TRACEPOINT_EVENT API
[lttng-ust.git] / include / ust / lttng-tracepoint-event.h
diff --git a/include/ust/lttng-tracepoint-event.h b/include/ust/lttng-tracepoint-event.h
new file mode 100644 (file)
index 0000000..10b2d23
--- /dev/null
@@ -0,0 +1,440 @@
+/*
+ * Copyright (C) 2009     Steven Rostedt <srostedt@redhat.com>
+ * Copyright (C) 2011     Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation;
+ * version 2.1 of the License.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
+ */
+
+#include <stdio.h>
+#include <ust/lttng-events.h>
+
+/*
+ * Macro declarations used for all stages.
+ */
+
+#undef ctf_integer
+#define ctf_integer(_type, _item, _src)                                \
+       ctf_integer_ext(_type, _item, _src, BYTE_ORDER, 10)
+
+#undef ctf_integer_hex
+#define ctf_integer_hex(_type, _item, _src)                    \
+       ctf_integer_ext(_type, _item, _src, BYTE_ORDER, 16)
+
+#undef ctf_integer_network
+#define ctf_integer_network(_type, _item, _src)                        \
+       ctf_integer_ext(_type, _item, _src, BIG_ENDIAN, 10)
+
+#undef ctf_integer_network_hex
+#define ctf_integer_network_hex(_type, _item, _src)            \
+       ctf_integer_ext(_type, _item, _src, BIG_ENDIAN, 16)
+
+#undef ctf_array
+#define ctf_array(_type, _item, _src, _length)                 \
+       ctf_array_encoded(_type, _item, _src, _length, none)
+
+#undef ctf_array_text
+#define ctf_array_text(_type, _item, _src, _length)            \
+       ctf_array_encoded(_type, _item, _src, _length, UTF8)
+
+#undef ctf_sequence
+#define ctf_sequence(_type, _item, _src, _length_type, _src_length)    \
+       ctf_sequence_encoded(_type, _item, _src,                        \
+                       _length_type, _src_length, none)
+
+#undef ctf_sequence_text
+#define ctf_sequence_text(_type, _item, _src, _length_type, _src_length) \
+       ctf_sequence_encoded(_type, _item, _src,                         \
+                       _length_type, _src_length, UTF8)
+
+/* ctf_string is redefined at each step */
+
+/*
+ * TRACEPOINT_EVENT_CLASS can be used to add a generic function handlers
+ * for events. That is, if all events have the same parameters and just
+ * have distinct trace points.  Each tracepoint can be defined with
+ * TRACEPOINT_EVENT_INSTANCE and that will map the
+ * TRACEPOINT_EVENT_CLASS to the tracepoint.
+ *
+ * TRACEPOINT_EVENT is a one to one mapping between tracepoint and
+ * template.
+ */
+
+#undef TRACEPOINT_EVENT
+#define TRACEPOINT_EVENT(name, proto, args, fields)    \
+       TRACEPOINT_EVENT_CLASS(name,                    \
+                            TP_PARAMS(proto),          \
+                            TP_PARAMS(args),           \
+                            TP_PARAMS(fields))         \
+       TRACEPOINT_EVENT_INSTANCE(name, name, TP_PARAMS(proto), TP_PARAMS(args))
+
+/*
+ * Stage 1 of the trace events.
+ *
+ * Create event field type metadata section.
+ * Each event produce an array of fields.
