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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /fs/adfs/dir_f.c | |
download | kernel_samsung_smdk4412-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.zip kernel_samsung_smdk4412-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz kernel_samsung_smdk4412-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.bz2 |
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'fs/adfs/dir_f.c')
-rw-r--r-- | fs/adfs/dir_f.c | 460 |
1 files changed, 460 insertions, 0 deletions
diff --git a/fs/adfs/dir_f.c b/fs/adfs/dir_f.c new file mode 100644 index 0000000..bbfc862 --- /dev/null +++ b/fs/adfs/dir_f.c @@ -0,0 +1,460 @@ +/* + * linux/fs/adfs/dir_f.c + * + * Copyright (C) 1997-1999 Russell King + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * E and F format directory handling + */ +#include <linux/errno.h> +#include <linux/fs.h> +#include <linux/adfs_fs.h> +#include <linux/time.h> +#include <linux/stat.h> +#include <linux/spinlock.h> +#include <linux/buffer_head.h> +#include <linux/string.h> + +#include "adfs.h" +#include "dir_f.h" + +static void adfs_f_free(struct adfs_dir *dir); + +/* + * Read an (unaligned) value of length 1..4 bytes + */ +static inline unsigned int adfs_readval(unsigned char *p, int len) +{ + unsigned int val = 0; + + switch (len) { + case 4: val |= p[3] << 24; + case 3: val |= p[2] << 16; + case 2: val |= p[1] << 8; + default: val |= p[0]; + } + return val; +} + +static inline void adfs_writeval(unsigned char *p, int len, unsigned int val) +{ + switch (len) { + case 4: p[3] = val >> 24; + case 3: p[2] = val >> 16; + case 2: p[1] = val >> 8; + default: p[0] = val; + } +} + +static inline int adfs_readname(char *buf, char *ptr, int maxlen) +{ + char *old_buf = buf; + + while (*ptr >= ' ' && maxlen--) { + if (*ptr == '/') + *buf++ = '.'; + else + *buf++ = *ptr; + ptr++; + } + *buf = '\0'; + + return buf - old_buf; +} + +#define ror13(v) ((v >> 13) | (v << 19)) + +#define dir_u8(idx) \ + ({ int _buf = idx >> blocksize_bits; \ + int _off = idx - (_buf << blocksize_bits);\ + *(u8 *)(bh[_buf]->b_data + _off); \ + }) + +#define dir_u32(idx) \ + ({ int _buf = idx >> blocksize_bits; \ + int _off = idx - (_buf << blocksize_bits);\ + *(__le32 *)(bh[_buf]->b_data + _off); \ + }) + +#define bufoff(_bh,_idx) \ + ({ int _buf = _idx >> blocksize_bits; \ + int _off = _idx - (_buf << blocksize_bits);\ + (u8 *)(_bh[_buf]->b_data + _off); \ + }) + +/* + * There are some algorithms that are nice in + * assembler, but a bitch in C... This is one + * of them. + */ +static u8 +adfs_dir_checkbyte(const struct adfs_dir *dir) +{ + struct buffer_head * const *bh = dir->bh; + const int blocksize_bits = dir->sb->s_blocksize_bits; + union { __le32 *ptr32; u8 *ptr8; } ptr, end; + u32 dircheck = 0; + int last = 5 - 26; + int i = 0; + + /* + * Accumulate each word up to the last whole + * word of the last directory entry. This + * can spread across several buffer heads. + */ + do { + last += 26; + do { + dircheck = le32_to_cpu(dir_u32(i)) ^ ror13(dircheck); + + i += sizeof(u32); + } while (i < (last & ~3)); + } while (dir_u8(last) != 0); + + /* + * Accumulate the last few bytes. These + * bytes will be within the same bh. + */ + if (i != last) { + ptr.ptr8 = bufoff(bh, i); + end.ptr8 = ptr.ptr8 + last - i; + + do + dircheck = *ptr.ptr8++ ^ ror13(dircheck); + while (ptr.ptr8 < end.ptr8); + } + + /* + * The directory tail is in the final bh + * Note that contary to the RISC OS PRMs, + * the first few bytes are NOT included + * in the check. All bytes are in the + * same