expr.c revision 1.11
1 /* $NetBSD: expr.c,v 1.11 2017/07/01 23:12:08 joerg Exp $ */ 2 3 /* 4 * Korn expression evaluation 5 */ 6 /* 7 * todo: better error handling: if in builtin, should be builtin error, etc. 8 */ 9 #include <sys/cdefs.h> 10 11 #ifndef lint 12 __RCSID("$NetBSD: expr.c,v 1.11 2017/07/01 23:12:08 joerg Exp $"); 13 #endif 14 15 16 #include "sh.h" 17 #include <ctype.h> 18 #include <stdbool.h> 19 20 /* The order of these enums is constrained by the order of opinfo[] */ 21 enum token { 22 /* some (long) unary operators */ 23 O_PLUSPLUS = 0, O_MINUSMINUS, 24 /* binary operators */ 25 O_EQ, O_NE, 26 /* assignments are assumed to be in range O_ASN .. O_BORASN */ 27 O_ASN, O_TIMESASN, O_DIVASN, O_MODASN, O_PLUSASN, O_MINUSASN, 28 O_LSHIFTASN, O_RSHIFTASN, O_BANDASN, O_BXORASN, O_BORASN, 29 O_LSHIFT, O_RSHIFT, 30 O_LE, O_GE, O_LT, O_GT, 31 O_LAND, 32 O_LOR, 33 O_TIMES, O_DIV, O_MOD, 34 O_PLUS, O_MINUS, 35 O_BAND, 36 O_BXOR, 37 O_BOR, 38 O_TERN, 39 O_COMMA, 40 /* things after this aren't used as binary operators */ 41 /* unary that are not also binaries */ 42 O_BNOT, O_LNOT, 43 /* misc */ 44 OPEN_PAREN, CLOSE_PAREN, CTERN, 45 /* things that don't appear in the opinfo[] table */ 46 VAR, LIT, END, BAD 47 }; 48 #define IS_BINOP(op) (((int)op) >= (int)O_EQ && ((int)op) <= (int)O_COMMA) 49 #define IS_ASSIGNOP(op) ((int)(op) >= (int)O_ASN && (int)(op) <= (int)O_BORASN) 50 51 enum prec { 52 P_PRIMARY = 0, /* VAR, LIT, (), ~ ! - + */ 53 P_MULT, /* * / % */ 54 P_ADD, /* + - */ 55 P_SHIFT, /* << >> */ 56 P_RELATION, /* < <= > >= */ 57 P_EQUALITY, /* == != */ 58 P_BAND, /* & */ 59 P_BXOR, /* ^ */ 60 P_BOR, /* | */ 61 P_LAND, /* && */ 62 P_LOR, /* || */ 63 P_TERN, /* ?: */ 64 P_ASSIGN, /* = *= /= %= += -= <<= >>= &= ^= |= */ 65 P_COMMA /* , */ 66 }; 67 #define MAX_PREC P_COMMA 68 69 struct opinfo { 70 char name[4]; 71 int len; /* name length */ 72 enum prec prec; /* precedence: lower is higher */ 73 }; 74 75 /* Tokens in this table must be ordered so the longest are first 76 * (eg, += before +). If you change something, change the order 77 * of enum token too. 78 */ 79 static const struct opinfo opinfo[] = { 80 { "++", 2, P_PRIMARY }, /* before + */ 81 { "--", 2, P_PRIMARY }, /* before - */ 82 { "==", 2, P_EQUALITY }, /* before = */ 83 { "!=", 2, P_EQUALITY }, /* before ! */ 84 { "=", 1, P_ASSIGN }, /* keep assigns in a block */ 85 { "*=", 2, P_ASSIGN }, 86 { "/=", 2, P_ASSIGN }, 87 { "%=", 2, P_ASSIGN }, 88 { "+=", 2, P_ASSIGN }, 89 { "-=", 2, P_ASSIGN }, 90 { "<<=", 3, P_ASSIGN }, 91 { ">>=", 3, P_ASSIGN }, 92 { "&=", 2, P_ASSIGN }, 93 { "^=", 2, P_ASSIGN }, 94 { "|=", 2, P_ASSIGN }, 95 { "<<", 2, P_SHIFT }, 96 { ">>", 2, P_SHIFT }, 97 { "<=", 2, P_RELATION }, 98 { ">=", 2, P_RELATION }, 99 { "<", 1, P_RELATION }, 100 { ">", 1, P_RELATION }, 101 { "&&", 2, P_LAND }, 102 { "||", 2, P_LOR }, 103 { "*", 1, P_MULT }, 104 { "/", 1, P_MULT }, 105 { "%", 1, P_MULT }, 106 { "+", 1, P_ADD }, 