runtime: forward crashing signals to late handlers

CL 49590 made it possible for external signal handlers to catch
signals from a crashing Go process. This CL extends that support
to handlers registered after the Go runtime has initialized.

Updates #20392 (and possibly fix it).

Change-Id: I18eccd5e958a505f4d1782a7fc51c16bd3a4ff9c
Reviewed-on: https://go-review.googlesource.com/57291
Run-TryBot: Elias Naur <elias.naur@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

diff --git a/src/runtime/crash_cgo_test.go b/src/runtime/crash_cgo_test.go
index 2869ac768723e6e1b6ab8efd4d62a1637cf78e18..40d12dc3dd92bccf68ab58a1a9716303d1a3b0e3 100644 (file)
--- a/src/runtime/crash_cgo_test.go
+++ b/src/runtime/crash_cgo_test.go
@@ -430,12 +430,16 @@ func TestCatchPanic(t *testing.T) {
                t.Fatal(err)
        }
 
-       cmd := testEnv(exec.Command(exe, "CgoCatchPanic"))
-       // Make sure a panic results in a crash.
-       cmd.Env = append(cmd.Env, "GOTRACEBACK=crash")
-       // Tell testprogcgo to install an early signal handler for SIGABRT
-       cmd.Env = append(cmd.Env, "CGOCATCHPANIC_INSTALL_HANDLER=1")
-       if out, err := cmd.CombinedOutput(); err != nil {
-               t.Errorf("testprogcgo CgoCatchPanic failed: %v\n%s", err, out)
+       for _, early := range []bool{true, false} {
+               cmd := testEnv(exec.Command(exe, "CgoCatchPanic"))
+               // Make sure a panic results in a crash.
+               cmd.Env = append(cmd.Env, "GOTRACEBACK=crash")
+               if early {
+                       // Tell testprogcgo to install an early signal handler for SIGABRT
+                       cmd.Env = append(cmd.Env, "CGOCATCHPANIC_EARLY_HANDLER=1")
+               }
+               if out, err := cmd.CombinedOutput(); err != nil {
+                       t.Errorf("testprogcgo CgoCatchPanic failed: %v\n%s", err, out)
+               }
        }
 }

diff --git a/src/runtime/runtime2.go b/src/runtime/runtime2.go
index 366dfc9f4569245f140c793f71d25ce567f3c604..b439a3197600edd539172efa79594a248864ac90 100644 (file)
--- a/src/runtime/runtime2.go
+++ b/src/runtime/runtime2.go
@@ -604,6 +604,7 @@ const (
        _SigGoExit               // cause all runtime procs to exit (only used on Plan 9).
        _SigSetStack             // add SA_ONSTACK to libc handler
        _SigUnblock              // unblocked in minit
+       _SigIgn                  // _SIG_DFL action is to ignore the signal
 )
 
