Import sources from 2011-03-30 iso image

1 files changed, 799 insertions, 0 deletions

diff --git a/sys/src/cmd/disk/format.c b/sys/src/cmd/disk/format.c
new file mode 100755
index 000000000..2ada3abfa
--- /dev/null
+++ b/sys/src/cmd/disk/format.c
@@ -0,0 +1,799 @@
+#include <u.h>
+#include <libc.h>
+#include <ctype.h>
+#include <disk.h>
+
+/*
+ *  disk types (all MFM encoding)
+ */
+typedef struct Type	Type;
+struct Type
+{
+	char	*name;
+	int	bytes;		/* bytes/sector */
+	int	sectors;	/* sectors/track */
+	int	heads;		/* number of heads */
+	int	tracks;		/* tracks/disk */
+	int	media;		/* media descriptor byte */
+	int	cluster;	/* default cluster size */
+};
+Type floppytype[] =
+{
+ { "3½HD",	512, 18,  2, 80, 0xf0, 1, },
+ { "3½DD",	512,  9,  2, 80, 0xf9, 2, },
+ { "3½QD",	512, 36, 2, 80, 0xf9, 2, },	/* invented */
+ { "5¼HD",	512, 15,  2, 80, 0xf9, 1, },
+ { "5¼DD",	512,  9,  2, 40, 0xfd, 2, },
+ { "hard",	512,  0,  0, 0, 0xf8, 4, },
+};
+
+#define NTYPES (sizeof(floppytype)/sizeof(Type))
+
+typedef struct Dosboot	Dosboot;
+struct Dosboot{
+	uchar	magic[3];	/* really an x86 JMP instruction */
+	uchar	version[8];
+	uchar	sectsize[2];
+	uchar	clustsize;
+	uchar	nresrv[2];
+	uchar	nfats;
+	uchar	rootsize[2];
+	uchar	volsize[2];
+	uchar	mediadesc;
+	uchar	fatsize[2];
+	uchar	trksize[2];
+	uchar	nheads[2];
+	uchar	nhidden[4];
+	uchar	bigvolsize[4];
+	uchar	driveno;
+	uchar	reserved0;
+	uchar	bootsig;
+	uchar	volid[4];
+	uchar	label[11];
+	uchar	type[8];
+};
+#define	PUTSHORT(p, v) { (p)[1] = (v)>>8; (p)[0] = (v); }
+#define	PUTLONG(p, v) { PUTSHORT((p), (v)); PUTSHORT((p)+2, (v)>>16); }
+#define	GETSHORT(p)	(((p)[1]<<8)|(p)[0])
+#define	GETLONG(p)	(((ulong)GETSHORT(p+2)<<16)|(ulong)GETSHORT(p))
+
+typedef struct Dosdir	Dosdir;
+struct Dosdir
+{
+	uchar	name[8];
+	uchar	ext[3];
+	uchar	attr;
+	uchar	reserved[10];
+	uchar	time[2];
+	uchar	date[2];
+	uchar	start[2];
+	uchar	length[4];
+};
+
+#define	DRONLY	0x01
+#define	DHIDDEN	0x02
+#define	DSYSTEM	0x04
+#define	DVLABEL	0x08
+#define	DDIR	0x10
+#define	DARCH	0x20
+
+/*
+ *  the boot program for the boot sector.
