freebsd-dev/sys/kern/kern_mib.c
Ed Schouten f3b86a5fd7 Mark most often used sysctl's as MPSAFE.
After running a `make buildkernel', I noticed most of the Giant locks in
sysctl are only caused by a very small amount of sysctl's:

- sysctl.name2oid. This one is locked by SYSCTL_LOCK, just like
  sysctl.oidfmt.

- kern.ident, kern.osrelease, kern.version, etc. These are just constant
  strings.

- kern.arandom, used by the stack protector. It is already protected by
  arc4_mtx.

I also saw the following sysctl's show up. Not as often as the ones
above, but still quite often:

- security.jail.jailed. Also mark security.jail.list as MPSAFE. They
  don't need locking or already use allprison_lock.

- kern.devname, used by devname(3), ttyname(3), etc.

This seems to reduce Giant locking inside sysctl by ~75% in my primitive
test setup.
2009-01-28 19:58:05 +00:00

472 lines
15 KiB
C

/*-
* 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_compat.h"
#include "opt_posix.h"
#include "opt_config.h"
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/sbuf.h>
#include <sys/systm.h>
#include <sys/sysctl.h>
#include <sys/proc.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/jail.h>
#include <sys/smp.h>
#include <sys/unistd.h>
#include <sys/vimage.h>
SYSCTL_NODE(, 0, sysctl, CTLFLAG_RW, 0,
"Sysctl internal magic");
SYSCTL_NODE(, CTL_KERN, kern, CTLFLAG_RW, 0,
"High kernel, proc, limits &c");
SYSCTL_NODE(, CTL_VM, vm, CTLFLAG_RW, 0,
"Virtual memory");
SYSCTL_NODE(, CTL_VFS, vfs, CTLFLAG_RW, 0,
"File system");
SYSCTL_NODE(, CTL_NET, net, CTLFLAG_RW, 0,
"Network, (see socket.h)");
SYSCTL_NODE(, CTL_DEBUG, debug, CTLFLAG_RW, 0,
"Debugging");
SYSCTL_NODE(_debug, OID_AUTO, sizeof, CTLFLAG_RW, 0,
"Sizeof various things");
SYSCTL_NODE(, CTL_HW, hw, CTLFLAG_RW, 0,
"hardware");
SYSCTL_NODE(, CTL_MACHDEP, machdep, CTLFLAG_RW, 0,
"machine dependent");
SYSCTL_NODE(, CTL_USER, user, CTLFLAG_RW, 0,
"user-level");
SYSCTL_NODE(, CTL_P1003_1B, p1003_1b, CTLFLAG_RW, 0,
"p1003_1b, (see p1003_1b.h)");
SYSCTL_NODE(, OID_AUTO, compat, CTLFLAG_RW, 0,
"Compatibility code");
SYSCTL_NODE(, OID_AUTO, security, CTLFLAG_RW, 0,
"Security");
#ifdef REGRESSION
SYSCTL_NODE(, OID_AUTO, regression, CTLFLAG_RW, 0,
"Regression test MIB");
#endif
SYSCTL_STRING(_kern, OID_AUTO, ident, CTLFLAG_RD|CTLFLAG_MPSAFE,
kern_ident, 0, "Kernel identifier");
SYSCTL_STRING(_kern, KERN_OSRELEASE, osrelease, CTLFLAG_RD|CTLFLAG_MPSAFE,
osrelease, 0, "Operating system release");
SYSCTL_INT(_kern, KERN_OSREV, osrevision, CTLFLAG_RD,
0, BSD, "Operating system revision");
SYSCTL_STRING(_kern, KERN_VERSION, version, CTLFLAG_RD|CTLFLAG_MPSAFE,
version, 0, "Kernel version");
SYSCTL_STRING(_kern, KERN_OSTYPE, ostype, CTLFLAG_RD|CTLFLAG_MPSAFE,
ostype, 0, "Operating system type");
/*
* NOTICE: The *userland* release date is available in
