| /* loader-dlopen.c -- dynamic linking with dlopen/dlsym |
| |
| Copyright (C) 1998, 1999, 2000, 2004, 2006, |
| 2007, 2008 Free Software Foundation, Inc. |
| Written by Thomas Tanner, 1998 |
| |
| NOTE: The canonical source of this file is maintained with the |
| GNU Libtool package. Report bugs to bug-libtool@gnu.org. |
| |
| GNU Libltdl is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2 of the License, or (at your option) any later version. |
| |
| As a special exception to the GNU Lesser General Public License, |
| if you distribute this file as part of a program or library that |
| is built using GNU Libtool, you may include this file under the |
| same distribution terms that you use for the rest of that program. |
| |
| GNU Libltdl is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with GNU Libltdl; see the file COPYING.LIB. If not, a |
| copy can be downloaded from http://www.gnu.org/licenses/lgpl.html, |
| or obtained by writing to the Free Software Foundation, Inc., |
| 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. |
| */ |
| |
| #include "lt__private.h" |
| #include "lt_dlloader.h" |
| |
| /* Use the preprocessor to rename non-static symbols to avoid namespace |
| collisions when the loader code is statically linked into libltdl. |
| Use the "<module_name>_LTX_" prefix so that the symbol addresses can |
| be fetched from the preloaded symbol list by lt_dlsym(): */ |
| #define get_vtable dlopen_LTX_get_vtable |
| |
| LT_BEGIN_C_DECLS |
| LT_SCOPE lt_dlvtable *get_vtable (lt_user_data loader_data); |
| LT_END_C_DECLS |
| |
| |
| /* Boilerplate code to set up the vtable for hooking this loader into |
| libltdl's loader list: */ |
| static int vl_exit (lt_user_data loader_data); |
| static lt_module vm_open (lt_user_data loader_data, const char *filename, |
| lt_dladvise advise); |
| static int vm_close (lt_user_data loader_data, lt_module module); |
| static void * vm_sym (lt_user_data loader_data, lt_module module, |
| const char *symbolname); |
| |
| static lt_dlvtable *vtable = 0; |
| |
| /* Return the vtable for this loader, only the name and sym_prefix |
| attributes (plus the virtual function implementations, obviously) |
| change between loaders. */ |
| lt_dlvtable * |
| get_vtable (lt_user_data loader_data) |
| { |
| if (!vtable) |
| { |
| vtable = (lt_dlvtable *) lt__zalloc (sizeof *vtable); |
| } |
| |
| if (vtable && !vtable->name) |
| { |
| vtable->name = "lt_dlopen"; |
| #if defined(DLSYM_USCORE) |
| vtable->sym_prefix = "_"; |
| #endif |
| vtable->module_open = vm_open; |
| vtable->module_close = vm_close; |
| vtable->find_sym = vm_sym; |
| vtable->dlloader_exit = vl_exit; |
| vtable->dlloader_data = loader_data; |
| vtable->priority = LT_DLLOADER_PREPEND; |
| } |
| |
| if (vtable && (vtable->dlloader_data != loader_data)) |
| { |
| LT__SETERROR (INIT_LOADER); |
| return 0; |
| } |
| |
| return vtable; |
| } |
| |
| |
| |
| /* --- IMPLEMENTATION --- */ |
| |
| |
| #if defined(HAVE_DLFCN_H) |
| # include <dlfcn.h> |
| #endif |
| |
| #if defined(HAVE_SYS_DL_H) |
| # include <sys/dl.h> |
| #endif |
| |
| |
| /* We may have to define LT_LAZY_OR_NOW in the command line if we |
| find out it does not work in some platform. */ |
