runtime: disable a signal by restoring the original disposition
Fixes #13034.
Fixes #13042.
Update #9896.
Change-Id: I189f381090223dd07086848aac2d69d2c00d80c4
Reviewed-on: https://go-review.googlesource.com/18062
Reviewed-by: Russ Cox <rsc@golang.org>
diff --git a/misc/cgo/testcarchive/main3.c b/misc/cgo/testcarchive/main3.c
new file mode 100644
index 0000000..2d3e565
--- /dev/null
+++ b/misc/cgo/testcarchive/main3.c
@@ -0,0 +1,153 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Test os/signal.Notify and os/signal.Reset.
+// This is a lot like misc/cgo/testcshared/main5.c.
+
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sched.h>
+
+#include "libgo3.h"
+
+static void die(const char* msg) {
+ perror(msg);
+ exit(EXIT_FAILURE);
+}
+
+static volatile sig_atomic_t sigioSeen;
+
+static void ioHandler(int signo, siginfo_t* info, void* ctxt) {
+ sigioSeen = 1;
+}
+
+int main(int argc, char** argv) {
+ int verbose;
+ struct sigaction sa;
+ int i;
+
+ verbose = argc > 2;
+ setvbuf(stdout, NULL, _IONBF, 0);
+
+ if (verbose) {
+ printf("calling sigaction\n");
+ }
+
+ memset(&sa, 0, sizeof sa);
+ sa.sa_sigaction = ioHandler;
+ if (sigemptyset(&sa.sa_mask) < 0) {
+ die("sigemptyset");
+ }
+ sa.sa_flags = SA_SIGINFO;
+ if (sigaction(SIGIO, &sa, NULL) < 0) {
+ die("sigaction");
+ }
+
+ // At this point there should not be a Go signal handler
+ // installed for SIGIO.
+
+ if (verbose) {
+ printf("raising SIGIO\n");
+ }
+
+ if (raise(SIGIO) < 0) {
+ die("raise");
+ }
+
+ if (verbose) {
+ printf("waiting for sigioSeen\n");
+ }
+
+ // Wait until the signal has been delivered.
+ i = 0;
+ while (!sigioSeen) {
+ if (sched_yield() < 0) {
+ perror("sched_yield");
+ }
+ i++;
+ if (i > 10000) {
+ fprintf(stderr, "looping too long waiting for signal\n");
+ exit(EXIT_FAILURE);
+ }
+ }
+
+ sigioSeen = 0;
+
+ // Tell the Go code to catch SIGIO.
+
+ if (verbose) {
+ printf("calling CatchSIGIO\n");
+ }
+
+ CatchSIGIO();
+
+ if (verbose) {
+ printf("raising SIGIO\n");
+ }
+
+ if (raise(SIGIO) < 0) {
+ die("raise");
+ }
+
+ if (verbose) {
+ printf("calling SawSIGIO\n");
+ }
+
+ if (!SawSIGIO()) {
+ fprintf(stderr, "Go handler did not see SIGIO\n");
+ exit(EXIT_FAILURE);
+ }
+
+ if (sigioSeen != 0) {
+ fprintf(stderr, "C handler saw SIGIO when only Go handler should have\n");
+ exit(EXIT_FAILURE);
+ }
+
+ // Tell the Go code to stop catching SIGIO.
+
+ if (verbose) {
+ printf("calling ResetSIGIO\n");
+ }
+
+ ResetSIGIO();
+
+ if (verbose) {
+ printf("raising SIGIO\n");
+ }
+
+ if (raise(SIGIO) < 0) {
+ die("raise");
+ }
+
+ if (verbose) {
+ printf("calling SawSIGIO\n");
+ }
+
+ if (SawSIGIO()) {
+ fprintf(stderr, "Go handler saw SIGIO after Reset\n");
+ exit(EXIT_FAILURE);
+ }
+
+ if (verbose) {
+ printf("waiting for sigioSeen\n");
+ }
+
+ // Wait until the signal has been delivered.
