1 /* $NetBSD: sysctl.c,v 1.38 2021/03/30 15:31:51 rillig Exp $ */
2
3 /*-
4 * Copyright (c) 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 #include <sys/cdefs.h>
33 #if defined(LIBC_SCCS) && !defined(lint)
34 #if 0
35 static char sccsid[] = "@(#)sysctl.c 8.2 (Berkeley) 1/4/94";
36 #else
37 __RCSID("$NetBSD: sysctl.c,v 1.38 2021/03/30 15:31:51 rillig Exp $");
38 #endif
39 #endif /* LIBC_SCCS and not lint */
40
41 #include "namespace.h"
42 #include <sys/param.h>
43 #define __COMPAT_SYSCTL
44 #include <sys/sysctl.h>
45
46 #include <assert.h>
47 #include <errno.h>
48 #include <paths.h>
49 #include <stdio.h>
50 #include <string.h>
51 #include <unistd.h>
52 #include "extern.h"
53
54 #ifdef __weak_alias
55 __weak_alias(sysctl,_sysctl)
56 #endif
57
58 /*
59 * handles requests off the user subtree
60 */
61 static int user_sysctl(const int *, u_int, void *, size_t *,
62 const void *, size_t);
63
64 /*
65 * copies out individual nodes taking target version into account
66 */
67 static size_t __cvt_node_out(uint, const struct sysctlnode *, void **,
68 size_t *);
69
70 #include <stdlib.h>
71
72 int
sysctl(const int * name,unsigned int namelen,void * oldp,size_t * oldlenp,const void * newp,size_t newlen)73 sysctl(const int *name, unsigned int namelen,
74 void *oldp, size_t *oldlenp,
75 const void *newp, size_t newlen)
76 {
77 size_t oldlen, savelen;
78 int error;
79
80 if (name[0] != CTL_USER)
81 return (__sysctl(name, namelen, oldp, oldlenp,
82 newp, newlen));
83
84 oldlen = (oldlenp == NULL) ? 0 : *oldlenp;
85 savelen = oldlen;
86 error = user_sysctl(name + 1, namelen - 1, oldp, &oldlen, newp, newlen);
87
88 if (error != 0) {
89 errno = error;
90 return (-1);
91 }
92
93 if (oldlenp != NULL) {
94 *oldlenp = oldlen;
95 if (oldp != NULL && oldlen > savelen) {
96 errno = ENOMEM;
97 return (-1);
98 }
99 }
100
101 return (0);
102 }
103
104 static int
user_sysctl(const int * name,unsigned int namelen,void * oldp,size_t * oldlenp,const void * newp,size_t newlen)105 user_sysctl(const int *name, unsigned int namelen,
106 void *oldp, size_t *oldlenp,
107 const void *newp, size_t newlen)
108 {
109 #define _INT(s, n, v, d) { \
110 .sysctl_flags = CTLFLAG_IMMEDIATE|CTLFLAG_PERMANENT| \
111 CTLTYPE_INT|SYSCTL_VERSION, \
112 .sysctl_size = sizeof(int), \
113 .sysctl_name = (s), \
114 .sysctl_num = (n), \
115 .sysctl_un.scu_idata = (v), \
116 .sysctl_desc = (d), \
117 }
118
119 /*
120 * the nodes under the "user" node
121 */
122 static const struct sysctlnode sysctl_usermib[] = {
123 {
124 .sysctl_flags = SYSCTL_VERSION|CTLFLAG_PERMANENT|
125 CTLTYPE_STRING,
126 .sysctl_size = sizeof(_PATH_STDPATH),
127 .sysctl_name = "cs_path",
128 .sysctl_num = USER_CS_PATH,
129 .sysctl_data = __UNCONST(_PATH_STDPATH),
130 .sysctl_desc = __UNCONST(
131 "A value for the PATH environment variable "
132 "that finds all the standard utilities"),
133 },
134 _INT("bc_base_max", USER_BC_BASE_MAX, BC_BASE_MAX,
135 "The maximum ibase/obase values in the bc(1) utility"),
136 _INT("bc_dim_max", USER_BC_DIM_MAX, BC_DIM_MAX,
137 "The maximum array size in the bc(1) utility"),
138 _INT("bc_scale_max", USER_BC_SCALE_MAX, BC_SCALE_MAX,
139 "The maximum scale value in the bc(1) utility"),
140 _INT("bc_string_max", USER_BC_STRING_MAX, BC_STRING_MAX,
141 "The maximum string length in the bc(1) utility"),
142 _INT("coll_weights_max", USER_COLL_WEIGHTS_MAX,
143 COLL_WEIGHTS_MAX, "The maximum number of weights that can "
144 "be assigned to any entry of the LC_COLLATE order keyword "
145 "in the locale definition file"),
