freebsd-skq/libexec/rtld-elf/rtld.h
Konstantin Belousov 6d7610d75a Add support for GNU RELRO.
Submitted by:	John Marino <draco marino st>
MFC after:	2 weeks
2012-01-30 19:52:17 +00:00

348 lines
13 KiB
C

/*-
* Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
* 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.
*
* 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.
*
* $FreeBSD$
*/
#ifndef RTLD_H /* { */
#define RTLD_H 1
#include <machine/elf.h>
#include <sys/types.h>
#include <sys/queue.h>
#include <elf-hints.h>
#include <link.h>
#include <stdarg.h>
#include <setjmp.h>
#include <stddef.h>
#include "rtld_lock.h"
#include "rtld_machdep.h"
#ifdef COMPAT_32BIT
#undef STANDARD_LIBRARY_PATH
#undef _PATH_ELF_HINTS
#define _PATH_ELF_HINTS "/var/run/ld-elf32.so.hints"
/* For running 32 bit binaries */
#define STANDARD_LIBRARY_PATH "/lib32:/usr/lib32"
#define LD_ "LD_32_"
#endif
#ifndef STANDARD_LIBRARY_PATH
#define STANDARD_LIBRARY_PATH "/lib:/usr/lib"
#endif
#ifndef LD_
#define LD_ "LD_"
#endif
#define NEW(type) ((type *) xmalloc(sizeof(type)))
#define CNEW(type) ((type *) xcalloc(sizeof(type)))
/* We might as well do booleans like C++. */
typedef unsigned char bool;
#define false 0
#define true 1
extern size_t tls_last_offset;
extern size_t tls_last_size;
extern size_t tls_static_space;
extern int tls_dtv_generation;
extern int tls_max_index;
struct stat;
struct Struct_Obj_Entry;
/* Lists of shared objects */
typedef struct Struct_Objlist_Entry {
STAILQ_ENTRY(Struct_Objlist_Entry) link;
struct Struct_Obj_Entry *obj;
} Objlist_Entry;
typedef STAILQ_HEAD(Struct_Objlist, Struct_Objlist_Entry) Objlist;
/* Types of init and fini functions */
typedef void (*InitFunc)(void);
/* Lists of shared object dependencies */
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 Struct_Name_Entry {
STAILQ_ENTRY(Struct_Name_Entry) link;
char name[1];
} Name_Entry;
/* Lock object */
typedef struct Struct_LockInfo {
void *context; /* Client context for creating locks */
void *thelock; /* The one big lock */
/* Debugging aids. */
volatile int rcount; /* Number of readers holding lock */
volatile int wcount; /* Number of writers holding lock */
/* Methods */
void *(*lock_create)(void *context);
void (*rlock_acquire)(void *lock);
void (*wlock_acquire)(void *lock);
void (*rlock_release)(void *lock);
void (*wlock_release)(void *lock);
void (*lock_destroy)(void *lock);
void (*context_destroy)(void *context);
} LockInfo;
typedef struct Struct_Ver_Entry {
Elf_Word hash;
unsigned int flags;
const char *name;
const char *file;
} Ver_Entry;
#define VER_INFO_HIDDEN 0x01
/*
* Shared object descriptor.
*
* Items marked with "(%)" are dynamically allocated, and must be freed
* when the structure is destroyed.
*
* CAUTION: It appears that the JDK port peeks into these structures.
* It looks at "next" and "mapbase" at least. Don't add new members
* near the front, until this can be straightened out.
*/
typedef struct Struct_Obj_Entry {
/*
* These two items have to be set right for compatibility with the
* original ElfKit crt1.o.
