#include <common/sessiond-comm/sessiond-comm.h>
#include <common/uri.h>
#include <common/utils.h>
+#include <common/dynamic-buffer.h>
#include <lttng/lttng.h>
#include <lttng/health-internal.h>
#include <lttng/trigger/trigger-internal.h>
#include <lttng/endpoint.h>
#include <lttng/channel-internal.h>
+#include <lttng/event-internal.h>
#include "filter/filter-ast.h"
#include "filter/filter-parser.h"
struct lttcomm_event_command_header *cmd_header = NULL;
size_t cmd_header_len;
uint32_t nb_events, i;
- void *extended_at;
+ void *comm_ext_at;
+ void *listing_at;
+ char *reception_buffer = NULL;
+ char *listing = NULL;
+ size_t storage_req;
/* Safety check. An handle and channel name are mandatory */
if (handle == NULL || channel_name == NULL) {
lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
ret = lttng_ctl_ask_sessiond_fds_varlen(&lsm, NULL, 0, NULL, 0,
- (void **) events, (void **) &cmd_header, &cmd_header_len);
+ (void **) &reception_buffer, (void **) &cmd_header,
+ &cmd_header_len);
if (ret < 0) {
- goto error;
+ goto end;
}
/* Set number of events and free command header */
nb_events = cmd_header->nb_events;
if (nb_events > INT_MAX) {
ret = -EOVERFLOW;
- goto error;
+ goto end;
}
- ret = (int) nb_events;
free(cmd_header);
cmd_header = NULL;
- /* Set extended info pointers */
- extended_at = ((void*) (*events)) +
- nb_events * sizeof(struct lttng_event);
+ /*
+ * The buffer that is returned must contain a "flat" version of
+ * the events that are returned. In other words, all pointers
+ * within an lttng_event must point to a location within the returned
+ * buffer so that the user may free by simply calling free() on the
+ * returned buffer. This is needed in order to maintain API
+ * compatibility.
+ *
+ * A first pass is performed to figure the size of the buffer that
+ * must be returned. A second pass is then performed to setup
+ * the returned events so that their members always point within the
+ * buffer.
+ *
+ * The layout of the returned buffer is as follows:
+ * - struct lttng_event[nb_events],
+ * - nb_events times the following:
+ * - struct lttng_event_extended,
+ * - flattened version of userspace_probe_location
+ * - filter_expression
+ * - exclusions
+ * - padding to align to 64-bits
+ */
+ comm_ext_at = reception_buffer +
+ (nb_events * sizeof(struct lttng_event));
+ storage_req = nb_events * sizeof(struct lttng_event);
for (i = 0; i < nb_events; i++) {
- struct lttcomm_event_extended_header *ext_header;
- struct lttng_event *event = &(*events)[i];
+ struct lttcomm_event_extended_header *ext_comm =
+ (struct lttcomm_event_extended_header *) comm_ext_at;
- event->extended.ptr = extended_at;
- ext_header =
- (struct lttcomm_event_extended_header *) extended_at;
- extended_at += sizeof(*ext_header);
- extended_at += ext_header->filter_len;
- extended_at +=
- ext_header->nb_exclusions * LTTNG_SYMBOL_NAME_LEN;
+ comm_ext_at += sizeof(*ext_comm);
+ comm_ext_at += ext_comm->filter_len;
+ comm_ext_at +=
+ ext_comm->nb_exclusions * LTTNG_SYMBOL_NAME_LEN;
+
+ storage_req += sizeof(struct lttng_event_extended);
+ /* TODO: missing size of flat userspace probe. */
+ storage_req += ext_comm->filter_len;
+ storage_req += ext_comm->nb_exclusions * LTTNG_SYMBOL_NAME_LEN;
+ storage_req += storage_req % 8;
}
- return ret;
-error:
+ listing = zmalloc(storage_req);
+ if (!listing) {
+ goto end;
+ }
+ memcpy(listing, reception_buffer,
+ nb_events * sizeof(struct lttng_event));
+
+ comm_ext_at = reception_buffer +
+ (nb_events * sizeof(struct lttng_event));
+ listing_at = listing +
+ (nb_events * sizeof(struct lttng_event));
+ for (i = 0; i < nb_events; i++) {
+ struct lttng_event *event = (struct lttng_event *)
+ (listing + (sizeof(struct lttng_event) * i));
+ struct lttcomm_event_extended_header *ext_comm =
+ (struct lttcomm_event_extended_header *) comm_ext_at;
+ struct lttng_event_extended *event_extended =
+ (struct lttng_event_extended *) listing_at;
+
+ event->extended.ptr = event_extended;
+ listing_at += sizeof(*event_extended);
+ comm_ext_at += sizeof(*ext_comm);
+
+ /* Copy filter expression. */
+ memcpy(listing_at, comm_ext_at, ext_comm->filter_len);
+ event_extended->filter_expression = listing_at;
+ comm_ext_at += ext_comm->filter_len;
+ listing_at += ext_comm->filter_len;
+
+ /* Copy exclusions. */
+ event_extended->exclusions.count = ext_comm->nb_exclusions;
+ event_extended->exclusions.strings = listing_at;
+ memcpy(listing_at, comm_ext_at,
+ ext_comm->nb_exclusions * LTTNG_SYMBOL_NAME_LEN);
+ listing_at += ext_comm->nb_exclusions * LTTNG_SYMBOL_NAME_LEN;
+ comm_ext_at += ext_comm->nb_exclusions * LTTNG_SYMBOL_NAME_LEN;
+
+ listing_at += ((uintptr_t) listing_at) % 8;
+ }
+
+ *events = (struct lttng_event *) listing;
+ listing = NULL;
+ ret = (int) nb_events;
+end:
free(cmd_header);
- free(*events);
+ free(reception_buffer);
+ free(listing);
return ret;
}
projects / lttng-tools.git / blobdiff