 // Layout of in-memory per-function information prepared by linker

diff --git a/src/runtime/signal_darwin.go b/src/runtime/signal_darwin.go
index 581b4d04fb926b525c4332588cc8e92f106ca57b..8090fb22a5cfd4e668f234a8d77ce7b51747bb82 100644 (file)
--- a/src/runtime/signal_darwin.go
+++ b/src/runtime/signal_darwin.go
@@ -21,20 +21,20 @@ var sigtable = [...]sigTabT{
        /* 13 */ {_SigNotify, "SIGPIPE: write to broken pipe"},
        /* 14 */ {_SigNotify, "SIGALRM: alarm clock"},
        /* 15 */ {_SigNotify + _SigKill, "SIGTERM: termination"},
-       /* 16 */ {_SigNotify, "SIGURG: urgent condition on socket"},
+       /* 16 */ {_SigNotify + _SigIgn, "SIGURG: urgent condition on socket"},
        /* 17 */ {0, "SIGSTOP: stop"},
-       /* 18 */ {_SigNotify + _SigDefault, "SIGTSTP: keyboard stop"},
-       /* 19 */ {_SigNotify + _SigDefault, "SIGCONT: continue after stop"},
-       /* 20 */ {_SigNotify + _SigUnblock, "SIGCHLD: child status has changed"},
-       /* 21 */ {_SigNotify + _SigDefault, "SIGTTIN: background read from tty"},
-       /* 22 */ {_SigNotify + _SigDefault, "SIGTTOU: background write to tty"},
-       /* 23 */ {_SigNotify, "SIGIO: i/o now possible"},
+       /* 18 */ {_SigNotify + _SigDefault + _SigIgn, "SIGTSTP: keyboard stop"},
+       /* 19 */ {_SigNotify + _SigDefault + _SigIgn, "SIGCONT: continue after stop"},
+       /* 20 */ {_SigNotify + _SigUnblock + _SigIgn, "SIGCHLD: child status has changed"},
+       /* 21 */ {_SigNotify + _SigDefault + _SigIgn, "SIGTTIN: background read from tty"},
+       /* 22 */ {_SigNotify + _SigDefault + _SigIgn, "SIGTTOU: background write to tty"},
+       /* 23 */ {_SigNotify + _SigIgn, "SIGIO: i/o now possible"},
        /* 24 */ {_SigNotify, "SIGXCPU: cpu limit exceeded"},
        /* 25 */ {_SigNotify, "SIGXFSZ: file size limit exceeded"},
        /* 26 */ {_SigNotify, "SIGVTALRM: virtual alarm clock"},
        /* 27 */ {_SigNotify + _SigUnblock, "SIGPROF: profiling alarm clock"},
-       /* 28 */ {_SigNotify, "SIGWINCH: window size change"},
-       /* 29 */ {_SigNotify, "SIGINFO: status request from keyboard"},
+       /* 28 */ {_SigNotify + _SigIgn, "SIGWINCH: window size change"},
+       /* 29 */ {_SigNotify + _SigIgn, "SIGINFO: status request from keyboard"},
        /* 30 */ {_SigNotify, "SIGUSR1: user-defined signal 1"},
        /* 31 */ {_SigNotify, "SIGUSR2: user-defined signal 2"},
 }

diff --git a/src/runtime/signal_dragonfly.go b/src/runtime/signal_dragonfly.go
index aae46e75d02a0c85e94bb4166c641171b6be061a..f2b26e71791251fae361e614c8886a45aba53e45 100644 (file)
--- a/src/runtime/signal_dragonfly.go
+++ b/src/runtime/signal_dragonfly.go
@@ -21,20 +21,20 @@ var sigtable = [...]sigTabT{
        /* 13 */ {_SigNotify, "SIGPIPE: write to broken pipe"},
        /* 14 */ {_SigNotify, "SIGALRM: alarm clock"},
        /* 15 */ {_SigNotify + _SigKill, "SIGTERM: termination"},
-       /* 16 */ {_SigNotify, "SIGURG: urgent condition on socket"},
+       /* 16 */ {_SigNotify + _SigIgn, "SIGURG: urgent condition on socket"},
        /* 17 */ {0, "SIGSTOP: stop"},
-       /* 18 */ {_SigNotify + _SigDefault, "SIGTSTP: keyboard stop"},
-       /* 19 */ {_SigNotify + _SigDefault, "SIGCONT: continue after stop"},
-       /* 20 */ {_SigNotify + _SigUnblock, "SIGCHLD: child status has changed"},
-       /* 21 */ {_SigNotify + _SigDefault, "SIGTTIN: background read from tty"},
-       /* 22 */ {_SigNotify + _SigDefault, "SIGTTOU: background write to tty"},
-       /* 23 */ {_SigNotify, "SIGIO: i/o now possible"},
+       /* 18 */ {_SigNotify + _SigDefault + _SigIgn, "SIGTSTP: keyboard stop"},
+       /* 19 */ {_SigNotify + _SigDefault + _SigIgn, "SIGCONT: continue after stop"},
+       /* 20 */ {_SigNotify + _SigUnblock + _SigIgn, "SIGCHLD: child status has changed"},
+       /* 21 */ {_SigNotify + _SigDefault + _SigIgn, "SIGTTIN: background read from tty"},
+       /* 22 */ {_SigNotify + _SigDefault + _SigIgn, "SIGTTOU: background write to tty"},
+       /* 23 */ {_SigNotify + _SigIgn, "SIGIO: i/o now possible"},
        /* 24 */ {_SigNotify, "SIGXCPU: cpu limit exceeded"},
        /* 25 */ {_SigNotify, "SIGXFSZ: file size limit exceeded"},
        /* 26 */ {_SigNotify, "SIGVTALRM: virtual alarm clock"},
        /* 27 */ {_SigNotify + _SigUnblock, "SIGPROF: profiling alarm clock"},
-       /* 28 */ {_SigNotify, "SIGWINCH: window size change"},
-       /* 29 */ {_SigNotify, "SIGINFO: status request from keyboard"},
+       /* 28 */ {_SigNotify + _SigIgn, "SIGWINCH: window size change"},
+       /* 29 */ {_SigNotify + _SigIgn, "SIGINFO: status request from keyboard"},
        /* 30 */ {_SigNotify, "SIGUSR1: user-defined signal 1"},
        /* 31 */ {_SigNotify, "SIGUSR2: user-defined signal 2"},
        /* 32 */ {_SigNotify, "SIGTHR: reserved"},

