suppress gcc 8 aliasing warnings

function                                             old     new   delta
sigprocmask_SIG_SETMASK                                -      16     +16
wait_for_child_or_signal                             221     213      -8
dowait                                               432     424      -8

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

5 files changed, 25 insertions, 3 deletions

diff --git a/include/libbb.h b/include/libbb.h
index 9e0970095..638c58412 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -544,6 +544,8 @@ void sig_unblock(int sig) FAST_FUNC;
 int sigaction_set(int sig, const struct sigaction *act) FAST_FUNC;
 /* SIG_BLOCK/SIG_UNBLOCK all signals: */
 int sigprocmask_allsigs(int how) FAST_FUNC;
+/* SIG_SETMASK set, and return old set in the same set: */
+int sigprocmask_SIG_SETMASK(sigset_t *set) FAST_FUNC;
 /* Standard handler which just records signo */
 extern smallint bb_got_signal;
 void record_signo(int signo); /* not FAST_FUNC! */
diff --git a/libbb/lineedit.c b/libbb/lineedit.c
index b6fcd7af0..378f0900a 100644
--- a/libbb/lineedit.c
+++ b/libbb/lineedit.c
@@ -2309,6 +2309,16 @@ static int32_t reverse_i_search(int timeout)
 }
 #endif
 
+static void sigaction2(int sig, struct sigaction *act)
+{
+        // Grr... gcc 8.1.1:
+        // "passing argument 3 to restrict-qualified parameter aliases with argument 2"
+        // dance around that...
+        struct sigaction *oact FIX_ALIASING;
+        oact = act;
+        sigaction(sig, act, oact);
+}
+
 /* maxsize must be >= 2.
  * Returns:
  * -1 on read errors or EOF, or on bare Ctrl-D,
@@ -2419,7 +2429,7 @@ int FAST_FUNC read_line_input(line_input_t *st, const char *prompt, char *comman
         /* Install window resize handler (NB: after *all* init is complete) */
         S.SIGWINCH_handler.sa_handler = win_changed;
         S.SIGWINCH_handler.sa_flags = SA_RESTART;
-        sigaction(SIGWINCH, &S.SIGWINCH_handler, &S.SIGWINCH_handler);
+        sigaction2(SIGWINCH, &S.SIGWINCH_handler);
 #endif
         read_key_buffer[0] = 0;
         while (1) {
diff --git a/libbb/signals.c b/libbb/signals.c
index 3f589321c..5a1544db7 100644
--- a/libbb/signals.c
+++ b/libbb/signals.c
@@ -31,6 +31,16 @@ int FAST_FUNC sigprocmask_allsigs(int how)
         return sigprocmask(how, &set, NULL);
 }
 
+int FAST_FUNC sigprocmask_SIG_SETMASK(sigset_t *set)
+{
+        // Grr... gcc 8.1.1:
+        // "passing argument 3 to restrict-qualified parameter aliases with argument 2"
+        // dance around that...
+        sigset_t *oset FIX_ALIASING;
+        oset = set;
+        return sigprocmask(SIG_SETMASK, set, oset);
+}
+
 void FAST_FUNC bb_signals(int sigs, void (*f)(int))
 {
         int sig_no = 0;
diff --git a/shell/ash.c b/shell/ash.c
index 9ce1d1a76..456aca4f0 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -4217,7 +4217,7 @@ wait_block_or_sig(int *status)
                 /* Children exist, but none are ready. Sleep until interesting signal */
 #if 1
                 sigfillset(&mask);
-                sigprocmask(SIG_SETMASK, &mask, &mask);
+                sigprocmask_SIG_SETMASK(&mask); /* mask is updated */
                 while (!got_sigchld && !pending_sig)
                         sigsuspend(&mask);
                 sigprocmask(SIG_SETMASK, &mask, NULL);
diff --git a/shell/hush.c b/shell/hush.c
index 90191408d..5953ceb9f 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -11442,7 +11442,7 @@ static int wait_for_child_or_signal(struct pipe *waitfor_pipe, pid_t waitfor_pid
                  * and get stuck in sigsuspend...
                  */
                 sigfillset(&oldset); /* block all signals, remember old set */
-                sigprocmask(SIG_SETMASK, &oldset, &oldset);
+                sigprocmask_SIG_SETMASK(&oldset);
 
                 if (!sigisemptyset(&G.pending_set)) {
                         /* Crap! we raced with some signal! */