* /usr/include/osreldate.h
*/
SYSCTL_INT(_kern, KERN_OSRELDATE, osreldate, CTLFLAG_RD,
&osreldate, 0, "Kernel release date");
SYSCTL_INT(_kern, KERN_MAXPROC, maxproc, CTLFLAG_RDTUN,
&maxproc, 0, "Maximum number of processes");
SYSCTL_INT(_kern, KERN_MAXPROCPERUID, maxprocperuid, CTLFLAG_RW,
&maxprocperuid, 0, "Maximum processes allowed per userid");
SYSCTL_INT(_kern, OID_AUTO, maxusers, CTLFLAG_RDTUN,
&maxusers, 0, "Hint for kernel tuning");
SYSCTL_INT(_kern, KERN_ARGMAX, argmax, CTLFLAG_RD,
0, ARG_MAX, "Maximum bytes of argument to execve(2)");
SYSCTL_INT(_kern, KERN_POSIX1, posix1version, CTLFLAG_RD,
0, _POSIX_VERSION, "Version of POSIX attempting to comply to");
SYSCTL_INT(_kern, KERN_NGROUPS, ngroups, CTLFLAG_RD,
0, NGROUPS_MAX, "Maximum number of groups a user can belong to");
SYSCTL_INT(_kern, KERN_JOB_CONTROL, job_control, CTLFLAG_RD,
0, 1, "Whether job control is available");
#ifdef _POSIX_SAVED_IDS
SYSCTL_INT(_kern, KERN_SAVED_IDS, saved_ids, CTLFLAG_RD,
0, 1, "Whether saved set-group/user ID is available");
#else
SYSCTL_INT(_kern, KERN_SAVED_IDS, saved_ids, CTLFLAG_RD,
0, 0, "Whether saved set-group/user ID is available");
#endif
char kernelname[MAXPATHLEN] = "/kernel"; /* XXX bloat */
SYSCTL_STRING(_kern, KERN_BOOTFILE, bootfile, CTLFLAG_RW,
kernelname, sizeof kernelname, "Name of kernel file booted");
SYSCTL_INT(_hw, HW_NCPU, ncpu, CTLFLAG_RD,
&mp_ncpus, 0, "Number of active CPUs");
SYSCTL_INT(_hw, HW_BYTEORDER, byteorder, CTLFLAG_RD,
0, BYTE_ORDER, "System byte order");
SYSCTL_INT(_hw, HW_PAGESIZE, pagesize, CTLFLAG_RD,
0, PAGE_SIZE, "System memory page size");
static int
sysctl_kern_arnd(SYSCTL_HANDLER_ARGS)
{
char buf[256];
size_t len;
len = req->oldlen;
if (len > sizeof(buf))
len = sizeof(buf);
arc4rand(buf, len, 0);
return (SYSCTL_OUT(req, buf, len));
}
SYSCTL_PROC(_kern, KERN_ARND, arandom,
CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
sysctl_kern_arnd, "", "arc4rand");
static int
sysctl_hw_physmem(SYSCTL_HANDLER_ARGS)
{
u_long val;
val = ctob(physmem);
return (sysctl_handle_long(oidp, &val, 0, req));
}
SYSCTL_PROC(_hw, HW_PHYSMEM, physmem, CTLTYPE_ULONG | CTLFLAG_RD,
0, 0, sysctl_hw_physmem, "LU", "");
static int
sysctl_hw_realmem(SYSCTL_HANDLER_ARGS)
{
u_long val;
val = ctob(realmem);
return (sysctl_handle_long(oidp, &val, 0, req));
}
SYSCTL_PROC(_hw, HW_REALMEM, realmem, CTLTYPE_ULONG | CTLFLAG_RD,
0, 0, sysctl_hw_realmem, "LU", "");
static int
sysctl_hw_usermem(SYSCTL_HANDLER_ARGS)
{
u_long val;
val = ctob(physmem - cnt.v_wire_count);
return (sysctl_handle_long(oidp, &val, 0, req));
}
SYSCTL_PROC(_hw, HW_USERMEM, usermem, CTLTYPE_ULONG | CTLFLAG_RD,
0, 0, sysctl_hw_usermem, "LU", "");
SYSCTL_ULONG(_hw, OID_AUTO, availpages, CTLFLAG_RD, &physmem, 0, "");
static char machine_arch[] = MACHINE_ARCH;
