/* vi: set ts=4: * * mke2fs.c - Create an ext2 filesystem image. * * Copyright 2006, 2007 Rob Landley <rob@landley.net> * * Not in SUSv3. // Still to go: "E:jJ:L:m:O:" USE_MKE2FS(NEWTOY(mke2fs, "<1>2g:Fnqm#N#i#b#", TOYFLAG_SBIN)) config MKE2FS bool "mke2fs" default n help usage: mke2fs [-Fnq] [-b ###] [-N|i ###] [-m ###] device Create an ext2 filesystem on a block device or filesystem image. -F Force to run on a mounted device -n Don't write to device -q Quiet (no output) -b size Block size (1024, 2048, or 4096) -N inodes Allocate this many inodes -i bytes Allocate one inode for every XXX bytes of device -m percent Reserve this percent of filesystem space for root user config MKE2FS_JOURNAL bool "Journaling support (ext3)" default n depends on MKE2FS help usage: [-j] [-J size=###,device=XXX] -j Create journal (ext3) -J Journal options size: Number of blocks (1024-102400) device: Specify an external journal config MKE2FS_GEN bool "Generate (gene2fs)" default n depends on MKE2FS help usage: gene2fs [options] device filename The [options] are the same as mke2fs. config MKE2FS_LABEL bool "Label support" default n depends on MKE2FS help usage: mke2fs [-L label] [-M path] [-o string] -L Volume label -M Path to mount point -o Created by config MKE2FS_EXTENDED bool "Extended options" default n depends on MKE2FS help usage: mke2fs [-E stride=###] [-O option[,option]] -E stride= Set RAID stripe size (in blocks) -O [opts] Specify fewer ext2 option flags (for old kernels) All of these are on by default (as appropriate) none Clear default options (all but journaling) dir_index Use htree indexes for large directories filetype Store file type info in directory entry has_journal Set by -j journal_dev Set by -J device=XXX sparse_super Don't allocate huge numbers of redundant superblocks */ #include "toys.h" DEFINE_GLOBALS( // Command line arguments. long blocksize; long bytes_per_inode; long inodes; // Total inodes in filesystem. long reserved_percent; // Integer precent of space to reserve for root. char *gendir; // Where to read dirtree from. // Internal data. struct dirtree *dt; // Tree of files to copy into the new filesystem. unsigned treeblocks; // Blocks used by dt unsigned treeinodes; // Inodes used by dt unsigned blocks; // Total blocks in the filesystem. unsigned freeblocks; // Free blocks in the filesystem. unsigned inodespg; // Inodes per group unsigned groups; // Total number of block groups. unsigned blockbits; // Bits per block. (Also blocks per group.) // For gene2fs unsigned nextblock; // Next data block to allocate unsigned nextgroup; // Next group we'll be allocating from int fsfd; // File descriptor of filesystem (to output to). struct ext2_superblock sb; ) // Shortcut to our global data structure, since we use it so much. #define TT this.mke2fs #define INODES_RESERVED 10 static uint32_t div_round_up(uint32_t a, uint32_t b) { uint32_t c = a/b; if (a%b) c++; return c; } // Calculate data blocks plus index blocks needed to hold a file. static uint32_t file_blocks_used(uint64_t size, uint32_t *blocklist) { uint32_t dblocks = (uint32_t)((size+(TT.blocksize-1))/TT.blocksize); uint32_t idx=TT.blocksize/4, iblocks=0, diblocks=0, tiblocks=0; // Fill out index blocks in inode. if (blocklist) { int i; // Direct index blocks for (i=0; i<13 && i<dblocks; i++) blocklist[i] = i; // Singly indirect index blocks if (dblocks > 13+idx) blocklist[13] = 13+idx; // Doubly indirect index blocks idx = 13 + idx + (idx*idx); if (dblocks > idx) blocklist[14] = idx; return 0; } // Account for direct, singly, doubly, and triply indirect index blocks if (dblocks > 12) { iblocks = ((dblocks-13)/idx)+1; if (iblocks > 1) { diblocks = ((iblocks-2)/idx)+1; if (diblocks > 1) tiblocks = ((diblocks-2)/idx)+1; } } return dblocks + iblocks + diblocks + tiblocks; } // Use the parent pointer to iterate through the tree non-recursively. static struct dirtree *treenext(struct dirtree *this) { while (this && !this->next) this = this->parent; if (this) this = this->next; return this; } // Recursively calculate the number of blocks used by each inode in the tree. // Returns blocks used by this directory, assigns bytes used to *size. // Writes total block count to TT.treeblocks and inode count to TT.treeinodes. static long check_treesize(struct dirtree *that, off_t *size) { long blocks; while (that) { *size += sizeof(struct ext2_dentry) + strlen(that->name); if (that->child) that->st.st_blocks = check_treesize(that->child, &that->st.st_size); else if (S_ISREG(that->st.st_mode)) { that->st.st_blocks = file_blocks_used(that->st.st_size, 0); TT.treeblocks += that->st.st_blocks; } that = that->next; } TT.treeblocks += blocks = file_blocks_used(*size, 0); TT.treeinodes++; return blocks; } // Calculate inode numbers and link counts. // // To do this right I need to copy the tree and sort it, but here's a really // ugly n^2 way of dealing with the problem that doesn't scale well to large // numbers of files (> 100,000) but can be done in very little code. // This rewrites inode numbers to their final values, allocating depth first. static void check_treelinks(struct dirtree *tree) { struct dirtree *current=tree, *that; long inode = INODES_RESERVED; while (current) { ++inode; // Since we can't hardlink to directories, we know their link count. if (S_ISDIR(current->st.st_mode)) current->st.st_nlink = 2; else { dev_t new = current->st.st_dev; if (!new) continue; // Look for other copies of current node current->st.st_nlink = 0; for (that = tree; that; that = treenext(that)) { if (current->st.st_ino == that->st.st_ino && current->st.st_dev == that->st.st_dev) { current->st.st_nlink++; current->st.st_ino = inode; } } } current->st.st_ino = inode; current = treenext(current); } } // According to http://www.opengroup.org/onlinepubs/9629399/apdxa.htm // we should generate a uuid structure by reading a clock with 100 nanosecond // precision, normalizing it to the start of the gregorian calendar in 1582, // and looking up our eth0 mac address. // // On the other hand, we have 128 bits to come up with a unique identifier, of // which 6 have a defined value. /dev/urandom it is. static void create_uuid(char *uuid) { // Read 128 random bits int fd = xopen("/dev/urandom", O_RDONLY); xreadall(fd, uuid, 16); close(fd); // Claim to be a DCE format UUID. uuid[6] = (uuid[6] & 0x0F) | 0x40; uuid[8] = (uuid[8] & 0x3F) | 0x80; // rfc2518 section 6.4.1 suggests if we're not using a macaddr, we should // set bit 1 of the node ID, which is the mac multicast bit. This means we // should never collide with anybody actually using a macaddr. uuid[11] = uuid[11] | 128; } // Calculate inodes per group from total inodes. static uint32_t get_inodespg(uint32_t inodes) { uint32_t temp; // Round up to fill complete inode blocks. temp = (inodes + TT.groups - 1) / TT.groups; inodes = TT.blocksize/sizeof(struct ext2_inode); return ((temp + inodes - 1)/inodes)*inodes; } // Fill out superblock and TT structures. static void init_superblock(struct ext2_superblock *sb) { uint32_t temp; // Set log_block_size and log_frag_size. for (temp = 0; temp < 4; temp++) if (TT.blocksize == 1024<<temp) break; if (temp==4) error_exit("bad blocksize"); sb->log_block_size = sb->log_frag_size = SWAP_LE32(temp); // Fill out blocks_count, r_blocks_count, first_data_block sb->blocks_count = SWAP_LE32(TT.blocks); sb->free_blocks_count = SWAP_LE32(TT.freeblocks); temp = (TT.blocks * (uint64_t)TT.reserved_percent) / 100; sb->r_blocks_count = SWAP_LE32(temp); sb->first_data_block = SWAP_LE32(TT.blocksize == 1024 ? 