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glibc  2.9
dl-sysdep.h
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00001 /* System-specific settings for dynamic linker code.  IA-32 version.
00002    Copyright (C) 2002, 2003, 2008 Free Software Foundation, Inc.
00003    This file is part of the GNU C Library.
00004 
00005    The GNU C Library is free software; you can redistribute it and/or
00006    modify it under the terms of the GNU Lesser General Public
00007    License as published by the Free Software Foundation; either
00008    version 2.1 of the License, or (at your option) any later version.
00009 
00010    The GNU C Library is distributed in the hope that it will be useful,
00011    but WITHOUT ANY WARRANTY; without even the implied warranty of
00012    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00013    Lesser General Public License for more details.
00014 
00015    You should have received a copy of the GNU Lesser General Public
00016    License along with the GNU C Library; if not, write to the Free
00017    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00018    02111-1307 USA.  */
00019 
00020 #ifndef _DL_SYSDEP_H
00021 #define _DL_SYSDEP_H 1
00022 
00023 /* This macro must be defined to either 0 or 1.
00024 
00025    If 1, then an errno global variable hidden in ld.so will work right with
00026    all the errno-using libc code compiled for ld.so, and there is never a
00027    need to share the errno location with libc.  This is appropriate only if
00028    all the libc functions that ld.so uses are called without PLT and always
00029    get the versions linked into ld.so rather than the libc ones.  */
00030 
00031 #ifdef IS_IN_rtld
00032 # define RTLD_PRIVATE_ERRNO 1
00033 #else
00034 # define RTLD_PRIVATE_ERRNO 0
00035 #endif
00036 
00037 /* Traditionally system calls have been made using int $0x80.  A
00038    second method was introduced which, if possible, will use the
00039    sysenter/syscall instructions.  To signal the presence and where to
00040    find the code the kernel passes an AT_SYSINFO value in the
00041    auxiliary vector to the application.
00042    sysenter/syscall is not useful on i386 through i586, but the dynamic
00043    linker and dl code in libc.a has to be able to load i686 compiled
00044    libraries.  */
00045 #define NEED_DL_SYSINFO     1
00046 #undef USE_DL_SYSINFO
00047 
00048 #if defined NEED_DL_SYSINFO && !defined __ASSEMBLER__
00049 extern void _dl_sysinfo_int80 (void) attribute_hidden;
00050 # define DL_SYSINFO_DEFAULT (uintptr_t) _dl_sysinfo_int80
00051 # define DL_SYSINFO_IMPLEMENTATION \
00052   asm (".text\n\t"                                                   \
00053        ".type _dl_sysinfo_int80,@function\n\t"                              \
00054        ".hidden _dl_sysinfo_int80\n\t"                                      \
00055        CFI_STARTPROC "\n"                                            \
00056        "_dl_sysinfo_int80:\n\t"                                             \
00057        "int $0x80;\n\t"                                                     \
00058        "ret;\n\t"                                                    \
00059        CFI_ENDPROC "\n"                                                     \
00060        ".size _dl_sysinfo_int80,.-_dl_sysinfo_int80\n\t"                    \
00061        ".previous;");
00062 #endif
00063 
00064 
00065 /* The _dl_discover_osversion function is so far only needed in sysconf
00066    to check for kernels later than 2.6.23.  */
00067 #if !defined __ASSEMBLER__ && __LINUX_KERNEL_VERSION < 0x020617
00068 /* Get version of the OS.  */
00069 extern int _dl_discover_osversion (void) attribute_hidden;
00070 # define HAVE_DL_DISCOVER_OSVERSION       1
00071 #endif
00072 
00073 #endif /* dl-sysdep.h */