libgo/go/runtime/signal_sigtramp.go

   1 // Copyright 2009 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 dragonfly linux netbsd
   6
   7 package runtime
   8
   9 import "unsafe"
  10
  11 // Continuation of the (assembly) sigtramp() logic.
  12 // This may be called with the world stopped.
  13 //go:nosplit
  14 //go:nowritebarrierrec
  15 func sigtrampgo(sig uint32, info *siginfo, ctx unsafe.Pointer) {
  16         if sigfwdgo(sig, info, ctx) {
  17                 return
  18         }
  19         g := getg()
  20         if g == nil {
  21                 badsignal(uintptr(sig))
  22                 return
  23         }
  24
  25         // If some non-Go code called sigaltstack, adjust.
  26         sp := uintptr(unsafe.Pointer(&sig))
  27         if sp < g.m.gsignal.stack.lo || sp >= g.m.gsignal.stack.hi {
  28                 var st sigaltstackt
  29                 sigaltstack(nil, &st)
  30                 if st.ss_flags&_SS_DISABLE != 0 {
  31                         setg(nil)
  32                         cgocallback(unsafe.Pointer(funcPC(noSignalStack)), noescape(unsafe.Pointer(&sig)), unsafe.Sizeof(sig))
  33                 }
  34                 stsp := uintptr(unsafe.Pointer(st.ss_sp))
  35                 if sp < stsp || sp >= stsp+st.ss_size {
  36                         setg(nil)
  37                         cgocallback(unsafe.Pointer(funcPC(sigNotOnStack)), noescape(unsafe.Pointer(&sig)), unsafe.Sizeof(sig))
  38                 }
  39                 g.m.gsignal.stack.lo = stsp
  40                 g.m.gsignal.stack.hi = stsp + st.ss_size
  41                 g.m.gsignal.stackguard0 = stsp + _StackGuard
  42                 g.m.gsignal.stackguard1 = stsp + _StackGuard
  43                 g.m.gsignal.stackAlloc = st.ss_size
  44                 g.m.gsignal.stktopsp = getcallersp(unsafe.Pointer(&sig))
  45         }
  46
  47         setg(g.m.gsignal)
  48         sighandler(sig, info, ctx, g)
  49         setg(g)
  50 }