FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_hints.c
1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2000,2001 Peter Wemm <peter@FreeBSD.org>
5 * 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 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31
32 #include <sys/param.h>
33 #include <sys/lock.h>
34 #include <sys/kernel.h>
35 #include <sys/malloc.h>
36 #include <sys/mutex.h>
37 #include <sys/sysctl.h>
38 #include <sys/systm.h>
39 #include <sys/bus.h>
40
41 #define FBACK_MDENV 0 /* MD env (e.g. loader.conf) */
42 #define FBACK_STENV 1 /* Static env */
43 #define FBACK_STATIC 2 /* static_hints */
44
45 /*
46 * We'll use hintenv_merged to indicate that the dynamic environment has been
47 * properly prepared for hint usage. This implies that the dynamic environment
48 * has already been setup (dynamic_kenv) and that we have added any supplied
49 * static_hints to the dynamic environment.
50 */
51 static bool hintenv_merged;
52 /* Static environment and static hints cannot change, so we'll skip known bad */
53 static bool stenv_skip;
54 static bool sthints_skip;
55 /*
56 * Access functions for device resources.
57 */
58
59 static void
60 static_hints_to_env(void *data __unused)
61 {
62 const char *cp;
63 char *line, *eq;
64 int eqidx, i;
65
66 cp = static_hints;
67 while (cp && *cp != '\0') {
68 eq = strchr(cp, '=');
69 if (eq == NULL)
70 /* Bad hint value */
71 continue;
72 eqidx = eq - cp;
73
74 i = strlen(cp);
75 line = malloc(i + 1, M_TEMP, M_WAITOK);
76 strcpy(line, cp);
77 line[eqidx] = line[i] = '\0';
78 /*
79 * Before adding a hint to the dynamic environment, check if
80 * another value for said hint has already been added. This is
81 * needed because static environment overrides static hints and
82 * dynamic environment overrides all.
83 */
84 if (testenv(line) == 0)
85 kern_setenv(line, line + eqidx + 1);
86 free(line, M_TEMP);
87 cp += i + 1;
88 }
89 hintenv_merged = true;
90 }
91
92 /* Any time after dynamic env is setup */
93 SYSINIT(hintenv, SI_SUB_KMEM + 1, SI_ORDER_SECOND, static_hints_to_env, NULL);
94
95 /*
96 * Checks the environment to see if we even have any hints. If it has no hints,
97 * then res_find can take the hint that there's no point in searching it and
98 * either move on to the next environment or fail early.
99 */
100 static bool
101 _res_checkenv(char *envp)
102 {
103 char *cp;
104
105 cp = envp;
106 while (cp) {
107 if (strncmp(cp, "hint.", 5) == 0)
108 return (true);
109 while (*cp != '\0')
110 cp++;
111 cp++;
112 if (*cp == '\0')
113 break;
114 }
115 return (false);
116 }
117
118 /*
119 * Evil wildcarding resource string lookup.
120 * This walks the supplied env string table and returns a match.
121 * The start point can be remembered for incremental searches.
122 */
123 static int
124 res_find(char **hintp_cookie, int *line, int *startln,
125 const char *name, int *unit, const char *resname, const char *value,
126 const char **ret_name, int *ret_namelen, int *ret_unit,
127 const char **ret_resname, int *ret_resnamelen, const char **ret_value)
128 {
129 int fbacklvl = FBACK_MDENV, i = 0, n = 0, namelen;
130 char r_name[32];
131 int r_unit;
132 char r_resname[32];
133 char r_value[128];
134 const char *s, *cp;
135 char *hintp, *p;
136 bool dyn_used = false;
137
138
139 /*
140 * We are expecting that the caller will pass us a hintp_cookie that
141 * they are tracking. Upon entry, if *hintp_cookie is *not* set, this
142 * indicates to us that we should be figuring out based on the current
143 * environment where to search. This keeps us sane throughout the
144 * entirety of a single search.
145 */
146 if (*hintp_cookie == NULL) {
147 hintp = NULL;
148 if (hintenv_merged) {
149 /*
150 * static_hints, if it was previously used, has
151 * already been folded in to the environment
152 * by this point.
153 */
154 mtx_lock(&kenv_lock);
155 cp = kenvp[0];
156 for (i = 0; cp != NULL; cp = kenvp[++i]) {
157 if (!strncmp(cp, "hint.", 5)) {
158 hintp = kenvp[0];
159 break;
160 }
161 }
162 mtx_unlock(&kenv_lock);
163 dyn_used = true;
164 } else {
165 /*
166 * We'll have a chance to keep coming back here until
167 * we've actually exhausted all of our possibilities.
168 * We might have chosen the MD/Static env because it
169 * had some kind of hints, but perhaps it didn't have
170 * the hint we are looking for. We don't provide any
171 * fallback when searching the dynamic environment.
