freebsd-dev/sbin/newfs/mkfs.c
Poul-Henning Kamp 80f86e526b A more complete removal of MFS related code.
XXX: This program badly needs a style(9) + BDECFLAGS treatment.
2001-05-29 19:40:39 +00:00

1402 lines
37 KiB
C

/*
* Copyright (c) 1980, 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* 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.
*/
#ifndef lint
#if 0
static char sccsid[] = "@(#)mkfs.c 8.11 (Berkeley) 5/3/95";
#endif
static const char rcsid[] =
"$FreeBSD$";
#endif /* not lint */
#include <err.h>
#include <signal.h>
#include <string.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/param.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/resource.h>
#include <sys/stat.h>
#include <ufs/ufs/dinode.h>
#include <ufs/ufs/dir.h>
#include <ufs/ffs/fs.h>
#include <sys/disklabel.h>
#include <sys/file.h>
#include <sys/mman.h>
#include <sys/ioctl.h>
#ifndef STANDALONE
#include <stdlib.h>
#else
extern int atoi __P((char *));
extern char * getenv __P((char *));
#endif
#ifdef FSIRAND
extern long random __P((void));
extern void srandomdev __P((void));
#endif
/*
* make file system for cylinder-group style file systems
*/
/*
* We limit the size of the inode map to be no more than a
* third of the cylinder group space, since we must leave at
* least an equal amount of space for the block map.
*
* N.B.: MAXIPG must be a multiple of INOPB(fs).
*/
#define MAXIPG(fs) roundup((fs)->fs_bsize * NBBY / 3, INOPB(fs))
#define UMASK 0755
#define MAXINOPB (MAXBSIZE / sizeof(struct dinode))
#define POWEROF2(num) (((num) & ((num) - 1)) == 0)
/*
* variables set up by front end.
*/
extern int Nflag; /* run mkfs without writing file system */
extern int Oflag; /* format as an 4.3BSD file system */
extern int Uflag; /* enable soft updates for file system */
extern int fssize; /* file system size */
extern int ntracks; /* # tracks/cylinder */
extern int nsectors; /* # sectors/track */
extern int nphyssectors; /* # sectors/track including spares */
extern int secpercyl; /* sectors per cylinder */
extern int sectorsize; /* bytes/sector */
extern int realsectorsize; /* bytes/sector in hardware*/
extern int rpm; /* revolutions/minute of drive */
extern int interleave; /* hardware sector interleave */
extern int trackskew; /* sector 0 skew, per track */
extern int fsize; /* fragment size */
extern int bsize; /* block size */
extern int cpg; /* cylinders/cylinder group */
extern int cpgflg; /* cylinders/cylinder group flag was given */
extern int minfree; /* free space threshold */
extern int opt; /* optimization preference (space or time) */
extern int density; /* number of bytes per inode */
extern int maxcontig; /* max contiguous blocks to allocate */
extern int rotdelay; /* rotational delay between blocks */
extern int maxbpg; /* maximum blocks per file in a cyl group */
extern int nrpos; /* # of distinguished rotational positions */
extern int bbsize; /* boot block size */
extern int sbsize; /* superblock size */
extern int avgfilesize; /* expected average file size */
extern int avgfilesperdir; /* expected number of files per directory */
extern u_long memleft; /* virtual memory available */
extern caddr_t membase; /* start address of memory based filesystem */
extern char * filename;
union {
struct fs fs;
char pad[SBSIZE];
} fsun;
#define sblock fsun.fs
struct csum *fscs;
union {
struct cg cg;
char pad[MAXBSIZE];
} cgun;
#define acg cgun.cg
struct dinode zino[MAXBSIZE / sizeof(struct dinode)];
int fsi, fso;
#ifdef FSIRAND
int randinit;
#endif
daddr_t alloc();
long calcipg();
static int charsperline();
void clrblock __P((struct fs *, unsigned char *, int));
void fsinit __P((time_t));
void initcg __P((int, time_t));
int isblock __P((struct fs *, unsigned char *, int));
void iput __P((struct dinode *, ino_t));
int makedir __P((struct direct *, int));
void rdfs __P((daddr_t, int, char *));
void setblock __P((struct fs *, unsigned char *, int));
void wtfs __P((daddr_t, int, char *));
void wtfsflush __P((void));
#ifndef STANDALONE
#else
void free __P((char *));
char * calloc __P((u_long, u_long));
caddr_t malloc __P((u_long));
caddr_t realloc __P((char *, u_long));
#endif
void
mkfs(pp, fsys, fi, fo)
struct partition *pp;
char *fsys;
int fi, fo;
{
register long i, mincpc, mincpg, inospercg;
long cylno, rpos, blk, j, warn = 0;
long used, mincpgcnt, bpcg;
off_t usedb;
long mapcramped, inodecramped;
long postblsize, rotblsize, totalsbsize;
time_t utime;
quad_t sizepb;
int width;
char tmpbuf[100]; /* XXX this will break in about 2,500 years */
#ifndef STANDALONE
time(&utime);
#endif
#ifdef FSIRAND
if (!randinit) {
randinit = 1;
srandomdev();
}
#endif
fsi = fi;
fso = fo;
if (Oflag) {
sblock.fs_inodefmt = FS_42INODEFMT;
sblock.fs_maxsymlinklen = 0;
} else {
sblock.fs_inodefmt = FS_44INODEFMT;
sblock.fs_maxsymlinklen = MAXSYMLINKLEN;
}
if (Uflag)
sblock.fs_flags |= FS_DOSOFTDEP;
/*
* Validate the given file system size.
* Verify that its last block can actually be accessed.
