Annotation of sys/kern/kern_subr.c, Revision 1.1
1.1 ! nbrk 1: /* $OpenBSD: kern_subr.c,v 1.31 2007/05/16 17:27:30 art 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 <sys/kernel.h>
! 47: #include <sys/resourcevar.h>
! 48:
! 49: int
! 50: uiomove(void *cp, int n, struct uio *uio)
! 51: {
! 52: struct iovec *iov;
! 53: u_int cnt;
! 54: int error = 0;
! 55: struct proc *p;
! 56:
! 57: p = uio->uio_procp;
! 58:
! 59: #ifdef DIAGNOSTIC
! 60: if (uio->uio_rw != UIO_READ && uio->uio_rw != UIO_WRITE)
! 61: panic("uiomove: mode");
! 62: if (uio->uio_segflg == UIO_USERSPACE && p != curproc)
! 63: panic("uiomove: proc");
! 64: #endif
! 65: while (n > 0 && uio->uio_resid) {
! 66: iov = uio->uio_iov;
! 67: cnt = iov->iov_len;
! 68: if (cnt == 0) {
! 69: uio->uio_iov++;
! 70: uio->uio_iovcnt--;
! 71: continue;
! 72: }
! 73: if (cnt > n)
! 74: cnt = n;
! 75: switch (uio->uio_segflg) {
! 76:
! 77: case UIO_USERSPACE:
! 78: if (curcpu()->ci_schedstate.spc_schedflags &
! 79: SPCF_SHOULDYIELD)
! 80: preempt(NULL);
! 81: if (uio->uio_rw == UIO_READ)
! 82: error = copyout(cp, iov->iov_base, cnt);
! 83: else
! 84: error = copyin(iov->iov_base, cp, cnt);
! 85: if (error)
! 86: return (error);
! 87: break;
! 88:
! 89: case UIO_SYSSPACE:
! 90: if (uio->uio_rw == UIO_READ)
! 91: error = kcopy(cp, iov->iov_base, cnt);
! 92: else
! 93: error = kcopy(iov->iov_base, cp, cnt);
! 94: if (error)
! 95: return(error);
! 96: }
! 97: iov->iov_base = (caddr_t)iov->iov_base + cnt;
! 98: iov->iov_len -= cnt;
! 99: uio->uio_resid -= cnt;
! 100: uio->uio_offset += cnt;
! 101: cp = (caddr_t)cp + cnt;
! 102: n -= cnt;
! 103: }
! 104: return (error);
! 105: }
! 106:
! 107: /*
! 108: * Give next character to user as result of read.
! 109: */
! 110: int
! 111: ureadc(int c, struct uio *uio)
! 112: {
! 113: struct iovec *iov;
! 114:
! 115: if (uio->uio_resid == 0)
! 116: #ifdef DIAGNOSTIC
! 117: panic("ureadc: zero resid");
! 118: #else
! 119: return (EINVAL);
! 120: #endif
! 121: again:
! 122: if (uio->uio_iovcnt <= 0)
! 123: #ifdef DIAGNOSTIC
! 124: panic("ureadc: non-positive iovcnt");
! 125: #else
! 126: return (EINVAL);
! 127: #endif
! 128: iov = uio->uio_iov;
! 129: if (iov->iov_len <= 0) {
! 130: uio->uio_iovcnt--;
! 131: uio->uio_iov++;
! 132: goto again;
! 133: }
! 134: switch (uio->uio_segflg) {
! 135:
! 136: case UIO_USERSPACE:
! 137: {
! 138: char tmp = c;
! 139:
! 140: if (copyout(&tmp, iov->iov_base, sizeof(char)) != 0)
! 141: return (EFAULT);
! 142: }
! 143: break;
! 144:
! 145: case UIO_SYSSPACE:
! 146: *(char *)iov->iov_base = c;
! 147: break;
! 148: }
! 149: iov->iov_base = (caddr_t)iov->iov_base + 1;
! 150: iov->iov_len--;
! 151: uio->uio_resid--;
! 152: uio->uio_offset++;
! 153: return (0);
! 154: }
! 155:
! 156: /*
! 157: * General routine to allocate a hash table.
! 158: */
! 159: void *
! 160: hashinit(int elements, int type, int flags, u_long *hashmask)
! 161: {
! 162: u_long hashsize, i;
! 163: LIST_HEAD(generic, generic) *hashtbl;
! 164:
! 165: if (elements <= 0)
! 166: panic("hashinit: bad cnt");
! 167: for (hashsize = 1; hashsize < elements; hashsize <<= 1)
! 168: continue;
! 169: hashtbl = malloc(hashsize * sizeof(*hashtbl), type, flags);
! 170: if (hashtbl == NULL)
! 171: return NULL;
! 172: for (i = 0; i < hashsize; i++)
! 173: LIST_INIT(&hashtbl[i]);
! 174: *hashmask = hashsize - 1;
! 175: return (hashtbl);
! 176: }
! 177:
! 178: /*
! 179: * "Shutdown/startup hook" types, functions, and variables.
