2 * SPDX-License-Identifier: BSD-2-Clause
4 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 #ifndef RTLD_H /* { */
33 #include <machine/elf.h>
34 #include <sys/types.h>
35 #include <sys/queue.h>
37 #include <elf-hints.h>
44 #include "rtld_lock.h"
45 #include "rtld_machdep.h"
47 #define NEW(type) ((type *) xmalloc(sizeof(type)))
48 #define CNEW(type) ((type *) xcalloc(1, sizeof(type)))
50 extern size_t tls_last_offset;
51 extern size_t tls_last_size;
52 extern size_t tls_static_space;
53 extern Elf_Addr tls_dtv_generation;
54 extern int tls_max_index;
56 extern int npagesizes;
57 extern size_t *pagesizes;
58 extern size_t page_size;
61 extern char **main_argv;
62 extern char **environ;
65 struct Struct_Obj_Entry;
67 /* Lists of shared objects */
68 typedef struct Struct_Objlist_Entry {
69 STAILQ_ENTRY(Struct_Objlist_Entry) link;
70 struct Struct_Obj_Entry *obj;
73 typedef STAILQ_HEAD(Struct_Objlist, Struct_Objlist_Entry) Objlist;
75 /* Types of init and fini functions */
76 typedef void (*InitFunc)(void);
77 typedef void (*InitArrFunc)(int, char **, char **);
79 /* Lists of shared object dependencies */
80 typedef struct Struct_Needed_Entry {
81 struct Struct_Needed_Entry *next;
82 struct Struct_Obj_Entry *obj;
83 unsigned long name; /* Offset of name in string table */
86 typedef struct Struct_Name_Entry {
87 STAILQ_ENTRY(Struct_Name_Entry) link;
92 typedef struct Struct_LockInfo {
93 void *context; /* Client context for creating locks */
94 void *thelock; /* The one big lock */
96 volatile int rcount; /* Number of readers holding lock */
97 volatile int wcount; /* Number of writers holding lock */
99 void *(*lock_create)(void *context);
100 void (*rlock_acquire)(void *lock);
101 void (*wlock_acquire)(void *lock);
102 void (*rlock_release)(void *lock);
103 void (*wlock_release)(void *lock);
104 void (*lock_destroy)(void *lock);
105 void (*context_destroy)(void *context);
108 typedef struct Struct_Ver_Entry {
115 typedef struct Struct_Sym_Match_Result {
116 const Elf_Sym *sym_out;
117 const Elf_Sym *vsymp;
121 #define VER_INFO_HIDDEN 0x01
124 * Shared object descriptor.
126 * Items marked with "(%)" are dynamically allocated, and must be freed
127 * when the structure is destroyed.
129 * CAUTION: It appears that the JDK port peeks into these structures.
130 * It looks at "next" and "mapbase" at least. Don't add new members
131 * near the front, until this can be straightened out.
133 typedef struct Struct_Obj_Entry {
135 * These two items have to be set right for compatibility with the
136 * original ElfKit crt1.o.
138 Elf_Size magic; /* Magic number (sanity check) */
139 Elf_Size version; /* Version number of struct format */
141 TAILQ_ENTRY(Struct_Obj_Entry) next;
142 char *path; /* Pathname of underlying file (%) */
143 char *origin_path; /* Directory path of origin file */
144 int refcount; /* DAG references */
145 int holdcount; /* Count of transient references */
146 int dl_refcount; /* Number of times loaded by dlopen */
148 /* These items are computed by map_object() or by digest_phdr(). */
149 caddr_t mapbase; /* Base address of mapped region */
150 size_t mapsize; /* Size of mapped region in bytes */
151 Elf_Addr vaddrbase; /* Base address in shared object file */
152 caddr_t relocbase; /* Relocation constant = mapbase - vaddrbase */
153 const Elf_Dyn *dynamic; /* Dynamic section */
154 caddr_t entry; /* Entry point */
155 const Elf_Phdr *phdr; /* Program header if it is mapped, else NULL */
156 size_t phsize; /* Size of program header in bytes */
157 const char *interp; /* Pathname of the interpreter, if any */
158 Elf_Word stack_flags;
160 /* TLS information */
161 int tlsindex; /* Index in DTV for this module */
162 void *tlsinit; /* Base address of TLS init block */
163 size_t tlsinitsize; /* Size of TLS init block for this module */
164 size_t tlssize; /* Size of TLS block for this module */
