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

   loaded ELF shared objects.

   Copyright (C) 1995-1999, 2000, 2001 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>

#define DT_THISPROCNUM 0

/* 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 <sys/elfclass.h>               /* Defines __ELF_NATIVE_CLASS.  */

#include <sys/link.h>

#include <dl-lookupcfg.h>

/* 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[];

/* Some internal data structures of the dynamic linker used in the

   linker map.  We only provide forward declarations.  */

struct libname_list;

struct r_found_version;

struct r_search_path_elem;

/* Forward declaration.  */

struct link_map;

/* Structure to describe a single list of scope elements.  The lookup

   functions get passed an array of pointers to such structures.  */

struct r_scope_elem

{

  /* Array of maps for the scope.  */

  struct link_map **r_list;

  /* Number of entries in the scope.  */

  unsigned int r_nlist;

};

/* Structure to record search path and allocation mechanism.  */

struct r_search_path_struct

  {

    struct r_search_path_elem **dirs;

    int malloced;

  };

/* 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.

   This data structure might change in future, if necessary.  User-level

   programs must avoid defining objects of this type.  */

struct link_map

  {

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

       This is the same format used in SVR4.  */

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

    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.  */

    /* All following members are internal to the dynamic linker.

       They may change without notice.  */

    struct libname_list *l_libname;

    /* Indexed pointers to dynamic section.

       [0,DT_NUM) are indexed by the processor-independent tags.

       [DT_NUM,DT_NUM+DT_THISPROCNUM) are indexed by the tag minus DT_LOPROC.

       [DT_NUM+DT_THISPROCNUM,DT_NUM+DT_THISPROCNUM+DT_EXTRANUM) are indexed

       by DT_EXTRATAGIDX(tagvalue) and

       [DT_NUM+DT_THISPROCNUM+DT_VERSIONTAGNUM,

        DT_NUM+DT_THISPROCNUM+DT_VERSIONTAGNUM+DT_EXTRANUM)

       are indexed by DT_EXTRATAGIDX(tagvalue) (see <elf.h>).  */

    ElfW(Dyn) *l_info[DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGNUM

                     + DT_EXTRANUM];

    const ElfW(Phdr) *l_phdr;   /* Pointer to program header table in core.  */

    ElfW(Addr) l_entry;         /* Entry point location.  */

    ElfW(Half) l_phnum;         /* Number of program header entries.  */

    ElfW(Half) l_ldnum; /* Number of dynamic segment entries.  */

    /* Array of DT_NEEDED dependencies and their dependencies, in

       dependency order for symbol lookup (with and without

       duplicates).  There is no entry before the dependencies have

       been loaded.  */

    struct r_scope_elem l_searchlist;

    /* We need a special searchlist to process objects marked with

       DT_SYMBOLIC.  */

    struct r_scope_elem l_symbolic_searchlist;

    /* Dependent object that first caused this object to be loaded.  */

    struct link_map *l_loader;

    /* Symbol hash table.  */

    Elf_Symndx l_nbuckets;

    const Elf_Symndx *l_buckets, *l_chain;

    unsigned int l_opencount;   /* Reference count for dlopen/dlclose.  */

    enum                        /* Where this object came from.  */

      {

        lt_executable,          /* The main executable program.  */

        lt_library,             /* Library needed by main executable.  */

        lt_loaded               /* Extra run-time loaded shared object.  */

      } l_type:2;

    unsigned int l_relocated:1; /* Nonzero if object's relocations done.  */

    unsigned int l_init_called:1; /* Nonzero if DT_INIT function called.  */

    unsigned int l_global:1;    /* Nonzero if object in _dl_global_scope.  */

    unsigned int l_reserved:2;  /* Reserved for internal use.  */

    unsigned int l_phdr_allocated:1; /* Nonzero if the data structure pointed

                                        to by `l_phdr' is allocated.  */

    unsigned int l_soname_added:1; /* Nonzero if the SONAME is for sure in

                                      the l_libname list.  */

    unsigned int l_faked:1;     /* Nonzero if this is a faked descriptor

                                   without associated file.  */

    /* Array with version names.  */

    unsigned int l_nversions;

    struct r_found_version *l_versions;

    /* Collected information about own RPATH directories.  */

    struct r_search_path_struct l_rpath_dirs;

    /* Collected results of relocation while profiling.  */

    ElfW(Addr) *l_reloc_result;

    /* Pointer to the version information if available.  */

    ElfW(Versym) *l_versyms;

    /* String specifying the path where this object was found.  */

    const char *l_origin;

    /* Start and finish of memory map for this object.  l_map_start

       need not be the same as l_addr.  */

    ElfW(Addr) l_map_start, l_map_end;

    /* Default array for 'l_scope'.  */

    struct r_scope_elem *l_scope_mem[4];

    /* Size of array allocated for 'l_scope'.  */

    size_t l_scope_max;

    /* This is an array defining the lookup scope for this link map.

       There are at most three different scope lists.  */

    struct r_scope_elem **l_scope;

    /* A similar array, this time only with the local scope.  This is

       used occasionally.  */

    struct r_scope_elem *l_local_scope[2];

    /* This information is kept to check for sure whether a shared

       object is the same as one already loaded.  */

    dev_t l_dev;

    ino64_t l_ino;

    /* Collected information about own RUNPATH directories.  */

    struct r_search_path_struct l_runpath_dirs;

    /* List of object in order of the init and fini calls.  */

    struct link_map **l_initfini;

    /* List of the dependencies introduced through symbol binding.  */

    unsigned int l_reldepsmax;

    unsigned int l_reldepsact;

    struct link_map **l_reldeps;

    /* Various flag words.  */

    ElfW(Word) l_feature_1;

    ElfW(Word) l_flags_1;

    /* Temporarily used in `dl_close'.  */

    unsigned int l_idx;

    struct link_map_machine l_mach;

    struct

    {

      const ElfW(Sym) *sym;

      int type_class;

#ifdef DL_LOOKUP_RETURNS_MAP

      struct link_map *value;

#else

      ElfW(Addr) value;

#endif

      const ElfW(Sym) *ret;

    } l_lookup_cache;

  };

struct dl_phdr_info

  {

    ElfW(Addr) dlpi_addr;

    const char *dlpi_name;

    const ElfW(Phdr) *dlpi_phdr;

    ElfW(Half) dlpi_phnum;

  };

extern int dl_iterate_phdr (int (*callback) (struct dl_phdr_info *info,

                                             size_t size, void *data),

                            void *data);

extern int __dl_iterate_phdr (int (*callback) (struct dl_phdr_info *info,

                                               size_t size, void *data),

                              void *data);

#endif /* link.h */