1/* vi: set sw=4 ts=4: */ 2/* 3 * Mini diff implementation for busybox, adapted from OpenBSD diff. 4 * 5 * Copyright (C) 2010 by Matheus Izvekov <mizvekov@gmail.com> 6 * Copyright (C) 2006 by Robert Sullivan <cogito.ergo.cogito@hotmail.com> 7 * Copyright (c) 2003 Todd C. Miller <Todd.Miller@courtesan.com> 8 * 9 * Sponsored in part by the Defense Advanced Research Projects 10 * Agency (DARPA) and Air Force Research Laboratory, Air Force 11 * Materiel Command, USAF, under agreement number F39502-99-1-0512. 12 * 13 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details. 14 */ 15 16/* 17 * The following code uses an algorithm due to Harold Stone, 18 * which finds a pair of longest identical subsequences in 19 * the two files. 20 * 21 * The major goal is to generate the match vector J. 22 * J[i] is the index of the line in file1 corresponding 23 * to line i in file0. J[i] = 0 if there is no 24 * such line in file1. 25 * 26 * Lines are hashed so as to work in core. All potential 27 * matches are located by sorting the lines of each file 28 * on the hash (called "value"). In particular, this 29 * collects the equivalence classes in file1 together. 30 * Subroutine equiv replaces the value of each line in 31 * file0 by the index of the first element of its 32 * matching equivalence in (the reordered) file1. 33 * To save space equiv squeezes file1 into a single 34 * array member in which the equivalence classes 35 * are simply concatenated, except that their first 36 * members are flagged by changing sign. 37 * 38 * Next the indices that point into member are unsorted into 39 * array class according to the original order of file0. 40 * 41 * The cleverness lies in routine stone. This marches 42 * through the lines of file0, developing a vector klist 43 * of "k-candidates". At step i a k-candidate is a matched 44 * pair of lines x,y (x in file0, y in file1) such that 45 * there is a common subsequence of length k 46 * between the first i lines of file0 and the first y 47 * lines of file1, but there is no such subsequence for 48 * any smaller y. x is the earliest possible mate to y 49 * that occurs in such a subsequence. 50 * 51 * Whenever any of the members of the equivalence class of 52 * lines in file1 matable to a line in file0 has serial number 53 * less than the y of some k-candidate, that k-candidate 54 * with the smallest such y is replaced. The new 55 * k-candidate is chained (via pred) to the current 56 * k-1 candidate so that the actual subsequence can 57 * be recovered. When a member has serial number greater 58 * that the y of all k-candidates, the klist is extended. 59 * At the end, the longest subsequence is pulled out 60 * and placed in the array J by unravel 61 * 62 * With J in hand, the matches there recorded are 63 * checked against reality to assure that no spurious 64 * matches have crept in due to hashing. If they have, 65 * they are broken, and "jackpot" is recorded--a harmless 66 * matter except that a true match for a spuriously 67 * mated line may now be unnecessarily reported as a change. 68 * 69 * Much of the complexity of the program comes simply 70 * from trying to minimize core utilization and 71 * maximize the range of doable problems by dynamically 72 * allocating what is needed and reusing what is not. 73 * The core requirements for problems larger than somewhat 74 * are (in words) 2*length(file0) + length(file1) + 75 * 3*(number of k-candidates installed), typically about 76 * 6n words for files of length n. 77 */ 78 79#include "libbb.h" 80 81#if 0 82//#define dbg_error_msg(...) bb_error_msg(__VA_ARGS__) 83#else 84#define dbg_error_msg(...) ((void)0) 85#endif 86 