17 files changed, 1171 insertions, 0 deletions

diff --git a/usr.bin/diff3/Makefile b/usr.bin/diff3/Makefile
new file mode 100644
index 000000000000..a783e00a45ff
--- /dev/null
+++ b/usr.bin/diff3/Makefile
@@ -0,0 +1,11 @@
+# $FreeBSD$
+
+.include <src.opts.mk>
+
+PROG=	diff3
+
+.if ${MK_TESTS} != "no"
+SUBDIR+=	tests
+.endif
+
+.include <bsd.prog.mk>
diff --git a/usr.bin/diff3/diff3.1 b/usr.bin/diff3/diff3.1
new file mode 100644
index 000000000000..f7fda1636d13
--- /dev/null
+++ b/usr.bin/diff3/diff3.1
@@ -0,0 +1,202 @@
+.\" $OpenBSD: diff3.1,v 1.7 2007/05/31 19:20:09 jmc Exp $
+.\"
+.\" Copyright (c) 1990, 1993, 1994
+.\"	The Regents of the University of California.  All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\" 3. Neither the name of the University nor the names of its contributors
+.\"    may be used to endorse or promote products derived from this software
+.\"    without specific prior written permission.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.\"     @(#)diff3.1	8.2 (Berkeley) 4/18/94
+.\" $FreeBSD$
+.\"
+.Dd $Mdocdate: May 31 2007 $
+.Dt DIFF3 1
+.Os
+.Sh NAME
+.Nm diff3
+.Nd 3-way differential file comparison
+.Sh SYNOPSIS
+.Nm diff3
+.Op Fl 3aEeXx
+.Ar file1 file2 file3
+.Sh DESCRIPTION
+The
+.Nm
+utility compares the contents of three different versions of a file,
+.Ar file1 ,
+.Ar file2
+and
+.Ar file3 ,
+writing the result to the standard output.
+The options describe different methods of merging and
+purging
+the separate versions into a new file.
+.Nm
+is used by
+.Xr rcs 1
+to merge specific versions or create
+new versions.
+.Pp
+The options are as follows:
+.Bl -tag -width "-E, -X"
+.It Fl 3
+Produces an output script suitable for
+.Xr ed 1
+with changes
+specific only to
+.Ar file3 .
+.It Fl a
+Treat all files as ASCII.
+.It Fl E , X
+Similar to
+.Fl e
+and
+.Fl x ,
+respectively, but treat overlapping changes (i.e., changes that would
+be noted with ==== in the normal listing) differently.
+The overlapping lines from both files will be inserted by the edit script,
+bracketed by "<<<<<<" and ">>>>>>" lines.
+.It Fl e
+Produces output in a form suitable as an input script for the
+.Xr ed 1
+utility.
+The script may then be used to merge differences common between all
+three files and differences specific to
+.Ar file1
+and
+.Ar file3 .
+In other words, the
+.Fl e
+option ignores differences specific to
+.Ar file1
+and
+.Ar file2 ,
+and those specific to
+.Ar file2
+and
+.Ar file3 .
+It is useful for backing out changes specific to
+.Ar file2
+only.
+.It Fl x
+Produces an output script suitable for
+.Xr ed 1
+with changes
+specific only to all three versions.
+.El
+.Pp
+The
+.Fl E
+option is used by
+.Tn RCS
+.Xr merge 1
+to ensure that overlapping changes in the merged files are preserved
+and brought to someone's attention.
+.Pp
+For example, suppose lines 7-8 are changed in both
+.Ar file1
+and
+.Ar file2 .
+Applying the edit script generated by the command
+.Pp
+.Dl $ diff3 -E file1 file2 file3
+.Pp
+to
+.Ar file1
+results in the file:
+.Bd -literal -offset indent
+lines 1-6
+of file1
+<<<<<<< file1
+lines 7-8
+of file1
+=======
+lines 7-8
+of file3
+>>>>>>> file3
+rest of file1
+.Ed
+.Pp
+The default output of
+.Nm
+makes notation of the differences between all files, and those
+differences specific to each pair of files.
+The changes are described by the commands necessary for
+.Xr ed 1
+to create the desired target from the different versions.
+See
+.Xr diff 1
+for a description of the commands.
+.Bl -tag -width "====="
+.It Li \&====
+The lines beneath this notation are ranges of lines which are different
+between all files.
+.It \&==== Ns Va n
+The lines beneath this notation are ranges of lines which are exclusively
+different in file
+.Va n .
+.El
+.Sh ENVIRONMENT
+.Bl -tag -width TMPDIR
+.It Ev TMPDIR
+If the environment variable
+.Ev TMPDIR
+exists,
+.Nm
+will use the directory specified by
+.Ev TMPDIR
+as the temporary directory.