+ i = 0;
+ while (!sigioSeen) {
+ if (sched_yield() < 0) {
+ perror("sched_yield");
+ }
+ i++;
+ if (i > 10000) {
+ fprintf(stderr, "looping too long waiting for signal\n");
+ exit(EXIT_FAILURE);
+ }
+ }
+
+ printf("PASS\n");
+ return 0;
+}
diff --git a/misc/cgo/testcarchive/src/libgo3/libgo3.go b/misc/cgo/testcarchive/src/libgo3/libgo3.go
new file mode 100644
index 0000000..94e5d21
--- /dev/null
+++ b/misc/cgo/testcarchive/src/libgo3/libgo3.go
@@ -0,0 +1,44 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import "C"
+
+import (
+ "os"
+ "os/signal"
+ "syscall"
+ "time"
+)
+
+// The channel used to read SIGIO signals.
+var sigioChan chan os.Signal
+
+// CatchSIGIO starts catching SIGIO signals.
+//export CatchSIGIO
+func CatchSIGIO() {
+ sigioChan = make(chan os.Signal, 1)
+ signal.Notify(sigioChan, syscall.SIGIO)
+}
+
+// ResetSIGIO stops catching SIGIO signals.
+//export ResetSIGIO
+func ResetSIGIO() {
+ signal.Reset(syscall.SIGIO)
+}
+
+// SawSIGIO returns whether we saw a SIGIO within a brief pause.
+//export SawSIGIO
+func SawSIGIO() C.int {
+ select {
+ case <-sigioChan:
+ return 1
+ case <-time.After(100 * time.Millisecond):
+ return 0
+ }
+}
+
+func main() {
+}
diff --git a/misc/cgo/testcarchive/test.bash b/misc/cgo/testcarchive/test.bash
index d561c02..053833a 100755
--- a/misc/cgo/testcarchive/test.bash
+++ b/misc/cgo/testcarchive/test.bash
@@ -30,7 +30,7 @@
GOPATH=$(pwd) go install -buildmode=c-archive libgo
$(go env CC) $(go env GOGCCFLAGS) $ccargs -o testp main.c pkg/$(go env GOOS)_$(go env GOARCH)/libgo.a
if ! $bin arg1 arg2; then
- echo "FAIL test1"
+ echo "FAIL test1a"
status=1
fi
rm -f libgo.a libgo.h testp
@@ -41,7 +41,7 @@
GOPATH=$(pwd) go build -buildmode=c-archive src/libgo/libgo.go
$(go env CC) $(go env GOGCCFLAGS) $ccargs -o testp main.c libgo.a
if ! $bin arg1 arg2; then
- echo "FAIL test2"
+ echo "FAIL test1b"
status=1
fi
rm -f libgo.a libgo.h testp
@@ -49,24 +49,32 @@
GOPATH=$(pwd) go build -buildmode=c-archive -o libgo.a libgo
$(go env CC) $(go env GOGCCFLAGS) $ccargs -o testp main.c libgo.a
if ! $bin arg1 arg2; then
- echo "FAIL test3"
+ echo "FAIL test1c"
status=1
fi
rm -rf libgo.a libgo.h testp pkg
case "$(go env GOOS)/$(go env GOARCH)" in
"darwin/arm" | "darwin/arm64")
- echo "Skipping test4; see https://golang.org/issue/13701"
+ echo "Skipping test2; see https://golang.org/issue/13701"
;;
*)
GOPATH=$(pwd) go build -buildmode=c-archive -o libgo2.a libgo2
$(go env CC) $(go env GOGCCFLAGS) $ccargs -o testp main2.c libgo2.a
if ! $bin; then
- echo "FAIL test4"
+ echo "FAIL test2"
status=1
fi
rm -rf libgo2.a libgo2.h testp pkg
;;
esac
+GOPATH=$(pwd) go build -buildmode=c-archive -o libgo3.a libgo3
+$(go env CC) $(go env GOGCCFLAGS) $ccargs -o testp main3.c libgo3.a
+if ! $bin; then
+ echo "FAIL test3"
+ status=1
+fi
+rm -rf libgo3.a libgo3.h testp pkg
+
exit $status
diff --git a/misc/cgo/testcshared/main5.c b/misc/cgo/testcshared/main5.c
new file mode 100644
index 0000000..50ddb47
--- /dev/null
+++ b/misc/cgo/testcshared/main5.c
@@ -0,0 +1,197 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Test that a signal handler works in non-Go code when using
+// os/signal.Notify.
