Re: [PATCH 3/3] ipc namespace: copy settings from parent namespace

From: Serge E. Hallyn
Date: Fri Jun 06 2014 - 09:57:44 EST


Quoting Michael Kerrisk (man-pages) (mtk.manpages@xxxxxxxxx):
> [CC += Eric and containers@]
>
> Hi Manfred,
>
> On Thu, May 29, 2014 at 8:46 PM, Manfred Spraul
> <manfred@xxxxxxxxxxxxxxxx> wrote:
> > Right now, each IPC namespace starts with the kernel boot standard
> > settings.
> > This patch changes that:
> > Now each new namespace starts with the settings from the parent
> > namespace.
> >
> > The patch updates
> > - SysV msg
> > - SysV sem
> > - SysV shm
> > - POSIX mqueues
> >
> > It's just a proposal - only partially tested
>
> This seems like a sane idea, but maybe the containers folk and Eric
> have some comments.

Looks good to me.

> Cheers,
>
> Michael
>
>
> > --
> > Manfred
> > ---
> > include/linux/ipc_namespace.h | 6 ++++--
> > ipc/mqueue.c | 23 ++++++++++++++++-------
> > ipc/msg.c | 16 +++++++++++-----
> > ipc/namespace.c | 6 +++---
> > ipc/sem.c | 19 +++++++++++++------
> > ipc/shm.c | 19 +++++++++++++------
> > ipc/util.h | 20 ++++++++++++++------
> > 7 files changed, 74 insertions(+), 35 deletions(-)
> >
> > diff --git a/include/linux/ipc_namespace.h b/include/linux/ipc_namespace.h
> > index e365d5e..1cc36a0 100644
> > --- a/include/linux/ipc_namespace.h
> > +++ b/include/linux/ipc_namespace.h
> > @@ -73,7 +73,7 @@ static inline void shm_destroy_orphaned(struct ipc_namespace *ns) {}
> > #endif /* CONFIG_SYSVIPC */
> >
> > #ifdef CONFIG_POSIX_MQUEUE
> > -extern int mq_init_ns(struct ipc_namespace *ns);
> > +extern int mq_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns);
> > /*
> > * POSIX Message Queue default values:
> > *
> > @@ -108,7 +108,9 @@ extern int mq_init_ns(struct ipc_namespace *ns);
> > #define DFLT_MSGSIZEMAX 8192
> > #define HARD_MSGSIZEMAX (16*1024*1024)
> > #else
> > -static inline int mq_init_ns(struct ipc_namespace *ns) { return 0; }
> > +static inline int mq_init_ns(struct ipc_namespace *ns,
> > + struct ipc_namespace *old_ns)
> > +{ return 0; }
> > #endif
> >
> > #if defined(CONFIG_IPC_NS)
> > diff --git a/ipc/mqueue.c b/ipc/mqueue.c
> > index 4fcf39a..3473072d 100644
> > --- a/ipc/mqueue.c
> > +++ b/ipc/mqueue.c
> > @@ -1397,14 +1397,23 @@ static struct file_system_type mqueue_fs_type = {
> > .fs_flags = FS_USERNS_MOUNT,
> > };
> >
> > -int mq_init_ns(struct ipc_namespace *ns)
> > +int mq_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns)
> > {
> > + if (old_ns != NULL) {
> > + ns->mq_queues_max = old_ns->mq_queues_max;
> > + ns->mq_msg_max = old_ns->mq_msg_max;
> > + ns->mq_msgsize_max = old_ns->mq_msgsize_max;
> > + ns->mq_msg_default = old_ns->mq_msg_default;
> > + ns->mq_msgsize_default = old_ns->mq_msgsize_default;
> > + } else {
> > + ns->mq_queues_max = DFLT_QUEUESMAX;
> > + ns->mq_msg_max = DFLT_MSGMAX;
> > + ns->mq_msgsize_max = DFLT_MSGSIZEMAX;
> > + ns->mq_msg_default = DFLT_MSG;
> > + ns->mq_msgsize_default = DFLT_MSGSIZE;
> > + }
> > +
> > ns->mq_queues_count = 0;
> > - ns->mq_queues_max = DFLT_QUEUESMAX;
> > - ns->mq_msg_max = DFLT_MSGMAX;
> > - ns->mq_msgsize_max = DFLT_MSGSIZEMAX;
