[MULTITASKING] Processes

kernel/proc/process.c

@@ -0,0 +1,91 @@
+#include <process.h>
+#include <thread.h>
+#include <debug.h>
+#include <scheduler.h>
+
+uint64_t pid = 1;
+process_t *init_proc = 0;
+
+process_t *process_spawn(process_t *parent)
+{
+  process_t *proc = kcalloc(1, sizeof(process_t));
+  proc->pid = pid++;
+  proc->parent =  parent;
+  proc->P4 = vmm_new_P4();
+  proc->state = PROC_STATE_READY;
+
+  LIST_INIT(proc, children);
+  LIST_INIT(proc, siblings);
+  LIST_INIT(proc, threads);
+
+  if(parent)
+  {
+    LIST_APPEND(parent->children, proc, siblings);
+  }
+
+  if(proc->pid == 1)
+    init_proc = proc;
+
+  return proc;
+}
+
+void process_attach(process_t *proc, thread_t *th)
+{
+  LIST_APPEND(proc->threads, th, process_threads);
+  th->process = proc;
+}
+
+void switch_process(process_t *proc)
+{
+  process_t *old = get_current_process();
+  if(old)
+  {
+    if(old == proc)
+      return;
+    if(old->state == PROC_STATE_RUNNING)
+      old->state = PROC_STATE_READY;
+  }
+  set_current_process(proc);
+
+  if(proc)
+  {
+    proc->state = PROC_STATE_RUNNING;
+    vmm_set_P4(proc->P4);
+  }
+  else
+  {
+    vmm_set_P4(0);
+  }
+}
+
+void process_exit(process_t *proc, uint64_t status)
+{
+  proc->status = status;
+  LIST_FOREACH(proc->children, process_t, c, siblings)
+  {
+    // Make init process adopt orphaned children
+    LIST_REMOVE(proc->children, c, siblings);
+    c->parent = init_proc;
+    LIST_APPEND(init_proc->children, c, siblings);
+  }
+  proc->state = PROC_STATE_ZOMBIE;
+}
+
+void process_free(process_t *proc)
+{
+  if(proc->state != PROC_STATE_ZOMBIE)
+  {
+    debug_error("Trying to free an unfinished process!\n");
+    for(;;);
+  }
+  LIST_FOREACH(proc->threads, thread_t, th, process_threads)
+  {
+    while(th->state == THREAD_STATE_RUNNING || th->state == THREAD_STATE_READY) schedule();
+    free_thread(th);
+  }
+  LIST_REMOVE(proc->parent->children, proc, siblings);
+  // Free page directory
+  vmm_free_P4(proc->P4);
+  // Free process structure
+  kfree(proc);
+}