feat: add boot counting

.gitignore

@@ -5,6 +5,7 @@
 bootloader_emu
 busybox
 busybox.tar.bz2
+counted_disk
 demo_uki.img
 demo.img
 dependencies.make

Makefile

@@ -1,7 +1,7 @@
 MAKEFLAGS += --no-builtin-rules
 .SILENT:
 UNIT_TESTS := loader fat32 io_buf
-.PHONY: all clean distclean test unit_tests qemu_test uki_test kexec_test emu_test $(UNIT_TESTS:%=run_test_%)
+.PHONY: all clean distclean test unit_tests qemu_test uki_test kexec_test boot_count_test emu_test $(UNIT_TESTS:%=run_test_%)
 
 CC := gcc
 CC_X86 := x86_64-linux-gnu-gcc
@@ -24,7 +24,7 @@ OBJDUMP_FLAGS_M16 := -m i8086 -M intel
 
 all: disk uki.efi kexec.cpio bootloader_emu kernel
 
-test: unit_tests emu_test qemu_test uki_test kexec_test
+test: unit_tests emu_test qemu_test uki_test kexec_test boot_count_test
 
 unit_tests: $(UNIT_TESTS:%=run_test_%)
 
@@ -63,6 +63,12 @@ kexec_test: kernel kexec.cpio
 	grep -F 'kexec_core: Starting new kernel' < serial.log > /dev/null
 	grep -F 'hello from the initrd' < serial.log > /dev/null
 
+boot_count_test: counted_disk
+	echo 'running $< in qemu'
+	./run_vm.sh -n '$<' | tee serial.log
+	grep -F 'Failed to load kernel' < serial.log > /dev/null
+	grep -F 'hello from the initrd' < serial.log > /dev/null
+
 debug: disk bootloader.elf
 	echo 'running $< in qemu in debug mode'
 	./debug.sh $^
@@ -114,6 +120,10 @@ disk: make_disk.sh mbr.bin bootloader.bin kernel initrd.cpio
 	echo 'creating $@'
 	./$^ $@
 
+counted_disk: make_counted_disk.sh mbr.bin bootloader.bin kernel initrd.cpio
+	echo 'creating $@'
+	./$^ $@
+
 demo: demo.img demo_uki.img
 
 demo.img: make_demo.sh mbr.bin bootloader.bin kernel busybox

fat32.c

@@ -311,9 +311,10 @@ static struct fat32_dir_entry * next_entry(struct fat32_dir_entry **entries, uin
 	return (void *) 0;
 }
 
-int16 for_each_dir_entry(void (*callback)(const char *entry_name, uint32 entry_cluster, uint32 entry_size))
+int16 for_each_dir_entry(void (*callback)(const char *entry_name, int32 entry_index, uint32 entry_cluster, uint32 entry_size))
 {
 	int16 error;
+	struct fat32_dir_entry *entries_start;
 	struct fat32_dir_entry *entries;
 	uint32 entries_len;
 	struct fat32_dir_entry *entry;
@@ -323,17 +324,83 @@ int16 for_each_dir_entry(void (*callback)(const char *entry_name, uint32 entry_c
 	error = load_dir();
 	if (error != 0) return error;
 
-	entries     = dir_cache.buf;
-	entries_len = dir_cache.num_entries;
+	entries_start = dir_cache.buf;
+	entries       = entries_start;
+	entries_len   = dir_cache.num_entries;
 
 	while ((entry = next_entry(&entries, &entries_len, &entry_name)) != (void *) 0) {
 		entry_cluster = (((uint32) entry->cluster_high) << 0x10) + entry->cluster_low;
-		callback(entry_name, entry_cluster, entry->size);
+		callback(entry_name, (int32)(entry - entries_start), entry_cluster, entry->size);
+	}
+
+	return 0;
+}
+
+struct dir_entry_handle make_handle(int32 entry_index)
+{
+	struct dir_entry_handle h;
+	h.dir_cluster = fs.current_dir;
+	h.entry_index = entry_index;
+	return h;
+}
+
+int16 open_handle(struct dir_entry_handle h)
+{
+	int16 error;
+	struct fat32_dir_entry *entry;
+
+	fs.current_dir = h.dir_cluster;
+
+	error = load_dir();
+	if (error != 0) return error;
+
+	if (h.entry_index < 0 || (uint32) h.entry_index >= dir_cache.num_entries) {
+		print_str("Handle entry_index out of range\r\n");
+		return -1;
 	}
 
+	entry = &dir_cache.buf[h.entry_index];
+
+	open_cluster((((uint32) entry->cluster_high) << 0x10) + entry->cluster_low, entry->size);
+	file.entry_index = h.entry_index;
+
 	return 0;
 }
 
+int16 get_file_name(char *name_out, uint16 name_out_len)
+{
+	int16 error;
+	struct fat32_dir_entry *entries_start;
+	struct fat32_dir_entry *entries;
+	uint32 entries_len;
+	struct fat32_dir_entry *entry;
+	char *entry_name;
+	uint16 i;
+
+	if (file.entry_index < 0) {
+		print_str("No file opened\r\n");
+		return -1;
+	}
+
+	error = load_dir();
+	if (error != 0) return error;
+
+	entries_start = dir_cache.buf;
+	entries       = entries_start;
+	entries_len   = dir_cache.num_entries;
+
+	while ((entry = next_entry(&entries, &entries_len, &entry_name)) != (void *) 0) {
+		if ((int32)(entry - entries_start) == file.entry_index) {
+			for (i = 0; i + 1 < name_out_len && entry_name[i] != 0x00; ++i) name_out[i] = entry_name[i];
+			name_out[i] = 0x00;
+			return 0;
+		}
+	}
+
+	print_str("Entry index not found in directory\r\n");
+	return -1;
+}
+
 void open_cluster(uint32 cluster, uint32 size)
 {
 	file.size = size;

fat32.h

@@ -2,6 +2,11 @@
 
 #include "prefix.h"
 
+struct dir_entry_handle {
+	uint32 dir_cluster;
+	int32  entry_index;
+};
+
 int16 PREFIX(load_fat32)(void);
 int16 PREFIX(open)(const char *file);
 void PREFIX(open_cluster)(uint32 cluster, uint32 size);
@@ -10,7 +15,10 @@ int16 PREFIX(chdir)(const char *dir);
 int16 PREFIX(unlink)(void);
 int16 PREFIX(link)(const char *name);
 int16 PREFIX(rename)(const char *name);
-int16 PREFIX(for_each_dir_entry)(void (*callback)(const char *entry_name, uint32 entry_cluster, uint32 entry_size));
+int16 PREFIX(for_each_dir_entry)(void (*callback)(const char *entry_name, int32 entry_index, uint32 entry_cluster, uint32 entry_size));
+struct dir_entry_handle PREFIX(make_handle)(int32 entry_index);
+int16 PREFIX(open_handle)(struct dir_entry_handle h);
+int16 PREFIX(get_file_name)(char *name_out, uint16 name_out_len);
 void PREFIX(reset_seek)(void);
 int16 PREFIX(seek)(uint32 sectors);
 uint32 PREFIX(read)(uint8 *buf, uint32 sectors);

hello.c

@@ -1,7 +1,9 @@
 #include <stdio.h>
+#include <sys/reboot.h>
 
 int main()
 {
 	puts("hello from the initrd");
+	reboot(RB_POWER_OFF);
 	return 0;
 }