*/
if (fssize <= 0)
printf("preposterous size %d\n", fssize), exit(13);
wtfs(fssize - (realsectorsize / DEV_BSIZE), realsectorsize,
(char *)&sblock);
/*
* collect and verify the sector and track info
*/
sblock.fs_nsect = nsectors;
sblock.fs_ntrak = ntracks;
if (sblock.fs_ntrak <= 0)
printf("preposterous ntrak %d\n", sblock.fs_ntrak), exit(14);
if (sblock.fs_nsect <= 0)
printf("preposterous nsect %d\n", sblock.fs_nsect), exit(15);
/*
* collect and verify the filesystem density info
*/
sblock.fs_avgfilesize = avgfilesize;
sblock.fs_avgfpdir = avgfilesperdir;
if (sblock.fs_avgfilesize <= 0)
printf("illegal expected average file size %d\n",
sblock.fs_avgfilesize), exit(14);
if (sblock.fs_avgfpdir <= 0)
printf("illegal expected number of files per directory %d\n",
sblock.fs_avgfpdir), exit(15);
/*
* collect and verify the block and fragment sizes
*/
sblock.fs_bsize = bsize;
sblock.fs_fsize = fsize;
if (!POWEROF2(sblock.fs_bsize)) {
printf("block size must be a power of 2, not %d\n",
sblock.fs_bsize);
exit(16);
}
if (!POWEROF2(sblock.fs_fsize)) {
printf("fragment size must be a power of 2, not %d\n",
sblock.fs_fsize);
exit(17);
}
if (sblock.fs_fsize < sectorsize) {
printf("fragment size %d is too small, minimum is %d\n",
sblock.fs_fsize, sectorsize);
exit(18);
}
if (sblock.fs_bsize < MINBSIZE) {
printf("block size %d is too small, minimum is %d\n",
sblock.fs_bsize, MINBSIZE);
exit(19);
}
if (sblock.fs_bsize < sblock.fs_fsize) {
printf("block size (%d) cannot be smaller than fragment size (%d)\n",
sblock.fs_bsize, sblock.fs_fsize);
exit(20);
}
sblock.fs_bmask = ~(sblock.fs_bsize - 1);
sblock.fs_fmask = ~(sblock.fs_fsize - 1);
sblock.fs_qbmask = ~sblock.fs_bmask;
sblock.fs_qfmask = ~sblock.fs_fmask;
for (sblock.fs_bshift = 0, i = sblock.fs_bsize; i > 1; i >>= 1)
sblock.fs_bshift++;
for (sblock.fs_fshift = 0, i = sblock.fs_fsize; i > 1; i >>= 1)
sblock.fs_fshift++;
sblock.fs_frag = numfrags(&sblock, sblock.fs_bsize);
for (sblock.fs_fragshift = 0, i = sblock.fs_frag; i > 1; i >>= 1)
sblock.fs_fragshift++;
if (sblock.fs_frag > MAXFRAG) {
printf("fragment size %d is too small, minimum with block size %d is %d\n",
sblock.fs_fsize, sblock.fs_bsize,
sblock.fs_bsize / MAXFRAG);
exit(21);
}
sblock.fs_nrpos = nrpos;
sblock.fs_nindir = sblock.fs_bsize / sizeof(daddr_t);
sblock.fs_inopb = sblock.fs_bsize / sizeof(struct dinode);
sblock.fs_nspf = sblock.fs_fsize / sectorsize;
for (sblock.fs_fsbtodb = 0, i = NSPF(&sblock); i > 1; i >>= 1)
sblock.fs_fsbtodb++;
sblock.fs_sblkno =
roundup(howmany(bbsize + sbsize, sblock.fs_fsize), sblock.fs_frag);
sblock.fs_cblkno = (daddr_t)(sblock.fs_sblkno +
roundup(howmany(sbsize, sblock.fs_fsize), sblock.fs_frag));
sblock.fs_iblkno = sblock.fs_cblkno + sblock.fs_frag;
sblock.fs_cgoffset = roundup(
howmany(sblock.fs_nsect, NSPF(&sblock)), sblock.fs_frag);
for (sblock.fs_cgmask = 0xffffffff, i = sblock.fs_ntrak; i > 1; i >>= 1)
sblock.fs_cgmask <<= 1;
if (!POWEROF2(sblock.fs_ntrak))
sblock.fs_cgmask <<= 1;
sblock.fs_maxfilesize = sblock.fs_bsize * NDADDR - 1;
for (sizepb = sblock.fs_bsize, i = 0; i < NIADDR; i++) {
sizepb *= NINDIR(&sblock);
sblock.fs_maxfilesize += sizepb;
}
/*
* Validate specified/determined secpercyl
* and calculate minimum cylinders per group.
*/
sblock.fs_spc = secpercyl;
for (sblock.fs_cpc = NSPB(&sblock), i = sblock.fs_spc;
sblock.fs_cpc > 1 && (i & 1) == 0;
sblock.fs_cpc >>= 1, i >>= 1)
/* void */;
mincpc = sblock.fs_cpc;
bpcg = sblock.fs_spc * sectorsize;
inospercg = roundup(bpcg / sizeof(struct dinode), INOPB(&sblock));
if (inospercg > MAXIPG(&sblock))
inospercg = MAXIPG(&sblock);
used = (sblock.fs_iblkno + inospercg / INOPF(&sblock)) * NSPF(&sblock);
mincpgcnt = howmany(sblock.fs_cgoffset * (~sblock.fs_cgmask) + used,
sblock.fs_spc);
mincpg = roundup(mincpgcnt, mincpc);
/*
* Ensure that cylinder group with mincpg has enough space
* for block maps.
*/
sblock.fs_cpg = mincpg;
sblock.fs_ipg = inospercg;
if (maxcontig > 1)
sblock.fs_contigsumsize = MIN(maxcontig, FS_MAXCONTIG);
mapcramped = 0;
while (CGSIZE(&sblock) > sblock.fs_bsize) {
mapcramped = 1;
if (sblock.fs_bsize < MAXBSIZE) {
sblock.fs_bsize <<= 1;
if ((i & 1) == 0) {
i >>= 1;
} else {
sblock.fs_cpc <<= 1;
mincpc <<= 1;
mincpg = roundup(mincpgcnt, mincpc);
sblock.fs_cpg = mincpg;
}
sblock.fs_frag <<= 1;
sblock.fs_fragshift += 1;
if (sblock.fs_frag <= MAXFRAG)
continue;
}
if (sblock.fs_fsize == sblock.fs_bsize) {
printf("There is no block size that");
printf(" can support this disk\n");
exit(22);
}
sblock.fs_frag >>= 1;
sblock.fs_fragshift -= 1;
sblock.fs_fsize <<= 1;
sblock.fs_nspf <<= 1;
}
/*
* Ensure that cylinder group with mincpg has enough space for inodes.
