ref: 1132d1b9df4c9ea2b857fa9778fe6762cd81ded8
parent: 3d052eb2ea48a7ab6e0169077a3f5b133c7121df
author: cinap_lenrek <cinap_lenrek@felloff.net>
date: Thu Mar 16 20:45:48 EDT 2017
tapefs: handle more cpio formats (thanks qrstuv)
--- a/sys/man/4/tapefs
+++ b/sys/man/4/tapefs
@@ -61,10 +61,7 @@
.I Cpiofs
interprets
.B cpio
-tape images (constructed with
-.BI cpio 's
-.B c
-flag).
+tape images.
.PP
.I Tarfs
interprets
--- a/sys/src/cmd/tapefs/cpiofs.c
+++ b/sys/src/cmd/tapefs/cpiofs.c
@@ -1,7 +1,6 @@
#include <u.h>
#include <libc.h>
-#include <auth.h>
-#include <fcall.h>
+#include <bio.h>
#include "tapefs.h"
/*
@@ -8,93 +7,223 @@
* File system for cpio tapes (read-only)
*/
-#define TBLOCK 512
-#define NBLOCK 40 /* maximum blocksize */
-#define DBLOCK 20 /* default blocksize */
-#define TNAMSIZ 100
-
union hblock {- char dummy[TBLOCK];
char tbuf[Maxbuf];
- struct header {- char magic[6];
- char dev[6];
- char ino[6];
- char mode[6];
- char uid[6];
- char gid[6];
- char nlink[6];
- char rdev[6];
- char mtime[11];
- char namesize[6];
- char size[11];
- } dbuf;
- struct hname {- struct header x;
- char name[1];
- } nbuf;
} dblock;
-int tapefile;
-vlong getoct(char*, int);
+typedef void HdrReader(Fileinf *);
+Biobuf *tape;
+
+static void
+addrfatal(char *fmt, va_list arg)
+{+ char buf[1024];
+
+ vseprint(buf, buf+sizeof(buf), fmt, arg);
+ fprint(2, "%s: %#llx: %s\n", argv0, Bseek(tape, 0, 1), buf);
+ exits(buf);
+}
+
+static int
+egetc(void)
+{+ int c;
+
+ if((c = Bgetc(tape)) == Beof)
+ sysfatal("unexpected eof");+ if(c < 0)
+ sysfatal("read error: %r");+ return c;
+}
+
+static ushort
+rd16le()
+{+ ushort x;
+
+ return x = egetc(), x |= egetc()<<8;
+}
+
+static ulong
+rd3211()
+{+ ulong x;
+
+ return x = egetc()<<16, x |= egetc()<<24, x |= egetc(), x |= egetc()<<8;
+}
+
+/* sysvr3 and sysvr4 skip records with names longer than 256. pwb 1.0,
+32V, sysiii, sysvr1, and sysvr2 overrun their 256 byte buffer */
+static void
+rdpwb(Fileinf *f, ushort (*rd16)(void), ulong (*rd32)(void))
+{+ int namesz, n;
+ static char buf[256];
+
+ rd16(); /* dev */
+ rd16(); /* ino */
+ f->mode = rd16();
+ f->uid = rd16();
+ f->gid = rd16();
+ rd16(); /* nlink */
+ rd16(); /* rdev */
+ f->mdate = rd32();
+ namesz = rd16();
+ f->size = rd32();
+
+ /* namesz include the trailing nul */
+ if(namesz == 0)
+ sysfatal("name too small");+ if(namesz > sizeof(buf))
+ sysfatal("name too big");+
+ if((n = Bread(tape, buf, namesz)) < 0)
+ sysfatal("read error: %r");+ if(n < namesz)
+ sysfatal("unexpected eof");+
+ if(buf[n-1] != '\0')
+ sysfatal("no nul after file name");+ if((n = strlen(buf)) != namesz-1)
+ sysfatal("mismatched name length: saw %d; expected %d", n, namesz-1);+ f->name = buf;
+
+ /* skip padding */
+ if(Bseek(tape, 0, 1) & 1)
+ egetc();
+}
+
+static void
+rdpwb11(Fileinf *f)
+{+ rdpwb(f, rd16le, rd3211);
+}
+
+static vlong
+rdasc(int n)
+{+ vlong x;
+ int y;
+
+ for(x = 0; n > 0; n--) {+ if((y = egetc() - '0') & ~7)
+ sysfatal("not octal");+ x = x<<3 | y;
+ }
+ return x;
+}
+
+/* sysvr3 and sysvr4 skip records with names longer than 256. sysiii,
+sysvr1, and sysvr2 overrun their 256 byte buffer */
+static void
+rdsysiii(Fileinf *f)
+{+ int namesz, n;
+ static char buf[256];
+
+ rdasc(6); /* dev */
+ rdasc(6); /* ino */
+ f->mode = rdasc(6);
+ f->uid = rdasc(6);
+ f->gid = rdasc(6);
+ rdasc(6); /* nlink */
+ rdasc(6); /* rdev */
+ f->mdate = rdasc(11);
+ namesz = rdasc(6);
+ f->size = rdasc(11);
+
+ /* namesz includes the trailing nul */
