2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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;
60 extern char **main_argv;
61 extern char **environ;
64 struct Struct_Obj_Entry;
66 /* Lists of shared objects */
67 typedef struct Struct_Objlist_Entry {
68 STAILQ_ENTRY(Struct_Objlist_Entry) link;
69 struct Struct_Obj_Entry *obj;
72 typedef STAILQ_HEAD(Struct_Objlist, Struct_Objlist_Entry) Objlist;
74 /* Types of init and fini functions */
75 typedef void (*InitFunc)(void);
76 typedef void (*InitArrFunc)(int, char **, char **);
78 /* Lists of shared object dependencies */
79 typedef struct Struct_Needed_Entry {
80 struct Struct_Needed_Entry *next;
81 struct Struct_Obj_Entry *obj;
82 unsigned long name; /* Offset of name in string table */
85 typedef struct Struct_Name_Entry {
86 STAILQ_ENTRY(Struct_Name_Entry) link;
91 typedef struct Struct_LockInfo {
92 void *context; /* Client context for creating locks */
93 void *thelock; /* The one big lock */
95 volatile int rcount; /* Number of readers holding lock */
96 volatile int wcount; /* Number of writers holding lock */
98 void *(*lock_create)(void *context);
99 void (*rlock_acquire)(void *lock);
100 void (*wlock_acquire)(void *lock);
101 void (*rlock_release)(void *lock);
102 void (*wlock_release)(void *lock);
103 void (*lock_destroy)(void *lock);
104 void (*context_destroy)(void *context);
107 typedef struct Struct_Ver_Entry {
114 typedef struct Struct_Sym_Match_Result {
115 const Elf_Sym *sym_out;
116 const Elf_Sym *vsymp;
120 #define VER_INFO_HIDDEN 0x01
123 * Shared object descriptor.
125 * Items marked with "(%)" are dynamically allocated, and must be freed
126 * when the structure is destroyed.
128 * CAUTION: It appears that the JDK port peeks into these structures.
129 * It looks at "next" and "mapbase" at least. Don't add new members
130 * near the front, until this can be straightened out.
132 typedef struct Struct_Obj_Entry {
134 * These two items have to be set right for compatibility with the
135 * original ElfKit crt1.o.
137 Elf_Size magic; /* Magic number (sanity check) */
138 Elf_Size version; /* Version number of struct format */
140 TAILQ_ENTRY(Struct_Obj_Entry) next;
141 char *path; /* Pathname of underlying file (%) */
142 char *origin_path; /* Directory path of origin file */
143 int refcount; /* DAG references */
144 int holdcount; /* Count of transient references */
145 int dl_refcount; /* Number of times loaded by dlopen */
147 /* These items are computed by map_object() or by digest_phdr(). */
148 caddr_t mapbase; /* Base address of mapped region */
149 size_t mapsize; /* Size of mapped region in bytes */
150 Elf_Addr vaddrbase; /* Base address in shared object file */
151 caddr_t relocbase; /* Relocation constant = mapbase - vaddrbase */
152 const Elf_Dyn *dynamic; /* Dynamic section */
153 caddr_t entry; /* Entry point */
154 const Elf_Phdr *phdr; /* Program header if it is mapped, else NULL */
155 size_t phsize; /* Size of program header in bytes */
156 const char *interp; /* Pathname of the interpreter, if any */
157 Elf_Word stack_flags;
159 /* TLS information */
160 int tlsindex; /* Index in DTV for this module */
161 void *tlsinit; /* Base address of TLS init block */
162 size_t tlsinitsize; /* Size of TLS init block for this module */
163 size_t tlssize; /* Size of TLS block for this module */
164 size_t tlsoffset; /* Offset of static TLS block for this module */
165 size_t tlsalign; /* Alignment of static TLS block */
166 size_t tlspoffset; /* p_offset of the static TLS block */
171 /* Items from the dynamic section. */
172 Elf_Addr *pltgot; /* PLT or GOT, depending on architecture */
173 const Elf_Rel *rel; /* Relocation entries */