*/
inodecramped = 0;
inospercg = calcipg(mincpg, bpcg, &usedb);
sblock.fs_ipg = inospercg;
while (inospercg > MAXIPG(&sblock)) {
inodecramped = 1;
if (mincpc == 1 || sblock.fs_frag == 1 ||
sblock.fs_bsize == MINBSIZE)
break;
printf("With a block size of %d %s %d\n", sblock.fs_bsize,
"minimum bytes per inode is",
(int)((mincpg * (off_t)bpcg - usedb)
/ MAXIPG(&sblock) + 1));
sblock.fs_bsize >>= 1;
sblock.fs_frag >>= 1;
sblock.fs_fragshift -= 1;
mincpc >>= 1;
sblock.fs_cpg = roundup(mincpgcnt, mincpc);
if (CGSIZE(&sblock) > sblock.fs_bsize) {
sblock.fs_bsize <<= 1;
break;
}
mincpg = sblock.fs_cpg;
inospercg = calcipg(mincpg, bpcg, &usedb);
sblock.fs_ipg = inospercg;
}
if (inodecramped) {
if (inospercg > MAXIPG(&sblock)) {
printf("Minimum bytes per inode is %d\n",
(int)((mincpg * (off_t)bpcg - usedb)
/ MAXIPG(&sblock) + 1));
} else if (!mapcramped) {
printf("With %d bytes per inode, ", density);
printf("minimum cylinders per group is %ld\n", mincpg);
}
}
if (mapcramped) {
printf("With %d sectors per cylinder, ", sblock.fs_spc);
printf("minimum cylinders per group is %ld\n", mincpg);
}
if (inodecramped || mapcramped) {
if (sblock.fs_bsize != bsize)
printf("%s to be changed from %d to %d\n",
"This requires the block size",
bsize, sblock.fs_bsize);
if (sblock.fs_fsize != fsize)
printf("\t%s to be changed from %d to %d\n",
"and the fragment size",
fsize, sblock.fs_fsize);
exit(23);
}
/*
* Calculate the number of cylinders per group
*/
sblock.fs_cpg = cpg;
if (sblock.fs_cpg % mincpc != 0) {
printf("%s groups must have a multiple of %ld cylinders\n",
cpgflg ? "Cylinder" : "Warning: cylinder", mincpc);
sblock.fs_cpg = roundup(sblock.fs_cpg, mincpc);
if (!cpgflg)
cpg = sblock.fs_cpg;
}
/*
* Must ensure there is enough space for inodes.
*/
sblock.fs_ipg = calcipg(sblock.fs_cpg, bpcg, &usedb);
while (sblock.fs_ipg > MAXIPG(&sblock)) {
inodecramped = 1;
sblock.fs_cpg -= mincpc;
sblock.fs_ipg = calcipg(sblock.fs_cpg, bpcg, &usedb);
}
/*
* Must ensure there is enough space to hold block map.
*/
while (CGSIZE(&sblock) > sblock.fs_bsize) {
mapcramped = 1;
sblock.fs_cpg -= mincpc;
sblock.fs_ipg = calcipg(sblock.fs_cpg, bpcg, &usedb);
}
sblock.fs_fpg = (sblock.fs_cpg * sblock.fs_spc) / NSPF(&sblock);
if ((sblock.fs_cpg * sblock.fs_spc) % NSPB(&sblock) != 0) {
printf("panic (fs_cpg * fs_spc) %% NSPF != 0");
exit(24);
}
if (sblock.fs_cpg < mincpg) {
printf("cylinder groups must have at least %ld cylinders\n",
mincpg);
exit(25);
} else if (sblock.fs_cpg != cpg) {
if (!cpgflg)
printf("Warning: ");
else if (!mapcramped && !inodecramped)
exit(26);
if (mapcramped && inodecramped)
printf("Block size and bytes per inode restrict");
else if (mapcramped)
printf("Block size restricts");
else
printf("Bytes per inode restrict");
printf(" cylinders per group to %d.\n", sblock.fs_cpg);
if (cpgflg)
exit(27);
}
sblock.fs_cgsize = fragroundup(&sblock, CGSIZE(&sblock));
/*
* Now have size for file system and nsect and ntrak.
* Determine number of cylinders and blocks in the file system.
*/
sblock.fs_size = fssize = dbtofsb(&sblock, fssize);
sblock.fs_ncyl = fssize * NSPF(&sblock) / sblock.fs_spc;
if (fssize * NSPF(&sblock) > sblock.fs_ncyl * sblock.fs_spc) {
sblock.fs_ncyl++;
warn = 1;
}
if (sblock.fs_ncyl < 1) {
printf("file systems must have at least one cylinder\n");
exit(28);
}
/*
* Determine feasability/values of rotational layout tables.
*
* The size of the rotational layout tables is limited by the
* size of the superblock, SBSIZE. The amount of space available
* for tables is calculated as (SBSIZE - sizeof (struct fs)).
* The size of these tables is inversely proportional to the block
* size of the file system. The size increases if sectors per track
* are not powers of two, because more cylinders must be described
* by the tables before the rotational pattern repeats (fs_cpc).