+.El
+.Sh FILES
+.Bl -tag -width /usr/libexec/diff3 -compact
+.It Pa /tmp/d3a.XXXXXXXXXX
+temporary file
+.It Pa /tmp/d3b.XXXXXXXXXX
+temporary file
+.It Pa /usr/libexec/diff3
+the actual executable
+.El
+.Sh SEE ALSO
+.Xr diff 1 ,
+.Xr ed 1 ,
+.Xr merge 1 ,
+.Xr rcs 1 ,
+.Xr sdiff 1
+.Sh HISTORY
+A
+.Nm
+command appeared in
+.At v7 .
+.Sh BUGS
+The
+.Fl e
+option cannot catch and change lines which have
+.Ql \&.
+as the first and only character on the line.
+The resulting script will fail on that line
+as
+.Ql \&.
+is an
+.Xr ed 1
+editing command.
diff --git a/usr.bin/diff3/diff3.c b/usr.bin/diff3/diff3.c
new file mode 100644
index 000000000000..0ec65710299f
--- /dev/null
+++ b/usr.bin/diff3/diff3.c
@@ -0,0 +1,787 @@
+/*	$OpenBSD: diff3prog.c,v 1.11 2009/10/27 23:59:37 deraadt Exp $	*/
+
+/*
+ * Copyright (C) Caldera International Inc.  2001-2002.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code and documentation must retain the above
+ *    copyright notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed or owned by Caldera
+ *	International, Inc.
+ * 4. Neither the name of Caldera International, Inc. nor the names of other
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * USE OF THE SOFTWARE PROVIDED FOR UNDER THIS LICENSE BY CALDERA
+ * INTERNATIONAL, INC. AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL CALDERA INTERNATIONAL, INC. BE LIABLE FOR ANY DIRECT,
+ * INDIRECT INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)diff3.c	8.1 (Berkeley) 6/6/93
+ */
+
+#if 0
+#ifndef lint
+static char sccsid[] = "@(#)diff3.c	8.1 (Berkeley) 6/6/93";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/capsicum.h>
+#include <sys/procdesc.h>
+#include <sys/types.h>
+#include <sys/event.h>
+#include <sys/wait.h>
+
+#include <capsicum_helpers.h>
+#include <ctype.h>
+#include <err.h>
+#include <getopt.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+
+/*
+ * "from" is first in range of changed lines; "to" is last+1
+ * from=to=line after point of insertion for added lines.
+ */
+struct range {
+	int from;
+	int to;
+};
+
+struct diff {
+	struct range old;
+	struct range new;
+};
+
+static size_t szchanges;
+
+static struct diff *d13;
+static struct diff *d23;
+/*
+ * "de" is used to gather editing scripts.  These are later spewed out in
+ * reverse order.  Its first element must be all zero, the "new" component
+ * of "de" contains line positions or byte positions depending on when you
+ * look (!?).  Array overlap indicates which sections in "de" correspond to
+ * lines that are different in all three files.
+ */
+static struct diff *de;
+static char *overlap;
+static int  overlapcnt;
+static FILE *fp[3];
+static int cline[3];		/* # of the last-read line in each file (0-2) */
+/*
+ * The latest known correspondence between line numbers of the 3 files
+ * is stored in last[1-3];
+ */
+static int last[4];
+static int Aflag, eflag, iflag, mflag, Tflag;
+static int oflag;		/* indicates whether to mark overlaps (-E or -X)*/
+static int strip_cr;
+static char *f1mark, *f2mark, *f3mark;
+
+static bool duplicate(struct range *, struct range *);
+static int edit(struct diff *, bool, int);
+static char *getchange(FILE *);
+static char *get_line(FILE *, size_t *);
+static int number(char **);
+static int readin(int fd, struct diff **);
+static int skip(int, int, const char *);
+static void change(int, struct range *, bool);
+static void keep(int, struct range *);
+static void merge(int, int);
+static void prange(struct range *);
+static void repos(int);
+static void edscript(int) __dead2;
+static void increase(void);
+static void usage(void) __dead2;
+
+enum {
+	DIFFPROG_OPT,
+	STRIPCR_OPT,
+};
+
+#define MAX_CHECK 768	/* 3 kb of chars */