87enum { /* print_status() and diffreg() return values */ 88 STATUS_SAME, /* files are the same */ 89 STATUS_DIFFER, /* files differ */ 90 STATUS_BINARY, /* binary files differ */ 91}; 92 93enum { /* Commandline flags */ 94 FLAG_a, 95 FLAG_b, 96 FLAG_d, 97 FLAG_i, 98 FLAG_L, /* never used, handled by getopt32 */ 99 FLAG_N, 100 FLAG_q, 101 FLAG_r, 102 FLAG_s, 103 FLAG_S, /* never used, handled by getopt32 */ 104 FLAG_t, 105 FLAG_T, 106 FLAG_U, /* never used, handled by getopt32 */ 107 FLAG_w, 108 FLAG_u, /* ignored, this is the default */ 109 FLAG_p, /* not implemented */ 110 FLAG_B, 111 FLAG_E, /* not implemented */ 112}; 113#define FLAG(x) (1 << FLAG_##x) 114 115/* We cache file position to avoid excessive seeking */ 116typedef struct FILE_and_pos_t { 117 FILE *ft_fp; 118 off_t ft_pos; 119} FILE_and_pos_t; 120 121struct globals { 122 smallint exit_status; 123 int opt_U_context; 124 const char *other_dir; 125 char *label[2]; 126 struct stat stb[2]; 127}; 128#define G (*ptr_to_globals) 129#define exit_status (G.exit_status ) 130#define opt_U_context (G.opt_U_context ) 131#define label (G.label ) 132#define stb (G.stb ) 133#define INIT_G() do { \ 134 SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \ 135 opt_U_context = 3; \ 136} while (0) 137 138typedef int token_t; 139 140enum { 141 /* Public */ 142 TOK_EMPTY = 1 << 9, /* Line fully processed, you can proceed to the next */ 143 TOK_EOF = 1 << 10, /* File ended */ 144 /* Private (Only to be used by read_token() */ 145 TOK_EOL = 1 << 11, /* we saw EOL (sticky) */ 146 TOK_SPACE = 1 << 12, /* used -b code, means we are skipping spaces */ 147 SHIFT_EOF = (sizeof(token_t)*8 - 8) - 1, 148 CHAR_MASK = 0x1ff, /* 8th bit is used to distinguish EOF from 0xff */ 149}; 150 151/* Restores full EOF from one 8th bit: */ 152//#define TOK2CHAR(t) (((t) << SHIFT_EOF) >> SHIFT_EOF) 153/* We don't really need the above, we only need to have EOF != any_real_char: */ 154#define TOK2CHAR(t) ((t) & CHAR_MASK) 155 156static void seek_ft(FILE_and_pos_t *ft, off_t pos) 157{ 158 if (ft->ft_pos != pos) { 159 ft->ft_pos = pos; 160 fseeko(ft->ft_fp, pos, SEEK_SET); 161 } 162} 163 164/* Reads tokens from given fp, handling -b and -w flags 165 * The user must reset tok every line start 166 */ 167static int read_token(FILE_and_pos_t *ft, token_t tok) 168{ 169 tok |= TOK_EMPTY; 170 while (!(tok & TOK_EOL)) { 171 bool is_space; 172 int t; 173 174 t = fgetc(ft->ft_fp); 175 if (t != EOF) 176 ft->ft_pos++; 177 is_space = (t == EOF || isspace(t)); 178 179 /* If t == EOF (-1), set both TOK_EOF and TOK_EOL */ 180 tok |= (t & (TOK_EOF + TOK_EOL)); 181 /* Only EOL? */ 182 if (t == '\n') 183 tok |= TOK_EOL; 184 185 if (option_mask32 & FLAG(i)) /* Handcoded tolower() */ 186 t = (t >= 'A' && t <= 'Z') ? t - ('A' - 'a') : t; 187 188 if ((option_mask32 & FLAG(w)) && is_space) 189 continue; 190 191 /* Trim char value to low 9 bits */ 192 t &= CHAR_MASK; 193 194 if (option_mask32 & FLAG(b)) { 195 /* Was prev char whitespace? */ 196 if (tok & TOK_SPACE) { /* yes */ 197 if (is_space) /* this one too, ignore it */ 198 continue; 199 tok &= ~TOK_SPACE; 200 } else if (is_space) { 201 /* 1st whitespace char. 202 * Set TOK_SPACE and replace char by ' ' */ 203 t = TOK_SPACE + ' '; 204 } 205 } 206 /* Clear EMPTY */ 207 tok &= ~(TOK_EMPTY + CHAR_MASK); 208 /* Assign char value (low 9 bits) and maybe set TOK_SPACE */ 209 tok |= t; 210 break; 211 } 212#if 0 213 bb_error_msg("fp:%p tok:%x '%c'%s%s%s%s", fp, tok, tok & 0xff 214 , tok & TOK_EOF ? " EOF" : "" 215 , tok & TOK_EOL ? " EOL" : "" 216 , tok & TOK_EMPTY ? " EMPTY" : "" 217 , tok & TOK_SPACE ? " SPACE" : "" 218 ); 219#endif 220 return tok; 221} 222 