xref: /freebsd/cddl/contrib/opensolaris/lib/libdtrace/common/dt_strtab.c (revision d9f0ce31900a48d1a2bfc1c8c86f79d1e831451a)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*
28  * Portions Copyright 2016 Pedro Giffuni.  All rights reserved.
29  */
30 
31 #pragma ident	"%Z%%M%	%I%	%E% SMI"
32 
33 #include <sys/types.h>
34 #include <sys/sysmacros.h>
35 #include <strings.h>
36 #include <stdlib.h>
37 #include <assert.h>
38 
39 #include <dt_strtab.h>
40 #include <dt_impl.h>
41 
42 static int
43 dt_strtab_grow(dt_strtab_t *sp)
44 {
45 	char *ptr, **bufs;
46 
47 	if ((ptr = malloc(sp->str_bufsz)) == NULL)
48 		return (-1);
49 
50 	bufs = realloc(sp->str_bufs, (sp->str_nbufs + 1) * sizeof (char *));
51 
52 	if (bufs == NULL) {
53 		free(ptr);
54 		return (-1);
55 	}
56 
57 	sp->str_nbufs++;
58 	sp->str_bufs = bufs;
59 	sp->str_ptr = ptr;
60 	sp->str_bufs[sp->str_nbufs - 1] = sp->str_ptr;
61 
62 	return (0);
63 }
64 
65 dt_strtab_t *
66 dt_strtab_create(size_t bufsz)
67 {
68 	dt_strtab_t *sp = malloc(sizeof (dt_strtab_t));
69 	uint_t nbuckets = _dtrace_strbuckets;
70 
71 	assert(bufsz != 0);
72 
73 	if (sp == NULL)
74 		return (NULL);
75 
76 	bzero(sp, sizeof (dt_strtab_t));
77 	sp->str_hash = calloc(nbuckets, sizeof (dt_strhash_t *));
78 
79 	if (sp->str_hash == NULL)
80 		goto err;
81 
82 	sp->str_hashsz = nbuckets;
83 	sp->str_bufs = NULL;
84 	sp->str_ptr = NULL;
85 	sp->str_nbufs = 0;
86 	sp->str_bufsz = bufsz;
87 	sp->str_nstrs = 1;
88 	sp->str_size = 1;
89 
90 	if (dt_strtab_grow(sp) == -1)
91 		goto err;
92 
93 	*sp->str_ptr++ = '\0';
94 	return (sp);
95 
96 err:
97 	dt_strtab_destroy(sp);
98 	return (NULL);
99 }
100 
101 void
102 dt_strtab_destroy(dt_strtab_t *sp)
103 {
104 	dt_strhash_t *hp, *hq;
105 	ulong_t i;
106 
107 	for (i = 0; i < sp->str_hashsz; i++) {
108 		for (hp = sp->str_hash[i]; hp != NULL; hp = hq) {
109 			hq = hp->str_next;
110 			free(hp);
111 		}
112 	}
113 
114 	for (i = 0; i < sp->str_nbufs; i++)
115 		free(sp->str_bufs[i]);
116 
117 	if (sp->str_hash != NULL)
118 		free(sp->str_hash);
119 	if (sp->str_bufs != NULL)
120 		free(sp->str_bufs);
121 
122 	free(sp);
123 }
124 
125 ulong_t
126 dt_strtab_hash(const char *key, size_t *len)
127 {
128 	ulong_t g, h = 0;
129 	const char *p;
130 	size_t n = 0;
131 
132 	for (p = key; *p != '\0'; p++, n++) {
133 		h = (h << 4) + *p;
134 
135 		if ((g = (h & 0xf0000000)) != 0) {
136 			h ^= (g >> 24);
137 			h ^= g;
138 		}
139 	}
140 
141 	if (len != NULL)
142 		*len = n;
143 
144 	return (h);
145 }
146 
147 static int
148 dt_strtab_compare(dt_strtab_t *sp, dt_strhash_t *hp,
149     const char *str, size_t len)
150 {
151 	ulong_t b = hp->str_buf;
152 	const char *buf = hp->str_data;
153 	size_t resid, n;
154 	int rv;
155 
156 	while (len != 0) {
157 		if (buf == sp->str_bufs[b] + sp->str_bufsz)
158 			buf = sp->str_bufs[++b];
159 
160 		resid = sp->str_bufs[b] + sp->str_bufsz - buf;
161 		n = MIN(resid, len);
162 
163 		if ((rv = strncmp(buf, str, n)) != 0)
164 			return (rv);
165 
