2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 #ifndef RTLD_H /* { */
31 #include <machine/elf.h>
32 #include <sys/types.h>
33 #include <sys/queue.h>
35 #include <elf-hints.h>
41 #include "rtld_lock.h"
42 #include "rtld_machdep.h"
45 #undef STANDARD_LIBRARY_PATH
46 #undef _PATH_ELF_HINTS
47 #define _PATH_ELF_HINTS "/var/run/ld-elf32.so.hints"
48 /* For running 32 bit binaries */
49 #define STANDARD_LIBRARY_PATH "/lib32:/usr/lib32"
53 #ifndef STANDARD_LIBRARY_PATH
54 #define STANDARD_LIBRARY_PATH "/lib:/usr/lib"
60 #define NEW(type) ((type *) xmalloc(sizeof(type)))
61 #define CNEW(type) ((type *) xcalloc(sizeof(type)))
63 /* We might as well do booleans like C++. */
64 typedef unsigned char bool;
68 extern size_t tls_last_offset;
69 extern size_t tls_last_size;
70 extern size_t tls_static_space;
71 extern int tls_dtv_generation;
72 extern int tls_max_index;
75 struct Struct_Obj_Entry;
77 /* Lists of shared objects */
78 typedef struct Struct_Objlist_Entry {
79 STAILQ_ENTRY(Struct_Objlist_Entry) link;
80 struct Struct_Obj_Entry *obj;
83 typedef STAILQ_HEAD(Struct_Objlist, Struct_Objlist_Entry) Objlist;
85 /* Types of init and fini functions */
86 typedef void (*InitFunc)(void);
88 /* Lists of shared object dependencies */
89 typedef struct Struct_Needed_Entry {
90 struct Struct_Needed_Entry *next;
91 struct Struct_Obj_Entry *obj;
92 unsigned long name; /* Offset of name in string table */
95 typedef struct Struct_Name_Entry {
96 STAILQ_ENTRY(Struct_Name_Entry) link;
101 typedef struct Struct_LockInfo {
102 void *context; /* Client context for creating locks */
103 void *thelock; /* The one big lock */
104 /* Debugging aids. */
105 volatile int rcount; /* Number of readers holding lock */
106 volatile int wcount; /* Number of writers holding lock */
108 void *(*lock_create)(void *context);
109 void (*rlock_acquire)(void *lock);
110 void (*wlock_acquire)(void *lock);
111 void (*rlock_release)(void *lock);
112 void (*wlock_release)(void *lock);
113 void (*lock_destroy)(void *lock);
114 void (*context_destroy)(void *context);
117 typedef struct Struct_Ver_Entry {
124 #define VER_INFO_HIDDEN 0x01
127 * Shared object descriptor.
129 * Items marked with "(%)" are dynamically allocated, and must be freed
130 * when the structure is destroyed.
132 * CAUTION: It appears that the JDK port peeks into these structures.
133 * It looks at "next" and "mapbase" at least. Don't add new members
134 * near the front, until this can be straightened out.
136 typedef struct Struct_Obj_Entry {
138 * These two items have to be set right for compatibility with the
139 * original ElfKit crt1.o.
