ref: 556618eb07d1ac6e2c629a60acd53c45d53261be
dir: /sys/src/cmd/tapefs/32vfs.c/
/* * Vax 32V Unix filesystem (same as pre-FFS Berkeley) */ #include <u.h> #include <libc.h> #include <auth.h> #include <fcall.h> #include "tapefs.h" /* * v32 disk inode */ #define VNADDR 13 #define VFMT 0160000 #define VIFREG 0100000 #define VIFDIR 0040000 #define VIFCHR 0120000 #define VIFBLK 0160000 #define VMODE 0777 #define VSUPERB 1 #define VROOT 2 /* root inode */ #define VNAMELEN 14 #define MAXBLSIZE 1024 int BLSIZE; #define LINOPB (BLSIZE/sizeof(struct v32dinode)) #define LNINDIR (BLSIZE/4) #define MAXLNINDIR (MAXBLSIZE/4) struct v32dinode { unsigned char flags[2]; unsigned char nlinks[2]; unsigned char uid[2]; unsigned char gid[2]; unsigned char size[4]; unsigned char addr[40]; unsigned char atime[4]; unsigned char mtime[4]; unsigned char ctime[4]; }; struct v32dir { uchar ino[2]; char name[VNAMELEN]; }; int tapefile; Fileinf iget(int ino); long bmap(Ram *r, long bno); void getblk(Ram *r, long bno, char *buf); void populate(char *name) { Fileinf f; BLSIZE = 512; /* 32v */ if(blocksize){ /* 1024 for 4.1BSD */ if(blocksize != 512 && blocksize != 1024) error("bad block size"); BLSIZE = blocksize; } replete = 0; tapefile = open(name, OREAD); if (tapefile<0) error("Can't open argument file"); f = iget(VROOT); ram->perm = f.mode; ram->mtime = f.mdate; ram->addr = f.addr; ram->data = f.data; ram->ndata = f.size; } void popdir(Ram *r) { int i, ino; char *cp; struct v32dir *dp; Fileinf f; char name[VNAMELEN+1]; cp = 0; for (i=0; i<r->ndata; i+=sizeof(struct v32dir)) { if (i%BLSIZE==0) cp = doread(r, i, BLSIZE); dp = (struct v32dir *)(cp+i%BLSIZE); ino = g2byte(dp->ino); if (strcmp(dp->name, ".")==0 || strcmp(dp->name, "..")==0) continue; if (ino==0) continue; f = iget(ino); strncpy(name, dp->name, VNAMELEN); name[VNAMELEN] = '\0'; f.name = name; popfile(r, f); } r->replete = 1; } void dotrunc(Ram *r) { USED(r); } void docreate(Ram *r) { USED(r); } char * doread(Ram *r, vlong off, long cnt) { static char buf[Maxbuf+MAXBLSIZE]; int bno, i; bno = off/BLSIZE; off -= bno*BLSIZE; if (cnt>Maxbuf) error("count too large"); if (off) cnt += off; i = 0; while (cnt>0) { getblk(r, bno, &buf[i*BLSIZE]); cnt -= BLSIZE; bno++; i++; } return buf; } 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; } /* * fetch an i-node * -- no sanity check for now * -- magic inode-to-disk-block stuff here */ Fileinf iget(int ino) { char buf[MAXBLSIZE]; struct v32dinode *dp; long flags, i; Fileinf f; seek(tapefile, BLSIZE*((ino-1)/LINOPB + VSUPERB + 1), 0); if (read(tapefile, buf, BLSIZE) != BLSIZE) error("Can't read inode"); dp = ((struct v32dinode *)buf) + ((ino-1)%LINOPB); flags = g2byte(dp->flags); f.size = g4byte(dp->size); if ((flags&VFMT)==VIFCHR || (flags&VFMT)==VIFBLK) f.size = 0; f.data = emalloc(VNADDR*sizeof(long)); for (i = 0; i < VNADDR; i++) ((long*)f.data)[i] = g3byte(dp->addr+3*i); f.mode = flags & VMODE; if ((flags&VFMT)==VIFDIR) f.mode |= DMDIR; f.uid = g2byte(dp->uid); f.gid = g2byte(dp->gid); f.mdate = g4byte(dp->mtime); return f; } void getblk(Ram *r, long bno, char *buf) { long dbno; if ((dbno = bmap(r, bno)) == 0) { memset(buf, 0, BLSIZE); return; } seek(tapefile, dbno*BLSIZE, 0); if (read(tapefile, buf, BLSIZE) != BLSIZE) error("bad read"); } /* * logical to physical block * only singly-indirect files for now */ long bmap(Ram *r, long bno) { unsigned char indbuf[MAXLNINDIR][4]; if (bno < VNADDR-3) return ((long*)r->data)[bno]; if (bno < VNADDR*LNINDIR) { seek(tapefile, ((long *)r->data)[(bno-(VNADDR-3))/LNINDIR]*BLSIZE, 0); if (read(tapefile, (char *)indbuf, BLSIZE) != BLSIZE) return 0; return ((indbuf[bno%LNINDIR][1]<<8) + indbuf[bno%LNINDIR][0]); } return 0; }