Block signals before invoking special or user handlers
1. Block signals marked in sa_mask before invoking user handler
if not in old style.
2. Block all signals before invoking special signal handler.
Change-Id: Ie1283e97ed28ee3421df584352cd62cb107264bc
Signed-off-by: jgu21 <jinghui.gu@intel.com>
diff --git a/sigchainlib/sigchain.cc b/sigchainlib/sigchain.cc
index c984b17..b76555b 100644
--- a/sigchainlib/sigchain.cc
+++ b/sigchainlib/sigchain.cc
@@ -150,10 +150,15 @@
// Do we have a managed handler? If so, run it first.
SpecialSignalHandlerFn managed = user_sigactions[sig].GetSpecialHandler();
if (managed != nullptr) {
+ sigset_t mask, old_mask;
+ sigfillset(&mask);
+ sigprocmask(SIG_BLOCK, &mask, &old_mask);
// Call the handler. If it succeeds, we're done.
if (managed(sig, info, context)) {
+ sigprocmask(SIG_SETMASK, &old_mask, nullptr);
return;
}
+ sigprocmask(SIG_SETMASK, &old_mask, nullptr);
}
const struct sigaction& action = user_sigactions[sig].GetAction();
@@ -166,7 +171,10 @@
}
} else {
if (action.sa_sigaction != nullptr) {
+ sigset_t old_mask;
+ sigprocmask(SIG_BLOCK, &action.sa_mask, &old_mask);
action.sa_sigaction(sig, info, context);
+ sigprocmask(SIG_SETMASK, &old_mask, nullptr);
} else {
signal(sig, SIG_DFL);
raise(sig);
diff --git a/test/115-native-bridge/nativebridge.cc b/test/115-native-bridge/nativebridge.cc
index 948273a..e9946c8 100644
--- a/test/115-native-bridge/nativebridge.cc
+++ b/test/115-native-bridge/nativebridge.cc
@@ -390,6 +390,20 @@
#endif
#endif
+static bool cannot_be_blocked(int signum) {
+ // These two sigs cannot be blocked anywhere.
+ if ((signum == SIGKILL) || (signum == SIGSTOP)) {
+ return true;
+ }
+
+ // The invalid rt_sig cannot be blocked.
+ if (((signum >= 32) && (signum < SIGRTMIN)) || (signum > SIGRTMAX)) {
+ return true;
+ }
+
+ return false;
+}
+
// A dummy special handler, continueing after the faulting location. This code comes from
// 004-SignalTest.
static bool nb_signalhandler(int sig, siginfo_t* info ATTRIBUTE_UNUSED, void* context) {
@@ -413,6 +427,23 @@
UNUSED(context);
#endif
}
+
+ // Before invoking this handler, all other unclaimed signals must be blocked.
+ // We're trying to check the signal mask to verify its status here.
+ sigset_t tmpset;
+ sigemptyset(&tmpset);
+ sigprocmask(SIG_SETMASK, nullptr, &tmpset);
+ int other_claimed = (sig == SIGSEGV) ? SIGILL : SIGSEGV;
+ for (int signum = 0; signum < NSIG; ++signum) {
+ if (cannot_be_blocked(signum)) {
+ continue;
+ } else if ((sigismember(&tmpset, signum)) && (signum == other_claimed)) {
+ printf("ERROR: The claimed signal %d is blocked\n", signum);
+ } else if ((!sigismember(&tmpset, signum)) && (signum != other_claimed)) {
+ printf("ERROR: The unclaimed signal %d is not blocked\n", signum);
+ }
+ }
+
// We handled this...
return true;
}