/*      $OpenBSD: rcsdiff.c,v 1.85 2019/06/28 13:35:03 deraadt Exp $    */
/*
 * Copyright (c) 2005 Joris Vink <joris@openbsd.org>
 * 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. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED ``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 AUTHOR 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.
 */

#include <sys/stat.h>
#include <sys/time.h>

#include <err.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "rcsprog.h"
#include "diff.h"

static int rcsdiff_file(RCSFILE *, RCSNUM *, const char *, int);
static int rcsdiff_rev(RCSFILE *, RCSNUM *, RCSNUM *, int);
static void push_ignore_pats(char *);

static int quiet;
static int kflag = RCS_KWEXP_ERR;
static char *diff_ignore_pats;

int
rcsdiff_main(int argc, char **argv)
{
        int fd, i, ch, dflags, status;
        RCSNUM *rev1, *rev2;
        RCSFILE *file;
        char fpath[PATH_MAX], *rev_str1, *rev_str2;
        const char *errstr;

        rev1 = rev2 = NULL;
        rev_str1 = rev_str2 = NULL;
        status = D_SAME;
        dflags = 0;

        if (strlcpy(diffargs, "diff", sizeof(diffargs)) >= sizeof(diffargs))
                errx(D_ERROR, "diffargs too long");

        while ((ch = rcs_getopt(argc, argv, "abC:cdI:ik:npqr:TtU:uVwx::z::")) != -1) {
                switch (ch) {
                case 'a':
                        if (strlcat(diffargs, " -a", sizeof(diffargs)) >=
                            sizeof(diffargs))
                                errx(D_ERROR, "diffargs too long");
                        dflags |= D_FORCEASCII;
                        break;
                case 'b':
                        if (strlcat(diffargs, " -b", sizeof(diffargs)) >=
                            sizeof(diffargs))
                                errx(D_ERROR, "diffargs too long");
                        dflags |= D_FOLDBLANKS;
                        break;
                case 'C':
                        (void)strlcat(diffargs, " -C", sizeof(diffargs));
                        if (strlcat(diffargs, rcs_optarg, sizeof(diffargs)) >=
                            sizeof(diffargs))
                                errx(D_ERROR, "diffargs too long");
                        diff_context = strtonum(rcs_optarg, 0, INT_MAX, &errstr);
                        if (errstr)
                                errx(D_ERROR, "context is %s: %s",
                                    errstr, rcs_optarg);
                        diff_format = D_CONTEXT;
                        break;
                case 'c':
                        if (strlcat(diffargs, " -c", sizeof(diffargs)) >=
                            sizeof(diffargs))
                                errx(D_ERROR, "diffargs too long");
                        diff_format = D_CONTEXT;
                        break;
                case 'd':
                        if (strlcat(diffargs, " -d", sizeof(diffargs)) >=
                            sizeof(diffargs))
                                errx(D_ERROR, "diffargs too long");
                        dflags |= D_MINIMAL;
                        break;
                case 'i':
                        if (strlcat(diffargs, " -i", sizeof(diffargs)) >=
                            sizeof(diffargs))
                                errx(D_ERROR, "diffargs too long");
                        dflags |= D_IGNORECASE;
                        break;
                case 'I':
                        (void)strlcat(diffargs, " -I", sizeof(diffargs));
                        if (strlcat(diffargs, rcs_optarg, sizeof(diffargs)) >=
                            sizeof(diffargs))
                                errx(D_ERROR, "diffargs too long");
                        push_ignore_pats(rcs_optarg);
                        break;
                case 'k':
                        kflag = rcs_kflag_get(rcs_optarg);
                        if (RCS_KWEXP_INVAL(kflag)) {
                                warnx("invalid RCS keyword substitution mode");
                                (usage)();
                        }
                        break;
                case 'n':
                        if (strlcat(diffargs, " -n", sizeof(diffargs)) >=
                            sizeof(diffargs))
                                errx(D_ERROR, "diffargs too long");
                        diff_format = D_RCSDIFF;
                        break;
                case 'p':
                        if (strlcat(diffargs, " -p", sizeof(diffargs)) >=
                            sizeof(diffargs))
                                errx(D_ERROR, "diffargs too long");
                        dflags |= D_PROTOTYPE;
                        break;
                case 'q':
                        quiet = 1;
                        break;
                case 'r':
                        rcs_setrevstr2(&rev_str1, &rev_str2, rcs_optarg);
                        break;
                case 'T':
                        /*
                         * kept for compatibility
                         */
                        break;
                case 't':
                        if (strlcat(diffargs, " -t", sizeof(diffargs)) >=
                            sizeof(diffargs))
                                errx(D_ERROR, "diffargs too long");
                        dflags |= D_EXPANDTABS;
                        break;
                case 'U':
                        (void)strlcat(diffargs, " -U", sizeof(diffargs));
                        if (strlcat(diffargs, rcs_optarg, sizeof(diffargs)) >=
                            sizeof(diffargs))
                                errx(D_ERROR, "diffargs too long");
                        diff_context = strtonum(rcs_optarg, 0, INT_MAX, &errstr);
                        if (errstr)
                                errx(D_ERROR, "context is %s: %s",
                                    errstr, rcs_optarg);
                        diff_format = D_UNIFIED;
                        break;
                case 'u':
                        if (strlcat(diffargs, " -u", sizeof(diffargs)) >=
                            sizeof(diffargs))
                                errx(D_ERROR, "diffargs too long");
                        diff_format = D_UNIFIED;
                        break;
                case 'V':
                        printf("%s\n", rcs_version);
                        exit(0);
                case 'w':
                        if (strlcat(diffargs, " -w", sizeof(diffargs)) >=
                            sizeof(diffargs))
                                errx(D_ERROR, "diffargs too long");
                        dflags |= D_IGNOREBLANKS;
                        break;
                case 'x':
                        /* Use blank extension if none given. */
                        rcs_suffixes = rcs_optarg ? rcs_optarg : "";
                        break;
                case 'z':
                        timezone_flag = rcs_optarg;
                        break;
                default:
                        (usage)();
                }
        }

