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freebsd/sys/kern/kern_sysctl.c

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/*-
* Copyright (c) 1982, 1986, 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Mike Karels at Berkeley Software Design, Inc.
*
* Quite extensively rewritten by Poul-Henning Kamp of the FreeBSD
* project, to make these variables more userfriendly.
*
* 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.
* 4. 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_sysctl.c 8.4 (Berkeley) 4/14/94
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_capsicum.h"
#include "opt_compat.h"
#include "opt_ktrace.h"
#include <sys/param.h>
#include <sys/fail.h>
#include <sys/systm.h>
#include <sys/capsicum.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>
#include <sys/malloc.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/jail.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/sbuf.h>
#include <sys/sx.h>
#include <sys/sysproto.h>
#include <sys/uio.h>
#ifdef KTRACE
#include <sys/ktrace.h>
#endif
#include <net/vnet.h>
#include <security/mac/mac_framework.h>
#include <vm/vm.h>
#include <vm/vm_extern.h>
static MALLOC_DEFINE(M_SYSCTL, "sysctl", "sysctl internal magic");
static MALLOC_DEFINE(M_SYSCTLOID, "sysctloid", "sysctl dynamic oids");
static MALLOC_DEFINE(M_SYSCTLTMP, "sysctltmp", "sysctl temp output buffer");
/*
* The sysctllock protects the MIB tree. It also protects sysctl
* contexts used with dynamic sysctls. The sysctl_register_oid() and
* sysctl_unregister_oid() routines require the sysctllock to already
* be held, so the sysctl_lock() and sysctl_unlock() routines are
* provided for the few places in the kernel which need to use that
* API rather than using the dynamic API. Use of the dynamic API is
* strongly encouraged for most code.
*
* The sysctlmemlock is used to limit the amount of user memory wired for
* sysctl requests. This is implemented by serializing any userland
* sysctl requests larger than a single page via an exclusive lock.
*/
static struct sx sysctllock;
static struct sx sysctlmemlock;
#define SYSCTL_XLOCK() sx_xlock(&sysctllock)
#define SYSCTL_XUNLOCK() sx_xunlock(&sysctllock)
#define SYSCTL_ASSERT_XLOCKED() sx_assert(&sysctllock, SA_XLOCKED)
#define SYSCTL_INIT() sx_init(&sysctllock, "sysctl lock")
#define SYSCTL_SLEEP(ch, wmesg, timo) \
sx_sleep(ch, &sysctllock, 0, wmesg, timo)
static int sysctl_root(SYSCTL_HANDLER_ARGS);
/* Root list */
struct sysctl_oid_list sysctl__children = SLIST_HEAD_INITIALIZER(&sysctl__children);
static int sysctl_remove_oid_locked(struct sysctl_oid *oidp, int del,
int recurse);
static int sysctl_old_kernel(struct sysctl_req *, const void *, size_t);
static int sysctl_new_kernel(struct sysctl_req *, void *, size_t);
static struct sysctl_oid *
sysctl_find_oidname(const char *name, struct sysctl_oid_list *list)
{
struct sysctl_oid *oidp;
SYSCTL_ASSERT_XLOCKED();
SLIST_FOREACH(oidp, list, oid_link) {
if (strcmp(oidp->oid_name, name) == 0) {
return (oidp);
}
}
return (NULL);
}
/*
* Initialization of the MIB tree.
*
* Order by number in each list.
*/
void
sysctl_lock(void)
{
SYSCTL_XLOCK();
}
void
sysctl_unlock(void)
{
SYSCTL_XUNLOCK();
}
static int
sysctl_root_handler_locked(struct sysctl_oid *oid, void *arg1, intptr_t arg2,
struct sysctl_req *req)
{
int error;
oid->oid_running++;
SYSCTL_XUNLOCK();
if (!(oid->oid_kind & CTLFLAG_MPSAFE))
mtx_lock(&Giant);
error = oid->oid_handler(oid, arg1, arg2, req);
if (!(oid->oid_kind & CTLFLAG_MPSAFE))
mtx_unlock(&Giant);
SYSCTL_XLOCK();
oid->oid_running--;
if (oid->oid_running == 0 && (oid->oid_kind & CTLFLAG_DYING) != 0)
wakeup(&oid->oid_running);
return (error);
}
static void
sysctl_load_tunable_by_oid_locked(struct sysctl_oid *oidp)
{
struct sysctl_req req;
struct sysctl_oid *curr;
char *penv = NULL;
char path[64];
ssize_t rem = sizeof(path);
ssize_t len;
int val_int;
long val_long;
int64_t val_64;
quad_t val_quad;
int error;
path[--rem] = 0;
for (curr = oidp; curr != NULL; curr = SYSCTL_PARENT(curr)) {
len = strlen(curr->oid_name);
rem -= len;
if (curr != oidp)
rem -= 1;
if (rem < 0) {
printf("OID path exceeds %d bytes\n", (int)sizeof(path));
return;
}
memcpy(path + rem, curr->oid_name, len);
if (curr != oidp)
path[rem + len] = '.';
}
memset(&req, 0, sizeof(req));
req.td = curthread;
req.oldfunc = sysctl_old_kernel;
req.newfunc = sysctl_new_kernel;
req.lock = REQ_UNWIRED;
switch (oidp->oid_kind & CTLTYPE) {
case CTLTYPE_INT:
if (getenv_int(path + rem, &val_int) == 0)
return;
req.newlen = sizeof(val_int);
req.newptr = &val_int;
break;
case CTLTYPE_UINT:
if (getenv_uint(path + rem, (unsigned int *)&val_int) == 0)
return;
req.newlen = sizeof(val_int);
req.newptr = &val_int;
break;
case CTLTYPE_LONG:
if (getenv_long(path + rem, &val_long) == 0)
return;
req.newlen = sizeof(val_long);
req.newptr = &val_long;
break;
case CTLTYPE_ULONG:
if (getenv_ulong(path + rem, (unsigned long *)&val_long) == 0)
return;
req.newlen = sizeof(val_long);
req.newptr = &val_long;
break;
case CTLTYPE_S64:
if (getenv_quad(path + rem, &val_quad) == 0)
return;
val_64 = val_quad;
req.newlen = sizeof(val_64);
req.newptr = &val_64;
break;
case CTLTYPE_U64:
/* XXX there is no getenv_uquad() */
if (getenv_quad(path + rem, &val_quad) == 0)
return;
val_64 = val_quad;
req.newlen = sizeof(val_64);
req.newptr = &val_64;
break;
case CTLTYPE_STRING:
penv = getenv(path + rem);
if (penv == NULL)
return;
req.newlen = strlen(penv);
req.newptr = penv;
break;
default:
return;
}
error = sysctl_root_handler_locked(oidp, oidp->oid_arg1,
oidp->oid_arg2, &req);
if (error != 0) {
printf("Setting sysctl '%s' to '%s' failed: %d\n",
path, penv, error);
}
freeenv(penv);
}
void
sysctl_register_oid(struct sysctl_oid *oidp)
{
struct sysctl_oid_list *parent = oidp->oid_parent;
struct sysctl_oid *p;
struct sysctl_oid *q;
/*
* First check if another oid with the same name already
* exists in the parent's list.
