diff options
Diffstat (limited to 'elf/dl-open.c')
| -rw-r--r-- | elf/dl-open.c | 737 |
1 files changed, 0 insertions, 737 deletions
diff --git a/elf/dl-open.c b/elf/dl-open.c deleted file mode 100644 index cec54db413..0000000000 --- a/elf/dl-open.c +++ /dev/null @@ -1,737 +0,0 @@ -/* Load a shared object at runtime, relocate it, and run its initializer. - Copyright (C) 1996-2017 Free Software Foundation, Inc. - This file is part of the GNU C Library. - - The GNU C Library 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 2.1 of the License, or (at your option) any later version. - - The GNU C Library 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 the GNU C Library; if not, see - <http://www.gnu.org/licenses/>. */ - -#include <assert.h> -#include <dlfcn.h> -#include <errno.h> -#include <libintl.h> -#include <stdio.h> -#include <stdlib.h> -#include <string.h> -#include <unistd.h> -#include <sys/mman.h> /* Check whether MAP_COPY is defined. */ -#include <sys/param.h> -#include <libc-lock.h> -#include <ldsodefs.h> -#include <caller.h> -#include <sysdep-cancel.h> -#include <tls.h> -#include <stap-probe.h> -#include <atomic.h> - -#include <dl-dst.h> - - -extern int __libc_multiple_libcs; /* Defined in init-first.c. */ - -/* We must be careful not to leave us in an inconsistent state. Thus we - catch any error and re-raise it after cleaning up. */ - -struct dl_open_args -{ - const char *file; - int mode; - /* This is the caller of the dlopen() function. */ - const void *caller_dlopen; - /* This is the caller of _dl_open(). */ - const void *caller_dl_open; - struct link_map *map; - /* Namespace ID. */ - Lmid_t nsid; - /* Original parameters to the program and the current environment. */ - int argc; - char **argv; - char **env; -}; - - -static int -add_to_global (struct link_map *new) -{ - struct link_map **new_global; - unsigned int to_add = 0; - unsigned int cnt; - - /* Count the objects we have to put in the global scope. */ - for (cnt = 0; cnt < new->l_searchlist.r_nlist; ++cnt) - if (new->l_searchlist.r_list[cnt]->l_global == 0) - ++to_add; - - /* The symbols of the new objects and its dependencies are to be - introduced into the global scope that will be used to resolve - references from other dynamically-loaded objects. - - The global scope is the searchlist in the main link map. We - extend this list if necessary. There is one problem though: - since this structure was allocated very early (before the libc - is loaded) the memory it uses is allocated by the malloc()-stub - in the ld.so. When we come here these functions are not used - anymore. Instead the malloc() implementation of the libc is - used. But this means the block from the main map cannot be used - in an realloc() call. Therefore we allocate a completely new - array the first time we have to add something to the locale scope. */ - - struct link_namespaces *ns = &GL(dl_ns)[new->l_ns]; - if (ns->_ns_global_scope_alloc == 0) - { - /* This is the first dynamic object given global scope. */ - ns->_ns_global_scope_alloc - = ns->_ns_main_searchlist->r_nlist + to_add + 8; - new_global = (struct link_map **) - malloc (ns->_ns_global_scope_alloc * sizeof (struct link_map *)); - if (new_global == NULL) - { - ns->_ns_global_scope_alloc = 0; - nomem: - _dl_signal_error (ENOMEM, new->l_libname->name, NULL, - N_("cannot extend global scope")); - return 1; - } - - /* Copy over the old entries. */ - ns->_ns_main_searchlist->r_list - = memcpy (new_global, ns->_ns_main_searchlist->r_list, - (ns->_ns_main_searchlist->r_nlist - * sizeof (struct link_map *))); - } - else if (ns->_ns_main_searchlist->r_nlist + to_add - > ns->_ns_global_scope_alloc) - { - /* We have to extend the existing array of link maps in the - main map. */ - struct link_map **old_global - = GL(dl_ns)[new->l_ns]._ns_main_searchlist->r_list; - size_t new_nalloc = ((ns->_ns_global_scope_alloc + to_add) * 2); - - new_global = (struct link_map **) - malloc (new_nalloc * sizeof (struct link_map *)); - if (new_global == NULL) - goto nomem; - - memcpy (new_global, old_global, - ns->_ns_global_scope_alloc * sizeof (struct link_map *)); - - ns->_ns_global_scope_alloc = new_nalloc; - ns->_ns_main_searchlist->r_list = new_global; - - if (!RTLD_SINGLE_THREAD_P) - THREAD_GSCOPE_WAIT (); - - free (old_global); - } - - /* Now add the new entries. */ - unsigned int new_nlist = ns->_ns_main_searchlist->r_nlist; - for (cnt = 0; cnt < new->l_searchlist.r_nlist; ++cnt) - { - struct link_map *map = new->l_searchlist.r_list[cnt]; - - if (map->l_global == 0) - { - map->l_global = 1; - ns->_ns_main_searchlist->r_list[new_nlist++] = map; - - /* We modify the global scope. Report this. */ - if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_SCOPES)) - _dl_debug_printf ("\nadd %s [%lu] to global scope\n", - map->l_name, map->l_ns); - } - } - atomic_write_barrier (); - ns->_ns_main_searchlist->r_nlist = new_nlist; - - return 0; -} - -/* Search link maps in all namespaces for the DSO that contains the object at - address ADDR. Returns the pointer to the link map of the matching DSO, or - NULL if a match is not found. */ -struct link_map * -internal_function -_dl_find_dso_for_object (const ElfW(Addr) addr) -{ - struct link_map *l; - - /* Find the highest-addressed object that ADDR is not below. */ - for (Lmid_t ns = 0; ns < GL(dl_nns); ++ns) - for (l = GL(dl_ns)[ns]._ns_loaded; l != NULL; l = l->l_next) - if (addr >= l->l_map_start && addr < l->l_map_end - && (l->l_contiguous - || _dl_addr_inside_object (l, (ElfW(Addr)) addr))) - { - assert (ns == l->l_ns); - return l; - } - return NULL; -} -rtld_hidden_def (_dl_find_dso_for_object); - -static void -dl_open_worker (void *a) -{ - struct dl_open_args *args = a; - const char *file = args->file; - int mode = args->mode; - struct link_map *call_map = NULL; - - /* Check whether _dl_open() has been called from a valid DSO. */ - if (__check_caller (args->caller_dl_open, - allow_libc|allow_libdl|allow_ldso) != 0) - _dl_signal_error (0, "dlopen", NULL, N_("invalid caller")); - - /* Determine the caller's map if necessary. This is needed in case - we have a DST, when we don't know the namespace ID we have to put - the new object in, or when the file name has no path in which - case we need to look along the RUNPATH/RPATH of the caller. */ - const char *dst = strchr (file, '$'); - if (dst != NULL || args->nsid == __LM_ID_CALLER - || strchr (file, '/') == NULL) - { - const void *caller_dlopen = args->caller_dlopen; - - /* We have to find out from which object the caller is calling. - By default we assume this is the main application. */ - call_map = GL(dl_ns)[LM_ID_BASE]._ns_loaded; - - struct link_map *l = _dl_find_dso_for_object ((ElfW(Addr)) caller_dlopen); - - if (l) - call_map = l; - - if (args->nsid == __LM_ID_CALLER) - args->nsid = call_map->l_ns; - } - - /* One might be tempted to assert that we are RT_CONSISTENT at this point, but that - may not be true if this is a recursive call to dlopen. */ - _dl_debug_initialize (0, args->nsid); - - /* Load the named object. */ - struct link_map *new; - args->map = new = _dl_map_object (call_map, file, lt_loaded, 0, - mode | __RTLD_CALLMAP, args->nsid); - - /* If the pointer returned is NULL this means