sysctl.h

RTEMS (Real-Time Executive for Multiprocessor Systems) is a free open source real-time operating sys

/*
 * Copyright (c) 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.
 *
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 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.
 *
 *	@(#)sysctl.h	8.1 (Berkeley) 6/2/93
 * $FreeBSD: src/sys/sys/sysctl.h,v 1.110 2002/10/20 22:48:08 phk Exp $
 */

#ifndef _SYS_SYSCTL_H_
#define	_SYS_SYSCTL_H_

#include <sys/queue.h>

struct thread;
/*
 * Definitions for sysctl call.  The sysctl call uses a hierarchical name
 * for objects that can be examined or modified.  The name is expressed as
 * a sequence of integers.  Like a file path name, the meaning of each
 * component depends on its place in the hierarchy.  The top-level and kern
 * identifiers are defined here, and other identifiers are defined in the
 * respective subsystem header files.
 */

#define CTL_MAXNAME	12	/* largest number of components supported */

/*
 * Each subsystem defined by sysctl defines a list of variables
 * for that subsystem. Each name is either a node with further
 * levels defined below it, or it is a leaf of some particular
 * type given below. Each sysctl level defines a set of name/type
 * pairs to be used by sysctl(1) in manipulating the subsystem.
 */
struct ctlname {
	char	*ctl_name;	/* subsystem name */
	int	ctl_type;	/* type of name */
};

#define CTLTYPE		0xf	/* Mask for the type */
#define	CTLTYPE_NODE	1	/* name is a node */
#define	CTLTYPE_INT	2	/* name describes an integer */
#define	CTLTYPE_STRING	3	/* name describes a string */
#define	CTLTYPE_QUAD	4	/* name describes a 64-bit number */
#define	CTLTYPE_OPAQUE	5	/* name describes a structure */
#define	CTLTYPE_STRUCT	CTLTYPE_OPAQUE	/* name describes a structure */
#define	CTLTYPE_UINT	6	/* name describes an unsigned integer */
#define	CTLTYPE_LONG	7	/* name describes a long */
#define	CTLTYPE_ULONG	8	/* name describes an unsigned long */

#define CTLFLAG_RD	0x80000000	/* Allow reads of variable */
#define CTLFLAG_WR	0x40000000	/* Allow writes to the variable */
#define CTLFLAG_RW	(CTLFLAG_RD|CTLFLAG_WR)
#define CTLFLAG_NOLOCK	0x20000000	/* XXX Don't Lock */
#define CTLFLAG_ANYBODY	0x10000000	/* All users can set this var */
#define CTLFLAG_SECURE	0x08000000	/* Permit set only if securelevel<=0 */
#define CTLFLAG_PRISON	0x04000000	/* Prisoned roots can fiddle */
#define CTLFLAG_DYN	0x02000000	/* Dynamic oid - can be freed */
#define CTLFLAG_SKIP	0x01000000	/* Skip this sysctl when listing */

/*
 * USE THIS instead of a hardwired number from the categories below
 * to get dynamically assigned sysctl entries using the linker-set
 * technology. This is the way nearly all new sysctl variables should
 * be implemented.
 * e.g. SYSCTL_INT(_parent, OID_AUTO, name, CTLFLAG_RW, &variable, 0, "");
 */ 
#define OID_AUTO	(-1)

/*
 * The starting number for dynamically-assigned entries.  WARNING!
 * ALL static sysctl entries should have numbers LESS than this!
 */
#define CTL_AUTO_START	0x100

#ifdef KERNEL
#define SYSCTL_HANDLER_ARGS struct sysctl_oid *oidp, void *arg1, int arg2, \
	struct sysctl_req *req

/*
 * This describes the access space for a sysctl request.  This is needed
 * so that we can use the interface from the kernel or from user-space.
 */
struct sysctl_req {
	struct thread	*td;		/* used for access checking */
	int		lock;
	void		*oldptr;
	size_t		oldlen;
	size_t		oldidx;
	int		(*oldfunc)(struct sysctl_req *, const void *, size_t);
	void		*newptr;
	size_t		newlen;
	size_t		newidx;
	int		(*newfunc)(struct sysctl_req *, void *, size_t);
};

SLIST_HEAD(sysctl_oid_list, sysctl_oid);

/*
 * This describes one "oid" in the MIB tree.  Potentially more nodes can
 * be hidden behind it, expanded by the handler.
 */
struct sysctl_oid {
	struct sysctl_oid_list *oid_parent;
	SLIST_ENTRY(sysctl_oid) oid_link;
	int		oid_number;
	u_int		oid_kind;
	void		*oid_arg1;
	int		oid_arg2;
	const char	*oid_name;
	int 		(*oid_handler)(SYSCTL_HANDLER_ARGS);
	const char	*oid_fmt;
	int		oid_refcnt;
	const char	*descr;
};

