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/* Run-time dynamic linker data structures for loaded ELF shared objects.
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Copyright (C) 1995-2012 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <fpu_control.h>
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#include <dl-lookupcfg.h>
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#include <dl-sysdep.h>
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#include <bits/libc-lock.h>
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#include <hp-timing.h>
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#include <kernel-features.h>
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/* We use this macro to refer to ELF types independent of the native wordsize.
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`ElfW(TYPE)' is used in place of `Elf32_TYPE' or `Elf64_TYPE'. */
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#define ELFW(type) _ElfW (ELF, __ELF_NATIVE_CLASS, type)
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/* All references to the value of l_info[DT_PLTGOT],
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l_info[DT_STRTAB], l_info[DT_SYMTAB], l_info[DT_RELA],
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l_info[DT_REL], l_info[DT_JMPREL], and l_info[VERSYMIDX (DT_VERSYM)]
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have to be accessed via the D_PTR macro. The macro is needed since for
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most architectures the entry is already relocated - but for some not
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and we need to relocate at access time. */
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#ifdef DL_RO_DYN_SECTION
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# define D_PTR(map, i) ((map)->i->d_un.d_ptr + (map)->l_addr)
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# define D_PTR(map, i) (map)->i->d_un.d_ptr
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/* Result of the lookup functions and how to retrieve the base address. */
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typedef struct link_map *lookup_t;
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#define LOOKUP_VALUE(map) map
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#define LOOKUP_VALUE_ADDRESS(map) ((map) ? (map)->l_addr : 0)
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/* On some architectures a pointer to a function is not just a pointer
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to the actual code of the function but rather an architecture
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specific descriptor. */
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#ifndef ELF_FUNCTION_PTR_IS_SPECIAL
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# define DL_SYMBOL_ADDRESS(map, ref) \
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(void *) (LOOKUP_VALUE_ADDRESS (map) + ref->st_value)
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# define DL_LOOKUP_ADDRESS(addr) ((ElfW(Addr)) (addr))
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# define DL_DT_INIT_ADDRESS(map, start) (start)
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# define DL_DT_FINI_ADDRESS(map, start) (start)
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/* On some architectures dladdr can't use st_size of all symbols this way. */
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#define DL_ADDR_SYM_MATCH(L, SYM, MATCHSYM, ADDR) \
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((ADDR) >= (L)->l_addr + (SYM)->st_value \
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&& ((((SYM)->st_shndx == SHN_UNDEF || (SYM)->st_size == 0) \
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&& (ADDR) == (L)->l_addr + (SYM)->st_value) \
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|| (ADDR) < (L)->l_addr + (SYM)->st_value + (SYM)->st_size) \
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&& ((MATCHSYM) == NULL || (MATCHSYM)->st_value < (SYM)->st_value))
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/* Unmap a loaded object, called by _dl_close (). */
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#ifndef DL_UNMAP_IS_SPECIAL
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# define DL_UNMAP(map) \
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__munmap ((void *) (map)->l_map_start, \
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(map)->l_map_end - (map)->l_map_start)
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/* By default we do not need special support to initialize DSOs loaded
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by statically linked binaries. */
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#ifndef DL_STATIC_INIT
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# define DL_STATIC_INIT(map)
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/* Reloc type classes as returned by elf_machine_type_class().
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ELF_RTYPE_CLASS_PLT means this reloc should not be satisfied by
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some PLT symbol, ELF_RTYPE_CLASS_COPY means this reloc should not be
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satisfied by any symbol in the executable. Some architectures do
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not support copy relocations. In this case we define the macro to
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zero so that the code for handling them gets automatically optimized
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#define ELF_RTYPE_CLASS_PLT 1
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#ifndef DL_NO_COPY_RELOCS
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# define ELF_RTYPE_CLASS_COPY 2
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# define ELF_RTYPE_CLASS_COPY 0
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/* ELF uses the PF_x macros to specify the segment permissions, mmap
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uses PROT_xxx. In most cases the three macros have the values 1, 2,
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and 3 but not in a matching order. The following macros allows
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converting from the PF_x values to PROT_xxx values. */
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((PROT_READ << (PF_R * 4)) \
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| (PROT_WRITE << (PF_W * 4)) \
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| (PROT_EXEC << (PF_X * 4)) \
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| ((PROT_READ | PROT_WRITE) << ((PF_R | PF_W) * 4)) \
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| ((PROT_READ | PROT_EXEC) << ((PF_R | PF_X) * 4)) \
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| ((PROT_WRITE | PROT_EXEC) << (PF_W | PF_X) * 4) \
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| ((PROT_READ | PROT_WRITE | PROT_EXEC) << ((PF_R | PF_W | PF_X) * 4)))
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/* For the version handling we need an array with only names and their
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struct r_found_version
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const char *filename;
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/* We want to cache information about the searches for shared objects. */
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enum r_dir_status { unknown, nonexisting, existing };
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struct r_search_path_elem
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/* This link is only used in the `all_dirs' member of `r_search_path'. */
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struct r_search_path_elem *next;
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/* Strings saying where the definition came from. */
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/* Basename for this search path element. The string must end with
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a slash character. */
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enum r_dir_status status[0];
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/* A data structure for a simple single linked list of strings. */
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const char *name; /* Name requested (before search). */
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struct libname_list *next; /* Link to next name for this object. */
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int dont_free; /* Flag whether this element should be freed
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if the object is not entirely unloaded. */
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/* Bit masks for the objects which valid callers can come from to
