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);
41 void _rtld_setthreaded(void);
43 extern char **environ;
45 static char sorry[] = "Service unavailable";
48 * For ELF, the dynamic linker directly resolves references to its
49 * services to functions inside the dynamic linker itself. These
50 * weak-symbol stubs are necessary so that "ld" won't complain about
51 * undefined symbols. The stubs are executed only when the program is
52 * linked statically, or when a given service isn't implemented in the
53 * dynamic linker. They must return an error if called, and they must
54 * be weak symbols so that the dynamic linker can override them.
57 #pragma weak _rtld_error
59 _rtld_error(const char *fmt __unused, ...)
65 dladdr(const void *addr __unused, Dl_info *dlip __unused)
73 dlclose(void *handle __unused)
88 dlopen(const char *name __unused, int mode __unused)
96 dlsym(void *handle __unused, const char *name __unused)
104 dlfunc(void * handle __unused, const char * name __unused)
112 dlvsym(void *handle __unused,const char *name __unused,
113 const char *version __unused)
119 #pragma weak _rtld_thread_init
121 _rtld_thread_init(void * li __unused)
128 dlinfo(void *handle __unused, int request __unused, void *p __unused)
134 __dso_hidden struct dl_phdr_info
135 build_phdr_info(void)
137 struct dl_phdr_info phdr_info;
139 Elf_Auxinfo *aux, *auxp;
142 sp = (Elf_Addr *) environ;
145 aux = (Elf_Auxinfo *) sp;
146 memset (&phdr_info, 0, sizeof(phdr_info));
147 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
148 switch (auxp->a_type) {
150 phdr_info.dlpi_addr = (Elf_Addr) auxp->a_un.a_ptr;
153 phdr_info.dlpi_name = (const char *) auxp->a_un.a_ptr;
156 phdr_info.dlpi_phdr = (const Elf_Phdr *) auxp->a_un.a_ptr;
159 phdr_info.dlpi_phnum = (Elf_Half) auxp->a_un.a_val;
164 for (i = 0; i < phdr_info.dlpi_phnum; i++)
165 if (phdr_info.dlpi_phdr[i].p_type == PT_TLS) {
166 phdr_info.dlpi_tls_modid = 1;
167 phdr_info.dlpi_tls_data =
168 (void*)phdr_info.dlpi_phdr[i].p_vaddr;
174 #pragma weak dl_iterate_phdr
176 dl_iterate_phdr(int (*callback)(struct dl_phdr_info *, size_t, void *),
180 static struct dl_phdr_info phdr_info;
183 phdr_info = build_phdr_info();
186 return callback(&phdr_info, sizeof(phdr_info), data);
191 fdlopen(int fd __unused, int mode __unused)
197 #pragma weak _rtld_addr_phdr
199 _rtld_addr_phdr(const void *addr __unused,
200 struct dl_phdr_info *phdr_info __unused)
206 #pragma weak _rtld_get_stack_prot
208 _rtld_get_stack_prot(void)
210 return (PROT_EXEC | PROT_READ | PROT_WRITE);
213 #pragma weak _rtld_thread_prefork
215 _rtld_thread_prefork(void)
219 #pragma weak _rtld_thread_postfork
221 _rtld_thread_postfork(void)
225 #pragma weak _rtld_thread_childfork
227 _rtld_thread_childfork(void)
231 #pragma weak _rtld_setthreaded
233 _rtld_setthreaded(void)