diff --git a/src/runtime/signal_freebsd.go b/src/runtime/signal_freebsd.go
index 0bbbd2a809d135804fa727bfec998173221638c4..2812c69989f466dd23b27427fe1942cfa9dd885c 100644 (file)
--- a/src/runtime/signal_freebsd.go
+++ b/src/runtime/signal_freebsd.go
@@ -21,20 +21,20 @@ var sigtable = [...]sigTabT{
        /* 13 */ {_SigNotify, "SIGPIPE: write to broken pipe"},
        /* 14 */ {_SigNotify, "SIGALRM: alarm clock"},
        /* 15 */ {_SigNotify + _SigKill, "SIGTERM: termination"},
-       /* 16 */ {_SigNotify, "SIGURG: urgent condition on socket"},
+       /* 16 */ {_SigNotify + _SigIgn, "SIGURG: urgent condition on socket"},
        /* 17 */ {0, "SIGSTOP: stop"},
-       /* 18 */ {_SigNotify + _SigDefault, "SIGTSTP: keyboard stop"},
-       /* 19 */ {_SigNotify + _SigDefault, "SIGCONT: continue after stop"},
-       /* 20 */ {_SigNotify + _SigUnblock, "SIGCHLD: child status has changed"},
-       /* 21 */ {_SigNotify + _SigDefault, "SIGTTIN: background read from tty"},
-       /* 22 */ {_SigNotify + _SigDefault, "SIGTTOU: background write to tty"},
-       /* 23 */ {_SigNotify, "SIGIO: i/o now possible"},
+       /* 18 */ {_SigNotify + _SigDefault + _SigIgn, "SIGTSTP: keyboard stop"},
+       /* 19 */ {_SigNotify + _SigDefault + _SigIgn, "SIGCONT: continue after stop"},
+       /* 20 */ {_SigNotify + _SigUnblock + _SigIgn, "SIGCHLD: child status has changed"},
+       /* 21 */ {_SigNotify + _SigDefault + _SigIgn, "SIGTTIN: background read from tty"},
+       /* 22 */ {_SigNotify + _SigDefault + _SigIgn, "SIGTTOU: background write to tty"},
+       /* 23 */ {_SigNotify + _SigIgn, "SIGIO: i/o now possible"},
        /* 24 */ {_SigNotify, "SIGXCPU: cpu limit exceeded"},
        /* 25 */ {_SigNotify, "SIGXFSZ: file size limit exceeded"},
        /* 26 */ {_SigNotify, "SIGVTALRM: virtual alarm clock"},
        /* 27 */ {_SigNotify + _SigUnblock, "SIGPROF: profiling alarm clock"},
-       /* 28 */ {_SigNotify, "SIGWINCH: window size change"},
-       /* 29 */ {_SigNotify, "SIGINFO: status request from keyboard"},
+       /* 28 */ {_SigNotify + _SigIgn, "SIGWINCH: window size change"},
+       /* 29 */ {_SigNotify + _SigIgn, "SIGINFO: status request from keyboard"},
        /* 30 */ {_SigNotify, "SIGUSR1: user-defined signal 1"},
        /* 31 */ {_SigNotify, "SIGUSR2: user-defined signal 2"},
        /* 32 */ {_SigNotify, "SIGTHR: reserved"},

