1 /* $OpenBSD: diff3prog.c,v 1.11 2009/10/27 23:59:37 deraadt Exp $ */
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41 * modification, are permitted provided that the following conditions
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61 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
64 * @(#)diff3.c 8.1 (Berkeley) 6/6/93
69 static char sccsid[] = "@(#)diff3.c 8.1 (Berkeley) 6/6/93";
72 #include <sys/cdefs.h>
73 __FBSDID("$FreeBSD$");
75 #include <sys/capsicum.h>
76 #include <sys/procdesc.h>
77 #include <sys/types.h>
78 #include <sys/event.h>
81 #include <capsicum_helpers.h>
94 * "from" is first in range of changed lines; "to" is last+1
95 * from=to=line after point of insertion for added lines.
110 /* Ranges as lines */
115 static size_t szchanges;
117 static struct diff *d13;
118 static struct diff *d23;
120 * "de" is used to gather editing scripts. These are later spewed out in
121 * reverse order. Its first element must be all zero, the "old" and "new"
122 * components of "de" contain line positions. Array overlap indicates which
123 * sections in "de" correspond to lines that are different in all three files.
125 static struct diff *de;
126 static char *overlap;
127 static int overlapcnt;
129 static int cline[3]; /* # of the last-read line in each file (0-2) */
131 * The latest known correspondence between line numbers of the 3 files
132 * is stored in last[1-3];
135 static int Aflag, eflag, iflag, mflag, Tflag;
136 static int oflag; /* indicates whether to mark overlaps (-E or -X) */
138 static char *f1mark, *f2mark, *f3mark;
139 static const char *oldmark = "<<<<<<<";
140 static const char *orgmark = "|||||||";
141 static const char *newmark = ">>>>>>>";
143 static bool duplicate(struct range *, struct range *);
144 static int edit(struct diff *, bool, int, int);
145 static char *getchange(FILE *);
146 static char *get_line(FILE *, size_t *);
147 static int readin(int fd, struct diff **);
148 static int skip(int, int, const char *);
149 static void change(int, struct range *, bool);
150 static void keep(int, struct range *);
151 static void merge(int, int);
152 static void prange(struct range *, bool);
153 static void repos(int);
154 static void edscript(int) __dead2;
155 static void Ascript(int) __dead2;
156 static void mergescript(int) __dead2;
157 static void increase(void);
158 static void usage(void) __dead2;
159 static void printrange(FILE *, struct range *);
166 #define DIFF_PATH "/usr/bin/diff"
168 #define OPTIONS "3aAeEiL:mTxX"
169 static struct option longopts[] = {
170 { "ed", no_argument, NULL, 'e' },
171 { "show-overlap", no_argument, NULL, 'E' },
172 { "overlap-only", no_argument, NULL, 'x' },
173 { "initial-tab", no_argument, NULL, 'T' },
174 { "text", no_argument, NULL, 'a' },
175 { "strip-trailing-cr", no_argument, NULL, STRIPCR_OPT },
176 { "show-all", no_argument, NULL, 'A' },
177 { "easy-only", no_argument, NULL, '3' },
178 { "merge", no_argument, NULL, 'm' },
179 { "label", required_argument, NULL, 'L' },
180 { "diff-program", required_argument, NULL, DIFFPROG_OPT },
186 fprintf(stderr, "usage: diff3 [-3aAeEimTxX] [-L label1] [-L label2] "
187 "[-L label3] file1 file2 file3\n");
192 readin(int fd, struct diff **dd)
202 for (i = 0; (p = getchange(f)); i++) {
204 (*dd)[i].line = strdup(p);
207 if (i >= szchanges - 1)
209 a = b = (int)strtoimax(p, &p, 10);
212 b = (int)strtoimax(p, &p, 10);
215 c = d = (int)strtoimax(p, &p, 10);
218 d = (int)strtoimax(p, &p, 10);
226 (*dd)[i].old.from = a;
228 (*dd)[i].new.from = c;
232 (*dd)[i].old.from = (*dd)[i - 1].old.to;
233 (*dd)[i].new.from = (*dd)[i - 1].new.to;
240 diffexec(const char *diffprog, char **diffargv, int fd[])
244 switch (pdfork(&pd, PD_CLOEXEC)) {
247 if (dup2(fd[1], STDOUT_FILENO) == -1)
248 err(2, "child could not duplicate descriptor");
250 execvp(diffprog, diffargv);
251 err(2, "could not execute diff: %s", diffprog);
254 err(2, "could not fork");
266 while ((line = get_line(b, NULL))) {
267 if (isdigit((unsigned char)line[0]))
275 get_line(FILE *b, size_t *n)
278 static char *buf = NULL;
279 static size_t bufsize = 0;
281 if ((len = getline(&buf, &bufsize, b)) < 0)
284 if (strip_cr && len >= 2 && strcmp("\r\n", &(buf[len - 2])) == 0) {
297 merge(int m1, int m2)
299 struct diff *d1, *d2, *d3;
307 while ((t1 = d1 < d13 + m1) | (t2 = d2 < d23 + m2)) {
308 /* first file is different from the others */
309 if (!t2 || (t1 && d1->new.to < d2->new.from)) {
310 /* stuff peculiar to 1st file */
313 change(1, &d1->old, false);
315 change(3, &d1->new, false);
320 /* second file is different from others */
321 if (!t1 || (t2 && d2->new.to < d1->new.from)) {
325 change(3, &d2->new, false);
326 change(2, &d2->old, false);
327 } else if (Aflag || mflag) {
328 // XXX-THJ: What does it mean for the second file to differ?
