// SPDX-License-Identifier: GPL-2.0

  /*
   *  linux/fs/hpfs/map.c
   *
   *  Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz), 1998-1999
   *
   *  mapping structures to memory with some minimal checks
   */
  
  #include "hpfs_fn.h"

  __le32 *hpfs_map_dnode_bitmap(struct super_block *s, struct quad_buffer_head *qbh)

  {
  	return hpfs_map_4sectors(s, hpfs_sb(s)->sb_dmap, qbh, 0);
  }

  __le32 *hpfs_map_bitmap(struct super_block *s, unsigned bmp_block,

  			 struct quad_buffer_head *qbh, char *id)
  {
  	secno sec;

  	__le32 *ret;

  	unsigned n_bands = (hpfs_sb(s)->sb_fs_size + 0x3fff) >> 14;
  	if (hpfs_sb(s)->sb_chk) if (bmp_block >= n_bands) {

  		hpfs_error(s, "hpfs_map_bitmap called with bad parameter: %08x at %s", bmp_block, id);
  		return NULL;
  	}

  	sec = le32_to_cpu(hpfs_sb(s)->sb_bmp_dir[bmp_block]);

  	if (!sec || sec > hpfs_sb(s)->sb_fs_size-4) {
  		hpfs_error(s, "invalid bitmap block pointer %08x -> %08x at %s", bmp_block, sec, id);
  		return NULL;
  	}

  	ret = hpfs_map_4sectors(s, sec, qbh, 4);
  	if (ret) hpfs_prefetch_bitmap(s, bmp_block + 1);
  	return ret;
  }
  
  void hpfs_prefetch_bitmap(struct super_block *s, unsigned bmp_block)
  {
  	unsigned to_prefetch, next_prefetch;
  	unsigned n_bands = (hpfs_sb(s)->sb_fs_size + 0x3fff) >> 14;
  	if (unlikely(bmp_block >= n_bands))
  		return;
  	to_prefetch = le32_to_cpu(hpfs_sb(s)->sb_bmp_dir[bmp_block]);
  	if (unlikely(bmp_block + 1 >= n_bands))
  		next_prefetch = 0;
  	else
  		next_prefetch = le32_to_cpu(hpfs_sb(s)->sb_bmp_dir[bmp_block + 1]);
  	hpfs_prefetch_sectors(s, to_prefetch, 4 + 4 * (to_prefetch + 4 == next_prefetch));

  }
  
  /*
   * Load first code page into kernel memory, return pointer to 256-byte array,
   * first 128 bytes are uppercasing table for chars 128-255, next 128 bytes are
   * lowercasing table
   */

  unsigned char *hpfs_load_code_page(struct super_block *s, secno cps)

  {
  	struct buffer_head *bh;
  	secno cpds;
  	unsigned cpi;
  	unsigned char *ptr;
  	unsigned char *cp_table;
  	int i;
  	struct code_page_data *cpd;
  	struct code_page_directory *cp = hpfs_map_sector(s, cps, &bh, 0);
  	if (!cp) return NULL;

  	if (le32_to_cpu(cp->magic) != CP_DIR_MAGIC) {

  		pr_err("Code page directory magic doesn't match (magic = %08x)
  ",

  			le32_to_cpu(cp->magic));

  		brelse(bh);
  		return NULL;
  	}

  	if (!le32_to_cpu(cp->n_code_pages)) {

  		pr_err("n_code_pages == 0
  ");

  		brelse(bh);
  		return NULL;
  	}

  	cpds = le32_to_cpu(cp->array[0].code_page_data);
  	cpi = le16_to_cpu(cp->array[0].index);

  	brelse(bh);
  
  	if (cpi >= 3) {

  		pr_err("Code page index out of array
  ");

  		return NULL;
  	}
  	
  	if (!(cpd = hpfs_map_sector(s, cpds, &bh, 0))) return NULL;

  	if (le16_to_cpu(cpd->offs[cpi]) > 0x178) {

  		pr_err("Code page index out of sector
  ");

  		brelse(bh);
  		return NULL;
  	}

  	ptr = (unsigned char *)cpd + le16_to_cpu(cpd->offs[cpi]) + 6;

  	if (!(cp_table = kmalloc(256, GFP_KERNEL))) {

  		pr_err("out of memory for code page table
  ");

  		brelse(bh);
  		return NULL;
  	}
  	memcpy(cp_table, ptr, 128);
  	brelse(bh);
  
  	/* Try to build lowercasing table from uppercasing one */
  
  	for (i=128; i<256; i++) cp_table[i]=i;
  	for (i=128; i<256; i++) if (cp_table[i-128]!=i && cp_table[i-128]>=128)
  		cp_table[cp_table[i-128]] = i;
  	
  	return cp_table;
  }

  __le32 *hpfs_load_bitmap_directory(struct super_block *s, secno bmp)

  {
  	struct buffer_head *bh;
  	int n = (hpfs_sb(s)->sb_fs_size + 0x200000 - 1) >> 21;
  	int i;