165 size_t tlsoffset; /* Offset of static TLS block for this module */
166 size_t tlsalign; /* Alignment of static TLS block */
167 size_t tlspoffset; /* p_offset of the static TLS block */
172 /* Items from the dynamic section. */
173 Elf_Addr *pltgot; /* PLT or GOT, depending on architecture */
174 const Elf_Rel *rel; /* Relocation entries */
175 unsigned long relsize; /* Size in bytes of relocation info */
176 const Elf_Rela *rela; /* Relocation entries with addend */
177 unsigned long relasize; /* Size in bytes of addend relocation info */
178 const Elf_Relr *relr; /* RELR relocation entries */
179 unsigned long relrsize; /* Size in bytes of RELR relocations */
180 const Elf_Rel *pltrel; /* PLT relocation entries */
181 unsigned long pltrelsize; /* Size in bytes of PLT relocation info */
182 const Elf_Rela *pltrela; /* PLT relocation entries with addend */
183 unsigned long pltrelasize; /* Size in bytes of PLT addend reloc info */
184 const Elf_Sym *symtab; /* Symbol table */
185 const char *strtab; /* String table */
186 unsigned long strsize; /* Size in bytes of string table */
189 Elf_Addr glink; /* GLINK PLT call stub section */
191 Elf_Addr *gotptr; /* GOT pointer (secure-plt only) */
195 const Elf_Verneed *verneed; /* Required versions. */
196 Elf_Word verneednum; /* Number of entries in verneed table */
197 const Elf_Verdef *verdef; /* Provided versions. */
198 Elf_Word verdefnum; /* Number of entries in verdef table */
199 const Elf_Versym *versyms; /* Symbol versions table */
201 const Elf_Hashelt *buckets; /* Hash table buckets array */
202 unsigned long nbuckets; /* Number of buckets */
203 const Elf_Hashelt *chains; /* Hash table chain array */
204 unsigned long nchains; /* Number of entries in chain array */
206 Elf32_Word nbuckets_gnu; /* Number of GNU hash buckets*/
207 Elf32_Word symndx_gnu; /* 1st accessible symbol on dynsym table */
208 Elf32_Word maskwords_bm_gnu; /* Bloom filter words - 1 (bitmask) */
209 Elf32_Word shift2_gnu; /* Bloom filter shift count */
210 Elf32_Word dynsymcount; /* Total entries in dynsym table */
211 const Elf_Addr *bloom_gnu; /* Bloom filter used by GNU hash func */
212 const Elf_Hashelt *buckets_gnu; /* GNU hash table bucket array */
213 const Elf_Hashelt *chain_zero_gnu; /* GNU hash table value array (Zeroed) */
215 const char *rpath; /* Search path specified in object */
216 const char *runpath; /* Search path with different priority */
217 Needed_Entry *needed; /* Shared objects needed by this one (%) */
218 Needed_Entry *needed_filtees;
219 Needed_Entry *needed_aux_filtees;
221 STAILQ_HEAD(, Struct_Name_Entry) names; /* List of names for this object we
223 Ver_Entry *vertab; /* Versions required /defined by this object */
224 int vernum; /* Number of entries in vertab */
226 Elf_Addr init; /* Initialization function to call */
227 Elf_Addr fini; /* Termination function to call */
228 Elf_Addr preinit_array; /* Pre-initialization array of functions */
229 Elf_Addr init_array; /* Initialization array of functions */
230 Elf_Addr fini_array; /* Termination array of functions */
231 int preinit_array_num; /* Number of entries in preinit_array */
232 int init_array_num; /* Number of entries in init_array */
233 int fini_array_num; /* Number of entries in fini_array */
235 int32_t osrel; /* OSREL note value */
236 uint32_t fctl0; /* FEATURE_CONTROL note desc[0] value */
238 bool mainprog : 1; /* True if this is the main program */
239 bool rtld : 1; /* True if this is the dynamic linker */
240 bool relocated : 1; /* True if processed by relocate_objects() */
241 bool ver_checked : 1; /* True if processed by rtld_verify_object_versions */
242 bool textrel : 1; /* True if there are relocations to text seg */
243 bool symbolic : 1; /* True if generated with "-Bsymbolic" */
244 bool bind_now : 1; /* True if all relocations should be made first */
245 bool traced : 1; /* Already printed in ldd trace output */
