Changeset 215634 in webkit for trunk/Source/JavaScriptCore/tools/SigillCrashAnalyzer.cpp

Timestamp:

Apr 21, 2017, 1:31:39 PM (8 years ago)

Author:

[email protected]

Message:

Unreviewed, rolling out r215620 and r215623.
​https://bugs.webkit.org/show_bug.cgi?id=171139

broke arm64 build (Requested by keith_miller on #webkit).

Reverted changesets:

"Add signaling API"
​https://bugs.webkit.org/show_bug.cgi?id=170976
​http://trac.webkit.org/changeset/215620

"Unreviewed, fix Cloop build."
​http://trac.webkit.org/changeset/215623

File:

• trunk/Source/JavaScriptCore/tools/SigillCrashAnalyzer.cpp (modified) (2 diffs)

trunk/Source/JavaScriptCore/tools/SigillCrashAnalyzer.cpp

@@ -38 +38 @@
 #endif
 
-#include <wtf/threads/Signals.h>
+#if HAVE(SIGNAL_H)
+#include <signal.h>
+#endif
 
 namespace JSC {
@@ -140 +142 @@
 };
 
+struct sigaction originalSigIllAction;
+
+static void handleCrash(int signalNumber, siginfo_t* info, void* uap)
+{
+    SignalContext context(static_cast<ucontext_t*>(uap)->uc_mcontext);
+    SigillCrashAnalyzer& analyzer = SigillCrashAnalyzer::instance();
+    auto crashSource = analyzer.analyze(context);
+
+    auto originalAction = originalSigIllAction.sa_sigaction;
+    if (originalAction) {
+        // It is always safe to just invoke the original handler using the sa_sigaction form
+        // without checking for the SA_SIGINFO flag. If the original handler is of the
+        // sa_handler form, it will just ignore the 2nd and 3rd arguments since sa_handler is a
+        // subset of sa_sigaction. This is what the man pages says the OS does anyway.
+        originalAction(signalNumber, info, uap);
+    }
+
+    if (crashSource == SigillCrashAnalyzer::CrashSource::JavaScriptCore) {
+        // Restore the default handler so that we can get a core dump.
+        struct sigaction defaultAction;
+        defaultAction.sa_handler = SIG_DFL;
+        sigfillset(&defaultAction.sa_mask);
+        defaultAction.sa_flags = 0;
+        sigaction(SIGILL, &defaultAction, nullptr);
+    } else if (!originalAction) {
+        // Pre-emptively restore the default handler but we may roll it back below.
+        struct sigaction currentAction;
+        struct sigaction defaultAction;
+        defaultAction.sa_handler = SIG_DFL;
+        sigfillset(&defaultAction.sa_mask);
+        defaultAction.sa_flags = 0;
+        sigaction(SIGILL, &defaultAction, &currentAction);
+
+        if (currentAction.sa_sigaction != handleCrash) {
+            // This means that there's a client handler installed after us. This also means
+            // that the client handler thinks it was able to recover from the SIGILL, and
+            // did not uninstall itself. We can't argue with this because the crash isn't
+            // known to be from a JavaScriptCore source. Hence, restore the client handler
+            // and keep going.
+            sigaction(SIGILL, &currentAction, nullptr);
+        }
+    }
+}
+
 static void installCrashHandler()
 {
 #if CPU(X86_64) || CPU(ARM64)
-    installSignalHandler(Signal::Ill, [] (int, siginfo_t*, void* uap) {
-        SignalContext context(static_cast<ucontext_t*>(uap)->uc_mcontext);
-
-        if (!isJITPC(context.machinePC))
-            return SignalAction::NotHandled;
-
-        SigillCrashAnalyzer& analyzer = SigillCrashAnalyzer::instance();
-        analyzer.analyze(context);
-        return SignalAction::NotHandled;
-    });
+    struct sigaction action;
+    action.sa_sigaction = reinterpret_cast<void (*)(int, siginfo_t *, void *)>(handleCrash);
+    sigfillset(&action.sa_mask);
+    action.sa_flags = SA_SIGINFO;
+    sigaction(SIGILL, &action, &originalSigIllAction);
+#else
+    UNUSED_PARAM(handleCrash);
 #endif
 }