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ipc/sem.c
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/* * linux/ipc/sem.c * Copyright (C) 1992 Krishna Balasubramanian * Copyright (C) 1995 Eric Schenk, Bruno Haible * |
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* /proc/sysvipc/sem support (c) 1999 Dragos Acostachioaie <dragos@iname.com> * * SMP-threaded, sysctl's added |
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* (c) 1999 Manfred Spraul <manfred@colorfullife.com> |
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* Enforced range limit on SEM_UNDO |
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* (c) 2001 Red Hat Inc |
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* Lockless wakeup * (c) 2003 Manfred Spraul <manfred@colorfullife.com> |
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* Further wakeup optimizations, documentation * (c) 2010 Manfred Spraul <manfred@colorfullife.com> |
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* * support for audit of ipc object properties and permission changes * Dustin Kirkland <dustin.kirkland@us.ibm.com> |
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* * namespaces support * OpenVZ, SWsoft Inc. * Pavel Emelianov <xemul@openvz.org> |
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* * Implementation notes: (May 2010) * This file implements System V semaphores. * * User space visible behavior: * - FIFO ordering for semop() operations (just FIFO, not starvation * protection) * - multiple semaphore operations that alter the same semaphore in * one semop() are handled. * - sem_ctime (time of last semctl()) is updated in the IPC_SET, SETVAL and * SETALL calls. * - two Linux specific semctl() commands: SEM_STAT, SEM_INFO. * - undo adjustments at process exit are limited to 0..SEMVMX. * - namespace are supported. * - SEMMSL, SEMMNS, SEMOPM and SEMMNI can be configured at runtine by writing * to /proc/sys/kernel/sem. * - statistics about the usage are reported in /proc/sysvipc/sem. * * Internals: * - scalability: * - all global variables are read-mostly. * - semop() calls and semctl(RMID) are synchronized by RCU. * - most operations do write operations (actually: spin_lock calls) to * the per-semaphore array structure. * Thus: Perfect SMP scaling between independent semaphore arrays. * If multiple semaphores in one array are used, then cache line * trashing on the semaphore array spinlock will limit the scaling. |
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* - semncnt and semzcnt are calculated on demand in count_semcnt() |
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* - the task that performs a successful semop() scans the list of all * sleeping tasks and completes any pending operations that can be fulfilled. * Semaphores are actively given to waiting tasks (necessary for FIFO). * (see update_queue()) * - To improve the scalability, the actual wake-up calls are performed after * dropping all locks. (see wake_up_sem_queue_prepare(), * wake_up_sem_queue_do()) * - All work is done by the waker, the woken up task does not have to do * anything - not even acquiring a lock or dropping a refcount. * - A woken up task may not even touch the semaphore array anymore, it may * have been destroyed already by a semctl(RMID). * - The synchronizations between wake-ups due to a timeout/signal and a * wake-up due to a completed semaphore operation is achieved by using an * intermediate state (IN_WAKEUP). * - UNDO values are stored in an array (one per process and per * semaphore array, lazily allocated). For backwards compatibility, multiple * modes for the UNDO variables are supported (per process, per thread) * (see copy_semundo, CLONE_SYSVSEM) * - There are two lists of the pending operations: a per-array list * and per-semaphore list (stored in the array). This allows to achieve FIFO * ordering without always scanning all pending operations. * The worst-case behavior is nevertheless O(N^2) for N wakeups. |
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*/ |
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#include <linux/slab.h> #include <linux/spinlock.h> #include <linux/init.h> #include <linux/proc_fs.h> #include <linux/time.h> |
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#include <linux/security.h> #include <linux/syscalls.h> #include <linux/audit.h> |
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#include <linux/capability.h> |
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#include <linux/seq_file.h> |
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#include <linux/rwsem.h> |
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#include <linux/nsproxy.h> |
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#include <linux/ipc_namespace.h> |
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#include <linux/uaccess.h> |
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#include "util.h" |
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/* One semaphore structure for each semaphore in the system. */ struct sem { int semval; /* current value */ |
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/* * PID of the process that last modified the semaphore. For * Linux, specifically these are: * - semop * - semctl, via SETVAL and SETALL. * - at task exit when performing undo adjustments (see exit_sem). */ int sempid; |
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spinlock_t lock; /* spinlock for fine-grained semtimedop */ |
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struct list_head pending_alter; /* pending single-sop operations */ /* that alter the semaphore */ struct list_head pending_const; /* pending single-sop operations */ /* that do not alter the semaphore*/ |
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time_t sem_otime; /* candidate for sem_otime */ |
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} ____cacheline_aligned_in_smp; |
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/* One queue for each sleeping process in the system. */ struct sem_queue { |
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struct list_head list; /* queue of pending operations */ struct task_struct *sleeper; /* this process */ struct sem_undo *undo; /* undo structure */ int pid; /* process id of requesting process */ int status; /* completion status of operation */ struct sembuf *sops; /* array of pending operations */ |
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struct sembuf *blocking; /* the operation that blocked */ |
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int nsops; /* number of operations */ int alter; /* does *sops alter the array? */ }; /* Each task has a list of undo requests. They are executed automatically * when the process exits. */ struct sem_undo { struct list_head list_proc; /* per-process list: * * all undos from one process * rcu protected */ struct rcu_head rcu; /* rcu struct for sem_undo */ struct sem_undo_list *ulp; /* back ptr to sem_undo_list */ struct list_head list_id; /* per semaphore array list: * all undos for one array */ int semid; /* semaphore set identifier */ short *semadj; /* array of adjustments */ /* one per semaphore */ }; /* sem_undo_list controls shared access to the list of sem_undo structures * that may be shared among all a CLONE_SYSVSEM task group. */ struct sem_undo_list { atomic_t refcnt; spinlock_t lock; struct list_head list_proc; }; |
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#define sem_ids(ns) ((ns)->ids[IPC_SEM_IDS]) |
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|
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#define sem_checkid(sma, semid) ipc_checkid(&sma->sem_perm, semid) |
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static int newary(struct ipc_namespace *, struct ipc_params *); |
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static void freeary(struct ipc_namespace *, struct kern_ipc_perm *); |
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#ifdef CONFIG_PROC_FS |
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static int sysvipc_sem_proc_show(struct seq_file *s, void *it); |
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#endif #define SEMMSL_FAST 256 /* 512 bytes on stack */ #define SEMOPM_FAST 64 /* ~ 372 bytes on stack */ /* |
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* Locking: |
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* a) global sem_lock() for read/write |
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* sem_undo.id_next, |
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* sem_array.complex_count, |
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* sem_array.complex_mode * sem_array.pending{_alter,_const}, * sem_array.sem_undo |
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* |
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* b) global or semaphore sem_lock() for read/write: |
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* sem_array.sem_base[i].pending_{const,alter}: |
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* sem_array.complex_mode (for read) * * c) special: * sem_undo_list.list_proc: * * undo_list->lock for write * * rcu for read |
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*/ |
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#define sc_semmsl sem_ctls[0] #define sc_semmns sem_ctls[1] #define sc_semopm sem_ctls[2] #define sc_semmni sem_ctls[3] |
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void sem_init_ns(struct ipc_namespace *ns) |
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{ |
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ns->sc_semmsl = SEMMSL; ns->sc_semmns = SEMMNS; ns->sc_semopm = SEMOPM; ns->sc_semmni = SEMMNI; ns->used_sems = 0; |
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ipc_init_ids(&ns->ids[IPC_SEM_IDS]); |
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} |
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#ifdef CONFIG_IPC_NS |
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void sem_exit_ns(struct ipc_namespace *ns) { |
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free_ipcs(ns, &sem_ids(ns), freeary); |
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idr_destroy(&ns->ids[IPC_SEM_IDS].ipcs_idr); |
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} |
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#endif |
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void __init sem_init(void) |
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{ |
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sem_init_ns(&init_ipc_ns); |
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ipc_init_proc_interface("sysvipc/sem", " key semid perms nsems uid gid cuid cgid otime ctime ", |
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IPC_SEM_IDS, sysvipc_sem_proc_show); |
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} |