the RTLD_NOLOAD flag is - set and the object is not already loaded. */ - if (new == NULL) - { - assert (mode & RTLD_NOLOAD); - return; - } - - /* Mark the object as not deletable if the RTLD_NODELETE flags was passed. - Do this early so that we don't skip marking the object if it was - already loaded. */ - if (__glibc_unlikely (mode & RTLD_NODELETE)) - new->l_flags_1 |= DF_1_NODELETE; - - if (__glibc_unlikely (mode & __RTLD_SPROF)) - /* This happens only if we load a DSO for 'sprof'. */ - return; - - /* This object is directly loaded. */ - ++new->l_direct_opencount; - - /* It was already open. */ - if (__glibc_unlikely (new->l_searchlist.r_list != NULL)) - { - /* Let the user know about the opencount. */ - if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_FILES)) - _dl_debug_printf ("opening file=%s [%lu]; direct_opencount=%u\n\n", - new->l_name, new->l_ns, new->l_direct_opencount); - - /* If the user requested the object to be in the global namespace - but it is not so far, add it now. */ - if ((mode & RTLD_GLOBAL) && new->l_global == 0) - (void) add_to_global (new); - - assert (_dl_debug_initialize (0, args->nsid)->r_state == RT_CONSISTENT); - - return; - } - - /* Load that object's dependencies. */ - _dl_map_object_deps (new, NULL, 0, 0, - mode & (__RTLD_DLOPEN | RTLD_DEEPBIND | __RTLD_AUDIT)); - - /* So far, so good. Now check the versions. */ - for (unsigned int i = 0; i < new->l_searchlist.r_nlist; ++i) - if (new->l_searchlist.r_list[i]->l_real->l_versions == NULL) - (void) _dl_check_map_versions (new->l_searchlist.r_list[i]->l_real, - 0, 0); - -#ifdef SHARED - /* Auditing checkpoint: we have added all objects. */ - if (__glibc_unlikely (GLRO(dl_naudit) > 0)) - { - struct link_map *head = GL(dl_ns)[new->l_ns]._ns_loaded; - /* Do not call the functions for any auditing object. */ - if (head->l_auditing == 0) - { - struct audit_ifaces *afct = GLRO(dl_audit); - for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt) - { - if (afct->activity != NULL) - afct->activity (&head->l_audit[cnt].cookie, LA_ACT_CONSISTENT); - - afct = afct->next; - } - } - } -#endif - - /* Notify the debugger all new objects are now ready to go. */ - struct r_debug *r = _dl_debug_initialize (0, args->nsid); - r->r_state = RT_CONSISTENT; - _dl_debug_state (); - LIBC_PROBE (map_complete, 3, args->nsid, r, new); - - /* Print scope information. */ - if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_SCOPES)) - _dl_show_scope (new, 0); - - /* Only do lazy relocation if `LD_BIND_NOW' is not set. */ - int reloc_mode = mode & __RTLD_AUDIT; - if (GLRO(dl_lazy)) - reloc_mode |= mode & RTLD_LAZY; - - /* Sort the objects by dependency for the relocation process. This - allows IFUNC relocations to work and it also means copy - relocation of dependencies are if necessary overwritten. */ - size_t nmaps = 0; - struct link_map *l = new; - do - { - if (! l->l_real->l_relocated) - ++nmaps; - l = l->l_next; - } - while (l != NULL); - struct link_map *maps[nmaps]; - nmaps = 0; - l = new; - do - { - if (! l->l_real->l_relocated) - maps[nmaps++] = l; - l = l->l_next; - } - while (l != NULL); - if (nmaps > 1) - { - uint16_t seen[nmaps]; - memset (seen, '\0', sizeof (seen)); - size_t i = 0; - while (1) - { - ++seen[i]; - struct link_map *thisp = maps[i]; - - /* Find the last object in the list for which the current one is - a dependency and move the current object behind the object - with the dependency. */ - size_t k = nmaps - 1; - while (k > i) - { - struct link_map **runp = maps[k]->l_initfini; - if (runp != NULL) - /* Look through the dependencies of the object. */ - while (*runp != NULL) - if (__glibc_unlikely (*runp++ == thisp)) - { - /* Move the current object to the back past the last - object with it as the dependency. */ - memmove (&maps[i], &maps[i + 1], - (k - i) * sizeof (maps[0])); - maps[k] = thisp; - - if (seen[i + 1] > nmaps - i) - { - ++i; - goto next_clear; - } - - uint16_t this_seen = seen[i]; - memmove (&seen[i], &seen[i + 1], - (k - i) * sizeof (seen[0])); - seen[k] = this_seen; - - goto next; - } - - --k; - } - - if (++i == nmaps) - break; - next_clear: - memset (&seen[i], 0, (nmaps - i) * sizeof (seen[0])); - next:; - } - } - - int relocation_in_progress = 0; - - for (size_t i = nmaps; i-- > 0; ) - { - l = maps[i]; - - if (! relocation_in_progress) - { - /* Notify the debugger that relocations are about to happen. */ - LIBC_PROBE (reloc_start, 2, args->nsid, r); - relocation_in_progress = 1; - } - -#ifdef SHARED - if (__glibc_unlikely (GLRO(dl_profile) != NULL)) - { - /* If this here is the shared object which we want to profile - make sure the profile is started. We can find out whether - this is necessary or not by observing the `_dl_profile_map' - variable. If it was NULL but is not NULL afterwards we must - start the profiling. */ - struct link_map *old_profile_map = GL(dl_profile_map); - - _dl_relocate_object (l, l->l_scope, reloc_mode | RTLD_LAZY, 1); - - if (old_profile_map == NULL && GL(dl_profile_map) != NULL) - { - /* We must prepare the profiling. */ - _dl_start_profile (); - - /* Prevent unloading the object. */ - GL(dl_profile_map)->l_flags_1 |= DF_1_NODELETE; - } - } - else -#endif - _dl_relocate_object (l, l->l_scope, reloc_mode, 0); - } - - /* If the file is not loaded now as a dependency, add the search - list of the newly loaded object to the scope. */ - bool any_tls = false; - unsigned int first_static_tls = new->l_searchlist.r_nlist; - for (unsigned int i = 0; i < new->l_searchlist.r_nlist; ++i) - { - struct link_map *imap = new->l_searchlist.r_list[i]; - int from_scope = 0; - - /* If the initializer has been called already, the object has - not been loaded here and now. */ - if (imap->l_init_called && imap->l_type == lt_loaded) - { - struct r_scope_elem **runp = imap->l_scope; - size_t cnt = 0; - - while (*runp != NULL) - { - if (*runp == &new->l_searchlist) - break; - ++cnt; - ++runp; - } - - if (*runp != NULL) - /* Avoid duplicates. */ - continue; - - if (__glibc_unlikely (cnt + 1 >= imap->l_scope_max)) - { - /* The 'r_scope' array is too small. Allocate a new one - dynamically. */ - size_t new_size; - struct r_scope_elem **newp; - -#define SCOPE_ELEMS(imap) \ - (sizeof (imap->l_scope_mem) / sizeof (imap->l_scope_mem[0])) - - if (imap->l_scope != imap->l_scope_mem - && imap->l_scope_max < SCOPE_ELEMS (imap)) - { - new_size = SCOPE_ELEMS (imap); - newp = imap->l_scope_mem; - } - else - { - new_size = imap->l_scope_max * 2; - newp = (struct r_scope_elem **) - malloc (new_size * sizeof (struct r_scope_elem *)); - if (newp == NULL) - _dl_signal_error (ENOMEM, "dlopen", NULL, - N_("cannot create scope list")); - } - - memcpy (newp, imap->l_scope, cnt * sizeof (imap->l_scope[0])); - struct r_scope_elem **old = imap->l_scope; - - imap->l_scope = newp; - - if (old != imap->l_scope_mem) - _dl_scope_free (old); - - imap->l_scope_max = new_size; - } - - /* First terminate the extended list. Otherwise a thread - might use the new last element and then use the garbage - at offset IDX+1. */ - imap->l_scope[cnt + 1] = NULL; - atomic_write_barrier (); - imap->l_scope[cnt] = &new->l_searchlist; - - /* Print only new scope information. */ - from_scope = cnt; - } - /* Only add TLS memory if