1 /* $OpenBSD: kern_subr.c,v 1.52 2023/01/31 15:18:56 deraadt Exp $ */
2 /* $NetBSD: kern_subr.c,v 1.15 1996/04/09 17:21:56 ragge Exp $ */
3
4 /*
5 * Copyright (c) 1982, 1986, 1991, 1993
6 * The Regents of the University of California. All rights reserved.
7 * (c) UNIX System Laboratories, Inc.
8 * All or some portions of this file are derived from material licensed
9 * to the University of California by American Telephone and Telegraph
10 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
11 * the permission of UNIX System Laboratories, Inc.
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
16 * 1. Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution.
21 * 3. Neither the name of the University nor the names of its contributors
22 * may be used to endorse or promote products derived from this software
23 * without specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * SUCH DAMAGE.
36 *
37 * @(#)kern_subr.c 8.3 (Berkeley) 1/21/94
38 */
39
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/proc.h>
43 #include <sys/sched.h>
44 #include <sys/malloc.h>
45 #include <sys/queue.h>
46 #include <uvm/uvm_extern.h>
47
48 #ifdef PMAP_CHECK_COPYIN
49
50 static inline int check_copyin(struct proc *, const void *, size_t);
51 extern int _copyinstr(const void *, void *, size_t, size_t *);
52 extern int _copyin(const void *uaddr, void *kaddr, size_t len);
53
54 /*
55 * If range overlaps an check_copyin region, return EFAULT
56 */
57 static inline int
check_copyin(struct proc * p,const void * vstart,size_t len)58 check_copyin(struct proc *p, const void *vstart, size_t len)
59 {
60 struct vm_map *map = &p->p_vmspace->vm_map;
61 const vaddr_t start = (vaddr_t)vstart;
62 const vaddr_t end = start + len;
63 int i, max;
64
65 /* XXX if the array was sorted, we could shortcut */
66 max = map->check_copyin_count;
67 membar_consumer();
68 for (i = 0; i < max; i++) {
69 vaddr_t s = map->check_copyin[i].start;
70 vaddr_t e = map->check_copyin[i].end;
71 if ((start >= s && start < e) || (end > s && end < e))
72 return EFAULT;
73 }
74 return (0);
75 }
76
77 int
copyinstr(const void * uaddr,void * kaddr,size_t len,size_t * done)78 copyinstr(const void *uaddr, void *kaddr, size_t len, size_t *done)
79 {
80 size_t alen;
81 int error;
82
83 /*
84 * Must do the copyin checks after figuring out the string length,
85 * the buffer size length may cross into another ELF segment
86 */
87 error = _copyinstr(uaddr, kaddr, len, &alen);
88 if (PMAP_CHECK_COPYIN && error == 0)
89 error = check_copyin(curproc, uaddr, alen);
90 if (done)
91 *done = alen;
92 return (error);
93 }
94
95 int
copyin(const void * uaddr,void * kaddr,size_t len)96 copyin(const void *uaddr, void *kaddr, size_t len)
97 {
98 int error = 0;
99
100 if (PMAP_CHECK_COPYIN)
101 error = check_copyin(curproc, uaddr, len);
102 if (error == 0)
103 error = _copyin(uaddr, kaddr, len);
104 return (error);
105 }
106 #endif /* PMAP_CHECK_COPYIN */
107
108 int
uiomove(void * cp,size_t n,struct uio * uio)109 uiomove(void *cp, size_t n, struct uio *uio)
110 {
111 struct iovec *iov;
112 size_t cnt;
113 int error = 0;
114
115 #ifdef DIAGNOSTIC
116 if (uio->uio_rw != UIO_READ && uio->uio_rw != UIO_WRITE)
117 panic("uiomove: mode");
118 if (uio->uio_segflg == UIO_USERSPACE && uio->uio_procp != curproc)
119 panic("uiomove: proc");
120 #endif
121
122 if (n > uio->uio_resid)
123 n = uio->uio_resid;
124
125 while (n > 0) {
126 iov = uio->uio_iov;
127 cnt = iov->iov_len;
128 if (cnt == 0) {
129 KASSERT(uio->uio_iovcnt > 0);
130 uio->uio_iov++;
131 uio->uio_iovcnt--;
132 continue;
133 }
134 if (cnt > n)
135 cnt = n;
136 switch (uio->uio_segflg) {
137
138 case UIO_USERSPACE:
139 sched_pause(preempt);
140 if (uio->uio_rw == UIO_READ)
141 error = copyout(cp, iov->iov_base, cnt);
142 else
143 error = copyin(iov->iov_base, cp, cnt);
144 if (error)
145 return (error);
146 break;
147
148 case UIO_SYSSPACE:
149 if (uio->uio_rw == UIO_READ)
150 error = kcopy(cp, iov->iov_base, cnt);
151 else
152 error = kcopy(iov->iov_base, cp, cnt);
153 if (error)
154 return(error);
155 }
156 iov->iov_base = (caddr_t)iov->iov_base + cnt;
157 iov->iov_len -= cnt;
158 uio->uio_resid -= cnt;
159 uio->uio_offset += cnt;
160 cp = (caddr_t)cp + cnt;
161 n -= cnt;
162 }
163 return (error);
164 }
165
166 /*
167 * Give next character to user as result of read.
