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/* Data structure for communication from the run-time dynamic linker for

   loaded ELF shared objects.

   Copyright (C) 1995-2001, 2004, 2005, 2006 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, write to the Free

   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA

   02111-1307 USA.  */

#ifndef _LINK_H

#define _LINK_H 1

#include <features.h>

#include <elf.h>

#include <dlfcn.h>

#include <sys/types.h>

#if defined _LIBC && defined __UCLIBC_HAS_THREADS_NATIVE__

#include <tls.h>

#endif

/* We use this macro to refer to ELF types independent of the native wordsize.

   `ElfW(TYPE)' is used in place of `Elf32_TYPE' or `Elf64_TYPE'.  */

#define ElfW(type)      _ElfW (Elf, __ELF_NATIVE_CLASS, type)

#define _ElfW(e,w,t)    _ElfW_1 (e, w, _##t)

#define _ElfW_1(e,w,t)  e##w##t

#include <bits/elfclass.h>              /* Defines __ELF_NATIVE_CLASS.  */

/* Rendezvous structure used by the run-time dynamic linker to communicate

   details of shared object loading to the debugger.  If the executable's

   dynamic section has a DT_DEBUG element, the run-time linker sets that

   element's value to the address where this structure can be found.  */

struct r_debug

  {

    int r_version;              /* Version number for this protocol.  */

    struct link_map *r_map;     /* Head of the chain of loaded objects.  */

    /* This is the address of a function internal to the run-time linker,

       that will always be called when the linker begins to map in a

       library or unmap it, and again when the mapping change is complete.

       The debugger can set a breakpoint at this address if it wants to

       notice shared object mapping changes.  */

    ElfW(Addr) r_brk;

    enum

      {

        /* This state value describes the mapping change taking place when

           the `r_brk' address is called.  */

        RT_CONSISTENT,          /* Mapping change is complete.  */

        RT_ADD,                 /* Beginning to add a new object.  */

        RT_DELETE               /* Beginning to remove an object mapping.  */

      } r_state;

    ElfW(Addr) r_ldbase;        /* Base address the linker is loaded at.  */

  };

/* This is the instance of that structure used by the dynamic linker.  */

extern struct r_debug _r_debug;

/* This symbol refers to the "dynamic structure" in the `.dynamic' section

   of whatever module refers to `_DYNAMIC'.  So, to find its own

   `struct r_debug', a program could do:

     for (dyn = _DYNAMIC; dyn->d_tag != DT_NULL; ++dyn)

       if (dyn->d_tag == DT_DEBUG)

         r_debug = (struct r_debug *) dyn->d_un.d_ptr;

   */

extern ElfW(Dyn) _DYNAMIC[];

#ifdef __FDPIC__

# include <bits/elf-fdpic.h>

#endif

/* Structure describing a loaded shared object.  The `l_next' and `l_prev'

   members form a chain of all the shared objects loaded at startup.

   These data structures exist in space used by the run-time dynamic linker;

   modifying them may have disastrous results.  */

struct link_map

  {

    /* These first few members are part of the protocol with the debugger.

       This is the same format used in SVR4.  */

#ifdef __FDPIC__

    struct elf32_fdpic_loadaddr l_addr;

#else

    ElfW(Addr) l_addr;          /* Base address shared object is loaded at.  */

#endif

    char *l_name;               /* Absolute file name object was found in.  */

    ElfW(Dyn) *l_ld;            /* Dynamic section of the shared object.  */

    struct link_map *l_next, *l_prev; /* Chain of loaded objects.  */

#ifdef USE_TLS

    /* Thread-local storage related info.  */

    /* Start of the initialization image.  */

    void *l_tls_initimage;

    /* Size of the initialization image.  */

    size_t l_tls_initimage_size;

    /* Size of the TLS block.  */

    size_t l_tls_blocksize;

    /* Alignment requirement of the TLS block.  */

    size_t l_tls_align;

    /* Offset of first byte module alignment.  */

    size_t l_tls_firstbyte_offset;

# ifndef NO_TLS_OFFSET

#  define NO_TLS_OFFSET 0

# endif

    /* For objects present at startup time: offset in the static TLS block.  */

    ptrdiff_t l_tls_offset;

    /* Index of the module in the dtv array.  */

    size_t l_tls_modid;