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/** * unmerge_queues - unmerge queues, if possible. * @sma: semaphore array * * The function unmerges the wait queues if complex_count is 0. * It must be called prior to dropping the global semaphore array lock. */ static void unmerge_queues(struct sem_array *sma) { struct sem_queue *q, *tq; /* complex operations still around? */ if (sma->complex_count) return; /* * We will switch back to simple mode. * Move all pending operation back into the per-semaphore * queues. */ list_for_each_entry_safe(q, tq, &sma->pending_alter, list) { struct sem *curr; curr = &sma->sem_base[q->sops[0].sem_num]; list_add_tail(&q->list, &curr->pending_alter); } INIT_LIST_HEAD(&sma->pending_alter); } /** |
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* merge_queues - merge single semop queues into global queue |
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* @sma: semaphore array * * This function merges all per-semaphore queues into the global queue. * It is necessary to achieve FIFO ordering for the pending single-sop * operations when a multi-semop operation must sleep. * Only the alter operations must be moved, the const operations can stay. */ static void merge_queues(struct sem_array *sma) { int i; for (i = 0; i < sma->sem_nsems; i++) { struct sem *sem = sma->sem_base + i; list_splice_init(&sem->pending_alter, &sma->pending_alter); } } |
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static void sem_rcu_free(struct rcu_head *head) { struct ipc_rcu *p = container_of(head, struct ipc_rcu, rcu); struct sem_array *sma = ipc_rcu_to_struct(p); security_sem_free(sma); ipc_rcu_free(head); } |
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/* |
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* Enter the mode suitable for non-simple operations: |
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* Caller must own sem_perm.lock. |
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*/ |
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static void complexmode_enter(struct sem_array *sma) |
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{ int i; struct sem *sem; |
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if (sma->complex_mode) { /* We are already in complex_mode. Nothing to do */ |
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return; } |
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/* We need a full barrier after seting complex_mode: * The write to complex_mode must be visible * before we read the first sem->lock spinlock state. */ smp_store_mb(sma->complex_mode, true); |
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for (i = 0; i < sma->sem_nsems; i++) { sem = sma->sem_base + i; spin_unlock_wait(&sem->lock); } |
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/* * spin_unlock_wait() is not a memory barriers, it is only a * control barrier. The code must pair with spin_unlock(&sem->lock), * thus just the control barrier is insufficient. * * smp_rmb() is sufficient, as writes cannot pass the control barrier. */ smp_rmb(); } /* * Try to leave the mode that disallows simple operations: * Caller must own sem_perm.lock. */ static void complexmode_tryleave(struct sem_array *sma) { if (sma->complex_count) { /* Complex ops are sleeping. * We must stay in complex mode */ return; } /* * Immediately after setting complex_mode to false, * a simple op can start. Thus: all memory writes * performed by the current operation must be visible * before we set complex_mode to false. */ smp_store_release(&sma->complex_mode, false); |
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} |
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#define SEM_GLOBAL_LOCK (-1) |
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/* |
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* If the request contains only one semaphore operation, and there are * no complex transactions pending, lock only the semaphore involved. * Otherwise, lock the entire semaphore array, since we either have * multiple semaphores in our own semops, or we need to look at * semaphores from other pending complex operations. |
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*/ static inline int sem_lock(struct sem_array *sma, struct sembuf *sops, int nsops) { |
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struct sem *sem; |
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|
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if (nsops != 1) { /* Complex operation - acquire a full lock */ ipc_lock_object(&sma->sem_perm); |
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|
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/* Prevent parallel simple ops */ complexmode_enter(sma); return SEM_GLOBAL_LOCK; |
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} /* * Only one semaphore affected - try to optimize locking. |
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* Optimized locking is possible if no complex operation * is either enqueued or processed right now. * * Both facts are tracked by complex_mode. |
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*/ sem = sma->sem_base + sops->sem_num; |
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|
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/* * Initial check for complex_mode. Just an optimization, * no locking, no memory barrier. */ if (!sma->complex_mode) { |
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/* |
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* It appears that no complex operation is around. * Acquire the per-semaphore lock. |
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*/ |
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spin_lock(&sem->lock); |
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/* * See 51d7d5205d33 * ("powerpc: Add smp_mb() to arch_spin_is_locked()"): * A full barrier is required: the write of sem->lock * must be visible before the read is executed */ smp_mb(); |
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|
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if (!smp_load_acquire(&sma->complex_mode)) { /* fast path successful! */ return sops->sem_num; |
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} |
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spin_unlock(&sem->lock); } /* slow path: acquire the full lock */ ipc_lock_object(&sma->sem_perm); |
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|
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if (sma->complex_count == 0) { /* False alarm: * There is no complex operation, thus we can switch * back to the fast path. */ spin_lock(&sem->lock); ipc_unlock_object(&sma->sem_perm); return sops->sem_num; |
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} else { |
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/* Not a false alarm, thus complete the sequence for a * full lock. |
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*/ |
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complexmode_enter(sma); return SEM_GLOBAL_LOCK; |
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} |
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} static inline void sem_unlock(struct sem_array *sma, int locknum) { |
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if (locknum == SEM_GLOBAL_LOCK) { |
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unmerge_queues(sma); |
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complexmode_tryleave(sma); |
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ipc_unlock_object(&sma->sem_perm); |
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} else { struct sem *sem = sma->sem_base + locknum; spin_unlock(&sem->lock); } |
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} /* |
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* sem_lock_(check_) routines are called in the paths where the rwsem |
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* is not held. |
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* * The caller holds the RCU read lock. |
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*/ |
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static inline struct sem_array *sem_obtain_lock(struct ipc_namespace *ns, int id, struct sembuf *sops, int nsops, int *locknum) |
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{ |
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struct kern_ipc_perm *ipcp; struct sem_array *sma; |
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|
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ipcp = ipc_obtain_object_idr(&sem_ids(ns), id); |
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if (IS_ERR(ipcp)) return ERR_CAST(ipcp); |
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|
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sma = container_of(ipcp, struct sem_array, sem_perm); *locknum = sem_lock(sma, sops, nsops); |
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/* ipc_rmid() may have already freed the ID while sem_lock * was spinning: verify that the structure is still valid */ |
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if (ipc_valid_object(ipcp)) |
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return container_of(ipcp, struct sem_array, sem_perm); |
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sem_unlock(sma, *locknum); |
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return ERR_PTR(-EINVAL); |
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} |
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static inline struct sem_array *sem_obtain_object(struct ipc_namespace *ns, int id) { |
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struct kern_ipc_perm *ipcp = ipc_obtain_object_idr(&sem_ids(ns), id); |
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if (IS_ERR(ipcp)) return ERR_CAST(ipcp); return container_of(ipcp, struct sem_array, sem_perm); } |
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static inline struct sem_array *sem_obtain_object_check(struct ipc_namespace *ns, int id) { struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&sem_ids(ns), id); if (IS_ERR(ipcp)) return ERR_CAST(ipcp); |
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return container_of(ipcp, struct sem_array, sem_perm); |
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} |
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static inline void sem_lock_and_putref(struct sem_array *sma) { |
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sem_lock(sma, NULL, -1); |
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ipc_rcu_putref(sma, sem_rcu_free); |
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} |
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450 451 452 453 |
static inline void sem_rmid(struct ipc_namespace *ns, struct sem_array *s) { ipc_rmid(&sem_ids(ns), &s->sem_perm); } |
1da177e4c Linux-2.6.12-rc2 |
454 455 456 457 458 |
/* * Lockless wakeup algorithm: * Without the check/retry algorithm a lockless wakeup is possible: * - queue.status is initialized to -EINTR before blocking. * - wakeup is performed by |
1a82e9e1d ipc/sem: separate... |
459 |
* * unlinking the queue entry from the pending list |
1da177e4c Linux-2.6.12-rc2 |
460 461 462 463 464 465 |
* * setting queue.status to IN_WAKEUP * This is the notification for the blocked thread that a * result value is imminent. * * call wake_up_process * * set queue.status to the final value. * - the previously blocked thread checks queue.status: |
