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// +build aix darwin dragonfly freebsd hurd linux netbsd openbsd solaris
6
7package runtime
8
9import (
10	"unsafe"
11)
12
13// Functions for gccgo to support signal handling. In the gc runtime
14// these are written in OS-specific files and in assembler.
15
16//go:noescape
17//extern sigaction
18func sigaction(signum uint32, act *_sigaction, oact *_sigaction) int32
19
20//go:noescape
21//extern sigprocmask
22func sigprocmask(how int32, set *sigset, oldset *sigset) int32
23
24//go:noescape
25//extern sigfillset
26func sigfillset(set *sigset) int32
27
28//go:noescape
29//extern sigemptyset
30func sigemptyset(set *sigset) int32
31
32//go:noescape
33//extern sigaddset
34func c_sigaddset(set *sigset, signum uint32) int32
35
36//go:noescape
37//extern sigdelset
38func c_sigdelset(set *sigset, signum uint32) int32
39
40//go:noescape
41//extern sigaltstack
42func sigaltstack(ss *_stack_t, oss *_stack_t) int32
43
44//extern raise
45func raise(sig uint32) int32
46
47//extern getpid
48func getpid() _pid_t
49
50//extern kill
51func kill(pid _pid_t, sig uint32) int32
52
53//go:noescape
54//extern setitimer
55func setitimer(which int32, new *_itimerval, old *_itimerval) int32
56
57type sigctxt struct {
58	info *_siginfo_t
59	ctxt unsafe.Pointer
60}
61
62func (c *sigctxt) sigcode() uint64 {
63	return uint64(getSiginfoCode(c.info))
64}
65
66//go:nosplit
67//go:nowritebarrierrec
68func setsig(i uint32, fn uintptr) {
69	var sa _sigaction
70	sa.sa_flags = _SA_SIGINFO | _SA_RESTART
71
72	// For gccgo we do not set SA_ONSTACK for a signal that can
73	// cause a panic.  Instead, we trust that the split stack has
74	// enough room to start the signal handler.  This is because
75	// otherwise we have no good way to switch back to the
76	// original stack before panicing.
77	if sigtable[i].flags&_SigPanic == 0 {
78		sa.sa_flags |= _SA_ONSTACK
79	}
80
81	sigfillset((*sigset)(unsafe.Pointer(&sa.sa_mask)))
82	setSigactionHandler(&sa, fn)
83	sigaction(i, &sa, nil)
84}
85
86//go:nosplit
87//go:nowritebarrierrec
88func setsigstack(i uint32) {
89	var sa _sigaction
90	sigaction(i, nil, &sa)
91	handler := getSigactionHandler(&sa)
92	if handler == 0 || handler == _SIG_DFL || handler == _SIG_IGN || sa.sa_flags&_SA_ONSTACK != 0 {
93		return
94	}
95	if sigtable[i].flags&_SigPanic != 0 {
96		return
97	}
98	sa.sa_flags |= _SA_ONSTACK
99	sigaction(i, &sa, nil)
100}
101
102//go:nosplit
103//go:nowritebarrierrec
104func getsig(i uint32) uintptr {
105	var sa _sigaction
106	if sigaction(i, nil, &sa) < 0 {
107		// On GNU/Linux glibc rejects attempts to call
108		// sigaction with signal 32 (SIGCANCEL) or 33 (SIGSETXID).
109		if GOOS == "linux" && (i == 32 || i == 33) {
110			return _SIG_DFL
111		}
112		throw("sigaction read failure")
113	}
114	return getSigactionHandler(&sa)
115}
116
117func signalstack(p unsafe.Pointer, n uintptr)
118
119//go:nosplit
120//go:nowritebarrierrec
121func raiseproc(sig uint32) {
122	kill(getpid(), sig)
123}
124
125//go:nosplit
126//go:nowritebarrierrec
127func sigfwd(fn uintptr, sig uint32, info *_siginfo_t, ctx unsafe.Pointer) {
128	f1 := [1]uintptr{fn}
129	f2 := &f1
130	f3 := *(*func(uint32, *_siginfo_t, unsafe.Pointer))(unsafe.Pointer(&f2))
131	f3(sig, info, ctx)
132}
133
134//go:nosplit
135//go:nowritebarrierrec
136func sigaddset(mask *sigset, i int) {
137	c_sigaddset(mask, uint32(i))
138}
139
140func sigdelset(mask *sigset, i int) {
141	c_sigdelset(mask, uint32(i))
142}
143