1 files changed, 94 insertions, 0 deletions
diff --git a/libexec/rtld-elf/i386/lockdflt.c b/libexec/rtld-elf/i386/lockdflt.c
new file mode 100644
index 0000000..6f278c3
--- /dev/null
+++ b/libexec/rtld-elf/i386/lockdflt.c
@@ -0,0 +1,94 @@
+/*-
+ * Copyright 1999 John D. Polstra.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+/*
+ * Default thread locking implementation for the dynamic linker.  It
+ * is used until the client registers a different implementation with
+ * dllockinit().  The default implementation does mutual exclusion
+ * by blocking the SIGVTALRM, SIGPROF, and SIGALRM signals.  This is
+ * based on the observation that most userland thread packages use one
+ * of these signals to support preemption.
+ */
+
+#include <dlfcn.h>
+#include <signal.h>
+#include <stdlib.h>
+
+#include "debug.h"
+#include "rtld.h"
+
+typedef struct Struct_LockDflt {
+    sigset_t lock_mask;
+    sigset_t old_mask;
+    int depth;
+} LockDflt;
+
+void
+lockdflt_acquire(void *lock)
+{
+    LockDflt *l = (LockDflt *)lock;
+    sigprocmask(SIG_BLOCK, &l->lock_mask, &l->old_mask);
+    assert(l->depth == 0);
+    l->depth++;
+}
+
+void *
+lockdflt_create(void *context)
+{
+    LockDflt *l;
+
+    l = NEW(LockDflt);
+    l->depth = 0;
+    sigemptyset(&l->lock_mask);
+    sigaddset(&l->lock_mask, SIGVTALRM);
+    sigaddset(&l->lock_mask, SIGPROF);
+    sigaddset(&l->lock_mask, SIGALRM);
+    return l;
+}
+
+void
+lockdflt_destroy(void *lock)
+{
+    LockDflt *l = (LockDflt *)lock;
+    free(l);
+}
+
+void
+lockdflt_release(void *lock)
+{
+    LockDflt *l = (LockDflt *)lock;
+    assert(l->depth == 1);
+    l->depth--;
+    sigprocmask(SIG_SETMASK, &l->old_mask, NULL);
+}
+
+void
+lockdflt_init(void)
+{
+    dllockinit(NULL, lockdflt_create, lockdflt_acquire, lockdflt_acquire,
+      lockdflt_release, lockdflt_destroy, NULL);
+}