1/*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 1998 John D. Polstra 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29#if !defined(IN_LIBDL) || defined(PIC) 30 31/* 32 * Linkage to services provided by the dynamic linker. 33 */ 34#include <sys/types.h> 35#include <sys/mman.h> 36#include <machine/atomic.h> 37#include <dlfcn.h> 38#include <link.h> 39#include <stddef.h> 40#include <string.h> 41#include "namespace.h" 42#include <pthread.h> 43#include "un-namespace.h" 44#include "rtld.h" 45#include "libc_private.h" 46#include "reentrant.h" 47 48static const char sorry[] = "Service unavailable"; 49 50void _rtld_thread_init(void *); 51void _rtld_atfork_pre(int *); 52void _rtld_atfork_post(int *); 53 54/* 55 * For ELF, the dynamic linker directly resolves references to its 56 * services to functions inside the dynamic linker itself. These 57 * weak-symbol stubs are necessary so that "ld" won't complain about 58 * undefined symbols. The stubs are executed only when the program is 59 * linked statically, or when a given service isn't implemented in the 60 * dynamic linker. They must return an error if called, and they must 61 * be weak symbols so that the dynamic linker can override them. 62 */ 63 64#pragma weak _rtld_error 65void 66_rtld_error(const char *fmt __unused, ...) 67{ 68} 69 70#pragma weak dladdr 71int 72dladdr(const void *addr __unused, Dl_info *dlip __unused) 73{ 74 75 _rtld_error(sorry); 76 return (0); 77} 78 79#pragma weak dlclose 80int 81dlclose(void *handle __unused) 82{ 83 84 _rtld_error(sorry); 85 return (-1); 86} 87 88#pragma weak dlerror 89char * 90dlerror(void) 91{ 92 93 return (__DECONST(char *, sorry)); 94} 95 96#pragma weak dllockinit 97void 98dllockinit(void *context, 99 void *(*lock_create)(void *context) __unused, 100 void (*rlock_acquire)(void *lock) __unused, 101 void (*wlock_acquire)(void *lock) __unused, 102 void (*lock_release)(void *lock) __unused, 103 void (*lock_destroy)(void *lock) __unused, 104 void (*context_destroy)(void *context) __unused) 105{ 106 107 if (context_destroy != NULL) 108 context_destroy(context); 109} 110 111#pragma weak dlopen 112void * 113dlopen(const char *name __unused, int mode __unused) 114{ 115 116 _rtld_error(sorry); 117 return (NULL); 118} 119 120#pragma weak dlsym 121void * 122dlsym(void * __restrict handle __unused, const char * __restrict name __unused) 123{ 124 125 _rtld_error(sorry); 126 return (NULL); 127} 128 129#pragma weak dlfunc 130dlfunc_t 131dlfunc(void * __restrict handle __unused, const char * __restrict name __unused) 132{ 133 134 _rtld_error(sorry); 135 return (NULL); 136} 137 138#pragma weak dlvsym 139void * 140dlvsym(void * __restrict handle __unused, const char * __restrict name __unused, 141 const char * __restrict version __unused) 142{ 143 144 _rtld_error(sorry); 145 return (NULL); 146} 147 148#pragma weak dlinfo 149int 150dlinfo(void * __restrict handle __unused, int request __unused, 151 void * __restrict p __unused) 152{ 153 154 _rtld_error(sorry); 155 return (0); 156} 157 158#pragma weak _rtld_thread_init 159void 160_rtld_thread_init(void *li __unused) 161{ 162 163 _rtld_error(sorry); 164} 165 166#ifndef IN_LIBDL 167static pthread_once_t dl_phdr_info_once = PTHREAD_ONCE_INIT; 168static struct dl_phdr_info phdr_info; 169#ifndef PIC 170static mutex_t dl_phdr_info_lock = MUTEX_INITIALIZER; 171#endif 172 173static void 174dl_init_phdr_info(void) 175{ 176 Elf_Auxinfo *auxp; 177 unsigned int i; 178 179 for (auxp = __elf_aux_vector; auxp->a_type != AT_NULL; auxp++) { 180 switch (auxp->a_type) { 