Fix: relayd: file rotation and live read

[lttng-tools.git] / src / bin / lttng-relayd / tracefile-array.c

diff --git a/src/bin/lttng-relayd/tracefile-array.c b/src/bin/lttng-relayd/tracefile-array.c
new file mode 100644 (file)
index 0000000..bcbee5c
--- /dev/null
+++ b/src/bin/lttng-relayd/tracefile-array.c
@@ -0,0 +1,161 @@
+/*
+ * Copyright (C) 2015 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License, version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This program 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 General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 51
+ * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#define _GNU_SOURCE
+#define _LGPL_SOURCE
+#include <assert.h>
+#include <common/common.h>
+#include <common/utils.h>
+#include <common/defaults.h>
+
+#include "tracefile-array.h"
+
+struct tracefile_array *tracefile_array_create(size_t count)
+{
+       struct tracefile_array *tfa = NULL;
+       int i;
+
+       tfa = zmalloc(sizeof(*tfa));
+       if (!tfa) {
+               goto error;
+       }
+       tfa->tf = zmalloc(sizeof(*tfa->tf) * count);
+       if (!tfa->tf) {
+               goto error;
+       }
+       tfa->count = count;
+       for (i = 0; i < count; i++) {
+               tfa->tf[i].seq_head = -1ULL;
+               tfa->tf[i].seq_tail = -1ULL;
+       }
+       tfa->seq_head = -1ULL;
+       tfa->seq_tail = -1ULL;
+       return tfa;
+
+error:
+       if (tfa) {
+               free(tfa->tf);
+       }
+       free(tfa);
+       return NULL;
+}
+
+void tracefile_array_destroy(struct tracefile_array *tfa)
+{
+       if (!tfa) {
+               return;
+       }
+       free(tfa->tf);
+       free(tfa);
+}
+
+void tracefile_array_file_rotate(struct tracefile_array *tfa)
+{
+       uint64_t *headp, *tailp;
+
+       if (!tfa->count) {
+               /* Not in tracefile rotation mode. */
+               return;
+       }
+       /* Rotate to next file.  */
+       tfa->file_head = (tfa->file_head + 1) % tfa->count;
+       if (tfa->file_head == tfa->file_tail) {
+               /* Move tail. */
+               tfa->file_tail = (tfa->file_tail + 1) % tfa->count;
+       }
+       headp = &tfa->tf[tfa->file_head].seq_head;
+       tailp = &tfa->tf[tfa->file_head].seq_tail;
+       /*
+        * If we overwrite a file with content, we need to push the tail
+        * to the position following the content we are overwriting.
+        */
+       if (*headp != -1ULL) {
+               tfa->seq_tail = tfa->tf[tfa->file_tail].seq_tail;
+       }
+       /* Reset this file head/tail (overwrite). */
+       *headp = -1ULL;
+       *tailp = -1ULL;
+}
+
+void tracefile_array_commit_seq(struct tracefile_array *tfa)
+{
+       uint64_t *headp, *tailp;
+
+       /* Increment overall head. */
+       tfa->seq_head++;
+       /* If we are committing our first index overall, set tail to 0. */
+       if (tfa->seq_tail == -1ULL) {
+               tfa->seq_tail = 0;
+       }
+       if (!tfa->count) {
+               /* Not in tracefile rotation mode. */
+               return;
+       }
+       headp = &tfa->tf[tfa->file_head].seq_head;
+       tailp = &tfa->tf[tfa->file_head].seq_tail;
+       /* Update head tracefile seq_head. */
+       *headp = tfa->seq_head;
+       /*
+        * If we are committing our first index in this packet, set tail
+        * to this index seq count.
+        */
+       if (*tailp == -1ULL) {
+               *tailp = tfa->seq_head;
+       }
+}
+
+uint64_t tracefile_array_get_file_index_head(struct tracefile_array *tfa)
+{
+       return tfa->file_head;
+}
+
+uint64_t tracefile_array_get_seq_head(struct tracefile_array *tfa)
+{
+       return tfa->seq_head;
+}
+
+uint64_t tracefile_array_get_file_index_tail(struct tracefile_array *tfa)
+{
+       return tfa->file_tail;
+}
+
+uint64_t tracefile_array_get_seq_tail(struct tracefile_array *tfa)
+{
+       return tfa->seq_tail;
+}
+
+bool tracefile_array_seq_in_file(struct tracefile_array *tfa,
+               uint64_t file_index, uint64_t seq)
+{
+       if (!tfa->count) {
+               /*
+                * Not in tracefile rotation mode; we are guaranteed to have the
+                * index in this file.
+                */
+               return true;
+       }
+       assert(file_index < tfa->count);
+       if (seq == -1ULL) {
+               return false;
+       }
+       if (seq >= tfa->tf[file_index].seq_tail
+                       && seq <= tfa->tf[file_index].seq_head) {
+               return true;
+       } else {
+               return false;
+       }
+}