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functions with restricted interface. */
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allow_libpthread = 4,
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/* Type for list of auditing interfaces. */
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struct La_i86_retval;
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struct La_x86_64_regs;
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struct La_x86_64_retval;
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struct La_x32_retval;
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struct La_ppc32_regs;
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struct La_ppc32_retval;
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struct La_ppc64_regs;
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struct La_ppc64_retval;
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struct La_s390_32_regs;
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struct La_s390_32_retval;
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struct La_s390_64_regs;
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struct La_s390_64_retval;
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struct La_sparc32_regs;
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struct La_sparc32_retval;
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struct La_sparc64_regs;
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struct La_sparc64_retval;
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void (*activity) (uintptr_t *, unsigned int);
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char *(*objsearch) (const char *, uintptr_t *, unsigned int);
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unsigned int (*objopen) (struct link_map *, Lmid_t, uintptr_t *);
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void (*preinit) (uintptr_t *);
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uintptr_t (*symbind32) (Elf32_Sym *, unsigned int, uintptr_t *,
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uintptr_t *, unsigned int *, const char *);
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uintptr_t (*symbind64) (Elf64_Sym *, unsigned int, uintptr_t *,
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uintptr_t *, unsigned int *, const char *);
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Elf32_Addr (*i86_gnu_pltenter) (Elf32_Sym *, unsigned int, uintptr_t *,
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uintptr_t *, struct La_i86_regs *,
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unsigned int *, const char *name,
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long int *framesizep);
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Elf64_Addr (*x86_64_gnu_pltenter) (Elf64_Sym *, unsigned int, uintptr_t *,
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uintptr_t *, struct La_x86_64_regs *,
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unsigned int *, const char *name,
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long int *framesizep);
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Elf32_Addr (*x32_gnu_pltenter) (Elf32_Sym *, unsigned int, uintptr_t *,
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uintptr_t *, struct La_x32_regs *,
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unsigned int *, const char *name,
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long int *framesizep);
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Elf32_Addr (*ppc32_gnu_pltenter) (Elf32_Sym *, unsigned int, uintptr_t *,
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uintptr_t *, struct La_ppc32_regs *,
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unsigned int *, const char *name,
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long int *framesizep);
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Elf64_Addr (*ppc64_gnu_pltenter) (Elf64_Sym *, unsigned int, uintptr_t *,
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uintptr_t *, struct La_ppc64_regs *,
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unsigned int *, const char *name,
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long int *framesizep);
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uintptr_t (*sh_gnu_pltenter) (Elf32_Sym *, unsigned int, uintptr_t *,
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uintptr_t *, const struct La_sh_regs *,
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unsigned int *, const char *name,
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long int *framesizep);
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Elf32_Addr (*s390_32_gnu_pltenter) (Elf32_Sym *, unsigned int, uintptr_t *,
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uintptr_t *, struct La_s390_32_regs *,
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unsigned int *, const char *name,
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long int *framesizep);
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Elf64_Addr (*s390_64_gnu_pltenter) (Elf64_Sym *, unsigned int, uintptr_t *,
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uintptr_t *, struct La_s390_64_regs *,
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unsigned int *, const char *name,
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long int *framesizep);
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Elf32_Addr (*sparc32_gnu_pltenter) (Elf32_Sym *, unsigned int,
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uintptr_t *, uintptr_t *,
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const struct La_sparc32_regs *,
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unsigned int *, const char *name,
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long int *framesizep);
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Elf64_Addr (*sparc64_gnu_pltenter) (Elf64_Sym *, unsigned int,
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uintptr_t *, uintptr_t *,
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const struct La_sparc64_regs *,
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unsigned int *, const char *name,
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long int *framesizep);
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#ifdef ARCH_PLTENTER_MEMBERS
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ARCH_PLTENTER_MEMBERS;
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unsigned int (*i86_gnu_pltexit) (Elf32_Sym *, unsigned int, uintptr_t *,
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uintptr_t *, const struct La_i86_regs *,
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struct La_i86_retval *, const char *);
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unsigned int (*x86_64_gnu_pltexit) (Elf64_Sym *, unsigned int, uintptr_t *,
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const struct La_x86_64_regs *,
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struct La_x86_64_retval *,
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unsigned int (*x32_gnu_pltexit) (Elf32_Sym *, unsigned int, uintptr_t *,
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const struct La_x32_regs *,
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struct La_x86_64_retval *,
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unsigned int (*ppc32_gnu_pltexit) (Elf32_Sym *, unsigned int, uintptr_t *,
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const struct La_ppc32_regs *,
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struct La_ppc32_retval *, const char *);
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unsigned int (*ppc64_gnu_pltexit) (Elf64_Sym *, unsigned int, uintptr_t *,
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const struct La_ppc64_regs *,
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struct La_ppc64_retval *, const char *);
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unsigned int (*sh_gnu_pltexit) (Elf32_Sym *, unsigned int, uintptr_t *,
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uintptr_t *, const struct La_sh_regs *,
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struct La_sh_retval *, const char *);
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unsigned int (*s390_32_gnu_pltexit) (Elf32_Sym *, unsigned int,
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uintptr_t *, uintptr_t *,
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const struct La_s390_32_regs *,
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struct La_s390_32_retval *,
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unsigned int (*s390_64_gnu_pltexit) (Elf64_Sym *, unsigned int,
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uintptr_t *, uintptr_t *,
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const struct La_s390_64_regs *,
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struct La_s390_64_retval *,
