From 473afa3b7e826063b66e579cfbebaa99ee4602ab Mon Sep 17 00:00:00 2001
From: Ian Moffett <ian@osmora.org>
Date: Mon, 6 Oct 2025 21:52:49 -0400
Subject: lib: libc: Add SYS_open system call interface

Signed-off-by: Ian Moffett <ian@osmora.org>
---
 src/lib/libc/include/unistd.h  | 10 +++++++++
 src/lib/libc/src/unistd/open.c | 46 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 56 insertions(+)
 create mode 100644 src/lib/libc/src/unistd/open.c

diff --git a/src/lib/libc/include/unistd.h b/src/lib/libc/include/unistd.h
index b50fc12..fa7f951 100644
--- a/src/lib/libc/include/unistd.h
+++ b/src/lib/libc/include/unistd.h
@@ -37,6 +37,16 @@
 #define STDOUT_FILENO   1
 #define STDERR_FILENO   2
 
+/*
+ * POSIX open system call
+ *
+ * @path: Path to open
+ * @flags: O_ flags
+ *
+ * Returns the file descriptor on success
+ */
+int open(const char *path, int flags);
+
 /*
  * POSIX write system call
  *
diff --git a/src/lib/libc/src/unistd/open.c b/src/lib/libc/src/unistd/open.c
new file mode 100644
index 0000000..b8eca60
--- /dev/null
+++ b/src/lib/libc/src/unistd/open.c
@@ -0,0 +1,46 @@
+/*
+ * 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/syscall.h>
+#include <sys/errno.h>
+#include <unistd.h>
+
+int
+open(const char *path, int flags)
+{
+    if (path == NULL) {
+        return -EINVAL;
+    }
+
+    return syscall(
+        SYS_open,
+        (uintptr_t)path,
+        flags
+    );
+}
-- 
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