Subversion Repositories planix.SVN

#include <u.h>
#include <libc.h>
#include "tapefs.h"

/*
 * File system for tp tapes.  dectape versions have 192
 * entries, magtape have 496.  This treats the same
 * by ignoring entries with bad header checksums
 */

struct tp {
        unsigned char   name[32];
        unsigned char   mode[2];
        unsigned char   uid[1];
        unsigned char   gid[1];
        unsigned char   unused[1];
        unsigned char   size[3];
        unsigned char   tmod[4];
        unsigned char   taddress[2];
        unsigned char   unused2[16];
        unsigned char   checksum[2];
} dir[496+8];

char    buffer[8192];
int     tapefile;

void
populate(char *name)
{
        int i, isabs, badcksum, goodcksum;
        struct tp *tpp;
        Fileinf f;

        replete = 1;
        tapefile = open(name, OREAD);
        if (tapefile<0)
                error("Can't open argument file");
        read(tapefile, dir, sizeof dir);
        badcksum = goodcksum = 0;
        for (i=0, tpp=&dir[8]; i<496; i++, tpp++) {
                unsigned char *sp = (unsigned char *)tpp;
                int j, cksum = 0;
                for (j=0; j<32; j++, sp+=2)
                        cksum += sp[0] + (sp[1]<<8);
                cksum &= 0xFFFF;
                if (cksum!=0) {
                        badcksum++;
                        continue;
                }
                goodcksum++;
                if (tpp->name[0]=='\0')
                        continue;
                f.addr = tpp->taddress[0] + (tpp->taddress[1]<<8);
                if (f.addr==0)
                        continue;
                f.size = (tpp->size[0]<<16) + (tpp->size[1]<<0) + (tpp->size[2]<<8);
                f.mdate = (tpp->tmod[2]<<0) + (tpp->tmod[3]<<8)
                     +(tpp->tmod[0]<<16) + (tpp->tmod[1]<<24);
                f.mode = tpp->mode[0]&0777;
                f.uid = tpp->uid[0];
                f.gid = tpp->gid[0];
                isabs = tpp->name[0]=='/';
                f.name = (char *)tpp->name+isabs;
                poppath(f, 1);
        }
        fprint(2, "%d bad checksums, %d good\n", badcksum, goodcksum);
}

void
popdir(Ram *r)
{
        USED(r);
}

void
dotrunc(Ram *r)
{
        USED(r);
}

void
docreate(Ram *r)
{
        USED(r);
}

char *
doread(Ram *r, vlong off, long cnt)
{
        if (cnt>sizeof(buffer))
                print("count too big\n");
        seek(tapefile, 512*r->addr+off, 0);
        read(tapefile, buffer, cnt);
        return buffer;
}

void
dowrite(Ram *r, char *buf, long off, long cnt)
{
        USED(r); USED(buf); USED(off); USED(cnt);
}

int
dopermw(Ram *r)
{
        USED(r);
        return 0;
}