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_machdep.h"
41 #ifndef STANDARD_LIBRARY_PATH
42 #define STANDARD_LIBRARY_PATH "/usr/lib/elf:/usr/lib"
45 #define NEW(type) ((type *) xmalloc(sizeof(type)))
46 #define CNEW(type) ((type *) xcalloc(sizeof(type)))
48 /* We might as well do booleans like C++. */
49 typedef unsigned char bool;
54 struct Struct_Obj_Entry;
56 /* Lists of shared objects */
57 typedef struct Struct_Objlist_Entry {
58 STAILQ_ENTRY(Struct_Objlist_Entry) link;
59 struct Struct_Obj_Entry *obj;
62 typedef STAILQ_HEAD(Struct_Objlist, Struct_Objlist_Entry) Objlist;
64 /* Types of init and fini functions */
65 typedef void (*InitFunc)(void);
67 /* Lists of shared object dependencies */
68 typedef struct Struct_Needed_Entry {
69 struct Struct_Needed_Entry *next;
70 struct Struct_Obj_Entry *obj;
71 unsigned long name; /* Offset of name in string table */
75 typedef struct Struct_LockInfo {
76 void *context; /* Client context for creating locks */
77 void *thelock; /* The one big lock */
79 volatile int rcount; /* Number of readers holding lock */
80 volatile int wcount; /* Number of writers holding lock */
82 void *(*lock_create)(void *context);
83 void (*rlock_acquire)(void *lock);
84 void (*wlock_acquire)(void *lock);
85 void (*rlock_release)(void *lock);
86 void (*wlock_release)(void *lock);
87 void (*lock_destroy)(void *lock);
88 void (*context_destroy)(void *context);
92 * Shared object descriptor.
94 * Items marked with "(%)" are dynamically allocated, and must be freed
95 * when the structure is destroyed.
97 * CAUTION: It appears that the JDK port peeks into these structures.
98 * It looks at "next" and "mapbase" at least. Don't add new members
99 * near the front, until this can be straightened out.
101 typedef struct Struct_Obj_Entry {
103 * These two items have to be set right for compatibility with the
104 * original ElfKit crt1.o.
106 Elf_Word magic; /* Magic number (sanity check) */
107 Elf_Word version; /* Version number of struct format */
109 struct Struct_Obj_Entry *next;
110 char *path; /* Pathname of underlying file (%) */
112 int dl_refcount; /* Number of times loaded by dlopen */
114 /* These items are computed by map_object() or by digest_phdr(). */
115 caddr_t mapbase; /* Base address of mapped region */
116 size_t mapsize; /* Size of mapped region in bytes */
117 size_t textsize; /* Size of text segment in bytes */
118 Elf_Addr vaddrbase; /* Base address in shared object file */
119 caddr_t relocbase; /* Relocation constant = mapbase - vaddrbase */
120 const Elf_Dyn *dynamic; /* Dynamic section */
121 caddr_t entry; /* Entry point */
122 const Elf_Phdr *phdr; /* Program header if it is mapped, else NULL */
123 size_t phsize; /* Size of program header in bytes */
124 const char *interp; /* Pathname of the interpreter, if any */
126 /* Items from the dynamic section. */
127 Elf_Addr *pltgot; /* PLT or GOT, depending on architecture */
128 const Elf_Rel *rel; /* Relocation entries */
129 unsigned long relsize; /* Size in bytes of relocation info */
130 const Elf_Rela *rela; /* Relocation entries with addend */
131 unsigned long relasize; /* Size in bytes of addend relocation info */
132 const Elf_Rel *pltrel; /* PLT relocation entries */
133 unsigned long pltrelsize; /* Size in bytes of PLT relocation info */
134 const Elf_Rela *pltrela; /* PLT relocation entries with addend */
135 unsigned long pltrelasize; /* Size in bytes of PLT addend reloc info */
136 const Elf_Sym *symtab; /* Symbol table */
137 const char *strtab; /* String table */
138 unsigned long strsize; /* Size in bytes of string table */
140 const Elf_Hashelt *buckets; /* Hash table buckets array */
141 unsigned long nbuckets; /* Number of buckets */
142 const Elf_Hashelt *chains; /* Hash table chain array */
143 unsigned long nchains; /* Number of chains */
145 const char *rpath; /* Search path specified in object */
146 Needed_Entry *needed; /* Shared objects needed by this one (%) */
148 Elf_Addr init; /* Initialization function to call */
149 Elf_Addr fini; /* Termination function to call */
151 bool mainprog; /* True if this is the main program */
152 bool rtld; /* True if this is the dynamic linker */
153 bool textrel; /* True if there are relocations to text seg */
154 bool symbolic; /* True if generated with "-Bsymbolic" */
155 bool traced; /* Already printed in ldd trace output */
156 bool jmpslots_done; /* Already have relocated the jump slots */
157 bool init_done; /* Already have added object to init list */
159 struct link_map linkmap; /* for GDB */
160 Objlist dldags; /* Object belongs to these dlopened DAGs (%) */
161 Objlist dagmembers; /* DAG has these members (%) */
162 dev_t dev; /* Object's filesystem's device */
163 ino_t ino; /* Object's inode number */
164 void *priv; /* Platform-dependant */
167 #define RTLD_MAGIC 0xd550b87a
168 #define RTLD_VERSION 1
171 * Symbol cache entry used during relocation to avoid multiple lookups
172 * of the same symbol.
174 typedef struct Struct_SymCache {
175 const Elf_Sym *sym; /* Symbol table entry */
176 const Obj_Entry *obj; /* Shared object which defines it */
179 extern void _rtld_error(const char *, ...) __printflike(1, 2);
180 extern Obj_Entry *map_object(int, const char *, const struct stat *);
181 extern void *xcalloc(size_t);
182 extern void *xmalloc(size_t);
183 extern char *xstrdup(const char *);
184 extern Elf_Addr _GLOBAL_OFFSET_TABLE_[];
187 * Function declarations.
189 int do_copy_relocations(Obj_Entry *);
190 unsigned long elf_hash(const char *);
191 const Elf_Sym *find_symdef(unsigned long, const Obj_Entry *,
192 const Obj_Entry **, bool, SymCache *);
193 void init_pltgot(Obj_Entry *);
194 void lockdflt_init(LockInfo *);
195 void obj_free(Obj_Entry *);
196 Obj_Entry *obj_new(void);
197 int reloc_non_plt(Obj_Entry *, Obj_Entry *);
198 int reloc_plt(Obj_Entry *);
199 int reloc_jmpslots(Obj_Entry *);
200 void _rtld_bind_start(void);
201 const Elf_Sym *symlook_obj(const char *, unsigned long,
202 const Obj_Entry *, bool);