signal-util: make -1 termination of ignore_signals() argument list unnecessary

Clean up ignore_signals() + default_signals() + sigaction_many() a bit:
make it unnecessary to explicitly terminate the signal list with -1.
Merge all three calls into a single function that is just called with
slightly different parameters. And eliminate an unnecessary extra
iteration in its inner for() loop.

No change in behaviour.

src/basic/signal-util.c

@@ -45,11 +45,14 @@ int reset_signal_mask(void) {
         return 0;
 }
 
-static int sigaction_many_ap(const struct sigaction *sa, int sig, va_list ap) {
-        int r = 0;
+int sigaction_many_internal(const struct sigaction *sa, ...) {
+        int sig, r = 0;
+        va_list ap;
+
+        va_start(ap, sa);
 
         /* negative signal ends the list. 0 signal is skipped. */
-        for (; sig >= 0; sig = va_arg(ap, int)) {
+        while ((sig = va_arg(ap, int)) >= 0) {
 
                 if (sig == 0)
                         continue;
@@ -60,49 +63,6 @@ static int sigaction_many_ap(const struct sigaction *sa, int sig, va_list ap) {
                 }
         }
 
-        return r;
-}
-
-int sigaction_many(const struct sigaction *sa, ...) {
-        va_list ap;
-        int r;
-
-        va_start(ap, sa);
-        r = sigaction_many_ap(sa, 0, ap);
-        va_end(ap);
-
-        return r;
-}
-
-int ignore_signals(int sig, ...) {
-
-        static const struct sigaction sa = {
-                .sa_handler = SIG_IGN,
-                .sa_flags = SA_RESTART,
-        };
-
-        va_list ap;
-        int r;
-
-        va_start(ap, sig);
-        r = sigaction_many_ap(&sa, sig, ap);
-        va_end(ap);
-
-        return r;
-}
-
-int default_signals(int sig, ...) {
-
-        static const struct sigaction sa = {
-                .sa_handler = SIG_DFL,
-                .sa_flags = SA_RESTART,
-        };
-
-        va_list ap;
-        int r;
-
-        va_start(ap, sig);
-        r = sigaction_many_ap(&sa, sig, ap);
         va_end(ap);
 
         return r;

src/basic/signal-util.h

@@ -8,9 +8,28 @@
 int reset_all_signal_handlers(void);
 int reset_signal_mask(void);
 
-int ignore_signals(int sig, ...);
-int default_signals(int sig, ...);
-int sigaction_many(const struct sigaction *sa, ...);
+int sigaction_many_internal(const struct sigaction *sa, ...);
+
+#define ignore_signals(...)                                             \
+        sigaction_many_internal(                                        \
+                        &(const struct sigaction) {                     \
+                                .sa_handler = SIG_IGN,                  \
+                                .sa_flags = SA_RESTART                  \
+                        },                                              \
+                        __VA_ARGS__,                                    \
+                        -1)
+
+#define default_signals(...)                                            \
+        sigaction_many_internal(                                        \
+                        &(const struct sigaction) {                     \
+                                .sa_handler = SIG_DFL,                  \
+                                .sa_flags = SA_RESTART                  \
+                        },                                              \
+                        __VA_ARGS__,                                    \
+                        -1)
+
+#define sigaction_many(sa, ...)                                         \
+        sigaction_many_internal(sa, __VA_ARGS__, -1)
 
 int sigset_add_many(sigset_t *ss, ...);
 int sigprocmask_many(int how, sigset_t *old, ...);