454 lines
16 KiB
C
454 lines
16 KiB
C
/* $NetBSD: rtld.h,v 1.106 2011/06/25 05:45:12 nonaka Exp $ */
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/*
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* Copyright 1996 John D. Polstra.
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* Copyright 1996 Matt Thomas <matt@3am-software.com>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by John Polstra.
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* 4. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef RTLD_H
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#define RTLD_H
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#include <dlfcn.h>
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#include <signal.h>
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#include <stdbool.h>
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#include <stddef.h>
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#include <sys/param.h>
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#include <sys/types.h>
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#include <sys/queue.h>
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#include <sys/exec_elf.h>
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#include <sys/tls.h>
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#include "rtldenv.h"
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#include "link.h"
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#if defined(_RTLD_SOURCE)
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#ifndef RTLD_DEFAULT_LIBRARY_PATH
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#define RTLD_DEFAULT_LIBRARY_PATH "/usr/lib"
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#endif
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#define _PATH_LD_HINTS "/etc/ld.so.conf"
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extern size_t _rtld_pagesz;
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#define round_down(x) ((x) & ~(_rtld_pagesz - 1))
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#define round_up(x) round_down((x) + _rtld_pagesz - 1)
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#define NEW(type) ((type *) xmalloc(sizeof(type)))
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#define CNEW(type) ((type *) xcalloc(sizeof(type)))
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/*
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* Fill in a DoneList with an allocation large enough to hold all of
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* the currently-loaded objects. Keep this in a macro since it calls
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* alloca and we want that to occur within the scope of the caller.
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*/
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#define _rtld_donelist_init(dlp) \
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((dlp)->num_alloc = _rtld_objcount, \
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(dlp)->objs = alloca((dlp)->num_alloc * sizeof((dlp)->objs[0])), \
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assert((dlp)->objs != NULL), \
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(dlp)->num_used = 0)
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#endif /* _RTLD_SOURCE */
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/*
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* C++ has mandated the use of the following keywords for its new boolean
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* type. We might as well follow their lead.
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*/
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struct Struct_Obj_Entry;
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typedef struct Struct_Objlist_Entry {
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SIMPLEQ_ENTRY(Struct_Objlist_Entry) link;
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struct Struct_Obj_Entry *obj;
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} Objlist_Entry;
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typedef SIMPLEQ_HEAD(Struct_Objlist, Struct_Objlist_Entry) Objlist;
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typedef struct Struct_Name_Entry {
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STAILQ_ENTRY(Struct_Name_Entry) link;
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char name[1];
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} Name_Entry;
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typedef struct Struct_Needed_Entry {
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struct Struct_Needed_Entry *next;
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struct Struct_Obj_Entry *obj;
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unsigned long name; /* Offset of name in string table */
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} Needed_Entry;
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typedef struct _rtld_search_path_t {
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struct _rtld_search_path_t *sp_next;
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const char *sp_path;
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size_t sp_pathlen;
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} Search_Path;
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typedef struct Struct_Ver_Entry {
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Elf_Word hash;
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u_int flags;
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const char *name;
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const char *file;
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} Ver_Entry;
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/* Ver_Entry.flags */
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#define VER_INFO_HIDDEN 0x01
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#define RTLD_MAX_ENTRY 10
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#define RTLD_MAX_LIBRARY 4
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#define RTLD_MAX_CTL 2
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typedef struct _rtld_library_xform_t {
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struct _rtld_library_xform_t *next;
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char *name;
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const char *ctlname;
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struct {
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char *value;
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char *library[RTLD_MAX_LIBRARY];
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} entry[RTLD_MAX_ENTRY];
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} Library_Xform;
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/*
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* Shared object descriptor.
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*
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* Items marked with "(%)" are dynamically allocated, and must be freed
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* when the structure is destroyed.
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*
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* The layout of this structure needs to be preserved because pre-2.0 binaries
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* hard-coded the location of dlopen() and friends.