*/
Elf_Size magic; /* Magic number (sanity check) */
Elf_Size version; /* Version number of struct format */
struct Struct_Obj_Entry *next;
char *path; /* Pathname of underlying file (%) */
char *origin_path; /* Directory path of origin 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 */
const 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 */
const char *interp; /* Pathname of the interpreter, if any */
Elf_Word stack_flags;
/* TLS information */
int tlsindex; /* Index in DTV for this module */
void *tlsinit; /* Base address of TLS init block */
size_t tlsinitsize; /* Size of TLS init block for this module */
size_t tlssize; /* Size of TLS block for this module */
size_t tlsoffset; /* Offset of static TLS block for this module */
size_t tlsalign; /* Alignment of static TLS block */
caddr_t relro_page;
size_t relro_size;
/* Items from the dynamic section. */
Elf_Addr *pltgot; /* PLT or GOT, depending on architecture */
const Elf_Rel *rel; /* Relocation entries */
unsigned long relsize; /* Size in bytes of relocation info */
const Elf_Rela *rela; /* Relocation entries with addend */
unsigned long relasize; /* Size in bytes of addend relocation info */
const Elf_Rel *pltrel; /* PLT relocation entries */
unsigned long pltrelsize; /* Size in bytes of PLT relocation info */
const Elf_Rela *pltrela; /* PLT relocation entries with addend */
unsigned long pltrelasize; /* Size in bytes of PLT addend reloc info */
const Elf_Sym *symtab; /* Symbol table */
const char *strtab; /* String table */
unsigned long strsize; /* Size in bytes of string table */
#ifdef __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_Verneed *verneed; /* Required versions. */
Elf_Word verneednum; /* Number of entries in verneed table */
const Elf_Verdef *verdef; /* Provided versions. */
Elf_Word verdefnum; /* Number of entries in verdef table */
const Elf_Versym *versyms; /* Symbol versions table */
const Elf_Hashelt *buckets; /* Hash table buckets array */
unsigned long nbuckets; /* Number of buckets */
const Elf_Hashelt *chains; /* Hash table chain array */
unsigned long nchains; /* Number of chains */
char *rpath; /* Search path specified in object */
Needed_Entry *needed; /* Shared objects needed by this one (%) */
Needed_Entry *needed_filtees;
Needed_Entry *needed_aux_filtees;
STAILQ_HEAD(, Struct_Name_Entry) names; /* List of names for this object we
know about. */
Ver_Entry *vertab; /* Versions required /defined by this object */
int vernum; /* Number of entries in vertab */
Elf_Addr init; /* Initialization function to call */
Elf_Addr fini; /* Termination function to call */
bool mainprog : 1; /* True if this is the main program */
bool rtld : 1; /* True if this is the dynamic linker */
bool textrel : 1; /* True if there are relocations to text seg */
bool symbolic : 1; /* True if generated with "-Bsymbolic" */
bool bind_now : 1; /* True if all relocations should be made first */
bool traced : 1; /* Already printed in ldd trace output */
bool jmpslots_done : 1; /* Already have relocated the jump slots */
bool init_done : 1; /* Already have added object to init list */
bool tls_done : 1; /* Already allocated offset for static TLS */
bool phdr_alloc : 1; /* Phdr is allocated and needs to be freed. */
bool z_origin : 1; /* Process rpath and soname tokens */
bool z_nodelete : 1; /* Do not unload the object and dependencies */
bool z_noopen : 1; /* Do not load on dlopen */
bool z_loadfltr : 1; /* Immediately load filtees */
bool ref_nodel : 1; /* Refcount increased to prevent dlclose */
bool init_scanned: 1; /* Object is already on init list. */
bool on_fini_list: 1; /* Object is already on fini list. */
bool dag_inited : 1; /* Object has its DAG initialized. */
bool filtees_loaded : 1; /* Filtees loaded */
bool irelative : 1; /* Object has R_MACHDEP_IRELATIVE relocs */
bool gnu_ifunc : 1; /* Object has references to STT_GNU_IFUNC */
struct link_map linkmap; /* For GDB and dlinfo() */
Objlist dldags; /* Object belongs to these dlopened DAGs (%) */
Objlist dagmembers; /* DAG has these members (%) */
dev_t dev; /* Object's filesystem's device */
ino_t ino; /* Object's inode number */
void *priv; /* Platform-dependent */
} Obj_Entry;
#define RTLD_MAGIC 0xd550b87a
#define RTLD_VERSION 1
#define RTLD_STATIC_TLS_EXTRA 128
/* Flags to be passed into symlook_ family of functions. */
#define SYMLOOK_IN_PLT 0x01 /* Lookup for PLT symbol */
#define SYMLOOK_DLSYM 0x02 /* Return newest versioned symbol. Used by
dlsym. */
/* Flags for load_object(). */
#define RTLD_LO_NOLOAD 0x01 /* dlopen() specified RTLD_NOLOAD. */
#define RTLD_LO_DLOPEN 0x02 /* Load_object() called from dlopen(). */
#define RTLD_LO_TRACE 0x04 /* Only tracing. */
#define RTLD_LO_NODELETE 0x08 /* Loaded object cannot be closed. */
#define RTLD_LO_FILTEES 0x10 /* Loading filtee. */
/*
* Symbol cache entry used during relocation to avoid multiple lookups
* of the same symbol.
