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

/*
 * lttng-filter.c
 *
 * LTTng modules filter code.
 *
 * 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/list.h>
#include <linux/slab.h>

#include "lttng-filter.h"

static const char *opnames[] = {
	[ FILTER_OP_UNKNOWN ] = "UNKNOWN",

	[ FILTER_OP_RETURN ] = "RETURN",

	/* binary */
	[ FILTER_OP_MUL ] = "MUL",
	[ FILTER_OP_DIV ] = "DIV",
	[ FILTER_OP_MOD ] = "MOD",
	[ FILTER_OP_PLUS ] = "PLUS",
	[ FILTER_OP_MINUS ] = "MINUS",
	[ FILTER_OP_RSHIFT ] = "RSHIFT",
	[ FILTER_OP_LSHIFT ] = "LSHIFT",
	[ FILTER_OP_BIN_AND ] = "BIN_AND",
	[ FILTER_OP_BIN_OR ] = "BIN_OR",
	[ FILTER_OP_BIN_XOR ] = "BIN_XOR",

	/* binary comparators */
	[ FILTER_OP_EQ ] = "EQ",
	[ FILTER_OP_NE ] = "NE",
	[ FILTER_OP_GT ] = "GT",
	[ FILTER_OP_LT ] = "LT",
	[ FILTER_OP_GE ] = "GE",
	[ FILTER_OP_LE ] = "LE",

	/* string binary comparators */
	[ FILTER_OP_EQ_STRING ] = "EQ_STRING",
	[ FILTER_OP_NE_STRING ] = "NE_STRING",
	[ FILTER_OP_GT_STRING ] = "GT_STRING",
	[ FILTER_OP_LT_STRING ] = "LT_STRING",
	[ FILTER_OP_GE_STRING ] = "GE_STRING",
	[ FILTER_OP_LE_STRING ] = "LE_STRING",

	/* s64 binary comparators */
	[ FILTER_OP_EQ_S64 ] = "EQ_S64",
	[ FILTER_OP_NE_S64 ] = "NE_S64",
	[ FILTER_OP_GT_S64 ] = "GT_S64",
	[ FILTER_OP_LT_S64 ] = "LT_S64",
	[ FILTER_OP_GE_S64 ] = "GE_S64",
	[ FILTER_OP_LE_S64 ] = "LE_S64",

	/* double binary comparators */
	[ FILTER_OP_EQ_DOUBLE ] = "EQ_DOUBLE",
	[ FILTER_OP_NE_DOUBLE ] = "NE_DOUBLE",
	[ FILTER_OP_GT_DOUBLE ] = "GT_DOUBLE",
	[ FILTER_OP_LT_DOUBLE ] = "LT_DOUBLE",
	[ FILTER_OP_GE_DOUBLE ] = "GE_DOUBLE",
	[ FILTER_OP_LE_DOUBLE ] = "LE_DOUBLE",

	/* Mixed S64-double binary comparators */
	[ FILTER_OP_EQ_DOUBLE_S64 ] = "EQ_DOUBLE_S64",
	[ FILTER_OP_NE_DOUBLE_S64 ] = "NE_DOUBLE_S64",
	[ FILTER_OP_GT_DOUBLE_S64 ] = "GT_DOUBLE_S64",
	[ FILTER_OP_LT_DOUBLE_S64 ] = "LT_DOUBLE_S64",
	[ FILTER_OP_GE_DOUBLE_S64 ] = "GE_DOUBLE_S64",
	[ FILTER_OP_LE_DOUBLE_S64 ] = "LE_DOUBLE_S64",

	[ FILTER_OP_EQ_S64_DOUBLE ] = "EQ_S64_DOUBLE",
	[ FILTER_OP_NE_S64_DOUBLE ] = "NE_S64_DOUBLE",
	[ FILTER_OP_GT_S64_DOUBLE ] = "GT_S64_DOUBLE",
	[ FILTER_OP_LT_S64_DOUBLE ] = "LT_S64_DOUBLE",
	[ FILTER_OP_GE_S64_DOUBLE ] = "GE_S64_DOUBLE",
	[ FILTER_OP_LE_S64_DOUBLE ] = "LE_S64_DOUBLE",

	/* unary */
	[ FILTER_OP_UNARY_PLUS ] = "UNARY_PLUS",
	[ FILTER_OP_UNARY_MINUS ] = "UNARY_MINUS",
	[ FILTER_OP_UNARY_NOT ] = "UNARY_NOT",
	[ FILTER_OP_UNARY_PLUS_S64 ] = "UNARY_PLUS_S64",
	[ FILTER_OP_UNARY_MINUS_S64 ] = "UNARY_MINUS_S64",
	[ FILTER_OP_UNARY_NOT_S64 ] = "UNARY_NOT_S64",
	[ FILTER_OP_UNARY_PLUS_DOUBLE ] = "UNARY_PLUS_DOUBLE",
	[ FILTER_OP_UNARY_MINUS_DOUBLE ] = "UNARY_MINUS_DOUBLE",
	[ FILTER_OP_UNARY_NOT_DOUBLE ] = "UNARY_NOT_DOUBLE",

