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- /* vi: set sw=4 ts=4: */
- /*
- * 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>
- #include <stdio.h>
- #if defined (__LIBDL_SHARED__)
- /* When libdl is loaded as a shared library, we need to load in
- * and use a pile of symbols from ldso... */
- extern char *_dl_find_hash(const char *, struct dyn_elf *, int)
- __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__));
- extern int _dl_fixup(struct dyn_elf *rpnt, int lazy)
- __attribute__ ((__weak__));
- extern int _dl_errno __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__));
- #endif
- #ifdef __SUPPORT_LD_DEBUG__
- extern char *_dl_debug __attribute__ ((__weak__));
- #endif
- #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;
- #endif
- char *_dl_library_path = 0; /* Where we look for libraries */
- char *_dl_ldsopath = 0; /* Location of the shared lib loader */
- int _dl_errno = 0; /* We can't use the real errno in ldso */
- size_t _dl_pagesize = PAGE_SIZE; /* Store the page size for use later */
- /* This global variable is also to communicate with debuggers such as gdb. */
- struct r_debug *_dl_debug_addr = NULL;
- #define _dl_malloc malloc
- #include "dl-progname.h"
- #include "../ldso/dl-hash.c"
- #define _dl_trace_loaded_objects 0
- #include "../ldso/dl-elf.c"
- #endif
- static int do_dlclose(void *, int need_fini);
- static const char *dl_error_names[] = {
- "",
- "File not found",
- "Unable to open /dev/zero",
- "Not an ELF file",
- #if defined (__i386__)
- "Not i386 binary",
- #elif defined (__sparc__)
- "Not sparc binary",
- #elif defined (__mc68000__)
- "Not m68k binary",
- #else
- "Unrecognized binary type",
- #endif
- "Not an ELF shared library",
- "Unable to mmap file",
- "No dynamic section",
- #ifdef ELF_USES_RELOCA
- "Unable to process REL relocs",
- #else
- "Unable to process RELA relocs",
- #endif
- "Bad handle",
- "Unable to resolve symbol"
- };
- void __attribute__ ((destructor)) dl_cleanup(void)
- {
- struct dyn_elf *d;
- for (d = _dl_handles; d; d = d->next_handle) {
- do_dlclose(d, 1);
- }
- }
- void *dlopen(const char *libname, int flag)
- {
- struct elf_resolve *tpnt, *tfrom, *tcurr;
- struct dyn_elf *dyn_chain, *rpnt = NULL, *dyn_ptr;
- struct dyn_elf *dpnt;
- ElfW(Addr) from;
- struct elf_resolve *tpnt1;
- void (*dl_brk) (void);
- int now_flag;
- struct init_fini_list *init_list;
- struct init_fini_list *tmp;
- /* A bit of sanity checking... */
- if (!(flag & (RTLD_LAZY|RTLD_NOW))) {
- _dl_error_number = LD_BAD_HANDLE;
- return NULL;
- }
- from = (ElfW(Addr)) __builtin_return_address(0);
- /* Cover the trivial case first */
- if (!libname)
- return _dl_symbol_tables;
- _dl_map_cache();
- /*
- * Try and locate the module we were called from - we
- * need this so that we get the correct RPATH. Note that
- * this is the current behavior under Solaris, but the
- * ABI+ specifies that we should only use the RPATH from
- * the application. Thus this may go away at some time
- * in the future.
