root/block/partitions/amiga.c

DEFINITIONS

1. checksum_block
2. amiga_partition

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  fs/partitions/amiga.c
   4  *
   5  *  Code extracted from drivers/block/genhd.c
   6  *
   7  *  Copyright (C) 1991-1998  Linus Torvalds
   8  *  Re-organised Feb 1998 Russell King
   9  */
  10 
  11 #define pr_fmt(fmt) fmt
  12 
  13 #include <linux/types.h>
  14 #include <linux/affs_hardblocks.h>
  15 
  16 #include "check.h"
  17 #include "amiga.h"
  18 
  19 static __inline__ u32
  20 checksum_block(__be32 *m, int size)
  21 {
  22         u32 sum = 0;
  23 
  24         while (size--)
  25                 sum += be32_to_cpu(*m++);
  26         return sum;
  27 }
  28 
  29 int amiga_partition(struct parsed_partitions *state)
  30 {
  31         Sector sect;
  32         unsigned char *data;
  33         struct RigidDiskBlock *rdb;
  34         struct PartitionBlock *pb;
  35         int start_sect, nr_sects, blk, part, res = 0;
  36         int blksize = 1;        /* Multiplier for disk block size */
  37         int slot = 1;
  38         char b[BDEVNAME_SIZE];
  39 
  40         for (blk = 0; ; blk++, put_dev_sector(sect)) {
  41                 if (blk == RDB_ALLOCATION_LIMIT)
  42                         goto rdb_done;
  43                 data = read_part_sector(state, blk, &sect);
  44                 if (!data) {
  45                         if (warn_no_part)
  46                                 pr_err("Dev %s: unable to read RDB block %d\n",
  47                                        bdevname(state->bdev, b), blk);
  48                         res = -1;
  49                         goto rdb_done;
  50                 }
  51                 if (*(__be32 *)data != cpu_to_be32(IDNAME_RIGIDDISK))
  52                         continue;
  53 
  54                 rdb = (struct RigidDiskBlock *)data;
  55                 if (checksum_block((__be32 *)data, be32_to_cpu(rdb->rdb_SummedLongs) & 0x7F) == 0)
  56                         break;
  57                 /* Try again with 0xdc..0xdf zeroed, Windows might have
  58                  * trashed it.
  59                  */
  60                 *(__be32 *)(data+0xdc) = 0;
  61                 if (checksum_block((__be32 *)data,
  62                                 be32_to_cpu(rdb->rdb_SummedLongs) & 0x7F)==0) {
  63                         pr_err("Trashed word at 0xd0 in block %d ignored in checksum calculation\n",
  64                                blk);
  65                         break;
  66                 }
  67 
  68                 pr_err("Dev %s: RDB in block %d has bad checksum\n",
  69                        bdevname(state->bdev, b), blk);
  70         }
  71 
  72         /* blksize is blocks per 512 byte standard block */
  73         blksize = be32_to_cpu( rdb->rdb_BlockBytes ) / 512;
  74 
  75         {
  76                 char tmp[7 + 10 + 1 + 1];
  77 
  78                 /* Be more informative */
  79                 snprintf(tmp, sizeof(tmp), " RDSK (%d)", blksize * 512);
  80                 strlcat(state->pp_buf, tmp, PAGE_SIZE);
  81         }
  82         blk = be32_to_cpu(rdb->rdb_PartitionList);
  83         put_dev_sector(sect);
  84         for (part = 1; blk>0 && part<=16; part++, put_dev_sector(sect)) {
  85                 blk *= blksize; /* Read in terms partition table understands */
  86                 data = read_part_sector(state, blk, &sect);
  87                 if (!data) {
  88                         if (warn_no_part)
  89                                 pr_err("Dev %s: unable to read partition block %d\n",
  90                                        bdevname(state->bdev, b), blk);
  91                         res = -1;
  92                         goto rdb_done;
  93                 }
  94                 pb  = (struct PartitionBlock *)data;
  95                 blk = be32_to_cpu(pb->pb_Next);
  96                 if (pb->pb_ID != cpu_to_be32(IDNAME_PARTITION))
  97                         continue;
  98                 if (checksum_block((__be32 *)pb, be32_to_cpu(pb->pb_SummedLongs) & 0x7F) != 0 )
  99                         continue;
 100 
 101                 /* Tell Kernel about it */
 102 
 103                 nr_sects = (be32_to_cpu(pb->pb_Environment[10]) + 1 -
 104                             be32_to_cpu(pb->pb_Environment[9])) *
 105                            be32_to_cpu(pb->pb_Environment[3]) *
 106                            be32_to_cpu(pb->pb_Environment[5]) *
 107                            blksize;
 108                 if (!nr_sects)
 109                         continue;
 110                 start_sect = be32_to_cpu(pb->pb_Environment[9]) *
 111                              be32_to_cpu(pb->pb_Environment[3]) *
 112                              be32_to_cpu(pb->pb_Environment[5]) *
 113                              blksize;
 114                 put_partition(state,slot++,start_sect,nr_sects);
 115                 {
 116                         /* Be even more informative to aid mounting */
 117                         char dostype[4];
 118                         char tmp[42];
 119 
 120                         __be32 *dt = (__be32 *)dostype;
 121                         *dt = pb->pb_Environment[16];
 122                         if (dostype[3] < ' ')
 123                                 snprintf(tmp, sizeof(tmp), " (%c%c%c^%c)",
 124                                         dostype[0], dostype[1],
 125                                         dostype[2], dostype[3] + '@' );
 126                         else
 127                                 snprintf(tmp, sizeof(tmp), " (%c%c%c%c)",
 128                                         dostype[0], dostype[1],
 129                                         dostype[2], dostype[3]);
 130                         strlcat(state->pp_buf, tmp, PAGE_SIZE);
 131                         snprintf(tmp, sizeof(tmp), "(res %d spb %d)",
 132                                 be32_to_cpu(pb->pb_Environment[6]),
 133                                 be32_to_cpu(pb->pb_Environment[4]));
 134                         strlcat(state->pp_buf, tmp, PAGE_SIZE);
 135                 }
 136                 res = 1;
 137         }
 138         strlcat(state->pp_buf, "\n", PAGE_SIZE);
 139 
 140 rdb_done:
 141         return res;
 142 }