239521f31 ipc: whitespace c... |
466 467 468 469 470 |
* * if it's IN_WAKEUP, then it must wait until the value changes * * if it's not -EINTR, then the operation was completed by * update_queue. semtimedop can return queue.status without * performing any operation on the sem array. * * otherwise it must acquire the spinlock and check what's up. |
1da177e4c Linux-2.6.12-rc2 |
471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 |
* * The two-stage algorithm is necessary to protect against the following * races: * - if queue.status is set after wake_up_process, then the woken up idle * thread could race forward and try (and fail) to acquire sma->lock * before update_queue had a chance to set queue.status * - if queue.status is written before wake_up_process and if the * blocked process is woken up by a signal between writing * queue.status and the wake_up_process, then the woken up * process could return from semtimedop and die by calling * sys_exit before wake_up_process is called. Then wake_up_process * will oops, because the task structure is already invalid. * (yes, this happened on s390 with sysv msg). * */ #define IN_WAKEUP 1 |
f4566f048 ipc: fix wrong co... |
487 488 489 490 491 |
/** * newary - Create a new semaphore set * @ns: namespace * @params: ptr to the structure that contains key, semflg and nsems * |
d9a605e40 ipc: rename ids->... |
492 |
* Called with sem_ids.rwsem held (as a writer) |
f4566f048 ipc: fix wrong co... |
493 |
*/ |
7748dbfaa ipc: unify the sy... |
494 |
static int newary(struct ipc_namespace *ns, struct ipc_params *params) |
1da177e4c Linux-2.6.12-rc2 |
495 496 497 498 499 |
{ int id; int retval; struct sem_array *sma; int size; |
7748dbfaa ipc: unify the sy... |
500 501 502 |
key_t key = params->key; int nsems = params->u.nsems; int semflg = params->flg; |
b97e820ff ipc/sem.c: add a ... |
503 |
int i; |
1da177e4c Linux-2.6.12-rc2 |
504 505 506 |
if (!nsems) return -EINVAL; |
e38935341 [PATCH] IPC names... |
507 |
if (ns->used_sems + nsems > ns->sc_semmns) |
1da177e4c Linux-2.6.12-rc2 |
508 |
return -ENOSPC; |
239521f31 ipc: whitespace c... |
509 |
size = sizeof(*sma) + nsems * sizeof(struct sem); |
1da177e4c Linux-2.6.12-rc2 |
510 |
sma = ipc_rcu_alloc(size); |
3ab08fe20 ipc: remove brace... |
511 |
if (!sma) |
1da177e4c Linux-2.6.12-rc2 |
512 |
return -ENOMEM; |
3ab08fe20 ipc: remove brace... |
513 |
|
239521f31 ipc: whitespace c... |
514 |
memset(sma, 0, size); |
1da177e4c Linux-2.6.12-rc2 |
515 516 517 518 519 520 521 |
sma->sem_perm.mode = (semflg & S_IRWXUGO); sma->sem_perm.key = key; sma->sem_perm.security = NULL; retval = security_sem_alloc(sma); if (retval) { |
53dad6d3a ipc: fix race wit... |
522 |
ipc_rcu_putref(sma, ipc_rcu_free); |
1da177e4c Linux-2.6.12-rc2 |
523 524 |
return retval; } |
1da177e4c Linux-2.6.12-rc2 |
525 |
sma->sem_base = (struct sem *) &sma[1]; |
b97e820ff ipc/sem.c: add a ... |
526 |
|
6062a8dc0 ipc,sem: fine gra... |
527 |
for (i = 0; i < nsems; i++) { |
1a82e9e1d ipc/sem: separate... |
528 529 |
INIT_LIST_HEAD(&sma->sem_base[i].pending_alter); INIT_LIST_HEAD(&sma->sem_base[i].pending_const); |
6062a8dc0 ipc,sem: fine gra... |
530 531 |
spin_lock_init(&sma->sem_base[i].lock); } |
b97e820ff ipc/sem.c: add a ... |
532 533 |
sma->complex_count = 0; |
5864a2fd3 ipc/sem.c: fix co... |
534 |
sma->complex_mode = true; /* dropped by sem_unlock below */ |
1a82e9e1d ipc/sem: separate... |
535 536 |
INIT_LIST_HEAD(&sma->pending_alter); INIT_LIST_HEAD(&sma->pending_const); |
4daa28f6d ipc/sem.c: conver... |
537 |
INIT_LIST_HEAD(&sma->list_id); |
1da177e4c Linux-2.6.12-rc2 |
538 539 |
sma->sem_nsems = nsems; sma->sem_ctime = get_seconds(); |
e8577d1f0 ipc/sem.c: fully ... |
540 541 542 543 544 545 546 |
id = ipc_addid(&sem_ids(ns), &sma->sem_perm, ns->sc_semmni); if (id < 0) { ipc_rcu_putref(sma, sem_rcu_free); return id; } ns->used_sems += nsems; |
6062a8dc0 ipc,sem: fine gra... |
547 |
sem_unlock(sma, -1); |
6d49dab8a ipc: move rcu_rea... |
548 |
rcu_read_unlock(); |
1da177e4c Linux-2.6.12-rc2 |
549 |
|
7ca7e564e ipc: store ipcs i... |
550 |
return sma->sem_perm.id; |
1da177e4c Linux-2.6.12-rc2 |
551 |
} |
7748dbfaa ipc: unify the sy... |
552 |
|
f4566f048 ipc: fix wrong co... |
553 |
/* |
d9a605e40 ipc: rename ids->... |
554 |
* Called with sem_ids.rwsem and ipcp locked. |
f4566f048 ipc: fix wrong co... |
555 |
*/ |
03f02c765 Storing ipcs into... |
556 |
static inline int sem_security(struct kern_ipc_perm *ipcp, int semflg) |
7748dbfaa ipc: unify the sy... |
557 |
{ |
03f02c765 Storing ipcs into... |
558 559 560 561 |
struct sem_array *sma; sma = container_of(ipcp, struct sem_array, sem_perm); return security_sem_associate(sma, semflg); |
7748dbfaa ipc: unify the sy... |
562 |
} |
f4566f048 ipc: fix wrong co... |
563 |
/* |
d9a605e40 ipc: rename ids->... |
564 |
* Called with sem_ids.rwsem and ipcp locked. |
f4566f048 ipc: fix wrong co... |
565 |
*/ |
03f02c765 Storing ipcs into... |
566 567 |
static inline int sem_more_checks(struct kern_ipc_perm *ipcp, struct ipc_params *params) |
7748dbfaa ipc: unify the sy... |
568 |
{ |
03f02c765 Storing ipcs into... |
569 570 571 572 |
struct sem_array *sma; sma = container_of(ipcp, struct sem_array, sem_perm); if (params->u.nsems > sma->sem_nsems) |
7748dbfaa ipc: unify the sy... |
573 574 575 576 |
return -EINVAL; return 0; } |
d5460c997 [CVE-2009-0029] S... |
577 |
SYSCALL_DEFINE3(semget, key_t, key, int, nsems, int, semflg) |
1da177e4c Linux-2.6.12-rc2 |
578 |
{ |
e38935341 [PATCH] IPC names... |
579 |
struct ipc_namespace *ns; |
eb66ec44f ipc: constify ipc... |
580 581 582 583 584 |
static const struct ipc_ops sem_ops = { .getnew = newary, .associate = sem_security, .more_checks = sem_more_checks, }; |
7748dbfaa ipc: unify the sy... |
585 |
struct ipc_params sem_params; |
e38935341 [PATCH] IPC names... |
586 587 |
ns = current->nsproxy->ipc_ns; |
1da177e4c Linux-2.6.12-rc2 |
588 |
|
e38935341 [PATCH] IPC names... |
589 |
if (nsems < 0 || nsems > ns->sc_semmsl) |
1da177e4c Linux-2.6.12-rc2 |
590 |
return -EINVAL; |
7ca7e564e ipc: store ipcs i... |
591 |
|
7748dbfaa ipc: unify the sy... |
592 593 594 |
sem_params.key = key; sem_params.flg = semflg; sem_params.u.nsems = nsems; |
1da177e4c Linux-2.6.12-rc2 |
595 |
|
7748dbfaa ipc: unify the sy... |
596 |
return ipcget(ns, &sem_ids(ns), &sem_ops, &sem_params); |
1da177e4c Linux-2.6.12-rc2 |
597 |
} |
78f5009cc ipc/sem.c: avoid ... |
598 599 |
/** * perform_atomic_semop - Perform (if possible) a semaphore operation |
758a6ba39 ipc/sem.c: rename... |
600 |
* @sma: semaphore array |
d198cd6d6 ipc/sem.c: change... |
601 |
* @q: struct sem_queue that describes the operation |
758a6ba39 ipc/sem.c: rename... |
602 603 604 605 |
* * Returns 0 if the operation was possible. * Returns 1 if the operation is impossible, the caller must sleep. * Negative values are error codes. |
1da177e4c Linux-2.6.12-rc2 |
606 |
*/ |
d198cd6d6 ipc/sem.c: change... |
607 |
static int perform_atomic_semop(struct sem_array *sma, struct sem_queue *q) |
1da177e4c Linux-2.6.12-rc2 |
608 |
{ |
d198cd6d6 ipc/sem.c: change... |
609 |
int result, sem_op, nsops, pid; |
1da177e4c Linux-2.6.12-rc2 |
610 |
struct sembuf *sop; |
239521f31 ipc: whitespace c... |
611 |
struct sem *curr; |
d198cd6d6 ipc/sem.c: change... |
612 613 614 615 616 617 |
struct sembuf *sops; struct sem_undo *un; sops = q->sops; nsops = q->nsops; un = q->undo; |
1da177e4c Linux-2.6.12-rc2 |
618 619 620 621 622 |
for (sop = sops; sop < sops + nsops; sop++) { curr = sma->sem_base + sop->sem_num; sem_op = sop->sem_op; result = curr->semval; |
78f5009cc ipc/sem.c: avoid ... |
623 |
|
1da177e4c Linux-2.6.12-rc2 |
624 625 626 627 628 629 630 631 |
if (!sem_op && result) goto would_block; result += sem_op; if (result < 0) goto would_block; if (result > SEMVMX) goto out_of_range; |
78f5009cc ipc/sem.c: avoid ... |
632 |
|
1da177e4c Linux-2.6.12-rc2 |
633 634 |
if (sop->sem_flg & SEM_UNDO) { int undo = un->semadj[sop->sem_num] - sem_op; |
78f5009cc ipc/sem.c: avoid ... |
635 |
/* Exceeding the undo range is an error. */ |
1da177e4c Linux-2.6.12-rc2 |
636 637 |
if (undo < (-SEMAEM - 1) || undo > SEMAEM) goto out_of_range; |
78f5009cc ipc/sem.c: avoid ... |
638 |
un->semadj[sop->sem_num] = undo; |
1da177e4c Linux-2.6.12-rc2 |
639 |
} |
78f5009cc ipc/sem.c: avoid ... |
640 |
|
1da177e4c Linux-2.6.12-rc2 |
641 642 643 644 |
curr->semval = result; } sop--; |
d198cd6d6 ipc/sem.c: change... |
645 |
pid = q->pid; |
1da177e4c Linux-2.6.12-rc2 |
646 647 |
while (sop >= sops) { sma->sem_base[sop->sem_num].sempid = pid; |
1da177e4c Linux-2.6.12-rc2 |
648 649 |
sop--; } |
78f5009cc ipc/sem.c: avoid ... |
650 |
|
1da177e4c Linux-2.6.12-rc2 |
651 652 653 654 655 656 657 |
return 0; out_of_range: result = -ERANGE; goto undo; would_block: |
ed247b7ca ipc/sem.c: store ... |
658 |
q->blocking = sop; |
1da177e4c Linux-2.6.12-rc2 |
659 660 661 662 663 664 665 666 |
if (sop->sem_flg & IPC_NOWAIT) result = -EAGAIN; else result = 1; undo: sop--; while (sop >= sops) { |
78f5009cc ipc/sem.c: avoid ... |
667 668 669 670 |
sem_op = sop->sem_op; sma->sem_base[sop->sem_num].semval -= sem_op; if (sop->sem_flg & SEM_UNDO) un->semadj[sop->sem_num] += sem_op; |
1da177e4c Linux-2.6.12-rc2 |
671 672 673 674 675 |
sop--; } return result; } |
0a2b9d4c7 ipc/sem.c: move w... |
676 677 678 679 680 |
/** wake_up_sem_queue_prepare(q, error): Prepare wake-up * @q: queue entry that must be signaled * @error: Error value for the signal * * Prepare the wake-up of the queue entry q. |
d4212093d ipc/sem.c: sem pr... |
681 |
*/ |
0a2b9d4c7 ipc/sem.c: move w... |
682 683 |
static void wake_up_sem_queue_prepare(struct list_head *pt, struct sem_queue *q, int error) |
d4212093d ipc/sem.c: sem pr... |
684 |
{ |
0a2b9d4c7 ipc/sem.c: move w... |
685 686 687 688 689 690 691 |
if (list_empty(pt)) { /* * Hold preempt off so that we don't get preempted and have the * wakee busy-wait until we're scheduled back on. */ preempt_disable(); } |
d4212093d ipc/sem.c: sem pr... |
692 |
q->status = IN_WAKEUP; |
0a2b9d4c7 ipc/sem.c: move w... |
693 |
q->pid = error; |
9f1bc2c90 ipc,sem: have onl... |
694 |
list_add_tail(&q->list, pt); |
0a2b9d4c7 ipc/sem.c: move w... |
695 696 697 |
} /** |
8001c8581 ipc: standardize ... |
698 |
* wake_up_sem_queue_do - do the actual wake-up |
0a2b9d4c7 ipc/sem.c: move w... |
699 700 701 702 703 704 705 706 707 708 709 710 711 |
* @pt: list of tasks to be woken up * * Do the actual wake-up. * The function is called without any locks held, thus the semaphore array * could be destroyed already and the tasks can disappear as soon as the * status is set to the actual return code. */ static void wake_up_sem_queue_do(struct list_head *pt) { struct sem_queue *q, *t; int did_something; did_something = !list_empty(pt); |
9f1bc2c90 ipc,sem: have onl... |
712 |
list_for_each_entry_safe(q, t, pt, list) { |
0a2b9d4c7 ipc/sem.c: move w... |
713 714 715 716 717 718 719 |
wake_up_process(q->sleeper); /* q can disappear immediately after writing q->status. */ smp_wmb(); q->status = q->pid; } if (did_something) preempt_enable(); |
d4212093d ipc/sem.c: sem pr... |
720 |
} |
b97e820ff ipc/sem.c: add a ... |
721 722 723 |
static void unlink_queue(struct sem_array *sma, struct sem_queue *q) { list_del(&q->list); |