- */
- tfrom = NULL;
- for (dpnt = _dl_symbol_tables; dpnt; dpnt = dpnt->next) {
- tpnt = dpnt->dyn;
- if (tpnt->loadaddr < from
- && (tfrom == NULL || tfrom->loadaddr < tpnt->loadaddr))
- tfrom = tpnt;
- }
- for(rpnt = _dl_symbol_tables; rpnt->next; rpnt=rpnt->next);
- /* Try to load the specified library */
- #ifdef __SUPPORT_LD_DEBUG__
- if(_dl_debug)
- fprintf(stderr, "Trying to dlopen '%s'\n", (char*)libname);
- #endif
- tpnt = _dl_check_if_named_library_is_loaded((char *)libname, 0);
- if (!(tpnt))
- tpnt = _dl_load_shared_library(0, &rpnt, tfrom, (char*)libname, 0);
- else
- tpnt->usage_count++;
- if (tpnt == NULL) {
- _dl_unmap_cache();
- return NULL;
- }
- dyn_chain = (struct dyn_elf *) malloc(sizeof(struct dyn_elf));
- _dl_memset(dyn_chain, 0, sizeof(struct dyn_elf));
- dyn_chain->dyn = tpnt;
- tpnt->rtld_flags |= RTLD_GLOBAL;
- dyn_chain->next_handle = _dl_handles;
- _dl_handles = dyn_ptr = dyn_chain;
- #ifdef __SUPPORT_LD_DEBUG__
- if(_dl_debug)
- fprintf(stderr, "Looking for needed libraries\n");
- #endif
- init_list = NULL;
- tmp = malloc(sizeof(struct init_fini_list));
- tmp->tpnt = tpnt;
- tmp->next = NULL;
- tmp->prev = init_list;
- init_list = tmp;
- dyn_chain->init_fini = init_list;
- for (tcurr = tpnt; tcurr; tcurr = tcurr->next)
- {
- Elf32_Dyn *dpnt;
- char *lpntstr;
- for (dpnt = (Elf32_Dyn *) tcurr->dynamic_addr; dpnt->d_tag; dpnt++) {
- if (dpnt->d_tag == DT_NEEDED) {
- char *name;
- lpntstr = (char*) (tcurr->loadaddr + tcurr->dynamic_info[DT_STRTAB] +
- dpnt->d_un.d_val);
- name = _dl_get_last_path_component(lpntstr);
- tpnt1 = _dl_check_if_named_library_is_loaded(name, 0);
- #ifdef __SUPPORT_LD_DEBUG__
- if(_dl_debug)
- fprintf(stderr, "Trying to load '%s', needed by '%s'\n",
- lpntstr, tcurr->libname);
- #endif
- dyn_ptr->next = (struct dyn_elf *) malloc(sizeof(struct dyn_elf));
- _dl_memset (dyn_ptr->next, 0, sizeof (struct dyn_elf));
- dyn_ptr = dyn_ptr->next;
- dyn_ptr->dyn = tpnt1;
- if (!tpnt1) {
- tpnt1 = _dl_load_shared_library(0, &rpnt, tcurr, lpntstr, 0);
- dyn_ptr->dyn = tpnt1;
- if (!tpnt1)
- goto oops;
- tpnt1->rtld_flags |= RTLD_GLOBAL;
- } else {
- tpnt1->rtld_flags |= RTLD_GLOBAL;
- tpnt1->usage_count++;
- }
- tmp = malloc(sizeof(struct init_fini_list));
- tmp->tpnt = tpnt1;
- tmp->next = NULL;
- tmp->prev = init_list;
- init_list->next = tmp;
- init_list = init_list->next;;
- }
- }
- }
- if (dyn_chain->dyn->init_flag & INIT_FUNCS_CALLED) {
- /* If the init and fini stuff has already been run, that means
- * the dlopen'd library has already been loaded, and nothing
- * further needs to be done. */
- return (void *) dyn_chain;
- }
- #ifdef __mips__
- /*
- * Relocation of the GOT entries for MIPS have to be done
- * after all the libraries have been loaded.
- */
- _dl_perform_mips_global_got_relocations(tpnt);
- #endif
- #ifdef __SUPPORT_LD_DEBUG__
- if(_dl_debug)
- fprintf(stderr, "Beginning dlopen relocation fixups\n");
- #endif
- /*
- * OK, now all of the kids are tucked into bed in their proper addresses.
