xref: /freebsd-src/sys/sys/param.h (revision 7cc9e6ddbb1a6cd38b2f44d4dd9dfc890d2fc9d0)
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><0 if release branch, otherwise 1>xx
56  */
57 #undef __FreeBSD_version
58 #define __FreeBSD_version 502123	/* Master, propagated to newvers */
59 
60 #ifndef LOCORE
61 #include <sys/types.h>
62 #endif
63 
64 /*
65  * Machine-independent constants (some used in following include files).
66  * Redefined constants are from POSIX 1003.1 limits file.
67  *
68  * MAXCOMLEN should be >= sizeof(ac_comm) (see <acct.h>)
69  * MAXLOGNAME should be == UT_NAMESIZE+1 (see <utmp.h>)
70  */
71 #include <sys/syslimits.h>
72 
73 #define	MAXCOMLEN	19		/* max command name remembered */
74 #define	MAXINTERP	32		/* max interpreter file name length */
75 #define	MAXLOGNAME	17		/* max login name length (incl. NUL) */
76 #define	MAXUPRC		CHILD_MAX	/* max simultaneous processes */
77 #define	NCARGS		ARG_MAX		/* max bytes for an exec function */
78 #define	NGROUPS		NGROUPS_MAX	/* max number groups */
79 #define	NOFILE		OPEN_MAX	/* max open files per process */
80 #define	NOGROUP		65535		/* marker for empty group set member */
81 #define MAXHOSTNAMELEN	256		/* max hostname size */
82 #define SPECNAMELEN	63		/* max length of devicename */
83 
84 /* More types and definitions used throughout the kernel. */
85 #ifdef _KERNEL
86 #if (defined(BURN_BRIDGES) || __FreeBSD_version >= 600000) \
87 	&& defined(OBSOLETE_IN_6)
88 #error "This file contains obsolete code to be removed in 6.0-current"
89 #endif
90 #include <sys/cdefs.h>
91 #include <sys/errno.h>
92 #include <sys/time.h>
93 #include <sys/priority.h>
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 /*
145  * Some macros for units conversion
146  */
147 
148 /* clicks to bytes */
149 #ifndef ctob
150 #define ctob(x)	((x)<<PAGE_SHIFT)
151 #endif
152 
153 /* bytes to clicks */
154 #ifndef btoc
155 #define btoc(x)	(((vm_offset_t)(x)+PAGE_MASK)>>PAGE_SHIFT)
156 #endif
157 
158 /*
159  * btodb() is messy and perhaps slow because `bytes' may be an off_t.  We
160  * want to shift an unsigned type to avoid sign extension and we don't
161  * want to widen `bytes' unnecessarily.  Assume that the result fits in
162  * a daddr_t.
163  */
164 #ifndef btodb
165 #define btodb(bytes)	 		/* calculates (bytes / DEV_BSIZE) */ \
166 	(sizeof (bytes) > sizeof(long) \
167 	 ? (daddr_t)((unsigned long long)(bytes) >> DEV_BSHIFT) \
168 	 : (daddr_t)((unsigned long)(bytes) >> DEV_BSHIFT))
169 #endif
170 
171 #ifndef dbtob
172 #define dbtob(db)			/* calculates (db * DEV_BSIZE) */ \
173 	((off_t)(db) << DEV_BSHIFT)
174 #endif
175 
176 #endif /* _NO_NAMESPACE_POLLUTION */
177 
178 #define	PRIMASK	0x0ff
179 #define	PCATCH	0x100		/* OR'd with pri for tsleep to check signals */
180 #define	PDROP	0x200	/* OR'd with pri to stop re-entry of interlock mutex */
181 
182 #define	NZERO	0		/* default "nice" */
183 
184 #define	NBBY	8		/* number of bits in a byte */
185 #define	NBPW	sizeof(int)	/* number of bytes per word (integer) */
186 
187 #define	CMASK	022		/* default file mask: S_IWGRP|S_IWOTH */
188 
189 #define	NODEV	(dev_t)(-1)	/* non-existent device */
190 
191 #define	CBLOCK	128		/* Clist block size, must be a power of 2. */
192 #define CBQSIZE	(CBLOCK/NBBY)	/* Quote bytes/cblock - can do better. */
193 				/* Data chars/clist. */
194 #define	CBSIZE	(CBLOCK - sizeof(struct cblock *) - CBQSIZE)
195 #define	CROUND	(CBLOCK - 1)	/* Clist rounding. */
196 
197 /*
198  * File system parameters and macros.
199  *
200  * MAXBSIZE -	Filesystems are made out of blocks of at most MAXBSIZE bytes
201  *		per block.  MAXBSIZE may be made larger without effecting
202  *		any existing filesystems as long as it does not exceed MAXPHYS,
203  *		and may be made smaller at the risk of not being able to use
204  *		filesystems which require a block size exceeding MAXBSIZE.
205  *
206  * BKVASIZE -	Nominal buffer space per buffer, in bytes.  BKVASIZE is the
207  *		minimum KVM memory reservation the kernel is willing to make.
208  *		Filesystems can of course request smaller chunks.  Actual
209  *		backing memory uses a chunk size of a page (PAGE_SIZE).
210  *
211  *		If you make BKVASIZE too small you risk seriously fragmenting
212  *		the buffer KVM map which may slow things down a bit.  If you
213  *		make it too big the kernel will not be able to optimally use
214  *		the KVM memory reserved for the buffer cache and will wind
215  *		up with too-few buffers.
