diff options
Diffstat (limited to 'ldso/libdl')
| -rw-r--r-- | ldso/libdl/libdl.c | 325 |
1 files changed, 322 insertions, 3 deletions
diff --git a/ldso/libdl/libdl.c b/ldso/libdl/libdl.c index 8646a74d8..7f7f70bd9 100644 --- a/ldso/libdl/libdl.c +++ b/ldso/libdl/libdl.c @@ -35,13 +35,25 @@ #include <string.h> /* Needed for 'strstr' prototype' */ #include <stdbool.h> +#ifdef __UCLIBC_HAS_TLS__ +#include <tls.h> +#endif + +#if USE_TLS +#include <ldsodefs.h> +extern void (*_dl_init_static_tls) (struct link_map *); +extern void _dl_add_to_slotinfo(struct link_map *l); +#endif #ifdef SHARED +# if USE_TLS +# include <dl-tls.h> +extern struct link_map *_dl_update_slotinfo(unsigned long int req_modid); +# endif /* 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 *, struct elf_resolve *, int); extern struct elf_resolve * _dl_load_shared_library(int, struct dyn_elf **, struct elf_resolve *, char *, int); extern int _dl_fixup(struct dyn_elf *rpnt, int lazy); @@ -50,6 +62,7 @@ extern int _dl_errno; extern struct dyn_elf *_dl_symbol_tables; extern struct dyn_elf *_dl_handles; extern struct elf_resolve *_dl_loaded_modules; +extern void _dl_free (void *__ptr); extern struct r_debug *_dl_debug_addr; extern unsigned long _dl_error_number; extern void *(*_dl_malloc_function)(size_t); @@ -83,7 +96,7 @@ char *_dl_debug_reloc = NULL; char *_dl_debug_detail = NULL; char *_dl_debug_nofixups = NULL; char *_dl_debug_bindings = NULL; -int _dl_debug_file = NULL; +int _dl_debug_file = 2; #endif const char *_dl_progname = ""; /* Program name */ void *(*_dl_malloc_function)(size_t); @@ -97,6 +110,15 @@ struct r_debug *_dl_debug_addr = NULL; #include "../ldso/dl-array.c" #include "../ldso/dl-debug.c" + + +# if USE_TLS +/* + * Giving this initialized value preallocates some surplus bytes in the + * static TLS area, see __libc_setup_tls (libc-tls.c). + */ +size_t _dl_tls_static_size = 2048; +# endif #include LDSO_ELFINTERP #include "../ldso/dl-hash.c" #define _dl_trace_loaded_objects 0 @@ -133,6 +155,7 @@ static const char *const dl_error_names[] = { "Not an ELF shared library", "Unable to mmap file", "No dynamic section", + "Library contains unsupported TLS", #ifdef ELF_USES_RELOCA "Unable to process REL relocs", #else @@ -142,6 +165,111 @@ static const char *const dl_error_names[] = { "Unable to resolve symbol" }; + +#if USE_TLS +#ifdef SHARED +/* + * Systems which do not have tls_index also probably have to define + * DONT_USE_TLS_INDEX. + */ + +# ifndef __TLS_GET_ADDR +# define __TLS_GET_ADDR __tls_get_addr +# endif + +/* + * Return the symbol address given the map of the module it is in and + * the symbol record. This is used in dl-sym.c. + */ +static void * +internal_function +_dl_tls_symaddr(struct link_map *map, const Elf32_Addr st_value) +{ +# ifndef DONT_USE_TLS_INDEX + tls_index tmp = + { + .ti_module = map->l_tls_modid, + .ti_offset = st_value + }; + + return __TLS_GET_ADDR (&tmp); +# else + return __TLS_GET_ADDR (map->l_tls_modid, st_value); +# endif +} +#endif + +/* Returns true we an non-empty was found. */ +static bool +remove_slotinfo(size_t idx, struct dtv_slotinfo_list *listp, size_t disp, + bool should_be_there) +{ + if(idx - disp >= listp->len) + { + if(listp->next == NULL) + { + /* + * The index is not actually valid in the slotinfo list, + * because this object was closed before it was fully set + * up due to some error. + */ + _dl_assert(!should_be_there); + } + else + { + if(remove_slotinfo(idx, listp->next, disp + listp->len, + should_be_there)) + return true; + + /* + * No non-empty entry. Search from the end of this element's + * slotinfo array. + */ + idx = disp + listp->len; + } + } + else + { + struct link_map *old_map = listp->slotinfo[idx - disp].map; + + /* + * The entry might still be in its unused state if we are + * closing an object that wasn't fully set up. + */ + if(__builtin_expect(old_map != NULL, 1)) + { + _dl_assert(old_map->l_tls_modid == idx); + + /* Mark the entry as unused. */ + listp->slotinfo[idx - disp].gen = _dl_tls_generation + 1; + listp->slotinfo[idx - disp].map = NULL; + } + + /* + * If this is not the last currently used entry no need to + * look further. + */ + if (idx != _dl_tls_max_dtv_idx) + return true; + } + + while(idx - disp > (disp == 0 ? 