9f1bc2c90 ipc,sem: have onl... |
724 |
if (q->nsops > 1) |
b97e820ff ipc/sem.c: add a ... |
725 726 |
sma->complex_count--; } |
fd5db4225 ipc/sem.c: optimi... |
727 728 729 730 731 732 733 |
/** check_restart(sma, q) * @sma: semaphore array * @q: the operation that just completed * * update_queue is O(N^2) when it restarts scanning the whole queue of * waiting operations. Therefore this function checks if the restart is * really necessary. It is called after a previously waiting operation |
1a82e9e1d ipc/sem: separate... |
734 735 |
* modified the array. * Note that wait-for-zero operations are handled without restart. |
fd5db4225 ipc/sem.c: optimi... |
736 737 738 |
*/ static int check_restart(struct sem_array *sma, struct sem_queue *q) { |
1a82e9e1d ipc/sem: separate... |
739 740 |
/* pending complex alter operations are too difficult to analyse */ if (!list_empty(&sma->pending_alter)) |
fd5db4225 ipc/sem.c: optimi... |
741 742 743 744 745 |
return 1; /* we were a sleeping complex operation. Too difficult */ if (q->nsops > 1) return 1; |
1a82e9e1d ipc/sem: separate... |
746 747 748 749 750 751 752 753 754 755 756 757 758 |
/* It is impossible that someone waits for the new value: * - complex operations always restart. * - wait-for-zero are handled seperately. * - q is a previously sleeping simple operation that * altered the array. It must be a decrement, because * simple increments never sleep. * - If there are older (higher priority) decrements * in the queue, then they have observed the original * semval value and couldn't proceed. The operation * decremented to value - thus they won't proceed either. */ return 0; } |
fd5db4225 ipc/sem.c: optimi... |
759 |
|
1a82e9e1d ipc/sem: separate... |
760 |
/** |
8001c8581 ipc: standardize ... |
761 |
* wake_const_ops - wake up non-alter tasks |
1a82e9e1d ipc/sem: separate... |
762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 |
* @sma: semaphore array. * @semnum: semaphore that was modified. * @pt: list head for the tasks that must be woken up. * * wake_const_ops must be called after a semaphore in a semaphore array * was set to 0. If complex const operations are pending, wake_const_ops must * be called with semnum = -1, as well as with the number of each modified * semaphore. * The tasks that must be woken up are added to @pt. The return code * is stored in q->pid. * The function returns 1 if at least one operation was completed successfully. */ static int wake_const_ops(struct sem_array *sma, int semnum, struct list_head *pt) { struct sem_queue *q; struct list_head *walk; struct list_head *pending_list; int semop_completed = 0; if (semnum == -1) pending_list = &sma->pending_const; else pending_list = &sma->sem_base[semnum].pending_const; |
fd5db4225 ipc/sem.c: optimi... |
786 |
|
1a82e9e1d ipc/sem: separate... |
787 788 789 790 791 792 |
walk = pending_list->next; while (walk != pending_list) { int error; q = container_of(walk, struct sem_queue, list); walk = walk->next; |
d198cd6d6 ipc/sem.c: change... |
793 |
error = perform_atomic_semop(sma, q); |
1a82e9e1d ipc/sem: separate... |
794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 |
if (error <= 0) { /* operation completed, remove from queue & wakeup */ unlink_queue(sma, q); wake_up_sem_queue_prepare(pt, q, error); if (error == 0) semop_completed = 1; } } return semop_completed; } /** |
8001c8581 ipc: standardize ... |
809 |
* do_smart_wakeup_zero - wakeup all wait for zero tasks |
1a82e9e1d ipc/sem: separate... |
810 811 812 813 814 |
* @sma: semaphore array * @sops: operations that were performed * @nsops: number of operations * @pt: list head of the tasks that must be woken up. * |
8001c8581 ipc: standardize ... |
815 816 |
* Checks all required queue for wait-for-zero operations, based * on the actual changes that were performed on the semaphore array. |
1a82e9e1d ipc/sem: separate... |
817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 |
* The function returns 1 if at least one operation was completed successfully. */ static int do_smart_wakeup_zero(struct sem_array *sma, struct sembuf *sops, int nsops, struct list_head *pt) { int i; int semop_completed = 0; int got_zero = 0; /* first: the per-semaphore queues, if known */ if (sops) { for (i = 0; i < nsops; i++) { int num = sops[i].sem_num; if (sma->sem_base[num].semval == 0) { got_zero = 1; semop_completed |= wake_const_ops(sma, num, pt); } } } else { /* * No sops means modified semaphores not known. * Assume all were changed. |
fd5db4225 ipc/sem.c: optimi... |
840 |
*/ |
1a82e9e1d ipc/sem: separate... |
841 842 843 844 845 846 |
for (i = 0; i < sma->sem_nsems; i++) { if (sma->sem_base[i].semval == 0) { got_zero = 1; semop_completed |= wake_const_ops(sma, i, pt); } } |
fd5db4225 ipc/sem.c: optimi... |
847 848 |
} /* |
1a82e9e1d ipc/sem: separate... |
849 850 |
* If one of the modified semaphores got 0, * then check the global queue, too. |
fd5db4225 ipc/sem.c: optimi... |
851 |
*/ |
1a82e9e1d ipc/sem: separate... |
852 853 |
if (got_zero) semop_completed |= wake_const_ops(sma, -1, pt); |
fd5db4225 ipc/sem.c: optimi... |
854 |
|
1a82e9e1d ipc/sem: separate... |
855 |
return semop_completed; |
fd5db4225 ipc/sem.c: optimi... |
856 |
} |
636c6be82 ipc/sem.c: optimi... |
857 858 |
/** |
8001c8581 ipc: standardize ... |
859 |
* update_queue - look for tasks that can be completed. |
636c6be82 ipc/sem.c: optimi... |
860 861 |
* @sma: semaphore array. * @semnum: semaphore that was modified. |
0a2b9d4c7 ipc/sem.c: move w... |
862 |
* @pt: list head for the tasks that must be woken up. |
636c6be82 ipc/sem.c: optimi... |
863 864 |
* * update_queue must be called after a semaphore in a semaphore array |
9f1bc2c90 ipc,sem: have onl... |
865 866 867 |
* was modified. If multiple semaphores were modified, update_queue must * be called with semnum = -1, as well as with the number of each modified * semaphore. |
0a2b9d4c7 ipc/sem.c: move w... |
868 869 |
* The tasks that must be woken up are added to @pt. The return code * is stored in q->pid. |
1a82e9e1d ipc/sem: separate... |
870 871 |
* The function internally checks if const operations can now succeed. * |
0a2b9d4c7 ipc/sem.c: move w... |
872 |
* The function return 1 if at least one semop was completed successfully. |
1da177e4c Linux-2.6.12-rc2 |
873 |
*/ |
0a2b9d4c7 ipc/sem.c: move w... |
874 |
static int update_queue(struct sem_array *sma, int semnum, struct list_head *pt) |
1da177e4c Linux-2.6.12-rc2 |
875 |
{ |
636c6be82 ipc/sem.c: optimi... |
876 877 878 |
struct sem_queue *q; struct list_head *walk; struct list_head *pending_list; |
0a2b9d4c7 ipc/sem.c: move w... |
879 |
int semop_completed = 0; |
636c6be82 ipc/sem.c: optimi... |
880 |
|
9f1bc2c90 ipc,sem: have onl... |
881 |
if (semnum == -1) |
1a82e9e1d ipc/sem: separate... |
882 |
pending_list = &sma->pending_alter; |
9f1bc2c90 ipc,sem: have onl... |
883 |
else |
1a82e9e1d ipc/sem: separate... |
884 |
pending_list = &sma->sem_base[semnum].pending_alter; |
9cad200c7 ipc/sem.c: sem us... |
885 886 |
again: |
636c6be82 ipc/sem.c: optimi... |
887 888 |
walk = pending_list->next; while (walk != pending_list) { |
fd5db4225 ipc/sem.c: optimi... |
889 |
int error, restart; |
636c6be82 ipc/sem.c: optimi... |
890 |
|
9f1bc2c90 ipc,sem: have onl... |
891 |
q = container_of(walk, struct sem_queue, list); |
636c6be82 ipc/sem.c: optimi... |
892 |
walk = walk->next; |
1da177e4c Linux-2.6.12-rc2 |
893 |
|
d987f8b21 ipc/sem.c: optimi... |
894 895 |
/* If we are scanning the single sop, per-semaphore list of * one semaphore and that semaphore is 0, then it is not |
1a82e9e1d ipc/sem: separate... |
896 |
* necessary to scan further: simple increments |
d987f8b21 ipc/sem.c: optimi... |
897 898 899 900 |
* that affect only one entry succeed immediately and cannot * be in the per semaphore pending queue, and decrements * cannot be successful if the value is already 0. */ |
1a82e9e1d ipc/sem: separate... |
901 |
if (semnum != -1 && sma->sem_base[semnum].semval == 0) |
d987f8b21 ipc/sem.c: optimi... |
902 |
break; |
d198cd6d6 ipc/sem.c: change... |
903 |
error = perform_atomic_semop(sma, q); |
1da177e4c Linux-2.6.12-rc2 |
904 905 |
/* Does q->sleeper still need to sleep? */ |
9cad200c7 ipc/sem.c: sem us... |
906 907 |
if (error > 0) continue; |
b97e820ff ipc/sem.c: add a ... |
908 |
unlink_queue(sma, q); |
9cad200c7 ipc/sem.c: sem us... |
909 |
|
0a2b9d4c7 ipc/sem.c: move w... |
910 |
if (error) { |
fd5db4225 ipc/sem.c: optimi... |
911 |
restart = 0; |
0a2b9d4c7 ipc/sem.c: move w... |
912 913 |
} else { semop_completed = 1; |
1a82e9e1d ipc/sem: separate... |
914 |
do_smart_wakeup_zero(sma, q->sops, q->nsops, pt); |
fd5db4225 ipc/sem.c: optimi... |
915 |
restart = check_restart(sma, q); |
0a2b9d4c7 ipc/sem.c: move w... |
916 |
} |
fd5db4225 ipc/sem.c: optimi... |
917 |
|
0a2b9d4c7 ipc/sem.c: move w... |
918 |
wake_up_sem_queue_prepare(pt, q, error); |
fd5db4225 ipc/sem.c: optimi... |
919 |
if (restart) |
9cad200c7 ipc/sem.c: sem us... |
920 |
goto again; |
1da177e4c Linux-2.6.12-rc2 |
921 |
} |
0a2b9d4c7 ipc/sem.c: move w... |
922 |
return semop_completed; |
1da177e4c Linux-2.6.12-rc2 |
923 |
} |
0a2b9d4c7 ipc/sem.c: move w... |
924 |
/** |
8001c8581 ipc: standardize ... |
925 |
* set_semotime - set sem_otime |
0e8c66569 ipc/sem.c: update... |
926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 |
* @sma: semaphore array * @sops: operations that modified the array, may be NULL * * sem_otime is replicated to avoid cache line trashing. * This function sets one instance to the current time. */ static void set_semotime(struct sem_array *sma, struct sembuf *sops) { if (sops == NULL) { sma->sem_base[0].sem_otime = get_seconds(); } else { sma->sem_base[sops[0].sem_num].sem_otime = get_seconds(); } } /** |
8001c8581 ipc: standardize ... |
943 |
* do_smart_update - optimized update_queue |
fd5db4225 ipc/sem.c: optimi... |
944 945 946 |
* @sma: semaphore array * @sops: operations that were performed * @nsops: number of operations |
0a2b9d4c7 ipc/sem.c: move w... |
947 948 |
* @otime: force setting otime * @pt: list head of the tasks that must be woken up. |
fd5db4225 ipc/sem.c: optimi... |
949 |
* |
1a82e9e1d ipc/sem: separate... |
950 951 |
* do_smart_update() does the required calls to update_queue and wakeup_zero, * based on the actual changes that were performed on the semaphore array. |
0a2b9d4c7 ipc/sem.c: move w... |
952 953 954 |
* Note that the function does not do the actual wake-up: the caller is * responsible for calling wake_up_sem_queue_do(@pt). * It is safe to perform this call after dropping all locks. |
fd5db4225 ipc/sem.c: optimi... |
955 |
*/ |
0a2b9d4c7 ipc/sem.c: move w... |
956 957 |
static void do_smart_update(struct sem_array *sma, struct sembuf *sops, int nsops, int otime, struct list_head *pt) |
fd5db4225 ipc/sem.c: optimi... |
958 959 |
{ int i; |
1a82e9e1d ipc/sem: separate... |
960 |
otime |= do_smart_wakeup_zero(sma, sops, nsops, pt); |
f269f40ad ipc/sem.c: always... |
961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 |
