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        10      /* includes 2 dummy */
  41 #define FILTER_STACK_EMPTY      1
  42
  43 #ifndef min_t
  44 #define min_t(type, a, b)       \
  45                 ((type) (a) < (type) (b) ? (type) (a) : (type) (b))
  46 #endif
  47
  48 #ifndef likely
  49 #define likely(x)       __builtin_expect(!!(x), 1)
  50 #endif
  51
  52 #ifndef unlikely
  53 #define unlikely(x)     __builtin_expect(!!(x), 0)
  54 #endif
  55
  56 #ifdef DEBUG
  57 #define dbg_printf(fmt, args...)                                \
  58         printf("[debug bytecode in %s:%s@%u] " fmt,             \
  59                 __FILE__, __func__, __LINE__, ## args)
  60 #else
  61 #define dbg_printf(fmt, args...)                                \
  62 do {                                                            \
  63         /* do nothing but check printf format */                \
  64         if (0)                                                  \
  65                 printf("[debug bytecode in %s:%s@%u] " fmt,     \
  66                         __FILE__, __func__, __LINE__, ## args); \
  67 } while (0)
  68 #endif
  69
  70 /* Linked bytecode. Child of struct lttng_bytecode_runtime. */
  71 struct bytecode_runtime {
  72         struct lttng_bytecode_runtime p;
  73         uint16_t len;
  74         char data[0];
  75 };
  76
  77 enum entry_type {
  78         REG_S64,
  79         REG_DOUBLE,
  80         REG_STRING,
  81         REG_TYPE_UNKNOWN,
  82 };
  83
  84 /* Validation stack */
  85 struct vstack_entry {
  86         enum entry_type type;
  87 };
  88
  89 struct vstack {
  90         int top;        /* top of stack */
  91         struct vstack_entry e[FILTER_STACK_LEN];
  92 };
  93
  94 static inline
  95 void vstack_init(struct vstack *stack)
  96 {
  97         stack->top = -1;
  98 }
  99
 100 static inline
 101 struct vstack_entry *vstack_ax(struct vstack *stack)
 102 {
 103         if (unlikely(stack->top < 0))
 104                 return NULL;
 105         return &stack->e[stack->top];
 106 }
 107
 108 static inline
 109 struct vstack_entry *vstack_bx(struct vstack *stack)
 110 {
 111         if (unlikely(stack->top < 1))
 112                 return NULL;
 113         return &stack->e[stack->top - 1];
 114 }
 115
 116 static inline
 117 int vstack_push(struct vstack *stack)
 118 {
 119         if (stack->top >= FILTER_STACK_LEN - 1) {
 120                 ERR("Stack full\n");
 121                 return -EINVAL;
 122         }
 123         ++stack->top;
 124         return 0;
 125 }
 126
 127 static inline
 128 int vstack_pop(struct vstack *stack)
 129 {
 130         if (unlikely(stack->top < 0)) {
 131                 ERR("Stack empty\n");
 132                 return -EINVAL;
 133         }
 134         stack->top--;
 135         return 0;
 136 }
 137
 138 /* Execution stack */
 139 struct estack_entry {
 140         union {
 141                 int64_t v;
 142                 double d;
 143
 144                 struct {
 145                         const char *str;
 146                         size_t seq_len;
 147                         int literal;            /* is string literal ? */
 148                 } s;
 149         } u;
 150 };
 151
 152 struct estack {
 153         int top;        /* top of stack */
 154         struct estack_entry e[FILTER_STACK_LEN];
 155 };
 156
 157 #define estack_ax_v     ax
 158 #define estack_bx_v     bx
 159
 160 #define estack_ax(stack, top)                                   \
 161         ({                                                      \
 162                 assert((top) > FILTER_STACK_EMPTY);             \
 163                 &(stack)->e[top];                               \
 164         })
 165
 166 #define estack_bx(stack, top)                                   \
 167         ({                                                      \
 168                 assert((top) > FILTER_STACK_EMPTY + 1);         \
 169                 &(stack)->e[(top) - 1];                         \
 170         })
 171
 172 #define estack_push(stack, top, ax, bx)                         \
 173         do {                                                    \
 174                 assert((top) < FILTER_STACK_LEN - 1);           \
 175                 (stack)->e[(top) - 1].u.v = (bx);               \
 176                 (bx) = (ax);                                    \
 177                 ++(top);                                        \
 178         } while (0)
 179
 180 #define estack_pop(stack, top, ax, bx)                          \
 181         do {                                                    \
 182                 assert((top) > FILTER_STACK_EMPTY);             \
 183                 (ax) = (bx);                                    \
 184                 (bx) = (stack)->e[(top) - 2].u.v;               \
 185                 (top)--;                                        \
 186         } while (0)
 187
 188 const char *print_op(enum filter_op op);
 189
 190 int lttng_filter_validate_bytecode(struct bytecode_runtime *bytecode);
 191 int lttng_filter_specialize_bytecode(struct bytecode_runtime *bytecode);
 192
 193 uint64_t lttng_filter_false(void *filter_data,
 194                 const char *filter_stack_data);
 195 uint64_t lttng_filter_interpret_bytecode(void *filter_data,
 196                 const char *filter_stack_data);
 197
 198 #endif /* _LTTNG_FILTER_H */