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