libc: unistd: Add close system call interface

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

2 files changed, 49 insertions, 0 deletions

diff --git a/src/lib/libc/include/unistd.h b/src/lib/libc/include/unistd.h
index d2c32b6..b668d5b 100644
--- a/src/lib/libc/include/unistd.h
+++ b/src/lib/libc/include/unistd.h
@@ -48,6 +48,15 @@
 int open(const char *path, int flags);
 
 /*
+ * Close a file using its file descriptor
+ *
+ * @fd: File descriptor to close
+ *
+ * Returns zero on success
+ */
+int close(int fd);
+
+/*
  * POSIX write system call
  *
  * @fd: File descriptor to write at
diff --git a/src/lib/libc/src/unistd/close.c b/src/lib/libc/src/unistd/close.c
new file mode 100644
index 0000000..125bba0
--- /dev/null
+++ b/src/lib/libc/src/unistd/close.c
@@ -0,0 +1,40 @@
+/*
+ * 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 <unistd.h>
+
+int
+close(int fd)
+{
+    return syscall(
+        SYS_close,
+        fd
+    );
+}