bh. + */ + ptr.ptr8 = bufoff(bh, 2008); + end.ptr8 = ptr.ptr8 + 36; + + do { + __le32 v = *ptr.ptr32++; + dircheck = le32_to_cpu(v) ^ ror13(dircheck); + } while (ptr.ptr32 < end.ptr32); + + return (dircheck ^ (dircheck >> 8) ^ (dircheck >> 16) ^ (dircheck >> 24)) & 0xff; +} + +/* + * Read and check that a directory is valid + */ +static int +adfs_dir_read(struct super_block *sb, unsigned long object_id, + unsigned int size, struct adfs_dir *dir) +{ + const unsigned int blocksize_bits = sb->s_blocksize_bits; + int blk = 0; + + /* + * Directories which are not a multiple of 2048 bytes + * are considered bad v2 [3.6] + */ + if (size & 2047) + goto bad_dir; + + size >>= blocksize_bits; + + dir->nr_buffers = 0; + dir->sb = sb; + + for (blk = 0; blk < size; blk++) { + int phys; + + phys = __adfs_block_map(sb, object_id, blk); + if (!phys) { + adfs_error(sb, "dir object %lX has a hole at offset %d", + object_id, blk); + goto release_buffers; + } + + dir->bh[blk] = sb_bread(sb, phys); + if (!dir->bh[blk]) + goto release_buffers; + } + + memcpy(&dir->dirhead, bufoff(dir->bh, 0), sizeof(dir->dirhead)); + memcpy(&dir->dirtail, bufoff(dir->bh, 2007), sizeof(dir->dirtail)); + + if (dir->dirhead.startmasseq != dir->dirtail.new.endmasseq || + memcmp(&dir->dirhead.startname, &dir->dirtail.new.endname, 4)) + goto bad_dir; + + if (memcmp(&dir->dirhead.startname, "Nick", 4) && + memcmp(&dir->dirhead.startname, "Hugo", 4)) + goto bad_dir; + + if (adfs_dir_checkbyte(dir) != dir->dirtail.new.dircheckbyte) + goto bad_dir; + + dir->nr_buffers = blk; + + return 0; + +bad_dir: + adfs_error(sb, "corrupted directory fragment %lX", + object_id); +release_buffers: + for (blk -= 1; blk >= 0; blk -= 1) + brelse(dir->bh[blk]); + + dir->sb = NULL; + + return -EIO; +} + +/* + * convert a disk-based directory entry to a Linux ADFS directory entry + */ +static inline void +adfs_dir2obj(struct object_info *obj, struct adfs_direntry *de) +{ + obj->name_len = adfs_readname(obj->name, de->dirobname, ADFS_F_NAME_LEN); + obj->file_id = adfs_readval(de->dirinddiscadd, 3); + obj->loadaddr = adfs_readval(de->dirload, 4); + obj->execaddr = adfs_readval(de->direxec, 4); + obj->size = adfs_readval(de->dirlen, 4); + obj->attr = de->newdiratts; +} + +/* + * convert a Linux ADFS directory entry to a disk-based directory entry + */ +static inline void +adfs_obj2dir(struct adfs_direntry *de, struct object_info *obj) +{ + adfs_writeval(de->dirinddiscadd, 3, obj->file_id); + adfs_writeval(de->dirload, 4, obj->loadaddr); + adfs_writeval(de->direxec, 4, obj->execaddr); + adfs_writeval(de->dirlen, 4, obj->size); + de->newdiratts = obj->attr; +} + +/* + * get a directory entry. Note that the caller is responsible + * for holding the relevant locks. + */ +static int +__adfs_dir_get(struct adfs_dir *dir, int pos, struct object_info *obj) +{ + struct super_block *sb = dir->sb; + struct adfs_direntry de; + int thissize, buffer, offset; + + buffer = pos >> sb->s_blocksize_bits; + + if (buffer > dir->nr_buffers) + return -EINVAL; + + offset = pos & (sb->s_blocksize - 1); + thissize = sb->s_blocksize - offset; + if (thissize > 26) + thissize = 26; + + memcpy(&de, dir->bh[buffer]->b_data + offset, thissize); + if (thissize != 26) + memcpy(((char *)&de) + thissize, dir->bh[buffer + 1]->b_data, + 26 - thissize); + + if (!de.dirobname[0]) + return -ENOENT; + + adfs_dir2obj(obj, &de); + + return 0; +} + +static int +__adfs_dir_put(struct adfs_dir *dir, int pos, struct object_info *obj) +{ + struct super_block *sb = dir->sb; + struct adfs_direntry de; + int thissize, buffer, offset; + + buffer = pos >> sb->s_blocksize_bits; + + if (buffer > dir->nr_buffers) + return -EINVAL; + + offset = pos & (sb->s_blocksize - 1); + thissize = sb->s_blocksize - offset; + if (thissize > 26) + thissize = 26; + + /* + * Get the entry in total + */ + memcpy(&de, dir->bh[buffer]->b_data + offset, thissize); + if (thissize != 26) + memcpy(((char *)&de) + thissize, dir->bh[buffer + 1]->b_data, + 26 - thissize); + + /* + * update it + */ + adfs_obj2dir(&de, obj); + + /* + * Put the new entry back + */ + memcpy(dir->bh[buffer]->b_data + offset, &de, thissize); + if (thissize != 26) + memcpy(dir->bh[buffer + 1]->b_data, ((char *)&de) + thissize, + 26 - thissize); + + return 0; +} + +/* + * the caller is responsible for holding the necessary + * locks. + */ +static int +adfs_dir_find_entry(struct adfs_dir *dir, unsigned long object_id) +{ + int pos, ret; + + ret = -ENOENT; + + for (pos = 5; pos < ADFS_NUM_DIR_ENTRIES * 26 + 5; pos += 26) { + struct object_info obj; + + if (!__adfs_dir_get(dir, pos, &obj)) + break; + + if (obj.file_id == object_id) { + ret = pos; + break; + } + } + + return ret; +} + +static int +adfs_f_read(struct super_block *sb, unsigned int id, unsigned int sz, struct adfs_dir *dir) +{ + int ret; + + if (sz != ADFS_NEWDIR_SIZE) + return -EIO; + + ret = adfs_dir_read(sb, id, sz, dir); + if (ret) + adfs_error(sb, "unable to read directory"); + else + dir->parent_id = adfs_readval(dir->dirtail.new.dirparent, 3); + + return ret; +} + +static int +adfs_f_setpos(struct adfs_dir *dir, unsigned int fpos) +{ + if (fpos >= ADFS_NUM_DIR_ENTRIES) + return -ENOENT; + + dir->pos = 5 + fpos * 26; + return 0; +} + +static int +adfs_f_getnext(struct adfs_dir *dir, struct object_info *obj) +{ + unsigned int ret; + + ret = __adfs_dir_get(dir, dir->pos, obj); + if (ret == 0) + dir->pos += 26; + + return ret; +} + +static int +adfs_f_update(struct adfs_dir *dir, struct object_info *obj) +{ + struct super_block *sb = dir->sb; + int ret, i; + + ret = adfs_dir_find_entry(dir, obj->file_id); + if (ret < 0) { + adfs_error(dir->sb, "unable to locate entry to update"); + goto out; + } + + __adfs_dir_put(dir, ret, obj); + + /* + * Increment directory sequence number + */ + dir->bh[0]->b_data[0] += 1; + dir->bh[dir->nr_buffers - 1]->b_data[sb->s_blocksize - 6] += 1; + + ret = adfs_dir_checkbyte(dir); + /* + * Update directory check byte + */ + dir->bh[dir->nr_buffers - 1]->b_data[sb->s_blocksize - 1] = ret; + +#if 1 + { + const unsigned int blocksize_bits = sb->s_blocksize_bits; + + memcpy(&dir->dirhead, bufoff(dir->bh, 0), sizeof(dir->dirhead)); + memcpy(&dir->dirtail, bufoff(dir->bh, 2007), sizeof(dir->dirtail)); + + if (dir->dirhead.startmasseq != dir->dirtail.new.endmasseq || + memcmp(&dir->dirhead.startname, &dir->dirtail.new.endname, 4)) + goto bad_dir; + + if (memcmp(&dir->dirhead.startname, "Nick", 4) && + memcmp(&dir->dirhead.startname, "Hugo", 4)) + goto bad_dir; + + if (adfs_dir_checkbyte(dir) != dir->dirtail.new.dircheckbyte) + goto bad_dir; + } +#endif + for (i = dir->nr_buffers - 1; i >= 0; i--) + mark_buffer_dirty(dir->bh[i]); + + ret = 0; +out: + return ret; +#if 1 +bad_dir: + adfs_error(dir->sb, "whoops! I broke a directory!"); + return -EIO; +#endif +} + +static void +adfs_f_free(struct adfs_dir *dir) +{ + int i; + + for (i = dir->nr_buffers - 1; i >= 0; i--) { + brelse(dir->bh[i]); + dir->bh[i] = NULL; + } + + dir->nr_buffers = 0; + dir->sb = NULL; +} + +struct adfs_dir_ops adfs_f_dir_ops = { + .read = adfs_f_read, + .setpos = adfs_f_setpos, + .getnext = adfs_f_getnext, + .update = adfs_f_update, + .free = adfs_f_free +}; |