diff options
| -rw-r--r-- | ldso/libdl/libdl.c | 174 |
1 files changed, 96 insertions, 78 deletions
diff --git a/ldso/libdl/libdl.c b/ldso/libdl/libdl.c index 5d7c22b85..9191f99cf 100644 --- a/ldso/libdl/libdl.c +++ b/ldso/libdl/libdl.c @@ -1,70 +1,82 @@ +/* vi: set sw=4 ts=4: */ /* - * libdl.c - * - * Functions required for dlopen et. al. + * Program to load an ELF binary on a linux system, and run it + * after resolving ELF shared library symbols + * + * Copyright (C) 2000-2004 by Erik Andersen <andersen@codpoet.org> + * Copyright (c) 1994-2000 Eric Youngdale, Peter MacDonald, + * David Engel, Hongjiu Lu and Mitch D'Souza + * + * 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. The name of the above contributors may not be + * used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS ``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 CONTRIBUTORS 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 <ldso.h> - -/* The public interfaces */ -void *dlopen(const char *, int) __attribute__ ((__weak__, __alias__ ("_dlopen"))); -int dlclose(void *) __attribute__ ((__weak__, __alias__ ("_dlclose"))); -void *dlsym(void *, const char *) __attribute__ ((__weak__, __alias__ ("_dlsym"))); -const char *dlerror(void) __attribute__ ((__weak__, __alias__ ("_dlerror"))); -int dladdr(void *, Dl_info *) __attribute__ ((__weak__, __alias__ ("_dladdr"))); -void _dlinfo(void); +#include <ldso.h> #if defined (__LIBDL_SHARED__) -/* This is a real hack. We need access to the dynamic linker, but we -also need to make it possible to link against this library without any -unresolved externals. We provide these weak symbols to make the link -possible, but at run time the normal symbols are accessed. */ -static void __attribute__ ((unused)) foobar(void) -{ - const char msg[]="libdl library not correctly linked\n"; - _dl_write(2, msg, _dl_strlen(msg)); - _dl_exit(1); -} -static int __attribute__ ((unused)) foobar1 = (int) foobar; /* Use as pointer */ -extern void _dl_dprintf(int, const char *, ...) __attribute__ ((__weak__, __alias__ ("foobar"))); +/* When libdl is loaded as a shared library, we need to load in + * and use a pile of symbols from ldso... */ + +extern void _dl_dprintf(int, const char *, ...) __attribute__ ((__weak__)); extern char *_dl_find_hash(const char *, struct dyn_elf *, int) - __attribute__ ((__weak__, __alias__ ("foobar"))); -extern struct elf_resolve * _dl_load_shared_library(int, struct dyn_elf **, struct elf_resolve *, char *, int) - __attribute__ ((__weak__, __alias__ ("foobar"))); + __attribute__ ((__weak__)); +extern struct elf_resolve * _dl_load_shared_library(int, struct dyn_elf **, + struct elf_resolve *, char *, int) __attribute__ ((__weak__)); extern struct elf_resolve * _dl_check_if_named_library_is_loaded(const char *, int) - __attribute__ ((__weak__, __alias__ ("foobar"))); + __attribute__ ((__weak__)); extern int _dl_fixup(struct dyn_elf *rpnt, int lazy) - __attribute__ ((__weak__, __alias__ ("foobar"))); + __attribute__ ((__weak__)); +extern struct dyn_elf *_dl_symbol_tables __attribute__ ((__weak__)); +extern struct dyn_elf *_dl_handles __attribute__ ((__weak__)); +extern