linux/fs/adfs/dir_fplus.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 *  linux/fs/adfs/dir_fplus.c
 *
 *  Copyright (C) 1997-1999 Russell King
 */
#include <linux/slab.h>
#include "adfs.h"
#include "dir_fplus.h"

static int
adfs_fplus_read(struct super_block *sb, unsigned int id, unsigned int sz, struct adfs_dir *dir)
{
	struct adfs_bigdirheader *h;
	struct adfs_bigdirtail *t;
	unsigned long block;
	unsigned int blk, size;
	int ret = -EIO;

	block = __adfs_block_map(sb, id, 0);
	if (!block) {
		adfs_error(sb, "dir object %X has a hole at offset 0", id);
		goto out;
	}

	dir->bhs[0] = sb_bread(sb, block);
	if (!dir->bhs[0])
		goto out;
	dir->nr_buffers += 1;

	h = (struct adfs_bigdirheader *)dir->bhs[0]->b_data;
	size = le32_to_cpu(h->bigdirsize);
	if (size != sz) {
		adfs_msg(sb, KERN_WARNING,
			 "directory header size %X does not match directory size %X",
			 size, sz);
	}

	if (h->bigdirversion[0] != 0 || h->bigdirversion[1] != 0 ||
	    h->bigdirversion[2] != 0 || size & 2047 ||
	    h->bigdirstartname != cpu_to_le32(BIGDIRSTARTNAME)) {
		adfs_error(sb, "dir %06x has malformed header", id);
		goto out;
	}

	size >>= sb->s_blocksize_bits;
	if (size > ARRAY_SIZE(dir->bh)) {
		/* this directory is too big for fixed bh set, must allocate */
		struct buffer_head **bhs =
			kcalloc(size, sizeof(struct buffer_head *),
				GFP_KERNEL);
		if (!bhs) {
			adfs_msg(sb, KERN_ERR,
				 "not enough memory for dir object %X (%d blocks)",
				 id, size);
			ret = -ENOMEM;
			goto out;
		}
		dir->bhs = bhs;
		/* copy over the pointer to the block that we've already read */
		dir->bhs[0] = dir->bh[0];
	}

	for (blk = 1; blk < size; blk++) {
		block = __adfs_block_map(sb, id, blk);
		if (!block) {
			adfs_error(sb, "dir object %X has a hole at offset %d", id, blk);
			goto out;
		}

		dir->bhs[blk] = sb_bread(sb, block);
		if (!dir->bhs[blk]) {
			adfs_error(sb,	"dir object %x failed read for offset %d, mapped block %lX",
				   id, blk, block);
			goto out;
		}

		dir->nr_buffers += 1;
	}

	t = (struct adfs_bigdirtail *)
		(dir->bhs[size - 1]->b_data + (sb->s_blocksize - 8));

	if (t->bigdirendname != cpu_to_le32(BIGDIRENDNAME) ||
	    t->bigdirendmasseq != h->startmasseq ||
	    t->reserved[0] != 0 || t->reserved[1] != 0) {
		adfs_error(sb, "dir %06x has malformed tail", id);
		goto out;
	}

	dir->parent_id = le32_to_cpu(h->bigdirparent);
	return 0;

out:
	adfs_dir_relse(dir);

	return ret;
}

static int
adfs_fplus_setpos(struct adfs_dir *dir, unsigned int fpos)
{
	struct adfs_bigdirheader *h =
		(struct adfs_bigdirheader *) dir->bhs[0]->b_data;
	int ret = -ENOENT;

	if (fpos <= le32_to_cpu(h->bigdirentries)) {
		dir->pos = fpos;
		ret = 0;
	}

	return ret;
}

static int
adfs_fplus_getnext(struct adfs_dir *dir, struct object_info *obj)
{
	struct adfs_bigdirheader *h =
		(struct adfs_bigdirheader *) dir->bhs[0]->b_data;
	struct adfs_bigdirentry bde;
	unsigned int offset;
	int ret;

	if (dir->pos >= le32_to_cpu(h->bigdirentries))
		return -ENOENT;

	offset = offsetof(struct adfs_bigdirheader, bigdirname);
	offset += ((le32_to_cpu(h->bigdirnamelen) + 4) & ~3);
	offset += dir->pos * sizeof(struct adfs_bigdirentry);

	ret = adfs_dir_copyfrom(&bde, dir, offset,
				sizeof(struct adfs_bigdirentry));
	if (ret)
		return ret;

	obj->loadaddr = le32_to_cpu(bde.bigdirload);
	obj->execaddr = le32_to_cpu(bde.bigdirexec);
	obj->size     = le32_to_cpu(bde.bigdirlen);
	obj->indaddr  = le32_to_cpu(bde.bigdirindaddr);
	obj->attr     = le32_to_cpu(bde.bigdirattr);
	obj->name_len = le32_to_cpu(bde.bigdirobnamelen);

	offset = offsetof(struct adfs_bigdirheader, bigdirname);
	offset += ((le32_to_cpu(h->bigdirnamelen) + 4) & ~3);
	offset += le32_to_cpu(h->bigdirentries) * sizeof(struct adfs_bigdirentry);
	offset += le32_to_cpu(bde.bigdirobnameptr);

	ret = adfs_dir_copyfrom(obj->name, dir, offset, obj->name_len);
	if (ret)
		return ret;

	adfs_object_fixup(dir, obj);

	dir->pos += 1;

	return 0;
}

const struct adfs_dir_ops adfs_fplus_dir_ops = {
	.read		= adfs_fplus_read,
	.setpos		= adfs_fplus_setpos,
	.getnext	= adfs_fplus_getnext,
};