rtld.h revision 34192 
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 *      $Id: rtld.h,v 1.3 1998/03/06 14:00:09 jdp Exp $
26 */
27
28#ifndef RTLD_H /* { */
29#define RTLD_H 1
30
31#include <sys/types.h>
32
33#include <elf.h>
34#include <stddef.h>
35
36#ifndef STANDARD_LIBRARY_PATH
37#define STANDARD_LIBRARY_PATH	"/usr/lib/elf:/usr/lib"
38#endif
39
40#define NEW(type)	((type *) xmalloc(sizeof(type)))
41#define CNEW(type)	((type *) xcalloc(sizeof(type)))
42
43/* We might as well do booleans like C++. */
44typedef unsigned char bool;
45#define false	0
46#define true	1
47
48struct Struct_Obj_Entry;
49
50typedef struct Struct_Needed_Entry {
51    struct Struct_Needed_Entry *next;
52    struct Struct_Obj_Entry *obj;
53    unsigned long name;		/* Offset of name in string table */
54} Needed_Entry;
55
56/*
57 * Shared object descriptor.
58 *
59 * Items marked with "(%)" are dynamically allocated, and must be freed
60 * when the structure is destroyed.
61 */
62typedef struct Struct_Obj_Entry {
63    /*
64     * These two items have to be set right for compatibility with the
65     * original ElfKit crt1.o.
66     */
67    Elf32_Word magic;		/* Magic number (sanity check) */
68    Elf32_Word version;		/* Version number of struct format */
69
70    struct Struct_Obj_Entry *next;
71    char *path;			/* Pathname of underlying file (%) */
72    int refcount;
73    int dl_refcount;		/* Number of times loaded by dlopen */
74
75    /* These items are computed by map_object() or by digest_phdr(). */
76    caddr_t mapbase;		/* Base address of mapped region */
77    size_t mapsize;		/* Size of mapped region in bytes */
78    size_t textsize;		/* Size of text segment in bytes */
79    Elf32_Addr vaddrbase;	/* Base address in shared object file */
80    caddr_t relocbase;		/* Relocation constant = mapbase - vaddrbase */
81    const Elf32_Dyn *dynamic;	/* Dynamic section */
82    caddr_t entry;		/* Entry point */
83    const Elf32_Phdr *phdr;	/* Program header if it is mapped, else NULL */
84    size_t phsize;		/* Size of program header in bytes */
85
86    /* Items from the dynamic section. */
87    Elf32_Addr *got;		/* GOT table */
88    const Elf32_Rel *rel;	/* Relocation entries */
89    unsigned long relsize;	/* Size in bytes of relocation info */
90    const Elf32_Rel *pltrel;	/* PLT relocation entries */
91    unsigned long pltrelsize;	/* Size in bytes of PLT relocation info */
92    const Elf32_Sym *symtab;	/* Symbol table */
93    const char *strtab;		/* String table */
94    unsigned long strsize;	/* Size in bytes of string table */
95
96    const Elf32_Word *buckets;	/* Hash table buckets array */
97    unsigned long nbuckets;	/* Number of buckets */
98    const Elf32_Word *chains;	/* Hash table chain array */
99    unsigned long nchains;	/* Number of chains */
100
101    const char *rpath;		/* Search path specified in object */
102    Needed_Entry *needed;	/* Shared objects needed by this one (%) */
103
104    void (*init)(void);		/* Initialization function to call */
105    void (*fini)(void);		/* Termination function to call */
106
107    bool mainprog;		/* True if this is the main program */
108    bool rtld;			/* True if this is the dynamic linker */
109    bool textrel;		/* True if there are relocations to text seg */
110    bool symbolic;		/* True if generated with "-Bsymbolic" */
111} Obj_Entry;
112
113#define RTLD_MAGIC	0xd550b87a
114#define RTLD_VERSION	1
115
116extern void _rtld_error(const char *, ...);
117extern Obj_Entry *map_object(int);
118extern void *xcalloc(size_t);
119extern void *xmalloc(size_t);
120extern char *xstrdup(const char *);
121
122#endif /* } */
123