1 + _dl_tls_static_nelem : 0)) + { + --idx; + + if(listp->slotinfo[idx - disp].map != NULL) + { + /* Found a new last used index. */ + _dl_tls_max_dtv_idx = idx; + return true; + } + } + + /* No non-entry in this list element. */ + return false; +} +#endif + void dl_cleanup(void) __attribute__ ((destructor)); void dl_cleanup(void) { @@ -165,6 +293,9 @@ void *dlopen(const char *libname, int flag) unsigned int nlist, i; struct elf_resolve **init_fini_list; static bool _dl_init; +#if USE_TLS + bool any_tls = false; +#endif /* A bit of sanity checking... */ if (!(flag & (RTLD_LAZY|RTLD_NOW))) { @@ -396,6 +527,52 @@ void *dlopen(const char *libname, int flag) } /* TODO: Should we set the protections of all pages back to R/O now ? */ + +#if USE_TLS + + for (i=0; i < nlist; i++) { + struct elf_resolve *tmp_tpnt = init_fini_list[i]; + /* Only add TLS memory if this object is loaded now and + therefore is not yet initialized. */ + + if (!(tmp_tpnt->init_flag & INIT_FUNCS_CALLED) + /* Only if the module defines thread local data. */ + && __builtin_expect (tmp_tpnt->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 ((struct link_map*)tmp_tpnt); + + /* It is the case in which we couldn't perform TLS static + initialization at relocation time, and we delayed it until + the relocation has been completed. */ + + if (tmp_tpnt->l_need_tls_init) { + tmp_tpnt->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 (tmp_tpnt->l_tls_modid); +# endif + + _dl_init_static_tls((struct link_map*)tmp_tpnt); + _dl_assert (tmp_tpnt->l_need_tls_init == 0); + } + + /* We have to bump the generation counter. */ + any_tls = true; + } + } + + /* Bump the generation number if necessary. */ + if (any_tls && __builtin_expect (++_dl_tls_generation == 0, 0)) { + _dl_debug_early("TLS generation counter wrapped! Please report this."); + _dl_exit(30); + } + +#endif + /* Notify the debugger we have added some objects. */ if (_dl_debug_addr) { dl_brk = (void (*)(void)) _dl_debug_addr->r_brk; @@ -445,6 +622,7 @@ void *dlsym(void *vhandle, const char *name) ElfW(Addr) from; struct dyn_elf *rpnt; void *ret; + struct elf_resolve *tls_tpnt = NULL; /* Nastiness to support underscore prefixes. */ #ifdef __UCLIBC_UNDERSCORES__ char tmp_buf[80]; @@ -499,7 +677,15 @@ void *dlsym(void *vhandle, const char *name) tpnt = NULL; if (handle == _dl_symbol_tables) tpnt = handle->dyn; /* Only search RTLD_GLOBAL objs if global object */ - ret = _dl_find_hash(name2, handle, tpnt, ELF_RTYPE_CLASS_DLSYM); + ret = _dl_find_hash(name2, handle, NULL, 0, &tls_tpnt); + +#if defined USE_TLS && defined SHARED + if(tls_tpnt) { + /* The found symbol is a thread-local storage variable. + Return the address for to the current thread. */ + ret = _dl_tls_symaddr ((struct link_map *)tls_tpnt, (Elf32_Addr)ret); + } +#endif /* * Nothing found. @@ -532,6 +718,12 @@ static int do_dlclose(void *vhandle, int need_fini) struct dyn_elf *handle; unsigned int end; unsigned int i, j; +#if USE_TLS + bool any_tls = false; + size_t tls_free_start = NO_TLS_OFFSET; + size_t tls_free_end = NO_TLS_OFFSET; + struct link_map *tls_lmap; +#endif handle = (struct dyn_elf *) vhandle; if (handle == _dl_symbol_tables) @@ -587,6 +779,118 @@ static int do_dlclose(void *vhandle, int need_fini) if (end < ppnt->p_vaddr + ppnt->p_memsz) end = ppnt->p_vaddr + ppnt->p_memsz; } + +#if USE_TLS + /* Do the cast to make things easy. */ + tls_lmap = (struct link_map *) tpnt; + + /* Remove the object from the dtv slotinfo