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-rw-r--r--lib/ext2fs/dosio.c459
1 files changed, 459 insertions, 0 deletions
diff --git a/lib/ext2fs/dosio.c b/lib/ext2fs/dosio.c
new file mode 100644
index 0000000..d0cf269
--- /dev/null
+++ b/lib/ext2fs/dosio.c
@@ -0,0 +1,459 @@
+/*
+ * 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 "config.h"
+#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 = {
+ .magic = EXT2_ET_MAGIC_IO_MANAGER,
+ .name = "DOS I/O Manager",
+ .open = dos_open,
+ .close = dos_close,
+ .set_blksize = dos_set_blksize,
+ .read_blk = dos_read_blk,
+ .write_blk = dos_write_blk,
+ .flush = 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;
+}
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