*/
typedef struct Struct_SymCache {
const Elf_Sym *sym; /* Symbol table entry */
const Obj_Entry *obj; /* Shared object which defines it */
} SymCache;
/*
* This structure provides a reentrant way to keep a list of objects and
* check which ones have already been processed in some way.
*/
typedef struct Struct_DoneList {
const Obj_Entry **objs; /* Array of object pointers */
unsigned int num_alloc; /* Allocated size of the array */
unsigned int num_used; /* Number of array slots used */
} DoneList;
struct Struct_RtldLockState {
int lockstate;
sigjmp_buf env;
};
/*
* The pack of arguments and results for the symbol lookup functions.
*/
typedef struct Struct_SymLook {
const char *name;
unsigned long hash;
const Ver_Entry *ventry;
int flags;
const Obj_Entry *defobj_out;
const Elf_Sym *sym_out;
struct Struct_RtldLockState *lockstate;
} SymLook;
extern void _rtld_error(const char *, ...) __printflike(1, 2);
extern Obj_Entry *map_object(int, const char *, const struct stat *);
extern void *xcalloc(size_t);
extern void *xmalloc(size_t);
extern char *xstrdup(const char *);
extern Elf_Addr _GLOBAL_OFFSET_TABLE_[];
extern Elf_Sym sym_zero; /* For resolving undefined weak refs. */
extern void dump_relocations (Obj_Entry *);
extern void dump_obj_relocations (Obj_Entry *);
extern void dump_Elf_Rel (Obj_Entry *, const Elf_Rel *, u_long);
extern void dump_Elf_Rela (Obj_Entry *, const Elf_Rela *, u_long);
/*
* Function declarations.
*/
unsigned long elf_hash(const char *);
const Elf_Sym *find_symdef(unsigned long, const Obj_Entry *,
const Obj_Entry **, int, SymCache *, struct Struct_RtldLockState *);
void init_pltgot(Obj_Entry *);
void lockdflt_init(void);
void obj_free(Obj_Entry *);
Obj_Entry *obj_new(void);
void _rtld_bind_start(void);
void *rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def);
void symlook_init(SymLook *, const char *);
int symlook_obj(SymLook *, const Obj_Entry *);
void *tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset);
void *allocate_tls(Obj_Entry *, void *, size_t, size_t);
void free_tls(void *, size_t, size_t);
void *allocate_module_tls(int index);
bool allocate_tls_offset(Obj_Entry *obj);
void free_tls_offset(Obj_Entry *obj);
const Ver_Entry *fetch_ventry(const Obj_Entry *obj, unsigned long);
/*
* MD function declarations.
*/
int do_copy_relocations(Obj_Entry *);
int reloc_non_plt(Obj_Entry *, Obj_Entry *, struct Struct_RtldLockState *);
int reloc_plt(Obj_Entry *);
int reloc_jmpslots(Obj_Entry *, struct Struct_RtldLockState *);
int reloc_iresolve(Obj_Entry *, struct Struct_RtldLockState *);
int reloc_gnu_ifunc(Obj_Entry *, struct Struct_RtldLockState *);
void allocate_initial_tls(Obj_Entry *);
#endif /* } */