tls.c revision 1.15
1 /* $NetBSD: tls.c,v 1.15 2024/01/20 14:52:49 christos 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 1.15 2024/01/20 14:52:49 christos 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 <stdalign.h> 50 #include <stddef.h> 51 #include <stdlib.h> 52 #include <string.h> 53 #include <unistd.h> 54 55 __dso_hidden void __libc_static_tls_setup(void); 56 57 static bool is_dynamic; 58 static const void *tls_initaddr; 59 static size_t tls_initsize; 60 static size_t tls_size; 61 static size_t tls_allocation; 62 static void *initial_thread_tcb; 63 64 void * __libc_tls_get_addr(void); 65 66 __weak_alias(__tls_get_addr, __libc_tls_get_addr) 67 #ifdef __i386__ 68 __weak_alias(___tls_get_addr, __libc_tls_get_addr) 69 #endif 70 71 void * 72 __libc_tls_get_addr(void) 73 { 74 75 abort(); 76 /* NOTREACHED */ 77 } 78 79 __weak_alias(_rtld_tls_allocate, __libc_rtld_tls_allocate) 80 81 struct tls_tcb * 82 _rtld_tls_allocate(void) 83 { 84 struct tls_tcb *tcb; 85 uint8_t *p; 86 87 if (initial_thread_tcb == NULL) { 88 #ifdef __HAVE_TLS_VARIANT_I 89 tls_allocation = tls_size; 90 #else 91 tls_allocation = roundup2(tls_size, alignof(max_align_t)); 92 #endif 93 94 initial_thread_tcb = p = mmap(NULL, 95 tls_allocation + sizeof(*tcb), PROT_READ | PROT_WRITE, 96 MAP_ANON, -1, 0); 97 if (p == MAP_FAILED) 98 initial_thread_tcb = p = NULL; 99 } else { 100 p = calloc(1, tls_allocation + sizeof(*tcb)); 101 } 102 if (p == NULL) { 103 static const char msg[] = "TLS allocation failed, terminating\n"; 104 write(STDERR_FILENO, msg, sizeof(msg)); 105 _exit(127); 106 } 107 #ifdef __HAVE_TLS_VARIANT_I 108 /* LINTED */ 109 tcb = (struct tls_tcb *)p; 110 p += sizeof(struct tls_tcb); 111 #else 112 /* LINTED tls_size is rounded above */ 113 tcb = (struct tls_tcb *)(p + tls_allocation); 114 p = (uint8_t *)tcb - tls_size; 115 tcb->tcb_self = tcb; 116 #endif 117 memcpy(p, tls_initaddr, tls_initsize); 118 119 return tcb; 120 } 121 122 __weak_alias(_rtld_tls_free, __libc_rtld_tls_free) 123 124 void 125 _rtld_tls_free(struct tls_tcb *tcb) 126 { 127 uint8_t *p; 128 129 #ifdef __HAVE_TLS_VARIANT_I 130 /* LINTED */ 131 p = (uint8_t *)tcb; 132 #else 133 /* LINTED */ 134 p = (uint8_t *)tcb - tls_allocation; 135 #endif 136 if (p == initial_thread_tcb) 137 munmap(p, tls_allocation + sizeof(*tcb)); 138 else 139 free(p); 140 } 141 142 static int __section(".text.startup") 143 /*ARGSUSED*/ 144 __libc_static_tls_setup_cb(struct dl_phdr_info *data, size_t len, void *cookie) 145 { 146 const Elf_Phdr *phdr = data->dlpi_phdr; 147 const Elf_Phdr *phlimit = data->dlpi_phdr + data->dlpi_phnum; 148 149 for (; phdr < phlimit; ++phdr) { 150 if (phdr->p_type == PT_INTERP) { 151 is_dynamic = true; 152 return -1; 153 } 154 if (phdr->p_type != PT_TLS) 155 continue; 156 tls_initaddr = (void *)(phdr->p_vaddr + data->dlpi_addr); 157 tls_initsize = phdr->p_filesz; 158 #ifdef __HAVE_TLS_VARIANT_I 159 tls_size = phdr->p_memsz; 160 #else 161 tls_size = roundup2(phdr->p_memsz, phdr->p_align); 162 #endif 163 } 164 return 0; 165 } 166 167 void 168 __libc_static_tls_setup(void) 169 { 170 struct tls_tcb *tcb; 171 172 dl_iterate_phdr(__libc_static_tls_setup_cb, NULL); 173 if (is_dynamic) 174 return; 175 176 tcb = _rtld_tls_allocate(); 177 #ifdef __HAVE___LWP_SETTCB 178 __lwp_settcb(tcb); 179 #else 180 _lwp_setprivate(tcb); 181 #endif 182 } 183 184 #endif /* __HAVE_TLS_VARIANT_I || __HAVE_TLS_VARIANT_II */ 185
Indexes created Sat Sep 20 22:09:52 GMT 2025