alias.c revision 127958 
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: head/bin/sh/alias.c 127958 2004-04-06 20:06:54Z markm $");
40
41#include <stdlib.h>
42#include "shell.h"
43#include "input.h"
44#include "output.h"
45#include "error.h"
46#include "memalloc.h"
47#include "mystring.h"
48#include "alias.h"
49#include "options.h"	/* XXX for argptr (should remove?) */
50
51#define ATABSIZE 39
52
53STATIC struct alias *atab[ATABSIZE];
54
55STATIC void setalias(char *, char *);
56STATIC int unalias(char *);
57STATIC struct alias **hashalias(char *);
58
59STATIC
60void
61setalias(char *name, char *val)
62{
63	struct alias *ap, **app;
64
65	app = hashalias(name);
66	for (ap = *app; ap; ap = ap->next) {
67		if (equal(name, ap->name)) {
68			INTOFF;
69			ckfree(ap->val);
70			ap->val	= savestr(val);
71			INTON;
72			return;
73		}
74	}
75	/* not found */
76	INTOFF;
77	ap = ckmalloc(sizeof (struct alias));
78	ap->name = savestr(name);
79	/*
80	 * XXX - HACK: in order that the parser will not finish reading the
81	 * alias value off the input before processing the next alias, we
82	 * dummy up an extra space at the end of the alias.  This is a crock
83	 * and should be re-thought.  The idea (if you feel inclined to help)
84	 * is to avoid alias recursions.  The mechanism used is: when
85	 * expanding an alias, the value of the alias is pushed back on the
86	 * input as a string and a pointer to the alias is stored with the
87	 * string.  The alias is marked as being in use.  When the input
88	 * routine finishes reading the string, it marks the alias not
89	 * in use.  The problem is synchronization with the parser.  Since
90	 * it reads ahead, the alias is marked not in use before the
91	 * resulting token(s) is next checked for further alias sub.  The
92	 * H A C K is that we add a little fluff after the alias value
93	 * so that the string will not be exhausted.  This is a good
94	 * idea ------- ***NOT***
95	 */
96#ifdef notyet
97	ap->val = savestr(val);
98#else /* hack */
99	{
100	int len = strlen(val);
101	ap->val = ckmalloc(len + 2);
102	memcpy(ap->val, val, len);
103	ap->val[len] = ' ';	/* fluff */
104	ap->val[len+1] = '\0';
105	}
106#endif
107	ap->flag = 0;
108	ap->next = *app;
109	*app = ap;
110	INTON;
111}
112
113STATIC int
114unalias(char *name)
115{
116	struct alias *ap, **app;
117
118	app = hashalias(name);
119
120	for (ap = *app; ap; app = &(ap->next), ap = ap->next) {
121		if (equal(name, ap->name)) {
122			/*
123			 * if the alias is currently in use (i.e. its
124			 * buffer is being used by the input routine) we
125			 * just null out the name instead of freeing it.
126			 * We could clear it out later, but this situation
127			 * is so rare that it hardly seems worth it.
128			 */
129			if (ap->flag & ALIASINUSE)
130				*ap->name = '\0';
131			else {
132				INTOFF;
133				*app = ap->next;
134				ckfree(ap->name);
135				ckfree(ap->val);
136				ckfree(ap);
137				INTON;
138			}
139			return (0);
140		}
141	}
142
143	return (1);
144}
145
146#ifdef mkinit
147MKINIT void rmaliases();
148
149SHELLPROC {
150	rmaliases();
151}
152#endif
153
154void
155rmaliases(void)
156{
157	struct alias *ap, *tmp;
158	int i;
159
160	INTOFF;
161	for (i = 0; i < ATABSIZE; i++) {
162		ap = atab[i];
163		atab[i] = NULL;
164		while (ap) {
165			ckfree(ap->name);
166			ckfree(ap->val);
167			tmp = ap;
168			ap = ap->next;
169			ckfree(tmp);
170		}
171	}
172	INTON;
173}
174
175struct alias *
176lookupalias(char *name, int check)
177{
178	struct alias *ap = *hashalias(name);
179
180	for (; ap; ap = ap->next) {
181		if (equal(name, ap->name)) {
182			if (check && (ap->flag & ALIASINUSE))
183				return (NULL);
184			return (ap);
185		}
186	}
187
188	return (NULL);
189}
190
191/*
192 * TODO - sort output
193 */
194int
195aliascmd(int argc, char **argv)
196{
197	char *n, *v;
198	int ret = 0;
199	struct alias *ap;
200
201	if (argc == 1) {
202		int i;
203
204		for (i = 0; i < ATABSIZE; i++)
205			for (ap = atab[i]; ap; ap = ap->next) {
206				if (*ap->name != '\0') {
207					out1fmt("alias %s=", ap->name);
208					out1qstr(ap->val);
209					out1c('\n');
210				}
211			}
212		return (0);
213	}
214	while ((n = *++argv) != NULL) {
215		if ((v = strchr(n+1, '=')) == NULL) /* n+1: funny ksh stuff */
216			if ((ap = lookupalias(n, 0)) == NULL) {
217				outfmt(out2, "alias: %s not found\n", n);
218				ret = 1;
219			} else {
220				out1fmt("alias %s=", n);
221				out1qstr(ap->val);
222				out1c('\n');
223			}
224		else {
225			*v++ = '\0';
226			setalias(n, v);
227		}
228	}
229
230	return (ret);
231}
232
233int
234unaliascmd(int argc __unused, char **argv __unused)
235{
236	int i;
237
238	while ((i = nextopt("a")) != '\0') {
239		if (i == 'a') {
240			rmaliases();
241			return (0);
242		}
243	}
244	for (i = 0; *argptr; argptr++)
245		i = unalias(*argptr);
246
247	return (i);
248}
249
250STATIC struct alias **
251hashalias(char *p)
252{
253	unsigned int hashval;
254
255	hashval = *p << 4;
256	while (*p)
257		hashval+= *p++;
258	return &atab[hashval % ATABSIZE];
259}
260