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"
44 #ifndef STANDARD_LIBRARY_PATH
45 #define STANDARD_LIBRARY_PATH "/usr/lib"
48 #define NEW(type) ((type *) xmalloc(sizeof(type)))
49 #define CNEW(type) ((type *) xcalloc(sizeof(type)))
51 /* We might as well do booleans like C++. */
52 typedef unsigned char bool;
56 extern size_t tls_last_offset;
57 extern size_t tls_last_size;
58 extern size_t tls_static_space;
59 extern int tls_dtv_generation;
60 extern int tls_max_index;
63 struct Struct_Obj_Entry;
65 /* Lists of shared objects */
66 typedef struct Struct_Objlist_Entry {
67 STAILQ_ENTRY(Struct_Objlist_Entry) link;
68 struct Struct_Obj_Entry *obj;
71 typedef STAILQ_HEAD(Struct_Objlist, Struct_Objlist_Entry) Objlist;
73 /* Types of init and fini functions */
74 typedef void (*InitFunc)(void);
76 /* Lists of shared object dependencies */
77 typedef struct Struct_Needed_Entry {
78 struct Struct_Needed_Entry *next;
79 struct Struct_Obj_Entry *obj;
80 unsigned long name; /* Offset of name in string table */
83 typedef struct Struct_Name_Entry {
84 STAILQ_ENTRY(Struct_Name_Entry) link;
89 typedef struct Struct_LockInfo {
90 void *context; /* Client context for creating locks */
91 void *thelock; /* The one big lock */
93 volatile int rcount; /* Number of readers holding lock */
94 volatile int wcount; /* Number of writers holding lock */
96 void *(*lock_create)(void *context);
97 void (*rlock_acquire)(void *lock);
98 void (*wlock_acquire)(void *lock);
99 void (*rlock_release)(void *lock);
100 void (*wlock_release)(void *lock);
101 void (*lock_destroy)(void *lock);
102 void (*context_destroy)(void *context);
105 typedef struct Struct_Ver_Entry {
112 #define VER_INFO_HIDDEN 0x01
115 * Shared object descriptor.
117 * Items marked with "(%)" are dynamically allocated, and must be freed
118 * when the structure is destroyed.
120 * CAUTION: It appears that the JDK port peeks into these structures.
121 * It looks at "next" and "mapbase" at least. Don't add new members
122 * near the front, until this can be straightened out.
124 typedef struct Struct_Obj_Entry {
126 * These two items have to be set right for compatibility with the
127 * original ElfKit crt1.o.
129 Elf_Size magic; /* Magic number (sanity check) */
130 Elf_Size version; /* Version number of struct format */
132 struct Struct_Obj_Entry *next;
133 char *path; /* Pathname of underlying file (%) */
134 char *origin_path; /* Directory path of origin file */
136 int dl_refcount; /* Number of times loaded by dlopen */
138 /* These items are computed by map_object() or by digest_phdr(). */
139 caddr_t mapbase; /* Base address of mapped region */
140 size_t mapsize; /* Size of mapped region in bytes */
141 size_t textsize; /* Size of text segment in bytes */
142 Elf_Addr vaddrbase; /* Base address in shared object file */
143 caddr_t relocbase; /* Relocation constant = mapbase - vaddrbase */
144 const Elf_Dyn *dynamic; /* Dynamic section */
145 caddr_t entry; /* Entry point */
146 const Elf_Phdr *phdr; /* Program header if it is mapped, else NULL */
147 size_t phsize; /* Size of program header in bytes */
148 const char *interp; /* Pathname of the interpreter, if any */
149 caddr_t relro_page; /* Address of first page of read-only data */
150 size_t relro_size; /* Size of relro page(s) in bytes */
152 /* TLS information */
153 int tlsindex; /* Index in DTV for this module */
154 void *tlsinit; /* Base address of TLS init block */
155 size_t tlsinitsize; /* Size of TLS init block for this module */
156 size_t tlssize; /* Size of TLS block for this module */
157 size_t tlsoffset; /* Offset of static TLS block for this module */
158 size_t tlsalign; /* Alignment of static TLS block */
160 /* Items from the dynamic section. */
161 Elf_Addr *pltgot; /* PLT or GOT, depending on architecture */
162 const Elf_Rel *rel; /* Relocation entries */
163 unsigned long relsize; /* Size in bytes of relocation info */
164 const Elf_Rela *rela; /* Relocation entries with addend */
165 unsigned long relasize; /* Size in bytes of addend relocation info */
166 const Elf_Rel *pltrel; /* PLT relocation entries */
167 unsigned long pltrelsize; /* Size in bytes of PLT relocation info */
168 const Elf_Rela *pltrela; /* PLT relocation entries with addend */
169 unsigned long pltrelasize; /* Size in bytes of PLT addend reloc info */
170 const Elf_Sym *symtab; /* Symbol table */
171 const char *strtab; /* String table */
172 unsigned long strsize; /* Size in bytes of string table */
174 const Elf_Verneed *verneed; /* Required versions. */
175 Elf_Word verneednum; /* Number of entries in verneed table */
