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freebsd-skq/sys/kern/kern_sysctl.c
mjg 2b6199af16 sysctl: only take mem lock if oldlen is > 4 * PAGE_SIZE 
The previous limit of just one page is hit by ps.

The entire mechanism should be reworked, if not whacked. It seems the intent
is to reduce kernel dos-ability - some handlers wire the amount of memory
passed here. Handlers should probably stop wiring in the first place or in
the worst case indicate they are doing so so that the check is done only if
necessary. It should also probably be a counter, not a lock.

MFC after:	1 week
2017-10-19 01:38:31 +00:00

2174 lines
49 KiB
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.
* 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_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/rmlock.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_wlock() and sysctl_wunlock() 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 rmlock sysctllock;
static struct sx __exclusive_cache_line sysctlmemlock;
#define SYSCTL_WLOCK() rm_wlock(&sysctllock)
#define SYSCTL_WUNLOCK() rm_wunlock(&sysctllock)
#define SYSCTL_RLOCK(tracker) rm_rlock(&sysctllock, (tracker))
#define SYSCTL_RUNLOCK(tracker) rm_runlock(&sysctllock, (tracker))
#define SYSCTL_WLOCKED() rm_wowned(&sysctllock)
#define SYSCTL_ASSERT_LOCKED() rm_assert(&sysctllock, RA_LOCKED)
#define SYSCTL_ASSERT_WLOCKED() rm_assert(&sysctllock, RA_WLOCKED)
#define SYSCTL_ASSERT_RLOCKED() rm_assert(&sysctllock, RA_RLOCKED)
#define SYSCTL_INIT() rm_init_flags(&sysctllock, "sysctl lock", \
RM_SLEEPABLE)
#define SYSCTL_SLEEP(ch, wmesg, timo) \
rm_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_LOCKED();
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_wlock(void)
{
SYSCTL_WLOCK();
}
void
sysctl_wunlock(void)
{
SYSCTL_WUNLOCK();
}
static int
sysctl_root_handler_locked(struct sysctl_oid *oid, void *arg1, intmax_t arg2,
struct sysctl_req *req, struct rm_priotracker *tracker)
{
int error;
if (oid->oid_kind & CTLFLAG_DYN)
atomic_add_int(&oid->oid_running, 1);
if (tracker != NULL)
SYSCTL_RUNLOCK(tracker);
else
SYSCTL_WUNLOCK();
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);
KFAIL_POINT_ERROR(_debug_fail_point, sysctl_running, error);
if (tracker != NULL)
SYSCTL_RLOCK(tracker);
else
SYSCTL_WLOCK();
if (oid->oid_kind & CTLFLAG_DYN) {
if (atomic_fetchadd_int(&oid->oid_running, -1) == 1 &&
(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;
uint8_t val_8;
uint16_t val_16;
uint32_t val_32;
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_S8:
if (getenv_int(path + rem, &val_int) == 0)
return;
val_8 = val_int;
req.newlen = sizeof(val_8);
req.newptr = &val_8;
break;
case CTLTYPE_S16:
if (getenv_int(path + rem, &val_int) == 0)
return;
val_16 = val_int;
req.newlen = sizeof(val_16);
req.newptr = &val_16;
break;
case CTLTYPE_S32:
if (getenv_long(path + rem, &val_long) == 0)
return;
val_32 = val_long;
req.newlen = sizeof(val_32);
req.newptr = &val_32;
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_U8:
if (getenv_uint(path + rem, (unsigned int *)&val_int) == 0)
return;
val_8 = val_int;
req.newlen = sizeof(val_8);
req.newptr = &val_8;
break;
case CTLTYPE_U16:
if (getenv_uint(path + rem, (unsigned int *)&val_int) == 0)
return;
val_16 = val_int;
req.newlen = sizeof(val_16);
req.newptr = &val_16;
break;
case CTLTYPE_U32:
if (getenv_ulong(path + rem, (unsigned long *)&val_long) == 0)
return;
val_32 = val_long;
req.newlen = sizeof(val_32);
req.newptr = &val_32;
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 = kern_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, NULL);
if (error != 0)
printf("Setting sysctl %s failed: %d\n", path + rem, error);
if (penv != NULL)
freeenv(penv);
}
static int
sbuf_printf_drain(void *arg __unused, const char *data, int len)
{
return (printf("%.*s", len, data));
}
/*
* Locate the path to a given oid. Returns the length of the resulting path,
* or -1 if the oid was not found. nodes must have room for CTL_MAXNAME
* elements and be NULL initialized.
