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authorLaurent Bercot <ska-skaware@skarnet.org>2020-02-26 17:18:47 +0000
committerLaurent Bercot <ska-skaware@skarnet.org>2020-02-26 17:18:47 +0000
commit37e31f79514acfdff8ede65b73542b7abb1e61a5 (patch)
tree7c1048a43d048d9811736d16399bfca0afdd84a6 /src/libstddjb/selfpipe_trapset.c
parentab9c34c0e7b6a6abc8374b0e5f6515c75342239e (diff)
downloadskalibs-37e31f79514acfdff8ede65b73542b7abb1e61a5.tar.xz
Explicitly unblock signals when selfpiped without signalfd
This is arguably a bugfix, since selfpipe without signalfd relies on signals being actually delivered, and a process may have inherited a nonempty sigprocmask. Also use SIG_BLOCK instead of SIG_SETMASK when using selfpipe_trapset() with signalfd, because we shouldn't unblock signals that may have previously been blocked. This is also arguably a bugfix. This commit is essential for using the version of s6-linux-init that blocks SIGINT before disablecad on kernels without signalfd. Without it, SIGINT never gets unblocked, so it's never delivered to s6-svscan.
Diffstat (limited to 'src/libstddjb/selfpipe_trapset.c')
-rw-r--r--src/libstddjb/selfpipe_trapset.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/src/libstddjb/selfpipe_trapset.c b/src/libstddjb/selfpipe_trapset.c
index ad5ba10..542ad10 100644
--- a/src/libstddjb/selfpipe_trapset.c
+++ b/src/libstddjb/selfpipe_trapset.c
@@ -14,7 +14,7 @@ int selfpipe_trapset (sigset_t const *set)
{
sigset_t old ;
if (selfpipe_fd < 0) return (errno = EBADF, -1) ;
- if (sigprocmask(SIG_SETMASK, set, &old) < 0) return -1 ;
+ if (sigprocmask(SIG_BLOCK, set, &old) < 0) return -1 ;
if (signalfd(selfpipe_fd, set, SFD_NONBLOCK | SFD_CLOEXEC) < 0)
{
int e = errno ;
@@ -53,7 +53,7 @@ int selfpipe_trapset (sigset_t const *set)
if (sig_restore(i) < 0) break ;
}
}
- if (i < SKALIBS_NSIG)
+ if (i < SKALIBS_NSIG || sigprocmask(SIG_UNBLOCK, set, 0) < 0)
{
int e = errno ;
sig_restoreto(set, i) ;