*/
SYSCTL_ASSERT_XLOCKED();
p = sysctl_find_oidname(oidp->oid_name, parent);
if (p != NULL) {
if ((p->oid_kind & CTLTYPE) == CTLTYPE_NODE) {
p->oid_refcnt++;
return;
} else {
printf("can't re-use a leaf (%s)!\n", p->oid_name);
return;
}
}
/*
* If this oid has a number OID_AUTO, give it a number which
* is greater than any current oid.
* NOTE: DO NOT change the starting value here, change it in
* <sys/sysctl.h>, and make sure it is at least 256 to
* accomodate e.g. net.inet.raw as a static sysctl node.
*/
if (oidp->oid_number == OID_AUTO) {
static int newoid = CTL_AUTO_START;
oidp->oid_number = newoid++;
if (newoid == 0x7fffffff)
panic("out of oids");
}
#if 0
else if (oidp->oid_number >= CTL_AUTO_START) {
/* do not panic; this happens when unregistering sysctl sets */
printf("static sysctl oid too high: %d", oidp->oid_number);
}
#endif
/*
* Insert the oid into the parent's list in order.
*/
q = NULL;
SLIST_FOREACH(p, parent, oid_link) {
if (oidp->oid_number < p->oid_number)
break;
q = p;
}
if (q)
SLIST_INSERT_AFTER(q, oidp, oid_link);
else
SLIST_INSERT_HEAD(parent, oidp, oid_link);
if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE &&
#ifdef VIMAGE
(oidp->oid_kind & CTLFLAG_VNET) == 0 &&
#endif
(oidp->oid_kind & CTLFLAG_TUN) != 0 &&
(oidp->oid_kind & CTLFLAG_NOFETCH) == 0) {
sysctl_load_tunable_by_oid_locked(oidp);
}
}
void
sysctl_unregister_oid(struct sysctl_oid *oidp)
{
struct sysctl_oid *p;
int error;
SYSCTL_ASSERT_XLOCKED();
error = ENOENT;
if (oidp->oid_number == OID_AUTO) {
error = EINVAL;
} else {
SLIST_FOREACH(p, oidp->oid_parent, oid_link) {
if (p == oidp) {
SLIST_REMOVE(oidp->oid_parent, oidp,
sysctl_oid, oid_link);
error = 0;
break;
}
}
}
/*
* This can happen when a module fails to register and is
* being unloaded afterwards. It should not be a panic()
* for normal use.
*/
if (error)
printf("%s: failed to unregister sysctl\n", __func__);
}
/* Initialize a new context to keep track of dynamically added sysctls. */
int
sysctl_ctx_init(struct sysctl_ctx_list *c)
{
if (c == NULL) {
return (EINVAL);
}
/*
* No locking here, the caller is responsible for not adding
* new nodes to a context until after this function has
* returned.
*/
TAILQ_INIT(c);
return (0);
}
/* Free the context, and destroy all dynamic oids registered in this context */
int
sysctl_ctx_free(struct sysctl_ctx_list *clist)
{
struct sysctl_ctx_entry *e, *e1;
int error;
error = 0;
/*
* First perform a "dry run" to check if it's ok to remove oids.
* XXX FIXME
* XXX This algorithm is a hack. But I don't know any
* XXX better solution for now...
*/
SYSCTL_XLOCK();
TAILQ_FOREACH(e, clist, link) {
error = sysctl_remove_oid_locked(e->entry, 0, 0);
if (error)
break;
}
/*
* Restore deregistered entries, either from the end,
* or from the place where error occured.
* e contains the entry that was not unregistered
*/
if (error)
e1 = TAILQ_PREV(e, sysctl_ctx_list, link);
else
e1 = TAILQ_LAST(clist, sysctl_ctx_list);
while (e1 != NULL) {
sysctl_register_oid(e1->entry);
e1 = TAILQ_PREV(e1, sysctl_ctx_list, link);
}
if (error) {
SYSCTL_XUNLOCK();
return(EBUSY);
}
/* Now really delete the entries */
e = TAILQ_FIRST(clist);
while (e != NULL) {
e1 = TAILQ_NEXT(e, link);
error = sysctl_remove_oid_locked(e->entry, 1, 0);
if (error)
panic("sysctl_remove_oid: corrupt tree, entry: %s",
e->entry->oid_name);
free(e, M_SYSCTLOID);
e = e1;
}
SYSCTL_XUNLOCK();
return (error);
}
/* Add an entry to the context */
struct sysctl_ctx_entry *
sysctl_ctx_entry_add(struct sysctl_ctx_list *clist, struct sysctl_oid *oidp)
{
struct sysctl_ctx_entry *e;
SYSCTL_ASSERT_XLOCKED();
if (clist == NULL || oidp == NULL)
return(NULL);
e = malloc(sizeof(struct sysctl_ctx_entry), M_SYSCTLOID, M_WAITOK);
e->entry = oidp;
TAILQ_INSERT_HEAD(clist, e, link);
return (e);
}
/* Find an entry in the context */
struct sysctl_ctx_entry *
sysctl_ctx_entry_find(struct sysctl_ctx_list *clist, struct sysctl_oid *oidp)
{
struct sysctl_ctx_entry *e;
SYSCTL_ASSERT_XLOCKED();
if (clist == NULL || oidp == NULL)
return(NULL);
TAILQ_FOREACH(e, clist, link) {
if(e->entry == oidp)
return(e);
}
return (e);
}
/*
* Delete an entry from the context.
