From: Masatake YAMATO <[email protected]> Date: Thu, 30 Aug 2012 05:44:29 +0900
> lsof reports some of socket descriptors as "can't identify protocol" like: > > [yamato@localhost]/tmp% sudo lsof | grep dbus | grep iden > dbus-daem 652 dbus 6u sock ... 17812 can't identify > protocol > dbus-daem 652 dbus 34u sock ... 24689 can't identify > protocol > dbus-daem 652 dbus 42u sock ... 24739 can't identify > protocol > dbus-daem 652 dbus 48u sock ... 22329 can't identify > protocol > ... > > lsof cannot resolve the protocol used in a socket because procfs > doesn't provide the map between inode number on sockfs and protocol > type of the socket. > > For improving the situation this patch adds an extended attribute named > 'system.sockprotoname' in which the protocol name for > /proc/PID/fd/SOCKET is stored. So lsof can know the protocol for a > given /proc/PID/fd/SOCKET with getxattr system call. > > A few weeks ago I submitted a patch for the same purpose. The patch > was introduced /proc/net/sockfs which enumerates inodes and protocols > of all sockets alive on a system. However, it was rejected because (1) > a global lock was needed, and (2) the layout of struct socket was > changed with the patch. > > This patch doesn't use any global lock; and doesn't change the layout > of any structs. > > In this patch, a protocol name is stored to dentry->d_name of sockfs > when new socket is associated with a file descriptor. Before this > patch dentry->d_name was not used; it was just filled with empty > string. lsof may use an extended attribute named > 'system.sockprotoname' to retrieve the value of dentry->d_name. > > It is nice if we can see the protocol name with ls -l > /proc/PID/fd. However, "socket:[#INODE]", the name format returned > from sockfs_dname() was already defined. To keep the compatibility > between kernel and user land, the extended attribute is used to > prepare the value of dentry->d_name. > > Signed-off-by: Masatake YAMATO <[email protected]> This looks a lot more reasonable than your previous attempt. Applied to net-next, thanks a lot. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
