rtld: Implement ELF filters (DT_FILTER and DT_AUXILIARY)
[dragonfly.git] / libexec / rtld-elf / rtld.h
CommitLineData
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1/*-
2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
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.
13 *
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.
24 *
f4f4bfd5 25 * $FreeBSD$
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26 */
27
28#ifndef RTLD_H /* { */
29#define RTLD_H 1
30
31#include <machine/elf.h>
32#include <sys/types.h>
33#include <sys/queue.h>
34
35#include <elf-hints.h>
36#include <link.h>
abfcd5b1 37#include <stdarg.h>
fcf53d9b 38#include <setjmp.h>
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39#include <stddef.h>
40
fcf53d9b 41#include "rtld_lock.h"
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42#include "rtld_machdep.h"
43
44#ifndef STANDARD_LIBRARY_PATH
45#define STANDARD_LIBRARY_PATH "/usr/lib"
46#endif
47
48#define NEW(type) ((type *) xmalloc(sizeof(type)))
49#define CNEW(type) ((type *) xcalloc(sizeof(type)))
50
51/* We might as well do booleans like C++. */
52typedef unsigned char bool;
53#define false 0
54#define true 1
55
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56extern size_t tls_last_offset;
57extern size_t tls_last_size;
58extern size_t tls_static_space;
59extern int tls_dtv_generation;
60extern int tls_max_index;
61
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62struct stat;
63struct Struct_Obj_Entry;
64
65/* Lists of shared objects */
66typedef struct Struct_Objlist_Entry {
67 STAILQ_ENTRY(Struct_Objlist_Entry) link;
68 struct Struct_Obj_Entry *obj;
69} Objlist_Entry;
70
71typedef STAILQ_HEAD(Struct_Objlist, Struct_Objlist_Entry) Objlist;
72
73/* Types of init and fini functions */
74typedef void (*InitFunc)(void);
75
76/* Lists of shared object dependencies */
77typedef 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 */
81} Needed_Entry;
82
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83typedef struct Struct_Name_Entry {
84 STAILQ_ENTRY(Struct_Name_Entry) link;
85 char name[1];
86} Name_Entry;
87
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88/* Lock object */
89typedef struct Struct_LockInfo {
90 void *context; /* Client context for creating locks */
91 void *thelock; /* The one big lock */
92 /* Debugging aids. */
93 volatile int rcount; /* Number of readers holding lock */
94 volatile int wcount; /* Number of writers holding lock */
95 /* Methods */
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);
103} LockInfo;
104
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105typedef struct Struct_Ver_Entry {
106 Elf_Word hash;
107 unsigned int flags;
108 const char *name;
109 const char *file;
110} Ver_Entry;
111
112#define VER_INFO_HIDDEN 0x01
113
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114/*
115 * Shared object descriptor.
116 *
117 * Items marked with "(%)" are dynamically allocated, and must be freed
118 * when the structure is destroyed.
119 *
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.
123 */
124typedef struct Struct_Obj_Entry {
125 /*
126 * These two items have to be set right for compatibility with the
127 * original ElfKit crt1.o.
128 */
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129 Elf_Size magic; /* Magic number (sanity check) */
130 Elf_Size version; /* Version number of struct format */
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131
132 struct Struct_Obj_Entry *next;
133 char *path; /* Pathname of underlying file (%) */
167f7029 134 char *origin_path; /* Directory path of origin file */
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135 int refcount;
136 int dl_refcount; /* Number of times loaded by dlopen */
137
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 */
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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 */
984263bc 151
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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 */
159
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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 */
173
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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 */
179
d697cc44 180 const Elf_Hashelt *buckets; /* Hash table buckets array */
984263bc 181 unsigned long nbuckets; /* Number of buckets */
d697cc44 182 const Elf_Hashelt *chains; /* Hash table chain array */
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183 unsigned long nchains; /* Number of chains */
184
fcf53d9b 185 char *rpath; /* Search path specified in object */
984263bc 186 Needed_Entry *needed; /* Shared objects needed by this one (%) */
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187 Needed_Entry *needed_filtees;
188 Needed_Entry *needed_aux_filtees;
984263bc 189
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190 STAILQ_HEAD(, Struct_Name_Entry) names; /* List of names for this object we
191 know about. */
192 Ver_Entry *vertab; /* Versions required /defined by this object */
193 int vernum; /* Number of entries in vertab */
194
195 Elf_Addr init; /* Initialization function to call */
196 Elf_Addr fini; /* Termination function to call */
197
198 bool mainprog : 1; /* True if this is the main program */
199 bool rtld : 1; /* True if this is the dynamic linker */
200 bool textrel : 1; /* True if there are relocations to text seg */
201 bool symbolic : 1; /* True if generated with "-Bsymbolic" */
202 bool bind_now : 1; /* True if all relocations should be made first */
203 bool traced : 1; /* Already printed in ldd trace output */
204 bool jmpslots_done : 1; /* Already have relocated the jump slots */
