Fix: userspace probe accessors are not const-correct
[lttng-tools.git] / src / bin / lttng-sessiond / trace-kernel.c
index 53053f2067c6a8b20cc92f0b6a3019fb360c473b..b9d03a72e002ca0042764a877f0ae556e87f1faa 100644 (file)
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-#define _GNU_SOURCE
+#define _LGPL_SOURCE
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 
+#include <lttng/event.h>
+#include <lttng/lttng-error.h>
+#include <lttng/userspace-probe.h>
+#include <lttng/userspace-probe-internal.h>
+
 #include <common/common.h>
 #include <common/defaults.h>
 
 #include "consumer.h"
 #include "trace-kernel.h"
+#include "lttng-sessiond.h"
+#include "notification-thread-commands.h"
 
 /*
  * Find the channel name for the given kernel session.
@@ -38,6 +45,13 @@ struct ltt_kernel_channel *trace_kernel_get_channel_by_name(
        assert(session);
        assert(name);
 
+       /*
+        * If we receive an empty string for channel name, it means the
+        * default channel name is requested.
+        */
+       if (name[0] == '\0')
+               name = DEFAULT_CHANNEL_NAME;
+
        DBG("Trying to find channel %s", name);
 
        cds_list_for_each_entry(chan, &session->channel_list.head, list) {
@@ -50,26 +64,79 @@ struct ltt_kernel_channel *trace_kernel_get_channel_by_name(
        return NULL;
 }
 
+/*
+ * Find the event for the given channel.
+ */
+struct ltt_kernel_event *trace_kernel_find_event(
+               char *name, struct ltt_kernel_channel *channel,
+               enum lttng_event_type type,
+               struct lttng_filter_bytecode *filter)
+{
+       struct ltt_kernel_event *ev;
+       int found = 0;
+
+       assert(name);
+       assert(channel);
+
+       cds_list_for_each_entry(ev, &channel->events_list.head, list) {
+               if (type != LTTNG_EVENT_ALL && ev->type != type) {
+                       continue;
+               }
+               if (strcmp(name, ev->event->name)) {
+                       continue;
+               }
+               if ((ev->filter && !filter) || (!ev->filter && filter)) {
+                       continue;
+               }
+               if (ev->filter && filter) {
+                       if (ev->filter->len != filter->len ||
+                                       memcmp(ev->filter->data, filter->data,
+                                               filter->len) != 0) {
+                               continue;
+                       }
+               }
+               found = 1;
+               break;
+       }
+       if (found) {
+               DBG("Found event %s for channel %s", name,
+                       channel->channel->name);
+               return ev;
+       } else {
+               return NULL;
+       }
+}
+
 /*
  * Find the event name for the given channel.
  */
 struct ltt_kernel_event *trace_kernel_get_event_by_name(
-               char *name, struct ltt_kernel_channel *channel)
+               char *name, struct ltt_kernel_channel *channel,
+               enum lttng_event_type type)
 {
        struct ltt_kernel_event *ev;
+       int found = 0;
 
        assert(name);
        assert(channel);
 
        cds_list_for_each_entry(ev, &channel->events_list.head, list) {
-               if (strcmp(name, ev->event->name) == 0) {
-                       DBG("Found event by name %s for channel %s", name,
-                                       channel->channel->name);
-                       return ev;
+               if (type != LTTNG_EVENT_ALL && ev->type != type) {
+                       continue;
+               }
+               if (strcmp(name, ev->event->name)) {
+                       continue;
                }
+               found = 1;
+               break;
+       }
+       if (found) {
+               DBG("Found event %s for channel %s", name,
+                       channel->channel->name);
+               return ev;
+       } else {
+               return NULL;
        }
-
-       return NULL;
 }
 
 /*
@@ -77,7 +144,7 @@ struct ltt_kernel_event *trace_kernel_get_event_by_name(
  *
  * Return pointer to structure or NULL.
  */
-struct ltt_kernel_session *trace_kernel_create_session(char *path)
+struct ltt_kernel_session *trace_kernel_create_session(void)
 {
        struct ltt_kernel_session *lks = NULL;
 
@@ -101,33 +168,6 @@ struct ltt_kernel_session *trace_kernel_create_session(char *path)
                goto error;
        }
 