if (!list_empty(&sma->pending_alter)) { /* semaphore array uses the global queue - just process it. */ otime |= update_queue(sma, -1, pt); } else { if (!sops) { /* * No sops, thus the modified semaphores are not * known. Check all. */ for (i = 0; i < sma->sem_nsems; i++) otime |= update_queue(sma, i, pt); } else { /* * Check the semaphores that were increased: * - No complex ops, thus all sleeping ops are * decrease. * - if we decreased the value, then any sleeping * semaphore ops wont be able to run: If the * previous value was too small, then the new * value will be too small, too. */ for (i = 0; i < nsops; i++) { if (sops[i].sem_op > 0) { otime |= update_queue(sma, sops[i].sem_num, pt); } |
ab465df9d ipc/sem.c: Fix mi... |
987 |
} |
9f1bc2c90 ipc,sem: have onl... |
988 |
} |
fd5db4225 ipc/sem.c: optimi... |
989 |
} |
0e8c66569 ipc/sem.c: update... |
990 991 |
if (otime) set_semotime(sma, sops); |
fd5db4225 ipc/sem.c: optimi... |
992 |
} |
2f2ed41dc ipc/sem.c: remove... |
993 |
/* |
b220c57ae ipc/sem.c: make s... |
994 |
* check_qop: Test if a queued operation sleeps on the semaphore semnum |
2f2ed41dc ipc/sem.c: remove... |
995 996 997 998 |
*/ static int check_qop(struct sem_array *sma, int semnum, struct sem_queue *q, bool count_zero) { |
b220c57ae ipc/sem.c: make s... |
999 |
struct sembuf *sop = q->blocking; |
2f2ed41dc ipc/sem.c: remove... |
1000 |
|
9b44ee2ee ipc/sem.c: add a ... |
1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 |
/* * Linux always (since 0.99.10) reported a task as sleeping on all * semaphores. This violates SUS, therefore it was changed to the * standard compliant behavior. * Give the administrators a chance to notice that an application * might misbehave because it relies on the Linux behavior. */ pr_info_once("semctl(GETNCNT/GETZCNT) is since 3.16 Single Unix Specification compliant. " "The task %s (%d) triggered the difference, watch for misbehavior. ", current->comm, task_pid_nr(current)); |
b220c57ae ipc/sem.c: make s... |
1013 1014 |
if (sop->sem_num != semnum) return 0; |
2f2ed41dc ipc/sem.c: remove... |
1015 |
|
b220c57ae ipc/sem.c: make s... |
1016 1017 1018 1019 1020 1021 |
if (count_zero && sop->sem_op == 0) return 1; if (!count_zero && sop->sem_op < 0) return 1; return 0; |
2f2ed41dc ipc/sem.c: remove... |
1022 |
} |
1da177e4c Linux-2.6.12-rc2 |
1023 1024 1025 |
/* The following counts are associated to each semaphore: * semncnt number of tasks waiting on semval being nonzero * semzcnt number of tasks waiting on semval being zero |
b220c57ae ipc/sem.c: make s... |
1026 1027 1028 |
* * Per definition, a task waits only on the semaphore of the first semop * that cannot proceed, even if additional operation would block, too. |
1da177e4c Linux-2.6.12-rc2 |
1029 |
*/ |
2f2ed41dc ipc/sem.c: remove... |
1030 1031 |
static int count_semcnt(struct sem_array *sma, ushort semnum, bool count_zero) |
1da177e4c Linux-2.6.12-rc2 |
1032 |
{ |
2f2ed41dc ipc/sem.c: remove... |
1033 |
struct list_head *l; |
239521f31 ipc: whitespace c... |
1034 |
struct sem_queue *q; |
2f2ed41dc ipc/sem.c: remove... |
1035 |
int semcnt; |
1da177e4c Linux-2.6.12-rc2 |
1036 |
|
2f2ed41dc ipc/sem.c: remove... |
1037 1038 1039 1040 1041 1042 |
semcnt = 0; /* First: check the simple operations. They are easy to evaluate */ if (count_zero) l = &sma->sem_base[semnum].pending_const; else l = &sma->sem_base[semnum].pending_alter; |
1da177e4c Linux-2.6.12-rc2 |
1043 |
|
2f2ed41dc ipc/sem.c: remove... |
1044 1045 1046 1047 1048 |
list_for_each_entry(q, l, list) { /* all task on a per-semaphore list sleep on exactly * that semaphore */ semcnt++; |
ebc2e5e6a ipc,sem: fix semc... |
1049 |
} |
2f2ed41dc ipc/sem.c: remove... |
1050 |
/* Then: check the complex operations. */ |
1994862dc ipc/sem.c: bugfix... |
1051 |
list_for_each_entry(q, &sma->pending_alter, list) { |
2f2ed41dc ipc/sem.c: remove... |
1052 1053 1054 1055 1056 1057 |
semcnt += check_qop(sma, semnum, q, count_zero); } if (count_zero) { list_for_each_entry(q, &sma->pending_const, list) { semcnt += check_qop(sma, semnum, q, count_zero); } |
1994862dc ipc/sem.c: bugfix... |
1058 |
} |
2f2ed41dc ipc/sem.c: remove... |
1059 |
return semcnt; |
1da177e4c Linux-2.6.12-rc2 |
1060 |
} |
d9a605e40 ipc: rename ids->... |
1061 1062 |
/* Free a semaphore set. freeary() is called with sem_ids.rwsem locked * as a writer and the spinlock for this semaphore set hold. sem_ids.rwsem |
3e148c799 fix idr_find() lo... |
1063 |
* remains locked on exit. |
1da177e4c Linux-2.6.12-rc2 |
1064 |
*/ |
01b8b07a5 IPC: consolidate ... |
1065 |
static void freeary(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp) |
1da177e4c Linux-2.6.12-rc2 |
1066 |
{ |
380af1b33 ipc/sem.c: rewrit... |
1067 1068 |
struct sem_undo *un, *tu; struct sem_queue *q, *tq; |
01b8b07a5 IPC: consolidate ... |
1069 |
struct sem_array *sma = container_of(ipcp, struct sem_array, sem_perm); |
0a2b9d4c7 ipc/sem.c: move w... |
1070 |
struct list_head tasks; |
9f1bc2c90 ipc,sem: have onl... |
1071 |
int i; |
1da177e4c Linux-2.6.12-rc2 |
1072 |
|
380af1b33 ipc/sem.c: rewrit... |
1073 |
/* Free the existing undo structures for this semaphore set. */ |
cf9d5d78d ipc: close open c... |
1074 |
ipc_assert_locked_object(&sma->sem_perm); |
380af1b33 ipc/sem.c: rewrit... |
1075 1076 1077 |
list_for_each_entry_safe(un, tu, &sma->list_id, list_id) { list_del(&un->list_id); spin_lock(&un->ulp->lock); |
1da177e4c Linux-2.6.12-rc2 |
1078 |
un->semid = -1; |
380af1b33 ipc/sem.c: rewrit... |
1079 1080 |
list_del_rcu(&un->list_proc); spin_unlock(&un->ulp->lock); |
693a8b6ee ipc,rcu: Convert ... |
1081 |
kfree_rcu(un, rcu); |
380af1b33 ipc/sem.c: rewrit... |
1082 |
} |
1da177e4c Linux-2.6.12-rc2 |
1083 1084 |
/* Wake up all pending processes and let them fail with EIDRM. */ |
0a2b9d4c7 ipc/sem.c: move w... |
1085 |
INIT_LIST_HEAD(&tasks); |
1a82e9e1d ipc/sem: separate... |
1086 1087 1088 1089 1090 1091 |
list_for_each_entry_safe(q, tq, &sma->pending_const, list) { unlink_queue(sma, q); wake_up_sem_queue_prepare(&tasks, q, -EIDRM); } list_for_each_entry_safe(q, tq, &sma->pending_alter, list) { |
b97e820ff ipc/sem.c: add a ... |
1092 |
unlink_queue(sma, q); |
0a2b9d4c7 ipc/sem.c: move w... |
1093 |
wake_up_sem_queue_prepare(&tasks, q, -EIDRM); |
1da177e4c Linux-2.6.12-rc2 |
1094 |
} |
9f1bc2c90 ipc,sem: have onl... |
1095 1096 |
for (i = 0; i < sma->sem_nsems; i++) { struct sem *sem = sma->sem_base + i; |
1a82e9e1d ipc/sem: separate... |
1097 1098 1099 1100 1101 |
list_for_each_entry_safe(q, tq, &sem->pending_const, list) { unlink_queue(sma, q); wake_up_sem_queue_prepare(&tasks, q, -EIDRM); } list_for_each_entry_safe(q, tq, &sem->pending_alter, list) { |
9f1bc2c90 ipc,sem: have onl... |
1102 1103 1104 1105 |
unlink_queue(sma, q); wake_up_sem_queue_prepare(&tasks, q, -EIDRM); } } |
1da177e4c Linux-2.6.12-rc2 |
1106 |
|
7ca7e564e ipc: store ipcs i... |
1107 1108 |
/* Remove the semaphore set from the IDR */ sem_rmid(ns, sma); |
6062a8dc0 ipc,sem: fine gra... |
1109 |
sem_unlock(sma, -1); |
6d49dab8a ipc: move rcu_rea... |
1110 |
rcu_read_unlock(); |
1da177e4c Linux-2.6.12-rc2 |
1111 |
|
0a2b9d4c7 ipc/sem.c: move w... |
1112 |
wake_up_sem_queue_do(&tasks); |
e38935341 [PATCH] IPC names... |
1113 |
ns->used_sems -= sma->sem_nsems; |
53dad6d3a ipc: fix race wit... |
1114 |
ipc_rcu_putref(sma, sem_rcu_free); |
1da177e4c Linux-2.6.12-rc2 |
1115 1116 1117 1118 |
} static unsigned long copy_semid_to_user(void __user *buf, struct semid64_ds *in, int version) { |
239521f31 ipc: whitespace c... |
1119 |
switch (version) { |
1da177e4c Linux-2.6.12-rc2 |
1120 1121 1122 1123 1124 |
case IPC_64: return copy_to_user(buf, in, sizeof(*in)); case IPC_OLD: { struct semid_ds out; |
982f7c2b2 sys_semctl: fix k... |
1125 |
memset(&out, 0, sizeof(out)); |
1da177e4c Linux-2.6.12-rc2 |
1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 |
ipc64_perm_to_ipc_perm(&in->sem_perm, &out.sem_perm); out.sem_otime = in->sem_otime; out.sem_ctime = in->sem_ctime; out.sem_nsems = in->sem_nsems; return copy_to_user(buf, &out, sizeof(out)); } default: return -EINVAL; } } |
d12e1e50e ipc/sem.c: replac... |
1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 |
static time_t get_semotime(struct sem_array *sma) { int i; time_t res; res = sma->sem_base[0].sem_otime; for (i = 1; i < sma->sem_nsems; i++) { time_t to = sma->sem_base[i].sem_otime; if (to > res) res = to; } return res; } |
4b9fcb0ec IPC/semaphores: c... |
1152 |
static int semctl_nolock(struct ipc_namespace *ns, int semid, |
e1fd1f490 get rid of union ... |
1153 |
int cmd, int version, void __user *p) |
1da177e4c Linux-2.6.12-rc2 |
1154 |
{ |
e5cc9c7b1 ipc: remove unrea... |
1155 |
int err; |
1da177e4c Linux-2.6.12-rc2 |
1156 |
struct sem_array *sma; |
239521f31 ipc: whitespace c... |
1157 |
switch (cmd) { |
1da177e4c Linux-2.6.12-rc2 |
1158 1159 1160 1161 1162 1163 1164 1165 1166 |
case IPC_INFO: case SEM_INFO: { struct seminfo seminfo; int max_id; err = security_sem_semctl(NULL, cmd); if (err) return err; |
46c0a8ca3 ipc, kernel: clea... |
1167 |
|
239521f31 ipc: whitespace c... |
1168 |
memset(&seminfo, 0, sizeof(seminfo)); |
e38935341 [PATCH] IPC names... |
1169 1170 1171 1172 |
seminfo.semmni = ns->sc_semmni; seminfo.semmns = ns->sc_semmns; seminfo.semmsl = ns->sc_semmsl; seminfo.semopm = ns->sc_semopm; |
1da177e4c Linux-2.6.12-rc2 |
1173 1174 1175 1176 |
seminfo.semvmx = SEMVMX; seminfo.semmnu = SEMMNU; seminfo.semmap = SEMMAP; seminfo.semume = SEMUME; |
d9a605e40 ipc: rename ids->... |
1177 |
down_read(&sem_ids(ns).rwsem); |
1da177e4c Linux-2.6.12-rc2 |
1178 |
if (cmd == SEM_INFO) { |
e38935341 [PATCH] IPC names... |
1179 1180 |
seminfo.semusz = sem_ids(ns).in_use; seminfo.semaem = ns->used_sems; |
1da177e4c Linux-2.6.12-rc2 |
1181 1182 1183 1184 |
} else { seminfo.semusz = SEMUSZ; seminfo.semaem = SEMAEM; } |
7ca7e564e ipc: store ipcs i... |
1185 |
max_id = ipc_get_maxid(&sem_ids(ns)); |
d9a605e40 ipc: rename ids->... |
1186 |
up_read(&sem_ids(ns).rwsem); |
46c0a8ca3 ipc, kernel: clea... |
1187 |
if (copy_to_user(p, &seminfo, sizeof(struct seminfo))) |
1da177e4c Linux-2.6.12-rc2 |
1188 |
return -EFAULT; |
239521f31 ipc: whitespace c... |
1189 |
return (max_id < 0) ? 0 : max_id; |
1da177e4c Linux-2.6.12-rc2 |
1190 |
} |
4b9fcb0ec IPC/semaphores: c... |
1191 |
case IPC_STAT: |
1da177e4c Linux-2.6.12-rc2 |
1192 1193 1194 |
case SEM_STAT: { struct semid64_ds tbuf; |
16df3674e ipc,sem: do not h... |
1195 1196 1197 |
int id = 0; memset(&tbuf, 0, sizeof(tbuf)); |
1da177e4c Linux-2.6.12-rc2 |
1198 |
|
941b0304a ipc: simplify rcu... |
1199 |
rcu_read_lock(); |
4b9fcb0ec IPC/semaphores: c... |
1200 |
if (cmd == SEM_STAT) { |
16df3674e ipc,sem: do not h... |
1201 1202 1203 1204 1205 |
sma = sem_obtain_object(ns, semid); if (IS_ERR(sma)) { err = PTR_ERR(sma); goto out_unlock; } |
4b9fcb0ec IPC/semaphores: c... |
1206 1207 |
id = sma->sem_perm.id; } else { |
16df3674e ipc,sem: do not h... |
1208 1209 1210 1211 1212 |
sma = sem_obtain_object_check(ns, semid); if (IS_ERR(sma)) { err = PTR_ERR(sma); goto out_unlock; } |
4b9fcb0ec IPC/semaphores: c... |
1213 |
} |
1da177e4c Linux-2.6.12-rc2 |
1214 1215 |
err = -EACCES; |
b0e77598f userns: user name... |
1216 |
if (ipcperms(ns, &sma->sem_perm, S_IRUGO)) |
1da177e4c Linux-2.6.12-rc2 |
1217 1218 1219 1220 1221 |
goto out_unlock; err = security_sem_semctl(sma, cmd); if (err) goto out_unlock; |
1da177e4c Linux-2.6.12-rc2 |
1222 |
kernel_to_ipc64_perm(&sma->sem_perm, &tbuf.sem_perm); |