181 case AT_BASE: 182 phdr_info.dlpi_addr = (Elf_Addr)auxp->a_un.a_ptr; 183 break; 184 case AT_EXECPATH: 185 phdr_info.dlpi_name = (const char *)auxp->a_un.a_ptr; 186 break; 187 case AT_PHDR: 188 phdr_info.dlpi_phdr = 189 (const Elf_Phdr *)auxp->a_un.a_ptr; 190 break; 191 case AT_PHNUM: 192 phdr_info.dlpi_phnum = (Elf_Half)auxp->a_un.a_val; 193 break; 194 } 195 } 196 for (i = 0; i < phdr_info.dlpi_phnum; i++) { 197 if (phdr_info.dlpi_phdr[i].p_type == PT_TLS) { 198 phdr_info.dlpi_tls_modid = 1; 199 } 200 } 201 phdr_info.dlpi_adds = 1; 202} 203#endif 204 205#pragma weak dl_iterate_phdr 206int 207dl_iterate_phdr(int (*callback)(struct dl_phdr_info *, size_t, void *) __unused, 208 void *data __unused) 209{ 210#if defined IN_LIBDL 211 return (0); 212#elif defined PIC 213 int (*r)(int (*)(struct dl_phdr_info *, size_t, void *), void *); 214 215 r = dlsym(RTLD_DEFAULT, "dl_iterate_phdr"); 216 if (r == NULL) 217 return (0); 218 return (r(callback, data)); 219#else 220 tls_index ti; 221 int ret; 222 223 __init_elf_aux_vector(); 224 if (__elf_aux_vector == NULL) 225 return (1); 226 _once(&dl_phdr_info_once, dl_init_phdr_info); 227 ti.ti_module = 1; 228 ti.ti_offset = 0; 229 mutex_lock(&dl_phdr_info_lock); 230 phdr_info.dlpi_tls_data = __tls_get_addr(&ti); 231 ret = callback(&phdr_info, sizeof(phdr_info), data); 232 mutex_unlock(&dl_phdr_info_lock); 233 return (ret); 234#endif 235} 236 237#pragma weak fdlopen 238void * 239fdlopen(int fd __unused, int mode __unused) 240{ 241 242 _rtld_error(sorry); 243 return (NULL); 244} 245 246#pragma weak _rtld_atfork_pre 247void 248_rtld_atfork_pre(int *locks __unused) 249{ 250} 251 252#pragma weak _rtld_atfork_post 253void 254_rtld_atfork_post(int *locks __unused) 255{ 256} 257 258#ifndef IN_LIBDL 259struct _rtld_addr_phdr_cb_data { 260 const void *addr; 261 struct dl_phdr_info *dli; 262}; 263 264static int 265_rtld_addr_phdr_cb(struct dl_phdr_info *dli, size_t sz, void *arg) 266{ 267 struct _rtld_addr_phdr_cb_data *rd; 268 const Elf_Phdr *ph; 269 unsigned i; 270 271 rd = arg; 272 for (i = 0; i < dli->dlpi_phnum; i++) { 273 ph = &dli->dlpi_phdr[i]; 274 if (ph->p_type == PT_LOAD && 275 dli->dlpi_addr + ph->p_vaddr <= (uintptr_t)rd->addr && 276 (uintptr_t)rd->addr < dli->dlpi_addr + ph->p_vaddr + 277 ph->p_memsz) { 278 memcpy(rd->dli, dli, sz); 279 return (1); 280 } 281 } 282 return (0); 283} 284#endif 285 286#pragma weak _rtld_addr_phdr 287int 288_rtld_addr_phdr(const void *addr __unused, 289 struct dl_phdr_info *phdr_info_a __unused) 290{ 291#ifndef IN_LIBDL 292 struct _rtld_addr_phdr_cb_data rd; 293 294 rd.addr = addr; 295 rd.dli = phdr_info_a; 296 return (dl_iterate_phdr(_rtld_addr_phdr_cb, &rd)); 297#else 298 return (0); 299#endif 300} 301 302#pragma weak _rtld_get_stack_prot 303int 304_rtld_get_stack_prot(void) 305{ 306#ifndef IN_LIBDL 307 unsigned i; 308 int r; 309 static int ret; 310 311 r = atomic_load_int(&ret); 312 if (r != 0) 313 return (r); 314 315 _once(&dl_phdr_info_once, dl_init_phdr_info); 316 r = PROT_EXEC | PROT_READ | PROT_WRITE; 317 for (i = 0; i < phdr_info.dlpi_phnum; i++) { 318 if (phdr_info.dlpi_phdr[i].p_type != PT_GNU_STACK) 319 continue; 320 r = PROT_READ | PROT_WRITE; 321 if ((phdr_info.dlpi_phdr[i].p_flags & PF_X) != 0) 322 r |= PROT_EXEC; 323 break; 324 } 325 atomic_store_int(&ret, r); 326 return (r); 327#else 328 return (0); 329#endif 330} 331 332#pragma weak _rtld_is_dlopened 333int 334_rtld_is_dlopened(void *arg __unused) 335{ 336 337 return (0); 338} 339 340#endif /* !defined(IN_LIBDL) || defined(PIC) */ 341