Re: [PATCH 1/8] /proc/net/ entries for bluetooth protocols

[Andrei Emeltchenko]

Hi Masatake,

small nitpicks

On Fri, Jun 15, 2012 at 02:15:53AM +0900, Masatake YAMATO wrote:
> lsof command can tell the type of socket processes are using. Internally
> lsof uses inode numbers on socket fs as key to resolve the type of
> sockets. Files under /proc/net/, such as tcp, udp, unix, etc provides
> such inode information.
> 
> Unfortunately bluetooth related protocols don't provide such inode
> information. This patch series introduces /proc/net/* files for the protocols.
> 
> 
> This patch against af_bluetooth.c provides facility to the implementation
> of protocols. This patch extends bt_sock_list and introduces two exported
> function bt_procfs_init, bt_procfs_cleanup.
> 
> The type bt_sock_list is already used in some implementations of
> protocols. bt_procfs_init prepares seq_operations which converts
> protocol own bt_sock_list data to /proc/net proc entry for the
> protocol when the entry is accessed by cat or something process.
> 
> What I, lsof user, need is just inode number of bluetooth
> socket. Therefore default show handler of seq_operations
> prints bluetooth socket common informations including inode
> number.
> 
> However, people may want more information. The bt_procfs_init
> takes a function pointer for customizing the show handler of
> seq_operations.
> 
> Signed-off-by: Masatake YAMATO <yamato@xxxxxxxxxx>
> ---
>  include/net/bluetooth/bluetooth.h |   12 ++++
>  net/bluetooth/af_bluetooth.c      |  136 +++++++++++++++++++++++++++++++++++++
>  2 files changed, 148 insertions(+)
> 
> diff --git a/include/net/bluetooth/bluetooth.h b/include/net/bluetooth/bluetooth.h
> index 961669b..83a1d1a 100644
> --- a/include/net/bluetooth/bluetooth.h
> +++ b/include/net/bluetooth/bluetooth.h
> @@ -30,6 +30,9 @@
>  #include <linux/list.h>
>  #include <linux/poll.h>
>  #include <net/sock.h>
> +#include <linux/seq_file.h>
> +
> +
>  

Too much spaces here!

>  #ifndef AF_BLUETOOTH
>  #define AF_BLUETOOTH	31
> @@ -205,6 +208,10 @@ enum {
>  struct bt_sock_list {
>  	struct hlist_head head;
>  	rwlock_t          lock;
> +#ifdef CONFIG_PROC_FS
> +        struct file_operations   fops;
> +        int (* custom_seq_show)(struct seq_file *, void *);
> +#endif
>  };
>  
>  int  bt_sock_register(int proto, const struct net_proto_family *ops);
> @@ -293,6 +300,11 @@ extern void hci_sock_cleanup(void);
>  extern int bt_sysfs_init(void);
>  extern void bt_sysfs_cleanup(void);
>  
> +extern int  bt_procfs_init(struct module* module, struct net *net, const char *name, 
> +			   struct bt_sock_list* sk_list,
> +			   int (* seq_show)(struct seq_file *, void *));
> +extern void bt_procfs_cleanup(struct net *net, const char *name);
> +
>  extern struct dentry *bt_debugfs;
>  
>  int l2cap_init(void);
> diff --git a/net/bluetooth/af_bluetooth.c b/net/bluetooth/af_bluetooth.c
> index 46e7f86..81a2094 100644
> --- a/net/bluetooth/af_bluetooth.c
> +++ b/net/bluetooth/af_bluetooth.c
> @@ -542,6 +543,141 @@ int bt_sock_wait_state(struct sock *sk, int state, unsigned long timeo)
>  }
>  EXPORT_SYMBOL(bt_sock_wait_state);
>  
> +#ifdef CONFIG_PROC_FS
> +struct bt_seq_state {
> +	struct bt_sock_list *l;
> +};
> +
> +static void *bt_seq_start(struct seq_file *seq, loff_t *pos)
> +{
> +	struct bt_seq_state *s = seq->private;
> +	
> +	read_lock(&s->l->lock);
> +	return seq_hlist_start_head(&s->l->head, *pos);

maybe define s->l as a local variable?