1 : 0); // Set blocks_per_group and frags_per_group, which is the size of an // allocation bitmap that fits in one block (I.E. how many bits per block)? sb->blocks_per_group = sb->frags_per_group = SWAP_LE32(TT.blockbits); // Set inodes_per_group and total inodes_count sb->inodes_per_group = SWAP_LE32(TT.inodespg); sb->inodes_count = SWAP_LE32(TT.inodespg * TT.groups); // Determine free inodes. temp = TT.inodespg*TT.groups - INODES_RESERVED; if (temp < TT.treeinodes) error_exit("Not enough inodes.\n"); sb->free_inodes_count = SWAP_LE32(temp - TT.treeinodes); // Fill out the rest of the superblock. sb->max_mnt_count=0xFFFF; sb->wtime = sb->lastcheck = sb->mkfs_time = SWAP_LE32(time(NULL)); sb->magic = SWAP_LE32(0xEF53); sb->state = sb->errors = SWAP_LE16(1); sb->rev_level = SWAP_LE32(1); sb->first_ino = SWAP_LE32(INODES_RESERVED+1); sb->inode_size = SWAP_LE16(sizeof(struct ext2_inode)); sb->feature_incompat = SWAP_LE32(EXT2_FEATURE_INCOMPAT_FILETYPE); sb->feature_ro_compat = SWAP_LE32(EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER); create_uuid(sb->uuid); // TODO If we're called as mke3fs or mkfs.ext3, do a journal. //if (strchr(toys.which->name,'3')) // sb->feature_compat |= SWAP_LE32(EXT3_FEATURE_COMPAT_HAS_JOURNAL); } // Does this group contain a superblock backup (and group descriptor table)? static int is_sb_group(uint32_t group) { int i; // Superblock backups are on groups 0, 1, and powers of 3, 5, and 7. if(!group || group==1) return 1; for (i=3; i<9; i+=2) { int j = i; while (j<group) j*=i; if (j==group) return 1; } return 0; } // Number of blocks used in group by optional superblock/group list backup. static int group_superblock_overhead(uint32_t group) { int used; if (!is_sb_group(group)) return 0; // How many blocks does the group descriptor table take up? used = TT.groups * sizeof(struct ext2_group); used += TT.blocksize - 1; used /= TT.blocksize; // Plus the superblock itself. used++; // And a corner case. if (!group && TT.blocksize == 1024) used++; return used; } // Number of blocks used in group to store superblock/group/inode list static int group_overhead(uint32_t group) { // Return superblock backup overhead (if any), plus block/inode // allocation bitmaps, plus inode tables. return group_superblock_overhead(group) + 2 + get_inodespg(TT.inodespg) / (TT.blocksize/sizeof(struct ext2_inode)); } // In bitmap "array" set "len" bits starting at position "start" (from 0). static void bits_set(char *array, int start, int len) { while(len) { if ((start&7) || len<8) { array[start/8]|=(1<<(start&7)); start++; len--; } else { array[start/8]=255; start+=8; len-=8; } } } // Seek past len bytes (to maintain sparse file), or write zeroes if output // not seekable static void put_zeroes(int len) { if(-1 == lseek(TT.fsfd, len, SEEK_SET)) { memset(toybuf, 0, sizeof(toybuf)); while (len) { int out = len > sizeof(toybuf) ? sizeof(toybuf) : len; xwrite(TT.fsfd, toybuf, out); len -= out; } } } // Fill out an inode structure from struct stat info in dirtree. static void fill_inode(struct ext2_inode *in, struct dirtree *that) { uint32_t fbu[15]; int temp; file_blocks_used(that->st.st_size, fbu); // If that inode needs data blocks allocated to it. if (that->st.st_size) { int i, group = TT.nextblock/TT.blockbits; // TODO: teach this about indirect blocks. for (i=0; i<15; i++) { // If we just jumped into a new group, skip group overhead blocks. while (group >= TT.nextgroup) TT.nextblock += group_overhead(TT.nextgroup++); } } // TODO : S_ISREG/DIR/CHR/BLK/FIFO/LNK/SOCK(m) in->mode = SWAP_LE32(that->st.st_mode); in->uid = SWAP_LE16(that->st.st_uid & 0xFFFF); in->uid_high = SWAP_LE16(that->st.st_uid >> 16); in->gid = SWAP_LE16(that->st.st_gid & 0xFFFF); in->gid_high = SWAP_LE16(that->st.st_gid >> 16); in->size = SWAP_LE32(that->st.st_size & 0xFFFFFFFF); // Contortions to make the compiler not generate a warning for x>>32 // when x is 32 bits. The optimizer should clean this up. if (sizeof(that->st.st_size) > 4) temp = 32; else temp = 0; if (temp) in->dir_acl = SWAP_LE32(that->st.st_size >> temp); in->atime = SWAP_LE32(that->st.st_atime); in->ctime = SWAP_LE32(that->st.st_ctime); in->mtime = SWAP_LE32(that->st.st_mtime); in->links_count = SWAP_LE16(that->st.st_nlink); in->blocks = SWAP_LE32(that->st.st_blocks); // in->faddr } // Works like an archiver. // The first argument is the name of the file to create. If it already // exists, that size will be used. void mke2fs_main(void) { int i, temp; off_t length; uint32_t usedblocks, usedinodes, dtiblk, dtbblk; struct dirtree *dti, *dtb; // Handle command line arguments. if (toys.optargs[1]) { sscanf(toys.optargs[1], "%u", &TT.blocks); temp = O_RDWR|O_CREAT; } else temp = O_RDWR; if (!TT.reserved_percent) TT.reserved_percent = 5; // TODO: Check if filesystem is mounted here // For mke?fs, open file. For gene?fs, create file. TT.fsfd = xcreate(*toys.optargs, temp, 0777); // Determine appropriate block size and block count from file length. // (If no length, default to 4k. They can override it on the cmdline.) length = fdlength(TT.fsfd); if (!TT.blocksize) TT.blocksize = (length && length < 1<<29) ? 1024 : 4096; TT.blockbits = 8*TT.blocksize; if (!TT.blocks) TT.blocks = length/TT.blocksize; // Collect gene2fs list or lost+found, calculate requirements. if (TT.gendir) { strncpy(toybuf, TT.gendir, sizeof(toybuf)); dti = dirtree_read(toybuf, NULL, NULL); } else { dti = xzalloc(sizeof(struct dirtree)+11); strcpy(dti->name, "lost+found"); dti->st.st_mode = S_IFDIR|0755; dti->st.st_ctime = dti->st.st_mtime = time(NULL); } // Add root directory inode. This is iterated through for when finding // blocks, but not when finding inodes. The tree's parent pointers don't // point back into this. dtb = xzalloc(sizeof(struct dirtree)+1); dtb->st.st_mode = S_IFDIR|0755; dtb->st.st_ctime = dtb->st.st_mtime = time(NULL); dtb->child = dti; // Figure out how much space is used by preset files length = check_treesize(dtb, &(dtb->st.st_size)); check_treelinks(dtb); // Figure out how many total inodes we need. if (!TT.inodes) { if (!TT.bytes_per_inode) TT.bytes_per_inode = 8192; TT.inodes = (TT.blocks * (uint64_t)TT.blocksize) / TT.bytes_per_inode; } // If we're generating a filesystem and have no idea how many blocks it // needs, start with a minimal guess, find the overhead of that many // groups, and loop until this is enough groups to store this many blocks. if (!TT.blocks) TT.groups = (TT.treeblocks/TT.blockbits)+1; else TT.groups = div_round_up(TT.blocks, TT.blockbits); for (;;) { temp = TT.treeblocks; for (i = 0; i<TT.groups; i++) temp += group_overhead(i); if (TT.blocks) { if (TT.blocks < temp) error_exit("Not enough space.