diff --git a/src/runtime/signal_nacl.go b/src/runtime/signal_nacl.go
index 47930757da84dc9efdaddba03890225695595685..ad321d8b759b03e9156bdd89792a165c206d7c2e 100644 (file)
--- a/src/runtime/signal_nacl.go
+++ b/src/runtime/signal_nacl.go
@@ -26,13 +26,13 @@ var sigtable = [...]sigTabT{
        /* 13 */ {_SigNotify, "SIGPIPE: write to broken pipe"},
        /* 14 */ {_SigNotify, "SIGALRM: alarm clock"},
        /* 15 */ {_SigNotify + _SigKill, "SIGTERM: termination"},
-       /* 16 */ {_SigNotify, "SIGURG: urgent condition on socket"},
+       /* 16 */ {_SigNotify + _SigIgn, "SIGURG: urgent condition on socket"},
        /* 17 */ {0, "SIGSTOP: stop"},
-       /* 18 */ {_SigNotify + _SigDefault, "SIGTSTP: keyboard stop"},
-       /* 19 */ {_SigNotify + _SigDefault, "SIGCONT: continue after stop"},
-       /* 20 */ {_SigNotify, "SIGCHLD: child status has changed"},
-       /* 21 */ {_SigNotify + _SigDefault, "SIGTTIN: background read from tty"},
-       /* 22 */ {_SigNotify + _SigDefault, "SIGTTOU: background write to tty"},
+       /* 18 */ {_SigNotify + _SigDefault + _SigIgn, "SIGTSTP: keyboard stop"},
+       /* 19 */ {_SigNotify + _SigDefault + _SigIgn, "SIGCONT: continue after stop"},
+       /* 20 */ {_SigNotify + _SigIgn, "SIGCHLD: child status has changed"},
+       /* 21 */ {_SigNotify + _SigDefault + _SigIgn, "SIGTTIN: background read from tty"},
+       /* 22 */ {_SigNotify + _SigDefault + _SigIgn, "SIGTTOU: background write to tty"},
        /* 23 */ {_SigNotify, "SIGIO: i/o now possible"},
        /* 24 */ {_SigNotify, "SIGXCPU: cpu limit exceeded"},
        /* 25 */ {_SigNotify, "SIGXFSZ: file size limit exceeded"},

diff --git a/src/runtime/signal_netbsd.go b/src/runtime/signal_netbsd.go
index 32a9bb0b83c8bdf9cc48706d76987d9c38adde17..ca510842e192a8932368b0589e06a13d4888d870 100644 (file)
--- a/src/runtime/signal_netbsd.go
+++ b/src/runtime/signal_netbsd.go
@@ -21,20 +21,20 @@ var sigtable = [...]sigTabT{
        /* 13 */ {_SigNotify, "SIGPIPE: write to broken pipe"},
        /* 14 */ {_SigNotify, "SIGALRM: alarm clock"},
        /* 15 */ {_SigNotify + _SigKill, "SIGTERM: termination"},
-       /* 16 */ {_SigNotify, "SIGURG: urgent condition on socket"},
+       /* 16 */ {_SigNotify + _SigIgn, "SIGURG: urgent condition on socket"},
        /* 17 */ {0, "SIGSTOP: stop"},
-       /* 18 */ {_SigNotify + _SigDefault, "SIGTSTP: keyboard stop"},
-       /* 19 */ {_SigNotify + _SigDefault, "SIGCONT: continue after stop"},
-       /* 20 */ {_SigNotify + _SigUnblock, "SIGCHLD: child status has changed"},
-       /* 21 */ {_SigNotify + _SigDefault, "SIGTTIN: background read from tty"},
-       /* 22 */ {_SigNotify + _SigDefault, "SIGTTOU: background write to tty"},
-       /* 23 */ {_SigNotify, "SIGIO: i/o now possible"},
+       /* 18 */ {_SigNotify + _SigDefault + _SigIgn, "SIGTSTP: keyboard stop"},
+       /* 19 */ {_SigNotify + _SigDefault + _SigIgn, "SIGCONT: continue after stop"},
+       /* 20 */ {_SigNotify + _SigUnblock + _SigIgn, "SIGCHLD: child status has changed"},
+       /* 21 */ {_SigNotify + _SigDefault + _SigIgn, "SIGTTIN: background read from tty"},
+       /* 22 */ {_SigNotify + _SigDefault + _SigIgn, "SIGTTOU: background write to tty"},
+       /* 23 */ {_SigNotify + _SigIgn, "SIGIO: i/o now possible"},
        /* 24 */ {_SigNotify, "SIGXCPU: cpu limit exceeded"},
        /* 25 */ {_SigNotify, "SIGXFSZ: file size limit exceeded"},
        /* 26 */ {_SigNotify, "SIGVTALRM: virtual alarm clock"},
        /* 27 */ {_SigNotify + _SigUnblock, "SIGPROF: profiling alarm clock"},
-       /* 28 */ {_SigNotify, "SIGWINCH: window size change"},
-       /* 29 */ {_SigNotify, "SIGINFO: status request from keyboard"},
+       /* 28 */ {_SigNotify + _SigIgn, "SIGWINCH: window size change"},
+       /* 29 */ {_SigNotify + _SigIgn, "SIGINFO: status request from keyboard"},
        /* 30 */ {_SigNotify, "SIGUSR1: user-defined signal 1"},
        /* 31 */ {_SigNotify, "SIGUSR2: user-defined signal 2"},
        /* 32 */ {_SigNotify, "SIGTHR: reserved"},