	/* logical */
	[ FILTER_OP_AND ] = "AND",
	[ FILTER_OP_OR ] = "OR",

	/* load field ref */
	[ FILTER_OP_LOAD_FIELD_REF ] = "LOAD_FIELD_REF",
	[ FILTER_OP_LOAD_FIELD_REF_STRING ] = "LOAD_FIELD_REF_STRING",
	[ FILTER_OP_LOAD_FIELD_REF_SEQUENCE ] = "LOAD_FIELD_REF_SEQUENCE",
	[ FILTER_OP_LOAD_FIELD_REF_S64 ] = "LOAD_FIELD_REF_S64",
	[ FILTER_OP_LOAD_FIELD_REF_DOUBLE ] = "LOAD_FIELD_REF_DOUBLE",

	/* load from immediate operand */
	[ FILTER_OP_LOAD_STRING ] = "LOAD_STRING",
	[ FILTER_OP_LOAD_S64 ] = "LOAD_S64",
	[ FILTER_OP_LOAD_DOUBLE ] = "LOAD_DOUBLE",

	/* cast */
	[ FILTER_OP_CAST_TO_S64 ] = "CAST_TO_S64",
	[ FILTER_OP_CAST_DOUBLE_TO_S64 ] = "CAST_DOUBLE_TO_S64",
	[ FILTER_OP_CAST_NOP ] = "CAST_NOP",

	/* get context ref */
	[ FILTER_OP_GET_CONTEXT_REF ] = "GET_CONTEXT_REF",
	[ FILTER_OP_GET_CONTEXT_REF_STRING ] = "GET_CONTEXT_REF_STRING",
	[ FILTER_OP_GET_CONTEXT_REF_S64 ] = "GET_CONTEXT_REF_S64",
	[ FILTER_OP_GET_CONTEXT_REF_DOUBLE ] = "GET_CONTEXT_REF_DOUBLE",

	/* load userspace field ref */
	[ FILTER_OP_LOAD_FIELD_REF_USER_STRING ] = "LOAD_FIELD_REF_USER_STRING",
	[ FILTER_OP_LOAD_FIELD_REF_USER_SEQUENCE ] = "LOAD_FIELD_REF_USER_SEQUENCE",
};

const char *lttng_filter_print_op(enum filter_op op)
{
	if (op >= NR_FILTER_OPS)
		return "UNKNOWN";
	else
		return opnames[op];
}

static
int apply_field_reloc(struct lttng_event *event,
		struct bytecode_runtime *runtime,
		uint32_t runtime_len,
		uint32_t reloc_offset,
		const char *field_name)
{
	const struct lttng_event_desc *desc;
	const struct lttng_event_field *fields, *field = NULL;
	unsigned int nr_fields, i;
	struct field_ref *field_ref;
	struct load_op *op;
	uint32_t field_offset = 0;

	dbg_printk("Apply field reloc: %u %s\n", reloc_offset, field_name);

	/* Lookup event by name */
	desc = event->desc;
	if (!desc)
		return -EINVAL;
	fields = desc->fields;
	if (!fields)
		return -EINVAL;
	nr_fields = desc->nr_fields;
	for (i = 0; i < nr_fields; i++) {
		if (!strcmp(fields[i].name, field_name)) {
			field = &fields[i];
			break;
		}
		/* compute field offset */
		switch (fields[i].type.atype) {
		case atype_integer:
		case atype_enum:
			field_offset += sizeof(int64_t);
			break;
		case atype_array:
		case atype_sequence:
			field_offset += sizeof(unsigned long);
			field_offset += sizeof(void *);
			break;
		case atype_string:
			field_offset += sizeof(void *);
			break;
		default:
			return -EINVAL;
		}
	}
	if (!field)
		return -EINVAL;

	/* Check if field offset is too large for 16-bit offset */
	if (field_offset > LTTNG_KERNEL_FILTER_BYTECODE_MAX_LEN - 1)
		return -EINVAL;

	/* set type */
	op = (struct load_op *) &runtime->data[reloc_offset];
	field_ref = (struct field_ref *) op->data;
	switch (field->type.atype) {
	case atype_integer:
	case atype_enum:
		op->op = FILTER_OP_LOAD_FIELD_REF_S64;
		break;
	case atype_array:
	case atype_sequence:
		if (field->user)
			op->op = FILTER_OP_LOAD_FIELD_REF_USER_SEQUENCE;
		else
			op->op = FILTER_OP_LOAD_FIELD_REF_SEQUENCE;
		break;
	case atype_string:
		if (field->user)
			op->op = FILTER_OP_LOAD_FIELD_REF_USER_STRING;
		else
			op->op = FILTER_OP_LOAD_FIELD_REF_STRING;
		break;
	default:
		return -EINVAL;
	}
	/* set offset */
	field_ref->offset = (uint16_t) field_offset;
	return 0;
}

static
int apply_context_reloc(struct lttng_event *event,
		struct bytecode_runtime *runtime,
		uint32_t runtime_len,
		uint32_t reloc_offset,
		const char *context_name)
{
	struct field_ref *field_ref;
	struct load_op *op;
	struct lttng_ctx_field *ctx_field;
	int idx;

	dbg_printk("Apply context reloc: %u %s\n", reloc_offset, context_name);

