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 | |
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')
-rw-r--r-- | include/linux/sysctl.h | 22 | ||||
-rw-r--r-- | include/linux/utsname.h | 16 |
2 files changed, 38 insertions, 0 deletions
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h index 9a1ec10fd504..703cfa33a3ca 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; }; diff --git a/include/linux/utsname.h b/include/linux/utsname.h index 4e5b0213fdc1..c714ed75eae2 100644 --- a/include/linux/utsname.h +++ b/include/linux/utsname.h @@ -37,6 +37,14 @@ struct new_utsname { #include <linux/nsproxy.h> #include <linux/err.h> +enum uts_proc { + UTS_PROC_OSTYPE, + UTS_PROC_OSRELEASE, + UTS_PROC_VERSION, + UTS_PROC_HOSTNAME, + UTS_PROC_DOMAINNAME, +}; + struct user_namespace; extern struct user_namespace init_user_ns; @@ -80,6 +88,14 @@ static inline struct uts_namespace *copy_utsname(unsigned long flags, } #endif +#ifdef CONFIG_PROC_SYSCTL +extern void uts_proc_notify(enum uts_proc proc); +#else +static inline void uts_proc_notify(enum uts_proc proc) +{ +} +#endif + static inline struct new_utsname *utsname(void) { return ¤t->nsproxy->uts_ns->name; |