v6fs.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, "..")==0) 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][0]; 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 <= V6NADDR*BLSIZE) { /* assume size predicts largeness of file */ 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, 0); 209 if (read(tapefile, (char *)indbuf, BLSIZE) != BLSIZE) 210 return 0; 211 return ((indbuf[bno%LNINDIR][1]<<8) + indbuf[bno%LNINDIR][0]); 212 } 213 return 0; 214 }