xref: /src/libexec/ld.elf_so/rtld.h

/*	$NetBSD: rtld.h,v 1.5 1998/07/01 20:42:47 tv Exp $	*/

/*
 * Copyright 1996 John D. Polstra.
 * Copyright 1996 Matt Thomas <matt (at) 3am-software.com>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by John Polstra.
 * 4. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef RTLD_H /* { */
#define RTLD_H 1

#include <stddef.h>
#include <sys/param.h>
#include <sys/types.h>
#include <sys/exec_elf.h>
#include "rtldenv.h"
#include "link.h"

#define	RTLD_DEFAULT_LIBRARY_PATH	"/usr/lib:/usr/local/lib"

#if 0
#define SVR4_LIBDIR	"/usr/lib"
#endif

#define LIBDIRLEN	(sizeof LIBDIR - 1)
#define SVR4_LIBDIRLEN	(sizeof SVR4_LIBDIR - 1)

#ifndef	PAGESIZE
#define PAGESIZE	CLBYTES
#endif
#define round_down(x)	((x) & ~(PAGESIZE-1))
#define round_up(x)	round_down((x) + PAGESIZE - 1)

#define NEW(type)	((type *) xmalloc(sizeof(type)))
#define CNEW(type)	((type *) xcalloc(sizeof(type)))

/*
 * C++ has mandated the use of the following keywords for its new boolean
 * type.  We might as well follow their lead.
 */
typedef unsigned char bool;
#define false	0
#define true	1

struct Struct_Obj_Entry;

typedef struct Struct_Needed_Entry {
    struct Struct_Needed_Entry *next;
    struct Struct_Obj_Entry *obj;
    unsigned long name;		/* Offset of name in string table */
} Needed_Entry;

typedef struct _rtld_search_path_t {
    struct _rtld_search_path_t *sp_next;
    const char *sp_path;
    size_t sp_pathlen;
} Search_Path;

/*
 * Shared object descriptor.
 *
 * Items marked with "(%)" are dynamically allocated, and must be freed
 * when the structure is destroyed.
 */

#define RTLD_MAGIC	0xd550b87a
#define RTLD_VERSION	1

typedef struct Struct_Obj_Entry {
    Elf32_Word magic;		/* Magic number (sanity check) */
    Elf32_Word version;		/* Version number of struct format */

    struct Struct_Obj_Entry *next;
    char *path;			/* Pathname of underlying file (%) */
    int refcount;
    int dl_refcount;		/* Number of times loaded by dlopen */

    /* These items are computed by map_object() or by digest_phdr(). */
    caddr_t mapbase;		/* Base address of mapped region */
    size_t mapsize;		/* Size of mapped region in bytes */
    size_t textsize;		/* Size of text segment in bytes */
    Elf_Addr vaddrbase;		/* Base address in shared object file */
    caddr_t relocbase;		/* Relocation constant = mapbase - vaddrbase */
    Elf_Dyn *dynamic;		/* Dynamic section */
    caddr_t entry;		/* Entry point */
    const Elf_Phdr *phdr;	/* Program header if it is mapped, else NULL */
    size_t phsize;		/* Size of program header in bytes */

    /* Items from the dynamic section. */
    Elf_Addr *pltgot;		/* PLTGOT table */
    const Elf_Rel *rel;		/* Relocation entries */
    const Elf_Rel *rellim;	/* Limit of Relocation entries */
    const Elf_RelA *rela;	/* Relocation entries */
    const Elf_RelA *relalim;	/* Limit of Relocation entries */
    const Elf_Rel *pltrel;	/* PLT relocation entries */
    const Elf_Rel *pltrellim;	/* Limit of PLT relocation entries */
    const Elf_RelA *pltrela;	/* PLT relocation entries */
    const Elf_RelA *pltrelalim;	/* Limit of PLT relocation entries */
    const Elf_Sym *symtab;	/* Symbol table */
    const char *strtab;		/* String table */
    unsigned long strsize;	/* Size in bytes of string table */
#if defined(__mips__)
    Elf_Word local_gotno;	/* Number of local GOT entries */
    Elf_Word symtabno;		/* Number of dynamic symbols */
    Elf_Word gotsym;		/* First dynamic symbol in GOT */
#endif

    const Elf_Word *buckets;	/* Hash table buckets array */
    unsigned long nbuckets;	/* Number of buckets */
    const Elf_Word *chains;	/* Hash table chain array */
    unsigned long nchains;	/* Number of chains */

    Search_Path *rpaths;	/* Search path specified in object */
    Needed_Entry *needed;	/* Shared objects needed by this one (%) */

    void (*init)(void);		/* Initialization function to call */
    void (*fini)(void);		/* Termination function to call */

    /* Entry points for dlopen() and friends. */
    void *(*dlopen)(const char *, int);
    void *(*dlsym)(void *, const char *);
    char *(*dlerror)(void);
    int (*dlclose)(void *);

    int mainprog : 1;		/* True if this is the main program */
    int rtld : 1;		/* True if this is the dynamic linker */
    int textrel : 1;		/* True if there are relocations to text seg */
    int symbolic : 1;		/* True if generated with "-Bsymbolic" */
    int printed : 1;		/* True if ldd has printed it */

    struct link_map linkmap;	/* for GDB */
} Obj_Entry;

extern struct r_debug _rtld_debug;
extern Obj_Entry *_rtld_objlist;
extern Obj_Entry **_rtld_objtail;
extern Obj_Entry _rtld_objself;
extern Search_Path *_rtld_paths;
extern bool _rtld_trust;
extern const char *_rtld_error_message;

/* rtld_start.S */
extern void _rtld_bind_start(void);

/* rtld.c */

extern void _rtld_error(const char *, ...);
extern void _rtld_die(void);

extern char *_rtld_dlerror(void);
extern void *_rtld_dlopen(const char *, int);
extern void *_rtld_dlsym(void *, const char *);
extern int _rtld_dlclose(void *);

extern void _rtld_debug_state(void);

extern void _rtld_linkmap_add(Obj_Entry *);
extern void _rtld_linkmap_delete(Obj_Entry *);

/* headers.c */

extern void _rtld_digest_dynamic(Obj_Entry *);
extern Obj_Entry *_rtld_digest_phdr(const Elf_Phdr *, int, caddr_t);

/* load.c */

extern Obj_Entry *_rtld_load_object(char *path);
extern int _rtld_load_needed_objects(Obj_Entry *);

/* path.c */

extern void _rtld_add_paths(Search_Path **, const char *);

/* reloc.c */
extern int _rtld_do_copy_relocations(const Obj_Entry *);
extern caddr_t _rtld_bind(const Obj_Entry *, Elf_Word);
extern int _rtld_relocate_objects(Obj_Entry *, bool);

/* search.c */

extern char *_rtld_find_library(const char *, const Obj_Entry *);

/* symbol.c */
extern unsigned long _rtld_elf_hash(const char *);
extern const Elf_Sym *_rtld_symlook_obj(const char *, unsigned long,
    const Obj_Entry *, bool);
extern const Elf_Sym *_rtld_find_symdef(const Obj_Entry *, Elf_Word,
    const char *, const Obj_Entry *, const Obj_Entry **, bool);

/* map_object.c */
extern Obj_Entry *_rtld_map_object(const char *, int);

#if defined(__mips__)
/* mips_reloc.c */
extern void _rtld_relocate_mips_got(Obj_Entry *);
extern caddr_t _rtld_bind_mips (Elf_Word, Elf_Addr, Elf_Addr, Elf_Addr);
#endif

#endif /* } */