174 unsigned long relsize; /* Size in bytes of relocation info */
175 const Elf_Rela *rela; /* Relocation entries with addend */
176 unsigned long relasize; /* Size in bytes of addend relocation info */
177 const Elf_Relr *relr; /* RELR relocation entries */
178 unsigned long relrsize; /* Size in bytes of RELR relocations */
179 const Elf_Rel *pltrel; /* PLT relocation entries */
180 unsigned long pltrelsize; /* Size in bytes of PLT relocation info */
181 const Elf_Rela *pltrela; /* PLT relocation entries with addend */
182 unsigned long pltrelasize; /* Size in bytes of PLT addend reloc info */
183 const Elf_Sym *symtab; /* Symbol table */
184 const char *strtab; /* String table */
185 unsigned long strsize; /* Size in bytes of string table */
188 Elf_Addr glink; /* GLINK PLT call stub section */
190 Elf_Addr *gotptr; /* GOT pointer (secure-plt only) */
194 const Elf_Verneed *verneed; /* Required versions. */
195 Elf_Word verneednum; /* Number of entries in verneed table */
196 const Elf_Verdef *verdef; /* Provided versions. */
197 Elf_Word verdefnum; /* Number of entries in verdef table */
198 const Elf_Versym *versyms; /* Symbol versions table */
200 const Elf_Hashelt *buckets; /* Hash table buckets array */
201 unsigned long nbuckets; /* Number of buckets */
202 const Elf_Hashelt *chains; /* Hash table chain array */
203 unsigned long nchains; /* Number of entries in chain array */
205 Elf32_Word nbuckets_gnu; /* Number of GNU hash buckets*/
206 Elf32_Word symndx_gnu; /* 1st accessible symbol on dynsym table */
207 Elf32_Word maskwords_bm_gnu; /* Bloom filter words - 1 (bitmask) */
208 Elf32_Word shift2_gnu; /* Bloom filter shift count */
209 Elf32_Word dynsymcount; /* Total entries in dynsym table */
210 const Elf_Addr *bloom_gnu; /* Bloom filter used by GNU hash func */
211 const Elf_Hashelt *buckets_gnu; /* GNU hash table bucket array */
212 const Elf_Hashelt *chain_zero_gnu; /* GNU hash table value array (Zeroed) */
214 const char *rpath; /* Search path specified in object */
215 const char *runpath; /* Search path with different priority */
216 Needed_Entry *needed; /* Shared objects needed by this one (%) */
217 Needed_Entry *needed_filtees;
218 Needed_Entry *needed_aux_filtees;
220 STAILQ_HEAD(, Struct_Name_Entry) names; /* List of names for this object we
222 Ver_Entry *vertab; /* Versions required /defined by this object */
223 int vernum; /* Number of entries in vertab */
225 Elf_Addr init; /* Initialization function to call */
226 Elf_Addr fini; /* Termination function to call */
227 Elf_Addr preinit_array; /* Pre-initialization array of functions */
228 Elf_Addr init_array; /* Initialization array of functions */
229 Elf_Addr fini_array; /* Termination array of functions */
230 int preinit_array_num; /* Number of entries in preinit_array */
231 int init_array_num; /* Number of entries in init_array */
232 int fini_array_num; /* Number of entries in fini_array */
234 int32_t osrel; /* OSREL note value */
235 uint32_t fctl0; /* FEATURE_CONTROL note desc[0] value */
237 bool mainprog : 1; /* True if this is the main program */
238 bool rtld : 1; /* True if this is the dynamic linker */
239 bool relocated : 1; /* True if processed by relocate_objects() */
240 bool ver_checked : 1; /* True if processed by rtld_verify_object_versions */
241 bool textrel : 1; /* True if there are relocations to text seg */
242 bool symbolic : 1; /* True if generated with "-Bsymbolic" */
243 bool bind_now : 1; /* True if all relocations should be made first */
244 bool traced : 1; /* Already printed in ldd trace output */
245 bool jmpslots_done : 1; /* Already have relocated the jump slots */
246 bool init_done : 1; /* Already have added object to init list */