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unsigned int (*sparc32_gnu_pltexit) (Elf32_Sym *, unsigned int,
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uintptr_t *, uintptr_t *,
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const struct La_sparc32_regs *,
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struct La_sparc32_retval *,
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unsigned int (*sparc64_gnu_pltexit) (Elf64_Sym *, unsigned int,
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uintptr_t *, uintptr_t *,
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const struct La_sparc32_regs *,
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struct La_sparc32_retval *,
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#ifdef ARCH_PLTEXIT_MEMBERS
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ARCH_PLTEXIT_MEMBERS;
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unsigned int (*objclose) (uintptr_t *);
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struct audit_ifaces *next;
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/* Test whether given NAME matches any of the names of the given object. */
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extern int _dl_name_match_p (const char *__name, const struct link_map *__map)
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/* Compute next higher prime number. */
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extern unsigned long int _dl_higher_prime_number (unsigned long int n)
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/* Function used as argument for `_dl_receive_error' function. The
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arguments are the error code, error string, and the objname the
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error occurred in. */
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typedef void (*receiver_fct) (int, const char *, const char *);
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/* Internal functions of the run-time dynamic linker.
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These can be accessed if you link again the dynamic linker
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as a shared library, as in `-lld' or `/lib/ld.so' explicitly;
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but are not normally of interest to user programs.
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The `-ldl' library functions in <dlfcn.h> provide a simple
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user interface to run-time dynamic linking. */
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# define EXTERN extern
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# define GL(name) _##name
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# define GL(name) _rtld_local._##name
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# define GL(name) _rtld_global._##name
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/* Don't change the order of the following elements. 'dl_loaded'
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must remain the first element. Forever. */
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/* Non-shared code has no support for multiple namespaces. */
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EXTERN struct link_namespaces
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/* A pointer to the map for the main map. */
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struct link_map *_ns_loaded;
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/* Number of object in the _dl_loaded list. */
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unsigned int _ns_nloaded;
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/* Direct pointer to the searchlist of the main object. */
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struct r_scope_elem *_ns_main_searchlist;
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/* This is zero at program start to signal that the global scope map is
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allocated by rtld. Later it keeps the size of the map. It might be
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reset if in _dl_close if the last global object is removed. */
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size_t _ns_global_scope_alloc;
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/* Search table for unique objects. */
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struct unique_sym_table
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__rtld_lock_recursive_t lock;
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const ElfW(Sym) *sym;
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const struct link_map *map;
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void (*free) (void *);
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} _ns_unique_sym_table;
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/* Keep track of changes to each namespace' list. */
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struct r_debug _ns_debug;
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/* One higher than index of last used namespace. */
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EXTERN size_t _dl_nns;
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/* During the program run we must not modify the global data of
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loaded shared object simultanously in two threads. Therefore we
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protect `_dl_open' and `_dl_close' in dl-close.c.
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This must be a recursive lock since the initializer function of
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the loaded object might as well require a call to this function.
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At this time it is not anymore a problem to modify the tables. */
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__rtld_lock_define_recursive (EXTERN, _dl_load_lock)
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/* This lock is used to keep __dl_iterate_phdr from inspecting the
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list of loaded objects while an object is added to or removed
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__rtld_lock_define_recursive (EXTERN, _dl_load_write_lock)
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/* Incremented whenever something may have been added to dl_loaded. */
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EXTERN unsigned long long _dl_load_adds;
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/* The object to be initialized first. */
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EXTERN struct link_map *_dl_initfirst;
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#if HP_TIMING_AVAIL || HP_SMALL_TIMING_AVAIL
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/* Start time on CPU clock. */
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EXTERN hp_timing_t _dl_cpuclock_offset;
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/* Map of shared object to be profiled. */
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EXTERN struct link_map *_dl_profile_map;
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/* Counters for the number of relocations performed. */
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EXTERN unsigned long int _dl_num_relocations;
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EXTERN unsigned long int _dl_num_cache_relocations;
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/* List of search directories. */
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EXTERN struct r_search_path_elem *_dl_all_dirs;
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#ifdef _LIBC_REENTRANT
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EXTERN void **(*_dl_error_catch_tsd) (void) __attribute__ ((const));
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/* Structure describing the dynamic linker itself. We need to
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reserve memory for the data the audit libraries need. */
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EXTERN struct link_map _dl_rtld_map;
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struct auditstate audit_data[DL_NNS];
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#if defined SHARED && defined _LIBC_REENTRANT \
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&& defined __rtld_lock_default_lock_recursive
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EXTERN void (*_dl_rtld_lock_recursive) (void *);
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EXTERN void (*_dl_rtld_unlock_recursive) (void *);
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/* If loading a shared object requires that we make the stack executable
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when it was not, we do it by calling this function.