223struct cand { 224 int x; 225 int y; 226 int pred; 227}; 228 229static int search(const int *c, int k, int y, const struct cand *list) 230{ 231 int i, j; 232 233 if (list[c[k]].y < y) /* quick look for typical case */ 234 return k + 1; 235 236 for (i = 0, j = k + 1;;) { 237 const int l = (i + j) >> 1; 238 if (l > i) { 239 const int t = list[c[l]].y; 240 if (t > y) 241 j = l; 242 else if (t < y) 243 i = l; 244 else 245 return l; 246 } else 247 return l + 1; 248 } 249} 250 251static unsigned isqrt(unsigned n) 252{ 253 unsigned x = 1; 254 while (1) { 255 const unsigned y = x; 256 x = ((n / x) + x) >> 1; 257 if (x <= (y + 1) && x >= (y - 1)) 258 return x; 259 } 260} 261 262static void stone(const int *a, int n, const int *b, int *J, int pref) 263{ 264 const unsigned isq = isqrt(n); 265 const unsigned bound = 266 (option_mask32 & FLAG(d)) ? UINT_MAX : MAX(256, isq); 267 int clen = 1; 268 int clistlen = 100; 269 int k = 0; 270 struct cand *clist = xzalloc(clistlen * sizeof(clist[0])); 271 struct cand cand; 272 struct cand *q; 273 int *klist = xzalloc((n + 2) * sizeof(klist[0])); 274 /*clist[0] = (struct cand){0}; - xzalloc did it */ 275 /*klist[0] = 0; */ 276 277 for (cand.x = 1; cand.x <= n; cand.x++) { 278 int j = a[cand.x], oldl = 0; 279 unsigned numtries = 0; 280 if (j == 0) 281 continue; 282 cand.y = -b[j]; 283 cand.pred = klist[0]; 284 do { 285 int l, tc; 286 if (cand.y <= clist[cand.pred].y) 287 continue; 288 l = search(klist, k, cand.y, clist); 289 if (l != oldl + 1) 290 cand.pred = klist[l - 1]; 291 if (l <= k && clist[klist[l]].y <= cand.y) 292 continue; 293 if (clen == clistlen) { 294 clistlen = clistlen * 11 / 10; 295 clist = xrealloc(clist, clistlen * sizeof(clist[0])); 296 } 297 clist[clen] = cand; 298 tc = klist[l]; 299 klist[l] = clen++; 300 if (l <= k) { 301 cand.pred = tc; 302 oldl = l; 303 numtries++; 304 } else { 305 k++; 306 break; 307 } 308 } while ((cand.y = b[++j]) > 0 && numtries < bound); 309 } 310 /* Unravel */ 311 for (q = clist + klist[k]; q->y; q = clist + q->pred) 312 J[q->x + pref] = q->y + pref; 313 free(klist); 314 free(clist); 315} 316 317struct line { 318 /* 'serial' is not used in the begining, so we reuse it 319 * to store line offsets, thus reducing memory pressure 320 */ 321 union { 322 unsigned serial; 323 off_t offset; 324 }; 325 unsigned value; 326}; 327 328static void equiv(struct line *a, int n, struct line *b, int m, int *c) 329{ 330 int i = 1, j = 1; 331 332 while (i <= n && j <= m) { 333 if (a[i].value < b[j].value) 334 a[i++].value = 0; 335 else if (a[i].value == b[j].value) 336 a[i++].value = j; 337 else 338 j++; 339 } 340 while (i <= n) 341 a[i++].value = 0; 342 b[m + 1].value = 0; 343 j = 0; 344 while (++j <= m) { 345 c[j] = -b[j].serial; 346 while (b[j + 1].value == b[j].value) { 347 j++; 348 c[j] = b[j].serial; 349 } 350 } 351 c[j] = -1; 352} 353 354static void unsort(const struct line *f, int l, int *b) 355{ 356 int i; 357 int *a = xmalloc((l + 1) * sizeof(a[0])); 358 for (i = 1; i <= l; i++) 359 a[f[i].serial] = f[i].value; 360 for (i = 1; i <= l; i++) 361 b[i] = a[i]; 362 free(a); 363} 364 365static int line_compar(const void *a, const void *b) 366{ 367#define l0 ((const struct line*)a) 368#define l1 ((const struct line*)b) 369 int r = l0->value - l1->value; 370 if (r) 371 return r; 372 return l0->serial - l1->serial; 373#undef l0 374#undef l1 375} 376 377static void fetch(FILE_and_pos_t *ft, const off_t *ix, int a, int b, int ch) 378{ 379 int i, j, col; 380 for (i = a; i <= b; i++) { 381 seek_ft(ft, ix[i - 1]); 382 putchar(ch); 383 if (option_mask32 & FLAG(T)) 384 putchar('\t'); 385 for (j = 0, col = 0; j < ix[i] - ix[i - 1]; j++) { 386 