SYSCTL_STRING(_hw, HW_MACHINE_ARCH, machine_arch, CTLFLAG_RD,
machine_arch, 0, "System architecture");
#ifndef VIMAGE
char hostname[MAXHOSTNAMELEN];
#endif
/*
* This mutex is used to protect the hostname and domainname variables, and
* perhaps in the future should also protect hostid, hostuid, and others.
*/
struct mtx hostname_mtx;
MTX_SYSINIT(hostname_mtx, &hostname_mtx, "hostname", MTX_DEF);
static int
sysctl_hostname(SYSCTL_HANDLER_ARGS)
{
INIT_VPROCG(TD_TO_VPROCG(req->td));
struct prison *pr;
char tmphostname[MAXHOSTNAMELEN];
int error;
pr = req->td->td_ucred->cr_prison;
if (pr != NULL) {
if (!jail_set_hostname_allowed && req->newptr)
return (EPERM);
/*
* Process is in jail, so make a local copy of jail
* hostname to get/set so we don't have to hold the jail
* mutex during the sysctl copyin/copyout activities.
*/
mtx_lock(&pr->pr_mtx);
bcopy(pr->pr_host, tmphostname, MAXHOSTNAMELEN);
mtx_unlock(&pr->pr_mtx);
error = sysctl_handle_string(oidp, tmphostname,
sizeof pr->pr_host, req);
if (req->newptr != NULL && error == 0) {
/*
* Copy the locally set hostname to the jail, if
* appropriate.
*/
mtx_lock(&pr->pr_mtx);
bcopy(tmphostname, pr->pr_host, MAXHOSTNAMELEN);
mtx_unlock(&pr->pr_mtx);
}
} else {
mtx_lock(&hostname_mtx);
bcopy(V_hostname, tmphostname, MAXHOSTNAMELEN);
mtx_unlock(&hostname_mtx);
error = sysctl_handle_string(oidp, tmphostname,
sizeof tmphostname, req);
if (req->newptr != NULL && error == 0) {
mtx_lock(&hostname_mtx);
bcopy(tmphostname, V_hostname, MAXHOSTNAMELEN);
mtx_unlock(&hostname_mtx);
}
}
return (error);
}
SYSCTL_PROC(_kern, KERN_HOSTNAME, hostname,
CTLTYPE_STRING|CTLFLAG_RW|CTLFLAG_PRISON|CTLFLAG_MPSAFE,
0, 0, sysctl_hostname, "A", "Hostname");
static int regression_securelevel_nonmonotonic = 0;
#ifdef REGRESSION
SYSCTL_INT(_regression, OID_AUTO, securelevel_nonmonotonic, CTLFLAG_RW,
&regression_securelevel_nonmonotonic, 0, "securelevel may be lowered");
#endif
int securelevel = -1;
static struct mtx securelevel_mtx;
MTX_SYSINIT(securelevel_lock, &securelevel_mtx, "securelevel mutex lock",
MTX_DEF);
static int
sysctl_kern_securelvl(SYSCTL_HANDLER_ARGS)
{
struct prison *pr;
int error, level;
pr = req->td->td_ucred->cr_prison;
/*
* If the process is in jail, return the maximum of the global and
* local levels; otherwise, return the global level. Perform a
* lockless read since the securelevel is an integer.
*/
if (pr != NULL)
level = imax(securelevel, pr->pr_securelevel);
else
level = securelevel;
error = sysctl_handle_int(oidp, &level, 0, req);
if (error || !req->newptr)
return (error);
/*
* Permit update only if the new securelevel exceeds the
* global level, and local level if any.
*/
if (pr != NULL) {
mtx_lock(&pr->pr_mtx);
if (!regression_securelevel_nonmonotonic &&
(level < imax(securelevel, pr->pr_securelevel))) {
mtx_unlock(&pr->pr_mtx);
