1 /* vi: set sw=4 ts=4: */
3 * Mini diff implementation for busybox, adapted from OpenBSD diff.
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>
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.
13 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
17 * The following code uses an algorithm due to Harold Stone,
18 * which finds a pair of longest identical subsequences in
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
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.
38 * Next the indices that point into member are unsorted into
39 * array class according to the original order of file0.
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.
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
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.
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.
80 //config: bool "diff (13 kb)"
83 //config: diff compares two files or directories and outputs the
84 //config: differences between them in a form that can be given to
85 //config: the patch command.
87 //config:config FEATURE_DIFF_LONG_OPTIONS
88 //config: bool "Enable long options"
90 //config: depends on DIFF && LONG_OPTS
92 //config:config FEATURE_DIFF_DIR
93 //config: bool "Enable directory support"
95 //config: depends on DIFF
97 //config: This option enables support for directory and subdirectory
100 //kbuild:lib-$(CONFIG_DIFF) += diff.o
102 //applet:IF_DIFF(APPLET(diff, BB_DIR_USR_BIN, BB_SUID_DROP))
104 //usage:#define diff_trivial_usage
105 //usage: "[-abBdiNqrTstw] [-L LABEL] [-S FILE] [-U LINES] FILE1 FILE2"
106 //usage:#define diff_full_usage "\n\n"
107 //usage: "Compare files line by line and output the differences between them.\n"
108 //usage: "This implementation supports unified diffs only.\n"
109 //usage: "\n -a Treat all files as text"
110 //usage: "\n -b Ignore changes in the amount of whitespace"
111 //usage: "\n -B Ignore changes whose lines are all blank"
112 //usage: "\n -d Try hard to find a smaller set of changes"
113 //usage: "\n -i Ignore case differences"
114 //usage: "\n -L Use LABEL instead of the filename in the unified header"
115 //usage: "\n -N Treat absent files as empty"
116 //usage: "\n -q Output only whether files differ"
117 //usage: "\n -r Recurse"
118 //usage: "\n -S Start with FILE when comparing directories"
119 //usage: "\n -T Make tabs line up by prefixing a tab when necessary"
120 //usage: "\n -s Report when two files are the same"
121 //usage: "\n -t Expand tabs to spaces in output"
122 //usage: "\n -U Output LINES lines of context"
123 //usage: "\n -w Ignore all whitespace"
126 #include "common_bufsiz.h"
129 # define dbg_error_msg(...) bb_error_msg(__VA_ARGS__)
131 # define dbg_error_msg(...) ((void)0)
134 enum { /* print_status() and diffreg() return values */
135 STATUS_SAME, /* files are the same */
136 STATUS_DIFFER, /* files differ */
137 STATUS_BINARY, /* binary files differ */
140 enum { /* Commandline flags */
145 FLAG_L, /* never used, handled by getopt32 */
150 FLAG_S, /* never used, handled by getopt32 */
153 FLAG_U, /* never used, handled by getopt32 */
155 FLAG_u, /* ignored, this is the default */
156 FLAG_p, /* not implemented */
158 FLAG_E, /* not implemented */
160 #define FLAG(x) (1 << FLAG_##x)
162 /* We cache file position to avoid excessive seeking */
163 typedef struct FILE_and_pos_t {
169 smallint exit_status;
171 const char *other_dir;
175 #define G (*ptr_to_globals)
176 #define exit_status (G.exit_status )
177 #define opt_U_context (G.opt_U_context )
178 #define label (G.label )
180 #define INIT_G() do { \
181 SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
189 TOK_EMPTY = 1 << 9, /* Line fully processed, you can proceed to the next */
190 TOK_EOF = 1 << 10, /* File ended */
191 /* Private (Only to be used by read_token() */
192 TOK_EOL = 1 << 11, /* we saw EOL (sticky) */
193 TOK_SPACE = 1 << 12, /* used -b code, means we are skipping spaces */
194 SHIFT_EOF = (sizeof(token_t)*8 - 8) - 1,
195 CHAR_MASK = 0x1ff, /* 8th bit is used to distinguish EOF from 0xff */