	/* Get context index */
	idx = lttng_get_context_index(lttng_static_ctx, context_name);
	if (idx < 0)
		return -ENOENT;

	/* Check if idx is too large for 16-bit offset */
	if (idx > LTTNG_KERNEL_FILTER_BYTECODE_MAX_LEN - 1)
		return -EINVAL;

	/* Get context return type */
	ctx_field = &lttng_static_ctx->fields[idx];
	op = (struct load_op *) &runtime->data[reloc_offset];
	field_ref = (struct field_ref *) op->data;
	switch (ctx_field->event_field.type.atype) {
	case atype_integer:
	case atype_enum:
		op->op = FILTER_OP_GET_CONTEXT_REF_S64;
		break;
		/* Sequence and array supported as string */
	case atype_string:
	case atype_array:
	case atype_sequence:
		BUG_ON(ctx_field->event_field.user);
		op->op = FILTER_OP_GET_CONTEXT_REF_STRING;
		break;
	default:
		return -EINVAL;
	}
	/* set offset to context index within channel contexts */
	field_ref->offset = (uint16_t) idx;
	return 0;
}

static
int apply_reloc(struct lttng_event *event,
		struct bytecode_runtime *runtime,
		uint32_t runtime_len,
		uint32_t reloc_offset,
		const char *name)
{
	struct load_op *op;

	dbg_printk("Apply reloc: %u %s\n", reloc_offset, name);

	/* Ensure that the reloc is within the code */
	if (runtime_len - reloc_offset < sizeof(uint16_t))
		return -EINVAL;

	op = (struct load_op *) &runtime->data[reloc_offset];
	switch (op->op) {
	case FILTER_OP_LOAD_FIELD_REF:
		return apply_field_reloc(event, runtime, runtime_len,
			reloc_offset, name);
	case FILTER_OP_GET_CONTEXT_REF:
		return apply_context_reloc(event, runtime, runtime_len,
			reloc_offset, name);
	default:
		printk(KERN_WARNING "Unknown reloc op type %u\n", op->op);
		return -EINVAL;
	}
	return 0;
}

static
int bytecode_is_linked(struct lttng_filter_bytecode_node *filter_bytecode,
		struct lttng_event *event)
{
	struct lttng_bytecode_runtime *bc_runtime;

	list_for_each_entry(bc_runtime,
			&event->bytecode_runtime_head, node) {
		if (bc_runtime->bc == filter_bytecode)
			return 1;
	}
	return 0;
}

/*
 * Take a bytecode with reloc table and link it to an event to create a
 * bytecode runtime.
 */
static
int _lttng_filter_event_link_bytecode(struct lttng_event *event,
		struct lttng_filter_bytecode_node *filter_bytecode,
		struct list_head *insert_loc)
{
	int ret, offset, next_offset;
	struct bytecode_runtime *runtime = NULL;
	size_t runtime_alloc_len;

	if (!filter_bytecode)
		return 0;
	/* Bytecode already linked */
	if (bytecode_is_linked(filter_bytecode, event))
		return 0;

	dbg_printk("Linking...\n");

	/* We don't need the reloc table in the runtime */
	runtime_alloc_len = sizeof(*runtime) + filter_bytecode->bc.reloc_offset;
	runtime = kzalloc(runtime_alloc_len, GFP_KERNEL);
	if (!runtime) {
		ret = -ENOMEM;
		goto alloc_error;
	}
	runtime->p.bc = filter_bytecode;
	runtime->len = filter_bytecode->bc.reloc_offset;
	/* copy original bytecode */
	memcpy(runtime->data, filter_bytecode->bc.data, runtime->len);
	/*
	 * apply relocs. Those are a uint16_t (offset in bytecode)
	 * followed by a string (field name).
	 */
	for (offset = filter_bytecode->bc.reloc_offset;
			offset < filter_bytecode->bc.len;
			offset = next_offset) {
		uint16_t reloc_offset =
			*(uint16_t *) &filter_bytecode->bc.data[offset];
		const char *name =
			(const char *) &filter_bytecode->bc.data[offset + sizeof(uint16_t)];