int c = fgetc(ft->ft_fp); 387 if (c == EOF) { 388 printf("\n\\ No newline at end of file\n"); 389 return; 390 } 391 ft->ft_pos++; 392 if (c == '\t' && (option_mask32 & FLAG(t))) 393 do putchar(' '); while (++col & 7); 394 else { 395 putchar(c); 396 col++; 397 } 398 } 399 } 400} 401 402/* Creates the match vector J, where J[i] is the index 403 * of the line in the new file corresponding to the line i 404 * in the old file. Lines start at 1 instead of 0, that value 405 * being used instead to denote no corresponding line. 406 * This vector is dynamically allocated and must be freed by the caller. 407 * 408 * * fp is an input parameter, where fp[0] and fp[1] are the open 409 * old file and new file respectively. 410 * * nlen is an output variable, where nlen[0] and nlen[1] 411 * gets the number of lines in the old and new file respectively. 412 * * ix is an output variable, where ix[0] and ix[1] gets 413 * assigned dynamically allocated vectors of the offsets of the lines 414 * of the old and new file respectively. These must be freed by the caller. 415 */ 416static NOINLINE int *create_J(FILE_and_pos_t ft[2], int nlen[2], off_t *ix[2]) 417{ 418 int *J, slen[2], *class, *member; 419 struct line *nfile[2], *sfile[2]; 420 int pref = 0, suff = 0, i, j, delta; 421 422 /* Lines of both files are hashed, and in the process 423 * their offsets are stored in the array ix[fileno] 424 * where fileno == 0 points to the old file, and 425 * fileno == 1 points to the new one. 426 */ 427 for (i = 0; i < 2; i++) { 428 unsigned hash; 429 token_t tok; 430 size_t sz = 100; 431 nfile[i] = xmalloc((sz + 3) * sizeof(nfile[i][0])); 432 /* ft gets here without the correct position, cant use seek_ft */ 433 ft[i].ft_pos = 0; 434 fseeko(ft[i].ft_fp, 0, SEEK_SET); 435 436 nlen[i] = 0; 437 /* We could zalloc nfile, but then zalloc starts showing in gprof at ~1% */ 438 nfile[i][0].offset = 0; 439 goto start; /* saves code */ 440 while (1) { 441 tok = read_token(&ft[i], tok); 442 if (!(tok & TOK_EMPTY)) { 443 /* Hash algorithm taken from Robert Sedgewick, Algorithms in C, 3d ed., p 578. */ 444 /*hash = hash * 128 - hash + TOK2CHAR(tok); 445 * gcc insists on optimizing above to "hash * 127 + ...", thus... */ 446 unsigned o = hash - TOK2CHAR(tok); 447 hash = hash * 128 - o; /* we want SPEED here */ 448 continue; 449 } 450 if (nlen[i]++ == sz) { 451 sz = sz * 3 / 2; 452 nfile[i] = xrealloc(nfile[i], (sz + 3) * sizeof(nfile[i][0])); 453 } 454 /* line_compar needs hashes fit into positive int */ 455 nfile[i][nlen[i]].value = hash & INT_MAX; 456 /* like ftello(ft[i].ft_fp) but faster (avoids lseek syscall) */ 457 nfile[i][nlen[i]].offset = ft[i].ft_pos; 458 if (tok & TOK_EOF) { 459 /* EOF counts as a token, so we have to adjust it here */ 460 nfile[i][nlen[i]].offset++; 461 break; 462 } 463start: 464 hash = tok = 0; 465 } 466 /* Exclude lone EOF line from the end of the file, to make fetch()'s job easier */ 467 if (nfile[i][nlen[i]].offset - nfile[i][nlen[i] - 1].offset == 1) 468 nlen[i]--; 469 /* Now we copy the line offsets into ix */ 470 ix[i] = xmalloc((nlen[i] + 2) * sizeof(ix[i][0])); 471 for (j = 0; j < nlen[i] + 1; j++) 472 ix[i][j] = nfile[i][j].offset; 473 } 474 475 /* length of prefix and suffix is calculated */ 476 for (; pref < nlen[0] && pref < nlen[1] && 477 nfile[0][pref + 1].value == nfile[1][pref + 1].value; 478 pref++); 479 for (; suff < nlen[0] - pref && suff < nlen[1] - pref && 480 nfile[0][nlen[0] - suff].value == nfile[1][nlen[1] - suff].value; 481 suff++); 482 /* Arrays are pruned by the suffix and prefix lenght, 483 * the result being sorted and stored in sfile[fileno], 484 * and their sizes are stored in slen[fileno] 485 */ 486 for (j = 0; j < 2; j++) { 487 sfile[j] = nfile[j] + pref; 488 slen[j] = nlen[j] - pref - suff; 489 for (i = 0; i <= slen[j]; i++) 490 sfile[j][i].serial = i; 491 qsort(sfile[j] + 1, slen[j], sizeof(*sfile[j]), line_compar); 492 } 493 /* nfile arrays are reused to reduce memory pressure 494 * The #if zeroed out section performs the same task as the 495 * one in the #else section. 