Revert "runtime: handle SIGPIPE in c-archive and c-shared programs"

This reverts commit d24b57a6a1a3530e590b7c0a72dc78043e198630.

Reason for revert: Further complications arised (issue 18100). We'll try again in Go 1.9.

Change-Id: I5ca93d2643a4be877dd9c2d8df3359718440f02f
Reviewed-on: https://go-review.googlesource.com/33770
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Minux Ma <minux@golang.org>
Run-TryBot: Minux Ma <minux@golang.org>

2 files changed, 8 insertions, 15 deletions

diff --git a/src/os/signal/doc.go b/src/os/signal/doc.go
index 16f49c7ab8..73b01a2764 100644
--- a/src/os/signal/doc.go
+++ b/src/os/signal/doc.go
@@ -181,11 +181,10 @@ If the Go runtime sees an existing signal handler for the SIGCANCEL or
 SIGSETXID signals (which are used only on GNU/Linux), it will turn on
 the SA_ONSTACK flag and otherwise keep the signal handler.
 
-For the synchronous signals and SIGPIPE, the Go runtime will install a
-signal handler. It will save any existing signal handler. If a
-synchronous signal arrives while executing non-Go code, the Go runtime
-will invoke the existing signal handler instead of the Go signal
-handler.
+For the synchronous signals, the Go runtime will install a signal
+handler. It will save any existing signal handler. If a synchronous
+signal arrives while executing non-Go code, the Go runtime will invoke
+the existing signal handler instead of the Go signal handler.
 
 Go code built with -buildmode=c-archive or -buildmode=c-shared will
 not install any other signal handlers by default. If there is an
diff --git a/src/runtime/signal_unix.go b/src/runtime/signal_unix.go
index 78381e58d7..19173ac211 100644
--- a/src/runtime/signal_unix.go
+++ b/src/runtime/signal_unix.go
@@ -111,8 +111,8 @@ func sigInstallGoHandler(sig uint32) bool {
 	}
 
 	// When built using c-archive or c-shared, only install signal
-	// handlers for synchronous signals and SIGPIPE.
-	if (isarchive || islibrary) && t.flags&_SigPanic == 0 && sig != _SIGPIPE {
+	// handlers for synchronous signals.
+	if (isarchive || islibrary) && t.flags&_SigPanic == 0 {
 		return false
 	}
 
@@ -497,15 +497,9 @@ func sigfwdgo(sig uint32, info *siginfo, ctx unsafe.Pointer) bool {
 		return true
 	}
 
+	// Only forward synchronous signals.
 	c := &sigctxt{info, ctx}
-	// Only forward signals from the kernel.
-	// On Linux and Darwin there is no way to distinguish a SIGPIPE raised by a write
-	// to a closed socket or pipe from a SIGPIPE raised by kill or pthread_kill
-	// so we'll treat every SIGPIPE as kernel-generated.
-	userSig := c.sigcode() == _SI_USER &&
-		(sig != _SIGPIPE || GOOS != "linux" && GOOS != "android" && GOOS != "darwin")
-	// Only forward synchronous signals and SIGPIPE.
-	if userSig || flags&_SigPanic == 0 && sig != _SIGPIPE {
+	if c.sigcode() == _SI_USER || flags&_SigPanic == 0 {
 		return false
 	}
 	// Determine if the signal occurred inside Go code. We test that: