/* * Mach Operating System * Copyright (c) 1991,1990 Carnegie Mellon University * All Rights Reserved. * * Permission to use, copy, modify and distribute this software and its * documentation is hereby granted, provided that both the copyright * notice and this permission notice appear in all copies of the * software, derivative works or modified versions, and any portions * thereof, and that both notices appear in supporting documentation. * * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. * * Carnegie Mellon requests users of this software to return to * * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU * School of Computer Science * Carnegie Mellon University * Pittsburgh PA 15213-3890 * * any improvements or extensions that they make and grant Carnegie Mellon * the rights to redistribute these changes. */ /* * Stand-alone file reading package. */ #include #include #include #include #include "file_io.h" #include "ffs_compat.h" void ext2_close_file(); /* forward */ /* * Free file buffers, but don't close file. */ static void free_file_buffers(fp) register struct file *fp; { register int level; /* * Free the indirect blocks */ for (level = 0; level < NIADDR; level++) { if (fp->f_blk[level] != 0) { (void) vm_deallocate(mach_task_self(), fp->f_blk[level], fp->f_blksize[level]); fp->f_blk[level] = 0; } fp->f_blkno[level] = -1; } /* * Free the data block */ if (fp->f_buf != 0) { (void) vm_deallocate(mach_task_self(), fp->f_buf, fp->f_buf_size); fp->f_buf = 0; } fp->f_buf_blkno = -1; } /* * Read a new inode into a file structure. */ static int read_inode(inumber, fp) ino_t inumber; register struct file *fp; { vm_offset_t buf; mach_msg_type_number_t buf_size; register struct ext2_super_block *fs; daddr_t disk_block; kern_return_t rc; fs = fp->f_fs; disk_block = ino2blk(fs, fp->f_gd, inumber); rc = device_read(fp->f_dev, 0, (recnum_t) fsbtodb(fp->f_fs, disk_block), (int) EXT2_BLOCK_SIZE(fs), (char **)&buf, &buf_size); if (rc != KERN_SUCCESS) return (rc); { register struct ext2_inode *dp; dp = (struct ext2_inode *)buf; dp += itoo(fs, inumber); fp->i_ic = *dp; fp->f_size = dp->i_size; } (void) vm_deallocate(mach_task_self(), buf, buf_size); /* * Clear out the old buffers */ free_file_buffers(fp); return (0); } /* * Given an offset in a file, find the disk block number that * contains that block. */ static int block_map(fp, file_block, disk_block_p) struct file *fp; daddr_t file_block; daddr_t *disk_block_p; /* out */ { int level; int idx; daddr_t ind_block_num; kern_return_t rc; vm_offset_t olddata[NIADDR+1]; vm_size_t oldsize[NIADDR+1]; /* * Index structure of an inode: * * i_db[0..NDADDR-1] hold block numbers for blocks * 0..NDADDR-1 * * i_ib[0] index block 0 is the single indirect * block * holds block numbers for blocks * NDADDR .. NDADDR + NINDIR(fs)-1 * * i_ib[1] index block 1 is the double indirect * block * holds block numbers for INDEX blocks * for blocks * NDADDR + NINDIR(fs) .. * NDADDR + NINDIR(fs) + NINDIR(fs)**2 - 1 * * i_ib[2] index block 2 is the triple indirect * block * holds block numbers for double-indirect * blocks for blocks * NDADDR + NINDIR(fs) + NINDIR(fs)**2 .. * NDADDR + NINDIR(fs) + NINDIR(fs)**2 * + NINDIR(fs)**3 - 1 */ mutex_lock(&fp->f_lock); if (file_block < NDADDR) { /* Direct block. */ *disk_block_p = fp->i_ic.i_block[file_block]; mutex_unlock(&fp->f_lock); return (0); } file_block -= NDADDR; /* * nindir[0] = NINDIR * nindir[1] = NINDIR**2 * nindir[2] = NINDIR**3 * etc */ for (level = 0; level < NIADDR; level++) { if (file_block < fp->f_nindir[level]) break; file_block -= fp->f_nindir[level]; } if (level == NIADDR) { /* Block number too high */ mutex_unlock(&fp->f_lock); return (FS_NOT_IN_FILE); } ind_block_num = fp->i_ic.i_block[level + NDADDR]; /* * Initialize array of blocks to free. */ for (idx = 0; idx < NIADDR; idx++) oldsize[idx] = 0; for (; level >= 0; level--) { vm_offset_t data; mach_msg_type_number_t size; if (ind_block_num == 0) break; if (fp->f_blkno[level] == ind_block_num) { /* * Cache hit. Just pick up the data. */ data = fp->f_blk[level]; } else { /* * Drop our lock while doing the read. * (The f_dev and f_fs fields don`t change.) */ mutex_unlock(&fp->f_lock); rc = device_read(fp->f_dev, 0, (recnum_t) fsbtodb(fp->f_fs, ind_block_num), EXT2_BLOCK_SIZE(fp->f_fs), (char **)&data, &size); if (rc != KERN_SUCCESS) return (rc); /* * See if we can cache the data. Need a write lock to * do this. While we hold the write lock, we can`t do * *anything* which might block for memory. Otherwise * a non-privileged thread might deadlock with the * privileged threads. We can`t block while taking the * write lock. Otherwise a non-privileged thread * blocked in the vm_deallocate (while holding a read * lock) will block a privileged thread. For the same * reason, we can`t take a read lock and then use * lock_read_to_write. */ mutex_lock(&fp->f_lock); olddata[level] = fp->f_blk[level]; oldsize[level] = fp->f_blksize[level]; fp->f_blkno[level] = ind_block_num; fp->f_blk[level] = data; fp->f_blksize[level] = size; /* * Return to holding a read lock, and * dispose of old data. */ } if (level > 0) { idx = file_block / fp->f_nindir[level-1]; file_block %= fp->f_nindir[level-1]; } else idx = file_block; ind_block_num = ((daddr_t *)data)[idx]; } mutex_unlock(&fp->f_lock); /* * After unlocking the file, free any blocks that * we need to free. */ for (idx = 0; idx < NIADDR; idx++) if (oldsize[idx] != 0) (void) vm_deallocate(mach_task_self(), olddata[idx], oldsize[idx]); *disk_block_p = ind_block_num; return (0); } /* * Read a portion of a file into an internal buffer. Return * the location in the buffer and the amount in the buffer. */ static int buf_read_file(fp, offset, buf_p, size_p) register struct file *fp; vm_offset_t offset; vm_offset_t *buf_p; /* out */ vm_size_t *size_p; /* out */ { register struct ext2_super_block *fs; vm_offset_t off; register daddr_t file_block; daddr_t disk_block; int rc; vm_offset_t block_size; if (offset >= fp->i_ic.i_size) return (FS_NOT_IN_FILE); fs = fp->f_fs; off = blkoff(fs, offset); file_block = lblkno(fs, offset); block_size = blksize(fs, fp, file_block); if (file_block != fp->f_buf_blkno) { rc = block_map(fp, file_block, &disk_block); if (rc != 0) return (rc); if (fp->f_buf) (void)vm_deallocate(mach_task_self(), fp->f_buf, fp->f_buf_size); if (disk_block == 0) { (void)vm_allocate(mach_task_self(), &fp->f_buf, block_size, TRUE); fp->f_buf_size = block_size; } else { rc = device_read(fp->f_dev, 0, (recnum_t) fsbtodb(fs, disk_block), (int) block_size, (char **) &fp->f_buf, (mach_msg_type_number_t *)&fp->f_buf_size); } if (rc) return (rc); fp->f_buf_blkno = file_block; } /* * Return address of byte in buffer corresponding to * offset, and size of remainder of buffer after that * byte. */ *buf_p = fp->f_buf + off; *size_p = block_size - off; /* * But truncate buffer at end of file. */ if (*size_p > fp->i_ic.i_size - offset) *size_p = fp->i_ic.i_size - offset; return (0); } /* * Search a directory for a name and return its * i_number. */ static int search_directory(name, fp, inumber_p) char * name; register struct file *fp; ino_t *inumber_p; /* out */ { vm_offset_t buf; vm_size_t buf_size; vm_offset_t offset; struct ext2_dir_entry_2 *dp; int length; kern_return_t rc; char tmp_name[256]; length = strlen(name); offset = 0; while (offset < fp->i_ic.i_size) { rc = buf_read_file(fp, offset, &buf, &buf_size); if (rc != KERN_SUCCESS) return (rc); dp = (struct ext2_dir_entry_2 *)buf; if (dp->inode != 0) { strncpy (tmp_name, dp->name, dp->name_len); tmp_name[dp->name_len] = '\0'; if (dp->name_len == length && !strcmp(name, tmp_name)) { /* found entry */ *inumber_p = dp->inode; return (0); } } offset += dp->rec_len; } return (FS_NO_ENTRY); } static int read_fs(dev, fsp, gdp, gd_size_p) mach_port_t dev; struct ext2_super_block **fsp; struct ext2_group_desc **gdp; vm_size_t *gd_size_p; { register struct ext2_super_block *fs; vm_offset_t buf; vm_offset_t buf2; mach_msg_type_number_t buf_size; mach_msg_type_number_t buf2_size; int error; int gd_count; int gd_blocks; int gd_size; int gd_location; int gd_sector; /* * Read the super block */ error = device_read(dev, 0, (recnum_t) SBLOCK, SBSIZE, (char **) &buf, &buf_size); if (error) return (error); /* * Check the superblock */ fs = (struct ext2_super_block *)buf; if (fs->s_magic != EXT2_SUPER_MAGIC) { (void) vm_deallocate(mach_task_self(), buf, buf_size); return (FS_INVALID_FS); } *fsp = fs; /* * Compute the groups informations */ gd_count = (fs->s_blocks_count - fs->s_first_data_block + fs->s_blocks_per_group - 1) / fs->s_blocks_per_group; gd_blocks = (gd_count + EXT2_DESC_PER_BLOCK(fs) - 1) / EXT2_DESC_PER_BLOCK(fs); gd_size = gd_blocks * EXT2_BLOCK_SIZE(fs); gd_location = fs->s_first_data_block + 1; gd_sector = (gd_location * EXT2_BLOCK_SIZE(fs)) / DEV_BSIZE; /* * Read the groups descriptors */ error = device_read(dev, 0, (recnum_t) gd_sector, gd_size, (char **) &buf2, &buf2_size); if (error) { (void) vm_deallocate(mach_task_self(), buf, buf_size); return error; } *gdp = (struct ext2_group_desc *) buf2; *gd_size_p = gd_size; return 0; } static int mount_fs(fp) register struct file *fp; { register struct ext2_super_block *fs; int error; error = read_fs(fp->f_dev, &fp->f_fs, &fp->f_gd, &fp->f_gd_size); if (error) return (error); fs = fp->f_fs; /* * Calculate indirect block levels. */ { register int mult; register int level; mult = 1; for (level = 0; level < NIADDR; level++) { mult *= NINDIR(fs); fp->f_nindir[level] = mult; } } return (0); } static void unmount_fs(fp) register struct file *fp; { if (file_is_structured(fp)) { (void) vm_deallocate(mach_task_self(), (vm_offset_t) fp->f_fs, SBSIZE); (void) vm_deallocate(mach_task_self(), (vm_offset_t) fp->f_gd, fp->f_gd_size); fp->f_fs = 0; } } /* * Open a file. */ int ext2_open_file(master_device_port, path, fp) mach_port_t master_device_port; char * path; struct file *fp; { #define RETURN(code) { rc = (code); goto exit; } register char *cp, *component; register int c; /* char */ register int rc; ino_t inumber, parent_inumber; int nlinks = 0; char namebuf[MAXPATHLEN+1]; if (path == 0 || *path == '\0') { return FS_NO_ENTRY; } /* * Copy name into buffer to allow modifying it. */ strcpy(namebuf, path); /* * Look for '/dev/xxx' at start of path, for * root device. */ if (!strprefix(namebuf, "/dev/")) { printf("no device name\n"); return FS_NO_ENTRY; } cp = namebuf + 5; /* device */ component = cp; while ((c = *cp) != '\0' && c != '/') { cp++; } *cp = '\0'; bzero (fp, sizeof (struct file)); rc = device_open(master_device_port, D_READ|D_WRITE, component, &fp->f_dev); if (rc) return rc; if (c == 0) { fp->f_fs = 0; goto out_ok; } *cp = c; rc = mount_fs(fp); if (rc) return rc; inumber = (ino_t) ROOTINO; if ((rc = read_inode(inumber, fp)) != 0) { printf("can't read root inode\n"); goto exit; } while (*cp) { /* * Check that current node is a directory. */ if ((fp->i_ic.i_mode & IFMT) != IFDIR) RETURN (FS_NOT_DIRECTORY); /* * Remove extra separators */ while (*cp == '/') cp++; /* * Get next component of path name. */ component = cp; { register int len = 0; while ((c = *cp) != '\0' && c != '/') { if (len++ > MAXNAMLEN) RETURN (FS_NAME_TOO_LONG); if (c & 0200) RETURN (FS_INVALID_PARAMETER); cp++; } *cp = 0; } /* * Look up component in current directory. * Save directory inumber in case we find a * symbolic link. */ parent_inumber = inumber; rc = search_directory(component, fp, &inumber); if (rc) { printf("%s: not found\n", path); goto exit; } *cp = c; /* * Open next component. */ if ((rc = read_inode(inumber, fp)) != 0) goto exit; /* * Check for symbolic link. */ if ((fp->i_ic.i_mode & IFMT) == IFLNK) { int link_len = fp->i_ic.i_size; int len; len = strlen(cp) + 1; if (link_len + len >= MAXPATHLEN - 1) RETURN (FS_NAME_TOO_LONG); if (++nlinks > MAXSYMLINKS) RETURN (FS_SYMLINK_LOOP); memmove(&namebuf[link_len], cp, len); #ifdef IC_FASTLINK if (fp->i_ic.i_blocks == 0) { bcopy(fp->i_ic.i_block, namebuf, (unsigned) link_len); } else #endif /* IC_FASTLINK */ { /* * Read file for symbolic link */ vm_offset_t buf; mach_msg_type_number_t buf_size; daddr_t disk_block; register struct ext2_super_block *fs = fp->f_fs; (void) block_map(fp, (daddr_t)0, &disk_block); rc = device_read(fp->f_dev, 0, (recnum_t) fsbtodb(fs, disk_block), (int) blksize(fs, fp, 0), (char **) &buf, &buf_size); if (rc) goto exit; bcopy((char *)buf, namebuf, (unsigned)link_len); (void) vm_deallocate(mach_task_self(), buf, buf_size); } /* * If relative pathname, restart at parent directory. * If absolute pathname, restart at root. * If pathname begins '/dev//', * restart at root of that device. */ cp = namebuf; if (*cp != '/') { inumber = parent_inumber; } else if (!strprefix(cp, "/dev/")) { inumber = (ino_t)ROOTINO; } else { cp += 5; component = cp; while ((c = *cp) != '\0' && c != '/') { cp++; } *cp = '\0'; /* * Unmount current file system and free buffers. */ ext2_close_file(fp); /* * Open new root device. */ rc = device_open(master_device_port, D_READ, component, &fp->f_dev); if (rc) return (rc); if (c == 0) { fp->f_fs = 0; goto out_ok; } *cp = c; rc = mount_fs(fp); if (rc) return (rc); inumber = (ino_t)ROOTINO; } if ((rc = read_inode(inumber, fp)) != 0) goto exit; } } /* * Found terminal component. */ out_ok: mutex_init(&fp->f_lock); return 0; /* * At error exit, close file to free storage. */ exit: ext2_close_file(fp); return rc; } /* * Close file - free all storage used. */ void ext2_close_file(fp) register struct file *fp; { register int i; /* * Free the disk super-block. */ unmount_fs(fp); /* * Free the inode and data buffers. */ free_file_buffers(fp); } int ext2_file_is_directory(struct file *fp) { return (fp->i_ic.i_mode & IFMT) == IFDIR; } int ext2_file_is_regular(struct file *fp) { return (fp->i_ic.i_mode & IFMT) == IFREG; } /* * Copy a portion of a file into kernel memory. * Cross block boundaries when necessary. */ int ext2_read_file(fp, offset, start, size, resid) register struct file *fp; vm_offset_t offset; vm_offset_t start; vm_size_t size; vm_size_t *resid; /* out */ { int rc; register vm_size_t csize; vm_offset_t buf; vm_size_t buf_size; while (size != 0) { rc = buf_read_file(fp, offset, &buf, &buf_size); if (rc) return (rc); csize = size; if (csize > buf_size) csize = buf_size; if (csize == 0) break; bcopy((char *)buf, (char *)start, csize); offset += csize; start += csize; size -= csize; } if (resid) *resid = size; return (0); } /* simple utility: only works for 2^n */ static int log2(n) register unsigned int n; { register int i = 0; while ((n & 1) == 0) { i++; n >>= 1; } return i; } /* * Make an empty file_direct for a device. */ int ext2_open_file_direct(dev, fdp, is_structured) mach_port_t dev; register struct file_direct *fdp; boolean_t is_structured; { struct ext2_super_block *fs; struct ext2_group_desc *gd; vm_size_t gd_size; int rc; if (!is_structured) { fdp->fd_dev = dev; fdp->fd_blocks = (daddr_t *) 0; fdp->fd_bsize = vm_page_size; fdp->fd_bshift = log2(vm_page_size); fdp->fd_fsbtodb = 0; /* later */ fdp->fd_size = 0; /* later */ return 0; } rc = read_fs(dev, &fs, &gd, &gd_size); if (rc) return rc; fdp->fd_dev = dev; fdp->fd_blocks = (daddr_t *) 0; fdp->fd_size = 0; fdp->fd_bsize = EXT2_BLOCK_SIZE(fs); fdp->fd_bshift = log2(fdp->fd_bsize); fdp->fd_fsbtodb = log2(fdp->fd_bsize / DEV_BSIZE); (void) vm_deallocate(mach_task_self(), (vm_offset_t) fs, SBSIZE); (void) vm_deallocate(mach_task_self(), (vm_offset_t) gd, gd_size); return 0; } /* * Add blocks from a file to a file_direct. */ int ext2_add_file_direct(fdp, fp) register struct file_direct *fdp; register struct file *fp; { register struct ext2_super_block *fs; long num_blocks, i; vm_offset_t buffer; vm_size_t size; int rc; /* the file must be on the same device */ if (fdp->fd_dev != fp->f_dev) return FS_INVALID_FS; if (!file_is_structured(fp)) { int result[DEV_GET_SIZE_COUNT]; natural_t count; count = DEV_GET_SIZE_COUNT; rc = device_get_status( fdp->fd_dev, DEV_GET_SIZE, result, &count); if (rc) return rc; fdp->fd_size = result[DEV_GET_SIZE_DEVICE_SIZE] >> fdp->fd_bshift; fdp->fd_fsbtodb = log2(fdp->fd_bsize/result[DEV_GET_SIZE_RECORD_SIZE]); return 0; } /* it must hold a file system */ fs = fp->f_fs; /* if (fdp->fd_bsize != fs->fs_bsize || fdp->fd_fsbtodb != fs->fs_fsbtodb) */ if (fdp->fd_bsize != EXT2_BLOCK_SIZE(fs)) return FS_INVALID_FS; /* calculate number of blocks in the file, ignoring fragments */ num_blocks = lblkno(fs, fp->i_ic.i_size); /* allocate memory for a bigger array */ size = (num_blocks + fdp->fd_size) * sizeof(daddr_t); rc = vm_allocate(mach_task_self(), &buffer, size, TRUE); if (rc != KERN_SUCCESS) return rc; /* lookup new block addresses */ for (i = 0; i < num_blocks; i++) { daddr_t disk_block; rc = block_map(fp, (daddr_t) i, &disk_block); if (rc != 0) { (void) vm_deallocate(mach_task_self(), buffer, size); return rc; } ((daddr_t *) buffer)[fdp->fd_size + i] = disk_block; } /* copy old addresses and install the new array */ if (fdp->fd_blocks != 0) { bcopy((char *) fdp->fd_blocks, (char *) buffer, fdp->fd_size * sizeof(daddr_t)); (void) vm_deallocate(mach_task_self(), (vm_offset_t) fdp->fd_blocks, (vm_size_t) (fdp->fd_size * sizeof(daddr_t))); } fdp->fd_blocks = (daddr_t *) buffer; fdp->fd_size += num_blocks; /* deallocate cached blocks */ free_file_buffers(fp); return 0; } int ext2_remove_file_direct(fdp) struct file_direct *fdp; { if (fdp->fd_blocks) (void) vm_deallocate(mach_task_self(), (vm_offset_t) fdp->fd_blocks, (vm_size_t) (fdp->fd_size * sizeof(daddr_t))); fdp->fd_blocks = 0; /* sanity */ /* xxx should lose a ref to fdp->fd_dev here (and elsewhere) xxx */ }