partition.c

嵌入式linux（arm9）的平台下

#include "partition.h"
#include "example.h"

typedef struct Partition
{
	uint8	active;
	uint8	startingCHS[3];
	uint8	type;
	uint8	endingCHS[3];
	uint32	start;
	uint32	size;
} Partition;

typedef struct MBR
{
	uint8		bootInfo[446]		__attribute__ ((packed));	//byte align structure
	Partition	partitionTable[4]	__attribute__ ((packed));
	uint16		signature			__attribute__ ((packed));
} MBR;

int partitionIsType(enum PartitionType type, uint8 code)
{
	DPRINTF("type: %X, code: %X\n", type, code);
	//Type codes obtained from: http://www.win.tue.nl/~aeb/partitions/partition_types-1.html
	switch(type)
	{
	case FAT:	return
				code == 0x01 ||
				code == 0x04 ||
				code == 0x05 ||
				code == 0x06 ||
				code == 0x0B ||
				code == 0x0C ||
				code == 0x0E ||
				code == 0x11 ||
				code == 0x14 ||
				code == 0x16 ||
				code == 0x1B ||
				code == 0x1C ||
				code == 0x1E;
				break;
	case EXT2:	return 
				code == 0x82;
				break;
	}

	return 0;
}

int partitionGetRootSector(enum PartitionType type, int partitionNumber, DISK_READ_FUNCTION read)
{
	DPRINTF("type: %X, partition: %d\n", type, partitionNumber);
	MBR mbr;
	if(read(0, 1, &mbr))
		if(partitionIsType(type, mbr.partitionTable[partitionNumber].type))
			return mbr.partitionTable[partitionNumber].start;
	
	if (mbr.bootInfo[21] == 0xF8)	// SD doesn't have MBR; medium identifier (offset 0x21) should be 0xF8
		return 0;					// partition boot sector is in sector 0
	
	return -1;
}