*/
static int
sysctl_search_oid(struct sysctl_oid **nodes, struct sysctl_oid *needle)
{
int indx;
SYSCTL_ASSERT_LOCKED();
indx = 0;
while (indx < CTL_MAXNAME && indx >= 0) {
if (nodes[indx] == NULL && indx == 0)
nodes[indx] = SLIST_FIRST(&sysctl__children);
else if (nodes[indx] == NULL)
nodes[indx] = SLIST_FIRST(&nodes[indx - 1]->oid_children);
else
nodes[indx] = SLIST_NEXT(nodes[indx], oid_link);
if (nodes[indx] == needle)
return (indx + 1);
if (nodes[indx] == NULL) {
indx--;
continue;
}
if ((nodes[indx]->oid_kind & CTLTYPE) == CTLTYPE_NODE) {
indx++;
continue;
}
}
return (-1);
}
static void
sysctl_warn_reuse(const char *func, struct sysctl_oid *leaf)
{
struct sysctl_oid *nodes[CTL_MAXNAME];
char buf[128];
struct sbuf sb;
int rc, i;
(void)sbuf_new(&sb, buf, sizeof(buf), SBUF_FIXEDLEN | SBUF_INCLUDENUL);
sbuf_set_drain(&sb, sbuf_printf_drain, NULL);
sbuf_printf(&sb, "%s: can't re-use a leaf (", __func__);
memset(nodes, 0, sizeof(nodes));
rc = sysctl_search_oid(nodes, leaf);
if (rc > 0) {
for (i = 0; i < rc; i++)
sbuf_printf(&sb, "%s%.*s", nodes[i]->oid_name,
i != (rc - 1), ".");
} else {
sbuf_printf(&sb, "%s", leaf->oid_name);
}
sbuf_printf(&sb, ")!\n");
(void)sbuf_finish(&sb);
}
#ifdef SYSCTL_DEBUG
static int
sysctl_reuse_test(SYSCTL_HANDLER_ARGS)
{
struct rm_priotracker tracker;
SYSCTL_RLOCK(&tracker);
sysctl_warn_reuse(__func__, oidp);
SYSCTL_RUNLOCK(&tracker);
return (0);
}
SYSCTL_PROC(_sysctl, 0, reuse_test, CTLTYPE_STRING|CTLFLAG_RD|CTLFLAG_MPSAFE,
0, 0, sysctl_reuse_test, "-", "");
#endif
void
sysctl_register_oid(struct sysctl_oid *oidp)
{
struct sysctl_oid_list *parent = oidp->oid_parent;
struct sysctl_oid *p;
struct sysctl_oid *q;
int oid_number;
int timeout = 2;
/*
* First check if another oid with the same name already
* exists in the parent's list.
*/
SYSCTL_ASSERT_WLOCKED();
p = sysctl_find_oidname(oidp->oid_name, parent);
if (p != NULL) {
if ((p->oid_kind & CTLTYPE) == CTLTYPE_NODE) {
p->oid_refcnt++;
return;
} else {
sysctl_warn_reuse(__func__, p);
return;
}
}
/* get current OID number */
oid_number = oidp->oid_number;
#if (OID_AUTO >= 0)
#error "OID_AUTO is expected to be a negative value"
#endif
/*
* Any negative OID number qualifies as OID_AUTO. Valid OID
* numbers should always be positive.
*
* NOTE: DO NOT change the starting value here, change it in
* <sys/sysctl.h>, and make sure it is at least 256 to
* accommodate e.g. net.inet.raw as a static sysctl node.
*/
if (oid_number < 0) {
static int newoid;
/*
* By decrementing the next OID number we spend less
* time inserting the OIDs into a sorted list.
*/
if (--newoid < CTL_AUTO_START)
newoid = 0x7fffffff;
oid_number = newoid;
}
/*
* Insert the OID into the parent's list sorted by OID number.
