/* $NetBSD: dlfcn_elf.c,v 1.16 2018/07/13 19:49:47 joerg Exp $ */ /* * Copyright (c) 2000 Takuya SHIOZAKI * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #include #if defined(LIBC_SCCS) && !defined(lint) __RCSID("$NetBSD: dlfcn_elf.c,v 1.16 2018/07/13 19:49:47 joerg Exp $"); #endif /* LIBC_SCCS and not lint */ #include "namespace.h" #include #include #include #include #include #include #undef dl_iterate_phdr #undef dlopen #undef dlclose #undef dlsym #undef dlerror #undef dladdr #undef dfinfo #define dlopen ___dlopen #define dlclose ___dlclose #define dlsym ___dlsym #define dlvsym ___dlvsym #define dlerror ___dlerror #define dladdr ___dladdr #define dlinfo ___dlinfo #define dl_iterate_phdr ___dl_iterate_phdr #define ELFSIZE ARCH_ELFSIZE #include "rtld.h" #ifdef __weak_alias __weak_alias(dlopen,___dlopen) __weak_alias(dlclose,___dlclose) __weak_alias(dlsym,___dlsym) __weak_alias(dlvsym,___dlvsym) __weak_alias(dlerror,___dlerror) __weak_alias(dladdr,___dladdr) __weak_alias(dlinfo,___dlinfo) __weak_alias(dl_iterate_phdr,___dl_iterate_phdr) __weak_alias(__dlopen,___dlopen) __weak_alias(__dlclose,___dlclose) __weak_alias(__dlsym,___dlsym) __weak_alias(__dlvsym,___dlvsym) __weak_alias(__dlerror,___dlerror) __weak_alias(__dladdr,___dladdr) __weak_alias(__dlinfo,___dlinfo) __weak_alias(__dl_iterate_phdr,___dl_iterate_phdr) __weak_alias(__dl_cxa_refcount, ___dl_cxa_refcount) #endif /* * For ELF, the dynamic linker directly resolves references to its * services to functions inside the dynamic linker itself. These * weak-symbol stubs are necessary so that "ld" won't complain about * undefined symbols. The stubs are executed only when the program is * linked statically, or when a given service isn't implemented in the * dynamic linker. They must return an error if called, and they must * be weak symbols so that the dynamic linker can override them. */ static char dlfcn_error[] = "Service unavailable"; /*ARGSUSED*/ void * dlopen(const char *name, int mode) { return NULL; } /*ARGSUSED*/ int dlclose(void *fd) { return -1; } /*ARGSUSED*/ void * dlsym(void *handle, const char *name) { return NULL; } /*ARGSUSED*/ void * dlvsym(void *handle, const char *name, const char *version) { return NULL; } /*ARGSUSED*/ __aconst char * dlerror(void) { return dlfcn_error; } /*ARGSUSED*/ int dladdr(const void *addr, Dl_info *dli) { return 0; } /*ARGSUSED*/ int dlinfo(void *handle, int req, void *v) { return -1; } static const char *dlpi_name; static Elf_Addr dlpi_addr; static const Elf_Phdr *dlpi_phdr; static Elf_Half dlpi_phnum; static void dl_iterate_phdr_setup(void) { const AuxInfo *aux; _DIAGASSERT(_dlauxinfo() != NULL); for (aux = _dlauxinfo(); aux->a_type != AT_NULL; ++aux) { switch (aux->a_type) { case AT_BASE: dlpi_addr = aux->a_v; break; case AT_PHDR: dlpi_phdr = (void *)aux->a_v; break; case AT_PHNUM: _DIAGASSERT(__type_fit(Elf_Half, aux->a_v)); dlpi_phnum = (Elf_Half)aux->a_v; break; case AT_SUN_EXECNAME: dlpi_name = (void *)aux->a_v; break; } } if (!dlpi_phdr) return; const Elf_Phdr *phdr = (const Elf_Phdr *)dlpi_phdr; const Elf_Phdr *phlimit = phdr + dlpi_phnum; for (; phdr < phlimit; ++phdr) { if (phdr->p_type == PT_PHDR) dlpi_addr = (uintptr_t)phdr - phdr->p_vaddr; } } /*ARGSUSED*/ int dl_iterate_phdr(int (*callback)(struct dl_phdr_info *, size_t, void *), void *data) { static bool setup_done; struct dl_phdr_info phdr_info; if (!setup_done) { /* * This can race on the first call to dl_iterate_phdr. * dl_iterate_phdr_setup only touches field of pointer size * and smaller and such stores are atomic. */ dl_iterate_phdr_setup(); membar_producer(); setup_done = true; } memset(&phdr_info, 0, sizeof(phdr_info)); phdr_info.dlpi_addr = dlpi_addr; phdr_info.dlpi_phdr = dlpi_phdr; phdr_info.dlpi_phnum = dlpi_phnum; phdr_info.dlpi_name = dlpi_name; return callback(&phdr_info, sizeof(phdr_info), data); } void ___dl_cxa_refcount(void *, ssize_t); /*ARGSUSED*/ void ___dl_cxa_refcount(void *dso_symbol, ssize_t delta) { }