> > - ns->mq_msg_default = DFLT_MSG;
> > - ns->mq_msgsize_default = DFLT_MSGSIZE;
> >
> > ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns);
> > if (IS_ERR(ns->mq_mnt)) {
> > @@ -1444,7 +1453,7 @@ static int __init init_mqueue_fs(void)
> >
> > spin_lock_init(&mq_lock);
> >
> > - error = mq_init_ns(&init_ipc_ns);
> > + error = mq_init_ns(&init_ipc_ns, NULL);
> > if (error)
> > goto out_filesystem;
> >
> > diff --git a/ipc/msg.c b/ipc/msg.c
> > index ea7e0d1..d457052 100644
> > --- a/ipc/msg.c
> > +++ b/ipc/msg.c
> > @@ -77,11 +77,17 @@ static int sysvipc_msg_proc_show(struct seq_file *s, void *it);
> > #endif
> >
> >
> > -void msg_init_ns(struct ipc_namespace *ns)
> > +void msg_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns)
> > {
> > - ns->msg_ctlmax = MSGMAX;
> > - ns->msg_ctlmnb = MSGMNB;
> > - ns->msg_ctlmni = MSGMNI;
> > + if (old_ns != NULL) {
> > + ns->msg_ctlmax = old_ns->msg_ctlmax;
> > + ns->msg_ctlmnb = old_ns->msg_ctlmnb;
> > + ns->msg_ctlmni = old_ns->msg_ctlmni;
> > + } else {
> > + ns->msg_ctlmax = MSGMAX;
> > + ns->msg_ctlmnb = MSGMNB;
> > + ns->msg_ctlmni = MSGMNI;
> > + }
> >
> > atomic_set(&ns->msg_bytes, 0);
> > atomic_set(&ns->msg_hdrs, 0);
> > @@ -98,7 +104,7 @@ void msg_exit_ns(struct ipc_namespace *ns)
> >
> > void __init msg_init(void)
> > {
> > - msg_init_ns(&init_ipc_ns);
> > + msg_init_ns(&init_ipc_ns, NULL);
> >
> > ipc_init_proc_interface("sysvipc/msg",
> > " key msqid perms cbytes qnum lspid lrpid uid gid cuid cgid stime rtime ctime\n",
> > diff --git a/ipc/namespace.c b/ipc/namespace.c
> > index 6c01c2a..33ee4be 100644
> > --- a/ipc/namespace.c
> > +++ b/ipc/namespace.c
> > @@ -41,9 +41,9 @@ static struct ipc_namespace *create_ipc_ns(struct user_namespace *user_ns,
> > }
> > atomic_inc(&nr_ipc_ns);
> >
> > - sem_init_ns(ns);
> > - msg_init_ns(ns);
> > - shm_init_ns(ns);
> > + sem_init_ns(ns, old_ns);
> > + msg_init_ns(ns, old_ns);
> > + shm_init_ns(ns, old_ns);
> >
> > ns->user_ns = get_user_ns(user_ns);
> >
> > diff --git a/ipc/sem.c b/ipc/sem.c
> > index bee5554..0e232e6 100644
> > --- a/ipc/sem.c
> > +++ b/ipc/sem.c
> > @@ -170,12 +170,19 @@ static int sysvipc_sem_proc_show(struct seq_file *s, void *it);
> > #define sc_semopm sem_ctls[2]
> > #define sc_semmni sem_ctls[3]
> >
> > -void sem_init_ns(struct ipc_namespace *ns)
> > +void sem_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns)
> > {
> > - ns->sc_semmsl = SEMMSL;
> > - ns->sc_semmns = SEMMNS;
> > - ns->sc_semopm = SEMOPM;
> > - ns->sc_semmni = SEMMNI;
> > + if (old_ns != NULL) {
> > + ns->sc_semmsl = old_ns->sc_semmsl;
> > + ns->sc_semmns = old_ns->sc_semmns;
> > + ns->sc_semopm = old_ns->sc_semopm;
> > + ns->sc_semmni = old_ns->sc_semmni;
> > + } else {
> > + ns->sc_semmsl = SEMMSL;
> > + ns->sc_semmns = SEMMNS;
> > + ns->sc_semopm = SEMOPM;
> > + ns->sc_semmni = SEMMNI;
> > + }
> > ns->used_sems = 0;
> > ipc_init_ids(&ns->ids[IPC_SEM_IDS]);
> > }
> > @@ -190,7 +197,7 @@ void sem_exit_ns(struct ipc_namespace *ns)
> >
> > void __init sem_init(void)
> > {
> > - sem_init_ns(&init_ipc_ns);
> > + sem_init_ns(&init_ipc_ns, NULL);
> > ipc_init_proc_interface("sysvipc/sem",