    /* Nonzero if _dl_init_static_tls should be called for this module */

    unsigned int l_need_tls_init:1;

#endif

  };

#ifdef __USE_GNU

#if 0

/* Version numbers for la_version handshake interface.  */

#define LAV_CURRENT     1

/* Activity types signaled through la_activity.  */

enum

  {

    LA_ACT_CONSISTENT,          /* Link map consistent again.  */

    LA_ACT_ADD,                 /* New object will be added.  */

    LA_ACT_DELETE               /* Objects will be removed.  */

  };

/* Values representing origin of name for dynamic loading.  */

enum

  {

    LA_SER_ORIG = 0x01,         /* Original name.  */

    LA_SER_LIBPATH = 0x02,      /* Directory from LD_LIBRARY_PATH.  */

    LA_SER_RUNPATH = 0x04,      /* Directory from RPATH/RUNPATH.  */

    LA_SER_CONFIG = 0x08,       /* Found through ldconfig.  */

    LA_SER_DEFAULT = 0x40,      /* Default directory.  */

    LA_SER_SECURE = 0x80        /* Unused.  */

  };

/* Values for la_objopen return value.  */

enum

  {

    LA_FLG_BINDTO = 0x01,       /* Audit symbols bound to this object.  */

    LA_FLG_BINDFROM = 0x02      /* Audit symbols bound from this object.  */

  };

/* Values for la_symbind flags parameter.  */

enum

  {

    LA_SYMB_NOPLTENTER = 0x01,  /* la_pltenter will not be called.  */

    LA_SYMB_NOPLTEXIT = 0x02,   /* la_pltexit will not be called.  */

    LA_SYMB_STRUCTCALL = 0x04,  /* Return value is a structure.  */

    LA_SYMB_DLSYM = 0x08,       /* Binding due to dlsym call.  */

    LA_SYMB_ALTVALUE = 0x10     /* Value has been changed by a previous

                                   la_symbind call.  */

  };

#endif

struct dl_phdr_info

  {

#ifdef __FDPIC__

    struct elf32_fdpic_loadaddr dlpi_addr;

#else

    ElfW(Addr) dlpi_addr;

#endif

    const char *dlpi_name;

    const ElfW(Phdr) *dlpi_phdr;

    ElfW(Half) dlpi_phnum;

#if 0

    /* Note: Following members were introduced after the first

       version of this structure was available.  Check the SIZE

       argument passed to the dl_iterate_phdr callback to determine

       whether or not each later member is available.  */

    /* Incremented when a new object may have been added.  */

    unsigned long long int dlpi_adds;

    /* Incremented when an object may have been removed.  */

    unsigned long long int dlpi_subs;

    /* If there is a PT_TLS segment, its module ID as used in

       TLS relocations, else zero.  */

    size_t dlpi_tls_modid;

    /* The address of the calling thread's instance of this module's

       PT_TLS segment, if it has one and it has been allocated

       in the calling thread, otherwise a null pointer.  */

    void *dlpi_tls_data;

#endif

  };

__BEGIN_DECLS

extern int dl_iterate_phdr (int (*__callback) (struct dl_phdr_info *,

                                               size_t, void *),

                            void *__data);

#if 0

/* Prototypes for the ld.so auditing interfaces.  These are not

   defined anywhere in ld.so but instead have to be provided by the

   auditing DSO.  */

extern unsigned int la_version (unsigned int __version);

extern void la_activity (uintptr_t *__cookie, unsigned int __flag);

extern char *la_objsearch (const char *__name, uintptr_t *__cookie,

                           unsigned int __flag);

extern unsigned int la_objopen (struct link_map *__map, Lmid_t __lmid,

                                uintptr_t *__cookie);

extern void la_preinit (uintptr_t *__cookie);

extern uintptr_t la_symbind32 (Elf32_Sym *__sym, unsigned int __ndx,

                               uintptr_t *__refcook, uintptr_t *__defcook,

                               unsigned int *__flags, const char *__symname);

extern uintptr_t la_symbind64 (Elf64_Sym *__sym, unsigned int __ndx,

                               uintptr_t *__refcook, uintptr_t *__defcook,

                               unsigned int *__flags, const char *__symname);

extern unsigned int la_objclose (uintptr_t *__cookie);

#endif

__END_DECLS

#endif

#endif /* link.h */