  	__le32 *b;

  	if (!(b = kmalloc_array(n, 512, GFP_KERNEL))) {

  		pr_err("can't allocate memory for bitmap directory
  ");

  		return NULL;
  	}	
  	for (i=0;i<n;i++) {

  		__le32 *d = hpfs_map_sector(s, bmp+i, &bh, n - i - 1);

  		if (!d) {
  			kfree(b);
  			return NULL;
  		}
  		memcpy((char *)b + 512 * i, d, 512);
  		brelse(bh);
  	}
  	return b;
  }

  void hpfs_load_hotfix_map(struct super_block *s, struct hpfs_spare_block *spareblock)
  {
  	struct quad_buffer_head qbh;

  	__le32 *directory;

  	u32 n_hotfixes, n_used_hotfixes;
  	unsigned i;
  
  	n_hotfixes = le32_to_cpu(spareblock->n_spares);
  	n_used_hotfixes = le32_to_cpu(spareblock->n_spares_used);
  
  	if (n_hotfixes > 256 || n_used_hotfixes > n_hotfixes) {
  		hpfs_error(s, "invalid number of hotfixes: %u, used: %u", n_hotfixes, n_used_hotfixes);
  		return;
  	}
  	if (!(directory = hpfs_map_4sectors(s, le32_to_cpu(spareblock->hotfix_map), &qbh, 0))) {
  		hpfs_error(s, "can't load hotfix map");
  		return;
  	}
  	for (i = 0; i < n_used_hotfixes; i++) {
  		hpfs_sb(s)->hotfix_from[i] = le32_to_cpu(directory[i]);
  		hpfs_sb(s)->hotfix_to[i] = le32_to_cpu(directory[n_hotfixes + i]);
  	}
  	hpfs_sb(s)->n_hotfixes = n_used_hotfixes;
  	hpfs_brelse4(&qbh);
  }

  /*
   * Load fnode to memory
   */
  
  struct fnode *hpfs_map_fnode(struct super_block *s, ino_t ino, struct buffer_head **bhp)
  {
  	struct fnode *fnode;
  	if (hpfs_sb(s)->sb_chk) if (hpfs_chk_sectors(s, ino, 1, "fnode")) {
  		return NULL;
  	}
  	if ((fnode = hpfs_map_sector(s, ino, bhp, FNODE_RD_AHEAD))) {
  		if (hpfs_sb(s)->sb_chk) {
  			struct extended_attribute *ea;
  			struct extended_attribute *ea_end;

  			if (le32_to_cpu(fnode->magic) != FNODE_MAGIC) {

  				hpfs_error(s, "bad magic on fnode %08lx",
  					(unsigned long)ino);

  				goto bail;
  			}

  			if (!fnode_is_dir(fnode)) {

  				if ((unsigned)fnode->btree.n_used_nodes + (unsigned)fnode->btree.n_free_nodes !=

  				    (bp_internal(&fnode->btree) ? 12 : 8)) {

  					hpfs_error(s,
  					   "bad number of nodes in fnode %08lx",
  					    (unsigned long)ino);

  					goto bail;
  				}

  				if (le16_to_cpu(fnode->btree.first_free) !=

  				    8 + fnode->btree.n_used_nodes * (bp_internal(&fnode->btree) ? 8 : 12)) {

  					hpfs_error(s,
  					    "bad first_free pointer in fnode %08lx",
  					    (unsigned long)ino);

  					goto bail;
  				}
  			}

  			if (le16_to_cpu(fnode->ea_size_s) && (le16_to_cpu(fnode->ea_offs) < 0xc4 ||
  			   le16_to_cpu(fnode->ea_offs) + le16_to_cpu(fnode->acl_size_s) + le16_to_cpu(fnode->ea_size_s) > 0x200)) {

  				hpfs_error(s,
  					"bad EA info in fnode %08lx: ea_offs == %04x ea_size_s == %04x",
  					(unsigned long)ino,

  					le16_to_cpu(fnode->ea_offs), le16_to_cpu(fnode->ea_size_s));

  				goto bail;
  			}
  			ea = fnode_ea(fnode);
  			ea_end = fnode_end_ea(fnode);
  			while (ea != ea_end) {
  				if (ea > ea_end) {

  					hpfs_error(s, "bad EA in fnode %08lx",
  						(unsigned long)ino);

  					goto bail;
  				}
  				ea = next_ea(ea);
  			}
  		}
  	}
  	return fnode;
  	bail:
  	brelse(*bhp);
  	return NULL;
  }
  
  struct anode *hpfs_map_anode(struct super_block *s, anode_secno ano, struct buffer_head **bhp)
  {
  	struct anode *anode;
  	if (hpfs_sb(s)->sb_chk) if (hpfs_chk_sectors(s, ano, 1, "anode")) return NULL;
  	if ((anode = hpfs_map_sector(s, ano, bhp, ANODE_RD_AHEAD)))
  		if (hpfs_sb(s)->sb_chk) {

