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