496 * Peak memory usage is higher, but one array copy is avoided 497 * by not using unsort() 498 */ 499#if 0 500 member = xmalloc((slen[1] + 2) * sizeof(member[0])); 501 equiv(sfile[0], slen[0], sfile[1], slen[1], member); 502 free(nfile[1]); 503 504 class = xmalloc((slen[0] + 1) * sizeof(class[0])); 505 for (i = 1; i <= slen[0]; i++) /* Unsorting */ 506 class[sfile[0][i].serial] = sfile[0][i].value; 507 free(nfile[0]); 508#else 509 member = (int *)nfile[1]; 510 equiv(sfile[0], slen[0], sfile[1], slen[1], member); 511 member = xrealloc(member, (slen[1] + 2) * sizeof(member[0])); 512 513 class = (int *)nfile[0]; 514 unsort(sfile[0], slen[0], (int *)nfile[0]); 515 class = xrealloc(class, (slen[0] + 2) * sizeof(class[0])); 516#endif 517 J = xmalloc((nlen[0] + 2) * sizeof(J[0])); 518 /* The elements of J which fall inside the prefix and suffix regions 519 * are marked as unchanged, while the ones which fall outside 520 * are initialized with 0 (no matches), so that function stone can 521 * then assign them their right values 522 */ 523 for (i = 0, delta = nlen[1] - nlen[0]; i <= nlen[0]; i++) 524 J[i] = i <= pref ? i : 525 i > (nlen[0] - suff) ? (i + delta) : 0; 526 /* Here the magic is performed */ 527 stone(class, slen[0], member, J, pref); 528 J[nlen[0] + 1] = nlen[1] + 1; 529 530 free(class); 531 free(member); 532 533 /* Both files are rescanned, in an effort to find any lines 534 * which, due to limitations intrinsic to any hashing algorithm, 535 * are different but ended up confounded as the same 536 */ 537 for (i = 1; i <= nlen[0]; i++) { 538 if (!J[i]) 539 continue; 540 541 seek_ft(&ft[0], ix[0][i - 1]); 542 seek_ft(&ft[1], ix[1][J[i] - 1]); 543 544 for (j = J[i]; i <= nlen[0] && J[i] == j; i++, j++) { 545 token_t tok0 = 0, tok1 = 0; 546 do { 547 tok0 = read_token(&ft[0], tok0); 548 tok1 = read_token(&ft[1], tok1); 549 550 if (((tok0 ^ tok1) & TOK_EMPTY) != 0 /* one is empty (not both) */ 551 || (!(tok0 & TOK_EMPTY) && TOK2CHAR(tok0) != TOK2CHAR(tok1)) 552 ) { 553 J[i] = 0; /* Break the correspondence */ 554 } 555 } while (!(tok0 & tok1 & TOK_EMPTY)); 556 } 557 } 558 559 return J; 560} 561 562static bool diff(FILE* fp[2], char *file[2]) 563{ 564 int nlen[2]; 565 off_t *ix[2]; 566 FILE_and_pos_t ft[2]; 567 typedef struct { int a, b; } vec_t[2]; 568 vec_t *vec = NULL; 569 int i = 1, j, k, idx = -1; 570 bool anychange = false; 571 int *J; 572 573 ft[0].ft_fp = fp[0]; 574 ft[1].ft_fp = fp[1]; 575 /* note that ft[i].ft_pos is unintitalized, create_J() 576 * must not assume otherwise */ 577 J = create_J(ft, nlen, ix); 578 579 do { 580 bool nonempty = false; 581 582 while (1) { 583 vec_t v; 584 585 for (v[0].a = i; v[0].a <= nlen[0] && J[v[0].a] == J[v[0].a - 1] + 1; v[0].a++) 586 continue; 587 v[1].a = J[v[0].a - 1] + 1; 588 589 for (v[0].b = v[0].a - 1; v[0].b < nlen[0] && !J[v[0].b + 1]; v[0].b++) 590 continue; 591 v[1].b = J[v[0].b + 1] - 1; 592 /* 593 * Indicate that there is a difference between lines a and b of the 'from' file 594 * to get to lines c to d of the 'to' file. If a is greater than b then there 595 * are no lines in the 'from' file involved and this means that there were 596 * lines appended (beginning at b). If c is greater than d then there are 597 * lines missing from the 'to' file. 