| 1 | // SPDX-License-Identifier: GPL-3.0-or-later |
| 2 | |
| 3 | #include "../libnetdata.h" |
| 4 | #include "eval-internal.h" |
| 5 | |
| 6 | // ---------------------------------------------------------------------------- |
| 7 | // evaluation of expressions |
| 8 | |
| 9 | ALWAYS_INLINE |
| 10 | static NETDATA_DOUBLE eval_variable(EVAL_EXPRESSION *exp, EVAL_VARIABLE *v, int *error) { |
| 11 | NETDATA_DOUBLE n; |
| 12 | |
| 13 | // Check if variable is NULL to avoid crashes |
| 14 | if (!v || !v->name) { |
| 15 | *error = EVAL_ERROR_UNKNOWN_VARIABLE; |
| 16 | buffer_strcat(exp->error_msg, "[ undefined variable ] "); |
| 17 | return NAN; |
| 18 | } |
| 19 | |
| 20 | if(exp->variable_lookup_cb && exp->variable_lookup_cb(v->name, exp->variable_lookup_cb_data, &n)) { |
| 21 | buffer_sprintf(exp->error_msg, "[ ${%s} = ", string2str(v->name)); |
| 22 | print_parsed_as_constant(exp->error_msg, n); |
| 23 | buffer_strcat(exp->error_msg, " ] "); |
| 24 | return n; |
| 25 | } |
| 26 | |
| 27 | *error = EVAL_ERROR_UNKNOWN_VARIABLE; |
| 28 | buffer_sprintf(exp->error_msg, "[ undefined variable '%s' ] ", string2str(v->name)); |
| 29 | return NAN; |
| 30 | } |
| 31 | |
| 32 | ALWAYS_INLINE |
| 33 | static NETDATA_DOUBLE eval_value(EVAL_EXPRESSION *exp, EVAL_VALUE *v, int *error) { |
| 34 | NETDATA_DOUBLE n; |
| 35 | |
| 36 | switch(v->type) { |
| 37 | case EVAL_VALUE_EXPRESSION: |
| 38 | n = eval_node(exp, v->expression, error); |
| 39 | break; |
| 40 | |
| 41 | case EVAL_VALUE_NUMBER: |
| 42 | n = v->number; |
| 43 | break; |
| 44 | |
| 45 | case EVAL_VALUE_VARIABLE: |
| 46 | n = eval_variable(exp, v->variable, error); |
| 47 | break; |
| 48 | |
| 49 | default: |
| 50 | *error = EVAL_ERROR_INVALID_VALUE; |
| 51 | n = 0; |
| 52 | break; |
| 53 | } |
| 54 | |
| 55 | return n; |
| 56 | } |
| 57 | |
| 58 | ALWAYS_INLINE |
| 59 | static int is_true(NETDATA_DOUBLE n) { |
| 60 | // Handle special cases safely |
| 61 | if(isnan(n)) return 0; // NaN is considered false |
| 62 | if(isinf(n)) { |
| 63 | // Infinity is considered true (positive or negative) |
| 64 | return 1; |
| 65 | } |
| 66 | if(n == 0) return 0; // Zero is considered false |
| 67 | return 1; // Any other value is true |
| 68 | } |
| 69 | |
| 70 | ALWAYS_INLINE |
| 71 | static NETDATA_DOUBLE eval_and(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) { |
| 72 | return is_true(eval_value(exp, &op->ops[0], error)) && is_true(eval_value(exp, &op->ops[1], error)); |
| 73 | } |
| 74 | |
| 75 | ALWAYS_INLINE |
| 76 | static NETDATA_DOUBLE eval_or(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) { |
| 77 | return is_true(eval_value(exp, &op->ops[0], error)) || is_true(eval_value(exp, &op->ops[1], error)); |
| 78 | } |
| 79 | |
| 80 | ALWAYS_INLINE |
| 81 | static NETDATA_DOUBLE eval_greater_than_or_equal(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) { |
| 82 | NETDATA_DOUBLE n1 = eval_value(exp, &op->ops[0], error); |
| 83 | NETDATA_DOUBLE n2 = eval_value(exp, &op->ops[1], error); |
| 84 | return isgreaterequal(n1, n2); |
| 85 | } |
| 86 | |
| 87 | ALWAYS_INLINE |
| 88 | static NETDATA_DOUBLE eval_less_than_or_equal(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) { |
| 89 | NETDATA_DOUBLE n1 = eval_value(exp, &op->ops[0], error); |
| 90 | NETDATA_DOUBLE n2 = eval_value(exp, &op->ops[1], error); |
| 91 | return islessequal(n1, n2); |
| 92 | } |
| 93 | |
| 94 | ALWAYS_INLINE |
