diff options
| author | Lucas De Marchi | 2011-11-02 13:39:22 -0700 |
|---|---|---|
| committer | Linus Torvalds | 2011-11-02 16:07:02 -0700 |
| commit | f1ecf06854a66ee663f4d4cf029c78cd62a15e04 (patch) | |
| tree | cbe863057fa14b9390746db6d2b1812a2f874b48 /fs | |
| parent | 088024b1deee206cd37eff980138e918837aabdb (diff) | |
sysctl: add support for poll()
Adding support for poll() in sysctl fs allows userspace to receive
notifications of changes in sysctl entries. This adds a infrastructure to
allow files in sysctl fs to be pollable and implements it for hostname and
domainname.
[akpm@linux-foundation.org: s/declare/define/ for definitions]
Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
Cc: Greg KH <gregkh@suse.de>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/proc/proc_sysctl.c | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c index dacd840a675a..df594803f45a 100644 --- a/fs/proc/proc_sysctl.c +++ b/fs/proc/proc_sysctl.c @@ -3,6 +3,7 @@ */ #include <linux/init.h> #include <linux/sysctl.h> +#include <linux/poll.h> #include <linux/proc_fs.h> #include <linux/security.h> #include <linux/namei.h> @@ -14,6 +15,15 @@ static const struct inode_operations proc_sys_inode_operations; static const struct file_operations proc_sys_dir_file_operations; static const struct inode_operations proc_sys_dir_operations; +void proc_sys_poll_notify(struct ctl_table_poll *poll) +{ + if (!poll) + return; + + atomic_inc(&poll->event); + wake_up_interruptible(&poll->wait); +} + static struct inode *proc_sys_make_inode(struct super_block *sb, struct ctl_table_header *head, struct ctl_table *table) { @@ -176,6 +186,39 @@ static ssize_t proc_sys_write(struct file *filp, const char __user *buf, return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 1); } +static int proc_sys_open(struct inode *inode, struct file *filp) +{ + struct ctl_table *table = PROC_I(inode)->sysctl_entry; + + if (table->poll) + filp->private_data = proc_sys_poll_event(table->poll); + + return 0; +} + +static unsigned int proc_sys_poll(struct file *filp, poll_table *wait) +{ + struct inode *inode = filp->f_path.dentry->d_inode; + struct ctl_table *table = PROC_I(inode)->sysctl_entry; + unsigned long event = (unsigned long)filp->private_data; + unsigned int ret = DEFAULT_POLLMASK; + + if (!table->proc_handler) + goto out; + + if (!table->poll) + goto out; + + poll_wait(filp, &table->poll->wait, wait); + + if (event != atomic_read(&table->poll->event)) { + filp->private_data = proc_sys_poll_event(table->poll); + ret = POLLIN | POLLRDNORM | POLLERR | POLLPRI; + } + +out: + return ret; +} static int proc_sys_fill_cache(struct file *filp, void *dirent, filldir_t filldir, @@ -364,6 +407,8 @@ static int proc_sys_getattr(struct vfsmount *mnt, struct dentry *dentry, struct } static const struct file_operations proc_sys_file_operations = { + .open = proc_sys_open, + .poll = proc_sys_poll, .read = proc_sys_read, .write = proc_sys_write, .llseek = default_llseek, |