| /* |
| * dosio.c -- Disk I/O module for the ext2fs/DOS library. |
| * |
| * Copyright (c) 1997 by Theodore Ts'o. |
| * |
| * Copyright (c) 1997 Mark Habersack |
| * |
| * %Begin-Header% |
| * This file may be redistributed under the terms of the GNU Library |
| * General Public License, version 2. |
| * %End-Header% |
| */ |
| |
| #include <stdio.h> |
| #include <bios.h> |
| #include <string.h> |
| #include <ctype.h> |
| #include <io.h> |
| #ifdef HAVE_ERRNO_H |
| #include <errno.h> |
| #endif |
| |
| #include <ext2fs/ext2_types.h> |
| #include "utils.h" |
| #include "dosio.h" |
| #include "et/com_err.h" |
| #include "ext2_err.h" |
| #include "ext2fs/io.h" |
| |
| /* |
| * Some helper macros |
| */ |
| #define LINUX_EXT2FS 0x83 |
| #define LINUX_SWAP 0x82 |
| #define WRITE_ERR(_msg_) write(2, _msg_, strlen(_msg_)) |
| #define WRITE_ERR_S(_msg_) write(2, _msg_, sizeof(_msg_)) |
| |
| /* |
| * Exported variables |
| */ |
| unsigned long _dio_error; |
| unsigned long _dio_hw_error; |
| |
| /* |
| * Array of all opened partitions |
| */ |
| static PARTITION **partitions = NULL; |
| static unsigned short npart = 0; /* Number of mapped partitions */ |
| static PARTITION *active = NULL; |
| |
| /* |
| * I/O Manager routine prototypes |
| */ |
| static errcode_t dos_open(const char *dev, int flags, io_channel *channel); |
| static errcode_t dos_close(io_channel channel); |
| static errcode_t dos_set_blksize(io_channel channel, int blksize); |
| static errcode_t dos_read_blk(io_channel channel, unsigned long block, |
| int count, void *buf); |
| static errcode_t dos_write_blk(io_channel channel, unsigned long block, |
| int count, const void *buf); |
| static errcode_t dos_flush(io_channel channel); |
| |
| static struct struct_io_manager struct_dos_manager = { |
| EXT2_ET_MAGIC_IO_MANAGER, |
| "DOS I/O Manager", |
| dos_open, |
| dos_close, |
| dos_set_blksize, |
| dos_read_blk, |
| dos_write_blk, |
| dos_flush |
| }; |
| io_manager dos_io_manager = &struct_dos_manager; |
| |
| /* |
| * Macro taken from unix_io.c |
| */ |
| /* |
| * For checking structure magic numbers... |
| */ |
| |
| #define EXT2_CHECK_MAGIC(struct, code) \ |
| if ((struct)->magic != (code)) return (code) |
| |
| /* |
| * Calculates a CHS address of a sector from its LBA |
| * offset for the given partition. |
| */ |
| static void lba2chs(unsigned long lba_addr, CHS *chs, PARTITION *part) |
| { |
| unsigned long abss; |
| |
| chs->offset = lba_addr & 0x000001FF; |
| abss = (lba_addr >> 9) + part->start; |
| chs->cyl = abss / (part->sects * part->heads); |
| chs->head = (abss / part->sects) % part->heads; |
| chs->sector = (abss % part->sects) + 1; |
| } |
| |
| #ifdef __TURBOC__ |
| #pragma argsused |
| #endif |
| /* |
| * Scans the passed partition table looking for *pno partition |
| * that has LINUX_EXT2FS type. |
| * |
| * TODO: |
| * For partition numbers >5 Linux uses DOS extended partitions - |
| * dive into them an return an appropriate entry. Also dive into |
| * extended partitions when scanning for a first Linux/ext2fs. |
| */ |
| static PTABLE_ENTRY *scan_partition_table(PTABLE_ENTRY *pentry, |
| unsigned short phys, |
| unsigned char *pno) |
| { |
| unsigned i; |
| |
| if(*pno != 0xFF && *pno >= 5) |
| return NULL; /* We don't support extended partitions for now */ |
| |
| if(*pno != 0xFF) |
| { |
| if(pentry[*pno].type == LINUX_EXT2FS) |
| return &pentry[*pno]; |
| else |
| { |
| if(!pentry[*pno].type) |
| *pno = 0xFE; |