-       /*
-        * The tmp_consumer stays NULL until a set_consumer_uri command is
-        * executed. At this point, the consumer should be nullify until an
-        * enable_consumer command. This assignment is symbolic since we've zmalloc
-        * the struct.
-        */
-       lks->tmp_consumer = NULL;
-
-       if (*path != '\0') {
-               int ret;
-
-               /* Use the default consumer output which is the tracing session path. */
-               ret = snprintf(lks->consumer->dst.trace_path, PATH_MAX,
-                               "%s" DEFAULT_KERNEL_TRACE_DIR, path);
-               if (ret < 0) {
-                       PERROR("snprintf consumer trace path");
-                       goto error;
-               }
-
-               /* Set session path */
-               ret = asprintf(&lks->trace_path, "%s" DEFAULT_KERNEL_TRACE_DIR, path);
-               if (ret < 0) {
-                       PERROR("asprintf kernel traces path");
-                       goto error;
-               }
-       }
-
        return lks;
 
 error:
@@ -146,6 +186,7 @@ struct ltt_kernel_channel *trace_kernel_create_channel(
                struct lttng_channel *chan)
 {
        struct ltt_kernel_channel *lkc;
+       struct lttng_channel_extended *extended = NULL;
 
        assert(chan);
 
@@ -160,39 +201,119 @@ struct ltt_kernel_channel *trace_kernel_create_channel(
                PERROR("lttng_channel zmalloc");
                goto error;
        }
+
+       extended = zmalloc(sizeof(struct lttng_channel_extended));
+       if (!extended) {
+               PERROR("lttng_channel_channel zmalloc");
+               goto error;
+       }
        memcpy(lkc->channel, chan, sizeof(struct lttng_channel));
+       memcpy(extended, chan->attr.extended.ptr, sizeof(struct lttng_channel_extended));
+       lkc->channel->attr.extended.ptr = extended;
+       extended = NULL;
+
+       /*
+        * If we receive an empty string for channel name, it means the
+        * default channel name is requested.
+        */
+       if (chan->name[0] == '\0') {
+               strncpy(lkc->channel->name, DEFAULT_CHANNEL_NAME,
+                       sizeof(lkc->channel->name));
+       }
+       lkc->channel->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 
        lkc->fd = -1;
        lkc->stream_count = 0;
        lkc->event_count = 0;
        lkc->enabled = 1;
-       lkc->ctx = NULL;
+       lkc->published_to_notification_thread = false;
        /* Init linked list */
        CDS_INIT_LIST_HEAD(&lkc->events_list.head);
        CDS_INIT_LIST_HEAD(&lkc->stream_list.head);
+       CDS_INIT_LIST_HEAD(&lkc->ctx_list);
 
        return lkc;
 
 error:
+       if (lkc) {
+               free(lkc->channel);
+       }
+       free(extended);
+       free(lkc);
        return NULL;
 }
 
+/*
+ * Allocate and init a kernel context object.
+ *
+ * Return the allocated object or NULL on error.
+ */
+struct ltt_kernel_context *trace_kernel_create_context(
+               struct lttng_kernel_context *ctx)
+{
+       struct ltt_kernel_context *kctx;
+
+       kctx = zmalloc(sizeof(*kctx));
+       if (!kctx) {
+               PERROR("zmalloc kernel context");
+               goto error;
+       }
+
+       if (ctx) {
+               memcpy(&kctx->ctx, ctx, sizeof(kctx->ctx));
+       }
+error:
+       return kctx;
+}
+
+/*
+ * Allocate and init a kernel context object from an existing kernel context
+ * object.
+ *
+ * Return the allocated object or NULL on error.
+ */
+struct ltt_kernel_context *trace_kernel_copy_context(
+               struct ltt_kernel_context *kctx)
+{
+       struct ltt_kernel_context *kctx_copy;
+
+       assert(kctx);
+       kctx_copy = zmalloc(sizeof(*kctx_copy));
+       if (!kctx_copy) {
+               PERROR("zmalloc ltt_kernel_context");
+               goto error;
+       }
+
+       memcpy(kctx_copy, kctx, sizeof(*kctx_copy));
+       memset(&kctx_copy->list, 0, sizeof(kctx_copy->list));
+
+error:
+       return kctx_copy;
+}
+
 /*
  * Allocate and initialize a kernel event. Set name and event type.
+ * We own filter_expression, and filter.
  *
  * Return pointer to structure or NULL.
  */
-struct ltt_kernel_event *trace_kernel_create_event(struct lttng_event *ev)
+enum lttng_error_code trace_kernel_create_event(
+               struct lttng_event *ev, char *filter_expression,
+               struct lttng_filter_bytecode *filter,
+               struct ltt_kernel_event **kernel_event)
 {
-       struct ltt_kernel_event *lke;
+       enum lttng_error_code ret;
        struct lttng_kernel_event *attr;
+       struct ltt_kernel_event *local_kernel_event;
+       struct lttng_userspace_probe_location *userspace_probe_location = NULL;
 
        assert(ev);
 