        argc -= rcs_optind;
        argv += rcs_optind;

        if (argc == 0) {
                warnx("no input file");
                (usage)();
        }

        if (diff_ignore_pats != NULL) {
                char buf[BUFSIZ];
                int error;

                diff_ignore_re = xmalloc(sizeof(*diff_ignore_re));
                if ((error = regcomp(diff_ignore_re, diff_ignore_pats,
                    REG_NEWLINE | REG_EXTENDED)) != 0) {
                        regerror(error, diff_ignore_re, buf, sizeof(buf));
                        if (*diff_ignore_pats != '\0')
                                errx(D_ERROR, "%s: %s", diff_ignore_pats, buf);
                        else
                                errx(D_ERROR, "%s", buf);
                }
        }

        for (i = 0; i < argc; i++) {
                fd = rcs_choosefile(argv[i], fpath, sizeof(fpath));
                if (fd < 0) {
                        warn("%s", fpath);
                        continue;
                }

                if ((file = rcs_open(fpath, fd,
                    RCS_READ|RCS_PARSE_FULLY)) == NULL)
                        continue;

                rcs_kwexp_set(file, kflag);

                if (rev_str1 != NULL) {
                        if ((rev1 = rcs_getrevnum(rev_str1, file)) == NULL)
                                errx(D_ERROR, "bad revision number");
                }
                if (rev_str2 != NULL) {
                        if ((rev2 = rcs_getrevnum(rev_str2, file)) == NULL)
                                errx(D_ERROR, "bad revision number");
                }

                if (!quiet) {
                        fprintf(stderr, "%s\n", RCS_DIFF_DIV);
                        fprintf(stderr, "RCS file: %s\n", fpath);
                }

                diff_file = argv[i];

                /* No revisions given. */
                if (rev_str1 == NULL)
                        status = rcsdiff_file(file, file->rf_head, argv[i],
                            dflags);
                /* One revision given. */
                else if (rev_str2 == NULL)
                        status = rcsdiff_file(file, rev1, argv[i], dflags);
                /* Two revisions given. */
                else
                        status = rcsdiff_rev(file, rev1, rev2, dflags);

                rcs_close(file);
                rcsnum_free(rev1);
                rcsnum_free(rev2);
                rev1 = rev2 = NULL;
        }

        return (status);
}

__dead void
rcsdiff_usage(void)
{
        fprintf(stderr,
            "usage: rcsdiff [-cnquV] [-kmode] [-rrev] [-xsuffixes] [-ztz]\n"
            "               [diff_options] file ...\n");

        exit(D_ERROR);
}

static int
rcsdiff_file(RCSFILE *file, RCSNUM *rev, const char *filename, int dflags)
{
        int ret, fd;
        time_t t;
        struct stat st;
        char *path1, *path2;
        BUF *b1, *b2;
        char rbuf[RCS_REV_BUFSZ];
        struct tm *tb;
        struct timeval tv[2], tv2[2];

        memset(&tv, 0, sizeof(tv));
        memset(&tv2, 0, sizeof(tv2));

        ret = D_ERROR;
        b1 = b2 = NULL;

        diff_rev1 = rev;
        diff_rev2 = NULL;
        path1 = path2 = NULL;

        if ((fd = open(filename, O_RDONLY)) == -1) {
                warn("%s", filename);
                goto out;
        }

        rcsnum_tostr(rev, rbuf, sizeof(rbuf));
        if (!quiet) {
                fprintf(stderr, "retrieving revision %s\n", rbuf);
                fprintf(stderr, "%s -r%s %s\n", diffargs, rbuf, filename);
        }

        if ((b1 = rcs_getrev(file, rev)) == NULL) {
                warnx("failed to retrieve revision %s", rbuf);
                goto out;
        }

        b1 = rcs_kwexp_buf(b1, file, rev);
        tv[0].tv_sec = rcs_rev_getdate(file, rev);
        tv[1].tv_sec = tv[0].tv_sec;

        if ((b2 = buf_load(filename)) == NULL) {
                warnx("failed to load file: `%s'", filename);
                goto out;
        }

