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_U64,
  91         REG_DOUBLE,
  92         REG_STRING,
  93         REG_STAR_GLOB_STRING,
  94         REG_UNKNOWN,
  95         REG_PTR,
  96 };
  97
  98 enum load_type {
  99         LOAD_ROOT_CONTEXT,
 100         LOAD_ROOT_APP_CONTEXT,
 101         LOAD_ROOT_PAYLOAD,
 102         LOAD_OBJECT,
 103 };
 104
 105 enum object_type {
 106         OBJECT_TYPE_S8,
 107         OBJECT_TYPE_S16,
 108         OBJECT_TYPE_S32,
 109         OBJECT_TYPE_S64,
 110         OBJECT_TYPE_U8,
 111         OBJECT_TYPE_U16,
 112         OBJECT_TYPE_U32,
 113         OBJECT_TYPE_U64,
 114
 115         OBJECT_TYPE_DOUBLE,
 116         OBJECT_TYPE_STRING,
 117         OBJECT_TYPE_STRING_SEQUENCE,
 118
 119         OBJECT_TYPE_SEQUENCE,
 120         OBJECT_TYPE_ARRAY,
 121         OBJECT_TYPE_STRUCT,
 122         OBJECT_TYPE_VARIANT,
 123
 124         OBJECT_TYPE_DYNAMIC,
 125 };
 126
 127 struct filter_get_index_data {
 128         uint64_t offset;        /* in bytes */
 129         size_t ctx_index;
 130         size_t array_len;
 131         struct {
 132                 size_t len;
 133                 enum object_type type;
 134                 bool rev_bo;    /* reverse byte order */
 135         } elem;
 136 };
 137
 138 /* Validation stack */
 139 struct vstack_load {
 140         enum load_type type;
 141         enum object_type object_type;
 142         const struct lttng_event_field *field;
 143         bool rev_bo;    /* reverse byte order */
 144 };
 145
 146 struct vstack_entry {
 147         enum entry_type type;
 148         struct vstack_load load;
 149 };
 150
 151 struct vstack {
 152         int top;        /* top of stack */
 153         struct vstack_entry e[FILTER_STACK_LEN];
 154 };
 155
 156 static inline
 157 void vstack_init(struct vstack *stack)
 158 {
 159         stack->top = -1;
 160 }
 161
 162 static inline
 163 struct vstack_entry *vstack_ax(struct vstack *stack)
 164 {
 165         if (unlikely(stack->top < 0))
 166                 return NULL;
 167         return &stack->e[stack->top];
 168 }
 169
 170 static inline
 171 struct vstack_entry *vstack_bx(struct vstack *stack)
 172 {
 173         if (unlikely(stack->top < 1))
 174                 return NULL;
 175         return &stack->e[stack->top - 1];
 176 }
 177
 178 static inline
 179 int vstack_push(struct vstack *stack)
 180 {
 181         if (stack->top >= FILTER_STACK_LEN - 1) {
 182                 ERR("Stack full\n");
 183                 return -EINVAL;
 184         }
 185         ++stack->top;
 186         return 0;
 187 }
 188
 189 static inline
 190 int vstack_pop(struct vstack *stack)
 191 {
 192         if (unlikely(stack->top < 0)) {
 193                 ERR("Stack empty\n");
 194                 return -EINVAL;
 195         }
 196         stack->top--;
 197         return 0;
 198 }
 199
 200 /* Execution stack */
 201 enum estack_string_literal_type {
 202         ESTACK_STRING_LITERAL_TYPE_NONE,
 203         ESTACK_STRING_LITERAL_TYPE_PLAIN,
 204         ESTACK_STRING_LITERAL_TYPE_STAR_GLOB,
 205 };
 206
 207 struct load_ptr {
 208         enum load_type type;
 209         enum object_type object_type;
 210         const void *ptr;
 211         bool rev_bo;
 212         /* Temporary place-holders for contexts. */
 213         union {
 214                 int64_t s64;
 215                 uint64_t u64;
 216                 double d;
 217         } u;
 218         /*
 219          * "field" is only needed when nested under a variant, in which
 220          * case we cannot specialize the nested operations.
 221          */
 222         const struct lttng_event_field *field;
 223 };
 224
 225 struct estack_entry {
 226         enum entry_type type;   /* For dynamic typing. */
 227         union {
 228                 int64_t v;
 229                 double d;
 230
 231                 struct {
 232                         const char *str;
 233                         size_t seq_len;
 234                         enum estack_string_literal_type literal_type;
 235                 } s;
 236                 struct load_ptr ptr;
 237         } u;
 238 };
 239
 240 struct estack {
 241         int top;        /* top of stack */
 242         struct estack_entry e[FILTER_STACK_LEN];
 243 };
 244
 245 /*
 246  * Always use aliased type for ax/bx (top of stack).
 247  * When ax/bx are S64, use aliased value.
 248  */
 249 #define estack_ax_v     ax
 250 #define estack_bx_v     bx
 251 #define estack_ax_t     ax_t
 252 #define estack_bx_t     bx_t
 253
 254 /*
 255  * ax and bx registers can hold either integer, double or string.
 256  */
 257 #define estack_ax(stack, top)                                   \
 258         ({                                                      \
 259                 assert((top) > FILTER_STACK_EMPTY);             \
 260                 &(stack)->e[top];                               \
 261         })
 262
 263 #define estack_bx(stack, top)                                   \
 264         ({                                                      \
 265                 assert((top) > FILTER_STACK_EMPTY + 1);         \
 266                 &(stack)->e[(top) - 1];                         \
 267         })
 268
 269 /*
 270  * Currently, only integers (REG_S64) can be pushed into the stack.
 271  */
 272 #define estack_push(stack, top, ax, bx, ax_t, bx_t)             \
 273         do {                                                    \
 274                 assert((top) < FILTER_STACK_LEN - 1);           \
 275                 (stack)->e[(top) - 1].u.v = (bx);               \
 276                 (stack)->e[(top) - 1].type = (bx_t);            \
 277                 (bx) = (ax);                                    \
 278                 (bx_t) = (ax_t);                                \
 279                 ++(top);                                        \
 280         } while (0)
 281
 282 #define estack_pop(stack, top, ax, bx, ax_t, bx_t)              \
 283         do {                                                    \
 284                 assert((top) > FILTER_STACK_EMPTY);             \
 285                 (ax) = (bx);                                    \
 286                 (ax_t) = (bx_t);                                \
 287                 (bx) = (stack)->e[(top) - 2].u.v;               \
 288                 (bx_t) = (stack)->e[(top) - 2].type;            \
 289                 (top)--;                                        \
 290         } while (0)
 291
 292 const char *print_op(enum filter_op op);
 293
 294 int lttng_filter_validate_bytecode(struct bytecode_runtime *bytecode);
 295 int lttng_filter_specialize_bytecode(const struct lttng_event_desc *event_desc,
 296                 struct bytecode_runtime *bytecode);
 297
 298 uint64_t lttng_filter_false(void *filter_data,
 299                 const char *filter_stack_data);
 300 uint64_t lttng_filter_interpret_bytecode(void *filter_data,
 301                 const char *filter_stack_data);
 302
 303 #endif /* _LTTNG_FILTER_H */