*/
retry:
q = NULL;
SLIST_FOREACH(p, parent, oid_link) {
/* check if the current OID number is in use */
if (oid_number == p->oid_number) {
/* get the next valid OID number */
if (oid_number < CTL_AUTO_START ||
oid_number == 0x7fffffff) {
/* wraparound - restart */
oid_number = CTL_AUTO_START;
/* don't loop forever */
if (!timeout--)
panic("sysctl: Out of OID numbers\n");
goto retry;
} else {
oid_number++;
}
} else if (oid_number < p->oid_number)
break;
q = p;
}
/* check for non-auto OID number collision */
if (oidp->oid_number >= 0 && oidp->oid_number < CTL_AUTO_START &&
oid_number >= CTL_AUTO_START) {
printf("sysctl: OID number(%d) is already in use for '%s'\n",
oidp->oid_number, oidp->oid_name);
}
/* update the OID number, if any */
oidp->oid_number = oid_number;
if (q != NULL)
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) {
/* only fetch value once */
oidp->oid_kind |= CTLFLAG_NOFETCH;
/* try to fetch value from kernel environment */
sysctl_load_tunable_by_oid_locked(oidp);
}
}
void
sysctl_register_disabled_oid(struct sysctl_oid *oidp)
{
/*
* Mark the leaf as dormant if it's not to be immediately enabled.
* We do not disable nodes as they can be shared between modules
* and it is always safe to access a node.
*/
KASSERT((oidp->oid_kind & CTLFLAG_DORMANT) == 0,
("internal flag is set in oid_kind"));
if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE)
oidp->oid_kind |= CTLFLAG_DORMANT;
sysctl_register_oid(oidp);
}
void
sysctl_enable_oid(struct sysctl_oid *oidp)
{
SYSCTL_ASSERT_WLOCKED();
if ((oidp->oid_kind & CTLTYPE) == CTLTYPE_NODE) {
KASSERT((oidp->oid_kind & CTLFLAG_DORMANT) == 0,
("sysctl node is marked as dormant"));
return;
}
KASSERT((oidp->oid_kind & CTLFLAG_DORMANT) != 0,
("enabling already enabled sysctl oid"));
oidp->oid_kind &= ~CTLFLAG_DORMANT;
}
void
sysctl_unregister_oid(struct sysctl_oid *oidp)
{
struct sysctl_oid *p;
int error;
SYSCTL_ASSERT_WLOCKED();
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_WLOCK();
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 occurred.
* 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_WUNLOCK();
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_WUNLOCK();
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_WLOCKED();
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_WLOCKED();
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_WLOCK();
e = sysctl_ctx_entry_find(clist, oidp);
if (e != NULL) {
TAILQ_REMOVE(clist, e, link);
SYSCTL_WUNLOCK();
free(e, M_SYSCTLOID);
return (0);
} else {
SYSCTL_WUNLOCK();
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_WLOCK();
error = sysctl_remove_oid_locked(oidp, del, recurse);
SYSCTL_WUNLOCK();
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_WLOCK();
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_WUNLOCK();
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_WLOCKED();
if (oidp == NULL)
return(EINVAL);
if ((oidp->oid_kind & CTLFLAG_DYN) == 0) {
printf("Warning: can't remove non-dynamic nodes (%s)!\n",
oidp->oid_name);
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);
if (oidp->oid_label)
free(__DECONST(char *, oidp->oid_label),
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, intmax_t arg2,
int (*handler)(SYSCTL_HANDLER_ARGS), const char *fmt, const char *descr,
const char *label)
{
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_WLOCK();
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_WUNLOCK();
return (oidp);
} else {
sysctl_warn_reuse(__func__, oidp);
SYSCTL_WUNLOCK();
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);
if (label != NULL)
oidp->oid_label = strdup(label, M_SYSCTLOID);
/* Update the context, if used */
if (clist != NULL)
sysctl_ctx_entry_add(clist, oidp);
/* Register this oid */
sysctl_register_oid(oidp);
SYSCTL_WUNLOCK();
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_WLOCK();
oldname = __DECONST(char *, oidp->oid_name);
oidp->oid_name = newname;
SYSCTL_WUNLOCK();
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_WLOCK();
if (oid->oid_parent == parent) {
SYSCTL_WUNLOCK();
return (0);
}
oidp = sysctl_find_oidname(oid->oid_name, parent);
if (oidp != NULL) {
SYSCTL_WUNLOCK();
return (EEXIST);
}
sysctl_unregister_oid(oid);
oid->oid_parent = parent;
oid->oid_number = OID_AUTO;
sysctl_register_oid(oid);
SYSCTL_WUNLOCK();
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_WLOCK();
SET_FOREACH(oidp, sysctl_set)
sysctl_register_oid(*oidp);
SYSCTL_WUNLOCK();
}
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 of the "..." OID.