176 const Elf_Verdef *verdef; /* Provided versions. */
177 Elf_Word verdefnum; /* Number of entries in verdef table */
178 const Elf_Versym *versyms; /* Symbol versions table */
180 const Elf_Hashelt *buckets; /* Hash table buckets array */
181 unsigned long nbuckets; /* Number of buckets */
182 const Elf_Hashelt *chains; /* Hash table chain array */
183 unsigned long nchains; /* Number of chains */
185 char *rpath; /* Search path specified in object */
186 Needed_Entry *needed; /* Shared objects needed by this one (%) */
188 STAILQ_HEAD(, Struct_Name_Entry) names; /* List of names for this object we
190 Ver_Entry *vertab; /* Versions required /defined by this object */
191 int vernum; /* Number of entries in vertab */
193 Elf_Addr init; /* Initialization function to call */
194 Elf_Addr fini; /* Termination function to call */
196 bool mainprog : 1; /* True if this is the main program */
197 bool rtld : 1; /* True if this is the dynamic linker */
198 bool textrel : 1; /* True if there are relocations to text seg */
199 bool symbolic : 1; /* True if generated with "-Bsymbolic" */
200 bool bind_now : 1; /* True if all relocations should be made first */
201 bool traced : 1; /* Already printed in ldd trace output */
202 bool jmpslots_done : 1; /* Already have relocated the jump slots */
203 bool init_done : 1; /* Already have added object to init list */
204 bool tls_done : 1; /* Already allocated offset for static TLS */
205 bool phdr_alloc : 1; /* Phdr is allocated and needs to be freed. */
206 bool z_origin : 1; /* Process rpath and soname tokens */
207 bool z_nodelete : 1; /* Do not unload the object and dependencies */
208 bool z_noopen : 1; /* Do not load on dlopen */
209 bool ref_nodel : 1; /* Refcount increased to prevent dlclose */
210 bool init_scanned: 1; /* Object is already on init list. */
211 bool on_fini_list: 1; /* Object is already on fini list. */
212 bool dag_inited : 1; /* Object has its DAG initialized. */
214 struct link_map linkmap; /* For GDB and dlinfo() */
215 Objlist dldags; /* Object belongs to these dlopened DAGs (%) */
216 Objlist dagmembers; /* DAG has these members (%) */
217 dev_t dev; /* Object's filesystem's device */
218 ino_t ino; /* Object's inode number */
219 void *priv; /* Platform-dependent */
222 #define RTLD_MAGIC 0xd550b87a
223 #define RTLD_VERSION 1
225 /* Flags to be passed into symlook_ family of functions. */
226 #define SYMLOOK_IN_PLT 0x01 /* Lookup for PLT symbol */
227 #define SYMLOOK_DLSYM 0x02 /* Return newest versioned symbol. Used by
230 /* Flags for load_object(). */
231 #define RTLD_LO_NOLOAD 0x01 /* dlopen() specified RTLD_NOLOAD. */
232 #define RTLD_LO_DLOPEN 0x02 /* Load_object() called from dlopen(). */
233 #define RTLD_LO_TRACE 0x04 /* Only tracing. */
234 #define RTLD_LO_NODELETE 0x08 /* Loaded object cannot be closed. */
237 * Symbol cache entry used during relocation to avoid multiple lookups
238 * of the same symbol.
240 typedef struct Struct_SymCache {
241 const Elf_Sym *sym; /* Symbol table entry */
242 const Obj_Entry *obj; /* Shared object which defines it */
245 struct Struct_RtldLockState {
250 void _rtld_error(const char *, ...) __printflike(1, 2);
251 Obj_Entry *map_object(int, const char *, const struct stat *);
252 void *xcalloc(size_t);
253 void *xmalloc(size_t);
254 char *xstrdup(const char *);
255 extern Elf_Addr _GLOBAL_OFFSET_TABLE_[];
257 void dump_relocations(Obj_Entry *);
258 void dump_obj_relocations(Obj_Entry *);
259 void dump_Elf_Rel(Obj_Entry *, const Elf_Rel *, u_long);
260 void dump_Elf_Rela(Obj_Entry *, const Elf_Rela *, u_long);
263 * Function declarations.
265 const char *basename(const char *);
266 unsigned long elf_hash(const char *);
267 const Elf_Sym *find_symdef(unsigned long, const Obj_Entry *,
268 const Obj_Entry **, int, SymCache *);
269 void init_pltgot(Obj_Entry *);
270 void lockdflt_init(void);
271 void obj_free(Obj_Entry *);
272 Obj_Entry *obj_new(void);
273 void _rtld_bind_start(void);
274 const Elf_Sym *symlook_obj(const char *, unsigned long, const Obj_Entry *,
275 const Ver_Entry *, int);
276 void *tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset);
277 struct tls_tcb *allocate_tls(Obj_Entry *);
278 void free_tls(struct tls_tcb *);
279 void *allocate_module_tls(int index);
280 bool allocate_tls_offset(Obj_Entry *obj);
281 void free_tls_offset(Obj_Entry *obj);
282 const Ver_Entry *fetch_ventry(const Obj_Entry *obj, unsigned long);
285 * MD function declarations.
287 int do_copy_relocations(Obj_Entry *);
288 int reloc_non_plt(Obj_Entry *, Obj_Entry *);
289 int reloc_plt(Obj_Entry *);
290 int reloc_jmpslots(Obj_Entry *);
291 void allocate_initial_tls(Obj_Entry *);