X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=ipc%2Fsem.c;h=e803abec2b086941103271bd010b8b37e554b18f;hb=8f4a3809c18ff3107bdbb1fabe3f4e5d2a928321;hp=45c7e573c2016f2da63ee6437a6f763ccbc24bca;hpb=f4566f04854d78acfc74b9acb029744acde9d033;p=safe%2Fjmp%2Flinux-2.6 diff --git a/ipc/sem.c b/ipc/sem.c index 45c7e573..e803abe 100644 --- a/ipc/sem.c +++ b/ipc/sem.c @@ -80,24 +80,20 @@ #include #include #include -#include +#include #include +#include #include #include "util.h" -#define sem_ids(ns) (*((ns)->ids[IPC_SEM_IDS])) +#define sem_ids(ns) ((ns)->ids[IPC_SEM_IDS]) #define sem_unlock(sma) ipc_unlock(&(sma)->sem_perm) -#define sem_checkid(ns, sma, semid) \ - ipc_checkid(&sem_ids(ns),&sma->sem_perm,semid) -#define sem_buildid(ns, id, seq) \ - ipc_buildid(&sem_ids(ns), id, seq) - -static struct ipc_ids init_sem_ids; +#define sem_checkid(sma, semid) ipc_checkid(&sma->sem_perm, semid) static int newary(struct ipc_namespace *, struct ipc_params *); -static void freeary(struct ipc_namespace *, struct sem_array *); +static void freeary(struct ipc_namespace *, struct kern_ipc_perm *); #ifdef CONFIG_PROC_FS static int sysvipc_sem_proc_show(struct seq_file *s, void *it); #endif @@ -119,65 +115,57 @@ static int sysvipc_sem_proc_show(struct seq_file *s, void *it); #define sc_semopm sem_ctls[2] #define sc_semmni sem_ctls[3] -static void __sem_init_ns(struct ipc_namespace *ns, struct ipc_ids *ids) +void sem_init_ns(struct ipc_namespace *ns) { - ns->ids[IPC_SEM_IDS] = ids; ns->sc_semmsl = SEMMSL; ns->sc_semmns = SEMMNS; ns->sc_semopm = SEMOPM; ns->sc_semmni = SEMMNI; ns->used_sems = 0; - ipc_init_ids(ids); -} - -int sem_init_ns(struct ipc_namespace *ns) -{ - struct ipc_ids *ids; - - ids = kmalloc(sizeof(struct ipc_ids), GFP_KERNEL); - if (ids == NULL) - return -ENOMEM; - - __sem_init_ns(ns, ids); - return 0; + ipc_init_ids(&ns->ids[IPC_SEM_IDS]); } +#ifdef CONFIG_IPC_NS void sem_exit_ns(struct ipc_namespace *ns) { - struct sem_array *sma; - int next_id; - int total, in_use; - - mutex_lock(&sem_ids(ns).mutex); - - in_use = sem_ids(ns).in_use; - - for (total = 0, next_id = 0; total < in_use; next_id++) { - sma = idr_find(&sem_ids(ns).ipcs_idr, next_id); - if (sma == NULL) - continue; - ipc_lock_by_ptr(&sma->sem_perm); - freeary(ns, sma); - total++; - } - mutex_unlock(&sem_ids(ns).mutex); - - kfree(ns->ids[IPC_SEM_IDS]); - ns->ids[IPC_SEM_IDS] = NULL; + free_ipcs(ns, &sem_ids(ns), freeary); } +#endif void __init sem_init (void) { - __sem_init_ns(&init_ipc_ns, &init_sem_ids); + sem_init_ns(&init_ipc_ns); ipc_init_proc_interface("sysvipc/sem", " key semid perms nsems uid gid cuid cgid otime ctime\n", IPC_SEM_IDS, sysvipc_sem_proc_show); } +/* + * This routine is called in the paths where the rw_mutex is held to protect + * access to the idr tree. + */ +static inline struct sem_array *sem_lock_check_down(struct ipc_namespace *ns, + int id) +{ + struct kern_ipc_perm *ipcp = ipc_lock_check_down(&sem_ids(ns), id); + + if (IS_ERR(ipcp)) + return (struct sem_array *)ipcp; + + return container_of(ipcp, struct sem_array, sem_perm); +} + +/* + * sem_lock_(check_) routines are called in the paths where the rw_mutex + * is not held. + */ static inline struct sem_array *sem_lock(struct ipc_namespace *ns, int id) { struct kern_ipc_perm *ipcp = ipc_lock(&sem_ids(ns), id); + if (IS_ERR(ipcp)) + return (struct sem_array *)ipcp; + return container_of(ipcp, struct sem_array, sem_perm); } @@ -186,9 +174,31 @@ static inline struct sem_array *sem_lock_check(struct ipc_namespace *ns, { struct kern_ipc_perm *ipcp = ipc_lock_check(&sem_ids(ns), id); + if (IS_ERR(ipcp)) + return (struct sem_array *)ipcp; + return container_of(ipcp, struct sem_array, sem_perm); } +static inline void sem_lock_and_putref(struct sem_array *sma) +{ + ipc_lock_by_ptr(&sma->sem_perm); + ipc_rcu_putref(sma); +} + +static inline void sem_getref_and_unlock(struct sem_array *sma) +{ + ipc_rcu_getref(sma); + ipc_unlock(&(sma)->sem_perm); +} + +static inline void sem_putref(struct sem_array *sma) +{ + ipc_lock_by_ptr(&sma->sem_perm); + ipc_rcu_putref(sma); + ipc_unlock(&(sma)->sem_perm); +} + static inline void sem_rmid(struct ipc_namespace *ns, struct sem_array *s) { ipc_rmid(&sem_ids(ns), &s->sem_perm); @@ -233,7 +243,7 @@ static inline void sem_rmid(struct ipc_namespace *ns, struct sem_array *s) * @ns: namespace * @params: ptr to the structure that contains key, semflg and nsems * - * Called with sem_ids.mutex held + * Called with sem_ids.rw_mutex held (as a writer) */ static int newary(struct ipc_namespace *ns, struct ipc_params *params) @@ -269,14 +279,13 @@ static int newary(struct ipc_namespace *ns, struct ipc_params *params) } id = ipc_addid(&sem_ids(ns), &sma->sem_perm, ns->sc_semmni); - if(id == -1) { + if (id < 0) { security_sem_free(sma); ipc_rcu_putref(sma); - return -ENOSPC; + return id; } ns->used_sems += nsems; - sma->sem_perm.id = sem_buildid(ns, id, sma->sem_perm.seq); sma->sem_base = (struct sem *) &sma[1]; /* sma->sem_pending = NULL; */ sma->sem_pending_last = &sma->sem_pending; @@ -290,7 +299,7 @@ static int newary(struct ipc_namespace *ns, struct ipc_params *params) /* - * Called with sem_ids.mutex and ipcp locked. + * Called with sem_ids.rw_mutex and ipcp locked. */ static inline int sem_security(struct kern_ipc_perm *ipcp, int semflg) { @@ -301,7 +310,7 @@ static inline int sem_security(struct kern_ipc_perm *ipcp, int semflg) } /* - * Called with sem_ids.mutex and ipcp locked. + * Called with sem_ids.rw_mutex and ipcp locked. */ static inline int sem_more_checks(struct kern_ipc_perm *ipcp, struct ipc_params *params) @@ -528,14 +537,15 @@ static int count_semzcnt (struct sem_array * sma, ushort semnum) return semzcnt; } -/* Free a semaphore set. freeary() is called with sem_ids.mutex locked and - * the spinlock for this semaphore set hold. sem_ids.mutex remains locked - * on exit. +/* Free a semaphore set. freeary() is called with sem_ids.rw_mutex locked + * as a writer and the spinlock for this semaphore set hold. sem_ids.rw_mutex + * remains locked on exit. */ -static void freeary(struct ipc_namespace *ns, struct sem_array *sma) +static void freeary(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp) { struct sem_undo *un; struct sem_queue *q; + struct sem_array *sma = container_of(ipcp, struct sem_array, sem_perm); /* Invalidate the existing undo structures for this semaphore set. * (They will be freed without any further action in exit_sem() @@ -589,8 +599,8 @@ static unsigned long copy_semid_to_user(void __user *buf, struct semid64_ds *in, } } -static int semctl_nolock(struct ipc_namespace *ns, int semid, int semnum, - int cmd, int version, union semun arg) +static int semctl_nolock(struct ipc_namespace *ns, int semid, + int cmd, int version, union semun arg) { int err = -EINVAL; struct sem_array *sma; @@ -615,7 +625,7 @@ static int semctl_nolock(struct ipc_namespace *ns, int semid, int semnum, seminfo.semmnu = SEMMNU; seminfo.semmap = SEMMAP; seminfo.semume = SEMUME; - mutex_lock(&sem_ids(ns).mutex); + down_read(&sem_ids(ns).rw_mutex); if (cmd == SEM_INFO) { seminfo.semusz = sem_ids(ns).in_use; seminfo.semaem = ns->used_sems; @@ -624,19 +634,28 @@ static int semctl_nolock(struct ipc_namespace *ns, int semid, int semnum, seminfo.semaem = SEMAEM; } max_id = ipc_get_maxid(&sem_ids(ns)); - mutex_unlock(&sem_ids(ns).mutex); + up_read(&sem_ids(ns).rw_mutex); if (copy_to_user (arg.__buf, &seminfo, sizeof(struct seminfo))) return -EFAULT; return (max_id < 0) ? 0: max_id; } + case IPC_STAT: case SEM_STAT: { struct semid64_ds tbuf; int id; - sma = sem_lock(ns, semid); - if (IS_ERR(sma)) - return PTR_ERR(sma); + if (cmd == SEM_STAT) { + sma = sem_lock(ns, semid); + if (IS_ERR(sma)) + return PTR_ERR(sma); + id = sma->sem_perm.id; + } else { + sma = sem_lock_check(ns, semid); + if (IS_ERR(sma)) + return PTR_ERR(sma); + id = 0; + } err = -EACCES; if (ipcperms (&sma->sem_perm, S_IRUGO)) @@ -646,8 +665,6 @@ static int semctl_nolock(struct ipc_namespace *ns, int semid, int semnum, if (err) goto out_unlock; - id = sma->sem_perm.id; - memset(&tbuf, 0, sizeof(tbuf)); kernel_to_ipc64_perm(&sma->sem_perm, &tbuf.sem_perm); @@ -700,19 +717,15 @@ static int semctl_main(struct ipc_namespace *ns, int semid, int semnum, int i; if(nsems > SEMMSL_FAST) { - ipc_rcu_getref(sma); - sem_unlock(sma); + sem_getref_and_unlock(sma); sem_io = ipc_alloc(sizeof(ushort)*nsems); if(sem_io == NULL) { - ipc_lock_by_ptr(&sma->sem_perm); - ipc_rcu_putref(sma); - sem_unlock(sma); + sem_putref(sma); return -ENOMEM; } - ipc_lock_by_ptr(&sma->sem_perm); - ipc_rcu_putref(sma); + sem_lock_and_putref(sma); if (sma->sem_perm.deleted) { sem_unlock(sma); err = -EIDRM; @@ -733,38 +746,30 @@ static int semctl_main(struct ipc_namespace *ns, int semid, int semnum, int i; struct sem_undo *un; - ipc_rcu_getref(sma); - sem_unlock(sma); + sem_getref_and_unlock(sma); if(nsems > SEMMSL_FAST) { sem_io = ipc_alloc(sizeof(ushort)*nsems); if(sem_io == NULL) { - ipc_lock_by_ptr(&sma->sem_perm); - ipc_rcu_putref(sma); - sem_unlock(sma); + sem_putref(sma); return -ENOMEM; } } if (copy_from_user (sem_io, arg.array, nsems*sizeof(ushort))) { - ipc_lock_by_ptr(&sma->sem_perm); - ipc_rcu_putref(sma); - sem_unlock(sma); + sem_putref(sma); err = -EFAULT; goto out_free; } for (i = 0; i < nsems; i++) { if (sem_io[i] > SEMVMX) { - ipc_lock_by_ptr(&sma->sem_perm); - ipc_rcu_putref(sma); - sem_unlock(sma); + sem_putref(sma); err = -ERANGE; goto out_free; } } - ipc_lock_by_ptr(&sma->sem_perm); - ipc_rcu_putref(sma); + sem_lock_and_putref(sma); if (sma->sem_perm.deleted) { sem_unlock(sma); err = -EIDRM; @@ -782,19 +787,6 @@ static int semctl_main(struct ipc_namespace *ns, int semid, int semnum, err = 0; goto out_unlock; } - case IPC_STAT: - { - struct semid64_ds tbuf; - memset(&tbuf,0,sizeof(tbuf)); - kernel_to_ipc64_perm(&sma->sem_perm, &tbuf.sem_perm); - tbuf.sem_otime = sma->sem_otime; - tbuf.sem_ctime = sma->sem_ctime; - tbuf.sem_nsems = sma->sem_nsems; - sem_unlock(sma); - if (copy_semid_to_user (arg.buf, &tbuf, version)) - return -EFAULT; - return 0; - } /* GETVAL, GETPID, GETNCTN, GETZCNT, SETVAL: fall-through */ } err = -EINVAL; @@ -843,28 +835,14 @@ out_free: return err; } -struct sem_setbuf { - uid_t uid; - gid_t gid; - mode_t