diff options
| author | Lucas De Marchi <lucas.demarchi@profusion.mobi> | 2011-11-02 13:39:22 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-11-02 16:07:02 -0700 |
| commit | f1ecf06854a66ee663f4d4cf029c78cd62a15e04 (patch) | |
| tree | cbe863057fa14b9390746db6d2b1812a2f874b48 /include/linux/sysctl.h | |
| 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 'include/linux/sysctl.h')
| -rw-r--r-- | include/linux/sysctl.h | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h index 9a1ec10fd50..703cfa33a3c 100644 --- a/include/linux/sysctl.h +++ b/include/linux/sysctl.h @@ -931,6 +931,7 @@ enum #ifdef __KERNEL__ #include <linux/list.h> #include <linux/rcupdate.h> +#include <linux/wait.h> /* For the /proc/sys support */ struct ctl_table; @@ -1011,6 +1012,26 @@ extern int proc_do_large_bitmap(struct ctl_table *, int, * cover common cases. */ +/* Support for userspace poll() to watch for changes */ +struct ctl_table_poll { + atomic_t event; + wait_queue_head_t wait; +}; + +static inline void *proc_sys_poll_event(struct ctl_table_poll *poll) +{ + return (void *)(unsigned long)atomic_read(&poll->event); +} + +void proc_sys_poll_notify(struct ctl_table_poll *poll); + +#define __CTL_TABLE_POLL_INITIALIZER(name) { \ + .event = ATOMIC_INIT(0), \ + .wait = __WAIT_QUEUE_HEAD_INITIALIZER(name.wait) } + +#define DEFINE_CTL_TABLE_POLL(name) \ + struct ctl_table_poll name = __CTL_TABLE_POLL_INITIALIZER(name) + /* A sysctl table is an array of struct ctl_table: */ struct ctl_table { @@ -1021,6 +1042,7 @@ struct ctl_table struct ctl_table *child; struct ctl_table *parent; /* Automatically set */ proc_handler *proc_handler; /* Callback for text formatting */ + struct ctl_table_poll *poll; void *extra1; void *extra2; }; |