skalibs

commit 61e06f3b12afe464c3b4fcd23d4a3a07251c50ac
parent 2abc3b2c555d3dd6f9707b4e866d7984ad9048d6
Author: Laurent Bercot <ska-skaware@skarnet.org>
Date:   Sat,  3 Sep 2022 10:22:33 +0000

 Include mitigation for BSD disease in sigaction wrapper

Signed-off-by: Laurent Bercot <ska@appnovation.com>

Diffstat:
M
src/libstddjb/sig_catch.c
 | 
16
+++++++++++++++-

1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/src/libstddjb/sig_catch.c b/src/libstddjb/sig_catch.c
@@ -2,14 +2,28 @@
 
 /* MT-unsafe */
 
+#include <skalibs/nonposix.h>
+#include <skalibs/bsdsnowflake.h>
+
 #include <signal.h>
+#include <errno.h>
 
 #include <skalibs/functypes.h>
 #include <skalibs/sig.h>
+#include <skalibs/nsig.h>
+
+ /*
+   BSD fails sigaction() with EINVAL on non-catchable signals, whereas
+   every reasonable OS succeeds and simply ignores the signal handler.
+ */
 
 int sig_catch (int sig, sig_func_ref f)
 {
   struct sigaction action = { .sa_handler = f, .sa_flags = SA_RESTART | SA_NOCLDSTOP } ;
   sigfillset(&action.sa_mask) ;
-  return sigaction(sig, &action, 0) >= 0 ;
+  return sigaction(sig, &action, 0) >= 0
+#ifdef SKALIBS_BSD_SUCKS
+ || (errno == EINVAL && sig >= 1 && sig <= NSIG)
+#endif
+ ;
 }