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It returns an errno code or zero on success. */
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EXTERN int (*_dl_make_stack_executable_hook) (void **) internal_function;
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/* Prevailing state of the stack, PF_X indicating it's executable. */
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EXTERN ElfW(Word) _dl_stack_flags;
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/* Flag signalling whether there are gaps in the module ID allocation. */
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EXTERN bool _dl_tls_dtv_gaps;
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/* Highest dtv index currently needed. */
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EXTERN size_t _dl_tls_max_dtv_idx;
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/* Information about the dtv slots. */
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EXTERN struct dtv_slotinfo_list
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struct dtv_slotinfo_list *next;
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struct link_map *map;
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} *_dl_tls_dtv_slotinfo_list;
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/* Number of modules in the static TLS block. */
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EXTERN size_t _dl_tls_static_nelem;
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/* Size of the static TLS block. */
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EXTERN size_t _dl_tls_static_size;
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/* Size actually allocated in the static TLS block. */
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EXTERN size_t _dl_tls_static_used;
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/* Alignment requirement of the static TLS block. */
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EXTERN size_t _dl_tls_static_align;
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/* Number of additional entries in the slotinfo array of each slotinfo
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list element. A large number makes it almost certain take we never
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have to iterate beyond the first element in the slotinfo list. */
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#define TLS_SLOTINFO_SURPLUS (62)
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/* Number of additional slots in the dtv allocated. */
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#define DTV_SURPLUS (14)
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/* Initial dtv of the main thread, not allocated with normal malloc. */
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EXTERN void *_dl_initial_dtv;
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/* Generation counter for the dtv. */
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EXTERN size_t _dl_tls_generation;
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EXTERN void (*_dl_init_static_tls) (struct link_map *);
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EXTERN void (*_dl_wait_lookup_done) (void);
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/* Scopes to free after next THREAD_GSCOPE_WAIT (). */
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EXTERN struct dl_scope_free_list
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} *_dl_scope_free_list;
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# define __rtld_global_attribute__
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# ifdef HAVE_SDATA_SECTION
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# define __rtld_local_attribute__ \
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__attribute__ ((visibility ("hidden"), section (".sdata")))
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# undef __rtld_global_attribute__
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# define __rtld_global_attribute__ __attribute__ ((section (".sdata")))
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# define __rtld_local_attribute__ __attribute__ ((visibility ("hidden")))
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extern struct rtld_global _rtld_local __rtld_local_attribute__;
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# undef __rtld_local_attribute__
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extern struct rtld_global _rtld_global __rtld_global_attribute__;
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# undef __rtld_global_attribute__
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#if __OPTION_EGLIBC_RTLD_DEBUG
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# define GLRO_dl_debug_mask GLRO(dl_debug_mask)
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# define GLRO_dl_debug_mask 0
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# define GLRO(name) _##name
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# define GLRO(name) _rtld_local_ro._##name
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# define GLRO(name) _rtld_global_ro._##name
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struct rtld_global_ro
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#if __OPTION_EGLIBC_RTLD_DEBUG
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/* If nonzero the appropriate debug information is printed. */
546
EXTERN int _dl_debug_mask;
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#define DL_DEBUG_LIBS (1 << 0)
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#define DL_DEBUG_IMPCALLS (1 << 1)
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#define DL_DEBUG_BINDINGS (1 << 2)
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#define DL_DEBUG_SYMBOLS (1 << 3)
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#define DL_DEBUG_VERSIONS (1 << 4)
