Commit changes prior to shmp read-only header
[lttng-ust.git] / libust / ltt-events.c
index a94e8f9a1dde6a6e315133e59c66e3659455f99d..f048e27817a69cb9f1aee3c23f41c4d1360341a7 100644 (file)
@@ -8,21 +8,27 @@
  * 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 <linux/uuid.h>
-#include "wrapper/vmalloc.h"   /* for wrapper_vmalloc_sync_all() */
-#include "ltt-events.h"
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <urcu/list.h>
+#include <pthread.h>
+#include <urcu-bp.h>
+#include <urcu/compiler.h>
+#include <urcu/uatomic.h>
+#include <uuid/uuid.h>
+#include <ust/tracepoint.h>
+#include <errno.h>
+#include <sys/shm.h>
+#include <sys/ipc.h>
+#include <ust/lttng-events.h>
+#include "usterr_signal_safe.h"
+#include "ust/core.h"
 #include "ltt-tracer.h"
+#include "ust/wait.h"
 
-static LIST_HEAD(sessions);
-static LIST_HEAD(ltt_transport_list);
+static CDS_LIST_HEAD(sessions);
+static CDS_LIST_HEAD(ltt_transport_list);
 static DEFINE_MUTEX(sessions_mutex);
-static struct kmem_cache *event_cache;
 
 static void _ltt_event_destroy(struct ltt_event *event);
 static void _ltt_channel_destroy(struct ltt_channel *chan);
@@ -34,29 +40,24 @@ int _ltt_event_metadata_statedump(struct ltt_session *session,
 static
 int _ltt_session_metadata_statedump(struct ltt_session *session);
 
-
-static
 void synchronize_trace(void)
 {
-       synchronize_sched();
-#ifdef CONFIG_PREEMPT_RT
        synchronize_rcu();
-#endif
 }
 
 struct ltt_session *ltt_session_create(void)
 {
        struct ltt_session *session;
 
-       mutex_lock(&sessions_mutex);
-       session = kzalloc(sizeof(struct ltt_session), GFP_KERNEL);
+       pthread_mutex_lock(&sessions_mutex);
+       session = zmalloc(sizeof(struct ltt_session));
        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);
+       CDS_INIT_LIST_HEAD(&session->chan);
+       CDS_INIT_LIST_HEAD(&session->events);
+       uuid_generate(session->uuid);
+       cds_list_add(&session->list, &sessions);
+       pthread_mutex_unlock(&sessions_mutex);
        return session;
 }
 
@@ -66,20 +67,20 @@ void ltt_session_destroy(struct ltt_session *session)
        struct ltt_event *event, *tmpevent;
        int ret;
 
-       mutex_lock(&sessions_mutex);
-       ACCESS_ONCE(session->active) = 0;
-       list_for_each_entry(event, &session->events, list) {
+       pthread_mutex_lock(&sessions_mutex);
+       CMM_ACCESS_ONCE(session->active) = 0;
+       cds_list_for_each_entry(event, &session->events, list) {
                ret = _ltt_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)
+       cds_list_for_each_entry_safe(event, tmpevent, &session->events, list)
                _ltt_event_destroy(event);
-       list_for_each_entry_safe(chan, tmpchan, &session->chan, list)
+       cds_list_for_each_entry_safe(chan, tmpchan, &session->chan, list)
                _ltt_channel_destroy(chan);
-       list_del(&session->list);
-       mutex_unlock(&sessions_mutex);
-       kfree(session);
+       cds_list_del(&session->list);
+       pthread_mutex_unlock(&sessions_mutex);
+       free(session);
 }
 
 int ltt_session_enable(struct ltt_session *session)
@@ -87,7 +88,7 @@ int ltt_session_enable(struct ltt_session *session)
        int ret = 0;
        struct ltt_channel *chan;
 
