alias.c revision 179638 
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 179638 2008-06-07 16:19:28Z rse $");
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
50#define ATABSIZE 39
51
52STATIC struct alias *atab[ATABSIZE];
53
54STATIC void setalias(char *, char *);
55STATIC int unalias(char *);
56STATIC struct alias **hashalias(char *);
57
58STATIC
59void
60setalias(char *name, char *val)
61{
62	struct alias *ap, **app;
63
64	app = hashalias(name);
65	for (ap = *app; ap; ap = ap->next) {
66		if (equal(name, ap->name)) {
67			INTOFF;
68			ckfree(ap->val);
69			ap->val	= savestr(val);
70			INTON;
71			return;
72		}
73	}
74	/* not found */
75	INTOFF;
76	ap = ckmalloc(sizeof (struct alias));
77	ap->name = savestr(name);
78	/*
79	 * XXX - HACK: in order that the parser will not finish reading the
80	 * alias value off the input before processing the next alias, we
81	 * dummy up an extra space at the end of the alias.  This is a crock
82	 * and should be re-thought.  The idea (if you feel inclined to help)
83	 * is to avoid alias recursions.  The mechanism used is: when
84	 * expanding an alias, the value of the alias is pushed back on the
85	 * input as a string and a pointer to the alias is stored with the
86	 * string.  The alias is marked as being in use.  When the input
87	 * routine finishes reading the string, it marks the alias not
88	 * in use.  The problem is synchronization with the parser.  Since
89	 * it reads ahead, the alias is marked not in use before the
90	 * resulting token(s) is next checked for further alias sub.  The
91	 * H A C K is that we add a little fluff after the alias value
92	 * so that the string will not be exhausted.  This is a good
93	 * idea ------- ***NOT***
94	 */
95#ifdef notyet
96	ap->val = savestr(val);
97#else /* hack */
98	{
99	int len = strlen(val);
100	ap->val = ckmalloc(len + 2);
101	memcpy(ap->val, val, len);
102	ap->val[len] = ' ';	/* fluff */
103	ap->val[len+1] = '\0';
104	}
105#endif
106	ap->flag = 0;
107	ap->next = *app;
108	*app = ap;
109	INTON;
110}
111
112STATIC int
113unalias(char *name)
114{
115	struct alias *ap, **app;
116
117	app = hashalias(name);
118
119	for (ap = *app; ap; app = &(ap->next), ap = ap->next) {
120		if (equal(name, ap->name)) {
121			/*
122			 * if the alias is currently in use (i.e. its
123			 * buffer is being used by the input routine) we
124			 * just null out the name instead of freeing it.
125			 * We could clear it out later, but this situation
126			 * is so rare that it hardly seems worth it.
127			 */
128			if (ap->flag & ALIASINUSE)
129				*ap->name = '\0';
130			else {
131				INTOFF;
132				*app = ap->next;
133				ckfree(ap->name);
134				ckfree(ap->val);
135				ckfree(ap);
136				INTON;
137			}
138			return (0);
139		}
140	}
141
142	return (1);
143}
144
145#ifdef mkinit
146MKINIT void rmaliases(void);
147
148SHELLPROC {
149	rmaliases();
150}
151#endif
152
153void
154rmaliases(void)
155{
156	struct alias *ap, *tmp;
157	int i;
158
159	INTOFF;
160	for (i = 0; i < ATABSIZE; i++) {
161		ap = atab[i];
162		atab[i] = NULL;
163		while (ap) {
164			ckfree(ap->name);
165			ckfree(ap->val);
166			tmp = ap;
167			ap = ap->next;
168			ckfree(tmp);
169		}
170	}
171	INTON;
172}
173
174struct alias *
175lookupalias(char *name, int check)
176{
177	struct alias *ap = *hashalias(name);
178
179	for (; ap; ap = ap->next) {
180		if (equal(name, ap->name)) {
181			if (check && (ap->flag & ALIASINUSE))
182				return (NULL);
183			return (ap);
184		}
185	}
186
187	return (NULL);
188}
189
190/*
191 * TODO - sort output
192 */
193int
194aliascmd(int argc, char **argv)
195{
196	char *n, *v;
197	int ret = 0;
198	struct alias *ap;
199
200	if (argc == 1) {
201		int i;
202
203		for (i = 0; i < ATABSIZE; i++)
204			for (ap = atab[i]; ap; ap = ap->next) {
205				if (*ap->name != '\0') {
206					out1fmt("alias %s=", ap->name);
207					out1qstr(ap->val);
208					out1c('\n');
209				}
210			}
211		return (0);
212	}
213	while ((n = *++argv) != NULL) {
214		if ((v = strchr(n+1, '=')) == NULL) /* n+1: funny ksh stuff */
215			if ((ap = lookupalias(n, 0)) == NULL) {
216				outfmt(out2, "alias: %s not found\n", n);
217				ret = 1;
218			} else {
219				out1fmt("alias %s=", n);
220				out1qstr(ap->val);
221				out1c('\n');
222			}
223		else {
224			*v++ = '\0';
225			setalias(n, v);
226		}
227	}
228
229	return (ret);
230}
231
232int
233unaliascmd(int argc __unused, char **argv __unused)
234{
235	int i;
236
237	while ((i = nextopt("a")) != '\0') {
238		if (i == 'a') {
239			rmaliases();
240			return (0);
241		}
242	}
243	for (i = 0; *argptr; argptr++)
244		i |= unalias(*argptr);
245
246	return (i);
247}
248
249STATIC struct alias **
250hashalias(char *p)
251{
252	unsigned int hashval;
253
254	hashval = *p << 4;
255	while (*p)
256		hashval+= *p++;
257	return &atab[hashval % ATABSIZE];
258}
259