The patch titled IPC/shared memory: introduce shmctl_down has been added to the -mm tree. Its filename is ipc-shared-memory-introduce-shmctl_down.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: IPC/shared memory: introduce shmctl_down From: Pierre Peiffer <pierre.peiffer@xxxxxxxx> Currently, the way the different commands are handled in sys_shmctl introduces some duplicated code. This patch introduces the shmctl_down function to handle all the commands requiring the rwmutex to be taken in write mode (ie IPC_SET and IPC_RMID for now). It is the equivalent function of semctl_down for shared memory. This removes some duplicated code for handling these both commands and harmonizes the way they are handled among all IPCs. Signed-off-by: Pierre Peiffer <pierre.peiffer@xxxxxxxx> Acked-by: Serge Hallyn <serue@xxxxxxxxxx> Cc: Nadia Derbey <Nadia.Derbey@xxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- ipc/shm.c | 160 +++++++++++++++++++++++----------------------------- 1 file changed, 72 insertions(+), 88 deletions(-) diff -puN ipc/shm.c~ipc-shared-memory-introduce-shmctl_down ipc/shm.c --- a/ipc/shm.c~ipc-shared-memory-introduce-shmctl_down +++ a/ipc/shm.c @@ -617,10 +617,78 @@ static void shm_get_stat(struct ipc_name } } -asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf) +/* + * This function handles some shmctl commands which require the rw_mutex + * to be held in write mode. + * NOTE: no locks must be held, the rw_mutex is taken inside this function. + */ +static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd, + struct shmid_ds __user *buf, int version) { + struct kern_ipc_perm *ipcp; struct shm_setbuf setbuf; struct shmid_kernel *shp; + int err; + + if (cmd == IPC_SET) { + if (copy_shmid_from_user(&setbuf, buf, version)) + return -EFAULT; + } + + down_write(&shm_ids(ns).rw_mutex); + shp = shm_lock_check_down(ns, shmid); + if (IS_ERR(shp)) { + err = PTR_ERR(shp); + goto out_up; + } + + ipcp = &shp->shm_perm; + + err = audit_ipc_obj(ipcp); + if (err) + goto out_unlock; + + if (cmd == IPC_SET) { + err = audit_ipc_set_perm(0, setbuf.uid, + setbuf.gid, setbuf.mode); + if (err) + goto out_unlock; + } + + if (current->euid != ipcp->uid && + current->euid != ipcp->cuid && + !capable(CAP_SYS_ADMIN)) { + err = -EPERM; + goto out_unlock; + } + + err = security_shm_shmctl(shp, cmd); + if (err) + goto out_unlock; + switch (cmd) { + case IPC_RMID: + do_shm_rmid(ns, ipcp); + goto out_up; + case IPC_SET: + ipcp->uid = setbuf.uid; + ipcp->gid = setbuf.gid; + ipcp->mode = (ipcp->mode & ~S_IRWXUGO) + | (setbuf.mode & S_IRWXUGO); + shp->shm_ctim = get_seconds(); + break; + default: + err = -EINVAL; + } +out_unlock: + shm_unlock(shp); +out_up: + up_write(&shm_ids(ns).rw_mutex); + return err; +} + +asmlinkage long sys_shmctl(int shmid, int cmd, struct shmid_ds __user *buf) +{ + struct shmid_kernel *shp; int err, version; struct ipc_namespace *ns; @@ -776,97 +844,13 @@ asmlinkage long sys_shmctl (int shmid, i goto out; } case IPC_RMID: - { - /* - * We cannot simply remove the file. The SVID states - * that the block remains until the last person - * detaches from it, then is deleted. A shmat() on - * an RMID segment is legal in older Linux and if - * we change it apps break... - * - * Instead we set a destroyed flag, and then blow - * the name away when the usage hits zero. - */ - down_write(&shm_ids(ns).rw_mutex); - shp = shm_lock_check_down(ns, shmid); - if (IS_ERR(shp)) { - err = PTR_ERR(shp); - goto out_up; - } - - err = audit_ipc_obj(&(shp->shm_perm)); - if (err) - goto out_unlock_up; - - if (current->euid != shp->shm_perm.uid && - current->euid != shp->shm_perm.cuid && - !capable(CAP_SYS_ADMIN)) { - err=-EPERM; - goto out_unlock_up; - } - - err = security_shm_shmctl(shp, cmd); - if (err) - goto out_unlock_up; - - do_shm_rmid(ns, &shp->shm_perm); - up_write(&shm_ids(ns).rw_mutex); - goto out; - } - case IPC_SET: - { - if (!buf) { - err = -EFAULT; - goto out; - } - - if (copy_shmid_from_user (&setbuf, buf, version)) { - err = -EFAULT; - goto out; - } - down_write(&shm_ids(ns).rw_mutex); - shp = shm_lock_check_down(ns, shmid); - if (IS_ERR(shp)) { - err = PTR_ERR(shp); - goto out_up; - } - err = audit_ipc_obj(&(shp->shm_perm)); - if (err) - goto out_unlock_up; - err = audit_ipc_set_perm(0, setbuf.uid, setbuf.gid, setbuf.mode); - if (err) - goto out_unlock_up; - err=-EPERM; - if (current->euid != shp->shm_perm.uid && - current->euid != shp->shm_perm.cuid && - !capable(CAP_SYS_ADMIN)) { - goto out_unlock_up; - } - - err = security_shm_shmctl(shp, cmd); - if (err) - goto out_unlock_up; - - shp->shm_perm.uid = setbuf.uid; - shp->shm_perm.gid = setbuf.gid; - shp->shm_perm.mode = (shp->shm_perm.mode & ~S_IRWXUGO) - | (setbuf.mode & S_IRWXUGO); - shp->shm_ctim = get_seconds(); - break; - } - + err = shmctl_down(ns, shmid, cmd, buf, version); + return err; default: - err = -EINVAL; - goto out; + return -EINVAL; } - err = 0; -out_unlock_up: - shm_unlock(shp); -out_up: - up_write(&shm_ids(ns).rw_mutex); - goto out; out_unlock: shm_unlock(shp); out: _ Patches currently in -mm which might be from pierre.peiffer@xxxxxxxx are origin.patch ipc-use-ipc_buildid-directly-from-ipc_addid.patch ipc-use-ipc_buildid-directly-from-ipc_addid-cleanup.patch ipc-scale-msgmni-to-the-amount-of-lowmem.patch ipc-scale-msgmni-to-the-number-of-ipc-namespaces.patch ipc-define-the-slab_memory_callback-priority-as-a-constant.patch ipc-recompute-msgmni-on-memory-add--remove.patch ipc-invoke-the-ipcns-notifier-chain-as-a-work-item.patch ipc-recompute-msgmni-on-ipc-namespace-creation-removal.patch ipc-do-not-recompute-msgmni-anymore-if-explicitly-set-by-user.patch ipc-re-enable-msgmni-automatic-recomputing-msgmni-if-set-to-negative.patch ipc-semaphores-code-factorisation.patch ipc-shared-memory-introduce-shmctl_down.patch ipc-message-queues-introduce-msgctl_down.patch ipc-semaphores-move-the-rwmutex-handling-inside-semctl_down.patch ipc-semaphores-remove-one-unused-parameter-from-semctl_down.patch ipc-get-rid-of-the-use-_setbuf-structure.patch ipc-introduce-ipc_update_perm.patch ipc-consolidate-all-xxxctl_down-functions.patch - To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html