this object is loaded now and - therefore is not yet initialized. */ - else if (! imap->l_init_called - /* Only if the module defines thread local data. */ - && __builtin_expect (imap->l_tls_blocksize > 0, 0)) - { - /* Now that we know the object is loaded successfully add - modules containing TLS data to the slot info table. We - might have to increase its size. */ - _dl_add_to_slotinfo (imap); - - if (imap->l_need_tls_init - && first_static_tls == new->l_searchlist.r_nlist) - first_static_tls = i; - - /* We have to bump the generation counter. */ - any_tls = true; - } - - /* Print scope information. */ - if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_SCOPES)) - _dl_show_scope (imap, from_scope); - } - - /* Bump the generation number if necessary. */ - if (any_tls && __builtin_expect (++GL(dl_tls_generation) == 0, 0)) - _dl_fatal_printf (N_("\ -TLS generation counter wrapped! Please report this.")); - - /* We need a second pass for static tls data, because _dl_update_slotinfo - must not be run while calls to _dl_add_to_slotinfo are still pending. */ - for (unsigned int i = first_static_tls; i < new->l_searchlist.r_nlist; ++i) - { - struct link_map *imap = new->l_searchlist.r_list[i]; - - if (imap->l_need_tls_init - && ! imap->l_init_called - && imap->l_tls_blocksize > 0) - { - /* For static TLS we have to allocate the memory here and - now, but we can delay updating the DTV. */ - imap->l_need_tls_init = 0; -#ifdef SHARED - /* Update the slot information data for at least the - generation of the DSO we are allocating data for. */ - _dl_update_slotinfo (imap->l_tls_modid); -#endif - - GL(dl_init_static_tls) (imap); - assert (imap->l_need_tls_init == 0); - } - } - - /* Notify the debugger all new objects have been relocated. */ - if (relocation_in_progress) - LIBC_PROBE (reloc_complete, 3, args->nsid, r, new); - -#ifndef SHARED - DL_STATIC_INIT (new); -#endif - - /* Run the initializer functions of new objects. */ - _dl_init (new, args->argc, args->argv, args->env); - - /* Now we can make the new map available in the global scope. */ - if (mode & RTLD_GLOBAL) - /* Move the object in the global namespace. */ - if (add_to_global (new) != 0) - /* It failed. */ - return; - -#ifndef SHARED - /* We must be the static _dl_open in libc.a. A static program that - has loaded a dynamic object now has competition. */ - __libc_multiple_libcs = 1; -#endif - - /* Let the user know about the opencount. */ - if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_FILES)) - _dl_debug_printf ("opening file=%s [%lu]; direct_opencount=%u\n\n", - new->l_name, new->l_ns, new->l_direct_opencount); -} - - -void * -_dl_open (const char *file, int mode, const void *caller_dlopen, Lmid_t nsid, - int argc, char *argv[], char *env[]) -{ - if ((mode & RTLD_BINDING_MASK) == 0) - /* One of the flags must be set. */ - _dl_signal_error (EINVAL, file, NULL, N_("invalid mode for dlopen()")); - - /* Make sure we are alone. */ - __rtld_lock_lock_recursive (GL(dl_load_lock)); - - if (__glibc_unlikely (nsid == LM_ID_NEWLM)) - { - /* Find a new namespace. */ - for (nsid = 1; DL_NNS > 1 && nsid < GL(dl_nns); ++nsid) - if (GL(dl_ns)[nsid]._ns_loaded == NULL) - break; - - if (__glibc_unlikely (nsid == DL_NNS)) - { - /* No more namespace available. */ - __rtld_lock_unlock_recursive (GL(dl_load_lock)); - - _dl_signal_error (EINVAL, file, NULL, N_("\ -no more namespaces available for dlmopen()")); - } - else if (nsid == GL(dl_nns)) - { - __rtld_lock_initialize (GL(dl_ns)[nsid]._ns_unique_sym_table.lock); - ++GL(dl_nns); - } - - _dl_debug_initialize (0, nsid)->r_state = RT_CONSISTENT; - } - /* Never allow loading a DSO in a namespace which is empty. Such - direct placements is only causing problems. Also don't allow - loading into a namespace used for auditing. */ - else if (__glibc_unlikely (nsid != LM_ID_BASE && nsid != __LM_ID_CALLER) - && (__glibc_unlikely (nsid < 0 || nsid >= GL(dl_nns)) - /* This prevents the [NSID] index expressions from being - evaluated, so the compiler won't think that we are - accessing an invalid index here in the !SHARED case where - DL_NNS is 1 and so any NSID != 0 is invalid. */ - || DL_NNS == 1 - || GL(dl_ns)[nsid]._ns_nloaded == 0 - || GL(dl_ns)[nsid]._ns_loaded->l_auditing)) - _dl_signal_error (EINVAL, file, NULL, - N_("invalid target namespace in dlmopen()")); - - struct dl_open_args args; - args.file = file; - args.mode = mode; - args.caller_dlopen = caller_dlopen; - args.caller_dl_open = RETURN_ADDRESS (0); - args.map = NULL; - args.nsid = nsid; - args.argc = argc; - args.argv = argv; - args.env = env; - - const char *objname; - const char *errstring; - bool malloced; - int errcode = _dl_catch_error (&objname, &errstring, &malloced, - dl_open_worker, &args); - -#if defined USE_LDCONFIG && !defined MAP_COPY - /* We must unmap the cache file. */ - _dl_unload_cache (); -#endif - - /* See if an error occurred during loading. */ - if (__glibc_unlikely (errstring != NULL)) - { - /* Remove the object from memory. It may be in an inconsistent - state if relocation failed, for example. */ - if (args.map) - { - /* Maybe some of the modules which were loaded use TLS. - Since it will be removed in the following _dl_close call - we have to mark the dtv array as having gaps to fill the - holes. This is a pessimistic assumption which won't hurt - if not true. There is no need to do this when we are - loading the auditing DSOs since TLS has not yet been set - up. */ - if ((mode & __RTLD_AUDIT) == 0) - GL(dl_tls_dtv_gaps) = true; - - _dl_close_worker (args.map, true); - } - - assert (_dl_debug_initialize (0, args.nsid)->r_state == RT_CONSISTENT); - - /* Release the lock. */ - __rtld_lock_unlock_recursive (GL(dl_load_lock)); - - /* Make a local copy of the error string so that we can release the - memory allocated for it. */ - size_t len_errstring = strlen (errstring) + 1; - char *local_errstring; - if (objname == errstring + len_errstring) - { - size_t total_len = len_errstring + strlen (objname) + 1; - local_errstring = alloca (total_len); - memcpy (local_errstring, errstring, total_len); - objname = local_errstring + len_errstring; - } - else - { - local_errstring = alloca (len_errstring); - memcpy (local_errstring, errstring, len_errstring); - } - - if (malloced) - free ((char *) errstring); - - /* Reraise the error. */ - _dl_signal_error (errcode, objname, NULL, local_errstring); - } - - assert (_dl_debug_initialize (0, args.nsid)->r_state == RT_CONSISTENT); - - /* Release the lock. */ - __rtld_lock_unlock_recursive (GL(dl_load_lock)); - - return args.map; -} - - -void -_dl_show_scope (struct link_map *l, int from) -{ - _dl_debug_printf ("object=%s [%lu]\n", - DSO_FILENAME (l->l_name), l->l_ns); - if (l->l_scope != NULL) - for (int scope_cnt = from; l->l_scope[scope_cnt] != NULL; ++scope_cnt) - { - _dl_debug_printf (" scope %u:", scope_cnt); - - for (unsigned int cnt = 0; cnt < l->l_scope[scope_cnt]->r_nlist; ++cnt) - if (*l->l_scope[scope_cnt]->r_list[cnt]->l_name) - _dl_debug_printf_c (" %s", - l->l_scope[scope_cnt]->r_list[cnt]->l_name); - else - _dl_debug_printf_c (" %s", RTLD_PROGNAME); - - _dl_debug_printf_c ("\n"); - } - else - _dl_debug_printf (" no scope\n"); - _dl_debug_printf ("\n"); -} |