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#define DL_DEBUG_RELOC (1 << 5)
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#define DL_DEBUG_FILES (1 << 6)
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#define DL_DEBUG_STATISTICS (1 << 7)
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#define DL_DEBUG_UNUSED (1 << 8)
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#define DL_DEBUG_SCOPES (1 << 9)
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/* These two are used only internally. */
559
#define DL_DEBUG_HELP (1 << 10)
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#define DL_DEBUG_PRELINK (1 << 11)
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EXTERN unsigned int _dl_osversion;
565
EXTERN const char *_dl_platform;
566
EXTERN size_t _dl_platformlen;
568
/* Cached value of `getpagesize ()'. */
569
EXTERN size_t _dl_pagesize;
571
/* Do we read from ld.so.cache? */
572
EXTERN int _dl_inhibit_cache;
574
/* Copy of the content of `_dl_main_searchlist' at startup time. */
575
EXTERN struct r_scope_elem _dl_initial_searchlist;
577
/* CLK_TCK as reported by the kernel. */
578
EXTERN int _dl_clktck;
580
/* If nonzero print warnings messages. */
581
EXTERN int _dl_verbose;
583
/* File descriptor to write debug messages to. */
584
EXTERN int _dl_debug_fd;
586
/* Do we do lazy relocations? */
589
/* Nonzero if runtime lookups should not update the .got/.plt. */
590
EXTERN int _dl_bind_not;
592
/* Nonzero if references should be treated as weak during runtime
594
EXTERN int _dl_dynamic_weak;
596
/* Default floating-point control word. */
597
EXTERN fpu_control_t _dl_fpu_control;
599
/* Expected cache ID. */
600
EXTERN int _dl_correct_cache_id;
602
/* Mask for hardware capabilities that are available. */
603
EXTERN uint64_t _dl_hwcap;
605
/* Mask for important hardware capabilities we honour. */
606
EXTERN uint64_t _dl_hwcap_mask;
608
/* Pointer to the auxv list supplied to the program at startup. */
609
EXTERN ElfW(auxv_t) *_dl_auxv;
611
/* Get architecture specific definitions. */
612
#define PROCINFO_DECL
613
#ifndef PROCINFO_CLASS
614
# define PROCINFO_CLASS EXTERN
616
#include <dl-procinfo.c>
618
/* Names of shared object for which the RPATH should be ignored. */
619
EXTERN const char *_dl_inhibit_rpath;
621
/* Location of the binary. */
622
EXTERN const char *_dl_origin_path;
624
/* -1 if the dynamic linker should honor library load bias,
625
0 if not, -2 use the default (honor biases for normal
626
binaries, don't honor for PIEs). */
627
EXTERN ElfW(Addr) _dl_use_load_bias;
629
/* Name of the shared object to be profiled (if any). */
630
EXTERN const char *_dl_profile;
631
/* Filename of the output file. */
632
EXTERN const char *_dl_profile_output;
633
/* Name of the object we want to trace the prelinking. */
634
EXTERN const char *_dl_trace_prelink;
635
/* Map of shared object to be prelink traced. */
636
EXTERN struct link_map *_dl_trace_prelink_map;
638
/* All search directories defined at startup. */
639
EXTERN struct r_search_path_elem *_dl_init_all_dirs;
641
#if HP_TIMING_AVAIL || HP_SMALL_TIMING_AVAIL
642
/* Overhead of a high-precision timing measurement. */
643
EXTERN hp_timing_t _dl_hp_timing_overhead;
646
#ifdef NEED_DL_SYSINFO
647
/* Syscall handling improvements. This is very specific to x86. */
648
EXTERN uintptr_t _dl_sysinfo;
651
#if defined NEED_DL_SYSINFO || defined NEED_DL_SYSINFO_DSO
652
/* The vsyscall page is a virtual DSO pre-mapped by the kernel.
653
This points to its ELF header. */
654
EXTERN const ElfW(Ehdr) *_dl_sysinfo_dso;
656
/* At startup time we set up the normal DSO data structure for it,
657
and this points to it. */
658
EXTERN struct link_map *_dl_sysinfo_map;
662
/* We add a function table to _rtld_global which is then used to
663
call the function instead of going through the PLT. The result
664
is that we can avoid exporting the functions and we do not jump
665
PLT relocations in libc.so. */
666
void (*_dl_debug_printf) (const char *, ...)
667
__attribute__ ((__format__ (__printf__, 1, 2)));
668
int (internal_function *_dl_catch_error) (const char **, const char **,
669
bool *, void (*) (void *), void *);
670
void (internal_function *_dl_signal_error) (int, const char *, const char *,
672
void (*_dl_mcount) (ElfW(Addr) frompc, ElfW(Addr) selfpc);
673
lookup_t (internal_function *_dl_lookup_symbol_x) (const char *,
676
struct r_scope_elem *[],
677
const struct r_found_version *,
680
int (*_dl_check_caller) (const void *, enum allowmask);
681
void *(*_dl_open) (const char *file, int mode, const void *caller_dlopen,
682
Lmid_t nsid, int argc, char *argv[], char *env[]);
683
void (*_dl_close) (void *map);
684
void *(*_dl_tls_get_addr_soft) (struct link_map *);
685
#ifdef HAVE_DL_DISCOVER_OSVERSION
686
int (*_dl_discover_osversion) (void);
689
/* List of auditing interfaces. */
690
struct audit_ifaces *_dl_audit;
691
unsigned int _dl_naudit;
693
/* 0 if internal pointer values should not be guarded, 1 if they should. */
694
EXTERN int _dl_pointer_guard;
696
# define __rtld_global_attribute__
698
# define __rtld_local_attribute__ __attribute__ ((visibility ("hidden")))
699
extern struct rtld_global_ro _rtld_local_ro
700
attribute_relro __rtld_local_attribute__;
701
extern struct rtld_global_ro _rtld_global_ro
702
attribute_relro __rtld_global_attribute__;
703
# undef __rtld_local_attribute__
705
/* We cheat a bit here. We declare the variable as as const even
706
though it is at startup. */
707
extern const struct rtld_global_ro _rtld_global_ro
708
attribute_relro __rtld_global_attribute__;
710
# undef __rtld_global_attribute__
715
/* This is the initial value of GL(dl_error_catch_tsd).
716
A non-TLS libpthread will change it. */
717
extern void **_dl_initial_error_catch_tsd (void) __attribute__ ((const))
721
/* This is the initial value of GL(dl_make_stack_executable_hook).
