/* $NetBSD: iconv.c,v 1.16 2009/02/20 15:28:21 yamt Exp $ */

/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c)2003 Citrus Project,
 * 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.
 *
 * 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/capsicum.h>

#include <capsicum_helpers.h>
#include <err.h>
#include <errno.h>
#include <getopt.h>
#include <iconv.h>
#include <limits.h>
#include <locale.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

static int              do_conv(FILE *, iconv_t, bool, bool);
static int              do_list(unsigned int, const char * const *, void *);
static void             usage(void) __dead2;

static const struct option long_options[] = {
        {"from-code",           required_argument,      NULL, 'f'},
        {"list",                no_argument,            NULL, 'l'},
        {"silent",              no_argument,            NULL, 's'},
        {"to-code",             required_argument,      NULL, 't'},
        {NULL,                  no_argument,            NULL, 0}
};

static void
usage(void)
{
        (void)fprintf(stderr,
            "Usage:\t%1$s [-cs] -f <from_code> -t <to_code> [file ...]\n"
            "\t%1$s -f <from_code> [-cs] [-t <to_code>] [file ...]\n"
            "\t%1$s -t <to_code> [-cs] [-f <from_code>] [file ...]\n"
            "\t%1$s -l\n", getprogname());
        exit(1);
}

#define INBUFSIZE 1024
#define OUTBUFSIZE (INBUFSIZE * 2)
static int
do_conv(FILE *fp, iconv_t cd, bool silent, bool hide_invalid)
{
        char inbuf[INBUFSIZE], outbuf[OUTBUFSIZE], *in, *out;
        unsigned long long invalids;
        size_t inbytes, outbytes, ret;

        /*
         * Don't touch ICONV_SET_DISCARD_ILSEQ if -c wasn't specified.  It may
         * be that the user has specified //IGNORE in the -t specification, and
         * we don't want to clobber that.
         */
        if (hide_invalid) {
                int arg = (int)hide_invalid;
                if (iconvctl(cd, ICONV_SET_DISCARD_ILSEQ, (void *)&arg) == -1)
                        err(EXIT_FAILURE, "iconvctl(DISCARD_ILSEQ, %d)", arg);
        }

        invalids = 0;
        while ((inbytes = fread(inbuf, 1, INBUFSIZE, fp)) > 0) {
                in = inbuf;
                while (inbytes > 0) {
                        size_t inval;

                        out = outbuf;
                        outbytes = OUTBUFSIZE;
                        ret = __iconv(cd, &in, &inbytes, &out, &outbytes,
                            0, &inval);
                        invalids += inval;
                        if (outbytes < OUTBUFSIZE)
                                (void)fwrite(outbuf, 1, OUTBUFSIZE - outbytes,
                                    stdout);
                        if (ret == (size_t)-1 && errno != E2BIG) {
                                if (errno != EINVAL || in == inbuf)
                                        err(EXIT_FAILURE, "iconv()");

                                /* incomplete input character */
                                (void)memmove(inbuf, in, inbytes);
                                ret = fread(inbuf + inbytes, 1,
                                    INBUFSIZE - inbytes, fp);
                                if (ret == 0) {
                                        fflush(stdout);
                                        if (feof(fp))
                                                errx(EXIT_FAILURE,
                                                    "unexpected end of file; "
                                                    "the last character is "
                                                    "incomplete.");
                                        else
                                                err(EXIT_FAILURE, "fread()");
                                }
                                in = inbuf;
                                inbytes += ret;
                        }
                }
        }
        /* reset the shift state of the output buffer */
        outbytes = OUTBUFSIZE;
        out = outbuf;
        ret = iconv(cd, NULL, NULL, &out, &outbytes);
        if (ret == (size_t)-1)
                err(EXIT_FAILURE, "iconv()");
        if (outbytes < OUTBUFSIZE)
                (void)fwrite(outbuf, 1, OUTBUFSIZE - outbytes, stdout);

        if (invalids > 0 && !silent)
                warnx("warning: invalid characters: %llu", invalids);

        return (invalids > 0);
}

static int
do_list(unsigned int n, const char * const *list, void *data __unused)
{
        unsigned int i;

        for(i = 0; i < n; i++) {
                printf("%s", list[i]);
                if (i < n - 1)
                        printf(" ");
        }
        printf("\n");

        return (1);
}

int
main(int argc, char **argv)
{
        iconv_t cd;
        FILE *fp;
        const char *opt_f, *opt_t;
        int ch, i, res;
        bool opt_c = false, opt_s = false;

        opt_f = opt_t = "";

        setlocale(LC_ALL, "");
        setprogname(argv[0]);

        while ((ch = getopt_long(argc, argv, "csLlf:t:",
            long_options, NULL)) != -1) {
                switch (ch) {
                case 'c':
                        opt_c = true;
                        break;
                case 's':
                        opt_s = true;
                        break;
                case 'l':
                        /* list */
                        if (opt_s || opt_c || strcmp(opt_f, "") != 0 ||
                            strcmp(opt_t, "") != 0) {
                                warnx("-l is not allowed with other flags.");
                                usage();
                        }
                        iconvlist(do_list, NULL);
                        return (EXIT_SUCCESS);
                case 'f':
                        /* from */
                        if (optarg != NULL)
                                opt_f = optarg;
                        break;
                case 't':
                        /* to */
                        if (optarg != NULL)
                                opt_t = optarg;
                        break;
                default:
                        usage();
                }
        }
        argc -= optind;
        argv += optind;
        if ((strcmp(opt_f, "") == 0) && (strcmp(opt_t, "") == 0))
                usage();

        if (caph_limit_stdio() < 0)
                err(EXIT_FAILURE, "capsicum");

        /*
         * Cache NLS data, for strerror, for err(3), before entering capability
         * mode.
         */
        caph_cache_catpages();

        /*
         * Cache iconv conversion handle before entering sandbox.
         */
        cd = iconv_open(opt_t, opt_f);
        if (cd == (iconv_t)-1)
                err(EXIT_FAILURE, "iconv_open(%s, %s)", opt_t, opt_f);

        if (argc == 0) {
                if (caph_enter() < 0)
                        err(EXIT_FAILURE, "unable to enter capability mode");
                res = do_conv(stdin, cd, opt_s, opt_c);
        } else {
                res = 0;
                for (i = 0; i < argc; i++) {
                        fp = (strcmp(argv[i], "-") != 0) ?
                            fopen(argv[i], "r") : stdin;
                        if (fp == NULL)
                                err(EXIT_FAILURE, "Cannot open `%s'",
                                    argv[i]);
                        /* Enter Capsicum sandbox for final input file. */
                        if (i + 1 == argc && caph_enter() < 0)
                                err(EXIT_FAILURE,
                                    "unable to enter capability mode");
                        res |= do_conv(fp, cd, opt_s, opt_c);
                        (void)fclose(fp);

                        /* Reset iconv descriptor state. */
                        (void)iconv(cd, NULL, NULL, NULL, NULL);
                }
        }
        iconv_close(cd);
        return (res == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
}