diff --git a/src/runtime/signal_openbsd.go b/src/runtime/signal_openbsd.go
index 32a9bb0b83c8bdf9cc48706d76987d9c38adde17..99c601ce58a0cfa6cbec4de952513d7408c1a27c 100644 (file)
--- a/src/runtime/signal_openbsd.go
+++ b/src/runtime/signal_openbsd.go
@@ -21,13 +21,13 @@ var sigtable = [...]sigTabT{
        /* 13 */ {_SigNotify, "SIGPIPE: write to broken pipe"},
        /* 14 */ {_SigNotify, "SIGALRM: alarm clock"},
        /* 15 */ {_SigNotify + _SigKill, "SIGTERM: termination"},
-       /* 16 */ {_SigNotify, "SIGURG: urgent condition on socket"},
+       /* 16 */ {_SigNotify + _SigIgn, "SIGURG: urgent condition on socket"},
        /* 17 */ {0, "SIGSTOP: stop"},
-       /* 18 */ {_SigNotify + _SigDefault, "SIGTSTP: keyboard stop"},
-       /* 19 */ {_SigNotify + _SigDefault, "SIGCONT: continue after stop"},
-       /* 20 */ {_SigNotify + _SigUnblock, "SIGCHLD: child status has changed"},
-       /* 21 */ {_SigNotify + _SigDefault, "SIGTTIN: background read from tty"},
-       /* 22 */ {_SigNotify + _SigDefault, "SIGTTOU: background write to tty"},
+       /* 18 */ {_SigNotify + _SigDefault + _SigIgn, "SIGTSTP: keyboard stop"},
+       /* 19 */ {_SigNotify + _SigDefault + _SigIgn, "SIGCONT: continue after stop"},
+       /* 20 */ {_SigNotify + _SigUnblock + _SigIgn, "SIGCHLD: child status has changed"},
+       /* 21 */ {_SigNotify + _SigDefault + _SigIgn, "SIGTTIN: background read from tty"},
+       /* 22 */ {_SigNotify + _SigDefault + _SigIgn, "SIGTTOU: background write to tty"},
        /* 23 */ {_SigNotify, "SIGIO: i/o now possible"},
        /* 24 */ {_SigNotify, "SIGXCPU: cpu limit exceeded"},
        /* 25 */ {_SigNotify, "SIGXFSZ: file size limit exceeded"},