598 */ 599 if (v[0].a <= v[0].b || v[1].a <= v[1].b) { 600 /* 601 * If this change is more than 'context' lines from the 602 * previous change, dump the record and reset it. 603 */ 604 int ct = (2 * opt_U_context) + 1; 605 if (idx >= 0 606 && v[0].a > vec[idx][0].b + ct 607 && v[1].a > vec[idx][1].b + ct 608 ) { 609 break; 610 } 611 612 for (j = 0; j < 2; j++) 613 for (k = v[j].a; k < v[j].b; k++) 614 nonempty |= (ix[j][k+1] - ix[j][k] != 1); 615 616 vec = xrealloc_vector(vec, 6, ++idx); 617 memcpy(vec[idx], v, sizeof(v)); 618 } 619 620 i = v[0].b + 1; 621 if (i > nlen[0]) 622 break; 623 J[v[0].b] = v[1].b; 624 } 625 if (idx < 0 || ((option_mask32 & FLAG(B)) && !nonempty)) 626 goto cont; 627 if (!(option_mask32 & FLAG(q))) { 628 int lowa; 629 vec_t span, *cvp = vec; 630 631 if (!anychange) { 632 /* Print the context/unidiff header first time through */ 633 printf("--- %s\n", label[0] ? label[0] : file[0]); 634 printf("+++ %s\n", label[1] ? label[1] : file[1]); 635 } 636 637 printf("@@"); 638 for (j = 0; j < 2; j++) { 639 int a = span[j].a = MAX(1, (*cvp)[j].a - opt_U_context); 640 int b = span[j].b = MIN(nlen[j], vec[idx][j].b + opt_U_context); 641 642 printf(" %c%d", j ? '+' : '-', MIN(a, b)); 643 if (a == b) 644 continue; 645 printf(",%d", (a < b) ? b - a + 1 : 0); 646 } 647 printf(" @@\n"); 648 /* 649 * Output changes in "unified" diff format--the old and new lines 650 * are printed together. 651 */ 652 for (lowa = span[0].a; ; lowa = (*cvp++)[0].b + 1) { 653 bool end = cvp > &vec[idx]; 654 fetch(&ft[0], ix[0], lowa, end ? span[0].b : (*cvp)[0].a - 1, ' '); 655 if (end) 656 break; 657 for (j = 0; j < 2; j++) 658 fetch(&ft[j], ix[j], (*cvp)[j].a, (*cvp)[j].b, j ? '+' : '-'); 659 } 660 } 661 anychange = true; 662 cont: 663 idx = -1; 664 } while (i <= nlen[0]); 665 666 free(vec); 667 free(ix[0]); 668 free(ix[1]); 669 free(J); 670 return anychange; 671} 672 673static int diffreg(char *file[2]) 674{ 675 FILE *fp[2] = { stdin, stdin }; 676 bool binary = false, differ = false; 677 int status = STATUS_SAME, i; 678 679 for (i = 0; i < 2; i++) { 680 int fd = open_or_warn_stdin(file[i]); 681 if (fd == -1) 682 goto out; 683 /* Our diff implementation is using seek. 684 * When we meet non-seekable file, we must make a temp copy. 685 */ 686 if (lseek(fd, 0, SEEK_SET) == -1 && errno == ESPIPE) { 687 char name[] = "/tmp/difXXXXXX"; 688 int fd_tmp = mkstemp(name); 689 if (fd_tmp < 0) 690 bb_perror_msg_and_die("mkstemp"); 691 unlink(name); 692 if (bb_copyfd_eof(fd, fd_tmp) < 0) 693 xfunc_die(); 694 if (fd) /* Prevents closing of stdin */ 695 close(fd); 696 fd = fd_tmp; 697 } 698 fp[i] = fdopen(fd, "r"); 699 } 700 701 while (1) { 702 const size_t sz = COMMON_BUFSIZE / 2; 703 char *const buf0 = bb_common_bufsiz1; 704 char *const buf1 = buf0 + sz; 705 int j, k; 706 i = fread(buf0, 1, sz, fp[0]); 707 j = fread(buf1, 1, sz, fp[1]); 708 if (i != j) { 709 differ = true; 710 i = MIN(i, j); 711 } 712 if (i == 0) 713 break; 714 for (k = 0; k < i; k++) { 715 if (!buf0[k] || !buf1[k]) 716 binary = true; 717 if (buf0[k] != buf1[k]) 718 differ = true; 719 } 720 } 721 if (differ) { 722 if (binary && !