247 bool tls_done : 1; /* Already allocated offset for static TLS */
248 bool phdr_alloc : 1; /* Phdr is allocated and needs to be freed. */
249 bool z_origin : 1; /* Process rpath and soname tokens */
250 bool z_nodelete : 1; /* Do not unload the object and dependencies */
251 bool z_noopen : 1; /* Do not load on dlopen */
252 bool z_loadfltr : 1; /* Immediately load filtees */
253 bool z_interpose : 1; /* Interpose all objects but main */
254 bool z_nodeflib : 1; /* Don't search default library path */
255 bool z_global : 1; /* Make the object global */
256 bool z_pie : 1; /* Object proclaimed itself PIE executable */
257 bool static_tls : 1; /* Needs static TLS allocation */
258 bool static_tls_copied : 1; /* Needs static TLS copying */
259 bool ref_nodel : 1; /* Refcount increased to prevent dlclose */
260 bool init_scanned: 1; /* Object is already on init list. */
261 bool on_fini_list: 1; /* Object is already on fini list. */
262 bool dag_inited : 1; /* Object has its DAG initialized. */
263 bool filtees_loaded : 1; /* Filtees loaded */
264 bool irelative : 1; /* Object has R_MACHDEP_IRELATIVE relocs */
265 bool irelative_nonplt : 1; /* Object has R_MACHDEP_IRELATIVE non-plt relocs */
266 bool gnu_ifunc : 1; /* Object has references to STT_GNU_IFUNC */
267 bool non_plt_gnu_ifunc : 1; /* Object has non-plt IFUNC references */
268 bool ifuncs_resolved : 1; /* Object ifuncs were already resolved */
269 bool crt_no_init : 1; /* Object' crt does not call _init/_fini */
270 bool valid_hash_sysv : 1; /* A valid System V hash hash tag is available */
271 bool valid_hash_gnu : 1; /* A valid GNU hash tag is available */
272 bool dlopened : 1; /* dlopen()-ed (vs. load statically) */
273 bool marker : 1; /* marker on the global obj list */
274 bool unholdfree : 1; /* unmap upon last unhold */
275 bool doomed : 1; /* Object cannot be referenced */
277 struct link_map linkmap; /* For GDB and dlinfo() */
278 Objlist dldags; /* Object belongs to these dlopened DAGs (%) */
279 Objlist dagmembers; /* DAG has these members (%) */
280 dev_t dev; /* Object's filesystem's device */
281 ino_t ino; /* Object's inode number */
282 void *priv; /* Platform-dependent */
285 #define RTLD_MAGIC 0xd550b87a
286 #define RTLD_VERSION 1
288 TAILQ_HEAD(obj_entry_q, Struct_Obj_Entry);
290 #define RTLD_STATIC_TLS_EXTRA 128
292 /* Flags to be passed into symlook_ family of functions. */
293 #define SYMLOOK_IN_PLT 0x01 /* Lookup for PLT symbol */
294 #define SYMLOOK_DLSYM 0x02 /* Return newest versioned symbol. Used by
296 #define SYMLOOK_EARLY 0x04 /* Symlook is done during initialization. */
297 #define SYMLOOK_IFUNC 0x08 /* Allow IFUNC processing in
300 /* Flags for load_object(). */
301 #define RTLD_LO_NOLOAD 0x01 /* dlopen() specified RTLD_NOLOAD. */
302 #define RTLD_LO_DLOPEN 0x02 /* Load_object() called from dlopen(). */
303 #define RTLD_LO_TRACE 0x04 /* Only tracing. */
304 #define RTLD_LO_NODELETE 0x08 /* Loaded object cannot be closed. */
305 #define RTLD_LO_FILTEES 0x10 /* Loading filtee. */
306 #define RTLD_LO_EARLY 0x20 /* Do not call ctors, postpone it to the
307 initialization during the image start. */
308 #define RTLD_LO_IGNSTLS 0x40 /* Do not allocate static TLS */
309 #define RTLD_LO_DEEPBIND 0x80 /* Force symbolic for this object */
312 * Symbol cache entry used during relocation to avoid multiple lookups
313 * of the same symbol.
315 typedef struct Struct_SymCache {
316 const Elf_Sym *sym; /* Symbol table entry */
317 const Obj_Entry *obj; /* Shared object which defines it */
321 * This structure provides a reentrant way to keep a list of objects and
322 * check which ones have already been processed in some way.
