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-rw-r--r--libc/bios/fs_dos.c421
1 files changed, 421 insertions, 0 deletions
diff --git a/libc/bios/fs_dos.c b/libc/bios/fs_dos.c
new file mode 100644
index 0000000..28ee962
--- /dev/null
+++ b/libc/bios/fs_dos.c
@@ -0,0 +1,421 @@
+
+#include <stdio.h>
+#include <ctype.h>
+#include <malloc.h>
+#include <errno.h>
+#include "io.h"
+#include "rawio.h"
+
+#define DONT_BUFFER_FAT
+
+#define DOS_SECT(P) get_uint(P,0x0B)
+#define DOS_CLUST(P) get_byte(P,0x0D)
+#define DOS_RESV(P) get_uint(P,0x0E)
+#define DOS_NFAT(P) get_byte(P,0x10)
+#define DOS_NROOT(P) get_uint(P,0x11)
+#define DOS_MAXSECT(P) get_uint(P,0x13)
+#define DOS_MEDIA(P) get_byte(P,0x15)
+#define DOS_FATLEN(P) get_uint(P,0x16)
+#define DOS_SPT(P) get_uint(P,0x18)
+#define DOS_HEADS(P) get_uint(P,0x1A)
+#define DOS_HIDDEN(P) get_long(P,0x1C)
+#define DOS4_MAXSECT(P) get_long(P,0x20)
+#define DOS4_PHY_DRIVE(P) get_byte(P,0x24)
+#define DOS4_SERIAL(P) get_long(P,0x27)
+
+/* These assume alignment is not a problem */
+#define get_byte(P,Off) *((unsigned char*)((char*)(P)+(Off)))
+#define get_uint(P,Off) *((unsigned short*)((char*)(P)+(Off)))
+#define get_long(P,Off) *((long*)((char*)(P)+(Off)))
+
+static int read_bootblock();
+static int dir_nentry, dir_sect;
+static int dos_clust0, dos_spc, dos_fatpos;
+static int last_serial = 0;
+
+#ifdef BUFFER_FAT
+static char * fat_buf = 0;
+#endif
+
+struct filestatus {
+ char fname[12];
+ unsigned short first_cluster;
+ unsigned short cur_cluster;
+ unsigned short sector_no;
+ long file_length;
+};
+
+static int fsdos_read_block();
+static int fsdos_close_file();
+
+/* buffer to read into */
+static char sect[512];
+
+fsdos_open_file(iob, fname, flags, mode)
+ioblock* iob;
+char * fname;
+int flags;
+int mode;
+{
+ extern union REGS __argr;
+ char conv_name[12];
+ char *d, *s;
+ int i;
+ int dodir = 0;
+ struct filestatus* cur_file;
+
+#ifdef DEBUG
+ printf("fsdos_open_file(%x, %s, %d, %d, %d)\n",
+ iob, fname, flags, mode, sizeof(iob));
+#endif
+ iob->block_read = fsdos_read_block;
+ iob->close = fsdos_close_file;
+
+ /* Get the superblock */
+ if( read_bootblock() < 0 ) return -1;
+
+ if(strcmp(fname, ".") == 0)
+ dodir = 1;
+ else
+ {
+ /* Convert the name to MSDOS directory format */
+ strcpy(conv_name, " ");
+ for(s=fname, d=conv_name; *s && *d && *s != '.' && *s != ' '; s++)
+ {
+ if( islower(*s) ) *d++ = toupper(*s);
+ else *d++ = *s;
+ }
+ while( *s && *s != '.' ) s++;
+ strcpy(d=(conv_name+8), " ");
+ if( *s == '.' )
+ {
+ for(s++; *s && *d; s++)
+ {
+ if( islower(*s) ) *d++ = toupper(*s);
+ else *d++ = *s;
+ }
+ }
+ }
+#ifdef DEBUG
+ printf("fsdos_open_file: converted filename=<%s>\n", conv_name);
+#endif
+
+#ifdef BUFFER_FAT
+ rawio_read_sector(0, sect);
+
+ if( !dodir )
+ {
+ /* Read in and buffer the FAT */
+ if( fat_buf ) free(fat_buf);
+ fat_buf = malloc(DOS_FATLEN(sect) * 512);
+ if( fat_buf == 0 )
+ {
+ errno = ENOMEM;
+ return -1;
+ }
+ else
+ {
+ int fatsec = DOS_RESV(sect);
+ int nsec = DOS_FATLEN(sect);
+
+ for(i=0; i<nsec; i++)
+ {