  			if (le32_to_cpu(anode->magic) != ANODE_MAGIC) {

  				hpfs_error(s, "bad magic on anode %08x", ano);
  				goto bail;
  			}

  			if (le32_to_cpu(anode->self) != ano) {
  				hpfs_error(s, "self pointer invalid on anode %08x", ano);
  				goto bail;
  			}

  			if ((unsigned)anode->btree.n_used_nodes + (unsigned)anode->btree.n_free_nodes !=

  			    (bp_internal(&anode->btree) ? 60 : 40)) {

  				hpfs_error(s, "bad number of nodes in anode %08x", ano);
  				goto bail;
  			}

  			if (le16_to_cpu(anode->btree.first_free) !=

  			    8 + anode->btree.n_used_nodes * (bp_internal(&anode->btree) ? 8 : 12)) {

  				hpfs_error(s, "bad first_free pointer in anode %08x", ano);
  				goto bail;
  			}
  		}
  	return anode;
  	bail:
  	brelse(*bhp);
  	return NULL;
  }
  
  /*
   * Load dnode to memory and do some checks
   */
  
  struct dnode *hpfs_map_dnode(struct super_block *s, unsigned secno,
  			     struct quad_buffer_head *qbh)
  {
  	struct dnode *dnode;
  	if (hpfs_sb(s)->sb_chk) {
  		if (hpfs_chk_sectors(s, secno, 4, "dnode")) return NULL;
  		if (secno & 3) {
  			hpfs_error(s, "dnode %08x not byte-aligned", secno);
  			return NULL;
  		}	
  	}
  	if ((dnode = hpfs_map_4sectors(s, secno, qbh, DNODE_RD_AHEAD)))
  		if (hpfs_sb(s)->sb_chk) {
  			unsigned p, pp = 0;

  			unsigned char *d = (unsigned char *)dnode;

  			int b = 0;

  			if (le32_to_cpu(dnode->magic) != DNODE_MAGIC) {

  				hpfs_error(s, "bad magic on dnode %08x", secno);
  				goto bail;
  			}

  			if (le32_to_cpu(dnode->self) != secno)
  				hpfs_error(s, "bad self pointer on dnode %08x self = %08x", secno, le32_to_cpu(dnode->self));

  			/* Check dirents - bad dirents would cause infinite
  			   loops or shooting to memory */

  			if (le32_to_cpu(dnode->first_free) > 2048) {
  				hpfs_error(s, "dnode %08x has first_free == %08x", secno, le32_to_cpu(dnode->first_free));

  				goto bail;
  			}

  			for (p = 20; p < le32_to_cpu(dnode->first_free); p += d[p] + (d[p+1] << 8)) {

  				struct hpfs_dirent *de = (struct hpfs_dirent *)((char *)dnode + p);

  				if (le16_to_cpu(de->length) > 292 || (le16_to_cpu(de->length) < 32) || (le16_to_cpu(de->length) & 3) || p + le16_to_cpu(de->length) > 2048) {

  					hpfs_error(s, "bad dirent size in dnode %08x, dirent %03x, last %03x", secno, p, pp);
  					goto bail;
  				}

  				if (((31 + de->namelen + de->down*4 + 3) & ~3) != le16_to_cpu(de->length)) {

  					if (((31 + de->namelen + de->down*4 + 3) & ~3) < le16_to_cpu(de->length) && s->s_flags & SB_RDONLY) goto ok;

  					hpfs_error(s, "namelen does not match dirent size in dnode %08x, dirent %03x, last %03x", secno, p, pp);
  					goto bail;
  				}
  				ok:
  				if (hpfs_sb(s)->sb_chk >= 2) b |= 1 << de->down;
  				if (de->down) if (de_down_pointer(de) < 0x10) {
  					hpfs_error(s, "bad down pointer in dnode %08x, dirent %03x, last %03x", secno, p, pp);
  					goto bail;
  				}
  				pp = p;
  				
  			}

  			if (p != le32_to_cpu(dnode->first_free)) {

  				hpfs_error(s, "size on last dirent does not match first_free; dnode %08x", secno);
  				goto bail;
  			}
  			if (d[pp + 30] != 1 || d[pp + 31] != 255) {
  				hpfs_error(s, "dnode %08x does not end with \\377 entry", secno);
  				goto bail;
  			}

  			if (b == 3)

  				pr_err("unbalanced dnode tree, dnode %08x; see hpfs.txt 4 more info
  ",

  					secno);

  		}
  	return dnode;
  	bail:
  	hpfs_brelse4(qbh);
  	return NULL;
  }
  
  dnode_secno hpfs_fnode_dno(struct super_block *s, ino_t ino)
  {
  	struct buffer_head *bh;
  	struct fnode *fnode;
  	dnode_secno dno;
  
  	fnode = hpfs_map_fnode(s, ino, &bh);
  	if (!fnode)
  		return 0;

  	dno = le32_to_cpu(fnode->u.external[0].disk_secno);

  	brelse(bh);
  	return dno;
  }