rtld.h revision 50608 
1/*-
2 * Copyright 1996-1998 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 *
25 * $FreeBSD: head/libexec/rtld-elf/rtld.h 50608 1999-08-30 01:48:19Z jdp $
26 */
27
28#ifndef RTLD_H /* { */
29#define RTLD_H 1
30
31#include <sys/types.h>
32#include <sys/queue.h>
33
34#include <link.h>
35#include <elf.h>
36#include <stddef.h>
37
38#include "rtld_machdep.h"
39
40#ifndef STANDARD_LIBRARY_PATH
41#define STANDARD_LIBRARY_PATH	"/usr/lib/elf:/usr/lib"
42#endif
43
44#define NEW(type)	((type *) xmalloc(sizeof(type)))
45#define CNEW(type)	((type *) xcalloc(sizeof(type)))
46
47/* We might as well do booleans like C++. */
48typedef unsigned char bool;
49#define false	0
50#define true	1
51
52struct Struct_Obj_Entry;
53
54typedef struct Struct_Objlist_Entry {
55    STAILQ_ENTRY(Struct_Objlist_Entry) link;
56    struct Struct_Obj_Entry *obj;
57} Objlist_Entry;
58
59typedef STAILQ_HEAD(Struct_Objlist, Struct_Objlist_Entry) Objlist;
60
61typedef struct Struct_Needed_Entry {
62    struct Struct_Needed_Entry *next;
63    struct Struct_Obj_Entry *obj;
64    unsigned long name;		/* Offset of name in string table */
65} Needed_Entry;
66
67/*
68 * Shared object descriptor.
69 *
70 * Items marked with "(%)" are dynamically allocated, and must be freed
71 * when the structure is destroyed.
72 */
73typedef struct Struct_Obj_Entry {
74    /*
75     * These two items have to be set right for compatibility with the
76     * original ElfKit crt1.o.
77     */
78    Elf_Word magic;		/* Magic number (sanity check) */
79    Elf_Word version;		/* Version number of struct format */
80
81    struct Struct_Obj_Entry *next;
82    Objlist dldags;		/* Object belongs to these dlopened DAGs (%) */
83    Objlist dagmembers;		/* DAG has these members (%) */
84    char *path;			/* Pathname of underlying file (%) */
85    unsigned long mark;		/* Set to "curmark" to avoid repeat visits */
86    int refcount;
87    int dl_refcount;		/* Number of times loaded by dlopen */
88
89    /* These items are computed by map_object() or by digest_phdr(). */
90    caddr_t mapbase;		/* Base address of mapped region */
91    size_t mapsize;		/* Size of mapped region in bytes */
92    size_t textsize;		/* Size of text segment in bytes */
93    Elf_Addr vaddrbase;		/* Base address in shared object file */
94    caddr_t relocbase;		/* Relocation constant = mapbase - vaddrbase */
95    const Elf_Dyn *dynamic;	/* Dynamic section */
96    caddr_t entry;		/* Entry point */
97    const Elf_Phdr *phdr;	/* Program header if it is mapped, else NULL */
98    size_t phsize;		/* Size of program header in bytes */
99
100    /* Items from the dynamic section. */
101    Elf_Addr *pltgot;		/* PLT or GOT, depending on architecture */
102    const Elf_Rel *rel;		/* Relocation entries */
103    unsigned long relsize;	/* Size in bytes of relocation info */
104    const Elf_Rela *rela;	/* Relocation entries with addend */
105    unsigned long relasize;	/* Size in bytes of addend relocation info */
106    const Elf_Rel *pltrel;	/* PLT relocation entries */
107    unsigned long pltrelsize;	/* Size in bytes of PLT relocation info */
108    const Elf_Rela *pltrela;	/* PLT relocation entries with addend */
109    unsigned long pltrelasize;	/* Size in bytes of PLT addend reloc info */
110    const Elf_Sym *symtab;	/* Symbol table */
111    const char *strtab;		/* String table */
112    unsigned long strsize;	/* Size in bytes of string table */
113
114    const Elf_Addr *buckets;	/* Hash table buckets array */
115    unsigned long nbuckets;	/* Number of buckets */
116    const Elf_Addr *chains;	/* Hash table chain array */
117    unsigned long nchains;	/* Number of chains */
118
119    const char *rpath;		/* Search path specified in object */
120    Needed_Entry *needed;	/* Shared objects needed by this one (%) */
121
122    void (*init)(void);		/* Initialization function to call */
123    void (*fini)(void);		/* Termination function to call */
124
125    bool mainprog;		/* True if this is the main program */
126    bool rtld;			/* True if this is the dynamic linker */
127    bool textrel;		/* True if there are relocations to text seg */
128    bool symbolic;		/* True if generated with "-Bsymbolic" */
129    bool traced;		/* Already printed in ldd trace output */
130
131    struct link_map linkmap;	/* for GDB */
132} Obj_Entry;
133
134#define RTLD_MAGIC	0xd550b87a
135#define RTLD_VERSION	1
136
137extern void _rtld_error(const char *, ...) __printflike(1, 2);
138extern Obj_Entry *map_object(int, const char *);
139extern void *xcalloc(size_t);
140extern void *xmalloc(size_t);
141extern char *xstrdup(const char *);
142extern Elf_Addr _GLOBAL_OFFSET_TABLE_[];
143
144/*
145 * Function declarations.
146 */
147int do_copy_relocations(Obj_Entry *);
148unsigned long elf_hash(const char *);
149const Elf_Sym *find_symdef(unsigned long, Obj_Entry *, const Obj_Entry **,
150  bool);
151void init_pltgot(Obj_Entry *);
152void obj_free(Obj_Entry *);
153Obj_Entry *obj_new(void);
154int reloc_non_plt(Obj_Entry *, Obj_Entry *);
155int reloc_plt(Obj_Entry *, bool);
156void _rtld_bind_start(void);
157const Elf_Sym *symlook_obj(const char *, unsigned long,
158  const Obj_Entry *, bool);
159
160#endif /* } */
161