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