166 		buf += n;
167 		str += n;
168 		len -= n;
169 	}
170 
171 	return (0);
172 }
173 
174 static int
175 dt_strtab_copyin(dt_strtab_t *sp, const char *str, size_t len)
176 {
177 	char *old_p = sp->str_ptr;
178 	ulong_t old_n = sp->str_nbufs;
179 
180 	ulong_t b = sp->str_nbufs - 1;
181 	size_t resid, n;
182 
183 	while (len != 0) {
184 		if (sp->str_ptr == sp->str_bufs[b] + sp->str_bufsz) {
185 			if (dt_strtab_grow(sp) == -1)
186 				goto err;
187 			b++;
188 		}
189 
190 		resid = sp->str_bufs[b] + sp->str_bufsz - sp->str_ptr;
191 		n = MIN(resid, len);
192 		bcopy(str, sp->str_ptr, n);
193 
194 		sp->str_ptr += n;
195 		str += n;
196 		len -= n;
197 	}
198 
199 	return (0);
200 
201 err:
202 	while (sp->str_nbufs != old_n)
203 		free(sp->str_bufs[--sp->str_nbufs]);
204 
205 	sp->str_ptr = old_p;
206 	return (-1);
207 }
208 
209 ssize_t
210 dt_strtab_index(dt_strtab_t *sp, const char *str)
211 {
212 	dt_strhash_t *hp;
213 	size_t len;
214 	ulong_t h;
215 
216 	if (str == NULL || str[0] == '\0')
217 		return (0); /* we keep a \0 at offset 0 to simplify things */
218 
219 	h = dt_strtab_hash(str, &len) % sp->str_hashsz;
220 
221 	for (hp = sp->str_hash[h]; hp != NULL; hp = hp->str_next) {
222 		if (dt_strtab_compare(sp, hp, str, len + 1) == 0)
223 			return (hp->str_off);
224 	}
225 
226 	return (-1);
227 }
228 
229 ssize_t
230 dt_strtab_insert(dt_strtab_t *sp, const char *str)
231 {
232 	dt_strhash_t *hp;
233 	size_t len;
234 	ssize_t off;
235 	ulong_t h;
236 
237 	if ((off = dt_strtab_index(sp, str)) != -1)
238 		return (off);
239 
240 	h = dt_strtab_hash(str, &len) % sp->str_hashsz;
241 
242 	/*
243 	 * Create a new hash bucket, initialize it, and insert it at the front
244 	 * of the hash chain for the appropriate bucket.
245 	 */
246 	if ((hp = malloc(sizeof (dt_strhash_t))) == NULL)
247 		return (-1L);
248 
249 	hp->str_data = sp->str_ptr;
250 	hp->str_buf = sp->str_nbufs - 1;
251 	hp->str_off = sp->str_size;
252 	hp->str_len = len;
253 	hp->str_next = sp->str_hash[h];
254 
255 	/*
256 	 * Now copy the string data into our buffer list, and then update
257 	 * the global counts of strings and bytes.  Return str's byte offset.
258 	 */
259 	if (dt_strtab_copyin(sp, str, len + 1) == -1)
260 		return (-1L);
261 
262 	sp->str_nstrs++;
263 	sp->str_size += len + 1;
264 	sp->str_hash[h] = hp;
265 
266 	return (hp->str_off);
267 }
268 
269 size_t
270 dt_strtab_size(const dt_strtab_t *sp)
271 {
272 	return (sp->str_size);
273 }
274 
275 ssize_t
276 dt_strtab_write(const dt_strtab_t *sp, dt_strtab_write_f *func, void *private)
277 {
278 	ssize_t res, total = 0;
279 	ulong_t i;
280 	size_t n;
281 
282 	for (i = 0; i < sp->str_nbufs; i++, total += res) {
283 		if (i == sp->str_nbufs - 1)
284 			n = sp->str_ptr - sp->str_bufs[i];
285 		else
286 			n = sp->str_bufsz;
287 
288 		if ((res = func(sp->str_bufs[i], n, total, private)) <= 0)
289 			break;
290 	}
291 
292 	if (total == 0 && sp->str_size != 0)
293 		return (-1);
294 
295 	return (total);
296 }
297