722
A threads library can change it. */
723
extern int _dl_make_stack_executable (void **stack_endp) internal_function;
724
rtld_hidden_proto (_dl_make_stack_executable)
726
/* Variable pointing to the end of the stack (or close to it). This value
727
must be constant over the runtime of the application. Some programs
728
might use the variable which results in copy relocations on some
729
platforms. But this does not matter, ld.so can always use the local
731
extern void *__libc_stack_end
732
#ifndef LIBC_STACK_END_NOT_RELRO
736
rtld_hidden_proto (__libc_stack_end)
738
/* Parameters passed to the dynamic linker. */
739
extern int _dl_argc attribute_hidden attribute_relro;
740
extern char **_dl_argv
741
#ifndef DL_ARGV_NOT_RELRO
746
extern char **_dl_argv_internal attribute_hidden
747
# ifndef DL_ARGV_NOT_RELRO
751
# define rtld_progname (INTUSE(_dl_argv)[0])
753
# define rtld_progname _dl_argv[0]
756
/* Flag set at startup and cleared when the last initializer has run. */
757
extern int _dl_starting_up;
758
weak_extern (_dl_starting_up)
760
extern int _dl_starting_up_internal attribute_hidden;
763
/* Random data provided by the kernel. */
764
extern void *_dl_random attribute_hidden attribute_relro;
766
/* OS-dependent function to open the zero-fill device. */
767
extern int _dl_sysdep_open_zero_fill (void); /* dl-sysdep.c */
770
/* Write message on the debug file descriptor. The parameters are
771
interpreted as for a `printf' call. All the lines start with a
772
tag showing the PID. */
773
extern void _dl_debug_printf (const char *fmt, ...)
774
__attribute__ ((__format__ (__printf__, 1, 2))) attribute_hidden;
776
/* Write message on the debug file descriptor. The parameters are
777
interpreted as for a `printf' call. All the lines buf the first
778
start with a tag showing the PID. */
779
extern void _dl_debug_printf_c (const char *fmt, ...)
780
__attribute__ ((__format__ (__printf__, 1, 2)));
783
/* Write a message on the specified descriptor FD. The parameters are
784
interpreted as for a `printf' call. */
785
extern void _dl_dprintf (int fd, const char *fmt, ...)
786
__attribute__ ((__format__ (__printf__, 2, 3)))
789
/* Write a message on the specified descriptor standard output. The
790
parameters are interpreted as for a `printf' call. */
791
#define _dl_printf(fmt, args...) \
792
_dl_dprintf (STDOUT_FILENO, fmt, ##args)
794
/* Write a message on the specified descriptor standard error. The
795
parameters are interpreted as for a `printf' call. */
796
#define _dl_error_printf(fmt, args...) \
797
_dl_dprintf (STDERR_FILENO, fmt, ##args)
799
/* Write a message on the specified descriptor standard error and exit
800
the program. The parameters are interpreted as for a `printf' call. */
801
#define _dl_fatal_printf(fmt, args...) \
804
_dl_dprintf (STDERR_FILENO, fmt, ##args); \
810
/* This function is called by all the internal dynamic linker functions
811
when they encounter an error. ERRCODE is either an `errno' code or
812
zero; OBJECT is the name of the problematical shared object, or null if
813
it is a general problem; ERRSTRING is a string describing the specific
815
extern void _dl_signal_error (int errcode, const char *object,
816
const char *occurred, const char *errstring)
817
internal_function __attribute__ ((__noreturn__)) attribute_hidden;
819
/* Like _dl_signal_error, but may return when called in the context of
820
_dl_receive_error. */
821
extern void _dl_signal_cerror (int errcode, const char *object,
822
const char *occation, const char *errstring)
825
/* Call OPERATE, receiving errors from `dl_signal_cerror'. Unlike
826
`_dl_catch_error' the operation is resumed after the OPERATE
828
ARGS is passed as argument to OPERATE. */
829
extern void _dl_receive_error (receiver_fct fct, void (*operate) (void *),
834
/* Open the shared object NAME and map in its segments.
835
LOADER's DT_RPATH is used in searching for NAME.
836
If the object is already opened, returns its existing map. */
837
extern struct link_map *_dl_map_object (struct link_map *loader,
839
int type, int trace_mode, int mode,
841
internal_function attribute_hidden;
843
/* Call _dl_map_object on the dependencies of MAP, and set up
844
MAP->l_searchlist. PRELOADS points to a vector of NPRELOADS previously
845
loaded objects that will be inserted into MAP->l_searchlist after MAP
846
but before its dependencies. */
847
extern void _dl_map_object_deps (struct link_map *map,
848
struct link_map **preloads,
849
unsigned int npreloads, int trace_mode,
851
internal_function attribute_hidden;
853
/* Cache the locations of MAP's hash table. */
854
extern void _dl_setup_hash (struct link_map *map)
855
internal_function attribute_hidden;
858
/* Collect the directories in the search path for LOADER's dependencies.
859
The data structure is defined in <dlfcn.h>. If COUNTING is true,
860
SI->dls_cnt and SI->dls_size are set; if false, those must be as set
861
by a previous call with COUNTING set, and SI must point to SI->dls_size
862
bytes to be used in filling in the result. */
863
extern void _dl_rtld_di_serinfo (struct link_map *loader,
864
Dl_serinfo *si, bool counting)
868
/* Search loaded objects' symbol tables for a definition of the symbol
869
referred to by UNDEF. *SYM is the symbol table entry containing the
870
reference; it is replaced with the defining symbol, and the base load
871
address of the defining object is returned. SYMBOL_SCOPE is a
872
null-terminated list of object scopes to search; each object's
873
l_searchlist (i.e. the segment of the dependency tree starting at that
874
object) is searched in turn. REFERENCE_NAME should name the object
875
containing the reference; it is used in error messages.