198 /* Restores full EOF from one 8th bit: */
199 //#define TOK2CHAR(t) (((t) << SHIFT_EOF) >> SHIFT_EOF)
200 /* We don't really need the above, we only need to have EOF != any_real_char: */
201 #define TOK2CHAR(t) ((t) & CHAR_MASK)
203 static void seek_ft(FILE_and_pos_t *ft, off_t pos)
205 if (ft->ft_pos != pos) {
207 fseeko(ft->ft_fp, pos, SEEK_SET);
211 /* Reads tokens from given fp, handling -b and -w flags
212 * The user must reset tok every line start
214 static int read_token(FILE_and_pos_t *ft, token_t tok)
217 while (!(tok & TOK_EOL)) {
221 t = fgetc(ft->ft_fp);
224 is_space = (t == EOF || isspace(t));
226 /* If t == EOF (-1), set both TOK_EOF and TOK_EOL */
227 tok |= (t & (TOK_EOF + TOK_EOL));
232 if (option_mask32 & FLAG(i)) /* Handcoded tolower() */
233 t = (t >= 'A' && t <= 'Z') ? t - ('A' - 'a') : t;
235 if ((option_mask32 & FLAG(w)) && is_space)
238 /* Trim char value to low 9 bits */
241 if (option_mask32 & FLAG(b)) {
242 /* Was prev char whitespace? */
243 if (tok & TOK_SPACE) { /* yes */
244 if (is_space) /* this one too, ignore it */
247 } else if (is_space) {
248 /* 1st whitespace char.
249 * Set TOK_SPACE and replace char by ' ' */
254 tok &= ~(TOK_EMPTY + CHAR_MASK);
255 /* Assign char value (low 9 bits) and maybe set TOK_SPACE */
260 bb_error_msg("fp:%p tok:%x '%c'%s%s%s%s", fp, tok, tok & 0xff
261 , tok & TOK_EOF ? " EOF" : ""
262 , tok & TOK_EOL ? " EOL" : ""
263 , tok & TOK_EMPTY ? " EMPTY" : ""
264 , tok & TOK_SPACE ? " SPACE" : ""
276 static int search(const int *c, int k, int y, const struct cand *list)
280 if (list[c[k]].y < y) /* quick look for typical case */
283 for (i = 0, j = k + 1;;) {
284 const int l = (i + j) >> 1;
286 const int t = list[c[l]].y;
298 static void stone(const int *a, int n, const int *b, int *J, int pref)
300 const unsigned isq = isqrt(n);
301 const unsigned bound =
302 (option_mask32 & FLAG(d)) ? UINT_MAX : MAX(256, isq);
306 struct cand *clist = xzalloc(clistlen * sizeof(clist[0]));
309 int *klist = xzalloc((n + 2) * sizeof(klist[0]));
310 /*clist[0] = (struct cand){0}; - xzalloc did it */
313 for (cand.x = 1; cand.x <= n; cand.x++) {
314 int j = a[cand.x], oldl = 0;
315 unsigned numtries = 0;
319 cand.pred = klist[0];
322 if (cand.y <= clist[cand.pred].y)
324 l = search(klist, k, cand.y, clist);
326 cand.pred = klist[l - 1];
327 if (l <= k && clist[klist[l]].y <= cand.y)
329 if (clen == clistlen) {
330 clistlen = clistlen * 11 / 10;
331 clist = xrealloc(clist, clistlen * sizeof(clist[0]));
344 } while ((cand.y = b[++j]) > 0 && numtries < bound);
347 for (q = clist + klist[k]; q->y; q = clist + q->pred)
348 J[q->x + pref] = q->y + pref;
354 /* 'serial' is not used in the beginning, so we reuse it
355 * to store line offsets, thus reducing memory pressure
364 static void equiv(struct line *a, int n, struct line *b, int m, int *c)
368 while (i <= n && j <= m) {
369 if (a[i].value < b[j].value)
371 else if (a[i].value == b[j].value)
382 while (b[j + 1].value == b[j].value) {
390 static void unsort(const struct line *f, int l, int *b)
393 int *a = xmalloc((l + 1) * sizeof(a[0]));
394 for (i = 1; i <= l; i++)
395 a[f[i].serial] = f[i].value;
396 for (i = 1; i <= l; i++)
401 static int line_compar(const void *a, const void *b)
403 #define l0 ((const struct line*)a)
404 #define l1 ((const struct line*)b)
405 int r = l0->value - l1->value;
408 return l0->serial - l1->serial;
413 static void fetch(FILE_and_pos_t *ft, const off_t *ix, int a, int b, int ch)
416 for (i = a; i <= b; i++) {
417 seek_ft(ft, ix[i - 1]);
419 if (option_mask32 & FLAG(T))
421 for (j = 0, col = 0; j < ix[i] - ix[i - 1]; j++) {
422 int c = fgetc(ft->ft_fp);
424 puts("\n\\ No newline at end of file");
428 if (c == '\t' && (option_mask32 & FLAG(t)))
429 do putchar(' '); while (++col & 7);
438 /* Creates the match vector J, where J[i] is the index
439 * of the line in the new file corresponding to the line i
440 * in the old file. Lines start at 1 instead of 0, that value
441 * being used instead to denote no corresponding line.
