feat(uio): readv/writev

src/uio/writev.c

@@ -0,0 +1,21 @@
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <sys/uio.h>
+
+#include "../internal/syscall.h"
+
+/*
+ * writev: gather write — the kernel writes the iovcnt buffers of iov in
+ * order and returns the total byte count. The iovec array is passed straight
+ * to SYS_writev: no argument validation here, the kernel applies its own
+ * rules (iovcnt 0..IOV_MAX, iov NULL with iovcnt > 0 faults as EFAULT). The
+ * raw result goes through syscall_ret(), which returns the count on success
+ * and -1 with errno set on error; errno is untouched on success.
+ */
+ssize_t
+writev(int fd, const struct iovec *iov, int iovcnt)
+{
+    return syscall_ret(__syscall3(SYS_writev, fd, (long)iov, (long)iovcnt));
+}