876
TYPE_CLASS describes the type of symbol we are looking for. */
879
/* If necessary add dependency between user and provider object. */
880
DL_LOOKUP_ADD_DEPENDENCY = 1,
881
/* Return most recent version instead of default version for
882
unversioned lookup. */
883
DL_LOOKUP_RETURN_NEWEST = 2,
884
/* Set if dl_lookup* called with GSCOPE lock held. */
885
DL_LOOKUP_GSCOPE_LOCK = 4,
888
/* Lookup versioned symbol. */
889
extern lookup_t _dl_lookup_symbol_x (const char *undef,
890
struct link_map *undef_map,
891
const ElfW(Sym) **sym,
892
struct r_scope_elem *symbol_scope[],
893
const struct r_found_version *version,
894
int type_class, int flags,
895
struct link_map *skip_map)
896
internal_function attribute_hidden;
899
/* Look up symbol NAME in MAP's scope and return its run-time address. */
900
extern ElfW(Addr) _dl_symbol_value (struct link_map *map, const char *name)
903
/* Add the new link_map NEW to the end of the namespace list. */
904
extern void _dl_add_to_namespace_list (struct link_map *new, Lmid_t nsid)
905
internal_function attribute_hidden;
907
/* Allocate a `struct link_map' for a new object being loaded. */
908
extern struct link_map *_dl_new_object (char *realname, const char *libname,
909
int type, struct link_map *loader,
910
int mode, Lmid_t nsid)
911
internal_function attribute_hidden;
913
/* Relocate the given object (if it hasn't already been).
914
SCOPE is passed to _dl_lookup_symbol in symbol lookups.
915
If RTLD_LAZY is set in RELOC-MODE, don't relocate its PLT. */
916
extern void _dl_relocate_object (struct link_map *map,
917
struct r_scope_elem *scope[],
918
int reloc_mode, int consider_profiling)
921
/* Protect PT_GNU_RELRO area. */
922
extern void _dl_protect_relro (struct link_map *map)
923
internal_function attribute_hidden;
925
/* Call _dl_signal_error with a message about an unhandled reloc type.
926
TYPE is the result of ELFW(R_TYPE) (r_info), i.e. an R_<CPU>_* value.
927
PLT is nonzero if this was a PLT reloc; it just affects the message. */
928
extern void _dl_reloc_bad_type (struct link_map *map,
929
unsigned int type, int plt)
930
internal_function __attribute__ ((__noreturn__));
932
/* Resolve conflicts if prelinking. */
933
extern void _dl_resolve_conflicts (struct link_map *l,
934
ElfW(Rela) *conflict,
935
ElfW(Rela) *conflictend);
937
/* Check the version dependencies of all objects available through
938
MAP. If VERBOSE print some more diagnostics. */
939
extern int _dl_check_all_versions (struct link_map *map, int verbose,
943
/* Check the version dependencies for MAP. If VERBOSE print some more
945
extern int _dl_check_map_versions (struct link_map *map, int verbose,
949
/* Initialize the object in SCOPE by calling the constructors with
950
ARGC, ARGV, and ENV as the parameters. */
951
extern void _dl_init (struct link_map *main_map, int argc, char **argv,
952
char **env) internal_function attribute_hidden;
954
/* Call the finalizer functions of all shared objects whose
955
initializer functions have completed. */
956
extern void _dl_fini (void) internal_function;
958
/* Sort array MAPS according to dependencies of the contained objects. */
959
extern void _dl_sort_fini (struct link_map **maps, size_t nmaps, char *used,
963
/* The dynamic linker calls this function before and having changing
964
any shared object mappings. The `r_state' member of `struct r_debug'
965
says what change is taking place. This function's address is
966
the value of the `r_brk' member. */
967
extern void _dl_debug_state (void);
968
rtld_hidden_proto (_dl_debug_state)
970
/* Initialize `struct r_debug' if it has not already been done. The
971
argument is the run-time load address of the dynamic linker, to be put
972
in the `r_ldbase' member. Returns the address of the structure. */
973
extern struct r_debug *_dl_debug_initialize (ElfW(Addr) ldbase, Lmid_t ns)
976
/* Initialize the basic data structure for the search paths. */
977
extern void _dl_init_paths (const char *library_path) internal_function;
979
/* Gather the information needed to install the profiling tables and start
981
extern void _dl_start_profile (void) internal_function attribute_hidden;
983
/* The actual functions used to keep book on the calls. */
984
extern void _dl_mcount (ElfW(Addr) frompc, ElfW(Addr) selfpc);
985
extern void _dl_mcount_internal (ElfW(Addr) frompc, ElfW(Addr) selfpc)
988
/* This function is simply a wrapper around the _dl_mcount function
989
which does not require a FROMPC parameter since this is the
991
extern void _dl_mcount_wrapper (void *selfpc);
993
/* Show the members of the auxiliary array passed up from the kernel. */
994
extern void _dl_show_auxv (void) internal_function;
996
/* Return all environment variables starting with `LD_', one after the
998
extern char *_dl_next_ld_env_entry (char ***position) internal_function;
1000
/* Return an array with the names of the important hardware capabilities. */
1001
extern const struct r_strlenpair *_dl_important_hwcaps (const char *platform,
1002
size_t paltform_len,
1004
size_t *max_capstrlen)
1007
/* Look up NAME in ld.so.cache and return the file name stored there,
1008
or null if none is found. */
1009
extern const char *_dl_load_cache_lookup (const char *name)
1012
/* If the system does not support MAP_COPY we cannot leave the file open
1013
all the time since this would create problems when the file is replaced.