* NOTE: this function doesn't free oidp! You have to remove it
* with sysctl_remove_oid().
*/
int
sysctl_ctx_entry_del(struct sysctl_ctx_list *clist, struct sysctl_oid *oidp)
{
struct sysctl_ctx_entry *e;
if (clist == NULL || oidp == NULL)
return (EINVAL);
SYSCTL_XLOCK();
e = sysctl_ctx_entry_find(clist, oidp);
if (e != NULL) {
TAILQ_REMOVE(clist, e, link);
SYSCTL_XUNLOCK();
free(e, M_SYSCTLOID);
return (0);
} else {
SYSCTL_XUNLOCK();
return (ENOENT);
}
}
/*
* Remove dynamically created sysctl trees.
* oidp - top of the tree to be removed
* del - if 0 - just deregister, otherwise free up entries as well
* recurse - if != 0 traverse the subtree to be deleted
*/
int
sysctl_remove_oid(struct sysctl_oid *oidp, int del, int recurse)
{
int error;
SYSCTL_XLOCK();
error = sysctl_remove_oid_locked(oidp, del, recurse);
SYSCTL_XUNLOCK();
return (error);
}
int
sysctl_remove_name(struct sysctl_oid *parent, const char *name,
int del, int recurse)
{
struct sysctl_oid *p, *tmp;
int error;
error = ENOENT;
SYSCTL_XLOCK();
SLIST_FOREACH_SAFE(p, SYSCTL_CHILDREN(parent), oid_link, tmp) {
if (strcmp(p->oid_name, name) == 0) {
error = sysctl_remove_oid_locked(p, del, recurse);
break;
}
}
SYSCTL_XUNLOCK();
return (error);
}
static int
sysctl_remove_oid_locked(struct sysctl_oid *oidp, int del, int recurse)
{
struct sysctl_oid *p, *tmp;
int error;
SYSCTL_ASSERT_XLOCKED();
if (oidp == NULL)
return(EINVAL);
if ((oidp->oid_kind & CTLFLAG_DYN) == 0) {
printf("can't remove non-dynamic nodes!\n");
return (EINVAL);
}
/*
* WARNING: normal method to do this should be through
* sysctl_ctx_free(). Use recursing as the last resort
* method to purge your sysctl tree of leftovers...
* However, if some other code still references these nodes,
* it will panic.
*/
if ((oidp->oid_kind & CTLTYPE) == CTLTYPE_NODE) {
if (oidp->oid_refcnt == 1) {
SLIST_FOREACH_SAFE(p,
SYSCTL_CHILDREN(oidp), oid_link, tmp) {
if (!recurse) {
printf("Warning: failed attempt to "
"remove oid %s with child %s\n",
oidp->oid_name, p->oid_name);
return (ENOTEMPTY);
}
error = sysctl_remove_oid_locked(p, del,
recurse);
if (error)
return (error);
}
}
}
if (oidp->oid_refcnt > 1 ) {
oidp->oid_refcnt--;
} else {
if (oidp->oid_refcnt == 0) {
printf("Warning: bad oid_refcnt=%u (%s)!\n",
oidp->oid_refcnt, oidp->oid_name);
return (EINVAL);
}
sysctl_unregister_oid(oidp);
if (del) {
/*
* Wait for all threads running the handler to drain.
* This preserves the previous behavior when the
* sysctl lock was held across a handler invocation,
* and is necessary for module unload correctness.
*/
while (oidp->oid_running > 0) {
oidp->oid_kind |= CTLFLAG_DYING;
SYSCTL_SLEEP(&oidp->oid_running, "oidrm", 0);
}
if (oidp->oid_descr)
free(__DECONST(char *, oidp->oid_descr),
M_SYSCTLOID);
free(__DECONST(char *, oidp->oid_name), M_SYSCTLOID);
free(oidp, M_SYSCTLOID);
}
}
return (0);
}
/*
* Create new sysctls at run time.
* clist may point to a valid context initialized with sysctl_ctx_init().
*/
struct sysctl_oid *
sysctl_add_oid(struct sysctl_ctx_list *clist, struct sysctl_oid_list *parent,
int number, const char *name, int kind, void *arg1, intptr_t arg2,
int (*handler)(SYSCTL_HANDLER_ARGS), const char *fmt, const char *descr)
{
struct sysctl_oid *oidp;
/* You have to hook up somewhere.. */
if (parent == NULL)
return(NULL);
/* Check if the node already exists, otherwise create it */
SYSCTL_XLOCK();
oidp = sysctl_find_oidname(name, parent);
if (oidp != NULL) {
if ((oidp->oid_kind & CTLTYPE) == CTLTYPE_NODE) {
oidp->oid_refcnt++;
/* Update the context */
if (clist != NULL)
sysctl_ctx_entry_add(clist, oidp);
SYSCTL_XUNLOCK();
return (oidp);
} else {
SYSCTL_XUNLOCK();
printf("can't re-use a leaf (%s)!\n", name);
return (NULL);
}
}
oidp = malloc(sizeof(struct sysctl_oid), M_SYSCTLOID, M_WAITOK|M_ZERO);
oidp->oid_parent = parent;
SLIST_INIT(&oidp->oid_children);
oidp->oid_number = number;
oidp->oid_refcnt = 1;
oidp->oid_name = strdup(name, M_SYSCTLOID);
oidp->oid_handler = handler;
oidp->oid_kind = CTLFLAG_DYN | kind;
oidp->oid_arg1 = arg1;
oidp->oid_arg2 = arg2;
oidp->oid_fmt = fmt;
if (descr != NULL)
oidp->oid_descr = strdup(descr, M_SYSCTLOID);
/* Update the context, if used */
if (clist != NULL)
sysctl_ctx_entry_add(clist, oidp);
/* Register this oid */
sysctl_register_oid(oidp);
SYSCTL_XUNLOCK();
return (oidp);
}
/*
* Rename an existing oid.