return (EPERM);
}
pr->pr_securelevel = level;
mtx_unlock(&pr->pr_mtx);
} else {
mtx_lock(&securelevel_mtx);
if (!regression_securelevel_nonmonotonic &&
(level < securelevel)) {
mtx_unlock(&securelevel_mtx);
return (EPERM);
}
securelevel = level;
mtx_unlock(&securelevel_mtx);
}
return (error);
}
SYSCTL_PROC(_kern, KERN_SECURELVL, securelevel,
CTLTYPE_INT|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0, sysctl_kern_securelvl,
"I", "Current secure level");
#ifdef INCLUDE_CONFIG_FILE
/* Actual kernel configuration options. */
extern char kernconfstring[];
static int
sysctl_kern_config(SYSCTL_HANDLER_ARGS)
{
return (sysctl_handle_string(oidp, kernconfstring,
strlen(kernconfstring), req));
}
SYSCTL_PROC(_kern, OID_AUTO, conftxt, CTLTYPE_STRING|CTLFLAG_RW,
0, 0, sysctl_kern_config, "", "Kernel configuration file");
#endif
#ifndef VIMAGE
char domainname[MAXHOSTNAMELEN]; /* Protected by hostname_mtx. */
#endif
static int
sysctl_domainname(SYSCTL_HANDLER_ARGS)
{
char tmpdomainname[MAXHOSTNAMELEN];
int error;
mtx_lock(&hostname_mtx);
bcopy(V_domainname, tmpdomainname, MAXHOSTNAMELEN);
mtx_unlock(&hostname_mtx);
error = sysctl_handle_string(oidp, tmpdomainname,
sizeof tmpdomainname, req);
if (req->newptr != NULL && error == 0) {
mtx_lock(&hostname_mtx);
bcopy(tmpdomainname, V_domainname, MAXHOSTNAMELEN);
mtx_unlock(&hostname_mtx);
}
return (error);
}
SYSCTL_PROC(_kern, KERN_NISDOMAINNAME, domainname, CTLTYPE_STRING|CTLFLAG_RW,
0, 0, sysctl_domainname, "A", "Name of the current YP/NIS domain");
u_long hostid;
SYSCTL_ULONG(_kern, KERN_HOSTID, hostid, CTLFLAG_RW, &hostid, 0, "Host ID");
char hostuuid[64] = "00000000-0000-0000-0000-000000000000";
SYSCTL_STRING(_kern, KERN_HOSTUUID, hostuuid, CTLFLAG_RW, hostuuid,
sizeof(hostuuid), "Host UUID");
SYSCTL_NODE(_kern, OID_AUTO, features, CTLFLAG_RD, 0, "Kernel Features");
#ifdef COMPAT_FREEBSD4
FEATURE(compat_freebsd4, "Compatible with FreeBSD 4");
#endif
#ifdef COMPAT_FREEBSD5
FEATURE(compat_freebsd5, "Compatible with FreeBSD 5");
#endif
#ifdef COMPAT_FREEBSD6
FEATURE(compat_freebsd6, "Compatible with FreeBSD 6");
#endif
#ifdef COMPAT_FREEBSD7
FEATURE(compat_freebsd7, "Compatible with FreeBSD 7");
#endif
/*
* This is really cheating. These actually live in the libc, something
* which I'm not quite sure is a good idea anyway, but in order for
* getnext and friends to actually work, we define dummies here.
*/
SYSCTL_STRING(_user, USER_CS_PATH, cs_path, CTLFLAG_RD,
"", 0, "PATH that finds all the standard utilities");
SYSCTL_INT(_user, USER_BC_BASE_MAX, bc_base_max, CTLFLAG_RD,
0, 0, "Max ibase/obase values in bc(1)");
SYSCTL_INT(_user, USER_BC_DIM_MAX, bc_dim_max, CTLFLAG_RD,
0, 0, "Max array size in bc(1)");
SYSCTL_INT(_user, USER_BC_SCALE_MAX, bc_scale_max, CTLFLAG_RD,
0, 0, "Max scale value in bc(1)");