! 180: */
! 181:
! 182: struct hook_desc_head startuphook_list =
! 183: TAILQ_HEAD_INITIALIZER(startuphook_list);
! 184: struct hook_desc_head shutdownhook_list =
! 185: TAILQ_HEAD_INITIALIZER(shutdownhook_list);
! 186: struct hook_desc_head mountroothook_list =
! 187: TAILQ_HEAD_INITIALIZER(mountroothook_list);
! 188:
! 189: void *
! 190: hook_establish(struct hook_desc_head *head, int tail, void (*fn)(void *),
! 191: void *arg)
! 192: {
! 193: struct hook_desc *hdp;
! 194:
! 195: hdp = (struct hook_desc *)malloc(sizeof (*hdp), M_DEVBUF, M_NOWAIT);
! 196: if (hdp == NULL)
! 197: return (NULL);
! 198:
! 199: hdp->hd_fn = fn;
! 200: hdp->hd_arg = arg;
! 201: if (tail)
! 202: TAILQ_INSERT_TAIL(head, hdp, hd_list);
! 203: else
! 204: TAILQ_INSERT_HEAD(head, hdp, hd_list);
! 205:
! 206: return (hdp);
! 207: }
! 208:
! 209: void
! 210: hook_disestablish(struct hook_desc_head *head, void *vhook)
! 211: {
! 212: struct hook_desc *hdp;
! 213:
! 214: #ifdef DIAGNOSTIC
! 215: for (hdp = TAILQ_FIRST(head); hdp != NULL;
! 216: hdp = TAILQ_NEXT(hdp, hd_list))
! 217: if (hdp == vhook)
! 218: break;
! 219: if (hdp == NULL)
! 220: panic("hook_disestablish: hook not established");
! 221: #endif
! 222: hdp = vhook;
! 223: TAILQ_REMOVE(head, hdp, hd_list);
! 224: free(hdp, M_DEVBUF);
! 225: }
! 226:
! 227: /*
! 228: * Run hooks. Startup hooks are invoked right after scheduler_start but
! 229: * before root is mounted. Shutdown hooks are invoked immediately before the
! 230: * system is halted or rebooted, i.e. after file systems unmounted,
! 231: * after crash dump done, etc.
! 232: */
! 233: void
! 234: dohooks(struct hook_desc_head *head, int flags)
! 235: {
! 236: struct hook_desc *hdp;
! 237:
! 238: if ((flags & HOOK_REMOVE) == 0) {
! 239: TAILQ_FOREACH(hdp, head, hd_list) {
! 240: (*hdp->hd_fn)(hdp->hd_arg);
! 241: }
! 242: } else {
! 243: while ((hdp = TAILQ_FIRST(head)) != NULL) {
! 244: TAILQ_REMOVE(head, hdp, hd_list);
! 245: (*hdp->hd_fn)(hdp->hd_arg);
! 246: if ((flags & HOOK_FREE) != 0)
! 247: free(hdp, M_DEVBUF);
! 248: }
! 249: }
! 250: }
! 251:
! 252: /*
! 253: * "Power hook" types, functions, and variables.
! 254: */
! 255:
! 256: struct powerhook_desc {
! 257: CIRCLEQ_ENTRY(powerhook_desc) sfd_list;
! 258: void (*sfd_fn)(int, void *);
! 259: void *sfd_arg;
! 260: };
! 261:
! 262: CIRCLEQ_HEAD(, powerhook_desc) powerhook_list =
! 263: CIRCLEQ_HEAD_INITIALIZER(powerhook_list);
! 264:
! 265: void *
! 266: powerhook_establish(void (*fn)(int, void *), void *arg)
! 267: {
! 268: struct powerhook_desc *ndp;
! 269:
! 270: ndp = (struct powerhook_desc *)
! 271: malloc(sizeof(*ndp), M_DEVBUF, M_NOWAIT);
! 272: if (ndp == NULL)
! 273: return NULL;
! 274:
! 275: ndp->sfd_fn = fn;
! 276: ndp->sfd_arg = arg;
! 277: CIRCLEQ_INSERT_HEAD(&powerhook_list, ndp, sfd_list);
! 278:
! 279: return (ndp);
! 280: }
! 281:
! 282: void
! 283: powerhook_disestablish(void *vhook)
! 284: {
! 285: #ifdef DIAGNOSTIC
! 286: struct powerhook_desc *dp;
! 287:
! 288: CIRCLEQ_FOREACH(dp, &powerhook_list, sfd_list)
! 289: if (dp == vhook)
! 290: break;
! 291: if (dp == NULL)
! 292: panic("powerhook_disestablish: hook not established");
! 293: #endif
! 294:
! 295: CIRCLEQ_REMOVE(&powerhook_list, (struct powerhook_desc *)vhook,
! 296: sfd_list);
! 297: free(vhook, M_DEVBUF);
! 298: }
! 299:
! 300: /*
! 301: * Run power hooks.
! 302: */
! 303: void
! 304: dopowerhooks(int why)
! 305: {
! 306: struct powerhook_desc *dp;
! 307: int s;
! 308:
! 309: s = splhigh();
! 310: if (why == PWR_RESUME) {
! 311: CIRCLEQ_FOREACH_REVERSE(dp, &powerhook_list, sfd_list) {
! 312: (*dp->sfd_fn)(why, dp->sfd_arg);
! 313: }
! 314: } else {
! 315: CIRCLEQ_FOREACH(dp, &powerhook_list, sfd_list) {
! 316: (*dp->sfd_fn)(why, dp->sfd_arg);
! 317: }
! 318: }
! 319: splx(s);
! 320: }
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