From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Thu, 10 Feb 2022 20:40:25 +0000 (-0500)
Subject: kretprobes: implement counter support
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=327374656ed97ef208450d0ae51ec475e4efeb49;p=lttng-modules.git

kretprobes: implement counter support

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I8e64712455b2812305250a45311b5b023281a1fe
---

diff --git a/src/probes/lttng-kretprobes.c b/src/probes/lttng-kretprobes.c
index 410e5f79..55866a82 100644
--- a/src/probes/lttng-kretprobes.c
+++ b/src/probes/lttng-kretprobes.c
@@ -17,6 +17,7 @@
 #include <wrapper/compiler_attributes.h>
 #include <wrapper/vmalloc.h>
 #include <wrapper/irqflags.h>
+#include <wrapper/rcu.h>
 #include <lttng/tracer.h>
 #include <blacklist/kprobes.h>
 
@@ -40,6 +41,7 @@ int _lttng_kretprobes_handler(struct kretprobe_instance *krpi,
 	struct lttng_krp *lttng_krp =
 		container_of(lttng_get_kretprobe(krpi), struct lttng_krp, krp);
 	struct lttng_kernel_event_common *event = lttng_krp->event[type];
+	struct lttng_kernel_channel_common *chan_common;
 	struct lttng_kernel_probe_ctx lttng_probe_ctx = {
 		.event = event,
 		.interruptible = !lttng_regs_irqs_disabled(regs),
@@ -49,27 +51,37 @@ int _lttng_kretprobes_handler(struct kretprobe_instance *krpi,
 		unsigned long parent_ip;
 	} payload;
 
-	switch (event->type) {
-	case LTTNG_KERNEL_EVENT_TYPE_RECORDER:
-	{
-		struct lttng_kernel_event_recorder *event_recorder =
-			container_of(event, struct lttng_kernel_event_recorder, parent);
-		struct lttng_kernel_channel_buffer *chan = event_recorder->chan;
-
-		if (unlikely(!LTTNG_READ_ONCE(chan->parent.session->active)))
-			return 0;
-		if (unlikely(!LTTNG_READ_ONCE(chan->parent.enabled)))
-			return 0;
-		break;
-	}
-	case LTTNG_KERNEL_EVENT_TYPE_NOTIFIER:
-		lttng_fallthrough;
-	default:
-		WARN_ON_ONCE(1);
-	}
-
 	if (unlikely(!LTTNG_READ_ONCE(event->enabled)))
-		return 0;
+		goto end;
+
+	chan_common = lttng_kernel_get_chan_common_from_event_common(event);
+	if (chan_common) {
+		struct lttng_kernel_session *session = chan_common->session;
+		struct lttng_kernel_id_tracker_rcu *lf;
+
+		if (unlikely(!LTTNG_READ_ONCE(session->active)))
+			goto end;
+		if (unlikely(!LTTNG_READ_ONCE(chan_common->enabled)))
+			goto end;
+		lf = lttng_rcu_dereference(session->pid_tracker.p);
+		if (lf && likely(!lttng_id_tracker_lookup(lf, current->tgid)))
+			goto end;
+		lf = lttng_rcu_dereference(session->vpid_tracker.p);
+		if (lf && likely(!lttng_id_tracker_lookup(lf, task_tgid_vnr(current))))
+			goto end;
+		lf = lttng_rcu_dereference(session->uid_tracker.p);
+		if (lf && likely(!lttng_id_tracker_lookup(lf, from_kuid_munged(&init_user_ns, current_uid()))))
+			goto end;
+		lf = lttng_rcu_dereference(session->vuid_tracker.p);
+		if (lf && likely(!lttng_id_tracker_lookup(lf, from_kuid_munged(current_user_ns(), current_uid()))))
+			goto end;
+		lf = lttng_rcu_dereference(session->gid_tracker.p);
+		if (lf && likely(!lttng_id_tracker_lookup(lf, from_kgid_munged(&init_user_ns, current_gid()))))
+			goto end;
+		lf = lttng_rcu_dereference(session->vgid_tracker.p);
+		if (lf && likely(!lttng_id_tracker_lookup(lf, from_kgid_munged(current_user_ns(), current_gid()))))
+			goto end;
+	}
 
 	switch (event->type) {
 	case LTTNG_KERNEL_EVENT_TYPE_RECORDER:
@@ -92,11 +104,20 @@ int _lttng_kretprobes_handler(struct kretprobe_instance *krpi,
 		chan->ops->event_commit(&ctx);
 		break;
 	}
+	case LTTNG_KERNEL_EVENT_TYPE_COUNTER:
+	{
+		struct lttng_kernel_event_counter *event_counter =
+			container_of(event, struct lttng_kernel_event_counter, parent);
+
+		(void) event_counter->chan->ops->event_counter_add(event_counter, 1);
+		break;
+	}
 	case LTTNG_KERNEL_EVENT_TYPE_NOTIFIER:
 		lttng_fallthrough;
 	default:
 		WARN_ON_ONCE(1);
 	}
+end:
 	return 0;
 }