+ if (rawio_read_sector(fatsec+i, sect) == 0)
+ {
+ errno = EIO;
+ return -1;
+ }
+ memcpy(fat_buf+i*512, sect, 512);
+ }
+ }
+ }
+#endif
+
+ /* Scan the root directory for the file */
+ s = sect;
+ for(i=0; i<dir_nentry; i++)
+ {
+ if (rawio_read_sector(dir_sect+i/16, sect) == 0)
+ {
+ errno = EIO;
+ return -1;
+ }
+ d = s + (i%16)*32;
+ if( dodir )
+ {
+ char dtime[20];
+ char lbuf[90];
+ *lbuf = 0;
+
+ sprintf(dtime, " %02d/%02d/%04d %02d:%02d",
+ (get_uint(d,24)&0x1F),
+ ((get_uint(d,24)>>5)&0xF),
+ ((get_uint(d,24)>>9)&0x7F)+1980,
+ ((get_uint(d,22)>>11)&0x1F),
+ ((get_uint(d,22)>>5)&0x3F)
+ );
+ if( *d > ' ' && *d <= '~' ) switch(d[11]&0x18)
+ {
+ case 0:
+ printf("%-8.8s %-3.3s %10ld%s\n", d, d+8, get_long(d,28), dtime);
+ break;
+ case 0x10:
+ printf("%-8.8s %-3.3s <DIR> %s\n", d, d+8, dtime);
+ break;
+ case 8:
+ if( (d[11] & 7) == 0 )
+ printf("%-11.11s <LBL> %s\n", d, dtime);
+ break;
+ }
+#if 0
+ if( more_strn(lbuf, sizeof(lbuf)) < 0 ) break;
+#endif
+ }
+ else if( memcmp(d, conv_name, 11) == 0 && (d[11]&0x18) == 0 )
+ { /* Name matches and is normal file */
+
+#ifdef DEBUG
+ fprintf(stderr, "dos_open_file: %s worked\n", fname);
+#endif
+ cur_file = malloc(sizeof(*cur_file));
+
+ iob->context = cur_file;
+ if (iob->context == NULL)
+ {
+ errno = ENOMEM;
+ return -1;
+ }
+ memset(cur_file, '\0', sizeof(*cur_file));
+ strcpy(cur_file->fname, conv_name);
+ cur_file->first_cluster = get_uint(d,26);
+ cur_file->file_length = get_long(d,28);
+
+ cur_file->cur_cluster = cur_file->first_cluster;
+ cur_file->sector_no = 0;
+
+ return 0;
+ }
+ }
+ return -1;
+}
+
+fsdos_rewind_file(iob)
+ioblock* iob;
+{
+ struct filestatus* cur_file;
+
+ if (iob == NULL || iob->context == NULL)
+ {
+ errno = EBADF;
+ return -1;
+ }
+
+ cur_file = (struct filestatus*) iob->context;
+ /* Is there an opened file ? */
+ if( cur_file->fname[0] == 0 ) return -1;
+
+ cur_file->sector_no = 0;
+ cur_file->cur_cluster = cur_file->first_cluster;
+ return 0;
+}
+
+static int fsdos_close_file(iob)
+ioblock* iob;
+{
+ struct filestatus* cur_file;
+
+ if (iob == NULL || iob->context == NULL)
+ {
+ errno = EBADF;
+ return -1;
+ }
+ cur_file = (struct filestatus*) iob->context;
+ free(cur_file);
+ iob->context = NULL;
+
+#ifdef BUFFER_FAT
+ if( fat_buf ) free(fat_buf);
+ fat_buf = 0;
+#endif
+
+ rawio_reset_disk();
+ return 0;
+}
+
+long
+fsdos_file_length(iob)
+ioblock* iob;
+{
+ struct filestatus* cur_file;
+
+ if (iob == NULL || iob->context == NULL)
+ {
+ errno = EBADF;
+ return -1;
+ }
+ cur_file = (struct filestatus*) iob->context;
+
+ /* Is there an opened file ? */
+ if( cur_file->fname[0] == 0 ) return -1;
+
+ return cur_file->file_length;
+}
+
+static int fsdos_read_block(iob, buffer, block)
+ioblock* iob;
+char * buffer;
+long block; /* ignored for now */
+{
+ int s;
+ char * ptr = buffer;
+ struct filestatus* cur_file;
+ long amount_left_in_file;
+ long amount_to_read;
+
+#ifdef DEBUG
+ fprintf(stderr, "rb: iob = %x, buf = %x, block = %ld\n",
+ iob, buffer, block);
+#endif
+ if (iob == NULL || iob->context == NULL)
+ {