141 Elf_Size magic; /* Magic number (sanity check) */
142 Elf_Size version; /* Version number of struct format */
144 struct Struct_Obj_Entry *next;
145 char *path; /* Pathname of underlying file (%) */
146 char *origin_path; /* Directory path of origin file */
148 int dl_refcount; /* Number of times loaded by dlopen */
150 /* These items are computed by map_object() or by digest_phdr(). */
151 caddr_t mapbase; /* Base address of mapped region */
152 size_t mapsize; /* Size of mapped region in bytes */
153 size_t textsize; /* Size of text segment in bytes */
154 Elf_Addr vaddrbase; /* Base address in shared object file */
155 caddr_t relocbase; /* Relocation constant = mapbase - vaddrbase */
156 const Elf_Dyn *dynamic; /* Dynamic section */
157 caddr_t entry; /* Entry point */
158 const Elf_Phdr *phdr; /* Program header if it is mapped, else NULL */
159 size_t phsize; /* Size of program header in bytes */
160 const char *interp; /* Pathname of the interpreter, if any */
161 Elf_Word stack_flags;
163 /* TLS information */
164 int tlsindex; /* Index in DTV for this module */
165 void *tlsinit; /* Base address of TLS init block */
166 size_t tlsinitsize; /* Size of TLS init block for this module */
167 size_t tlssize; /* Size of TLS block for this module */
168 size_t tlsoffset; /* Offset of static TLS block for this module */
169 size_t tlsalign; /* Alignment of 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_Rel *pltrel; /* PLT relocation entries */
178 unsigned long pltrelsize; /* Size in bytes of PLT relocation info */
179 const Elf_Rela *pltrela; /* PLT relocation entries with addend */
180 unsigned long pltrelasize; /* Size in bytes of PLT addend reloc info */
181 const Elf_Sym *symtab; /* Symbol table */
182 const char *strtab; /* String table */
183 unsigned long strsize; /* Size in bytes of string table */
185 Elf_Word local_gotno; /* Number of local GOT entries */
186 Elf_Word symtabno; /* Number of dynamic symbols */
187 Elf_Word gotsym; /* First dynamic symbol in GOT */
190 const Elf_Verneed *verneed; /* Required versions. */
191 Elf_Word verneednum; /* Number of entries in verneed table */
192 const Elf_Verdef *verdef; /* Provided versions. */
193 Elf_Word verdefnum; /* Number of entries in verdef table */
194 const Elf_Versym *versyms; /* Symbol versions table */
196 const Elf_Hashelt *buckets; /* Hash table buckets array */
197 unsigned long nbuckets; /* Number of buckets */
198 const Elf_Hashelt *chains; /* Hash table chain array */
199 unsigned long nchains; /* Number of chains */
201 char *rpath; /* Search path specified in object */
202 Needed_Entry *needed; /* Shared objects needed by this one (%) */
203 Needed_Entry *needed_filtees;
204 Needed_Entry *needed_aux_filtees;
206 STAILQ_HEAD(, Struct_Name_Entry) names; /* List of names for this object we
208 Ver_Entry *vertab; /* Versions required /defined by this object */
209 int vernum; /* Number of entries in vertab */
211 Elf_Addr init; /* Initialization function to call */
212 Elf_Addr fini; /* Termination function to call */
214 bool mainprog : 1; /* True if this is the main program */
215 bool rtld : 1; /* True if this is the dynamic linker */
216 bool textrel : 1; /* True if there are relocations to text seg */
217 bool symbolic : 1; /* True if generated with "-Bsymbolic" */
218 bool bind_now : 1; /* True if all relocations should be made first */
219 bool traced : 1; /* Already printed in ldd trace output */
220 bool jmpslots_done : 1; /* Already have relocated the jump slots */
221 bool init_done : 1; /* Already have added object to init list */
222 bool tls_done : 1; /* Already allocated offset for static TLS */
223 bool phdr_alloc : 1; /* Phdr is allocated and needs to be freed. */
224 bool z_origin : 1; /* Process rpath and soname tokens */
225 bool z_nodelete : 1; /* Do not unload the object and dependencies */
226 bool z_noopen : 1; /* Do not load on dlopen */
227 bool z_loadfltr : 1; /* Immediately load filtees */
228 bool ref_nodel : 1; /* Refcount increased to prevent dlclose */
229 bool init_scanned: 1; /* Object is already on init list. */
230 bool on_fini_list: 1; /* Object is already on fini list. */
231 bool dag_inited : 1; /* Object has its DAG initialized. */
232 bool filtees_loaded : 1; /* Filtees loaded */
234 struct link_map linkmap; /* For GDB and dlinfo() */
235 Objlist dldags; /* Object belongs to these dlopened DAGs (%) */
236 Objlist dagmembers; /* DAG has these members (%) */
237 dev_t dev; /* Object's filesystem's device */
238 ino_t ino; /* Object's inode number */
239 void *priv; /* Platform-dependant */
242 #define RTLD_MAGIC 0xd550b87a
243 #define RTLD_VERSION 1
245 #define RTLD_STATIC_TLS_EXTRA 128
247 /* Flags to be passed into symlook_ family of functions. */
248 #define SYMLOOK_IN_PLT 0x01 /* Lookup for PLT symbol */
249 #define SYMLOOK_DLSYM 0x02 /* Return newes versioned symbol. Used by
252 /* Flags for load_object(). */
253 #define RTLD_LO_NOLOAD 0x01 /* dlopen() specified RTLD_NOLOAD. */
254 #define RTLD_LO_DLOPEN 0x02 /* Load_object() called from dlopen(). */
255 #define RTLD_LO_TRACE 0x04 /* Only tracing. */
256 #define RTLD_LO_NODELETE 0x08 /* Loaded object cannot be closed. */
257 #define RTLD_LO_FILTEES 0x10 /* Loading filtee. */
260 * Symbol cache entry used during relocation to avoid multiple lookups
261 * of the same symbol.