-       mutex_lock(&sessions_mutex);
+       pthread_mutex_lock(&sessions_mutex);
        if (session->active) {
                ret = -EBUSY;
                goto end;
@@ -97,7 +98,7 @@ int ltt_session_enable(struct ltt_session *session)
         * 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) {
+       cds_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)
@@ -106,16 +107,13 @@ int ltt_session_enable(struct ltt_session *session)
                        chan->header_type = 2;  /* large */
        }
 
-       ACCESS_ONCE(session->active) = 1;
-       ACCESS_ONCE(session->been_active) = 1;
-       synchronize_trace();    /* Wait for in-flight events to complete */
+       CMM_ACCESS_ONCE(session->active) = 1;
+       CMM_ACCESS_ONCE(session->been_active) = 1;
        ret = _ltt_session_metadata_statedump(session);
-       if (ret) {
-               ACCESS_ONCE(session->active) = 0;
-               synchronize_trace();    /* Wait for in-flight events to complete */
-       }
+       if (ret)
+               CMM_ACCESS_ONCE(session->active) = 0;
 end:
-       mutex_unlock(&sessions_mutex);
+       pthread_mutex_unlock(&sessions_mutex);
        return ret;
 }
 
@@ -123,15 +121,14 @@ int ltt_session_disable(struct ltt_session *session)
 {
        int ret = 0;
 
-       mutex_lock(&sessions_mutex);
+       pthread_mutex_lock(&sessions_mutex);
        if (!session->active) {
                ret = -EBUSY;
                goto end;
        }
-       ACCESS_ONCE(session->active) = 0;
-       synchronize_trace();    /* Wait for in-flight events to complete */
+       CMM_ACCESS_ONCE(session->active) = 0;
 end:
-       mutex_unlock(&sessions_mutex);
+       pthread_mutex_unlock(&sessions_mutex);
        return ret;
 }
 
@@ -139,7 +136,9 @@ int ltt_channel_enable(struct ltt_channel *channel)
 {
        int old;
 
-       old = xchg(&channel->enabled, 1);
+       if (channel == channel->session->metadata)
+               return -EPERM;
+       old = uatomic_xchg(&channel->enabled, 1);
        if (old)
                return -EEXIST;
        return 0;
@@ -149,7 +148,9 @@ int ltt_channel_disable(struct ltt_channel *channel)
 {
        int old;
 
-       old = xchg(&channel->enabled, 0);
+       if (channel == channel->session->metadata)
+               return -EPERM;
+       old = uatomic_xchg(&channel->enabled, 0);
        if (!old)
                return -EEXIST;
        return 0;
@@ -159,7 +160,9 @@ int ltt_event_enable(struct ltt_event *event)
 {
        int old;
 
-       old = xchg(&event->enabled, 1);
+       if (event->chan == event->chan->session->metadata)
+               return -EPERM;
+       old = uatomic_xchg(&event->enabled, 1);
        if (old)
                return -EEXIST;
        return 0;
@@ -169,7 +172,9 @@ int ltt_event_disable(struct ltt_event *event)
 {
        int old;
 
-       old = xchg(&event->enabled, 0);
+       if (event->chan == event->chan->session->metadata)
+               return -EPERM;
+       old = uatomic_xchg(&event->enabled, 0);
        if (!old)
                return -EEXIST;
        return 0;
@@ -179,7 +184,7 @@ static struct ltt_transport *ltt_transport_find(const char *name)
 {
        struct ltt_transport *transport;
 
-       list_for_each_entry(transport, &ltt_transport_list, node) {
+       cds_list_for_each_entry(transport, &ltt_transport_list, node) {
                if (!strcmp(transport->name, name))
                        return transport;
        }
@@ -196,20 +201,21 @@ struct ltt_channel *ltt_channel_create(struct ltt_session *session,
        struct ltt_channel *chan;
        struct ltt_transport *transport;
 