| #if !defined(LT_LAZY_OR_NOW) |
| # if defined(RTLD_LAZY) |
| # define LT_LAZY_OR_NOW RTLD_LAZY |
| # else |
| # if defined(DL_LAZY) |
| # define LT_LAZY_OR_NOW DL_LAZY |
| # endif |
| # endif /* !RTLD_LAZY */ |
| #endif |
| #if !defined(LT_LAZY_OR_NOW) |
| # if defined(RTLD_NOW) |
| # define LT_LAZY_OR_NOW RTLD_NOW |
| # else |
| # if defined(DL_NOW) |
| # define LT_LAZY_OR_NOW DL_NOW |
| # endif |
| # endif /* !RTLD_NOW */ |
| #endif |
| #if !defined(LT_LAZY_OR_NOW) |
| # define LT_LAZY_OR_NOW 0 |
| #endif /* !LT_LAZY_OR_NOW */ |
| |
| /* We only support local and global symbols from modules for loaders |
| that provide such a thing, otherwise the system default is used. */ |
| #if !defined(RTLD_GLOBAL) |
| # if defined(DL_GLOBAL) |
| # define RTLD_GLOBAL DL_GLOBAL |
| # endif |
| #endif /* !RTLD_GLOBAL */ |
| #if !defined(RTLD_LOCAL) |
| # if defined(DL_LOCAL) |
| # define RTLD_LOCAL DL_LOCAL |
| # endif |
| #endif /* !RTLD_LOCAL */ |
| |
| #if defined(HAVE_DLERROR) |
| # define DLERROR(arg) dlerror () |
| #else |
| # define DLERROR(arg) LT__STRERROR (arg) |
| #endif |
| |
| #define DL__SETERROR(errorcode) \ |
| LT__SETERRORSTR (DLERROR (errorcode)) |
| |
| |
| /* A function called through the vtable when this loader is no |
| longer needed by the application. */ |
| static int |
| vl_exit (lt_user_data LT__UNUSED loader_data) |
| { |
| vtable = NULL; |
| return 0; |
| } |
| |
| |
| /* A function called through the vtable to open a module with this |
| loader. Returns an opaque representation of the newly opened |
| module for processing with this loader's other vtable functions. */ |
| static lt_module |
| vm_open (lt_user_data LT__UNUSED loader_data, const char *filename, |
| lt_dladvise advise) |
| { |
| int module_flags = LT_LAZY_OR_NOW; |
| lt_module module; |
| |
| if (advise) |
| { |
| #ifdef RTLD_GLOBAL |
| /* If there is some means of asking for global symbol resolution, |
| do so. */ |
| if (advise->is_symglobal) |
| module_flags |= RTLD_GLOBAL; |
| #else |
| /* Otherwise, reset that bit so the caller can tell it wasn't |
| acted on. */ |
| advise->is_symglobal = 0; |
| #endif |
| |
| /* And similarly for local only symbol resolution. */ |
| #ifdef RTLD_LOCAL |
| if (advise->is_symlocal) |
| module_flags |= RTLD_LOCAL; |
| #else |
| advise->is_symlocal = 0; |
| #endif |
| } |
| |
| module = dlopen (filename, module_flags); |
| |
| if (!module) |
| { |
| DL__SETERROR (CANNOT_OPEN); |
| } |
| |
| return module; |
| } |
| |
| |
| /* A function called through the vtable when a particular module |
| should be unloaded. */ |
| static int |
| vm_close (lt_user_data LT__UNUSED loader_data, lt_module module) |
| { |
| int errors = 0; |
| |
| if (dlclose (module) != 0) |
| { |
| DL__SETERROR (CANNOT_CLOSE); |
| ++errors; |
| } |
| |
| return errors; |
| } |
| |
| |
| /* A function called through the vtable to get the address of |
| a symbol loaded from a particular module. */ |
| static void * |
| vm_sym (lt_user_data LT__UNUSED loader_data, lt_module module, const char *name) |
| { |
| void *address = dlsym (module, name); |
| |
| if (!address) |
| { |
| DL__SETERROR (SYMBOL_NOT_FOUND); |
| } |
| |
| return address; |
| } |