array if it uses TLS. */ + if (__builtin_expect (tls_lmap->l_tls_blocksize > 0, 0)) + { + any_tls = true; + + if (_dl_tls_dtv_slotinfo_list != NULL + && ! remove_slotinfo (tls_lmap->l_tls_modid, + _dl_tls_dtv_slotinfo_list, 0, + (tpnt->init_flag & INIT_FUNCS_CALLED))) + /* All dynamically loaded modules with TLS are unloaded. */ + _dl_tls_max_dtv_idx = _dl_tls_static_nelem; + + if (tls_lmap->l_tls_offset != NO_TLS_OFFSET) + { + /* + * Collect a contiguous chunk built from the objects in + * this search list, going in either direction. When the + * whole chunk is at the end of the used area then we can + * reclaim it. + */ +# if defined(TLS_TCB_AT_TP) + if (tls_free_start == NO_TLS_OFFSET + || (size_t) tls_lmap->l_tls_offset == tls_free_start) + { + /* Extend the contiguous chunk being reclaimed. */ + tls_free_start + = tls_lmap->l_tls_offset - + tls_lmap->l_tls_blocksize; + + if (tls_free_end == NO_TLS_OFFSET) + tls_free_end = tls_lmap->l_tls_offset; + } + else if (tls_lmap->l_tls_offset - tls_lmap->l_tls_blocksize + == tls_free_end) + /* Extend the chunk backwards. */ + tls_free_end = tls_lmap->l_tls_offset; + else + { + /* + * This isn't contiguous with the last chunk freed. + * One of them will be leaked unless we can free + * one block right away. + */ + if (tls_free_end == _dl_tls_static_used) + { + _dl_tls_static_used = tls_free_start; + tls_free_end = tls_lmap->l_tls_offset; + tls_free_start + = tls_free_end - tls_lmap->l_tls_blocksize; + } + else if ((size_t) tls_lmap->l_tls_offset + == _dl_tls_static_used) + _dl_tls_static_used = tls_lmap->l_tls_offset - + tls_lmap->l_tls_blocksize; + else if (tls_free_end < (size_t) tls_lmap->l_tls_offset) + { + /* + * We pick the later block. It has a chance + * to be freed. + */ + tls_free_end = tls_lmap->l_tls_offset; + tls_free_start = tls_free_end - + tls_lmap->l_tls_blocksize; + } + } +# elif defined(TLS_DTV_AT_TP) + if ((size_t) tls_lmap->l_tls_offset == tls_free_end) + /* Extend the contiguous chunk being reclaimed. */ + tls_free_end -= tls_lmap->l_tls_blocksize; + else if (tls_lmap->l_tls_offset + tls_lmap->l_tls_blocksize + == tls_free_start) + /* Extend the chunk backwards. */ + tls_free_start = tls_lmap->l_tls_offset; + else + { + /* + * This isn't contiguous with the last chunk + * freed. One of them will be leaked. + */ + if (tls_free_end == _dl_tls_static_used) + _dl_tls_static_used = tls_free_start; + tls_free_start = tls_lmap->l_tls_offset; + tls_free_end = tls_free_start + + tls_lmap->l_tls_blocksize; + } +# else +# error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined" +# endif + } else { + +#define TLS_DTV_UNALLOCATED ((void *) -1l) + + dtv_t *dtv = THREAD_DTV (); + + _dl_assert(!(dtv[tls_lmap->l_tls_modid].pointer.is_static)); + if(dtv[tls_lmap->l_tls_modid].pointer.val != TLS_DTV_UNALLOCATED) { + /* Note that free is called for NULL is well. We + deallocate even if it is this dtv entry we are + supposed to load. The reason is that we call + memalign and not malloc. */ + _dl_free (dtv[tls_lmap->l_tls_modid].pointer.val); + dtv[tls_lmap->l_tls_modid].pointer.val = TLS_DTV_UNALLOCATED; + } + } + } +#endif + DL_LIB_UNMAP (tpnt, end); /* Free elements in RTLD_LOCAL scope list */ for (runp = tpnt->rtld_local; runp; runp = tmp) { @@ -638,6 +942,21 @@ static int do_dlclose(void *vhandle, int need_fini) free(handle->init_fini.init_fini); free(handle); +#if USE_TLS + /* If we removed any object which uses TLS bump the generation counter. */ + if (any_tls) + { + if (__builtin_expect (++_dl_tls_generation == 0, 0)) + { + _dl_debug_early ("TLS generation counter wrapped! Please report to the uClibc mailing list.\n"); + _dl_exit(30); + } + + if (tls_free_end == _dl_tls_static_used) + _dl_tls_static_used = tls_free_start; + } +#endif + if (_dl_debug_addr) { dl_brk = (void (*)(void)) _dl_debug_addr->r_brk; if (dl_brk != NULL) { |