Implement filtering infrastructure

[lttng-modules.git] / lttng-filter.h

diff --git a/lttng-filter.h b/lttng-filter.h
new file mode 100644 (file)
index 0000000..98b97c2
--- /dev/null
+++ b/lttng-filter.h
@@ -0,0 +1,176 @@
+#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 */