216  *
217  *		The default is 16384, roughly 2x the block size used by a
218  *		normal UFS filesystem.
219  */
220 #define MAXBSIZE	65536	/* must be power of 2 */
221 #define BKVASIZE	16384	/* must be power of 2 */
222 #define BKVAMASK	(BKVASIZE-1)
223 
224 /*
225  * MAXPATHLEN defines the longest permissible path length after expanding
226  * symbolic links. It is used to allocate a temporary buffer from the buffer
227  * pool in which to do the name expansion, hence should be a power of two,
228  * and must be less than or equal to MAXBSIZE.  MAXSYMLINKS defines the
229  * maximum number of symbolic links that may be expanded in a path name.
230  * It should be set high enough to allow all legitimate uses, but halt
231  * infinite loops reasonably quickly.
232  */
233 #define	MAXPATHLEN	PATH_MAX
234 #define MAXSYMLINKS	32
235 
236 /* Bit map related macros. */
237 #define	setbit(a,i)	((a)[(i)/NBBY] |= 1<<((i)%NBBY))
238 #define	clrbit(a,i)	((a)[(i)/NBBY] &= ~(1<<((i)%NBBY)))
239 #define	isset(a,i)	((a)[(i)/NBBY] & (1<<((i)%NBBY)))
240 #define	isclr(a,i)	(((a)[(i)/NBBY] & (1<<((i)%NBBY))) == 0)
241 
242 /* Macros for counting and rounding. */
243 #ifndef howmany
244 #define	howmany(x, y)	(((x)+((y)-1))/(y))
245 #endif
246 #define	rounddown(x, y)	(((x)/(y))*(y))
247 #define	roundup(x, y)	((((x)+((y)-1))/(y))*(y))  /* to any y */
248 #define	roundup2(x, y)	(((x)+((y)-1))&(~((y)-1))) /* if y is powers of two */
249 #define powerof2(x)	((((x)-1)&(x))==0)
250 
251 /* Macros for min/max. */
252 #define	MIN(a,b) (((a)<(b))?(a):(b))
253 #define	MAX(a,b) (((a)>(b))?(a):(b))
254 
255 #ifdef _KERNEL
256 /*
257  * Basic byte order function prototypes for non-inline functions.
258  */
259 #ifndef _BYTEORDER_PROTOTYPED
260 #define	_BYTEORDER_PROTOTYPED
261 __BEGIN_DECLS
262 __uint32_t	 htonl(__uint32_t);
263 __uint16_t	 htons(__uint16_t);
264 __uint32_t	 ntohl(__uint32_t);
265 __uint16_t	 ntohs(__uint16_t);
266 __END_DECLS
267 #endif
268 
269 #ifndef lint
270 #ifndef _BYTEORDER_FUNC_DEFINED
271 #define	_BYTEORDER_FUNC_DEFINED
272 #define	htonl(x)	__htonl(x)
273 #define	htons(x)	__htons(x)
274 #define	ntohl(x)	__ntohl(x)
275 #define	ntohs(x)	__ntohs(x)
276 #endif /* !_BYTEORDER_FUNC_DEFINED */
277 #endif /* lint */
278 #endif /* _KERNEL */
279 
280 /*
281  * Constants for setting the parameters of the kernel memory allocator.
282  *
283  * 2 ** MINBUCKET is the smallest unit of memory that will be
284  * allocated. It must be at least large enough to hold a pointer.
285  *
286  * Units of memory less or equal to MAXALLOCSAVE will permanently
287  * allocate physical memory; requests for these size pieces of
288  * memory are quite fast. Allocations greater than MAXALLOCSAVE must
289  * always allocate and free physical memory; requests for these
290  * size allocations should be done infrequently as they will be slow.
291  *
292  * Constraints: PAGE_SIZE <= MAXALLOCSAVE <= 2 ** (MINBUCKET + 14), and
293  * MAXALLOCSIZE must be a power of two.
294  */
295 #if defined(__alpha__) || defined(__ia64__) || defined(__sparc64__)
296 #define MINBUCKET	5		/* 5 => min allocation of 32 bytes */
297 #else
298 #define MINBUCKET	4		/* 4 => min allocation of 16 bytes */
299 #endif
300 #define MAXALLOCSAVE	(2 * PAGE_SIZE)
301 
302 /*
303  * Scale factor for scaled integers used to count %cpu time and load avgs.
304  *
305  * The number of CPU `tick's that map to a unique `%age' can be expressed
306  * by the formula (1 / (2 ^ (FSHIFT - 11))).  The maximum load average that
307  * can be calculated (assuming 32 bits) can be closely approximated using
308  * the formula (2 ^ (2 * (16 - FSHIFT))) for (FSHIFT < 15).
309  *
310  * For the scheduler to maintain a 1:1 mapping of CPU `tick' to `%age',
311  * FSHIFT must be at least 11; this gives us a maximum load avg of ~1024.
312  */
313 #define	FSHIFT	11		/* bits to right of fixed binary point */
314 #define FSCALE	(1<<FSHIFT)
315 
316 #define dbtoc(db)			/* calculates devblks to pages */ \
317 	((db + (ctodb(1) - 1)) >> (PAGE_SHIFT - DEV_BSHIFT))
318 
319 #define ctodb(db)			/* calculates pages to devblks */ \
320 	((db) << (PAGE_SHIFT - DEV_BSHIFT))
321 
322 #endif	/* _SYS_PARAM_H_ */
323