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src/sys/kern/kern_subr.c

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/* $OpenBSD: kern_subr.c,v 1.52 2023/01/31 15:18:56 deraadt Exp $ */
/* $NetBSD: kern_subr.c,v 1.15 1996/04/09 17:21:56 ragge Exp $ */
/*
* Copyright (c) 1982, 1986, 1991, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)kern_subr.c 8.3 (Berkeley) 1/21/94
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/sched.h>
#include <sys/malloc.h>
#include <sys/queue.h>
#include <uvm/uvm_extern.h>
#ifdef PMAP_CHECK_COPYIN
static inline int check_copyin(struct proc *, const void *, size_t);
extern int _copyinstr(const void *, void *, size_t, size_t *);
extern int _copyin(const void *uaddr, void *kaddr, size_t len);
/*
* If range overlaps an check_copyin region, return EFAULT
*/
static inline int
check_copyin(struct proc *p, const void *vstart, size_t len)
{
struct vm_map *map = &p->p_vmspace->vm_map;
const vaddr_t start = (vaddr_t)vstart;
const vaddr_t end = start + len;
int i, max;
/* XXX if the array was sorted, we could shortcut */
max = map->check_copyin_count;
membar_consumer();
for (i = 0; i < max; i++) {
vaddr_t s = map->check_copyin[i].start;
vaddr_t e = map->check_copyin[i].end;
if ((start >= s && start < e) || (end > s && end < e))
return EFAULT;
}
return (0);
}
int
copyinstr(const void *uaddr, void *kaddr, size_t len, size_t *done)
{
size_t alen;
int error;
/*
* Must do the copyin checks after figuring out the string length,
* the buffer size length may cross into another ELF segment
*/
error = _copyinstr(uaddr, kaddr, len, &alen);
if (PMAP_CHECK_COPYIN && error == 0)
error = check_copyin(curproc, uaddr, alen);
if (done)
*done = alen;
return (error);
}
int
copyin(const void *uaddr, void *kaddr, size_t len)
{
int error = 0;
if (PMAP_CHECK_COPYIN)
error = check_copyin(curproc, uaddr, len);
if (error == 0)
error = _copyin(uaddr, kaddr, len);
return (error);
}
#endif /* PMAP_CHECK_COPYIN */
int
uiomove(void *cp, size_t n, struct uio *uio)
{
struct iovec *iov;
size_t cnt;
int error = 0;
#ifdef DIAGNOSTIC
if (uio->uio_rw != UIO_READ && uio->uio_rw != UIO_WRITE)
panic("uiomove: mode");
if (uio->uio_segflg == UIO_USERSPACE && uio->uio_procp != curproc)
panic("uiomove: proc");
#endif
if (n > uio->uio_resid)
n = uio->uio_resid;
while (n > 0) {
iov = uio->uio_iov;
cnt = iov->iov_len;
if (cnt == 0) {
KASSERT(uio->uio_iovcnt > 0);
uio->uio_iov++;
uio->uio_iovcnt--;
continue;
}
if (cnt > n)
cnt = n;
switch (uio->uio_segflg) {
case UIO_USERSPACE:
sched_pause(preempt);
if (uio->uio_rw == UIO_READ)
error = copyout(cp, iov->iov_base, cnt);
else
error = copyin(iov->iov_base, cp, cnt);
if (error)
return (error);
break;
case UIO_SYSSPACE:
if (uio->uio_rw == UIO_READ)
error = kcopy(cp, iov->iov_base, cnt);
else
error = kcopy(iov->iov_base, cp, cnt);
if (error)
return(error);
}
iov->iov_base = (caddr_t)iov->iov_base + cnt;
iov->iov_len -= cnt;
uio->uio_resid -= cnt;
uio->uio_offset += cnt;
cp = (caddr_t)cp + cnt;
n -= cnt;
}
return (error);
}
/*
* Give next character to user as result of read.
