passt: Fix error check for signal(), improve error messages

Valtteri reports that if SIGPIPE already has a disposition set by the
parent process, such as systemd with the default setting of
IgnoreSIGPIPE=yes, signal() will return the previous value, not zero,
and this is not an error: check for SIG_ERR instead.

While at it, split messages for failures of sigaction() and signal(),
and report the actual error.

Reported-by: Valtteri Vuorikoski <vuori@notcom.org>
Fixes: 8534be076c73 ("Catch failures when installing signal handlers")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

0 files changed, 0 insertions, 0 deletions