168 */
169 int
ureadc(int c,struct uio * uio)170 ureadc(int c, struct uio *uio)
171 {
172 struct iovec *iov;
173
174 if (uio->uio_resid == 0)
175 #ifdef DIAGNOSTIC
176 panic("ureadc: zero resid");
177 #else
178 return (EINVAL);
179 #endif
180 again:
181 if (uio->uio_iovcnt <= 0)
182 #ifdef DIAGNOSTIC
183 panic("ureadc: non-positive iovcnt");
184 #else
185 return (EINVAL);
186 #endif
187 iov = uio->uio_iov;
188 if (iov->iov_len <= 0) {
189 uio->uio_iovcnt--;
190 uio->uio_iov++;
191 goto again;
192 }
193 switch (uio->uio_segflg) {
194
195 case UIO_USERSPACE:
196 {
197 char tmp = c;
198
199 if (copyout(&tmp, iov->iov_base, sizeof(char)) != 0)
200 return (EFAULT);
201 }
202 break;
203
204 case UIO_SYSSPACE:
205 *(char *)iov->iov_base = c;
206 break;
207 }
208 iov->iov_base = (caddr_t)iov->iov_base + 1;
209 iov->iov_len--;
210 uio->uio_resid--;
211 uio->uio_offset++;
212 return (0);
213 }
214
215 /*
216 * General routine to allocate a hash table.
217 */
218 void *
hashinit(int elements,int type,int flags,u_long * hashmask)219 hashinit(int elements, int type, int flags, u_long *hashmask)
220 {
221 u_long hashsize, i;
222 LIST_HEAD(generic, generic) *hashtbl;
223
224 if (elements <= 0)
225 panic("hashinit: bad cnt");
226 if ((elements & (elements - 1)) == 0)
227 hashsize = elements;
228 else
229 for (hashsize = 1; hashsize < elements; hashsize <<= 1)
230 continue;
231 hashtbl = mallocarray(hashsize, sizeof(*hashtbl), type, flags);
232 if (hashtbl == NULL)
233 return NULL;
234 for (i = 0; i < hashsize; i++)
235 LIST_INIT(&hashtbl[i]);
236 *hashmask = hashsize - 1;
237 return (hashtbl);
238 }
239
240 void
hashfree(void * hash,int elements,int type)241 hashfree(void *hash, int elements, int type)
242 {
243 u_long hashsize;
244 LIST_HEAD(generic, generic) *hashtbl = hash;
245
246 if (elements <= 0)
247 panic("hashfree: bad cnt");
248 if ((elements & (elements - 1)) == 0)
249 hashsize = elements;
250 else
251 for (hashsize = 1; hashsize < elements; hashsize <<= 1)
252 continue;
253
254 free(hashtbl, type, sizeof(*hashtbl) * hashsize);
255 }
256
257 /*
258 * "startup hook" types, functions, and variables.
259 */
260
261 struct hook_desc_head startuphook_list =
262 TAILQ_HEAD_INITIALIZER(startuphook_list);
263
264 void *
hook_establish(struct hook_desc_head * head,int tail,void (* fn)(void *),void * arg)265 hook_establish(struct hook_desc_head *head, int tail, void (*fn)(void *),
266 void *arg)
267 {
268 struct hook_desc *hdp;
269
270 hdp = malloc(sizeof(*hdp), M_DEVBUF, M_NOWAIT);
271 if (hdp == NULL)
272 return (NULL);
273
274 hdp->hd_fn = fn;
275 hdp->hd_arg = arg;
276 if (tail)
277 TAILQ_INSERT_TAIL(head, hdp, hd_list);
278 else
279 TAILQ_INSERT_HEAD(head, hdp, hd_list);
280
281 return (hdp);
282 }
283
284 void
hook_disestablish(struct hook_desc_head * head,void * vhook)285 hook_disestablish(struct hook_desc_head *head, void *vhook)
286 {
287 struct hook_desc *hdp;
288
289 #ifdef DIAGNOSTIC
290 for (hdp = TAILQ_FIRST(head); hdp != NULL;
291 hdp = TAILQ_NEXT(hdp, hd_list))
292 if (hdp == vhook)
293 break;
294 if (hdp == NULL)
295 return;
296 #endif
297 hdp = vhook;
298 TAILQ_REMOVE(head, hdp, hd_list);
299 free(hdp, M_DEVBUF, sizeof(*hdp));
300 }
301
302 /*
303 * Run hooks. Startup hooks are invoked right after scheduler_start but
304 * before root is mounted. Shutdown hooks are invoked immediately before the
305 * system is halted or rebooted, i.e. after file systems unmounted,
306 * after crash dump done, etc.
307 */
308 void
dohooks(struct hook_desc_head * head,int flags)309 dohooks(struct hook_desc_head *head, int flags)
310 {
311 struct hook_desc *hdp, *hdp_temp;
312
313 if ((flags & HOOK_REMOVE) == 0) {
314 TAILQ_FOREACH_SAFE(hdp, head, hd_list, hdp_temp) {
315 (*hdp->hd_fn)(hdp->hd_arg);
316 }
317 } else {
318 while ((hdp = TAILQ_FIRST(head)) != NULL) {
319 TAILQ_REMOVE(head, hdp, hd_list);
320 (*hdp->hd_fn)(hdp->hd_arg);
321 if ((flags & HOOK_FREE) != 0)
322 free(hdp, M_DEVBUF, sizeof(*hdp));
323 }
324 }
325 }
326