+#define DIFF_PATH "/usr/bin/diff"
+
+
+#define OPTIONS "3aAeEiL:mTxX"
+static struct option longopts[] = {
+	{ "ed",			no_argument,		NULL,	'e' },
+	{ "show-overlap",	no_argument,		NULL,	'E' },
+	{ "overlap-only",	no_argument,		NULL,	'x' },
+	{ "initial-tab",	no_argument,		NULL,	'T' },
+	{ "text",		no_argument,		NULL,	'a' },
+	{ "strip-trailing-cr",	no_argument,		NULL,	STRIPCR_OPT },
+	{ "show-all",		no_argument,		NULL,	'A' },
+	{ "easy-only",		no_argument,		NULL,	'3' },
+	{ "merge",		no_argument,		NULL,	'm' },
+	{ "label",		required_argument,	NULL,	'L' },
+	{ "diff-program",	required_argument,	NULL,	DIFFPROG_OPT },
+};
+
+static void
+usage(void)
+{
+	fprintf(stderr, "usage: diff3 [-3aAeEimTxX] [-L lable1] [-L label2] "
+	    "[ -L label3] file1 file2 file3\n");
+	exit (2);
+}
+
+static int
+readin(int fd, struct diff **dd)
+{
+	int a, b, c, d;
+	size_t i;
+	char kind, *p;
+	FILE *f;
+
+	f = fdopen(fd, "r");
+	if (f == NULL)
+		err(2, "fdopen");
+	for (i=0; (p = getchange(f)); i++) {
+		if (i >= szchanges - 1)
+			increase();
+		a = b = number(&p);
+		if (*p == ',') {
+			p++;
+			b = number(&p);
+		}
+		kind = *p++;
+		c = d = number(&p);
+		if (*p==',') {
+			p++;
+			d = number(&p);
+		}
+		if (kind == 'a')
+			a++;
+		if (kind == 'd')
+			c++;
+		b++;
+		d++;
+		(*dd)[i].old.from = a;
+		(*dd)[i].old.to = b;
+		(*dd)[i].new.from = c;
+		(*dd)[i].new.to = d;
+	}
+	if (i) {
+		(*dd)[i].old.from = (*dd)[i-1].old.to;
+		(*dd)[i].new.from = (*dd)[i-1].new.to;
+	}
+	fclose(f);
+	return (i);
+}
+
+static int
+diffexec(const char *diffprog, char **diffargv, int fd[])
+{
+	int pid, pd;
+
+	switch (pid = pdfork(&pd, PD_CLOEXEC)) {
+	case 0:
+		close(fd[0]);
+		if (dup2(fd[1], STDOUT_FILENO) == -1)
+			err(2, "child could not duplicate descriptor");
+		close(fd[1]);
+		execvp(diffprog, diffargv);
+		err(2, "could not execute diff: %s", diffprog);
+		break;
+	case -1:
+		err(2, "could not fork");
+		break;
+	}
+	close(fd[1]);
+	return (pd);
+}
+
+static int
+number(char **lc)
+{
+	int nn;
+
+	nn = 0;
+	while (isdigit((unsigned char)(**lc)))
+		nn = nn*10 + *(*lc)++ - '0';
+	return (nn);
+}
+
+static char *
+getchange(FILE *b)
+{
+	char *line;
+
+	while ((line = get_line(b, NULL))) {
+		if (isdigit((unsigned char)line[0]))
+			return (line);
+	}
+	return (NULL);
+}
+
+
+static char *
+get_line(FILE *b, size_t *n)
+{
+	char *cp;
+	size_t len;
+	static char *buf;
+	static size_t bufsize;
+
+	if ((cp = fgetln(b, &len)) == NULL)
+		return (NULL);
+
+	if (cp[len - 1] != '\n')
+		len++;
+	if (len + 1 > bufsize) {
+		do {
+			bufsize += 1024;
+		} while (len + 1 > bufsize);
+		if ((buf = realloc(buf, bufsize)) == NULL)
+			err(EXIT_FAILURE, NULL);
+	}
+	memcpy(buf, cp, len - 1);
+	buf[len - 1] = '\n';
+	buf[len] = '\0';
+	if (n != NULL)
+		*n = len;
+	return (buf);
+}
+
+static void
+merge(int m1, int m2)
+{
+	struct diff *d1, *d2, *d3;
+	int j, t1, t2;
+	bool dup = false;
+
+	d1 = d13;
+	d2 = d23;
+	j = 0;
+
+	while ((t1 = d1 < d13 + m1) | (t2 = d2 < d23 + m2)) {
+		/* first file is different from the others */
+		if (!t2 || (t1 && d1->new.to < d2->new.from)) {
+			/* stuff peculiar to 1st file */
+			if (eflag == 0) {
+				printf("====1\n");
+				change(1, &d1->old, false);
+				keep(2, &d1->new);
+				change(3, &d1->new, false);
+			}
+			d1++;
+			continue;
+		}
+		/* second file is different from others */
+		if (!t1 || (t2 && d2->new.to < d1->new.from)) {
+			if (eflag == 0) {
+				printf("====2\n");
+				keep(1, &d2->new);
+				change(3, &d2->new, false);
+				change(2, &d2->old, false);
+			}
+			d2++;
+			continue;
+		}
+		/*
+		 * Merge overlapping changes in first file
+		 * this happens after extension (see below).
