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freebsd/sys/kern/kern_sysctl.c
Kip Macy 8451d0dd78 In order to maximize the re-usability of kernel code in user space this 
patch modifies makesyscalls.sh to prefix all of the non-compatibility
calls (e.g. not linux_, freebsd32_) with sys_ and updates the kernel
entry points and all places in the code that use them. It also
fixes an additional name space collision between the kernel function
psignal and the libc function of the same name by renaming the kernel
psignal kern_psignal(). By introducing this change now we will ease future
MFCs that change syscalls.

Reviewed by:	rwatson
Approved by:	re (bz)
2011-09-16 13:58:51 +00:00

1669 lines
37 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.
* 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/capability.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);
struct sysctl_oid_list sysctl__children; /* root list */
static int sysctl_remove_oid_locked(struct sysctl_oid *oidp, int del,
int recurse);
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();
}
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);
}
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)
return (ENOTEMPTY);
error = sysctl_remove_oid_locked(p, del,
recurse);
if (error)
return (error);
}
if (del)
free(SYSCTL_CHILDREN(oidp), M_SYSCTLOID);
}
}
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((void *)(uintptr_t)(const void *)oidp->oid_descr, M_SYSCTLOID);
free((void *)(uintptr_t)(const void *)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;
ssize_t len;
char *newname;
/* 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_NEXT(oidp, oid_link) = NULL;
oidp->oid_number = number;
oidp->oid_refcnt = 1;
len = strlen(name);
newname = malloc(len + 1, M_SYSCTLOID, M_WAITOK);
bcopy(name, newname, len + 1);
newname[len] = '\0';
oidp->oid_name = newname;
oidp->oid_handler = handler;
oidp->oid_kind = CTLFLAG_DYN | kind;
if ((kind & CTLTYPE) == CTLTYPE_NODE) {
/* Allocate space for children */
SYSCTL_CHILDREN_SET(oidp, malloc(sizeof(struct sysctl_oid_list),
M_SYSCTLOID, M_WAITOK));
SLIST_INIT(SYSCTL_CHILDREN(oidp));
oidp->oid_arg2 = arg2;
} else {
oidp->oid_arg1 = arg1;
oidp->oid_arg2 = arg2;
}
oidp->oid_fmt = fmt;
if (descr) {
int len = strlen(descr) + 1;
oidp->oid_descr = malloc(len, M_SYSCTLOID, M_WAITOK);
if (oidp->oid_descr)
strcpy((char *)(uintptr_t)(const void *)oidp->oid_descr, descr);
}
/* 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)
{
ssize_t len;
char *newname;
void *oldname;
len = strlen(name);
newname = malloc(len + 1, M_SYSCTLOID, M_WAITOK);
bcopy(name, newname, len + 1);
newname[len] = '\0';
SYSCTL_XLOCK();
oldname = (void *)(uintptr_t)(const void *)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_ANY, 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(
oidp->oid_arg1, 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)
{
int i;
struct sysctl_oid *oidp;
struct sysctl_oid_list *lsp = &sysctl__children;
char *p;
SYSCTL_ASSERT_XLOCKED();
if (!*name)
return (ENOENT);
p = name + strlen(name) - 1 ;
if (*p == '.')
*p = '\0';
*len = 0;
for (p = name; *p && *p != '.'; p++)
;
i = *p;
if (i == '.')
*p = '\0';
oidp = SLIST_FIRST(lsp);
while (oidp && *len < CTL_MAXNAME) {
if (strcmp(name, oidp->oid_name)) {
oidp = SLIST_NEXT(oidp, oid_link);
continue;
}
*oid++ = oidp->oid_number;
(*len)++;
if (!i) {
if (oidpp)
*oidpp = oidp;
return (0);
}
if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE)
break;
if (oidp->oid_handler)
break;
lsp = SYSCTL_CHILDREN(oidp);
oidp = SLIST_FIRST(lsp);
name = p+1;
for (p = name; *p && *p != '.'; p++)
;
i = *p;
if (i == '.')
*p = '\0';
}
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. arg1 points to it.
*/
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)
return (EINVAL);
tmplong = *(long *)arg1;
#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);
#ifdef SCTL_MASK32
if (req->flags & SCTL_MASK32) {
error = SYSCTL_IN(req, &tmpint, sizeof(int));
*(long *)arg1 = (long)tmpint;
} else
#endif
error = SYSCTL_IN(req, arg1, sizeof(long));
return (error);
}
/*
* Handle a 64 bit int, signed or unsigned. arg1 points to it.
*/
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)
return (EINVAL);
tmpout = *(uint64_t *)arg1;
error = SYSCTL_OUT(req, &tmpout, sizeof(uint64_t));
if (error || !req->newptr)
return (error);
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)
{
int error=0;
char *tmparg;
size_t outlen;
/*
* Attempt to get a coherent snapshot by copying to a
* temporary kernel buffer.
*/
retry:
outlen = strlen((char *)arg1)+1;
tmparg = malloc(outlen, M_SYSCTLTMP, M_WAITOK);
if (strlcpy(tmparg, (char *)arg1, outlen) >= outlen) {
free(tmparg, M_SYSCTLTMP);
goto retry;
}
error = SYSCTL_OUT(req, tmparg, outlen);
free(tmparg, M_SYSCTLTMP);
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)
{
int error = 0;
size_t i, len, origidx;
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;
error = copyout(p, (char *)req->oldptr + origidx, i);
}
if (error)
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
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);
KFAIL_POINT_ERROR(_debug_fail_point, sysctl_running, error);
SYSCTL_XLOCK();
oid->oid_running--;
if (oid->oid_running == 0 && (oid->oid_kind & CTLFLAG_DYING) != 0)
wakeup(&oid->oid_running);
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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