+ */
+int nbootprog = 188;	/* no. of bytes of boot program, including the first 0x3E */
+uchar bootprog[512] =
+{
+[0x000]	0xEB, 0x3C, 0x90, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+[0x03E] 0xFA, 0xFC, 0x8C, 0xC8, 0x8E, 0xD8, 0x8E, 0xD0,
+	0xBC, 0x00, 0x7C, 0xBE, 0x77, 0x7C, 0xE8, 0x19,
+	0x00, 0x33, 0xC0, 0xCD, 0x16, 0xBB, 0x40, 0x00,
+	0x8E, 0xC3, 0xBB, 0x72, 0x00, 0xB8, 0x34, 0x12,
+	0x26, 0x89, 0x07, 0xEA, 0x00, 0x00, 0xFF, 0xFF,
+	0xEB, 0xD6, 0xAC, 0x0A, 0xC0, 0x74, 0x09, 0xB4,
+	0x0E, 0xBB, 0x07, 0x00, 0xCD, 0x10, 0xEB, 0xF2,
+	0xC3,  'N',  'o',  't',  ' ',  'a',  ' ',  'b',
+	 'o',  'o',  't',  'a',  'b',  'l',  'e',  ' ',
+	 'd',  'i',  's',  'c',  ' ',  'o',  'r',  ' ',
+	 'd',  'i',  's',  'c',  ' ',  'e',  'r',  'r',
+	 'o',  'r', '\r', '\n',  'P',  'r',  'e',  's',
+	 's',  ' ',  'a',  'l',  'm',  'o',  's',  't',
+	 ' ',  'a',  'n',  'y',  ' ',  'k',  'e',  'y',
+	 ' ',  't',  'o',  ' ',  'r',  'e',  'b',  'o',
+	 'o',  't',  '.',  '.',  '.', 0x00, 0x00, 0x00,
+[0x1F0]	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x55, 0xAA,
+};
+
+char *dev;
+int clustersize;
+uchar *fat;	/* the fat */
+int fatbits;
+int fatsecs;
+int fatlast;	/* last cluster allocated */
+int clusters;
+int fatsecs;
+vlong volsecs;
+uchar *root;	/* first block of root */
+int rootsecs;
+int rootfiles;
+int rootnext;
+int nresrv = 1;
+int chatty;
+vlong length;
+Type *t;
+int fflag;
+int hflag;
+int xflag;
+char *file;
+char *pbs;
+char *type;
+char *bootfile;
+int dos;
+
+enum
+{
+	Sof = 1,	/* start of file */
+	Eof = 2,	/* end of file */
+};
+
+void	dosfs(int, int, Disk*, char*, int, char*[], int);
+ulong	clustalloc(int);
+void	addrname(uchar*, Dir*, char*, ulong);
+void	sanitycheck(Disk*);
+
+void
+usage(void)
+{
+	fprint(2, "usage: disk/format [-df] [-b bootblock] [-c csize] "
+		"[-l label] [-r nresrv] [-t type] disk [files ...]\n");
+	exits("usage");
+}
+
+void
+fatal(char *fmt, ...)
+{
+	char err[128];
+	va_list arg;
+
+	va_start(arg, fmt);
+	vsnprint(err, sizeof(err), fmt, arg);
+	va_end(arg);
+	fprint(2, "format: %s\n", err);
+	if(fflag && file)
+		remove(file);
+	exits(err);
+}
+
+void
+main(int argc, char **argv)
+{
+	int fd, n, writepbs;
+	char buf[512], label[11];
+	char *a;
+	Disk *disk;
+
+	dos = 0;
+	type = nil;
+	clustersize = 0;
+	writepbs = 0;
+	memmove(label, "CYLINDRICAL", sizeof(label));
+	ARGBEGIN {
+	case 'b':
+		pbs = EARGF(usage());
+		writepbs = 1;
+		break;
+	case 'c':
+		clustersize = atoi(EARGF(usage()));
+		break;
+	case 'd':
+		dos = 1;
+		writepbs = 1;
+		break;
+	case 'f':
+		fflag = 1;
+		break;
+	case 'l':
+		a = EARGF(usage());
+		n = strlen(a);
+		if(n > sizeof(label))
+			n = sizeof(label);
+		memmove(label, a, n);
+		while(n < sizeof(label))
+			label[n++] = ' ';
+		break;
+	case 'r':
+		nresrv = atoi(EARGF(usage()));
+		break;
+	case 't':
+		type = EARGF(usage());
