liblttng-ust/lttng-filter.h

   1 #ifndef _LTTNG_FILTER_H
   2 #define _LTTNG_FILTER_H
   3
   4 /*
   5  * lttng-filter.h
   6  *
   7  * LTTng UST filter header.
   8  *
   9  * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  10  *
  11  * This library is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU Lesser General Public
  13  * License as published by the Free Software Foundation; only
  14  * version 2.1 of the License.
  15  *
  16  * This library is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  19  * Lesser General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU Lesser General Public
  22  * License along with this library; if not, write to the Free Software
  23  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  24  */
  25
  26 #include <errno.h>
  27 #include <stdio.h>
  28 #include <helper.h>
  29 #include <lttng/ust-events.h>
  30 #include <stdint.h>
  31 #include <assert.h>
  32 #include <errno.h>
  33 #include <string.h>
  34 #include <inttypes.h>
  35 #include <limits.h>
  36 #include <usterr-signal-safe.h>
  37 #include "filter-bytecode.h"
  38
  39 /* Filter stack length, in number of entries */
  40 #define FILTER_STACK_LEN        8
  41
  42 #ifndef min_t
  43 #define min_t(type, a, b)       \
  44                 ((type) (a) < (type) (b) ? (type) (a) : (type) (b))
  45 #endif
  46
  47 #ifndef likely
  48 #define likely(x)       __builtin_expect(!!(x), 1)
  49 #endif
  50
  51 #ifndef unlikely
  52 #define unlikely(x)     __builtin_expect(!!(x), 0)
  53 #endif
  54
  55 #ifdef DEBUG
  56 #define dbg_printf(fmt, args...)     printf("[debug bytecode] " fmt, ## args)
  57 #else
  58 #define dbg_printf(fmt, args...)                                \
  59 do {                                                            \
  60         /* do nothing but check printf format */                \
  61         if (0)                                                  \
  62                 printf("[debug bytecode] " fmt, ## args);       \
  63 } while (0)
  64 #endif
  65
  66 /* Linked bytecode */
  67 struct bytecode_runtime {
  68         uint16_t len;
  69         char data[0];
  70 };
  71
  72 enum entry_type {
  73         REG_S64,
  74         REG_DOUBLE,
  75         REG_STRING,
  76         REG_TYPE_UNKNOWN,
  77 };
  78
  79 /* Validation stack */
  80 struct vstack_entry {
  81         enum entry_type type;
  82 };
  83
  84 struct vstack {
  85         int top;        /* top of stack */
  86         struct vstack_entry e[FILTER_STACK_LEN];
  87 };
  88
  89 static inline
  90 void vstack_init(struct vstack *stack)
  91 {
  92         stack->top = -1;
  93 }
  94
  95 static inline
  96 struct vstack_entry *vstack_ax(struct vstack *stack)
  97 {
  98         if (unlikely(stack->top < 0))
  99                 return NULL;
 100         return &stack->e[stack->top];
 101 }
 102
 103 static inline
 104 struct vstack_entry *vstack_bx(struct vstack *stack)
 105 {
 106         if (unlikely(stack->top < 1))
 107                 return NULL;
 108         return &stack->e[stack->top - 1];
 109 }
 110
 111 static inline
 112 int vstack_push(struct vstack *stack)
 113 {
 114         if (stack->top >= FILTER_STACK_LEN - 1) {
 115                 ERR("Stack full\n");
 116                 return -EINVAL;
 117         }
 118         ++stack->top;
 119         return 0;
 120 }
 121
 122 static inline
 123 int vstack_pop(struct vstack *stack)
 124 {
 125         if (unlikely(stack->top < 0)) {
 126                 ERR("Stack empty\n");
 127                 return -EINVAL;
 128         }
 129         stack->top--;
 130         return 0;
 131 }
 132
 133 /* Execution stack */
 134 struct estack_entry {
 135         union {
 136                 int64_t v;
 137                 double d;
 138
 139                 struct {
 140                         const char *str;
 141                 size_t seq_len;
 142                 int literal;            /* is string literal ? */
 143                 } s;
 144         } u;
 145 };
 146
 147 struct estack {
 148         int top;        /* top of stack */
 149         struct estack_entry e[FILTER_STACK_LEN];
 150 };
 151
 152 static inline
 153 void estack_init(struct estack *stack)
 154 {
 155         stack->top = -1;
 156 }
 157
 158 static inline
 159 struct estack_entry *estack_ax(struct estack *stack)
 160 {
 161         assert(stack->top >= 0);
 162         return &stack->e[stack->top];
 163 }
 164
 165 static inline
 166 struct estack_entry *estack_bx(struct estack *stack)
 167 {
 168         assert(stack->top >= 1);
 169         return &stack->e[stack->top - 1];
 170 }
 171
 172 static inline
 173 void estack_push(struct estack *stack)
 174 {
 175         assert(stack->top < FILTER_STACK_LEN - 1);
 176         ++stack->top;
 177 }
 178
 179 static inline
 180 void estack_pop(struct estack *stack)
 181 {
 182         assert(stack->top >= 0);
 183         stack->top--;
 184 }
 185
 186 const char *print_op(enum filter_op op);
 187
 188 int lttng_filter_validate_bytecode(struct bytecode_runtime *bytecode);
 189 int lttng_filter_specialize_bytecode(struct bytecode_runtime *bytecode);
 190
 191 int lttng_filter_false(void *filter_data,
 192                 const char *filter_stack_data);
 193 int lttng_filter_interpret_bytecode(void *filter_data,
 194                 const char *filter_stack_data);
 195
 196 #endif /* _LTTNG_FILTER_H */