1 /* $NetBSD: chk.c,v 1.68 2024/11/30 18:17:11 rillig Exp $ */ 2 3 /* 4 * Copyright (c) 1996 Christopher G. Demetriou. All Rights Reserved. 5 * Copyright (c) 1994, 1995 Jochen Pohl 6 * All Rights Reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by Jochen Pohl for 19 * The NetBSD Project. 20 * 4. The name of the author may not be used to endorse or promote products 21 * derived from this software without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 33 */ 34 35 #if HAVE_NBTOOL_CONFIG_H 36 #include "nbtool_config.h" 37 #endif 38 39 #include <sys/cdefs.h> 40 #if defined(__RCSID) 41 __RCSID("$NetBSD: chk.c,v 1.68 2024/11/30 18:17:11 rillig Exp $"); 42 #endif 43 44 #include <ctype.h> 45 #include <limits.h> 46 #include <stdlib.h> 47 #include <string.h> 48 49 #include "lint2.h" 50 51 static void check_used_not_defined(const hte_t *); 52 static void check_defined_not_used(const hte_t *); 53 static void check_declared_not_used_or_defined(const hte_t *); 54 static void check_multiple_definitions(const hte_t *); 55 static void chkvtui(const hte_t *, sym_t *, sym_t *); 56 static void chkvtdi(const hte_t *, sym_t *, sym_t *); 57 static void chkfaui(const hte_t *, sym_t *, sym_t *); 58 static void chkau(const hte_t *, int, sym_t *, sym_t *, pos_t *, 59 fcall_t *, fcall_t *, type_t *, type_t *); 60 static void check_return_values(const hte_t *, sym_t *); 61 static void check_argument_declarations(const hte_t *, sym_t *, sym_t *); 62 static void printflike(const hte_t *, fcall_t *, int, const char *, type_t **); 63 static void scanflike(const hte_t *, fcall_t *, int, const char *, type_t **); 64 static void bad_format_string(const hte_t *, fcall_t *); 65 static void inconsistent_arguments(const hte_t *, fcall_t *, int); 66 static void too_few_arguments(const hte_t *, fcall_t *); 67 static void too_many_arguments(const hte_t *, fcall_t *); 68 static bool types_compatible(type_t *, type_t *, bool, bool, bool, bool *); 69 static bool prototypes_compatible(type_t *, type_t *, bool *); 70 static bool matches_no_arg_function(type_t *, bool *); 71 72 73 /* 74 * If there is a symbol named "main", mark it as used. 75 */ 76 void 77 mark_main_as_used(void) 78 { 79 hte_t *hte; 80 81 if ((hte = htab_search("main", false)) != NULL) 82 hte->h_used = true; 83 } 84 85 /* 86 * Performs all tests for a single name 87 */ 88 void 89 check_name(const hte_t *hte) 90 { 91 sym_t *sym, *def, *pdecl, *decl; 92 93 if (!uflag) { 94 check_used_not_defined(hte); 95 check_defined_not_used(hte); 96 if (xflag) 97 check_declared_not_used_or_defined(hte); 98 } 99 check_multiple_definitions(hte); 100 101 /* Get definition, prototype declaration and declaration */ 102 def = pdecl = decl = NULL; 103 for (sym = hte->h_syms; sym != NULL; sym = sym->s_next) { 104 if (def == NULL && (sym->s_def == DEF || sym->s_def == TDEF)) 105 def = sym; 106 if (pdecl == NULL && sym->s_def == DECL && 107 TP(sym->s_type)->t_tspec == FUNC && 108 TP(sym->s_type)->t_proto) { 109 pdecl = sym; 110 } 111 if (decl == NULL && sym->s_def == DECL) 112 decl = sym; 113 } 114 115 /* A prototype is better than an old-style declaration. */ 116 if (pdecl != NULL) 117 decl = pdecl; 118 119 chkvtui(hte, def, decl); 120 121 chkvtdi(hte, def, decl); 122 123 chkfaui(hte, def, decl); 124 125 check_return_values(hte, def); 126 127 check_argument_declarations(hte, def, decl); 128 } 129 130 /* 131 * Print a warning if the name has been used, but not defined. 132 */ 133 static void 134 check_used_not_defined(const hte_t *hte) 135 { 136 fcall_t *fcall; 137 usym_t *usym; 138 139 if (!hte->h_used || hte->h_def) 140 return; 141 142 if ((fcall = hte->h_calls) != NULL) { 143 /* %s is used in %s but never defined */ 144 msg(0, hte->h_name, mkpos(&fcall->f_pos)); 145 } else if ((usym = hte->h_usyms) != NULL) { 146 /* %s is used in %s but never defined */ 147 msg(0, hte->h_name, mkpos(&usym->u_pos)); 148 } 149 } 150 151 /* 152 * Print a warning if the name has been defined, but never used. 153 */ 154 static void 155 check_defined_not_used(const hte_t *hte) 156 { 157 sym_t *sym; 158 159 if (!hte->h_def || hte->h_used) 160 return; 161 162 for (sym = hte->h_syms; sym != NULL; sym = sym->s_next) { 163 if (sym->s_def == DEF || sym->s_def == TDEF) { 164 /* %s is defined in %s but never used */ 165 msg(1, hte->h_name, mkpos(&sym->s_pos)); 166 break; 167 } 168 } 169 } 170 171 /* 172 * Print a warning if the variable has been declared, but is not used 173 * or defined. 