> +}
> +
> +static void *bt_seq_next(struct seq_file *seq, void *v, loff_t *pos)
> +{
> +	struct bt_seq_state *s = seq->private;
> +	
> +	return seq_hlist_next(v, &s->l->head, pos);
> +}
> +
> +static void bt_seq_stop(struct seq_file *seq, void *v)
> +{
> +	struct bt_seq_state *s = seq->private;
> +
> +	read_unlock(&s->l->lock);
> +}
> +
> +static int bt_seq_show(struct seq_file *seq, void *v)
> +{
> +	struct sock *sk;
> +	struct bt_sock *bt;
> +	struct bt_seq_state *s = seq->private;
> +
> +
> +	if (v == SEQ_START_TOKEN) {
> +		seq_puts(seq ,"sk              RefCnt Rmem   Wmem   User   Inode Src Dst Parent");
> +
> +		if (s->l->custom_seq_show) {
> +			seq_putc(seq, ' ');
> +			s->l->custom_seq_show(seq, v);
> +		}
> +
> +		seq_putc(seq, '\n');
> +	}
> +	else {

shall be "} else {"

> +		sk = sk_entry(v);
> +		bt = bt_sk(sk);
> +		seq_printf(seq, "%pK %-6d %-6u %-6u %-6u %-6lu",
> +			   sk,
> +			   atomic_read(&sk->sk_refcnt),
> +			   sk_rmem_alloc_get(sk),
> +			   sk_wmem_alloc_get(sk),
> +			   sock_i_uid(sk),
> +			   sock_i_ino(sk)
> +			);
> +		seq_puts(seq, batostr(&bt->src));

batostr looks OK now but this will be outdated soon by %pMR.

> +		seq_putc(seq, ' ');
> +		seq_puts(seq, batostr(&bt->dst));
> +		seq_putc(seq, ' ');
> +		seq_printf(seq, "%-6lu", bt->parent? sock_i_ino(bt->parent): 0LU);
> +
> +		if (s->l->custom_seq_show) {
> +			seq_putc(seq, ' ');
> +			s->l->custom_seq_show(seq, v);
> +		}
> +
> +		seq_putc(seq, '\n');
> +	}
> +	return 0;
> +}
> +
> +static struct seq_operations bt_seq_ops = {
> +	.start = bt_seq_start,
> +	.next  = bt_seq_next,
> +	.stop  = bt_seq_stop,
> +	.show  = bt_seq_show,
> +};
> +
> +static int bt_seq_open(struct inode *inode, struct file *file)
> +{
> +	struct bt_sock_list *sk_list;
> +	struct bt_seq_state *s;
> +
> +	sk_list = PDE(inode)->data;
> +	s = __seq_open_private(file, &bt_seq_ops,
> +			       sizeof(struct bt_seq_state));
> +	if (s == NULL)
> +		return -ENOMEM;
> +	 
> +	s->l = sk_list;
> +	return 0;
> +}
> +
> +int bt_procfs_init(struct module* module, struct net *net, const char *name, struct bt_sock_list* sk_list,
> +		   int (* seq_show)(struct seq_file *, void *))
> +{
> +	struct proc_dir_entry * pde;
> +
> +	sk_list->custom_seq_show = seq_show;
> +
> +	sk_list->fops.owner     = module;
> +	sk_list->fops.open      = bt_seq_open;
> +	sk_list->fops.read      = seq_read;
> +	sk_list->fops.llseek    = seq_lseek;
> +	sk_list->fops.release   = seq_release_private;
> +	
> +	pde = proc_net_fops_create(net, name, 0, &sk_list->fops);
> +	if (pde == NULL)
> +		return -ENOMEM;
> +
> +	pde->data = sk_list;
> +	
> +	return 0;
> +}
> +
> +void bt_procfs_cleanup(struct net *net, const char *name)
> +{
> +	proc_net_remove(net, name);
> +}
> +#else
> +int bt_procfs_init(struct module* module, struct net *net, const char *name, struct bt_sock_list* sk_list,
> +		   int (* seq_show)(struct seq_file *, void *))
> +{
> +	return 0;
> +}
> +
> +void bt_procfs_cleanup(struct net *net, const char *name)
> +{
> +}
> +#endif
> +
> +EXPORT_SYMBOL(bt_procfs_init);
> +EXPORT_SYMBOL(bt_procfs_cleanup);
> +
> +

too much spaces

>  static struct net_proto_family bt_sock_family_ops = {
>  	.owner	= THIS_MODULE,
>  	.family	= PF_BLUETOOTH,
> -- 
> 1.7.10.2

Best regards 
Andrei Emeltchenko 
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