#define SYSCTL_IN(r, p, l) (r->newfunc)(r, p, l)
#define SYSCTL_OUT(r, p, l) (r->oldfunc)(r, p, l)

int sysctl_handle_int(SYSCTL_HANDLER_ARGS);
int sysctl_handle_long(SYSCTL_HANDLER_ARGS);
int sysctl_handle_intptr(SYSCTL_HANDLER_ARGS);
int sysctl_handle_string(SYSCTL_HANDLER_ARGS);
int sysctl_handle_opaque(SYSCTL_HANDLER_ARGS);

/*
 * These functions are used to add/remove an oid from the mib.
 */
void sysctl_register_oid(struct sysctl_oid *oidp);
void sysctl_unregister_oid(struct sysctl_oid *oidp);

/* Declare a static oid to allow child oids to be added to it. */
#define SYSCTL_DECL(name)					\
	extern struct sysctl_oid_list sysctl_##name##_children

/* Hide these in macros */
#define	SYSCTL_CHILDREN(oid_ptr) (struct sysctl_oid_list *) \
	(oid_ptr)->oid_arg1
#define	SYSCTL_STATIC_CHILDREN(oid_name) \
	(&sysctl_##oid_name##_children)

/* === Structs and macros related to context handling === */

/* All dynamically created sysctls can be tracked in a context list. */
struct sysctl_ctx_entry {
	struct sysctl_oid *entry;
	TAILQ_ENTRY(sysctl_ctx_entry) link;
};

TAILQ_HEAD(sysctl_ctx_list, sysctl_ctx_entry);

/* This constructs a "raw" MIB oid. */
#define SYSCTL_OID(parent, nbr, name, kind, a1, a2, handler, fmt, descr) \
	static struct sysctl_oid sysctl__##parent##_##name = {		 \
		&sysctl_##parent##_children, { 0 },			 \
		nbr, kind, a1, a2, #name, handler, fmt, 0, descr };	 \
	DATA_SET(sysctl_set, sysctl__##parent##_##name)

#define SYSCTL_ADD_OID(ctx, parent, nbr, name, kind, a1, a2, handler, fmt, descr) \
	sysctl_add_oid(ctx, parent, nbr, name, kind, a1, a2, handler, fmt, descr)

/* This constructs a node from which other oids can hang. */
#define SYSCTL_NODE(parent, nbr, name, access, handler, descr)		    \
	struct sysctl_oid_list sysctl_##parent##_##name##_children;	    \
	SYSCTL_OID(parent, nbr, name, CTLTYPE_NODE|(access),		    \
		   (void*)&sysctl_##parent##_##name##_children, 0, handler, \
		   "N", descr)

#define SYSCTL_ADD_NODE(ctx, parent, nbr, name, access, handler, descr)	    \
	sysctl_add_oid(ctx, parent, nbr, name, CTLTYPE_NODE|(access),	    \
	0, 0, handler, "N", descr)

/* Oid for a string.  len can be 0 to indicate '\0' termination. */
#define SYSCTL_STRING(parent, nbr, name, access, arg, len, descr) \
	SYSCTL_OID(parent, nbr, name, CTLTYPE_STRING|(access), \
		arg, len, sysctl_handle_string, "A", descr)

#define SYSCTL_ADD_STRING(ctx, parent, nbr, name, access, arg, len, descr)  \
	sysctl_add_oid(ctx, parent, nbr, name, CTLTYPE_STRING|(access),	    \
	arg, len, sysctl_handle_string, "A", descr)

/* Oid for an int.  If ptr is NULL, val is returned. */
#define SYSCTL_INT(parent, nbr, name, access, ptr, val, descr) \
	SYSCTL_OID(parent, nbr, name, CTLTYPE_INT|(access), \
		ptr, val, sysctl_handle_int, "I", descr)

#define SYSCTL_ADD_INT(ctx, parent, nbr, name, access, ptr, val, descr)	    \
	sysctl_add_oid(ctx, parent, nbr, name, CTLTYPE_INT|(access),	    \
	ptr, val, sysctl_handle_int, "I", descr)

/* Oid for an unsigned int.  If ptr is NULL, val is returned. */
#define SYSCTL_UINT(parent, nbr, name, access, ptr, val, descr) \
	SYSCTL_OID(parent, nbr, name, CTLTYPE_UINT|(access), \
		ptr, val, sysctl_handle_int, "IU", descr)

