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Diffstat (limited to 'libltdl/loaders/dlopen.c')
| -rw-r--r-- | libltdl/loaders/dlopen.c | 242 |
1 files changed, 242 insertions, 0 deletions
diff --git a/libltdl/loaders/dlopen.c b/libltdl/loaders/dlopen.c new file mode 100644 index 0000000..b445407 --- /dev/null +++ b/libltdl/loaders/dlopen.c @@ -0,0 +1,242 @@ +/* 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 + } + + /* On AIX, dlopen(NULL) succeeds but dlsym of symbols fails. + In this case, fail here to let the preopen loader do the job. */ +#ifndef LTDL_DLOPEN_SELF_WORKS + if (!filename) + module = NULL; + else +#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; +} |