+/*
+ * lttng-events.c
+ *
+ * Copyright 2010-2011 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * Holds LTTng per-session event registry.
+ *
+ * Dual LGPL v2.1/GPL v2 license.
+ */
+
+#include <linux/module.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/jiffies.h>
+#include "wrapper/uuid.h"
+#include "wrapper/vmalloc.h" /* for wrapper_vmalloc_sync_all() */
+#include "lttng-events.h"
+#include "lttng-tracer.h"
+
+static LIST_HEAD(sessions);
+static LIST_HEAD(lttng_transport_list);
+static DEFINE_MUTEX(sessions_mutex);
+static struct kmem_cache *event_cache;
+
+static void _lttng_event_destroy(struct lttng_event *event);
+static void _lttng_channel_destroy(struct lttng_channel *chan);
+static int _lttng_event_unregister(struct lttng_event *event);
+static
+int _lttng_event_metadata_statedump(struct lttng_session *session,
+ struct lttng_channel *chan,
+ struct lttng_event *event);
+static
+int _lttng_session_metadata_statedump(struct lttng_session *session);
+
+void synchronize_trace(void)
+{
+ synchronize_sched();
+#ifdef CONFIG_PREEMPT_RT
+ synchronize_rcu();
+#endif
+}
+
+struct lttng_session *lttng_session_create(void)
+{
+ struct lttng_session *session;
+
+ mutex_lock(&sessions_mutex);
+ session = kzalloc(sizeof(struct lttng_session), GFP_KERNEL);
+ if (!session)
+ return NULL;
+ INIT_LIST_HEAD(&session->chan);
+ INIT_LIST_HEAD(&session->events);
+ uuid_le_gen(&session->uuid);
+ list_add(&session->list, &sessions);
+ mutex_unlock(&sessions_mutex);
+ return session;
+}
+
+void lttng_session_destroy(struct lttng_session *session)
+{
+ struct lttng_channel *chan, *tmpchan;
+ struct lttng_event *event, *tmpevent;
+ int ret;
+
+ mutex_lock(&sessions_mutex);
+ ACCESS_ONCE(session->active) = 0;
+ list_for_each_entry(chan, &session->chan, list) {
+ ret = lttng_syscalls_unregister(chan);
+ WARN_ON(ret);
+ }
+ list_for_each_entry(event, &session->events, list) {
+ ret = _lttng_event_unregister(event);
+ WARN_ON(ret);
+ }
+ synchronize_trace(); /* Wait for in-flight events to complete */
+ list_for_each_entry_safe(event, tmpevent, &session->events, list)
+ _lttng_event_destroy(event);
+ list_for_each_entry_safe(chan, tmpchan, &session->chan, list)
+ _lttng_channel_destroy(chan);
+ list_del(&session->list);
+ mutex_unlock(&sessions_mutex);
+ kfree(session);
+}
+
+int lttng_session_enable(struct lttng_session *session)
+{
+ int ret = 0;
+ struct lttng_channel *chan;
+
+ mutex_lock(&sessions_mutex);
+ if (session->active) {
+ ret = -EBUSY;
+ goto end;
+ }
+
+ /*
+ * Snapshot the number of events per channel to know the type of header
+ * we need to use.
