doing iso9660 before gpt, making partition detection expandable

makefile

@@ -11,19 +11,20 @@ files: out
 	cp -r src/skel/* out/fs/
 
 kernel: obj out
-	nasm src/kernel/keyb.asm   -o obj/kkeyba.o  -f elf32
+	nasm src/kernel/keyb.asm     -o obj/kkeyba.o   -f elf32
-	nasm src/kernel/serial.asm -o obj/kserial.o -f elf32
+	nasm src/kernel/serial.asm   -o obj/kserial.o  -f elf32
-	nasm src/kernel/stub.asm   -o obj/kstub.o   -f elf32
+	nasm src/kernel/stub.asm     -o obj/kstub.o    -f elf32
-	gcc -c src/kernel/diskio.c -o obj/kdiskio.o -ffreestanding -nostdlib -m32
+	gcc  -c src/kernel/diskio.c  -o obj/kdiskio.o  -ffreestanding -nostdlib -m32
-	gcc -c src/kernel/files.c  -o obj/kfiles.o  -ffreestanding -nostdlib -m32
+	gcc  -c src/kernel/files.c   -o obj/kfiles.o   -ffreestanding -nostdlib -m32
-	gcc -c src/kernel/gpt.c    -o obj/kgpt.o    -ffreestanding -nostdlib -m32
+	#gcc -c src/kernel/gpt.c     -o obj/kgpt.o     -ffreestanding -nostdlib -m32
-	gcc -c src/kernel/keyb.c   -o obj/kkeybc.o  -ffreestanding -nostdlib -m32
+	gcc  -c src/kernel/iso9660.c -o obj/kiso9660.o -ffreestanding -nostdlib -m32
-	gcc -c src/kernel/main.c   -o obj/kmain.o   -ffreestanding -nostdlib -m32
+	gcc  -c src/kernel/keyb.c    -o obj/kkeybc.o   -ffreestanding -nostdlib -m32
-	gcc -c src/kernel/mem.c    -o obj/kmem.o    -ffreestanding -nostdlib -m32
+	gcc  -c src/kernel/main.c    -o obj/kmain.o    -ffreestanding -nostdlib -m32
-	gcc -c src/kernel/proc.c   -o obj/kproc.o   -ffreestanding -nostdlib -m32
+	gcc  -c src/kernel/mem.c     -o obj/kmem.o     -ffreestanding -nostdlib -m32
-	gcc -c src/kernel/vga.c    -o obj/kvga.o    -ffreestanding -nostdlib -m32
+	gcc  -c src/kernel/proc.c    -o obj/kproc.o    -ffreestanding -nostdlib -m32
+	gcc  -c src/kernel/vga.c     -o obj/kvga.o     -ffreestanding -nostdlib -m32
 	ld obj/kkeyba.o obj/kserial.o obj/kstub.o obj/kdiskio.o obj/kfiles.o \
-		obj/kgpt.o obj/kkeybc.o obj/kmain.o obj/kmem.o obj/kproc.o obj/kvga.o \
+		obj/kiso9660.o obj/kkeybc.o obj/kmain.o obj/kmem.o obj/kproc.o obj/kvga.o \
 		-o out/kernel.elf -T src/kernel/link.ld -s --orphan-handling=discard -melf_i386
 
 clean:

src/kernel/files.c

@@ -19,11 +19,21 @@ OF THIS SOFTWARE.
 
 #include "files.h"
 #include "diskio.h"
-#include "gpt.h"
+#include "iso9660.h"
+#include "mem.h"
+
+bool (*const parse_pts[N_PT_FORMATS])(uint8_t dn, uint8_t *buffer) = {
+  //&gpt_parse_pt,
+  //&mbr_parse_pt
+};
+
+bool (*const parse_phs[N_FS_FORMATS])(uint8_t dn, uint32_t sector, uint8_t *buffer) = {
+  &iso_9660_parse_ph
+};
 
 uint8_t working_drive;
 uint8_t working_part;
-uint8_t buffer[1024];
+uint8_t buffer[2048];
 