263 typedef struct Struct_SymCache {
264 const Elf_Sym *sym; /* Symbol table entry */
265 const Obj_Entry *obj; /* Shared object which defines it */
269 * This structure provides a reentrant way to keep a list of objects and
270 * check which ones have already been processed in some way.
272 typedef struct Struct_DoneList {
273 const Obj_Entry **objs; /* Array of object pointers */
274 unsigned int num_alloc; /* Allocated size of the array */
275 unsigned int num_used; /* Number of array slots used */
278 struct Struct_RtldLockState {
284 * The pack of arguments and results for the symbol lookup functions.
286 typedef struct Struct_SymLook {
289 const Ver_Entry *ventry;
291 const Obj_Entry *defobj_out;
292 const Elf_Sym *sym_out;
293 struct Struct_RtldLockState *lockstate;
296 extern void _rtld_error(const char *, ...) __printflike(1, 2);
297 extern Obj_Entry *map_object(int, const char *, const struct stat *);
298 extern void *xcalloc(size_t);
299 extern void *xmalloc(size_t);
300 extern char *xstrdup(const char *);
301 extern Elf_Addr _GLOBAL_OFFSET_TABLE_[];
302 extern Elf_Sym sym_zero; /* For resolving undefined weak refs. */
304 extern void dump_relocations (Obj_Entry *);
305 extern void dump_obj_relocations (Obj_Entry *);
306 extern void dump_Elf_Rel (Obj_Entry *, const Elf_Rel *, u_long);
307 extern void dump_Elf_Rela (Obj_Entry *, const Elf_Rela *, u_long);
310 * Function declarations.
312 unsigned long elf_hash(const char *);
313 const Elf_Sym *find_symdef(unsigned long, const Obj_Entry *,
314 const Obj_Entry **, int, SymCache *, struct Struct_RtldLockState *);
315 void init_pltgot(Obj_Entry *);
316 void lockdflt_init(void);
317 void obj_free(Obj_Entry *);
318 Obj_Entry *obj_new(void);
319 void _rtld_bind_start(void);
320 void symlook_init(SymLook *, const char *);
321 int symlook_obj(SymLook *, const Obj_Entry *);
322 void *tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset);
323 void *allocate_tls(Obj_Entry *, void *, size_t, size_t);
324 void free_tls(void *, size_t, size_t);
325 void *allocate_module_tls(int index);
326 bool allocate_tls_offset(Obj_Entry *obj);
327 void free_tls_offset(Obj_Entry *obj);
328 const Ver_Entry *fetch_ventry(const Obj_Entry *obj, unsigned long);
331 * MD function declarations.
333 int do_copy_relocations(Obj_Entry *);
334 int reloc_non_plt(Obj_Entry *, Obj_Entry *, struct Struct_RtldLockState *);
335 int reloc_plt(Obj_Entry *);
336 int reloc_jmpslots(Obj_Entry *, struct Struct_RtldLockState *);
337 void allocate_initial_tls(Obj_Entry *);