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>
39 #include "rtld_lock.h"
40 #include "rtld_machdep.h"
43 #undef STANDARD_LIBRARY_PATH
44 #undef _PATH_ELF_HINTS
45 #define _PATH_ELF_HINTS "/var/run/ld-elf32.so.hints"
46 /* For running 32 bit binaries */
47 #define STANDARD_LIBRARY_PATH "/lib32:/usr/lib32"
51 #ifndef STANDARD_LIBRARY_PATH
52 #define STANDARD_LIBRARY_PATH "/lib:/usr/lib"
58 #define NEW(type) ((type *) xmalloc(sizeof(type)))
59 #define CNEW(type) ((type *) xcalloc(sizeof(type)))
61 /* We might as well do booleans like C++. */
62 typedef unsigned char bool;
66 extern size_t tls_last_offset;
67 extern size_t tls_last_size;
68 extern size_t tls_static_space;
69 extern int tls_dtv_generation;
70 extern int tls_max_index;
73 struct Struct_Obj_Entry;
75 /* Lists of shared objects */
76 typedef struct Struct_Objlist_Entry {
77 STAILQ_ENTRY(Struct_Objlist_Entry) link;
78 struct Struct_Obj_Entry *obj;
81 typedef STAILQ_HEAD(Struct_Objlist, Struct_Objlist_Entry) Objlist;
83 /* Types of init and fini functions */
84 typedef void (*InitFunc)(void);
86 /* Lists of shared object dependencies */
87 typedef struct Struct_Needed_Entry {
88 struct Struct_Needed_Entry *next;
89 struct Struct_Obj_Entry *obj;
90 unsigned long name; /* Offset of name in string table */
93 typedef struct Struct_Name_Entry {
94 STAILQ_ENTRY(Struct_Name_Entry) link;
99 typedef struct Struct_LockInfo {
100 void *context; /* Client context for creating locks */
101 void *thelock; /* The one big lock */
102 /* Debugging aids. */
103 volatile int rcount; /* Number of readers holding lock */
104 volatile int wcount; /* Number of writers holding lock */
106 void *(*lock_create)(void *context);
107 void (*rlock_acquire)(void *lock);
108 void (*wlock_acquire)(void *lock);
109 void (*rlock_release)(void *lock);
110 void (*wlock_release)(void *lock);
111 void (*lock_destroy)(void *lock);
112 void (*context_destroy)(void *context);
115 typedef struct Struct_Ver_Entry {
122 #define VER_INFO_HIDDEN 0x01
125 * Shared object descriptor.
127 * Items marked with "(%)" are dynamically allocated, and must be freed
128 * when the structure is destroyed.
130 * CAUTION: It appears that the JDK port peeks into these structures.
131 * It looks at "next" and "mapbase" at least. Don't add new members
132 * near the front, until this can be straightened out.
134 typedef struct Struct_Obj_Entry {
136 * These two items have to be set right for compatibility with the
137 * original ElfKit crt1.o.
139 Elf_Size magic; /* Magic number (sanity check) */
140 Elf_Size version; /* Version number of struct format */
142 struct Struct_Obj_Entry *next;
143 char *path; /* Pathname of underlying file (%) */
144 char *origin_path; /* Directory path of origin file */
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 size_t textsize; /* Size of text segment in bytes */
152 Elf_Addr vaddrbase; /* Base address in shared object file */
153 caddr_t relocbase; /* Relocation constant = mapbase - vaddrbase */
154 const Elf_Dyn *dynamic; /* Dynamic section */
155 caddr_t entry; /* Entry point */
156 const Elf_Phdr *phdr; /* Program header if it is mapped, else NULL */
157 size_t phsize; /* Size of program header in bytes */
158 const char *interp; /* Pathname of the interpreter, if any */
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 */
168 /* Items from the dynamic section. */
169 Elf_Addr *pltgot; /* PLT or GOT, depending on architecture */
170 const Elf_Rel *rel; /* Relocation entries */
171 unsigned long relsize; /* Size in bytes of relocation info */
172 const Elf_Rela *rela; /* Relocation entries with addend */
173 unsigned long relasize; /* Size in bytes of addend relocation info */
174 const Elf_Rel *pltrel; /* PLT relocation entries */
175 unsigned long pltrelsize; /* Size in bytes of PLT relocation info */
176 const Elf_Rela *pltrela; /* PLT relocation entries with addend */
177 unsigned long pltrelasize; /* Size in bytes of PLT addend reloc info */
178 const Elf_Sym *symtab; /* Symbol table */
179 const char *strtab; /* String table */
180 unsigned long strsize; /* Size in bytes of string table */