+		 */
+		if (d1 + 1 < d13 + m1 && d1->new.to >= d1[1].new.from) {
+			d1[1].old.from = d1->old.from;
+			d1[1].new.from = d1->new.from;
+			d1++;
+			continue;
+		}
+
+		/* merge overlapping changes in second */
+		if (d2 + 1 < d23 + m2 && d2->new.to >= d2[1].new.from) {
+			d2[1].old.from = d2->old.from;
+			d2[1].new.from = d2->new.from;
+			d2++;
+			continue;
+		}
+		/* stuff peculiar to third file or different in all */
+		if (d1->new.from == d2->new.from && d1->new.to == d2->new.to) {
+			dup = duplicate(&d1->old, &d2->old);
+			/*
+			 * dup = 0 means all files differ
+			 * dup = 1 means files 1 and 2 identical
+			 */
+			if (eflag == 0) {
+				printf("====%s\n", dup ? "3" : "");
+				change(1, &d1->old, dup);
+				change(2, &d2->old, false);
+				d3 = d1->old.to > d1->old.from ? d1 : d2;
+				change(3, &d3->new, false);
+			} else
+				j = edit(d1, dup, j);
+			d1++;
+			d2++;
+			continue;
+		}
+		/*
+		 * Overlapping changes from file 1 and 2; extend changes
+		 * appropriately to make them coincide.
+		 */
+		if (d1->new.from < d2->new.from) {
+			d2->old.from -= d2->new.from - d1->new.from;
+			d2->new.from = d1->new.from;
+		} else if (d2->new.from < d1->new.from) {
+			d1->old.from -= d1->new.from - d2->new.from;
+			d1->new.from = d2->new.from;
+		}
+		if (d1->new.to > d2->new.to) {
+			d2->old.to += d1->new.to - d2->new.to;
+			d2->new.to = d1->new.to;
+		} else if (d2->new.to > d1->new.to) {
+			d1->old.to += d2->new.to - d1->new.to;
+			d1->new.to = d2->new.to;
+		}
+	}
+	if (eflag)
+		edscript(j);
+}
+
+/*
+ * The range of lines rold.from thru rold.to in file i is to be changed.
+ * It is to be printed only if it does not duplicate something to be
+ * printed later.
+ */
+static void
+change(int i, struct range *rold, bool dup)
+{
+
+	printf("%d:", i);
+	last[i] = rold->to;
+	prange(rold);
+	if (dup)
+		return;
+	i--;
+	skip(i, rold->from, NULL);
+	skip(i, rold->to, "  ");
+}
+
+/*
+ * Print the range of line numbers, rold.from thru rold.to, as n1,n2 or 
+ * n1.
+ */
+static void
+prange(struct range *rold)
+{
+
+	if (rold->to <= rold->from)
+		printf("%da\n", rold->from - 1);
+	else {
+		printf("%d", rold->from);
+		if (rold->to > rold->from+1)
+			printf(",%d", rold->to - 1);
+		printf("c\n");
+	}
+}
+
+/*
+ * No difference was reported by diff between file 1 (or 2) and file 3,
+ * and an artificial dummy difference (trange) must be ginned up to
+ * correspond to the change reported in the other file.
+ */
+static void
+keep(int i, struct range *rnew)
+{
+	int delta;
+	struct range trange;
+
+	delta = last[3] - last[i];
+	trange.from = rnew->from - delta;
+	trange.to = rnew->to - delta;
+	change(i, &trange, true);
+}
+
+/*
+ * skip to just before line number from in file "i".  If "pr" is non-NULL,
+ * print all skipped stuff with string pr as a prefix.
+ */
+static int
+skip(int i, int from, const char *pr)
+{
+	size_t j, n;
+	char *line;
+
+	for (n = 0; cline[i] < from - 1; n += j) {
+		if ((line = get_line(fp[i], &j)) == NULL)
+			errx(EXIT_FAILURE, "logic error");
+		if (pr != NULL)
+			printf("%s%s", Tflag == 1? "\t" : pr, line);
+		cline[i]++;
+	}
+	return ((int) n);
+}
+
+/*
+ * Return 1 or 0 according as the old range (in file 1) contains exactly
+ * the same data as the new range (in file 2).
