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 Fileinf iget(int ino); 46 long bmap(Ram *r, long bno); 47 void getblk(Ram *r, long bno, char *buf); 48 49 void 50 populate(char *name) 51 { 52 Fileinf f; 53 54 replete = 0; 55 tapefile = open(name, OREAD); 56 if (tapefile<0) 57 error("Can't open argument file"); 58 f = iget(VROOT); 59 ram->perm = f.mode; 60 ram->mtime = f.mdate; 61 ram->addr = f.addr; 62 ram->data = f.data; 63 ram->ndata = f.size; 64 } 65 66 void 67 popdir(Ram *r) 68 { 69 int i, ino; 70 char *cp; 71 struct v10dir *dp; 72 Fileinf f; 73 char name[VNAMELEN+1]; 74 75 cp = 0; 76 for (i=0; i<r->ndata; i+=sizeof(struct v10dir)) { 77 if (i%BLSIZE==0) 78 cp = doread(r, i, BLSIZE); 79 dp = (struct v10dir *)(cp+i%BLSIZE); 80 ino = g2byte(dp->ino); 81 if (strcmp(dp->name, ".")==0 || strcmp(dp->name, "..")==0) 82 continue; 83 if (ino==0) 84 continue; 85 f = iget(ino); 86 strncpy(name, dp->name, VNAMELEN); 87 name[VNAMELEN+1] = '\0'; 88 f.name = name; 89 popfile(r, f); 90 } 91 r->replete = 1; 92 } 93 94 void 95 dotrunc(Ram *r) 96 { 97 USED(r); 98 } 99 100 void 101 docreate(Ram *r) 102 { 103 USED(r); 104 } 105 106 char * 107 doread(Ram *r, vlong off, long cnt) 108 { 109 static char buf[Maxbuf+BLSIZE]; 110 int bno, i; 111 112 bno = off/BLSIZE; 113 off -= bno*BLSIZE; 114 if (cnt>Maxbuf) 115 error("count too large"); 116 if (off) 117 cnt += off; 118 i = 0; 119 while (cnt>0) { 120 getblk(r, bno, &buf[i*BLSIZE]); 121 cnt -= BLSIZE; 122 bno++; 123 i++; 124 } 125 return buf+off; 126 } 127 128 void 129 dowrite(Ram *r, char *buf, long off, long cnt) 130 { 131 USED(r); USED(buf); USED(off); USED(cnt); 132 } 133 134 int 135 dopermw(Ram *r) 136 { 137 USED(r); 138 return 0; 139 } 140 141 /* 142 * fetch an i-node 143 * -- no sanity check for now 144 * -- magic inode-to-disk-block stuff here 145 */ 146 147 Fileinf 148 iget(int ino) 149 { 150 char buf[BLSIZE]; 151 struct v10dinode *dp; 152 long flags, i; 153 Fileinf f; 154 155 seek(tapefile, BLSIZE*((ino-1)/LINOPB + VSUPERB + 1), 0); 156 if (read(tapefile, buf, BLSIZE) != BLSIZE) 157 error("Can't read inode"); 158 dp = ((struct v10dinode *)buf) + ((ino-1)%LINOPB); 159 flags = g2byte(dp->flags); 160 f.size = g4byte(dp->size); 161 if ((flags&VFMT)==VIFCHR || (flags&VFMT)==VIFBLK) 162 f.size = 0; 163 f.data = emalloc(VNADDR*sizeof(long)); 164 for (i = 0; i < VNADDR; i++) 165 ((long*)f.data)[i] = g3byte(dp->addr+3*i); 166 f.mode = flags & VMODE; 167 if ((flags&VFMT)==VIFDIR) 168 f.mode |= DMDIR; 169 f.uid = g2byte(dp->uid); 170 f.gid = g2byte(dp->gid); 171 f.mdate = g4byte(dp->mtime); 172 return f; 173 } 174 175 void 176 getblk(Ram *r, long bno, char *buf) 177 { 178 long dbno; 179 180 if ((dbno = bmap(r, bno)) == 0) { 181 memset(buf, 0, BLSIZE); 182 return; 183 } 184 seek(tapefile, dbno*BLSIZE, 0); 185 if (read(tapefile, buf, BLSIZE) != BLSIZE) 186 error("bad read"); 187 } 188 189 /* 190 * logical to physical block 191 * only singly-indirect files for now 192 */ 193 194 long 195 bmap(Ram *r, long bno) 196 { 197 unsigned char indbuf[LNINDIR][sizeof(long)]; 198 199 if (bno < VNADDR-3) 200 return ((long*)r->data)[bno]; 201 if (bno < VNADDR*LNINDIR) { 202 seek(tapefile, ((long *)r->data)[(bno-(VNADDR-3))/LNINDIR+(VNADDR-3)]*BLSIZE, 0); 203 if (read(tapefile, (char *)indbuf, BLSIZE) != BLSIZE) 204 return 0; 205 return ((indbuf[(bno-(VNADDR-3))%LNINDIR][2]<<16) + (indbuf[(bno-(VNADDR-3))%LNINDIR][1]<<8) 206 + indbuf[(bno-(VNADDR-3))%LNINDIR][0]); 207 } 208 return 0; 209 } 210