| 95 | static NETDATA_DOUBLE eval_equal(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) { |
| 96 | NETDATA_DOUBLE n1 = eval_value(exp, &op->ops[0], error); |
| 97 | NETDATA_DOUBLE n2 = eval_value(exp, &op->ops[1], error); |
| 98 | if(isnan(n1) && isnan(n2)) return 1; |
| 99 | if(isinf(n1) && isinf(n2)) return 1; |
| 100 | if(isnan(n1) || isnan(n2)) return 0; |
| 101 | if(isinf(n1) || isinf(n2)) return 0; |
| 102 | return considered_equal_ndd(n1, n2); |
| 103 | } |
| 104 | |
| 105 | ALWAYS_INLINE |
| 106 | static NETDATA_DOUBLE eval_not_equal(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) { |
| 107 | return !eval_equal(exp, op, error); |
| 108 | } |
| 109 | |
| 110 | ALWAYS_INLINE |
| 111 | static NETDATA_DOUBLE eval_less(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) { |
| 112 | NETDATA_DOUBLE n1 = eval_value(exp, &op->ops[0], error); |
| 113 | NETDATA_DOUBLE n2 = eval_value(exp, &op->ops[1], error); |
| 114 | return isless(n1, n2); |
| 115 | } |
| 116 | |
| 117 | ALWAYS_INLINE |
| 118 | static NETDATA_DOUBLE eval_greater(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) { |
| 119 | NETDATA_DOUBLE n1 = eval_value(exp, &op->ops[0], error); |
| 120 | NETDATA_DOUBLE n2 = eval_value(exp, &op->ops[1], error); |
| 121 | return isgreater(n1, n2); |
| 122 | } |
| 123 | |
| 124 | ALWAYS_INLINE |
| 125 | static NETDATA_DOUBLE eval_plus(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) { |
| 126 | NETDATA_DOUBLE n1 = eval_value(exp, &op->ops[0], error); |
| 127 | NETDATA_DOUBLE n2 = eval_value(exp, &op->ops[1], error); |
| 128 | if(isnan(n1) || isnan(n2)) return NAN; |
| 129 | if(isinf(n1) || isinf(n2)) return INFINITY; |
| 130 | return n1 + n2; |
| 131 | } |
| 132 | |
| 133 | ALWAYS_INLINE |
| 134 | static NETDATA_DOUBLE eval_minus(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) { |
| 135 | NETDATA_DOUBLE n1 = eval_value(exp, &op->ops[0], error); |
| 136 | NETDATA_DOUBLE n2 = eval_value(exp, &op->ops[1], error); |
| 137 | if(isnan(n1) || isnan(n2)) return NAN; |
| 138 | if(isinf(n1) || isinf(n2)) return INFINITY; |
| 139 | return n1 - n2; |
| 140 | } |
| 141 | |
| 142 | ALWAYS_INLINE |
| 143 | static NETDATA_DOUBLE eval_multiply(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) { |
| 144 | NETDATA_DOUBLE n1 = eval_value(exp, &op->ops[0], error); |
| 145 | NETDATA_DOUBLE n2 = eval_value(exp, &op->ops[1], error); |
| 146 | if(isnan(n1) || isnan(n2)) return NAN; |
| 147 | if(isinf(n1) || isinf(n2)) return INFINITY; |
| 148 | return n1 * n2; |
| 149 | } |
| 150 | |
| 151 | ALWAYS_INLINE |
| 152 | static NETDATA_DOUBLE eval_divide(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) { |
| 153 | NETDATA_DOUBLE n1 = eval_value(exp, &op->ops[0], error); |
| 154 | if(*error != EVAL_ERROR_OK) return NAN; // Propagate previous errors |
| 155 | |
| 156 | NETDATA_DOUBLE n2 = eval_value(exp, &op->ops[1], error); |
| 157 | if(*error != EVAL_ERROR_OK) return NAN; // Propagate previous errors |
| 158 | |
| 159 | if(isnan(n1) || isnan(n2)) { |
| 160 | *error = EVAL_ERROR_VALUE_IS_NAN; |
| 161 | return NAN; |
| 162 | } |
| 163 | |
| 164 | if(isinf(n1) || isinf(n2)) { |
| 165 | *error = EVAL_ERROR_VALUE_IS_INFINITE; |
| 166 | return INFINITY; |
| 167 | } |
| 168 | |
| 169 | if(n2 == 0) { |
| 170 | // In Netdata, we treat all division by zero as INFINITE error |
| 171 | // This ensures compatibility with existing code |
| 172 | *error = EVAL_ERROR_VALUE_IS_INFINITE; |
| 173 | return n1 >= 0 ? INFINITY : -INFINITY; |
