1 files changed, 29 insertions, 0 deletions
diff --git a/libc/arch-arm/bionic/sigaction.c b/libc/arch-arm/bionic/sigaction.c
new file mode 100644
index 0000000..96ca7c6
--- /dev/null
+++ b/libc/arch-arm/bionic/sigaction.c
@@ -0,0 +1,29 @@
+#include <signal.h>
+
+extern int __sigaction(int signum, const struct sigaction *act, struct sigaction *oldact);
+extern void __sig_restorer();
+
+int sigaction(int signum, const struct sigaction *act, struct sigaction *oldact)
+{
+    struct sigaction real_act;
+
+    /* If the caller has not set a custom restorer, then set up a default one.
+     * The code will function properly without this, however GDB will not be
+     * able to recognize the stack frame as a signal trampoline, because it
+     * is hardcoded to look for the instruction sequence that glibc uses in
+     * its custom restorer.  By creating our own restorer with the same
+     * sequence, we ensure that GDB correctly identifies this as a signal
+     * trampoline frame.
+     *
+     * See http://sourceware.org/ml/gdb/2010-01/msg00143.html for more
+     * information on this.*/
+    if(act && !(act->sa_flags & SA_RESTORER)) {
+        real_act = *act;
+        real_act.sa_flags |= SA_RESTORER;
+        real_act.sa_restorer = __sig_restorer;
+
+        act = &real_act;
+    }
+
+    return __sigaction(signum, act, oldact);
+}