libgo/go/runtime/signal_gccgo.go

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