 void set_working_drive(uint8_t name, uint8_t part) {
   if ((name >= (uint8_t)'a') && (name <= (uint8_t)'z') &&
@@ -74,13 +84,28 @@ uint32_t read_line_file(uint16_t handle, uint32_t max, void *buffer) {
 void detect_disk_parts(uint8_t drive) {
   if ((drive >= (uint8_t)'a') && (drive <= (uint8_t)'z')) {
     uint8_t dn = (drive & 0x1f) - 1;
+    for (uint8_t i = 0; i < part_info[dn].n_partitions; ++i)
+      if (part_info[dn].partition_cache[i])
+        deallocate_block(part_info[dn].partition_cache[i]);
     update_status(dn);
     if (drives[dn].flags & (PRESENT | DISK_IN)) {
-      read_sectors(dn, 0, 2, buffer);
+      /*ISO 9660 often comes with a dummy MBR*/
-      if ((*(uint32_t *)&buffer[0x200] == 0x20494645) &&//EFI
+      if (iso_9660_parse_ph(dn, 0, buffer)) {
-          (*(uint32_t *)&buffer[0x204] == 0x54524150))  //PART
+        part_info[dn].format = DIRECT;
-        part_info[dn].format = gpt_parse_pt(dn, buffer) ? GPT : UNKNOWN;
+        part_info[dn].n_partitions = 1;
-      ;
+        return;
+      }
+      for (uint8_t ptt = 0; ptt < N_PT_FORMATS; ++ptt)
+        if (parse_pts[ptt](dn, buffer))
+          return;
+      for (uint8_t fst = 0; fst < N_FS_FORMATS; ++fst)
+        if (parse_phs[fst](dn, 0, buffer)) {
+          part_info[dn].format = DIRECT;
+          part_info[dn].n_partitions = 1;
+          return;
+        }
+      part_info[dn].format = UNKNOWN;
+      part_info[dn].n_partitions = 0;
     }
     else {
       part_info[dn].format = NOT_PRESENT;

src/kernel/files.h

@@ -30,17 +30,22 @@ struct file_info {
 };
 
 enum fs_format {
-  ISO9660
+  ISO_9660 = 0
 };
 
+#define N_FS_FORMATS 1
+
 enum pt_format {
   NOT_PRESENT = 0,
   UNKNOWN = 1,
   DIRECT = 2,
-  MBR = 3,
+
-  GPT = 4
+  //GPT = 3,
+  //MBR = 4,
 };
 
+#define N_PT_FORMATS 0
+
 struct drive_parts {
   uint8_t format;
   uint8_t n_partitions;

src/kernel/gpt.c

@@ -29,10 +29,10 @@ bool gpt_parse_pt(uint8_t dn, uint8_t *buffer) {
   uint32_t part_entry_size = head->part_size;
   struct gpt_entry *as_entries = (struct gpt_entry *)buffer;
   for (uint8_t i = 0; i < pi->n_partitions; ++i) {
-    if (!(i % 8))
+    if (!(i % 16))
-      read_sectors(dn, 2 + i / 4, 2, buffer);
+      read_sectors(dn, 2 + i / 4, 4, buffer);
-    pi->partition_sizes[i] = ((as_entries[i % 8].last_sector + 1) >> 1) - (pi->partition_offsets[i] = ((as_entries[i % 8].sector) >> 1));
+    pi->partition_sizes[i] = ((as_entries[i % 16].last_sector + 1) >> 1) - (pi->partition_offsets[i] = ((as_entries[i % 16].sector) >> 1));
-    switch (as_entries[i % 8].id.le) {
+    switch (as_entries[i % 16].id.le) {
     //TODO
     }
   }

src/kernel/iso9660.c

@@ -0,0 +1,24 @@
+/*
+Copyright 2019 Benji Dial
+
+Permission to use, copy, modify, and/or distribute this
+software for any purpose with or without fee is hereby
+granted, provided that the above copyright notice and this
+permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS
+ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO
+EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
+RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
+ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
+OF THIS SOFTWARE.
+*/
+
+#include "iso9660.h"
+
+bool iso_9660_parse_ph(uint8_t dn, uint32_t sector, uint8_t *buffer) {
+  //TODO
+}

src/kernel/iso9660.h

@@ -0,0 +1,34 @@
+/*
+Copyright 2019 Benji Dial
+
+Permission to use, copy, modify, and/or distribute this
+software for any purpose with or without fee is hereby
+granted, provided that the above copyright notice and this
+permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS
+ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO
+EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
+RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
+ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
+OF THIS SOFTWARE.
+*/
+
+#include <stdint.h>
+#include <stdbool.h>
+
+#ifndef ISO9660_H
+#define ISO9660_H
+
+struct iso_9660_volume_descriptor_start {
+  uint8_t type;
+  uint8_t id[5];
+  uint8_t version;
+} __attribute__ ((__packed__));
+
+bool iso_9660_parse_ph(uint8_t dn, uint32_t sector, uint8_t *buffer);
+
+#endif