(option_mask32 & FLAG(a))) 723 status = STATUS_BINARY; 724 else if (diff(fp, file)) 725 status = STATUS_DIFFER; 726 } 727 if (status != STATUS_SAME) 728 exit_status |= 1; 729out: 730 fclose_if_not_stdin(fp[0]); 731 fclose_if_not_stdin(fp[1]); 732 733 return status; 734} 735 736static void print_status(int status, char *path[2]) 737{ 738 switch (status) { 739 case STATUS_BINARY: 740 case STATUS_DIFFER: 741 if ((option_mask32 & FLAG(q)) || status == STATUS_BINARY) 742 printf("Files %s and %s differ\n", path[0], path[1]); 743 break; 744 case STATUS_SAME: 745 if (option_mask32 & FLAG(s)) 746 printf("Files %s and %s are identical\n", path[0], path[1]); 747 break; 748 } 749} 750 751#if ENABLE_FEATURE_DIFF_DIR 752struct dlist { 753 size_t len; 754 int s, e; 755 char **dl; 756}; 757 758/* This function adds a filename to dl, the directory listing. */ 759static int FAST_FUNC add_to_dirlist(const char *filename, 760 struct stat *sb UNUSED_PARAM, 761 void *userdata, int depth UNUSED_PARAM) 762{ 763 struct dlist *const l = userdata; 764 const char *file = filename + l->len; 765 while (*file == '/') 766 file++; 767 l->dl = xrealloc_vector(l->dl, 6, l->e); 768 l->dl[l->e] = xstrdup(file); 769 l->e++; 770 return TRUE; 771} 772 773/* If recursion is not set, this function adds the directory 774 * to the list and prevents recursive_action from recursing into it. 775 */ 776static int FAST_FUNC skip_dir(const char *filename, 777 struct stat *sb, void *userdata, 778 int depth) 779{ 780 if (!(option_mask32 & FLAG(r)) && depth) { 781 add_to_dirlist(filename, sb, userdata, depth); 782 return SKIP; 783 } 784 if (!(option_mask32 & FLAG(N))) { 785 /* -r without -N: no need to recurse into dirs 786 * which do not exist on the "other side". 787 * Testcase: diff -r /tmp / 788 * (it would recurse deep into /proc without this code) */ 789 struct dlist *const l = userdata; 790 filename += l->len; 791 if (filename[0]) { 792 struct stat osb; 793 char *othername = concat_path_file(G.other_dir, filename); 794 int r = stat(othername, &osb); 795 free(othername); 796 if (r != 0 || !S_ISDIR(osb.st_mode)) { 797 /* other dir doesn't have similarly named 798 * directory, don't recurse */ 799 return SKIP; 800 } 801 } 802 } 803 return TRUE; 804} 805 806static void diffdir(char *p[2], const char *s_start) 807{ 808 struct dlist list[2]; 809 int i; 810 811 memset(&list, 0, sizeof(list)); 812 for (i = 0; i < 2; i++) { 813 /*list[i].s = list[i].e = 0; - memset did it */ 814 /*list[i].dl = NULL; */ 815 816 G.other_dir = p[1 - i]; 817 /* We need to trim root directory prefix. 818 * Using list.len to specify its length, 819 * add_to_dirlist will remove it. */ 820 list[i].len = strlen(p[i]); 821 recursive_action(p[i], ACTION_RECURSE | ACTION_FOLLOWLINKS, 822 add_to_dirlist, skip_dir, &list[i], 0); 823 /* Sort dl alphabetically. 824 * GNU diff does this ignoring any number of trailing dots. 825 * We don't, so for us dotted files almost always are 826 * first on the list. 827 */ 828 qsort_string_vector(list[i].dl, list[i].e); 829 /* If -S was set, find the starting point. */ 830 if (!s_start) 831 continue; 832 while (list[i].s < list[i].e && strcmp(list[i].dl[list[i].s], s_start) < 0) 833 list[i].s++; 834 } 835 /* Now that both dirlist1 and dirlist2 contain sorted directory 836 * listings, we can start to go through dirlist1. If both listings 837 * contain the same file, then do a normal diff. Otherwise, behaviour 838 * is determined by whether the -N flag is set. */ 839 while (1) { 840 char *dp[2]; 841 int pos; 842 int k; 843 844 dp[0] = list[0].s < list[0].e ? list[0].dl[list[0].s] : NULL; 845 dp[1] = list[1].s < list[1].e ? list[1].dl[list[1].s] : NULL; 846 if (!dp[0] && !dp[1]) 847 break; 848 pos = !dp[0] ? 1 : (!dp[1] ? -1 : strcmp(dp[0], dp[1])); 849 k = pos > 0; 850 if (pos && !