-       mutex_lock(&sessions_mutex);
+       pthread_mutex_lock(&sessions_mutex);
        if (session->been_active)
                goto active;    /* Refuse to add channel to active session */
        transport = ltt_transport_find(transport_name);
        if (!transport) {
-               printk(KERN_WARNING "LTTng transport %s not found\n",
+               DBG("LTTng transport %s not found\n",
                       transport_name);
                goto notransport;
        }
-       chan = kzalloc(sizeof(struct ltt_channel), GFP_KERNEL);
+       chan = zmalloc(sizeof(struct ltt_channel));
        if (!chan)
                goto nomem;
        chan->session = session;
        chan->id = session->free_chan_id++;
+       //chan->shmid = shmget(getpid(), shmlen, IPC_CREAT | IPC_EXCL | 0700);
        /*
         * Note: the channel creation op already writes into the packet
         * headers. Therefore the "chan" information used as input
@@ -217,21 +223,21 @@ struct ltt_channel *ltt_channel_create(struct ltt_session *session,
         */
        chan->chan = transport->ops.channel_create("[lttng]", chan, buf_addr,
                        subbuf_size, num_subbuf, switch_timer_interval,
-                       read_timer_interval);
+                       read_timer_interval, shmid);
        if (!chan->chan)
                goto create_error;
        chan->enabled = 1;
        chan->ops = &transport->ops;
-       list_add(&chan->list, &session->chan);
-       mutex_unlock(&sessions_mutex);
+       cds_list_add(&chan->list, &session->chan);
+       pthread_mutex_unlock(&sessions_mutex);
        return chan;
 
 create_error:
-       kfree(chan);
+       free(chan);
 nomem:
 notransport:
 active:
-       mutex_unlock(&sessions_mutex);
+       pthread_mutex_unlock(&sessions_mutex);
        return NULL;
 }
 
@@ -242,32 +248,32 @@ static
 void _ltt_channel_destroy(struct ltt_channel *chan)
 {
        chan->ops->channel_destroy(chan->chan);
-       list_del(&chan->list);
+       cds_list_del(&chan->list);
        lttng_destroy_context(chan->ctx);
-       kfree(chan);
+       free(chan);
 }
 
 /*
  * Supports event creation while tracing session is active.
  */
 struct ltt_event *ltt_event_create(struct ltt_channel *chan,
-                                  struct lttng_kernel_event *event_param,
+                                  struct lttng_ust_event *event_param,
                                   void *filter)
 {
        struct ltt_event *event;
        int ret;
 
-       mutex_lock(&sessions_mutex);
+       pthread_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)
+       cds_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);
+       event = zmalloc(sizeof(struct ltt_event));
        if (!event)
                goto cache_error;
        event->chan = chan;
@@ -276,59 +282,39 @@ struct ltt_event *ltt_event_create(struct ltt_channel *chan,
        event->enabled = 1;
        event->instrumentation = event_param->instrumentation;
        /* Populate ltt_event structure before tracepoint registration. */
-       smp_wmb();
+       cmm_smp_wmb();
        switch (event_param->instrumentation) {
-       case LTTNG_KERNEL_TRACEPOINT:
+       case LTTNG_UST_TRACEPOINT:
                event->desc = ltt_event_get(event_param->name);
                if (!event->desc)
                        goto register_error;
-               ret = tracepoint_probe_register(event_param->name,
+               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_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;
        default:
                WARN_ON_ONCE(1);
        }
        ret = _ltt_event_metadata_statedump(chan->session, chan, event);
        if (ret)
                goto statedump_error;
-       list_add(&event->list, &chan->session->events);
-       mutex_unlock(&sessions_mutex);
+       cds_list_add(&event->list, &chan->session->events);
+       pthread_mutex_unlock(&sessions_mutex);
        return event;
 
 statedump_error:
-       WARN_ON_ONCE(tracepoint_probe_unregister(event_param->name,
+       WARN_ON_ONCE(__tracepoint_probe_unregister(event_param->name,
                                event->desc->probe_callback,
                                event));
        ltt_event_put(event->desc);
 register_error:
-       kmem_cache_free(event_cache, event);
+       free(event);
 cache_error:
 exist:
 full:
-       mutex_unlock(&sessions_mutex);
+       pthread_mutex_unlock(&sessions_mutex);
        return NULL;
 }
 