146 _INT("expr_nest_max", USER_EXPR_NEST_MAX, EXPR_NEST_MAX,
147 "The maximum number of expressions that can be nested "
148 "within parenthesis by the expr(1) utility"),
149 _INT("line_max", USER_LINE_MAX, LINE_MAX, "The maximum length "
150 "in bytes of a text-processing utility's input line"),
151 _INT("re_dup_max", USER_RE_DUP_MAX, RE_DUP_MAX, "The maximum "
152 "number of repeated occurrences of a regular expression "
153 "permitted when using interval notation"),
154 _INT("posix2_version", USER_POSIX2_VERSION, _POSIX2_VERSION,
155 "The version of POSIX 1003.2 with which the system "
156 "attempts to comply"),
157 #ifdef _POSIX2_C_BIND
158 _INT("posix2_c_bind", USER_POSIX2_C_BIND, 1,
159 "Whether the system's C-language development facilities "
160 "support the C-Language Bindings Option"),
161 #else
162 _INT("posix2_c_bind", USER_POSIX2_C_BIND, 0,
163 "Whether the system's C-language development facilities "
164 "support the C-Language Bindings Option"),
165 #endif
166 #ifdef POSIX2_C_DEV
167 _INT("posix2_c_dev", USER_POSIX2_C_DEV, 1,
168 "Whether the system supports the C-Language Development "
169 "Utilities Option"),
170 #else
171 _INT("posix2_c_dev", USER_POSIX2_C_DEV, 0,
172 "Whether the system supports the C-Language Development "
173 "Utilities Option"),
174 #endif
175 #ifdef POSIX2_CHAR_TERM
176 _INT("posix2_char_term", USER_POSIX2_CHAR_TERM, 1,
177 "Whether the system supports at least one terminal type "
178 "capable of all operations described in POSIX 1003.2"),
179 #else
180 _INT("posix2_char_term", USER_POSIX2_CHAR_TERM, 0,
181 "Whether the system supports at least one terminal type "
182 "capable of all operations described in POSIX 1003.2"),
183 #endif
184 #ifdef POSIX2_FORT_DEV
185 _INT("posix2_fort_dev", USER_POSIX2_FORT_DEV, 1,
186 "Whether the system supports the FORTRAN Development "
187 "Utilities Option"),
188 #else
189 _INT("posix2_fort_dev", USER_POSIX2_FORT_DEV, 0,
190 "Whether the system supports the FORTRAN Development "
191 "Utilities Option"),
192 #endif
193 #ifdef POSIX2_FORT_RUN
194 _INT("posix2_fort_run", USER_POSIX2_FORT_RUN, 1,
195 "Whether the system supports the FORTRAN Runtime "
196 "Utilities Option"),
197 #else
198 _INT("posix2_fort_run", USER_POSIX2_FORT_RUN, 0,
199 "Whether the system supports the FORTRAN Runtime "
200 "Utilities Option"),
201 #endif
202 #ifdef POSIX2_LOCALEDEF
203 _INT("posix2_localedef", USER_POSIX2_LOCALEDEF, 1,
204 "Whether the system supports the creation of locales"),
205 #else
206 _INT("posix2_localedef", USER_POSIX2_LOCALEDEF, 0,
207 "Whether the system supports the creation of locales"),
208 #endif
209 #ifdef POSIX2_SW_DEV
210 _INT("posix2_sw_dev", USER_POSIX2_SW_DEV, 1,
211 "Whether the system supports the Software Development "
212 "Utilities Option"),
213 #else
214 _INT("posix2_sw_dev", USER_POSIX2_SW_DEV, 0,
215 "Whether the system supports the Software Development "
216 "Utilities Option"),
217 #endif
218 #ifdef POSIX2_UPE
219 _INT("posix2_upe", USER_POSIX2_UPE, 1,
220 "Whether the system supports the User Portability "
221 "Utilities Option"),
222 #else
223 _INT("posix2_upe", USER_POSIX2_UPE, 0,
224 "Whether the system supports the User Portability "
225 "Utilities Option"),
226 #endif
227 _INT("stream_max", USER_STREAM_MAX, FOPEN_MAX,
228 "The minimum maximum number of streams that a process "
229 "may have open at any one time"),
230 _INT("tzname_max", USER_TZNAME_MAX, NAME_MAX,
231 "The minimum maximum number of types supported for the "
232 "name of a timezone"),
233 _INT("atexit_max", USER_ATEXIT_MAX, -1,