- * Now we go through and look for REL and RELA records that indicate fixups
- * to the GOT tables. We need to do this in reverse order so that COPY
- * directives work correctly */
- now_flag = (flag & RTLD_NOW) ? RTLD_NOW : 0;
- if (getenv("LD_BIND_NOW"))
- now_flag = RTLD_NOW;
- if (_dl_fixup(dyn_chain, now_flag))
- goto oops;
- /* TODO: Should we set the protections of all pages back to R/O now ? */
- /* Notify the debugger we have added some objects. */
- if (_dl_debug_addr) {
- dl_brk = (void (*)(void)) _dl_debug_addr->r_brk;
- if (dl_brk != NULL) {
- _dl_debug_addr->r_state = RT_ADD;
- (*dl_brk) ();
- _dl_debug_addr->r_state = RT_CONSISTENT;
- (*dl_brk) ();
- }
- }
- #if defined (__LIBDL_SHARED__)
- /* Run the ctors and setup the dtors */
- for (; init_list; init_list = init_list->prev) {
- /* Apparently crt1 for the application is responsible for handling this.
- * We only need to run the init/fini for shared libraries. */
- tpnt = init_list->tpnt;
- if (tpnt->init_flag & INIT_FUNCS_CALLED)
- continue;
- tpnt->init_flag |= INIT_FUNCS_CALLED;
- if (tpnt->dynamic_info[DT_INIT]) {
- void (*dl_elf_func) (void);
- 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)
- fprintf(stderr, "running ctors for library %s at '%x'\n", tpnt->libname, dl_elf_func);
- #endif
- (*dl_elf_func) ();
- }
- }
- }
- #endif
- return (void *) dyn_chain;
- oops:
- /* Something went wrong. Clean up and return NULL. */
- _dl_unmap_cache();
- do_dlclose(dyn_chain, 0);
- return NULL;
- }
- void *dlsym(void *vhandle, const char *name)
- {
- struct elf_resolve *tpnt, *tfrom;
- struct dyn_elf *handle;
- ElfW(Addr) from;
- struct dyn_elf *rpnt;
- void *ret;
- handle = (struct dyn_elf *) vhandle;
- /* First of all verify that we have a real handle
- of some kind. Return NULL if not a valid handle. */
- if (handle == NULL)
- handle = _dl_symbol_tables;
- else if (handle != RTLD_NEXT && handle != _dl_symbol_tables) {
- for (rpnt = _dl_handles; rpnt; rpnt = rpnt->next_handle)
- if (rpnt == handle)
- break;
- if (!rpnt) {
- _dl_error_number = LD_BAD_HANDLE;
- return NULL;
- }
- } else if (handle == RTLD_NEXT) {
- /*
- * Try and locate the module we were called from - we
- * need this so that we know where to start searching
- * from. We never pass RTLD_NEXT down into the actual
- * dynamic loader itself, as it doesn't know
- * how to properly treat it.
- */
- from = (ElfW(Addr)) __builtin_return_address(0);
- tfrom = NULL;
- for (rpnt = _dl_symbol_tables; rpnt; rpnt = rpnt->next) {
- tpnt = rpnt->dyn;
- if (tpnt->loadaddr < from
- && (tfrom == NULL || tfrom->loadaddr < tpnt->loadaddr)) {
- tfrom = tpnt;
- handle = rpnt->next;
- }
- }
- }
- ret = _dl_find_hash((char*)name, handle, 0);
- /*
- * Nothing found.
