92 lines
2.1 KiB
C
92 lines
2.1 KiB
C
// vfs.c
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// Author: Josh Holtrop
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// Created: 12/31/03
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// Modified: 01/04/04
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void vfs_init()
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{
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firstDiskDevice = malloc(sizeof(DiskDevice));
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firstDiskDevice->type = VFS_DISK_FD;
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firstDiskDevice->fileSystem = VFS_FS_FAT12;
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firstDiskDevice->location = VFS_LOC_FD0;
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firstDiskDevice->link = 0;
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strcpy(firstDiskDevice->id, "fd0");
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rootDevice = firstDiskDevice;
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if (*(byte *)0xC0090000) // the user chose to load an initial ram disk from the floppy
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{
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DiskDevice *rd = malloc(sizeof(DiskDevice));
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firstDiskDevice->link = (dword)rd;
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rd->type = VFS_DISK_RD;
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rd->fileSystem = VFS_FS_FAT12;
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rd->location = 0xC0200000;
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rd->link = 0;
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strcpy(rd->id, "rd0");
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rootDevice = rd;
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}
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}
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byte *vfs_readFile(char *fileName)
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{
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DiskDevice *dd;
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dword fileStartPosition;
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if (fileName[0] == '/')
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{
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dd = rootDevice;
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fileStartPosition = 1;
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}
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else
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{
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if (strlen(fileName) < 5) //not a long enough file name
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return 0;
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if (!((fileName[3] == ':') && (fileName[4] == '/'))) //if we aren't using the root directory, then there must be a 3 character device explicitly specified
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return 0; // followed by a colon and then a slash
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char device[4];
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memcpy(device, fileName, 3); //copy the 3 digit device id to device
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device[3] = 0; //null-terminating character for device string
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dd = vfs_getDiskDeviceByID(device);
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if (!dd) //the specified device was not found
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return 0;
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fileStartPosition = 5;
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}
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switch (dd->fileSystem)
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{
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case VFS_FS_FAT12:
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return fat12_readFile(fileName+fileStartPosition, dd);
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}
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return 0;
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}
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byte *vfs_readSector(DiskDevice *dd, dword sector, byte *dest, dword sectors)
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{
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byte *origDest = dest;
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switch (dd->type)
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{
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case VFS_DISK_RD:
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for (; sectors > 0; sectors--, dest += 512, sector++)
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rd_readSector(dd, sector, dest);
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return origDest;
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}
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return 0;
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}
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DiskDevice *vfs_getDiskDeviceByID(char *id)
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{
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DiskDevice *dd = firstDiskDevice;
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for (;;)
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{
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if (strcmp(dd->id, id))
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return dd;
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dd = (DiskDevice *)dd->link;
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if (!dd)
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break;
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}
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return 0;
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}
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