		ret = apply_reloc(event, runtime, runtime->len, reloc_offset, name);
		if (ret) {
			goto link_error;
		}
		next_offset = offset + sizeof(uint16_t) + strlen(name) + 1;
	}
	/* Validate bytecode */
	ret = lttng_filter_validate_bytecode(runtime);
	if (ret) {
		goto link_error;
	}
	/* Specialize bytecode */
	ret = lttng_filter_specialize_bytecode(runtime);
	if (ret) {
		goto link_error;
	}
	runtime->p.filter = lttng_filter_interpret_bytecode;
	runtime->p.link_failed = 0;
	list_add_rcu(&runtime->p.node, insert_loc);
	dbg_printk("Linking successful.\n");
	return 0;

link_error:
	runtime->p.filter = lttng_filter_false;
	runtime->p.link_failed = 1;
	list_add_rcu(&runtime->p.node, insert_loc);
alloc_error:
	dbg_printk("Linking failed.\n");
	return ret;
}

void lttng_filter_sync_state(struct lttng_bytecode_runtime *runtime)
{
	struct lttng_filter_bytecode_node *bc = runtime->bc;

	if (!bc->enabler->enabled || runtime->link_failed)
		runtime->filter = lttng_filter_false;
	else
		runtime->filter = lttng_filter_interpret_bytecode;
}

/*
 * Link bytecode for all enablers referenced by an event.
 */
void lttng_enabler_event_link_bytecode(struct lttng_event *event,
		struct lttng_enabler *enabler)
{
	struct lttng_filter_bytecode_node *bc;
	struct lttng_bytecode_runtime *runtime;

	/* Can only be called for events with desc attached */
	WARN_ON_ONCE(!event->desc);

	/* Link each bytecode. */
	list_for_each_entry(bc, &enabler->filter_bytecode_head, node) {
		int found = 0, ret;
		struct list_head *insert_loc;

		list_for_each_entry(runtime,
				&event->bytecode_runtime_head, node) {
			if (runtime->bc == bc) {
				found = 1;
				break;
			}
		}
		/* Skip bytecode already linked */
		if (found)
			continue;

		/*
		 * Insert at specified priority (seqnum) in increasing
		 * order.
		 */
		list_for_each_entry_reverse(runtime,
				&event->bytecode_runtime_head, node) {
			if (runtime->bc->bc.seqnum < bc->bc.seqnum) {
				/* insert here */
				insert_loc = &runtime->node;
				goto add_within;
			}
		}
		/* Add to head to list */
		insert_loc = &event->bytecode_runtime_head;
	add_within:
		dbg_printk("linking bytecode\n");
		ret = _lttng_filter_event_link_bytecode(event, bc,
				insert_loc);
		if (ret) {
			dbg_printk("[lttng filter] warning: cannot link event bytecode\n");
		}
	}
}

/*
 * We own the filter_bytecode if we return success.
 */
int lttng_filter_enabler_attach_bytecode(struct lttng_enabler *enabler,
		struct lttng_filter_bytecode_node *filter_bytecode)
{
	list_add(&filter_bytecode->node, &enabler->filter_bytecode_head);
	return 0;
}

void lttng_free_enabler_filter_bytecode(struct lttng_enabler *enabler)
{
	struct lttng_filter_bytecode_node *filter_bytecode, *tmp;

	list_for_each_entry_safe(filter_bytecode, tmp,
			&enabler->filter_bytecode_head, node) {
		kfree(filter_bytecode);
	}
}

void lttng_free_event_filter_runtime(struct lttng_event *event)
{
	struct bytecode_runtime *runtime, *tmp;