| else if(pentry[*pno].type == LINUX_SWAP) |
| *pno = 0xFD; |
| return NULL; |
| } |
| } |
| |
| for(i = 0; i < 4; i++) |
| if(pentry[i].type == LINUX_EXT2FS) |
| { |
| *pno = i; |
| return &pentry[i]; |
| } |
| |
| return NULL; |
| } |
| |
| /* |
| * Allocate libext2fs structures associated with I/O manager |
| */ |
| static io_channel alloc_io_channel(PARTITION *part) |
| { |
| io_channel ioch; |
| |
| ioch = (io_channel)malloc(sizeof(struct struct_io_channel)); |
| if (!ioch) |
| return NULL; |
| memset(ioch, 0, sizeof(struct struct_io_channel)); |
| ioch->magic = EXT2_ET_MAGIC_IO_CHANNEL; |
| ioch->manager = dos_io_manager; |
| ioch->name = (char *)malloc(strlen(part->dev)+1); |
| if (!ioch->name) { |
| free(ioch); |
| return NULL; |
| } |
| strcpy(ioch->name, part->dev); |
| ioch->private_data = part; |
| ioch->block_size = 1024; /* The smallest ext2fs block size */ |
| ioch->read_error = 0; |
| ioch->write_error = 0; |
| |
| return ioch; |
| } |
| |
| #ifdef __TURBOC__ |
| #pragma argsused |
| #endif |
| /* |
| * Open the 'name' partition, initialize all information structures |
| * we need to keep and create libext2fs I/O manager. |
| */ |
| static errcode_t dos_open(const char *dev, int flags, io_channel *channel) |
| { |
| unsigned char *tmp, sec[512]; |
| PARTITION *part; |
| PTABLE_ENTRY *pent; |
| PARTITION **newparts; |
| |
| if(!dev) |
| { |
| _dio_error = ERR_BADDEV; |
| return EXT2_ET_BAD_DEVICE_NAME; |
| } |
| |
| /* |
| * First check whether the dev name is OK |
| */ |
| tmp = (unsigned char*)strrchr(dev, '/'); |
| if(!tmp) |
| { |
| _dio_error = ERR_BADDEV; |
| return EXT2_ET_BAD_DEVICE_NAME; |
| } |
| *tmp = 0; |
| if(strcmp(dev, "/dev")) |
| { |
| _dio_error = ERR_BADDEV; |
| return EXT2_ET_BAD_DEVICE_NAME; |
| } |
| *tmp++ = '/'; |
| |
| /* |
| * Check whether the partition data is already in cache |
| */ |
| |
| part = (PARTITION*)malloc(sizeof(PARTITION)); |
| if (!part) |
| return ENOMEM; |
| { |
| int i = 0; |
| |
| for(;i < npart; i++) |
| if(!strcmp(partitions[i]->dev, dev)) |
| { |
| /* Found it! Make it the active one */ |
| active = partitions[i]; |
| *channel = alloc_io_channel(active); |
| if (!*channel) |
| return ENOMEM; |
| return 0; |
| } |
| } |
| |
| /* |
| * Drive number & optionally partn number |
| */ |
| switch(tmp[0]) |
| { |
| case 'h': |
| case 's': |
| part->phys = 0x80; |
| part->phys += toupper(tmp[2]) - 'A'; |
| /* |
| * Do we have the partition number? |
| */ |
| if(tmp[3]) |
| part->pno = isdigit((int)tmp[3]) ? tmp[3] - '0' - 1: 0; |
| else |
| part->pno = 0xFF; |
| break; |
| |
| case 'f': |
| if(tmp[2]) |
| part->phys = isdigit((int)tmp[2]) ? tmp[2] - '0' : 0; |
| else |
| part->phys = 0x00; /* We'll assume /dev/fd0 */ |
| break; |
| |
| default: |
| _dio_error = ERR_BADDEV; |
| return ENODEV; |
| } |
| |
| if(part->phys < 0x80) |
| { |
| /* We don't support floppies for now */ |
| _dio_error = ERR_NOTSUPP; |
| return EINVAL; |
| } |
| |
| part->dev = strdup(dev); |
| |
| /* |
| * Get drive's geometry |
| */ |
| _dio_hw_error = biosdisk(DISK_GET_GEOMETRY, |
| part->phys, |
| 0, /* head */ |
| 0, /* cylinder */ |
| 1, /* sector */ |
| 1, /* just one sector */ |
| sec); |
| |
| if(!HW_OK()) |
| { |
| _dio_error = ERR_HARDWARE; |
| free(part->dev); |
| free(part); |
| return EFAULT; |
| } |
| |
| /* |
| * Calculate the geometry |
| */ |
| part->cyls = (unsigned short)(((sec[0] >> 6) << 8) + sec[1] + 1); |
| part->heads = sec[3] + 1; |
| part->sects = sec[0] & 0x3F; |
| |
| /* |
