From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752290Ab2HMMcW (ORCPT ); Mon, 13 Aug 2012 08:32:22 -0400 Received: from mailhub.sw.ru ([195.214.232.25]:19677 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751890Ab2HMMcU (ORCPT ); Mon, 13 Aug 2012 08:32:20 -0400 Subject: [PATCH v4 2/9] ipc: "use key as id" functionality for resource get system call introduced To: akpm@linux-foundation.org From: Stanislav Kinsbursky Cc: manfred@colorfullife.com, a.p.zijlstra@chello.nl, arnd@arndb.de, hughd@google.com, linux-kernel@vger.kernel.org, cmetcalf@tilera.com, yeohc@au1.ibm.com, linux-security-module@vger.kernel.org, kosaki.motohiro@jp.fujitsu.com, hpa@zytor.com, casey@schaufler-ca.com, eparis@parisplace.org, devel@openvz.org Date: Mon, 13 Aug 2012 16:31:42 +0400 Message-ID: <20120813123142.5581.69968.stgit@localhost6.localdomain6> In-Reply-To: <20120813122835.5581.70057.stgit@localhost6.localdomain6> References: <20120813122835.5581.70057.stgit@localhost6.localdomain6> User-Agent: StGit/0.15 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch introduces new IPC resource get request flag IPC_PRESET, which should be interpreted as a request to try to allocate IPC slot with number, starting from value resented by key. IOW, kernel will try allocate new segment in specified slot. If slot is not emply, them -EEXIST returned. Signed-off-by: Stanislav Kinsbursky Signed-off-by: Cyrill Gorcunov --- include/linux/ipc.h | 1 + ipc/msg.c | 1 + ipc/sem.c | 1 + ipc/shm.c | 1 + ipc/util.c | 8 +++++++- ipc/util.h | 1 + 6 files changed, 12 insertions(+), 1 deletions(-) diff --git a/include/linux/ipc.h b/include/linux/ipc.h index 30e8161..d7e5632 100644 --- a/include/linux/ipc.h +++ b/include/linux/ipc.h @@ -24,6 +24,7 @@ struct ipc_perm #define IPC_CREAT 00001000 /* create if key is nonexistent */ #define IPC_EXCL 00002000 /* fail if key exists */ #define IPC_NOWAIT 00004000 /* return error on wait */ +#define IPC_PRESET 00040000 /* use key as id */ /* these fields are used by the DIPC package so the kernel as standard should avoid using them if possible */ diff --git a/ipc/msg.c b/ipc/msg.c index f3bfbb8..70939a0 100644 --- a/ipc/msg.c +++ b/ipc/msg.c @@ -190,6 +190,7 @@ static int newque(struct ipc_namespace *ns, struct ipc_params *params) msq->q_perm.mode = msgflg & S_IRWXUGO; msq->q_perm.key = key; + msq->q_perm.id = (msgflg & IPC_PRESET) ? key : 0; msq->q_perm.security = NULL; retval = security_msg_queue_alloc(msq); diff --git a/ipc/sem.c b/ipc/sem.c index 5215a81..845c912 100644 --- a/ipc/sem.c +++ b/ipc/sem.c @@ -306,6 +306,7 @@ static int newary(struct ipc_namespace *ns, struct ipc_params *params) sma->sem_perm.mode = (semflg & S_IRWXUGO); sma->sem_perm.key = key; + sma->sem_perm.id = (semflg & IPC_PRESET) ? key : 0; sma->sem_perm.security = NULL; retval = security_sem_alloc(sma); diff --git a/ipc/shm.c b/ipc/shm.c index 41c1285..d4c0a9e 100644 --- a/ipc/shm.c +++ b/ipc/shm.c @@ -480,6 +480,7 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params) shp->shm_perm.key = key; shp->shm_perm.mode = (shmflg & S_IRWXUGO); + shp->shm_perm.id = (shmflg & IPC_PRESET) ? key : 0; shp->mlock_user = NULL; shp->shm_perm.security = NULL; diff --git a/ipc/util.c b/ipc/util.c index 75261a3..ac9c6a9 100644 --- a/ipc/util.c +++ b/ipc/util.c @@ -264,7 +264,8 @@ int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size) rcu_read_lock(); spin_lock(&new->lock); - err = idr_get_new(&ids->ipcs_idr, new, &id); + err = idr_get_new_above(&ids->ipcs_idr, new, + ipcid_to_idx(new->id), &id); if (err) { spin_unlock(&new->lock); rcu_read_unlock(); @@ -277,6 +278,11 @@ int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size) new->cuid = new->uid = euid; new->gid = new->cgid = egid; + if (new->id && ipcid_to_idx(new->id) == id) { + new->seq = ipcid_to_seq(new->id); + return id; + } + new->seq = ids->seq++; if(ids->seq > ids->seq_max) ids->seq = 0; diff --git a/ipc/util.h b/ipc/util.h index 6f5c20b..5f04b02 100644 --- a/ipc/util.h +++ b/ipc/util.h @@ -92,6 +92,7 @@ void __init ipc_init_proc_interface(const char *path, const char *header, #define IPC_SHM_IDS 2 #define ipcid_to_idx(id) ((id) % SEQ_MULTIPLIER) +#define ipcid_to_seq(id) ((id) / SEQ_MULTIPLIER) /* must be called with ids->rw_mutex acquired for writing */ int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int);