442 * This vector is dynamically allocated and must be freed by the caller.
444 * * fp is an input parameter, where fp[0] and fp[1] are the open
445 * old file and new file respectively.
446 * * nlen is an output variable, where nlen[0] and nlen[1]
447 * gets the number of lines in the old and new file respectively.
448 * * ix is an output variable, where ix[0] and ix[1] gets
449 * assigned dynamically allocated vectors of the offsets of the lines
450 * of the old and new file respectively. These must be freed by the caller.
452 static NOINLINE int *create_J(FILE_and_pos_t ft[2], int nlen[2], off_t *ix[2])
454 int *J, slen[2], *class, *member;
455 struct line *nfile[2], *sfile[2];
456 int pref = 0, suff = 0, i, j, delta;
458 /* Lines of both files are hashed, and in the process
459 * their offsets are stored in the array ix[fileno]
460 * where fileno == 0 points to the old file, and
461 * fileno == 1 points to the new one.
463 for (i = 0; i < 2; i++) {
467 nfile[i] = xmalloc((sz + 3) * sizeof(nfile[i][0]));
468 /* ft gets here without the correct position, cant use seek_ft */
470 fseeko(ft[i].ft_fp, 0, SEEK_SET);
473 /* We could zalloc nfile, but then zalloc starts showing in gprof at ~1% */
474 nfile[i][0].offset = 0;
475 goto start; /* saves code */
477 tok = read_token(&ft[i], tok);
478 if (!(tok & TOK_EMPTY)) {
479 /* Hash algorithm taken from Robert Sedgewick, Algorithms in C, 3d ed., p 578. */
480 /*hash = hash * 128 - hash + TOK2CHAR(tok);
481 * gcc insists on optimizing above to "hash * 127 + ...", thus... */
482 unsigned o = hash - TOK2CHAR(tok);
483 hash = hash * 128 - o; /* we want SPEED here */
486 if (nlen[i]++ == sz) {
488 nfile[i] = xrealloc(nfile[i], (sz + 3) * sizeof(nfile[i][0]));
490 /* line_compar needs hashes fit into positive int */
491 nfile[i][nlen[i]].value = hash & INT_MAX;
492 /* like ftello(ft[i].ft_fp) but faster (avoids lseek syscall) */
493 nfile[i][nlen[i]].offset = ft[i].ft_pos;
495 /* EOF counts as a token, so we have to adjust it here */
496 nfile[i][nlen[i]].offset++;
502 /* Exclude lone EOF line from the end of the file, to make fetch()'s job easier */
503 if (nfile[i][nlen[i]].offset - nfile[i][nlen[i] - 1].offset == 1)
505 /* Now we copy the line offsets into ix */
506 ix[i] = xmalloc((nlen[i] + 2) * sizeof(ix[i][0]));
507 for (j = 0; j < nlen[i] + 1; j++)
508 ix[i][j] = nfile[i][j].offset;
511 /* length of prefix and suffix is calculated */
512 for (; pref < nlen[0] && pref < nlen[1] &&
513 nfile[0][pref + 1].value == nfile[1][pref + 1].value;
515 for (; suff < nlen[0] - pref && suff < nlen[1] - pref &&
516 nfile[0][nlen[0] - suff].value == nfile[1][nlen[1] - suff].value;
518 /* Arrays are pruned by the suffix and prefix length,
519 * the result being sorted and stored in sfile[fileno],
520 * and their sizes are stored in slen[fileno]
522 for (j = 0; j < 2; j++) {
523 sfile[j] = nfile[j] + pref;
524 slen[j] = nlen[j] - pref - suff;
525 for (i = 0; i <= slen[j]; i++)
526 sfile[j][i].serial = i;
527 qsort(sfile[j] + 1, slen[j], sizeof(*sfile[j]), line_compar);
529 /* nfile arrays are reused to reduce memory pressure
530 * The #if zeroed out section performs the same task as the
531 * one in the #else section.