*/
void
sysctl_rename_oid(struct sysctl_oid *oidp, const char *name)
{
char *newname;
char *oldname;
newname = strdup(name, M_SYSCTLOID);
SYSCTL_XLOCK();
oldname = __DECONST(char *, oidp->oid_name);
oidp->oid_name = newname;
SYSCTL_XUNLOCK();
free(oldname, M_SYSCTLOID);
}
/*
* Reparent an existing oid.
*/
int
sysctl_move_oid(struct sysctl_oid *oid, struct sysctl_oid_list *parent)
{
struct sysctl_oid *oidp;
SYSCTL_XLOCK();
if (oid->oid_parent == parent) {
SYSCTL_XUNLOCK();
return (0);
}
oidp = sysctl_find_oidname(oid->oid_name, parent);
if (oidp != NULL) {
SYSCTL_XUNLOCK();
return (EEXIST);
}
sysctl_unregister_oid(oid);
oid->oid_parent = parent;
oid->oid_number = OID_AUTO;
sysctl_register_oid(oid);
SYSCTL_XUNLOCK();
return (0);
}
/*
* Register the kernel's oids on startup.
*/
SET_DECLARE(sysctl_set, struct sysctl_oid);
static void
sysctl_register_all(void *arg)
{
struct sysctl_oid **oidp;
sx_init(&sysctlmemlock, "sysctl mem");
SYSCTL_INIT();
SYSCTL_XLOCK();
SET_FOREACH(oidp, sysctl_set)
sysctl_register_oid(*oidp);
SYSCTL_XUNLOCK();
}
SYSINIT(sysctl, SI_SUB_KMEM, SI_ORDER_FIRST, sysctl_register_all, 0);
/*
* "Staff-functions"
*
* These functions implement a presently undocumented interface
* used by the sysctl program to walk the tree, and get the type
* so it can print the value.
* This interface is under work and consideration, and should probably
* be killed with a big axe by the first person who can find the time.
* (be aware though, that the proper interface isn't as obvious as it
* may seem, there are various conflicting requirements.
*
* {0,0} printf the entire MIB-tree.
* {0,1,...} return the name of the "..." OID.
* {0,2,...} return the next OID.
* {0,3} return the OID of the name in "new"
* {0,4,...} return the kind & format info for the "..." OID.
* {0,5,...} return the description the "..." OID.
*/
#ifdef SYSCTL_DEBUG
static void
sysctl_sysctl_debug_dump_node(struct sysctl_oid_list *l, int i)
{
int k;
struct sysctl_oid *oidp;
SYSCTL_ASSERT_XLOCKED();
SLIST_FOREACH(oidp, l, oid_link) {
for (k=0; k<i; k++)
printf(" ");
printf("%d %s ", oidp->oid_number, oidp->oid_name);
printf("%c%c",
oidp->oid_kind & CTLFLAG_RD ? 'R':' ',
oidp->oid_kind & CTLFLAG_WR ? 'W':' ');
if (oidp->oid_handler)
printf(" *Handler");
switch (oidp->oid_kind & CTLTYPE) {
case CTLTYPE_NODE:
printf(" Node\n");
if (!oidp->oid_handler) {
sysctl_sysctl_debug_dump_node(
SYSCTL_CHILDREN(oidp), i + 2);
}
break;
case CTLTYPE_INT: printf(" Int\n"); break;
case CTLTYPE_UINT: printf(" u_int\n"); break;
case CTLTYPE_LONG: printf(" Long\n"); break;
case CTLTYPE_ULONG: printf(" u_long\n"); break;
case CTLTYPE_STRING: printf(" String\n"); break;
case CTLTYPE_U64: printf(" uint64_t\n"); break;
case CTLTYPE_S64: printf(" int64_t\n"); break;
case CTLTYPE_OPAQUE: printf(" Opaque/struct\n"); break;
default: printf("\n");
}
}
}
static int
sysctl_sysctl_debug(SYSCTL_HANDLER_ARGS)
{
int error;
error = priv_check(req->td, PRIV_SYSCTL_DEBUG);
if (error)
return (error);
SYSCTL_XLOCK();
sysctl_sysctl_debug_dump_node(&sysctl__children, 0);
SYSCTL_XUNLOCK();
return (ENOENT);
}
SYSCTL_PROC(_sysctl, 0, debug, CTLTYPE_STRING|CTLFLAG_RD,
0, 0, sysctl_sysctl_debug, "-", "");
#endif
static int
sysctl_sysctl_name(SYSCTL_HANDLER_ARGS)
{
int *name = (int *) arg1;
u_int namelen = arg2;
int error = 0;
struct sysctl_oid *oid;
struct sysctl_oid_list *lsp = &sysctl__children, *lsp2;
char buf[10];
SYSCTL_XLOCK();
while (namelen) {
if (!lsp) {
snprintf(buf,sizeof(buf),"%d",*name);
if (req->oldidx)
error = SYSCTL_OUT(req, ".", 1);
if (!error)
error = SYSCTL_OUT(req, buf, strlen(buf));
if (error)
goto out;
namelen--;
name++;
continue;
}
lsp2 = 0;
SLIST_FOREACH(oid, lsp, oid_link) {
if (oid->oid_number != *name)
continue;
if (req->oldidx)
error = SYSCTL_OUT(req, ".", 1);
if (!error)
error = SYSCTL_OUT(req, oid->oid_name,
strlen(oid->oid_name));
if (error)
goto out;
namelen--;
name++;
if ((oid->oid_kind & CTLTYPE) != CTLTYPE_NODE)
break;
if (oid->oid_handler)
break;
lsp2 = SYSCTL_CHILDREN(oid);
break;
}
lsp = lsp2;
}
error = SYSCTL_OUT(req, "", 1);
out:
SYSCTL_XUNLOCK();
return (error);
}
/*
* XXXRW/JA: Shouldn't return name data for nodes that we don't permit in
* capability mode.