	list_for_each_entry_safe(runtime, tmp,
			&event->bytecode_runtime_head, p.node) {
		kfree(runtime);
	}
}
Commit	Line	Data
07dfc1d0 MD	1	/*
	2	* lttng-filter.c
	3	*
	4	* LTTng modules filter code.
	5	*
	6	* Copyright (C) 2010-2014 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	7	*
	8	* This library is free software; you can redistribute it and/or
	9	* modify it under the terms of the GNU Lesser General Public
	10	* License as published by the Free Software Foundation; only
	11	* version 2.1 of the License.
	12	*
	13	* This library is distributed in the hope that it will be useful,
	14	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	16	* Lesser General Public License for more details.
	17	*
	18	* You should have received a copy of the GNU Lesser General Public
	19	* License along with this library; if not, write to the Free Software
	20	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
	21	*/
	22
	23	#include <linux/list.h>
	24	#include <linux/slab.h>
	25
	26	#include "lttng-filter.h"
	27
	28	static const char *opnames[] = {
	29	[ FILTER_OP_UNKNOWN ] = "UNKNOWN",
	30
	31	[ FILTER_OP_RETURN ] = "RETURN",
	32
	33	/* binary */
	34	[ FILTER_OP_MUL ] = "MUL",
	35	[ FILTER_OP_DIV ] = "DIV",
	36	[ FILTER_OP_MOD ] = "MOD",
	37	[ FILTER_OP_PLUS ] = "PLUS",
	38	[ FILTER_OP_MINUS ] = "MINUS",
	39	[ FILTER_OP_RSHIFT ] = "RSHIFT",
	40	[ FILTER_OP_LSHIFT ] = "LSHIFT",
	41	[ FILTER_OP_BIN_AND ] = "BIN_AND",
	42	[ FILTER_OP_BIN_OR ] = "BIN_OR",
	43	[ FILTER_OP_BIN_XOR ] = "BIN_XOR",
	44
	45	/* binary comparators */
	46	[ FILTER_OP_EQ ] = "EQ",
	47	[ FILTER_OP_NE ] = "NE",
	48	[ FILTER_OP_GT ] = "GT",
	49	[ FILTER_OP_LT ] = "LT",
	50	[ FILTER_OP_GE ] = "GE",
	51	[ FILTER_OP_LE ] = "LE",
	52
	53	/* string binary comparators */
	54	[ FILTER_OP_EQ_STRING ] = "EQ_STRING",
	55	[ FILTER_OP_NE_STRING ] = "NE_STRING",
	56	[ FILTER_OP_GT_STRING ] = "GT_STRING",
	57	[ FILTER_OP_LT_STRING ] = "LT_STRING",
	58	[ FILTER_OP_GE_STRING ] = "GE_STRING",
	59	[ FILTER_OP_LE_STRING ] = "LE_STRING",
	60
	61	/* s64 binary comparators */
	62	[ FILTER_OP_EQ_S64 ] = "EQ_S64",
	63	[ FILTER_OP_NE_S64 ] = "NE_S64",
	64	[ FILTER_OP_GT_S64 ] = "GT_S64",
65	[ FILTER_OP_LT_S64 ] = "LT_S64",
66	[ FILTER_OP_GE_S64 ] = "GE_S64",
67	[ FILTER_OP_LE_S64 ] = "LE_S64",
68
69	/* double binary comparators */
70	[ FILTER_OP_EQ_DOUBLE ] = "EQ_DOUBLE",
71	[ FILTER_OP_NE_DOUBLE ] = "NE_DOUBLE",
72	[ FILTER_OP_GT_DOUBLE ] = "GT_DOUBLE",
73	[ FILTER_OP_LT_DOUBLE ] = "LT_DOUBLE",
74	[ FILTER_OP_GE_DOUBLE ] = "GE_DOUBLE",
75	[ FILTER_OP_LE_DOUBLE ] = "LE_DOUBLE",
76
77	/* Mixed S64-double binary comparators */
78	[ FILTER_OP_EQ_DOUBLE_S64 ] = "EQ_DOUBLE_S64",
79	[ FILTER_OP_NE_DOUBLE_S64 ] = "NE_DOUBLE_S64",
80	[ FILTER_OP_GT_DOUBLE_S64 ] = "GT_DOUBLE_S64",
81	[ FILTER_OP_LT_DOUBLE_S64 ] = "LT_DOUBLE_S64",
82	[ FILTER_OP_GE_DOUBLE_S64 ] = "GE_DOUBLE_S64",
83	[ FILTER_OP_LE_DOUBLE_S64 ] = "LE_DOUBLE_S64",
84
85	[ FILTER_OP_EQ_S64_DOUBLE ] = "EQ_S64_DOUBLE",
86	[ FILTER_OP_NE_S64_DOUBLE ] = "NE_S64_DOUBLE",
87	[ FILTER_OP_GT_S64_DOUBLE ] = "GT_S64_DOUBLE",
88	[ FILTER_OP_LT_S64_DOUBLE ] = "LT_S64_DOUBLE",
89	[ FILTER_OP_GE_S64_DOUBLE ] = "GE_S64_DOUBLE",
90	[ FILTER_OP_LE_S64_DOUBLE ] = "LE_S64_DOUBLE",
91
92	/* unary */
93	[ FILTER_OP_UNARY_PLUS ] = "UNARY_PLUS",
94	[ FILTER_OP_UNARY_MINUS ] = "UNARY_MINUS",
95	[ FILTER_OP_UNARY_NOT ] = "UNARY_NOT",
96	[ FILTER_OP_UNARY_PLUS_S64 ] = "UNARY_PLUS_S64",
97	[ FILTER_OP_UNARY_MINUS_S64 ] = "UNARY_MINUS_S64",
98	[ FILTER_OP_UNARY_NOT_S64 ] = "UNARY_NOT_S64",
99	[ FILTER_OP_UNARY_PLUS_DOUBLE ] = "UNARY_PLUS_DOUBLE",
100	[ FILTER_OP_UNARY_MINUS_DOUBLE ] = "UNARY_MINUS_DOUBLE",
101	[ FILTER_OP_UNARY_NOT_DOUBLE ] = "UNARY_NOT_DOUBLE",
102
103	/* logical */
104	[ FILTER_OP_AND ] = "AND",