174 */ 175 static void 176 check_declared_not_used_or_defined(const hte_t *hte) 177 { 178 sym_t *sym; 179 180 if (hte->h_syms == NULL || hte->h_used || hte->h_def) 181 return; 182 183 sym = hte->h_syms; 184 if (TP(sym->s_type)->t_tspec == FUNC) 185 return; 186 187 if (sym->s_def != DECL) 188 errx(1, "internal error: check_declared_not_used_or_defined"); 189 /* %s is declared in %s but never used or defined */ 190 msg(2, hte->h_name, mkpos(&sym->s_pos)); 191 } 192 193 /* 194 * Print a warning if there is more than one definition for 195 * this name. 196 */ 197 static void 198 check_multiple_definitions(const hte_t *hte) 199 { 200 sym_t *sym, *def1; 201 202 if (!hte->h_def) 203 return; 204 205 def1 = NULL; 206 for (sym = hte->h_syms; sym != NULL; sym = sym->s_next) { 207 /* 208 * C90 allows tentative definitions of the same name in only 209 * one compilation unit. 210 */ 211 if (sym->s_def != DEF && (!sflag || sym->s_def != TDEF)) 212 continue; 213 if (sym->s_inline) 214 continue; 215 if (def1 == NULL) { 216 def1 = sym; 217 continue; 218 } 219 /* %s has multiple definitions in %s and %s */ 220 msg(3, hte->h_name, mkpos(&def1->s_pos), mkpos(&sym->s_pos)); 221 } 222 } 223 224 /* 225 * Print a warning if the return value assumed for a function call 226 * differs from the return value of the function definition or 227 * function declaration. 228 * 229 * If no definition/declaration can be found, the assumed return values 230 * are always int. So there is no need to compare with another function 231 * call as it's done for function arguments. 232 */ 233 static void 234 chkvtui(const hte_t *hte, sym_t *def, sym_t *decl) 235 { 236 fcall_t *call; 237 type_t *tp1, *tp2; 238 bool dowarn, eq; 239 tspec_t t1; 240 241 if (hte->h_calls == NULL) 242 return; 243 244 if (def == NULL) 245 def = decl; 246 if (def == NULL) 247 return; 248 249 t1 = (tp1 = TP(def->s_type)->t_subt)->t_tspec; 250 for (call = hte->h_calls; call != NULL; call = call->f_next) { 251 tp2 = TP(call->f_type)->t_subt; 252 eq = types_compatible(tp1, tp2, 253 true, false, false, (dowarn = false, &dowarn)); 254 if (!call->f_rused) { 255 /* no return value used */ 256 if ((t1 == STRUCT || t1 == UNION) && !eq) { 257 /* 258 * If a function returns a struct or union, it 259 * must be declared to return a struct or 260 * union, even if the return value is ignored. 261 * This is necessary because the caller must 262 * allocate stack space for the return value. 263 * If it does not, the return value would 264 * overwrite other data. 265 * 266 * XXX: The following message may be confusing 267 * because it occurs also if the return value 268 * was declared inconsistently. But this 269 * behavior matches pcc-based lint, so it is 270 * accepted for now. 271 */ 272 /* %s's return type in %s must be decl... */ 273 msg(17, hte->h_name, 274 mkpos(&def->s_pos), mkpos(&call->f_pos)); 275 } 276 continue; 277 } 278 if (!eq || (sflag && dowarn)) { 279 /* %s has its return value used inconsistently ... */ 280 msg(4, hte->h_name, 281 mkpos(&def->s_pos), mkpos(&call->f_pos)); 282 } 283 } 284 } 285 286 /* 287 * Print a warning if a definition/declaration does not match another 288 * definition/declaration of the same name. For functions, only the 289 * types of return values are tested. 290 */ 291 static void 292 chkvtdi(const hte_t *hte, sym_t *def, sym_t *decl) 293 { 294 sym_t *sym; 295 type_t *tp1, *tp2; 296 bool eq, dowarn; 297 298 if (def == NULL) 299 def = decl; 300 if (def == NULL) 301 return; 302 303 tp1 = TP(def->s_type); 304 for (sym = hte->h_syms; sym != NULL; sym = sym->s_next) { 305 type_t *xt1, *xt2; 306 if (sym == def) 307 continue; 308 tp2 = TP(sym->s_type); 309 dowarn = false; 310 if (tp1->t_tspec == FUNC && tp2->t_tspec == FUNC) { 311 eq = types_compatible(xt1 = tp1->t_subt, 312 xt2 = tp2->t_subt, true, false, false, &dowarn); 313 } else { 314 eq = types_compatible(xt1 = tp1, xt2 = tp2, 315 false, false, false, &dowarn); 316 } 317 if (!eq || (sflag && dowarn)) { 318 /* %s returns '%s' at %s, versus '%s' at %s */ 319 msg(5, hte->h_name, type_name(xt1), mkpos(&def->s_pos), 320 type_name(xt2), mkpos(&sym->s_pos)); 321 } 322 } 323 } 324 325 static int 326 total_args(int n, type_t **tpp) 327 { 328 for (; *tpp != NULL; tpp++) 329 n++; 330 return n; 331 } 332 333 /* 334 * Print a warning if a function is called with arguments which does 335 * not match the function definition, declaration or another call 336 * of the same function. 