_II 88 tls_size = roundup2(tls_size, sizeof(void *)); 89 #endif 90 tls_allocation = tls_size + sizeof(*tcb); 91 92 initial_thread_tcb = p = mmap(NULL, tls_allocation, 93 PROT_READ | PROT_WRITE, MAP_ANON, -1, 0); 94 } else { 95 p = calloc(1, tls_allocation); 96 } 97 if (p == NULL) { 98 static const char msg[] = "TLS allocation failed, terminating\n"; 99 write(STDERR_FILENO, msg, sizeof(msg)); 100 _exit(127); 101 } 102 #ifdef __HAVE_TLS_VARIANT_I 103 /* LINTED */ 104 tcb = (struct tls_tcb *)p; 105 p += sizeof(struct tls_tcb); 106 #else 107 /* LINTED tls_size is rounded above */ 108 tcb = (struct tls_tcb *)(p + tls_size); 109 tcb->tcb_self = tcb; 110 #endif 111 memcpy(p, tls_initaddr, tls_initsize); 112 113 return tcb; 114 } 115 116 __weak_alias(_rtld_tls_free, __libc_rtld_tls_free) 117 118 void 119 _rtld_tls_free(struct tls_tcb *tcb) 120 { 121 uint8_t *p; 122 123 #ifdef __HAVE_TLS_VARIANT_I 124 /* LINTED */ 125 p = (uint8_t *)tcb; 126 #else 127 /* LINTED */ 128 p = (uint8_t *)tcb - tls_size; 129 #endif 130 if (p == initial_thread_tcb) 131 munmap(p, tls_allocation); 132 else 133 free(p); 134 } 135 136 static int __section(".text.startup") 137 __libc_static_tls_setup_cb(struct dl_phdr_info *data, size_t len, void *cookie) 138 { 139 const Elf_Phdr *phdr = data->dlpi_phdr; 140 const Elf_Phdr *phlimit = data->dlpi_phdr + data->dlpi_phnum; 141 142 for (; phdr < phlimit; ++phdr) { 143 if (phdr->p_type == PT_INTERP) { 144 is_dynamic = true; 145 return -1; 146 } 147 if (phdr->p_type != PT_TLS) 148 continue; 149 tls_initaddr = (void *)(phdr->p_vaddr + data->dlpi_addr); 150 tls_initsize = phdr->p_filesz; 151 tls_size = phdr->p_memsz; 152 } 153 return 0; 154 } 155 156 void 157 __libc_static_tls_setup(void) 158 { 159 struct tls_tcb *tcb; 160 161 dl_iterate_phdr(__libc_static_tls_setup_cb, NULL); 162 if (is_dynamic) 163 return; 164 165 tcb = _rtld_tls_allocate(); 166 #ifdef __HAVE___LWP_SETTCB 167 __lwp_settcb(tcb); 168 #else 169 _lwp_setprivate(tcb); 170 #endif 171 } 172 173 #endif /* __HAVE_TLS_VARIANT_I || __HAVE_TLS_VARIANT_II */ 174