Add support for SIGUSR1 and SIGUSR21.1

Signed-off-by: Mattias Andrée <m@maandree.se>

3 files changed, 141 insertions, 21 deletions

diff --git a/TODO b/TODO
index 0cf04b5..f187ecb 100644
--- a/TODO
+++ b/TODO
@@ -1,6 +1,4 @@
 On fade in, query active setting and start from there. (requires libred>=1.1)
 Use bus for changing settings and CRTCs online.
 Add "-t ?" and "-t get" for getting the current temperature. (requires libred>=1.1)
-On SIGUSR1, fade out without terminating
-On SIGUSR2, fade in
 Add PF_UNIX SOCK_DGRAM socket with abstract address @/proc/<pid>/radharc for IPC
diff --git a/radharc.1 b/radharc.1
index df9fb8d..1f4e030 100644
--- a/radharc.1
+++ b/radharc.1
@@ -172,6 +172,22 @@ sent twice, the effect is removed immediately.
 .B SIGHUP
 Terminate the process after any current fade in or fade
 out action, but leaf the effect in place.
+.TP
+.B SIGUSR1
+Gradually fade out the effect but do not terminate the process.
+
+If the fade out time is 0 (default) or if the signal is
+sent twice, the effect is removed immediately.
+.TP
+.B SIGUSR2
+Gradually fade the effect back in (from
+.IR SIGUSR1 ).
+
+If the fade in time is 0 (default) or if the signal is
+sent twice, the effect is restored immediately.
+
+If sent during the initial fade in, the fade in is cancelled
+and the full effect is immediately applied
 
 .SH SEE ALSO
 .BR coopgammad (1),
diff --git a/radharc.c b/radharc.c
index 12f5ce8..c651b8f 100644
--- a/radharc.c
+++ b/radharc.c
@@ -112,6 +112,28 @@ static volatile sig_atomic_t sigint_received = 0;
  */
 static volatile sig_atomic_t sighup_received = 0;
 
+/**
+ * If 0, SIGUSR1 has not been received,
+ * if 1, SIGUSR1 has been received once as the effect
+ *       should be faded out and removed, but the
+ *       the process shall not be terminated
+ * if 2, SIGUSR1 has been received at least twice and
+ *       the effect be removed immediately, but the
+ *       the process shall not be terminated
+ */
+static volatile sig_atomic_t sigusr1_received = 0;
+
+/**
+ * If 0, SIGUSR2 has not been received,
+ * if 1, SIGUSR2 has been received once as the effect
+ *       should be faded back in (from SIGUSR1), or
+ *       if during initial fade-in, the fade-in should
+ *       be skipped over
+ * if 2, SIGUSR2 has been received at least twice and
+ *       the effect be immediately restored
+ */
+static volatile sig_atomic_t sigusr2_received = 0;
+
 
 /**
  * Print usage information and exit
@@ -380,6 +402,30 @@ sighup_handler(int sig)
 
 
 /**
+ * Called when SIGUSR1 is received
+ * 
+ * @param  sig  Always `SIGUSR1`
+ */
+static void
+sigusr1_handler(int sig)
+{
+	sigusr1_received = sigusr1_received ? 2 : 1;
+}
+
+
+/**
+ * Called when SIGUSR2 is received
+ * 
+ * @param  sig  Always `SIGUSR2`
+ */
+static void
+sigusr2_handler(int sig)
+{
+	sigusr2_received = sigusr2_received ? 2 : 1;
+}
+
+
+/**
  * The main function for the program-specific code
  * 
  * @return  0: Success
@@ -400,12 +446,21 @@ start(void)
 	struct sigaction sa;
 	struct timespec sleep_timeout;
 	const char *side;
+	size_t fade_cs;
+	double cs;
+	sigset_t empty_sigset;
+
+	sigemptyset(&empty_sigset);
 
 	memset(&sa, 0, sizeof(sa));
 	sa.sa_handler = &sigint_handler;
 	sigaction(SIGINT, &sa, NULL);
 	sa.sa_handler = &sighup_handler;
 	sigaction(SIGHUP, &sa, NULL);
+	sa.sa_handler = &sigusr1_handler;
+	sigaction(SIGUSR1, &sa, NULL);
+	sa.sa_handler = &sigusr2_handler;
+	sigaction(SIGUSR2, &sa, NULL);
 
 	if (xflag)
 		for (i = 0; i < filters_n; i++)
@@ -427,8 +482,10 @@ start(void)
 	if ((r = make_slaves()) < 0)
 		return r;
 
+
+fade_in:
 	if (!fade_in_cs)
-		goto no_fade_in;
+		goto faded_in;
 
 	tfd = timerfd_create(CLOCK_MONOTONIC, 0);
 	if (tfd < 0)
@@ -436,17 +493,26 @@ start(void)
 	if (timerfd_settime(tfd, 0, &(struct itimerspec){{0, 10000000L}, {0, 10000000L}}, NULL))
 		return -1;
 
