tapefs: handle more cpio formats (thanks qrstuv)
This commit is contained in:
cinap_lenrek
parent
3d052eb2ea
commit
1132d1b9df
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@ -61,10 +61,7 @@ the VAX (512 byte block size, the default), and also pre-FFS Berkeley VAX system
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.I Cpiofs
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interprets
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.B cpio
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tape images (constructed with
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.BI cpio 's
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.B c
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flag).
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tape images.
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.PP
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.I Tarfs
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interprets
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@ -1,100 +1,229 @@
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#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 <bio.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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typedef void HdrReader(Fileinf *);
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Biobuf *tape;
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static void
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addrfatal(char *fmt, va_list arg)
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{
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char buf[1024];
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vseprint(buf, buf+sizeof(buf), fmt, arg);
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fprint(2, "%s: %#llx: %s\n", argv0, Bseek(tape, 0, 1), buf);
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exits(buf);
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}
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static int
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egetc(void)
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{
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int c;
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if((c = Bgetc(tape)) == Beof)
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sysfatal("unexpected eof");
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if(c < 0)
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sysfatal("read error: %r");
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return c;
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}
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static ushort
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rd16le()
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{
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ushort x;
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return x = egetc(), x |= egetc()<<8;
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}
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static ulong
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rd3211()
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{
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ulong x;
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return x = egetc()<<16, x |= egetc()<<24, x |= egetc(), x |= egetc()<<8;
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}
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/* sysvr3 and sysvr4 skip records with names longer than 256. pwb 1.0,
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32V, sysiii, sysvr1, and sysvr2 overrun their 256 byte buffer */
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static void
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rdpwb(Fileinf *f, ushort (*rd16)(void), ulong (*rd32)(void))
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{
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int namesz, n;
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static char buf[256];
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rd16(); /* dev */
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rd16(); /* ino */
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f->mode = rd16();
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f->uid = rd16();
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f->gid = rd16();
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rd16(); /* nlink */
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rd16(); /* rdev */
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f->mdate = rd32();
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namesz = rd16();
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f->size = rd32();
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/* namesz include the trailing nul */
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if(namesz == 0)
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sysfatal("name too small");
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if(namesz > sizeof(buf))
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sysfatal("name too big");
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if((n = Bread(tape, buf, namesz)) < 0)
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sysfatal("read error: %r");
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if(n < namesz)
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sysfatal("unexpected eof");
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if(buf[n-1] != '\0')
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sysfatal("no nul after file name");
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if((n = strlen(buf)) != namesz-1)
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sysfatal("mismatched name length: saw %d; expected %d", n, namesz-1);
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f->name = buf;
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/* skip padding */
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if(Bseek(tape, 0, 1) & 1)
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egetc();
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}
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static void
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rdpwb11(Fileinf *f)
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{
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rdpwb(f, rd16le, rd3211);
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}
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static vlong
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rdasc(int n)
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{
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vlong x;
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int y;
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for(x = 0; n > 0; n--) {
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if((y = egetc() - '0') & ~7)
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sysfatal("not octal");
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x = x<<3 | y;
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}
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return x;
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}
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/* sysvr3 and sysvr4 skip records with names longer than 256. sysiii,
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sysvr1, and sysvr2 overrun their 256 byte buffer */
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static void
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rdsysiii(Fileinf *f)
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{
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int namesz, n;
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static char buf[256];
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rdasc(6); /* dev */
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rdasc(6); /* ino */
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f->mode = rdasc(6);
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f->uid = rdasc(6);
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f->gid = rdasc(6);
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rdasc(6); /* nlink */
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rdasc(6); /* rdev */
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f->mdate = rdasc(11);
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namesz = rdasc(6);
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f->size = rdasc(11);
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/* namesz includes the trailing nul */
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if(namesz == 0)
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sysfatal("name too small");
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if(namesz > sizeof (buf))
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sysfatal("name too big");
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if((n = Bread(tape, buf, namesz)) < 0)
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sysfatal("read error: %r");
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if(n < namesz)
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sysfatal("unexpected eof");
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if(buf[n-1] != '\0')
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sysfatal("no nul after file name");
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if((n = strlen(buf)) != namesz-1)
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sysfatal("mismatched name length: saw %d; expected %d", n, namesz-1);
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f->name = buf;
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}
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static HdrReader *
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rdmagic(void)
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{
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uchar buf[6];
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buf[0] = egetc();
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buf[1] = egetc();
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if(buf[0] == 0xc7 && buf[1] == 0x71)
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return rdpwb11;
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buf[2] = egetc();
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buf[3] = egetc();
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buf[4] = egetc();
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buf[5] = egetc();
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if(memcmp(buf, "070707", 6) == 0)
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return rdsysiii;
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sysfatal("Out of phase--get MERT help");
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return nil;
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}
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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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HdrReader *rdhdr, *prevhdr;
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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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/* the tape buffer may not be the ideal size for scanning the
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record headers */
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if((tape = Bopen(name, OREAD)) == nil)
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sysfatal("Can't open argument file");
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extern void (*_sysfatal)(char *, va_list);
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_sysfatal = addrfatal;
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prevhdr = nil;
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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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for(;;) {
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/* sysiii and sysv implementations don't allow
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multiple header types within a single tape, so we
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won't either */
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rdhdr = rdmagic();
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if(prevhdr != nil && rdhdr != prevhdr)
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sysfatal("mixed headers");
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rdhdr(&f);
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while(f.name[0] == '/')
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f.name++;
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if(f.name[0] == '\0')
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sysfatal("nameless record");
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if(strcmp(f.name, "TRAILER!!!") == 0)
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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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switch(f.mode & 0170000) {
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case 0040000:
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f.mode |= DMDIR;
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f.mode = DMDIR | f.mode&0777;
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break;
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case 0100000:
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case 0100000: /* normal file */
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case 0120000: /* symlink */
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f.mode &= 0777;
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break;
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default:
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default: /* sockets, pipes, devices */
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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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f.addr = Bseek(tape, 0, 1);
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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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Bseek(tape, f.size, 1);
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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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/* skip padding */
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if(rdhdr == rdpwb11 && (Bseek(tape, 0, 1) & 1))
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egetc();
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}
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return r;
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}
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void
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@ -112,10 +241,10 @@ docreate(Ram *r)
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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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Bseek(tape, 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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sysfatal("read too big");
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Bread(tape, dblock.tbuf, cnt);
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return dblock.tbuf;
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}
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