1014
Therefore we provide this function to close the file and open it again
1016
extern void _dl_unload_cache (void) attribute_hidden;
1018
/* System-dependent function to read a file's whole contents in the
1019
most convenient manner available. *SIZEP gets the size of the
1020
file. On error MAP_FAILED is returned. */
1021
extern void *_dl_sysdep_read_whole_file (const char *file, size_t *sizep,
1023
internal_function attribute_hidden;
1025
/* System-specific function to do initial startup for the dynamic linker.
1026
After this, file access calls and getenv must work. This is responsible
1027
for setting __libc_enable_secure if we need to be secure (e.g. setuid),
1028
and for setting _dl_argc and _dl_argv, and then calling _dl_main. */
1029
extern ElfW(Addr) _dl_sysdep_start (void **start_argptr,
1030
void (*dl_main) (const ElfW(Phdr) *phdr,
1032
ElfW(Addr) *user_entry,
1033
ElfW(auxv_t) *auxv))
1036
extern void _dl_sysdep_start_cleanup (void)
1037
internal_function attribute_hidden;
1040
/* Determine next available module ID. */
1041
extern size_t _dl_next_tls_modid (void) internal_function attribute_hidden;
1043
/* Calculate offset of the TLS blocks in the static TLS block. */
1044
extern void _dl_determine_tlsoffset (void) internal_function attribute_hidden;
1046
/* Set up the data structures for TLS, when they were not set up at startup.
1047
Returns nonzero on malloc failure.
1048
This is called from _dl_map_object_from_fd or by libpthread. */
1049
extern int _dl_tls_setup (void) internal_function;
1050
rtld_hidden_proto (_dl_tls_setup)
1052
/* Allocate memory for static TLS block (unless MEM is nonzero) and dtv. */
1053
extern void *_dl_allocate_tls (void *mem) internal_function;
1054
rtld_hidden_proto (_dl_allocate_tls)
1056
/* Get size and alignment requirements of the static TLS block. */
1057
extern void _dl_get_tls_static_info (size_t *sizep, size_t *alignp)
1060
extern void _dl_allocate_static_tls (struct link_map *map)
1061
internal_function attribute_hidden;
1063
/* These are internal entry points to the two halves of _dl_allocate_tls,
1064
only used within rtld.c itself at startup time. */
1065
extern void *_dl_allocate_tls_storage (void)
1066
internal_function attribute_hidden;
1067
extern void *_dl_allocate_tls_init (void *) internal_function;
1068
rtld_hidden_proto (_dl_allocate_tls_init)
1070
/* Deallocate memory allocated with _dl_allocate_tls. */
1071
extern void _dl_deallocate_tls (void *tcb, bool dealloc_tcb) internal_function;
1072
rtld_hidden_proto (_dl_deallocate_tls)
1074
extern void _dl_nothread_init_static_tls (struct link_map *) attribute_hidden;
1076
/* Find origin of the executable. */
1077
extern const char *_dl_get_origin (void) attribute_hidden;
1080
extern size_t _dl_dst_count (const char *name, int is_path) attribute_hidden;
1082
/* Substitute DST values. */
1083
extern char *_dl_dst_substitute (struct link_map *l, const char *name,
1084
char *result, int is_path) attribute_hidden;
1086
/* Check validity of the caller. */
1087
extern int _dl_check_caller (const void *caller, enum allowmask mask)
1090
/* Open the shared object NAME, relocate it, and run its initializer if it
1091
hasn't already been run. MODE is as for `dlopen' (see <dlfcn.h>). If
1092
the object is already opened, returns its existing map. */
1093
extern void *_dl_open (const char *name, int mode, const void *caller,
1094
Lmid_t nsid, int argc, char *argv[], char *env[])
1097
/* Free or queue for freeing scope OLD. If other threads might be
1098
in the middle of _dl_fixup, _dl_profile_fixup or dl*sym using the
1099
old scope, OLD can't be freed until no thread is using it. */
1100
extern int _dl_scope_free (void *) attribute_hidden;
1102
/* Add module to slot information data. */
1103
extern void _dl_add_to_slotinfo (struct link_map *l) attribute_hidden;
1105
/* Update slot information data for at least the generation of the
1106
module with the given index. */
1107
extern struct link_map *_dl_update_slotinfo (unsigned long int req_modid);
1109
/* Look up the module's TLS block as for __tls_get_addr,
1110
but never touch anything. Return null if it's not allocated yet. */
1111
extern void *_dl_tls_get_addr_soft (struct link_map *l) attribute_hidden;
1113
extern int _dl_addr_inside_object (struct link_map *l, const ElfW(Addr) addr)
1114
internal_function attribute_hidden;
1116
/* Show show of an object. */
1117
extern void _dl_show_scope (struct link_map *new, int from);
1121
#endif /* ldsodefs.h */