xref: /freebsd-src/sys/sys/param.h (revision 2be1a816b9ff69588e55be0a84cbe2a31efc0f2f)
1 /*-
2  * Copyright (c) 1982, 1986, 1989, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  * (c) UNIX System Laboratories, Inc.
5  * All or some portions of this file are derived from material licensed
6  * to the University of California by American Telephone and Telegraph
7  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
8  * the permission of UNIX System Laboratories, Inc.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 4. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  *
34  *	@(#)param.h	8.3 (Berkeley) 4/4/95
35  * $FreeBSD$
36  */
37 
38 #ifndef _SYS_PARAM_H_
39 #define _SYS_PARAM_H_
40 
41 #include <sys/_null.h>
42 
43 #define	BSD	199506		/* System version (year & month). */
44 #define BSD4_3	1
45 #define BSD4_4	1
46 
47 /*
48  * __FreeBSD_version numbers are documented in the Porter's Handbook.
49  * If you bump the version for any reason, you should update the documentation
50  * there.
51  * Currently this lives here:
52  *
53  *	doc/en_US.ISO8859-1/books/porters-handbook/book.sgml
54  *
55  * scheme is:  <major><two digit minor>Rxx
56  *		'R' is 0 if release branch or x.0-CURRENT before RELENG_*_0
57  *		is created, otherwise 1.
58  */
59 #undef __FreeBSD_version
60 #define __FreeBSD_version 800036	/* Master, propagated to newvers */
61 
62 #ifndef LOCORE
63 #include <sys/types.h>
64 #endif
65 
66 /*
67  * Machine-independent constants (some used in following include files).
68  * Redefined constants are from POSIX 1003.1 limits file.
69  *
70  * MAXCOMLEN should be >= sizeof(ac_comm) (see <acct.h>)
71  * MAXLOGNAME should be == UT_NAMESIZE+1 (see <utmp.h>)
72  */
73 #include <sys/syslimits.h>
74 
75 #define	MAXCOMLEN	19		/* max command name remembered */
76 #define	MAXINTERP	32		/* max interpreter file name length */
77 #define	MAXLOGNAME	17		/* max login name length (incl. NUL) */
78 #define	MAXUPRC		CHILD_MAX	/* max simultaneous processes */
79 #define	NCARGS		ARG_MAX		/* max bytes for an exec function */
80 #define	NGROUPS		NGROUPS_MAX	/* max number groups */
81 #define	NOFILE		OPEN_MAX	/* max open files per process */
82 #define	NOGROUP		65535		/* marker for empty group set member */
83 #define MAXHOSTNAMELEN	256		/* max hostname size */
84 #define SPECNAMELEN	63		/* max length of devicename */
85 
86 /* More types and definitions used throughout the kernel. */
87 #ifdef _KERNEL
88 #include <sys/cdefs.h>
89 #include <sys/errno.h>
90 #ifndef LOCORE
91 #include <sys/time.h>
92 #include <sys/priority.h>
93 #endif
94 
95 #define	FALSE	0
96 #define	TRUE	1
97 #endif
98 
99 #ifndef _KERNEL
100 /* Signals. */
101 #include <sys/signal.h>
102 #endif
103 
104 /* Machine type dependent parameters. */
105 #include <machine/param.h>
106 #ifndef _KERNEL
107 #include <sys/limits.h>
108 #endif
109 
110 #ifndef _NO_NAMESPACE_POLLUTION
111 
112 #ifndef DEV_BSHIFT
113 #define	DEV_BSHIFT	9		/* log2(DEV_BSIZE) */
114 #endif
115 #define	DEV_BSIZE	(1<<DEV_BSHIFT)
116 
117 #ifndef BLKDEV_IOSIZE
118 #define BLKDEV_IOSIZE  PAGE_SIZE	/* default block device I/O size */
119 #endif
120 #ifndef DFLTPHYS
121 #define DFLTPHYS	(64 * 1024)	/* default max raw I/O transfer size */
122 #endif
123 #ifndef MAXPHYS
124 #define MAXPHYS		(128 * 1024)	/* max raw I/O transfer size */
125 #endif
126 #ifndef MAXDUMPPGS
127 #define MAXDUMPPGS	(DFLTPHYS/PAGE_SIZE)
128 #endif
129 
130 /*
131  * Constants related to network buffer management.
132  * MCLBYTES must be no larger than PAGE_SIZE.