struct elf_resolve *_dl_loaded_modules __attribute__ ((__weak__)); +extern struct r_debug *_dl_debug_addr __attribute__ ((__weak__)); +extern unsigned long _dl_error_number __attribute__ ((__weak__)); +extern void *(*_dl_malloc_function)(size_t) __attribute__ ((__weak__)); +#ifdef USE_CACHE +int _dl_map_cache(void) __attribute__ ((__weak__)); +int _dl_unmap_cache(void) __attribute__ ((__weak__)); +#endif #ifdef __mips__ extern void _dl_perform_mips_global_got_relocations(struct elf_resolve *tpnt) - __attribute__ ((__weak__, __alias__ ("foobar"))); + __attribute__ ((__weak__)); #endif -#ifdef USE_CACHE -int _dl_map_cache(void) __attribute__ ((__weak__, __alias__ ("foobar"))); -int _dl_unmap_cache(void) __attribute__ ((__weak__, __alias__ ("foobar"))); -#endif - -extern struct dyn_elf *_dl_symbol_tables __attribute__ ((__weak__, __alias__ ("foobar1"))); -extern struct dyn_elf *_dl_handles __attribute__ ((__weak__, __alias__ ("foobar1"))); -extern struct elf_resolve *_dl_loaded_modules __attribute__ ((__weak__, __alias__ ("foobar1"))); -extern struct r_debug *_dl_debug_addr __attribute__ ((__weak__, __alias__ ("foobar1"))); -extern unsigned long _dl_error_number __attribute__ ((__weak__, __alias__ ("foobar1"))); -extern void *(*_dl_malloc_function)(size_t) __attribute__ ((__weak__, __alias__ ("foobar1"))); #ifdef __SUPPORT_LD_DEBUG__ -extern char *_dl_debug __attribute__ ((__weak__, __alias__ ("foobar1"))); -extern char *_dl_debug_symbols __attribute__ ((__weak__, __alias__ ("foobar1"))); -extern char *_dl_debug_move __attribute__ ((__weak__, __alias__ ("foobar1"))); -extern char *_dl_debug_reloc __attribute__ ((__weak__, __alias__ ("foobar1"))); -extern char *_dl_debug_detail __attribute__ ((__weak__, __alias__ ("foobar1"))); -extern char *_dl_debug_nofixups __attribute__ ((__weak__, __alias__ ("foobar1"))); -extern char *_dl_debug_bindings __attribute__ ((__weak__, __alias__ ("foobar1"))); -extern int _dl_debug_file __attribute__ ((__weak__, __alias__ ("foobar1"))); +extern char *_dl_debug __attribute__ ((__weak__)); +extern char *_dl_debug_symbols __attribute__ ((__weak__)); +extern char *_dl_debug_move __attribute__ ((__weak__)); +extern char *_dl_debug_reloc __attribute__ ((__weak__)); +extern char *_dl_debug_detail __attribute__ ((__weak__)); +extern char *_dl_debug_nofixups __attribute__ ((__weak__)); +extern char *_dl_debug_bindings __attribute__ ((__weak__)); +extern int _dl_debug_file __attribute__ ((__weak__)); #endif -#else /* __LIBDL_SHARED__ */ + +#else /* __LIBDL_SHARED__ */ + +/* When libdl is linked as a static library, we need to replace all + * the symbols that otherwise would have been loaded in from ldso... */ #ifdef __SUPPORT_LD_DEBUG__ char *_dl_debug = 0; @@ -80,12 +92,12 @@ char *_dl_library_path = 0; char *_dl_ldsopath = 0; struct r_debug *_dl_debug_addr = NULL; static unsigned char *_dl_malloc_addr, *_dl_mmap_zero; +void *(*_dl_malloc_function) (size_t size); +int _dl_fixup(struct dyn_elf *rpnt, int lazy); #include "../ldso/dl-progname.h" /* Pull in the name of ld.so */ #include "../ldso/dl-hash.c" #define _dl_trace_loaded_objects 0 #include "../ldso/dl-elf.c" -void *(*_dl_malloc_function) (size_t size); -int _dl_fixup(struct dyn_elf *rpnt, int lazy); #endif static int do_dlclose(void *, int need_fini); @@ -176,7 +188,7 @@ void *_dlopen(const char *libname, int flag) /* Try to load the specified library */ #ifdef __SUPPORT_LD_DEBUG__ - if(_dl_debug) + if(_dl_debug) _dl_dprintf(_dl_debug_file, "Trying to dlopen '%s'\n", (char*)libname); #endif if (!