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