SYSCTL_INT(_user, USER_BC_STRING_MAX, bc_string_max, CTLFLAG_RD,
0, 0, "Max string length in bc(1)");
SYSCTL_INT(_user, USER_COLL_WEIGHTS_MAX, coll_weights_max, CTLFLAG_RD,
0, 0, "Maximum number of weights assigned to an LC_COLLATE locale entry");
SYSCTL_INT(_user, USER_EXPR_NEST_MAX, expr_nest_max, CTLFLAG_RD, 0, 0, "");
SYSCTL_INT(_user, USER_LINE_MAX, line_max, CTLFLAG_RD,
0, 0, "Max length (bytes) of a text-processing utility's input line");
SYSCTL_INT(_user, USER_RE_DUP_MAX, re_dup_max, CTLFLAG_RD,
0, 0, "Maximum number of repeats of a regexp permitted");
SYSCTL_INT(_user, USER_POSIX2_VERSION, posix2_version, CTLFLAG_RD,
0, 0,
"The version of POSIX 1003.2 with which the system attempts to comply");
SYSCTL_INT(_user, USER_POSIX2_C_BIND, posix2_c_bind, CTLFLAG_RD,
0, 0, "Whether C development supports the C bindings option");
SYSCTL_INT(_user, USER_POSIX2_C_DEV, posix2_c_dev, CTLFLAG_RD,
0, 0, "Whether system supports the C development utilities option");
SYSCTL_INT(_user, USER_POSIX2_CHAR_TERM, posix2_char_term, CTLFLAG_RD,
0, 0, "");
SYSCTL_INT(_user, USER_POSIX2_FORT_DEV, posix2_fort_dev, CTLFLAG_RD,
0, 0, "Whether system supports FORTRAN development utilities");
SYSCTL_INT(_user, USER_POSIX2_FORT_RUN, posix2_fort_run, CTLFLAG_RD,
0, 0, "Whether system supports FORTRAN runtime utilities");
SYSCTL_INT(_user, USER_POSIX2_LOCALEDEF, posix2_localedef, CTLFLAG_RD,
0, 0, "Whether system supports creation of locales");
SYSCTL_INT(_user, USER_POSIX2_SW_DEV, posix2_sw_dev, CTLFLAG_RD,
0, 0, "Whether system supports software development utilities");
SYSCTL_INT(_user, USER_POSIX2_UPE, posix2_upe, CTLFLAG_RD,
0, 0, "Whether system supports the user portability utilities");
SYSCTL_INT(_user, USER_STREAM_MAX, stream_max, CTLFLAG_RD,
0, 0, "Min Maximum number of streams a process may have open at one time");
SYSCTL_INT(_user, USER_TZNAME_MAX, tzname_max, CTLFLAG_RD,
0, 0, "Min Maximum number of types supported for timezone names");
#include <sys/vnode.h>
SYSCTL_INT(_debug_sizeof, OID_AUTO, vnode, CTLFLAG_RD,
0, sizeof(struct vnode), "sizeof(struct vnode)");
SYSCTL_INT(_debug_sizeof, OID_AUTO, proc, CTLFLAG_RD,
0, sizeof(struct proc), "sizeof(struct proc)");
#include <sys/bio.h>
#include <sys/buf.h>
SYSCTL_INT(_debug_sizeof, OID_AUTO, bio, CTLFLAG_RD,
0, sizeof(struct bio), "sizeof(struct bio)");
SYSCTL_INT(_debug_sizeof, OID_AUTO, buf, CTLFLAG_RD,
0, sizeof(struct buf), "sizeof(struct buf)");
#include <sys/user.h>
SYSCTL_INT(_debug_sizeof, OID_AUTO, kinfo_proc, CTLFLAG_RD,
0, sizeof(struct kinfo_proc), "sizeof(struct kinfo_proc)");
/* XXX compatibility, remove for 6.0 */
#include <sys/imgact.h>
#include <sys/imgact_elf.h>
SYSCTL_INT(_kern, OID_AUTO, fallback_elf_brand, CTLFLAG_RW,
&__elfN(fallback_brand), sizeof(__elfN(fallback_brand)),
"compatibility for kern.fallback_elf_brand");