131 lines
3.2 KiB
C
131 lines
3.2 KiB
C
#include "fs.h"
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#include "disk.h"
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struct FsType {
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uint32_t type_id;
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int (*init_func)(filesystem *, uint32_t);
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// Not yet decided
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char (*detect_func)(uint32_t);
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};
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// TODO Get these dynamically somehow
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int InitDosFs(filesystem *fs, uint32_t start_sector);
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char DetectDosPart(uint32_t start_sector);
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struct FsType SupportedFilesystems[] = {
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{
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.type_id = 0xD05,
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.init_func = InitDosFs,
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.detect_func = DetectDosPart
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}
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};
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#define MAXFS 255
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filesystem *ActiveFilesystems = (filesystem *)0x240000;
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uint8_t ActiveFsIdx;
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filesystem *GetFilesystem(uint8_t idx) {
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if (idx >= MAXFS) return 0;
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filesystem *fs = &ActiveFilesystems[idx];
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return fs->type != 0 ? fs : 0;
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}
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filesystem *GetActiveFilesystem() {
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return &ActiveFilesystems[ActiveFsIdx];
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}
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uint8_t GetActiveFilesystemId() {
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return ActiveFsIdx;
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}
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filesystem *SetActiveFilesystem(uint8_t idx) {
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if (idx >= MAXFS) return 0;
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filesystem *fs = &ActiveFilesystems[idx];
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if (fs->type == 0) return 0;
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ActiveFsIdx = idx;
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return fs;
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}
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void ActiveFilesystemBitmap(char *bitmap) {
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for (int i = 0; i < 256; i++)
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bitmap[i] = ActiveFilesystems[i].type != 0;
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}
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struct PartTableEntry_t {
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uint8_t attr;
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uint8_t start_chs0;
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uint8_t start_chs1;
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uint8_t start_chs2;
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uint8_t type;
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uint8_t end_chs0;
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uint8_t end_chs1;
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uint8_t end_chs2;
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uint32_t start_lba;
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uint32_t num_sectors;
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};
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typedef struct MBR_t {
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char boot_code[0x1B8];
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uint32_t signature;
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uint16_t reserved;
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struct PartTableEntry_t partTable[4];
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uint16_t boot_sig;
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} __attribute__((__packed__)) MBR_t;
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// TODO Just check for this
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uint8_t BootPartition;
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uint8_t NextAvailableFilesystem;
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MBR_t SysMbr;
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void MakeMBRPartitions() {
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// Get MBR
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MBR_t *mbr = &SysMbr;
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Disk_ReadSector(0, (uint8_t*)mbr, 0, 1);
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// Scan partitions
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for (int p = 0; p < 4; p++) {
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if (p == BootPartition) continue;
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if (mbr->partTable[p].type == 0) continue;
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uint32_t partStart = mbr->partTable[p].start_lba;
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if (partStart == 0) continue;
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// Scan supported filesystems
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filesystem *sys = &ActiveFilesystems[NextAvailableFilesystem];
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for (int i = 0; i < sizeof(SupportedFilesystems)/sizeof(struct FsType); i++) {
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if (!SupportedFilesystems[i].detect_func(partStart)) continue;
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SupportedFilesystems[i].init_func(sys, partStart);
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sys->type = SupportedFilesystems[i].type_id;
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ActiveFsIdx = NextAvailableFilesystem;
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NextAvailableFilesystem++;
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break;
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}
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}
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}
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int MakeSystemVolume(uint8_t bootPartition) {
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// Clear out filesystem area
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for (int i = 0; i < (sizeof(filesystem)*MAXFS)/sizeof(uint32_t);i++)
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((uint32_t*)ActiveFilesystems)[i] = 0;
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BootPartition = bootPartition;
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NextAvailableFilesystem = 1;
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// Get MBR
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MBR_t *mbr = &SysMbr;
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Disk_ReadSector(0, (uint8_t*)mbr, 0, 1);
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// Get boot partition sector
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uint32_t sys_sector = mbr->partTable[bootPartition].start_lba;
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// Scan supported filesystems
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filesystem *sys = &ActiveFilesystems[0];
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for (int i = 0; i < sizeof(SupportedFilesystems)/sizeof(struct FsType); i++) {
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asm volatile("xchg %bx,%bx");
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if (!SupportedFilesystems[i].detect_func(sys_sector)) continue;
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SupportedFilesystems[i].init_func(sys, sys_sector);
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sys->type = SupportedFilesystems[i].type_id;
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ActiveFsIdx = 0;
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return 0;
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}
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// Init Failed
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return -1;
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}
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