-	for (i = 0; i < (size_t)fade_in_cs;) {
+	fade_cs = (size_t)fade_in_cs;
+fade_in_have_timer:
+	for (i = 0; i < fade_cs;) {
 		if (sigint_received) {
-			double cs = (double)i / fade_in_cs * fade_out_cs + 0.5;
-			fade_out_cs = (unsigned long int)cs;
+			goto reverse_fade_in;
+		} else if (sigusr2_received) {
+			sigusr2_received = 0;
+			goto skip_fade_in;
+		} else if (sigusr1_received) {
+			sigusr1_received -= 1;
+		reverse_fade_in:
+			cs = (double)i / fade_cs * fade_out_cs + 0.5;
+			fade_cs = (unsigned long int)cs;
 			goto fade_out_have_timer;
 		}
 
 		if (i % 600 == 0)
 			if ((r = get_temperature(&target_temperature)) < 0)
 				return r;
-		current_temperature = (long int)(6500 - (6500 - target_temperature) * i / fade_in_cs);
+		current_temperature = (long int)(6500 - (6500 - target_temperature) * i / fade_cs);
 		if (libred_get_colour(current_temperature, &red, &green, &blue))
 			return -1;
 		if ((r = set_ramps(red, green, blue)) < 0)
@@ -457,23 +523,29 @@ start(void)
 				continue;
 			return -1;
 		}
-		if (overrun > fade_in_cs - i)
-			overrun = fade_in_cs - i;
+		if (overrun > fade_cs - i)
+			overrun = fade_cs - i;
 		i += overrun;
 	}
 
+skip_fade_in:
 	close(tfd);
 
-no_fade_in:
+
+faded_in:
 	for (;;) {
-		if (sigint_received)
+		if (sigint_received) {
 			goto fade_out;
-
-		if (sighup_received) {
+		} else if (sighup_received) {
 			for (i = 0; i < filters_n; i++)
 				crtc_updates[i].filter.lifespan = LIBCOOPGAMMA_UNTIL_REMOVAL;
 			return set_ramps(red, green, blue);
 		}
+		sigusr2_received = 0;
+		if (sigusr1_received) {
+			sigusr1_received -= 1;
+			goto fade_out;
+		}
 
 		if ((r = get_temperature(&target_temperature)) < 0)
 			return r;
@@ -490,7 +562,7 @@ no_fade_in:
 		sleep_timeout.tv_nsec = 0;
 		while ((errno = clock_nanosleep(CLOCK_BOOTTIME, 0, &sleep_timeout, &sleep_timeout))) {
 			if (errno == EINTR) {
-				if (sigint_received || sighup_received)
+				if (sigint_received || sighup_received || sigusr1_received || sigusr2_received)
 					break;
 				continue;
 			}
@@ -498,20 +570,33 @@ no_fade_in:
 		}
 	}
 
+
 fade_out:
+	if (!fade_out_cs)
+		goto faded_out;
+
 	tfd = timerfd_create(CLOCK_MONOTONIC, 0);
 	if (tfd < 0)
 		goto fade_out_fail;
 	if (timerfd_settime(tfd, 0, &(struct itimerspec){{0, 10000000L}, {0, 10000000L}}, NULL))
 		goto fade_out_fail;
 
+	fade_cs = (size_t)fade_out_cs;
 fade_out_have_timer:
 	original_temperature = current_temperature;
-	for (i = 0; i < (size_t)fade_out_cs;) {
-		if (sigint_received > 1)
-			break;
+	for (i = 0; i < fade_cs;) {
+		if (sigint_received > 1 || sigusr1_received) {
+			goto skip_fade_out;
+		} else if (!sigint_received && !sighup_received) {
+			if (sigusr2_received) {
+				sigusr2_received -= 1;
+				cs = (double)i / fade_cs * fade_in_cs + 0.5;
+				fade_cs = (unsigned long int)cs;
+				goto fade_in_have_timer;
+			}
+		}
 
-		current_temperature = original_temperature + (double)(6500 - original_temperature) * i / fade_out_cs;
+		current_temperature = original_temperature + (double)(6500 - original_temperature) * i / fade_cs;
 		if (libred_get_colour(current_temperature, &red, &green, &blue))
 			goto fade_out_fail;
 		if ((r = set_ramps(red, green, blue)) < 0)
@@ -522,16 +607,37 @@ fade_out_have_timer:
 				continue;
 			goto fade_out_fail;
 		}
-		if (overrun > fade_in_cs - i)
-			overrun = fade_in_cs - i;
+		if (overrun > fade_cs - i)
+			overrun = fade_cs - i;
 		i += overrun;
 	}
 
+skip_fade_out:
 	close(tfd);
 
+
+faded_out:
 	for (i = 0; i < filters_n; i++)
 		crtc_updates[i].filter.lifespan = LIBCOOPGAMMA_REMOVE;
-	return set_ramps(1, 1, 1);
+	if ((r = set_ramps(red, green, blue)) < 0)
+		return r;
+	for (i = 0; i < filters_n; i++)
+		crtc_updates[i].filter.lifespan = LIBCOOPGAMMA_UNTIL_REMOVAL;
+	for (;;) {
+		sigusr1_received = 0;
+		if (sigint_received || sighup_received) {
+			for (i = 0; i < filters_n; i++)
+				crtc_updates[i].filter.lifespan = LIBCOOPGAMMA_REMOVE;
+			return set_ramps(1, 1, 1);
+		} else if (sigusr2_received) {
+			sigusr2_received -= 1;
+			goto fade_in;
+		}
+
+		if (sigsuspend(&empty_sigset) && errno == EFAULT)
+			abort();
+	}
+
 
 fade_out_fail_use_r:
 	switch (r) {