c5c78a527d
The use of &[1]uintptr{fn} was causing sigfwd to allocate memory, even
though it is being compiled for the runtime package. That is a bad
idea for this function, which is invoked by a signal handler. Rewrite
it to use only constructs that do not allocate memory when compiled
for the runtime package.
The test for this is misc/cgo/testcarchive in the main repo, which we
don't yet test.
Reviewed-on: https://go-review.googlesource.com/37454
From-SVN: r245777
145 lines
3.3 KiB
Go
145 lines
3.3 KiB
Go
// Copyright 2016 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// +build darwin dragonfly freebsd linux netbsd openbsd solaris
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package runtime
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import (
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"unsafe"
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)
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// Functions for gccgo to support signal handling. In the gc runtime
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// these are written in OS-specific files and in assembler.
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//extern sigaction
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func sigaction(signum uint32, act *_sigaction, oact *_sigaction) int32
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//extern sigprocmask
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func sigprocmask(how int32, set *sigset, oldset *sigset) int32
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//extern sigfillset
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func sigfillset(set *sigset) int32
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//extern sigemptyset
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func sigemptyset(set *sigset) int32
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//extern sigaddset
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func c_sigaddset(set *sigset, signum uint32) int32
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//extern sigdelset
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func c_sigdelset(set *sigset, signum uint32) int32
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//extern sigaltstack
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func sigaltstack(ss *_stack_t, oss *_stack_t) int32
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//extern raise
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func raise(sig uint32) int32
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//extern getpid
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func getpid() _pid_t
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//extern kill
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func kill(pid _pid_t, sig uint32) int32
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//extern setitimer
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func setitimer(which int32, new *_itimerval, old *_itimerval) int32
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type sigTabT struct {
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flags int32
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name string
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}
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type sigctxt struct {
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info *_siginfo_t
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ctxt unsafe.Pointer
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}
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func (c *sigctxt) sigcode() uint64 {
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if c.info == nil {
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// This can happen on Solaris 10. We don't know the
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// code, just avoid a misleading value.
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return _SI_USER + 1
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}
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return uint64(c.info.si_code)
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}
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//go:nosplit
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//go:nowritebarrierrec
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func setsig(i uint32, fn uintptr) {
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var sa _sigaction
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sa.sa_flags = _SA_SIGINFO | _SA_RESTART
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// For gccgo we do not set SA_ONSTACK for a signal that can
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// cause a panic. Instead, we trust that the split stack has
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// enough room to start the signal handler. This is because
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// otherwise we have no good way to switch back to the
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// original stack before panicing.
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if sigtable[i].flags&_SigPanic == 0 {
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sa.sa_flags |= _SA_ONSTACK
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}
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sigfillset((*sigset)(unsafe.Pointer(&sa.sa_mask)))
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setSigactionHandler(&sa, fn)
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sigaction(i, &sa, nil)
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}
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//go:nosplit
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//go:nowritebarrierrec
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func setsigstack(i uint32) {
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var sa _sigaction
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sigaction(i, nil, &sa)
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handler := getSigactionHandler(&sa)
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if handler == 0 || handler == _SIG_DFL || handler == _SIG_IGN || sa.sa_flags&_SA_ONSTACK != 0 {
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return
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}
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if sigtable[i].flags&_SigPanic != 0 {
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return
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}
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sa.sa_flags |= _SA_ONSTACK
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sigaction(i, &sa, nil)
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}
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//go:nosplit
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//go:nowritebarrierrec
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func getsig(i uint32) uintptr {
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var sa _sigaction
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if sigaction(i, nil, &sa) < 0 {
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// On GNU/Linux glibc rejects attempts to call
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// sigaction with signal 32 (SIGCANCEL) or 33 (SIGSETXID).
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if GOOS == "linux" && (i == 32 || i == 33) {
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return _SIG_DFL
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}
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throw("sigaction read failure")
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}
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return getSigactionHandler(&sa)
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}
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func signalstack(p unsafe.Pointer, n uintptr)
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//go:nosplit
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//go:nowritebarrierrec
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func raiseproc(sig uint32) {
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kill(getpid(), sig)
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}
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//go:nosplit
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//go:nowritebarrierrec
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func sigfwd(fn uintptr, sig uint32, info *_siginfo_t, ctx unsafe.Pointer) {
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f1 := [1]uintptr{fn}
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f2 := &f1
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f3 := *(*func(uint32, *_siginfo_t, unsafe.Pointer))(unsafe.Pointer(&f2))
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f3(sig, info, ctx)
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}
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//go:nosplit
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//go:nowritebarrierrec
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func sigaddset(mask *sigset, i int) {
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c_sigaddset(mask, uint32(i))
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}
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func sigdelset(mask *sigset, i int) {
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c_sigdelset(mask, uint32(i))
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}
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