+// This is a lot like misc/cgo/testcarchive/main3.c.
+
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sched.h>
+#include <dlfcn.h>
+
+static void die(const char* msg) {
+ perror(msg);
+ exit(EXIT_FAILURE);
+}
+
+static volatile sig_atomic_t sigioSeen;
+
+static void ioHandler(int signo, siginfo_t* info, void* ctxt) {
+ sigioSeen = 1;
+}
+
+int main(int argc, char** argv) {
+ int verbose;
+ struct sigaction sa;
+ void* handle;
+ void (*fn1)(void);
+ int (*sawSIGIO)(void);
+ int i;
+
+ verbose = argc > 2;
+ setvbuf(stdout, NULL, _IONBF, 0);
+
+ if (verbose) {
+ printf("calling sigaction\n");
+ }
+
+ memset(&sa, 0, sizeof sa);
+ sa.sa_sigaction = ioHandler;
+ if (sigemptyset(&sa.sa_mask) < 0) {
+ die("sigemptyset");
+ }
+ sa.sa_flags = SA_SIGINFO;
+ if (sigaction(SIGIO, &sa, NULL) < 0) {
+ die("sigaction");
+ }
+
+ if (verbose) {
+ printf("calling dlopen\n");
+ }
+
+ handle = dlopen(argv[1], RTLD_NOW | RTLD_GLOBAL);
+ if (handle == NULL) {
+ fprintf(stderr, "%s\n", dlerror());
+ exit(EXIT_FAILURE);
+ }
+
+ // At this point there should not be a Go signal handler
+ // installed for SIGIO.
+
+ if (verbose) {
+ printf("raising SIGIO\n");
+ }
+
+ if (raise(SIGIO) < 0) {
+ die("raise");
+ }
+
+ if (verbose) {
+ printf("waiting for sigioSeen\n");
+ }
+
+ // Wait until the signal has been delivered.
+ i = 0;
+ while (!sigioSeen) {
+ if (sched_yield() < 0) {
+ perror("sched_yield");
+ }
+ i++;
+ if (i > 10000) {
+ fprintf(stderr, "looping too long waiting for signal\n");
+ exit(EXIT_FAILURE);
+ }
+ }
+
+ sigioSeen = 0;
+
+ // Tell the Go code to catch SIGIO.
+
+ if (verbose) {
+ printf("calling dlsym\n");
+ }
+
+ fn1 = (void(*)(void))dlsym(handle, "CatchSIGIO");
+ if (fn1 == NULL) {
+ fprintf(stderr, "%s\n", dlerror());
+ exit(EXIT_FAILURE);
+ }
+
+ if (verbose) {
+ printf("calling CatchSIGIO\n");
+ }
+
+ fn1();
+
+ if (verbose) {
+ printf("raising SIGIO\n");
+ }
+
+ if (raise(SIGIO) < 0) {
+ die("raise");
+ }
+
+ if (verbose) {
+ printf("calling dlsym\n");
+ }
+
+ // Check that the Go code saw SIGIO.
+ sawSIGIO = (int (*)(void))dlsym(handle, "SawSIGIO");
+ if (sawSIGIO == NULL) {
+ fprintf(stderr, "%s\n", dlerror());
+ exit(EXIT_FAILURE);
+ }
+
+ if (verbose) {
+ printf("calling SawSIGIO\n");
+ }
+
+ if (!sawSIGIO()) {
+ fprintf(stderr, "Go handler did not see SIGIO\n");
+ exit(EXIT_FAILURE);
+ }
+
+ if (sigioSeen != 0) {
+ fprintf(stderr, "C handler saw SIGIO when only Go handler should have\n");
+ exit(EXIT_FAILURE);
+ }
+
+ // Tell the Go code to stop catching SIGIO.