mode; -}; - -static inline unsigned long copy_semid_from_user(struct sem_setbuf *out, void __user *buf, int version) +static inline unsigned long +copy_semid_from_user(struct semid64_ds *out, void __user *buf, int version) { switch(version) { case IPC_64: - { - struct semid64_ds tbuf; - - if(copy_from_user(&tbuf, buf, sizeof(tbuf))) + if (copy_from_user(out, buf, sizeof(*out))) return -EFAULT; - - out->uid = tbuf.sem_perm.uid; - out->gid = tbuf.sem_perm.gid; - out->mode = tbuf.sem_perm.mode; - return 0; - } case IPC_OLD: { struct semid_ds tbuf_old; @@ -872,9 +850,9 @@ static inline unsigned long copy_semid_from_user(struct sem_setbuf *out, void __ if(copy_from_user(&tbuf_old, buf, sizeof(tbuf_old))) return -EFAULT; - out->uid = tbuf_old.sem_perm.uid; - out->gid = tbuf_old.sem_perm.gid; - out->mode = tbuf_old.sem_perm.mode; + out->sem_perm.uid = tbuf_old.sem_perm.uid; + out->sem_perm.gid = tbuf_old.sem_perm.gid; + out->sem_perm.mode = tbuf_old.sem_perm.mode; return 0; } @@ -883,21 +861,29 @@ static inline unsigned long copy_semid_from_user(struct sem_setbuf *out, void __ } } -static int semctl_down(struct ipc_namespace *ns, int semid, int semnum, - int cmd, int version, union semun arg) +/* + * This function handles some semctl 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 semctl_down(struct ipc_namespace *ns, int semid, + int cmd, int version, union semun arg) { struct sem_array *sma; int err; - struct sem_setbuf uninitialized_var(setbuf); + struct semid64_ds semid64; struct kern_ipc_perm *ipcp; if(cmd == IPC_SET) { - if(copy_semid_from_user (&setbuf, arg.buf, version)) + if (copy_semid_from_user(&semid64, arg.buf, version)) return -EFAULT; } - sma = sem_lock_check(ns, semid); - if (IS_ERR(sma)) - return PTR_ERR(sma); + down_write(&sem_ids(ns).rw_mutex); + sma = sem_lock_check_down(ns, semid); + if (IS_ERR(sma)) { + err = PTR_ERR(sma); + goto out_up; + } ipcp = &sma->sem_perm; @@ -906,7 +892,9 @@ static int semctl_down(struct ipc_namespace *ns, int semid, int semnum, goto out_unlock; if (cmd == IPC_SET) { - err = audit_ipc_set_perm(0, setbuf.uid, setbuf.gid, setbuf.mode); + err = audit_ipc_set_perm(0, semid64.sem_perm.uid, + semid64.sem_perm.gid, + semid64.sem_perm.mode); if (err) goto out_unlock; } @@ -922,27 +910,20 @@ static int semctl_down(struct ipc_namespace *ns, int semid, int semnum, switch(cmd){ case IPC_RMID: - freeary(ns, sma); - err = 0; - break; + freeary(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); + ipc_update_perm(&semid64.sem_perm, ipcp); sma->sem_ctime = get_seconds(); - sem_unlock(sma); - err = 0; break; default: - sem_unlock(sma); err = -EINVAL; - break; } - return err; out_unlock: sem_unlock(sma); +out_up: + up_write(&sem_ids(ns).rw_mutex); return err; } @@ -961,60 +942,28 @@ asmlinkage long sys_semctl (int semid, int semnum, int cmd, union semun arg) switch(cmd) { case IPC_INFO: case SEM_INFO: + case IPC_STAT: case SEM_STAT: - err = semctl_nolock(ns,semid,semnum,cmd,version,arg); + err = semctl_nolock(ns, semid, cmd, version, arg); return err; case GETALL: case GETVAL: case GETPID: case GETNCNT: case GETZCNT: - case IPC_STAT: case SETVAL: case SETALL: err = semctl_main(ns,semid,semnum,cmd,version,arg); return err; case IPC_RMID: case IPC_SET: - mutex_lock(&sem_ids(ns).mutex); - err = semctl_down(ns,semid,semnum,cmd,version,arg); - mutex_unlock(&sem_ids(ns).mutex); + err = semctl_down(ns, semid, cmd, version, arg); return