1 /* 2 * 10th edition 4K file system 3 */ 4 #include <u.h> 5 #include <libc.h> 6 #include <auth.h> 7 #include <fcall.h> 8 #include "tapefs.h" 9 10 /* 11 * v10 disk inode 12 */ 13 #define VNADDR 13 14 #define VFMT 0160000 15 #define VIFREG 0100000 16 #define VIFDIR 0040000 17 #define VIFCHR 0120000 18 #define VIFBLK 0160000 19 #define VMODE 0777 20 #define VSUPERB 1 21 #define VROOT 2 /* root inode */ 22 #define VNAMELEN 14 23 #define BLSIZE 4096 24 #define LINOPB (BLSIZE/sizeof(struct v10dinode)) 25 #define LNINDIR (BLSIZE/sizeof(unsigned long)) 26 27 struct v10dinode { 28 unsigned char flags[2]; 29 unsigned char nlinks[2]; 30 unsigned char uid[2]; 31 unsigned char gid[2]; 32 unsigned char size[4]; 33 unsigned char addr[40]; 34 unsigned char atime[4]; 35 unsigned char mtime[4]; 36 unsigned char ctime[4]; 37 }; 38 39 struct v10dir { 40 uchar ino[2]; 41 char name[VNAMELEN]; 42 }; 43 44 int tapefile; 45 vlong tapelen; 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 Dir *d; 55 56 replete = 0; 57 tapefile = open(name, OREAD); 58 if (tapefile<0) 59 error("Can't open argument file"); 60 if ((d=dirfstat(tapefile)) == nil) 61 error("dirfstat"); 62 tapelen = d->length; 63 free(d); 64 f = iget(VROOT); 65 ram->perm = f.mode; 66 ram->mtime = f.mdate; 67 ram->addr = f.addr; 68 ram->data = f.data; 69 ram->ndata = f.size; 70 } 71 72 void 73 popdir(Ram *r) 74 { 75 int i, ino; 76 char *cp; 77 struct v10dir *dp; 78 Fileinf f; 79 char name[VNAMELEN+1]; 80 81 cp = 0; 82 for (i=0; i<r->ndata; i+=sizeof(struct v10dir)) { 83 if (i%BLSIZE==0) 84 cp = doread(r, i, BLSIZE); 85 dp = (struct v10dir *)(cp+i%BLSIZE); 86 ino = g2byte(dp->ino); 87 if (strcmp(dp->name, ".")==0 || strcmp(dp->name, "..")==0) 88 continue; 89 if (ino==0) 90 continue; 91 f = iget(ino); 92 strncpy(name, dp->name, VNAMELEN); 93 name[VNAMELEN] = '\0'; 94 f.name = name; 95 popfile(r, f); 96 } 97 r->replete = 1; 98 } 99 100 void 101 dotrunc(Ram *r) 102 { 103 USED(r); 104 } 105 106 void 107 docreate(Ram *r) 108 { 109 USED(r); 110 } 111 112 char * 113 doread(Ram *r, vlong off, long cnt) 114 { 115 static char buf[Maxbuf+BLSIZE]; 116 int bno, i; 117 118 bno = off/BLSIZE; 119 off -= bno*BLSIZE; 120 if (cnt>Maxbuf) 121 error("count too large"); 122 if (off) 123 cnt += off; 124 i = 0; 125 while (cnt>0) { 126 getblk(r, bno, &buf[i*BLSIZE]); 127 cnt -= BLSIZE; 128 bno++; 129 i++; 130 } 131 return buf+off; 132 } 133 134 void 135 dowrite(Ram *r, char *buf, long off, long cnt) 136 { 137 USED(r); USED(buf); USED(off); USED(cnt); 138 } 139 140 int 141 dopermw(Ram *r) 142 { 143 USED(r); 144 return 0; 145 } 146 147 /* 148 * fetch an i-node 149 * -- no sanity check for now 150 * -- magic inode-to-disk-block stuff here 151 */ 152 153 Fileinf 154 iget(int ino) 155 { 156 char buf[BLSIZE]; 157 struct v10dinode *dp; 158 long flags, i; 159 Fileinf f; 160 161 seek(tapefile, BLSIZE*((ino-1)/LINOPB + VSUPERB + 1), 0); 162 if (read(tapefile, buf, BLSIZE) != BLSIZE) 163 error("Can't read inode"); 164 dp = ((struct v10dinode *)buf) + ((ino-1)%LINOPB); 165 flags = g2byte(dp->flags); 166 f.size = g4byte(dp->size); 167 if ((flags&VFMT)==VIFCHR || (flags&VFMT)==VIFBLK) 168 f.size = 0; 169 f.data = emalloc(VNADDR*sizeof(long)); 170 for (i = 0; i < VNADDR; i++) 171 ((long*)f.data)[i] = g3byte(dp->addr+3*i); 172 f.mode = flags & VMODE; 173 if ((flags&VFMT)==VIFDIR) 174 f.mode |= DMDIR; 175 f.uid = g2byte(dp->uid); 176 f.gid = g2byte(dp->gid); 177 f.mdate = g4byte(dp->mtime); 178 return f; 179 } 180 181 void 182 getblk(Ram *r, long bno, char *buf) 183 { 184 long dbno; 185 186 if ((dbno = bmap(r, bno)) == 0) { 187 memset(buf, 0, BLSIZE); 188 return; 189 } 190 if ((vlong)(dbno+1)*BLSIZE > tapelen) { 191 fprint(2, "read past end of tape: %lld\n", (vlong)dbno*BLSIZE); 192 memset(buf, 0, BLSIZE); 193 return; 194 } 195 seek(tapefile, dbno*BLSIZE, 0); 196 if (readn(tapefile, buf, BLSIZE) != BLSIZE){ 197 fprint(2, "readn at %lld: %r\n", (vlong)dbno*BLSIZE); 198 error("bad read"); 199 } 200 } 201 202 /* 203 * logical to physical block 204 * only singly-indirect files for now 205 */ 206 207 long 208 bmap(Ram *r, long bno) 209 { 210 unsigned char indbuf[LNINDIR][sizeof(long)]; 211 212 if (bno < VNADDR-3) 213 return ((long*)r->data)[bno]; 214 if (bno < VNADDR*LNINDIR) { 215 seek(tapefile, ((long *)r->data)[(bno-(VNADDR-3))/LNINDIR+(VNADDR-3)]*BLSIZE, 0); 216 if (read(tapefile, (char *)indbuf, BLSIZE) != BLSIZE) 217 return 0; 218 return ((indbuf[(bno-(VNADDR-3))%LNINDIR][2]<<16) + (indbuf[(bno-(VNADDR-3))%LNINDIR][1]<<8) 219 + indbuf[(bno-(VNADDR-3))%LNINDIR][0]); 220 } 221 return 0; 222 } 223