--- /dev/null
+#ifndef _LTTNG_FILTER_H
+#define _LTTNG_FILTER_H
+
+/*
+ * lttng-filter.h
+ *
+ * LTTng modules filter header.
+ *
+ * Copyright (C) 2010-2014 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/kernel.h>
+
+#include "lttng-events.h"
+#include "filter-bytecode.h"
+
+/* Filter stack length, in number of entries */
+#define FILTER_STACK_LEN 10 /* includes 2 dummy */
+#define FILTER_STACK_EMPTY 1
+
+#ifdef DEBUG
+#define dbg_printk(fmt, args...) \
+ printk(KERN_DEBUG "[debug bytecode in %s:%s@%u] " fmt, \
+ __FILE__, __func__, __LINE__, ## args)
+#else
+#define dbg_printk(fmt, args...) \
+do { \
+ /* do nothing but check printf format */ \
+ if (0) \
+ printk(KERN_DEBUG "[debug bytecode in %s:%s@%u] " fmt, \
+ __FILE__, __func__, __LINE__, ## args); \
+} while (0)
+#endif
+
+/* Linked bytecode. Child of struct lttng_bytecode_runtime. */
+struct bytecode_runtime {
+ struct lttng_bytecode_runtime p;
+ uint16_t len;
+ char data[0];
+};
+
+enum entry_type {
+ REG_S64,
+ REG_DOUBLE,
+ REG_STRING,
+ REG_TYPE_UNKNOWN,
+};
+
+/* Validation stack */
+struct vstack_entry {
+ enum entry_type type;
+};
+
+struct vstack {
+ int top; /* top of stack */
+ struct vstack_entry e[FILTER_STACK_LEN];
+};
+
+static inline
+void vstack_init(struct vstack *stack)
+{
+ stack->top = -1;
+}
+
+static inline
+struct vstack_entry *vstack_ax(struct vstack *stack)
+{
+ if (unlikely(stack->top < 0))
+ return NULL;
+ return &stack->e[stack->top];
+}
+
+static inline
+struct vstack_entry *vstack_bx(struct vstack *stack)
+{
+ if (unlikely(stack->top < 1))
+ return NULL;
+ return &stack->e[stack->top - 1];
+}
+
+static inline
+int vstack_push(struct vstack *stack)
+{
+ if (stack->top >= FILTER_STACK_LEN - 1) {
+ printk(KERN_WARNING "Stack full\n");
+ return -EINVAL;
+ }
+ ++stack->top;
+ return 0;
+}
+
+static inline
+int vstack_pop(struct vstack *stack)
+{
+ if (unlikely(stack->top < 0)) {
+ printk(KERN_WARNING "Stack empty\n");
+ return -EINVAL;
+ }
+ stack->top--;
+ return 0;
+}
+
+/* Execution stack */
+struct estack_entry {
+ union {
+ int64_t v;
+
+ struct {
+ const char *str;
+ size_t seq_len;
+ int literal; /* is string literal ? */
+ } s;
+ } u;
+};
+
+struct estack {
+ int top; /* top of stack */
+ struct estack_entry e[FILTER_STACK_LEN];
+};
+
+#define estack_ax_v ax
+#define estack_bx_v bx
+
+#define estack_ax(stack, top) \
+ ({ \
+ WARN_ON_ONCE((top) <= FILTER_STACK_EMPTY); \
+ &(stack)->e[top]; \
+ })
+
+#define estack_bx(stack, top) \
+ ({ \
+ WARN_ON_ONCE((top) <= FILTER_STACK_EMPTY + 1); \
+ &(stack)->e[(top) - 1]; \
+ })
+
+#define estack_push(stack, top, ax, bx) \
+ do { \
+ WARN_ON_ONCE((top) >= FILTER_STACK_LEN - 1); \
+ (stack)->e[(top) - 1].u.v = (bx); \
+ (bx) = (ax); \
+ ++(top); \
+ } while (0)
+
+#define estack_pop(stack, top, ax, bx) \
+ do { \
+ WARN_ON_ONCE((top) <= FILTER_STACK_EMPTY); \
+ (ax) = (bx); \
+ (bx) = (stack)->e[(top) - 2].u.v; \
+ (top)--; \
+ } while (0)
+
+const char *lttng_filter_print_op(enum filter_op op);
+
+int lttng_filter_validate_bytecode(struct bytecode_runtime *bytecode);
+int lttng_filter_specialize_bytecode(struct bytecode_runtime *bytecode);
+
+uint64_t lttng_filter_false(void *filter_data,
+ const char *filter_stack_data);
+uint64_t lttng_filter_interpret_bytecode(void *filter_data,
+ const char *filter_stack_data);
+
+#endif /* _LTTNG_FILTER_H */