X-Git-Url: https://git.saurik.com/apple/libplatform.git/blobdiff_plain/89154bfbfa86dc8977dc06e4201daac587013ec8..HEAD:/src/setjmp/generic/sigtramp.c

diff --git a/src/setjmp/generic/sigtramp.c b/src/setjmp/generic/sigtramp.c
index 32e31db..ce9f505 100644
--- a/src/setjmp/generic/sigtramp.c
+++ b/src/setjmp/generic/sigtramp.c
@@ -44,9 +44,9 @@ extern int __sigreturn(ucontext_t *, int, uintptr_t);
  * Note that the kernel saves/restores all of our register state.
  */
 
-/* On i386, i386/sys/_sigtramp.s defines this. There is no in_sigtramp on arm */
-#if defined(__DYNAMIC__) && defined(__x86_64__)
-OS_NOEXPORT
+/* On i386, i386/sys/_sigtramp.s defines this. */
+#if defined(__DYNAMIC__) && !defined(__i386__)
+OS_NOEXPORT int __in_sigtramp;
 int __in_sigtramp = 0;
 #endif
 
@@ -72,7 +72,7 @@ _sigunaltstack(int set)
 {
         /* sigreturn(uctx, ctxstyle); */
 	/* syscall (SYS_SIGRETURN, uctx, ctxstyle); */
-	__sigreturn (NULL, (set == SS_ONSTACK) ? UC_SET_ALT_STACK : UC_RESET_ALT_STACK, 0);
+	__sigreturn (NULL, (set & SS_ONSTACK) ? UC_SET_ALT_STACK : UC_RESET_ALT_STACK, 0);
 }
 
 /* On these architectures, _sigtramp is implemented in assembly to
@@ -88,21 +88,37 @@ _sigtramp(
 	ucontext_t		*uctx,
 	uintptr_t		token
 ) {
+	__in_sigtramp = sig;
 	int ctxstyle = UC_FLAVOR;
 
-	if (sigstyle == UC_TRAD)
-		sa_handler(sig);
-	else {
+	/* Some variants are not supposed to get the last 2 parameters but it's
+	 * easier to pass them along - especially on arm64 whereby the extra fields
+	 * are probably in caller save registers anyways, thereby making no
+	 * difference to callee if we populate them or not.
+	 *
+	 *
+	 * Moreover, sigaction(2)'s man page implies that the following behavior
+	 * should be supported:
+	 *
+	 *      If the SA_SIGINFO flag is not set, the handler function should match
+	 *      either the ANSI C or traditional BSD prototype and be pointed to by
+	 *      the sa_handler member of struct sigaction.  In practice, FreeBSD
+	 *      always sends the three arguments of the latter and since the ANSI C
+	 *      prototype is a subset, both will work.
+	 *
+	 * See <rdar://problem/51448812> bad siginfo struct sent to SIGCHILD signal
+	 * handler in arm64 process
+	 */
 #if TARGET_OS_WATCH
-		// <rdar://problem/22016014>
-		sa_sigaction(sig, sinfo, NULL);
+	// <rdar://problem/22016014>
+	sa_sigaction(sig, sinfo, NULL);
 #else
-		sa_sigaction(sig, sinfo, uctx);
+	sa_sigaction(sig, sinfo, uctx);
 #endif
-	}
 
-        /* sigreturn(uctx, ctxstyle); */
+	/* sigreturn(uctx, ctxstyle); */
 	/* syscall (SYS_SIGRETURN, uctx, ctxstyle); */
+	__in_sigtramp = 0;
 	__sigreturn (uctx, ctxstyle, token);
 	__builtin_trap(); /* __sigreturn returning is a fatal error */
 }