532 * Peak memory usage is higher, but one array copy is avoided
533 * by not using unsort()
536 member = xmalloc((slen[1] + 2) * sizeof(member[0]));
537 equiv(sfile[0], slen[0], sfile[1], slen[1], member);
540 class = xmalloc((slen[0] + 1) * sizeof(class[0]));
541 for (i = 1; i <= slen[0]; i++) /* Unsorting */
542 class[sfile[0][i].serial] = sfile[0][i].value;
545 member = (int *)nfile[1];
546 equiv(sfile[0], slen[0], sfile[1], slen[1], member);
547 member = xrealloc(member, (slen[1] + 2) * sizeof(member[0]));
549 class = (int *)nfile[0];
550 unsort(sfile[0], slen[0], (int *)nfile[0]);
551 class = xrealloc(class, (slen[0] + 2) * sizeof(class[0]));
553 J = xmalloc((nlen[0] + 2) * sizeof(J[0]));
554 /* The elements of J which fall inside the prefix and suffix regions
555 * are marked as unchanged, while the ones which fall outside
556 * are initialized with 0 (no matches), so that function stone can
557 * then assign them their right values
559 for (i = 0, delta = nlen[1] - nlen[0]; i <= nlen[0]; i++)
560 J[i] = i <= pref ? i :
561 i > (nlen[0] - suff) ? (i + delta) : 0;
562 /* Here the magic is performed */
563 stone(class, slen[0], member, J, pref);
564 J[nlen[0] + 1] = nlen[1] + 1;
569 /* Both files are rescanned, in an effort to find any lines
570 * which, due to limitations intrinsic to any hashing algorithm,
571 * are different but ended up confounded as the same
573 for (i = 1; i <= nlen[0]; i++) {
577 seek_ft(&ft[0], ix[0][i - 1]);
578 seek_ft(&ft[1], ix[1][J[i] - 1]);
580 for (j = J[i]; i <= nlen[0] && J[i] == j; i++, j++) {
581 token_t tok0 = 0, tok1 = 0;
583 tok0 = read_token(&ft[0], tok0);
584 tok1 = read_token(&ft[1], tok1);
586 if (((tok0 ^ tok1) & TOK_EMPTY) != 0 /* one is empty (not both) */
587 || (!(tok0 & TOK_EMPTY) && TOK2CHAR(tok0) != TOK2CHAR(tok1))
589 J[i] = 0; /* Break the correspondence */
591 } while (!(tok0 & tok1 & TOK_EMPTY));
598 static bool diff(FILE* fp[2], char *file[2])
602 FILE_and_pos_t ft[2];
603 typedef struct { int a, b; } vec_t[2];
605 int i = 1, j, k, idx = -1;
606 bool anychange = false;
611 /* note that ft[i].ft_pos is unintitalized, create_J()
612 * must not assume otherwise */
613 J = create_J(ft, nlen, ix);
616 bool nonempty = false;
621 for (v[0].a = i; v[0].a <= nlen[0] && J[v[0].a] == J[v[0].a - 1] + 1; v[0].a++)
623 v[1].a = J[v[0].a - 1] + 1;
625 for (v[0].b = v[0].a - 1; v[0].b < nlen[0] && !J[v[0].b + 1]; v[0].b++)
627 v[1].b = J[v[0].b + 1] - 1;
629 * Indicate that there is a difference between lines a and b of the 'from' file
630 * to get to lines c to d of the 'to' file. If a is greater than b then there
631 * are no lines in the 'from' file involved and this means that there were
632 * lines appended (beginning at b). If c is greater than d then there are
633 * lines missing from the 'to' file.
635 if (v[0].a <= v[0].b || v[1].a <= v[1].b) {
637 * If this change is more than 'context' lines from the
638 * previous change, dump the record and reset it.