*/
static SYSCTL_NODE(_sysctl, 1, name, CTLFLAG_RD | CTLFLAG_CAPRD,
sysctl_sysctl_name, "");
static int
sysctl_sysctl_next_ls(struct sysctl_oid_list *lsp, int *name, u_int namelen,
int *next, int *len, int level, struct sysctl_oid **oidpp)
{
struct sysctl_oid *oidp;
SYSCTL_ASSERT_XLOCKED();
*len = level;
SLIST_FOREACH(oidp, lsp, oid_link) {
*next = oidp->oid_number;
*oidpp = oidp;
if (oidp->oid_kind & CTLFLAG_SKIP)
continue;
if (!namelen) {
if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE)
return (0);
if (oidp->oid_handler)
/* We really should call the handler here...*/
return (0);
lsp = SYSCTL_CHILDREN(oidp);
if (!sysctl_sysctl_next_ls(lsp, 0, 0, next+1,
len, level+1, oidpp))
return (0);
goto emptynode;
}
if (oidp->oid_number < *name)
continue;
if (oidp->oid_number > *name) {
if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE)
return (0);
if (oidp->oid_handler)
return (0);
lsp = SYSCTL_CHILDREN(oidp);
if (!sysctl_sysctl_next_ls(lsp, name+1, namelen-1,
next+1, len, level+1, oidpp))
return (0);
goto next;
}
if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE)
continue;
if (oidp->oid_handler)
continue;
lsp = SYSCTL_CHILDREN(oidp);
if (!sysctl_sysctl_next_ls(lsp, name+1, namelen-1, next+1,
len, level+1, oidpp))
return (0);
next:
namelen = 1;
emptynode:
*len = level;
}
return (1);
}
static int
sysctl_sysctl_next(SYSCTL_HANDLER_ARGS)
{
int *name = (int *) arg1;
u_int namelen = arg2;
int i, j, error;
struct sysctl_oid *oid;
struct sysctl_oid_list *lsp = &sysctl__children;
int newoid[CTL_MAXNAME];
SYSCTL_XLOCK();
i = sysctl_sysctl_next_ls(lsp, name, namelen, newoid, &j, 1, &oid);
SYSCTL_XUNLOCK();
if (i)
return (ENOENT);
error = SYSCTL_OUT(req, newoid, j * sizeof (int));
return (error);
}
/*
* XXXRW/JA: Shouldn't return next data for nodes that we don't permit in
* capability mode.
*/
static SYSCTL_NODE(_sysctl, 2, next, CTLFLAG_RD | CTLFLAG_CAPRD,
sysctl_sysctl_next, "");
static int
name2oid(char *name, int *oid, int *len, struct sysctl_oid **oidpp)
{
struct sysctl_oid *oidp;
struct sysctl_oid_list *lsp = &sysctl__children;
char *p;
SYSCTL_ASSERT_XLOCKED();
for (*len = 0; *len < CTL_MAXNAME;) {
p = strsep(&name, ".");
oidp = SLIST_FIRST(lsp);
for (;; oidp = SLIST_NEXT(oidp, oid_link)) {
if (oidp == NULL)
return (ENOENT);
if (strcmp(p, oidp->oid_name) == 0)
break;
}
*oid++ = oidp->oid_number;
(*len)++;
if (name == NULL || *name == '\0') {
if (oidpp)
*oidpp = oidp;
return (0);
}
if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE)
break;
if (oidp->oid_handler)
break;
lsp = SYSCTL_CHILDREN(oidp);
}
return (ENOENT);
}
static int
sysctl_sysctl_name2oid(SYSCTL_HANDLER_ARGS)
{
char *p;
int error, oid[CTL_MAXNAME], len = 0;
struct sysctl_oid *op = 0;
if (!req->newlen)
return (ENOENT);
if (req->newlen >= MAXPATHLEN) /* XXX arbitrary, undocumented */
return (ENAMETOOLONG);
p = malloc(req->newlen+1, M_SYSCTL, M_WAITOK);
error = SYSCTL_IN(req, p, req->newlen);
if (error) {
free(p, M_SYSCTL);
return (error);
}
p [req->newlen] = '\0';
SYSCTL_XLOCK();
error = name2oid(p, oid, &len, &op);
SYSCTL_XUNLOCK();
free(p, M_SYSCTL);
if (error)
return (error);
error = SYSCTL_OUT(req, oid, len * sizeof *oid);
return (error);
}
/*
* XXXRW/JA: Shouldn't return name2oid data for nodes that we don't permit in
* capability mode.
*/
SYSCTL_PROC(_sysctl, 3, name2oid,
CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_ANYBODY | CTLFLAG_MPSAFE
| CTLFLAG_CAPRW, 0, 0, sysctl_sysctl_name2oid, "I", "");
static int
sysctl_sysctl_oidfmt(SYSCTL_HANDLER_ARGS)
{
struct sysctl_oid *oid;
int error;
SYSCTL_XLOCK();
error = sysctl_find_oid(arg1, arg2, &oid, NULL, req);
if (error)
goto out;
if (oid->oid_fmt == NULL) {
error = ENOENT;
goto out;
}
error = SYSCTL_OUT(req, &oid->oid_kind, sizeof(oid->oid_kind));
if (error)
goto out;
error = SYSCTL_OUT(req, oid->oid_fmt, strlen(oid->oid_fmt) + 1);
out:
SYSCTL_XUNLOCK();
return (error);
}
static SYSCTL_NODE(_sysctl, 4, oidfmt, CTLFLAG_RD|CTLFLAG_MPSAFE|CTLFLAG_CAPRD,
sysctl_sysctl_oidfmt, "");
static int
sysctl_sysctl_oiddescr(SYSCTL_HANDLER_ARGS)
{
struct sysctl_oid *oid;
int error;
SYSCTL_XLOCK();
error = sysctl_find_oid(arg1, arg2, &oid, NULL, req);
if (error)
goto out;
if (oid->oid_descr == NULL) {
error = ENOENT;
goto out;
}
error = SYSCTL_OUT(req, oid->oid_descr, strlen(oid->oid_descr) + 1);
out:
SYSCTL_XUNLOCK();
return (error);
}
static SYSCTL_NODE(_sysctl, 5, oiddescr, CTLFLAG_RD|CTLFLAG_CAPRD,
sysctl_sysctl_oiddescr, "");
/*
* Default "handler" functions.
