1 // Copyright 2016 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
4
5 //go:build linux && (amd64 || arm64 || ppc64le)
6
7 #include <errno.h>
8 #include <stddef.h>
9 #include <stdint.h>
10 #include <string.h>
11 #include <signal.h>
12
13 #include "libcgo.h"
14
15 // go_sigaction_t is a C version of the sigactiont struct from
16 // defs_linux_amd64.go. This definition — and its conversion to and from struct
17 // sigaction — are specific to linux/amd64.
18 typedef struct {
19 uintptr_t handler;
20 uint64_t flags;
21 uintptr_t restorer;
22 uint64_t mask;
23 } go_sigaction_t;
24
25 // SA_RESTORER is part of the kernel interface.
26 // This is Linux i386/amd64 specific.
27 #ifndef SA_RESTORER
28 #define SA_RESTORER 0x4000000
29 #endif
30
31 int32_t
x_cgo_sigaction(intptr_t signum,const go_sigaction_t * goact,go_sigaction_t * oldgoact)32 x_cgo_sigaction(intptr_t signum, const go_sigaction_t *goact, go_sigaction_t *oldgoact) {
33 int32_t ret;
34 struct sigaction act;
35 struct sigaction oldact;
36 size_t i;
37
38 _cgo_tsan_acquire();
39
40 memset(&act, 0, sizeof act);
41 memset(&oldact, 0, sizeof oldact);
42
43 if (goact) {
44 if (goact->flags & SA_SIGINFO) {
45 act.sa_sigaction = (void(*)(int, siginfo_t*, void*))(goact->handler);
46 } else {
47 act.sa_handler = (void(*)(int))(goact->handler);
48 }
49 sigemptyset(&act.sa_mask);
50 for (i = 0; i < 8 * sizeof(goact->mask); i++) {
51 if (goact->mask & ((uint64_t)(1)<<i)) {
52 sigaddset(&act.sa_mask, (int)(i+1));
53 }
54 }
55 act.sa_flags = (int)(goact->flags & ~(uint64_t)SA_RESTORER);
56 }
57
58 ret = sigaction((int)signum, goact ? &act : NULL, oldgoact ? &oldact : NULL);
59 if (ret == -1) {
60 // runtime.rt_sigaction expects _cgo_sigaction to return errno on error.
61 _cgo_tsan_release();
62 return errno;
63 }
64
65 if (oldgoact) {
66 if (oldact.sa_flags & SA_SIGINFO) {
67 oldgoact->handler = (uintptr_t)(oldact.sa_sigaction);
68 } else {
69 oldgoact->handler = (uintptr_t)(oldact.sa_handler);
70 }
71 oldgoact->mask = 0;
72 for (i = 0; i < 8 * sizeof(oldgoact->mask); i++) {
73 if (sigismember(&oldact.sa_mask, (int)(i+1)) == 1) {
74 oldgoact->mask |= (uint64_t)(1)<<i;
75 }
76 }
77 oldgoact->flags = (uint64_t)oldact.sa_flags;
78 }
79
80 _cgo_tsan_release();
81 return ret;
82 }
83