libbb: introduse and use signal_[no_]SA_RESTART_empty_mask and sigaction_set

signal_SA_RESTART_empty_mask                           -      65     +65
signal_no_SA_RESTART_empty_mask                        -      54     +54
dd_main                                             1325    1369     +44
sigaction_set                                          -      19     +19
dname_enc                                            373     377      +4
UNSPEC_print                                          64      66      +2
setsignal                                            296     294      -2
bb_signals_recursive                                  95      92      -3
bb_askpass                                           367     361      -6
inetd_main                                          1810    1797     -13
rx_main                                              912     883     -29
sigdelset                                             32       -     -32
__sigdelset                                           32       -     -32
__GI_sigdelset                                        32       -     -32
sighup_handler                                        84      37     -47
arping_main                                         1844    1797     -47
fsck_main                                           1869    1807     -62
run_list                                            1917    1844     -73
vlock_main                                           492     409     -83
progressmeter                                        883     798     -85
handle_incoming_and_exit                            2737    2651     -86
------------------------------------------------------------------------------
(add/remove: 3/3 grow/shrink: 3/12 up/down: 188/-632)        Total: -444 bytes

4 files changed, 12 insertions, 38 deletions

diff --git a/networking/arping.c b/networking/arping.c
index c89b97567..2277ec55e 100644
--- a/networking/arping.c
+++ b/networking/arping.c
@@ -377,18 +377,8 @@ int arping_main(int argc, char **argv)
 		printf(" from %s via %s\n", inet_ntoa(src), device);
 	}
 
-	{
-		struct sigaction sa;
-
-		memset(&sa, 0, sizeof(sa));
-		sa.sa_flags = SA_RESTART;
-
-		sa.sa_handler = (void (*)(int)) finish;
-		sigaction(SIGINT, &sa, NULL);
-
-		sa.sa_handler = (void (*)(int)) catcher;
-		sigaction(SIGALRM, &sa, NULL);
-	}
+	signal_SA_RESTART_empty_mask(SIGINT,  (void (*)(int))finish);
+	signal_SA_RESTART_empty_mask(SIGALRM, (void (*)(int))catcher);
 
 	catcher();
 
diff --git a/networking/httpd.c b/networking/httpd.c
index e9137287c..7b7446ed9 100644
--- a/networking/httpd.c
+++ b/networking/httpd.c
@@ -1788,7 +1788,6 @@ static void handle_incoming_and_exit(const len_and_sockaddr *fromAddr)
 	char *header_ptr = header_ptr;
 	Htaccess_Proxy *proxy_entry;
 #endif
-	struct sigaction sa;
 #if ENABLE_FEATURE_HTTPD_BASIC_AUTH
 	int credentials = -1;  /* if not required this is Ok */
 #endif
@@ -1819,11 +1818,7 @@ static void handle_incoming_and_exit(const len_and_sockaddr *fromAddr)
 	}
 
 	/* Install timeout handler */
-	memset(&sa, 0, sizeof(sa));
-	sa.sa_handler = exit_on_signal;
-	/* sigemptyset(&sa.sa_mask); - memset should be enough */
-	/*sa.sa_flags = 0; - no SA_RESTART */
-	sigaction(SIGALRM, &sa, NULL);
+	signal_no_SA_RESTART_empty_mask(SIGALRM, exit_on_signal);
 	alarm(HEADER_READ_TIMEOUT);
 
 	if (!get_line()) /* EOF or error or empty line */
@@ -2247,15 +2242,9 @@ static void mini_httpd_inetd(void)
 #if ENABLE_FEATURE_HTTPD_RELOAD_CONFIG_SIGHUP
 static void sighup_handler(int sig)
 {
-	struct sigaction sa;
-
 	parse_conf(default_path_httpd_conf, sig == SIGHUP ? SIGNALED_PARSE : FIRST_PARSE);
 
-	memset(&sa, 0, sizeof(sa));
-	sa.sa_handler = sighup_handler;
-	/*sigemptyset(&sa.sa_mask); - memset should be enough */
-	sa.sa_flags = SA_RESTART;
-	sigaction(SIGHUP, &sa, NULL);
+	signal_SA_RESTART_empty_mask(SIGHUP, sighup_handler);
 }
 #endif
 
diff --git a/networking/inetd.c b/networking/inetd.c
index 463c7cfcf..196f6d29d 100644
--- a/networking/inetd.c
+++ b/networking/inetd.c
@@ -1179,15 +1179,15 @@ int inetd_main(int argc, char **argv)
 	sigaddset(&sa.sa_mask, SIGCHLD);
 	sigaddset(&sa.sa_mask, SIGHUP);
 	sa.sa_handler = retry_network_setup;
-	sigaction(SIGALRM, &sa, NULL);
+	sigaction_set(SIGALRM, &sa);
 	sa.sa_handler = reread_config_file;
-	sigaction(SIGHUP, &sa, NULL);
+	sigaction_set(SIGHUP, &sa);
 	sa.sa_handler = reap_child;
-	sigaction(SIGCHLD, &sa, NULL);
+	sigaction_set(SIGCHLD, &sa);
 	sa.sa_handler = clean_up_and_exit;
-	sigaction(SIGTERM, &sa, NULL);
+	sigaction_set(SIGTERM, &sa);
 	sa.sa_handler = clean_up_and_exit;
-	sigaction(SIGINT, &sa, NULL);
+	sigaction_set(SIGINT, &sa);
 	sa.sa_handler = SIG_IGN;
 	sigaction(SIGPIPE, &sa, &saved_pipe_handler);
 
@@ -1382,7 +1382,7 @@ int inetd_main(int argc, char **argv)
 			 * for nowait stream children */
 			for (sep2 = serv_list; sep2; sep2 = sep2->se_next)
 				maybe_close(sep2->se_fd);
-			sigaction(SIGPIPE, &saved_pipe_handler, NULL);
+			sigaction_set(SIGPIPE, &saved_pipe_handler);
 			unblock_sigs(&omask);
 			BB_EXECVP(sep->se_program, sep->se_argv);
 			bb_perror_msg("exec %s", sep->se_program);
diff --git a/networking/wget.c b/networking/wget.c
index 36a83560a..a77a2add7 100644
--- a/networking/wget.c
+++ b/networking/wget.c
@@ -144,13 +144,8 @@ static void progressmeter(int flag)
 		transferred = 0;
 		fputc('\n', stderr);
 	} else {
-		if (flag == -1) {
-			/* first call to progressmeter */
-			struct sigaction sa;
-			sa.sa_handler = progressmeter;
-			sigemptyset(&sa.sa_mask);
-			sa.sa_flags = SA_RESTART;
-			sigaction(SIGALRM, &sa, NULL);
+		if (flag == -1) { /* first call to progressmeter */
+			signal_SA_RESTART_empty_mask(SIGALRM, progressmeter);
 		}
 		alarm(1);
 	}