*/
sblock.fs_interleave = interleave;
sblock.fs_trackskew = trackskew;
sblock.fs_npsect = nphyssectors;
sblock.fs_postblformat = FS_DYNAMICPOSTBLFMT;
sblock.fs_sbsize = fragroundup(&sblock, sizeof(struct fs));
if (sblock.fs_sbsize > SBSIZE)
sblock.fs_sbsize = SBSIZE;
if (sblock.fs_ntrak == 1) {
sblock.fs_cpc = 0;
goto next;
}
postblsize = sblock.fs_nrpos * sblock.fs_cpc * sizeof(int16_t);
rotblsize = sblock.fs_cpc * sblock.fs_spc / NSPB(&sblock);
totalsbsize = sizeof(struct fs) + rotblsize;
if (sblock.fs_nrpos == 8 && sblock.fs_cpc <= 16) {
/* use old static table space */
sblock.fs_postbloff = (char *)(&sblock.fs_opostbl[0][0]) -
(char *)(&sblock.fs_firstfield);
sblock.fs_rotbloff = &sblock.fs_space[0] -
(u_char *)(&sblock.fs_firstfield);
} else {
/* use dynamic table space */
sblock.fs_postbloff = &sblock.fs_space[0] -
(u_char *)(&sblock.fs_firstfield);
sblock.fs_rotbloff = sblock.fs_postbloff + postblsize;
totalsbsize += postblsize;
}
if (totalsbsize > SBSIZE ||
sblock.fs_nsect > (1 << NBBY) * NSPB(&sblock)) {
printf("%s %s %d %s %d.%s",
"Warning: insufficient space in super block for\n",
"rotational layout tables with nsect", sblock.fs_nsect,
"and ntrak", sblock.fs_ntrak,
"\nFile system performance may be impaired.\n");
sblock.fs_cpc = 0;
goto next;
}
sblock.fs_sbsize = fragroundup(&sblock, totalsbsize);
if (sblock.fs_sbsize > SBSIZE)
sblock.fs_sbsize = SBSIZE;
/*
* calculate the available blocks for each rotational position
*/
for (cylno = 0; cylno < sblock.fs_cpc; cylno++)
for (rpos = 0; rpos < sblock.fs_nrpos; rpos++)
fs_postbl(&sblock, cylno)[rpos] = -1;
for (i = (rotblsize - 1) * sblock.fs_frag;
i >= 0; i -= sblock.fs_frag) {
cylno = cbtocylno(&sblock, i);
rpos = cbtorpos(&sblock, i);
blk = fragstoblks(&sblock, i);
if (fs_postbl(&sblock, cylno)[rpos] == -1)
fs_rotbl(&sblock)[blk] = 0;
else
fs_rotbl(&sblock)[blk] =
fs_postbl(&sblock, cylno)[rpos] - blk;
fs_postbl(&sblock, cylno)[rpos] = blk;
}
next:
/*
* Compute/validate number of cylinder groups.
*/
sblock.fs_ncg = sblock.fs_ncyl / sblock.fs_cpg;
if (sblock.fs_ncyl % sblock.fs_cpg)
sblock.fs_ncg++;
sblock.fs_dblkno = sblock.fs_iblkno + sblock.fs_ipg / INOPF(&sblock);
i = MIN(~sblock.fs_cgmask, sblock.fs_ncg - 1);
if (cgdmin(&sblock, i) - cgbase(&sblock, i) >= sblock.fs_fpg) {
printf("inode blocks/cyl group (%ld) >= data blocks (%ld)\n",
cgdmin(&sblock, i) - cgbase(&sblock, i) / sblock.fs_frag,
(long)(sblock.fs_fpg / sblock.fs_frag));
printf("number of cylinders per cylinder group (%d) %s.\n",
sblock.fs_cpg, "must be increased");
exit(29);
}
j = sblock.fs_ncg - 1;
if ((i = fssize - j * sblock.fs_fpg) < sblock.fs_fpg &&
cgdmin(&sblock, j) - cgbase(&sblock, j) > i) {
if (j == 0) {
printf("Filesystem must have at least %d sectors\n",
NSPF(&sblock) *
(cgdmin(&sblock, 0) + 3 * sblock.fs_frag));
exit(30);
}
printf(
"Warning: inode blocks/cyl group (%ld) >= data blocks (%ld) in last\n",
(cgdmin(&sblock, j) - cgbase(&sblock, j)) / sblock.fs_frag,
i / sblock.fs_frag);
printf(
" cylinder group. This implies %ld sector(s) cannot be allocated.\n",
i * NSPF(&sblock));
sblock.fs_ncg--;
sblock.fs_ncyl -= sblock.fs_ncyl % sblock.fs_cpg;
sblock.fs_size = fssize = sblock.fs_ncyl * sblock.fs_spc /
NSPF(&sblock);
warn = 0;
}
if (warn) {
printf("Warning: %d sector(s) in last cylinder unallocated\n",
sblock.fs_spc -
(fssize * NSPF(&sblock) - (sblock.fs_ncyl - 1)
* sblock.fs_spc));
}
/*
* fill in remaining fields of the super block
*/
sblock.fs_csaddr = cgdmin(&sblock, 0);
sblock.fs_cssize =
fragroundup(&sblock, sblock.fs_ncg * sizeof(struct csum));
/*
* The superblock fields 'fs_csmask' and 'fs_csshift' are no
* longer used. However, we still initialise them so that the
* filesystem remains compatible with old kernels.
*/
i = sblock.fs_bsize / sizeof(struct csum);
sblock.fs_csmask = ~(i - 1);
for (sblock.fs_csshift = 0; i > 1; i >>= 1)
sblock.fs_csshift++;
fscs = (struct csum *)calloc(1, sblock.fs_cssize);
if (fscs == NULL)
errx(31, "calloc failed");
sblock.fs_magic = FS_MAGIC;
sblock.fs_rotdelay = rotdelay;
sblock.fs_minfree = minfree;
sblock.fs_maxcontig = maxcontig;
sblock.fs_maxbpg = maxbpg;
sblock.fs_rps = rpm / 60;
sblock.fs_optim = opt;
sblock.fs_cgrotor = 0;
sblock.fs_cstotal.cs_ndir = 0;
sblock.fs_cstotal.cs_nbfree = 0;
sblock.fs_cstotal.cs_nifree = 0;
sblock.fs_cstotal.cs_nffree = 0;
sblock.fs_fmod = 0;
sblock.fs_ronly = 0;
sblock.fs_clean = 1;
#ifdef FSIRAND
sblock.fs_id[0] = (long)utime;
sblock.fs_id[1] = random();
#endif
/*
* Dump out summary information about file system.
