1 files changed, 287 insertions, 0 deletions
diff --git a/fs/adfs/dir_fplus.c b/fs/adfs/dir_fplus.c
new file mode 100644
index 000000000..4a1592401
--- /dev/null
+++ b/fs/adfs/dir_fplus.c
@@ -0,0 +1,287 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  linux/fs/adfs/dir_fplus.c
+ *
+ *  Copyright (C) 1997-1999 Russell King
+ */
+#include "adfs.h"
+#include "dir_fplus.h"
+
+/* Return the byte offset to directory entry pos */
+static unsigned int adfs_fplus_offset(const struct adfs_bigdirheader *h,
+				      unsigned int pos)
+{
+	return offsetof(struct adfs_bigdirheader, bigdirname) +
+	       ALIGN(le32_to_cpu(h->bigdirnamelen), 4) +
+	       pos * sizeof(struct adfs_bigdirentry);
+}
+
+static int adfs_fplus_validate_header(const struct adfs_bigdirheader *h)
+{
+	unsigned int size = le32_to_cpu(h->bigdirsize);
+	unsigned int len;
+
+	if (h->bigdirversion[0] != 0 || h->bigdirversion[1] != 0 ||
+	    h->bigdirversion[2] != 0 ||
+	    h->bigdirstartname != cpu_to_le32(BIGDIRSTARTNAME) ||
+	    !size || size & 2047 || size > SZ_4M)
+		return -EIO;
+
+	size -= sizeof(struct adfs_bigdirtail) +
+		offsetof(struct adfs_bigdirheader, bigdirname);
+
+	/* Check that bigdirnamelen fits within the directory */
+	len = ALIGN(le32_to_cpu(h->bigdirnamelen), 4);
+	if (len > size)
+		return -EIO;
+
+	size -= len;
+
+	/* Check that bigdirnamesize fits within the directory */
+	len = le32_to_cpu(h->bigdirnamesize);
+	if (len > size)
+		return -EIO;
+
+	size -= len;
+
+	/*
+	 * Avoid division, we know that absolute maximum number of entries
+	 * can not be so large to cause overflow of the multiplication below.
+	 */
+	len = le32_to_cpu(h->bigdirentries);
+	if (len > SZ_4M / sizeof(struct adfs_bigdirentry) ||
+	    len * sizeof(struct adfs_bigdirentry) > size)
+		return -EIO;
+
+	return 0;
+}
+
+static int adfs_fplus_validate_tail(const struct adfs_bigdirheader *h,
+				    const struct adfs_bigdirtail *t)
+{
+	if (t->bigdirendname != cpu_to_le32(BIGDIRENDNAME) ||
+	    t->bigdirendmasseq != h->startmasseq ||
+	    t->reserved[0] != 0 || t->reserved[1] != 0)
+		return -EIO;
+
+	return 0;
+}
+
+static u8 adfs_fplus_checkbyte(struct adfs_dir *dir)
+{
+	struct adfs_bigdirheader *h = dir->bighead;
+	struct adfs_bigdirtail *t = dir->bigtail;
+	unsigned int end, bs, bi, i;
+	__le32 *bp;
+	u32 dircheck;
+
+	end = adfs_fplus_offset(h, le32_to_cpu(h->bigdirentries)) +
+		le32_to_cpu(h->bigdirnamesize);
+
+	/* Accumulate the contents of the header, entries and names */
+	for (dircheck = 0, bi = 0; end; bi++) {
+		bp = (void *)dir->bhs[bi]->b_data;
+		bs = dir->bhs[bi]->b_size;
+		if (bs > end)
+			bs = end;
+
+		for (i = 0; i < bs; i += sizeof(u32))
+			dircheck = ror32(dircheck, 13) ^ le32_to_cpup(bp++);
+
+		end -= bs;
+	}
+
+	/* Accumulate the contents of the tail except for the check byte */
+	dircheck = ror32(dircheck, 13) ^ le32_to_cpu(t->bigdirendname);
+	dircheck = ror32(dircheck, 13) ^ t->bigdirendmasseq;
+	dircheck = ror32(dircheck, 13) ^ t->reserved[0];
+	dircheck = ror32(dircheck, 13) ^ t->reserved[1];
+
+	return dircheck ^ dircheck >> 8 ^ dircheck >> 16 ^ dircheck >> 24;
+}
+
+static int adfs_fplus_read(struct super_block *sb, u32 indaddr,
+			   unsigned int size, struct adfs_dir *dir)
+{
+	struct adfs_bigdirheader *h;
+	struct adfs_bigdirtail *t;
+	unsigned int dirsize;
+	int ret;
+
+	/* Read first buffer */
+	ret = adfs_dir_read_buffers(sb, indaddr, sb->s_blocksize, dir);
+	if (ret)
+		return ret;
+