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*/
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#define RTLD_MAGIC 0xd550b87a
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#define RTLD_VERSION 1
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typedef struct Struct_Obj_Entry {
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Elf32_Word magic; /* Magic number (sanity check) */
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Elf32_Word version; /* Version number of struct format */
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struct Struct_Obj_Entry *next;
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char *path; /* Pathname of underlying file (%) */
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int refcount;
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int dl_refcount; /* Number of times loaded by dlopen */
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/* These items are computed by map_object() or by digest_phdr(). */
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caddr_t mapbase; /* Base address of mapped region */
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size_t mapsize; /* Size of mapped region in bytes */
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size_t textsize; /* Size of text segment in bytes */
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Elf_Addr vaddrbase; /* Base address in shared object file */
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caddr_t relocbase; /* Reloc const = mapbase - *vaddrbase */
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Elf_Dyn *dynamic; /* Dynamic section */
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caddr_t entry; /* Entry point */
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const Elf_Phdr *phdr; /* Program header (may be xmalloc'ed) */
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size_t phsize; /* Size of program header in bytes */
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/* Items from the dynamic section. */
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Elf_Addr *pltgot; /* PLTGOT table */
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const Elf_Rel *rel; /* Relocation entries */
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const Elf_Rel *rellim; /* Limit of Relocation entries */
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const Elf_Rela *rela; /* Relocation entries */
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const Elf_Rela *relalim; /* Limit of Relocation entries */
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const Elf_Rel *pltrel; /* PLT relocation entries */
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const Elf_Rel *pltrellim; /* Limit of PLT relocation entries */
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const Elf_Rela *pltrela; /* PLT relocation entries */
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const Elf_Rela *pltrelalim; /* Limit of PLT relocation entries */
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const Elf_Sym *symtab; /* Symbol table */
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const char *strtab; /* String table */
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unsigned long strsize; /* Size in bytes of string table */
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#ifdef __mips__
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Elf_Word local_gotno; /* Number of local GOT entries */
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Elf_Word symtabno; /* Number of dynamic symbols */
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Elf_Word gotsym; /* First dynamic symbol in GOT */
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#endif
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const Elf_Symindx *buckets; /* Hash table buckets array */
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unsigned long unused1; /* Used to be nbuckets */
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const Elf_Symindx *chains; /* Hash table chain array */
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unsigned long nchains; /* Number of chains */
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Search_Path *rpaths; /* Search path specified in object */
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Needed_Entry *needed; /* Shared objects needed by this (%) */
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void (*init)(void); /* Initialization function to call */
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void (*fini)(void); /* Termination function to call */
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/* Entry points for dlopen() and friends. */
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void *(*dlopen)(const char *, int);
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void *(*dlsym)(void *, const char *);
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void *(*dlvsym)(void *, const char *, const char *);
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char *(*dlerror)(void);
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int (*dlclose)(void *);
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int (*dladdr)(const void *, Dl_info *);
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u_int32_t mainprog:1, /* True if this is the main program */
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rtld:1, /* True if this is the dynamic linker */
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textrel:1, /* True if there are relocations to
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* text seg */
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symbolic:1, /* True if generated with
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* "-Bsymbolic" */
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printed:1, /* True if ldd has printed it */
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isdynamic:1, /* True if this is a pure PIC object */
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mainref:1, /* True if on _rtld_list_main */
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globalref:1, /* True if on _rtld_list_global */
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init_done:1, /* True if .init has been added */
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init_called:1, /* True if .init function has been
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* called */
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fini_called:1, /* True if .fini function has been
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* called */
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z_now:1, /* True if object's symbols should be
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bound immediately */
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z_nodelete:1, /* True if object should never be
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unloaded */
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z_initfirst:1, /* True if object's .init/.fini take
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* priority over others */
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z_noopen:1, /* True if object should never be
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dlopen'ed */
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phdr_loaded:1, /* Phdr is loaded and doesn't need to
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* be freed. */
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#if defined(__HAVE_TLS_VARIANT_I) || defined(__HAVE_TLS_VARIANT_II)
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tls_done:1, /* True if static TLS offset
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* has been allocated */