(tpnt = _dl_check_if_named_library_is_loaded((char *)libname, 0))) @@ -205,7 +217,7 @@ void *_dlopen(const char *libname, int flag) #ifdef __SUPPORT_LD_DEBUG__ - if(_dl_debug) + if(_dl_debug) _dl_dprintf(_dl_debug_file, "Looking for needed libraries\n"); #endif @@ -217,7 +229,7 @@ void *_dlopen(const char *libname, int flag) if (dpnt->d_tag == DT_NEEDED) { char *name; - lpntstr = (char*) (tcurr->loadaddr + tcurr->dynamic_info[DT_STRTAB] + + lpntstr = (char*) (tcurr->loadaddr + tcurr->dynamic_info[DT_STRTAB] + dpnt->d_un.d_val); name = _dl_get_last_path_component(lpntstr); @@ -225,8 +237,8 @@ void *_dlopen(const char *libname, int flag) continue; #ifdef __SUPPORT_LD_DEBUG__ - if(_dl_debug) - _dl_dprintf(_dl_debug_file, "Trying to load '%s', needed by '%s'\n", + if(_dl_debug) + _dl_dprintf(_dl_debug_file, "Trying to load '%s', needed by '%s'\n", lpntstr, tcurr->libname); #endif @@ -258,7 +270,7 @@ void *_dlopen(const char *libname, int flag) #endif #ifdef __SUPPORT_LD_DEBUG__ - if(_dl_debug) + if(_dl_debug) _dl_dprintf(_dl_debug_file, "Beginning dlopen relocation fixups\n"); #endif /* @@ -285,7 +297,7 @@ void *_dlopen(const char *libname, int flag) } #if 0 //def __SUPPORT_LD_DEBUG__ - if(_dl_debug) + if(_dl_debug) _dlinfo(); #endif @@ -313,7 +325,7 @@ void *_dlopen(const char *libname, int flag) dl_elf_func = (void (*)(void)) (tpnt->loadaddr + tpnt->dynamic_info[DT_INIT]); if (dl_elf_func && *dl_elf_func != NULL) { #ifdef __SUPPORT_LD_DEBUG__ - if(_dl_debug) + if(_dl_debug) _dl_dprintf(2, "running ctors for library %s at '%x'\n", tpnt->libname, dl_elf_func); #endif (*dl_elf_func) (); @@ -324,7 +336,7 @@ void *_dlopen(const char *libname, int flag) dl_elf_func = (void (*)(void)) (tpnt->loadaddr + tpnt->dynamic_info[DT_FINI]); if (dl_elf_func && *dl_elf_func != NULL) { #ifdef __SUPPORT_LD_DEBUG__ - if(_dl_debug) + if(_dl_debug) _dl_dprintf(2, "setting up dtors for library %s at '%x'\n", tpnt->libname, dl_elf_func); #endif atexit(dl_elf_func); @@ -340,6 +352,7 @@ oops: do_dlclose(dyn_chain, 0); return NULL; } +weak_alias(_dlopen, dlopen); void *_dlsym(void *vhandle, const char *name) { @@ -394,11 +407,7 @@ void *_dlsym(void *vhandle, const char *name) _dl_error_number = LD_NO_SYMBOL; return ret; } - -int _dlclose(void *vhandle) -{ - return do_dlclose(vhandle, 1); -} +weak_alias(_dlsym, dlsym); static int do_dlclose(void *vhandle, int need_fini) { @@ -432,7 +441,7 @@ static int do_dlclose(void *vhandle, int need_fini) for (; spnt; spnt = spnt1) { spnt1 = spnt->next; - /* We appended the module list to the end - when we get back here, + /* We appended the module list to the end - when we get back here, quit. The access counts were not adjusted to account for being here. */ if (spnt == _dl_symbol_tables) break; @@ -444,7 +453,7 @@ static int do_dlclose(void *vhandle, int need_fini) */ if (tpnt->dynamic_info[DT_FINI]) { - dl_elf_fini = (int (*)(void)) (tpnt->loadaddr + + dl_elf_fini = (int (*)(void)) (tpnt->loadaddr + tpnt->dynamic_info[DT_FINI]); (*dl_elf_fini) (); } @@ -459,7 +468,7 @@ static int do_dlclose(void *vhandle, int need_fini) for (rpnt = handle; rpnt; rpnt = rpnt1) { rpnt1 = rpnt->next; - /* We appended the module list to the end - when we get back here, + /* We appended the module list to the end - when we get back here, quit. The access counts were not adjusted to account for being here. */ if (rpnt == _dl_symbol_tables) break; @@ -473,10 +482,10 @@ static int do_dlclose(void *vhandle, int need_fini) */ #if 0 - /* We have to do this above, before we start closing objects. - * Otherwise when the needed symbols for _fini handling are - * resolved a coredump would occur. Rob Ryan (robr@cmu.edu)*/ - if (tpnt->dynamic_info[DT_FINI]) { + /* We have to do this above, before we start closing objects. + * Otherwise when the needed symbols for _fini handling are + * resolved a coredump would occur. Rob Ryan (robr@cmu.edu)*/ + if (tpnt->dynamic_info[DT_FINI]) { dl_elf_fini = (int (*)(void)) (tpnt->loadaddr + tpnt->dynamic_info[DT_FINI]); (*dl_elf_fini) (); } @@ -524,6 +533,12 @@ static int do_dlclose(void *vhandle, int need_fini) return 0; } +int _dlclose(void *vhandle) +{ + return do_dlclose(vhandle, 1); +} +weak_alias(_dlclose, dlclose); + const char *_dlerror(void) { const char *retval; @@ -534,6 +549,7 @@ const char *_dlerror(void) _dl_error_number = 0; return retval; } +weak_alias(_dlerror, dlerror); /* * Dump information to stderrr about the current loaded modules @@ -547,8 +563,8 @@ void _dlinfo(void) _dl_dprintf(2, "List of loaded modules\n"); /* First start with a complete list of all of the loaded files. */ - for (tpnt = _dl_loaded_modules; tpnt; tpnt = tpnt->next) { - _dl_dprintf(2, "\t%x %x %x %s %d %s\n", + for (tpnt = _dl_loaded_modules; tpnt; tpnt = tpnt->next) { + _dl_dprintf(2, "\t%x %x %x %s %d %s\n", (unsigned) tpnt->loadaddr, (unsigned) tpnt, (unsigned) tpnt->symbol_scope, type[tpnt->libtype], @@ -564,10 +580,11 @@ void _dlinfo(void) for (hpnt = _dl_handles; hpnt; hpnt = hpnt->next_handle) { _dl_dprintf(2, "Modules for handle %x\n", (unsigned) hpnt); for (rpnt = hpnt; rpnt; rpnt = rpnt->next) - _dl_dprintf(2, "\t%x %s\n", (unsigned) rpnt->dyn, + _dl_dprintf(2, "\t%x %s\n", (unsigned) rpnt->dyn, rpnt->dyn->libname); } } +weak_alias(_dlinfo, dlinfo); int _dladdr(void *__address, Dl_info * __dlip) { @@ -590,7 +607,7 @@ int _dladdr(void *__address, Dl_info * __dlip) tpnt = rpnt; #if 0 - _dl_dprintf(2, "Module \"%s\" at %x\n", + _dl_dprintf(2, "Module \"%s\" at %x\n", tpnt->libname, tpnt->loadaddr); #endif if (tpnt->loadaddr < (ElfW(Addr)) __address @@ -631,7 +648,7 @@ int _dladdr(void *__address, Dl_info * __dlip) sf = 1; } #if 0 - _dl_dprintf(2, "Symbol \"%s\" at %x\n", + _dl_dprintf(2, "Symbol \"%s\" at %x\n", strtab + symtab[si].st_name, symbol_addr); #endif } @@ -646,3 +663,4 @@ int _dladdr(void *__address, Dl_info * __dlip) return 1; } } +weak_alias(_dladdr, dladdr); |