/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2000  Peter Wemm <peter@freebsd.org>
 *
 * 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 AUTHORS 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 AUTHORS 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/types.h>
#include <sys/sysctl.h>
#include <err.h>
#include <errno.h>
#include <kenv.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

static void     usage(void);
static int      kdumpenv(int dump_type);
static int      kgetenv(const char *);
static int      ksetenv(const char *, char *);
static int      kunsetenv(const char *);

static int hflag = 0;
static int lflag = 0;
static int Nflag = 0;
static int qflag = 0;
static int sflag = 0;
static int uflag = 0;
static int vflag = 0;

static void
usage(void)
{
        (void)fprintf(stderr, "%s\n%s\n%s\n",
            "usage: kenv [-l|-s] [-hNq]",
            "       kenv [-qv] variable[=value]",
            "       kenv [-q] -u variable");
        exit(1);
}

int
main(int argc, char **argv)
{
        char *env, *eq, *val;
        int ch, error;

        val = NULL;
        env = NULL;
        while ((ch = getopt(argc, argv, "hlNqsuv")) != -1) {
                switch (ch) {
                case 'h':
                        hflag++;
                        break;
                case 'l':
                        lflag++;
                        break;
                case 'N':
                        Nflag++;
                        break;
                case 'q':
                        qflag++;
                        break;
                case 's':
                        sflag++;
                        break;
                case 'u':
                        uflag++;
                        break;
                case 'v':
                        vflag++;
                        break;
                default:
                        usage();
                }
        }
        argc -= optind;
        argv += optind;
        if (argc > 0) {
                env = argv[0];
                eq = strchr(env, '=');
                if (eq != NULL) {
                        *eq++ = '\0';
                        val = eq;
                }
                argv++;
                argc--;
        }
        if ((hflag || Nflag) && env != NULL)
                usage();
        if (lflag && sflag)
                usage();
        if (argc > 0 || ((uflag || vflag) && env == NULL))
                usage();
        if (env == NULL) {
                if (lflag)
                        error = kdumpenv(KENV_DUMP_LOADER);
                else if (sflag)
                        error = kdumpenv(KENV_DUMP_STATIC);
                else
                        error = kdumpenv(KENV_DUMP);
                if (error && !qflag) {
                        if (errno == ENOENT)
                                warnx("requested environment is unavailable");
                        else
                                warn("kdumpenv");
                }
        } else if (val == NULL) {
                if (uflag) {
                        error = kunsetenv(env);
                        if (error && !qflag)
                                warnx("unable to unset %s", env);
                } else {
                        error = kgetenv(env);
                        if (error && !qflag)
                                warnx("unable to get %s", env);
                }
        } else {
                error = ksetenv(env, val);
                if (error && !qflag)
                        warnx("unable to set %s to %s", env, val);
        }
        return (error);
}

static int
kdumpenv(int dump_type)
{
        char *buf, *bp, *cp;
        int buflen, envlen;

        envlen = kenv(dump_type, NULL, NULL, 0);
        if (envlen < 0)
                return (-1);
        for (;;) {
                buflen = envlen * 120 / 100;
                buf = calloc(1, buflen + 1);
                if (buf == NULL)
                        return (-1);
                envlen = kenv(dump_type, NULL, buf, buflen);
                if (envlen < 0) {
                        free(buf);
                        return (-1);
                }
                if (envlen > buflen)
                        free(buf);
                else
                        break;
        }

        for (bp = buf; *bp != '\0'; bp += strlen(bp) + 1) {
                if (hflag) {
                        if (strncmp(bp, "hint.", 5) != 0)
                                continue;
                }
                cp = strchr(bp, '=');
                if (cp == NULL)
                        continue;
                *cp++ = '\0';
                if (Nflag)
                        printf("%s\n", bp);
                else
                        printf("%s=\"%s\"\n", bp, cp);
                bp = cp;
        }

        free(buf);
        return (0);
}

static int
kgetenv(const char *env)
{
        char buf[1024];
        int ret;

        ret = kenv(KENV_GET, env, buf, sizeof(buf));
        if (ret == -1)
                return (ret);
        if (vflag)
                printf("%s=\"%s\"\n", env, buf);
        else
                printf("%s\n", buf);
        return (0);
}

static int
ksetenv(const char *env, char *val)
{
        int ret;

        ret = kenv(KENV_SET, env, val, strlen(val) + 1);
        if (ret == 0)
                printf("%s=\"%s\"\n", env, val);
        return (ret);
}

static int
kunsetenv(const char *env)
{
        int ret;

        ret = kenv(KENV_UNSET, env, NULL, 0);
        return (ret);
}