329 j = edit(d2, dup, j, DIFF_TYPE2);
335 * Merge overlapping changes in first file
336 * this happens after extension (see below).
338 if (d1 + 1 < d13 + m1 && d1->new.to >= d1[1].new.from) {
339 d1[1].old.from = d1->old.from;
340 d1[1].new.from = d1->new.from;
345 /* merge overlapping changes in second */
346 if (d2 + 1 < d23 + m2 && d2->new.to >= d2[1].new.from) {
347 d2[1].old.from = d2->old.from;
348 d2[1].new.from = d2->new.from;
352 /* stuff peculiar to third file or different in all */
353 if (d1->new.from == d2->new.from && d1->new.to == d2->new.to) {
354 dup = duplicate(&d1->old, &d2->old);
356 * dup = 0 means all files differ
357 * dup = 1 means files 1 and 2 identical
360 printf("====%s\n", dup ? "3" : "");
361 change(1, &d1->old, dup);
362 change(2, &d2->old, false);
363 d3 = d1->old.to > d1->old.from ? d1 : d2;
364 change(3, &d3->new, false);
366 j = edit(d1, dup, j, DIFF_TYPE3);
374 * Overlapping changes from file 1 and 2; extend changes
375 * appropriately to make them coincide.
377 if (d1->new.from < d2->new.from) {
378 d2->old.from -= d2->new.from - d1->new.from;
379 d2->new.from = d1->new.from;
380 } else if (d2->new.from < d1->new.from) {
381 d1->old.from -= d1->new.from - d2->new.from;
382 d1->new.from = d2->new.from;
384 if (d1->new.to > d2->new.to) {
385 d2->old.to += d1->new.to - d2->new.to;
386 d2->new.to = d1->new.to;
387 } else if (d2->new.to > d1->new.to) {
388 d1->old.to += d2->new.to - d1->new.to;
389 d1->new.to = d2->new.to;
402 * The range of lines rold.from thru rold.to in file i is to be changed.
403 * It is to be printed only if it does not duplicate something to be
407 change(int i, struct range *rold, bool dup)
416 skip(i, rold->from, NULL);
417 skip(i, rold->to, " ");
421 * Print the range of line numbers, rold.from thru rold.to, as n1,n2 or
425 prange(struct range *rold, bool delete)
428 if (rold->to <= rold->from)
429 printf("%da\n", rold->from - 1);
431 printf("%d", rold->from);
432 if (rold->to > rold->from + 1)
433 printf(",%d", rold->to - 1);
442 * No difference was reported by diff between file 1 (or 2) and file 3,
443 * and an artificial dummy difference (trange) must be ginned up to
444 * correspond to the change reported in the other file.
447 keep(int i, struct range *rnew)
452 delta = last[3] - last[i];
453 trange.from = rnew->from - delta;
454 trange.to = rnew->to - delta;
455 change(i, &trange, true);
459 * skip to just before line number from in file "i". If "pr" is non-NULL,
460 * print all skipped stuff with string pr as a prefix.
463 skip(int i, int from, const char *pr)
468 for (n = 0; cline[i] < from - 1; n += j) {
469 if ((line = get_line(fp[i], &j)) == NULL)
470 errx(EXIT_FAILURE, "logic error");
472 printf("%s%s", Tflag == 1 ? "\t" : pr, line);
479 * Return 1 or 0 according as the old range (in file 1) contains exactly
480 * the same data as the new range (in file 2).