246 bool jmpslots_done : 1; /* Already have relocated the jump slots */
247 bool init_done : 1; /* Already have added object to init list */
248 bool tls_static : 1; /* Already allocated offset for static TLS */
249 bool tls_dynamic : 1; /* A non-static DTV entry has been allocated */
250 bool phdr_alloc : 1; /* Phdr is allocated and needs to be freed. */
251 bool z_origin : 1; /* Process rpath and soname tokens */
252 bool z_nodelete : 1; /* Do not unload the object and dependencies */
253 bool z_noopen : 1; /* Do not load on dlopen */
254 bool z_loadfltr : 1; /* Immediately load filtees */
255 bool z_interpose : 1; /* Interpose all objects but main */
256 bool z_nodeflib : 1; /* Don't search default library path */
257 bool z_global : 1; /* Make the object global */
258 bool z_pie : 1; /* Object proclaimed itself PIE executable */
259 bool static_tls : 1; /* Needs static TLS allocation */
260 bool static_tls_copied : 1; /* Needs static TLS copying */
261 bool ref_nodel : 1; /* Refcount increased to prevent dlclose */
262 bool init_scanned: 1; /* Object is already on init list. */
263 bool on_fini_list: 1; /* Object is already on fini list. */
264 bool dag_inited : 1; /* Object has its DAG initialized. */
265 bool filtees_loaded : 1; /* Filtees loaded */
266 bool irelative : 1; /* Object has R_MACHDEP_IRELATIVE relocs */
267 bool irelative_nonplt : 1; /* Object has R_MACHDEP_IRELATIVE non-plt relocs */
268 bool gnu_ifunc : 1; /* Object has references to STT_GNU_IFUNC */
269 bool non_plt_gnu_ifunc : 1; /* Object has non-plt IFUNC references */
270 bool ifuncs_resolved : 1; /* Object ifuncs were already resolved */
271 bool crt_no_init : 1; /* Object' crt does not call _init/_fini */
272 bool valid_hash_sysv : 1; /* A valid System V hash hash tag is available */
273 bool valid_hash_gnu : 1; /* A valid GNU hash tag is available */
274 bool dlopened : 1; /* dlopen()-ed (vs. load statically) */
275 bool marker : 1; /* marker on the global obj list */
276 bool unholdfree : 1; /* unmap upon last unhold */
277 bool doomed : 1; /* Object cannot be referenced */
279 struct link_map linkmap; /* For GDB and dlinfo() */
280 Objlist dldags; /* Object belongs to these dlopened DAGs (%) */
281 Objlist dagmembers; /* DAG has these members (%) */
282 dev_t dev; /* Object's filesystem's device */
283 ino_t ino; /* Object's inode number */
284 void *priv; /* Platform-dependent */
287 #define RTLD_MAGIC 0xd550b87a
288 #define RTLD_VERSION 1
290 TAILQ_HEAD(obj_entry_q, Struct_Obj_Entry);
292 #define RTLD_STATIC_TLS_EXTRA 128
294 /* Flags to be passed into symlook_ family of functions. */
295 #define SYMLOOK_IN_PLT 0x01 /* Lookup for PLT symbol */
296 #define SYMLOOK_DLSYM 0x02 /* Return newest versioned symbol. Used by
298 #define SYMLOOK_EARLY 0x04 /* Symlook is done during initialization. */
299 #define SYMLOOK_IFUNC 0x08 /* Allow IFUNC processing in
302 /* Flags for load_object(). */
303 #define RTLD_LO_NOLOAD 0x01 /* dlopen() specified RTLD_NOLOAD. */
304 #define RTLD_LO_DLOPEN 0x02 /* Load_object() called from dlopen(). */
305 #define RTLD_LO_TRACE 0x04 /* Only tracing. */
306 #define RTLD_LO_NODELETE 0x08 /* Loaded object cannot be closed. */
307 #define RTLD_LO_FILTEES 0x10 /* Loading filtee. */
308 #define RTLD_LO_EARLY 0x20 /* Do not call ctors, postpone it to the
309 initialization during the image start. */
310 #define RTLD_LO_IGNSTLS 0x40 /* Do not allocate static TLS */
311 #define RTLD_LO_DEEPBIND 0x80 /* Force symbolic for this object */
314 * Symbol cache entry used during relocation to avoid multiple lookups
315 * of the same symbol.
317 typedef struct Struct_SymCache {
318 const Elf_Sym *sym; /* Symbol table entry */
319 const Obj_Entry *obj; /* Shared object which defines it */
323 * This structure provides a reentrant way to keep a list of objects and
324 * check which ones have already been processed in some way.