205 bool init_done : 1; /* Already have added object to init list */
206 bool tls_done : 1; /* Already allocated offset for static TLS */
207 bool phdr_alloc : 1; /* Phdr is allocated and needs to be freed. */
208 bool z_origin : 1; /* Process rpath and soname tokens */
209 bool z_nodelete : 1; /* Do not unload the object and dependencies */
210 bool z_noopen : 1; /* Do not load on dlopen */
35b2b265 211 bool z_loadfltr : 1; /* Immediately load filtees */
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212 bool ref_nodel : 1; /* Refcount increased to prevent dlclose */
213 bool init_scanned: 1; /* Object is already on init list. */
214 bool on_fini_list: 1; /* Object is already on fini list. */
215 bool dag_inited : 1; /* Object has its DAG initialized. */
35b2b265 216 bool filtees_loaded : 1; /* Filtees loaded */
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217
218 struct link_map linkmap; /* For GDB and dlinfo() */
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219 Objlist dldags; /* Object belongs to these dlopened DAGs (%) */
220 Objlist dagmembers; /* DAG has these members (%) */
221 dev_t dev; /* Object's filesystem's device */
222 ino_t ino; /* Object's inode number */
30aefd4f 223 void *priv; /* Platform-dependent */
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224} Obj_Entry;
225
226#define RTLD_MAGIC 0xd550b87a
227#define RTLD_VERSION 1
228
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229#define RTLD_FUNCTRACE "_rtld_functrace"
230
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231/* Flags to be passed into symlook_ family of functions. */
232#define SYMLOOK_IN_PLT 0x01 /* Lookup for PLT symbol */
30aefd4f 233#define SYMLOOK_DLSYM 0x02 /* Return newest versioned symbol. Used by
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234 dlsym. */
235
236/* Flags for load_object(). */
237#define RTLD_LO_NOLOAD 0x01 /* dlopen() specified RTLD_NOLOAD. */
238#define RTLD_LO_DLOPEN 0x02 /* Load_object() called from dlopen(). */
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239#define RTLD_LO_TRACE 0x04 /* Only tracing. */
240#define RTLD_LO_NODELETE 0x08 /* Loaded object cannot be closed. */
241#define RTLD_LO_FILTEES 0x10 /* Loading filtee. */
fcf53d9b 242
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243/*
244 * Symbol cache entry used during relocation to avoid multiple lookups
245 * of the same symbol.
246 */
247typedef struct Struct_SymCache {
248 const Elf_Sym *sym; /* Symbol table entry */
249 const Obj_Entry *obj; /* Shared object which defines it */
250} SymCache;
251
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252/*
253 * This structure provides a reentrant way to keep a list of objects and
254 * check which ones have already been processed in some way.
255 */
256typedef struct Struct_DoneList {
257 const Obj_Entry **objs; /* Array of object pointers */
258 unsigned int num_alloc; /* Allocated size of the array */
259 unsigned int num_used; /* Number of array slots used */
260} DoneList;
261
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262struct Struct_RtldLockState {
263 int lockstate;
264 sigjmp_buf env;
265};
266
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267/*
268 * The pack of arguments and results for the symbol lookup functions.
269 */
270typedef struct Struct_SymLook {
271 const char *name;
272 unsigned long hash;
273 const Ver_Entry *ventry;
274 int flags;
275 const Obj_Entry *defobj_out;
276 const Elf_Sym *sym_out;
277 struct Struct_RtldLockState *lockstate;
278} SymLook;
279
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280void _rtld_error(const char *, ...) __printflike(1, 2);
281Obj_Entry *map_object(int, const char *, const struct stat *);
282void *xcalloc(size_t);
283void *xmalloc(size_t);
284char *xstrdup(const char *);
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285extern Elf_Addr _GLOBAL_OFFSET_TABLE_[];
286
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287void dump_relocations(Obj_Entry *);
288void dump_obj_relocations(Obj_Entry *);
289void dump_Elf_Rel(Obj_Entry *, const Elf_Rel *, u_long);
290void dump_Elf_Rela(Obj_Entry *, const Elf_Rela *, u_long);
291
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292/*
293 * Function declarations.
294 */
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295const char *basename(const char *);
296unsigned long elf_hash(const char *);
297const Elf_Sym *find_symdef(unsigned long, const Obj_Entry *,
35b2b265 298 const Obj_Entry **, int, SymCache *, struct Struct_RtldLockState *);
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299void init_pltgot(Obj_Entry *);
300void lockdflt_init(void);
301void obj_free(Obj_Entry *);
302Obj_Entry *obj_new(void);
303void _rtld_bind_start(void);
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304void symlook_init(SymLook *, const char *);
305int symlook_obj(SymLook *, const Obj_Entry *);
fcf53d9b 306void *tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset);
a1eee96a 307struct tls_tcb *allocate_tls(Obj_Entry *);
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308void free_tls(struct tls_tcb *);
309void *allocate_module_tls(int index);
310bool allocate_tls_offset(Obj_Entry *obj);
311void free_tls_offset(Obj_Entry *obj);
312const Ver_Entry *fetch_ventry(const Obj_Entry *obj, unsigned long);
313
314/*
315 * MD function declarations.
316 */
317int do_copy_relocations(Obj_Entry *);
35b2b265 318int reloc_non_plt(Obj_Entry *, Obj_Entry *, struct Struct_RtldLockState *);
fcf53d9b 319int reloc_plt(Obj_Entry *);
35b2b265 320int reloc_jmpslots(Obj_Entry *, struct Struct_RtldLockState *);
fcf53d9b 321void allocate_initial_tls(Obj_Entry *);
139b8f34 322
984263bc 323#endif /* } */