234 "The maximum number of functions that may be registered "
235 "with atexit(3)"),
236 };
237 #undef _INT
238
239 static const int clen = sizeof(sysctl_usermib) /
240 sizeof(sysctl_usermib[0]);
241
242 const struct sysctlnode *node;
243 int ni;
244 size_t l, sz;
245
246 /*
247 * none of these nodes are writable and they're all terminal (for now)
248 */
249 if (namelen != 1)
250 return (EINVAL);
251
252 l = *oldlenp;
253 if (name[0] == CTL_QUERY) {
254 uint v;
255 node = newp;
256 if (node == NULL)
257 return (EINVAL);
258 else if (SYSCTL_VERS(node->sysctl_flags) == SYSCTL_VERS_1 &&
259 newlen == sizeof(struct sysctlnode))
260 v = SYSCTL_VERS_1;
261 else
262 return (EINVAL);
263
264 sz = 0;
265 for (ni = 0; ni < clen; ni++)
266 sz += __cvt_node_out(v, &sysctl_usermib[ni], &oldp, &l);
267 *oldlenp = sz;
268 return (0);
269 }
270
271 if (name[0] == CTL_DESCRIBE) {
272 /*
273 * XXX make sure this is larger than the largest
274 * "user" description
275 */
276 char buf[192];
277 struct sysctldesc *d1 = (void *)&buf[0], *d2 = oldp;
278 size_t d;
279
280 node = newp;
281 if (node != NULL &&
282 (SYSCTL_VERS(node->sysctl_flags) < SYSCTL_VERS_1 ||
283 newlen != sizeof(struct sysctlnode)))
284 return (EINVAL);
285
286 sz = 0;
287 for (ni = 0; ni < clen; ni++) {
288 memset(&buf[0], 0, sizeof(buf));
289 if (node != NULL &&
290 node->sysctl_num != sysctl_usermib[ni].sysctl_num)
291 continue;
292 d1->descr_num = sysctl_usermib[ni].sysctl_num;
293 d1->descr_ver = sysctl_usermib[ni].sysctl_ver;
294 if (sysctl_usermib[ni].sysctl_desc == NULL)
295 d1->descr_len = 1;
296 else {
297 size_t dlen;
298 (void)strlcpy(d1->descr_str,
299 sysctl_usermib[ni].sysctl_desc,
300 sizeof(buf) - sizeof(*d1));
301 dlen = strlen(d1->descr_str) + 1;
302 _DIAGASSERT(__type_fit(uint32_t, dlen));
303 d1->descr_len = (uint32_t)dlen;
304 }
305 d = (size_t)__sysc_desc_len(d1->descr_len);
306 if (d2 != NULL)
307 memcpy(d2, d1, d);
308 sz += d;
309 d2 = (void *)((char *)(void *)d2 + d);
310 if (node != NULL)
311 break;
312 }
313 *oldlenp = sz;
314 if (sz == 0 && node != NULL)
315 return (ENOENT);
316 return (0);
317
318 }
319
320 /*
321 * none of these nodes are writable
322 */
323 if (newp != NULL || newlen != 0)
324 return (EPERM);
325
326 node = &sysctl_usermib[0];
327 for (ni = 0; ni < clen; ni++)
328 if (name[0] == node[ni].sysctl_num)
329 break;
330 if (ni == clen)
331 return (EOPNOTSUPP);
332
333 node = &node[ni];
334 if (node->sysctl_flags & CTLFLAG_IMMEDIATE) {
335 switch (SYSCTL_TYPE(node->sysctl_flags)) {
336 case CTLTYPE_INT:
337 newp = &node->sysctl_idata;
338 break;
339 case CTLTYPE_QUAD:
340 newp = &node->sysctl_qdata;
341 break;
342 default:
343 return (EINVAL);
344 }
345 }
346 else
347 newp = node->sysctl_data;
348
349 l = MIN(l, node->sysctl_size);
350 if (oldp != NULL)
351 memcpy(oldp, newp, l);
352 *oldlenp = node->sysctl_size;
353
354 return (0);
355 }
356
357 static size_t
__cvt_node_out(uint v,const struct sysctlnode * n,void ** o,size_t * l)358 __cvt_node_out(uint v, const struct sysctlnode *n, void **o, size_t *l)
359 {
360 const void *src = n;
361 size_t sz;
362
363 switch (v) {
364 #if (SYSCTL_VERSION != SYSCTL_VERS_1)
365 #error __cvt_node_out: no support for SYSCTL_VERSION
366 #endif /* (SYSCTL_VERSION != SYSCTL_VERS_1) */
367
368 case SYSCTL_VERSION:
369 sz = sizeof(struct sysctlnode);
370 break;
371
372 default:
373 sz = 0;
374 break;
375 }
376
377 if (sz > 0 && *o != NULL && *l >= sz) {
378 memcpy(*o, src, sz);
379 *o = sz + (caddr_t)*o;
380 *l -= sz;
381 }
382
383 return(sz);
384 }
385