+ */
+ list_for_each_entry(chan, &session->chan, list) {
+ if (chan->header_type)
+ continue; /* don't change it if session stop/restart */
+ if (chan->free_event_id < 31)
+ chan->header_type = 1; /* compact */
+ else
+ chan->header_type = 2; /* large */
+ }
+
+ ACCESS_ONCE(session->active) = 1;
+ ACCESS_ONCE(session->been_active) = 1;
+ ret = _lttng_session_metadata_statedump(session);
+ if (ret)
+ ACCESS_ONCE(session->active) = 0;
+end:
+ mutex_unlock(&sessions_mutex);
+ return ret;
+}
+
+int lttng_session_disable(struct lttng_session *session)
+{
+ int ret = 0;
+
+ mutex_lock(&sessions_mutex);
+ if (!session->active) {
+ ret = -EBUSY;
+ goto end;
+ }
+ ACCESS_ONCE(session->active) = 0;
+end:
+ mutex_unlock(&sessions_mutex);
+ return ret;
+}
+
+int lttng_channel_enable(struct lttng_channel *channel)
+{
+ int old;
+
+ if (channel == channel->session->metadata)
+ return -EPERM;
+ old = xchg(&channel->enabled, 1);
+ if (old)
+ return -EEXIST;
+ return 0;
+}
+
+int lttng_channel_disable(struct lttng_channel *channel)
+{
+ int old;
+
+ if (channel == channel->session->metadata)
+ return -EPERM;
+ old = xchg(&channel->enabled, 0);
+ if (!old)
+ return -EEXIST;
+ return 0;
+}
+
+int lttng_event_enable(struct lttng_event *event)
+{
+ int old;
+
+ if (event->chan == event->chan->session->metadata)
+ return -EPERM;
+ old = xchg(&event->enabled, 1);
+ if (old)
+ return -EEXIST;
+ return 0;
+}
+
+int lttng_event_disable(struct lttng_event *event)
+{
+ int old;
+
+ if (event->chan == event->chan->session->metadata)
+ return -EPERM;
+ old = xchg(&event->enabled, 0);
+ if (!old)
+ return -EEXIST;
+ return 0;
+}
+
+static struct lttng_transport *lttng_transport_find(const char *name)
+{
+ struct lttng_transport *transport;
+
+ list_for_each_entry(transport, <tng_transport_list, node) {
+ if (!strcmp(transport->name, name))
+ return transport;
+ }
+ return NULL;
+}
+
+struct lttng_channel *lttng_channel_create(struct lttng_session *session,
+ const char *transport_name,
+ void *buf_addr,
+ size_t subbuf_size, size_t num_subbuf,
+ unsigned int switch_timer_interval,
+ unsigned int read_timer_interval)
+{
+ struct lttng_channel *chan;
+ struct lttng_transport *transport = NULL;
+
+ mutex_lock(&sessions_mutex);
+ if (session->been_active)
+ goto active; /* Refuse to add channel to active session */
+ transport = lttng_transport_find(transport_name);
+ if (!transport) {
+ printk(KERN_WARNING "LTTng transport %s not found\n",
+ transport_name);
+ goto notransport;
+ }
+ if (!try_module_get(transport->owner)) {
+ printk(KERN_WARNING "LTT : Can't lock transport module.\n");
+ goto notransport;
+ }
+ chan = kzalloc(sizeof(struct lttng_channel), GFP_KERNEL);
+ if (!chan)
+ goto nomem;
+ chan->session = session;
+ chan->id = session->free_chan_id++;
+ /*
+ * Note: the channel creation op already writes into the packet
+ * headers. Therefore the "chan" information used as input
+ * should be already accessible.
+ */
+ chan->chan = transport->ops.channel_create("[lttng]", chan, buf_addr,
+ subbuf_size, num_subbuf, switch_timer_interval,
+ read_timer_interval);
+ if (!chan->chan)
+ goto create_error;
+ chan->enabled = 1;
+ chan->ops = &transport->ops;
+ chan->transport = transport;
+ list_add(&chan->list, &session->chan);
+ mutex_unlock(&sessions_mutex);
+ return chan;
+
+create_error:
+ kfree(chan);
+nomem:
+ if (transport)
+ module_put(transport->owner);
+notransport:
+active:
+ mutex_unlock(&sessions_mutex);
+ return NULL;
+}
+
+/*
+ * Only used internally at session destruction.
+ */
+static
+void _lttng_channel_destroy(struct lttng_channel *chan)
+{
+ chan->ops->channel_destroy(chan->chan);
+ module_put(chan->transport->owner);
+ list_del(&chan->list);
+ lttng_destroy_context(chan->ctx);
+ kfree(chan);
+}
+
+/*
+ * Supports event creation while tracing session is active.
