From 7c5b4f82fc79bf04d679d4e4427525d63cdd7614 Mon Sep 17 00:00:00 2001
From: Martin Kepplinger <martink@posteo.de>
Date: Tue, 25 Apr 2017 19:03:25 +0200
Subject: [PATCH] plugins: filters: check for read_mt() availability

In case users use raw modules that don't implement ts_read(), we must fail
gracefully.
---
 plugins/debounce.c | 3 +++
 plugins/dejitter.c | 3 +++
 plugins/iir.c      | 3 +++
 plugins/linear.c   | 3 +++
 plugins/median.c   | 3 +++
 plugins/pthres.c   | 3 +++
 plugins/skip.c     | 3 +++
 plugins/variance.c | 3 +++
 8 files changed, 24 insertions(+)

diff --git a/plugins/debounce.c b/plugins/debounce.c
index 41adfb81..b60313a9 100644
--- a/plugins/debounce.c
+++ b/plugins/debounce.c
@@ -131,6 +131,9 @@ static int debounce_read_mt(struct tslib_module_info *info, struct ts_sample_mt
 		p->current_max_slots = max_slots;
 	}
 
+	if (!info->next->ops->read_mt)
+		return -ENOSYS;
+
 	ret = info->next->ops->read_mt(info->next, samp, max_slots, nr_samples);
 	if (ret < 0)
 		return ret;
diff --git a/plugins/dejitter.c b/plugins/dejitter.c
index f2f2f2f8..27dc4d44 100644
--- a/plugins/dejitter.c
+++ b/plugins/dejitter.c
@@ -193,6 +193,9 @@ static int dejitter_read_mt(struct tslib_module_info *info,
 	int ret;
 	int i, j;
 
+	if (!info->next->ops->read_mt)
+		return -ENOSYS;
+
 	ret = info->next->ops->read_mt(info->next, samp, max_slots, nr);
 	if (ret < 0)
 		return ret;
diff --git a/plugins/iir.c b/plugins/iir.c
index 8f375b49..245515a3 100644
--- a/plugins/iir.c
+++ b/plugins/iir.c
@@ -132,6 +132,9 @@ static int iir_read_mt(struct tslib_module_info *info,
 		iir->slots = max_slots;
 	}
 
+	if (!info->next->ops->read_mt)
+		return -ENOSYS;
+
 	ret = info->next->ops->read_mt(info->next, samp, max_slots, nr);
 	if (ret < 0)
 		return ret;
diff --git a/plugins/linear.c b/plugins/linear.c
index 8bd17afb..75872fa7 100644
--- a/plugins/linear.c
+++ b/plugins/linear.c
@@ -94,6 +94,9 @@ static int linear_read_mt(struct tslib_module_info *info,
 	int i;
 	int nr;
 
+	if (!info->next->ops->read_mt)
+		return -ENOSYS;
+
 	ret = info->next->ops->read_mt(info->next, samp, max_slots, nr_samples);
 	if (ret < 0)
 		return ret;
diff --git a/plugins/median.c b/plugins/median.c
index 00b3e1ad..c10d5bcd 100644
--- a/plugins/median.c
+++ b/plugins/median.c
@@ -199,6 +199,9 @@ static int median_read_mt(struct tslib_module_info *inf,
 	int ret;
 	int i, j;
 
+	if (!inf->next->ops->read_mt)
+		return -ENOSYS;
+
 	ret = inf->next->ops->read_mt(inf->next, samp, max_slots, nr);
 	if (ret < 0)
 		return ret;
diff --git a/plugins/pthres.c b/plugins/pthres.c
index 49d3fe49..0b4de487 100644
--- a/plugins/pthres.c
+++ b/plugins/pthres.c
@@ -143,6 +143,9 @@ static int pthres_read_mt(struct tslib_module_info *info,
 		p->current_max_slots = max_slots;
 	}
 
+	if (!info->next->ops->read_mt)
+		return -ENOSYS;
+
 	ret = info->next->ops->read_mt(info->next, samp, max_slots, nr_samples);
 	if (ret < 0)
 		return ret;
diff --git a/plugins/skip.c b/plugins/skip.c
index 56714cbe..c68520fc 100644
--- a/plugins/skip.c
+++ b/plugins/skip.c
@@ -236,6 +236,9 @@ static int skip_read_mt(struct tslib_module_info *info,
 		skip->slots = max_slots;
 	}
 
+	if (!info->next->ops->read_mt)
+		return -ENOSYS;
+
 	ret = info->next->ops->read_mt(info->next, samp, max_slots, nr);
 	if (ret < 0)
 		return ret;
diff --git a/plugins/variance.c b/plugins/variance.c
index e729294a..0154f1dc 100644
--- a/plugins/variance.c
+++ b/plugins/variance.c
@@ -150,6 +150,9 @@ static int variance_read_mt(struct tslib_module_info *info,
 	short pen_down = 1;
 	int ret;
 
+	if (!info->next->ops->read_mt)
+		return -ENOSYS;
+
 	if (var->samp == NULL) {
 		var->samp = calloc(nr, sizeof(struct ts_sample));
 		if (!var->samp)