fix sigaltstack to ignore ss_size with SS_DISABLE, per POSIX

diff --git a/src/signal/sigaltstack.c b/src/signal/sigaltstack.c
index cfa3f5c..d3a6e82 100644 (file)
--- a/src/signal/sigaltstack.c
+++ b/src/signal/sigaltstack.c
@@ -5,7 +5,7 @@
 int sigaltstack(const stack_t *restrict ss, stack_t *restrict old)
 {
        if (ss) {
-               if (ss->ss_size < MINSIGSTKSZ) {
+               if (!(ss->ss_flags & SS_DISABLE) && ss->ss_size < MINSIGSTKSZ) {
                        errno = ENOMEM;
                        return -1;
                }