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-rw-r--r--fs/adfs/dir_fplus.c287
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 0000000000..4a15924014
--- /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,
+};
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