1/*-
2 * Copyright (c) 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Kenneth Almquist.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 4. Neither the name of the University nor the names of its contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33#ifndef lint
34#if 0
35static char sccsid[] = "@(#)alias.c	8.3 (Berkeley) 5/4/95";
36#endif
37#endif /* not lint */
38#include <sys/cdefs.h>
39__FBSDID("$FreeBSD$");
40
41#include <stdlib.h>
42#include "shell.h"
43#include "output.h"
44#include "error.h"
45#include "memalloc.h"
46#include "mystring.h"
47#include "alias.h"
48#include "options.h"	/* XXX for argptr (should remove?) */
49#include "builtins.h"
50
51#define ATABSIZE 39
52
53static struct alias *atab[ATABSIZE];
54static int aliases;
55
56static void setalias(const char *, const char *);
57static int unalias(const char *);
58static struct alias **hashalias(const char *);
59
60static
61void
62setalias(const char *name, const char *val)
63{
64	struct alias *ap, **app;
65
66	app = hashalias(name);
67	for (ap = *app; ap; ap = ap->next) {
68		if (equal(name, ap->name)) {
69			INTOFF;
70			ckfree(ap->val);
71			/* See HACK below. */
72#ifdef notyet
73			ap->val	= savestr(val);
74#else
75			{
76			size_t len = strlen(val);
77			ap->val = ckmalloc(len + 2);
78			memcpy(ap->val, val, len);
79			ap->val[len] = ' ';
80			ap->val[len+1] = '\0';
81			}
82#endif
83			INTON;
84			return;
85		}
86	}
87	/* not found */
88	INTOFF;
89	ap = ckmalloc(sizeof (struct alias));
90	ap->name = savestr(name);
91	/*
92	 * XXX - HACK: in order that the parser will not finish reading the
93	 * alias value off the input before processing the next alias, we
94	 * dummy up an extra space at the end of the alias.  This is a crock
95	 * and should be re-thought.  The idea (if you feel inclined to help)
96	 * is to avoid alias recursions.  The mechanism used is: when
97	 * expanding an alias, the value of the alias is pushed back on the
98	 * input as a string and a pointer to the alias is stored with the
99	 * string.  The alias is marked as being in use.  When the input
100	 * routine finishes reading the string, it marks the alias not
101	 * in use.  The problem is synchronization with the parser.  Since
102	 * it reads ahead, the alias is marked not in use before the
103	 * resulting token(s) is next checked for further alias sub.  The
104	 * H A C K is that we add a little fluff after the alias value
105	 * so that the string will not be exhausted.  This is a good
106	 * idea ------- ***NOT***
107	 */
108#ifdef notyet
109	ap->val = savestr(val);
110#else /* hack */
111	{
112	size_t len = strlen(val);
113	ap->val = ckmalloc(len + 2);
114	memcpy(ap->val, val, len);
115	ap->val[len] = ' ';	/* fluff */
116	ap->val[len+1] = '\0';
117	}
118#endif
119	ap->flag = 0;
120	ap->next = *app;
121	*app = ap;
122	aliases++;
123	INTON;
124}
125
126static int
127unalias(const char *name)
128{
129	struct alias *ap, **app;
130
131	app = hashalias(name);
132
133	for (ap = *app; ap; app = &(ap->next), ap = ap->next) {
134		if (equal(name, ap->name)) {
135			/*
136			 * if the alias is currently in use (i.e. its
137			 * buffer is being used by the input routine) we
138			 * just null out the name instead of freeing it.
139			 * We could clear it out later, but this situation
140			 * is so rare that it hardly seems worth it.
141			 */
142			if (ap->flag & ALIASINUSE)
143				*ap->name = '\0';
144			else {
145				INTOFF;
146				*app = ap->next;
147				ckfree(ap->name);
148				ckfree(ap->val);
149				ckfree(ap);
150				INTON;
151			}
152			aliases--;
153			return (0);
154		}
155	}
156
157	return (1);
158}
159
160static void
161rmaliases(void)
162{
163	struct alias *ap, *tmp;
164	int i;
165
166	INTOFF;
167	for (i = 0; i < ATABSIZE; i++) {
168		ap = atab[i];
169		atab[i] = NULL;
170		while (ap) {
171			ckfree(ap->name);
172			ckfree(ap->val);
173			tmp = ap;
174			ap = ap->next;
175			ckfree(tmp);
176		}
177	}
178	aliases = 0;
179	INTON;
180}
181
182struct alias *
183lookupalias(const char *name, int check)
184{
185	struct alias *ap = *hashalias(name);
186
187	for (; ap; ap = ap->next) {
188		if (equal(name, ap->name)) {
189			if (check && (ap->flag & ALIASINUSE))
190				return (NULL);
191			return (ap);
192		}
193	}
194
195	return (NULL);
196}
197
198static int
199comparealiases(const void *p1, const void *p2)
200{
201	const struct alias *const *a1 = p1;
202	const struct alias *const *a2 = p2;
203
204	return strcmp((*a1)->name, (*a2)->name);
205}
206
207static void
208printalias(const struct alias *a)
209{
210	char *p;
211
212	out1fmt("%s=", a->name);
213	/* Don't print the space added above. */
214	p = a->val + strlen(a->val) - 1;
215	*p = '\0';
216	out1qstr(a->val);
217	*p = ' ';
218	out1c('\n');
219}
220
221static void
222printaliases(void)
223{
224	int i, j;
225	struct alias **sorted, *ap;
226
227	sorted = ckmalloc(aliases * sizeof(*sorted));
228	j = 0;
229	for (i = 0; i < ATABSIZE; i++)
230		for (ap = atab[i]; ap; ap = ap->next)
231			if (*ap->name != '\0')
232				sorted[j++] = ap;
233	qsort(sorted, aliases, sizeof(*sorted), comparealiases);
234	for (i = 0; i < aliases; i++)
235		printalias(sorted[i]);
236	ckfree(sorted);
237}
238
239int
240aliascmd(int argc __unused, char **argv __unused)
241{
242	char *n, *v;
243	int ret = 0;
244	struct alias *ap;
245
246	nextopt("");
247
248	if (*argptr == NULL) {
249		printaliases();
250		return (0);
251	}
252	while ((n = *argptr++) != NULL) {
253		if ((v = strchr(n+1, '=')) == NULL) /* n+1: funny ksh stuff */
254			if ((ap = lookupalias(n, 0)) == NULL) {
255				warning("%s: not found", n);
256				ret = 1;
257			} else
258				printalias(ap);
259		else {
260			*v++ = '\0';
261			setalias(n, v);
262		}
263	}
264
265	return (ret);
266}
267
268int
269unaliascmd(int argc __unused, char **argv __unused)
270{
271	int i;
272
273	while ((i = nextopt("a")) != '\0') {
274		if (i == 'a') {
275			rmaliases();
276			return (0);
277		}
278	}
279	for (i = 0; *argptr; argptr++)
280		i |= unalias(*argptr);
281
282	return (i);
283}
284
285static struct alias **
286hashalias(const char *p)
287{
288	unsigned int hashval;
289
290	hashval = *p << 4;
291	while (*p)
292		hashval+= *p++;
293	return &atab[hashval % ATABSIZE];
294}
295