+ */
+static bool
+duplicate(struct range *r1, struct range *r2)
+{
+	int c, d;
+	int nchar;
+	int nline;
+
+	if (r1->to-r1->from != r2->to-r2->from)
+		return (0);
+	skip(0, r1->from, NULL);
+	skip(1, r2->from, NULL);
+	nchar = 0;
+	for (nline=0; nline < r1->to - r1->from; nline++) {
+		do {
+			c = getc(fp[0]);
+			d = getc(fp[1]);
+			if (c == -1 || d== -1)
+				errx(EXIT_FAILURE, "logic error");
+			nchar++;
+			if (c != d) {
+				repos(nchar);
+				return (0);
+			}
+		} while (c != '\n');
+	}
+	repos(nchar);
+	return (1);
+}
+
+static void
+repos(int nchar)
+{
+	int i;
+
+	for (i = 0; i < 2; i++)
+		(void)fseek(fp[i], (long)-nchar, SEEK_CUR);
+}
+/*
+ * collect an editing script for later regurgitation
+ */
+static int
+edit(struct diff *diff, bool dup, int j)
+{
+
+	if (((dup + 1) & eflag) == 0)
+		return (j);
+	j++;
+	overlap[j] = !dup;
+	if (!dup)
+		overlapcnt++;
+	de[j].old.from = diff->old.from;
+	de[j].old.to = diff->old.to;
+	de[j].new.from = de[j-1].new.to + skip(2, diff->new.from, NULL);
+	de[j].new.to = de[j].new.from + skip(2, diff->new.to, NULL);
+	return (j);
+}
+
+/* regurgitate */
+static void
+edscript(int n)
+{
+	int k;
+	size_t j;
+	char block[BUFSIZ];
+
+	for (; n > 0; n--) {
+		if (!oflag || !overlap[n]) {
+			prange(&de[n].old);
+		} else {
+			printf("%da\n", de[n].old.to -1);
+			if (Aflag) {
+				printf("%s\n", f2mark);
+				fseek(fp[1], de[n].old.from, SEEK_SET);
+				for (k = de[n].old.to - de[n].old.from; k > 0; k -= j) {
+					j = k > BUFSIZ ? BUFSIZ : k;
+					if (fread(block, 1, j, fp[1]) != j)
+						errx(2, "logic error");
+					fwrite(block, 1, j, stdout);
+				}
+				printf("\n");
+			}
+			printf("=======\n");
+		}
+		fseek(fp[2], (long)de[n].new.from, SEEK_SET);
+		for (k = de[n].new.to - de[n].new.from; k > 0; k-= j) {
+			j = k > BUFSIZ ? BUFSIZ : k;
+			if (fread(block, 1, j, fp[2]) != j)
+				errx(2, "logic error");
+			fwrite(block, 1, j, stdout);
+		}
+		if (!oflag || !overlap[n])
+			printf(".\n");
+		else {
+			printf("%s\n.\n", f3mark);
+			printf("%da\n%s\n.\n", de[n].old.from - 1, f1mark);
+		}
+	}
+	if (iflag)
+		printf("w\nq\n");
+
+	exit(eflag == 0 ? overlapcnt : 0);
+}
+
+static void
+increase(void)
+{
+	struct diff *p;
+	char *q;
+	size_t newsz, incr;
+
+	/* are the memset(3) calls needed? */
+	newsz = szchanges == 0 ? 64 : 2 * szchanges;
+	incr = newsz - szchanges;
+
+	p = realloc(d13, newsz * sizeof(struct diff));
+	if (p == NULL)
+		err(1, NULL);
+	memset(p + szchanges, 0, incr * sizeof(struct diff));
+	d13 = p;
+	p = realloc(d23, newsz * sizeof(struct diff));
+	if (p == NULL)
+		err(1, NULL);
+	memset(p + szchanges, 0, incr * sizeof(struct diff));
+	d23 = p;
+	p = realloc(de, newsz * sizeof(struct diff));
+	if (p == NULL)
+		err(1, NULL);
+	memset(p + szchanges, 0, incr * sizeof(struct diff));
+	de = p;
+	q = realloc(overlap, newsz * sizeof(char));
+	if (q == NULL)
+		err(1, NULL);
+	memset(q + szchanges, 0, incr * sizeof(char));
+	overlap = q;
+	szchanges = newsz;
+}
+
+
+int
+main(int argc, char **argv)
+{
+	int ch, nblabels, status, m, n, kq, nke, nleft, i;
+	char *labels[] = { NULL, NULL, NULL };
+	const char *diffprog = DIFF_PATH;
+	char *file1, *file2, *file3;
+	char *diffargv[6];
+	int diffargc = 0;
+	int fd13[2], fd23[2];
+	int pd13, pd23;
+	cap_rights_t rights_ro;
+	struct kevent *e;
+
+	nblabels = 0;