172 */
173 fallback:
174 if (dyn_used || fbacklvl >= FBACK_STATIC)
175 return (ENOENT);
176
177 switch (fbacklvl) {
178 case FBACK_MDENV:
179 fbacklvl++;
180 if (_res_checkenv(md_envp)) {
181 hintp = md_envp;
182 break;
183 }
184
185 /* FALLTHROUGH */
186 case FBACK_STENV:
187 fbacklvl++;
188 if (!stenv_skip && _res_checkenv(kern_envp)) {
189 hintp = kern_envp;
190 break;
191 } else
192 stenv_skip = true;
193
194 /* FALLTHROUGH */
195 case FBACK_STATIC:
196 fbacklvl++;
197 /* We'll fallback to static_hints if needed/can */
198 if (!sthints_skip &&
199 _res_checkenv(static_hints))
200 hintp = static_hints;
201 else
202 sthints_skip = true;
203
204 break;
205 default:
206 return (ENOENT);
207 }
208 }
209
210 if (hintp == NULL)
211 return (ENOENT);
212 *hintp_cookie = hintp;
213 } else {
214 hintp = *hintp_cookie;
215 if (hintenv_merged && hintp == kenvp[0])
216 dyn_used = true;
217 else
218 /*
219 * If we aren't using the dynamic environment, we need
220 * to run through the proper fallback procedure again.
221 * This is so that we do continuations right if we're
222 * working with *line and *startln.
223 */
224 goto fallback;
225 }
226
227 if (dyn_used) {
228 mtx_lock(&kenv_lock);
229 i = 0;
230 }
231
232 if (name)
233 namelen = strlen(name);
234 cp = hintp;
235 while (cp) {
236 (*line)++;
237 if (strncmp(cp, "hint.", 5) != 0)
238 goto nexthint;
239 if (name && strncmp(cp + 5, name, namelen) != 0)
240 goto nexthint;
241 n = sscanf(cp + 5, "%32[^.].%d.%32[^=]=%127s", r_name, &r_unit,
242 r_resname, r_value);
243 if (n != 4) {
244 printf("CONFIG: invalid hint '%s'\n", cp);
245 p = strchr(cp, 'h');
246 *p = 'H';
247 goto nexthint;
248 }
249 if (startln && *startln >= 0 && *line < *startln)
250 goto nexthint;
251 if (name && strcmp(name, r_name) != 0)
252 goto nexthint;
253 if (unit && *unit != r_unit)
254 goto nexthint;
255 if (resname && strcmp(resname, r_resname) != 0)
256 goto nexthint;
257 if (value && strcmp(value, r_value) != 0)
258 goto nexthint;
259 /* Successfully found a hint matching all criteria */
260 break;
261 nexthint:
262 if (dyn_used) {
263 cp = kenvp[++i];
264 if (cp == NULL)
265 break;
266 } else {
267 while (*cp != '\0')
268 cp++;
269 cp++;
270 if (*cp == '\0') {
271 cp = NULL;
272 break;
273 }
274 }
275 }
276 if (dyn_used)
277 mtx_unlock(&kenv_lock);
278 if (cp == NULL)
279 goto fallback;
280
281 s = cp;
282 /* This is a bit of a hack, but at least is reentrant */
283 /* Note that it returns some !unterminated! strings. */
284 s = strchr(s, '.') + 1; /* start of device */
285 if (ret_name)
286 *ret_name = s;
287 s = strchr(s, '.') + 1; /* start of unit */
288 if (ret_namelen && ret_name)
289 *ret_namelen = s - *ret_name - 1; /* device length */
290 if (ret_unit)
291 *ret_unit = r_unit;
292 s = strchr(s, '.') + 1; /* start of resname */
293 if (ret_resname)
294 *ret_resname = s;
295 s = strchr(s, '=') + 1; /* start of value */
296 if (ret_resnamelen && ret_resname)
297 *ret_resnamelen = s - *ret_resname - 1; /* value len */
298 if (ret_value)
299 *ret_value = s;
300 if (startln) /* line number for anchor */
301 *startln = *line + 1;
302 return 0;
303 }
304
305 /*
306 * Search all the data sources for matches to our query. We look for
307 * dynamic hints first as overrides for static or fallback hints.