105	[ FILTER_OP_OR ] = "OR",
106
107	/* load field ref */
108	[ FILTER_OP_LOAD_FIELD_REF ] = "LOAD_FIELD_REF",
109	[ FILTER_OP_LOAD_FIELD_REF_STRING ] = "LOAD_FIELD_REF_STRING",
110	[ FILTER_OP_LOAD_FIELD_REF_SEQUENCE ] = "LOAD_FIELD_REF_SEQUENCE",
111	[ FILTER_OP_LOAD_FIELD_REF_S64 ] = "LOAD_FIELD_REF_S64",
112	[ FILTER_OP_LOAD_FIELD_REF_DOUBLE ] = "LOAD_FIELD_REF_DOUBLE",
113
114	/* load from immediate operand */
115	[ FILTER_OP_LOAD_STRING ] = "LOAD_STRING",
116	[ FILTER_OP_LOAD_S64 ] = "LOAD_S64",
117	[ FILTER_OP_LOAD_DOUBLE ] = "LOAD_DOUBLE",
118
119	/* cast */
120	[ FILTER_OP_CAST_TO_S64 ] = "CAST_TO_S64",
121	[ FILTER_OP_CAST_DOUBLE_TO_S64 ] = "CAST_DOUBLE_TO_S64",
122	[ FILTER_OP_CAST_NOP ] = "CAST_NOP",
123
124	/* get context ref */
125	[ FILTER_OP_GET_CONTEXT_REF ] = "GET_CONTEXT_REF",
126	[ FILTER_OP_GET_CONTEXT_REF_STRING ] = "GET_CONTEXT_REF_STRING",
127	[ FILTER_OP_GET_CONTEXT_REF_S64 ] = "GET_CONTEXT_REF_S64",
128	[ FILTER_OP_GET_CONTEXT_REF_DOUBLE ] = "GET_CONTEXT_REF_DOUBLE",
f127e61e MD	129
	130	/* load userspace field ref */
	131	[ FILTER_OP_LOAD_FIELD_REF_USER_STRING ] = "LOAD_FIELD_REF_USER_STRING",
	132	[ FILTER_OP_LOAD_FIELD_REF_USER_SEQUENCE ] = "LOAD_FIELD_REF_USER_SEQUENCE",
07dfc1d0 MD	133	};
	134
	135	const char *lttng_filter_print_op(enum filter_op op)
	136	{
	137	if (op >= NR_FILTER_OPS)
	138	return "UNKNOWN";
	139	else
	140	return opnames[op];
	141	}
	142
	143	static
	144	int apply_field_reloc(struct lttng_event *event,
	145	struct bytecode_runtime *runtime,
	146	uint32_t runtime_len,
	147	uint32_t reloc_offset,
	148	const char *field_name)
	149	{
	150	const struct lttng_event_desc *desc;
	151	const struct lttng_event_field fields, field = NULL;
	152	unsigned int nr_fields, i;
	153	struct field_ref *field_ref;
	154	struct load_op *op;
	155	uint32_t field_offset = 0;
	156
	157	dbg_printk("Apply field reloc: %u %s\n", reloc_offset, field_name);
	158
	159	/* Lookup event by name */
	160	desc = event->desc;
	161	if (!desc)
	162	return -EINVAL;
	163	fields = desc->fields;
	164	if (!fields)
	165	return -EINVAL;
	166	nr_fields = desc->nr_fields;
	167	for (i = 0; i < nr_fields; i++) {
	168	if (!strcmp(fields[i].name, field_name)) {
	169	field = &fields[i];
	170	break;
	171	}
	172	/* compute field offset */
	173	switch (fields[i].type.atype) {
	174	case atype_integer:
	175	case atype_enum:
	176	field_offset += sizeof(int64_t);
	177	break;
	178	case atype_array:
	179	case atype_sequence:
	180	field_offset += sizeof(unsigned long);
	181	field_offset += sizeof(void *);
	182	break;
	183	case atype_string:
	184	field_offset += sizeof(void *);
	185	break;
	186	default:
	187	return -EINVAL;
	188	}
	189	}
	190	if (!field)
	191	return -EINVAL;
	192
	193	/* Check if field offset is too large for 16-bit offset */
f127e61e	194	if (field_offset > LTTNG_KERNEL_FILTER_BYTECODE_MAX_LEN - 1)
07dfc1d0 MD	195	return -EINVAL;
	196
	197	/* set type */
	198	op = (struct load_op *) &runtime->data[reloc_offset];
	199	field_ref = (struct field_ref *) op->data;
	200	switch (field->type.atype) {
	201	case atype_integer:
	202	case atype_enum:
	203	op->op = FILTER_OP_LOAD_FIELD_REF_S64;
	204	break;
	205	case atype_array:
	206	case atype_sequence:
f127e61e MD	207	if (field->user)
	208	op->op = FILTER_OP_LOAD_FIELD_REF_USER_SEQUENCE;
	209	else
	210	op->op = FILTER_OP_LOAD_FIELD_REF_SEQUENCE;
07dfc1d0 MD	211	break;
07dfc1d0 MD	212	case atype_string:
f127e61e MD	213	if (field->user)
	214	op->op = FILTER_OP_LOAD_FIELD_REF_USER_STRING;
	215	else
	216	op->op = FILTER_OP_LOAD_FIELD_REF_STRING;
07dfc1d0 MD	217	break;
	218	default:
	219	return -EINVAL;
	220	}
	221	/* set offset */
	222	field_ref->offset = (uint16_t) field_offset;
	223	return 0;
	224	}
	225
	226	static
