kprobe: implement counter support

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I8741ab89b03089ec34f17965749f84ddc23a2601

diff --git a/src/probes/lttng-kprobes.c b/src/probes/lttng-kprobes.c
index 20d7877314873bb70d7bef37745befe5d3d2fd76..bb6decc084181a670c698236ab8cf2b21bdbb822 100644 (file)
--- a/src/probes/lttng-kprobes.c
+++ b/src/probes/lttng-kprobes.c
@@ -15,6 +15,7 @@
 #include <ringbuffer/frontend_types.h>
 #include <wrapper/vmalloc.h>
 #include <wrapper/irqflags.h>
+#include <wrapper/rcu.h>
 #include <lttng/tracer.h>
 #include <blacklist/kprobes.h>
 
@@ -24,34 +25,44 @@ int lttng_kprobes_event_handler_pre(struct kprobe *p, struct pt_regs *regs)
        struct lttng_kernel_event_common_private *event_priv =
                container_of(p, struct lttng_kernel_event_common_private, u.kprobe.kp);
        struct lttng_kernel_event_common *event = event_priv->pub;
+       struct lttng_kernel_channel_common *chan_common;
        struct lttng_kernel_probe_ctx lttng_probe_ctx = {
                .event = event,
                .interruptible = !lttng_regs_irqs_disabled(regs),
        };
        unsigned long data = (unsigned long) p->addr;
 
-       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:
-               break;
-       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:
        {
@@ -80,9 +91,18 @@ int lttng_kprobes_event_handler_pre(struct kprobe *p, struct pt_regs *regs)
                event_notifier->notification_send(event_notifier, NULL, NULL, &notif_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;
+       }
        default:
                WARN_ON_ONCE(1);
        }
+end:
        return 0;
 }