(option_mask32 & FLAG(N))) 851 printf("Only in %s: %s\n", p[k], dp[k]); 852 else { 853 char *fullpath[2], *path[2]; /* if -N */ 854 855 for (i = 0; i < 2; i++) { 856 if (pos == 0 || i == k) { 857 path[i] = fullpath[i] = concat_path_file(p[i], dp[i]); 858 stat(fullpath[i], &stb[i]); 859 } else { 860 fullpath[i] = concat_path_file(p[i], dp[1 - i]); 861 path[i] = (char *)bb_dev_null; 862 } 863 } 864 if (pos) 865 stat(fullpath[k], &stb[1 - k]); 866 867 if (S_ISDIR(stb[0].st_mode) && S_ISDIR(stb[1].st_mode)) 868 printf("Common subdirectories: %s and %s\n", fullpath[0], fullpath[1]); 869 else if (!S_ISREG(stb[0].st_mode) && !S_ISDIR(stb[0].st_mode)) 870 printf("File %s is not a regular file or directory and was skipped\n", fullpath[0]); 871 else if (!S_ISREG(stb[1].st_mode) && !S_ISDIR(stb[1].st_mode)) 872 printf("File %s is not a regular file or directory and was skipped\n", fullpath[1]); 873 else if (S_ISDIR(stb[0].st_mode) != S_ISDIR(stb[1].st_mode)) { 874 if (S_ISDIR(stb[0].st_mode)) 875 printf("File %s is a %s while file %s is a %s\n", fullpath[0], "directory", fullpath[1], "regular file"); 876 else 877 printf("File %s is a %s while file %s is a %s\n", fullpath[0], "regular file", fullpath[1], "directory"); 878 } else 879 print_status(diffreg(path), fullpath); 880 881 free(fullpath[0]); 882 free(fullpath[1]); 883 } 884 free(dp[k]); 885 list[k].s++; 886 if (pos == 0) { 887 free(dp[1 - k]); 888 list[1 - k].s++; 889 } 890 } 891 if (ENABLE_FEATURE_CLEAN_UP) { 892 free(list[0].dl); 893 free(list[1].dl); 894 } 895} 896#endif 897 898#if ENABLE_FEATURE_DIFF_LONG_OPTIONS 899static const char diff_longopts[] ALIGN1 = 900 "ignore-case\0" No_argument "i" 901 "ignore-tab-expansion\0" No_argument "E" 902 "ignore-space-change\0" No_argument "b" 903 "ignore-all-space\0" No_argument "w" 904 "ignore-blank-lines\0" No_argument "B" 905 "text\0" No_argument "a" 906 "unified\0" Required_argument "U" 907 "label\0" Required_argument "L" 908 "show-c-function\0" No_argument "p" 909 "brief\0" No_argument "q" 910 "expand-tabs\0" No_argument "t" 911 "initial-tab\0" No_argument "T" 912 "recursive\0" No_argument "r" 913 "new-file\0" No_argument "N" 914 "report-identical-files\0" No_argument "s" 915 "starting-file\0" Required_argument "S" 916 "minimal\0" No_argument "d" 917 ; 918#endif 919 920int diff_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; 921int diff_main(int argc UNUSED_PARAM, char **argv) 922{ 923 int gotstdin = 0, i; 924 char *file[2], *s_start = NULL; 925 llist_t *L_arg = NULL; 926 927 INIT_G(); 928 929 /* exactly 2 params; collect multiple -L <label>; -U N */ 930 opt_complementary = "=2:L::U+"; 931#if ENABLE_FEATURE_DIFF_LONG_OPTIONS 932 applet_long_options = diff_longopts; 933#endif 934 getopt32(argv, "abdiL:NqrsS:tTU:wupBE", 935 &L_arg, &s_start, &opt_U_context); 936 argv += optind; 937 while (L_arg) 938 label[!!label[0]] = llist_pop(&L_arg); 939 xfunc_error_retval = 2; 940 for (i = 0; i < 2; i++) { 941 file[i] = argv[i]; 942 /* Compat: "diff file name_which_doesnt_exist" exits with 2 */ 943 if (LONE_DASH(file[i])) { 944 fstat(STDIN_FILENO, &stb[i]); 945 gotstdin++; 946 } else 947 xstat(file[i], &stb[i]); 948 } 949 xfunc_error_retval = 1; 950 if (gotstdin && (S_ISDIR(stb[0].st_mode) || S_ISDIR(stb[1].st_mode))) 951 bb_error_msg_and_die("can't compare stdin to a directory"); 952 953 if (S_ISDIR(stb[0].st_mode) && S_ISDIR(stb[1].st_mode)) { 954#if ENABLE_FEATURE_DIFF_DIR 955 diffdir(file, s_start); 956#else 957 bb_error_msg_and_die("no support for directory comparison"); 958#endif 959 } else { 960 bool dirfile = S_ISDIR(stb[0].st_mode) || S_ISDIR(stb[1].st_mode); 961 bool dir = S_ISDIR(stb[1].st_mode); 962 if (dirfile) { 963 const char *slash = strrchr(file[!dir], '/'); 964 file[dir] = concat_path_file(file[dir], slash ? slash + 1 : file[!dir]); 965 xstat(file[dir], &stb[dir]); 966 } 967 /* diffreg can get non-regular files here */ 968 print_status(gotstdin > 1 ? STATUS_SAME : diffreg(file), file); 969 970 if (dirfile) 971 free(file[dir]); 972 } 973 974 return exit_status; 975} 976