*/
printf("%s:\t%d sectors in %d %s of %d tracks, %d sectors\n",
fsys, sblock.fs_size * NSPF(&sblock), sblock.fs_ncyl,
"cylinders", sblock.fs_ntrak, sblock.fs_nsect);
#define B2MBFACTOR (1 / (1024.0 * 1024.0))
printf(
"\t%.1fMB in %d cyl groups (%d c/g, %.2fMB/g, %d i/g)%s\n",
(float)sblock.fs_size * sblock.fs_fsize * B2MBFACTOR,
sblock.fs_ncg, sblock.fs_cpg,
(float)sblock.fs_fpg * sblock.fs_fsize * B2MBFACTOR,
sblock.fs_ipg,
sblock.fs_flags & FS_DOSOFTDEP ? " SOFTUPDATES" : "");
#undef B2MBFACTOR
/*
* Now build the cylinders group blocks and
* then print out indices of cylinder groups.
*/
printf("super-block backups (for fsck -b #) at:\n");
i = 0;
width = charsperline();
for (cylno = 0; cylno < sblock.fs_ncg; cylno++) {
initcg(cylno, utime);
j = snprintf(tmpbuf, sizeof(tmpbuf), " %ld%s",
fsbtodb(&sblock, cgsblock(&sblock, cylno)),
cylno < (sblock.fs_ncg-1) ? "," : "" );
if (i + j >= width) {
printf("\n");
i = 0;
}
i += j;
printf("%s", tmpbuf);
fflush(stdout);
}
printf("\n");
if (Nflag)
exit(0);
/*
* Now construct the initial file system,
* then write out the super-block.
*/
fsinit(utime);
sblock.fs_time = utime;
wtfs((int)SBOFF / sectorsize, sbsize, (char *)&sblock);
for (i = 0; i < sblock.fs_cssize; i += sblock.fs_bsize)
wtfs(fsbtodb(&sblock, sblock.fs_csaddr + numfrags(&sblock, i)),
sblock.fs_cssize - i < sblock.fs_bsize ?
sblock.fs_cssize - i : sblock.fs_bsize,
((char *)fscs) + i);
/*
* Write out the duplicate super blocks
*/
for (cylno = 0; cylno < sblock.fs_ncg; cylno++)
wtfs(fsbtodb(&sblock, cgsblock(&sblock, cylno)),
sbsize, (char *)&sblock);
wtfsflush();
/*
* Update information about this partion in pack
* label, to that it may be updated on disk.
*/
pp->p_fstype = FS_BSDFFS;
pp->p_fsize = sblock.fs_fsize;
pp->p_frag = sblock.fs_frag;
pp->p_cpg = sblock.fs_cpg;
}
/*
* Initialize a cylinder group.
*/
void
initcg(cylno, utime)
int cylno;
time_t utime;
{
daddr_t cbase, d, dlower, dupper, dmax, blkno;
long i;
register struct csum *cs;
#ifdef FSIRAND
long j;
#endif
/*
* Determine block bounds for cylinder group.
* Allow space for super block summary information in first
* cylinder group.
*/
cbase = cgbase(&sblock, cylno);
dmax = cbase + sblock.fs_fpg;
if (dmax > sblock.fs_size)
dmax = sblock.fs_size;
dlower = cgsblock(&sblock, cylno) - cbase;
dupper = cgdmin(&sblock, cylno) - cbase;
if (cylno == 0)
dupper += howmany(sblock.fs_cssize, sblock.fs_fsize);
cs = fscs + cylno;
memset(&acg, 0, sblock.fs_cgsize);
acg.cg_time = utime;
acg.cg_magic = CG_MAGIC;
acg.cg_cgx = cylno;
if (cylno == sblock.fs_ncg - 1)
acg.cg_ncyl = sblock.fs_ncyl % sblock.fs_cpg;
else
acg.cg_ncyl = sblock.fs_cpg;
acg.cg_niblk = sblock.fs_ipg;
acg.cg_ndblk = dmax - cbase;
if (sblock.fs_contigsumsize > 0)
acg.cg_nclusterblks = acg.cg_ndblk / sblock.fs_frag;
acg.cg_btotoff = &acg.cg_space[0] - (u_char *)(&acg.cg_firstfield);
acg.cg_boff = acg.cg_btotoff + sblock.fs_cpg * sizeof(int32_t);
acg.cg_iusedoff = acg.cg_boff +
sblock.fs_cpg * sblock.fs_nrpos * sizeof(u_int16_t);
acg.cg_freeoff = acg.cg_iusedoff + howmany(sblock.fs_ipg, NBBY);
if (sblock.fs_contigsumsize <= 0) {
acg.cg_nextfreeoff = acg.cg_freeoff +
howmany(sblock.fs_cpg * sblock.fs_spc / NSPF(&sblock), NBBY);
} else {
acg.cg_clustersumoff = acg.cg_freeoff + howmany
(sblock.fs_cpg * sblock.fs_spc / NSPF(&sblock), NBBY) -
sizeof(u_int32_t);
acg.cg_clustersumoff =
roundup(acg.cg_clustersumoff, sizeof(u_int32_t));
acg.cg_clusteroff = acg.cg_clustersumoff +
(sblock.fs_contigsumsize + 1) * sizeof(u_int32_t);
acg.cg_nextfreeoff = acg.cg_clusteroff + howmany
(sblock.fs_cpg * sblock.fs_spc / NSPB(&sblock), NBBY);
}
if (acg.cg_nextfreeoff - (long)(&acg.cg_firstfield) > sblock.fs_cgsize) {
printf("Panic: cylinder group too big\n");
exit(37);
}
acg.cg_cs.cs_nifree += sblock.fs_ipg;
if (cylno == 0)
for (i = 0; i < ROOTINO; i++) {
setbit(cg_inosused(&acg), i);
acg.cg_cs.cs_nifree--;
}
for (i = 0; i < sblock.fs_ipg / INOPF(&sblock); i += sblock.fs_frag) {
#ifdef FSIRAND
for (j = 0; j < sblock.fs_bsize / sizeof(struct dinode); j++)
zino[j].di_gen = random();
#endif
wtfs(fsbtodb(&sblock, cgimin(&sblock, cylno) + i),
sblock.fs_bsize, (char *)zino);
}
if (cylno > 0) {
/*
* In cylno 0, beginning space is reserved
* for boot and super blocks.
