runtime: set SIGCONT to _SigNotify + _SigDefault

Use the current ability to say that we don't do anything with SIGCONT by
default, but programs can catch it using signal.Notify if they want.

Fixes #8953.

Change-Id: I67d40ce36a029cbc58a235cbe957335f4a58e1c5
Reviewed-on: https://go-review.googlesource.com/18185Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/os/signal/signal_test.go

@@ -278,3 +278,12 @@ func TestNohup(t *testing.T) {
 		}
 	}
 }
+
+// Test that SIGCONT works (issue 8953).
+func TestSIGCONT(t *testing.T) {
+	c := make(chan os.Signal, 1)
+	Notify(c, syscall.SIGCONT)
+	defer Stop(c)
+	syscall.Kill(syscall.Getpid(), syscall.SIGCONT)
+	waitSig(t, c, syscall.SIGCONT)
+}

src/runtime/signal_darwin.go

@@ -31,7 +31,7 @@ var sigtable = [...]sigTabT{
 	/* 16 */ {_SigNotify, "SIGURG: urgent condition on socket"},
 	/* 17 */ {0, "SIGSTOP: stop"},
 	/* 18 */ {_SigNotify + _SigDefault, "SIGTSTP: keyboard stop"},
-	/* 19 */ {0, "SIGCONT: continue after 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"},

src/runtime/signal_dragonfly.go

@@ -29,7 +29,7 @@ var sigtable = [...]sigTabT{
 	/* 16 */ {_SigNotify, "SIGURG: urgent condition on socket"},
 	/* 17 */ {0, "SIGSTOP: stop"},
 	/* 18 */ {_SigNotify + _SigDefault, "SIGTSTP: keyboard stop"},
-	/* 19 */ {0, "SIGCONT: continue after 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"},

src/runtime/signal_freebsd.go

@@ -31,7 +31,7 @@ var sigtable = [...]sigTabT{
 	/* 16 */ {_SigNotify, "SIGURG: urgent condition on socket"},
 	/* 17 */ {0, "SIGSTOP: stop"},
 	/* 18 */ {_SigNotify + _SigDefault, "SIGTSTP: keyboard stop"},
-	/* 19 */ {0, "SIGCONT: continue after 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"},

src/runtime/signal_nacl.go

@@ -29,7 +29,7 @@ var sigtable = [...]sigTabT{
 	/* 16 */ {_SigNotify, "SIGURG: urgent condition on socket"},
 	/* 17 */ {0, "SIGSTOP: stop"},
 	/* 18 */ {_SigNotify + _SigDefault, "SIGTSTP: keyboard stop"},
-	/* 19 */ {0, "SIGCONT: continue after 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"},

src/runtime/signal_netbsd.go

@@ -29,7 +29,7 @@ var sigtable = [...]sigTabT{
 	/* 16 */ {_SigNotify, "SIGURG: urgent condition on socket"},
 	/* 17 */ {0, "SIGSTOP: stop"},
 	/* 18 */ {_SigNotify + _SigDefault, "SIGTSTP: keyboard stop"},
-	/* 19 */ {0, "SIGCONT: continue after 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"},

src/runtime/signal_openbsd.go

@@ -31,7 +31,7 @@ var sigtable = [...]sigTabT{
 	/* 16 */ {_SigNotify, "SIGURG: urgent condition on socket"},
 	/* 17 */ {0, "SIGSTOP: stop"},
 	/* 18 */ {_SigNotify + _SigDefault, "SIGTSTP: keyboard stop"},
-	/* 19 */ {0, "SIGCONT: continue after 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"},

src/runtime/signal_solaris.go

@@ -35,7 +35,7 @@ var sigtable = [...]sigTabT{
 	/* 22 */ {_SigNotify, "SIGPOLL: pollable event occured"},
 	/* 23 */ {_SigNotify + _SigDefault, "SIGSTOP: stop (cannot be caught or ignored)"},
 	/* 24 */ {_SigNotify + _SigDefault, "SIGTSTP: user stop requested from tty"},
-	/* 25 */ {0, "SIGCONT: stopped process has been continued"},
+	/* 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"},
 	/* 28 */ {_SigNotify, "SIGVTALRM: virtual timer expired"},

src/runtime/sigtab_linux_generic.go

@@ -32,7 +32,7 @@ var sigtable = [...]sigTabT{
 	/* 15 */ {_SigNotify + _SigKill, "SIGTERM: termination"},
 	/* 16 */ {_SigThrow + _SigUnblock, "SIGSTKFLT: stack fault"},
 	/* 17 */ {_SigNotify + _SigUnblock, "SIGCHLD: child status has changed"},
-	/* 18 */ {0, "SIGCONT: continue"},
+	/* 18 */ {_SigNotify + _SigDefault, "SIGCONT: continue"},
 	/* 19 */ {0, "SIGSTOP: stop, unblockable"},
 	/* 20 */ {_SigNotify + _SigDefault, "SIGTSTP: keyboard stop"},
 	/* 21 */ {_SigNotify + _SigDefault, "SIGTTIN: background read from tty"},

src/runtime/sigtab_linux_mips64x.go

@@ -38,7 +38,7 @@ var sigtable = [...]sigTabT{
 	/* 22 */ {_SigNotify, "SIGIO: i/o now possible"},
 	/* 23 */ {0, "SIGSTOP: stop, unblockable"},
 	/* 24 */ {_SigNotify + _SigDefault, "SIGTSTP: keyboard stop"},
-	/* 25 */ {0, "SIGCONT: continue"},
+	/* 25 */ {_SigNotify + _SigDefault, "SIGCONT: continue"},
 	/* 26 */ {_SigNotify + _SigDefault, "SIGTTIN: background read from tty"},
 	/* 27 */ {_SigNotify + _SigDefault, "SIGTTOU: background write to tty"},
 	/* 28 */ {_SigNotify, "SIGVTALRM: virtual alarm clock"},