*/
/*
* Handle an int, signed or unsigned.
* Two cases:
* a variable: point arg1 at it.
* a constant: pass it in arg2.
*/
int
sysctl_handle_int(SYSCTL_HANDLER_ARGS)
{
int tmpout, error = 0;
/*
* Attempt to get a coherent snapshot by making a copy of the data.
*/
if (arg1)
tmpout = *(int *)arg1;
else
tmpout = arg2;
error = SYSCTL_OUT(req, &tmpout, sizeof(int));
if (error || !req->newptr)
return (error);
if (!arg1)
error = EPERM;
else
error = SYSCTL_IN(req, arg1, sizeof(int));
return (error);
}
/*
* Based on on sysctl_handle_int() convert milliseconds into ticks.
* Note: this is used by TCP.
*/
int
sysctl_msec_to_ticks(SYSCTL_HANDLER_ARGS)
{
int error, s, tt;
tt = *(int *)arg1;
s = (int)((int64_t)tt * 1000 / hz);
error = sysctl_handle_int(oidp, &s, 0, req);
if (error || !req->newptr)
return (error);
tt = (int)((int64_t)s * hz / 1000);
if (tt < 1)
return (EINVAL);
*(int *)arg1 = tt;
return (0);
}
/*
* Handle a long, signed or unsigned.
* Two cases:
* a variable: point arg1 at it.
* a constant: pass it in arg2.
*/
int
sysctl_handle_long(SYSCTL_HANDLER_ARGS)
{
int error = 0;
long tmplong;
#ifdef SCTL_MASK32
int tmpint;
#endif
/*
* Attempt to get a coherent snapshot by making a copy of the data.
*/
if (arg1)
tmplong = *(long *)arg1;
else
tmplong = arg2;
#ifdef SCTL_MASK32
if (req->flags & SCTL_MASK32) {
tmpint = tmplong;
error = SYSCTL_OUT(req, &tmpint, sizeof(int));
} else
#endif
error = SYSCTL_OUT(req, &tmplong, sizeof(long));
if (error || !req->newptr)
return (error);
if (!arg1)
error = EPERM;
#ifdef SCTL_MASK32
else if (req->flags & SCTL_MASK32) {
error = SYSCTL_IN(req, &tmpint, sizeof(int));
*(long *)arg1 = (long)tmpint;
}
#endif
else
error = SYSCTL_IN(req, arg1, sizeof(long));
return (error);
}
/*
* Handle a 64 bit int, signed or unsigned.
* Two cases:
* a variable: point arg1 at it.
* a constant: pass it in arg2.
*/
int
sysctl_handle_64(SYSCTL_HANDLER_ARGS)
{
int error = 0;
uint64_t tmpout;
/*
* Attempt to get a coherent snapshot by making a copy of the data.
*/
if (arg1)
tmpout = *(uint64_t *)arg1;
else
tmpout = arg2;
error = SYSCTL_OUT(req, &tmpout, sizeof(uint64_t));
if (error || !req->newptr)
return (error);
if (!arg1)
error = EPERM;
else
error = SYSCTL_IN(req, arg1, sizeof(uint64_t));
return (error);
}
/*
* Handle our generic '\0' terminated 'C' string.
* Two cases:
* a variable string: point arg1 at it, arg2 is max length.
* a constant string: point arg1 at it, arg2 is zero.
*/
int
sysctl_handle_string(SYSCTL_HANDLER_ARGS)
{
size_t outlen;
int error = 0, ro_string = 0;
/*
* A zero-length buffer indicates a fixed size read-only
* string:
*/
if (arg2 == 0) {
arg2 = strlen((char *)arg1) + 1;
ro_string = 1;
}
if (req->oldptr != NULL) {
char *tmparg;
if (ro_string) {
tmparg = arg1;
} else {
/* try to make a coherent snapshot of the string */
tmparg = malloc(arg2, M_SYSCTLTMP, M_WAITOK);
memcpy(tmparg, arg1, arg2);
}
outlen = strnlen(tmparg, arg2 - 1) + 1;
error = SYSCTL_OUT(req, tmparg, outlen);
if (!ro_string)
free(tmparg, M_SYSCTLTMP);
} else {
outlen = strnlen((char *)arg1, arg2 - 1) + 1;
error = SYSCTL_OUT(req, NULL, outlen);
}
if (error || !req->newptr)
return (error);
if ((req->newlen - req->newidx) >= arg2) {
error = EINVAL;
} else {
arg2 = (req->newlen - req->newidx);
error = SYSCTL_IN(req, arg1, arg2);
((char *)arg1)[arg2] = '\0';
}
return (error);
}
/*
* Handle any kind of opaque data.
* arg1 points to it, arg2 is the size.
*/
int
sysctl_handle_opaque(SYSCTL_HANDLER_ARGS)
{
int error, tries;
u_int generation;
struct sysctl_req req2;
/*
* Attempt to get a coherent snapshot, by using the thread
* pre-emption counter updated from within mi_switch() to
* determine if we were pre-empted during a bcopy() or
* copyout(). Make 3 attempts at doing this before giving up.
* If we encounter an error, stop immediately.
*/
tries = 0;
req2 = *req;
retry:
generation = curthread->td_generation;
error = SYSCTL_OUT(req, arg1, arg2);
if (error)
return (error);
tries++;
if (generation != curthread->td_generation && tries < 3) {
*req = req2;
goto retry;
}
error = SYSCTL_IN(req, arg1, arg2);
return (error);
}
/*
* Transfer functions to/from kernel space.