640 int ct = (2 * opt_U_context) + 1;
642 && v[0].a > vec[idx][0].b + ct
643 && v[1].a > vec[idx][1].b + ct
648 for (j = 0; j < 2; j++)
649 for (k = v[j].a; k <= v[j].b; k++)
650 nonempty |= (ix[j][k] - ix[j][k - 1] != 1);
652 vec = xrealloc_vector(vec, 6, ++idx);
653 memcpy(vec[idx], v, sizeof(v));
661 if (idx < 0 || ((option_mask32 & FLAG(B)) && !nonempty))
663 if (!(option_mask32 & FLAG(q))) {
665 vec_t span, *cvp = vec;
668 /* Print the context/unidiff header first time through */
669 printf("--- %s\n", label[0] ? label[0] : file[0]);
670 printf("+++ %s\n", label[1] ? label[1] : file[1]);
674 for (j = 0; j < 2; j++) {
675 int a = span[j].a = MAX(1, (*cvp)[j].a - opt_U_context);
676 int b = span[j].b = MIN(nlen[j], vec[idx][j].b + opt_U_context);
678 printf(" %c%d", j ? '+' : '-', MIN(a, b));
681 printf(",%d", (a < b) ? b - a + 1 : 0);
685 * Output changes in "unified" diff format--the old and new lines
686 * are printed together.
688 for (lowa = span[0].a; ; lowa = (*cvp++)[0].b + 1) {
689 bool end = cvp > &vec[idx];
690 fetch(&ft[0], ix[0], lowa, end ? span[0].b : (*cvp)[0].a - 1, ' ');
693 for (j = 0; j < 2; j++)
694 fetch(&ft[j], ix[j], (*cvp)[j].a, (*cvp)[j].b, j ? '+' : '-');
700 } while (i <= nlen[0]);
709 static int diffreg(char *file[2])
712 bool binary = false, differ = false;
713 int status = STATUS_SAME, i;
717 for (i = 0; i < 2; i++) {
718 int fd = STDIN_FILENO;
719 if (!LONE_DASH(file[i])) {
720 if (!(option_mask32 & FLAG(N))) {
721 fd = open_or_warn(file[i], O_RDONLY);
725 /* -N: if some file does not exist compare it like empty */
726 fd = open(file[i], O_RDONLY);
728 fd = xopen("/dev/null", O_RDONLY);
731 /* Our diff implementation is using seek.
732 * When we meet non-seekable file, we must make a temp copy.
734 if (lseek(fd, 0, SEEK_SET) == -1 && errno == ESPIPE) {
735 char name[] = "/tmp/difXXXXXX";
736 int fd_tmp = xmkstemp(name);
739 if (bb_copyfd_eof(fd, fd_tmp) < 0)
741 if (fd != STDIN_FILENO)
744 xlseek(fd, 0, SEEK_SET);
746 fp[i] = fdopen(fd, "r");
749 setup_common_bufsiz();
751 const size_t sz = COMMON_BUFSIZE / 2;
752 char *const buf0 = bb_common_bufsiz1;
753 char *const buf1 = buf0 + sz;
755 i = fread(buf0, 1, sz, fp[0]);
756 j = fread(buf1, 1, sz, fp[1]);
763 for (k = 0; k < i; k++) {
764 if (!buf0[k] || !buf1[k])
766 if (buf0[k] != buf1[k])
771 if (binary && !(option_mask32 & FLAG(a)))
772 status = STATUS_BINARY;
773 else if (diff(fp, file))
774 status = STATUS_DIFFER;
776 if (status != STATUS_SAME)
779 fclose_if_not_stdin(fp[0]);
780 fclose_if_not_stdin(fp[1]);
785 static void print_status(int status, char *path[2])
790 if ((option_mask32 & FLAG(q)) || status == STATUS_BINARY)
791 printf("Files %s and %s differ\n", path[0], path[1]);
794 if (option_mask32 & FLAG(s))
795 printf("Files %s and %s are identical\n", path[0], path[1]);
800 #if ENABLE_FEATURE_DIFF_DIR
807 /* This function adds a filename to dl, the directory listing. */
808 static int FAST_FUNC add_to_dirlist(const char *filename,
809 struct stat *sb UNUSED_PARAM,
810 void *userdata, int depth UNUSED_PARAM)
812 struct dlist *const l = userdata;
813 const char *file = filename + l->len;
816 l->dl = xrealloc_vector(l->dl, 6, l->e);
817 l->dl[l->e] = xstrdup(file);
822 /* If recursion is not set, this function adds the directory
823 * to the list and prevents recursive_action from recursing into it.
