Colony » Colony Scout

/*

 * Copyright (c) 2009, Kohsuke Ohtani

 * 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.

 * 3. Neither the name of the author nor the names of any co-contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific prior written permission.

 *

 * 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 <unistd.h>

#include <stdlib.h>

#include <string.h>

#include <stdio.h>

#include <errno.h>

extern char **environ;

/*

 * Shell variables.

 */

#define VTABSIZE        20

#define MAXVARNAME        32

struct var {

        char        *name;

        char        *val;

};

static struct var vartab[VTABSIZE];

static int

is_name(char c)

{

        if ((c >= 'a' && c <= 'z') ||

            (c >= 'A' && c <= 'Z') || c == '_')

                return 1;

        return 0;

}

static int

is_validname(char *name)

{

        char *p;

        for (p = name; *p != '\0'; p++) {

                if (!is_name(*p))

                        return 0;

        }

        return 1;

}

static struct var *

lookupvar(char *name)

{

        struct var *var;

        int i;

        var = &vartab[0];

        for (i = 0; i < VTABSIZE; i++) {

                if (var->name != NULL && !strcmp(var->name, name))

                        return var;

                var++;

        }

        return NULL;

}

void

setvar(char *name, char *val)

{

        struct var *var, *free;

        int i;

        /*

         * Lookup existing name in variable table.

         */

        var = lookupvar(name);

        if (var == NULL) {

                /*

                 * Not found. Find empty slot.

                 */

                free = NULL;

                var = &vartab[0];

                for (i = 0; i < VTABSIZE; i++) {

                        if (var->name == NULL) {

                                free = var;

                                break;

                        }

                        var++;

                }

                if (free == NULL) {

                        fprintf(stderr, "too many variables\n");

                        return;

                }

                var = free;

        }

        if (!is_validname(name)) {

                fprintf(stderr, "%s: bad vairable name\n", name);

                return;

        }

        if ((var->name = strdup(name)) == NULL) {

                fprintf(stderr, "out of memory\n");

                return;

        }

        var->val = strdup(val);

}

void

unsetvar(char *name)

{

        struct var *var;

        /* Find target slot in variable table */

        var = lookupvar(name);

        if (var == NULL)

                return;

        free(var->name);

        free(var->val);

        var->name = NULL;

        var->val = NULL;

}

void

setvareq(char *str)

{

        char name[MAXVARNAME];

        char *p, *s;

        int i;

        s = str;

        p = name;

        for (i = 0; i < MAXVARNAME - 1; i++) {

                *p++ = *s++;

                if (*s == '=')

                        break;

        }

        *p = '\0';

        p = strchr(str, '=');

        setvar(name, p + 1);

}

int

cmd_showvars(int argc, char *argv[])

{

        struct var *var;

        int i;

        var = &vartab[0];

        for (i = 0; i < VTABSIZE; i++) {

                if (var->name != NULL)

                        printf("%s=%s\n", var->name, var->val);

                var++;

        }

        return 0;

}

int

cmd_unsetvar(int argc, char *argv[])

{

        if (argc != 2) {

                fprintf(stderr, "usage: unset name\n");

                return 0;

        }

        unsetvar(argv[1]);

        return 0;

}

int

cmd_export(int argc, char *argv[])

{

        struct var *var;

        int i;

        if (argc == 1) {

                fprintf(stderr, "usage: export name\n");

                return 0;

        }

        for (i = 1; i < argc; i++) {

                var = lookupvar(argv[i]);

                if (var != NULL)

                        setenv(var->name, var->val, 1);

        }

        return 0;

}

void

initvar(void)

{

        char **envp;

        int i;

        for (i = 0; i < VTABSIZE; i++)

                vartab[i].name = NULL;

        for (envp = environ; *envp; envp++) {

                if (strchr(*envp, '='))

                        setvareq(*envp);

        }

}