diff --git a/src/runtime/signal_solaris.go b/src/runtime/signal_solaris.go
index dc1db76406188a364b7b6a7d76b3ecddd3d9e76e..a8eeeee129e1f603fe4fb0b1932bdfd10e24e9c4 100644 (file)
--- a/src/runtime/signal_solaris.go
+++ b/src/runtime/signal_solaris.go
@@ -23,16 +23,16 @@ var sigtable = [...]sigTabT{
        /* 15 */ {_SigNotify + _SigKill, "SIGTERM: software termination signal from kill"},
        /* 16 */ {_SigNotify, "SIGUSR1: user defined signal 1"},
        /* 17 */ {_SigNotify, "SIGUSR2: user defined signal 2"},
-       /* 18 */ {_SigNotify + _SigUnblock, "SIGCHLD: child status change alias (POSIX)"},
+       /* 18 */ {_SigNotify + _SigUnblock + _SigIgn, "SIGCHLD: child status change alias (POSIX)"},
        /* 19 */ {_SigNotify, "SIGPWR: power-fail restart"},
-       /* 20 */ {_SigNotify, "SIGWINCH: window size change"},
-       /* 21 */ {_SigNotify, "SIGURG: urgent socket condition"},
+       /* 20 */ {_SigNotify + _SigIgn, "SIGWINCH: window size change"},
+       /* 21 */ {_SigNotify + _SigIgn, "SIGURG: urgent socket condition"},
        /* 22 */ {_SigNotify, "SIGPOLL: pollable event occurred"},
        /* 23 */ {0, "SIGSTOP: stop (cannot be caught or ignored)"},
-       /* 24 */ {_SigNotify + _SigDefault, "SIGTSTP: user stop requested from tty"},
-       /* 25 */ {_SigNotify + _SigDefault, "SIGCONT: stopped process has been continued"},
-       /* 26 */ {_SigNotify + _SigDefault, "SIGTTIN: background tty read attempted"},
-       /* 27 */ {_SigNotify + _SigDefault, "SIGTTOU: background tty write attempted"},
+       /* 24 */ {_SigNotify + _SigDefault + _SigIgn, "SIGTSTP: user stop requested from tty"},
+       /* 25 */ {_SigNotify + _SigDefault + _SigIgn, "SIGCONT: stopped process has been continued"},
+       /* 26 */ {_SigNotify + _SigDefault + _SigIgn, "SIGTTIN: background tty read attempted"},
+       /* 27 */ {_SigNotify + _SigDefault + _SigIgn, "SIGTTOU: background tty write attempted"},
        /* 28 */ {_SigNotify, "SIGVTALRM: virtual timer expired"},
        /* 29 */ {_SigNotify + _SigUnblock, "SIGPROF: profiling timer expired"},
        /* 30 */ {_SigNotify, "SIGXCPU: exceeded cpu limit"},

diff --git a/src/runtime/signal_unix.go b/src/runtime/signal_unix.go
index 973e5f924f1e88c03bcf9136e0d5691214735fee..5ea4b9f63157d450d385178f2a0015e88162be08 100644 (file)
--- a/src/runtime/signal_unix.go
+++ b/src/runtime/signal_unix.go
@@ -405,13 +405,8 @@ func sigpanic() {
 //go:nowritebarrierrec
 func dieFromSignal(sig uint32) {
        unblocksig(sig)
-       // First, try any signal handler installed before the runtime
-       // initialized.
-       fn := atomic.Loaduintptr(&fwdSig[sig])
-       // On Darwin, sigtramp is called even for non-Go signal handlers.
        // Mark the signal as unhandled to ensure it is forwarded.
        atomic.Store(&handlingSig[sig], 0)
-       setsig(sig, fn)
        raise(sig)
 
        // That should have killed us. On some systems, though, raise
@@ -601,17 +596,23 @@ func sigfwdgo(sig uint32, info *siginfo, ctx unsafe.Pointer) bool {
                return false
        }
        fwdFn := atomic.Loaduintptr(&fwdSig[sig])
+       flags := sigtable[sig].flags
 
-       if !signalsOK {
-               // The only way we can get here is if we are in a
-               // library or archive, we installed a signal handler
-               // at program startup, but the Go runtime has not yet
-               // been initialized.
+       // If we aren't handling the signal, forward it.
+       if atomic.Load(&handlingSig[sig]) == 0 || !signalsOK {
+               // If the signal is ignored, doing nothing is the same as forwarding.
+               if fwdFn == _SIG_IGN || (fwdFn == _SIG_DFL && flags&_SigIgn != 0) {
+                       return true
+               }
+               // We are not handling the signal and there is no other handler to forward to.
+               // Crash with the default behavior.
                if fwdFn == _SIG_DFL {
+                       setsig(sig, _SIG_DFL)
                        dieFromSignal(sig)
-               } else {
-                       sigfwd(fwdFn, sig, info, ctx)
+                       return false
                }
+
+               sigfwd(fwdFn, sig, info, ctx)
                return true
        }
 