| * Now that we know all we need, let's look for the partition |
| */ |
| _dio_hw_error = biosdisk(DISK_READ, part->phys, 0, 0, 1, 1, sec); |
| |
| if(!HW_OK()) |
| { |
| _dio_error = ERR_HARDWARE; |
| free(part->dev); |
| free(part); |
| return EFAULT; |
| } |
| |
| pent = (PTABLE_ENTRY*)&sec[0x1BE]; |
| pent = scan_partition_table(pent, part->phys, &part->pno); |
| |
| if(!pent) |
| { |
| _dio_error = part->pno == 0xFE ? ERR_EMPTYPART : |
| part->pno == 0xFD ? ERR_LINUXSWAP : ERR_NOTEXT2FS; |
| free(part->dev); |
| free(part); |
| return ENODEV; |
| } |
| |
| /* |
| * Calculate the remaining figures |
| */ |
| { |
| unsigned long fsec, fhead, fcyl; |
| |
| fsec = (unsigned long)(pent->start_sec & 0x3F); |
| fhead = (unsigned long)pent->start_head; |
| fcyl = ((pent->start_sec >> 6) << 8) + pent->start_cyl; |
| part->start = fsec + fhead * part->sects + fcyl * |
| (part->heads * part->sects) - 1; |
| part->len = pent->size; |
| } |
| |
| /* |
| * Add the partition to the table |
| */ |
| newparts = (PARTITION**)realloc(partitions, sizeof(PARTITION) * npart); |
| if (!newparts) { |
| free(part); |
| return ENOMEM; |
| } |
| partitions = newparts; |
| partitions[npart++] = active = part; |
| |
| /* |
| * Now alloc all libe2fs structures |
| */ |
| *channel = alloc_io_channel(active); |
| if (!*channel) |
| return ENOMEM; |
| |
| return 0; |
| } |
| |
| static errcode_t dos_close(io_channel channel) |
| { |
| free(channel->name); |
| free(channel); |
| |
| return 0; |
| } |
| |
| static errcode_t dos_set_blksize(io_channel channel, int blksize) |
| { |
| channel->block_size = blksize; |
| |
| return 0; |
| } |
| |
| static errcode_t dos_read_blk(io_channel channel, unsigned long block, |
| int count, void *buf) |
| { |
| PARTITION *part; |
| size_t size; |
| ext2_loff_t loc; |
| CHS chs; |
| |
| EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); |
| part = (PARTITION*)channel->private_data; |
| |
| size = (size_t)((count < 0) ? -count : count * channel->block_size); |
| loc = (ext2_loff_t) block * channel->block_size; |
| |
| lba2chs(loc, &chs, part); |
| /* |
| * Potential bug here: |
| * If DJGPP is used then reads of >18 sectors will fail! |
| * Have to rewrite biosdisk. |
| */ |
| _dio_hw_error = biosdisk(DISK_READ, |
| part->phys, |
| chs.head, |
| chs.cyl, |
| chs.sector, |
| size < 512 ? 1 : size/512, |
| buf); |
| |
| if(!HW_OK()) |
| { |
| _dio_error = ERR_HARDWARE; |
| return EFAULT; |
| } |
| |
| return 0; |
| } |
| |
| static errcode_t dos_write_blk(io_channel channel, unsigned long block, |
| int count, const void *buf) |
| { |
| PARTITION *part; |
| size_t size; |
| ext2_loff_t loc; |
| CHS chs; |
| |
| EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); |
| part = (PARTITION*)channel->private_data; |
| |
| if(count == 1) |
| size = (size_t)channel->block_size; |
| else |
| { |
| if (count < 0) |
| size = (size_t)-count; |
| else |
| size = (size_t)(count * channel->block_size); |
| } |
| |
| loc = (ext2_loff_t)block * channel->block_size; |
| lba2chs(loc, &chs, part); |
| _dio_hw_error = biosdisk(DISK_WRITE, |
| part->phys, |
| chs.head, |
| chs.cyl, |
| chs.sector, |
| size < 512 ? 1 : size/512, |
| (void*)buf); |
| |
| if(!HW_OK()) |
| { |
| _dio_error = ERR_HARDWARE; |
| return EFAULT; |
| } |
| |
| return 0; |
| } |
| |
| #ifdef __TURBOC__ |
| #pragma argsused |
| #endif |
| static errcode_t dos_flush(io_channel channel) |
| { |
| /* |
| * No buffers, no flush... |
| */ |
| return 0; |
| } |