+		break;
+	case 'v':
+		chatty++;
+		break;
+	case 'x':
+		xflag = 1;
+		break;
+	default:
+		usage();
+	} ARGEND
+
+	if(argc < 1)
+		usage();
+
+	disk = opendisk(argv[0], 0, 0);
+	if(disk == nil) {
+		if(fflag) {
+			if((fd = create(argv[0], ORDWR, 0666)) >= 0) {
+				file = argv[0];
+				close(fd);
+				disk = opendisk(argv[0], 0, 0);
+			}
+		}
+	}
+	if(disk == nil)
+		fatal("opendisk: %r");
+
+	if(disk->type == Tfile)
+		fflag = 1;
+
+	if(type == nil) {
+		switch(disk->type){
+		case Tfile:
+			type = "3½HD";
+			break;
+		case Tfloppy:
+			seek(disk->ctlfd, 0, 0);
+			n = read(disk->ctlfd, buf, 10);
+			if(n <= 0 || n >= 10)
+				fatal("reading floppy type");
+			buf[n] = 0;
+			type = strdup(buf);
+			if(type == nil)
+				fatal("out of memory");
+			break;
+		case Tsd:
+			type = "hard";
+			break;
+		default:
+			type = "unknown";
+			break;
+		}
+	}
+
+	if(!fflag && disk->type == Tfloppy)
+		if(fprint(disk->ctlfd, "format %s", type) < 0)
+			fatal("formatting floppy as %s: %r", type);
+
+	if(disk->type != Tfloppy)
+		sanitycheck(disk);
+
+	/* check that everything will succeed */
+	dosfs(dos, writepbs, disk, label, argc-1, argv+1, 0);
+
+	/* commit */
+	dosfs(dos, writepbs, disk, label, argc-1, argv+1, 1);
+
+	print("used %lld bytes\n", fatlast*clustersize*disk->secsize);
+	exits(0);
+}
+
+/*
+ * Look for a partition table on sector 1, as would be the
+ * case if we were erroneously formatting 9fat without -r 2.
+ * If it's there and nresrv is not big enough, complain and exit.
+ * I've blown away my partition table too many times.
+ */
+void
+sanitycheck(Disk *disk)
+{
+	char buf[512];
+	int bad;
+
+	if(xflag)
+		return;
+
+	bad = 0;
+	if(dos && nresrv < 2 && seek(disk->fd, disk->secsize, 0) == disk->secsize
+	&& read(disk->fd, buf, sizeof(buf)) >= 5 && strncmp(buf, "part ", 5) == 0) {
+		fprint(2, 
+			"there's a plan9 partition on the disk\n"
+			"and you didn't specify -r 2 (or greater).\n"
+			"either specify -r 2 or -x to disable this check.\n");
+		bad = 1;
+	}
+
+	if(disk->type == Tsd && disk->offset == 0LL) {
+		fprint(2,
+			"you're attempting to format your disk (/dev/sdXX/data)\n"
+			"rather than a partition like /dev/sdXX/9fat;\n"
+			"this is likely a mistake.  specify -x to disable this check.\n");
+		bad = 1;
+	}
+
+	if(bad)
+		exits("failed disk sanity check");
+}
+
+/*
+ * Return the BIOS drive number for the disk.
+ * 0x80 is the first fixed disk, 0x81 the next, etc.
+ * We map sdC0=0x80, sdC1=0x81, sdD0=0x82, sdD1=0x83
+ */
+int
+getdriveno(Disk *disk)
+{
+	char buf[64], *p;
+
+	if(disk->type != Tsd)
+		return 0x80;	/* first hard disk */
+
+	if(fd2path(disk->fd, buf, sizeof(buf)) < 0)
+		return 0x80;
+
+	/*
+	 * The name is of the format #SsdC0/foo 
+	 * or /dev/sdC0/foo.
+	 * So that we can just look for /sdC0, turn 
+	 * #SsdC0/foo into #/sdC0/foo.