+ */
+
+/* Reset all macros within TRACE_EVENT */
+#include "lttng-tracepoint-events-reset.h"
+
+/* Named field types must be defined in lttng-types.h */
+
+#undef ctf_integer_ext
+#define ctf_integer_ext(_type, _item, _src, _byte_order, _base)        \
+       {                                                       \
+         .name = #_item,                                       \
+         .type = __type_integer(_type, _byte_order, _base, none),\
+       },
+
+#undef ctf_array_encoded
+#define ctf_array_encoded(_type, _item, _src, _length, _encoding) \
+       {                                                       \
+         .name = #_item,                                       \
+         .type =                                               \
+               {                                               \
+                 .atype = atype_array,                         \
+                 .u.array =                                    \
+                       {                                       \
+                           .length = _length,                  \
+                           .elem_type = __type_integer(_type, BYTE_ORDER, 10, _encoding), \
+                       },                                      \
+               },                                              \
+       },
+
+#undef ctf_sequence_encoded
+#define ctf_sequence_encoded(_type, _item, _src,       \
+                       _length_type, _src_length, _encoding)   \
+       {                                                       \
+         .name = #_item,                                       \
+         .type =                                               \
+               {                                               \
+                 .atype = atype_sequence,                      \
+                 .u.sequence =                                 \
+                       {                                       \
+                           .length_type = __type_integer(_length_type, BYTE_ORDER, 10, none), \
+                           .elem_type = __type_integer(_type, BYTE_ORDER, 10, _encoding), \
+                       },                                      \
+               },                                              \
+       },
+
+#undef ctf_string
+#define ctf_string(_item, _src)                                        \
+       {                                                       \
+         .name = #_item,                                       \
+         .type =                                               \
+               {                                               \
+                 .atype = atype_string,                        \
+                 .u.basic.string.encoding = lttng_encode_UTF8, \
+               },                                              \
+       },
+
+#undef TP_FIELDS
+#define TP_FIELDS(args...) args        /* Only one used in this phase */
+
+#undef TRACEPOINT_EVENT_CLASS
+#define TRACEPOINT_EVENT_CLASS(_name, _proto, _args, _fields)               \
+       static const struct lttng_event_field __event_fields___##_name[] = { \
+               _fields                                                      \
+       };
+
+#include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
+
+/*
+ * Stage 2 of the trace events.
+ *
+ * Create probe callback prototypes.
+ */
+
+/* Reset all macros within TRACE_EVENT */
+#include "lttng-tracepoint-events-reset.h"
+
+#undef TP_PROTO
+#define TP_PROTO(args...) args
+
+#undef TRACEPOINT_EVENT_CLASS
+#define TRACEPOINT_EVENT_CLASS(_name, _proto, _args, _fields)  \
+static void __event_probe__##_name(void *__data, _proto);
+
+#include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
+
+/*
+ * Stage 3 of the trace events.
+ *
+ * Create an array of events.
+ */
+
+/* Named field types must be defined in lttng-types.h */
+
+/* Reset all macros within TRACE_EVENT */
+#include "lttng-tracepoint-events-reset.h"
+
+#undef TRACEPOINT_EVENT_INSTANCE
+#define TRACEPOINT_EVENT_INSTANCE(_template, _name, _proto, _args)            \
+               {                                                              \
+                       .fields = __event_fields___##_template,                \
+                       .name = #_name,                                        \
+                       .probe_callback = (void *) &__event_probe__##_template,\
+                       .nr_fields = ARRAY_SIZE(__event_fields___##_template), \
+               },
+
+#define TP_ID1(_token, _system)        _token##_system
+#define TP_ID(_token, _system) TP_ID1(_token, _system)
+
+static const struct lttng_event_desc TP_ID(__event_desc___, TRACE_SYSTEM)[] = {
+#include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
+};
+
+#undef TP_ID1
+#undef TP_ID
+
+
+/*
+ * Stage 4 of the trace events.
+ *
+ * Create a toplevel descriptor for the whole probe.
+ */
+
+#define TP_ID1(_token, _system)        _token##_system
+#define TP_ID(_token, _system) TP_ID1(_token, _system)
+
+/* non-const because list head will be modified when registered. */
+static struct lttng_probe_desc TP_ID(__probe_desc___, TRACE_SYSTEM) = {
+       .event_desc = TP_ID(__event_desc___, TRACE_SYSTEM),
+       .nr_events = ARRAY_SIZE(TP_ID(__event_desc___, TRACE_SYSTEM)),
+};
+
+#undef TP_ID1
+#undef TP_ID
+
+/*
+ * Stage 5 of the trace events.
+ *
+ * Create static inline function that calculates event size.
