Filesystem part 1: FAT32 image bootstrapping

.gitignore

@@ -1,8 +1,6 @@
 *.o
-bochslog.txt
 build/
 kernel.elf
-os.iso
-blankos.iso
-real/
+blankos-fat.img
 i386-elf-7.5.0-Linux-x86_64/
+i386-elf-7.5.0-Linux-x86_64.tar.xz

bochsrc.txt

@@ -1,10 +0,0 @@
-megs:            32
-display_library: x 
-romimage:        file=/usr/share/bochs/BIOS-bochs-legacy
-vgaromimage:     file=/usr/share/bochs/VGABIOS-lgpl-latest
-ata0-master:     type=cdrom, path=os.iso, status=inserted
-boot:            cdrom
-log:             bochslog.txt
-clock:           sync=realtime, time0=local
-cpu:             count=1, ips=1000000
-com1:            enabled=1, mode=file, dev=com1.out

iso/boot/grub/menu.lst

@@ -1,5 +0,0 @@
-default=0
-timeout=0
-
-title os
-kernel /boot/kernel.elf

makefile

@@ -1,5 +1,5 @@
 CC = i386-elf-7.5.0-Linux-x86_64/bin/i386-elf-gcc
-CFLAGS = -Wall -Wextra -Wno-builtin-declaration-mismatch -c -I src/
+CFLAGS = -g -Wall -Wextra -Wno-builtin-declaration-mismatch -c -I src/
 LDFLAGS = -T link.ld -melf_i386
 AS = nasm
 ASFLAGS = -f elf
@@ -16,6 +16,9 @@ ASM_SOURCES = $(wildcard $(KERNEL_DIR)/*.s) $(wildcard $(LIBC_DIR)/*.s) $(wildca
 
 OBJECTS = $(patsubst $(SRC_DIR)/%, $(OBJ_DIR)/%, $(C_SOURCES:.c=.o) $(ASM_SOURCES:.s=.o))
 
+TOOLCHAIN_SRC = https://newos.org/toolchains/i386-elf-7.5.0-Linux-x86_64.tar.xz
+TOOLCHAIN_FILE = i386-elf-7.5.0-Linux-x86_64.tar.xz
+
 all: $(OBJ_DIR) kernel.elf
 
 $(OBJ_DIR):
@@ -32,31 +35,17 @@ $(OBJ_DIR)/%.o: $(SRC_DIR)/%.s
 	$(AS) $(ASFLAGS) $< -o $@
 
 toolchain:
-	wget https://newos.org/toolchains/i386-elf-7.5.0-Linux-x86_64.tar.xz
-	tar xf i386-elf-7.5.0-Linux-x86_64.tar.xz
+	wget $(TOOLCHAIN_SRC)
+	tar xf $(TOOLCHAIN_FILE)
 
-os.iso: kernel.elf
-	cp kernel.elf iso/boot/kernel.elf
-	genisoimage -R                              \
-							-b boot/grub/stage2_eltorito    \
-							-no-emul-boot                   \
-							-boot-load-size 4               \
-							-A os                           \
-							-input-charset utf8             \
-							-quiet                          \
-							-boot-info-table                \
-							-o os.iso                       \
-							iso
+blankos-fat.img:
+	sudo ./setup.sh
 
-real: kernel.elf
-	mkdir -p real/boot/grub
-	cp kernel.elf real/boot/kernel.elf
-	cp grub.cfg real/boot/grub/grub.cfg
-	grub-mkrescue real -o blankos.iso
+run: blankos-fat.img
+	qemu-system-i386 -drive file=blankos-fat.img,format=raw
 
-run: os.iso
-	bochs -f bochsrc.txt -q 
+debug:
+	qemu-system-i386 -s -S -drive file=blankos-fat.img,format=raw
 
 clean:
-	rm -rf $(OBJ_DIR) kernel.elf os.iso blankos.iso real
-
+	rm -rf $(OBJ_DIR) kernel.elf blankos-fat.img $(TOOLCHAIN_FILE)

setup.sh

@@ -0,0 +1,75 @@
+#!/bin/bash
+
+# A script to create a FAT32 loopback device, place a kernel onto it, and install GRUB.
+# Inspired by JakeSteinburger's SpecOS setup script!
+
+if [ "$EUID" -ne 0 ]; then
+    echo "Please execute this script with root privileges."
+    exit
+fi
+
+if [ -f "blankos-fat.img" ]; then
+    echo "Deleting previous disk image..."
+    rm blankos-fat.img
+fi
+
+if [ -d "/mnt/blankos" ]; then
+    echo "Deleting previous mountpoint..."
+    rm -rf /mnt/blankos
+fi
+
+echo "Creating new mountpoint..."
+mkdir /mnt/blankos
+
+echo "Creating an empty disk image..."
+dd if=/dev/zero of=blankos-fat.img bs=512 count=131072
+
+echo "Appending a parition to disk image..."
+fdisk blankos-fat.img << EOF
+n
+p
+1
+
+
+a
+w
+EOF
+
+echo "Creating loopback devices..."
+losetup -fP blankos-fat.img
+
+# Get first partition loopback
+LOOP_DEVICE=$(losetup -l | grep blankos-fat.img | awk '{print $1}')
+PARTITION="${LOOP_DEVICE}p1"
+
+echo "Creating FAT32 partition..."
+mkfs.vfat -F 32 $PARTITION
+
+echo "Mounting partition..."
+mount $PARTITION /mnt/blankos
+
+echo "Installing GRUB on $LOOP_DEVICE"
+grub-install --root-directory=/mnt/blankos --target=i386-pc --no-floppy --modules="normal part_msdos fat multiboot" $LOOP_DEVICE
+
+echo "Copying kernel file and GRUB configuration file..."
+
+cp kernel.elf /mnt/blankos/boot/
+cp grub.cfg /mnt/blankos/boot/grub/
+
+echo "Appending test files..."
+mkdir /mnt/blankos/hello
+echo "Hello, world from FAT32 text file." > /mnt/blankos/hello/testfile.txt
+
+# cp program.elf /mnt/blankos/programs/
+# In the future, when the OS can load programs and parse ELF
+
+echo "Unmounting partition..."
+umount /mnt/blankos
+
+echo "Freeing loopback devices..."
+losetup -d $LOOP_DEVICE
+
+echo "Fixing disk image permissions..."
+sudo chmod 666 blankos-fat.img
+
+echo "The blankos-fat.img disk image is ready for use with QEMU or real hardware."