+	 */
+	if(buf[0] == '#' && buf[1] == 'S')
+		buf[1] = '/';
+
+	for(p=buf; *p; p++)
+		if(p[0] == 's' && p[1] == 'd' && (p[2]=='C' || p[2]=='D') &&
+		    (p[3]=='0' || p[3]=='1'))
+			return 0x80 + (p[2]-'C')*2 + (p[3]-'0');
+		
+	return 0x80;
+}
+
+long
+writen(int fd, void *buf, long n)
+{
+	long m, tot;
+
+	/* write 8k at a time, to be nice to the disk subsystem */
+	for(tot=0; tot<n; tot+=m){
+		m = n - tot;
+		if(m > 8192)
+			m = 8192;
+		if(write(fd, (uchar*)buf+tot, m) != m)
+			break;
+	}
+	return tot;
+}
+
+void
+dosfs(int dofat, int dopbs, Disk *disk, char *label, int argc, char *argv[], int commit)
+{
+	char r[16];
+	Dosboot *b;
+	uchar *buf, *pbsbuf, *p;
+	Dir *d;
+	int i, data, newclusters, npbs, n, sysfd;
+	ulong x;
+	vlong length, secsize;
+
+	if(dofat == 0 && dopbs == 0)
+		return;
+
+	for(t = floppytype; t < &floppytype[NTYPES]; t++)
+		if(strcmp(type, t->name) == 0)
+			break;
+	if(t == &floppytype[NTYPES])
+		fatal("unknown floppy type %s", type);
+
+	if(t->sectors == 0 && strcmp(type, "hard") == 0) {
+		t->sectors = disk->s;
+		t->heads = disk->h;
+		t->tracks = disk->c;
+	}
+
+	if(t->sectors == 0 && dofat)
+		fatal("cannot format fat with type %s: geometry unknown\n", type);
+
+	if(fflag){
+		disk->size = t->bytes*t->sectors*t->heads*t->tracks;
+		disk->secsize = t->bytes;
+		disk->secs = disk->size / disk->secsize;
+	}
+
+	secsize = disk->secsize;
+	length = disk->size;
+
+	buf = malloc(secsize);
+	if(buf == 0)
+		fatal("out of memory");
+
+	/*
+	 * Make disk full size if a file.
+	 */
+	if(fflag && disk->type == Tfile){
+		if((d = dirfstat(disk->wfd)) == nil)
+			fatal("fstat disk: %r");
+		if(commit && d->length < disk->size) {
+			if(seek(disk->wfd, disk->size-1, 0) < 0)
+				fatal("seek to 9: %r");
+			if(write(disk->wfd, "9", 1) < 0)
+				fatal("writing 9: @%lld %r", seek(disk->wfd, 0LL, 1));
+		}
+		free(d);
+	}
+
+	/*
+	 * Start with initial sector from disk
+	 */
+	if(seek(disk->fd, 0, 0) < 0)
+		fatal("seek to boot sector: %r\n");
+	if(commit && read(disk->fd, buf, secsize) != secsize)
+		fatal("reading boot sector: %r");
+
+	if(dofat)
+		memset(buf, 0, sizeof(Dosboot));
+
+	/*
+	 * Jump instruction and OEM name.
+	 */
+	b = (Dosboot*)buf;
+	b->magic[0] = 0xEB;
+	b->magic[1] = 0x3C;
+	b->magic[2] = 0x90;
+	memmove(b->version, "Plan9.00", sizeof(b->version));
+	
+	/*
+	 * Add bootstrapping code; assume it starts 
+	 * at 0x3E (the destination of the jump we just
+	 * wrote to b->magic).
