linux/ipc
Stanislav Kinsbursky 4a674f34ba ipc: introduce message queue copy feature
This patch is required for checkpoint/restore in userspace.

c/r requires some way to get all pending IPC messages without deleting
them from the queue (checkpoint can fail and in this case tasks will be
resumed, so queue have to be valid).

To achive this, new operation flag MSG_COPY for sys_msgrcv() system call
was introduced.  If this flag was specified, then mtype is interpreted as
number of the message to copy.

If MSG_COPY is set, then kernel will allocate dummy message with passed
size, and then use new copy_msg() helper function to copy desired message
(instead of unlinking it from the queue).

Notes:

1) Return -ENOSYS if MSG_COPY is specified, but
   CONFIG_CHECKPOINT_RESTORE is not set.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Cc: Serge Hallyn <serge.hallyn@canonical.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-01-04 16:11:45 -08:00
..
compat_mq.c ipc: initialize structure memory to zero for compat functions 2010-10-27 18:03:13 -07:00
compat.c ipc: message queue receive cleanup 2013-01-04 16:11:45 -08:00
ipc_sysctl.c ipc: add sysctl to specify desired next object id 2013-01-04 16:11:45 -08:00
ipcns_notifier.c ipc: do not use a negative value to re-enable msgmni automatic recomputing 2008-07-25 10:53:42 -07:00
Makefile Add generic sys_ipc wrapper 2010-03-12 15:52:32 -08:00
mq_sysctl.c mqueue: separate mqueue default value from maximum value 2012-05-31 17:49:31 -07:00
mqueue.c audit: make audit_inode take struct filename 2012-10-12 20:15:09 -04:00
msg.c ipc: introduce message queue copy feature 2013-01-04 16:11:45 -08:00
msgutil.c ipc: introduce message queue copy feature 2013-01-04 16:11:45 -08:00
namespace.c userns: Require CAP_SYS_ADMIN for most uses of setns. 2012-12-14 16:12:03 -08:00
sem.c userns: Convert ipc to use kuid and kgid where appropriate 2012-09-06 22:17:20 -07:00
shm.c mm: support more pagesizes for MAP_HUGETLB/SHM_HUGETLB 2012-12-11 17:22:25 -08:00
syscall.c ipc: add COMPAT_SHMLBA support 2012-07-30 17:25:20 -07:00
util.c ipc: add sysctl to specify desired next object id 2013-01-04 16:11:45 -08:00
util.h ipc: introduce message queue copy feature 2013-01-04 16:11:45 -08:00