Add multi-personality support to stack_t decoding

stack_t is one of many structures that contain members
whose size differs between 32-bit and 64-bit personalities.

* signal.c (print_stack_t): Decode 32-bit stack_t on a 64-bit host.

Reported-by: Elliott Hughes <enh@google.com>

1 files changed, 24 insertions, 1 deletions

diff --git a/signal.c b/signal.c
index a13f7ac..436039b 100644
--- a/signal.c
+++ b/signal.c
@@ -1084,10 +1084,33 @@ static void
 print_stack_t(struct tcb *tcp, unsigned long addr)
 {
 	stack_t ss;
+	int r;
 
 	if (!addr) {
 		tprints("NULL");
-	} else if (umove(tcp, addr, &ss) < 0) {
+		return;
+	}
+
+#if SUPPORTED_PERSONALITIES > 1 && SIZEOF_LONG > 4
+	if (current_wordsize != sizeof(ss.ss_sp) && current_wordsize == 4) {
+		struct {
+			uint32_t ss_sp;
+			int32_t ss_flags;
+			uint32_t ss_size;
+		} ss32;
+		r = umove(tcp, addr, &ss32);
+		if (r >= 0) {
+			memset(&ss, 0, sizeof(ss));
+			ss.ss_sp = (void*)(unsigned long) ss32.ss_sp;
+			ss.ss_flags = ss32.ss_flags;
+			ss.ss_size = (unsigned long) ss32.ss_size;
+		}
+	} else
+#endif
+	{
+		r = umove(tcp, addr, &ss);
+	}
+	if (r < 0) {
 		tprintf("%#lx", addr);
 	} else {
 		tprintf("{ss_sp=%#lx, ss_flags=", (unsigned long) ss.ss_sp);