+
+ if (verbose) {
+ printf("calling dlsym\n");
+ }
+
+ fn1 = (void(*)(void))dlsym(handle, "ResetSIGIO");
+ if (fn1 == NULL) {
+ fprintf(stderr, "%s\n", dlerror());
+ exit(EXIT_FAILURE);
+ }
+
+ if (verbose) {
+ printf("calling ResetSIGIO\n");
+ }
+
+ fn1();
+
+ if (verbose) {
+ printf("raising SIGIO\n");
+ }
+
+ if (raise(SIGIO) < 0) {
+ die("raise");
+ }
+
+ if (verbose) {
+ printf("calling SawSIGIO\n");
+ }
+
+ if (sawSIGIO()) {
+ fprintf(stderr, "Go handler saw SIGIO after Reset\n");
+ exit(EXIT_FAILURE);
+ }
+
+ if (verbose) {
+ printf("waiting for sigioSeen\n");
+ }
+
+ // Wait until the signal has been delivered.
+ i = 0;
+ while (!sigioSeen) {
+ if (sched_yield() < 0) {
+ perror("sched_yield");
+ }
+ i++;
+ if (i > 10000) {
+ fprintf(stderr, "looping too long waiting for signal\n");
+ exit(EXIT_FAILURE);
+ }
+ }
+
+ printf("PASS\n");
+ return 0;
+}
diff --git a/misc/cgo/testcshared/src/libgo5/libgo5.go b/misc/cgo/testcshared/src/libgo5/libgo5.go
new file mode 100644
index 0000000..94e5d21
--- /dev/null
+++ b/misc/cgo/testcshared/src/libgo5/libgo5.go
@@ -0,0 +1,44 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import "C"
+
+import (
+ "os"
+ "os/signal"
+ "syscall"
+ "time"
+)
+
+// The channel used to read SIGIO signals.
+var sigioChan chan os.Signal
+
+// CatchSIGIO starts catching SIGIO signals.
+//export CatchSIGIO
+func CatchSIGIO() {
+ sigioChan = make(chan os.Signal, 1)
+ signal.Notify(sigioChan, syscall.SIGIO)
+}
+
+// ResetSIGIO stops catching SIGIO signals.
+//export ResetSIGIO
+func ResetSIGIO() {
+ signal.Reset(syscall.SIGIO)
+}
+
+// SawSIGIO returns whether we saw a SIGIO within a brief pause.
+//export SawSIGIO
+func SawSIGIO() C.int {
+ select {
+ case <-sigioChan:
+ return 1
+ case <-time.After(100 * time.Millisecond):
+ return 0
+ }
+}
+
+func main() {
+}
diff --git a/misc/cgo/testcshared/test.bash b/misc/cgo/testcshared/test.bash
index 162a62d..ac852a00 100755
--- a/misc/cgo/testcshared/test.bash
+++ b/misc/cgo/testcshared/test.bash
@@ -33,8 +33,9 @@
androidpath=/data/local/tmp/testcshared-$$
function cleanup() {
- rm -f libgo.$libext libgo2.$libext libgo4.$libext libgo.h libgo4.h
- rm -f testp testp2 testp3 testp4
+ rm -f libgo.$libext libgo2.$libext libgo4.$libext libgo5.$libext
+ rm -f libgo.h libgo4.h libgo5.h
+ rm -f testp testp2 testp3 testp4 testp5
rm -rf pkg "${goroot}/${installdir}"
if [ "$goos" == "android" ]; then
@@ -161,6 +162,21 @@
status=1
fi
+# test5: tests signal handlers with os/signal.Notify
+GOPATH=$(pwd) go build -buildmode=c-shared $suffix -o libgo5.$libext libgo5
+binpush libgo5.$libext
+$(go env CC) ${GOGCCFLAGS} -pthread -o testp5 main5.c -ldl
+binpush testp5
+output=$(run ./testp5 ./libgo5.$libext 2>&1)
+if test "$output" != "PASS"; then
+ echo "FAIL test5 got ${output}"
+ if test "$goos" != "android"; then
+ echo "re-running test5 in verbose mode"
+ ./testp5 ./libgo5.$libext verbose
+ fi
+ status=1
+fi
+
if test $status = 0; then
echo "ok"
fi
diff --git a/src/os/signal/doc.go b/src/os/signal/doc.go
index 4a6d1d5..b36c16c 100644
--- a/src/os/signal/doc.go
+++ b/src/os/signal/doc.go
@@ -162,13 +162,20 @@
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. TODO: Describe Notify behavior.