+ */
+struct lttng_event *lttng_event_create(struct lttng_channel *chan,
+ struct lttng_kernel_event *event_param,
+ void *filter,
+ const struct lttng_event_desc *internal_desc)
+{
+ struct lttng_event *event;
+ int ret;
+
+ mutex_lock(&sessions_mutex);
+ if (chan->free_event_id == -1UL)
+ goto full;
+ /*
+ * This is O(n^2) (for each event, the loop is called at event
+ * creation). Might require a hash if we have lots of events.
+ */
+ list_for_each_entry(event, &chan->session->events, list)
+ if (!strcmp(event->desc->name, event_param->name))
+ goto exist;
+ event = kmem_cache_zalloc(event_cache, GFP_KERNEL);
+ if (!event)
+ goto cache_error;
+ event->chan = chan;
+ event->filter = filter;
+ event->id = chan->free_event_id++;
+ event->enabled = 1;
+ event->instrumentation = event_param->instrumentation;
+ /* Populate lttng_event structure before tracepoint registration. */
+ smp_wmb();
+ switch (event_param->instrumentation) {
+ case LTTNG_KERNEL_TRACEPOINT:
+ event->desc = lttng_event_get(event_param->name);
+ if (!event->desc)
+ goto register_error;
+ ret = tracepoint_probe_register(event_param->name,
+ event->desc->probe_callback,
+ event);
+ if (ret)
+ goto register_error;
+ break;
+ case LTTNG_KERNEL_KPROBE:
+ ret = lttng_kprobes_register(event_param->name,
+ event_param->u.kprobe.symbol_name,
+ event_param->u.kprobe.offset,
+ event_param->u.kprobe.addr,
+ event);
+ if (ret)
+ goto register_error;
+ ret = try_module_get(event->desc->owner);
+ WARN_ON_ONCE(!ret);
+ break;
+ case LTTNG_KERNEL_KRETPROBE:
+ {
+ struct lttng_event *event_return;
+
+ /* kretprobe defines 2 events */
+ event_return =
+ kmem_cache_zalloc(event_cache, GFP_KERNEL);
+ if (!event_return)
+ goto register_error;
+ event_return->chan = chan;
+ event_return->filter = filter;
+ event_return->id = chan->free_event_id++;
+ event_return->enabled = 1;
+ event_return->instrumentation = event_param->instrumentation;
+ /*
+ * Populate lttng_event structure before kretprobe registration.
+ */
+ smp_wmb();
+ ret = lttng_kretprobes_register(event_param->name,
+ event_param->u.kretprobe.symbol_name,
+ event_param->u.kretprobe.offset,
+ event_param->u.kretprobe.addr,
+ event, event_return);
+ if (ret) {
+ kmem_cache_free(event_cache, event_return);
+ goto register_error;
+ }
+ /* Take 2 refs on the module: one per event. */
+ ret = try_module_get(event->desc->owner);
+ WARN_ON_ONCE(!ret);
+ ret = try_module_get(event->desc->owner);
+ WARN_ON_ONCE(!ret);
+ ret = _lttng_event_metadata_statedump(chan->session, chan,
+ event_return);
+ if (ret) {
+ kmem_cache_free(event_cache, event_return);
+ module_put(event->desc->owner);
+ module_put(event->desc->owner);
+ goto statedump_error;
+ }
+ list_add(&event_return->list, &chan->session->events);
+ break;
+ }
+ case LTTNG_KERNEL_FUNCTION:
+ ret = lttng_ftrace_register(event_param->name,
+ event_param->u.ftrace.symbol_name,
+ event);
+ if (ret)
+ goto register_error;
+ ret = try_module_get(event->desc->owner);
+ WARN_ON_ONCE(!ret);
+ break;
+ case LTTNG_KERNEL_NOOP:
+ event->desc = internal_desc;
+ if (!event->desc)
+ goto register_error;
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ }
+ ret = _lttng_event_metadata_statedump(chan->session, chan, event);
+ if (ret)
+ goto statedump_error;
+ list_add(&event->list, &chan->session->events);
+ mutex_unlock(&sessions_mutex);
+ return event;
+
+statedump_error:
+ /* If a statedump error occurs, events will not be readable. */
+register_error:
+ kmem_cache_free(event_cache, event);
+cache_error:
+exist:
+full:
+ mutex_unlock(&sessions_mutex);
+ return NULL;
+}
+
+/*
+ * Only used internally at session destruction.