+ */
+
+/* Reset all macros within TRACE_EVENT */
+#include "lttng-tracepoint-events-reset.h"
+
+/* Named field types must be defined in lttng-types.h */
+
+#undef ctf_integer_ext
+#define ctf_integer_ext(_type, _item, _src, _byte_order, _base)                       \
+       __event_len += lib_ring_buffer_align(__event_len, ltt_alignof(_type)); \
+       __event_len += sizeof(_type);
+
+#undef ctf_array_encoded
+#define ctf_array_encoded(_type, _item, _src, _length)                        \
+       __event_len += lib_ring_buffer_align(__event_len, ltt_alignof(_type)); \
+       __event_len += sizeof(_type) * (_length);
+
+#undef ctf_sequence_encoded
+#define ctf_sequence_encoded(_type, _item, _src, _length_type, \
+                       _src_length, _encoding)                 \
+       __event_len += lib_ring_buffer_align(__event_len, ltt_alignof(_length_type));   \
+       __event_len += sizeof(_length_type);                                   \
+       __event_len += lib_ring_buffer_align(__event_len, ltt_alignof(_type)); \
+       __dynamic_len[__dynamic_len_idx] = (_length);                          \
+       __event_len += sizeof(_type) * __dynamic_len[__dynamic_len_idx];       \
+       __dynamic_len_idx++;
+
+#undef ctf_string
+#define ctf_string(_item, _src)                                                       \
+       __event_len += __dynamic_len[__dynamic_len_idx++] = strlen(_src) + 1;
+
+#undef TP_PROTO
+#define TP_PROTO(args...) args
+
+#undef TP_FIELDS
+#define TP_FIELDS(args...) args
+
+#undef TRACEPOINT_EVENT_CLASS
+#define TRACEPOINT_EVENT_CLASS(_name, _proto, _args, _fields)                \
+static inline size_t __event_get_size__##_name(size_t *__dynamic_len, _proto) \
+{                                                                            \
+       size_t __event_len = 0;                                               \
+       unsigned int __dynamic_len_idx = 0;                                   \
+                                                                             \
+       if (0)                                                                \
+               (void) __dynamic_len_idx;       /* don't warn if unused */    \
+       _fields                                                               \
+       return __event_len;                                                   \
+}
+
+#include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
+
+/*
+ * Stage 6 of the trace events.
+ *
+ * Create static inline function that calculates event payload alignment.
+ */
+
+/* Reset all macros within TRACE_EVENT */
+#include "lttng-tracepoint-events-reset.h"
+
+/* Named field types must be defined in lttng-types.h */
+
+#undef ctf_integer_ext
+#define ctf_integer_ext(_type, _item, _src, _byte_order, _base)                       \
+       __event_align = max_t(size_t, __event_align, ltt_alignof(_type));
+
+#undef ctf_array_encoded
+#define ctf_array_encoded(_type, _item, _src, _length)                        \
+       __event_align = max_t(size_t, __event_align, ltt_alignof(_type));
+
+#undef ctf_sequence_encoded
+#define ctf_sequence_encoded(_type, _item, _src, _length_type, \
+                       _src_length, _encoding)                 \
+       __event_align = max_t(size_t, __event_align, ltt_alignof(_length_type));          \
+       __event_align = max_t(size_t, __event_align, ltt_alignof(_type));
+
+#undef ctf_string
+#define ctf_string(_item, _src)
+
+#undef TP_PROTO
+#define TP_PROTO(args...) args
+
+#undef TP_FIELDS
+#define TP_FIELDS(args...) args
+
+#undef TRACEPOINT_EVENT_CLASS
+#define TRACEPOINT_EVENT_CLASS(_name, _proto, _args, _fields)                \
+static inline size_t __event_get_align__##_name(_proto)                              \
+{                                                                            \
+       size_t __event_align = 1;                                             \
+       _fields                                                               \
+       return __event_align;                                                 \
+}
+
+#include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
+
+
+/*
+ * Stage 7 of the trace events.
+ *
+ * Create the probe function : call even size calculation and write event data
+ * into the buffer.
+ *
+ * We use both the field and assignment macros to write the fields in the order
+ * defined in the field declaration. The field declarations control the
+ * execution order, jumping to the appropriate assignment block.
