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#include <u.h>
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#include <libc.h>
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#include "tapefs.h"
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/*
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 * File system for tp tapes.  dectape versions have 192
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 * entries, magtape have 496.  This treats the same
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 * by ignoring entries with bad header checksums
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 */
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struct tp {
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	unsigned char	name[32];
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	unsigned char	mode[2];
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	unsigned char	uid[1];
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	unsigned char	gid[1];
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	unsigned char	unused[1];
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	unsigned char	size[3];
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	unsigned char	tmod[4];
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	unsigned char	taddress[2];
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	unsigned char	unused2[16];
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	unsigned char	checksum[2];
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} dir[496+8];
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char	buffer[8192];
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int	tapefile;
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void
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populate(char *name)
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{
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	int i, isabs, badcksum, goodcksum;
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	struct tp *tpp;
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	Fileinf f;
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	replete = 1;
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	tapefile = open(name, OREAD);
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	if (tapefile<0)
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		error("Can't open argument file");
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	read(tapefile, dir, sizeof dir);
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	badcksum = goodcksum = 0;
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	for (i=0, tpp=&dir[8]; i<496; i++, tpp++) {
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		unsigned char *sp = (unsigned char *)tpp;
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		int j, cksum = 0;
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		for (j=0; j<32; j++, sp+=2)
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			cksum += sp[0] + (sp[1]<<8);
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		cksum &= 0xFFFF;
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		if (cksum!=0) {
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			badcksum++;
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			continue;
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		}
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		goodcksum++;
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		if (tpp->name[0]=='\0')
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			continue;
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		f.addr = tpp->taddress[0] + (tpp->taddress[1]<<8);
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		if (f.addr==0)
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			continue;
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		f.size = (tpp->size[0]<<16) + (tpp->size[1]<<0) + (tpp->size[2]<<8);
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		f.mdate = (tpp->tmod[2]<<0) + (tpp->tmod[3]<<8)
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		     +(tpp->tmod[0]<<16) + (tpp->tmod[1]<<24);
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		f.mode = tpp->mode[0]&0777;
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		f.uid = tpp->uid[0];
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		f.gid = tpp->gid[0];
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		isabs = tpp->name[0]=='/';
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		f.name = (char *)tpp->name+isabs;
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		poppath(f, 1);
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	}
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	fprint(2, "%d bad checksums, %d good\n", badcksum, goodcksum);
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}
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void
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popdir(Ram *r)
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{
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	USED(r);
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}
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void
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dotrunc(Ram *r)
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{
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	USED(r);
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}
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void
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docreate(Ram *r)
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{
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	USED(r);
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}
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char *
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doread(Ram *r, vlong off, long cnt)
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{
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	if (cnt>sizeof(buffer))
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		print("count too big\n");
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	seek(tapefile, 512*r->addr+off, 0);
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	read(tapefile, buffer, cnt);
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	return buffer;
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}
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void
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dowrite(Ram *r, char *buf, long off, long cnt)
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{
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	USED(r); USED(buf); USED(off); USED(cnt);
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}
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int
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dopermw(Ram *r)
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{
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	USED(r);
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	return 0;
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}