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 <stdbool.h>
  33 #include <helper.h>
  34 #include <lttng/ust-events.h>
  35 #include <lttng/ust-context-provider.h>
  36 #include <stdint.h>
  37 #include <assert.h>
  38 #include <errno.h>
  39 #include <string.h>
  40 #include <inttypes.h>
  41 #include <limits.h>
  42 #include <usterr-signal-safe.h>
  43 #include "filter-bytecode.h"
  44
  45 /* Filter stack length, in number of entries */
  46 #define FILTER_STACK_LEN        10      /* includes 2 dummy */
  47 #define FILTER_STACK_EMPTY      1
  48
  49 #define FILTER_MAX_DATA_LEN     65536
  50
  51 #ifndef min_t
  52 #define min_t(type, a, b)       \
  53                 ((type) (a) < (type) (b) ? (type) (a) : (type) (b))
  54 #endif
  55
  56 #ifndef likely
  57 #define likely(x)       __builtin_expect(!!(x), 1)
  58 #endif
  59
  60 #ifndef unlikely
  61 #define unlikely(x)     __builtin_expect(!!(x), 0)
  62 #endif
  63
  64 #ifdef DEBUG
  65 #define dbg_printf(fmt, args...)                                \
  66         printf("[debug bytecode in %s:%s@%u] " fmt,             \
  67                 __FILE__, __func__, __LINE__, ## args)
  68 #else
  69 #define dbg_printf(fmt, args...)                                \
  70 do {                                                            \
  71         /* do nothing but check printf format */                \
  72         if (0)                                                  \
  73                 printf("[debug bytecode in %s:%s@%u] " fmt,     \
  74                         __FILE__, __func__, __LINE__, ## args); \
  75 } while (0)
  76 #endif
  77
  78 /* Linked bytecode. Child of struct lttng_bytecode_runtime. */
  79 struct bytecode_runtime {
  80         struct lttng_bytecode_runtime p;
  81         size_t data_len;
  82         size_t data_alloc_len;
  83         char *data;
  84         uint16_t len;
  85         char code[0];
  86 };
  87
  88 enum entry_type {
  89         REG_S64,
  90         REG_DOUBLE,
  91         REG_STRING,
  92         REG_STAR_GLOB_STRING,
  93         REG_UNKNOWN,
  94         REG_PTR,
  95 };
  96
  97 enum load_type {
  98         LOAD_ROOT_CONTEXT,
  99         LOAD_ROOT_APP_CONTEXT,
 100         LOAD_ROOT_PAYLOAD,
 101         LOAD_OBJECT,
 102 };
 103
 104 enum object_type {
 105         OBJECT_TYPE_S8,
 106         OBJECT_TYPE_S16,
 107         OBJECT_TYPE_S32,
 108         OBJECT_TYPE_S64,
 109         OBJECT_TYPE_U8,
 110         OBJECT_TYPE_U16,
 111         OBJECT_TYPE_U32,
 112         OBJECT_TYPE_U64,
 113
 114         OBJECT_TYPE_DOUBLE,
 115         OBJECT_TYPE_STRING,
 116         OBJECT_TYPE_STRING_SEQUENCE,
 117
 118         OBJECT_TYPE_SEQUENCE,
 119         OBJECT_TYPE_ARRAY,
 120         OBJECT_TYPE_STRUCT,
 121         OBJECT_TYPE_VARIANT,
 122
 123         OBJECT_TYPE_DYNAMIC,
 124 };
 125
 126 struct filter_get_index_data {
 127         uint64_t offset;        /* in bytes */
 128         size_t ctx_index;
 129         size_t array_len;
 130         struct {
 131                 size_t len;
 132                 enum object_type type;
 133                 bool rev_bo;    /* reverse byte order */
 134         } elem;
 135 };
 136
 137 /* Validation stack */
 138 struct vstack_load {
 139         enum load_type type;
 140         enum object_type object_type;
 141         const struct lttng_event_field *field;
 142         bool rev_bo;    /* reverse byte order */
 143 };
 144
 145 struct vstack_entry {
 146         enum entry_type type;
 147         struct vstack_load load;
 148 };
 149
 150 struct vstack {
 151         int top;        /* top of stack */
 152         struct vstack_entry e[FILTER_STACK_LEN];
 153 };
 154
 155 static inline
 156 void vstack_init(struct vstack *stack)
 157 {
 158         stack->top = -1;
 159 }
 160
 161 static inline
 162 struct vstack_entry *vstack_ax(struct vstack *stack)
 163 {
 164         if (unlikely(stack->top < 0))
 165                 return NULL;
 166         return &stack->e[stack->top];
 167 }
 168
 169 static inline
 170 struct vstack_entry *vstack_bx(struct vstack *stack)
 171 {
 172         if (unlikely(stack->top < 1))
 173                 return NULL;
 174         return &stack->e[stack->top - 1];
 175 }
 176
 177 static inline
 178 int vstack_push(struct vstack *stack)
 179 {
 180         if (stack->top >= FILTER_STACK_LEN - 1) {
 181                 ERR("Stack full\n");
 182                 return -EINVAL;
 183         }
 184         ++stack->top;