337 */ 338 static void 339 chkfaui(const hte_t *hte, sym_t *def, sym_t *decl) 340 { 341 type_t *tp1, *tp2, **ap1, **ap2; 342 pos_t *pos1p = NULL; 343 fcall_t *calls, *call, *call1; 344 int n, as; 345 arginf_t *ai; 346 347 if ((calls = hte->h_calls) == NULL) 348 return; 349 350 /* 351 * If we find a function definition, we use this for comparison, 352 * otherwise the first prototype we can find. If there is no definition 353 * or prototype declaration, the first function call is used. 354 */ 355 tp1 = NULL; 356 call1 = NULL; 357 if (def != NULL) { 358 if ((tp1 = TP(def->s_type))->t_tspec != FUNC) 359 return; 360 pos1p = &def->s_pos; 361 } else if (decl != NULL && TP(decl->s_type)->t_proto) { 362 if ((tp1 = TP(decl->s_type))->t_tspec != FUNC) 363 return; 364 pos1p = &decl->s_pos; 365 } 366 if (tp1 == NULL) { 367 call1 = calls; 368 calls = calls->f_next; 369 if ((tp1 = TP(call1->f_type))->t_tspec != FUNC) 370 return; 371 pos1p = &call1->f_pos; 372 } 373 374 n = 1; 375 for (call = calls; call != NULL; call = call->f_next) { 376 if ((tp2 = TP(call->f_type))->t_tspec != FUNC) 377 continue; 378 ap1 = tp1->t_args; 379 ap2 = tp2->t_args; 380 n = 0; 381 while (*ap1 != NULL && *ap2 != NULL) { 382 if (def != NULL && def->s_check_only_first_args && 383 n >= def->s_check_num_args) 384 break; 385 n++; 386 chkau(hte, n, def, decl, pos1p, call1, call, 387 *ap1, *ap2); 388 ap1++; 389 ap2++; 390 } 391 if (*ap1 == *ap2) { 392 /* equal # of arguments */ 393 } else if (def != NULL && def->s_check_only_first_args && 394 n >= def->s_check_num_args) { 395 /* 396 * function definition with VARARGS; The # of arguments 397 * of the call must be at least as large as the 398 * parameter of VARARGS. 399 */ 400 } else if (*ap2 != NULL && tp1->t_proto && tp1->t_vararg) { 401 /* 402 * prototype with ... and function call with at least 403 * the same # of arguments as declared in the 404 * prototype. 405 */ 406 } else { 407 /* %s has %d parameters in %s, versus %d ... */ 408 msg(7, hte->h_name, total_args(n, ap1), mkpos(pos1p), 409 total_args(n, ap2), mkpos(&call->f_pos)); 410 continue; 411 } 412 413 /* perform SCANFLIKE/PRINTFLIKE tests */ 414 if (def == NULL || (!def->s_printflike && !def->s_scanflike)) 415 continue; 416 as = def->s_printflike 417 ? def->s_printflike_arg 418 : def->s_scanflike_arg; 419 for (ai = call->f_args; ai != NULL; ai = ai->a_next) { 420 if (ai->a_num == as) 421 break; 422 } 423 if (ai == NULL || !ai->a_fmt) 424 continue; 425 if (def->s_printflike) { 426 printflike(hte, call, n, ai->a_fstrg, ap2); 427 } else { 428 scanflike(hte, call, n, ai->a_fstrg, ap2); 429 } 430 } 431 } 432 433 /* 434 * Check a single argument in a function call. 435 * 436 * hte a pointer to the hash table entry of the function 437 * n the number of the argument (1..) 438 * def the function definition or NULL 439 * decl prototype declaration, old-style declaration or NULL 440 * pos1p position of definition, declaration of first call 441 * call1 first call, if both def and decl are old-style def/decl 442 * call checked call 443 * arg1 currently checked argument of def/decl/call1 444 * arg2 currently checked argument of call 445 * 446 */ 447 static void 448 chkau(const hte_t *hte, int n, sym_t *def, sym_t *decl, pos_t *pos1p, 449 fcall_t *call1, fcall_t *call, type_t *arg1, type_t *arg2) 450 { 451 bool promote, asgn, dowarn; 452 tspec_t t1, t2; 453 arginf_t *ai, *ai1; 454 455 /* 456 * If a function definition is available (def != NULL), we compare the 457 * function call (call) with the definition. Otherwise, if a function 458 * definition is available and it is not an old-style definition (decl 459 * != NULL && TP(decl->s_type)->t_proto), we compare the call with this 460 * declaration. Otherwise we compare it with the first call we have 461 * found (call1). 462 */ 463 464 /* arg1 must be promoted if it stems from an old-style definition */ 465 promote = def != NULL && def->s_old_style_function; 466 467 /* 468 * If we compare with a definition or declaration, we must perform the 469 * same checks for qualifiers in indirected types as in assignments. 470 */ 471 asgn = def != NULL || (decl != NULL && TP(decl->s_type)->t_proto); 472 473 dowarn = false; 474 if (types_compatible(arg1, arg2, true, promote, asgn, &dowarn) && 475 (!sflag || !dowarn)) 476 return; 477 478 /*- 479 * Other lint implementations print warnings as soon as the type of an 480 * argument does not match exactly the expected type. The result are 481 * lots of warnings which are really not necessary. 482 * We print a warning only if 483 * (0) at least one type is not an integer type and types differ 484 * (1) hflag is set and types differ 485 * (2) types differ, except in signedness 486 * 487 * If the argument is an integer constant whose msb is not set, 488 * signedness is ignored (e.g. 0 matches both signed and unsigned int). 