sendfile() is a system call which streamlines the copying of data between the disk and the tcp socket. The call copied from the page cache directly rather than requiring a kernel -> user space -> kernel space copy for every read() and write() call. Generally the advantages are only felt on heavily loaded servers. The call is supported in ProFTPD for Linux and FreeBSD.

Linux 2.0.x

sendfile is not supported under 2.0.x, this is not an issue when compiling for 2.0.x on a 2.0.x system. However when compiling on a 2.2.x system for use on 2.0.x use the --disable-sendfile flag.

Runtime detection of sendfile()

There are two patches available for runtime detection of sendfile() which gets round the 2.0.x problems.

Johnie Ingram (aka netgod)'s:

John Pierce <>

What are these log lines in pre8?

The pre8 code has some additional debug logging going on tracking how sendfile is working. Nothing to get excited about it's probably a case of MacGyver forgetting to comment it out.