+not install any other signal handlers by default. If there is an
+existing signal handler, the Go runtime will turn on the SA_ONSTACK
+flag and otherwise keep the signal handler. If Notify is called for an
+asynchronous signal, a Go signal handler will be installed for that
+signal. If, later, Reset is called for that signal, the original
+handling for that signal will be reinstalled, restoring the non-Go
+signal handler if any.
-Go code built otherwise will install a signal handler for the
-asynchronous signals listed above, and save any existing signal
-handler. If a signal is delivered to a non-Go thread, it will act as
-described above, except that if there is an existing non-Go signal
-handler, that handler will be installed before raising the signal.
+Go code built without -buildmode=c-archive or -buildmode=c-shared will
+install a signal handler for the asynchronous signals listed above,
+and save any existing signal handler. If a signal is delivered to a
+non-Go thread, it will act as described above, except that if there is
+an existing non-Go signal handler, that handler will be installed
+before raising the signal.
Windows
diff --git a/src/runtime/runtime2.go b/src/runtime/runtime2.go
index 9549d1f..c357f6e 100644
--- a/src/runtime/runtime2.go
+++ b/src/runtime/runtime2.go
@@ -482,7 +482,6 @@
_SigPanic // if the signal is from the kernel, panic
_SigDefault // if the signal isn't explicitly requested, don't monitor it
_SigHandling // our signal handler is registered
- _SigIgnored // the signal was ignored before we registered for it
_SigGoExit // cause all runtime procs to exit (only used on Plan 9).
_SigSetStack // add SA_ONSTACK to libc handler
_SigUnblock // unblocked in minit
diff --git a/src/runtime/signal1_unix.go b/src/runtime/signal1_unix.go
index 3bb3ed8..468d6f6 100644
--- a/src/runtime/signal1_unix.go
+++ b/src/runtime/signal1_unix.go
@@ -49,13 +49,13 @@
continue
}
fwdSig[i] = getsig(i)
+
// For some signals, we respect an inherited SIG_IGN handler
// rather than insist on installing our own default handler.
// Even these signals can be fetched using the os/signal package.
switch i {
case _SIGHUP, _SIGINT:
- if getsig(i) == _SIG_IGN {
- t.flags = _SigNotify | _SigIgnored
+ if fwdSig[i] == _SIG_IGN {
continue
}
}
@@ -90,9 +90,6 @@
<-maskUpdatedChan
if t.flags&_SigHandling == 0 {
t.flags |= _SigHandling
- if getsig(int32(sig)) == _SIG_IGN {
- t.flags |= _SigIgnored
- }
setsig(int32(sig), funcPC(sighandler), true)
}
}
@@ -110,11 +107,7 @@
<-maskUpdatedChan
if t.flags&_SigHandling != 0 {
t.flags &^= _SigHandling
- if t.flags&_SigIgnored != 0 {
- setsig(int32(sig), _SIG_IGN, true)
- } else {
- setsig(int32(sig), _SIG_DFL, true)
- }
+ setsig(int32(sig), fwdSig[sig], true)
}
}
}
