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/*  $NetBSD: alias.c,v 1.10 1998/05/20 00:27:56 christos Exp $  */

/*-

 * Copyright (c) 1993

 *  The Regents of the University of California.  All rights reserved.

 *

 * This code is derived from software contributed to Berkeley by

 * Kenneth Almquist.

 *

 * 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. All advertising materials mentioning features or use of this software

 *    must display the following acknowledgement:

 *  This product includes software developed by the University of

 *  California, Berkeley and its contributors.

 * 4. Neither the name of the University nor the names of its contributors

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

 *    without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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/cdefs.h>

#ifndef lint

#if 0

static char sccsid[] = "@(#)alias.c 8.3 (Berkeley) 5/4/95";

#else

__RCSID("$NetBSD: alias.c,v 1.10 1998/05/20 00:27:56 christos Exp $");

#endif

#endif /* not lint */

#include <stdlib.h>

#include "shell.h"

#include "input.h"

#include "output.h"

#include "error.h"

#include "memalloc.h"

#include "mystring.h"

#include "alias.h"

#include "options.h"    /* XXX for argptr (should remove?) */

#define ATABSIZE 39

struct alias *atab[ATABSIZE];

STATIC void setalias (char *, char *);

STATIC int unalias (char *);

STATIC struct alias **hashalias (char *);

STATIC

void

setalias(char *name, char *val)

{

    struct alias *ap, **app;

    app = hashalias(name);

    for (ap = *app; ap; ap = ap->next) {

        if (equal(name, ap->name)) {

            INTOFF;

            ckfree(ap->val);

            ap->val = savestr(val);

            INTON;

            return;

        }

    }

    /* not found */

    INTOFF;

    ap = ckmalloc(sizeof (struct alias));

    ap->name = savestr(name);

    /*

     * XXX - HACK: in order that the parser will not finish reading the

     * alias value off the input before processing the next alias, we

     * dummy up an extra space at the end of the alias.  This is a crock

     * and should be re-thought.  The idea (if you feel inclined to help)

     * is to avoid alias recursions.  The mechanism used is: when

     * expanding an alias, the value of the alias is pushed back on the

     * input as a string and a pointer to the alias is stored with the

     * string.  The alias is marked as being in use.  When the input

     * routine finishes reading the string, it markes the alias not

     * in use.  The problem is synchronization with the parser.  Since

     * it reads ahead, the alias is marked not in use before the

     * resulting token(s) is next checked for further alias sub.  The

     * H A C K is that we add a little fluff after the alias value

     * so that the string will not be exhausted.  This is a good

     * idea ------- ***NOT***

     */

#ifdef notyet

    ap->val = savestr(val);

#else /* hack */

    {

    int len = strlen(val);

    ap->val = ckmalloc(len + 2);

    memcpy(ap->val, val, len);

    ap->val[len] = ' '; /* fluff */

    ap->val[len+1] = '\0';

    }

#endif

    ap->next = *app;

    *app = ap;

    INTON;

}

STATIC int

unalias(name)

    char *name;

    {

    struct alias *ap, **app;

    app = hashalias(name);

    for (ap = *app; ap; app = &(ap->next), ap = ap->next) {

        if (equal(name, ap->name)) {

            /*

             * if the alias is currently in use (i.e. its

             * buffer is being used by the input routine) we

             * just null out the name instead of freeing it.

             * We could clear it out later, but this situation

             * is so rare that it hardly seems worth it.

             */

            if (ap->flag & ALIASINUSE)

                *ap->name = '\0';

            else {

                INTOFF;

                *app = ap->next;

                ckfree(ap->name);

                ckfree(ap->val);

                ckfree(ap);

                INTON;

            }

            return (0);

        }

    }

    return (1);

}

#ifdef mkinit

MKINIT void rmaliases (void);

SHELLPROC {

    rmaliases();

}

#endif

void

rmaliases() {

    struct alias *ap, *tmp;

    int i;

    INTOFF;

    for (i = 0; i < ATABSIZE; i++) {

        ap = atab[i];

        atab[i] = NULL;

        while (ap) {

            ckfree(ap->name);

            ckfree(ap->val);

            tmp = ap;

            ap = ap->next;

            ckfree(tmp);

        }

    }

    INTON;

}

struct alias *

lookupalias(name, check)

    char *name;

    int check;

{

    struct alias *ap = *hashalias(name);

    for (; ap; ap = ap->next) {

        if (equal(name, ap->name)) {

            if (check && (ap->flag & ALIASINUSE))

                return (NULL);

            return (ap);

        }

    }

    return (NULL);

}

/*

 * TODO - sort output

 */

int

aliascmd(argc, argv)

    int argc;

    char **argv;

{

    char *n, *v;

    int ret = 0;

    struct alias *ap;

    if (argc == 1) {

        int i;

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

            for (ap = atab[i]; ap; ap = ap->next) {

                if (*ap->name != '\0')

                    out1fmt("alias %s=%s\n", ap->name, ap->val);

            }

        return (0);

    }

    while ((n = *++argv) != NULL) {

        if ((v = strchr(n+1, '=')) == NULL) { /* n+1: funny ksh stuff */

            if ((ap = lookupalias(n, 0)) == NULL) {

                outfmt(out2, "alias: %s not found\n", n);

                ret = 1;

            } else

                out1fmt("alias %s=%s\n", n, ap->val);

        }

        else {

            *v++ = '\0';

            setalias(n, v);

        }

    }

    return (ret);

}

int

unaliascmd(argc, argv)

    int argc;

    char **argv;

{

    int i;

    while ((i = nextopt("a")) != '\0') {

        if (i == 'a') {

            rmaliases();

            return (0);

        }

    }

    for (i = 0; *argptr; argptr++)

        i = unalias(*argptr);

    return (i);

}

STATIC struct alias **

hashalias(p)

    char *p;

    {

    unsigned int hashval;

    hashval = *p << 4;

    while (*p)

        hashval+= *p++;

    return &atab[hashval % ATABSIZE];

}