        /* XXX - GNU uses GMT */
        if (fstat(fd, &st) == -1)
                err(D_ERROR, "%s", filename);

        tb = gmtime(&st.st_mtime);
        t = mktime(tb);

        tv2[0].tv_sec = t;
        tv2[1].tv_sec = t;

        (void)xasprintf(&path1, "%s/diff1.XXXXXXXXXX", rcs_tmpdir);
        buf_write_stmp(b1, path1);

        buf_free(b1);
        b1 = NULL;

        if (utimes(path1, (const struct timeval *)&tv) == -1)
                warn("utimes");

        (void)xasprintf(&path2, "%s/diff2.XXXXXXXXXX", rcs_tmpdir);
        buf_write_stmp(b2, path2);

        buf_free(b2);
        b2 = NULL;

        if (utimes(path2, (const struct timeval *)&tv2) == -1)
                warn("utimes");

        ret = diffreg(path1, path2, NULL, dflags);

out:
        if (fd != -1)
                (void)close(fd);
        buf_free(b1);
        buf_free(b2);
        free(path1);
        free(path2);

        return (ret);
}

static int
rcsdiff_rev(RCSFILE *file, RCSNUM *rev1, RCSNUM *rev2, int dflags)
{
        struct timeval tv[2], tv2[2];
        BUF *b1, *b2;
        int ret;
        char *path1, *path2, rbuf1[RCS_REV_BUFSZ], rbuf2[RCS_REV_BUFSZ];

        ret = D_ERROR;
        b1 = b2 = NULL;
        memset(&tv, 0, sizeof(tv));
        memset(&tv2, 0, sizeof(tv2));

        diff_rev1 = rev1;
        diff_rev2 = rev2;
        path1 = path2 = NULL;

        rcsnum_tostr(rev1, rbuf1, sizeof(rbuf1));
        if (!quiet)
                fprintf(stderr, "retrieving revision %s\n", rbuf1);

        if ((b1 = rcs_getrev(file, rev1)) == NULL) {
                warnx("failed to retrieve revision %s", rbuf1);
                goto out;
        }

        b1 = rcs_kwexp_buf(b1, file, rev1);
        tv[0].tv_sec = rcs_rev_getdate(file, rev1);
        tv[1].tv_sec = tv[0].tv_sec;

        rcsnum_tostr(rev2, rbuf2, sizeof(rbuf2));
        if (!quiet)
                fprintf(stderr, "retrieving revision %s\n", rbuf2);

        if ((b2 = rcs_getrev(file, rev2)) == NULL) {
                warnx("failed to retrieve revision %s", rbuf2);
                goto out;
        }

        b2 = rcs_kwexp_buf(b2, file, rev2);
        tv2[0].tv_sec = rcs_rev_getdate(file, rev2);
        tv2[1].tv_sec = tv2[0].tv_sec;

        if (!quiet)
                fprintf(stderr, "%s -r%s -r%s\n", diffargs, rbuf1, rbuf2);

        (void)xasprintf(&path1, "%s/diff1.XXXXXXXXXX", rcs_tmpdir);
        buf_write_stmp(b1, path1);

        buf_free(b1);
        b1 = NULL;

        if (utimes(path1, (const struct timeval *)&tv) == -1)
                warn("utimes");

        (void)xasprintf(&path2, "%s/diff2.XXXXXXXXXX", rcs_tmpdir);
        buf_write_stmp(b2, path2);

        buf_free(b2);
        b2 = NULL;

        if (utimes(path2, (const struct timeval *)&tv2) == -1)
                warn("utimes");

        ret = diffreg(path1, path2, NULL, dflags);

out:
        buf_free(b1);
        buf_free(b2);
        free(path1);
        free(path2);

        return (ret);
}

static void
push_ignore_pats(char *pattern)
{
        size_t len;

        if (diff_ignore_pats == NULL) {
                len = strlen(pattern) + 1;
                diff_ignore_pats = xmalloc(len);
                strlcpy(diff_ignore_pats, pattern, len);
        } else {
                /* old + "|" + new + NUL */
                len = strlen(diff_ignore_pats) + strlen(pattern) + 2;
                diff_ignore_pats = xreallocarray(diff_ignore_pats, len, 1);
                strlcat(diff_ignore_pats, "|", len);
                strlcat(diff_ignore_pats, pattern, len);
        }
}