* XXX: rather untested at this point
*/
static int
sysctl_old_kernel(struct sysctl_req *req, const void *p, size_t l)
{
size_t i = 0;
if (req->oldptr) {
i = l;
if (req->oldlen <= req->oldidx)
i = 0;
else
if (i > req->oldlen - req->oldidx)
i = req->oldlen - req->oldidx;
if (i > 0)
bcopy(p, (char *)req->oldptr + req->oldidx, i);
}
req->oldidx += l;
if (req->oldptr && i != l)
return (ENOMEM);
return (0);
}
static int
sysctl_new_kernel(struct sysctl_req *req, void *p, size_t l)
{
if (!req->newptr)
return (0);
if (req->newlen - req->newidx < l)
return (EINVAL);
bcopy((char *)req->newptr + req->newidx, p, l);
req->newidx += l;
return (0);
}
int
kernel_sysctl(struct thread *td, int *name, u_int namelen, void *old,
size_t *oldlenp, void *new, size_t newlen, size_t *retval, int flags)
{
int error = 0;
struct sysctl_req req;
bzero(&req, sizeof req);
req.td = td;
req.flags = flags;
if (oldlenp) {
req.oldlen = *oldlenp;
}
req.validlen = req.oldlen;
if (old) {
req.oldptr= old;
}
if (new != NULL) {
req.newlen = newlen;
req.newptr = new;
}
req.oldfunc = sysctl_old_kernel;
req.newfunc = sysctl_new_kernel;
req.lock = REQ_UNWIRED;
SYSCTL_XLOCK();
error = sysctl_root(0, name, namelen, &req);
SYSCTL_XUNLOCK();
if (req.lock == REQ_WIRED && req.validlen > 0)
vsunlock(req.oldptr, req.validlen);
if (error && error != ENOMEM)
return (error);
if (retval) {
if (req.oldptr && req.oldidx > req.validlen)
*retval = req.validlen;
else
*retval = req.oldidx;
}
return (error);
}
int
kernel_sysctlbyname(struct thread *td, char *name, void *old, size_t *oldlenp,
void *new, size_t newlen, size_t *retval, int flags)
{
int oid[CTL_MAXNAME];
size_t oidlen, plen;
int error;
oid[0] = 0; /* sysctl internal magic */
oid[1] = 3; /* name2oid */
oidlen = sizeof(oid);
error = kernel_sysctl(td, oid, 2, oid, &oidlen,
(void *)name, strlen(name), &plen, flags);
if (error)
return (error);
error = kernel_sysctl(td, oid, plen / sizeof(int), old, oldlenp,
new, newlen, retval, flags);
return (error);
}
/*
* Transfer function to/from user space.
*/
static int
sysctl_old_user(struct sysctl_req *req, const void *p, size_t l)
{
size_t i, len, origidx;
int error;
origidx = req->oldidx;
req->oldidx += l;
if (req->oldptr == NULL)
return (0);
/*
* If we have not wired the user supplied buffer and we are currently
* holding locks, drop a witness warning, as it's possible that
* write operations to the user page can sleep.
*/
if (req->lock != REQ_WIRED)
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
"sysctl_old_user()");
i = l;
len = req->validlen;
if (len <= origidx)
i = 0;
else {
if (i > len - origidx)
i = len - origidx;
if (req->lock == REQ_WIRED) {
error = copyout_nofault(p, (char *)req->oldptr +
origidx, i);
} else
error = copyout(p, (char *)req->oldptr + origidx, i);
if (error != 0)
return (error);
}
if (i < l)
return (ENOMEM);
return (0);
}
static int
sysctl_new_user(struct sysctl_req *req, void *p, size_t l)
{
int error;
if (!req->newptr)
return (0);
if (req->newlen - req->newidx < l)
return (EINVAL);
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
"sysctl_new_user()");
error = copyin((char *)req->newptr + req->newidx, p, l);
req->newidx += l;
return (error);
}
/*
* Wire the user space destination buffer. If set to a value greater than
* zero, the len parameter limits the maximum amount of wired memory.
*/
int
sysctl_wire_old_buffer(struct sysctl_req *req, size_t len)
{
int ret;
size_t wiredlen;
wiredlen = (len > 0 && len < req->oldlen) ? len : req->oldlen;
ret = 0;
if (req->lock != REQ_WIRED && req->oldptr &&
req->oldfunc == sysctl_old_user) {
if (wiredlen != 0) {
ret = vslock(req->oldptr, wiredlen);
if (ret != 0) {
if (ret != ENOMEM)
return (ret);
wiredlen = 0;
}
}
req->lock = REQ_WIRED;
req->validlen = wiredlen;
}
return (0);
}
int
sysctl_find_oid(int *name, u_int namelen, struct sysctl_oid **noid,
int *nindx, struct sysctl_req *req)
{
struct sysctl_oid_list *lsp;
struct sysctl_oid *oid;
int indx;
SYSCTL_ASSERT_XLOCKED();
lsp = &sysctl__children;
indx = 0;
while (indx < CTL_MAXNAME) {
SLIST_FOREACH(oid, lsp, oid_link) {
if (oid->oid_number == name[indx])
break;
}
if (oid == NULL)
return (ENOENT);
indx++;
if ((oid->oid_kind & CTLTYPE) == CTLTYPE_NODE) {
if (oid->oid_handler != NULL || indx == namelen) {
*noid = oid;
if (nindx != NULL)
*nindx = indx;
KASSERT((oid->oid_kind & CTLFLAG_DYING) == 0,
("%s found DYING node %p", __func__, oid));
return (0);
}
lsp = SYSCTL_CHILDREN(oid);
} else if (indx == namelen) {
*noid = oid;
if (nindx != NULL)
*nindx = indx;
KASSERT((oid->oid_kind & CTLFLAG_DYING) == 0,
("%s found DYING node %p", __func__, oid));
return (0);
} else {
return (ENOTDIR);
}
}
return (ENOENT);
}
/*
* Traverse our tree, and find the right node, execute whatever it points
* to, and return the resulting error code.
*/
static int
sysctl_root(SYSCTL_HANDLER_ARGS)
{
struct sysctl_oid *oid;
int error, indx, lvl;
SYSCTL_ASSERT_XLOCKED();
error = sysctl_find_oid(arg1, arg2, &oid, &indx, req);
if (error)
return (error);
if ((oid->oid_kind & CTLTYPE) == CTLTYPE_NODE) {
/*
* You can't call a sysctl when it's a node, but has
* no handler. Inform the user that it's a node.
* The indx may or may not be the same as namelen.