489 * This is with and without hflag. 490 * 491 * If the argument is an integer constant with value 0 and the expected 492 * argument is of type pointer and the width of the integer constant is 493 * the same as the width of the pointer, no warning is printed. 494 */ 495 t1 = arg1->t_tspec; 496 t2 = arg2->t_tspec; 497 if (is_integer(t1) && is_integer(t2) && 498 !arg1->t_is_enum && !arg2->t_is_enum) { 499 if (promote) { 500 /* 501 * XXX Here is a problem: Although it is possible to 502 * pass an int where a char/short it expected, there 503 * may be loss in significant digits. We should first 504 * check for const arguments if they can be converted 505 * into the original parameter type. 506 */ 507 if (t1 == FLOAT) { 508 t1 = DOUBLE; 509 } else if (t1 == CHAR || t1 == SCHAR) { 510 t1 = INT; 511 } else if (t1 == UCHAR) { 512 t1 = tflag ? UINT : INT; 513 } else if (t1 == SHORT) { 514 t1 = INT; 515 } else if (t1 == USHORT) { 516 /* CONSTCOND */ 517 t1 = INT_MAX < USHRT_MAX || tflag ? UINT : INT; 518 } 519 } 520 521 if (signed_type(t1) == signed_type(t2)) { 522 523 /* 524 * types differ only in signedness; get information 525 * about arguments 526 */ 527 528 /* 529 * treat a definition like a call with variable 530 * arguments 531 */ 532 ai1 = call1 != NULL ? call1->f_args : NULL; 533 534 /* 535 * if two calls are compared, ai1 is set to the 536 * information for the n-th argument, if this was a 537 * constant, otherwise to NULL 538 */ 539 for ( ; ai1 != NULL; ai1 = ai1->a_next) { 540 if (ai1->a_num == n) 541 break; 542 } 543 /* 544 * ai is set to the information of the n-th arg of the 545 * (second) call, if this was a constant, otherwise to 546 * NULL 547 */ 548 for (ai = call->f_args; ai != NULL; ai = ai->a_next) { 549 if (ai->a_num == n) 550 break; 551 } 552 553 if (ai1 == NULL && ai == NULL) { 554 /* no constant at all */ 555 if (!hflag) 556 return; 557 } else if (ai1 == NULL || ai == NULL) { 558 /* one constant */ 559 if (ai == NULL) 560 ai = ai1; 561 if (ai->a_zero || ai->a_pcon) 562 /* same value in signed and unsigned */ 563 return; 564 /* value (not representation) differently */ 565 } else { 566 /* 567 * two constants, one signed, one unsigned; if 568 * the msb of one of the constants is set, the 569 * argument is used inconsistently. 570 */ 571 if (!ai1->a_ncon && !ai->a_ncon) 572 return; 573 } 574 } 575 576 } else if (t1 == PTR && is_integer(t2)) { 577 for (ai = call->f_args; ai != NULL; ai = ai->a_next) { 578 if (ai->a_num == n) 579 break; 580 } 581 /* 582 * Vendor implementations of lint (e.g. HP-UX, Digital UNIX) 583 * don't care about the size of the integer argument, only 584 * whether or not it is zero. We do the same. 585 */ 586 if (ai != NULL && ai->a_zero) 587 return; 588 } 589 590 /* %s has argument %d with type '%s' at %s, versus '%s' at %s */ 591 msg(6, hte->h_name, n, type_name(arg1), mkpos(pos1p), 592 type_name(arg2), mkpos(&call->f_pos)); 593 } 594 595 /* 596 * Compare the types in the NULL-terminated array ap with the format 597 * string fmt. 598 */ 599 static void 600 printflike(const hte_t *hte, fcall_t *call, int n, const char *fmt, type_t **ap) 601 { 602 const char *fp; 603 char fc; 604 bool fwidth, prec, left, sign, space, alt, zero; 605 tspec_t sz, t1, t2 = NO_TSPEC; 606 type_t *tp; 607 608 fp = fmt; 609 fc = *fp++; 610 611 for (;;) { 612 if (fc == '\0') { 613 if (*ap != NULL) 614 too_many_arguments(hte, call); 615 break; 616 } 617 if (fc != '%') { 618 bad_format_string(hte, call); 619 break; 620 } 621 fc = *fp++; 622 fwidth = prec = left = sign = space = alt = zero = false; 623 sz = NO_TSPEC; 624 625 /* Flags */ 626 for (;;) { 627 if (fc == '-') { 628 if (left) 629 break; 630 left = true; 631 } else if (fc == '+') { 632 if (sign) 633 break; 634 sign = true; 635 } else if (fc == ' ') { 636 if (space) 637 break; 638 space = true; 639 } else if (fc == '#') { 640 if (alt) 641 break; 642 alt = true; 643 } else if (fc == '0') { 644 if (zero) 645 break; 646 zero = true; 647 } else { 648 break; 649 } 650 fc = *fp++; 651 } 652 653 /* field width */ 654 if (ch_isdigit(fc)) { 655 fwidth = true; 656 do { fc = *fp++; } while (ch_isdigit(fc)); 657 } else if (fc == '*') { 658 fwidth = true; 659 fc = *fp++; 660 if ((tp = *ap++) == NULL) { 661 too_few_arguments(hte, call); 662 break; 663 } 664 n++; 665 if ((t1 = tp->t_tspec) != INT && (hflag || t1 != UINT)) 666 inconsistent_arguments(hte, call, n); 667 } 668 669 /* precision */ 