From 4abab5ad6c8465a7528ccdd5f49367da05f78bbd Mon Sep 17 00:00:00 2001
From: Vladimir Azarov <avm@intermediate-node.net>
Date: Tue, 1 Oct 2024 15:47:05 +0200
Subject: Initial version

---
 src/thread/pthread_atfork.c | 55 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)
 create mode 100644 src/thread/pthread_atfork.c

(limited to 'src/thread/pthread_atfork.c')

diff --git a/src/thread/pthread_atfork.c b/src/thread/pthread_atfork.c
new file mode 100644
index 0000000..26d3254
--- /dev/null
+++ b/src/thread/pthread_atfork.c
@@ -0,0 +1,55 @@
+#include <pthread.h>
+#include <errno.h>
+#include "libc.h"
+#include "lock.h"
+
+#define malloc __libc_malloc
+#define calloc undef
+#define realloc undef
+#define free undef
+
+static struct atfork_funcs {
+	void (*prepare)(void);
+	void (*parent)(void);
+	void (*child)(void);
+	struct atfork_funcs *prev, *next;
+} *funcs;
+
+static volatile int lock[1];
+
+void __fork_handler(int who)
+{
+	struct atfork_funcs *p;
+	if (!funcs) return;
+	if (who < 0) {
+		LOCK(lock);
+		for (p=funcs; p; p = p->next) {
+			if (p->prepare) p->prepare();
+			funcs = p;
+		}
+	} else {
+		for (p=funcs; p; p = p->prev) {
+			if (!who && p->parent) p->parent();
+			else if (who && p->child) p->child();
+			funcs = p;
+		}
+		UNLOCK(lock);
+	}
+}
+
+int pthread_atfork(void (*prepare)(void), void (*parent)(void), void (*child)(void))
+{
+	struct atfork_funcs *new = malloc(sizeof *new);
+	if (!new) return ENOMEM;
+
+	LOCK(lock);
+	new->next = funcs;
+	new->prev = 0;
+	new->prepare = prepare;
+	new->parent = parent;
+	new->child = child;
+	if (funcs) funcs->prev = new;
+	funcs = new;
+	UNLOCK(lock);
+	return 0;
+}
-- 
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