1 /* POSIX.1 `sigaction' call for Linux/i386.
2 Copyright (C) 1991-2016 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
26 #include <sys/syscall.h>
29 /* The difference here is that the sigaction structure used in the
30 kernel is not the same as we use in the libc. Therefore we must
32 #include <kernel_sigaction.h>
34 /* We do not globally define the SA_RESTORER flag so do it here. */
35 #define SA_RESTORER 0x04000000
38 /* Using the hidden attribute here does not change the code but it
39 helps to avoid warnings. */
40 #ifdef __NR_rt_sigaction
41 extern void restore_rt (void) asm ("__restore_rt") attribute_hidden
;
43 extern void restore (void) asm ("__restore") attribute_hidden
;
46 /* If ACT is not NULL, change the action for SIG to *ACT.
47 If OACT is not NULL, put the old action for SIG in *OACT. */
49 __libc_sigaction (int sig
, const struct sigaction
*act
, struct sigaction
*oact
)
53 struct kernel_sigaction kact
, koact
;
57 kact
.k_sa_handler
= act
->sa_handler
;
58 kact
.sa_flags
= act
->sa_flags
;
59 memcpy (&kact
.sa_mask
, &act
->sa_mask
, sizeof (sigset_t
));
61 if (GLRO(dl_sysinfo_dso
) == NULL
)
63 kact
.sa_flags
|= SA_RESTORER
;
65 kact
.sa_restorer
= ((act
->sa_flags
& SA_SIGINFO
)
66 ? &restore_rt
: &restore
);
70 /* XXX The size argument hopefully will have to be changed to the
71 real size of the user-level sigset_t. */
72 INTERNAL_SYSCALL_DECL (err
);
73 result
= INTERNAL_SYSCALL (rt_sigaction
, err
, 4,
74 sig
, act
? &kact
: NULL
,
75 oact
? &koact
: NULL
, _NSIG
/ 8);
76 if (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (result
, err
)))
77 return INLINE_SYSCALL_ERROR_RETURN_VALUE (INTERNAL_SYSCALL_ERRNO (result
,
79 else if (oact
&& result
>= 0)
81 oact
->sa_handler
= koact
.k_sa_handler
;
82 memcpy (&oact
->sa_mask
, &koact
.sa_mask
, sizeof (sigset_t
));
83 oact
->sa_flags
= koact
.sa_flags
;
84 oact
->sa_restorer
= koact
.sa_restorer
;
88 libc_hidden_def (__libc_sigaction
)
90 #include <nptl/sigaction.c>
92 /* NOTE: Please think twice before making any changes to the bits of
93 code below. GDB needs some intimate knowledge about it to
94 recognize them as signal trampolines, and make backtraces through
95 signal handlers work right. Important are both the names
96 (__restore and __restore_rt) and the exact instruction sequence.
97 If you ever feel the need to make any changes, please notify the
98 appropriate GDB maintainer. */
100 #define RESTORE(name, syscall) RESTORE2 (name, syscall)
101 #define RESTORE2(name, syscall) \
107 " movl $" #syscall ", %eax\n" \
111 #ifdef __NR_rt_sigaction
112 /* The return code for realtime-signals. */
113 RESTORE (restore_rt
, __NR_rt_sigreturn
)
116 /* For the boring old signals. */
118 #define RESTORE2(name, syscall) \
125 " movl $" #syscall ", %eax\n" \
129 RESTORE (restore
, __NR_sigreturn
)