+ */
+
+/* Reset all macros within TRACE_EVENT */
+#include "lttng-tracepoint-events-reset.h"
+
+#undef ctf_integer_ext
+#define ctf_integer_ext(_type, _item, _src, _byte_order, _base)                \
+       {                                                               \
+               _type __tmp = (_src);                                   \
+               lib_ring_buffer_align_ctx(&ctx, ltt_alignof(__tmp));    \
+               __chan->ops->event_write(&ctx, &__tmp, sizeof(__tmp));  \
+       }
+
+#undef ctf_array_encoded
+#define ctf_array_encoded(_type, _item, _src, _length)                 \
+       lib_ring_buffer_align_ctx(&ctx, ltt_alignof(_type));            \
+       __chan->ops->event_write(&ctx, _src, _length);
+
+#undef ctf_sequence_encoded
+#define ctf_sequence_encoded(_type, _item, _src, _length_type,         \
+                       _src_length, _encoding)                 \
+       {                                                               \
+               _length_type __tmpl = __dynamic_len[__dynamic_len_idx]; \
+               lib_ring_buffer_align_ctx(&ctx, ltt_alignof(_length_type));    \
+               __chan->ops->event_write(&ctx, &__tmpl, sizeof(_length_type)); \
+       }                                                               \
+       lib_ring_buffer_align_ctx(&ctx, ltt_alignof(_type));            \
+       __chan->ops->event_write(&ctx, _src,                            \
+               sizeof(_type) * __get_sequence_len(dest));
+
+#undef ctf_string
+#define ctf_string(_item, _src)                                                \
+       tp_memcpy(dest, _src, __get_sequence_len(dest))
+
+/* Beware: this get len actually consumes the len value */
+#undef __get_sequence_len
+#define __get_sequence_len(field)      __dynamic_len[__dynamic_len_idx++]
+
+#undef TP_PROTO
+#define TP_PROTO(args...) args
+
+#undef TP_ARGS
+#define TP_ARGS(args...) args
+
+#undef TP_FIELDS
+#define TP_FIELDS(args...) args
+
+#undef TRACEPOINT_EVENT_CLASS
+#define TRACEPOINT_EVENT_CLASS(_name, _proto, _args, _fields)                \
+static void __event_probe__##_name(void *__data, _proto)                     \
+{                                                                            \
+       struct ltt_event *__event = __data;                                   \
+       struct ltt_channel *__chan = __event->chan;                           \
+       struct lib_ring_buffer_ctx ctx;                                       \
+       size_t __event_len, __event_align;                                    \
+       size_t __dynamic_len_idx = 0;                                         \
+       size_t __dynamic_len[ARRAY_SIZE(__event_fields___##_name)];           \
+       int __ret;                                                            \
+                                                                             \
+       if (0)                                                                \
+               (void) __dynamic_len_idx;       /* don't warn if unused */    \
+       if (unlikely(!ACCESS_ONCE(__chan->session->active)))                  \
+               return;                                                       \
+       if (unlikely(!ACCESS_ONCE(__chan->enabled)))                          \
+               return;                                                       \
+       if (unlikely(!ACCESS_ONCE(__event->enabled)))                         \
+               return;                                                       \
+       __event_len = __event_get_size__##_name(__dynamic_len, _args);        \
+       __event_align = __event_get_align__##_name(_args);                    \
+       lib_ring_buffer_ctx_init(&ctx, __chan->chan, __event, __event_len,    \
+                                __event_align, -1);                          \
+       __ret = __chan->ops->event_reserve(&ctx, __event->id);                \
+       if (__ret < 0)                                                        \
+               return;                                                       \
+       _fields                                                               \
+       __chan->ops->event_commit(&ctx);                                      \
+}
+
+#include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
+
+/*
+ * Stage 8 of the trace events.
+ *
+ * Register/unregister probes at module load/unload.
+ */
+
+/* Reset all macros within TRACE_EVENT */
+#include "lttng-tracepoint-events-reset.h"
+
+#define TP_ID1(_token, _system)        _token##_system
+#define TP_ID(_token, _system) TP_ID1(_token, _system)
+
+static void __attribute__((constructor))
+TP_ID(__lttng_events_init__, TRACE_SYSTEM)(void)
+{
+       int ret;
+
+       ret = ltt_probe_register(&TP_ID(__probe_desc___, TRACE_SYSTEM));
+       assert(!ret);
+}
+
+static void __attribute__((destructor))
+TP_ID(__lttng_events_exit__, TRACE_SYSTEM)(void)
+{
+       ltt_probe_unregister(&TP_ID(__probe_desc___, TRACE_SYSTEM));
+}
+
+#undef TP_ID1
+#undef TP_ID
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