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#endif
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ref_nodel:1; /* Refcount increased to prevent dlclose */
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struct link_map linkmap; /* for GDB */
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/* These items are computed by map_object() or by digest_phdr(). */
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const char *interp; /* Pathname of the interpreter, if any */
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Objlist dldags; /* Object belongs to these dlopened DAGs (%) */
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Objlist dagmembers; /* DAG has these members (%) */
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dev_t dev; /* Object's filesystem's device */
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ino_t ino; /* Object's inode number */
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void *ehdr;
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uint32_t nbuckets; /* Number of buckets */
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uint32_t nbuckets_m; /* Precomputed for fast remainder */
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uint8_t nbuckets_s1;
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uint8_t nbuckets_s2;
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size_t pathlen; /* Pathname length */
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STAILQ_HEAD(, Struct_Name_Entry) names; /* List of names for this object we
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know about. */
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#ifdef __powerpc__
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Elf_Addr *gotptr; /* GOT table (secure-plt only) */
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#endif
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#if defined(__HAVE_TLS_VARIANT_I) || defined(__HAVE_TLS_VARIANT_II)
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/* Thread Local Storage support for this module */
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size_t tlsindex; /* Index in DTV */
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void *tlsinit; /* Base address of TLS init block */
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size_t tlsinitsize; /* Size of TLS init block */
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size_t tlssize; /* Size of TLS block */
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size_t tlsoffset; /* Offset in the static TLS block */
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size_t tlsalign; /* Needed alignment for static TLS */
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#endif
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/* symbol versioning */
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const Elf_Verneed *verneed; /* Required versions. */
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Elf_Word verneednum; /* Number of entries in verneed table */
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const Elf_Verdef *verdef; /* Provided versions. */
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Elf_Word verdefnum; /* Number of entries in verdef table */
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const Elf_Versym *versyms; /* Symbol versions table */
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Ver_Entry *vertab; /* Versions required/defined by this
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* object */
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int vertabnum; /* Number of entries in vertab */
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} Obj_Entry;
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typedef struct Struct_DoneList {
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const Obj_Entry **objs; /* Array of object pointers */
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unsigned int num_alloc; /* Allocated size of the array */
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unsigned int num_used; /* Number of array slots used */
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} DoneList;
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#if defined(_RTLD_SOURCE)
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extern struct r_debug _rtld_debug;
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extern Search_Path *_rtld_default_paths;
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extern Obj_Entry *_rtld_objlist;
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extern Obj_Entry **_rtld_objtail;
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extern u_int _rtld_objcount;
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extern u_int _rtld_objloads;
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extern Obj_Entry *_rtld_objmain;
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extern Obj_Entry _rtld_objself;
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extern Search_Path *_rtld_paths;
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extern Library_Xform *_rtld_xforms;
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extern bool _rtld_trust;
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extern Objlist _rtld_list_global;
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extern Objlist _rtld_list_main;
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extern Elf_Sym _rtld_sym_zero;
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#define RTLD_MODEMASK 0x3
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/* Flags to be passed into _rtld_symlook_ family of functions. */
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#define SYMLOOK_IN_PLT 0x01 /* Lookup for PLT symbol */
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#define SYMLOOK_DLSYM 0x02 /* Return newes versioned symbol.
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Used by dlsym. */
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/* Flags for _rtld_load_object() and friends. */
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#define _RTLD_GLOBAL 0x01 /* Add object to global DAG. */
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#define _RTLD_MAIN 0x02
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#define _RTLD_NOLOAD 0x04 /* dlopen() specified RTLD_NOLOAD. */
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#define _RTLD_DLOPEN 0x08 /* Load_object() called from dlopen(). */
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/* Preallocation for static TLS model */
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#define RTLD_STATIC_TLS_RESERVATION 64
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/* rtld.c */
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/* We export these symbols using _rtld_symbol_lookup and is_exported. */
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__dso_public char *dlerror(void);
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__dso_public void *dlopen(const char *, int);
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__dso_public void *dlsym(void *, const char *);
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__dso_public int dlclose(void *);
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__dso_public int dladdr(const void *, Dl_info *);
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__dso_public int dlinfo(void *, int, void *);
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__dso_public int dl_iterate_phdr(int (*)(struct dl_phdr_info *, size_t, void *),
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void *);
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/* These aren't exported */
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void _rtld_error(const char *, ...)
