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) 2010-2016 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  10  *
  11  * Permission is hereby granted, free of charge, to any person obtaining a copy
  12  * of this software and associated documentation files (the "Software"), to deal
  13  * in the Software without restriction, including without limitation the rights
  14  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  15  * copies of the Software, and to permit persons to whom the Software is
  16  * furnished to do so, subject to the following conditions:
  17  *
  18  * The above copyright notice and this permission notice shall be included in
  19  * all copies or substantial portions of the Software.
  20  *
  21  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  22  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  23  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  24  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  25  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  26  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  27  * SOFTWARE.
  28  */
  29
  30 #include <errno.h>
  31 #include <stdio.h>
  32 #include <helper.h>
  33 #include <lttng/ust-events.h>
  34 #include <lttng/ust-context-provider.h>
  35 #include <stdint.h>
  36 #include <assert.h>
  37 #include <errno.h>
  38 #include <string.h>
  39 #include <inttypes.h>
  40 #include <limits.h>
  41 #include <usterr-signal-safe.h>
  42 #include "filter-bytecode.h"
  43
  44 /* Filter stack length, in number of entries */
  45 #define FILTER_STACK_LEN        10      /* includes 2 dummy */
  46 #define FILTER_STACK_EMPTY      1
  47
  48 #ifndef min_t
  49 #define min_t(type, a, b)       \
  50                 ((type) (a) < (type) (b) ? (type) (a) : (type) (b))
  51 #endif
  52
  53 #ifndef likely
  54 #define likely(x)       __builtin_expect(!!(x), 1)
  55 #endif
  56
  57 #ifndef unlikely
  58 #define unlikely(x)     __builtin_expect(!!(x), 0)
  59 #endif
  60
  61 #ifdef DEBUG
  62 #define dbg_printf(fmt, args...)                                \
  63         printf("[debug bytecode in %s:%s@%u] " fmt,             \
  64                 __FILE__, __func__, __LINE__, ## args)
  65 #else
  66 #define dbg_printf(fmt, args...)                                \
  67 do {                                                            \
  68         /* do nothing but check printf format */                \
  69         if (0)                                                  \
  70                 printf("[debug bytecode in %s:%s@%u] " fmt,     \
  71                         __FILE__, __func__, __LINE__, ## args); \
  72 } while (0)
  73 #endif
  74
  75 /* Linked bytecode. Child of struct lttng_bytecode_runtime. */
  76 struct bytecode_runtime {
  77         struct lttng_bytecode_runtime p;
  78         uint16_t len;
  79         char data[0];
  80 };
  81
  82 enum entry_type {
  83         REG_S64,
  84         REG_DOUBLE,
  85         REG_STRING,
  86         REG_UNKNOWN,
  87 };
  88
  89 /* Validation stack */
  90 struct vstack_entry {
  91         enum entry_type type;
  92 };
  93
  94 struct vstack {
  95         int top;        /* top of stack */
  96         struct vstack_entry e[FILTER_STACK_LEN];
  97 };
  98
  99 static inline
 100 void vstack_init(struct vstack *stack)
 101 {
 102         stack->top = -1;
 103 }
 104
 105 static inline
 106 struct vstack_entry *vstack_ax(struct vstack *stack)
 107 {
 108         if (unlikely(stack->top < 0))
 109                 return NULL;
 110         return &stack->e[stack->top];
 111 }
 112
 113 static inline
 114 struct vstack_entry *vstack_bx(struct vstack *stack)
 115 {
 116         if (unlikely(stack->top < 1))
 117                 return NULL;
 118         return &stack->e[stack->top - 1];
 119 }
 120
 121 static inline
 122 int vstack_push(struct vstack *stack)
 123 {
 124         if (stack->top >= FILTER_STACK_LEN - 1) {
 125                 ERR("Stack full\n");
 126                 return -EINVAL;
 127         }
 128         ++stack->top;
 129         return 0;
 130 }
 131
 132 static inline
 133 int vstack_pop(struct vstack *stack)
 134 {
 135         if (unlikely(stack->top < 0)) {
 136                 ERR("Stack empty\n");
 137                 return -EINVAL;
 138         }
 139         stack->top--;
 140         return 0;
 141 }
 142
 143 /* Execution stack */
 144 struct estack_entry {
 145         enum entry_type type;   /* For dynamic typing. */
 146         union {
 147                 int64_t v;
 148                 double d;
 149
 150                 struct {
 151                         const char *str;
 152                         size_t seq_len;
 153                         int literal;            /* is string literal ? */
 154                 } s;
 155         } u;
 156 };
 157
 158 struct estack {
 159         int top;        /* top of stack */
 160         struct estack_entry e[FILTER_STACK_LEN];
 161 };
 162
 163 /*
 164  * Always use aliased type for ax/bx (top of stack).
 165  * When ax/bx are S64, use aliased value.
 166  */
 167 #define estack_ax_v     ax
 168 #define estack_bx_v     bx
 169 #define estack_ax_t     ax_t
 170 #define estack_bx_t     bx_t
 171
 172 /*
 173  * ax and bx registers can hold either integer, double or string.
 174  */
 175 #define estack_ax(stack, top)                                   \
 176         ({                                                      \
 177                 assert((top) > FILTER_STACK_EMPTY);             \
 178                 &(stack)->e[top];                               \
 179         })
 180
 181 #define estack_bx(stack, top)                                   \
 182         ({                                                      \
 183                 assert((top) > FILTER_STACK_EMPTY + 1);         \
 184                 &(stack)->e[(top) - 1];                         \
 185         })
 186
 187 /*
 188  * Currently, only integers (REG_S64) can be pushed into the stack.
 189  */
 190 #define estack_push(stack, top, ax, bx, ax_t, bx_t)             \
 191         do {                                                    \
 192                 assert((top) < FILTER_STACK_LEN - 1);           \
 193                 (stack)->e[(top) - 1].u.v = (bx);               \
 194                 (stack)->e[(top) - 1].type = (bx_t);            \
 195                 (bx) = (ax);                                    \
 196                 (bx_t) = (ax_t);                                \
 197                 ++(top);                                        \
 198         } while (0)
 199
 200 #define estack_pop(stack, top, ax, bx, ax_t, bx_t)              \
 201         do {                                                    \
 202                 assert((top) > FILTER_STACK_EMPTY);             \
 203                 (ax) = (bx);                                    \
 204                 (ax_t) = (bx_t);                                \
 205                 (bx) = (stack)->e[(top) - 2].u.v;               \
 206                 (bx_t) = (stack)->e[(top) - 2].type;            \
 207                 (top)--;                                        \
 208         } while (0)
 209
 210 const char *print_op(enum filter_op op);
 211
 212 int lttng_filter_validate_bytecode(struct bytecode_runtime *bytecode);
 213 int lttng_filter_specialize_bytecode(struct bytecode_runtime *bytecode);
 214
 215 uint64_t lttng_filter_false(void *filter_data,
 216                 const char *filter_stack_data);
 217 uint64_t lttng_filter_interpret_bytecode(void *filter_data,
 218                 const char *filter_stack_data);
 219
 220 #endif /* _LTTNG_FILTER_H */