+ */
+int _lttng_event_unregister(struct lttng_event *event)
+{
+ int ret = -EINVAL;
+
+ switch (event->instrumentation) {
+ case LTTNG_KERNEL_TRACEPOINT:
+ ret = tracepoint_probe_unregister(event->desc->name,
+ event->desc->probe_callback,
+ event);
+ if (ret)
+ return ret;
+ break;
+ case LTTNG_KERNEL_KPROBE:
+ lttng_kprobes_unregister(event);
+ ret = 0;
+ break;
+ case LTTNG_KERNEL_KRETPROBE:
+ lttng_kretprobes_unregister(event);
+ ret = 0;
+ break;
+ case LTTNG_KERNEL_FUNCTION:
+ lttng_ftrace_unregister(event);
+ ret = 0;
+ break;
+ case LTTNG_KERNEL_NOOP:
+ ret = 0;
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ }
+ return ret;
+}
+
+/*
+ * Only used internally at session destruction.
+ */
+static
+void _lttng_event_destroy(struct lttng_event *event)
+{
+ switch (event->instrumentation) {
+ case LTTNG_KERNEL_TRACEPOINT:
+ lttng_event_put(event->desc);
+ break;
+ case LTTNG_KERNEL_KPROBE:
+ module_put(event->desc->owner);
+ lttng_kprobes_destroy_private(event);
+ break;
+ case LTTNG_KERNEL_KRETPROBE:
+ module_put(event->desc->owner);
+ lttng_kretprobes_destroy_private(event);
+ break;
+ case LTTNG_KERNEL_FUNCTION:
+ module_put(event->desc->owner);
+ lttng_ftrace_destroy_private(event);
+ break;
+ case LTTNG_KERNEL_NOOP:
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ }
+ list_del(&event->list);
+ lttng_destroy_context(event->ctx);
+ kmem_cache_free(event_cache, event);
+}
+
+/*
+ * We have exclusive access to our metadata buffer (protected by the
+ * sessions_mutex), so we can do racy operations such as looking for
+ * remaining space left in packet and write, since mutual exclusion
+ * protects us from concurrent writes.
+ */
+int lttng_metadata_printf(struct lttng_session *session,
+ const char *fmt, ...)
+{
+ struct lib_ring_buffer_ctx ctx;
+ struct lttng_channel *chan = session->metadata;
+ char *str;
+ int ret = 0, waitret;
+ size_t len, reserve_len, pos;
+ va_list ap;
+
+ WARN_ON_ONCE(!ACCESS_ONCE(session->active));
+
+ va_start(ap, fmt);
+ str = kvasprintf(GFP_KERNEL, fmt, ap);
+ va_end(ap);
+ if (!str)
+ return -ENOMEM;
+
+ len = strlen(str);
+ pos = 0;
+
+ for (pos = 0; pos < len; pos += reserve_len) {
+ reserve_len = min_t(size_t,
+ chan->ops->packet_avail_size(chan->chan),
+ len - pos);
+ lib_ring_buffer_ctx_init(&ctx, chan->chan, NULL, reserve_len,
+ sizeof(char), -1);
+ /*
+ * We don't care about metadata buffer's records lost
+ * count, because we always retry here. Report error if
+ * we need to bail out after timeout or being
+ * interrupted.
