2 * SPDX-License-Identifier: BSD-2-Clause
4 * Copyright (c) 1998 John D. Polstra
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
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.
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
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
32 #if !defined(IN_LIBDL) || defined(PIC)
35 * Linkage to services provided by the dynamic linker.
37 #include <sys/types.h>
39 #include <machine/atomic.h>
44 #include "namespace.h"
46 #include "un-namespace.h"
48 #include "libc_private.h"
49 #include "reentrant.h"
51 static const char sorry[] = "Service unavailable";
53 void _rtld_thread_init(void *);
54 void _rtld_atfork_pre(int *);
55 void _rtld_atfork_post(int *);
58 * For ELF, the dynamic linker directly resolves references to its
59 * services to functions inside the dynamic linker itself. These
60 * weak-symbol stubs are necessary so that "ld" won't complain about
61 * undefined symbols. The stubs are executed only when the program is
62 * linked statically, or when a given service isn't implemented in the
63 * dynamic linker. They must return an error if called, and they must
64 * be weak symbols so that the dynamic linker can override them.
67 #pragma weak _rtld_error
69 _rtld_error(const char *fmt __unused, ...)
75 dladdr(const void *addr __unused, Dl_info *dlip __unused)
84 dlclose(void *handle __unused)
96 return (__DECONST(char *, sorry));
99 #pragma weak dllockinit
101 dllockinit(void *context,
102 void *(*lock_create)(void *context) __unused,
103 void (*rlock_acquire)(void *lock) __unused,
104 void (*wlock_acquire)(void *lock) __unused,
105 void (*lock_release)(void *lock) __unused,
106 void (*lock_destroy)(void *lock) __unused,
107 void (*context_destroy)(void *context) __unused)
110 if (context_destroy != NULL)
111 context_destroy(context);
116 dlopen(const char *name __unused, int mode __unused)
125 dlsym(void * __restrict handle __unused, const char * __restrict name __unused)
134 dlfunc(void * __restrict handle __unused, const char * __restrict name __unused)
143 dlvsym(void * __restrict handle __unused, const char * __restrict name __unused,
144 const char * __restrict version __unused)
153 dlinfo(void * __restrict handle __unused, int request __unused,
154 void * __restrict p __unused)
161 #pragma weak _rtld_thread_init
163 _rtld_thread_init(void *li __unused)
170 static pthread_once_t dl_phdr_info_once = PTHREAD_ONCE_INIT;
171 static struct dl_phdr_info phdr_info;
173 static mutex_t dl_phdr_info_lock = MUTEX_INITIALIZER;
177 dl_init_phdr_info(void)
182 for (auxp = __elf_aux_vector; auxp->a_type != AT_NULL; auxp++) {
183 switch (auxp->a_type) {
185 phdr_info.dlpi_addr = (Elf_Addr)auxp->a_un.a_ptr;
188 phdr_info.dlpi_name = (const char *)auxp->a_un.a_ptr;
191 phdr_info.dlpi_phdr =
192 (const Elf_Phdr *)auxp->a_un.a_ptr;
195 phdr_info.dlpi_phnum = (Elf_Half)auxp->a_un.a_val;
199 for (i = 0; i < phdr_info.dlpi_phnum; i++) {
200 if (phdr_info.dlpi_phdr[i].p_type == PT_TLS) {
201 phdr_info.dlpi_tls_modid = 1;
204 phdr_info.dlpi_adds = 1;
208 #pragma weak dl_iterate_phdr
210 dl_iterate_phdr(int (*callback)(struct dl_phdr_info *, size_t, void *) __unused,
216 int (*r)(int (*)(struct dl_phdr_info *, size_t, void *), void *);
218 r = dlsym(RTLD_DEFAULT, "dl_iterate_phdr");
221 return (r(callback, data));
226 __init_elf_aux_vector();
227 if (__elf_aux_vector == NULL)
229 _once(&dl_phdr_info_once, dl_init_phdr_info);
232 mutex_lock(&dl_phdr_info_lock);
233 phdr_info.dlpi_tls_data = __tls_get_addr(&ti);
234 ret = callback(&phdr_info, sizeof(phdr_info), data);
235 mutex_unlock(&dl_phdr_info_lock);
242 fdlopen(int fd __unused, int mode __unused)
249 #pragma weak _rtld_atfork_pre
251 _rtld_atfork_pre(int *locks __unused)
255 #pragma weak _rtld_atfork_post
257 _rtld_atfork_post(int *locks __unused)
262 struct _rtld_addr_phdr_cb_data {
264 struct dl_phdr_info *dli;
268 _rtld_addr_phdr_cb(struct dl_phdr_info *dli, size_t sz, void *arg)
270 struct _rtld_addr_phdr_cb_data *rd;
275 for (i = 0; i < dli->dlpi_phnum; i++) {
276 ph = &dli->dlpi_phdr[i];
277 if (ph->p_type == PT_LOAD &&
278 dli->dlpi_addr + ph->p_vaddr <= (uintptr_t)rd->addr &&
279 (uintptr_t)rd->addr < dli->dlpi_addr + ph->p_vaddr +
281 memcpy(rd->dli, dli, sz);
289 #pragma weak _rtld_addr_phdr
291 _rtld_addr_phdr(const void *addr __unused,
292 struct dl_phdr_info *phdr_info_a __unused)
295 struct _rtld_addr_phdr_cb_data rd;
298 rd.dli = phdr_info_a;
299 return (dl_iterate_phdr(_rtld_addr_phdr_cb, &rd));
305 #pragma weak _rtld_get_stack_prot
307 _rtld_get_stack_prot(void)
314 r = atomic_load_int(&ret);
318 _once(&dl_phdr_info_once, dl_init_phdr_info);
319 r = PROT_EXEC | PROT_READ | PROT_WRITE;
320 for (i = 0; i < phdr_info.dlpi_phnum; i++) {
321 if (phdr_info.dlpi_phdr[i].p_type != PT_GNU_STACK)
323 r = PROT_READ | PROT_WRITE;
324 if ((phdr_info.dlpi_phdr[i].p_flags & PF_X) != 0)
328 atomic_store_int(&ret, r);
335 #pragma weak _rtld_is_dlopened
337 _rtld_is_dlopened(void *arg __unused)
343 #endif /* !defined(IN_LIBDL) || defined(PIC) */