* {0,6,...} return the aggregation label of 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_LOCKED();
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_S8: printf(" int8_t\n"); break;
case CTLTYPE_S16: printf(" int16_t\n"); break;
case CTLTYPE_S32: printf(" int32_t\n"); break;
case CTLTYPE_S64: printf(" int64_t\n"); break;
case CTLTYPE_U8: printf(" uint8_t\n"); break;
case CTLTYPE_U16: printf(" uint16_t\n"); break;
case CTLTYPE_U32: printf(" uint32_t\n"); break;
case CTLTYPE_U64: printf(" uint64_t\n"); break;
case CTLTYPE_OPAQUE: printf(" Opaque/struct\n"); break;
default: printf("\n");
}
}
}
static int
sysctl_sysctl_debug(SYSCTL_HANDLER_ARGS)
{
struct rm_priotracker tracker;
int error;
error = priv_check(req->td, PRIV_SYSCTL_DEBUG);
if (error)
return (error);
SYSCTL_RLOCK(&tracker);
sysctl_sysctl_debug_dump_node(&sysctl__children, 0);
SYSCTL_RUNLOCK(&tracker);
return (ENOENT);
}
SYSCTL_PROC(_sysctl, 0, debug, CTLTYPE_STRING|CTLFLAG_RD|CTLFLAG_MPSAFE,
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;
struct rm_priotracker tracker;
char buf[10];
SYSCTL_RLOCK(&tracker);
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 = NULL;
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_RUNLOCK(&tracker);
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_MPSAFE | 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_LOCKED();
*len = level;
SLIST_FOREACH(oidp, lsp, oid_link) {
*next = oidp->oid_number;
*oidpp = oidp;
if ((oidp->oid_kind & (CTLFLAG_SKIP | CTLFLAG_DORMANT)) != 0)
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;
struct rm_priotracker tracker;
int newoid[CTL_MAXNAME];
SYSCTL_RLOCK(&tracker);
i = sysctl_sysctl_next_ls(lsp, name, namelen, newoid, &j, 1, &oid);
SYSCTL_RUNLOCK(&tracker);
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_MPSAFE | 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_LOCKED();
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 = NULL;
struct rm_priotracker tracker;
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_RLOCK(&tracker);
error = name2oid(p, oid, &len, &op);
SYSCTL_RUNLOCK(&tracker);
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;
struct rm_priotracker tracker;
int error;
SYSCTL_RLOCK(&tracker);
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_RUNLOCK(&tracker);
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;
struct rm_priotracker tracker;
int error;
SYSCTL_RLOCK(&tracker);
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_RUNLOCK(&tracker);
return (error);
}
static SYSCTL_NODE(_sysctl, 5, oiddescr, CTLFLAG_RD|CTLFLAG_MPSAFE|CTLFLAG_CAPRD,
sysctl_sysctl_oiddescr, "");
static int
sysctl_sysctl_oidlabel(SYSCTL_HANDLER_ARGS)
{
struct sysctl_oid *oid;
struct rm_priotracker tracker;
int error;
SYSCTL_RLOCK(&tracker);
error = sysctl_find_oid(arg1, arg2, &oid, NULL, req);
if (error)
goto out;
if (oid->oid_label == NULL) {
error = ENOENT;
goto out;
}
error = SYSCTL_OUT(req, oid->oid_label, strlen(oid->oid_label) + 1);
out:
SYSCTL_RUNLOCK(&tracker);
return (error);
}
static SYSCTL_NODE(_sysctl, 6, oidlabel,
CTLFLAG_RD | CTLFLAG_MPSAFE | CTLFLAG_CAPRD, sysctl_sysctl_oidlabel, "");
/*
* Default "handler" functions.
*/
/*
* Handle a bool.
* Two cases:
* a variable: point arg1 at it.
* a constant: pass it in arg2.
*/
int
sysctl_handle_bool(SYSCTL_HANDLER_ARGS)
{
uint8_t temp;
int error;
/*
* Attempt to get a coherent snapshot by making a copy of the data.