*/
for (d = 0; d < dlower; d += sblock.fs_frag) {
blkno = d / sblock.fs_frag;
setblock(&sblock, cg_blksfree(&acg), blkno);
if (sblock.fs_contigsumsize > 0)
setbit(cg_clustersfree(&acg), blkno);
acg.cg_cs.cs_nbfree++;
cg_blktot(&acg)[cbtocylno(&sblock, d)]++;
cg_blks(&sblock, &acg, cbtocylno(&sblock, d))
[cbtorpos(&sblock, d)]++;
}
sblock.fs_dsize += dlower;
}
sblock.fs_dsize += acg.cg_ndblk - dupper;
if ((i = dupper % sblock.fs_frag)) {
acg.cg_frsum[sblock.fs_frag - i]++;
for (d = dupper + sblock.fs_frag - i; dupper < d; dupper++) {
setbit(cg_blksfree(&acg), dupper);
acg.cg_cs.cs_nffree++;
}
}
for (d = dupper; d + sblock.fs_frag <= dmax - cbase; ) {
blkno = d / sblock.fs_frag;
setblock(&sblock, cg_blksfree(&acg), blkno);
if (sblock.fs_contigsumsize > 0)
setbit(cg_clustersfree(&acg), blkno);
acg.cg_cs.cs_nbfree++;
cg_blktot(&acg)[cbtocylno(&sblock, d)]++;
cg_blks(&sblock, &acg, cbtocylno(&sblock, d))
[cbtorpos(&sblock, d)]++;
d += sblock.fs_frag;
}
if (d < dmax - cbase) {
acg.cg_frsum[dmax - cbase - d]++;
for (; d < dmax - cbase; d++) {
setbit(cg_blksfree(&acg), d);
acg.cg_cs.cs_nffree++;
}
}
if (sblock.fs_contigsumsize > 0) {
int32_t *sump = cg_clustersum(&acg);
u_char *mapp = cg_clustersfree(&acg);
int map = *mapp++;
int bit = 1;
int run = 0;
for (i = 0; i < acg.cg_nclusterblks; i++) {
if ((map & bit) != 0) {
run++;
} else if (run != 0) {
if (run > sblock.fs_contigsumsize)
run = sblock.fs_contigsumsize;
sump[run]++;
run = 0;
}
if ((i & (NBBY - 1)) != (NBBY - 1)) {
bit <<= 1;
} else {
map = *mapp++;
bit = 1;
}
}
if (run != 0) {
if (run > sblock.fs_contigsumsize)
run = sblock.fs_contigsumsize;
sump[run]++;
}
}
sblock.fs_cstotal.cs_ndir += acg.cg_cs.cs_ndir;
sblock.fs_cstotal.cs_nffree += acg.cg_cs.cs_nffree;
sblock.fs_cstotal.cs_nbfree += acg.cg_cs.cs_nbfree;
sblock.fs_cstotal.cs_nifree += acg.cg_cs.cs_nifree;
*cs = acg.cg_cs;
wtfs(fsbtodb(&sblock, cgtod(&sblock, cylno)),
sblock.fs_bsize, (char *)&acg);
}
/*
* initialize the file system
*/
struct dinode node;
#ifdef LOSTDIR
#define PREDEFDIR 3
#else
#define PREDEFDIR 2
#endif
struct direct root_dir[] = {
{ ROOTINO, sizeof(struct direct), DT_DIR, 1, "." },
{ ROOTINO, sizeof(struct direct), DT_DIR, 2, ".." },
#ifdef LOSTDIR
{ LOSTFOUNDINO, sizeof(struct direct), DT_DIR, 10, "lost+found" },
#endif
};
struct odirect {
u_long d_ino;
u_short d_reclen;
u_short d_namlen;
u_char d_name[MAXNAMLEN + 1];
} oroot_dir[] = {
{ ROOTINO, sizeof(struct direct), 1, "." },
{ ROOTINO, sizeof(struct direct), 2, ".." },
#ifdef LOSTDIR
{ LOSTFOUNDINO, sizeof(struct direct), 10, "lost+found" },
#endif
};
#ifdef LOSTDIR
struct direct lost_found_dir[] = {
{ LOSTFOUNDINO, sizeof(struct direct), DT_DIR, 1, "." },
{ ROOTINO, sizeof(struct direct), DT_DIR, 2, ".." },
{ 0, DIRBLKSIZ, 0, 0, 0 },
};
struct odirect olost_found_dir[] = {
{ LOSTFOUNDINO, sizeof(struct direct), 1, "." },
{ ROOTINO, sizeof(struct direct), 2, ".." },
{ 0, DIRBLKSIZ, 0, 0 },
};
#endif
char buf[MAXBSIZE];
void
fsinit(utime)
time_t utime;
{
#ifdef LOSTDIR
int i;
#endif
/*
* initialize the node
*/
node.di_atime = utime;
node.di_mtime = utime;
node.di_ctime = utime;
#ifdef LOSTDIR
/*
* create the lost+found directory
*/
if (Oflag) {
(void)makedir((struct direct *)olost_found_dir, 2);
for (i = DIRBLKSIZ; i < sblock.fs_bsize; i += DIRBLKSIZ)
memmove(&buf[i], &olost_found_dir[2],
DIRSIZ(0, &olost_found_dir[2]));
} else {
(void)makedir(lost_found_dir, 2);
for (i = DIRBLKSIZ; i < sblock.fs_bsize; i += DIRBLKSIZ)
memmove(&buf[i], &lost_found_dir[2],
DIRSIZ(0, &lost_found_dir[2]));
}
node.di_mode = IFDIR | UMASK;
node.di_nlink = 2;
node.di_size = sblock.fs_bsize;
node.di_db[0] = alloc(node.di_size, node.di_mode);
node.di_blocks = btodb(fragroundup(&sblock, node.di_size));
wtfs(fsbtodb(&sblock, node.di_db[0]), node.di_size, buf);
iput(&node, LOSTFOUNDINO);
#endif
/*
* create the root directory
*/
node.di_mode = IFDIR | UMASK;
node.di_nlink = PREDEFDIR;
if (Oflag)
node.di_size = makedir((struct direct *)oroot_dir, PREDEFDIR);
else
node.di_size = makedir(root_dir, PREDEFDIR);
node.di_db[0] = alloc(sblock.fs_fsize, node.di_mode);
node.di_blocks = btodb(fragroundup(&sblock, node.di_size));
wtfs(fsbtodb(&sblock, node.di_db[0]), sblock.fs_fsize, buf);
iput(&node, ROOTINO);
}
/*
* construct a set of directory entries in "buf".