326 typedef struct Struct_DoneList {
327 const Obj_Entry **objs; /* Array of object pointers */
328 unsigned int num_alloc; /* Allocated size of the array */
329 unsigned int num_used; /* Number of array slots used */
332 struct Struct_RtldLockState {
337 struct fill_search_info_args {
340 struct dl_serinfo *serinfo;
341 struct dl_serpath *serpath;
346 * The pack of arguments and results for the symbol lookup functions.
348 typedef struct Struct_SymLook {
352 const Ver_Entry *ventry;
354 const Obj_Entry *defobj_out;
355 const Elf_Sym *sym_out;
356 struct Struct_RtldLockState *lockstate;
359 void _rtld_error(const char *, ...) __printflike(1, 2) __exported;
360 void rtld_die(void) __dead2;
361 const char *rtld_strerror(int);
362 Obj_Entry *map_object(int, const char *, const struct stat *);
363 void *xcalloc(size_t, size_t);
364 void *xmalloc(size_t);
365 char *xstrdup(const char *);
366 void *malloc_aligned(size_t size, size_t align, size_t offset);
367 void free_aligned(void *ptr);
368 extern Elf_Addr _GLOBAL_OFFSET_TABLE_[];
369 extern Elf_Sym sym_zero; /* For resolving undefined weak refs. */
370 extern bool ld_bind_not;
371 extern bool ld_fast_sigblock;
373 void dump_relocations(Obj_Entry *);
374 void dump_obj_relocations(Obj_Entry *);
375 void dump_Elf_Rel(Obj_Entry *, const Elf_Rel *, u_long);
376 void dump_Elf_Rela(Obj_Entry *, const Elf_Rela *, u_long);
379 * Function declarations.
381 uintptr_t rtld_round_page(uintptr_t);
382 uintptr_t rtld_trunc_page(uintptr_t);
383 Elf32_Word elf_hash(const char *);
384 const Elf_Sym *find_symdef(unsigned long, const Obj_Entry *,
385 const Obj_Entry **, int, SymCache *, struct Struct_RtldLockState *);
386 void lockdflt_init(void);
387 void digest_notes(Obj_Entry *, Elf_Addr, Elf_Addr);
388 Obj_Entry *globallist_curr(const Obj_Entry *obj);
389 Obj_Entry *globallist_next(const Obj_Entry *obj);
390 void obj_free(Obj_Entry *);
391 Obj_Entry *obj_new(void);
392 Obj_Entry *obj_from_addr(const void *);
393 void _rtld_bind_start(void);
394 void *rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def);
395 void symlook_init(SymLook *, const char *);
396 int symlook_obj(SymLook *, const Obj_Entry *);
397 void *tls_get_addr_common(uintptr_t **dtvp, int index, size_t offset);
398 void *allocate_tls(Obj_Entry *, void *, size_t, size_t);
399 void free_tls(void *, size_t, size_t);
400 void *allocate_module_tls(int index);
401 bool allocate_tls_offset(Obj_Entry *obj);
402 void free_tls_offset(Obj_Entry *obj);
403 const Ver_Entry *fetch_ventry(const Obj_Entry *obj, unsigned long);
404 int convert_prot(int elfflags);
405 bool check_elf_headers(const Elf_Ehdr *hdr, const char *path);
408 * MD function declarations.
410 int do_copy_relocations(Obj_Entry *);
411 int reloc_non_plt(Obj_Entry *, Obj_Entry *, int flags,
412 struct Struct_RtldLockState *);
413 int reloc_plt(Obj_Entry *, int flags, struct Struct_RtldLockState *);
414 int reloc_jmpslots(Obj_Entry *, int flags, struct Struct_RtldLockState *);
415 int reloc_iresolve(Obj_Entry *, struct Struct_RtldLockState *);
416 int reloc_iresolve_nonplt(Obj_Entry *, struct Struct_RtldLockState *);
417 int reloc_gnu_ifunc(Obj_Entry *, int flags, struct Struct_RtldLockState *);
418 void ifunc_init(Elf_Auxinfo[__min_size(AT_COUNT)]);
419 void init_pltgot(Obj_Entry *);
420 void allocate_initial_tls(Obj_Entry *);
422 void *__crt_calloc(size_t num, size_t size);
423 void __crt_free(void *cp);
424 void *__crt_malloc(size_t nbytes);
425 void *__crt_realloc(void *cp, size_t nbytes);