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);
         }