xref: /freebsd/bin/sh/alias.c (revision 9bd497b8354567454e075076d40c996e21bd6095)
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
35 static 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 
50 #define ATABSIZE 39
51 
52 STATIC struct alias *atab[ATABSIZE];
53 STATIC int aliases;
54 
55 STATIC void setalias(const char *, const char *);
56 STATIC int unalias(const char *);
57 STATIC struct alias **hashalias(const char *);
58 
59 STATIC
60 void
61 setalias(const char *name, const 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 	size_t 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 	aliases++;
111 	INTON;
112 }
113 
114 STATIC int
115 unalias(const char *name)
116 {
117 	struct alias *ap, **app;
118 
119 	app = hashalias(name);
120 
121 	for (ap = *app; ap; app = &(ap->next), ap = ap->next) {
122 		if (equal(name, ap->name)) {
123 			/*
124 			 * if the alias is currently in use (i.e. its
125 			 * buffer is being used by the input routine) we
126 			 * just null out the name instead of freeing it.
127 			 * We could clear it out later, but this situation
128 			 * is so rare that it hardly seems worth it.
129 			 */
130 			if (ap->flag & ALIASINUSE)
131 				*ap->name = '\0';
132 			else {
133 				INTOFF;
134 				*app = ap->next;
135 				ckfree(ap->name);
136 				ckfree(ap->val);
137 				ckfree(ap);
138 				INTON;
139 			}
140 			aliases--;
141 			return (0);
142 		}
143 	}
144 
145 	return (1);
146 }
147 
148 #ifdef mkinit
149 MKINIT void rmaliases(void);
150 
151 SHELLPROC {
152 	rmaliases();
153 }
154 #endif
155 
156 void
157 rmaliases(void)
158 {
159 	struct alias *ap, *tmp;
160 	int i;
161 
162 	INTOFF;
163 	for (i = 0; i < ATABSIZE; i++) {
164 		ap = atab[i];
165 		atab[i] = NULL;
166 		while (ap) {
167 			ckfree(ap->name);
168 			ckfree(ap->val);
169 			tmp = ap;
170 			ap = ap->next;
171 			ckfree(tmp);
172 		}
173 	}
174 	aliases = 0;
175 	INTON;
176 }
177 
178 struct alias *
179 lookupalias(const 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 static int
195 comparealiases(const void *p1, const void *p2)
196 {
197 	const struct alias *const *a1 = p1;
198 	const struct alias *const *a2 = p2;
199 
200 	return strcmp((*a1)->name, (*a2)->name);
201 }
202 
203 static void
204 printalias(const struct alias *a)
205 {
206 	char *p;
207 
208 	out1fmt("%s=", a->name);
209 	/* Don't print the space added above. */
210 	p = a->val + strlen(a->val) - 1;
211 	*p = '\0';
212 	out1qstr(a->val);
213 	*p = ' ';
214 	out1c('\n');
215 }
216 
217 static void
218 printaliases(void)
219 {
220 	int i, j;
221 	struct alias **sorted, *ap;
222 
223 	sorted = ckmalloc(aliases * sizeof(*sorted));
224 	j = 0;
225 	for (i = 0; i < ATABSIZE; i++)
226 		for (ap = atab[i]; ap; ap = ap->next)
227 			if (*ap->name != '\0')
228 				sorted[j++] = ap;
229 	qsort(sorted, aliases, sizeof(*sorted), comparealiases);
230 	for (i = 0; i < aliases; i++)
231 		printalias(sorted[i]);
232 	ckfree(sorted);
233 }
234 
235 int
236 aliascmd(int argc, char **argv)
237 {
238 	char *n, *v;
239 	int ret = 0;
240 	struct alias *ap;
241 
242 	if (argc == 1) {
243 		printaliases();
244 		return (0);
245 	}
246 	while ((n = *++argv) != NULL) {
247 		if ((v = strchr(n+1, '=')) == NULL) /* n+1: funny ksh stuff */
248 			if ((ap = lookupalias(n, 0)) == NULL) {
249 				outfmt(out2, "alias: %s not found\n", n);
250 				ret = 1;
251 			} else
252 				printalias(ap);
253 		else {
254 			*v++ = '\0';
255 			setalias(n, v);
256 		}
257 	}
258 
259 	return (ret);
260 }
261 
262 int
263 unaliascmd(int argc __unused, char **argv __unused)
264 {
265 	int i;
266 
267 	while ((i = nextopt("a")) != '\0') {
268 		if (i == 'a') {
269 			rmaliases();
270 			return (0);
271 		}
272 	}
273 	for (i = 0; *argptr; argptr++)
274 		i |= unalias(*argptr);
275 
276 	return (i);
277 }
278 
279 STATIC struct alias **
280 hashalias(const char *p)
281 {
282 	unsigned int hashval;
283 
284 	hashval = *p << 4;
285 	while (*p)
286 		hashval+= *p++;
287 	return &atab[hashval % ATABSIZE];
288 }
289