From b5289fd749bc4d2637610d712f8fe650f214f1d5 Mon Sep 17 00:00:00 2001
From: Rich Felker <dalias@aerifal.cx>
Date: Sat, 25 Aug 2012 22:49:47 -0400
Subject: [PATCH] add c11 quick_exit and at_quick_exit functions

---
 include/stdlib.h         |  2 ++
 src/exit/at_quick_exit.c | 29 +++++++++++++++++++++++++++++
 src/exit/quick_exit.c    | 15 +++++++++++++++
 3 files changed, 46 insertions(+)
 create mode 100644 src/exit/at_quick_exit.c
 create mode 100644 src/exit/quick_exit.c

diff --git a/include/stdlib.h b/include/stdlib.h
index 0a8de866..c1d93e71 100644
--- a/include/stdlib.h
+++ b/include/stdlib.h
@@ -43,6 +43,8 @@ void abort (void);
 int atexit (void (*) (void));
 void exit (int);
 void _Exit (int);
+int at_quick_exit (void (*) (void));
+void quick_exit (int);
 
 char *getenv (const char *);
 
diff --git a/src/exit/at_quick_exit.c b/src/exit/at_quick_exit.c
new file mode 100644
index 00000000..85c3d26e
--- /dev/null
+++ b/src/exit/at_quick_exit.c
@@ -0,0 +1,29 @@
+#include <stdlib.h>
+#include "libc.h"
+
+#define COUNT 32
+
+static void (*funcs[COUNT])(void);
+static int count;
+static int lock[2];
+
+void __funcs_on_quick_exit()
+{
+	void (*func)(void);
+	LOCK(lock);
+	while (count > 0) {
+		func = funcs[--count];
+		UNLOCK(lock);
+		func();
+		LOCK(lock);
+	}
+}
+
+int at_quick_exit(void (*func)(void))
+{
+	if (count == 32) return -1;
+	LOCK(lock);
+	funcs[count++] = func;
+	UNLOCK(lock);
+	return 0;
+}
diff --git a/src/exit/quick_exit.c b/src/exit/quick_exit.c
new file mode 100644
index 00000000..18d5288a
--- /dev/null
+++ b/src/exit/quick_exit.c
@@ -0,0 +1,15 @@
+#include <stdlib.h>
+#include "syscall.h"
+#include "atomic.h"
+#include "libc.h"
+
+static void dummy() { }
+weak_alias(dummy, __funcs_on_quick_exit);
+
+void quick_exit(int code)
+{
+	static int lock;
+	while (a_swap(&lock, 1)) __syscall(SYS_pause);
+	__funcs_on_quick_exit();
+	_Exit(code);
+}
-- 
2.20.1