133  */
134 #ifndef	MSIZE
135 #define MSIZE		256		/* size of an mbuf */
136 #endif	/* MSIZE */
137 
138 #ifndef	MCLSHIFT
139 #define MCLSHIFT	11		/* convert bytes to mbuf clusters */
140 #endif	/* MCLSHIFT */
141 
142 #define MCLBYTES	(1 << MCLSHIFT)	/* size of an mbuf cluster */
143 
144 #define	MJUMPAGESIZE	PAGE_SIZE	/* jumbo cluster 4k */
145 #define	MJUM9BYTES	(9 * 1024)	/* jumbo cluster 9k */
146 #define	MJUM16BYTES	(16 * 1024)	/* jumbo cluster 16k */
147 
148 /*
149  * Some macros for units conversion
150  */
151 
152 /* clicks to bytes */
153 #ifndef ctob
154 #define ctob(x)	((x)<<PAGE_SHIFT)
155 #endif
156 
157 /* bytes to clicks */
158 #ifndef btoc
159 #define btoc(x)	(((vm_offset_t)(x)+PAGE_MASK)>>PAGE_SHIFT)
160 #endif
161 
162 /*
163  * btodb() is messy and perhaps slow because `bytes' may be an off_t.  We
164  * want to shift an unsigned type to avoid sign extension and we don't
165  * want to widen `bytes' unnecessarily.  Assume that the result fits in
166  * a daddr_t.
167  */
168 #ifndef btodb
169 #define btodb(bytes)	 		/* calculates (bytes / DEV_BSIZE) */ \
170 	(sizeof (bytes) > sizeof(long) \
171 	 ? (daddr_t)((unsigned long long)(bytes) >> DEV_BSHIFT) \
172 	 : (daddr_t)((unsigned long)(bytes) >> DEV_BSHIFT))
173 #endif
174 
175 #ifndef dbtob
176 #define dbtob(db)			/* calculates (db * DEV_BSIZE) */ \
177 	((off_t)(db) << DEV_BSHIFT)
178 #endif
179 
180 #endif /* _NO_NAMESPACE_POLLUTION */
181 
182 #define	PRIMASK	0x0ff
183 #define	PCATCH	0x100		/* OR'd with pri for tsleep to check signals */
184 #define	PDROP	0x200	/* OR'd with pri to stop re-entry of interlock mutex */
185 
186 #define	NZERO	0		/* default "nice" */
187 
188 #define	NBBY	8		/* number of bits in a byte */
189 #define	NBPW	sizeof(int)	/* number of bytes per word (integer) */
190 
191 #define	CMASK	022		/* default file mask: S_IWGRP|S_IWOTH */
192 
193 #define	NODEV	(dev_t)(-1)	/* non-existent device */
194 
195 #define	CBLOCK	128		/* Clist block size, must be a power of 2. */
196 #define CBQSIZE	(CBLOCK/NBBY)	/* Quote bytes/cblock - can do better. */
197 				/* Data chars/clist. */
198 #define	CBSIZE	(CBLOCK - sizeof(struct cblock *) - CBQSIZE)
199 #define	CROUND	(CBLOCK - 1)	/* Clist rounding. */
200 
201 /*
202  * File system parameters and macros.
203  *
204  * MAXBSIZE -	Filesystems are made out of blocks of at most MAXBSIZE bytes
205  *		per block.  MAXBSIZE may be made larger without effecting
206  *		any existing filesystems as long as it does not exceed MAXPHYS,
207  *		and may be made smaller at the risk of not being able to use
208  *		filesystems which require a block size exceeding MAXBSIZE.
209  *
210  * BKVASIZE -	Nominal buffer space per buffer, in bytes.  BKVASIZE is the
211  *		minimum KVM memory reservation the kernel is willing to make.
212  *		Filesystems can of course request smaller chunks.  Actual
213  *		backing memory uses a chunk size of a page (PAGE_SIZE).
214  *
215  *		If you make BKVASIZE too small you risk seriously fragmenting
216  *		the buffer KVM map which may slow things down a bit.  If you
217  *		make it too big the kernel will not be able to optimally use
218  *		the KVM memory reserved for the buffer cache and will wind
219  *		up with too-few buffers.
220  *
221  *		The default is 16384, roughly 2x the block size used by a
222  *		normal UFS filesystem.