+	eflag = 0;
+	oflag = 0;
+	diffargv[diffargc++] = __DECONST(char *, diffprog);
+	while ((ch = getopt_long(argc, argv, OPTIONS, longopts, NULL)) != -1) {
+		switch (ch) {
+		case '3':
+			eflag = 2;
+			break;
+		case 'a':
+			diffargv[diffargc++] = __DECONST(char *, "-a");
+			break;
+		case 'A':
+			Aflag = 1;
+			break;
+		case 'e':
+			eflag = 3;
+			break;
+		case 'E':
+			eflag = 3;
+			oflag = 1;
+			break;
+		case 'i':
+			iflag = 1;
+			break;
+		case 'L':
+			oflag = 1;
+			if (nblabels >= 3)
+				errx(2, "too many file label options");
+			labels[nblabels++] = optarg;
+			break;
+		case 'm':
+			Aflag = 1;
+			oflag = 1;
+			mflag = 1;
+			break;
+		case 'T':
+			Tflag = 1;
+			break;
+		case 'x':
+			eflag = 1;
+			break;
+		case 'X':
+			oflag = 1;
+			eflag = 1;
+			break;
+		case DIFFPROG_OPT:
+			diffprog = optarg;
+			break;
+		case STRIPCR_OPT:
+			strip_cr = 1;
+			break;
+		}
+	}
+	argc -= optind;
+	argv += optind;
+
+	if (Aflag) {
+		eflag = 3;
+		oflag = 1;
+	}
+
+	if (argc != 3)
+		usage();
+
+	if (caph_limit_stdio() == -1)
+		err(2, "unable to limit stdio");
+
+	cap_rights_init(&rights_ro, CAP_READ, CAP_FSTAT, CAP_SEEK);
+
+	kq = kqueue();
+	if (kq == -1)
+		err(2, "kqueue");
+
+	e = malloc(2 * sizeof(struct kevent));
+	if (e == NULL)
+		err(2, "malloc");
+
+	/* TODO stdio */
+	file1 = argv[0];
+	file2 = argv[1];
+	file3 = argv[2];
+
+	if (oflag) {
+		asprintf(&f1mark, "<<<<<<< %s",
+		    labels[0] != NULL ? labels[0] : file1);
+		if (f1mark == NULL)
+			err(2, "asprintf");
+		asprintf(&f2mark, "||||||| %s",
+		    labels[1] != NULL ? labels[1] : file2);
+		if (f2mark == NULL)
+			err(2, "asprintf");
+		asprintf(&f3mark, ">>>>>>> %s",
+		    labels[2] != NULL ? labels[2] : file3);
+		if (f3mark == NULL)
+			err(2, "asprintf");
+	}
+	fp[0] = fopen(file1, "r");
+	if (fp[0] == NULL)
+		err(2, "Can't open %s", file1);
+	if (cap_rights_limit(fileno(fp[0]), &rights_ro) < 0)
+		err(2, "unable to limit rights on: %s", file1);
+
+	fp[1] = fopen(file2, "r");
+	if (fp[1] == NULL)
+		err(2, "Can't open %s", file2);
+	if (cap_rights_limit(fileno(fp[1]), &rights_ro) < 0)
+		err(2, "unable to limit rights on: %s", file2);
+
+	fp[2] = fopen(file3, "r");
+	if (fp[2] == NULL)
+		err(2, "Can't open %s", file3);
+	if (cap_rights_limit(fileno(fp[2]), &rights_ro) < 0)
+		err(2, "unable to limit rights on: %s", file3);
+
+	if (pipe(fd13))
+		err(2, "pipe");
+	if (pipe(fd23))
+		err(2, "pipe");
+
+	diffargv[diffargc] = file1;
+	diffargv[diffargc + 1] = file3;
+	diffargv[diffargc + 2] = NULL;
+
+	nleft = 0;
+	pd13 = diffexec(diffprog, diffargv, fd13);
+	EV_SET(e + nleft , pd13, EVFILT_PROCDESC, EV_ADD, NOTE_EXIT, 0, NULL);
+	if (kevent(kq, e + nleft, 1, NULL, 0, NULL) == -1)
+		err(2, "kevent1");
+	nleft++;
+
+	diffargv[diffargc] = file2;
+	pd23 = diffexec(diffprog, diffargv, fd23);
+	EV_SET(e + nleft , pd23, EVFILT_PROCDESC, EV_ADD, NOTE_EXIT, 0, NULL);
+	if (kevent(kq, e + nleft, 1, NULL, 0, NULL) == -1)
+		err(2, "kevent2");
+	nleft++;
+
+	caph_cache_catpages();
+	if (cap_enter() < 0 && errno != ENOSYS)
+		err(2, "unable to enter capability mode");
+
+	/* parse diffs */
+	increase();
+	m = readin(fd13[0], &d13);
+	n = readin(fd23[0], &d23);
+
+	/* waitpid cooked over pdforks */
+	while (nleft > 0) {
+		nke = kevent(kq, NULL, 0, e, nleft, NULL);
+		if (nke == -1)
+			err(2, "kevent");