308 */
309 static int
310 resource_find(int *line, int *startln,
311 const char *name, int *unit, const char *resname, const char *value,
312 const char **ret_name, int *ret_namelen, int *ret_unit,
313 const char **ret_resname, int *ret_resnamelen, const char **ret_value)
314 {
315 int i;
316 int un;
317 char *hintp;
318
319 *line = 0;
320 hintp = NULL;
321
322 /* Search for exact unit matches first */
323 i = res_find(&hintp, line, startln, name, unit, resname, value,
324 ret_name, ret_namelen, ret_unit, ret_resname, ret_resnamelen,
325 ret_value);
326 if (i == 0)
327 return 0;
328 if (unit == NULL)
329 return ENOENT;
330 /* If we are still here, search for wildcard matches */
331 un = -1;
332 i = res_find(&hintp, line, startln, name, &un, resname, value,
333 ret_name, ret_namelen, ret_unit, ret_resname, ret_resnamelen,
334 ret_value);
335 if (i == 0)
336 return 0;
337 return ENOENT;
338 }
339
340 int
341 resource_int_value(const char *name, int unit, const char *resname, int *result)
342 {
343 int error;
344 const char *str;
345 char *op;
346 unsigned long val;
347 int line;
348
349 line = 0;
350 error = resource_find(&line, NULL, name, &unit, resname, NULL,
351 NULL, NULL, NULL, NULL, NULL, &str);
352 if (error)
353 return error;
354 if (*str == '\0')
355 return EFTYPE;
356 val = strtoul(str, &op, 0);
357 if (*op != '\0')
358 return EFTYPE;
359 *result = val;
360 return 0;
361 }
362
363 int
364 resource_long_value(const char *name, int unit, const char *resname,
365 long *result)
366 {
367 int error;
368 const char *str;
369 char *op;
370 unsigned long val;
371 int line;
372
373 line = 0;
374 error = resource_find(&line, NULL, name, &unit, resname, NULL,
375 NULL, NULL, NULL, NULL, NULL, &str);
376 if (error)
377 return error;
378 if (*str == '\0')
379 return EFTYPE;
380 val = strtoul(str, &op, 0);
381 if (*op != '\0')
382 return EFTYPE;
383 *result = val;
384 return 0;
385 }
386
387 int
388 resource_string_value(const char *name, int unit, const char *resname,
389 const char **result)
390 {
391 int error;
392 const char *str;
393 int line;
394
395 line = 0;
396 error = resource_find(&line, NULL, name, &unit, resname, NULL,
397 NULL, NULL, NULL, NULL, NULL, &str);
398 if (error)
399 return error;
400 *result = str;
401 return 0;
402 }
403
404 /*
405 * This is a bit nasty, but allows us to not modify the env strings.
406 */
407 static const char *
408 resource_string_copy(const char *s, int len)
409 {
410 static char stringbuf[256];
411 static int offset = 0;
412 const char *ret;
413
414 if (len == 0)
415 len = strlen(s);
416 if (len > 255)
417 return NULL;
418 if ((offset + len + 1) > 255)
419 offset = 0;
420 bcopy(s, &stringbuf[offset], len);
421 stringbuf[offset + len] = '\0';
422 ret = &stringbuf[offset];
423 offset += len + 1;
424 return ret;
425 }
426
427 /*
428 * err = resource_find_match(&anchor, &name, &unit, resname, value)
429 * Iteratively fetch a list of devices wired "at" something
430 * res and value are restrictions. eg: "at", "scbus0".
431 * For practical purposes, res = required, value = optional.
432 * *name and *unit are set.
433 * set *anchor to zero before starting.
434 */
435 int
436 resource_find_match(int *anchor, const char **name, int *unit,
437 const char *resname, const char *value)
438 {
439 const char *found_name;
440 int found_namelen;
441 int found_unit;
442 int ret;
443 int newln;
444
445 newln = *anchor;
446 ret = resource_find(anchor, &newln, NULL, NULL, resname, value,
447 &found_name, &found_namelen, &found_unit, NULL, NULL, NULL);
448 if (ret == 0) {
449 *name = resource_string_copy(found_name, found_namelen);
450 *unit = found_unit;
451 }
452 *anchor = newln;
453 return ret;
454 }
455
456
457 /*
458 * err = resource_find_dev(&anchor, name, &unit, res, value);
459 * Iterate through a list of devices, returning their unit numbers.
460 * res and value are optional restrictions. eg: "at", "scbus0".
461 * *unit is set to the value.
462 * set *anchor to zero before starting.
463 */
464 int
465 resource_find_dev(int *anchor, const char *name, int *unit,
466 const char *resname, const char *value)
467 {
468 int found_unit;
469 int newln;
470 int ret;
471
472 newln = *anchor;
473 ret = resource_find(anchor, &newln, name, NULL, resname, value,
474 NULL, NULL, &found_unit, NULL, NULL, NULL);
475 if (ret == 0) {
476 *unit = found_unit;
477 }
478 *anchor = newln;
479 return ret;
480 }
481
482 /*
483 * Check to see if a device is disabled via a disabled hint.
484 */
485 int
486 resource_disabled(const char *name, int unit)
487 {
488 int error, value;
489
490 error = resource_int_value(name, unit, "disabled", &value);
491 if (error)
492 return (0);
493 return (value);
494 }
495
496 /*
497 * Clear a value associated with a device by removing it from
498 * the kernel environment. This only removes a hint for an
499 * exact unit.
500 */
501 int
502 resource_unset_value(const char *name, int unit, const char *resname)
503 {
504 char varname[128];
505 const char *retname, *retvalue;
506 int error, line;
507 size_t len;
508
509 line = 0;
510 error = resource_find(&line, NULL, name, &unit, resname, NULL,
511 &retname, NULL, NULL, NULL, NULL, &retvalue);
512 if (error)
513 return (error);
514
515 retname -= strlen("hint.");
516 len = retvalue - retname - 1;
517 if (len > sizeof(varname) - 1)
518 return (ENAMETOOLONG);
519 memcpy(varname, retname, len);
520 varname[len] = '\0';
521 return (kern_unsetenv(varname));
522 }
Cache object: 555c05cb2de991c07c9484317e80b0a0
|