diff options
authorRich Felker <>2019-03-05 11:02:15 -0500
committerRich Felker <>2019-03-05 11:08:46 -0500
commit4918b7fb0d9f3d3fd4b46be3313901fbd772064b (patch)
parent43e7efb46555f13a556d92944ac05c19b8929b60 (diff)
don't reject unknown/future flags in sigaltstack, allow SS_AUTODISARM
historically, and likely accidentally, sigaltstack was specified to fail with EINVAL if any flag bit other than SS_DISABLE was set. the resolution of Austin Group issue 1187 fixes this so that the requirement is only to fail for SS_ONSTACK (which cannot be set) or "invalid" flags. Linux fails on the kernel side for invalid flags, but historically accepts SS_ONSTACK as a no-op, so it needs to be rejected in userspace still. with this change, the Linux-specific SS_AUTODISARM, provided since commit 9680e1d03a794b0e0d5815c749478228ed40a36d but unusable due to rejection at runtime, is now usable.
1 files changed, 1 insertions, 1 deletions
diff --git a/src/signal/sigaltstack.c b/src/signal/sigaltstack.c
index 62cb81ad..cfa3f5c1 100644
--- a/src/signal/sigaltstack.c
+++ b/src/signal/sigaltstack.c
@@ -9,7 +9,7 @@ int sigaltstack(const stack_t *restrict ss, stack_t *restrict old)
errno = ENOMEM;
return -1;
- if (ss->ss_flags & ~SS_DISABLE) {
+ if (ss->ss_flags & SS_ONSTACK) {
errno = EINVAL;
return -1;