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
38 static 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
57 struct alias *atab[ATABSIZE];
58
59 STATIC void setalias(char *, char *);
60 STATIC int unalias(char *);
61 STATIC struct alias **hashalias(char *);
62
63 STATIC
64 void
setalias(char * name,char * val)65 setalias(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
116 STATIC int
unalias(char * name)117 unalias(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
150 MKINIT void rmaliases(void);
151
152 SHELLPROC {
153 rmaliases();
154 }
155 #endif
156
157 void
rmaliases(void)158 rmaliases(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
178 struct alias *
lookupalias(char * name,int check)179 lookupalias(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
194 char *
get_alias_text(char * name)195 get_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 */
208 int
aliascmd(int argc,char ** argv)209 aliascmd(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
247 int
unaliascmd(int argc,char ** argv)248 unaliascmd(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
264 STATIC struct alias **
hashalias(char * p)265 hashalias(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