1/*	$NetBSD: alias.c,v 1.12 2003/08/07 09:05:29 agc Exp $	*/
2
3/*-
4 * Copyright (c) 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Kenneth Almquist.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 *    may be used to endorse or promote products derived from this software
20 *    without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35#include <sys/cdefs.h>
36#ifndef lint
37#if 0
38static char sccsid[] = "@(#)alias.c	8.3 (Berkeley) 5/4/95";
39#else
40__RCSID("$NetBSD: alias.c,v 1.12 2003/08/07 09:05:29 agc Exp $");
41#endif
42#endif /* not lint */
43
44#include <stdlib.h>
45#include "shell.h"
46#include "input.h"
47#include "output.h"
48#include "error.h"
49#include "memalloc.h"
50#include "mystring.h"
51#include "alias.h"
52#include "options.h"	/* XXX for argptr (should remove?) */
53#include "var.h"
54
55#define ATABSIZE 39
56
57struct alias *atab[ATABSIZE];
58
59STATIC void setalias(char *, char *);
60STATIC int unalias(char *);
61STATIC struct alias **hashalias(char *);
62
63STATIC
64void
65setalias(char *name, char *val)
66{
67	struct alias *ap, **app;
68
69	app = hashalias(name);
70	for (ap = *app; ap; ap = ap->next) {
71		if (equal(name, ap->name)) {
72			INTOFF;
73			ckfree(ap->val);
74			ap->val	= savestr(val);
75			INTON;
76			return;
77		}
78	}
79	/* not found */
80	INTOFF;
81	ap = ckmalloc(sizeof (struct alias));
82	ap->name = savestr(name);
83	/*
84	 * XXX - HACK: in order that the parser will not finish reading the
85	 * alias value off the input before processing the next alias, we
86	 * dummy up an extra space at the end of the alias.  This is a crock
87	 * and should be re-thought.  The idea (if you feel inclined to help)
88	 * is to avoid alias recursions.  The mechanism used is: when
89	 * expanding an alias, the value of the alias is pushed back on the
90	 * input as a string and a pointer to the alias is stored with the
91	 * string.  The alias is marked as being in use.  When the input
92	 * routine finishes reading the string, it markes the alias not
93	 * in use.  The problem is synchronization with the parser.  Since
94	 * it reads ahead, the alias is marked not in use before the
95	 * resulting token(s) is next checked for further alias sub.  The
96	 * H A C K is that we add a little fluff after the alias value
97	 * so that the string will not be exhausted.  This is a good
98	 * idea ------- ***NOT***
99	 */
100#ifdef notyet
101	ap->val = savestr(val);
102#else /* hack */
103	{
104	int len = strlen(val);
105	ap->val = ckmalloc(len + 2);
106	memcpy(ap->val, val, len);
107	ap->val[len] = ' ';	/* fluff */
108	ap->val[len+1] = '\0';
109	}
110#endif
111	ap->next = *app;
112	*app = ap;
113	INTON;
114}
115
116STATIC int
117unalias(char *name)
118{
119	struct alias *ap, **app;
120
121	app = hashalias(name);
122
123	for (ap = *app; ap; app = &(ap->next), ap = ap->next) {
124		if (equal(name, ap->name)) {
125			/*
126			 * if the alias is currently in use (i.e. its
127			 * buffer is being used by the input routine) we
128			 * just null out the name instead of freeing it.
129			 * We could clear it out later, but this situation
130			 * is so rare that it hardly seems worth it.
131			 */
132			if (ap->flag & ALIASINUSE)
133				*ap->name = '\0';
134			else {
135				INTOFF;
136				*app = ap->next;
137				ckfree(ap->name);
138				ckfree(ap->val);
139				ckfree(ap);
140				INTON;
141			}
142			return (0);
143		}
144	}
145
146	return (1);
147}
148
149#ifdef mkinit
150MKINIT void rmaliases(void);
151
152SHELLPROC {
153	rmaliases();
154}
155#endif
156
157void
158rmaliases(void)
159{
160	struct alias *ap, *tmp;
161	int i;
162
163	INTOFF;
164	for (i = 0; i < ATABSIZE; i++) {
165		ap = atab[i];
166		atab[i] = NULL;
167		while (ap) {
168			ckfree(ap->name);
169			ckfree(ap->val);
170			tmp = ap;
171			ap = ap->next;
172			ckfree(tmp);
173		}
174	}
175	INTON;
176}
177
178struct alias *
179lookupalias(char *name, int check)
180{
181	struct alias *ap = *hashalias(name);
182
183	for (; ap; ap = ap->next) {
184		if (equal(name, ap->name)) {
185			if (check && (ap->flag & ALIASINUSE))
186				return (NULL);
187			return (ap);
188		}
189	}
190
191	return (NULL);
192}
193
194char *
195get_alias_text(char *name)
196{
197	struct alias *ap;
198
199	ap = lookupalias(name, 0);
200	if (ap == NULL)
201		return NULL;
202	return ap->val;
203}
204
205/*
206 * TODO - sort output
207 */
208int
209aliascmd(int argc, char **argv)
210{
211	char *n, *v;
212	int ret = 0;
213	struct alias *ap;
214
215	if (argc == 1) {
216		int i;
217
218		for (i = 0; i < ATABSIZE; i++)
219			for (ap = atab[i]; ap; ap = ap->next) {
220				if (*ap->name != '\0') {
221					out1fmt("alias %s=", ap->name);
222					print_quoted(ap->val);
223					out1c('\n');
224				}
225			}
226		return (0);
227	}
228	while ((n = *++argv) != NULL) {
229		if ((v = strchr(n+1, '=')) == NULL) { /* n+1: funny ksh stuff */
230			if ((ap = lookupalias(n, 0)) == NULL) {
231				outfmt(out2, "alias: %s not found\n", n);
232				ret = 1;
233			} else {
234				out1fmt("alias %s=", n);
235				print_quoted(ap->val);
236				out1c('\n');
237			}
238		} else {
239			*v++ = '\0';
240			setalias(n, v);
241		}
242	}
243
244	return (ret);
245}
246
247int
248unaliascmd(int argc, char **argv)
249{
250	int i;
251
252	while ((i = nextopt("a")) != '\0') {
253		if (i == 'a') {
254			rmaliases();
255			return (0);
256		}
257	}
258	for (i = 0; *argptr; argptr++)
259		i = unalias(*argptr);
260
261	return (i);
262}
263
264STATIC struct alias **
265hashalias(char *p)
266{
267	unsigned int hashval;
268
269	hashval = *p << 4;
270	while (*p)
271		hashval+= *p++;
272	return &atab[hashval % ATABSIZE];
273}
274