139 lines
2.4 KiB
C
139 lines
2.4 KiB
C
#include <u.h>
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#include <libc.h>
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#include <auth.h>
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#include <fcall.h>
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#include "tapefs.h"
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/*
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* File system for cpio tapes (read-only)
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*/
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#define TBLOCK 512
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#define NBLOCK 40 /* maximum blocksize */
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#define DBLOCK 20 /* default blocksize */
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#define TNAMSIZ 100
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union hblock {
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char dummy[TBLOCK];
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char tbuf[Maxbuf];
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struct header {
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char magic[6];
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char dev[6];
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char ino[6];
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char mode[6];
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char uid[6];
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char gid[6];
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char nlink[6];
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char rdev[6];
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char mtime[11];
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char namesize[6];
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char size[11];
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} dbuf;
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struct hname {
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struct header x;
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char name[1];
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} nbuf;
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} dblock;
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int tapefile;
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vlong getoct(char*, int);
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void
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populate(char *name)
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{
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vlong offset;
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long isabs, magic, namesize, mode;
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Fileinf f;
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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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replete = 1;
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for (offset = 0;;) {
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seek(tapefile, offset, 0);
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if (read(tapefile, (char *)&dblock.dbuf, TBLOCK)<TBLOCK)
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break;
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magic = getoct(dblock.dbuf.magic, sizeof(dblock.dbuf.magic));
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if (magic != 070707){
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print("%lo\n", magic);
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error("out of phase--get help");
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}
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if (dblock.nbuf.name[0]=='\0' || strcmp(dblock.nbuf.name, "TRAILER!!!")==0)
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break;
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mode = getoct(dblock.dbuf.mode, sizeof(dblock.dbuf.mode));
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f.mode = mode&0777;
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switch(mode & 0170000) {
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case 0040000:
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f.mode |= DMDIR;
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break;
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case 0100000:
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break;
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default:
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f.mode = 0;
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break;
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}
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f.uid = getoct(dblock.dbuf.uid, sizeof(dblock.dbuf.uid));
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f.gid = getoct(dblock.dbuf.gid, sizeof(dblock.dbuf.gid));
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f.size = getoct(dblock.dbuf.size, sizeof(dblock.dbuf.size));
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f.mdate = getoct(dblock.dbuf.mtime, sizeof(dblock.dbuf.mtime));
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namesize = getoct(dblock.dbuf.namesize, sizeof(dblock.dbuf.namesize));
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f.addr = offset+sizeof(struct header)+namesize;
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isabs = dblock.nbuf.name[0]=='/';
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f.name = &dblock.nbuf.name[isabs];
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poppath(f, 1);
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offset += sizeof(struct header)+namesize+f.size;
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}
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}
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vlong
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getoct(char *p, int l)
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{
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vlong r;
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for (r=0; l>0; p++, l--){
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r <<= 3;
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r += *p-'0';
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}
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return 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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seek(tapefile, r->addr+off, 0);
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if (cnt>sizeof(dblock.tbuf))
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error("read too big");
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read(tapefile, dblock.tbuf, cnt);
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return dblock.tbuf;
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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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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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}
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