1/* Copyright (C) 2001-2022 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
17
18#include <sysdep.h>
19#include <errno.h>
20#include <tls.h>
21
22#if IS_IN (rtld)
23# include <dl-sysdep.h> /* Defines RTLD_PRIVATE_ERRNO. */
24#endif
25
26.globl C_SYMBOL_NAME(errno)
27.globl syscall_error
28
29__syscall_error:
30#if defined (EWOULDBLOCK_sys) && EWOULDBLOCK_sys != EAGAIN
31 /* We translate the system's EWOULDBLOCK error into EAGAIN.
32 The GNU C library always defines EWOULDBLOCK==EAGAIN.
33 EWOULDBLOCK_sys is the original number. */
34 cmp $EWOULDBLOCK_sys, %RAX_LP /* Is it the old EWOULDBLOCK? */
35 jne notb /* Branch if not. */
36 movl $EAGAIN, %eax /* Yes; translate it to EAGAIN. */
37notb:
38#endif
39#ifdef PIC
40 movq C_SYMBOL_NAME(errno@GOTTPOFF)(%rip), %rcx
41 movl %eax, %fs:0(%rcx)
42#else
43 movl %eax, %fs:C_SYMBOL_NAME(errno@TPOFF)
44#endif
45 or $-1, %RAX_LP
46 ret
47
48#undef __syscall_error
49END (__syscall_error)
50

source code of glibc/sysdeps/unix/x86_64/sysdep.S