+ */
+ waitret = wait_event_interruptible_timeout(*chan->ops->get_writer_buf_wait_queue(chan->chan, -1),
+ ({
+ ret = chan->ops->event_reserve(&ctx, 0);
+ ret != -ENOBUFS || !ret;
+ }),
+ msecs_to_jiffies(LTTNG_METADATA_TIMEOUT_MSEC));
+ if (!waitret || waitret == -ERESTARTSYS || ret) {
+ printk(KERN_WARNING "LTTng: Failure to write metadata to buffers (%s)\n",
+ waitret == -ERESTARTSYS ? "interrupted" :
+ (ret == -ENOBUFS ? "timeout" : "I/O error"));
+ if (waitret == -ERESTARTSYS)
+ ret = waitret;
+ goto end;
+ }
+ chan->ops->event_write(&ctx, &str[pos], reserve_len);
+ chan->ops->event_commit(&ctx);
+ }
+end:
+ kfree(str);
+ return ret;
+}
+
+static
+int _lttng_field_statedump(struct lttng_session *session,
+ const struct lttng_event_field *field)
+{
+ int ret = 0;
+
+ switch (field->type.atype) {
+ case atype_integer:
+ ret = lttng_metadata_printf(session,
+ " integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } _%s;\n",
+ field->type.u.basic.integer.size,
+ field->type.u.basic.integer.alignment,
+ field->type.u.basic.integer.signedness,
+ (field->type.u.basic.integer.encoding == lttng_encode_none)
+ ? "none"
+ : (field->type.u.basic.integer.encoding == lttng_encode_UTF8)
+ ? "UTF8"
+ : "ASCII",
+ field->type.u.basic.integer.base,
+#ifdef __BIG_ENDIAN
+ field->type.u.basic.integer.reverse_byte_order ? " byte_order = le;" : "",
+#else
+ field->type.u.basic.integer.reverse_byte_order ? " byte_order = be;" : "",
+#endif
+ field->name);
+ break;
+ case atype_enum:
+ ret = lttng_metadata_printf(session,
+ " %s _%s;\n",
+ field->type.u.basic.enumeration.name,
+ field->name);
+ break;
+ case atype_array:
+ {
+ const struct lttng_basic_type *elem_type;
+
+ elem_type = &field->type.u.array.elem_type;
+ ret = lttng_metadata_printf(session,
+ " integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } _%s[%u];\n",
+ elem_type->u.basic.integer.size,
+ elem_type->u.basic.integer.alignment,
+ elem_type->u.basic.integer.signedness,
+ (elem_type->u.basic.integer.encoding == lttng_encode_none)
+ ? "none"
+ : (elem_type->u.basic.integer.encoding == lttng_encode_UTF8)
+ ? "UTF8"
+ : "ASCII",
+ elem_type->u.basic.integer.base,
+#ifdef __BIG_ENDIAN
+ elem_type->u.basic.integer.reverse_byte_order ? " byte_order = le;" : "",
+#else
+ elem_type->u.basic.integer.reverse_byte_order ? " byte_order = be;" : "",
+#endif
+ field->name, field->type.u.array.length);
+ break;
+ }
+ case atype_sequence:
+ {
+ const struct lttng_basic_type *elem_type;
+ const struct lttng_basic_type *length_type;
+
+ elem_type = &field->type.u.sequence.elem_type;
+ length_type = &field->type.u.sequence.length_type;
+ ret = lttng_metadata_printf(session,
+ " integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } __%s_length;\n",
+ length_type->u.basic.integer.size,
+ (unsigned int) length_type->u.basic.integer.alignment,
+ length_type->u.basic.integer.signedness,
+ (length_type->u.basic.integer.encoding == lttng_encode_none)
+ ? "none"
+ : ((length_type->u.basic.integer.encoding == lttng_encode_UTF8)
+ ? "UTF8"
+ : "ASCII"),
+ length_type->u.basic.integer.base,
+#ifdef __BIG_ENDIAN
+ length_type->u.basic.integer.reverse_byte_order ? " byte_order = le;" : "",
+#else
+ length_type->u.basic.integer.reverse_byte_order ? " byte_order = be;" : "",
+#endif
+ field->name);
+ if (ret)
+ return ret;
+
+ ret = lttng_metadata_printf(session,
+ " integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } _%s[ __%s_length ];\n",
+ elem_type->u.basic.integer.size,
+ (unsigned int) elem_type->u.basic.integer.alignment,
+ elem_type->u.basic.integer.signedness,
+ (elem_type->u.basic.integer.encoding == lttng_encode_none)
+ ? "none"
+ : ((elem_type->u.basic.integer.encoding == lttng_encode_UTF8)
+ ? "UTF8"
+ : "ASCII"),
+ elem_type->u.basic.integer.base,
+#ifdef __BIG_ENDIAN
+ elem_type->u.basic.integer.reverse_byte_order ? " byte_order = le;" : "",
+#else
+ elem_type->u.basic.integer.reverse_byte_order ? " byte_order = be;" : "",
+#endif
+ field->name,
+ field->name);
+ break;
+ }
+
+ case atype_string:
+ /* Default encoding is UTF8 */
+ ret = lttng_metadata_printf(session,
+ " string%s _%s;\n",
+ field->type.u.basic.string.encoding == lttng_encode_ASCII ?
