diff options
Diffstat (limited to 'block/partitions/amiga.c')
| -rw-r--r-- | block/partitions/amiga.c | 207 |
1 files changed, 207 insertions, 0 deletions
diff --git a/block/partitions/amiga.c b/block/partitions/amiga.c new file mode 100644 index 000000000..a99ec7f1a --- /dev/null +++ b/block/partitions/amiga.c @@ -0,0 +1,207 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * fs/partitions/amiga.c + * + * Code extracted from drivers/block/genhd.c + * + * Copyright (C) 1991-1998 Linus Torvalds + * Re-organised Feb 1998 Russell King + */ + +#define pr_fmt(fmt) fmt + +#include <linux/types.h> +#include <linux/mm_types.h> +#include <linux/overflow.h> +#include <linux/affs_hardblocks.h> + +#include "check.h" + +/* magic offsets in partition DosEnvVec */ +#define NR_HD 3 +#define NR_SECT 5 +#define LO_CYL 9 +#define HI_CYL 10 + +static __inline__ u32 +checksum_block(__be32 *m, int size) +{ + u32 sum = 0; + + while (size--) + sum += be32_to_cpu(*m++); + return sum; +} + +int amiga_partition(struct parsed_partitions *state) +{ + Sector sect; + unsigned char *data; + struct RigidDiskBlock *rdb; + struct PartitionBlock *pb; + u64 start_sect, nr_sects; + sector_t blk, end_sect; + u32 cylblk; /* rdb_CylBlocks = nr_heads*sect_per_track */ + u32 nr_hd, nr_sect, lo_cyl, hi_cyl; + int part, res = 0; + unsigned int blksize = 1; /* Multiplier for disk block size */ + int slot = 1; + char b[BDEVNAME_SIZE]; + + for (blk = 0; ; blk++, put_dev_sector(sect)) { + if (blk == RDB_ALLOCATION_LIMIT) + goto rdb_done; + data = read_part_sector(state, blk, §); + if (!data) { + pr_err("Dev %s: unable to read RDB block %llu\n", + bdevname(state->bdev, b), blk); + res = -1; + goto rdb_done; + } + if (*(__be32 *)data != cpu_to_be32(IDNAME_RIGIDDISK)) + continue; + + rdb = (struct RigidDiskBlock *)data; + if (checksum_block((__be32 *)data, be32_to_cpu(rdb->rdb_SummedLongs) & 0x7F) == 0) + break; + /* Try again with 0xdc..0xdf zeroed, Windows might have + * trashed it. + */ + *(__be32 *)(data+0xdc) = 0; + if (checksum_block((__be32 *)data, + be32_to_cpu(rdb->rdb_SummedLongs) & 0x7F)==0) { + pr_err("Trashed word at 0xd0 in block %llu ignored in checksum calculation\n", + blk); + break; + } + + pr_err("Dev %s: RDB in block %llu has bad checksum\n", + bdevname(state->bdev, b), blk); + } + + /* blksize is blocks per 512 byte standard block */ + blksize = be32_to_cpu( rdb->rdb_BlockBytes ) / 512; + + { + char tmp[7 + 10 + 1 + 1]; + + /* Be more informative */ + snprintf(tmp, sizeof(tmp), " RDSK (%d)", blksize * 512); + strlcat(state->pp_buf, tmp, PAGE_SIZE); + } + blk = be32_to_cpu(rdb->rdb_PartitionList); + put_dev_sector(sect); + for (part = 1; (s32) blk>0 && part<=16; part++, put_dev_sector(sect)) { + /* Read in terms partition table understands */ + if (check_mul_overflow(blk, (sector_t) blksize, &blk)) { + pr_err("Dev %s: overflow calculating partition block %llu! Skipping partitions %u and beyond\n", + bdevname(state->bdev, b), blk, part); + break; + } + data = read_part_sector(state, blk, §); + if (!data) { + pr_err("Dev %s: unable to read partition block %llu\n", + bdevname(state->bdev, b), blk); + res = -1; + goto rdb_done; + } + pb = (struct PartitionBlock *)data; + blk = be32_to_cpu(pb->pb_Next); + if (pb->pb_ID != cpu_to_be32(IDNAME_PARTITION)) + continue; + if (checksum_block((__be32 *)pb, be32_to_cpu(pb->pb_SummedLongs) & 0x7F) != 0 ) + continue; + + /* RDB gives us more than enough rope to hang ourselves with, + * many times over (2^128 bytes if all fields max out). + * Some careful checks are in order, so check for potential + * overflows. + * We are multiplying four 32 bit numbers to one sector_t! + */ + + nr_hd = be32_to_cpu(pb->pb_Environment[NR_HD]); + nr_sect = be32_to_cpu(pb->pb_Environment[NR_SECT]); + + /* CylBlocks is total number of blocks per cylinder */ + if (check_mul_overflow(nr_hd, nr_sect, &cylblk)) { + pr_err("Dev %s: heads*sects %u overflows u32, skipping partition!\n", + bdevname(state->bdev, b), cylblk); + continue; + } + + /* check for consistency with RDB defined CylBlocks */ + if (cylblk > be32_to_cpu(rdb->rdb_CylBlocks)) { + pr_warn("Dev %s: cylblk %u > rdb_CylBlocks %u!\n", + bdevname(state->bdev, b), cylblk, + be32_to_cpu(rdb->rdb_CylBlocks)); + } + + /* RDB allows for variable logical block size - + * normalize to 512 byte blocks and check result. + */ + + if (check_mul_overflow(cylblk, blksize, &cylblk)) { + pr_err("Dev %s: partition %u bytes per cyl. overflows u32, skipping partition!\n", + bdevname(state->bdev, b), part); + continue; + } + + /* Calculate partition start and end. Limit of 32 bit on cylblk + * guarantees no overflow occurs if LBD support is enabled. + */ + + lo_cyl = be32_to_cpu(pb->pb_Environment[LO_CYL]); + start_sect = ((u64) lo_cyl * cylblk); + + hi_cyl = be32_to_cpu(pb->pb_Environment[HI_CYL]); + nr_sects = (((u64) hi_cyl - lo_cyl + 1) * cylblk); + + if (!nr_sects) + continue; + + /* Warn user if partition end overflows u32 (AmigaDOS limit) */ + + if ((start_sect + nr_sects) > UINT_MAX) { + pr_warn("Dev %s: partition %u (%llu-%llu) needs 64 bit device support!\n", + bdevname(state->bdev, b), part, + start_sect, start_sect + nr_sects); + } + + if (check_add_overflow(start_sect, nr_sects, &end_sect)) { + pr_err("Dev %s: partition %u (%llu-%llu) needs LBD device support, skipping partition!\n", + bdevname(state->bdev, b), part, + start_sect, end_sect); + continue; + } + + /* Tell Kernel about it */ + + put_partition(state,slot++,start_sect,nr_sects); + { + /* Be even more informative to aid mounting */ + char dostype[4]; + char tmp[42]; + + __be32 *dt = (__be32 *)dostype; + *dt = pb->pb_Environment[16]; + if (dostype[3] < ' ') + snprintf(tmp, sizeof(tmp), " (%c%c%c^%c)", + dostype[0], dostype[1], + dostype[2], dostype[3] + '@' ); + else + snprintf(tmp, sizeof(tmp), " (%c%c%c%c)", + dostype[0], dostype[1], + dostype[2], dostype[3]); + strlcat(state->pp_buf, tmp, PAGE_SIZE); + snprintf(tmp, sizeof(tmp), "(res %d spb %d)", + be32_to_cpu(pb->pb_Environment[6]), + be32_to_cpu(pb->pb_Environment[4])); + strlcat(state->pp_buf, tmp, PAGE_SIZE); + } + res = 1; + } + strlcat(state->pp_buf, "\n", PAGE_SIZE); + +rdb_done: + return res; +} |