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.
25 * $FreeBSD: src/libexec/rtld-elf/rtld.h,v 1.50 2011/02/09 09:20:27 kib Exp $
28 #ifndef RTLD_H /* { */
31 #include <machine/elf.h>
32 #include <sys/types.h>
33 #include <sys/queue.h>
35 #include <elf-hints.h>
40 #include "rtld_lock.h"
41 #include "rtld_machdep.h"
43 #ifndef STANDARD_LIBRARY_PATH
44 #define STANDARD_LIBRARY_PATH "/usr/lib"
47 #define NEW(type) ((type *) xmalloc(sizeof(type)))
48 #define CNEW(type) ((type *) xcalloc(sizeof(type)))
50 /* We might as well do booleans like C++. */
51 typedef unsigned char bool;
55 extern size_t tls_last_offset;
56 extern size_t tls_last_size;
57 extern size_t tls_static_space;
58 extern int tls_dtv_generation;
59 extern int tls_max_index;
62 struct Struct_Obj_Entry;
64 /* Lists of shared objects */
65 typedef struct Struct_Objlist_Entry {
66 STAILQ_ENTRY(Struct_Objlist_Entry) link;
67 struct Struct_Obj_Entry *obj;
70 typedef STAILQ_HEAD(Struct_Objlist, Struct_Objlist_Entry) Objlist;
72 /* Types of init and fini functions */
73 typedef void (*InitFunc)(void);
75 /* Lists of shared object dependencies */
76 typedef struct Struct_Needed_Entry {
77 struct Struct_Needed_Entry *next;
78 struct Struct_Obj_Entry *obj;
79 unsigned long name; /* Offset of name in string table */
82 typedef struct Struct_Name_Entry {
83 STAILQ_ENTRY(Struct_Name_Entry) link;
88 typedef struct Struct_LockInfo {
89 void *context; /* Client context for creating locks */
90 void *thelock; /* The one big lock */
92 volatile int rcount; /* Number of readers holding lock */
93 volatile int wcount; /* Number of writers holding lock */
95 void *(*lock_create)(void *context);
96 void (*rlock_acquire)(void *lock);
97 void (*wlock_acquire)(void *lock);
98 void (*rlock_release)(void *lock);
99 void (*wlock_release)(void *lock);
100 void (*lock_destroy)(void *lock);
101 void (*context_destroy)(void *context);
104 typedef struct Struct_Ver_Entry {
111 #define VER_INFO_HIDDEN 0x01
114 * Shared object descriptor.
116 * Items marked with "(%)" are dynamically allocated, and must be freed
117 * when the structure is destroyed.
119 * CAUTION: It appears that the JDK port peeks into these structures.
120 * It looks at "next" and "mapbase" at least. Don't add new members
121 * near the front, until this can be straightened out.
123 typedef struct Struct_Obj_Entry {
125 * These two items have to be set right for compatibility with the
126 * original ElfKit crt1.o.
128 Elf_Size magic; /* Magic number (sanity check) */
129 Elf_Size version; /* Version number of struct format */
131 struct Struct_Obj_Entry *next;
132 char *path; /* Pathname of underlying file (%) */
133 char *origin_path; /* Directory path of origin file */
135 int dl_refcount; /* Number of times loaded by dlopen */
137 /* These items are computed by map_object() or by digest_phdr(). */
138 caddr_t mapbase; /* Base address of mapped region */
139 size_t mapsize; /* Size of mapped region in bytes */
140 size_t textsize; /* Size of text segment in bytes */
141 Elf_Addr vaddrbase; /* Base address in shared object file */
142 caddr_t relocbase; /* Relocation constant = mapbase - vaddrbase */
143 const Elf_Dyn *dynamic; /* Dynamic section */
144 caddr_t entry; /* Entry point */
145 const Elf_Phdr *phdr; /* Program header if it is mapped, else NULL */
146 size_t phsize; /* Size of program header in bytes */
147 const char *interp; /* Pathname of the interpreter, if any */
149 /* TLS information */
150 int tlsindex; /* Index in DTV for this module */
151 void *tlsinit; /* Base address of TLS init block */
152 size_t tlsinitsize; /* Size of TLS init block for this module */
153 size_t tlssize; /* Size of TLS block for this module */
154 size_t tlsoffset; /* Offset of static TLS block for this module */
155 size_t tlsalign; /* Alignment of static TLS block */
157 /* Items from the dynamic section. */
158 Elf_Addr *pltgot; /* PLT or GOT, depending on architecture */
159 const Elf_Rel *rel; /* Relocation entries */
160 unsigned long relsize; /* Size in bytes of relocation info */
161 const Elf_Rela *rela; /* Relocation entries with addend */
162 unsigned long relasize; /* Size in bytes of addend relocation info */
163 const Elf_Rel *pltrel; /* PLT relocation entries */
164 unsigned long pltrelsize; /* Size in bytes of PLT relocation info */
165 const Elf_Rela *pltrela; /* PLT relocation entries with addend */
166 unsigned long pltrelasize; /* Size in bytes of PLT addend reloc info */
167 const Elf_Sym *symtab; /* Symbol table */
168 const char *strtab; /* String table */
169 unsigned long strsize; /* Size in bytes of string table */