@@ -620,18 +621,6 @@ func sigfwdgo(sig uint32, info *siginfo, ctx unsafe.Pointer) bool {
                return false
        }
 
-       // If we aren't handling the signal, forward it.
-       // Really if we aren't handling the signal, we shouldn't get here,
-       // but on Darwin setsigstack can lead us here because it sets
-       // the sa_tramp field. The sa_tramp field is not returned by
-       // sigaction, so the fix for that is non-obvious.
-       if atomic.Load(&handlingSig[sig]) == 0 {
-               sigfwd(fwdFn, sig, info, ctx)
-               return true
-       }
-
-       flags := sigtable[sig].flags
-
        c := &sigctxt{info, ctx}
        // Only forward synchronous signals and SIGPIPE.
        // Unfortunately, user generated SIGPIPEs will also be forwarded, because si_code

diff --git a/src/runtime/sigtab_linux_generic.go b/src/runtime/sigtab_linux_generic.go
index 9a8e58f49132df3514c0c28c6e1d4ac02fee7e7c..b26040b80317dbb98972db8835f1993a18171def 100644 (file)
--- a/src/runtime/sigtab_linux_generic.go
+++ b/src/runtime/sigtab_linux_generic.go
@@ -28,18 +28,18 @@ var sigtable = [...]sigTabT{
        /* 14 */ {_SigNotify, "SIGALRM: alarm clock"},
        /* 15 */ {_SigNotify + _SigKill, "SIGTERM: termination"},
        /* 16 */ {_SigThrow + _SigUnblock, "SIGSTKFLT: stack fault"},
-       /* 17 */ {_SigNotify + _SigUnblock, "SIGCHLD: child status has changed"},
-       /* 18 */ {_SigNotify + _SigDefault, "SIGCONT: continue"},
+       /* 17 */ {_SigNotify + _SigUnblock + _SigIgn, "SIGCHLD: child status has changed"},
+       /* 18 */ {_SigNotify + _SigDefault + _SigIgn, "SIGCONT: continue"},
        /* 19 */ {0, "SIGSTOP: stop, unblockable"},
-       /* 20 */ {_SigNotify + _SigDefault, "SIGTSTP: keyboard stop"},
-       /* 21 */ {_SigNotify + _SigDefault, "SIGTTIN: background read from tty"},
-       /* 22 */ {_SigNotify + _SigDefault, "SIGTTOU: background write to tty"},
-       /* 23 */ {_SigNotify, "SIGURG: urgent condition on socket"},
+       /* 20 */ {_SigNotify + _SigDefault + _SigIgn, "SIGTSTP: keyboard stop"},
+       /* 21 */ {_SigNotify + _SigDefault + _SigIgn, "SIGTTIN: background read from tty"},
+       /* 22 */ {_SigNotify + _SigDefault + _SigIgn, "SIGTTOU: background write to tty"},
+       /* 23 */ {_SigNotify + _SigIgn, "SIGURG: urgent condition on socket"},
        /* 24 */ {_SigNotify, "SIGXCPU: cpu limit exceeded"},
        /* 25 */ {_SigNotify, "SIGXFSZ: file size limit exceeded"},
        /* 26 */ {_SigNotify, "SIGVTALRM: virtual alarm clock"},
        /* 27 */ {_SigNotify + _SigUnblock, "SIGPROF: profiling alarm clock"},
-       /* 28 */ {_SigNotify, "SIGWINCH: window size change"},
+       /* 28 */ {_SigNotify + _SigIgn, "SIGWINCH: window size change"},
        /* 29 */ {_SigNotify, "SIGIO: i/o now possible"},
        /* 30 */ {_SigNotify, "SIGPWR: power failure restart"},
        /* 31 */ {_SigThrow, "SIGSYS: bad system call"},