+	dir->bighead = h = (void *)dir->bhs[0]->b_data;
+	ret = adfs_fplus_validate_header(h);
+	if (ret) {
+		adfs_error(sb, "dir %06x has malformed header", indaddr);
+		goto out;
+	}
+
+	dirsize = le32_to_cpu(h->bigdirsize);
+	if (size && dirsize != size) {
+		adfs_msg(sb, KERN_WARNING,
+			 "dir %06x header size %X does not match directory size %X",
+			 indaddr, dirsize, size);
+	}
+
+	/* Read remaining buffers */
+	ret = adfs_dir_read_buffers(sb, indaddr, dirsize, dir);
+	if (ret)
+		return ret;
+
+	dir->bigtail = t = (struct adfs_bigdirtail *)
+		(dir->bhs[dir->nr_buffers - 1]->b_data + (sb->s_blocksize - 8));
+
+	ret = adfs_fplus_validate_tail(h, t);
+	if (ret) {
+		adfs_error(sb, "dir %06x has malformed tail", indaddr);
+		goto out;
+	}
+
+	if (adfs_fplus_checkbyte(dir) != t->bigdircheckbyte) {
+		adfs_error(sb, "dir %06x checkbyte mismatch\n", indaddr);
+		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)
+{
+	int ret = -ENOENT;
+
+	if (fpos <= le32_to_cpu(dir->bighead->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 = dir->bighead;
+	struct adfs_bigdirentry bde;
+	unsigned int offset;
+	int ret;
+
+	if (dir->pos >= le32_to_cpu(h->bigdirentries))
+		return -ENOENT;
+
+	offset = adfs_fplus_offset(h, dir->pos);
+
+	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 = adfs_fplus_offset(h, le32_to_cpu(h->bigdirentries));
+	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;
+}
+
+static int adfs_fplus_iterate(struct adfs_dir *dir, struct dir_context *ctx)
+{
+	struct object_info obj;
+
+	if ((ctx->pos - 2) >> 32)
+		return 0;
+
+	if (adfs_fplus_setpos(dir, ctx->pos - 2))
+		return 0;
+
+	while (!adfs_fplus_getnext(dir, &obj)) {
+		if (!dir_emit(ctx, obj.name, obj.name_len,
+			      obj.indaddr, DT_UNKNOWN))
+			break;
+		ctx->pos++;
+	}
+
+	return 0;
+}
+
+static int adfs_fplus_update(struct adfs_dir *dir, struct object_info *obj)
+{
+	struct adfs_bigdirheader *h = dir->bighead;
+	struct adfs_bigdirentry bde;
+	int offset, end, ret;
+
+	offset = adfs_fplus_offset(h, 0) - sizeof(bde);
+	end = adfs_fplus_offset(h, le32_to_cpu(h->bigdirentries));
+
+	do {
+		offset += sizeof(bde);
+		if (offset >= end) {
+			adfs_error(dir->sb, "unable to locate entry to update");
+			return -ENOENT;
+		}
+		ret = adfs_dir_copyfrom(&bde, dir, offset, sizeof(bde));
+		if (ret) {
+			adfs_error(dir->sb, "error reading directory entry");
+			return -ENOENT;
+		}
+	} while (le32_to_cpu(bde.bigdirindaddr) != obj->indaddr);
+
+	bde.bigdirload    = cpu_to_le32(obj->loadaddr);
+	bde.bigdirexec    = cpu_to_le32(obj->execaddr);
+	bde.bigdirlen     = cpu_to_le32(obj->size);
+	bde.bigdirindaddr = cpu_to_le32(obj->indaddr);
+	bde.bigdirattr    = cpu_to_le32(obj->attr);
+
+	return adfs_dir_copyto(dir, offset, &bde, sizeof(bde));
+}
+
+static int adfs_fplus_commit(struct adfs_dir *dir)
+{
+	int ret;
+
+	/* Increment directory sequence number */
+	dir->bighead->startmasseq += 1;
+	dir->bigtail->bigdirendmasseq += 1;
+
+	/* Update directory check byte */
+	dir->bigtail->bigdircheckbyte = adfs_fplus_checkbyte(dir);
+
+	/* Make sure the directory still validates correctly */
+	ret = adfs_fplus_validate_header(dir->bighead);
+	if (ret == 0)
+		ret = adfs_fplus_validate_tail(dir->bighead, dir->bigtail);
+
+	return ret;
+}
+
+const struct adfs_dir_ops adfs_fplus_dir_ops = {
+	.read		= adfs_fplus_read,
+	.iterate	= adfs_fplus_iterate,
+	.setpos		= adfs_fplus_setpos,
+	.getnext	= adfs_fplus_getnext,
+	.update		= adfs_fplus_update,
+	.commit		= adfs_fplus_commit,
+};