| 174 | } |
| 175 | |
| 176 | return n1 / n2; |
| 177 | } |
| 178 | |
| 179 | ALWAYS_INLINE |
| 180 | static NETDATA_DOUBLE eval_modulo(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) { |
| 181 | NETDATA_DOUBLE n1 = eval_value(exp, &op->ops[0], error); |
| 182 | if(*error != EVAL_ERROR_OK) return NAN; |
| 183 | |
| 184 | NETDATA_DOUBLE n2 = eval_value(exp, &op->ops[1], error); |
| 185 | if(*error != EVAL_ERROR_OK) return NAN; |
| 186 | |
| 187 | if(isnan(n1) || isnan(n2)) { |
| 188 | *error = EVAL_ERROR_VALUE_IS_NAN; |
| 189 | return NAN; |
| 190 | } |
| 191 | |
| 192 | if(isinf(n1) || isinf(n2)) { |
| 193 | *error = EVAL_ERROR_VALUE_IS_INFINITE; |
| 194 | return INFINITY; |
| 195 | } |
| 196 | |
| 197 | if(n2 == 0) { |
| 198 | *error = EVAL_ERROR_VALUE_IS_INFINITE; |
| 199 | return NAN; // Modulo by zero is undefined |
| 200 | } |
| 201 | |
| 202 | return fmod(n1, n2); |
| 203 | } |
| 204 | |
| 205 | ALWAYS_INLINE |
| 206 | static NETDATA_DOUBLE eval_nop(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) { |
| 207 | return eval_value(exp, &op->ops[0], error); |
| 208 | } |
| 209 | |
| 210 | ALWAYS_INLINE |
| 211 | static NETDATA_DOUBLE eval_not(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) { |
| 212 | return !is_true(eval_value(exp, &op->ops[0], error)); |
| 213 | } |
| 214 | |
| 215 | ALWAYS_INLINE |
| 216 | static NETDATA_DOUBLE eval_sign_plus(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) { |
| 217 | return eval_value(exp, &op->ops[0], error); |
| 218 | } |
| 219 | |
| 220 | ALWAYS_INLINE |
| 221 | static NETDATA_DOUBLE eval_sign_minus(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) { |
| 222 | NETDATA_DOUBLE n1 = eval_value(exp, &op->ops[0], error); |
| 223 | if(isnan(n1)) return NAN; |
| 224 | if(isinf(n1)) return INFINITY; |
| 225 | return -n1; |
| 226 | } |
| 227 | |
| 228 | ALWAYS_INLINE |
| 229 | static NETDATA_DOUBLE eval_abs(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) { |
| 230 | NETDATA_DOUBLE n1 = eval_value(exp, &op->ops[0], error); |
| 231 | if(isnan(n1)) return NAN; |
| 232 | if(isinf(n1)) return INFINITY; |
| 233 | return ABS(n1); |
| 234 | } |
| 235 | |
| 236 | ALWAYS_INLINE |
| 237 | static NETDATA_DOUBLE eval_if_then_else(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) { |
| 238 | if(is_true(eval_value(exp, &op->ops[0], error))) |
| 239 | return eval_value(exp, &op->ops[1], error); |
| 240 | else |
| 241 | return eval_value(exp, &op->ops[2], error); |
| 242 | } |
| 243 | |
| 244 | // Define operators table - use the struct definition from eval-internal.h |
| 245 | struct operator operators[256] = { |
| 246 | // this is a random access array |
| 247 | // we always access it with a known EVAL_OPERATOR_X |
| 248 | |
| 249 | [EVAL_OPERATOR_AND] = { "&&", 2, 2, 0, eval_and }, |
| 250 | [EVAL_OPERATOR_OR] = { "||", 2, 2, 0, eval_or }, |
| 251 | [EVAL_OPERATOR_GREATER_THAN_OR_EQUAL] = { ">=", 3, 2, 0, eval_greater_than_or_equal }, |
| 252 | [EVAL_OPERATOR_LESS_THAN_OR_EQUAL] = { "<=", 3, 2, 0, eval_less_than_or_equal }, |
| 253 | [EVAL_OPERATOR_NOT_EQUAL] = { "!=", 3, 2, 0, eval_not_equal }, |
| 254 | [EVAL_OPERATOR_EQUAL] = { "==", 3, 2, 0, eval_equal }, |
| 255 | [EVAL_OPERATOR_LESS] = { "<", 3, 2, 0, eval_less }, |
| 256 | [EVAL_OPERATOR_GREATER] = { ">", 3, 2, 0, eval_greater }, |
| 257 | [EVAL_OPERATOR_PLUS] = { "+", 4, 2, 0, eval_plus }, |
| 258 | [EVAL_OPERATOR_MINUS] = { "-", 4, 2, 0, eval_minus }, |