670 if (fc == '.') { 671 fc = *fp++; 672 prec = true; 673 if (ch_isdigit(fc)) { 674 do { 675 fc = *fp++; 676 } while (ch_isdigit(fc)); 677 } else if (fc == '*') { 678 fc = *fp++; 679 if ((tp = *ap++) == NULL) { 680 too_few_arguments(hte, call); 681 break; 682 } 683 n++; 684 if (tp->t_tspec != INT) 685 inconsistent_arguments(hte, call, n); 686 } else { 687 bad_format_string(hte, call); 688 break; 689 } 690 } 691 692 if (fc == 'h') { 693 sz = SHORT; 694 } else if (fc == 'l') { 695 sz = LONG; 696 } else if (fc == 'q') { 697 sz = LLONG; 698 } else if (fc == 'L') { 699 sz = LDOUBLE; 700 } 701 if (sz != NO_TSPEC) 702 fc = *fp++; 703 704 if (fc == '%') { 705 if (sz != NO_TSPEC || left || sign || space || 706 alt || zero || prec || fwidth) { 707 bad_format_string(hte, call); 708 } 709 fc = *fp++; 710 continue; 711 } 712 713 if (fc == '\0') { 714 bad_format_string(hte, call); 715 break; 716 } 717 718 if ((tp = *ap++) == NULL) { 719 too_few_arguments(hte, call); 720 break; 721 } 722 n++; 723 if ((t1 = tp->t_tspec) == PTR) 724 t2 = tp->t_subt->t_tspec; 725 726 if (fc == 'd' || fc == 'i') { 727 if (alt || sz == LDOUBLE) { 728 bad_format_string(hte, call); 729 break; 730 } 731 int_conv: 732 if (sz == LONG) { 733 if (t1 != LONG && (hflag || t1 != ULONG)) 734 inconsistent_arguments(hte, call, n); 735 } else if (sz == LLONG) { 736 if (t1 != LLONG && (hflag || t1 != ULLONG)) 737 inconsistent_arguments(hte, call, n); 738 } else { 739 /* 740 * SHORT is always promoted to INT, USHORT to 741 * INT or UINT. 742 */ 743 if (t1 != INT && (hflag || t1 != UINT)) 744 inconsistent_arguments(hte, call, n); 745 } 746 } else if (fc == 'o' || fc == 'u' || fc == 'x' || fc == 'X') { 747 if ((alt && fc == 'u') || sz == LDOUBLE) 748 bad_format_string(hte, call); 749 uint_conv: 750 if (sz == LONG) { 751 if (t1 != ULONG && (hflag || t1 != LONG)) 752 inconsistent_arguments(hte, call, n); 753 } else if (sz == LLONG) { 754 if (t1 != ULLONG && (hflag || t1 != LLONG)) 755 inconsistent_arguments(hte, call, n); 756 } else if (sz == SHORT) { 757 /* USHORT was promoted to INT or UINT */ 758 if (t1 != UINT && t1 != INT) 759 inconsistent_arguments(hte, call, n); 760 } else { 761 if (t1 != UINT && (hflag || t1 != INT)) 762 inconsistent_arguments(hte, call, n); 763 } 764 } else if (fc == 'D' || fc == 'O' || fc == 'U') { 765 if ((alt && fc != 'O') || sz != NO_TSPEC || !tflag) 766 bad_format_string(hte, call); 767 sz = LONG; 768 if (fc == 'D') { 769 goto int_conv; 770 } else { 771 goto uint_conv; 772 } 773 } else if (fc == 'f' || fc == 'e' || fc == 'E' || 774 fc == 'g' || fc == 'G') { 775 if (sz == NO_TSPEC) 776 sz = DOUBLE; 777 if (sz != DOUBLE && sz != LDOUBLE) 778 bad_format_string(hte, call); 779 if (t1 != sz) 780 inconsistent_arguments(hte, call, n); 781 } else if (fc == 'c') { 782 if (sz != NO_TSPEC || alt || zero) 783 bad_format_string(hte, call); 784 if (t1 != INT) 785 inconsistent_arguments(hte, call, n); 786 } else if (fc == 's') { 787 if (sz != NO_TSPEC || alt || zero) 788 bad_format_string(hte, call); 789 if (t1 != PTR || 790 (t2 != CHAR && t2 != UCHAR && t2 != SCHAR)) { 791 inconsistent_arguments(hte, call, n); 792 } 793 } else if (fc == 'p') { 794 if (fwidth || prec || sz != NO_TSPEC || alt || zero) 795 bad_format_string(hte, call); 796 if (t1 != PTR || (hflag && t2 != VOID)) 797 inconsistent_arguments(hte, call, n); 798 } else if (fc == 'n') { 799 if (fwidth || prec || alt || zero || sz == LDOUBLE) 800 bad_format_string(hte, call); 801 if (t1 != PTR) { 802 inconsistent_arguments(hte, call, n); 803 } else if (sz == LONG) { 804 if (t2 != LONG && t2 != ULONG) 805 inconsistent_arguments(hte, call, n); 806 } else if (sz == SHORT) { 807 if (t2 != SHORT && t2 != USHORT) 808 inconsistent_arguments(hte, call, n); 809 } else { 810 if (t2 != INT && t2 != UINT) 811 inconsistent_arguments(hte, call, n); 812 } 813 } else { 814 bad_format_string(hte, call); 815 break; 816 } 817 818 fc = *fp++; 819 } 820 } 821 822 /* 823 * Compare the types in the NULL-terminated array ap with the format 824 * string fmt. 825 */ 826 static void 827 scanflike(const hte_t *hte, fcall_t *call, int n, const char *fmt, type_t **ap) 828 { 829 const char *fp; 830 char fc; 831 bool noasgn, fwidth; 832 tspec_t sz, t1 = NO_TSPEC, t2 = NO_TSPEC; 833 type_t *tp = NULL; 834 835 fp = fmt; 836 fc = *fp++; 837 838 for (;;) { 839 if (fc == '\0') { 840 if (*ap != NULL) 841 too_many_arguments(hte, call); 842 break; 843 } 844 if (fc != '%') { 845 bad_format_string(hte, call); 846 break; 847 } 848 fc = *fp++; 849 850 noasgn = fwidth = false; 851 