825 static int FAST_FUNC skip_dir(const char *filename,
826 struct stat *sb, void *userdata,
829 if (!(option_mask32 & FLAG(r)) && depth) {
830 add_to_dirlist(filename, sb, userdata, depth);
833 if (!(option_mask32 & FLAG(N))) {
834 /* -r without -N: no need to recurse into dirs
835 * which do not exist on the "other side".
836 * Testcase: diff -r /tmp /
837 * (it would recurse deep into /proc without this code) */
838 struct dlist *const l = userdata;
842 char *othername = concat_path_file(G.other_dir, filename);
843 int r = stat(othername, &osb);
845 if (r != 0 || !S_ISDIR(osb.st_mode)) {
846 /* other dir doesn't have similarly named
847 * directory, don't recurse; return 1 upon
848 * exit, just like diffutils' diff */
857 static void diffdir(char *p[2], const char *s_start)
859 struct dlist list[2];
862 memset(&list, 0, sizeof(list));
863 for (i = 0; i < 2; i++) {
864 /*list[i].s = list[i].e = 0; - memset did it */
865 /*list[i].dl = NULL; */
867 G.other_dir = p[1 - i];
868 /* We need to trim root directory prefix.
869 * Using list.len to specify its length,
870 * add_to_dirlist will remove it. */
871 list[i].len = strlen(p[i]);
872 recursive_action(p[i], ACTION_RECURSE | ACTION_FOLLOWLINKS,
873 add_to_dirlist, skip_dir, &list[i], 0);
874 /* Sort dl alphabetically.
875 * GNU diff does this ignoring any number of trailing dots.
876 * We don't, so for us dotted files almost always are
879 qsort_string_vector(list[i].dl, list[i].e);
880 /* If -S was set, find the starting point. */
883 while (list[i].s < list[i].e && strcmp(list[i].dl[list[i].s], s_start) < 0)
886 /* Now that both dirlist1 and dirlist2 contain sorted directory
887 * listings, we can start to go through dirlist1. If both listings
888 * contain the same file, then do a normal diff. Otherwise, behaviour
889 * is determined by whether the -N flag is set. */
895 dp[0] = list[0].s < list[0].e ? list[0].dl[list[0].s] : NULL;
896 dp[1] = list[1].s < list[1].e ? list[1].dl[list[1].s] : NULL;
897 if (!dp[0] && !dp[1])
899 pos = !dp[0] ? 1 : (!dp[1] ? -1 : strcmp(dp[0], dp[1]));
901 if (pos && !(option_mask32 & FLAG(N))) {
902 printf("Only in %s: %s\n", p[k], dp[k]);
905 char *fullpath[2], *path[2]; /* if -N */
907 for (i = 0; i < 2; i++) {
908 if (pos == 0 || i == k) {
909 path[i] = fullpath[i] = concat_path_file(p[i], dp[i]);
910 stat(fullpath[i], &stb[i]);
912 fullpath[i] = concat_path_file(p[i], dp[1 - i]);
913 path[i] = (char *)bb_dev_null;
917 stat(fullpath[k], &stb[1 - k]);
919 if (S_ISDIR(stb[0].st_mode) && S_ISDIR(stb[1].st_mode))
920 printf("Common subdirectories: %s and %s\n", fullpath[0], fullpath[1]);
921 else if (!S_ISREG(stb[0].st_mode) && !S_ISDIR(stb[0].st_mode))
922 printf("File %s is not a regular file or directory and was skipped\n", fullpath[0]);
923 else if (!S_ISREG(stb[1].st_mode) && !S_ISDIR(stb[1].st_mode))
924 printf("File %s is not a regular file or directory and was skipped\n", fullpath[1]);
925 else if (S_ISDIR(stb[0].st_mode) != S_ISDIR(stb[1].st_mode)) {
926 if (S_ISDIR(stb[0].st_mode))
927 printf("File %s is a %s while file %s is a %s\n", fullpath[0], "directory", fullpath[1], "regular file");
929 printf("File %s is a %s while file %s is a %s\n", fullpath[0], "regular file", fullpath[1], "directory");
931 print_status(diffreg(path), fullpath);