@@ -340,21 +326,13 @@ int _ltt_event_unregister(struct ltt_event *event)
        int ret = -EINVAL;
 
        switch (event->instrumentation) {
-       case LTTNG_KERNEL_TRACEPOINT:
-               ret = tracepoint_probe_unregister(event->desc->name,
+       case LTTNG_UST_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_FUNCTION:
-               lttng_ftrace_unregister(event);
-               ret = 0;
-               break;
        default:
                WARN_ON_ONCE(1);
        }
@@ -368,23 +346,15 @@ static
 void _ltt_event_destroy(struct ltt_event *event)
 {
        switch (event->instrumentation) {
-       case LTTNG_KERNEL_TRACEPOINT:
+       case LTTNG_UST_TRACEPOINT:
                ltt_event_put(event->desc);
                break;
-       case LTTNG_KERNEL_KPROBE:
-               module_put(event->desc->owner);
-               lttng_kprobes_destroy_private(event);
-               break;
-       case LTTNG_KERNEL_FUNCTION:
-               module_put(event->desc->owner);
-               lttng_ftrace_destroy_private(event);
-               break;
        default:
                WARN_ON_ONCE(1);
        }
-       list_del(&event->list);
+       cds_list_del(&event->list);
        lttng_destroy_context(event->ctx);
-       kmem_cache_free(event_cache, event);
+       free(event);
 }
 
 /*
@@ -398,17 +368,17 @@ int lttng_metadata_printf(struct ltt_session *session,
 {
        struct lib_ring_buffer_ctx ctx;
        struct ltt_channel *chan = session->metadata;
-       char *str;
+       char *str = NULL;
        int ret = 0, waitret;
        size_t len, reserve_len, pos;
        va_list ap;
 
-       WARN_ON_ONCE(!ACCESS_ONCE(session->active));
+       WARN_ON_ONCE(!CMM_ACCESS_ONCE(session->active));
 
        va_start(ap, fmt);
-       str = kvasprintf(GFP_KERNEL, fmt, ap);
+       ret = vasprintf(&str, fmt, ap);
        va_end(ap);
-       if (!str)
+       if (ret < 0)
                return -ENOMEM;
 
        len = strlen(str);
@@ -426,17 +396,17 @@ int lttng_metadata_printf(struct ltt_session *session,
                 * we need to bail out after timeout or being
                 * interrupted.
                 */
-               waitret = wait_event_interruptible_timeout(*chan->ops->get_reader_wait_queue(chan->chan),
+               waitret = wait_cond_interruptible_timeout(
                        ({
                                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" :
+                       LTTNG_METADATA_TIMEOUT_MSEC);
+               if (!waitret || waitret == -EINTR || ret) {
+                       DBG("LTTng: Failure to write metadata to buffers (%s)\n",
+                               waitret == -EINTR ? "interrupted" :
                                        (ret == -ENOBUFS ? "timeout" : "I/O error"));
-                       if (waitret == -ERESTARTSYS)
+                       if (waitret == -EINTR)
                                ret = waitret;
                        goto end;
                }
@@ -444,7 +414,7 @@ int lttng_metadata_printf(struct ltt_session *session,
                chan->ops->event_commit(&ctx);
        }
 end:
-       kfree(str);
+       free(str);
        return ret;
 }
 
@@ -471,6 +441,19 @@ int _ltt_field_statedump(struct ltt_session *session,
                        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_float:
+               ret = lttng_metadata_printf(session,
+                       "               floating_point { exp_dig = %u; mant_dig = %u; align = %u; } %s;\n",
+                       field->type.u.basic._float.exp_dig,
+                       field->type.u.basic._float.mant_dig,
+                       field->type.u.basic._float.alignment,
+#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;
@@ -611,7 +594,7 @@ int _ltt_event_metadata_statedump(struct ltt_session *session,
 {
        int ret = 0;
 
