1 files changed, 95 insertions, 0 deletions
diff --git a/sys/kern/kern_subr.c b/sys/kern/kern_subr.c
new file mode 100644
index 0000000..dd1a618
--- /dev/null
+++ b/sys/kern/kern_subr.c
@@ -0,0 +1,95 @@
+/*
+ * Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team.
+ * 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 Hyra 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/system.h>
+#include <sys/types.h>
+#include <sys/errno.h>
+#include <sys/sched.h>
+#include <vm/vm.h>
+#include <string.h>
+
+/*
+ * Check if a user address is valid.
+ *
+ * @uaddr: User address to check.
+ *
+ * Returns true if valid, otherwise false.
+ */
+static bool
+check_uaddr(uintptr_t uaddr)
+{
+    struct proc *td = this_td();
+    struct vm_range exec_range = td->addr_range[ADDR_RANGE_EXEC];
+    struct vm_range stack_range = td->addr_range[ADDR_RANGE_STACK];
+
+    if (uaddr >= exec_range.start && uaddr <= exec_range.end) {
+        return true;
+    }
+    if (uaddr >= stack_range.start && uaddr <= stack_range.end) {
+        return true;
+    }
+
+    return false;
+}
+
+/*
+ * Copy from userspace to the kernel.
+ *
+ * @uaddr: Userspace address.
+ * @kaddr: Kernelspace address.
+ * @len: Length of data.
+ */
+int
+copyin(uintptr_t uaddr, void *kaddr, size_t len)
+{
+    if (!check_uaddr(uaddr) || !check_uaddr(uaddr + len)) {
+        return -EFAULT;
+    }
+
+    memcpy(kaddr, (void *)uaddr, len);
+    return 0;
+}
+
+/*
+ * Copy from the kernel to userspace.
+ *
+ * @kaddr: Kernelspace address.
+ * @uaddr: Userspace address.
+ * @len: Length of data.
+ */
+int
+copyout(const void *kaddr, uintptr_t uaddr, size_t len)
+{
+    if (!check_uaddr(uaddr) || !check_uaddr(uaddr + len)) {
+        return -EFAULT;
+    }
+
+    memcpy((void *)uaddr, kaddr, len);
+    return 0;
+}