 185         return 0;
 186 }
 187
 188 static inline
 189 int vstack_pop(struct vstack *stack)
 190 {
 191         if (unlikely(stack->top < 0)) {
 192                 ERR("Stack empty\n");
 193                 return -EINVAL;
 194         }
 195         stack->top--;
 196         return 0;
 197 }
 198
 199 /* Execution stack */
 200 enum estack_string_literal_type {
 201         ESTACK_STRING_LITERAL_TYPE_NONE,
 202         ESTACK_STRING_LITERAL_TYPE_PLAIN,
 203         ESTACK_STRING_LITERAL_TYPE_STAR_GLOB,
 204 };
 205
 206 struct load_ptr {
 207         enum load_type type;
 208         enum object_type object_type;
 209         const void *ptr;
 210         bool rev_bo;
 211         /* Temporary place-holders for contexts. */
 212         union {
 213                 int64_t s64;
 214                 uint64_t u64;
 215                 double d;
 216         } u;
 217         /*
 218          * "field" is only needed when nested under a variant, in which
 219          * case we cannot specialize the nested operations.
 220          */
 221         const struct lttng_event_field *field;
 222 };
 223
 224 struct estack_entry {
 225         enum entry_type type;   /* For dynamic typing. */
 226         union {
 227                 int64_t v;
 228                 double d;
 229
 230                 struct {
 231                         const char *str;
 232                         size_t seq_len;
 233                         enum estack_string_literal_type literal_type;
 234                 } s;
 235                 struct load_ptr ptr;
 236         } u;
 237 };
 238
 239 struct estack {
 240         int top;        /* top of stack */
 241         struct estack_entry e[FILTER_STACK_LEN];
 242 };
 243
 244 /*
 245  * Always use aliased type for ax/bx (top of stack).
 246  * When ax/bx are S64, use aliased value.
 247  */
 248 #define estack_ax_v     ax
 249 #define estack_bx_v     bx
 250 #define estack_ax_t     ax_t
 251 #define estack_bx_t     bx_t
 252
 253 /*
 254  * ax and bx registers can hold either integer, double or string.
 255  */
 256 #define estack_ax(stack, top)                                   \
 257         ({                                                      \
 258                 assert((top) > FILTER_STACK_EMPTY);             \
 259                 &(stack)->e[top];                               \
 260         })
 261
 262 #define estack_bx(stack, top)                                   \
 263         ({                                                      \
 264                 assert((top) > FILTER_STACK_EMPTY + 1);         \
 265                 &(stack)->e[(top) - 1];                         \
 266         })
 267
 268 /*
 269  * Currently, only integers (REG_S64) can be pushed into the stack.
 270  */
 271 #define estack_push(stack, top, ax, bx, ax_t, bx_t)             \
 272         do {                                                    \
 273                 assert((top) < FILTER_STACK_LEN - 1);           \
 274                 (stack)->e[(top) - 1].u.v = (bx);               \
 275                 (stack)->e[(top) - 1].type = (bx_t);            \
 276                 (bx) = (ax);                                    \
 277                 (bx_t) = (ax_t);                                \
 278                 ++(top);                                        \
 279         } while (0)
 280
 281 #define estack_pop(stack, top, ax, bx, ax_t, bx_t)              \
 282         do {                                                    \
 283                 assert((top) > FILTER_STACK_EMPTY);             \
 284                 (ax) = (bx);                                    \
 285                 (ax_t) = (bx_t);                                \
 286                 (bx) = (stack)->e[(top) - 2].u.v;               \
 287                 (bx_t) = (stack)->e[(top) - 2].type;            \
 288                 (top)--;                                        \
 289         } while (0)
 290
 291 const char *print_op(enum filter_op op);
 292
 293 int lttng_filter_validate_bytecode(struct bytecode_runtime *bytecode);
 294 int lttng_filter_specialize_bytecode(struct lttng_event *event,
 295                 struct bytecode_runtime *bytecode);
 296
 297 uint64_t lttng_filter_false(void *filter_data,
 298                 const char *filter_stack_data);
 299 uint64_t lttng_filter_interpret_bytecode(void *filter_data,
 300                 const char *filter_stack_data);
 301
 302 #endif /* _LTTNG_FILTER_H */