/*
 * Copyright 2000 Massachusetts Institute of Technology
 *
 * Permission to use, copy, modify, and distribute this software and
 * its documentation for any purpose and without fee is hereby
 * granted, provided that both the above copyright notice and this
 * permission notice appear in all copies, that both the above
 * copyright notice and this permission notice appear in all
 * supporting documentation, and that the name of M.I.T. not be used
 * in advertising or publicity pertaining to distribution of the
 * software without specific, written prior permission.  M.I.T. makes
 * no representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied
 * warranty.
 *
 * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''.  M.I.T. DISCLAIMS
 * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
 * SHALL M.I.T. 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 <err.h>
#include <errno.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <sysexits.h>
#include <unistd.h>

#include "getconf.h"

static void     do_allsys(void);
static void     do_allpath(const char *path);
static void     do_confstr(const char *name, int key);
static void     do_sysconf(const char *name, int key);
static void     do_pathconf(const char *name, int key, const char *path);

static void
usage(void)
{
        fprintf(stderr,
"usage: getconf -a [pathname]\n"
"       getconf [-v prog_env] system_var\n"
"       getconf [-v prog_env] path_var pathname\n");
        exit(EX_USAGE);
}

int
main(int argc, char **argv)
{
        bool aflag;
        int c, key, valid;
        const char *name, *vflag, *alt_path;
        intmax_t limitval;
        uintmax_t ulimitval;

        aflag = false;
        vflag = NULL;
        while ((c = getopt(argc, argv, "av:")) != -1) {
                switch (c) {
                case 'a':
                        aflag = true;
                        break;
                case 'v':
                        vflag = optarg;
                        break;

                default:
                        usage();
                }
        }

        if (aflag) {
                if (vflag != NULL)
                        usage();
                if (argv[optind] == NULL)
                        do_allsys();
                else
                        do_allpath(argv[optind]);
                return (0);
        }

        if ((name = argv[optind]) == NULL)
                usage();

        if (vflag != NULL) {
                if ((valid = find_progenv(vflag, &alt_path)) == 0)
                        errx(EX_USAGE, "invalid programming environment %s",
                             vflag);
                if (valid > 0 && alt_path != NULL) {
                        if (argv[optind + 1] == NULL)
                                execl(alt_path, "getconf", argv[optind],
                                      (char *)NULL);
                        else
                                execl(alt_path, "getconf", argv[optind],
                                      argv[optind + 1], (char *)NULL);

                        err(EX_OSERR, "execl: %s", alt_path);
                }
                if (valid < 0)
                        errx(EX_UNAVAILABLE, "environment %s is not available",
                             vflag);
        }

        if (argv[optind + 1] == NULL) { /* confstr or sysconf */
                if ((valid = find_unsigned_limit(name, &ulimitval)) != 0) {
                        if (valid > 0)
                                printf("%" PRIuMAX "\n", ulimitval);
                        else
                                printf("undefined\n");
                        return 0;
                }
                if ((valid = find_limit(name, &limitval)) != 0) {
                        if (valid > 0)
                                printf("%" PRIdMAX "\n", limitval);
                        else
                                printf("undefined\n");

                        return 0;
                }
                if ((valid = find_confstr(name, &key)) != 0) {
                        if (valid > 0)
                                do_confstr(name, key);
                        else
                                printf("undefined\n");
                } else {
                        valid = find_sysconf(name, &key);
                        if (valid > 0) {
                                do_sysconf(name, key);
                        } else if (valid < 0) {
                                printf("undefined\n");
                        } else
                                errx(EX_USAGE,
                                     "no such configuration parameter `%s'",
                                     name);
                }
        } else {
                valid = find_pathconf(name, &key);
                if (valid != 0) {
                        if (valid > 0)
                                do_pathconf(name, key, argv[optind + 1]);
                        else
                                printf("undefined\n");
                } else
                        errx(EX_USAGE,
                             "no such path configuration parameter `%s'",
                             name);
        }
        return 0;
}

static void
do_onestr(const char *name, int key)
{
        size_t len;

        errno = 0;
        len = confstr(key, 0, 0);
        if (len == 0 && errno != 0) {
                warn("confstr: %s", name);
                return;
        }
        printf("%s: ", name);
        if (len == 0)
                printf("undefined\n");
        else {
                char buf[len + 1];

                confstr(key, buf, len);
                printf("%s\n", buf);
        }
}

static void
do_onesys(const char *name, int key)
{
        long value;

        errno = 0;
        value = sysconf(key);
        if (value == -1 && errno != 0) {
                warn("sysconf: %s", name);
                return;
        }
        printf("%s: ", name);
        if (value == -1)
                printf("undefined\n");
        else
                printf("%ld\n", value);
}

static void
do_allsys(void)
{

        foreach_confstr(do_onestr);
        foreach_sysconf(do_onesys);
}

static void
do_onepath(const char *name, int key, const char *path)
{
        long value;

        errno = 0;
        value = pathconf(path, key);
        if (value == -1 && errno != EINVAL && errno != 0)
                warn("pathconf: %s", name);
        printf("%s: ", name);
        if (value == -1)
                printf("undefined\n");
        else
                printf("%ld\n", value);
}

static void
do_allpath(const char *path)
{

        foreach_pathconf(do_onepath, path);
}

static void
do_confstr(const char *name, int key)
{
        size_t len;
        int savederr;

        savederr = errno;
        errno = 0;
        len = confstr(key, 0, 0);
        if (len == 0) {
                if (errno)
                        err(EX_OSERR, "confstr: %s", name);
                else
                        printf("undefined\n");
        } else {
                char buf[len + 1];

                confstr(key, buf, len);
                printf("%s\n", buf);
        }
        errno = savederr;
}

static void
do_sysconf(const char *name, int key)
{
        long value;

        errno = 0;
        value = sysconf(key);
        if (value == -1 && errno != 0)
                err(EX_OSERR, "sysconf: %s", name);
        else if (value == -1)
                printf("undefined\n");
        else
                printf("%ld\n", value);
}

static void
do_pathconf(const char *name, int key, const char *path)
{
        long value;

        errno = 0;
        value = pathconf(path, key);
        if (value == -1 && errno != 0)
                err(EX_OSERR, "pathconf: %s", name);
        else if (value == -1)
                printf("undefined\n");
        else
                printf("%ld\n", value);
}