+		for (i = 0; i < nke; i++) {
+			status = e[i].data;
+			if (WIFEXITED(status) && WEXITSTATUS(status) >= 2)
+				errx(2, "diff exited abormally");
+			else if (WIFSIGNALED(status))
+				errx(2, "diff killed by signal %d",
+				    WTERMSIG(status));
+		}
+		nleft -= nke;
+	}
+	merge(m, n);
+
+	return (EXIT_SUCCESS);
+}
diff --git a/usr.bin/diff3/tests/1.out b/usr.bin/diff3/tests/1.out
new file mode 100644
index 000000000000..9b872bf3a880
--- /dev/null
+++ b/usr.bin/diff3/tests/1.out
@@ -0,0 +1,14 @@
+====
+1:2,3c
+  which multiple lines
+  and a few typ0s to fix
+2:2,3c
+  which multiple lines
+  and a few typos to fix
+3:2c
+  and a few typ0s to fix
+====2
+1:4a
+3:3a
+2:5c
+  New line
diff --git a/usr.bin/diff3/tests/1.txt b/usr.bin/diff3/tests/1.txt
new file mode 100644
index 000000000000..f0cd8062a6f1
--- /dev/null
+++ b/usr.bin/diff3/tests/1.txt
@@ -0,0 +1,6 @@
+This is a more complete test
+which multiple lines
+and a few typ0s to fix
+also I plan to add few lines
+    and to remove
+other lines
diff --git a/usr.bin/diff3/tests/2.out b/usr.bin/diff3/tests/2.out
new file mode 100644
index 000000000000..420dc4784b80
--- /dev/null
+++ b/usr.bin/diff3/tests/2.out
@@ -0,0 +1,3 @@
+2,3c
+and a few typ0s to fix
+.
diff --git a/usr.bin/diff3/tests/2.txt b/usr.bin/diff3/tests/2.txt
new file mode 100644
index 000000000000..990aa6f345c6
--- /dev/null
+++ b/usr.bin/diff3/tests/2.txt
@@ -0,0 +1,7 @@
+This is a more complete test
+which multiple lines
+and a few typos to fix
+also I plan to add few lines
+New line
+    and to remove
+other lines
diff --git a/usr.bin/diff3/tests/3.out b/usr.bin/diff3/tests/3.out
new file mode 100644
index 000000000000..81509d4ca510
--- /dev/null
+++ b/usr.bin/diff3/tests/3.out
@@ -0,0 +1,8 @@
+3a
+=======
+and a few typ0s to fix
+>>>>>>> 3
+.
+1a
+<<<<<<< 1
+.
diff --git a/usr.bin/diff3/tests/3.txt b/usr.bin/diff3/tests/3.txt
new file mode 100644
index 000000000000..104466e49690
--- /dev/null
+++ b/usr.bin/diff3/tests/3.txt
@@ -0,0 +1,5 @@
+This is a more complete test
+and a few typ0s to fix
+also I plan to add few lines
+    and to remove
+other lines
diff --git a/usr.bin/diff3/tests/4.out b/usr.bin/diff3/tests/4.out
new file mode 100644
index 000000000000..81509d4ca510
--- /dev/null
+++ b/usr.bin/diff3/tests/4.out
@@ -0,0 +1,8 @@
+3a
+=======
+and a few typ0s to fix
+>>>>>>> 3
+.
+1a
+<<<<<<< 1
+.
diff --git a/usr.bin/diff3/tests/5.out b/usr.bin/diff3/tests/5.out
new file mode 100644
index 000000000000..420dc4784b80
--- /dev/null
+++ b/usr.bin/diff3/tests/5.out
@@ -0,0 +1,3 @@
+2,3c
+and a few typ0s to fix
+.
diff --git a/usr.bin/diff3/tests/6.out b/usr.bin/diff3/tests/6.out
new file mode 100644
index 000000000000..e69de29bb2d1
--- /dev/null
+++ b/usr.bin/diff3/tests/6.out
diff --git a/usr.bin/diff3/tests/7.out b/usr.bin/diff3/tests/7.out
new file mode 100644
index 000000000000..9b872bf3a880
--- /dev/null
+++ b/usr.bin/diff3/tests/7.out
@@ -0,0 +1,14 @@
+====
+1:2,3c
+  which multiple lines
+  and a few typ0s to fix
+2:2,3c
+  which multiple lines
+  and a few typos to fix
+3:2c
+  and a few typ0s to fix
+====2
+1:4a
+3:3a
+2:5c
+  New line
diff --git a/usr.bin/diff3/tests/8.out b/usr.bin/diff3/tests/8.out
new file mode 100644
index 000000000000..5d02326ed7d1
--- /dev/null
+++ b/usr.bin/diff3/tests/8.out
@@ -0,0 +1,19 @@
+4a
+>>>>>>> 3
+.
