1 files changed, 104 insertions, 0 deletions
diff --git a/kernel/features/proc.c b/kernel/features/proc.c
new file mode 100644
index 0000000..a14aaea
--- /dev/null
+++ b/kernel/features/proc.c
@@ -0,0 +1,104 @@
+// MIT License, Copyright (c) 2020 Marvin Borner
+
+#include <cpu.h>
+#include <interrupts.h>
+#include <load.h>
+#include <mem.h>
+#include <print.h>
+#include <proc.h>
+#include <str.h>
+#include <timer.h>
+
+u32 pid = 0;
+struct proc *root;
+struct proc *current;
+struct proc *last;
+
+void scheduler(struct regs *regs)
+{
+	if (current)
+		memcpy(&current->regs, regs, sizeof(struct regs));
+
+	timer_handler();
+
+	if (current && current->next)
+		current = current->next;
+	else
+		current = root;
+
+	while (current->state == PROC_ASLEEP)
+		if (!current->next)
+			current = root;
+		else
+			current = current->next;
+
+	/* proc_print(); */
+	memcpy(regs, &current->regs, sizeof(struct regs));
+
+	if (regs->cs != GDT_USER_CODE_OFFSET) {
+		regs->gs = GDT_USER_DATA_OFFSET;
+		regs->fs = GDT_USER_DATA_OFFSET;
+		regs->es = GDT_USER_DATA_OFFSET;
+		regs->ds = GDT_USER_DATA_OFFSET;
+		regs->ss = GDT_USER_DATA_OFFSET;
+		regs->cs = GDT_USER_CODE_OFFSET;
+		regs->eflags = EFLAGS_ALWAYS | EFLAGS_INTERRUPTS;
+	}
+	printf("%d", current->pid);
+}
+
+void proc_print()
+{
+	struct proc *proc = root;
+
+	printf("\n");
+	while (proc) {
+		printf("Process %d [%s]: %s\n", proc->pid,
+		       proc->state == PROC_RUNNING ? "running" : "sleeping", proc->name);
+		proc = proc->next;
+	}
+	printf("\n");
+}
+
+void proc_attach(struct proc *proc)
+{
+	if (!last->next) {
+		last->next = proc;
+	} else {
+		struct proc *save = last;
+		while (save->next)
+			save = save->next;
+		save->next = proc;
+	}
+}
+
+struct proc *proc_make()
+{
+	struct proc *proc = malloc(sizeof(*proc));
+	proc->pid = pid++;
+	proc->state = PROC_RUNNING;
+	proc->next = NULL;
+
+	if (current)
+		proc_attach(proc);
+	last = proc;
+	return proc;
+}
+
+extern void proc_jump_userspace();
+
+u32 _esp, _eip;
+void proc_init()
+{
+	cli();
+	irq_install_handler(0, scheduler);
+
+	root = proc_make();
+	bin_load("/init", root);
+	strcpy(root->name, "root");
+	proc_print();
+
+	_eip = root->regs.eip;
+	_esp = root->regs.esp;
+	proc_jump_userspace();
+}