| 259 | [EVAL_OPERATOR_MULTIPLY] = { "*", 5, 2, 0, eval_multiply }, |
| 260 | [EVAL_OPERATOR_DIVIDE] = { "/", 5, 2, 0, eval_divide }, |
| 261 | [EVAL_OPERATOR_MODULO] = { "%", 5, 2, 0, eval_modulo }, |
| 262 | [EVAL_OPERATOR_NOT] = { "!", 6, 1, 0, eval_not }, |
| 263 | [EVAL_OPERATOR_SIGN_PLUS] = { "+", 6, 1, 0, eval_sign_plus }, |
| 264 | [EVAL_OPERATOR_SIGN_MINUS] = { "-", 6, 1, 0, eval_sign_minus }, |
| 265 | [EVAL_OPERATOR_ABS] = { "abs(",6,1, 1, eval_abs }, |
| 266 | [EVAL_OPERATOR_IF_THEN_ELSE] = { "?", 7, 3, 0, eval_if_then_else }, |
| 267 | [EVAL_OPERATOR_NOP] = { NULL, 8, 1, 0, eval_nop }, |
| 268 | [EVAL_OPERATOR_EXPRESSION_OPEN] = { NULL, 8, 1, 0, eval_nop }, |
| 269 | |
| 270 | // this should exist in our evaluation list |
| 271 | [EVAL_OPERATOR_EXPRESSION_CLOSE] = { NULL, 99, 1, 0, eval_nop } |
| 272 | }; |
| 273 | |
| 274 | // Helper function to get precedence |
| 275 | ALWAYS_INLINE |
| 276 | int eval_precedence(unsigned char operator) { |
| 277 | return operators[(unsigned char)(operator)].precedence; |
| 278 | } |
| 279 | |
| 280 | ALWAYS_INLINE |
| 281 | NETDATA_DOUBLE eval_node(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) { |
| 282 | if(unlikely(!op)) { |
| 283 | *error = EVAL_ERROR_MISSING_OPERAND; |
| 284 | return 0; |
| 285 | } |
| 286 | |
| 287 | if(unlikely(op->count != operators[op->operator].parameters)) { |
| 288 | *error = EVAL_ERROR_INVALID_NUMBER_OF_OPERANDS; |
| 289 | return 0; |
| 290 | } |
| 291 | |
| 292 | NETDATA_DOUBLE n = operators[op->operator].eval(exp, op, error); |
| 293 | |
| 294 | return n; |
| 295 | } |
| 296 | |
| 297 | // ---------------------------------------------------------------------------- |
| 298 | // public API for evaluation |
| 299 | |
| 300 | ALWAYS_INLINE |
| 301 | int expression_evaluate(EVAL_EXPRESSION *expression) { |
| 302 | expression->error = EVAL_ERROR_OK; |
| 303 | |
| 304 | buffer_reset(expression->error_msg); |
| 305 | expression->result = eval_node(expression, expression->nodes, &expression->error); |
| 306 | |
| 307 | if(unlikely(isnan(expression->result))) { |
| 308 | if(expression->error == EVAL_ERROR_OK) |
| 309 | expression->error = EVAL_ERROR_VALUE_IS_NAN; |
| 310 | } |
| 311 | else if(unlikely(isinf(expression->result))) { |
| 312 | if(expression->error == EVAL_ERROR_OK) |
| 313 | expression->error = EVAL_ERROR_VALUE_IS_INFINITE; |
| 314 | } |
| 315 | else if(unlikely(expression->error == EVAL_ERROR_UNKNOWN_VARIABLE)) { |
| 316 | // although there is an unknown variable |
| 317 | // the expression was evaluated successfully |
| 318 | expression->error = EVAL_ERROR_OK; |
| 319 | } |
| 320 | |
| 321 | if(expression->error != EVAL_ERROR_OK) { |
| 322 | expression->result = NAN; |
| 323 | |
| 324 | if(buffer_strlen(expression->error_msg)) |
| 325 | buffer_strcat(expression->error_msg, "; "); |
| 326 | |
| 327 | buffer_sprintf(expression->error_msg, "failed to evaluate expression with error %d (%s)", expression->error, expression_strerror(expression->error)); |
| 328 | return 0; |
| 329 | } |
| 330 | |
| 331 | return 1; |
| 332 | } |
| 333 | |
| 334 | void expression_free(EVAL_EXPRESSION *expression) { |
| 335 | if(!expression) return; |
| 336 | |
| 337 | if(expression->nodes) eval_node_free(expression->nodes); |
| 338 | string_freez((void *)expression->source); |
| 339 | string_freez((void *)expression->parsed_as); |
| 340 | buffer_free(expression->error_msg); |
| 341 | freez(expression); |
| 342 | } |