+ " { encoding = ASCII; }" : "",
+ field->name);
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ return -EINVAL;
+ }
+ return ret;
+}
+
+static
+int _lttng_context_metadata_statedump(struct lttng_session *session,
+ struct lttng_ctx *ctx)
+{
+ int ret = 0;
+ int i;
+
+ if (!ctx)
+ return 0;
+ for (i = 0; i < ctx->nr_fields; i++) {
+ const struct lttng_ctx_field *field = &ctx->fields[i];
+
+ ret = _lttng_field_statedump(session, &field->event_field);
+ if (ret)
+ return ret;
+ }
+ return ret;
+}
+
+static
+int _lttng_fields_metadata_statedump(struct lttng_session *session,
+ struct lttng_event *event)
+{
+ const struct lttng_event_desc *desc = event->desc;
+ int ret = 0;
+ int i;
+
+ for (i = 0; i < desc->nr_fields; i++) {
+ const struct lttng_event_field *field = &desc->fields[i];
+
+ ret = _lttng_field_statedump(session, field);
+ if (ret)
+ return ret;
+ }
+ return ret;
+}
+
+static
+int _lttng_event_metadata_statedump(struct lttng_session *session,
+ struct lttng_channel *chan,
+ struct lttng_event *event)
+{
+ int ret = 0;
+
+ if (event->metadata_dumped || !ACCESS_ONCE(session->active))
+ return 0;
+ if (chan == session->metadata)
+ return 0;
+
+ ret = lttng_metadata_printf(session,
+ "event {\n"
+ " name = %s;\n"
+ " id = %u;\n"
+ " stream_id = %u;\n",
+ event->desc->name,
+ event->id,
+ event->chan->id);
+ if (ret)
+ goto end;
+
+ if (event->ctx) {
+ ret = lttng_metadata_printf(session,
+ " context := struct {\n");
+ if (ret)
+ goto end;
+ }
+ ret = _lttng_context_metadata_statedump(session, event->ctx);
+ if (ret)
+ goto end;
+ if (event->ctx) {
+ ret = lttng_metadata_printf(session,
+ " };\n");
+ if (ret)
+ goto end;
+ }
+
+ ret = lttng_metadata_printf(session,
+ " fields := struct {\n"
+ );
+ if (ret)
+ goto end;
+
+ ret = _lttng_fields_metadata_statedump(session, event);
+ if (ret)
+ goto end;
+
+ /*
+ * LTTng space reservation can only reserve multiples of the
+ * byte size.
+ */
+ ret = lttng_metadata_printf(session,
+ " };\n"
+ "};\n\n");
+ if (ret)
+ goto end;
+
+ event->metadata_dumped = 1;
+end:
+ return ret;
+
+}
+
+static
+int _lttng_channel_metadata_statedump(struct lttng_session *session,
+ struct lttng_channel *chan)
+{
+ int ret = 0;
+
+ if (chan->metadata_dumped || !ACCESS_ONCE(session->active))
+ return 0;
+ if (chan == session->metadata)
+ return 0;
+
+ WARN_ON_ONCE(!chan->header_type);
+ ret = lttng_metadata_printf(session,
+ "stream {\n"
+ " id = %u;\n"
+ " event.header := %s;\n"
+ " packet.context := struct packet_context;\n",
+ chan->id,
+ chan->header_type == 1 ? "struct event_header_compact" :
+ "struct event_header_large");
+ if (ret)
+ goto end;
+
+ if (chan->ctx) {
+ ret = lttng_metadata_printf(session,
+ " event.context := struct {\n");
+ if (ret)
+ goto end;
+ }
+ ret = _lttng_context_metadata_statedump(session, chan->ctx);
+ if (ret)
+ goto end;
+ if (chan->ctx) {
+ ret = lttng_metadata_printf(session,
+ " };\n");
+ if (ret)
+ goto end;
+ }
+
+ ret = lttng_metadata_printf(session,
+ "};\n\n");
+
+ chan->metadata_dumped = 1;
+end:
+ return ret;
+}
+
+static
+int _lttng_stream_packet_context_declare(struct lttng_session *session)
+{
+ return lttng_metadata_printf(session,
+ "struct packet_context {\n"
+ " uint64_t timestamp_begin;\n"
+ " uint64_t timestamp_end;\n"
+ " uint32_t events_discarded;\n"
+ " uint32_t content_size;\n"
+ " uint32_t packet_size;\n"
+ " uint32_t cpu_id;\n"
+ "};\n\n"
+ );
+}
+
+/*
+ * Compact header:
+ * id: range: 0 - 30.