d12e1e50e ipc/sem.c: replac... |
1223 1224 1225 |
tbuf.sem_otime = get_semotime(sma); tbuf.sem_ctime = sma->sem_ctime; tbuf.sem_nsems = sma->sem_nsems; |
16df3674e ipc,sem: do not h... |
1226 |
rcu_read_unlock(); |
e1fd1f490 get rid of union ... |
1227 |
if (copy_semid_to_user(p, &tbuf, version)) |
1da177e4c Linux-2.6.12-rc2 |
1228 1229 1230 1231 1232 1233 |
return -EFAULT; return id; } default: return -EINVAL; } |
1da177e4c Linux-2.6.12-rc2 |
1234 |
out_unlock: |
16df3674e ipc,sem: do not h... |
1235 |
rcu_read_unlock(); |
1da177e4c Linux-2.6.12-rc2 |
1236 1237 |
return err; } |
e1fd1f490 get rid of union ... |
1238 1239 1240 1241 1242 |
static int semctl_setval(struct ipc_namespace *ns, int semid, int semnum, unsigned long arg) { struct sem_undo *un; struct sem_array *sma; |
239521f31 ipc: whitespace c... |
1243 |
struct sem *curr; |
e1fd1f490 get rid of union ... |
1244 |
int err; |
e1fd1f490 get rid of union ... |
1245 1246 1247 1248 1249 1250 1251 1252 1253 |
struct list_head tasks; int val; #if defined(CONFIG_64BIT) && defined(__BIG_ENDIAN) /* big-endian 64bit */ val = arg >> 32; #else /* 32bit or little-endian 64bit */ val = arg; #endif |
6062a8dc0 ipc,sem: fine gra... |
1254 1255 |
if (val > SEMVMX || val < 0) return -ERANGE; |
e1fd1f490 get rid of union ... |
1256 1257 |
INIT_LIST_HEAD(&tasks); |
e1fd1f490 get rid of union ... |
1258 |
|
6062a8dc0 ipc,sem: fine gra... |
1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 |
rcu_read_lock(); sma = sem_obtain_object_check(ns, semid); if (IS_ERR(sma)) { rcu_read_unlock(); return PTR_ERR(sma); } if (semnum < 0 || semnum >= sma->sem_nsems) { rcu_read_unlock(); return -EINVAL; } if (ipcperms(ns, &sma->sem_perm, S_IWUGO)) { rcu_read_unlock(); return -EACCES; } |
e1fd1f490 get rid of union ... |
1276 1277 |
err = security_sem_semctl(sma, SETVAL); |
6062a8dc0 ipc,sem: fine gra... |
1278 1279 1280 1281 |
if (err) { rcu_read_unlock(); return -EACCES; } |
e1fd1f490 get rid of union ... |
1282 |
|
6062a8dc0 ipc,sem: fine gra... |
1283 |
sem_lock(sma, NULL, -1); |
e1fd1f490 get rid of union ... |
1284 |
|
0f3d2b013 ipc: introduce ip... |
1285 |
if (!ipc_valid_object(&sma->sem_perm)) { |
6e224f945 ipc/sem.c: synchr... |
1286 1287 1288 1289 |
sem_unlock(sma, -1); rcu_read_unlock(); return -EIDRM; } |
e1fd1f490 get rid of union ... |
1290 |
curr = &sma->sem_base[semnum]; |
cf9d5d78d ipc: close open c... |
1291 |
ipc_assert_locked_object(&sma->sem_perm); |
e1fd1f490 get rid of union ... |
1292 1293 1294 1295 1296 1297 1298 1299 |
list_for_each_entry(un, &sma->list_id, list_id) un->semadj[semnum] = 0; curr->semval = val; curr->sempid = task_tgid_vnr(current); sma->sem_ctime = get_seconds(); /* maybe some queued-up processes were waiting for this */ do_smart_update(sma, NULL, 0, 0, &tasks); |
6062a8dc0 ipc,sem: fine gra... |
1300 |
sem_unlock(sma, -1); |
6d49dab8a ipc: move rcu_rea... |
1301 |
rcu_read_unlock(); |
e1fd1f490 get rid of union ... |
1302 |
wake_up_sem_queue_do(&tasks); |
6062a8dc0 ipc,sem: fine gra... |
1303 |
return 0; |
e1fd1f490 get rid of union ... |
1304 |
} |
e38935341 [PATCH] IPC names... |
1305 |
static int semctl_main(struct ipc_namespace *ns, int semid, int semnum, |
e1fd1f490 get rid of union ... |
1306 |
int cmd, void __user *p) |
1da177e4c Linux-2.6.12-rc2 |
1307 1308 |
{ struct sem_array *sma; |
239521f31 ipc: whitespace c... |
1309 |
struct sem *curr; |
16df3674e ipc,sem: do not h... |
1310 |
int err, nsems; |
1da177e4c Linux-2.6.12-rc2 |
1311 |
ushort fast_sem_io[SEMMSL_FAST]; |
239521f31 ipc: whitespace c... |
1312 |
ushort *sem_io = fast_sem_io; |
0a2b9d4c7 ipc/sem.c: move w... |
1313 |
struct list_head tasks; |
1da177e4c Linux-2.6.12-rc2 |
1314 |
|
16df3674e ipc,sem: do not h... |
1315 1316 1317 1318 1319 1320 |
INIT_LIST_HEAD(&tasks); rcu_read_lock(); sma = sem_obtain_object_check(ns, semid); if (IS_ERR(sma)) { rcu_read_unlock(); |
023a53557 ipc: integrate ip... |
1321 |
return PTR_ERR(sma); |
16df3674e ipc,sem: do not h... |
1322 |
} |
1da177e4c Linux-2.6.12-rc2 |
1323 1324 |
nsems = sma->sem_nsems; |
1da177e4c Linux-2.6.12-rc2 |
1325 |
err = -EACCES; |
c728b9c87 ipc: simplify sem... |
1326 1327 |
if (ipcperms(ns, &sma->sem_perm, cmd == SETALL ? S_IWUGO : S_IRUGO)) goto out_rcu_wakeup; |
1da177e4c Linux-2.6.12-rc2 |
1328 1329 |
err = security_sem_semctl(sma, cmd); |
c728b9c87 ipc: simplify sem... |
1330 1331 |
if (err) goto out_rcu_wakeup; |
1da177e4c Linux-2.6.12-rc2 |
1332 1333 1334 1335 1336 |
err = -EACCES; switch (cmd) { case GETALL: { |
e1fd1f490 get rid of union ... |
1337 |
ushort __user *array = p; |
1da177e4c Linux-2.6.12-rc2 |
1338 |
int i; |
ce857229e ipc: fix GETALL/I... |
1339 |
sem_lock(sma, NULL, -1); |
0f3d2b013 ipc: introduce ip... |
1340 |
if (!ipc_valid_object(&sma->sem_perm)) { |
6e224f945 ipc/sem.c: synchr... |
1341 1342 1343 |
err = -EIDRM; goto out_unlock; } |
239521f31 ipc: whitespace c... |
1344 |
if (nsems > SEMMSL_FAST) { |
ce857229e ipc: fix GETALL/I... |
1345 |
if (!ipc_rcu_getref(sma)) { |
ce857229e ipc: fix GETALL/I... |
1346 |
err = -EIDRM; |
6e224f945 ipc/sem.c: synchr... |
1347 |
goto out_unlock; |
ce857229e ipc: fix GETALL/I... |
1348 1349 |
} sem_unlock(sma, -1); |
6d49dab8a ipc: move rcu_rea... |
1350 |
rcu_read_unlock(); |
1da177e4c Linux-2.6.12-rc2 |
1351 |
sem_io = ipc_alloc(sizeof(ushort)*nsems); |
239521f31 ipc: whitespace c... |
1352 |
if (sem_io == NULL) { |
9b24fef9f sysv, ipc: fix se... |
1353 |
ipc_rcu_putref(sma, sem_rcu_free); |
1da177e4c Linux-2.6.12-rc2 |
1354 1355 |
return -ENOMEM; } |
4091fd942 ipc: move the rcu... |
1356 |
rcu_read_lock(); |
6ff379721 IPC/semaphores: c... |
1357 |
sem_lock_and_putref(sma); |
0f3d2b013 ipc: introduce ip... |
1358 |
if (!ipc_valid_object(&sma->sem_perm)) { |
1da177e4c Linux-2.6.12-rc2 |
1359 |
err = -EIDRM; |
6e224f945 ipc/sem.c: synchr... |
1360 |
goto out_unlock; |
1da177e4c Linux-2.6.12-rc2 |
1361 |
} |
ce857229e ipc: fix GETALL/I... |
1362 |
} |
1da177e4c Linux-2.6.12-rc2 |
1363 1364 |
for (i = 0; i < sma->sem_nsems; i++) sem_io[i] = sma->sem_base[i].semval; |
6062a8dc0 ipc,sem: fine gra... |
1365 |
sem_unlock(sma, -1); |
6d49dab8a ipc: move rcu_rea... |
1366 |
rcu_read_unlock(); |
1da177e4c Linux-2.6.12-rc2 |
1367 |
err = 0; |
239521f31 ipc: whitespace c... |
1368 |
if (copy_to_user(array, sem_io, nsems*sizeof(ushort))) |
1da177e4c Linux-2.6.12-rc2 |
1369 1370 1371 1372 1373 1374 1375 |
err = -EFAULT; goto out_free; } case SETALL: { int i; struct sem_undo *un; |
6062a8dc0 ipc,sem: fine gra... |
1376 |
if (!ipc_rcu_getref(sma)) { |
6e224f945 ipc/sem.c: synchr... |
1377 1378 |
err = -EIDRM; goto out_rcu_wakeup; |
6062a8dc0 ipc,sem: fine gra... |
1379 |
} |
16df3674e ipc,sem: do not h... |
1380 |
rcu_read_unlock(); |
1da177e4c Linux-2.6.12-rc2 |
1381 |
|
239521f31 ipc: whitespace c... |
1382 |
if (nsems > SEMMSL_FAST) { |
1da177e4c Linux-2.6.12-rc2 |
1383 |
sem_io = ipc_alloc(sizeof(ushort)*nsems); |
239521f31 ipc: whitespace c... |
1384 |
if (sem_io == NULL) { |
9b24fef9f sysv, ipc: fix se... |
1385 |
ipc_rcu_putref(sma, sem_rcu_free); |
1da177e4c Linux-2.6.12-rc2 |
1386 1387 1388 |
return -ENOMEM; } } |
239521f31 ipc: whitespace c... |
1389 |
if (copy_from_user(sem_io, p, nsems*sizeof(ushort))) { |
9b24fef9f sysv, ipc: fix se... |
1390 |
ipc_rcu_putref(sma, sem_rcu_free); |
1da177e4c Linux-2.6.12-rc2 |
1391 1392 1393 1394 1395 1396 |
err = -EFAULT; goto out_free; } for (i = 0; i < nsems; i++) { if (sem_io[i] > SEMVMX) { |
9b24fef9f sysv, ipc: fix se... |
1397 |
ipc_rcu_putref(sma, sem_rcu_free); |
1da177e4c Linux-2.6.12-rc2 |
1398 1399 1400 1401 |
err = -ERANGE; goto out_free; } } |
4091fd942 ipc: move the rcu... |
1402 |
rcu_read_lock(); |
6ff379721 IPC/semaphores: c... |
1403 |
sem_lock_and_putref(sma); |
0f3d2b013 ipc: introduce ip... |
1404 |
if (!ipc_valid_object(&sma->sem_perm)) { |
1da177e4c Linux-2.6.12-rc2 |
1405 |
err = -EIDRM; |
6e224f945 ipc/sem.c: synchr... |
1406 |
goto out_unlock; |
1da177e4c Linux-2.6.12-rc2 |
1407 |
} |
a5f4db877 ipc/sem: make sem... |
1408 |
for (i = 0; i < nsems; i++) { |
1da177e4c Linux-2.6.12-rc2 |
1409 |
sma->sem_base[i].semval = sem_io[i]; |
a5f4db877 ipc/sem: make sem... |
1410 1411 |
sma->sem_base[i].sempid = task_tgid_vnr(current); } |
4daa28f6d ipc/sem.c: conver... |
1412 |
|
cf9d5d78d ipc: close open c... |
1413 |
ipc_assert_locked_object(&sma->sem_perm); |
4daa28f6d ipc/sem.c: conver... |
1414 |
list_for_each_entry(un, &sma->list_id, list_id) { |
1da177e4c Linux-2.6.12-rc2 |
1415 1416 |
for (i = 0; i < nsems; i++) un->semadj[i] = 0; |
4daa28f6d ipc/sem.c: conver... |
1417 |
} |
1da177e4c Linux-2.6.12-rc2 |
1418 1419 |
sma->sem_ctime = get_seconds(); /* maybe some queued-up processes were waiting for this */ |
0a2b9d4c7 ipc/sem.c: move w... |
1420 |
do_smart_update(sma, NULL, 0, 0, &tasks); |
1da177e4c Linux-2.6.12-rc2 |
1421 1422 1423 |
err = 0; goto out_unlock; } |
e1fd1f490 get rid of union ... |
1424 |
/* GETVAL, GETPID, GETNCTN, GETZCNT: fall-through */ |
1da177e4c Linux-2.6.12-rc2 |
1425 1426 |
} err = -EINVAL; |
c728b9c87 ipc: simplify sem... |
1427 1428 |
if (semnum < 0 || semnum >= nsems) goto out_rcu_wakeup; |
1da177e4c Linux-2.6.12-rc2 |
1429 |
|
6062a8dc0 ipc,sem: fine gra... |
1430 |
sem_lock(sma, NULL, -1); |
0f3d2b013 ipc: introduce ip... |
1431 |
if (!ipc_valid_object(&sma->sem_perm)) { |
6e224f945 ipc/sem.c: synchr... |
1432 1433 1434 |
err = -EIDRM; goto out_unlock; } |
1da177e4c Linux-2.6.12-rc2 |
1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 |
curr = &sma->sem_base[semnum]; switch (cmd) { case GETVAL: err = curr->semval; goto out_unlock; case GETPID: err = curr->sempid; goto out_unlock; case GETNCNT: |
2f2ed41dc ipc/sem.c: remove... |
1445 |
err = count_semcnt(sma, semnum, 0); |
1da177e4c Linux-2.6.12-rc2 |
1446 1447 |
goto out_unlock; case GETZCNT: |
2f2ed41dc ipc/sem.c: remove... |
1448 |
err = count_semcnt(sma, semnum, 1); |
1da177e4c Linux-2.6.12-rc2 |
1449 |
goto out_unlock; |
1da177e4c Linux-2.6.12-rc2 |
1450 |
} |
16df3674e ipc,sem: do not h... |
1451 |
|
1da177e4c Linux-2.6.12-rc2 |
1452 |
out_unlock: |
6062a8dc0 ipc,sem: fine gra... |
1453 |
sem_unlock(sma, -1); |
c728b9c87 ipc: simplify sem... |
1454 |
out_rcu_wakeup: |
6d49dab8a ipc: move rcu_rea... |
1455 |
rcu_read_unlock(); |
0a2b9d4c7 ipc/sem.c: move w... |
1456 |
wake_up_sem_queue_do(&tasks); |
1da177e4c Linux-2.6.12-rc2 |
1457 |
out_free: |
239521f31 ipc: whitespace c... |
1458 |
if (sem_io != fast_sem_io) |
1d5cfdb07 tree wide: use kv... |
1459 |
ipc_free(sem_io); |
1da177e4c Linux-2.6.12-rc2 |
1460 1461 |
return err; } |
016d7132f IPC: get rid of t... |
1462 1463 |
static inline unsigned long copy_semid_from_user(struct semid64_ds *out, void __user *buf, int version) |
1da177e4c Linux-2.6.12-rc2 |
1464 |
{ |
239521f31 ipc: whitespace c... |
1465 |
switch (version) { |
1da177e4c Linux-2.6.12-rc2 |
1466 |
case IPC_64: |
016d7132f IPC: get rid of t... |
1467 |
if (copy_from_user(out, buf, sizeof(*out))) |
1da177e4c Linux-2.6.12-rc2 |
1468 |
return -EFAULT; |
1da177e4c Linux-2.6.12-rc2 |
1469 |
return 0; |
1da177e4c Linux-2.6.12-rc2 |
1470 1471 1472 |
case IPC_OLD: { struct semid_ds tbuf_old; |
239521f31 ipc: whitespace c... |
1473 |
if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old))) |
