[PATCH] CONNECTOR: add a proc entry to list connectors

From: Li Zefan
Date: Mon Jun 23 2008 - 21:32:34 EST


I got a problem when I wanted to check if the kernel supports process
event connector, and It seems there's no way to do this check.

At best I can check if the kernel supports connector or not, by looking
into /proc/net/netlink, or maybe checking the return value of bind() to
see if it's ENOENT.

So how about add /proc/net/connector to list all supported connectors?
# cat /proc/net/connector
Name ID
connector 4294967295:4294967295
cn_proc 1:1
w1 3:1

Signed-off-by: Li Zefan <lizf@xxxxxxxxxxxxxx>
---
drivers/connector/connector.c | 41 +++++++++++++++++++++++++++++++++++++++++
1 files changed, 41 insertions(+), 0 deletions(-)

diff --git a/drivers/connector/connector.c b/drivers/connector/connector.c
index 85e2ba7..08f9983 100644
--- a/drivers/connector/connector.c
+++ b/drivers/connector/connector.c
@@ -27,6 +27,8 @@
#include <linux/moduleparam.h>
#include <linux/connector.h>
#include <linux/mutex.h>
+#include <linux/proc_fs.h>
+#include <linux/spinlock.h>

#include <net/sock.h>

@@ -403,6 +405,41 @@ static void cn_callback(void *data)
mutex_unlock(&notify_lock);
}

+static int cn_proc_show(struct seq_file *m, void *v)
+{
+ struct cn_queue_dev *dev = cdev.cbdev;
+ struct cn_callback_entry *cbq;
+ unsigned long flags;
+
+ seq_printf(m, "Name ID\n");
+
+ spin_lock_irqsave(&dev->queue_lock, flags);
+
+ list_for_each_entry(cbq, &dev->queue_list, callback_entry) {
+ seq_printf(m, "%-9s %u:%u\n",
+ cbq->id.name,
+ cbq->id.id.idx,
+ cbq->id.id.val);
+ }
+
+ spin_unlock_irqrestore(&dev->queue_lock, flags);
+
+ return 0;
+}
+
+static int cn_proc_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, cn_proc_show, NULL);
+}
+
+static const struct file_operations cn_file_ops = {
+ .owner = THIS_MODULE,
+ .open = cn_proc_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release
+};
+
static int __devinit cn_init(void)
{
struct cn_dev *dev = &cdev;
@@ -434,6 +471,8 @@ static int __devinit cn_init(void)
return -EINVAL;
}

+ proc_net_fops_create(&init_net, "connector", S_IRUGO, &cn_file_ops);
+
return 0;
}

@@ -443,6 +482,8 @@ static void __devexit cn_fini(void)

cn_already_initialized = 0;

+ proc_net_remove(&init_net, "connector");
+
cn_del_callback(&dev->id);
cn_queue_free_dev(dev->cbdev);
netlink_kernel_release(dev->nls);
--
1.5.4.rc3

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