+ * id 31 is reserved to indicate an extended header.
+ *
+ * Large header:
+ * id: range: 0 - 65534.
+ * id 65535 is reserved to indicate an extended header.
+ */
+static
+int _lttng_event_header_declare(struct lttng_session *session)
+{
+ return lttng_metadata_printf(session,
+ "struct event_header_compact {\n"
+ " enum : uint5_t { compact = 0 ... 30, extended = 31 } id;\n"
+ " variant <id> {\n"
+ " struct {\n"
+ " uint27_t timestamp;\n"
+ " } compact;\n"
+ " struct {\n"
+ " uint32_t id;\n"
+ " uint64_t timestamp;\n"
+ " } extended;\n"
+ " } v;\n"
+ "} align(%u);\n"
+ "\n"
+ "struct event_header_large {\n"
+ " enum : uint16_t { compact = 0 ... 65534, extended = 65535 } id;\n"
+ " variant <id> {\n"
+ " struct {\n"
+ " uint32_t timestamp;\n"
+ " } compact;\n"
+ " struct {\n"
+ " uint32_t id;\n"
+ " uint64_t timestamp;\n"
+ " } extended;\n"
+ " } v;\n"
+ "} align(%u);\n\n",
+ lttng_alignof(uint32_t) * CHAR_BIT,
+ lttng_alignof(uint16_t) * CHAR_BIT
+ );
+}
+
+/*
+ * Output metadata into this session's metadata buffers.
+ */
+static
+int _lttng_session_metadata_statedump(struct lttng_session *session)
+{
+ unsigned char *uuid_c = session->uuid.b;
+ unsigned char uuid_s[37];
+ struct lttng_channel *chan;
+ struct lttng_event *event;
+ int ret = 0;
+
+ if (!ACCESS_ONCE(session->active))
+ return 0;
+ if (session->metadata_dumped)
+ goto skip_session;
+ if (!session->metadata) {
+ printk(KERN_WARNING "LTTng: attempt to start tracing, but metadata channel is not found. Operation abort.\n");
+ return -EPERM;
+ }
+
+ snprintf(uuid_s, sizeof(uuid_s),
+ "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",
+ uuid_c[0], uuid_c[1], uuid_c[2], uuid_c[3],
+ uuid_c[4], uuid_c[5], uuid_c[6], uuid_c[7],
+ uuid_c[8], uuid_c[9], uuid_c[10], uuid_c[11],
+ uuid_c[12], uuid_c[13], uuid_c[14], uuid_c[15]);
+
+ ret = lttng_metadata_printf(session,
+ "typealias integer { size = 8; align = %u; signed = false; } := uint8_t;\n"
+ "typealias integer { size = 16; align = %u; signed = false; } := uint16_t;\n"
+ "typealias integer { size = 32; align = %u; signed = false; } := uint32_t;\n"
+ "typealias integer { size = 64; align = %u; signed = false; } := uint64_t;\n"
+ "typealias integer { size = 5; align = 1; signed = false; } := uint5_t;\n"
+ "typealias integer { size = 27; align = 1; signed = false; } := uint27_t;\n"
+ "\n"
+ "trace {\n"
+ " major = %u;\n"
+ " minor = %u;\n"
+ " uuid = \"%s\";\n"
+ " byte_order = %s;\n"
+ " packet.header := struct {\n"
+ " uint32_t magic;\n"
+ " uint8_t uuid[16];\n"
+ " uint32_t stream_id;\n"
+ " };\n"
+ "};\n\n",
+ lttng_alignof(uint8_t) * CHAR_BIT,
+ lttng_alignof(uint16_t) * CHAR_BIT,
+ lttng_alignof(uint32_t) * CHAR_BIT,
+ lttng_alignof(uint64_t) * CHAR_BIT,
+ CTF_VERSION_MAJOR,
+ CTF_VERSION_MINOR,
+ uuid_s,
+#ifdef __BIG_ENDIAN