* return size of directory.
*/
int
makedir(protodir, entries)
register struct direct *protodir;
int entries;
{
char *cp;
int i, spcleft;
spcleft = DIRBLKSIZ;
for (cp = buf, i = 0; i < entries - 1; i++) {
protodir[i].d_reclen = DIRSIZ(0, &protodir[i]);
memmove(cp, &protodir[i], protodir[i].d_reclen);
cp += protodir[i].d_reclen;
spcleft -= protodir[i].d_reclen;
}
protodir[i].d_reclen = spcleft;
memmove(cp, &protodir[i], DIRSIZ(0, &protodir[i]));
return (DIRBLKSIZ);
}
/*
* allocate a block or frag
*/
daddr_t
alloc(size, mode)
int size;
int mode;
{
int i, frag;
daddr_t d, blkno;
rdfs(fsbtodb(&sblock, cgtod(&sblock, 0)), sblock.fs_cgsize,
(char *)&acg);
if (acg.cg_magic != CG_MAGIC) {
printf("cg 0: bad magic number\n");
return (0);
}
if (acg.cg_cs.cs_nbfree == 0) {
printf("first cylinder group ran out of space\n");
return (0);
}
for (d = 0; d < acg.cg_ndblk; d += sblock.fs_frag)
if (isblock(&sblock, cg_blksfree(&acg), d / sblock.fs_frag))
goto goth;
printf("internal error: can't find block in cyl 0\n");
return (0);
goth:
blkno = fragstoblks(&sblock, d);
clrblock(&sblock, cg_blksfree(&acg), blkno);
if (sblock.fs_contigsumsize > 0)
clrbit(cg_clustersfree(&acg), blkno);
acg.cg_cs.cs_nbfree--;
sblock.fs_cstotal.cs_nbfree--;
fscs[0].cs_nbfree--;
if (mode & IFDIR) {
acg.cg_cs.cs_ndir++;
sblock.fs_cstotal.cs_ndir++;
fscs[0].cs_ndir++;
}
cg_blktot(&acg)[cbtocylno(&sblock, d)]--;
cg_blks(&sblock, &acg, cbtocylno(&sblock, d))[cbtorpos(&sblock, d)]--;
if (size != sblock.fs_bsize) {
frag = howmany(size, sblock.fs_fsize);
fscs[0].cs_nffree += sblock.fs_frag - frag;
sblock.fs_cstotal.cs_nffree += sblock.fs_frag - frag;
acg.cg_cs.cs_nffree += sblock.fs_frag - frag;
acg.cg_frsum[sblock.fs_frag - frag]++;
for (i = frag; i < sblock.fs_frag; i++)
setbit(cg_blksfree(&acg), d + i);
}
wtfs(fsbtodb(&sblock, cgtod(&sblock, 0)), sblock.fs_cgsize,
(char *)&acg);
return (d);
}
/*
* Calculate number of inodes per group.
*/
long
calcipg(cpg, bpcg, usedbp)
long cpg;
long bpcg;
off_t *usedbp;
{
int i;
long ipg, new_ipg, ncg, ncyl;
off_t usedb;
/*
* Prepare to scale by fssize / (number of sectors in cylinder groups).
* Note that fssize is still in sectors, not filesystem blocks.
*/
ncyl = howmany(fssize, (u_int)secpercyl);
ncg = howmany(ncyl, cpg);
/*
* Iterate a few times to allow for ipg depending on itself.
*/
ipg = 0;
for (i = 0; i < 10; i++) {
usedb = (sblock.fs_iblkno + ipg / INOPF(&sblock))
* NSPF(&sblock) * (off_t)sectorsize;
new_ipg = (cpg * (quad_t)bpcg - usedb) / density * fssize
/ ncg / secpercyl / cpg;
new_ipg = roundup(new_ipg, INOPB(&sblock));
if (new_ipg == ipg)
break;
ipg = new_ipg;
}
*usedbp = usedb;
return (ipg);
}
/*
* Allocate an inode on the disk
*/
void
iput(ip, ino)
register struct dinode *ip;
register ino_t ino;
{
struct dinode buf[MAXINOPB];
daddr_t d;
int c;
#ifdef FSIRAND
ip->di_gen = random();
#endif
c = ino_to_cg(&sblock, ino);
rdfs(fsbtodb(&sblock, cgtod(&sblock, 0)), sblock.fs_cgsize,
(char *)&acg);
if (acg.cg_magic != CG_MAGIC) {
printf("cg 0: bad magic number\n");
exit(31);
}
acg.cg_cs.cs_nifree--;
setbit(cg_inosused(&acg), ino);
wtfs(fsbtodb(&sblock, cgtod(&sblock, 0)), sblock.fs_cgsize,
(char *)&acg);
sblock.fs_cstotal.cs_nifree--;
fscs[0].cs_nifree--;
if (ino >= sblock.fs_ipg * sblock.fs_ncg) {
printf("fsinit: inode value out of range (%d).\n", ino);
exit(32);
}
d = fsbtodb(&sblock, ino_to_fsba(&sblock, ino));
rdfs(d, sblock.fs_bsize, (char *)buf);
buf[ino_to_fsbo(&sblock, ino)] = *ip;
wtfs(d, sblock.fs_bsize, (char *)buf);
}
#ifdef STANDALONE
/*
* Replace libc function with one suited to our needs.
*/
caddr_t
malloc(size)
register u_long size;
{
char *base, *i;
static u_long pgsz;
struct rlimit rlp;
if (pgsz == 0) {
base = sbrk(0);
pgsz = getpagesize() - 1;
i = (char *)((u_long)(base + pgsz) &~ pgsz);
base = sbrk(i - base);
if (getrlimit(RLIMIT_DATA, &rlp) < 0)
warn("getrlimit");
rlp.rlim_cur = rlp.rlim_max;
if (setrlimit(RLIMIT_DATA, &rlp) < 0)
warn("setrlimit");
memleft = rlp.rlim_max - (u_long)base;
}
size = (size + pgsz) &~ pgsz;
if (size > memleft)
size = memleft;
memleft -= size;
if (size == 0)
return (0);
return ((caddr_t)sbrk(size));
}
/*
* Replace libc function with one suited to our needs.