1da177e4c Linux-2.6.12-rc2 |
1474 |
return -EFAULT; |
016d7132f IPC: get rid of t... |
1475 1476 1477 |
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; |
1da177e4c Linux-2.6.12-rc2 |
1478 1479 1480 1481 1482 1483 1484 |
return 0; } default: return -EINVAL; } } |
522bb2a2b IPC/semaphores: m... |
1485 |
/* |
d9a605e40 ipc: rename ids->... |
1486 |
* This function handles some semctl commands which require the rwsem |
522bb2a2b IPC/semaphores: m... |
1487 |
* to be held in write mode. |
d9a605e40 ipc: rename ids->... |
1488 |
* NOTE: no locks must be held, the rwsem is taken inside this function. |
522bb2a2b IPC/semaphores: m... |
1489 |
*/ |
21a4826a7 IPC/semaphores: r... |
1490 |
static int semctl_down(struct ipc_namespace *ns, int semid, |
e1fd1f490 get rid of union ... |
1491 |
int cmd, int version, void __user *p) |
1da177e4c Linux-2.6.12-rc2 |
1492 1493 1494 |
{ struct sem_array *sma; int err; |
016d7132f IPC: get rid of t... |
1495 |
struct semid64_ds semid64; |
1da177e4c Linux-2.6.12-rc2 |
1496 |
struct kern_ipc_perm *ipcp; |
239521f31 ipc: whitespace c... |
1497 |
if (cmd == IPC_SET) { |
e1fd1f490 get rid of union ... |
1498 |
if (copy_semid_from_user(&semid64, p, version)) |
1da177e4c Linux-2.6.12-rc2 |
1499 |
return -EFAULT; |
1da177e4c Linux-2.6.12-rc2 |
1500 |
} |
073115d6b [PATCH] Rework of... |
1501 |
|
d9a605e40 ipc: rename ids->... |
1502 |
down_write(&sem_ids(ns).rwsem); |
7b4cc5d84 ipc: move locking... |
1503 |
rcu_read_lock(); |
16df3674e ipc,sem: do not h... |
1504 1505 |
ipcp = ipcctl_pre_down_nolock(ns, &sem_ids(ns), semid, cmd, &semid64.sem_perm, 0); |
7b4cc5d84 ipc: move locking... |
1506 1507 |
if (IS_ERR(ipcp)) { err = PTR_ERR(ipcp); |
7b4cc5d84 ipc: move locking... |
1508 1509 |
goto out_unlock1; } |
073115d6b [PATCH] Rework of... |
1510 |
|
a5f75e7f2 IPC: consolidate ... |
1511 |
sma = container_of(ipcp, struct sem_array, sem_perm); |
1da177e4c Linux-2.6.12-rc2 |
1512 1513 |
err = security_sem_semctl(sma, cmd); |
7b4cc5d84 ipc: move locking... |
1514 1515 |
if (err) goto out_unlock1; |
1da177e4c Linux-2.6.12-rc2 |
1516 |
|
7b4cc5d84 ipc: move locking... |
1517 |
switch (cmd) { |
1da177e4c Linux-2.6.12-rc2 |
1518 |
case IPC_RMID: |
6062a8dc0 ipc,sem: fine gra... |
1519 |
sem_lock(sma, NULL, -1); |
7b4cc5d84 ipc: move locking... |
1520 |
/* freeary unlocks the ipc object and rcu */ |
01b8b07a5 IPC: consolidate ... |
1521 |
freeary(ns, ipcp); |
522bb2a2b IPC/semaphores: m... |
1522 |
goto out_up; |
1da177e4c Linux-2.6.12-rc2 |
1523 |
case IPC_SET: |
6062a8dc0 ipc,sem: fine gra... |
1524 |
sem_lock(sma, NULL, -1); |
1efdb69b0 userns: Convert i... |
1525 1526 |
err = ipc_update_perm(&semid64.sem_perm, ipcp); if (err) |
7b4cc5d84 ipc: move locking... |
1527 |
goto out_unlock0; |
1da177e4c Linux-2.6.12-rc2 |
1528 |
sma->sem_ctime = get_seconds(); |
1da177e4c Linux-2.6.12-rc2 |
1529 1530 |
break; default: |
1da177e4c Linux-2.6.12-rc2 |
1531 |
err = -EINVAL; |
7b4cc5d84 ipc: move locking... |
1532 |
goto out_unlock1; |
1da177e4c Linux-2.6.12-rc2 |
1533 |
} |
1da177e4c Linux-2.6.12-rc2 |
1534 |
|
7b4cc5d84 ipc: move locking... |
1535 |
out_unlock0: |
6062a8dc0 ipc,sem: fine gra... |
1536 |
sem_unlock(sma, -1); |
7b4cc5d84 ipc: move locking... |
1537 |
out_unlock1: |
6d49dab8a ipc: move rcu_rea... |
1538 |
rcu_read_unlock(); |
522bb2a2b IPC/semaphores: m... |
1539 |
out_up: |
d9a605e40 ipc: rename ids->... |
1540 |
up_write(&sem_ids(ns).rwsem); |
1da177e4c Linux-2.6.12-rc2 |
1541 1542 |
return err; } |
e1fd1f490 get rid of union ... |
1543 |
SYSCALL_DEFINE4(semctl, int, semid, int, semnum, int, cmd, unsigned long, arg) |
1da177e4c Linux-2.6.12-rc2 |
1544 |
{ |
1da177e4c Linux-2.6.12-rc2 |
1545 |
int version; |
e38935341 [PATCH] IPC names... |
1546 |
struct ipc_namespace *ns; |
e1fd1f490 get rid of union ... |
1547 |
void __user *p = (void __user *)arg; |
1da177e4c Linux-2.6.12-rc2 |
1548 1549 1550 1551 1552 |
if (semid < 0) return -EINVAL; version = ipc_parse_version(&cmd); |
e38935341 [PATCH] IPC names... |
1553 |
ns = current->nsproxy->ipc_ns; |
1da177e4c Linux-2.6.12-rc2 |
1554 |
|
239521f31 ipc: whitespace c... |
1555 |
switch (cmd) { |
1da177e4c Linux-2.6.12-rc2 |
1556 1557 |
case IPC_INFO: case SEM_INFO: |
4b9fcb0ec IPC/semaphores: c... |
1558 |
case IPC_STAT: |
1da177e4c Linux-2.6.12-rc2 |
1559 |
case SEM_STAT: |
e1fd1f490 get rid of union ... |
1560 |
return semctl_nolock(ns, semid, cmd, version, p); |
1da177e4c Linux-2.6.12-rc2 |
1561 1562 1563 1564 1565 |
case GETALL: case GETVAL: case GETPID: case GETNCNT: case GETZCNT: |
1da177e4c Linux-2.6.12-rc2 |
1566 |
case SETALL: |
e1fd1f490 get rid of union ... |
1567 1568 1569 |
return semctl_main(ns, semid, semnum, cmd, p); case SETVAL: return semctl_setval(ns, semid, semnum, arg); |
1da177e4c Linux-2.6.12-rc2 |
1570 1571 |
case IPC_RMID: case IPC_SET: |
e1fd1f490 get rid of union ... |
1572 |
return semctl_down(ns, semid, cmd, version, p); |
1da177e4c Linux-2.6.12-rc2 |
1573 1574 1575 1576 |
default: return -EINVAL; } } |
1da177e4c Linux-2.6.12-rc2 |
1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 |
/* 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 * * If this allocation and assignment succeeds, but later * portions of this code fail, there is no need to free the sem_undo_list. * Just let it stay associated with the task, and it'll be freed later * at exit time. * * This can block, so callers must hold no locks. */ static inline int get_undo_list(struct sem_undo_list **undo_listp) { struct sem_undo_list *undo_list; |
1da177e4c Linux-2.6.12-rc2 |
1591 1592 1593 |
undo_list = current->sysvsem.undo_list; if (!undo_list) { |
2453a3062 [PATCH] ipc: repl... |
1594 |
undo_list = kzalloc(sizeof(*undo_list), GFP_KERNEL); |
1da177e4c Linux-2.6.12-rc2 |
1595 1596 |
if (undo_list == NULL) return -ENOMEM; |
00a5dfdb9 [PATCH] Fix semun... |
1597 |
spin_lock_init(&undo_list->lock); |
1da177e4c Linux-2.6.12-rc2 |
1598 |
atomic_set(&undo_list->refcnt, 1); |
4daa28f6d ipc/sem.c: conver... |
1599 |
INIT_LIST_HEAD(&undo_list->list_proc); |
1da177e4c Linux-2.6.12-rc2 |
1600 1601 1602 1603 1604 |
current->sysvsem.undo_list = undo_list; } *undo_listp = undo_list; return 0; } |
bf17bb717 ipc/sem.c: sem op... |
1605 |
static struct sem_undo *__lookup_undo(struct sem_undo_list *ulp, int semid) |
1da177e4c Linux-2.6.12-rc2 |
1606 |
{ |
bf17bb717 ipc/sem.c: sem op... |
1607 |
struct sem_undo *un; |
4daa28f6d ipc/sem.c: conver... |
1608 |
|
bf17bb717 ipc/sem.c: sem op... |
1609 1610 1611 |
list_for_each_entry_rcu(un, &ulp->list_proc, list_proc) { if (un->semid == semid) return un; |
1da177e4c Linux-2.6.12-rc2 |
1612 |
} |
4daa28f6d ipc/sem.c: conver... |
1613 |
return NULL; |
1da177e4c Linux-2.6.12-rc2 |
1614 |
} |
bf17bb717 ipc/sem.c: sem op... |
1615 1616 1617 |
static struct sem_undo *lookup_undo(struct sem_undo_list *ulp, int semid) { struct sem_undo *un; |
239521f31 ipc: whitespace c... |
1618 |
assert_spin_locked(&ulp->lock); |
bf17bb717 ipc/sem.c: sem op... |
1619 1620 1621 1622 1623 1624 1625 1626 |
un = __lookup_undo(ulp, semid); if (un) { list_del_rcu(&un->list_proc); list_add_rcu(&un->list_proc, &ulp->list_proc); } return un; } |
4daa28f6d ipc/sem.c: conver... |
1627 |
/** |
8001c8581 ipc: standardize ... |
1628 |
* find_alloc_undo - lookup (and if not present create) undo array |
4daa28f6d ipc/sem.c: conver... |
1629 1630 1631 1632 1633 1634 |
* @ns: namespace * @semid: semaphore array id * * The function looks up (and if not present creates) the undo structure. * The size of the undo structure depends on the size of the semaphore * array, thus the alloc path is not that straightforward. |
380af1b33 ipc/sem.c: rewrit... |
1635 1636 |
* Lifetime-rules: sem_undo is rcu-protected, on success, the function * performs a rcu_read_lock(). |
4daa28f6d ipc/sem.c: conver... |
1637 1638 |
*/ static struct sem_undo *find_alloc_undo(struct ipc_namespace *ns, int semid) |
1da177e4c Linux-2.6.12-rc2 |
1639 1640 1641 1642 |
{ struct sem_array *sma; struct sem_undo_list *ulp; struct sem_undo *un, *new; |
6062a8dc0 ipc,sem: fine gra... |
1643 |
int nsems, error; |
1da177e4c Linux-2.6.12-rc2 |
1644 1645 1646 1647 |
error = get_undo_list(&ulp); if (error) return ERR_PTR(error); |
380af1b33 ipc/sem.c: rewrit... |
1648 |
rcu_read_lock(); |
c530c6ac7 IPC: cleanup some... |
1649 |
spin_lock(&ulp->lock); |
1da177e4c Linux-2.6.12-rc2 |
1650 |
un = lookup_undo(ulp, semid); |
c530c6ac7 IPC: cleanup some... |
1651 |
spin_unlock(&ulp->lock); |
239521f31 ipc: whitespace c... |
1652 |
if (likely(un != NULL)) |
1da177e4c Linux-2.6.12-rc2 |
1653 1654 1655 |
goto out; /* no undo structure around - allocate one. */ |
4daa28f6d ipc/sem.c: conver... |
1656 |
/* step 1: figure out the size of the semaphore array */ |
16df3674e ipc,sem: do not h... |
1657 1658 1659 |
sma = sem_obtain_object_check(ns, semid); if (IS_ERR(sma)) { rcu_read_unlock(); |
4de85cd6d ipc/sem.c: use ER... |
1660 |
return ERR_CAST(sma); |
16df3674e ipc,sem: do not h... |
1661 |
} |
023a53557 ipc: integrate ip... |
1662 |
|
1da177e4c Linux-2.6.12-rc2 |
1663 |
nsems = sma->sem_nsems; |
6062a8dc0 ipc,sem: fine gra... |
1664 1665 1666 1667 1668 |
if (!ipc_rcu_getref(sma)) { rcu_read_unlock(); un = ERR_PTR(-EIDRM); goto out; } |
16df3674e ipc,sem: do not h... |
1669 |
rcu_read_unlock(); |
1da177e4c Linux-2.6.12-rc2 |
1670 |
|
4daa28f6d ipc/sem.c: conver... |
1671 |
/* step 2: allocate new undo structure */ |
4668edc33 [PATCH] kernel co... |
1672 |
new = kzalloc(sizeof(struct sem_undo) + sizeof(short)*nsems, GFP_KERNEL); |
1da177e4c Linux-2.6.12-rc2 |
1673 |
if (!new) { |
9b24fef9f sysv, ipc: fix se... |
1674 |
ipc_rcu_putref(sma, sem_rcu_free); |
1da177e4c Linux-2.6.12-rc2 |
1675 1676 |
return ERR_PTR(-ENOMEM); } |
1da177e4c Linux-2.6.12-rc2 |
1677 |
|
380af1b33 ipc/sem.c: rewrit... |
1678 |
/* step 3: Acquire the lock on semaphore array */ |
4091fd942 ipc: move the rcu... |
1679 |
rcu_read_lock(); |
6ff379721 IPC/semaphores: c... |
1680 |
sem_lock_and_putref(sma); |
0f3d2b013 ipc: introduce ip... |
1681 |
if (!ipc_valid_object(&sma->sem_perm)) { |
6062a8dc0 ipc,sem: fine gra... |
1682 |
sem_unlock(sma, -1); |
6d49dab8a ipc: move rcu_rea... |
1683 |
rcu_read_unlock(); |
1da177e4c Linux-2.6.12-rc2 |
1684 1685 1686 1687 |
kfree(new); un = ERR_PTR(-EIDRM); goto out; } |
380af1b33 ipc/sem.c: rewrit... |
1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 |
spin_lock(&ulp->lock); /* * step 4: check for races: did someone else allocate the undo struct? */ un = lookup_undo(ulp, semid); if (un) { kfree(new); goto success; } |
4daa28f6d ipc/sem.c: conver... |
1698 1699 |
/* step 5: initialize & link new undo structure */ new->semadj = (short *) &new[1]; |
380af1b33 ipc/sem.c: rewrit... |
1700 |
new->ulp = ulp; |
4daa28f6d ipc/sem.c: conver... |
1701 1702 |
new->semid = semid; assert_spin_locked(&ulp->lock); |
380af1b33 ipc/sem.c: rewrit... |
1703 |
list_add_rcu(&new->list_proc, &ulp->list_proc); |
cf9d5d78d ipc: close open c... |
1704 |
ipc_assert_locked_object(&sma->sem_perm); |
4daa28f6d ipc/sem.c: conver... |
1705 |
list_add(&new->list_id, &sma->list_id); |
380af1b33 ipc/sem.c: rewrit... |
1706 |
un = new; |
4daa28f6d ipc/sem.c: conver... |
1707 |
|
380af1b33 ipc/sem.c: rewrit... |
1708 |
success: |