+	 */
+	if(dopbs) {
+		pbsbuf = malloc(secsize);
+		if(pbsbuf == 0)
+			fatal("out of memory");
+
+		if(pbs){
+			if((sysfd = open(pbs, OREAD)) < 0)
+				fatal("open %s: %r", pbs);
+			if((npbs = read(sysfd, pbsbuf, secsize)) < 0)
+				fatal("read %s: %r", pbs);
+
+			if(npbs > secsize-2)
+				fatal("boot block too large");
+
+			close(sysfd);
+		}
+		else {
+			memmove(pbsbuf, bootprog, sizeof(bootprog));
+			npbs = nbootprog;
+		}
+		if(npbs <= 0x3E)
+			fprint(2, "warning: pbs too small\n");
+		else
+			memmove(buf+0x3E, pbsbuf+0x3E, npbs-0x3E);
+
+		free(pbsbuf);
+	}
+
+	/*
+	 * Add FAT BIOS parameter block.
+	 */
+	if(dofat) {
+		if(commit) {
+			print("Initializing FAT file system\n");
+			print("type %s, %d tracks, %d heads, %d sectors/track, %lld bytes/sec\n",
+				t->name, t->tracks, t->heads, t->sectors, secsize);
+		}
+
+		if(clustersize == 0)
+			clustersize = t->cluster;
+		/*
+		 * the number of fat bits depends on how much disk is left
+		 * over after you subtract out the space taken up by the fat tables. 
+		 * try both.  what a crock.
+		 */
+		fatbits = 12;
+Tryagain:
+		volsecs = length/secsize;
+		/*
+		 * here's a crock inside a crock.  even having fixed fatbits,
+		 * the number of fat sectors depends on the number of clusters,
+		 * but of course we don't know yet.  maybe iterating will get us there.
+		 * or maybe it will cycle.
+		 */
+		clusters = 0;
+		for(i=0;; i++){
+			fatsecs = (fatbits*clusters + 8*secsize - 1)/(8*secsize);
+			rootsecs = volsecs/200;
+			rootfiles = rootsecs * (secsize/sizeof(Dosdir));
+			if(rootfiles > 512){
+				rootfiles = 512;
+				rootsecs = rootfiles/(secsize/sizeof(Dosdir));
+			}
+			data = nresrv + 2*fatsecs + (rootfiles*sizeof(Dosdir) + secsize-1)/secsize;
+			newclusters = 2 + (volsecs - data)/clustersize;
+			if(newclusters == clusters)
+				break;
+			clusters = newclusters;
+			if(i > 10)
+				fatal("can't decide how many clusters to use (%d? %d?)", clusters, newclusters);
+if(chatty) print("clusters %d\n", clusters);
+		}
+				
+if(chatty) print("try %d fatbits => %d clusters of %d\n", fatbits, clusters, clustersize);
+		switch(fatbits){
+		case 12:
+			if(clusters >= 4087){
+				fatbits = 16;
+				goto Tryagain;
+			}
+			break;
+		case 16:
+			if(clusters >= 65527)
+				fatal("disk too big; implement fat32");
+			break;
+		}
+		PUTSHORT(b->sectsize, secsize);
+		b->clustsize = clustersize;
+		PUTSHORT(b->nresrv, nresrv);
+		b->nfats = 2;
+		PUTSHORT(b->rootsize, rootfiles);
+		if(volsecs < (1<<16))
+			PUTSHORT(b->volsize, volsecs);
+		b->mediadesc = t->media;
+		PUTSHORT(b->fatsize, fatsecs);
+		PUTSHORT(b->trksize, t->sectors);
+		PUTSHORT(b->nheads, t->heads);
+		PUTLONG(b->nhidden, disk->offset);
+		PUTLONG(b->bigvolsize, volsecs);
+	
+		/*
+		 * Extended BIOS Parameter Block.
