#include #include #include #include #include #include #define stat xv6_stat // avoid clash with host struct stat #include "types.h" #include "fs.h" #include "stat.h" #include "param.h" #ifndef _LP64 #error "Integers are not 32 bits" #endif int nblocks = 985; int nlog = LOGSIZE; int ninodes = 200; int size = 1024; int fsfd; struct superblock sb; char zeroes[512]; uint freeblock; uint usedblocks; uint bitblocks; uint freeinode = 1; void balloc(int); void wsect(uint, void*); void winode(uint, struct dinode*); void rinode(uint inum, struct dinode *ip); void rsect(uint sec, void *buf); uint ialloc(ushort type); void iappend(uint inum, void *p, int n); // convert to intel byte order ushort xshort(ushort x) { ushort y; uchar *a = (uchar*)&y; a[0] = x; a[1] = x >> 8; return y; } uint xint(uint x) { uint y; uchar *a = (uchar*)&y; a[0] = x; a[1] = x >> 8; a[2] = x >> 16; a[3] = x >> 24; return y; } int main(int argc, char *argv[]) { int i, cc, fd; uint rootino, inum, off; struct dirent de; char buf[512]; struct dinode din; if(argc < 2){ fprintf(stderr, "Usage: mkfs fs.img files...\n"); exit(1); } assert((512 % sizeof(struct dinode)) == 0); assert((512 % sizeof(struct dirent)) == 0); fsfd = open(argv[1], O_RDWR|O_CREAT|O_TRUNC, 0666); if(fsfd < 0){ perror(argv[1]); exit(1); } sb.size = xint(size); sb.nblocks = xint(nblocks); // so whole disk is size sectors sb.ninodes = xint(ninodes); sb.nlog = xint(nlog); bitblocks = size/(512*8) + 1; usedblocks = ninodes / IPB + 3 + bitblocks; freeblock = usedblocks; printf("used %d (bit %d ninode %zu) free %u log %u total %d\n", usedblocks, bitblocks, ninodes/IPB + 1, freeblock, nlog, nblocks+usedblocks+nlog); assert(nblocks + usedblocks + nlog == size); for(i = 0; i < nblocks + usedblocks + nlog; i++) wsect(i, zeroes); memset(buf, 0, sizeof(buf)); memmove(buf, &sb, sizeof(sb)); wsect(1, buf); rootino = ialloc(T_DIR); assert(rootino == ROOTINO); bzero(&de, sizeof(de)); de.inum = xshort(rootino); strcpy(de.name, "."); iappend(rootino, &de, sizeof(de)); bzero(&de, sizeof(de)); de.inum = xshort(rootino); strcpy(de.name, ".."); iappend(rootino, &de, sizeof(de)); for(i = 2; i < argc; i++){ assert(index(argv[i], '/') == 0); if((fd = open(argv[i], 0)) < 0){ perror(argv[i]); exit(1); } // Skip leading _ in name when writing to file system. // The binaries are named _rm, _cat, etc. to keep the // build operating system from trying to execute them // in place of system binaries like rm and cat. if(argv[i][0] == '_') ++argv[i]; inum = ialloc(T_FILE); bzero(&de, sizeof(de)); de.inum = xshort(inum); strncpy(de.name, argv[i], DIRSIZ); iappend(rootino, &de, sizeof(de)); while((cc = read(fd, buf, sizeof(buf))) > 0) iappend(inum, buf, cc); close(fd); } // fix size of root inode dir rinode(rootino, &din); off = xint(din.size); off = ((off/BSIZE) + 1) * BSIZE; din.size = xint(off); winode(rootino, &din); balloc(usedblocks); exit(0); } void wsect(uint sec, void *buf) { if(lseek(fsfd, sec * 512L, 0) != sec * 512L){ perror("lseek"); exit(1); } if(write(fsfd, buf, 512) != 512){ perror("write"); exit(1); } } uint i2b(uint inum) { return (inum / IPB) + 2; } void winode(uint inum, struct dinode *ip) { char buf[512]; uint bn; struct dinode *dip; bn = i2b(inum); rsect(bn, buf); dip = ((struct dinode*)buf) + (inum % IPB); *dip = *ip; wsect(bn, buf); } void rinode(uint inum, struct dinode *ip) { char buf[512]; uint bn; struct dinode *dip; bn = i2b(inum); rsect(bn, buf); dip = ((struct dinode*)buf) + (inum % IPB); *ip = *dip; } void rsect(uint sec, void *buf) { if(lseek(fsfd, sec * 512L, 0) != sec * 512L){ perror("lseek"); exit(1); } if(read(fsfd, buf, 512) != 512){ perror("read"); exit(1); } } uint ialloc(ushort type) { uint inum = freeinode++; struct dinode din; bzero(&din, sizeof(din)); din.type = xshort(type); din.nlink = xshort(1); din.size = xint(0); winode(inum, &din); return inum; } void balloc(int used) { uchar buf[512]; int i; printf("balloc: first %d blocks have been allocated\n", used); assert(used < 512*8); bzero(buf, 512); for(i = 0; i < used; i++){ buf[i/8] = buf[i/8] | (0x1 << (i%8)); } printf("balloc: write bitmap block at sector %zu\n", ninodes/IPB + 3); wsect(ninodes / IPB + 3, buf); } #define min(a, b) ((a) < (b) ? (a) : (b)) void iappend(uint inum, void *xp, int n) { char *p = (char*)xp; uint fbn, off, n1; struct dinode din; char buf[512]; uint indirect[NINDIRECT]; uint x; rinode(inum, &din); off = xint(din.size); while(n > 0){ fbn = off / 512; assert(fbn < MAXFILE); if(fbn < NDIRECT){ if(xint(din.addrs[fbn]) == 0){ din.addrs[fbn] = xint(freeblock++); usedblocks++; } x = xint(din.addrs[fbn]); } else { if(xint(din.addrs[NDIRECT]) == 0){ // printf("allocate indirect block\n"); din.addrs[NDIRECT] = xint(freeblock++); usedblocks++; } // printf("read indirect block\n"); rsect(xint(din.addrs[NDIRECT]), (char*)indirect); if(indirect[fbn - NDIRECT] == 0){ indirect[fbn - NDIRECT] = xint(freeblock++); usedblocks++; wsect(xint(din.addrs[NDIRECT]), (char*)indirect); } x = xint(indirect[fbn-NDIRECT]); } n1 = min(n, (fbn + 1) * 512 - off); rsect(x, buf); bcopy(p, buf + off - (fbn * 512), n1); wsect(x, buf); n -= n1; off += n1; p += n1; } din.size = xint(off); winode(inum, &din); }