sz = NO_TSPEC; 852 853 if (fc == '*') { 854 noasgn = true; 855 fc = *fp++; 856 } 857 858 if (ch_isdigit(fc)) { 859 fwidth = true; 860 do { fc = *fp++; } while (ch_isdigit(fc)); 861 } 862 863 if (fc == 'h') { 864 sz = SHORT; 865 } else if (fc == 'l') { 866 sz = LONG; 867 } else if (fc == 'q') { 868 sz = LLONG; 869 } else if (fc == 'L') { 870 sz = LDOUBLE; 871 } 872 if (sz != NO_TSPEC) 873 fc = *fp++; 874 875 if (fc == '%') { 876 if (sz != NO_TSPEC || noasgn || fwidth) 877 bad_format_string(hte, call); 878 fc = *fp++; 879 continue; 880 } 881 882 if (!noasgn) { 883 if ((tp = *ap++) == NULL) { 884 too_few_arguments(hte, call); 885 break; 886 } 887 n++; 888 if ((t1 = tp->t_tspec) == PTR) 889 t2 = tp->t_subt->t_tspec; 890 } 891 892 if (fc == 'd' || fc == 'i' || fc == 'n') { 893 if (sz == LDOUBLE) 894 bad_format_string(hte, call); 895 if (sz != SHORT && sz != LONG && sz != LLONG) 896 sz = INT; 897 conv: 898 if (!noasgn) { 899 if (t1 != PTR) { 900 inconsistent_arguments(hte, call, n); 901 } else if (t2 != signed_type(sz)) { 902 inconsistent_arguments(hte, call, n); 903 } else if (hflag && t2 != sz) { 904 inconsistent_arguments(hte, call, n); 905 } else if (tp->t_subt->t_const) { 906 inconsistent_arguments(hte, call, n); 907 } 908 } 909 } else if (fc == 'o' || fc == 'u' || fc == 'x') { 910 if (sz == LDOUBLE) 911 bad_format_string(hte, call); 912 if (sz == SHORT) { 913 sz = USHORT; 914 } else if (sz == LONG) { 915 sz = ULONG; 916 } else if (sz == LLONG) { 917 sz = ULLONG; 918 } else { 919 sz = UINT; 920 } 921 goto conv; 922 } else if (fc == 'D') { 923 if (sz != NO_TSPEC || !tflag) 924 bad_format_string(hte, call); 925 sz = LONG; 926 goto conv; 927 } else if (fc == 'O') { 928 if (sz != NO_TSPEC || !tflag) 929 bad_format_string(hte, call); 930 sz = ULONG; 931 goto conv; 932 } else if (fc == 'X') { 933 /* 934 * XXX valid in C90, but in NetBSD's libc implemented 935 * as "lx". That's why it should be avoided. 936 */ 937 if (sz != NO_TSPEC || !tflag) 938 bad_format_string(hte, call); 939 sz = ULONG; 940 goto conv; 941 } else if (fc == 'E') { 942 /* 943 * XXX valid in C90, but in NetBSD's libc implemented 944 * as "lf". That's why it should be avoided. 945 */ 946 if (sz != NO_TSPEC || !tflag) 947 bad_format_string(hte, call); 948 sz = DOUBLE; 949 goto conv; 950 } else if (fc == 'F') { 951 /* XXX only for backward compatibility */ 952 if (sz != NO_TSPEC || !tflag) 953 bad_format_string(hte, call); 954 sz = DOUBLE; 955 goto conv; 956 } else if (fc == 'G') { 957 /* 958 * XXX valid in C90, but in NetBSD's libc not 959 * implemented 960 */ 961 if (sz != NO_TSPEC && sz != LONG && sz != LDOUBLE) 962 bad_format_string(hte, call); 963 goto fconv; 964 } else if (fc == 'e' || fc == 'f' || fc == 'g') { 965 fconv: 966 if (sz == NO_TSPEC) { 967 sz = FLOAT; 968 } else if (sz == LONG) { 969 sz = DOUBLE; 970 } else if (sz != LDOUBLE) { 971 bad_format_string(hte, call); 972 sz = FLOAT; 973 } 974 goto conv; 975 } else if (fc == 's' || fc == '[' || fc == 'c') { 976 if (sz != NO_TSPEC) 977 bad_format_string(hte, call); 978 if (fc == '[') { 979 if ((fc = *fp++) == '-') { 980 bad_format_string(hte, call); 981 fc = *fp++; 982 } 983 if (fc != ']') { 984 bad_format_string(hte, call); 985 if (fc == '\0') 986 break; 987 } 988 } 989 if (!noasgn) { 990 if (t1 != PTR) { 991 inconsistent_arguments(hte, call, n); 992 } else if (t2 != CHAR && t2 != UCHAR && 993 t2 != SCHAR) { 994 inconsistent_arguments(hte, call, n); 995 } 996 } 997 } else if (fc == 'p') { 998 if (sz != NO_TSPEC) 999 bad_format_string(hte, call); 1000 if (!noasgn) { 1001 if (t1 != PTR || t2 != PTR) { 1002 inconsistent_arguments(hte, call, n); 1003 } else if (tp->t_subt->t_subt->t_tspec!=VOID) { 1004 if (hflag) 1005 inconsistent_arguments(hte, call, n); 1006 } 1007 } 1008 } else { 1009 bad_format_string(hte, call); 1010 break; 1011 } 1012 1013 fc = *fp++; 1014 } 1015 } 1016 1017 static void 1018 bad_format_string(const hte_t *hte, fcall_t *call) 1019 { 1020 1021 /* %s is called with a malformed format string in %s */ 1022 msg(13, hte->h_name, mkpos(&call->f_pos)); 1023 } 1024 1025 static void 1026 inconsistent_arguments(const hte_t *hte, fcall_t *call, int n) 1027 { 1028 1029 /* %s is called in %s with argument %d being incompatible with ... */ 1030 msg(14, hte->h_name, mkpos(&call->f_pos), n); 1031 } 1032 1033 static void 1034 too_few_arguments(const hte_t *hte, fcall_t *call) 1035 { 1036 1037 /* %s is called in %s with too few arguments for format string */ 1038 msg(15, hte->h_name, mkpos(&call->f_pos)); 1039 } 1040 1041 static void 1042 too_many_arguments(const hte_t *hte, fcall_t *call) 1043 { 1044 1045 /* %s is called in %s with too many arguments for format string */ 1046 msg(16, hte->h_name, mkpos(&call->f_pos)); 1047 } 1048 1049 /* 1050 * List of functions where we usually don't care about their result. 