	227	int apply_context_reloc(struct lttng_event *event,
	228	struct bytecode_runtime *runtime,
	229	uint32_t runtime_len,
	230	uint32_t reloc_offset,
	231	const char *context_name)
	232	{
	233	struct field_ref *field_ref;
	234	struct load_op *op;
	235	struct lttng_ctx_field *ctx_field;
	236	int idx;
	237
	238	dbg_printk("Apply context reloc: %u %s\n", reloc_offset, context_name);
	239
	240	/* Get context index */
	241	idx = lttng_get_context_index(lttng_static_ctx, context_name);
	242	if (idx < 0)
	243	return -ENOENT;
	244
	245	/* Check if idx is too large for 16-bit offset */
f127e61e	246	if (idx > LTTNG_KERNEL_FILTER_BYTECODE_MAX_LEN - 1)
07dfc1d0 MD	247	return -EINVAL;
	248
	249	/* Get context return type */
	250	ctx_field = &lttng_static_ctx->fields[idx];
	251	op = (struct load_op *) &runtime->data[reloc_offset];
	252	field_ref = (struct field_ref *) op->data;
	253	switch (ctx_field->event_field.type.atype) {
	254	case atype_integer:
	255	case atype_enum:
	256	op->op = FILTER_OP_GET_CONTEXT_REF_S64;
	257	break;
	258	/* Sequence and array supported as string */
	259	case atype_string:
	260	case atype_array:
	261	case atype_sequence:
f127e61e	262	BUG_ON(ctx_field->event_field.user);
07dfc1d0 MD	263	op->op = FILTER_OP_GET_CONTEXT_REF_STRING;
	264	break;
	265	default:
	266	return -EINVAL;
	267	}
	268	/* set offset to context index within channel contexts */
	269	field_ref->offset = (uint16_t) idx;
	270	return 0;
	271	}
	272
	273	static
	274	int apply_reloc(struct lttng_event *event,
	275	struct bytecode_runtime *runtime,
	276	uint32_t runtime_len,
	277	uint32_t reloc_offset,
	278	const char *name)
	279	{
	280	struct load_op *op;
	281
	282	dbg_printk("Apply reloc: %u %s\n", reloc_offset, name);
	283
	284	/* Ensure that the reloc is within the code */
	285	if (runtime_len - reloc_offset < sizeof(uint16_t))
	286	return -EINVAL;
	287
	288	op = (struct load_op *) &runtime->data[reloc_offset];
	289	switch (op->op) {
	290	case FILTER_OP_LOAD_FIELD_REF:
	291	return apply_field_reloc(event, runtime, runtime_len,
	292	reloc_offset, name);
	293	case FILTER_OP_GET_CONTEXT_REF:
	294	return apply_context_reloc(event, runtime, runtime_len,
	295	reloc_offset, name);
	296	default:
	297	printk(KERN_WARNING "Unknown reloc op type %u\n", op->op);
	298	return -EINVAL;
	299	}
	300	return 0;
	301	}
	302
	303	static
	304	int bytecode_is_linked(struct lttng_filter_bytecode_node *filter_bytecode,
	305	struct lttng_event *event)
	306	{
	307	struct lttng_bytecode_runtime *bc_runtime;
	308
	309	list_for_each_entry(bc_runtime,
	310	&event->bytecode_runtime_head, node) {
	311	if (bc_runtime->bc == filter_bytecode)
	312	return 1;
	313	}
	314	return 0;
	315	}
	316
	317	/*
	318	* Take a bytecode with reloc table and link it to an event to create a
	319	* bytecode runtime.
	320	*/
	321	static
	322	int _lttng_filter_event_link_bytecode(struct lttng_event *event,
	323	struct lttng_filter_bytecode_node *filter_bytecode,
	324	struct list_head *insert_loc)
	325	{
	326	int ret, offset, next_offset;
327	struct bytecode_runtime *runtime = NULL;
328	size_t runtime_alloc_len;
329
330	if (!filter_bytecode)
331	return 0;
332	/* Bytecode already linked */
333	if (bytecode_is_linked(filter_bytecode, event))
334	return 0;
335
336	dbg_printk("Linking...\n");
337
338	/* We don't need the reloc table in the runtime */
339	runtime_alloc_len = sizeof(*runtime) + filter_bytecode->bc.reloc_offset;
340	runtime = kzalloc(runtime_alloc_len, GFP_KERNEL);
341	if (!runtime) {
342	ret = -ENOMEM;
343	goto alloc_error;
344	}
345	runtime->p.bc = filter_bytecode;
346	runtime->len = filter_bytecode->bc.reloc_offset;
347	/* copy original bytecode */
348	memcpy(runtime->data, filter_bytecode->bc.data, runtime->len);
349	/*
