/*      $OpenBSD: dc.c,v 1.21 2024/04/23 13:34:50 jsg Exp $     */

/*
 * Copyright (c) 2003, Otto Moerbeek <otto@drijf.net>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/stat.h>
#include <err.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "extern.h"

static __dead void      usage(void);

extern char             *__progname;

static __dead void
usage(void)
{
        (void)fprintf(stderr, "usage: %s [-x] [-e expression] [file]\n",
            __progname);
        exit(1);
}

int
dc_main(int argc, char *argv[])
{
        int             ch;
        bool            extended_regs = false;
        FILE            *file;
        struct source   src;
        char            *buf, *p;
        struct stat     st;

        buf = bstrdup("");
        /* accept and ignore a single dash to be 4.4BSD dc(1) compatible */
        optind = 1;
        optreset = 1;
        while ((ch = getopt(argc, argv, "e:x-")) != -1) {
                switch (ch) {
                case 'e':
                        p = buf;
                        if (asprintf(&buf, "%s %s", buf, optarg) == -1)
                                err(1, NULL);
                        free(p);
                        break;
                case 'x':
                        extended_regs = true;
                        break;
                case '-':
                        break;
                default:
                        usage();
                }
        }
        argc -= optind;
        argv += optind;

        if (argc == 0) {
                if (pledge("stdio", NULL) == -1)
                        err(1, "pledge");
        }

        init_bmachine(extended_regs);
        (void)setvbuf(stdout, NULL, _IOLBF, 0);
        (void)setvbuf(stderr, NULL, _IOLBF, 0);

        if (argc > 1)
                usage();
        if (buf[0] != '\0') {
                src_setstring(&src, buf);
                reset_bmachine(&src);
                eval();
                free(buf);
                if (argc == 0)
                        return (0);
        }
        if (argc == 1) {
                file = fopen(argv[0], "r");
                if (file == NULL)
                        err(1, "cannot open file %s", argv[0]);

                if (pledge("stdio", NULL) == -1)
                        err(1, "pledge");

                if (fstat(fileno(file), &st) == -1)
                        err(1, "%s", argv[0]);
                if (S_ISDIR(st.st_mode))
                        errc(1, EISDIR, "%s", argv[0]);
                src_setstream(&src, file);
                reset_bmachine(&src);
                eval();
                (void)fclose(file);
                /*
                 * BSD and Solaris dc(1) continue with stdin after processing
                 * the file given as the argument. We follow GNU dc(1).
                 */
                return (0);
        }

        src_setstream(&src, stdin);
        reset_bmachine(&src);
        eval();

        return (0);
}