err; default: return -EINVAL; } } -static inline void lock_semundo(void) -{ - struct sem_undo_list *undo_list; - - undo_list = current->sysvsem.undo_list; - if (undo_list) - spin_lock(&undo_list->lock); -} - -/* This code has an interaction with copy_semundo(). - * Consider; two tasks are sharing the undo_list. task1 - * acquires the undo_list lock in lock_semundo(). If task2 now - * exits before task1 releases the lock (by calling - * unlock_semundo()), then task1 will never call spin_unlock(). - * This leave the sem_undo_list in a locked state. If task1 now creats task3 - * and once again shares the sem_undo_list, the sem_undo_list will still be - * locked, and future SEM_UNDO operations will deadlock. This case is - * dealt with in copy_semundo() by having it reinitialize the spin lock when - * the refcnt goes from 1 to 2. - */ -static inline void unlock_semundo(void) -{ - struct sem_undo_list *undo_list; - - undo_list = current->sysvsem.undo_list; - if (undo_list) - spin_unlock(&undo_list->lock); -} - - /* If the task doesn't already have a undo_list, then allocate one * here. We guarantee there is only one thread using this undo list, * and current is THE ONE @@ -1075,9 +1024,9 @@ static struct sem_undo *find_undo(struct ipc_namespace *ns, int semid) if (error) return ERR_PTR(error); - lock_semundo(); + spin_lock(&ulp->lock); un = lookup_undo(ulp, semid); - unlock_semundo(); + spin_unlock(&ulp->lock); if (likely(un!=NULL)) goto out; @@ -1087,34 +1036,28 @@ static struct sem_undo *find_undo(struct ipc_namespace *ns, int semid) return ERR_PTR(PTR_ERR(sma)); nsems = sma->sem_nsems; - ipc_rcu_getref(sma); - sem_unlock(sma); + sem_getref_and_unlock(sma); new = kzalloc(sizeof(struct sem_undo) + sizeof(short)*nsems, GFP_KERNEL); if (!new) { - ipc_lock_by_ptr(&sma->sem_perm); - ipc_rcu_putref(sma); - sem_unlock(sma); + sem_putref(sma); return ERR_PTR(-ENOMEM); } new->semadj = (short *) &new[1]; new->semid = semid; - lock_semundo(); + spin_lock(&ulp->lock); un = lookup_undo(ulp, semid); if (un) { - unlock_semundo(); + spin_unlock(&ulp->lock); kfree(new); - ipc_lock_by_ptr(&sma->sem_perm); - ipc_rcu_putref(sma); - sem_unlock(sma); + sem_putref(sma); goto out; } - ipc_lock_by_ptr(&sma->sem_perm); - ipc_rcu_putref(sma); + sem_lock_and_putref(sma); if (sma->sem_perm.deleted) { sem_unlock(sma); - unlock_semundo(); + spin_unlock(&ulp->lock); kfree(new); un = ERR_PTR(-EIDRM); goto out; @@ -1125,7 +1068,7 @@ static struct sem_undo *find_undo(struct ipc_namespace *ns, int semid) sma->undo = new; sem_unlock(sma); un = new; - unlock_semundo(); + spin_unlock(&ulp->lock); out: return un; } @@ -1301,10 +1244,6 @@ asmlinkage long sys_semop (int semid, struct sembuf __user *tsops, unsigned nsop /* If CLONE_SYSVSEM is set, establish sharing of SEM_UNDO state between * parent and child tasks. - * - * See the notes above unlock_semundo() regarding the spin_lock_init() - * in this code. Initialize the undo_list->lock here instead of get_undo_list() - * because of the reasoning in the comment above unlock_semundo. */ int copy_semundo(unsigned long clone_flags, struct task_struct *tsk) @@ -1370,7 +1309,7 @@ void exit_sem(struct task_struct *tsk) if (u->semid == -1) goto next_entry; - BUG_ON(sem_checkid(ns,sma,u->semid)); + BUG_ON(sem_checkid(sma, u->semid)); /* remove u from the sma->undo list */ for (unp = &sma->undo; (un = *unp); unp = &un->id_next) {