4 files changed, 22 insertions, 0 deletions

diff --git a/libexec/rtld-elf/Symbol.map b/libexec/rtld-elf/Symbol.map
index 325362c8ad6e..20f8d60f3611 100644
--- a/libexec/rtld-elf/Symbol.map
+++ b/libexec/rtld-elf/Symbol.map
@@ -21,4 +21,6 @@ FBSDprivate_1.0 {
     _rtld_thread_init;
     _rtld_allocate_tls;
     _rtld_free_tls;
+    _rtld_atfork_pre;
+    _rtld_atfork_post;
 };
diff --git a/libexec/rtld-elf/rtld.c b/libexec/rtld-elf/rtld.c
index 144ea6c76c63..f67093ab0099 100644
--- a/libexec/rtld-elf/rtld.c
+++ b/libexec/rtld-elf/rtld.c
@@ -206,6 +206,8 @@ static func_ptr_type exports[] = {
     (func_ptr_type) &_rtld_allocate_tls,
     (func_ptr_type) &_rtld_free_tls,
     (func_ptr_type) &dl_iterate_phdr,
+    (func_ptr_type) &_rtld_atfork_pre,
+    (func_ptr_type) &_rtld_atfork_post,
     NULL
 };
 
diff --git a/libexec/rtld-elf/rtld_lock.c b/libexec/rtld-elf/rtld_lock.c
index 5bb891a2ae82..bf4caf71176b 100644
--- a/libexec/rtld-elf/rtld_lock.c
+++ b/libexec/rtld-elf/rtld_lock.c
@@ -316,3 +316,19 @@ _rtld_thread_init(struct RtldLockInfo *pli)
 	thread_mask_set(flags);
 	dbg("_rtld_thread_init: done");
 }
+
+void
+_rtld_atfork_pre(int *locks)
+{
+
+	locks[2] = wlock_acquire(rtld_phdr_lock);
+	locks[0] = rlock_acquire(rtld_bind_lock);
+}
+
+void
+_rtld_atfork_post(int *locks)
+{
+
+	rlock_release(rtld_bind_lock, locks[0]);
+	wlock_release(rtld_phdr_lock, locks[2]);
+}
diff --git a/libexec/rtld-elf/rtld_lock.h b/libexec/rtld-elf/rtld_lock.h
index 2e3f95422720..4c5d8541b3ea 100644
--- a/libexec/rtld-elf/rtld_lock.h
+++ b/libexec/rtld-elf/rtld_lock.h
@@ -44,6 +44,8 @@ struct RtldLockInfo
 };
 
 extern void _rtld_thread_init(struct RtldLockInfo *);
+extern void _rtld_atfork_pre(int *);
+extern void _rtld_atfork_post(int *);
 
 #ifdef IN_RTLD