+		 */
+		if(t->media == 0xF8)
+			b->driveno = getdriveno(disk);
+		else
+			b->driveno = 0;
+if(chatty) print("driveno = %ux\n", b->driveno);
+	
+		b->bootsig = 0x29;
+		x = disk->offset + b->nfats*fatsecs + nresrv;
+		PUTLONG(b->volid, x);
+if(chatty) print("volid = %lux %lux\n", x, GETLONG(b->volid));
+		memmove(b->label, label, sizeof(b->label));
+		sprint(r, "FAT%d    ", fatbits);
+		memmove(b->type, r, sizeof(b->type));
+	}
+
+	buf[secsize-2] = 0x55;
+	buf[secsize-1] = 0xAA;
+
+	if(commit) {
+		if(seek(disk->wfd, 0, 0) < 0)
+			fatal("seek to boot sector: %r\n");
+		if(write(disk->wfd, buf, secsize) != secsize)
+			fatal("writing boot sector: %r");
+	}
+
+	free(buf);
+
+	/*
+	 * If we were only called to write the PBS, leave now.
+	 */
+	if(dofat == 0)
+		return;
+
+	/*
+	 *  allocate an in memory fat
+	 */
+	if(seek(disk->wfd, nresrv*secsize, 0) < 0)
+		fatal("seek to fat: %r\n");
+if(chatty) print("fat @%lluX\n", seek(disk->wfd, 0, 1));
+	fat = malloc(fatsecs*secsize);
+	if(fat == 0)
+		fatal("out of memory");
+	memset(fat, 0, fatsecs*secsize);
+	fat[0] = t->media;
+	fat[1] = 0xff;
+	fat[2] = 0xff;
+	if(fatbits == 16)
+		fat[3] = 0xff;
+	fatlast = 1;
+	if(seek(disk->wfd, 2*fatsecs*secsize, 1) < 0)	/* 2 fats */
+		fatal("seek to root: %r");
+if(chatty) print("root @%lluX\n", seek(disk->wfd, 0LL, 1));
+
+	/*
+	 *  allocate an in memory root
+	 */
+	root = malloc(rootsecs*secsize);
+	if(root == 0)
+		fatal("out of memory");
+	memset(root, 0, rootsecs*secsize);
+	if(seek(disk->wfd, rootsecs*secsize, 1) < 0)	/* rootsecs */
+		fatal("seek to files: %r");
+if(chatty) print("files @%lluX\n", seek(disk->wfd, 0LL, 1));
+
+	/*
+	 * Now positioned at the Files Area.
+	 * If we have any arguments, process 
+	 * them and write out.
+	 */
+	for(p = root; argc > 0; argc--, argv++, p += sizeof(Dosdir)){
+		if(p >= (root+(rootsecs*secsize)))
+			fatal("too many files in root");
+		/*
+		 * Open the file and get its length.
+		 */
+		if((sysfd = open(*argv, OREAD)) < 0)
+			fatal("open %s: %r", *argv);
+		if((d = dirfstat(sysfd)) == nil)
+			fatal("stat %s: %r", *argv);
+		if(d->length > 0xFFFFFFFFU)
+			fatal("file %s too big\n", *argv, d->length);
+		if(commit)
+			print("Adding file %s, length %lld\n", *argv, d->length);
+
+		length = d->length;
+		if(length){
+			/*
+			 * Allocate a buffer to read the entire file into.
+			 * This must be rounded up to a cluster boundary.
+			 *
+			 * Read the file and write it out to the Files Area.
+			 */
+			length += secsize*clustersize - 1;
+			length /= secsize*clustersize;
+			length *= secsize*clustersize;
+			if((buf = malloc(length)) == 0)
+				fatal("out of memory");
+	
+			if(readn(sysfd, buf, d->length) != d->length)
+				fatal("read %s: %r", *argv);
+			memset(buf+d->length, 0, length-d->length);
+if(chatty) print("%s @%lluX\n", d->name, seek(disk->wfd, 0LL, 1));
+			if(commit && writen(disk->wfd, buf, length) != length)
+				fatal("write %s: %r", *argv);
+			free(buf);
+
+			close(sysfd);
+	
+			/*
+			 * Allocate the FAT clusters.