*/
int
ureadc(int c, struct uio *uio)
{
struct iovec *iov;
if (uio->uio_resid == 0)
#ifdef DIAGNOSTIC
panic("ureadc: zero resid");
#else
return (EINVAL);
#endif
again:
if (uio->uio_iovcnt <= 0)
#ifdef DIAGNOSTIC
panic("ureadc: non-positive iovcnt");
#else
return (EINVAL);
#endif
iov = uio->uio_iov;
if (iov->iov_len <= 0) {
uio->uio_iovcnt--;
uio->uio_iov++;
goto again;
}
switch (uio->uio_segflg) {
case UIO_USERSPACE:
{
char tmp = c;
if (copyout(&tmp, iov->iov_base, sizeof(char)) != 0)
return (EFAULT);
}
break;
case UIO_SYSSPACE:
*(char *)iov->iov_base = c;
break;
}
iov->iov_base = (caddr_t)iov->iov_base + 1;
iov->iov_len--;
uio->uio_resid--;
uio->uio_offset++;
return (0);
}
/*
* General routine to allocate a hash table.
*/
void *
hashinit(int elements, int type, int flags, u_long *hashmask)
{
u_long hashsize, i;
LIST_HEAD(generic, generic) *hashtbl;
if (elements <= 0)
panic("hashinit: bad cnt");
if ((elements & (elements - 1)) == 0)
hashsize = elements;
else
for (hashsize = 1; hashsize < elements; hashsize <<= 1)
continue;
hashtbl = mallocarray(hashsize, sizeof(*hashtbl), type, flags);
if (hashtbl == NULL)
return NULL;
for (i = 0; i < hashsize; i++)
LIST_INIT(&hashtbl[i]);
*hashmask = hashsize - 1;
return (hashtbl);
}
void
hashfree(void *hash, int elements, int type)
{
u_long hashsize;
LIST_HEAD(generic, generic) *hashtbl = hash;
if (elements <= 0)
panic("hashfree: bad cnt");
if ((elements & (elements - 1)) == 0)
hashsize = elements;
else
for (hashsize = 1; hashsize < elements; hashsize <<= 1)
continue;
free(hashtbl, type, sizeof(*hashtbl) * hashsize);
}
/*
* "startup hook" types, functions, and variables.
*/
struct hook_desc_head startuphook_list =
TAILQ_HEAD_INITIALIZER(startuphook_list);
void *
hook_establish(struct hook_desc_head *head, int tail, void (*fn)(void *),
void *arg)
{
struct hook_desc *hdp;
hdp = malloc(sizeof(*hdp), M_DEVBUF, M_NOWAIT);
if (hdp == NULL)
return (NULL);
hdp->hd_fn = fn;
hdp->hd_arg = arg;
if (tail)
TAILQ_INSERT_TAIL(head, hdp, hd_list);
else
TAILQ_INSERT_HEAD(head, hdp, hd_list);
return (hdp);
}
void
hook_disestablish(struct hook_desc_head *head, void *vhook)
{
struct hook_desc *hdp;
#ifdef DIAGNOSTIC
for (hdp = TAILQ_FIRST(head); hdp != NULL;
hdp = TAILQ_NEXT(hdp, hd_list))
if (hdp == vhook)
break;
if (hdp == NULL)
return;
#endif
hdp = vhook;
TAILQ_REMOVE(head, hdp, hd_list);
free(hdp, M_DEVBUF, sizeof(*hdp));
}
/*
* Run hooks. Startup hooks are invoked right after scheduler_start but
* before root is mounted. Shutdown hooks are invoked immediately before the
* system is halted or rebooted, i.e. after file systems unmounted,
* after crash dump done, etc.
*/
void
dohooks(struct hook_desc_head *head, int flags)
{
struct hook_desc *hdp, *hdp_temp;
if ((flags & HOOK_REMOVE) == 0) {
TAILQ_FOREACH_SAFE(hdp, head, hd_list, hdp_temp) {
(*hdp->hd_fn)(hdp->hd_arg);
}
} else {
while ((hdp = TAILQ_FIRST(head)) != NULL) {
TAILQ_REMOVE(head, hdp, hd_list);
(*hdp->hd_fn)(hdp->hd_arg);
if ((flags & HOOK_FREE) != 0)
free(hdp, M_DEVBUF, sizeof(*hdp));
}
}
}
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