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	tv6fs.c - plan9port - [fork] Plan 9 from user space
	git clone git://src.adamsgaard.dk/plan9port
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	---
	tv6fs.c (4016B)
	---
	1 /*
	2 * old (V6 and before) PDP-11 Unix filesystem
	3 */
	4 #include <u.h>
	5 #include <libc.h>
	6 #include <auth.h>
	7 #include <fcall.h>
	8 #include "tapefs.h"
	9
	10 /*
	11 * v6 disk inode
	12 */
	13 #define V6NADDR 8
	14 #define V6FMT 0160000
	15 #define V6IFREG 0100000
	16 #define V6IFDIR 0140000
	17 #define V6IFCHR 0120000
	18 #define V6IFBLK 0160000
	19 #define V6MODE 0777
	20 #define V6LARGE 010000
	21 #define V6SUPERB 1
	22 #define V6ROOT 1 /* root inode */
	23 #define V6NAMELEN 14
	24 #define BLSIZE 512
	25 #define LINOPB (BLSIZE/sizeof(struct v6dinode))
	26 #define LNINDIR (BLSIZE/sizeof(unsigned short))
	27
	28 struct v6dinode {
	29 unsigned char flags[2];
	30 unsigned char nlinks;
	31 unsigned char uid;
	32 unsigned char gid;
	33 unsigned char hisize;
	34 unsigned char losize[2];
	35 unsigned char addr[V6NADDR][2];
	36 unsigned char atime[4]; /* pdp-11 order */
	37 unsigned char mtime[4]; /* pdp-11 order */
	38 };
	39
	40 struct v6dir {
	41 uchar ino[2];
	42 char name[V6NAMELEN];
	43 };
	44
	45 int tapefile;
	46 Fileinf iget(int ino);
	47 long bmap(Ram *r, long bno);
	48 void getblk(Ram r, long bno, char buf);
	49
	50 void
	51 populate(char *name)
	52 {
	53 Fileinf f;
	54
	55 replete = 0;
	56 tapefile = open(name, OREAD);
	57 if (tapefile<0)
	58 error("Can't open argument file");
	59 f = iget(V6ROOT);
	60 ram->perm = f.mode;
	61 ram->mtime = f.mdate;
	62 ram->addr = f.addr;
	63 ram->data = f.data;
	64 ram->ndata = f.size;
	65 }
	66
	67 void
	68 popdir(Ram *r)
	69 {
	70 int i, ino;
	71 char *cp;
	72 struct v6dir *dp;
	73 Fileinf f;
	74 char name[V6NAMELEN+1];
	75
	76 cp = 0;
	77 for (i=0; i<r->ndata; i+=sizeof(struct v6dir)) {
	78 if (i%BLSIZE==0)
	79 cp = doread(r, i, BLSIZE);
	80 dp = (struct v6dir *)(cp+i%BLSIZE);
	81 ino = dp->ino[0] + (dp->ino[1]<<8);
	82 if (strcmp(dp->name, ".")==0 \|\| strcmp(dp->name, "..")==…
	83 continue;
	84 if (ino==0)
	85 continue;
	86 f = iget(ino);
	87 strncpy(name, dp->name, V6NAMELEN);
	88 name[V6NAMELEN] = '\0';
	89 f.name = name;
	90 popfile(r, f);
	91 }
	92 r->replete = 1;
	93 }
	94
	95 void
	96 dotrunc(Ram *r)
	97 {
	98 USED(r);
	99 }
	100
	101 void
	102 docreate(Ram *r)
	103 {
	104 USED(r);
	105 }
	106
	107 char *
	108 doread(Ram *r, vlong off, long cnt)
	109 {
	110 static char buf[Maxbuf+BLSIZE];
	111 int bno, i;
	112
	113 bno = off/BLSIZE;
	114 off -= bno*BLSIZE;
	115 if (cnt>Maxbuf)
	116 error("count too large");
	117 if (off)
	118 cnt += off;
	119 i = 0;
	120 while (cnt>0) {
	121 getblk(r, bno, &buf[i*BLSIZE]);
	122 cnt -= BLSIZE;
	123 bno++;
	124 i++;
	125 }
	126 return buf;
	127 }
	128
	129 void
	130 dowrite(Ram r, char buf, long off, long cnt)
	131 {
	132 USED(r); USED(buf); USED(off); USED(cnt);
	133 }
	134
	135 int
	136 dopermw(Ram *r)
	137 {
	138 USED(r);
	139 return 0;
	140 }
	141
	142 /*
	143 * fetch an i-node
	144 * -- no sanity check for now
	145 * -- magic inode-to-disk-block stuff here
	146 */
	147
	148 Fileinf
	149 iget(int ino)
	150 {
	151 char buf[BLSIZE];
	152 struct v6dinode *dp;
	153 long flags, i;
	154 Fileinf f;
	155
	156 memset(&f, 0, sizeof f);
	157 seek(tapefile, BLSIZE*((ino-1)/LINOPB + V6SUPERB + 1), 0);
	158 if (read(tapefile, buf, BLSIZE) != BLSIZE)
	159 error("Can't read inode");
	160 dp = ((struct v6dinode *)buf) + ((ino-1)%LINOPB);
	161 flags = (dp->flags[1]<<8) + dp->flags[0];
	162 f.size = (dp->hisize << 16) + (dp->losize[1]<<8) + dp->losize[0];
	163 if ((flags&V6FMT)==V6IFCHR \|\| (flags&V6FMT)==V6IFBLK)
	164 f.size = 0;
	165 f.data = emalloc(V6NADDR*sizeof(ushort));
	166 for (i = 0; i < V6NADDR; i++)
	167 ((ushort*)f.data)[i] = (dp->addr[i][1]<<8) + dp->addr[i]…
	168 f.mode = flags & V6MODE;
	169 if ((flags&V6FMT)==V6IFDIR)
	170 f.mode \|= DMDIR;
	171 f.uid = dp->uid;
	172 f.gid = dp->gid;
	173 f.mdate = (dp->mtime[2]<<0) + (dp->mtime[3]<<8)
	174 +(dp->mtime[0]<<16) + (dp->mtime[1]<<24);
	175 return f;
	176 }
	177
	178 void
	179 getblk(Ram r, long bno, char buf)
	180 {
	181 long dbno;
	182
	183 if ((dbno = bmap(r, bno)) == 0) {
	184 memset(buf, 0, BLSIZE);
	185 return;
	186 }
	187 seek(tapefile, dbno*BLSIZE, 0);
	188 if (read(tapefile, buf, BLSIZE) != BLSIZE)
	189 error("bad read");
	190 }
	191
	192 /*
	193 * logical to physical block
	194 * only singly-indirect files for now
	195 */
	196
	197 long
	198 bmap(Ram *r, long bno)
	199 {
	200 unsigned char indbuf[LNINDIR][2];
	201
	202 if (r->ndata <= V6NADDRBLSIZE) { / assume size predicts…
	203 if (bno < V6NADDR)
	204 return ((ushort*)r->data)[bno];
	205 return 0;
	206 }
	207 if (bno < V6NADDR*LNINDIR) {
	208 seek(tapefile, ((ushort )r->data)[bno/LNINDIR]BLSIZE, …
	209 if (read(tapefile, (char *)indbuf, BLSIZE) != BLSIZE)
	210 return 0;
	211 return ((indbuf[bno%LNINDIR][1]<<8) + indbuf[bno%LNINDIR…
	212 }
	213 return 0;
	214 }