[git commit] suppress gcc 8 aliasing warnings

[Denys Vlasenko]

commit: https://git.busybox.net/busybox/commit/?id=136fe9bede247d3273f5e82b5e856fa5c15a922c
branch: https://git.busybox.net/busybox/commit/?id=refs/heads/master

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 at googlemail.com>
---
 include/libbb.h  |  2 ++
 libbb/lineedit.c | 12 +++++++++++-
 libbb/signals.c  | 10 ++++++++++
 shell/ash.c      |  2 +-
 shell/hush.c     |  2 +-
 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! */