--- /dev/null
+/*
+ * 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/buffer_head.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 ((unsigned char)*ptr >= ' ' && maxlen--) {
+ if (*ptr == '/')
+ *buf++ = '.';
+ else
+ *buf++ = *ptr;
+ ptr++;
+ }
+
+ 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 adfs_dir *dir, 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;
+ obj->filetype = -1;
+
+ /*
+ * object is a file and is filetyped and timestamped?
+ * RISC OS 12-bit filetype is stored in load_address[19:8]
+ */
+ if ((0 == (obj->attr & ADFS_NDA_DIRECTORY)) &&
+ (0xfff00000 == (0xfff00000 & obj->loadaddr))) {
+ obj->filetype = (__u16) ((0x000fff00 & obj->loadaddr) >> 8);
+
+ /* optionally append the ,xyz hex filetype suffix */
+ if (ADFS_SB(dir->sb)->s_ftsuffix)
+ obj->name_len +=
+ append_filetype_suffix(
+ &obj->name[obj->name_len],
+ obj->filetype);
+ }
+}
+
+/*
+ * 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(dir, 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 int
+adfs_f_sync(struct adfs_dir *dir)
+{
+ int err = 0;
+ int i;
+
+ for (i = dir->nr_buffers - 1; i >= 0; i--) {
+ struct buffer_head *bh = dir->bh[i];
+ sync_dirty_buffer(bh);
+ if (buffer_req(bh) && !buffer_uptodate(bh))
+ err = -EIO;
+ }
+
+ return err;
+}
+
+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,
+ .sync = adfs_f_sync,
+ .free = adfs_f_free
+};
Code Review / kvmfornfv.git / blobdiff