> > " key semid perms nsems uid gid cuid cgid otime ctime\n",
> > IPC_SEM_IDS, sysvipc_sem_proc_show);
> > diff --git a/ipc/shm.c b/ipc/shm.c
> > index 7645961..5c54b25 100644
> > --- a/ipc/shm.c
> > +++ b/ipc/shm.c
> > @@ -72,12 +72,19 @@ static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp);
> > static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
> > #endif
> >
> > -void shm_init_ns(struct ipc_namespace *ns)
> > +void shm_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns)
> > {
> > - ns->shm_ctlmax = SHMMAX;
> > - ns->shm_ctlall = SHMALL;
> > - ns->shm_ctlmni = SHMMNI;
> > - ns->shm_rmid_forced = 0;
> > + if (old_ns != NULL) {
> > + ns->shm_ctlmax = old_ns->shm_ctlmax;
> > + ns->shm_ctlall = old_ns->shm_ctlall;
> > + ns->shm_ctlmni = old_ns->shm_ctlmni;
> > + ns->shm_rmid_forced = old_ns->shm_rmid_forced;
> > + } else {
> > + ns->shm_ctlmax = SHMMAX;
> > + ns->shm_ctlall = SHMALL;
> > + ns->shm_ctlmni = SHMMNI;
> > + ns->shm_rmid_forced = 0;
> > + }
> > ns->shm_tot = 0;
> > ipc_init_ids(&shm_ids(ns));
> > }
> > @@ -110,7 +117,7 @@ void shm_exit_ns(struct ipc_namespace *ns)
> >
> > static int __init ipc_ns_init(void)
> > {
> > - shm_init_ns(&init_ipc_ns);
> > + shm_init_ns(&init_ipc_ns, NULL);
> > return 0;
> > }
> >
> > diff --git a/ipc/util.h b/ipc/util.h
> > index 9c47d6f..a66d8f2 100644
> > --- a/ipc/util.h
> > +++ b/ipc/util.h
> > @@ -30,17 +30,25 @@ static inline void mq_put_mnt(struct ipc_namespace *ns) { }
> > #endif
> >
> > #ifdef CONFIG_SYSVIPC
> > -void sem_init_ns(struct ipc_namespace *ns);
> > -void msg_init_ns(struct ipc_namespace *ns);
> > -void shm_init_ns(struct ipc_namespace *ns);
> > +void sem_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns);
> > +void msg_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns);
> > +void shm_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns);
> >
> > void sem_exit_ns(struct ipc_namespace *ns);
> > void msg_exit_ns(struct ipc_namespace *ns);
> > void shm_exit_ns(struct ipc_namespace *ns);
> > #else
> > -static inline void sem_init_ns(struct ipc_namespace *ns) { }
> > -static inline void msg_init_ns(struct ipc_namespace *ns) { }
> > -static inline void shm_init_ns(struct ipc_namespace *ns) { }
> > +static inline void sem_init_ns(struct ipc_namespace *ns,
> > + struct ipc_namespace *old_ns)
> > +{ }
> > +
> > +static inline void msg_init_ns(struct ipc_namespace *ns,
> > + struct ipc_namespace *old_ns)
> > +{ }
> > +
> > +static inline void shm_init_ns(struct ipc_namespace *ns,
> > + struct ipc_namespace *old_ns)
> > +{ }
> >
> > static inline void sem_exit_ns(struct ipc_namespace *ns) { }
> > static inline void msg_exit_ns(struct ipc_namespace *ns) { }
> > --
> > 1.9.3
> >
>
>
>
> --
> Michael Kerrisk
> Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
> Linux/UNIX System Programming Training: http://man7.org/training/
> _______________________________________________
> Containers mailing list
> Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx
> https://lists.linuxfoundation.org/mailman/listinfo/containers
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