483 duplicate(struct range *r1, struct range *r2)
489 if (r1->to-r1->from != r2->to-r2->from)
491 skip(0, r1->from, NULL);
492 skip(1, r2->from, NULL);
494 for (nline = 0; nline < r1->to - r1->from; nline++) {
498 if (c == -1 && d == -1)
500 if (c == -1 || d == -1)
501 errx(EXIT_FAILURE, "logic error");
518 for (i = 0; i < 2; i++)
519 (void)fseek(fp[i], (long)-nchar, SEEK_CUR);
523 * collect an editing script for later regurgitation
526 edit(struct diff *diff, bool dup, int j, int difftype)
529 if (((dup + 1) & eflag) == 0)
536 de[j].type = difftype;
538 de[j].line = diff->line;
541 de[j].old.from = diff->old.from;
542 de[j].old.to = diff->old.to;
543 de[j].new.from = diff->new.from;
544 de[j].new.to = diff->new.to;
549 printrange(FILE *p, struct range *r)
556 /* We haven't been asked to print anything */
557 if (r->from == r->to)
561 errx(EXIT_FAILURE, "invalid print range");
564 * XXX-THJ: We read through all of the file for each range printed.
565 * This duplicates work and will probably impact performance on large
566 * files with lots of ranges.
568 fseek(p, 0L, SEEK_SET);
569 while ((rlen = getline(&line, &len, p)) > 0) {
585 delete = (de[n].new.from == de[n].new.to);
586 if (!oflag || !overlap[n]) {
587 prange(&de[n].old, delete);
589 printf("%da\n", de[n].old.to - 1);
592 printrange(fp[2], &de[n].new);
593 if (!oflag || !overlap[n]) {
597 printf("%s %s\n.\n", newmark, f3mark);
598 printf("%da\n%s %s\n.\n", de[n].old.from - 1,
605 exit(eflag == 0 ? overlapcnt : 0);
609 * Output an edit script to turn mine into yours, when there is a conflict
610 * between the 3 files bracket the changes. Regurgitate the diffs in reverse
611 * order to allow the ed script to track down where the lines are as changes
623 deletenew = (de[n].new.from == de[n].new.to);
624 deleteold = (de[n].old.from == de[n].old.to);
625 startmark = de[n].old.from + (de[n].old.to - de[n].old.from) - 1;
627 if (de[n].type == DIFF_TYPE2) {
628 if (!oflag || !overlap[n]) {
629 prange(&de[n].old, deletenew);
630 printrange(fp[2], &de[n].new);
632 startmark = de[n].new.from +
633 (de[n].new.to - de[n].new.from);
638 printf("%da\n", startmark);
639 printf("%s %s\n", newmark, f3mark);
643 printf("%da\n", startmark -
644 (de[n].new.to - de[n].new.from));
645 printf("%s %s\n", oldmark, f2mark);
647 printrange(fp[1], &de[n].old);
648 printf("=======\n.\n");
651 } else if (de[n].type == DIFF_TYPE3) {
652 if (!oflag || !overlap[n]) {
653 prange(&de[n].old, deletenew);
654 printrange(fp[2], &de[n].new);
656 printf("%da\n", startmark);
657 printf("%s %s\n", orgmark, f2mark);
661 r.from = de[n].old.from-1;
663 printrange(fp[1], &r);
665 printrange(fp[1], &de[n].old);
668 printrange(fp[2], &de[n].new);
671 if (!oflag || !overlap[n]) {
675 printf("%s %s\n.\n", newmark, f3mark);
678 * Go to the start of the conflict in original
679 * file and append lines
681 printf("%da\n%s %s\n.\n",
682 startmark - (de[n].old.to - de[n].old.from),
690 exit(overlapcnt > 0);
694 * Output the merged file directly (don't generate an ed script). When
695 * regurgitating diffs we need to walk forward through the file and print any
707 for (n = 1; n < i+1; n++) {
708 /* print any lines leading up to here */
709 r.to = de[n].old.from;
710 printrange(fp[0], &r);
712 if (de[n].type == DIFF_TYPE2) {
713 printf("%s %s\n", oldmark, f2mark);
714 printrange(fp[1], &de[n].old);
716 printrange(fp[2], &de[n].new);
717 printf("%s %s\n", newmark, f3mark);
718 } else if (de[n].type == DIFF_TYPE3) {
719 if (!oflag || !overlap[n]) {
720 printrange(fp[2], &de[n].new);
723 printf("%s %s\n", oldmark, f1mark);
724 printrange(fp[0], &de[n].old);
726 printf("%s %s\n", orgmark, f2mark);
727 if (de[n].old.from == de[n].old.to) {
729 or.from = de[n].old.from -1;
730 or.to = de[n].new.to;
731 printrange(fp[1], &or);
733 printrange(fp[1], &de[n].old);
737 printrange(fp[2], &de[n].new);
738 printf("%s %s\n", newmark, f3mark);
742 if (de[n].old.from == de[n].old.to)
743 r.from = de[n].new.to;
745 r.from = de[n].old.to;
748 * Print from the final range to the end of 'myfile'. Any deletions or
749 * additions to this file should have been handled by now.