+ fprintf(stderr, "rb: no context\n");
+ errno = EBADF;
+ return -1;
+ }
+ cur_file = (struct filestatus*) iob->context;
+
+ /* Is there an opened file ? */
+ if( cur_file->fname[0] == 0 )
+ {
+#ifdef DEBUG
+ fprintf(stderr, "fsdos_read_block: File is not currently open!\n");
+#endif
+ errno = EBADF;
+ return -1;
+ }
+
+ amount_left_in_file = cur_file->file_length - block * 1024;
+
+ if (amount_left_in_file < 0)
+ {
+#ifdef DEBUG
+ fprintf(stderr, "EOF\n");
+#endif
+ return 0;
+ }
+
+ /* Are we before the EOF ? NB: FAT12 ONLY! */
+ if( cur_file->cur_cluster >= 0xFF0 || cur_file->cur_cluster < 2 )
+ {
+#ifdef DEBUG
+ fprintf(stderr, "Hit end of file; cluster 0x%03x\n",
+ cur_file->cur_cluster);
+#endif
+ return 0;
+ }
+
+ for(s=0; s<2; s++)
+ {
+ unsigned int sectno;
+
+ if (amount_left_in_file <= 0)
+ {
+#ifdef DEBUG
+ fprintf(stderr, "r2: Hit end of file\n");
+#endif
+ break;
+ }
+
+ sectno = dos_clust0
+ + cur_file->cur_cluster * dos_spc
+ + cur_file->sector_no % dos_spc;
+
+ if (rawio_read_sector(sectno, ptr) <= 0)
+ {
+#ifdef DEBUG
+ fprintf(stderr, "r2: rawio failed\n");
+#endif
+ return -1;
+ }
+
+ cur_file->sector_no++;
+ if( cur_file->sector_no % dos_spc == 0 )
+ {
+ int odd = (cur_file->cur_cluster&1);
+ unsigned int val, val2;
+
+ val = cur_file->cur_cluster + (cur_file->cur_cluster>>1);
+#ifdef BUFFER_FAT
+ val2 = get_uint(fat_buf, val);
+#else
+ if (rawio_read_sector(dos_fatpos+(val/512), sect) <= 0) return -1;
+ if( val%512 == 511 )
+ {
+ val2 = sect[511] & 0xFF;
+ if (rawio_read_sector(dos_fatpos+(val/512)+1, sect) <= 0) return -1;
+ val2 |= (sect[0]<<8);
+ }
+ else
+ val2 = get_uint(sect, (val%512));
+#endif
+
+ if( odd ) val2>>=4;
+
+ val2 &= 0xFFF;
+
+ cur_file->cur_cluster = val2;
+ }
+
+ amount_to_read = amount_left_in_file;
+ if (amount_to_read > 512) amount_to_read = 512;
+ ptr += amount_to_read;
+ amount_left_in_file -= amount_to_read;
+ }
+
+ return ptr - buffer;
+}
+
+static int read_bootblock()
+{
+ int rv, media_byte = 0;
+
+#ifdef DEBUG
+ printf("fs_dos:read_bootblock:\n");
+#endif
+ if (rawio_read_sector(1, sect) <= 0) return -1;
+ media_byte = *(unsigned char*)sect;
+
+ /* Valid media byte ? */
+ if( (media_byte & 0xF0) != 0xF0 ) return -1;
+ if (rawio_read_sector(0, sect) <= 0) return -1;
+
+ if( DOS_MEDIA(sect) != media_byte ) return -1;
+ if( DOS_SPT(sect) > 63 ) return -1;
+ if( DOS_SECT(sect) != 512 ) return -1;
+
+ if( last_serial != DOS4_SERIAL(sect) ) fsdos_close_file();
+ last_serial = DOS4_SERIAL(sect);
+
+ /* Collect important data */
+ dir_sect = DOS_RESV(sect) + DOS_NFAT(sect)*DOS_FATLEN(sect);
+ dir_nentry = DOS_NROOT(sect);
+
+ dos_fatpos = DOS_RESV(sect);
+ dos_spc = DOS_CLUST(sect);
+ if( dos_spc < 1 ) dos_spc = 1;
+ dos_clust0 = dir_sect + (dir_nentry+15)/16 - 2*dos_spc;
+
+ if( rawio_disk_cyls == 0 )
+ {
+ rawio_disk_spt = DOS_SPT(sect);
+ rawio_disk_heads = DOS_HEADS(sect);
+ }
+
+#ifdef DEBUG
+ printf("read_bootblock: heads(%d), spt(%d), dir_sect(%d)\n",
+ rawio_disk_heads,
+ rawio_disk_spt,
+ dir_sect);
+#endif
+ return 0;
+}
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