| Yi Kong | 39bbd96 | 2022-01-09 19:41:38 +0800 | [diff] [blame] | 1 | /* Copyright 2021 Alain Knaff. |
| 2 | * This file is part of mtools. |
| 3 | * |
| 4 | * Mtools is free software: you can redistribute it and/or modify |
| 5 | * it under the terms of the GNU General Public License as published by |
| 6 | * the Free Software Foundation, either version 3 of the License, or |
| 7 | * (at your option) any later version. |
| 8 | * |
| 9 | * Mtools is distributed in the hope that it will be useful, |
| 10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 12 | * GNU General Public License for more details. |
| 13 | * |
| 14 | * You should have received a copy of the GNU General Public License |
| 15 | * along with Mtools. If not, see <http://www.gnu.org/licenses/>. |
| 16 | */ |
| 17 | |
| 18 | #include "sysincludes.h" |
| 19 | #include "llong.h" |
| 20 | #include "device.h" |
| 21 | |
| 22 | int check_if_sectors_fit(uint32_t tot_sectors, |
| 23 | mt_off_t maxBytes, |
| 24 | uint32_t sectorSize, |
| 25 | char *errmsg) |
| 26 | { |
| 27 | if(!maxBytes) |
| 28 | return 0; /* Maxbytes = 0 => no checking */ |
| 29 | if(tot_sectors > (smt_off_t) maxBytes / (smt_off_t) sectorSize) { |
| 30 | sprintf(errmsg, |
| 31 | "%d sectors too large for this platform\n", |
| 32 | tot_sectors); |
| 33 | return -1; |
| 34 | } |
| 35 | return 0; |
| 36 | } |
| 37 | |
| 38 | /* |
| 39 | * Calculate number of total sectors on device if needed, and check that |
| 40 | * they fit into |
| 41 | */ |
| 42 | int chs_to_totsectors(struct device *dev, char *errmsg) |
| 43 | { |
| 44 | uint32_t sect_per_track, tot_sectors; |
| 45 | |
| 46 | if(dev->tot_sectors) |
| 47 | return 0; |
| 48 | |
| 49 | if(!dev->heads || !dev->sectors || !dev->tracks) |
| 50 | return 0; /* not fully specified => we cannot do |
| 51 | anything anyways */ |
| 52 | |
| 53 | /* Cannot overflow as both dev->heads and dev->sectors are 16 |
| 54 | * bit quantities, whose product will be put into a 32 bit |
| 55 | * field */ |
| 56 | sect_per_track = dev->heads * dev->sectors; |
| 57 | |
| 58 | if(dev->tracks > UINT32_MAX / sect_per_track) { |
| 59 | /* Would not fit in 32 bits */ |
| 60 | |
| 61 | if(errmsg) |
| 62 | sprintf(errmsg, |
| 63 | "Number of sectors larger than 2^32\n"); |
| 64 | return -1; |
| 65 | } |
| 66 | |
| 67 | tot_sectors = dev->tracks * sect_per_track; |
| 68 | if(tot_sectors > dev->hidden % sect_per_track) |
| 69 | tot_sectors -= dev->hidden % sect_per_track; |
| 70 | dev->tot_sectors = tot_sectors; |
| 71 | return 0; |
| 72 | } |