-       if (event->metadata_dumped || !ACCESS_ONCE(session->active))
+       if (event->metadata_dumped || !CMM_ACCESS_ONCE(session->active))
                return 0;
        if (chan == session->metadata)
                return 0;
@@ -675,7 +658,7 @@ int _ltt_channel_metadata_statedump(struct ltt_session *session,
 {
        int ret = 0;
 
-       if (chan->metadata_dumped || !ACCESS_ONCE(session->active))
+       if (chan->metadata_dumped || !CMM_ACCESS_ONCE(session->active))
                return 0;
        if (chan == session->metadata)
                return 0;
@@ -780,18 +763,18 @@ int _ltt_event_header_declare(struct ltt_session *session)
 static
 int _ltt_session_metadata_statedump(struct ltt_session *session)
 {
-       unsigned char *uuid_c = session->uuid.b;
-       unsigned char uuid_s[37];
+       unsigned char *uuid_c = session->uuid;
+       char uuid_s[37];
        struct ltt_channel *chan;
        struct ltt_event *event;
        int ret = 0;
 
-       if (!ACCESS_ONCE(session->active))
+       if (!CMM_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");
+               DBG("LTTng: attempt to start tracing, but metadata channel is not found. Operation abort.\n");
                return -EPERM;
        }
 
@@ -846,13 +829,13 @@ int _ltt_session_metadata_statedump(struct ltt_session *session)
                goto end;
 
 skip_session:
-       list_for_each_entry(chan, &session->chan, list) {
+       cds_list_for_each_entry(chan, &session->chan, list) {
                ret = _ltt_channel_metadata_statedump(session, chan);
                if (ret)
                        goto end;
        }
 
-       list_for_each_entry(event, &session->events, list) {
+       cds_list_for_each_entry(event, &session->events, list) {
                ret = _ltt_event_metadata_statedump(session, event->chan, event);
                if (ret)
                        goto end;
@@ -867,27 +850,14 @@ end:
  * @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.
+ * LTTng.
  */
 void ltt_transport_register(struct ltt_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, &ltt_transport_list);
-       mutex_unlock(&sessions_mutex);
+       pthread_mutex_lock(&sessions_mutex);
+       cds_list_add_tail(&transport->node, &ltt_transport_list);
+       pthread_mutex_unlock(&sessions_mutex);
 }
-EXPORT_SYMBOL_GPL(ltt_transport_register);
 
 /**
  * ltt_transport_unregister - LTT transport unregistration
@@ -895,42 +865,16 @@ EXPORT_SYMBOL_GPL(ltt_transport_register);
  */
 void ltt_transport_unregister(struct ltt_transport *transport)
 {
-       mutex_lock(&sessions_mutex);
-       list_del(&transport->node);
-       mutex_unlock(&sessions_mutex);
+       pthread_mutex_lock(&sessions_mutex);
+       cds_list_del(&transport->node);
+       pthread_mutex_unlock(&sessions_mutex);
 }
-EXPORT_SYMBOL_GPL(ltt_transport_unregister);
 
-static int __init ltt_events_init(void)
-{
-       int ret;
-
-       event_cache = KMEM_CACHE(ltt_event, 0);
-       if (!event_cache)
-               return -ENOMEM;
-       ret = ltt_debugfs_abi_init();
-       if (ret)
-               goto error_abi;
-       return 0;
-error_abi:
-       kmem_cache_destroy(event_cache);
-       return ret;
-}
-
-module_init(ltt_events_init);
-
-static void __exit ltt_events_exit(void)
+static
+void __attribute__((destructor)) ltt_events_exit(void)
 {
        struct ltt_session *session, *tmpsession;
 
-       ltt_debugfs_abi_exit();
-       list_for_each_entry_safe(session, tmpsession, &sessions, list)
+       cds_list_for_each_entry_safe(session, tmpsession, &sessions, list)
                ltt_session_destroy(session);
-       kmem_cache_destroy(event_cache);
 }
-
-module_exit(ltt_events_exit);
-
-MODULE_LICENSE("GPL and additional rights");
-MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>");
-MODULE_DESCRIPTION("LTTng Events");
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