107 { "-", 1, P_ADD }, 108 { "&", 1, P_BAND }, 109 { "^", 1, P_BXOR }, 110 { "|", 1, P_BOR }, 111 { "?", 1, P_TERN }, 112 { ",", 1, P_COMMA }, 113 { "~", 1, P_PRIMARY }, 114 { "!", 1, P_PRIMARY }, 115 { "(", 1, P_PRIMARY }, 116 { ")", 1, P_PRIMARY }, 117 { ":", 1, P_PRIMARY }, 118 { "", 0, P_PRIMARY } /* end of table */ 119 }; 120 121 122 typedef struct expr_state Expr_state; 123 struct expr_state { 124 const char *expression; /* expression being evaluated */ 125 const char *tokp; /* lexical position */ 126 enum token tok; /* token from token() */ 127 int noassign; /* don't do assigns (for ?:,&&,||) */ 128 struct tbl *val; /* value from token() */ 129 struct tbl *evaling; /* variable that is being recursively 130 * expanded (EXPRINEVAL flag set) 131 */ 132 }; 133 134 enum error_type { ET_UNEXPECTED, ET_BADLIT, ET_RECURSIVE, 135 ET_LVALUE, ET_RDONLY, ET_STR }; 136 137 static void evalerr ARGS((Expr_state *es, enum error_type type, 138 const char *str)) GCC_FUNC_ATTR(noreturn); 139 static struct tbl *evalexpr ARGS((Expr_state *es, enum prec prec)); 140 static void token ARGS((Expr_state *es)); 141 static struct tbl *do_ppmm(Expr_state *, enum token, struct tbl *, bool); 142 static void assign_check ARGS((Expr_state *es, enum token op, 143 struct tbl *vasn)); 144 static struct tbl *tempvar ARGS((void)); 145 static struct tbl *intvar ARGS((Expr_state *es, struct tbl *vp)); 146 147 /* 148 * parse and evaluate expression 149 */ 150 int 151 evaluate(expr, rval, error_ok) 152 const char *expr; 153 long *rval; 154 int error_ok; 155 { 156 struct tbl v; 157 int ret; 158 159 v.flag = DEFINED|INTEGER; 160 v.type = 0; 161 ret = v_evaluate(&v, expr, error_ok); 162 *rval = v.val.i; 163 return ret; 164 } 165 166 /* 167 * parse and evaluate expression, storing result in vp. 168 */ 169 int 170 v_evaluate(vp, expr, error_ok) 171 struct tbl *vp; 172 const char *expr; 173 volatile int error_ok; 174 { 175 struct tbl *v; 176 Expr_state curstate; 177 Expr_state * const es = &curstate; 178 int i; 179 180 /* save state to allow recursive calls */ 181 curstate.expression = curstate.tokp = expr; 182 curstate.noassign = 0; 183 curstate.evaling = (struct tbl *) 0; 184 185 newenv(E_ERRH); 186 i = ksh_sigsetjmp(e->jbuf, 0); 187 if (i) { 188 /* Clear EXPRINEVAL in of any variables we were playing with */ 189 if (curstate.evaling) 190 curstate.evaling->flag &= ~EXPRINEVAL; 191 quitenv(); 192 if (i == LAEXPR) { 193 if (error_ok == KSH_RETURN_ERROR) 194 return 0; 195 errorf("%s", null); 196 } 197 unwind(i); 198 /*NOTREACHED*/ 199 } 200 201 token(es); 202 #if 1 /* ifdef-out to disallow empty expressions to be treated as 0 */ 203 if (es->tok == END) { 204 es->tok = LIT; 205 es->val = tempvar(); 206 } 207 #endif /* 0 */ 208 v = intvar(es, evalexpr(es, MAX_PREC)); 209 210 if (es->tok != END) 211 evalerr(es, ET_UNEXPECTED, (char *) 0); 212 213 if (vp->flag & INTEGER) 214 setint_v(vp, v); 215 else 216 /* can fail if readonly */ 217 setstr(vp, str_val(v), error_ok); 218 219 quitenv(); 220 221 return 1; 222 } 223 224 static void 225 evalerr(es, type, str) 226 Expr_state *es; 227 enum error_type type; 228 const char *str; 229 { 230 char tbuf[2]; 231 const char *s; 232 233 switch (type) { 234 case ET_UNEXPECTED: 235 switch (es->tok) { 236 case VAR: 237 s = es->val->name; 238 break; 239 case LIT: 240 s = str_val(es->val); 241 break; 242 case END: 243 s = "end of expression"; 244 break; 245 case BAD: 246 tbuf[0] = *es->tokp; 247 tbuf[1] = '\0'; 248 s = tbuf; 249 break; 250 default: 251 s = opinfo[(int)es->tok].name; 252 } 253 warningf(true, "%s: unexpected `%s'", es->expression, s); 254 break; 255 256 case ET_BADLIT: 257 warningf(true, "%s: bad number `%s'", es->expression, str); 258 break; 259 260 case ET_RECURSIVE: 261 warningf(true, "%s: expression recurses on parameter `%s'", 262 es->expression, str); 263 break; 264 265 case ET_LVALUE: 266 warningf(true, "%s: %s requires lvalue", 267 es->expression, str); 268 break; 269 270 case ET_RDONLY: 271 warningf(true, "%s: %s applied to read only variable", 272 es->expression, str); 273 break; 274 275 default: /* keep gcc happy */ 276 case ET_STR: 277 warningf(true, "%s: %s", es->expression, str); 278 break; 279 } 280 unwind(LAEXPR); 281 } 282 283 static struct tbl * 284 evalexpr(es, prec) 285 Expr_state *es; 286 enum prec prec; 287 { 288 struct tbl *vl, UNINITIALIZED(*vr), *vasn; 289 enum token op; 290 long UNINITIALIZED(res); 291 292 if (prec == P_PRIMARY) { 293 op = es->tok; 294 if (op == O_BNOT || op == O_LNOT || op == O_MINUS 295 || op == O_PLUS) 296 { 297 token(es); 298 vl = intvar(es, evalexpr(es, P_PRIMARY)); 299 if (op == O_BNOT) 300 vl->val.i = ~vl->val.i; 301 else if (op == O_LNOT) 302 vl->val.i = !vl->val.i; 303 else if (op == O_MINUS) 304 vl->val.i = -vl->val.i; 305 /* op == O_PLUS is a no-op */ 306 } else if (op == OPEN_PAREN) { 307 token(es); 308 vl = evalexpr(es, MAX_PREC); 309 if (es->tok != CLOSE_PAREN) 310 evalerr(es, ET_STR, "missing )"); 311 token(es); 312 } else if (op == O_PLUSPLUS || op == O_MINUSMINUS) { 313 token(es); 314 vl = do_ppmm(es, op, es->val, true); 315 token(es); 316 } else if (op == VAR || op == LIT) { 317 vl = es->val; 318 token(es); 319 } else { 320 evalerr(es, ET_UNEXPECTED, (char *) 0); 321 /*NOTREACHED*/ 322 } 323 if (es->tok == O_PLUSPLUS || es->tok == O_MINUSMINUS) { 324 vl = do_ppmm(es, es->tok, vl, false); 325 token(es); 326 } 327 return vl; 328 } 329 vl = evalexpr(es, ((int) prec) - 1); 330 for (op = es->tok; IS_BINOP(op) && opinfo[(int) op].prec == prec; 331 op = es->tok) 332 { 333 token(es); 334 vasn = vl; 335 if (op != O_ASN) /* vl may not have a value yet */ 336 vl = intvar(es, vl); 337 if (IS_ASSIGNOP(op)) { 338 assign_check(es, op, vasn); 339 vr = intvar(es, evalexpr(es, P_ASSIGN)); 340 } else if (op != O_TERN && op != O_LAND && op != O_LOR) 341 vr = intvar(es, evalexpr(es, ((int) prec) - 1)); 342 if ((op == O_DIV || op == O_MOD || op == O_DIVASN 343 || op == O_MODASN) && vr->val.i == 0) 344 { 345 if (es->noassign) 346 vr->val.i = 1; 347 else 348 evalerr(es, ET_STR, "zero divisor"); 349 } 350 switch ((int) op) { 351 case O_TIMES: 352 case O_TIMESASN: 353 res = vl->val.i * vr->val.i; 354 break; 355 case O_DIV: 356 case O_DIVASN: 357 res = vl->val.i / vr->val.i; 358 break; 359 case O_MOD: 360 case O_MODASN: 361 res = vl->val.i % vr->val.i; 362 break; 363 case O_PLUS: 364 case O_PLUSASN: 365 res = vl->val.i + vr->val.i; 366 break; 367 case O_MINUS: 368 case O_MINUSASN: 369 res = vl->val.i - vr->val.i; 370 break; 371 case O_LSHIFT: 372 case O_LSHIFTASN: 373 res = vl->val.i << vr->val.i; 374 break; 375 case O_RSHIFT: 376 case O_RSHIFTASN: 377 res = vl->val.i >> vr->val.i; 378 break; 379 case O_LT: 380 res = vl->val.i < vr->val.i; 381 break; 382 case O_LE: 383 res = vl->val.i <= vr->val.i; 384 break; 385 case O_GT: 386 res = vl->val.i > vr->val.i; 387 break; 388 case O_GE: 389 res = vl->val.i >= vr->val.i; 390 break; 391 case O_EQ: 392 res = vl->val.i == vr->val.i; 393 break; 394 case O_NE: 395 res = vl->val.i != vr->val.i; 396 break; 397 case O_BAND: 398 case O_BANDASN: 399 res = vl->val.i & vr->val.i; 400 break; 401 case O_BXOR: 402 case O_BXORASN: 403 res = vl->val.i ^ vr->val.i; 404 break; 405 case O_BOR: 406 case O_BORASN: 407 res = vl->val.i | vr->val.i; 408 break; 409 case O_LAND: 410 if (!vl->val.i) 411 es->noassign++; 412 vr = intvar(es, evalexpr(es, ((int) prec) - 1)); 413 res = vl->val.i && vr->val.i; 414 if (!vl->val.i) 415 es->noassign--; 416 break; 417 case O_LOR: 418 if (vl->val.i) 419 es->noassign++; 420 vr = intvar(es, evalexpr(es, ((int) prec) - 1)); 421 res = vl->val.i || vr->val.i; 422 if (vl->val.i) 423 es->noassign--; 424 break; 425 case O_TERN: 426 { 427 int ex = vl->val.i != 0; 428 if (!ex) 429 es->noassign++; 430 vl = evalexpr(es, MAX_PREC); 431 if (!ex) 432 es->noassign--; 433 if (es->tok != CTERN) 434 evalerr(es, ET_STR, "missing :"); 435 token(es); 436 if (ex) 437 es->noassign++; 438 vr = evalexpr(es, P_TERN); 439 if (ex) 440 es->noassign--; 441 vl = ex ? vl : vr; 442 } 443 break; 444 case O_ASN: 445 res = vr->val.i; 446 break; 447 case O_COMMA: 448 res = vr->val.i; 449 break; 450 } 451 if (IS_ASSIGNOP(op)) { 452 vr->val.i = res; 453 if (vasn->flag & INTEGER) 454 setint_v(vasn, vr); 455 else 456 setint(vasn, res); 457 vl = vr; 458 } else if (op != O_TERN) 459 vl->val.i = res; 460 } 461 return vl; 462 } 463 464 static void 465 token(es) 466 Expr_state *es; 467 { 468 const char *cp; 469 int c; 470 char *tvar; 471 472 /* skip white space */ 473 for (cp = es->tokp; (c = *cp), isspace((unsigned char)c); cp++) 474 ; 475 es->tokp = cp; 476 477 if (c == '\0') 478 es->tok = END; 479 else if (letter(c)) { 480 for (; letnum(c); c = *cp) 481 cp++; 482 if (c == '[') { 483 int len; 484 485 len = array_ref_len(cp); 486 if (len == 0) 487 evalerr(es, ET_STR, "missing ]"); 488 cp += len; 489 } 490 #ifdef KSH 491 else if (c == '(' /*)*/ ) { 492 /* todo: add math functions (all take single argument): 493 * abs acos asin atan cos cosh exp int log sin sinh sqrt 494 * tan tanh 495 */ 496 ; 497 } 498 #endif /* KSH */ 499 if (es->noassign) { 500 es->val = tempvar(); 501 es->val->flag |= EXPRLVALUE; 502 } else { 503 tvar = str_nsave(es->tokp, cp - es->tokp, ATEMP); 504 es->val = global(tvar); 505 afree(tvar, ATEMP); 506 } 507 es->tok = VAR; 508 } else if (digit(c)) { 509 for (; c != '_' && (letnum(c) || c == '#'); c = *cp++) 510 ; 511 tvar = str_nsave(es->tokp, --cp - es->tokp, ATEMP); 512 es->val = tempvar(); 513 es->val->flag &= ~INTEGER; 514 es->val->type = 0; 515 es->val->val.s = tvar; 516 if (setint_v(es->val, es->val) == NULL) 517 evalerr(es, ET_BADLIT, tvar); 518 afree(tvar, ATEMP); 519 es->tok = LIT; 520 } else { 521 int i, n0; 522 523 for (i = 0; (n0 = opinfo[i].name[0]); i++) 524 if (c == n0 525 && strncmp(cp, opinfo[i].name, opinfo[i].len) == 0) 526 { 527 es->tok = (enum token) i; 528 cp += opinfo[i].len; 529 break; 530 } 531 if (!n0) 532 es->tok = BAD; 533 } 534 es->tokp = cp; 535 } 536 537 /* Do a ++ or -- operation */ 538 static struct tbl * 539 do_ppmm(Expr_state *es, enum token op, struct tbl *vasn, bool is_prefix) 540 { 541 struct tbl *vl; 542 int oval; 543 544 assign_check(es, op, vasn); 545 546 vl = intvar(es, vasn); 547 oval = op == O_PLUSPLUS ? vl->val.i++ : vl->val.i--; 548 if (vasn->flag & INTEGER) 549 setint_v(vasn, vl); 550 else 551 setint(vasn, vl->val.i); 552 if (!is_prefix) /* undo the inc/dec */ 553 vl->val.i = oval; 554 555 return vl; 556 } 557 558 static void 559 assign_check(es, op, vasn) 560 Expr_state *es; 561 enum token op; 562 struct tbl *vasn; 563 { 564 if (vasn->name[0] == '\0' && !(vasn->flag & EXPRLVALUE)) 565 evalerr(es, ET_LVALUE, opinfo[(int) op].name); 566 else if (vasn->flag & RDONLY) 567 evalerr(es, ET_RDONLY, opinfo[(int) op].name); 568 } 569 570 static struct tbl * 571 tempvar() 572 { 573 register struct tbl *vp; 574 575 vp = (struct tbl*) alloc(sizeof(struct tbl), ATEMP); 576 vp->flag = ISSET|INTEGER; 577 vp->type = 0; 578 vp->areap = ATEMP; 579 vp->val.i = 0; 580 vp->name[0] = '\0'; 581 return vp; 582 } 583 584 /* cast (string) variable to temporary integer variable */ 585 static struct tbl * 586 intvar(es, vp) 587 Expr_state *es; 588 struct tbl *vp; 589 { 590 struct tbl *vq; 591 592 /* try to avoid replacing a temp var with another temp var */ 593 if (vp->name[0] == '\0' 594 && (vp->flag & (ISSET|INTEGER|EXPRLVALUE)) == (ISSET|INTEGER)) 595 return vp; 596 597 vq = tempvar(); 598 if (setint_v(vq, vp) == NULL) { 599 if (vp->flag & EXPRINEVAL) 600 evalerr(es, ET_RECURSIVE, vp->name); 601 es->evaling = vp; 602 vp->flag |= EXPRINEVAL; 603 v_evaluate(vq, str_val(vp), KSH_UNWIND_ERROR); 604 vp->flag &= ~EXPRINEVAL; 605 es->evaling = (struct tbl *) 0; 606 } 607 return vq; 608 } 609
Indexes created Tue Sep 23 14:10:03 GMT 2025