943 if (ENABLE_FEATURE_CLEAN_UP) {
950 #if ENABLE_FEATURE_DIFF_LONG_OPTIONS
951 static const char diff_longopts[] ALIGN1 =
952 "ignore-case\0" No_argument "i"
953 "ignore-tab-expansion\0" No_argument "E"
954 "ignore-space-change\0" No_argument "b"
955 "ignore-all-space\0" No_argument "w"
956 "ignore-blank-lines\0" No_argument "B"
957 "text\0" No_argument "a"
958 "unified\0" Required_argument "U"
959 "label\0" Required_argument "L"
960 "show-c-function\0" No_argument "p"
961 "brief\0" No_argument "q"
962 "expand-tabs\0" No_argument "t"
963 "initial-tab\0" No_argument "T"
964 "recursive\0" No_argument "r"
965 "new-file\0" No_argument "N"
966 "report-identical-files\0" No_argument "s"
967 "starting-file\0" Required_argument "S"
968 "minimal\0" No_argument "d"
970 # define GETOPT32 getopt32long
971 # define LONGOPTS ,diff_longopts
973 # define GETOPT32 getopt32
977 int diff_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
978 int diff_main(int argc UNUSED_PARAM, char **argv)
981 char *file[2], *s_start = NULL;
982 llist_t *L_arg = NULL;
986 /* exactly 2 params; collect multiple -L <label>; -U N */
987 GETOPT32(argv, "^" "abdiL:*NqrsS:tTU:+wupBE" "\0" "=2"
989 &L_arg, &s_start, &opt_U_context);
992 label[!!label[0]] = llist_pop(&L_arg);
994 /* Compat: "diff file name_which_doesnt_exist" exits with 2 */
995 xfunc_error_retval = 2;
996 for (i = 0; i < 2; i++) {
998 if (LONE_DASH(file[i])) {
999 fstat(STDIN_FILENO, &stb[i]);
1001 } else if (option_mask32 & FLAG(N)) {
1002 if (stat(file[i], &stb[i]))
1003 xstat("/dev/null", &stb[i]);
1005 xstat(file[i], &stb[i]);
1008 xfunc_error_retval = 1;
1010 if (gotstdin && (S_ISDIR(stb[0].st_mode) || S_ISDIR(stb[1].st_mode)))
1011 bb_error_msg_and_die("can't compare stdin to a directory");
1013 /* Compare metadata to check if the files are the same physical file.
1015 * Comment from diffutils source says:
1016 * POSIX says that two files are identical if st_ino and st_dev are
1017 * the same, but many file systems incorrectly assign the same (device,
1018 * inode) pair to two distinct files, including:
1019 * GNU/Linux NFS servers that export all local file systems as a
1020 * single NFS file system, if a local device number (st_dev) exceeds
1021 * 255, or if a local inode number (st_ino) exceeds 16777215.
1024 && stb[0].st_ino == stb[1].st_ino
1025 && stb[0].st_dev == stb[1].st_dev
1026 && stb[0].st_size == stb[1].st_size
1027 && stb[0].st_mtime == stb[1].st_mtime
1028 && stb[0].st_ctime == stb[1].st_ctime
1029 && stb[0].st_mode == stb[1].st_mode
1030 && stb[0].st_nlink == stb[1].st_nlink
1031 && stb[0].st_uid == stb[1].st_uid
1032 && stb[0].st_gid == stb[1].st_gid
1034 /* files are physically the same; no need to compare them */
1038 if (S_ISDIR(stb[0].st_mode) && S_ISDIR(stb[1].st_mode)) {
1039 #if ENABLE_FEATURE_DIFF_DIR
1040 diffdir(file, s_start);
1042 bb_error_msg_and_die("no support for directory comparison");
1045 bool dirfile = S_ISDIR(stb[0].st_mode) || S_ISDIR(stb[1].st_mode);
1046 bool dir = S_ISDIR(stb[1].st_mode);
1048 const char *slash = strrchr(file[!dir], '/');
1049 file[dir] = concat_path_file(file[dir], slash ? slash + 1 : file[!dir]);
1050 xstat(file[dir], &stb[dir]);
1052 /* diffreg can get non-regular files here */
1053 print_status(gotstdin > 1 ? STATUS_SAME : diffreg(file), file);