diff --git a/src/runtime/sigtab_linux_mipsx.go b/src/runtime/sigtab_linux_mipsx.go
index 9f6e259cdb3c754e6b1bf92933459dd6b60c5499..81dd2314c566105278b2a0e8acf57874fec695a5 100644 (file)
--- a/src/runtime/sigtab_linux_mipsx.go
+++ b/src/runtime/sigtab_linux_mipsx.go
@@ -26,16 +26,16 @@ var sigtable = [...]sigTabT{
        /*  15 */ {_SigNotify + _SigKill, "SIGTERM: termination"},
        /*  16 */ {_SigNotify, "SIGUSR1: user-defined signal 1"},
        /*  17 */ {_SigNotify, "SIGUSR2: user-defined signal 2"},
-       /*  18 */ {_SigNotify + _SigUnblock, "SIGCHLD: child status has changed"},
+       /*  18 */ {_SigNotify + _SigUnblock + _SigIgn, "SIGCHLD: child status has changed"},
        /*  19 */ {_SigNotify, "SIGPWR: power failure restart"},
-       /*  20 */ {_SigNotify, "SIGWINCH: window size change"},
-       /*  21 */ {_SigNotify, "SIGURG: urgent condition on socket"},
+       /*  20 */ {_SigNotify + _SigIgn, "SIGWINCH: window size change"},
+       /*  21 */ {_SigNotify + _SigIgn, "SIGURG: urgent condition on socket"},
        /*  22 */ {_SigNotify, "SIGIO: i/o now possible"},
        /*  23 */ {0, "SIGSTOP: stop, unblockable"},
-       /*  24 */ {_SigNotify + _SigDefault, "SIGTSTP: keyboard stop"},
-       /*  25 */ {_SigNotify + _SigDefault, "SIGCONT: continue"},
-       /*  26 */ {_SigNotify + _SigDefault, "SIGTTIN: background read from tty"},
-       /*  27 */ {_SigNotify + _SigDefault, "SIGTTOU: background write to tty"},
+       /*  24 */ {_SigNotify + _SigDefault + _SigIgn, "SIGTSTP: keyboard stop"},
+       /*  25 */ {_SigNotify + _SigDefault + _SigIgn, "SIGCONT: continue"},
+       /*  26 */ {_SigNotify + _SigDefault + _SigIgn, "SIGTTIN: background read from tty"},
+       /*  27 */ {_SigNotify + _SigDefault + _SigIgn, "SIGTTOU: background write to tty"},
        /*  28 */ {_SigNotify, "SIGVTALRM: virtual alarm clock"},
        /*  29 */ {_SigNotify + _SigUnblock, "SIGPROF: profiling alarm clock"},
        /*  30 */ {_SigNotify, "SIGXCPU: cpu limit exceeded"},

diff --git a/src/runtime/testdata/testprogcgo/catchpanic.go b/src/runtime/testdata/testprogcgo/catchpanic.go
index f03b6d3ea36a70b35c6f74991d5cf91d653ac7a1..55a606d1bc854db2bc4400bd6ece42e120373e1d 100644 (file)
--- a/src/runtime/testdata/testprogcgo/catchpanic.go
+++ b/src/runtime/testdata/testprogcgo/catchpanic.go
@@ -17,17 +17,21 @@ static void abrthandler(int signum) {
        }
 }
 
-static void __attribute__ ((constructor)) sigsetup(void) {
+void registerAbortHandler() {
        struct sigaction act;
-
-       if (getenv("CGOCATCHPANIC_INSTALL_HANDLER") == NULL)
-               return;
        memset(&act, 0, sizeof act);
        act.sa_handler = abrthandler;
        sigaction(SIGABRT, &act, NULL);
 }
+
+static void __attribute__ ((constructor)) sigsetup(void) {
+       if (getenv("CGOCATCHPANIC_EARLY_HANDLER") == NULL)
+               return;
+       registerAbortHandler();
+}
 */
 import "C"
+import "os"
 
 func init() {
        register("CgoCatchPanic", CgoCatchPanic)
@@ -35,5 +39,8 @@ func init() {
 
 // Test that the SIGABRT raised by panic can be caught by an early signal handler.
 func CgoCatchPanic() {
+       if _, ok := os.LookupEnv("CGOCATCHPANIC_EARLY_HANDLER"); !ok {
+               C.registerAbortHandler()
+       }
        panic("catch me")
 }