-       lke = zmalloc(sizeof(struct ltt_kernel_event));
+       local_kernel_event = zmalloc(sizeof(struct ltt_kernel_event));
        attr = zmalloc(sizeof(struct lttng_kernel_event));
-       if (lke == NULL || attr == NULL) {
+       if (local_kernel_event == NULL || attr == NULL) {
                PERROR("kernel event zmalloc");
+               ret = LTTNG_ERR_NOMEM;
                goto error;
        }
 
@@ -205,11 +326,88 @@ struct ltt_kernel_event *trace_kernel_create_event(struct lttng_event *ev)
                                ev->attr.probe.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
                attr->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
                break;
+       case LTTNG_EVENT_USERSPACE_PROBE:
+       {
+               const struct lttng_userspace_probe_location* location = NULL;
+               const struct lttng_userspace_probe_location_lookup_method *lookup = NULL;
+
+               location = lttng_event_get_userspace_probe_location(ev);
+               if (!location) {
+                       ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
+                       goto error;
+               }
+
+               /*
+                * From this point on, the specific term 'uprobe' is used
+                * instead of the generic 'userspace probe' because it's the
+                * technology used at the moment for this instrumentation.
+                * LTTng currently implements userspace probes using uprobes.
+                * In the interactions with the kernel tracer, we use the
+                * uprobe term.
+                */
+               attr->instrumentation = LTTNG_KERNEL_UPROBE;
+
+               /*
+                * Only the elf lookup method is supported at the moment.
+                */
+               lookup = lttng_userspace_probe_location_get_lookup_method(
+                               location);
+               if (!lookup) {
+                       ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
+                       goto error;
+               }
+
+               /*
+                * From the kernel tracer's perspective, all userspace probe
+                * event types are all the same: a file and an offset.
+                */
+               switch (lttng_userspace_probe_location_lookup_method_get_type(lookup)) {
+               case LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_FUNCTION_ELF:
+                       /* Get the file descriptor on the target binary. */
+                       attr->u.uprobe.fd =
+                                       lttng_userspace_probe_location_function_get_binary_fd(location);
+
+                       /*
+                        * Save a reference to the probe location used during
+                        * the listing of events. Close its FD since it won't
+                        * be needed for listing.
+                        */
+                       userspace_probe_location =
+                                       lttng_userspace_probe_location_copy(location);
+                       ret = lttng_userspace_probe_location_function_set_binary_fd(
+                                       userspace_probe_location, -1);
+                       if (ret) {
+                               goto error;
+                       }
+                       break;
+               case LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_TRACEPOINT_SDT:
+                       /* Get the file descriptor on the target binary. */
+                       attr->u.uprobe.fd =
+                                       lttng_userspace_probe_location_tracepoint_get_binary_fd(location);
+
+                       /*
+                        * Save a reference to the probe location used during the listing of
+                        * events. Close its FD since it won't be needed for listing.
+                        */
+                       userspace_probe_location =
+                                       lttng_userspace_probe_location_copy(location);
+                       ret = lttng_userspace_probe_location_tracepoint_set_binary_fd(
+                                       userspace_probe_location, -1);
+                       if (ret) {
+                               goto error;
+                       }
+                       break;
+               default:
+                       DBG("Unsupported lookup method type");
+                       ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
+                       goto error;
+               }
+               break;
+       }
        case LTTNG_EVENT_FUNCTION:
                attr->instrumentation = LTTNG_KERNEL_KRETPROBE;
                attr->u.kretprobe.addr = ev->attr.probe.addr;
                attr->u.kretprobe.offset = ev->attr.probe.offset;
-               attr->u.kretprobe.offset = ev->attr.probe.offset;
                strncpy(attr->u.kretprobe.symbol_name,
                                ev->attr.probe.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
                attr->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
@@ -231,6 +429,7 @@ struct ltt_kernel_event *trace_kernel_create_event(struct lttng_event *ev)
                break;
        default:
                ERR("Unknown kernel instrumentation type (%d)", ev->type);
+               ret = LTTNG_ERR_INVALID;
                goto error;
        }
 
@@ -239,16 +438,23 @@ struct ltt_kernel_event *trace_kernel_create_event(struct lttng_event *ev)
        attr->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 
        /* Setting up a kernel event */
-       lke->fd = -1;
-       lke->event = attr;
-       lke->enabled = 1;
+       local_kernel_event->fd = -1;
+       local_kernel_event->event = attr;
+       local_kernel_event->enabled = 1;
+       local_kernel_event->filter_expression = filter_expression;
+       local_kernel_event->filter = filter;
+       local_kernel_event->userspace_probe_location = userspace_probe_location;
+
+       *kernel_event = local_kernel_event;
 