182 const Elf_Verneed *verneed; /* Required versions. */
183 Elf_Word verneednum; /* Number of entries in verneed table */
184 const Elf_Verdef *verdef; /* Provided versions. */
185 Elf_Word verdefnum; /* Number of entries in verdef table */
186 const Elf_Versym *versyms; /* Symbol versions table */
188 const Elf_Hashelt *buckets; /* Hash table buckets array */
189 unsigned long nbuckets; /* Number of buckets */
190 const Elf_Hashelt *chains; /* Hash table chain array */
191 unsigned long nchains; /* Number of chains */
193 const char *rpath; /* Search path specified in object */
194 Needed_Entry *needed; /* Shared objects needed by this one (%) */
196 STAILQ_HEAD(, Struct_Name_Entry) names; /* List of names for this object we
198 Ver_Entry *vertab; /* Versions required /defined by this object */
199 int vernum; /* Number of entries in vertab */
201 Elf_Addr init; /* Initialization function to call */
202 Elf_Addr fini; /* Termination function to call */
204 bool mainprog : 1; /* True if this is the main program */
205 bool rtld : 1; /* True if this is the dynamic linker */
206 bool textrel : 1; /* True if there are relocations to text seg */
207 bool symbolic : 1; /* True if generated with "-Bsymbolic" */
208 bool bind_now : 1; /* True if all relocations should be made first */
209 bool traced : 1; /* Already printed in ldd trace output */
210 bool jmpslots_done : 1; /* Already have relocated the jump slots */
211 bool init_done : 1; /* Already have added object to init list */
212 bool tls_done : 1; /* Already allocated offset for static TLS */
213 bool phdr_alloc : 1; /* Phdr is allocated and needs to be freed. */
215 struct link_map linkmap; /* for GDB and dlinfo() */
216 Objlist dldags; /* Object belongs to these dlopened DAGs (%) */
217 Objlist dagmembers; /* DAG has these members (%) */
218 dev_t dev; /* Object's filesystem's device */
219 ino_t ino; /* Object's inode number */
220 void *priv; /* Platform-dependant */
223 #define RTLD_MAGIC 0xd550b87a
224 #define RTLD_VERSION 1
226 #define RTLD_STATIC_TLS_EXTRA 64
228 /* Flags to be passed into symlook_ family of functions. */
229 #define SYMLOOK_IN_PLT 0x01 /* Lookup for PLT symbol */
230 #define SYMLOOK_DLSYM 0x02 /* Return newes versioned symbol. Used by
234 * Symbol cache entry used during relocation to avoid multiple lookups
235 * of the same symbol.
237 typedef struct Struct_SymCache {
238 const Elf_Sym *sym; /* Symbol table entry */
239 const Obj_Entry *obj; /* Shared object which defines it */
242 extern void _rtld_error(const char *, ...) __printflike(1, 2);
243 extern Obj_Entry *map_object(int, const char *, const struct stat *);
244 extern void *xcalloc(size_t);
245 extern void *xmalloc(size_t);
246 extern char *xstrdup(const char *);
247 extern Elf_Addr _GLOBAL_OFFSET_TABLE_[];
249 extern void dump_relocations (Obj_Entry *);
250 extern void dump_obj_relocations (Obj_Entry *);
251 extern void dump_Elf_Rel (Obj_Entry *, const Elf_Rel *, u_long);
252 extern void dump_Elf_Rela (Obj_Entry *, const Elf_Rela *, u_long);
255 * Function declarations.
257 unsigned long elf_hash(const char *);
258 const Elf_Sym *find_symdef(unsigned long, const Obj_Entry *,
259 const Obj_Entry **, int, SymCache *);
260 void init_pltgot(Obj_Entry *);
261 void lockdflt_init(void);
262 void obj_free(Obj_Entry *);
263 Obj_Entry *obj_new(void);
264 void _rtld_bind_start(void);
265 const Elf_Sym *symlook_obj(const char *, unsigned long, const Obj_Entry *,
266 const Ver_Entry *, int);
267 void *tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset);
268 void *allocate_tls(Obj_Entry *, void *, size_t, size_t);
269 void free_tls(void *, size_t, size_t);
270 void *allocate_module_tls(int index);
271 bool allocate_tls_offset(Obj_Entry *obj);
272 void free_tls_offset(Obj_Entry *obj);
273 const Ver_Entry *fetch_ventry(const Obj_Entry *obj, unsigned long);
276 * MD function declarations.
278 int do_copy_relocations(Obj_Entry *);
279 int reloc_non_plt(Obj_Entry *, Obj_Entry *);
280 int reloc_plt(Obj_Entry *);
281 int reloc_jmpslots(Obj_Entry *);
282 void allocate_initial_tls(Obj_Entry *);