| 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_STAR_GLOB_STRING, |
| 87 | REG_UNKNOWN, |
| 88 | }; |
| 89 | |
| 90 | /* Validation stack */ |
| 91 | struct vstack_entry { |
| 92 | enum entry_type type; |
| 93 | }; |
| 94 | |
| 95 | struct vstack { |
| 96 | int top; /* top of stack */ |
| 97 | struct vstack_entry e[FILTER_STACK_LEN]; |
| 98 | }; |
| 99 | |
| 100 | static inline |
| 101 | void vstack_init(struct vstack *stack) |
| 102 | { |
| 103 | stack->top = -1; |
| 104 | } |
| 105 | |
| 106 | static inline |
| 107 | struct vstack_entry *vstack_ax(struct vstack *stack) |
| 108 | { |
| 109 | if (unlikely(stack->top < 0)) |
| 110 | return NULL; |
| 111 | return &stack->e[stack->top]; |
| 112 | } |
| 113 | |
| 114 | static inline |
| 115 | struct vstack_entry *vstack_bx(struct vstack *stack) |
| 116 | { |
| 117 | if (unlikely(stack->top < 1)) |
| 118 | return NULL; |
| 119 | return &stack->e[stack->top - 1]; |
| 120 | } |
| 121 | |
| 122 | static inline |
| 123 | int vstack_push(struct vstack *stack) |
| 124 | { |
| 125 | if (stack->top >= FILTER_STACK_LEN - 1) { |
| 126 | ERR("Stack full\n"); |
| 127 | return -EINVAL; |
| 128 | } |
| 129 | ++stack->top; |
| 130 | return 0; |
| 131 | } |
| 132 | |
| 133 | static inline |
| 134 | int vstack_pop(struct vstack *stack) |
| 135 | { |
| 136 | if (unlikely(stack->top < 0)) { |
| 137 | ERR("Stack empty\n"); |
| 138 | return -EINVAL; |
| 139 | } |
| 140 | stack->top--; |
| 141 | return 0; |
| 142 | } |
| 143 | |
| 144 | /* Execution stack */ |
| 145 | enum estack_string_literal_type { |
| 146 | ESTACK_STRING_LITERAL_TYPE_NONE, |
| 147 | ESTACK_STRING_LITERAL_TYPE_PLAIN, |
| 148 | ESTACK_STRING_LITERAL_TYPE_STAR_GLOB, |
| 149 | }; |
| 150 | |
| 151 | struct estack_entry { |
| 152 | enum entry_type type; /* For dynamic typing. */ |
| 153 | union { |
| 154 | int64_t v; |
| 155 | double d; |
| 156 | |
| 157 | struct { |
| 158 | const char *str; |
| 159 | size_t seq_len; |
| 160 | enum estack_string_literal_type literal_type; |
| 161 | } s; |
| 162 | } u; |
| 163 | }; |
| 164 | |
| 165 | struct estack { |
| 166 | int top; /* top of stack */ |
| 167 | struct estack_entry e[FILTER_STACK_LEN]; |
| 168 | }; |
| 169 | |
| 170 | /* |
| 171 | * Always use aliased type for ax/bx (top of stack). |
| 172 | * When ax/bx are S64, use aliased value. |
| 173 | */ |
| 174 | #define estack_ax_v ax |
| 175 | #define estack_bx_v bx |
| 176 | #define estack_ax_t ax_t |
| 177 | #define estack_bx_t bx_t |
| 178 | |
| 179 | /* |
| 180 | * ax and bx registers can hold either integer, double or string. |
| 181 | */ |
| 182 | #define estack_ax(stack, top) \ |
| 183 | ({ \ |
| 184 | assert((top) > FILTER_STACK_EMPTY); \ |
| 185 | &(stack)->e[top]; \ |
| 186 | }) |
| 187 | |
| 188 | #define estack_bx(stack, top) \ |
| 189 | ({ \ |
| 190 | assert((top) > FILTER_STACK_EMPTY + 1); \ |
| 191 | &(stack)->e[(top) - 1]; \ |
| 192 | }) |
| 193 | |
| 194 | /* |
| 195 | * Currently, only integers (REG_S64) can be pushed into the stack. |
| 196 | */ |
| 197 | #define estack_push(stack, top, ax, bx, ax_t, bx_t) \ |
| 198 | do { \ |
| 199 | assert((top) < FILTER_STACK_LEN - 1); \ |
| 200 | (stack)->e[(top) - 1].u.v = (bx); \ |
| 201 | (stack)->e[(top) - 1].type = (bx_t); \ |
| 202 | (bx) = (ax); \ |
| 203 | (bx_t) = (ax_t); \ |
| 204 | ++(top); \ |
| 205 | } while (0) |
| 206 | |
| 207 | #define estack_pop(stack, top, ax, bx, ax_t, bx_t) \ |
| 208 | do { \ |
| 209 | assert((top) > FILTER_STACK_EMPTY); \ |
| 210 | (ax) = (bx); \ |
| 211 | (ax_t) = (bx_t); \ |
| 212 | (bx) = (stack)->e[(top) - 2].u.v; \ |
| 213 | (bx_t) = (stack)->e[(top) - 2].type; \ |
| 214 | (top)--; \ |
| 215 | } while (0) |
| 216 | |
| 217 | const char *print_op(enum filter_op op); |
| 218 | |
| 219 | int lttng_filter_validate_bytecode(struct bytecode_runtime *bytecode); |
| 220 | int lttng_filter_specialize_bytecode(struct bytecode_runtime *bytecode); |
| 221 | |
| 222 | uint64_t lttng_filter_false(void *filter_data, |
| 223 | const char *filter_stack_data); |
| 224 | uint64_t lttng_filter_interpret_bytecode(void *filter_data, |
| 225 | const char *filter_stack_data); |
| 226 | |
| 227 | #endif /* _LTTNG_FILTER_H */ |