github.com/q45/go@v0.0.0-20151101211701-a4fb8c13db3f/src/runtime/signal2_unix.go (about)

     1  // Copyright 2012 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 darwin linux
     6  
     7  package runtime
     8  
     9  import "unsafe"
    10  
    11  //go:noescape
    12  func sigfwd(fn uintptr, sig uint32, info *siginfo, ctx unsafe.Pointer)
    13  
    14  // Determines if the signal should be handled by Go and if not, forwards the
    15  // signal to the handler that was installed before Go's.  Returns whether the
    16  // signal was forwarded.
    17  //go:nosplit
    18  func sigfwdgo(sig uint32, info *siginfo, ctx unsafe.Pointer) bool {
    19  	g := getg()
    20  	c := &sigctxt{info, ctx}
    21  	if sig >= uint32(len(sigtable)) {
    22  		return false
    23  	}
    24  	fwdFn := fwdSig[sig]
    25  	flags := sigtable[sig].flags
    26  
    27  	// If there is no handler to forward to, no need to forward.
    28  	if fwdFn == _SIG_DFL {
    29  		return false
    30  	}
    31  	// Only forward synchronous signals.
    32  	if c.sigcode() == _SI_USER || flags&_SigPanic == 0 {
    33  		return false
    34  	}
    35  	// Determine if the signal occurred inside Go code.  We test that:
    36  	//   (1) we were in a goroutine (i.e., m.curg != nil), and
    37  	//   (2) we weren't in CGO (i.e., m.curg.syscallsp == 0).
    38  	if g != nil && g.m != nil && g.m.curg != nil && g.m.curg.syscallsp == 0 {
    39  		return false
    40  	}
    41  	// Signal not handled by Go, forward it.
    42  	if fwdFn != _SIG_IGN {
    43  		sigfwd(fwdFn, sig, info, ctx)
    44  	}
    45  	return true
    46  }