1051 * NB: Must be sorted. 1052 */ 1053 static const char ignorelist[][8] = { 1054 "memcpy", 1055 "memmove", 1056 "memset", 1057 "printf", 1058 "strcat", 1059 "strcpy", 1060 "vprintf", 1061 }; 1062 1063 /* 1064 * Print warnings for return values which are used but not returned, 1065 * or return values which are always or sometimes ignored. 1066 */ 1067 static void 1068 check_return_values(const hte_t *hte, sym_t *def) 1069 { 1070 fcall_t *call; 1071 bool used, ignored; 1072 1073 if (def == NULL) 1074 /* don't know whether or not the functions returns a value */ 1075 return; 1076 1077 if (hte->h_calls == NULL) 1078 return; 1079 1080 if (def->s_function_has_return_value) { 1081 /* 1082 * XXX as soon as we are able to disable single warnings, the 1083 * following dependencies from hflag should be removed. But for 1084 * now I don't want to be bothered by these warnings which are 1085 * almost always useless. 1086 */ 1087 if (!hflag) 1088 return; 1089 if (hflag && bsearch(hte->h_name, ignorelist, 1090 sizeof(ignorelist) / sizeof(ignorelist[0]), 1091 sizeof(ignorelist[0]), 1092 (int (*)(const void *, const void *))strcmp) != NULL) 1093 return; 1094 1095 /* function has return value */ 1096 used = ignored = false; 1097 for (call = hte->h_calls; call != NULL; call = call->f_next) { 1098 used |= call->f_rused || call->f_rdisc; 1099 ignored |= !call->f_rused && !call->f_rdisc; 1100 } 1101 if (!used && ignored) { 1102 /* %s returns a value that is always ignored */ 1103 msg(8, hte->h_name); 1104 } else if (used && ignored) { 1105 /* %s returns a value that is sometimes ignored */ 1106 msg(9, hte->h_name); 1107 } 1108 } else { 1109 /* function has no return value */ 1110 for (call = hte->h_calls; call != NULL; call = call->f_next) { 1111 if (call->f_rused) 1112 /* %s has its return value used in %s but doesn't return one */ 1113 msg(10, hte->h_name, mkpos(&call->f_pos)); 1114 } 1115 } 1116 } 1117 1118 /* 1119 * Print warnings for inconsistent argument declarations. 1120 */ 1121 static void 1122 check_argument_declarations(const hte_t *hte, sym_t *def, sym_t *decl) 1123 { 1124 bool osdef, eq, dowarn; 1125 int n; 1126 sym_t *sym1, *sym; 1127 type_t **ap1, **ap2, *tp1, *tp2; 1128 1129 osdef = false; 1130 if (def != NULL) { 1131 osdef = def->s_old_style_function; 1132 sym1 = def; 1133 } else if (decl != NULL && TP(decl->s_type)->t_proto) { 1134 sym1 = decl; 1135 } else { 1136 return; 1137 } 1138 if (TP(sym1->s_type)->t_tspec != FUNC) 1139 return; 1140 1141 /* 1142 * XXX Prototypes should also be compared with old-style function 1143 * declarations. 1144 */ 1145 1146 for (sym = hte->h_syms; sym != NULL; sym = sym->s_next) { 1147 if (sym == sym1 || !TP(sym->s_type)->t_proto) 1148 continue; 1149 ap1 = TP(sym1->s_type)->t_args; 1150 ap2 = TP(sym->s_type)->t_args; 1151 n = 0; 1152 while (*ap1 != NULL && *ap2 != NULL) { 1153 type_t *xt1, *xt2; 1154 dowarn = false; 1155 eq = types_compatible(xt1 = *ap1, xt2 = *ap2, 1156 true, osdef, false, &dowarn); 1157 if (!eq || dowarn) { 1158 /* %s has parameter %d declared as '%s' ... */ 1159 msg(11, hte->h_name, n + 1, 1160 type_name(xt1), mkpos(&sym1->s_pos), 1161 type_name(xt2), mkpos(&sym->s_pos)); 1162 } 1163 n++; 1164 ap1++; 1165 ap2++; 1166 } 1167 if (*ap1 == *ap2) { 1168 tp1 = TP(sym1->s_type); 1169 tp2 = TP(sym->s_type); 1170 if (tp1->t_vararg == tp2->t_vararg) 1171 continue; 1172 if (tp2->t_vararg && sym1->s_check_only_first_args && 1173 sym1->s_check_num_args == n && !sflag) { 1174 continue; 1175 } 1176 } 1177 /* %s has %d parameters in %s, versus %d in %s */ 1178 msg(12, hte->h_name, 1179 total_args(n, ap1), mkpos(&sym1->s_pos), 1180 total_args(n, ap2), mkpos(&sym->s_pos)); 1181 } 1182 } 1183 1184 1185 /* 1186 * Check compatibility of two types. Returns whether types are compatible. 