/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2000 Sheldon Hearn <sheldonh@FreeBSD.org>.
 * All rights reserved.
 *
 * Copyright (c) 2021 The FreeBSD Foundation
 *
 * Portions of this software were developed by Ka Ho Ng <khng@FreeBSD.org>
 * under sponsorship from the FreeBSD Foundation.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
 *
 */

#include <sys/stat.h>

#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#include <libutil.h>

static void     usage(void);

int
main(int argc, char **argv)
{
        struct stat sb;
        mode_t omode;
        off_t oflow, rsize, sz, tsize, round, off, len;
        uint64_t usz;
        int ch, error, fd, oflags, r;
        int do_dealloc;
        int do_truncate;
        int no_create;
        int do_relative;
        int do_round;
        int do_refer;
        int got_size;
        char *fname, *rname;

        fd = -1;
        rsize = tsize = sz = off = 0;
        len = -1;
        do_dealloc = no_create = do_relative = do_round = do_refer =
            got_size = 0;
        do_truncate = 1;
        error = r = 0;
        rname = NULL;
        while ((ch = getopt(argc, argv, "cdr:s:o:l:")) != -1)
                switch (ch) {
                case 'c':
                        no_create = 1;
                        break;
                case 'd':
                        do_dealloc = 1;
                        do_truncate = 0;
                        break;
                case 'r':
                        do_refer = 1;
                        rname = optarg;
                        break;
                case 's':
                        if (*optarg == '+' || *optarg == '-') {
                                do_relative = 1;
                        } else if (*optarg == '%' || *optarg == '/') {
                                do_round = 1;
                        }
                        if (expand_number(do_relative || do_round ?
                            optarg + 1 : optarg,
                            &usz) == -1 || (off_t)usz < 0)
                                errx(EXIT_FAILURE,
                                    "invalid size argument `%s'", optarg);

                        sz = (*optarg == '-' || *optarg == '/') ?
                                -(off_t)usz : (off_t)usz;
                        got_size = 1;
                        break;
                case 'o':
                        if (expand_number(optarg, &usz) == -1 ||
                            (off_t)usz < 0)
                                errx(EXIT_FAILURE,
                                    "invalid offset argument `%s'", optarg);

                        off = usz;
                        break;
                case 'l':
                        if (expand_number(optarg, &usz) == -1 ||
                            (off_t)usz <= 0)
                                errx(EXIT_FAILURE,
                                    "invalid length argument `%s'", optarg);

                        len = usz;
                        break;
                default:
                        usage();
                        /* NOTREACHED */
                }

        argv += optind;
        argc -= optind;

        /*
         * Exactly one of do_refer, got_size or do_dealloc must be specified.
         * Since do_relative implies got_size, do_relative, do_refer and
         * do_dealloc are also mutually exclusive.  If do_dealloc is specified,
         * the length argument must be set.  See usage() for allowed
         * invocations.
         */
        if (argc < 1 || do_refer + got_size + do_dealloc != 1 ||
            (do_dealloc == 1 && len == -1))
                usage();
        if (do_refer == 1) {
                if (stat(rname, &sb) == -1)
                        err(EXIT_FAILURE, "%s", rname);
                tsize = sb.st_size;
        } else if (do_relative == 1 || do_round == 1)
                rsize = sz;
        else if (do_dealloc == 0)
                tsize = sz;

        if (no_create)
                oflags = O_WRONLY;
        else
                oflags = O_WRONLY | O_CREAT;
        omode = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH;

        while ((fname = *argv++) != NULL) {
                if (fd != -1)
                        close(fd);
                if ((fd = open(fname, oflags, omode)) == -1) {
                        if (errno != ENOENT) {
                                warn("%s", fname);
                                error++;
                        }
                        continue;
                }
                if (do_relative == 1) {
                        if (fstat(fd, &sb) == -1) {
                                warn("%s", fname);
                                error++;
                                continue;
                        }
                        oflow = sb.st_size + rsize;
                        if (oflow < (sb.st_size + rsize)) {
                                errno = EFBIG;
                                warn("%s", fname);
                                error++;
                                continue;
                        }
                        tsize = oflow;
                }
                if (do_round == 1) {
                        if (fstat(fd, &sb) == -1) {
                                warn("%s", fname);
                                error++;
                                continue;
                        }
                        sz = rsize;
                        if (sz < 0)
                                sz = -sz;
                        if (sb.st_size % sz) {
                                round = sb.st_size / sz;
                                if (round != sz && rsize < 0)
                                        round--;
                                else if (rsize > 0)
                                        round++;
                                tsize = (round < 0 ? 0 : round) * sz;
                        } else
                                tsize = sb.st_size;
                }
                if (tsize < 0)
                        tsize = 0;

                if (do_dealloc == 1) {
                        struct spacectl_range sr;

                        sr.r_offset = off;
                        sr.r_len = len;
                        r = fspacectl(fd, SPACECTL_DEALLOC, &sr, 0, &sr);
                }
                if (do_truncate == 1)
                        r = ftruncate(fd, tsize);
                if (r == -1) {
                        warn("%s", fname);
                        error++;
                }
        }
        if (fd != -1)
                close(fd);

        return (error ? EXIT_FAILURE : EXIT_SUCCESS);
}

static void
usage(void)
{
        fprintf(stderr, "%s\n%s\n%s\n",
            "usage: truncate [-c] -s [+|-|%|/]size[K|k|M|m|G|g|T|t] file ...",
            "       truncate [-c] -r rfile file ...",
            "       truncate [-c] -d [-o offset[K|k|M|m|G|g|T|t]] -l length[K|k|M|m|G|g|T|t] file ...");
        exit(EXIT_FAILURE);
}