*/
caddr_t
realloc(ptr, size)
char *ptr;
u_long size;
{
void *p;
if ((p = malloc(size)) == NULL)
return (NULL);
memmove(p, ptr, size);
free(ptr);
return (p);
}
/*
* Replace libc function with one suited to our needs.
*/
char *
calloc(size, numelm)
u_long size, numelm;
{
caddr_t base;
size *= numelm;
if ((base = malloc(size)) == NULL)
return (NULL);
memset(base, 0, size);
return (base);
}
/*
* Replace libc function with one suited to our needs.
*/
void
free(ptr)
char *ptr;
{
/* do not worry about it for now */
}
#else /* !STANDALONE */
#ifdef __ELF__
extern char *_etext;
#define etext _etext
#else
extern char *etext;
#endif
#endif /* STANDALONE */
/*
* read a block from the file system
*/
void
rdfs(bno, size, bf)
daddr_t bno;
int size;
char *bf;
{
int n;
wtfsflush();
if (lseek(fsi, (off_t)bno * sectorsize, 0) < 0) {
printf("seek error: %ld\n", (long)bno);
err(33, "rdfs");
}
n = read(fsi, bf, size);
if (n != size) {
printf("read error: %ld\n", (long)bno);
err(34, "rdfs");
}
}
#define WCSIZE (128 * 1024)
daddr_t wc_sect; /* units of sectorsize */
int wc_end; /* bytes */
static char wc[WCSIZE]; /* bytes */
/*
* Flush dirty write behind buffer.
*/
void
wtfsflush()
{
int n;
if (wc_end) {
if (lseek(fso, (off_t)wc_sect * sectorsize, SEEK_SET) < 0) {
printf("seek error: %ld\n", (long)wc_sect);
err(35, "wtfs - writecombine");
}
n = write(fso, wc, wc_end);
if (n != wc_end) {
printf("write error: %ld\n", (long)wc_sect);
err(36, "wtfs - writecombine");
}
wc_end = 0;
}
}
/*
* write a block to the file system
*/
void
wtfs(bno, size, bf)
daddr_t bno;
int size;
char *bf;
{
int n;
int done;
if (Nflag)
return;
done = 0;
if (wc_end == 0 && size <= WCSIZE) {
wc_sect = bno;
bcopy(bf, wc, size);
wc_end = size;
if (wc_end < WCSIZE)
return;
done = 1;
}
if ((off_t)wc_sect * sectorsize + wc_end == (off_t)bno * sectorsize &&
wc_end + size <= WCSIZE) {
bcopy(bf, wc + wc_end, size);
wc_end += size;
if (wc_end < WCSIZE)
return;
done = 1;
}
wtfsflush();
if (done)
return;
if (lseek(fso, (off_t)bno * sectorsize, SEEK_SET) < 0) {
printf("seek error: %ld\n", (long)bno);
err(35, "wtfs");
}
n = write(fso, bf, size);
if (n != size) {
printf("write error: %ld\n", (long)bno);
err(36, "wtfs");
}
}
/*
* check if a block is available
*/
int
isblock(fs, cp, h)
struct fs *fs;
unsigned char *cp;
int h;
{
unsigned char mask;
switch (fs->fs_frag) {
case 8:
return (cp[h] == 0xff);
case 4:
mask = 0x0f << ((h & 0x1) << 2);
return ((cp[h >> 1] & mask) == mask);
case 2:
mask = 0x03 << ((h & 0x3) << 1);
return ((cp[h >> 2] & mask) == mask);
case 1:
mask = 0x01 << (h & 0x7);
return ((cp[h >> 3] & mask) == mask);
default:
#ifdef STANDALONE
printf("isblock bad fs_frag %d\n", fs->fs_frag);
#else
fprintf(stderr, "isblock bad fs_frag %d\n", fs->fs_frag);
#endif
return (0);
}
}
/*
* take a block out of the map
*/
void
clrblock(fs, cp, h)
struct fs *fs;
unsigned char *cp;
int h;
{
switch ((fs)->fs_frag) {
case 8:
cp[h] = 0;
return;
case 4:
cp[h >> 1] &= ~(0x0f << ((h & 0x1) << 2));
return;
case 2:
cp[h >> 2] &= ~(0x03 << ((h & 0x3) << 1));
return;
case 1:
cp[h >> 3] &= ~(0x01 << (h & 0x7));
return;
default:
#ifdef STANDALONE
printf("clrblock bad fs_frag %d\n", fs->fs_frag);
#else
fprintf(stderr, "clrblock bad fs_frag %d\n", fs->fs_frag);
#endif
return;
}
}
/*
* put a block into the map
*/
void
setblock(fs, cp, h)
struct fs *fs;
unsigned char *cp;
int h;
{
switch (fs->fs_frag) {
case 8:
cp[h] = 0xff;
return;
case 4:
cp[h >> 1] |= (0x0f << ((h & 0x1) << 2));
return;
case 2:
cp[h >> 2] |= (0x03 << ((h & 0x3) << 1));
return;
case 1:
cp[h >> 3] |= (0x01 << (h & 0x7));
return;
default:
#ifdef STANDALONE
printf("setblock bad fs_frag %d\n", fs->fs_frag);
#else
fprintf(stderr, "setblock bad fs_frag %d\n", fs->fs_frag);
#endif
return;
}
}
/*
* Determine the number of characters in a
* single line.
*/
static int
charsperline()
{
int columns;
char *cp;
struct winsize ws;
columns = 0;
if (ioctl(0, TIOCGWINSZ, &ws) != -1)
columns = ws.ws_col;
if (columns == 0 && (cp = getenv("COLUMNS")))
columns = atoi(cp);
if (columns == 0)
columns = 80; /* last resort */
return columns;
}