libc: Add resource border crossing interface

Introduce a new libc cross() function which acts as a wrapper to the
SYS_cross system call.

Signed-off-by: Ian Moffett <ian@osmora.org>

1 files changed, 55 insertions, 0 deletions

diff --git a/src/lib/libc/src/l5/cross.c b/src/lib/libc/src/l5/cross.c
new file mode 100644
index 0000000..397715e
--- /dev/null
+++ b/src/lib/libc/src/l5/cross.c
@@ -0,0 +1,55 @@
+/*
+ * Copyright (c) 2025 Ian Marco Moffett and L5 engineers
+ * 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.
+ * 3. Neither the name of the project nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT OWNER OR CONTRIBUTORS 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.
+ */
+
+#include <sys/types.h>
+#include <sys/syscall.h>
+#include <sys/errno.h>
+#include <sys/mac.h>
+#include <stdint.h>
+#include <stddef.h>
+
+/*
+ * Cross a resource border
+ */
+ssize_t
+cross(border_id_t id, size_t length, off_t off, int flags, void *res)
+{
+    if (res == NULL || length == 0) {
+        return -EINVAL;
+    }
+
+    if (id == BORDER_NONE) {
+        return -EINVAL;
+    }
+
+    return syscall(
+        SYS_cross, id, length,
+        off, flags, (uintptr_t)res
+    );
+}