350	* apply relocs. Those are a uint16_t (offset in bytecode)
351	* followed by a string (field name).
352	*/
353	for (offset = filter_bytecode->bc.reloc_offset;
354	offset < filter_bytecode->bc.len;
355	offset = next_offset) {
356	uint16_t reloc_offset =
357	(uint16_t ) &filter_bytecode->bc.data[offset];
358	const char *name =
359	(const char *) &filter_bytecode->bc.data[offset + sizeof(uint16_t)];
360
361	ret = apply_reloc(event, runtime, runtime->len, reloc_offset, name);
362	if (ret) {
363	goto link_error;
364	}
365	next_offset = offset + sizeof(uint16_t) + strlen(name) + 1;
366	}
367	/* Validate bytecode */
368	ret = lttng_filter_validate_bytecode(runtime);
369	if (ret) {
370	goto link_error;
371	}
372	/* Specialize bytecode */
373	ret = lttng_filter_specialize_bytecode(runtime);
374	if (ret) {
375	goto link_error;
376	}
377	runtime->p.filter = lttng_filter_interpret_bytecode;
378	runtime->p.link_failed = 0;
379	list_add_rcu(&runtime->p.node, insert_loc);
380	dbg_printk("Linking successful.\n");
381	return 0;
382
383	link_error:
384	runtime->p.filter = lttng_filter_false;
385	runtime->p.link_failed = 1;
386	list_add_rcu(&runtime->p.node, insert_loc);
387	alloc_error:
388	dbg_printk("Linking failed.\n");
389	return ret;
390	}
391
392	void lttng_filter_sync_state(struct lttng_bytecode_runtime *runtime)
393	{
394	struct lttng_filter_bytecode_node *bc = runtime->bc;
395
396	if (!bc->enabler->enabled \|\| runtime->link_failed)
397	runtime->filter = lttng_filter_false;
398	else
399	runtime->filter = lttng_filter_interpret_bytecode;
400	}
401
402	/*
403	* Link bytecode for all enablers referenced by an event.
404	*/
405	void lttng_enabler_event_link_bytecode(struct lttng_event *event,
406	struct lttng_enabler *enabler)
407	{
408	struct lttng_filter_bytecode_node *bc;
409	struct lttng_bytecode_runtime *runtime;
410
411	/* Can only be called for events with desc attached */
412	WARN_ON_ONCE(!event->desc);
413
414	/* Link each bytecode. */
415	list_for_each_entry(bc, &enabler->filter_bytecode_head, node) {
416	int found = 0, ret;
417	struct list_head *insert_loc;
418
419	list_for_each_entry(runtime,
420	&event->bytecode_runtime_head, node) {
421	if (runtime->bc == bc) {
422	found = 1;
423	break;
424	}
425	}
426	/* Skip bytecode already linked */
427	if (found)
428	continue;
429
430	/*
431	* Insert at specified priority (seqnum) in increasing
432	* order.
433	*/
434	list_for_each_entry_reverse(runtime,
435	&event->bytecode_runtime_head, node) {
436	if (runtime->bc->bc.seqnum < bc->bc.seqnum) {
437	/* insert here */
438	insert_loc = &runtime->node;
439	goto add_within;
440	}
441	}
442	/* Add to head to list */
443	insert_loc = &event->bytecode_runtime_head;
444	add_within:
445	dbg_printk("linking bytecode\n");
446	ret = _lttng_filter_event_link_bytecode(event, bc,
447	insert_loc);
448	if (ret) {
449	dbg_printk("[lttng filter] warning: cannot link event bytecode\n");
450	}
451	}
452	}
453
454	/*
455	* We own the filter_bytecode if we return success.
456	*/
457	int lttng_filter_enabler_attach_bytecode(struct lttng_enabler *enabler,
458	struct lttng_filter_bytecode_node *filter_bytecode)
459	{
460	list_add(&filter_bytecode->node, &enabler->filter_bytecode_head);
461	return 0;
462	}
463
464	void lttng_free_enabler_filter_bytecode(struct lttng_enabler *enabler)
465	{
466	struct lttng_filter_bytecode_node filter_bytecode, tmp;
467
468	list_for_each_entry_safe(filter_bytecode, tmp,
469	&enabler->filter_bytecode_head, node) {
470	kfree(filter_bytecode);
471	}
472	}
473
474	void lttng_free_event_filter_runtime(struct lttng_event *event)
475	{
476	struct bytecode_runtime runtime, tmp;
477
478	list_for_each_entry_safe(runtime, tmp,
479	&event->bytecode_runtime_head, p.node) {
480	kfree(runtime);
481	}
482	}