- */
- if (!ret)
- _dl_error_number = LD_NO_SYMBOL;
- return ret;
- }
- static int do_dlclose(void *vhandle, int need_fini)
- {
- struct dyn_elf *rpnt, *rpnt1;
- ElfW(Phdr) *ppnt;
- struct elf_resolve *tpnt;
- int (*dl_elf_fini) (void);
- void (*dl_brk) (void);
- struct dyn_elf *handle;
- unsigned int end;
- int i = 0;
- struct init_fini_list *fini_list, *tmp;
- handle = (struct dyn_elf *) vhandle;
- rpnt1 = NULL;
- for (rpnt = _dl_handles; rpnt; rpnt = rpnt->next_handle) {
- if (rpnt == handle)
- break;
- rpnt1 = rpnt;
- }
- if (!rpnt) {
- _dl_error_number = LD_BAD_HANDLE;
- return 1;
- }
- if (rpnt1)
- rpnt1->next_handle = rpnt->next_handle;
- else
- _dl_handles = rpnt->next_handle;
- if (need_fini) {
- for (fini_list = handle->init_fini; fini_list; ) {
- tpnt = fini_list->tpnt;
- tmp = NULL;
- if (tpnt->dynamic_info[DT_FINI] && tpnt->usage_count == 1 &&
- !(tpnt->init_flag & FINI_FUNCS_CALLED)) {
- tpnt->init_flag |= FINI_FUNCS_CALLED;
- dl_elf_fini = (int (*)(void)) (tpnt->loadaddr + tpnt->dynamic_info[DT_FINI]);
- #ifdef __SUPPORT_LD_DEBUG__
- if(_dl_debug)
- fprintf(stderr, "running dtors for library %s at '%x'\n", tpnt->libname, dl_elf_fini);
- #endif
- (*dl_elf_fini) ();
- tmp = fini_list;
- }
- fini_list = fini_list->next;
- free(tmp);
- }
- }
- /* OK, this is a valid handle - now close out the file */
- for (rpnt = handle; rpnt; rpnt = rpnt->next) {
- tpnt = rpnt->dyn;
- if (--tpnt->usage_count == 0) {
- end = 0;
- for (i = 0, ppnt = tpnt->ppnt;
- i < tpnt->n_phent; ppnt++, i++) {
- if (ppnt->p_type != PT_LOAD)
- continue;
- if (end < ppnt->p_vaddr + ppnt->p_memsz)
- end = ppnt->p_vaddr + ppnt->p_memsz;
- }
- _dl_munmap((void*)tpnt->loadaddr, end);
- /* Next, remove tpnt from the loaded_module list */
- if (_dl_loaded_modules == tpnt) {
- _dl_loaded_modules = tpnt->next;
- if (_dl_loaded_modules)
- _dl_loaded_modules->prev = 0;
- } else
- for (tpnt = _dl_loaded_modules; tpnt; tpnt = tpnt->next)
- if (tpnt->next == rpnt->dyn) {
- tpnt->next = tpnt->next->next;
- if (tpnt->next)
- tpnt->next->prev = tpnt;
- break;
- }
- /* Next, remove tpnt from the global symbol table list */
- if (_dl_symbol_tables->dyn == rpnt->dyn) {
- _dl_symbol_tables = rpnt->next;
- if (_dl_symbol_tables)
- _dl_symbol_tables->prev = 0;
- } else
- for (rpnt1 = _dl_symbol_tables; rpnt1->next; rpnt1 = rpnt1->next) {
- if (rpnt1->next->dyn == rpnt->dyn) {
- free(rpnt1->next);
- rpnt1->next = rpnt1->next->next;
- if (rpnt1->next)
- rpnt1->next->prev = rpnt1;
- break;
- }
- }
- free(rpnt->dyn->libname);
- free(rpnt->dyn);
- }
- free(rpnt);
- }
- if (_dl_debug_addr) {
- dl_brk = (void (*)(void)) _dl_debug_addr->r_brk;
- if (dl_brk != NULL) {
- _dl_debug_addr->r_state = RT_DELETE;
- (*dl_brk) ();
- _dl_debug_addr->r_state = RT_CONSISTENT;
- (*dl_brk) ();
- }
- }
- return 0;
- }
- int dlclose(void *vhandle)
