2 * Copyright (c) 1998 John D. Polstra
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * $FreeBSD: src/lib/libc/gen/dlfcn.c 217154 2011-01-08 17:13:43Z kib $
34 #include "libc_private.h"
36 struct dl_phdr_info build_phdr_info(void);
37 void _rtld_thread_childfork(void);
38 void _rtld_thread_init(void *);
39 void _rtld_thread_postfork(void);
40 void _rtld_thread_prefork(void);
42 extern char **environ;
44 static char sorry[] = "Service unavailable";
47 * For ELF, the dynamic linker directly resolves references to its
48 * services to functions inside the dynamic linker itself. These
49 * weak-symbol stubs are necessary so that "ld" won't complain about
50 * undefined symbols. The stubs are executed only when the program is
51 * linked statically, or when a given service isn't implemented in the
52 * dynamic linker. They must return an error if called, and they must
53 * be weak symbols so that the dynamic linker can override them.
56 #pragma weak _rtld_error
58 _rtld_error(const char *fmt __unused, ...)
64 dladdr(const void *addr __unused, Dl_info *dlip __unused)
72 dlclose(void *handle __unused)
87 dlopen(const char *name __unused, int mode __unused)
95 dlsym(void *handle __unused, const char *name __unused)
103 dlfunc(void * handle __unused, const char * name __unused)
111 dlvsym(void *handle __unused,const char *name __unused,
112 const char *version __unused)
118 #pragma weak _rtld_thread_init
120 _rtld_thread_init(void * li __unused)
127 dlinfo(void *handle __unused, int request __unused, void *p __unused)
133 __dso_hidden struct dl_phdr_info
134 build_phdr_info(void)
136 struct dl_phdr_info phdr_info;
138 Elf_Auxinfo *aux, *auxp;
141 sp = (Elf_Addr *) environ;
144 aux = (Elf_Auxinfo *) sp;
145 memset (&phdr_info, 0, sizeof(phdr_info));
146 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
147 switch (auxp->a_type) {
149 phdr_info.dlpi_addr = (Elf_Addr) auxp->a_un.a_ptr;
152 phdr_info.dlpi_name = (const char *) auxp->a_un.a_ptr;
155 phdr_info.dlpi_phdr = (const Elf_Phdr *) auxp->a_un.a_ptr;
158 phdr_info.dlpi_phnum = (Elf_Half) auxp->a_un.a_val;
163 for (i = 0; i < phdr_info.dlpi_phnum; i++)
164 if (phdr_info.dlpi_phdr[i].p_type == PT_TLS) {
165 phdr_info.dlpi_tls_modid = 1;
166 phdr_info.dlpi_tls_data =
167 (void*)phdr_info.dlpi_phdr[i].p_vaddr;
173 #pragma weak dl_iterate_phdr
175 dl_iterate_phdr(int (*callback)(struct dl_phdr_info *, size_t, void *),
179 static struct dl_phdr_info phdr_info;
182 phdr_info = build_phdr_info();
185 return callback(&phdr_info, sizeof(phdr_info), data);
190 fdlopen(int fd __unused, int mode __unused)
196 #pragma weak _rtld_addr_phdr
198 _rtld_addr_phdr(const void *addr __unused,
199 struct dl_phdr_info *phdr_info __unused)
205 #pragma weak _rtld_get_stack_prot
207 _rtld_get_stack_prot(void)
209 return (PROT_EXEC | PROT_READ | PROT_WRITE);
212 #pragma weak _rtld_thread_prefork
214 _rtld_thread_prefork(void)
218 #pragma weak _rtld_thread_postfork
220 _rtld_thread_postfork(void)
224 #pragma weak _rtld_thread_childfork
226 _rtld_thread_childfork(void)