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>

2 files changed, 66 insertions, 6 deletions

diff --git a/src/sys/include/os/mac.h b/src/sys/include/os/mac.h
index f6e2514..c896cc6 100644
--- a/src/sys/include/os/mac.h
+++ b/src/sys/include/os/mac.h
@@ -31,17 +31,12 @@
 #define _OS_MAC_H_ 1
 
 #include <sys/types.h>
+#include <sys/mac.h>
 
 /* Forward declarations */
 struct mac_border;
 struct proc;
 
-typedef enum {
-    BORDER_NONE,
-    BORDER_FBDEV,
-    __BORDER_MAX
-} border_id_t;
-
 /*
  * MAC levels
  *
diff --git a/src/sys/include/sys/mac.h b/src/sys/include/sys/mac.h
new file mode 100644
index 0000000..4bd46c0
--- /dev/null
+++ b/src/sys/include/sys/mac.h
@@ -0,0 +1,65 @@
+/*
+ * 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.
+ */
+
+#ifndef _SYS_MAC_H_
+#define _SYS_MAC_H_ 1
+
+#include <sys/types.h>
+#ifndef _KERNEL
+#include <stdint.h>
+#include <stddef.h>
+#endif  /* !_KERNEL */
+
+typedef enum {
+    BORDER_NONE,
+    BORDER_FBDEV,
+    __BORDER_MAX
+} border_id_t;
+
+#ifndef _KERNEL
+
+/*
+ * Cross a resource border via MAC
+ *
+ * @id: ID of resource border to cross
+ * @length: Length of resource
+ * @off: Resource offset to request
+ * @flags: Optional flags
+ * @res: Result pointer is written here
+ *
+ * Returns the resource length on success, otherwise a less
+ * than zero value on failure.
+ */
+ssize_t cross(
+    border_id_t id, size_t length, off_t off,
+    int flags, void *res
+);
+
+#endif  /* _KERNEL */
+#endif  /* !_SYS_MAC_H_ */