net: Allow to show socket-specific information in /proc/[pid]/fdinfo/[fd]

This adds .show_fdinfo to socket_file_ops, so protocols will be able
to print their specific data in fdinfo.

Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/net.h b/include/linux/net.h
index 9cafb5f..6451425 100644 (file)
--- a/include/linux/net.h
+++ b/include/linux/net.h
@@ -171,6 +171,7 @@ struct proto_ops {
        int             (*compat_getsockopt)(struct socket *sock, int level,
                                      int optname, char __user *optval, int __user *optlen);
 #endif
+       void            (*show_fdinfo)(struct seq_file *m, struct socket *sock);
        int             (*sendmsg)   (struct socket *sock, struct msghdr *m,
                                      size_t total_len);
        /* Notes for implementing recvmsg:

diff --git a/net/socket.c b/net/socket.c
index 4d38d49..532f123 100644 (file)
--- a/net/socket.c
+++ b/net/socket.c
@@ -128,6 +128,7 @@ static ssize_t sock_sendpage(struct file *file, struct page *page,
 static ssize_t sock_splice_read(struct file *file, loff_t *ppos,
                                struct pipe_inode_info *pipe, size_t len,
                                unsigned int flags);
+static void sock_show_fdinfo(struct seq_file *m, struct file *f);
 
 /*
  *     Socket files have a set of 'special' operations as well as the generic file ones. These don't appear
@@ -150,6 +151,9 @@ static const struct file_operations socket_file_ops = {
        .sendpage =     sock_sendpage,
        .splice_write = generic_splice_sendpage,
        .splice_read =  sock_splice_read,
+#ifdef CONFIG_PROC_FS
+       .show_fdinfo =  sock_show_fdinfo,
+#endif
 };
 
 /*
@@ -993,6 +997,14 @@ static ssize_t sock_write_iter(struct kiocb *iocb, struct iov_iter *from)
        return res;
 }
 
+static void sock_show_fdinfo(struct seq_file *m, struct file *f)
+{
+       struct socket *sock = f->private_data;
+
+       if (sock->ops->show_fdinfo)
+               sock->ops->show_fdinfo(m, sock);
+}
+
 /*
  * Atomic setting of ioctl hooks to avoid race
  * with module unload.