+			 * We're assuming here that where we
+			 * wrote the file is in sync with
+			 * the cluster allocation.
+			 * Save the starting cluster.
+			 */
+			length /= secsize*clustersize;
+			x = clustalloc(Sof);
+			for(n = 0; n < length-1; n++)
+				clustalloc(0);
+			clustalloc(Eof);
+		}
+		else
+			x = 0;
+
+		/*
+		 * Add the filename to the root.
+		 */
+fprint(2, "add %s at clust %lux\n", d->name, x);
+		addrname(p, d, *argv, x);
+		free(d);
+	}
+
+	/*
+	 *  write the fats and root
+	 */
+	if(commit) {
+		if(seek(disk->wfd, nresrv*secsize, 0) < 0)
+			fatal("seek to fat #1: %r");
+		if(write(disk->wfd, fat, fatsecs*secsize) < 0)
+			fatal("writing fat #1: %r");
+		if(write(disk->wfd, fat, fatsecs*secsize) < 0)
+			fatal("writing fat #2: %r");
+		if(write(disk->wfd, root, rootsecs*secsize) < 0)
+			fatal("writing root: %r");
+	}
+
+	free(fat);
+	free(root);
+}
+
+/*
+ *  allocate a cluster
+ */
+ulong
+clustalloc(int flag)
+{
+	ulong o, x;
+
+	if(flag != Sof){
+		x = (flag == Eof) ? 0xffff : (fatlast+1);
+		if(fatbits == 12){
+			x &= 0xfff;
+			o = (3*fatlast)/2;
+			if(fatlast & 1){
+				fat[o] = (fat[o]&0x0f) | (x<<4);
+				fat[o+1] = (x>>4);
+			} else {
+				fat[o] = x;
+				fat[o+1] = (fat[o+1]&0xf0) | ((x>>8) & 0x0F);
+			}
+		} else {
+			o = 2*fatlast;
+			fat[o] = x;
+			fat[o+1] = x>>8;
+		}
+	}
+		
+	if(flag == Eof)
+		return 0;
+	else{
+		++fatlast;
+		if(fatlast >= clusters)
+			sysfatal("data does not fit on disk (%d %d)", fatlast, clusters);
+		return fatlast;
+	}
+}
+
+void
+putname(char *p, Dosdir *d)
+{
+	int i;
+
+	memset(d->name, ' ', sizeof d->name+sizeof d->ext);
+	for(i = 0; i< sizeof(d->name); i++){
+		if(*p == 0 || *p == '.')
+			break;
+		d->name[i] = toupper(*p++);
+	}
+	p = strrchr(p, '.');
+	if(p){
+		for(i = 0; i < sizeof d->ext; i++){
+			if(*++p == 0)
+				break;
+			d->ext[i] = toupper(*p);
+		}
+	}
+}
+
+void
+puttime(Dosdir *d)
+{
+	Tm *t = localtime(time(0));
+	ushort x;
+
+	x = (t->hour<<11) | (t->min<<5) | (t->sec>>1);
+	d->time[0] = x;
+	d->time[1] = x>>8;
+	x = ((t->year-80)<<9) | ((t->mon+1)<<5) | t->mday;
+	d->date[0] = x;
+	d->date[1] = x>>8;
+}
+
+void
+addrname(uchar *entry, Dir *dir, char *name, ulong start)
+{
+	char *s;
+	Dosdir *d;
+
+	s = strrchr(name, '/');
+	if(s)
+		s++;
+	else
+		s = name;
+
+	d = (Dosdir*)entry;
+	putname(s, d);
+	if(strcmp(s, "9load") == 0)
+		d->attr = DSYSTEM;
+	else
+		d->attr = 0;
+	puttime(d);
+	d->start[0] = start;
+	d->start[1] = start>>8;
+	d->length[0] = dir->length;
+	d->length[1] = dir->length>>8;
+	d->length[2] = dir->length>>16;
+	d->length[3] = dir->length>>24;
+}