usr: libc: Add lseek()

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

2 files changed, 44 insertions, 0 deletions

diff --git a/lib/libc/include/unistd.h b/lib/libc/include/unistd.h
index 2da4ee0..70908c8 100644
--- a/lib/libc/include/unistd.h
+++ b/lib/libc/include/unistd.h
@@ -36,12 +36,19 @@
 
 #define F_OK 0
 
+/* lseek whence, follows Hyra ABI */
+#define SEEK_SET 0
+#define SEEK_CUR 1
+#define SEEK_END 2
+
 __BEGIN_DECLS
 
 ssize_t read(int fd, void *buf, size_t count);
 ssize_t write(int fd, const void *buf, size_t count);
+
 int close(int fd);
 int access(const char *path, int mode);
+off_t lseek(int fildes, off_t offset, int whence);
 
 __END_DECLS
 
diff --git a/lib/libc/src/unistd/lseek.c b/lib/libc/src/unistd/lseek.c
new file mode 100644
index 0000000..d99b0f0
--- /dev/null
+++ b/lib/libc/src/unistd/lseek.c
@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2023-2025 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/syscall.h>
+#include <unistd.h>
+
+off_t
+lseek(int fildes, off_t offset, int whence)
+{
+    return syscall(SYS_lseek, fildes, offset, whence);
+}