+4a
+<<<<<<< 2
+New line
+=======
+.
+3a
+||||||| 2
+which multiple lines
+and a few typos to fix
+=======
+and a few typ0s to fix
+>>>>>>> 3
+.
+1a
+<<<<<<< 1
+.
diff --git a/usr.bin/diff3/tests/9.out b/usr.bin/diff3/tests/9.out
new file mode 100644
index 000000000000..2071bab4ce07
--- /dev/null
+++ b/usr.bin/diff3/tests/9.out
@@ -0,0 +1,17 @@
+This is a more complete test
+<<<<<<< 1
+which multiple lines
+and a few typ0s to fix
+||||||| 2
+which multiple lines
+and a few typos to fix
+=======
+and a few typ0s to fix
+>>>>>>> 3
+also I plan to add few lines
+<<<<<<< 2
+New line
+=======
+>>>>>>> 3
+    and to remove
+other lines
diff --git a/usr.bin/diff3/tests/Makefile b/usr.bin/diff3/tests/Makefile
new file mode 100644
index 000000000000..dd75be1ca02a
--- /dev/null
+++ b/usr.bin/diff3/tests/Makefile
@@ -0,0 +1,21 @@
+# $FreeBSD$
+
+PACKAGE=	tests
+
+ATF_TESTS_SH=	diff3_test
+
+${PACKAGE}FILES+=	\
+	1.txt \
+	2.txt \
+	3.txt \
+	1.out \
+	2.out \
+	3.out \
+	4.out \
+	5.out \
+	6.out \
+	7.out \
+	8.out \
+	9.out
+
+.include <bsd.test.mk>
diff --git a/usr.bin/diff3/tests/diff3_test.sh b/usr.bin/diff3/tests/diff3_test.sh
new file mode 100755
index 000000000000..9911e7c16432
--- /dev/null
+++ b/usr.bin/diff3/tests/diff3_test.sh
@@ -0,0 +1,46 @@
+# $FreeBSD$
+
+atf_test_case diff3
+atf_test_case diff3_lesssimple
+
+diff3_body()
+{
+	atf_check -o file:$(atf_get_srcdir)/1.out \
+		diff3 $(atf_get_srcdir)/1.txt $(atf_get_srcdir)/2.txt $(atf_get_srcdir)/3.txt
+
+	atf_check -o file:$(atf_get_srcdir)/2.out \
+		diff3 -e $(atf_get_srcdir)/1.txt $(atf_get_srcdir)/2.txt $(atf_get_srcdir)/3.txt
+
+	atf_check -o file:$(atf_get_srcdir)/3.out \
+		diff3 -E -L 1 -L 2 -L 3 $(atf_get_srcdir)/1.txt $(atf_get_srcdir)/2.txt $(atf_get_srcdir)/3.txt
+
+	atf_check -o file:$(atf_get_srcdir)/4.out \
+		diff3 -X -L 1 -L 2 -L 3 $(atf_get_srcdir)/1.txt $(atf_get_srcdir)/2.txt $(atf_get_srcdir)/3.txt
+
+	atf_check -o file:$(atf_get_srcdir)/5.out \
+		diff3 -x $(atf_get_srcdir)/1.txt $(atf_get_srcdir)/2.txt $(atf_get_srcdir)/3.txt
+
+	atf_check -o file:$(atf_get_srcdir)/6.out \
+		diff3 -3 $(atf_get_srcdir)/1.txt $(atf_get_srcdir)/2.txt $(atf_get_srcdir)/3.txt
+
+	atf_check -o file:$(atf_get_srcdir)/7.out \
+		diff3 -i $(atf_get_srcdir)/1.txt $(atf_get_srcdir)/2.txt $(atf_get_srcdir)/3.txt
+
+	atf_check -o file:$(atf_get_srcdir)/8.out \
+		diff3 -A -L 1 -L 2 -L 3 $(atf_get_srcdir)/1.txt $(atf_get_srcdir)/2.txt $(atf_get_srcdir)/3.txt
+
+	atf_check -s exit:1 -o file:$(atf_get_srcdir)/9.out \
+		diff3 -m -L 1 -L 2 -L 3 $(atf_get_srcdir)/1.txt $(atf_get_srcdir)/2.txt $(atf_get_srcdir)/3.txt
+}
+
+diff3_lesssimple_body()
+{
+	atf_check -s exit:1 -o file:$(atf_get_srcdir)/10.out \
+		diff3 -m -L 1 -L 2 -L 3 $(atf_get_srcdir)/4.txt $(atf_get_srcdir)/5.txt $(atf_get_srcdir)/6.txt
+}
+
+atf_init_test_cases()
+{
+	atf_add_test_case diff3
+	atf_add_test_case diff3_lesssimple
+}