commit 28ea229bb29f3ee82991ca8b5ac5f7a9b7b89fdc
author Elliott Hughes <enh@google.com> Thu Sep 04 13:54:42 2014 -0700
committer Elliott Hughes <enh@google.com> Tue Oct 28 07:55:53 2014 -0700
tree 4b8588f24a00a676465e76dd539e4a3268870516
parent 8eb8c3929974060e0d8b5063886d6ed250198d41

Don't mask out SA_RESTORER from sa_flags.

glibc doesn't do this, and we probably shouldn't either.

Bug: 16703540
Bug: 17436734

(cherry picked from commit afe58ad9892de27a7acb0aaded6312ee0f958314)

Change-Id: Iada5d0ae814f438cb276f056b2b5e3675f0e3666

libc/bionic/sigaction.cpp

diff --git a/libc/bionic/sigaction.cpp b/libc/bionic/sigaction.cpp
index 9038bd5..0633748 100644
--- a/libc/bionic/sigaction.cpp
+++ b/libc/bionic/sigaction.cpp
@@ -69,10 +69,6 @@
     bionic_old_action->sa_mask = kernel_old_action.sa_mask;
 #if defined(SA_RESTORER)
     bionic_old_action->sa_restorer = kernel_old_action.sa_restorer;
-
-    if (bionic_old_action->sa_restorer == &__rt_sigreturn) {
-      bionic_old_action->sa_flags &= ~SA_RESTORER;
-    }
 #endif
   }
 

tests/signal_test.cpp

diff --git a/tests/signal_test.cpp b/tests/signal_test.cpp
index 89b8088..e53fd3a 100644
--- a/tests/signal_test.cpp
+++ b/tests/signal_test.cpp
@@ -14,10 +14,10 @@
  * limitations under the License.
  */
 
-#include <gtest/gtest.h>
+#include <signal.h>
 
 #include <errno.h>
-#include <signal.h>
+#include <gtest/gtest.h>
 
 #include "ScopedSignalHandler.h"
 
@@ -198,13 +198,19 @@
 static void EmptySignalAction(int, siginfo_t*, void*) {}
 
 TEST(signal, sigaction) {
+  // Both bionic and glibc set SA_RESTORER when talking to the kernel on arm,
+  // arm64, x86, and x86-64. The version of glibc we're using also doesn't
+  // define SA_RESTORER, but luckily it's the same value everywhere, and mips
+  // doesn't use the bit for anything.
+  static const int sa_restorer = 0x4000000;
+
   // See what's currently set for SIGALRM.
   struct sigaction original_sa;
   memset(&original_sa, 0, sizeof(original_sa));
   ASSERT_EQ(0, sigaction(SIGALRM, NULL, &original_sa));
   ASSERT_TRUE(original_sa.sa_handler == NULL);
   ASSERT_TRUE(original_sa.sa_sigaction == NULL);
-  ASSERT_TRUE(original_sa.sa_flags == 0);
+  ASSERT_EQ(0, original_sa.sa_flags & ~sa_restorer);
 
   // Set a traditional sa_handler signal handler.
   struct sigaction sa;
@@ -219,7 +225,7 @@
   ASSERT_EQ(0, sigaction(SIGALRM, NULL, &sa));
   ASSERT_TRUE(sa.sa_handler == EmptySignalHandler);
   ASSERT_TRUE((void*) sa.sa_sigaction == (void*) sa.sa_handler);
-  ASSERT_TRUE(sa.sa_flags == SA_ONSTACK);
+  ASSERT_EQ(SA_ONSTACK, sa.sa_flags & ~sa_restorer);
 
   // Set a new-style sa_sigaction signal handler.
   memset(&sa, 0, sizeof(sa));
@@ -233,7 +239,7 @@
   ASSERT_EQ(0, sigaction(SIGALRM, NULL, &sa));
   ASSERT_TRUE(sa.sa_sigaction == EmptySignalAction);
   ASSERT_TRUE((void*) sa.sa_sigaction == (void*) sa.sa_handler);
-  ASSERT_TRUE(sa.sa_flags == (SA_ONSTACK | SA_SIGINFO));
+  ASSERT_EQ((SA_ONSTACK | SA_SIGINFO), sa.sa_flags & ~sa_restorer);
 
   // Put everything back how it was.
   ASSERT_EQ(0, sigaction(SIGALRM, &original_sa, NULL));