Version 2.4.4

[lttng-modules.git] / lttng-context.c

diff --git a/lttng-context.c b/lttng-context.c
index a28a9d2370ae39e3bbd569d2de416f6924e0678c..b79b7f667bf483ce6611cfae31190fb1c19f12b4 100644 (file)
--- a/lttng-context.c
+++ b/lttng-context.c
@@ -1,11 +1,23 @@
 /*
  * lttng-context.c
  *
- * Copyright 2011 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- *
  * LTTng trace/channel/event context management.
  *
- * Dual LGPL v2.1/GPL v2 license.
+ * Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; only
+ * version 2.1 of the License.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 #include <linux/module.h>
@@ -43,6 +55,7 @@ struct lttng_ctx_field *lttng_append_context(struct lttng_ctx **ctx_p)
                *ctx_p = kzalloc(sizeof(struct lttng_ctx), GFP_KERNEL);
                if (!*ctx_p)
                        return NULL;
+               (*ctx_p)->largest_align = 1;
        }
        ctx = *ctx_p;
        if (ctx->nr_fields + 1 > ctx->allocated_fields) {
@@ -63,6 +76,94 @@ struct lttng_ctx_field *lttng_append_context(struct lttng_ctx **ctx_p)
 }
 EXPORT_SYMBOL_GPL(lttng_append_context);
 
+/*
+ * lttng_context_update() should be called at least once between context
+ * modification and trace start.
+ */
+void lttng_context_update(struct lttng_ctx *ctx)
+{
+       int i;
+       size_t largest_align = 8;       /* in bits */
+
+       for (i = 0; i < ctx->nr_fields; i++) {
+               struct lttng_type *type;
+               size_t field_align = 8;
+
+               type = &ctx->fields[i].event_field.type;
+               switch (type->atype) {
+               case atype_integer:
+                       field_align = type->u.basic.integer.alignment;
+                       break;
+               case atype_array:
+               {
+                       struct lttng_basic_type *btype;
+
+                       btype = &type->u.array.elem_type;
+                       switch (btype->atype) {
+                       case atype_integer:
+                               field_align = btype->u.basic.integer.alignment;
+                               break;
+                       case atype_string:
+                               break;
+
+                       case atype_array:
+                       case atype_sequence:
+                       default:
+                               WARN_ON_ONCE(1);
+                               break;
+                       }
+                       break;
+               }
+               case atype_sequence:
+               {
+                       struct lttng_basic_type *btype;
+
+                       btype = &type->u.sequence.length_type;
+                       switch (btype->atype) {
+                       case atype_integer:
+                               field_align = btype->u.basic.integer.alignment;
+                               break;
+
+                       case atype_string:
+                       case atype_array:
+                       case atype_sequence:
+                       default:
+                               WARN_ON_ONCE(1);
+                               break;
+                       }
+
+                       btype = &type->u.sequence.elem_type;
+                       switch (btype->atype) {
+                       case atype_integer:
+                               field_align = max_t(size_t,
+                                       field_align,
+                                       btype->u.basic.integer.alignment);
+                               break;
+
+                       case atype_string:
+                               break;
+
+                       case atype_array:
+                       case atype_sequence:
+                       default:
+                               WARN_ON_ONCE(1);
+                               break;
+                       }
+                       break;
+               }
+               case atype_string:
+                       break;
+
+               case atype_enum:
+               default:
+                       WARN_ON_ONCE(1);
+                       break;
+               }
+               largest_align = max_t(size_t, largest_align, field_align);
+       }
+       ctx->largest_align = largest_align >> 3;        /* bits to bytes */
+}
+
 /*
  * Remove last context field.
  */