1187 * 1188 * ignqual if set, ignore qualifiers of outermost type; used for 1189 * function arguments 1190 * promote if set, promote left type before comparison; used for 1191 * comparisons of arguments with parameters of old-style 1192 * definitions 1193 * asgn left indirected type must have at least the same qualifiers 1194 * like right indirected type (for assignments and function 1195 * arguments) 1196 * *dowarn set to true if an old-style declaration was compared with 1197 * an incompatible prototype declaration 1198 */ 1199 static bool 1200 types_compatible(type_t *tp1, type_t *tp2, 1201 bool ignqual, bool promot, bool asgn, bool *dowarn) 1202 { 1203 tspec_t t, to; 1204 int indir; 1205 1206 to = NO_TSPEC; 1207 indir = 0; 1208 1209 while (tp1 != NULL && tp2 != NULL) { 1210 1211 t = tp1->t_tspec; 1212 if (promot) { 1213 if (t == FLOAT) { 1214 t = DOUBLE; 1215 } else if (t == CHAR || t == SCHAR) { 1216 t = INT; 1217 } else if (t == UCHAR) { 1218 t = tflag ? UINT : INT; 1219 } else if (t == SHORT) { 1220 t = INT; 1221 } else if (t == USHORT) { 1222 /* CONSTCOND */ 1223 t = INT_MAX < USHRT_MAX || tflag ? UINT : INT; 1224 } 1225 } 1226 1227 if (asgn && to == PTR) { 1228 if (indir == 1 && (t == VOID || tp2->t_tspec == VOID)) 1229 return true; 1230 } 1231 1232 if (t != tp2->t_tspec) { 1233 /* 1234 * Give pointer to types which differ only in 1235 * signedness a chance if not sflag and not hflag. 1236 */ 1237 if (sflag || hflag || to != PTR) 1238 return false; 1239 if (signed_type(t) != signed_type(tp2->t_tspec)) 1240 return false; 1241 } 1242 1243 if (tp1->t_is_enum && tp2->t_is_enum) { 1244 if (tp1->t_istag && tp2->t_istag) { 1245 return tp1->t_tag == tp2->t_tag; 1246 } else if (tp1->t_istynam && tp2->t_istynam) { 1247 return tp1->t_tynam == tp2->t_tynam; 1248 } else if (tp1->t_isuniqpos && tp2->t_isuniqpos) { 1249 return (tp1->t_uniqpos.p_line == 1250 tp2->t_uniqpos.p_line && 1251 tp1->t_uniqpos.p_file == 1252 tp2->t_uniqpos.p_file && 1253 tp1->t_uniqpos.p_uniq == 1254 tp2->t_uniqpos.p_uniq); 1255 } else { 1256 return false; 1257 } 1258 } 1259 1260 /* 1261 * XXX Handle combinations of enum and int if eflag is set. But 1262 * note: enum and 0 should be allowed. 1263 */ 1264 1265 if (asgn && indir == 1) { 1266 if (!tp1->t_const && tp2->t_const) 1267 return false; 1268 if (!tp1->t_volatile && tp2->t_volatile) 1269 return false; 1270 } else if (!ignqual && !tflag) { 1271 if (tp1->t_const != tp2->t_const) 1272 return false; 1273 if (tp1->t_const != tp2->t_const) 1274 return false; 1275 } 1276 1277 if (t == STRUCT || t == UNION) { 1278 if (tp1->t_istag && tp2->t_istag) { 1279 return tp1->t_tag == tp2->t_tag; 1280 } else if (tp1->t_istynam && tp2->t_istynam) { 1281 return tp1->t_tynam == tp2->t_tynam; 1282 } else if (tp1->t_isuniqpos && tp2->t_isuniqpos) { 1283 return (tp1->t_uniqpos.p_line == 1284 tp2->t_uniqpos.p_line && 1285 tp1->t_uniqpos.p_file == 1286 tp2->t_uniqpos.p_file && 1287 tp1->t_uniqpos.p_uniq == 1288 tp2->t_uniqpos.p_uniq); 1289 } else { 1290 return false; 1291 } 1292 } 1293 1294 if (t == ARRAY && tp1->t_dim != tp2->t_dim) { 1295 if (tp1->t_dim != 0 && tp2->t_dim != 0) 1296 return false; 1297 } 1298 1299 if (t == FUNC) { 1300 if (tp1->t_proto && tp2->t_proto) { 1301 if (!prototypes_compatible(tp1, tp2, dowarn)) 1302 return false; 1303 } else if (tp1->t_proto) { 1304 if (!matches_no_arg_function(tp1, dowarn)) 1305 return false; 1306 } else if (tp2->t_proto) { 1307 if (!matches_no_arg_function(tp2, dowarn)) 1308 return false; 1309 } 1310 } 1311 1312 tp1 = tp1->t_subt; 1313 tp2 = tp2->t_subt; 1314 ignqual = promot = false; 1315 to = t; 1316 indir++; 1317 } 1318 1319 return tp1 == tp2; 1320 } 1321 1322 /* 1323 * Compares arguments of two prototypes 1324 */ 1325 static bool 1326 prototypes_compatible(type_t *tp1, type_t *tp2, bool *dowarn) 1327 { 1328 type_t **a1, **a2; 1329 1330 if (tp1->t_vararg != tp2->t_vararg) 1331 return false; 1332 1333 a1 = tp1->t_args; 1334 a2 = tp2->t_args; 1335 1336 while (*a1 != NULL && *a2 != NULL) { 1337 1338 if (!types_compatible(*a1, *a2, true, false, false, dowarn)) 1339 return false; 1340 1341 a1++; 1342 a2++; 1343 } 1344 1345 return *a1 == *a2; 1346 } 1347 1348 /* 1349 * Returns whether all parameters of a prototype are compatible with an 1350 * old-style function declaration. 1351 * 1352 * This is the case if the following conditions are met: 1353 * 1. the prototype must have a fixed number of parameters 1354 * 2. no parameter is of type float 1355 * 3. no parameter is converted to another type if integer promotion 1356 * is applied on it 1357 */ 1358 static bool 1359 matches_no_arg_function(type_t *tp, bool *dowarn) 1360 { 1361 type_t **arg; 1362 tspec_t t; 1363 1364 if (tp->t_vararg && dowarn != NULL) 1365 *dowarn = true; 1366 for (arg = tp->t_args; *arg != NULL; arg++) { 1367 if ((t = (*arg)->t_tspec) == FLOAT) 1368 return false; 1369 if (t == CHAR || t == SCHAR || t == UCHAR) 1370 return false; 1371 if (t == SHORT || t == USHORT) 1372 return false; 1373 } 1374 return true; 1375 } 1376