324 typedef struct Struct_DoneList {
325 const Obj_Entry **objs; /* Array of object pointers */
326 unsigned int num_alloc; /* Allocated size of the array */
327 unsigned int num_used; /* Number of array slots used */
330 struct Struct_RtldLockState {
335 struct fill_search_info_args {
338 struct dl_serinfo *serinfo;
339 struct dl_serpath *serpath;
344 * The pack of arguments and results for the symbol lookup functions.
346 typedef struct Struct_SymLook {
350 const Ver_Entry *ventry;
352 const Obj_Entry *defobj_out;
353 const Elf_Sym *sym_out;
354 struct Struct_RtldLockState *lockstate;
357 void _rtld_error(const char *, ...) __printflike(1, 2) __exported;
358 void rtld_die(void) __dead2;
359 const char *rtld_strerror(int);
360 Obj_Entry *map_object(int, const char *, const struct stat *);
361 void *xcalloc(size_t, size_t);
362 void *xmalloc(size_t);
363 char *xstrdup(const char *);
364 void *malloc_aligned(size_t size, size_t align, size_t offset);
365 void free_aligned(void *ptr);
366 extern Elf_Addr _GLOBAL_OFFSET_TABLE_[];
367 extern Elf_Sym sym_zero; /* For resolving undefined weak refs. */
368 extern bool ld_bind_not;
369 extern bool ld_fast_sigblock;
371 void dump_relocations(Obj_Entry *);
372 void dump_obj_relocations(Obj_Entry *);
373 void dump_Elf_Rel(Obj_Entry *, const Elf_Rel *, u_long);
374 void dump_Elf_Rela(Obj_Entry *, const Elf_Rela *, u_long);
377 * Function declarations.
379 unsigned long elf_hash(const char *);
380 const Elf_Sym *find_symdef(unsigned long, const Obj_Entry *,
381 const Obj_Entry **, int, SymCache *, struct Struct_RtldLockState *);
382 void lockdflt_init(void);
383 void digest_notes(Obj_Entry *, Elf_Addr, Elf_Addr);
384 Obj_Entry *globallist_curr(const Obj_Entry *obj);
385 Obj_Entry *globallist_next(const Obj_Entry *obj);
386 void obj_free(Obj_Entry *);
387 Obj_Entry *obj_new(void);
388 Obj_Entry *obj_from_addr(const void *);
389 void _rtld_bind_start(void);
390 void *rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def);
391 void symlook_init(SymLook *, const char *);
392 int symlook_obj(SymLook *, const Obj_Entry *);
393 void *tls_get_addr_common(uintptr_t **dtvp, int index, size_t offset);
394 void *allocate_tls(Obj_Entry *, void *, size_t, size_t);
395 void free_tls(void *, size_t, size_t);
396 void *allocate_module_tls(int index);
397 bool allocate_tls_offset(Obj_Entry *obj);
398 void free_tls_offset(Obj_Entry *obj);
399 const Ver_Entry *fetch_ventry(const Obj_Entry *obj, unsigned long);
400 int convert_prot(int elfflags);
401 bool check_elf_headers(const Elf_Ehdr *hdr, const char *path);
404 * MD function declarations.
406 int do_copy_relocations(Obj_Entry *);
407 int reloc_non_plt(Obj_Entry *, Obj_Entry *, int flags,
408 struct Struct_RtldLockState *);
409 int reloc_plt(Obj_Entry *, int flags, struct Struct_RtldLockState *);
410 int reloc_jmpslots(Obj_Entry *, int flags, struct Struct_RtldLockState *);
411 int reloc_iresolve(Obj_Entry *, struct Struct_RtldLockState *);
412 int reloc_iresolve_nonplt(Obj_Entry *, struct Struct_RtldLockState *);
413 int reloc_gnu_ifunc(Obj_Entry *, int flags, struct Struct_RtldLockState *);
414 void ifunc_init(Elf_Auxinfo[__min_size(AT_COUNT)]);
415 void init_pltgot(Obj_Entry *);
416 void allocate_initial_tls(Obj_Entry *);
418 void *__crt_calloc(size_t num, size_t size);
419 void __crt_free(void *cp);
420 void *__crt_malloc(size_t nbytes);
421 void *__crt_realloc(void *cp, size_t nbytes);