*/
if (oid->oid_handler == NULL)
return (EISDIR);
}
/* Is this sysctl writable? */
if (req->newptr && !(oid->oid_kind & CTLFLAG_WR))
return (EPERM);
KASSERT(req->td != NULL, ("sysctl_root(): req->td == NULL"));
#ifdef CAPABILITY_MODE
/*
* If the process is in capability mode, then don't permit reading or
* writing unless specifically granted for the node.
*/
if (IN_CAPABILITY_MODE(req->td)) {
if (req->oldptr && !(oid->oid_kind & CTLFLAG_CAPRD))
return (EPERM);
if (req->newptr && !(oid->oid_kind & CTLFLAG_CAPWR))
return (EPERM);
}
#endif
/* Is this sysctl sensitive to securelevels? */
if (req->newptr && (oid->oid_kind & CTLFLAG_SECURE)) {
lvl = (oid->oid_kind & CTLMASK_SECURE) >> CTLSHIFT_SECURE;
error = securelevel_gt(req->td->td_ucred, lvl);
if (error)
return (error);
}
/* Is this sysctl writable by only privileged users? */
if (req->newptr && !(oid->oid_kind & CTLFLAG_ANYBODY)) {
int priv;
if (oid->oid_kind & CTLFLAG_PRISON)
priv = PRIV_SYSCTL_WRITEJAIL;
#ifdef VIMAGE
else if ((oid->oid_kind & CTLFLAG_VNET) &&
prison_owns_vnet(req->td->td_ucred))
priv = PRIV_SYSCTL_WRITEJAIL;
#endif
else
priv = PRIV_SYSCTL_WRITE;
error = priv_check(req->td, priv);
if (error)
return (error);
}
if (!oid->oid_handler)
return (EINVAL);
if ((oid->oid_kind & CTLTYPE) == CTLTYPE_NODE) {
arg1 = (int *)arg1 + indx;
arg2 -= indx;
} else {
arg1 = oid->oid_arg1;
arg2 = oid->oid_arg2;
}
#ifdef MAC
error = mac_system_check_sysctl(req->td->td_ucred, oid, arg1, arg2,
req);
if (error != 0)
return (error);
#endif
#ifdef VIMAGE
if ((oid->oid_kind & CTLFLAG_VNET) && arg1 != NULL)
arg1 = (void *)(curvnet->vnet_data_base + (uintptr_t)arg1);
#endif
error = sysctl_root_handler_locked(oid, arg1, arg2, req);
KFAIL_POINT_ERROR(_debug_fail_point, sysctl_running, error);
return (error);
}
#ifndef _SYS_SYSPROTO_H_
struct sysctl_args {
int *name;
u_int namelen;
void *old;
size_t *oldlenp;
void *new;
size_t newlen;
};
#endif
int
sys___sysctl(struct thread *td, struct sysctl_args *uap)
{
int error, i, name[CTL_MAXNAME];
size_t j;
if (uap->namelen > CTL_MAXNAME || uap->namelen < 2)
return (EINVAL);
error = copyin(uap->name, &name, uap->namelen * sizeof(int));
if (error)
return (error);
error = userland_sysctl(td, name, uap->namelen,
uap->old, uap->oldlenp, 0,
uap->new, uap->newlen, &j, 0);
if (error && error != ENOMEM)
return (error);
if (uap->oldlenp) {
i = copyout(&j, uap->oldlenp, sizeof(j));
if (i)
return (i);
}
return (error);
}
/*
* This is used from various compatibility syscalls too. That's why name
* must be in kernel space.
*/
int
userland_sysctl(struct thread *td, int *name, u_int namelen, void *old,
size_t *oldlenp, int inkernel, void *new, size_t newlen, size_t *retval,
int flags)
{
int error = 0, memlocked;
struct sysctl_req req;
bzero(&req, sizeof req);
req.td = td;
req.flags = flags;
if (oldlenp) {
if (inkernel) {
req.oldlen = *oldlenp;
} else {
error = copyin(oldlenp, &req.oldlen, sizeof(*oldlenp));
if (error)
return (error);
}
}
req.validlen = req.oldlen;
if (old) {
if (!useracc(old, req.oldlen, VM_PROT_WRITE))
return (EFAULT);
req.oldptr= old;
}
if (new != NULL) {
if (!useracc(new, newlen, VM_PROT_READ))
return (EFAULT);
req.newlen = newlen;
req.newptr = new;
}
req.oldfunc = sysctl_old_user;
req.newfunc = sysctl_new_user;
req.lock = REQ_UNWIRED;
#ifdef KTRACE
if (KTRPOINT(curthread, KTR_SYSCTL))
ktrsysctl(name, namelen);
#endif
if (req.oldlen > PAGE_SIZE) {
memlocked = 1;
sx_xlock(&sysctlmemlock);
} else
memlocked = 0;
CURVNET_SET(TD_TO_VNET(td));
for (;;) {
req.oldidx = 0;
req.newidx = 0;
SYSCTL_XLOCK();
error = sysctl_root(0, name, namelen, &req);
SYSCTL_XUNLOCK();
if (error != EAGAIN)
break;
kern_yield(PRI_USER);
}
CURVNET_RESTORE();
if (req.lock == REQ_WIRED && req.validlen > 0)
vsunlock(req.oldptr, req.validlen);
if (memlocked)
sx_xunlock(&sysctlmemlock);
if (error && error != ENOMEM)
return (error);
if (retval) {
if (req.oldptr && req.oldidx > req.validlen)
*retval = req.validlen;
else
*retval = req.oldidx;
}
return (error);
}
/*
* Drain into a sysctl struct. The user buffer should be wired if a page
* fault would cause issue.
*/
static int
sbuf_sysctl_drain(void *arg, const char *data, int len)
{
struct sysctl_req *req = arg;
int error;
error = SYSCTL_OUT(req, data, len);
KASSERT(error >= 0, ("Got unexpected negative value %d", error));
return (error == 0 ? len : -error);
}
struct sbuf *
sbuf_new_for_sysctl(struct sbuf *s, char *buf, int length,
struct sysctl_req *req)
{
s = sbuf_new(s, buf, length, SBUF_FIXEDLEN);
sbuf_set_drain(s, sbuf_sysctl_drain, req);
return (s);
}
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