diff options
Diffstat (limited to 'elf/dl-open.c')
| -rw-r--r-- | elf/dl-open.c | 104 |
1 files changed, 65 insertions, 39 deletions
diff --git a/elf/dl-open.c b/elf/dl-open.c index ba3c266..5526065 100644 --- a/elf/dl-open.c +++ b/elf/dl-open.c @@ -1,5 +1,5 @@ /* Load a shared object at runtime, relocate it, and run its initializer. - Copyright (C) 1996-2024 Free Software Foundation, Inc. + Copyright (C) 1996-2025 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 @@ -49,8 +49,7 @@ struct dl_open_args { const char *file; int mode; - /* This is the caller of the dlopen() function. */ - const void *caller_dlopen; + struct link_map *caller_map; /* Derived from the caller address. */ struct link_map *map; /* Namespace ID. */ Lmid_t nsid; @@ -493,36 +492,29 @@ call_dl_init (void *closure) _dl_init (args->map, args->argc, args->argv, args->env); } +/* Return true if the object does not need any processing beyond the + l_direct_opencount update. Needs to be kept in sync with the logic + in dl_open_worker_begin after the l->l_searchlist.r_list != NULL check. + MODE is the dlopen mode argument. */ +static bool +is_already_fully_open (struct link_map *map, int mode) +{ + return (map != NULL /* An existing map was found. */ + /* dlopen completed initialization of this map. Maps with + l_type == lt_library start out as partially initialized. */ + && map->l_searchlist.r_list != NULL + /* The object is already in the global scope if requested. */ + && (!(mode & RTLD_GLOBAL) || map->l_global) + /* The object is already NODELETE if requested. */ + && (!(mode & RTLD_NODELETE) || map->l_nodelete_active)); +} + static void dl_open_worker_begin (void *a) { struct dl_open_args *args = a; const char *file = args->file; int mode = args->mode; - struct link_map *call_map = NULL; - - /* 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; - } /* The namespace ID is now known. Keep track of whether libc.so was already loaded, to determine whether it is necessary to call the @@ -538,9 +530,10 @@ dl_open_worker_begin (void *a) _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); + struct link_map *new = args->map; + if (new == NULL) + args->map = new = _dl_map_new_object (args->caller_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. */ @@ -557,7 +550,7 @@ dl_open_worker_begin (void *a) /* This object is directly loaded. */ ++new->l_direct_opencount; - /* It was already open. */ + /* It was already open. See is_already_fully_open above. */ if (__glibc_unlikely (new->l_searchlist.r_list != NULL)) { /* Let the user know about the opencount. */ @@ -594,6 +587,16 @@ dl_open_worker_begin (void *a) if ((mode & RTLD_GLOBAL) && new->l_global == 0) add_to_global_update (new); + /* It is not possible to run the ELF constructor for the new + link map if it has not executed yet: If this dlopen call came + from an ELF constructor that has not put that object into a + consistent state, completing initialization for the entire + scope will expose objects that have this partially + constructed object among its dependencies to this + inconsistent state. This could happen even with a benign + dlopen (NULL, RTLD_LAZY) call from a constructor of an + initially loaded shared object. */ + return; } @@ -617,9 +620,7 @@ dl_open_worker_begin (void *a) Perform partial initialization in this case. This must come after the symbol versioning initialization in _dl_check_map_versions. */ - if (map->l_info[DT_SONAME] != NULL - && strcmp (((const char *) D_PTR (map, l_info[DT_STRTAB]) - + map->l_info[DT_SONAME]->d_un.d_val), LD_SO) == 0) + if (l_soname (map) != NULL && strcmp (l_soname (map), LD_SO) == 0) __rtld_static_init (map); #endif } @@ -771,8 +772,7 @@ dl_open_worker (void *a) #ifdef SHARED bool was_not_consistent = r->r_state != RT_CONSISTENT; #endif - r->r_state = RT_CONSISTENT; - _dl_debug_state (); + _dl_debug_change_state (r, RT_CONSISTENT); LIBC_PROBE (map_complete, 3, nsid, r, args->map); #ifdef SHARED @@ -841,7 +841,7 @@ no more namespaces available for dlmopen()")); } GL(dl_ns)[nsid].libc_map = NULL; - _dl_debug_update (nsid)->r_state = RT_CONSISTENT; + _dl_debug_change_state (_dl_debug_update (nsid), RT_CONSISTENT); } /* Never allow loading a DSO in a namespace which is empty. Such direct placements is only causing problems. Also don't allow @@ -861,8 +861,6 @@ no more namespaces available for dlmopen()")); struct dl_open_args args; args.file = file; args.mode = mode; - args.caller_dlopen = caller_dlopen; - args.map = NULL; args.nsid = nsid; /* args.libc_already_loaded is always assigned by dl_open_worker (before any explicit/non-local returns). */ @@ -870,6 +868,34 @@ no more namespaces available for dlmopen()")); args.argv = argv; args.env = env; + /* Determine the caller's map if necessary. This is needed when we + don't know the namespace ID in which we have to put the new object, + in case we have a DST, or when the file name has no path in + which case we need to look along the RUNPATH/RPATH of the caller. */ + if (nsid == __LM_ID_CALLER || strchr (file, '$') != NULL + || strchr (file, '/') == NULL) + { + struct dl_find_object dlfo; + if (_dl_find_object ((void *) caller_dlopen, &dlfo) == 0) + args.caller_map = dlfo.dlfo_link_map; + else + /* By default we assume this is the main application. */ + args.caller_map = GL(dl_ns)[LM_ID_BASE]._ns_loaded; + if (args.nsid == __LM_ID_CALLER) + args.nsid = args.caller_map->l_ns; + } + else + args.caller_map = NULL; + + args.map = _dl_lookup_map (args.nsid, file); + if (is_already_fully_open (args.map, mode)) + { + /* We can use the fast path. */ + ++args.map->l_direct_opencount; + __rtld_lock_unlock_recursive (GL(dl_load_lock)); + return args.map; + } + struct dl_exception exception; int errcode = _dl_catch_exception (&exception, dl_open_worker, &args); |