*/
if (arg1)
temp = *(bool *)arg1 ? 1 : 0;
else
temp = arg2 ? 1 : 0;
error = SYSCTL_OUT(req, &temp, sizeof(temp));
if (error || !req->newptr)
return (error);
if (!arg1)
error = EPERM;
else {
error = SYSCTL_IN(req, &temp, sizeof(temp));
if (!error)
*(bool *)arg1 = temp ? 1 : 0;
}
return (error);
}
/*
* Handle an int8_t, signed or unsigned.
* Two cases:
* a variable: point arg1 at it.
* a constant: pass it in arg2.
*/
int
sysctl_handle_8(SYSCTL_HANDLER_ARGS)
{
int8_t tmpout;
int error = 0;
/*
* Attempt to get a coherent snapshot by making a copy of the data.
*/
if (arg1)
tmpout = *(int8_t *)arg1;
else
tmpout = arg2;
error = SYSCTL_OUT(req, &tmpout, sizeof(tmpout));
if (error || !req->newptr)
return (error);
if (!arg1)
error = EPERM;
else
error = SYSCTL_IN(req, arg1, sizeof(tmpout));
return (error);
}
/*
* Handle an int16_t, signed or unsigned.
* Two cases:
* a variable: point arg1 at it.
* a constant: pass it in arg2.
*/
int
sysctl_handle_16(SYSCTL_HANDLER_ARGS)
{
int16_t tmpout;
int error = 0;
/*
* Attempt to get a coherent snapshot by making a copy of the data.
*/
if (arg1)
tmpout = *(int16_t *)arg1;
else
tmpout = arg2;
error = SYSCTL_OUT(req, &tmpout, sizeof(tmpout));
if (error || !req->newptr)
return (error);
if (!arg1)
error = EPERM;
else
error = SYSCTL_IN(req, arg1, sizeof(tmpout));
return (error);
}
/*
* Handle an int32_t, signed or unsigned.
* Two cases:
* a variable: point arg1 at it.
* a constant: pass it in arg2.
*/
int
sysctl_handle_32(SYSCTL_HANDLER_ARGS)
{
int32_t tmpout;
int error = 0;
/*
* Attempt to get a coherent snapshot by making a copy of the data.
*/
if (arg1)
tmpout = *(int32_t *)arg1;
else
tmpout = arg2;
error = SYSCTL_OUT(req, &tmpout, sizeof(tmpout));
if (error || !req->newptr)
return (error);
if (!arg1)
error = EPERM;
else
error = SYSCTL_IN(req, arg1, sizeof(tmpout));
return (error);
}
/*
* 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;
error = sysctl_root(0, name, namelen, &req);
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_LOCKED();
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) {
if ((oid->oid_kind & CTLFLAG_DORMANT) != 0)
return (ENOENT);
*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;
struct rm_priotracker tracker;
int error, indx, lvl;
SYSCTL_RLOCK(&tracker);
error = sysctl_find_oid(arg1, arg2, &oid, &indx, req);
if (error)
goto out;
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) {
error = EISDIR;
goto out;
}
}
/* Is this sysctl writable? */
if (req->newptr && !(oid->oid_kind & CTLFLAG_WR)) {
error = EPERM;
goto out;
}
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)) ||
(req->newptr && !(oid->oid_kind & CTLFLAG_CAPWR))) {
error = EPERM;
goto out;
}
}
#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)
goto out;
}
/* 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)
goto out;
}
if (!oid->oid_handler) {
error = EINVAL;
goto out;
}
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)
goto out;
#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, &tracker);
out:
SYSCTL_RUNLOCK(&tracker);
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;
req.oldptr = old;
if (new != NULL) {
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
memlocked = 0;
if (req.oldptr && req.oldlen > 4 * PAGE_SIZE) {
memlocked = 1;
sx_xlock(&sysctlmemlock);
}
CURVNET_SET(TD_TO_VNET(td));
for (;;) {
req.oldidx = 0;
req.newidx = 0;
error = sysctl_root(0, name, namelen, &req);
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)
{
/* Supply a default buffer size if none given. */
if (buf == NULL && length == 0)
length = 64;
s = sbuf_new(s, buf, length, SBUF_FIXEDLEN | SBUF_INCLUDENUL);
sbuf_set_drain(s, sbuf_sysctl_drain, req);
return (s);
}
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