💾 Archived View for mirrors.apple2.org.za › archive › ground.icaen.uiowa.edu › MiscInfo › Programmin… captured on 2023-01-29 at 10:17:27.
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"Sheldon Simms" <sheldon@interprice.com> writes:
>Speaking of which, I'd love to get a doc of the ProDOS filesystem. I own
>the ProDOS reference manual but it's inaccessible to me at the moment
>(and I don't imagine I'll be able to get it back until the end of the
>year). I managed to reverse engineer pretty much everything by poking
>around a disk image with a hex editor and relying on memory, but I'd like
>to see a doc before December just be to sure I got it right.
I have the ProDOS Technical Reference manual (1st & 2nd editions) as well
as Beneath Apple ProDOS which all document the filesystem format. Here is
some code that can read a ProDOS filesystem (except for Tree files) to
let you cross check your code.
prodos.h:
/*
* Directory pointers
*/
#define Prev(x) (x[0] + (x[1] << 8))
#define Next(x) (x[2] + (x[3] << 8))
/*
* Fields common to vol header, sub dir headers & file entries
*/
#define Storage_type(x) (x[0] >> 4)
#define Name_length(x) (x[0] & 15)
#define Active(x) (x[0] != 0)
#define File_name(x) (x + 1)
#define Creation(x) (x[0x1a] + (x[0x1b] << 8) + (x[0x18] << 16) + (x[0x19] << 24))
#define Version(x) (x[0x1c])
#define Min_version(x) (x[0x1d])
#define Access(x) (x[0x1e])
/*
* File entry only
*/
#define File_type(x) (x[0x10])
#define Key_pointer(x) (x[0x11] + (x[0x12] << 8))
#define Blocks_used(x) (x[0x13] + (x[0x14] << 8))
#define Eof(x) (x[0x15] + (x[0x16] << 8) + (x[0x17] << 16))
#define Aux_type(x) (x[0x1f] + (x[0x20] << 8))
#define Last_mod(x) (x[0x23] + (x[0x24] << 8) + (x[0x21] << 16) + (x[0x22] << 24))
#define Header_pointer(x) (x[0x25] + (x[0x26] << 8))
/*
* Vol & sub dir headers
*/
#define Entry_length(x) (x[0x1f])
#define Entries_per_block(x) (x[0x20])
#define File_count(x) (x[0x21] + (x[0x22] << 8))
/*
* Vol header only
*/
#define Bit_map_pointer(x) (x[0x23] + (x[0x24] << 8))
#define Total_blocks(x) (x[0x25] + (x[0x26] << 8))
/*
* Sub dir header only
*/
#define Parent_entry_number(x) (x[0x25])
#define Parent_entry_length(x) (x[0x26])
#define Parent_pointer(x) (x[0x23] + (x[0x24] << 8))
/*
* Date format
*/
#define year(x) ((x >> 25) & 127)
#define month(x) ((x >> 21) & 15)
#define day(x) ((x >> 16) & 31)
#define hour(x) ((x >> 8) & 31)
#define minute(x) (x & 63)
/*
* Indirect block function
*/
#define indirect(block,index) (block[index] + (block[index + 256] << 8))
/*
* ProDOS constants
*/
#define PRODOS_BS 512
#define PRODOS_ROOT 2
protar.c:
#include <stdio.h>
#include <fcntl.h>
#include "prodos.h"
extern long lseek();
extern char *sprintf();
char err[80], filename[64];
main(argc, argv)
int argc;
char *argv[];
{
ReadDir(PRODOS_ROOT, 0);
}
ReadDir(blocknum, filelen)
unsigned blocknum, filelen;
{
unsigned char block[PRODOS_BS];
int elen, epb, fc, be, ae;
unsigned char *ep;
if (lseek(0, (long) (PRODOS_BS * blocknum), 0) == -1L ||
read(0, (char *) block, PRODOS_BS) == -1)
{
sprintf(err, "Error reading block %d", blocknum);
perror(err);
return;
}
ep = block + 4;
if (filelen == 0)
{
sprintf(filename, "%.*s", Name_length(ep), File_name(ep));
filelen = Name_length(ep);
}
elen = Entry_length(ep);
epb = Entries_per_block(ep);
fc = File_count(ep);
ep += elen;
be = 2;
ae = 0;
while (ae < fc)
{
if (Active(ep))
{
ProcessEntry(ep, filelen);
++ae;
}
if (ae < fc)
if (be == epb)
{
if (Next(block) == 0)
{
fprintf(stderr, "Short Directory. ae = %d fc = %d blocknum = %d\n", ae, fc, blocknum);
return;
}
blocknum = Next(block);
if (lseek(0, (long) (PRODOS_BS * blocknum), 0) == -1L ||
read(0, (char *) block, PRODOS_BS) == -1)
{
sprintf(err, "Error reading block %d", blocknum);
perror(err);
return;
}
be = 1;
ep = block + 4;
}
else
{
ep += elen;
++be;
}
}
}
ProcessEntry(ep, filelen)
unsigned char *ep;
unsigned filelen;
{
sprintf(filename + filelen, "/%.*s", Name_length(ep), File_name(ep));
filelen += Name_length(ep) + 1;
ProcessFile(ep);
if (File_type(ep) == 0x0f)
ReadDir(Key_pointer(ep), filelen);
filelen -= Name_length(ep) + 1;
}
unsigned char masterblock[PRODOS_BS], ptrblock[PRODOS_BS], datablock[PRODOS_BS];
ProcessFile(ep)
unsigned char *ep;
{
int fd, len, i;
#ifdef DEBUG
puts(filename);
#else
switch (Storage_type(ep))
{
case 0: /* Inactive */
break;
case 1: /* Seedling */
if ((fd = open(filename, O_WRONLY|O_CREAT, 0777)) < 0)
perror(filename);
else
{
len = Eof(ep);
if (lseek(0, (long) (PRODOS_BS * Key_pointer(ep)), 0) == -1L ||
read(0, datablock, len) != len ||
write(fd, datablock, len) != len ||
close(fd) == -1)
perror(filename);
}
break;
case 2: /* Sapling */
if ((fd = open(filename, O_WRONLY|O_CREAT, 0777)) < 0)
perror(filename);
else
{
len = Eof(ep);
if (lseek(0, (long) (PRODOS_BS * Key_pointer(ep)), 0) == -1L ||
read(0, ptrblock, PRODOS_BS) != PRODOS_BS)
perror(filename);
else
{
for (i = 0; len >= PRODOS_BS; ++i, len -= PRODOS_BS)
if (lseek(0, (long) PRODOS_BS * indirect(ptrblock, i), 0) == -1L ||
read(0, datablock, PRODOS_BS) != PRODOS_BS ||
write(fd, datablock, PRODOS_BS) != PRODOS_BS)
perror(filename);
if (len)
if (lseek(0, (long) PRODOS_BS * indirect(ptrblock, i), 0) == -1L ||
read(0, datablock, len) != len ||
write(fd, datablock, len) != len)
perror(filename);
if (close(fd) == -1)
perror(filename);
}
}
break;
case 3: /* Tree */
break;
case 0xd: /* SubDir file entry */
if (mkdir(filename, 0777) == -1)
perror(filename);
break;
case 0xe: /* SubDir header */
break;
case 0xf: /* Vol header */
break;
default: /* ??? */
fprintf(stderr, "%s: unknown storage_type %x\n", filename, Storage_type(ep));
break;
}
#endif
}
--
David Wilson School of IT & CS, Uni of Wollongong, Australia