/*
 * Copyright (c) 2003 Matthew Dillon <dillon@backplane.com>
 * 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.
 *
 * $DragonFly: src/bin/varsym/varsym.c,v 1.4 2003/12/11 20:33:49 dillon Exp $
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <sys/varsym.h>

static void dumpvars(char *buf, int bytes);
static int doexec(char **av);
static void usage(void);

int
main(int ac, char **av)
{
        int i;
        int mask =  VARSYM_ALL_MASK;
        int level = VARSYM_USER;
        int deleteOpt = 0;
        int verboseOpt = 1;
        int allOpt = 0;
        int execok = 0;
        int ret = 0;

        while ((i = getopt(ac, av, "adhpqsux")) != -1) {
                switch (i) {
                case 'a':
                        allOpt = 1;
                        break;
                case 'd':
                        deleteOpt = 1;
                        break;
                case 'p':
                        mask = VARSYM_PROC_MASK;
                        level = VARSYM_PROC;
                        break;
                case 'q':
                        verboseOpt = 0;
                        break;
                case 's':
                        mask = VARSYM_SYS_MASK;
                        level = VARSYM_SYS;
                        break;
                case 'u':
                        mask = VARSYM_USER_MASK;
                        level = VARSYM_USER;
                        break;
                case 'x':
                        mask = VARSYM_PROC_MASK;
                        level = VARSYM_PROC;
                        execok = 1;
                        break;
                case 'h':
                default:
                        usage();
                        return(-1);
                }
        }

        if (allOpt) {
                char buf[1024];
                int marker = 0;
                int bytes;

                for (;;) {
                        bytes = varsym_list(level, buf, sizeof(buf), &marker);
                        if (bytes < 0)          /* error occured */
                            break;
                        dumpvars(buf, bytes);
                        if (marker < 0)         /* no more vars */
                            break;
                }
                if (bytes < 0) {
                        fprintf(stderr, "varsym_list(): %s\n", strerror(errno));
                        return 1;
                }
        }

        for ( ; optind < ac; optind++) {
                char *name = av[optind];
                char *data = strchr(name, '=');
                int error;
                char buf[MAXVARSYM_DATA];

                if (data)
                        *data++ = 0;

                if (execok) {
                        if (deleteOpt) {
                                usage();
                                exit(1);
                        }
                        if (data) {
                                error = varsym_set(level, name, data);
                                if (error)
                                        ret = 2;
                        } else {
                                error = doexec(av + optind);
                        }
                } else if (deleteOpt) {
                        error = varsym_set(level, name, NULL);
                        if (error)
                                ret = 2;
                } else if (data) {
                        error = varsym_set(level, name, data);
                        if (error)
                                ret = 2;
                } else {
                        /*
                         * NOTE: System call returns 0 on success now,
                         *       but older versions returns the content
                         *       strlen() + 1, and that had to be tested
                         *       for overflow conditions.
                         */
                        error = varsym_get(mask, name, buf, sizeof(buf));
                        if (error >= 0 && error <= (int)sizeof(buf)) {
                                if (verboseOpt)
                                        printf("%s=", name);
                                printf("%s\n", buf);
                        } else {
                                ret = 1;
                        }
                }
                if (error < 0 && verboseOpt)
                        fprintf(stderr, "%s: %s\n", name, strerror(errno));
        }

        return ret;
}

static void
dumpvars(char *buf, int bytes)
{
        int b;
        int i;
        char *vname = NULL;
        char *vdata = NULL;

        for (b = i = 0; i < bytes; ++i) {
                if (buf[i] == 0) {
                        if (vname == NULL) {
                                vname = buf + b;
                        } else {
                                vdata = buf + b;
                                printf("%s=%s\n", vname, vdata);
                                vname = vdata = NULL;
                        }
                        b = i + 1;
                }
        }
}

static int
doexec(char **av)
{
        int error;

        error = execvp(av[0], av);
        return (error);
}

static void
usage(void)
{
        fprintf(stderr, "usage: varsym [-adpqsu] [var[=data] ...]\n");
}