-       return lke;
+       return LTTNG_OK;
 
 error:
-       free(lke);
+       free(filter_expression);
+       free(filter);
+       free(local_kernel_event);
        free(attr);
-       return NULL;
+       return ret;
 }
 
 /*
@@ -272,8 +478,8 @@ struct ltt_kernel_metadata *trace_kernel_create_metadata(void)
        chan->attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
        chan->attr.subbuf_size = default_get_metadata_subbuf_size();
        chan->attr.num_subbuf = DEFAULT_METADATA_SUBBUF_NUM;
-       chan->attr.switch_timer_interval = DEFAULT_CHANNEL_SWITCH_TIMER;
-       chan->attr.read_timer_interval = DEFAULT_CHANNEL_READ_TIMER;
+       chan->attr.switch_timer_interval = DEFAULT_KERNEL_CHANNEL_SWITCH_TIMER;
+       chan->attr.read_timer_interval = DEFAULT_KERNEL_CHANNEL_READ_TIMER;
        chan->attr.output = DEFAULT_KERNEL_CHANNEL_OUTPUT;
 
        /* Init metadata */
@@ -309,7 +515,7 @@ struct ltt_kernel_stream *trace_kernel_create_stream(const char *name,
        }
 
        /* Set name */
-       ret = snprintf(lks->name, sizeof(lks->name), "%s_%d", name, count);
+       ret = snprintf(lks->name, sizeof(lks->name), "%s_%u", name, count);
        if (ret < 0) {
                PERROR("snprintf stream name");
                goto error;
@@ -319,6 +525,7 @@ struct ltt_kernel_stream *trace_kernel_create_stream(const char *name,
        /* Init stream */
        lks->fd = -1;
        lks->state = 0;
+       lks->cpu = count;
 
        return lks;
 
@@ -372,10 +579,26 @@ void trace_kernel_destroy_event(struct ltt_kernel_event *event)
        /* Remove from event list */
        cds_list_del(&event->list);
 
+       free(event->filter_expression);
+       free(event->filter);
+
        free(event->event);
        free(event);
 }
 
+/*
+ * Cleanup kernel context structure.
+ */
+void trace_kernel_destroy_context(struct ltt_kernel_context *ctx)
+{
+       assert(ctx);
+
+       if (ctx->in_list) {
+               cds_list_del(&ctx->list);
+       }
+       free(ctx);
+}
+
 /*
  * Cleanup kernel channel structure.
  */
@@ -383,7 +606,9 @@ void trace_kernel_destroy_channel(struct ltt_kernel_channel *channel)
 {
        struct ltt_kernel_stream *stream, *stmp;
        struct ltt_kernel_event *event, *etmp;
+       struct ltt_kernel_context *ctx, *ctmp;
        int ret;
+       enum lttng_error_code status;
 
        assert(channel);
 
@@ -406,11 +631,23 @@ void trace_kernel_destroy_channel(struct ltt_kernel_channel *channel)
                trace_kernel_destroy_event(event);
        }
 
+       /* For each context in the channel list */
+       cds_list_for_each_entry_safe(ctx, ctmp, &channel->ctx_list, list) {
+               trace_kernel_destroy_context(ctx);
+       }
+
        /* Remove from channel list */
        cds_list_del(&channel->list);
 
+       if (notification_thread_handle
+                       && channel->published_to_notification_thread) {
+               status = notification_thread_command_remove_channel(
+                               notification_thread_handle,
+                               channel->key, LTTNG_DOMAIN_KERNEL);
+               assert(status == LTTNG_OK);
+       }
+       free(channel->channel->attr.extended.ptr);
        free(channel->channel);
-       free(channel->ctx);
        free(channel);
 }
 
@@ -438,6 +675,8 @@ void trace_kernel_destroy_metadata(struct ltt_kernel_metadata *metadata)
 
 /*
  * Cleanup kernel session structure
+ *
+ * Should *NOT* be called with RCU read-side lock held.
  */
 void trace_kernel_destroy_session(struct ltt_kernel_session *session)
 {
@@ -472,9 +711,7 @@ void trace_kernel_destroy_session(struct ltt_kernel_session *session)
        }
 
        /* Wipe consumer output object */
-       consumer_destroy_output(session->consumer);
-       consumer_destroy_output(session->tmp_consumer);
+       consumer_output_put(session->consumer);
 
-       free(session->trace_path);
        free(session);
 }
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