751 * If the ranges are the same we need to rewind a line.
752 * If the new range is 0 length (from == to), we need to use the old
755 if ((de[n-1].old.from == de[n-1].new.from) &&
756 (de[n-1].old.to == de[n-1].new.to))
758 else if (de[n-1].new.from == de[n-1].new.to)
759 r.from = de[n-1].old.from;
762 * If the range is a 3 way merge then we need to skip a line in the
765 if (de[n-1].type == DIFF_TYPE3)
769 printrange(fp[0], &r);
770 exit(overlapcnt > 0);
780 /* are the memset(3) calls needed? */
781 newsz = szchanges == 0 ? 64 : 2 * szchanges;
782 incr = newsz - szchanges;
784 p = reallocarray(d13, newsz, sizeof(struct diff));
787 memset(p + szchanges, 0, incr * sizeof(struct diff));
789 p = reallocarray(d23, newsz, sizeof(struct diff));
792 memset(p + szchanges, 0, incr * sizeof(struct diff));
794 p = reallocarray(de, newsz, sizeof(struct diff));
797 memset(p + szchanges, 0, incr * sizeof(struct diff));
799 q = reallocarray(overlap, newsz, sizeof(char));
802 memset(q + szchanges, 0, incr * sizeof(char));
809 main(int argc, char **argv)
811 int ch, nblabels, status, m, n, kq, nke, nleft, i;
812 char *labels[] = { NULL, NULL, NULL };
813 const char *diffprog = DIFF_PATH;
814 char *file1, *file2, *file3;
817 int fd13[2], fd23[2];
819 cap_rights_t rights_ro;
825 diffargv[diffargc++] = __DECONST(char *, diffprog);
826 while ((ch = getopt_long(argc, argv, OPTIONS, longopts, NULL)) != -1) {
832 diffargv[diffargc++] = __DECONST(char *, "-a");
850 errx(2, "too many file label options");
851 labels[nblabels++] = optarg;
873 diffargv[diffargc++] = __DECONST(char *, "--strip-trailing-cr");
888 if (caph_limit_stdio() == -1)
889 err(2, "unable to limit stdio");
891 cap_rights_init(&rights_ro, CAP_READ, CAP_FSTAT, CAP_SEEK);
897 e = malloc(2 * sizeof(struct kevent));
907 asprintf(&f1mark, "%s",
908 labels[0] != NULL ? labels[0] : file1);
911 asprintf(&f2mark, "%s",
912 labels[1] != NULL ? labels[1] : file2);
915 asprintf(&f3mark, "%s",
916 labels[2] != NULL ? labels[2] : file3);
920 fp[0] = fopen(file1, "r");
922 err(2, "Can't open %s", file1);
923 if (caph_rights_limit(fileno(fp[0]), &rights_ro) < 0)
924 err(2, "unable to limit rights on: %s", file1);
926 fp[1] = fopen(file2, "r");
928 err(2, "Can't open %s", file2);
929 if (caph_rights_limit(fileno(fp[1]), &rights_ro) < 0)
930 err(2, "unable to limit rights on: %s", file2);
932 fp[2] = fopen(file3, "r");
934 err(2, "Can't open %s", file3);
935 if (caph_rights_limit(fileno(fp[2]), &rights_ro) < 0)
936 err(2, "unable to limit rights on: %s", file3);
943 diffargv[diffargc] = file1;
944 diffargv[diffargc + 1] = file3;
945 diffargv[diffargc + 2] = NULL;
948 pd13 = diffexec(diffprog, diffargv, fd13);
949 EV_SET(e + nleft , pd13, EVFILT_PROCDESC, EV_ADD, NOTE_EXIT, 0, NULL);
950 if (kevent(kq, e + nleft, 1, NULL, 0, NULL) == -1)
954 diffargv[diffargc] = file2;
955 pd23 = diffexec(diffprog, diffargv, fd23);
956 EV_SET(e + nleft , pd23, EVFILT_PROCDESC, EV_ADD, NOTE_EXIT, 0, NULL);
957 if (kevent(kq, e + nleft, 1, NULL, 0, NULL) == -1)
961 caph_cache_catpages();
962 if (caph_enter() < 0)
963 err(2, "unable to enter capability mode");
967 m = readin(fd13[0], &d13);
968 n = readin(fd23[0], &d23);
970 /* waitpid cooked over pdforks */
972 nke = kevent(kq, NULL, 0, e, nleft, NULL);
975 for (i = 0; i < nke; i++) {
977 if (WIFEXITED(status) && WEXITSTATUS(status) >= 2)
978 errx(2, "diff exited abnormally");
979 else if (WIFSIGNALED(status))
980 errx(2, "diff killed by signal %d",
987 return (EXIT_SUCCESS);