sched: free up thread and process memory after waitpid()

Author: jewelcodes

src/sched/cleanup.c

@@ -0,0 +1,79 @@
+/*
+ * lux - a lightweight unix-like operating system
+ * Omar Elghoul, 2024
+ * 
+ * Core Microkernel
+ */
+
+#include <string.h>
+#include <stdlib.h>
+#include <kernel/sched.h>
+#include <platform/platform.h>
+
+/* threadCleanup(): frees all memory associated with a thread and removes it
+ * from the run queues
+ * params: t - thread structure
+ * returns: nothing
+ */
+
+void threadCleanup(Thread *t) {
+    platformCleanThread(t->context, t->highest);
+
+    Process *pc = getProcess(t->pid);
+    Process *pq = getProcessQueue();
+    Thread *tq;
+
+    while(pq) {
+        if(!pq->threadCount || !pq->threads) {
+            pq = pq->next;
+            continue;
+        }
+
+        for(int i = 0; i < pq->threadCount; i++) {
+            if(pq->threads[i] == t) {
+                if(i != pq->threadCount-1)
+                    memmove(&pq->threads[i], &pq->threads[i+1], (pq->threadCount-i) * sizeof(Thread *));
+                else
+                    pq->threads[i] = NULL;
+
+                pq->threadCount--;
+                break;
+            } else {
+                // remove from the next queues as well
+                tq = pq->threads[i];
+                if(tq->next == t) tq->next = t->next;
+            }
+        }
+
+        pq = pq->next;
+    }
+
+    // now remove the process that contains this thread if necessary
+    if(!pc->threadCount) {
+        pq = getProcessQueue();
+
+        while(pq) {
+            if(pq->next == pc) pq->next = pc->next;
+            pq = pq->next;
+        }
+
+        pq = getProcess(pc->parent);
+        for(int i = 0; i < pq->childrenCount; i++) {
+            if(pq->children[i] == pc) {
+                if(i != pq->childrenCount-1)
+                    memmove(&pq->children[i], &pq->children[i+1], (pq->childrenCount-i) * sizeof(Process *));
+                else
+                    pq->children[i] = NULL;
+                
+                pq->childrenCount--;
+                break;
+            }
+        }
+
+        free(pc->children);
+        free(pc->threads);
+        free(pc);
+    }
+
+    free(t);
+}

src/sched/waitpid.c

@@ -31,7 +31,6 @@ static pid_t processStatus(Process *p, int *status) {
 
             // free the thread structure
             threadCleanup(t);
-
             return pid;
         }
     }