The semaphores are restored by creating each 'sem object read from the checkpoint image. Each semaphore array (sem->sem_base) is checked for validity of contents before copies to the corresponding semaphore.
TODO: this patch does not handle semaphore-undo -- this data should be restored per-task while iterating through the tasks. Signed-off-by: Oren Laadan <[email protected]> --- ipc/checkpoint.c | 2 - ipc/checkpoint_sem.c | 116 ++++++++++++++++++++++++++++++++++++++++++++++++++ ipc/util.h | 3 + 3 files changed, 119 insertions(+), 2 deletions(-) diff --git a/ipc/checkpoint.c b/ipc/checkpoint.c index 7a2f4a5..e14dea6 100644 --- a/ipc/checkpoint.c +++ b/ipc/checkpoint.c @@ -213,12 +213,10 @@ static int do_restore_ipc_ns(struct ckpt_ctx *ctx) goto out; ret = restore_ipc_any(ctx, IPC_MSG_IDS, CKPT_HDR_IPC_MSG, restore_ipc_msg); -#if 0 /* NEXT FEW PATCHES */ if (ret < 0) goto out; ret = restore_ipc_any(ctx, IPC_SEM_IDS, CKPT_HDR_IPC_SEM, restore_ipc_sem); -#endif out: ckpt_hdr_put(ctx, h); return ret; diff --git a/ipc/checkpoint_sem.c b/ipc/checkpoint_sem.c index fc6ea44..0065202 100644 --- a/ipc/checkpoint_sem.c +++ b/ipc/checkpoint_sem.c @@ -99,3 +99,119 @@ int checkpoint_ipc_sem(int id, void *p, void *data) ckpt_hdr_put(ctx, h); return ret; } + +/************************************************************************ + * ipc restart + */ + +static int load_ipc_sem_hdr(struct ckpt_ctx *ctx, + struct ckpt_hdr_ipc_sem *h, + struct sem_array *sem) +{ + int ret = 0; + + ret = restore_load_ipc_perms(&h->perms, &sem->sem_perm); + if (ret < 0) + return ret; + + ckpt_debug("sem: nsems %u\n", h->sem_nsems); + + sem->sem_otime = h->sem_otime; + sem->sem_ctime = h->sem_ctime; + sem->sem_nsems = h->sem_nsems; + + return 0; +} + +/** + * ckpt_read_sem_array - read the state of a semaphore array + * @ctx: checkpoint context + * @sem: semphore array + * + * Expect the data in an array of 'struct sem': {32 bit, 32 bit}. + * See comment in ckpt_write_sem_array(). + * + * The sem-undo information is not restored per ipc_ns, but rather per task. + */ +static struct sem *restore_sem_array(struct ckpt_ctx *ctx, int nsems) +{ + struct sem *sma; + int i, ret; + + sma = kmalloc(nsems * sizeof(*sma), GFP_KERNEL); + ret = _ckpt_read_buffer(ctx, sma, nsems * sizeof(*sma)); + if (ret < 0) + goto out; + + /* validate sem array contents */ + for (i = 0; i < nsems; i++) { + if (sma[i].semval < 0 || sma[i].sempid < 0) { + ret = -EINVAL; + break; + } + } + out: + if (ret < 0) { + kfree(sma); + sma = ERR_PTR(ret); + } + return sma; +} + +int restore_ipc_sem(struct ckpt_ctx *ctx) +{ + struct ckpt_hdr_ipc_sem *h; + struct kern_ipc_perm *perms; + struct sem_array *sem; + struct sem *sma = NULL; + struct ipc_ids *sem_ids = ¤t->nsproxy->ipc_ns->ids[IPC_SEM_IDS]; + int semflag, ret; + + h = ckpt_read_obj_type(ctx, sizeof(*h), CKPT_HDR_IPC_SEM); + if (IS_ERR(h)) + return PTR_ERR(h); + + ret = -EINVAL; + if (h->perms.id < 0) + goto out; + if (h->sem_nsems < 0) + goto out; + + /* read sempahore array state */ + sma = restore_sem_array(ctx, h->sem_nsems); + if (IS_ERR(sma)) { + ret = PTR_ERR(sma); + goto out; + } + + /* restore the message queue now */ + semflag = h->perms.mode | IPC_CREAT | IPC_EXCL; + ckpt_debug("sem: do_semget key %d flag %#x id %d\n", + h->perms.key, semflag, h->perms.id); + ret = do_semget(h->perms.key, h->sem_nsems, semflag, h->perms.id); + ckpt_debug("sem: do_msgget ret %d\n", ret); + if (ret < 0) + goto out; + + down_write(&sem_ids->rw_mutex); + + /* we are the sole owners/users of this ipc_ns, it can't go away */ + perms = ipc_lock(sem_ids, h->perms.id); + BUG_ON(IS_ERR(perms)); /* ipc_ns is private to us */ + + sem = container_of(perms, struct sem_array, sem_perm); + memcpy(sem->sem_base, sma, sem->sem_nsems * sizeof(*sma)); + + ret = load_ipc_sem_hdr(ctx, h, sem); + ipc_unlock(perms); + + if (ret < 0) { + ckpt_debug("sem: need to remove (%d)\n", ret); + freeary(current->nsproxy->ipc_ns, perms); + } + up_write(&sem_ids->rw_mutex); + out: + kfree(sma); + ckpt_hdr_put(ctx, h); + return ret; +} diff --git a/ipc/util.h b/ipc/util.h index 5b7cead..54f9acb 100644 --- a/ipc/util.h +++ b/ipc/util.h @@ -184,6 +184,8 @@ int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids, /* for checkpoint/restart */ extern int do_shmget(key_t key, size_t size, int shmflg, int req_id); extern int do_msgget(key_t key, int msgflg, int req_id); +extern int do_semget(key_t key, int nsems, int semflg, int req_id); + extern void freeque(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp); extern void freeary(struct ipc_namespace *, struct kern_ipc_perm *); @@ -202,6 +204,7 @@ extern int checkpoint_ipc_msg(int id, void *p, void *data); extern int restore_ipc_msg(struct ckpt_ctx *ctx); extern int checkpoint_ipc_sem(int id, void *p, void *data); +extern int restore_ipc_sem(struct ckpt_ctx *ctx); #endif #endif -- 1.5.4.3 _______________________________________________ Containers mailing list [email protected] https://lists.linux-foundation.org/mailman/listinfo/containers _______________________________________________ Devel mailing list [email protected] https://openvz.org/mailman/listinfo/devel