+ "be"
+#else
+ "le"
+#endif
+ );
+ if (ret)
+ goto end;
+
+ ret = _lttng_stream_packet_context_declare(session);
+ if (ret)
+ goto end;
+
+ ret = _lttng_event_header_declare(session);
+ if (ret)
+ goto end;
+
+skip_session:
+ list_for_each_entry(chan, &session->chan, list) {
+ ret = _lttng_channel_metadata_statedump(session, chan);
+ if (ret)
+ goto end;
+ }
+
+ list_for_each_entry(event, &session->events, list) {
+ ret = _lttng_event_metadata_statedump(session, event->chan, event);
+ if (ret)
+ goto end;
+ }
+ session->metadata_dumped = 1;
+end:
+ return ret;
+}
+
+/**
+ * lttng_transport_register - LTT transport registration
+ * @transport: transport structure
+ *
+ * Registers a transport which can be used as output to extract the data out of
+ * LTTng. The module calling this registration function must ensure that no
+ * trap-inducing code will be executed by the transport functions. E.g.
+ * vmalloc_sync_all() must be called between a vmalloc and the moment the memory
+ * is made visible to the transport function. This registration acts as a
+ * vmalloc_sync_all. Therefore, only if the module allocates virtual memory
+ * after its registration must it synchronize the TLBs.
+ */
+void lttng_transport_register(struct lttng_transport *transport)
+{
+ /*
+ * Make sure no page fault can be triggered by the module about to be
+ * registered. We deal with this here so we don't have to call
+ * vmalloc_sync_all() in each module's init.
+ */
+ wrapper_vmalloc_sync_all();
+
+ mutex_lock(&sessions_mutex);
+ list_add_tail(&transport->node, <tng_transport_list);
+ mutex_unlock(&sessions_mutex);
+}
+EXPORT_SYMBOL_GPL(lttng_transport_register);
+
+/**
+ * lttng_transport_unregister - LTT transport unregistration
+ * @transport: transport structure
+ */
+void lttng_transport_unregister(struct lttng_transport *transport)
+{
+ mutex_lock(&sessions_mutex);
+ list_del(&transport->node);
+ mutex_unlock(&sessions_mutex);
+}
+EXPORT_SYMBOL_GPL(lttng_transport_unregister);
+
+static int __init lttng_events_init(void)
+{
+ int ret;
+
+ event_cache = KMEM_CACHE(lttng_event, 0);
+ if (!event_cache)
+ return -ENOMEM;
+ ret = lttng_abi_init();
+ if (ret)
+ goto error_abi;
+ return 0;
+error_abi:
+ kmem_cache_destroy(event_cache);
+ return ret;
+}
+
+module_init(lttng_events_init);
+
+static void __exit lttng_events_exit(void)
+{
+ struct lttng_session *session, *tmpsession;
+
+ lttng_abi_exit();
+ list_for_each_entry_safe(session, tmpsession, &sessions, list)
+ lttng_session_destroy(session);
+ kmem_cache_destroy(event_cache);
+}
+
+module_exit(lttng_events_exit);
+
+MODULE_LICENSE("GPL and additional rights");
+MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>");
+MODULE_DESCRIPTION("LTTng Events");
projects / lttng-modules.git / commitdiff
