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 000000000000..bbfc86259272
--- /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
+};