1 files changed, 49 insertions, 0 deletions
diff --git a/sys/rt/atexit.c b/sys/rt/atexit.c
new file mode 100644
index 0000000..208cc6e
--- /dev/null
+++ b/sys/rt/atexit.c
@@ -0,0 +1,49 @@
+#include <u.h>
+#include <rt.h>
+
+#define COUNT 32
+
+static struct cleaner
+{
+    struct cleaner *next;
+    void (*clean[COUNT])(void *);
+    void *arg[COUNT];
+} arena, *head;
+static int slot;
+
+void weaklink exit(int code){};
+
+void
+rt·clean(void)
+{
+    void (*clean)(void *), *arg;
+    /*LOCK*/
+    for(; head; head=head->next, slot=COUNT) {
+        while(slot-- > 0){
+            arg   = head->arg[slot];
+            clean = head->clean[slot];
+            /* UNLOCK */
+            clean(arg);
+            /* LOCK */
+        }
+    }
+}
+
+int
+rt·atexit(void (*clean)(void *), void *arg)
+{
+    /* LOCK */
+    if(!head)
+        head = &arena;
+
+    /* we need malloc... */
+    if(slot==COUNT)
+        return -1;
+
+    head->arg[slot]   = arg;
+    head->clean[slot] = clean;
+    slot++;
+
+    /* UNLOCK */
+    return 0;
+}