\n"); break; } if (temp <= TT.groups * TT.blockbits) { TT.blocks = temp; break; } TT.groups++; } TT.freeblocks = TT.blocks - temp; // Now we know all the TT data, initialize superblock structure. init_superblock(&TT.sb); // Start writing. Skip the first 1k to avoid the boot sector (if any). put_zeroes(1024); // Loop through block groups, write out each one. dtiblk = dtbblk = usedblocks = usedinodes = 0; for (i=0; i<TT.groups; i++) { struct ext2_inode *in = (struct ext2_inode *)toybuf; uint32_t start, itable, used, end; int j, slot; // Where does this group end? end = TT.blockbits; if ((i+1)*TT.blockbits > TT.blocks) end = TT.blocks & (TT.blockbits-1); // Blocks used by inode table itable = (TT.inodespg*sizeof(struct ext2_inode))/TT.blocksize; // If a superblock goes here, write it out. start = group_superblock_overhead(i); if (start) { struct ext2_group *bg = (struct ext2_group *)toybuf; int treeblocks = TT.treeblocks, treeinodes = TT.treeinodes; TT.sb.block_group_nr = SWAP_LE16(i); // Write superblock and pad it up to block size xwrite(TT.fsfd, &TT.sb, sizeof(struct ext2_superblock)); temp = TT.blocksize - sizeof(struct ext2_superblock); if (!i && TT.blocksize > 1024) temp -= 1024; memset(toybuf, 0, TT.blocksize); xwrite(TT.fsfd, toybuf, temp); // Loop through groups to write group descriptor table. for(j=0; j<TT.groups; j++) { // Figure out what sector this group starts in. used = group_superblock_overhead(j); // Find next array slot in this block (flush block if full). slot = j % (TT.blocksize/sizeof(struct ext2_group)); if (!slot) { if (j) xwrite(TT.fsfd, bg, TT.blocksize); memset(bg, 0, TT.blocksize); } // How many free inodes in this group? temp = TT.inodespg; if (!i) temp -= INODES_RESERVED; if (temp > treeinodes) { treeinodes -= temp; temp = 0; } else { temp -= treeinodes; treeinodes = 0; } bg[slot].free_inodes_count = SWAP_LE16(temp); // How many free blocks in this group? temp = TT.inodespg/(TT.blocksize/sizeof(struct ext2_inode)) + 2; temp = end-used-temp; if (temp > treeblocks) { treeblocks -= temp; temp = 0; } else { temp -= treeblocks; treeblocks = 0; } bg[slot].free_blocks_count = SWAP_LE32(temp); // Fill out rest of group structure used += j*TT.blockbits; bg[slot].block_bitmap = SWAP_LE32(used++); bg[slot].inode_bitmap = SWAP_LE32(used++); bg[slot].inode_table = SWAP_LE32(used); bg[slot].used_dirs_count = 0; // (TODO) } xwrite(TT.fsfd, bg, TT.blocksize); } // Now write out stuff that every block group has. // Write block usage bitmap start += 2 + itable; memset(toybuf, 0, TT.blocksize); bits_set(toybuf, 0, start); bits_set(toybuf, end, TT.blockbits-end); temp = TT.treeblocks - usedblocks; if (temp) { if (end-start > temp) temp = end-start; bits_set(toybuf, start, temp); } xwrite(TT.fsfd, toybuf, TT.blocksize); // Write inode bitmap memset(toybuf, 0, TT.blocksize); j = 0; if (!i) bits_set(toybuf, 0, j = INODES_RESERVED); bits_set(toybuf, TT.inodespg, slot = TT.blockbits-TT.inodespg); temp = TT.treeinodes - usedinodes; if (temp) { if (slot-j > temp) temp = slot-j; bits_set(toybuf, j, temp); } xwrite(TT.fsfd, toybuf, TT.blocksize); // Write inode table for this group (TODO) for (j = 0; j<TT.inodespg; j++) { slot = j % (TT.blocksize/sizeof(struct ext2_inode)); if (!slot) { if (j) xwrite(TT.fsfd, in, TT.blocksize); memset(in, 0, TT.blocksize); } if (!i && j<INODES_RESERVED) { // Write root inode if (j == 2) fill_inode(in+slot, dtb); } else if (dti) { fill_inode(in+slot, dti); dti = treenext(dti); } } xwrite(TT.fsfd, in, TT.blocksize); while (dtb) { // TODO write index data block // TODO write root directory data block // TODO write directory data block // TODO write file data block put_zeroes(TT.blocksize); start++; if (start == end) break; } // Write data blocks (TODO) put_zeroes((end-start) * TT.blocksize); } }