+ if(namesz == 0)
+ sysfatal("name too small");+ if(namesz > sizeof (buf))
+ sysfatal("name too big");+
+ if((n = Bread(tape, buf, namesz)) < 0)
+ sysfatal("read error: %r");+ if(n < namesz)
+ sysfatal("unexpected eof");+
+ if(buf[n-1] != '\0')
+ sysfatal("no nul after file name");+ if((n = strlen(buf)) != namesz-1)
+ sysfatal("mismatched name length: saw %d; expected %d", n, namesz-1);+ f->name = buf;
+}
+
+static HdrReader *
+rdmagic(void)
+{+ uchar buf[6];
+
+ buf[0] = egetc();
+ buf[1] = egetc();
+ if(buf[0] == 0xc7 && buf[1] == 0x71)
+ return rdpwb11;
+
+ buf[2] = egetc();
+ buf[3] = egetc();
+ buf[4] = egetc();
+ buf[5] = egetc();
+ if(memcmp(buf, "070707", 6) == 0)
+ return rdsysiii;
+
+ sysfatal("Out of phase--get MERT help");+ return nil;
+}
+
void
populate(char *name)
{- vlong offset;
- long isabs, magic, namesize, mode;
+ HdrReader *rdhdr, *prevhdr;
Fileinf f;
- tapefile = open(name, OREAD);
- if (tapefile<0)
- error("Can't open argument file");- replete = 1;
- for (offset = 0;;) {- seek(tapefile, offset, 0);
- if (read(tapefile, (char *)&dblock.dbuf, TBLOCK)<TBLOCK)
+ /* the tape buffer may not be the ideal size for scanning the
+ record headers */
+ if((tape = Bopen(name, OREAD)) == nil)
+ sysfatal("Can't open argument file");+
+ extern void (*_sysfatal)(char *, va_list);
+ _sysfatal = addrfatal;
+
+ prevhdr = nil;
+ replete = 1;
+ for(;;) {+ /* sysiii and sysv implementations don't allow
+ multiple header types within a single tape, so we
+ won't either */
+ rdhdr = rdmagic();
+ if(prevhdr != nil && rdhdr != prevhdr)
+ sysfatal("mixed headers");+ rdhdr(&f);
+
+ while(f.name[0] == '/')
+ f.name++;
+ if(f.name[0] == '\0')
+ sysfatal("nameless record");+ if(strcmp(f.name, "TRAILER!!!") == 0)
break;
- magic = getoct(dblock.dbuf.magic, sizeof(dblock.dbuf.magic));
- if (magic != 070707){- print("%lo\n", magic);- error("out of phase--get help");- }
- if (dblock.nbuf.name[0]=='\0' || strcmp(dblock.nbuf.name, "TRAILER!!!")==0)
- break;
- mode = getoct(dblock.dbuf.mode, sizeof(dblock.dbuf.mode));
- f.mode = mode&0777;
- switch(mode & 0170000) {+ switch(f.mode & 0170000) {case 0040000:
- f.mode |= DMDIR;
+ f.mode = DMDIR | f.mode&0777;
break;
- case 0100000:
+ case 0100000: /* normal file */
+ case 0120000: /* symlink */
+ f.mode &= 0777;
break;
- default:
+ default: /* sockets, pipes, devices */
f.mode = 0;
break;
}
- f.uid = getoct(dblock.dbuf.uid, sizeof(dblock.dbuf.uid));
- f.gid = getoct(dblock.dbuf.gid, sizeof(dblock.dbuf.gid));
- f.size = getoct(dblock.dbuf.size, sizeof(dblock.dbuf.size));
- f.mdate = getoct(dblock.dbuf.mtime, sizeof(dblock.dbuf.mtime));
- namesize = getoct(dblock.dbuf.namesize, sizeof(dblock.dbuf.namesize));
- f.addr = offset+sizeof(struct header)+namesize;
- isabs = dblock.nbuf.name[0]=='/';
- f.name = &dblock.nbuf.name[isabs];
+ f.addr = Bseek(tape, 0, 1);
poppath(f, 1);
- offset += sizeof(struct header)+namesize+f.size;
- }
-}
-vlong
-getoct(char *p, int l)
-{- vlong r;
+ Bseek(tape, f.size, 1);
- for (r=0; l>0; p++, l--){- r <<= 3;
- r += *p-'0';
+ /* skip padding */
+ if(rdhdr == rdpwb11 && (Bseek(tape, 0, 1) & 1))
+ egetc();
}
- return r;
}
void
@@ -112,10 +241,10 @@
char *
doread(Ram *r, vlong off, long cnt)
{- seek(tapefile, r->addr+off, 0);
+ Bseek(tape, r->addr+off, 0);
if (cnt>sizeof(dblock.tbuf))
- error("read too big");- read(tapefile, dblock.tbuf, cnt);
+ sysfatal("read too big");+ Bread(tape, dblock.tbuf, cnt);
return dblock.tbuf;
}