Detailed system call tracing (TRACE_EVENT() generation for integer support)

[lttng-modules.git] / probes / lttng-kprobes.c

diff --git a/probes/lttng-kprobes.c b/probes/lttng-kprobes.c
index daef3600feefd580bb0db79357d09428f8eb21eb..8e1ae832cd82abb14d0413a1aee5b13cb1cd9fc8 100644 (file)
--- a/probes/lttng-kprobes.c
+++ b/probes/lttng-kprobes.c
@@ -25,11 +25,16 @@ int lttng_kprobes_handler_pre(struct kprobe *p, struct pt_regs *regs)
        int ret;
        unsigned long data = (unsigned long) p->addr;
 
-       if (!ACCESS_ONCE(chan->session->active))
+       if (unlikely(!ACCESS_ONCE(chan->session->active)))
                return 0;
-       lib_ring_buffer_ctx_init(&ctx, chan->chan, NULL, sizeof(data),
+       if (unlikely(!ACCESS_ONCE(chan->enabled)))
+               return 0;
+       if (unlikely(!ACCESS_ONCE(event->enabled)))
+               return 0;
+
+       lib_ring_buffer_ctx_init(&ctx, chan->chan, event, sizeof(data),
                                 ltt_alignof(data), -1);
-       ret = chan->ops->event_reserve(&ctx);
+       ret = chan->ops->event_reserve(&ctx, event->id);
        if (ret < 0)
                return 0;
        lib_ring_buffer_align_ctx(&ctx, ltt_alignof(data));
@@ -59,18 +64,25 @@ int lttng_create_kprobe_event(const char *name, struct ltt_event *event)
        desc->nr_fields = 1;
        desc->fields = field =
                kzalloc(1 * sizeof(struct lttng_event_field), GFP_KERNEL);
+       if (!field) {
+               ret = -ENOMEM;
+               goto error_field;
+       }
        field->name = "ip";
        field->type.atype = atype_integer;
-       field->type.u.basic.integer.size = sizeof(unsigned long);
-       field->type.u.basic.integer.alignment = ltt_alignof(unsigned long);
-       field->type.u.basic.integer.signedness = 0;
+       field->type.u.basic.integer.size = sizeof(unsigned long) * CHAR_BIT;
+       field->type.u.basic.integer.alignment = ltt_alignof(unsigned long) * CHAR_BIT;
+       field->type.u.basic.integer.signedness = is_signed_type(unsigned long);
        field->type.u.basic.integer.reverse_byte_order = 0;
        field->type.u.basic.integer.base = 16;
        field->type.u.basic.integer.encoding = lttng_encode_none;
+       desc->owner = THIS_MODULE;
        event->desc = desc;
 
        return 0;
 
+error_field:
+       kfree(desc->name);
 error_str:
        kfree(desc);
        return ret;
@@ -84,22 +96,28 @@ int lttng_kprobes_register(const char *name,
 {
        int ret;
 
+       /* Kprobes expects a NULL symbol name if unused */
+       if (symbol_name[0] == '\0')
+               symbol_name = NULL;
+
        ret = lttng_create_kprobe_event(name, event);
        if (ret)
                goto error;
        memset(&event->u.kprobe.kp, 0, sizeof(event->u.kprobe.kp));
        event->u.kprobe.kp.pre_handler = lttng_kprobes_handler_pre;
-       event->u.kprobe.symbol_name =
-               kzalloc(LTTNG_SYM_NAME_LEN * sizeof(char),
-                       GFP_KERNEL);
-       if (!event->u.kprobe.symbol_name) {
-               ret = -ENOMEM;
-               goto name_error;
+       if (symbol_name) {
+               event->u.kprobe.symbol_name =
+                       kzalloc(LTTNG_SYM_NAME_LEN * sizeof(char),
+                               GFP_KERNEL);
+               if (!event->u.kprobe.symbol_name) {
+                       ret = -ENOMEM;
+                       goto name_error;
+               }
+               memcpy(event->u.kprobe.symbol_name, symbol_name,
+                      LTTNG_SYM_NAME_LEN * sizeof(char));
+               event->u.kprobe.kp.symbol_name =
+                       event->u.kprobe.symbol_name;
        }
-       memcpy(event->u.kprobe.symbol_name, symbol_name,
-              LTTNG_SYM_NAME_LEN * sizeof(char));
-       event->u.kprobe.kp.symbol_name =
-               event->u.kprobe.symbol_name;
        event->u.kprobe.kp.offset = offset;
        event->u.kprobe.kp.addr = (void *) addr;
 
@@ -118,6 +136,7 @@ int lttng_kprobes_register(const char *name,
 register_error:
        kfree(event->u.kprobe.symbol_name);
 name_error:
+       kfree(event->desc->fields);
        kfree(event->desc->name);
        kfree(event->desc);
 error:
@@ -128,11 +147,17 @@ EXPORT_SYMBOL_GPL(lttng_kprobes_register);
 void lttng_kprobes_unregister(struct ltt_event *event)
 {
        unregister_kprobe(&event->u.kprobe.kp);
+}
+EXPORT_SYMBOL_GPL(lttng_kprobes_unregister);
+
+void lttng_kprobes_destroy_private(struct ltt_event *event)
+{
        kfree(event->u.kprobe.symbol_name);
+       kfree(event->desc->fields);
        kfree(event->desc->name);
        kfree(event->desc);
 }
-EXPORT_SYMBOL_GPL(lttng_kprobes_unregister);
+EXPORT_SYMBOL_GPL(lttng_kprobes_destroy_private);
 
 MODULE_LICENSE("GPL and additional rights");
 MODULE_AUTHOR("Mathieu Desnoyers");