- {
- return do_dlclose(vhandle, 1);
- }
- const char *dlerror(void)
- {
- const char *retval;
- if (!_dl_error_number)
- return NULL;
- retval = dl_error_names[_dl_error_number];
- _dl_error_number = 0;
- return retval;
- }
- /*
- * Dump information to stderrr about the current loaded modules
- */
- static char *type[] = { "Lib", "Exe", "Int", "Mod" };
- void dlinfo(void)
- {
- struct elf_resolve *tpnt;
- struct dyn_elf *rpnt, *hpnt;
- fprintf(stderr, "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) {
- fprintf(stderr, "\t%x %x %x %s %d %s\n",
- (unsigned) tpnt->loadaddr, (unsigned) tpnt,
- (unsigned) tpnt->symbol_scope,
- type[tpnt->libtype],
- tpnt->usage_count, tpnt->libname);
- }
- /* Next dump the module list for the application itself */
- fprintf(stderr, "\nModules for application (%x):\n",
- (unsigned) _dl_symbol_tables);
- for (rpnt = _dl_symbol_tables; rpnt; rpnt = rpnt->next)
- fprintf(stderr, "\t%x %s\n", (unsigned) rpnt->dyn, rpnt->dyn->libname);
- for (hpnt = _dl_handles; hpnt; hpnt = hpnt->next_handle) {
- fprintf(stderr, "Modules for handle %x\n", (unsigned) hpnt);
- for (rpnt = hpnt; rpnt; rpnt = rpnt->next)
- fprintf(stderr, "\t%x %s\n", (unsigned) rpnt->dyn,
- rpnt->dyn->libname);
- }
- }
- int dladdr(const void *__address, Dl_info * __info)
- {
- struct elf_resolve *pelf;
- struct elf_resolve *rpnt;
- _dl_map_cache();
- /*
- * Try and locate the module address is in
- */
- pelf = NULL;
- #if 0
- fprintf(stderr, "dladdr( %x, %x )\n", __address, __info);
- #endif
- for (rpnt = _dl_loaded_modules; rpnt; rpnt = rpnt->next) {
- struct elf_resolve *tpnt;
- tpnt = rpnt;
- #if 0
- fprintf(stderr, "Module \"%s\" at %x\n",
- tpnt->libname, tpnt->loadaddr);
- #endif
- if (tpnt->loadaddr < (ElfW(Addr)) __address
- && (pelf == NULL || pelf->loadaddr < tpnt->loadaddr)) {
- pelf = tpnt;
- }
- }
- if (!pelf) {
- return 0;
- }
- /*
- * Try and locate the symbol of address
- */
- {
- char *strtab;
- Elf32_Sym *symtab;
- int hn, si;
- int sf;
- int sn = 0;
- ElfW(Addr) sa;
- sa = 0;
- symtab = (Elf32_Sym *) (pelf->dynamic_info[DT_SYMTAB] + pelf->loadaddr);
- strtab = (char *) (pelf->dynamic_info[DT_STRTAB] + pelf->loadaddr);
- sf = 0;
- for (hn = 0; hn < pelf->nbucket; hn++) {
- for (si = pelf->elf_buckets[hn]; si; si = pelf->chains[si]) {
- ElfW(Addr) symbol_addr;
- symbol_addr = pelf->loadaddr + symtab[si].st_value;
- if (symbol_addr <= (ElfW(Addr))__address && (!sf || sa < symbol_addr)) {
- sa = symbol_addr;
- sn = si;
- sf = 1;
- }
- #if 0
- fprintf(stderr, "Symbol \"%s\" at %x\n",
- strtab + symtab[si].st_name, symbol_addr);
- #endif
- }
- }
- if (sf) {
- __info->dli_fname = pelf->libname;
- __info->dli_fbase = (void *)pelf->loadaddr;
- __info->dli_sname = strtab + symtab[sn].st_name;
- __info->dli_saddr = (void *)sa;
- }
- return 1;
- }
- }
|