171 const Elf_Verneed *verneed; /* Required versions. */
172 Elf_Word verneednum; /* Number of entries in verneed table */
173 const Elf_Verdef *verdef; /* Provided versions. */
174 Elf_Word verdefnum; /* Number of entries in verdef table */
175 const Elf_Versym *versyms; /* Symbol versions table */
177 const Elf_Hashelt *buckets; /* Hash table buckets array */
178 unsigned long nbuckets; /* Number of buckets */
179 const Elf_Hashelt *chains; /* Hash table chain array */
180 unsigned long nchains; /* Number of chains */
182 char *rpath; /* Search path specified in object */
183 Needed_Entry *needed; /* Shared objects needed by this one (%) */
185 STAILQ_HEAD(, Struct_Name_Entry) names; /* List of names for this object we
187 Ver_Entry *vertab; /* Versions required /defined by this object */
188 int vernum; /* Number of entries in vertab */
190 Elf_Addr init; /* Initialization function to call */
191 Elf_Addr fini; /* Termination function to call */
193 bool mainprog : 1; /* True if this is the main program */
194 bool rtld : 1; /* True if this is the dynamic linker */
195 bool textrel : 1; /* True if there are relocations to text seg */
196 bool symbolic : 1; /* True if generated with "-Bsymbolic" */
197 bool bind_now : 1; /* True if all relocations should be made first */
198 bool traced : 1; /* Already printed in ldd trace output */
199 bool jmpslots_done : 1; /* Already have relocated the jump slots */
200 bool init_done : 1; /* Already have added object to init list */
201 bool tls_done : 1; /* Already allocated offset for static TLS */
202 bool phdr_alloc : 1; /* Phdr is allocated and needs to be freed. */
203 bool z_origin : 1; /* Process rpath and soname tokens */
204 bool z_nodelete : 1; /* Do not unload the object and dependencies */
205 bool z_noopen : 1; /* Do not load on dlopen */
206 bool ref_nodel : 1; /* Refcount increased to prevent dlclose */
207 bool init_scanned: 1; /* Object is already on init list. */
208 bool on_fini_list: 1; /* Object is already on fini list. */
209 bool dag_inited : 1; /* Object has its DAG initialized. */
211 struct link_map linkmap; /* For GDB and dlinfo() */
212 Objlist dldags; /* Object belongs to these dlopened DAGs (%) */
213 Objlist dagmembers; /* DAG has these members (%) */
214 dev_t dev; /* Object's filesystem's device */
215 ino_t ino; /* Object's inode number */
216 void *priv; /* Platform-dependant */
219 #define RTLD_MAGIC 0xd550b87a
220 #define RTLD_VERSION 1
222 /* Flags to be passed into symlook_ family of functions. */
223 #define SYMLOOK_IN_PLT 0x01 /* Lookup for PLT symbol */
224 #define SYMLOOK_DLSYM 0x02 /* Return newes versioned symbol. Used by
227 /* Flags for load_object(). */
228 #define RTLD_LO_NOLOAD 0x01 /* dlopen() specified RTLD_NOLOAD. */
229 #define RTLD_LO_DLOPEN 0x02 /* Load_object() called from dlopen(). */
230 #define RTLD_LO_TRACE 0x04 /* Only tracing. */
231 #define RTLD_LO_NODELETE 0x08 /* Loaded object cannot be closed. */
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 struct Struct_RtldLockState {
247 void _rtld_error(const char *, ...) __printflike(1, 2);
248 Obj_Entry *map_object(int, const char *, const struct stat *);
249 void *xcalloc(size_t);
250 void *xmalloc(size_t);
251 char *xstrdup(const char *);
252 void *xrealloc(void *, size_t);
253 extern Elf_Addr _GLOBAL_OFFSET_TABLE_[];
255 void dump_relocations(Obj_Entry *);
256 void dump_obj_relocations(Obj_Entry *);
257 void dump_Elf_Rel(Obj_Entry *, const Elf_Rel *, u_long);
258 void dump_Elf_Rela(Obj_Entry *, const Elf_Rela *, u_long);
261 * Function declarations.
263 const char *basename(const char *);
264 unsigned long elf_hash(const char *);
265 const Elf_Sym *find_symdef(unsigned long, const Obj_Entry *,
266 const Obj_Entry **, int, SymCache *);
267 void init_pltgot(Obj_Entry *);
268 void lockdflt_init(void);
269 void obj_free(Obj_Entry *);
270 Obj_Entry *obj_new(void);
271 void _rtld_bind_start(void);
272 const Elf_Sym *symlook_obj(const char *, unsigned long, const Obj_Entry *,
273 const Ver_Entry *, int);
274 void *tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset);
275 struct tls_tcb *allocate_tls(Obj_Entry *);
276 void free_tls(struct tls_tcb *);
277 void *allocate_module_tls(int index);
278 bool allocate_tls_offset(Obj_Entry *obj);
279 void free_tls_offset(Obj_Entry *obj);
280 const Ver_Entry *fetch_ventry(const Obj_Entry *obj, unsigned long);
283 * MD function declarations.
285 int do_copy_relocations(Obj_Entry *);
286 int reloc_non_plt(Obj_Entry *, Obj_Entry *);
287 int reloc_plt(Obj_Entry *);
288 int reloc_jmpslots(Obj_Entry *);
289 void allocate_initial_tls(Obj_Entry *);