#define SYSCTL_ADD_UINT(ctx, parent, nbr, name, access, ptr, val, descr)    \
	sysctl_add_oid(ctx, parent, nbr, name, CTLTYPE_UINT|(access),	    \
	ptr, val, sysctl_handle_int, "IU", descr)

/* Oid for a long.  The pointer must be non NULL. */
#define SYSCTL_LONG(parent, nbr, name, access, ptr, val, descr) \
	SYSCTL_OID(parent, nbr, name, CTLTYPE_LONG|(access), \
		ptr, val, sysctl_handle_long, "L", descr)

#define SYSCTL_ADD_LONG(ctx, parent, nbr, name, access, ptr, descr)	    \
	sysctl_add_oid(ctx, parent, nbr, name, CTLTYPE_LONG|(access),	    \
	ptr, 0, sysctl_handle_long, "L", descr)

/* Oid for a long.  The pointer must be non NULL. */
#define SYSCTL_ULONG(parent, nbr, name, access, ptr, val, descr) \
	SYSCTL_OID(parent, nbr, name, CTLTYPE_ULONG|(access), \
		ptr, val, sysctl_handle_long, "LU", descr)

#define SYSCTL_ADD_ULONG(ctx, parent, nbr, name, access, ptr, descr)	    \
	sysctl_add_oid(ctx, parent, nbr, name, CTLTYPE_ULONG|(access),	    \
	ptr, 0, sysctl_handle_long, "LU", descr)

/* Oid for an opaque object.  Specified by a pointer and a length. */
#define SYSCTL_OPAQUE(parent, nbr, name, access, ptr, len, fmt, descr) \
	SYSCTL_OID(parent, nbr, name, CTLTYPE_OPAQUE|(access), \
		ptr, len, sysctl_handle_opaque, fmt, descr)

#define SYSCTL_ADD_OPAQUE(ctx, parent, nbr, name, access, ptr, len, fmt, descr)\
	sysctl_add_oid(ctx, parent, nbr, name, CTLTYPE_OPAQUE|(access),	    \
	ptr, len, sysctl_handle_opaque, fmt, descr)

/* Oid for a struct.  Specified by a pointer and a type. */
#define SYSCTL_STRUCT(parent, nbr, name, access, ptr, type, descr) \
	SYSCTL_OID(parent, nbr, name, CTLTYPE_OPAQUE|(access), \
		ptr, sizeof(struct type), sysctl_handle_opaque, \
		"S," #type, descr)

#define SYSCTL_ADD_STRUCT(ctx, parent, nbr, name, access, ptr, type, descr) \
	sysctl_add_oid(ctx, parent, nbr, name, CTLTYPE_OPAQUE|(access),	    \
	ptr, sizeof(struct type), sysctl_handle_opaque, "S," #type, descr)

/* Oid for a procedure.  Specified by a pointer and an arg. */
#define SYSCTL_PROC(parent, nbr, name, access, ptr, arg, handler, fmt, descr) \
	SYSCTL_OID(parent, nbr, name, (access), \
		ptr, arg, handler, fmt, descr)

#define SYSCTL_ADD_PROC(ctx, parent, nbr, name, access, ptr, arg, handler, fmt, descr) \
	sysctl_add_oid(ctx, parent, nbr, name, (access),			    \
	ptr, arg, handler, fmt, descr)

#endif /* KERNEL */

/*
 * Top-level identifiers
 */
#define	CTL_UNSPEC	0		/* unused */
#define	CTL_KERN	1		/* "high kernel": proc, limits */
#define	CTL_VM		2		/* virtual memory */
#define	CTL_VFS		3		/* filesystem, mount type is next */
#define	CTL_NET		4		/* network, see socket.h */
#define	CTL_DEBUG	5		/* debugging parameters */
#define	CTL_HW		6		/* generic cpu/io */
#define	CTL_MACHDEP	7		/* machine dependent */
#define	CTL_USER	8		/* user-level */
#define	CTL_P1003_1B	9		/* POSIX 1003.1B */
#define	CTL_MAXID	10		/* number of valid top-level ids */

#define CTL_NAMES { \
	{ 0, 0 }, \
	{ "kern", CTLTYPE_NODE }, \
	{ "vm", CTLTYPE_NODE }, \
	{ "vfs", CTLTYPE_NODE }, \
	{ "net", CTLTYPE_NODE }, \
	{ "debug", CTLTYPE_NODE }, \
	{ "hw", CTLTYPE_NODE }, \
	{ "machdep", CTLTYPE_NODE }, \
	{ "user", CTLTYPE_NODE }, \
	{ "p1003_1b", CTLTYPE_NODE }, \
}

/*
 * CTL_KERN identifiers