223  */
224 #define MAXBSIZE	65536	/* must be power of 2 */
225 #define BKVASIZE	16384	/* must be power of 2 */
226 #define BKVAMASK	(BKVASIZE-1)
227 
228 /*
229  * MAXPATHLEN defines the longest permissible path length after expanding
230  * symbolic links. It is used to allocate a temporary buffer from the buffer
231  * pool in which to do the name expansion, hence should be a power of two,
232  * and must be less than or equal to MAXBSIZE.  MAXSYMLINKS defines the
233  * maximum number of symbolic links that may be expanded in a path name.
234  * It should be set high enough to allow all legitimate uses, but halt
235  * infinite loops reasonably quickly.
236  */
237 #define	MAXPATHLEN	PATH_MAX
238 #define MAXSYMLINKS	32
239 
240 /* Bit map related macros. */
241 #define	setbit(a,i)	(((unsigned char *)(a))[(i)/NBBY] |= 1<<((i)%NBBY))
242 #define	clrbit(a,i)	(((unsigned char *)(a))[(i)/NBBY] &= ~(1<<((i)%NBBY)))
243 #define	isset(a,i)							\
244 	(((const unsigned char *)(a))[(i)/NBBY] & (1<<((i)%NBBY)))
245 #define	isclr(a,i)							\
246 	((((const unsigned char *)(a))[(i)/NBBY] & (1<<((i)%NBBY))) == 0)
247 
248 /* Macros for counting and rounding. */
249 #ifndef howmany
250 #define	howmany(x, y)	(((x)+((y)-1))/(y))
251 #endif
252 #define	rounddown(x, y)	(((x)/(y))*(y))
253 #define	roundup(x, y)	((((x)+((y)-1))/(y))*(y))  /* to any y */
254 #define	roundup2(x, y)	(((x)+((y)-1))&(~((y)-1))) /* if y is powers of two */
255 #define powerof2(x)	((((x)-1)&(x))==0)
256 
257 /* Macros for min/max. */
258 #define	MIN(a,b) (((a)<(b))?(a):(b))
259 #define	MAX(a,b) (((a)>(b))?(a):(b))
260 
261 #ifdef _KERNEL
262 /*
263  * Basic byte order function prototypes for non-inline functions.
264  */
265 #ifndef LOCORE
266 #ifndef _BYTEORDER_PROTOTYPED
267 #define	_BYTEORDER_PROTOTYPED
268 __BEGIN_DECLS
269 __uint32_t	 htonl(__uint32_t);
270 __uint16_t	 htons(__uint16_t);
271 __uint32_t	 ntohl(__uint32_t);
272 __uint16_t	 ntohs(__uint16_t);
273 __END_DECLS
274 #endif
275 #endif
276 
277 #ifndef lint
278 #ifndef _BYTEORDER_FUNC_DEFINED
279 #define	_BYTEORDER_FUNC_DEFINED
280 #define	htonl(x)	__htonl(x)
281 #define	htons(x)	__htons(x)
282 #define	ntohl(x)	__ntohl(x)
283 #define	ntohs(x)	__ntohs(x)
284 #endif /* !_BYTEORDER_FUNC_DEFINED */
285 #endif /* lint */
286 #endif /* _KERNEL */
287 
288 /*
289  * Scale factor for scaled integers used to count %cpu time and load avgs.
290  *
291  * The number of CPU `tick's that map to a unique `%age' can be expressed
292  * by the formula (1 / (2 ^ (FSHIFT - 11))).  The maximum load average that
293  * can be calculated (assuming 32 bits) can be closely approximated using
294  * the formula (2 ^ (2 * (16 - FSHIFT))) for (FSHIFT < 15).
295  *
296  * For the scheduler to maintain a 1:1 mapping of CPU `tick' to `%age',
297  * FSHIFT must be at least 11; this gives us a maximum load avg of ~1024.
298  */
299 #define	FSHIFT	11		/* bits to right of fixed binary point */
300 #define FSCALE	(1<<FSHIFT)
301 
302 #define dbtoc(db)			/* calculates devblks to pages */ \
303 	((db + (ctodb(1) - 1)) >> (PAGE_SHIFT - DEV_BSHIFT))
304 
305 #define ctodb(db)			/* calculates pages to devblks */ \
306 	((db) << (PAGE_SHIFT - DEV_BSHIFT))
307 
308 #endif	/* _SYS_PARAM_H_ */
309