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__attribute__((__format__(__printf__,1,2)));
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void _rtld_die(void) __attribute__((__noreturn__));
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void *_rtld_objmain_sym(const char *);
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__dso_public void _rtld_debug_state(void);
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void _rtld_linkmap_add(Obj_Entry *);
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void _rtld_linkmap_delete(Obj_Entry *);
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void _rtld_objlist_push_head(Objlist *, Obj_Entry *);
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void _rtld_objlist_push_tail(Objlist *, Obj_Entry *);
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Objlist_Entry *_rtld_objlist_find(Objlist *, const Obj_Entry *);
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void _rtld_ref_dag(Obj_Entry *);
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void _rtld_shared_enter(void);
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void _rtld_shared_exit(void);
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void _rtld_exclusive_enter(sigset_t *);
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void _rtld_exclusive_exit(sigset_t *);
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/* expand.c */
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size_t _rtld_expand_path(char *, size_t, const char *, const char *,\
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const char *);
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/* headers.c */
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void _rtld_digest_dynamic(const char *, Obj_Entry *);
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Obj_Entry *_rtld_digest_phdr(const Elf_Phdr *, int, caddr_t);
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/* load.c */
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Obj_Entry *_rtld_load_object(const char *, int);
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int _rtld_load_needed_objects(Obj_Entry *, int);
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int _rtld_preload(const char *);
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#define OBJ_ERR (Obj_Entry *)(-1)
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/* path.c */
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void _rtld_add_paths(const char *, Search_Path **, const char *);
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void _rtld_process_hints(const char *, Search_Path **, Library_Xform **,
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const char *);
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int _rtld_sysctl(const char *, void *, size_t *);
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/* reloc.c */
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int _rtld_do_copy_relocations(const Obj_Entry *);
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int _rtld_relocate_objects(Obj_Entry *, bool);
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int _rtld_relocate_nonplt_objects(Obj_Entry *);
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int _rtld_relocate_plt_lazy(const Obj_Entry *);
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int _rtld_relocate_plt_objects(const Obj_Entry *);
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void _rtld_setup_pltgot(const Obj_Entry *);
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/* search.c */
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Obj_Entry *_rtld_load_library(const char *, const Obj_Entry *, int);
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/* symbol.c */
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unsigned long _rtld_elf_hash(const char *);
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const Elf_Sym *_rtld_symlook_obj(const char *, unsigned long,
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const Obj_Entry *, u_int, const Ver_Entry *);
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const Elf_Sym *_rtld_find_symdef(unsigned long, const Obj_Entry *,
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const Obj_Entry **, u_int);
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const Elf_Sym *_rtld_find_plt_symdef(unsigned long, const Obj_Entry *,
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const Obj_Entry **, bool);
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const Elf_Sym *_rtld_symlook_list(const char *, unsigned long,
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const Objlist *, const Obj_Entry **, u_int, const Ver_Entry *, DoneList *);
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const Elf_Sym *_rtld_symlook_default(const char *, unsigned long,
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const Obj_Entry *, const Obj_Entry **, u_int, const Ver_Entry *);
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const Elf_Sym *_rtld_symlook_needed(const char *, unsigned long,
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const Needed_Entry *, const Obj_Entry **, u_int, const Ver_Entry *,
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DoneList *, DoneList *);
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#ifdef COMBRELOC
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void _rtld_combreloc_reset(const Obj_Entry *);
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#endif
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/* symver.c */
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int _rtld_object_match_name(const Obj_Entry *, const char *);
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int _rtld_verify_object_versions(Obj_Entry *);
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static __inline const Ver_Entry *
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_rtld_fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
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{
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Elf_Half vernum;
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if (obj->vertab) {
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vernum = VER_NDX(obj->versyms[symnum].vs_vers);
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if (vernum >= obj->vertabnum) {
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_rtld_error("%s: symbol %s has wrong verneed value %d",
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obj->path, &obj->strtab[symnum], vernum);
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} else if (obj->vertab[vernum].hash) {
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return &obj->vertab[vernum];
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}
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}
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return NULL;
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}
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#if defined(__HAVE_TLS_VARIANT_I) || defined(__HAVE_TLS_VARIANT_II)
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/* tls.c */
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void *_rtld_tls_get_addr(void *, size_t, size_t);
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void _rtld_tls_initial_allocation(void);
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void *_rtld_tls_module_allocate(size_t index);
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int _rtld_tls_offset_allocate(Obj_Entry *);
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void _rtld_tls_offset_free(Obj_Entry *);
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extern size_t _rtld_tls_dtv_generation;
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extern size_t _rtld_tls_max_index;
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__dso_public extern void *__tls_get_addr(void *);
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#ifdef __i386__
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__dso_public extern void *___tls_get_addr(void *)
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__attribute__((__regparm__(1)));
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#endif
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#endif
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/* map_object.c */
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struct stat;
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Obj_Entry *_rtld_map_object(const char *, int, const struct stat *);
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void _rtld_obj_free(Obj_Entry *);
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Obj_Entry *_rtld_obj_new(void);
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/* function descriptors */
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#ifdef __HAVE_FUNCTION_DESCRIPTORS
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Elf_Addr _rtld_function_descriptor_alloc(const Obj_Entry *,
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const Elf_Sym *, Elf_Addr);
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const void *_rtld_function_descriptor_function(const void *);
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#endif /* __HAVE_FUNCTION_DESCRIPTORS */
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#endif /* _RTLD_SOURCE */
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#endif /* RTLD_H */
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