c530c6ac7 IPC: cleanup some... |
1709 |
spin_unlock(&ulp->lock); |
6062a8dc0 ipc,sem: fine gra... |
1710 |
sem_unlock(sma, -1); |
1da177e4c Linux-2.6.12-rc2 |
1711 1712 1713 |
out: return un; } |
c61284e99 ipc/sem.c: bugfix... |
1714 1715 |
/** |
8001c8581 ipc: standardize ... |
1716 |
* get_queue_result - retrieve the result code from sem_queue |
c61284e99 ipc/sem.c: bugfix... |
1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 |
* @q: Pointer to queue structure * * Retrieve the return code from the pending queue. If IN_WAKEUP is found in * q->status, then we must loop until the value is replaced with the final * value: This may happen if a task is woken up by an unrelated event (e.g. * signal) and in parallel the task is woken up by another task because it got * the requested semaphores. * * The function can be called with or without holding the semaphore spinlock. */ static int get_queue_result(struct sem_queue *q) { int error; error = q->status; while (unlikely(error == IN_WAKEUP)) { cpu_relax(); error = q->status; } return error; } |
d5460c997 [CVE-2009-0029] S... |
1739 1740 |
SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsops, unsigned, nsops, const struct timespec __user *, timeout) |
1da177e4c Linux-2.6.12-rc2 |
1741 1742 1743 1744 |
{ int error = -EINVAL; struct sem_array *sma; struct sembuf fast_sops[SEMOPM_FAST]; |
239521f31 ipc: whitespace c... |
1745 |
struct sembuf *sops = fast_sops, *sop; |
1da177e4c Linux-2.6.12-rc2 |
1746 |
struct sem_undo *un; |
6062a8dc0 ipc,sem: fine gra... |
1747 |
int undos = 0, alter = 0, max, locknum; |
1da177e4c Linux-2.6.12-rc2 |
1748 1749 |
struct sem_queue queue; unsigned long jiffies_left = 0; |
e38935341 [PATCH] IPC names... |
1750 |
struct ipc_namespace *ns; |
0a2b9d4c7 ipc/sem.c: move w... |
1751 |
struct list_head tasks; |
e38935341 [PATCH] IPC names... |
1752 1753 |
ns = current->nsproxy->ipc_ns; |
1da177e4c Linux-2.6.12-rc2 |
1754 1755 1756 |
if (nsops < 1 || semid < 0) return -EINVAL; |
e38935341 [PATCH] IPC names... |
1757 |
if (nsops > ns->sc_semopm) |
1da177e4c Linux-2.6.12-rc2 |
1758 |
return -E2BIG; |
239521f31 ipc: whitespace c... |
1759 1760 1761 |
if (nsops > SEMOPM_FAST) { sops = kmalloc(sizeof(*sops)*nsops, GFP_KERNEL); if (sops == NULL) |
1da177e4c Linux-2.6.12-rc2 |
1762 1763 |
return -ENOMEM; } |
239521f31 ipc: whitespace c... |
1764 1765 |
if (copy_from_user(sops, tsops, nsops * sizeof(*tsops))) { error = -EFAULT; |
1da177e4c Linux-2.6.12-rc2 |
1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 |
goto out_free; } if (timeout) { struct timespec _timeout; if (copy_from_user(&_timeout, timeout, sizeof(*timeout))) { error = -EFAULT; goto out_free; } if (_timeout.tv_sec < 0 || _timeout.tv_nsec < 0 || _timeout.tv_nsec >= 1000000000L) { error = -EINVAL; goto out_free; } jiffies_left = timespec_to_jiffies(&_timeout); } max = 0; for (sop = sops; sop < sops + nsops; sop++) { if (sop->sem_num >= max) max = sop->sem_num; if (sop->sem_flg & SEM_UNDO) |
b78755abc [PATCH] ipcsem: r... |
1786 1787 |
undos = 1; if (sop->sem_op != 0) |
1da177e4c Linux-2.6.12-rc2 |
1788 1789 |
alter = 1; } |
1da177e4c Linux-2.6.12-rc2 |
1790 |
|
6062a8dc0 ipc,sem: fine gra... |
1791 |
INIT_LIST_HEAD(&tasks); |
1da177e4c Linux-2.6.12-rc2 |
1792 |
if (undos) { |
6062a8dc0 ipc,sem: fine gra... |
1793 |
/* On success, find_alloc_undo takes the rcu_read_lock */ |
4daa28f6d ipc/sem.c: conver... |
1794 |
un = find_alloc_undo(ns, semid); |
1da177e4c Linux-2.6.12-rc2 |
1795 1796 1797 1798 |
if (IS_ERR(un)) { error = PTR_ERR(un); goto out_free; } |
6062a8dc0 ipc,sem: fine gra... |
1799 |
} else { |
1da177e4c Linux-2.6.12-rc2 |
1800 |
un = NULL; |
6062a8dc0 ipc,sem: fine gra... |
1801 1802 |
rcu_read_lock(); } |
1da177e4c Linux-2.6.12-rc2 |
1803 |
|
16df3674e ipc,sem: do not h... |
1804 |
sma = sem_obtain_object_check(ns, semid); |
023a53557 ipc: integrate ip... |
1805 |
if (IS_ERR(sma)) { |
6062a8dc0 ipc,sem: fine gra... |
1806 |
rcu_read_unlock(); |
023a53557 ipc: integrate ip... |
1807 |
error = PTR_ERR(sma); |
1da177e4c Linux-2.6.12-rc2 |
1808 |
goto out_free; |
023a53557 ipc: integrate ip... |
1809 |
} |
16df3674e ipc,sem: do not h... |
1810 |
error = -EFBIG; |
c728b9c87 ipc: simplify sem... |
1811 1812 |
if (max >= sma->sem_nsems) goto out_rcu_wakeup; |
16df3674e ipc,sem: do not h... |
1813 1814 |
error = -EACCES; |
c728b9c87 ipc: simplify sem... |
1815 1816 |
if (ipcperms(ns, &sma->sem_perm, alter ? S_IWUGO : S_IRUGO)) goto out_rcu_wakeup; |
16df3674e ipc,sem: do not h... |
1817 1818 |
error = security_sem_semop(sma, sops, nsops, alter); |
c728b9c87 ipc: simplify sem... |
1819 1820 |
if (error) goto out_rcu_wakeup; |
16df3674e ipc,sem: do not h... |
1821 |
|
6e224f945 ipc/sem.c: synchr... |
1822 1823 |
error = -EIDRM; locknum = sem_lock(sma, sops, nsops); |
0f3d2b013 ipc: introduce ip... |
1824 1825 1826 1827 1828 1829 1830 1831 1832 |
/* * We eventually might perform the following check in a lockless * fashion, considering ipc_valid_object() locking constraints. * If nsops == 1 and there is no contention for sem_perm.lock, then * only a per-semaphore lock is held and it's OK to proceed with the * check below. More details on the fine grained locking scheme * entangled here and why it's RMID race safe on comments at sem_lock() */ if (!ipc_valid_object(&sma->sem_perm)) |
6e224f945 ipc/sem.c: synchr... |
1833 |
goto out_unlock_free; |
1da177e4c Linux-2.6.12-rc2 |
1834 |
/* |
4daa28f6d ipc/sem.c: conver... |
1835 |
* semid identifiers are not unique - find_alloc_undo may have |
1da177e4c Linux-2.6.12-rc2 |
1836 |
* allocated an undo structure, it was invalidated by an RMID |
4daa28f6d ipc/sem.c: conver... |
1837 |
* and now a new array with received the same id. Check and fail. |
25985edce Fix common misspe... |
1838 |
* This case can be detected checking un->semid. The existence of |
380af1b33 ipc/sem.c: rewrit... |
1839 |
* "un" itself is guaranteed by rcu. |
1da177e4c Linux-2.6.12-rc2 |
1840 |
*/ |
6062a8dc0 ipc,sem: fine gra... |
1841 1842 |
if (un && un->semid == -1) goto out_unlock_free; |
4daa28f6d ipc/sem.c: conver... |
1843 |
|
d198cd6d6 ipc/sem.c: change... |
1844 1845 1846 1847 1848 1849 1850 |
queue.sops = sops; queue.nsops = nsops; queue.undo = un; queue.pid = task_tgid_vnr(current); queue.alter = alter; error = perform_atomic_semop(sma, &queue); |
0e8c66569 ipc/sem.c: update... |
1851 1852 1853 1854 1855 |
if (error == 0) { /* If the operation was successful, then do * the required updates. */ if (alter) |
0a2b9d4c7 ipc/sem.c: move w... |
1856 |
do_smart_update(sma, sops, nsops, 1, &tasks); |
0e8c66569 ipc/sem.c: update... |
1857 1858 |
else set_semotime(sma, sops); |
1da177e4c Linux-2.6.12-rc2 |
1859 |
} |
0e8c66569 ipc/sem.c: update... |
1860 1861 |
if (error <= 0) goto out_unlock_free; |
1da177e4c Linux-2.6.12-rc2 |
1862 1863 1864 1865 |
/* We need to sleep on this operation, so we put the current * task into the pending queue and go to sleep. */ |
46c0a8ca3 ipc, kernel: clea... |
1866 |
|
b97e820ff ipc/sem.c: add a ... |
1867 1868 1869 |
if (nsops == 1) { struct sem *curr; curr = &sma->sem_base[sops->sem_num]; |
f269f40ad ipc/sem.c: always... |
1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 |
if (alter) { if (sma->complex_count) { list_add_tail(&queue.list, &sma->pending_alter); } else { list_add_tail(&queue.list, &curr->pending_alter); } } else { |
1a82e9e1d ipc/sem: separate... |
1880 |
list_add_tail(&queue.list, &curr->pending_const); |
f269f40ad ipc/sem.c: always... |
1881 |
} |
b97e820ff ipc/sem.c: add a ... |
1882 |
} else { |
f269f40ad ipc/sem.c: always... |
1883 1884 |
if (!sma->complex_count) merge_queues(sma); |
9f1bc2c90 ipc,sem: have onl... |
1885 |
if (alter) |
1a82e9e1d ipc/sem: separate... |
1886 |
list_add_tail(&queue.list, &sma->pending_alter); |
9f1bc2c90 ipc,sem: have onl... |
1887 |
else |
1a82e9e1d ipc/sem: separate... |
1888 |
list_add_tail(&queue.list, &sma->pending_const); |
b97e820ff ipc/sem.c: add a ... |
1889 1890 |
sma->complex_count++; } |
1da177e4c Linux-2.6.12-rc2 |
1891 1892 |
queue.status = -EINTR; queue.sleeper = current; |
0b0577f60 ipc/sem.c: handle... |
1893 1894 |
sleep_again: |
52644c9ab ipc,sem: use curr... |
1895 |
__set_current_state(TASK_INTERRUPTIBLE); |
6062a8dc0 ipc,sem: fine gra... |
1896 |
sem_unlock(sma, locknum); |
6d49dab8a ipc: move rcu_rea... |
1897 |
rcu_read_unlock(); |
1da177e4c Linux-2.6.12-rc2 |
1898 1899 1900 1901 1902 |
if (timeout) jiffies_left = schedule_timeout(jiffies_left); else schedule(); |
c61284e99 ipc/sem.c: bugfix... |
1903 |
error = get_queue_result(&queue); |
1da177e4c Linux-2.6.12-rc2 |
1904 1905 1906 |
if (error != -EINTR) { /* fast path: update_queue already obtained all requested |
c61284e99 ipc/sem.c: bugfix... |
1907 1908 1909 1910 1911 1912 1913 |
* resources. * Perform a smp_mb(): User space could assume that semop() * is a memory barrier: Without the mb(), the cpu could * speculatively read in user space stale data that was * overwritten by the previous owner of the semaphore. */ smp_mb(); |
1da177e4c Linux-2.6.12-rc2 |
1914 1915 |
goto out_free; } |
321310ced ipc: move sem_obt... |
1916 |
rcu_read_lock(); |
6062a8dc0 ipc,sem: fine gra... |
1917 |
sma = sem_obtain_lock(ns, semid, sops, nsops, &locknum); |
d694ad62b ipc/sem.c: fix ra... |
1918 1919 1920 1921 1922 1923 1924 1925 1926 |
/* * Wait until it's guaranteed that no wakeup_sem_queue_do() is ongoing. */ error = get_queue_result(&queue); /* * Array removed? If yes, leave without sem_unlock(). */ |
023a53557 ipc: integrate ip... |
1927 |
if (IS_ERR(sma)) { |
321310ced ipc: move sem_obt... |
1928 |
rcu_read_unlock(); |
1da177e4c Linux-2.6.12-rc2 |
1929 1930 |
goto out_free; } |
c61284e99 ipc/sem.c: bugfix... |
1931 |
|
1da177e4c Linux-2.6.12-rc2 |
1932 |
/* |
d694ad62b ipc/sem.c: fix ra... |
1933 1934 |
* If queue.status != -EINTR we are woken up by another process. * Leave without unlink_queue(), but with sem_unlock(). |
1da177e4c Linux-2.6.12-rc2 |
1935 |
*/ |
3ab08fe20 ipc: remove brace... |
1936 |
if (error != -EINTR) |
1da177e4c Linux-2.6.12-rc2 |
1937 |
goto out_unlock_free; |
1da177e4c Linux-2.6.12-rc2 |
1938 1939 1940 1941 1942 1943 |
/* * If an interrupt occurred we have to clean up the queue */ if (timeout && jiffies_left == 0) error = -EAGAIN; |
0b0577f60 ipc/sem.c: handle... |
1944 1945 1946 1947 1948 1949 |
/* * If the wakeup was spurious, just retry */ if (error == -EINTR && !signal_pending(current)) goto sleep_again; |
b97e820ff ipc/sem.c: add a ... |
1950 |
unlink_queue(sma, &queue); |
1da177e4c Linux-2.6.12-rc2 |
1951 1952 |
out_unlock_free: |
6062a8dc0 ipc,sem: fine gra... |
1953 |
sem_unlock(sma, locknum); |
c728b9c87 ipc: simplify sem... |
1954 |
out_rcu_wakeup: |
6d49dab8a ipc: move rcu_rea... |
1955 |
rcu_read_unlock(); |
0a2b9d4c7 ipc/sem.c: move w... |
1956 |
wake_up_sem_queue_do(&tasks); |
1da177e4c Linux-2.6.12-rc2 |
1957 |
out_free: |
239521f31 ipc: whitespace c... |
1958 |
if (sops != fast_sops) |
1da177e4c Linux-2.6.12-rc2 |
1959 1960 1961 |
kfree(sops); return error; } |
d5460c997 [CVE-2009-0029] S... |
1962 1963 |
SYSCALL_DEFINE3(semop, int, semid, struct sembuf __user *, tsops, unsigned, nsops) |
1da177e4c Linux-2.6.12-rc2 |
1964 1965 1966 1967 1968 1969 |
{ return sys_semtimedop(semid, tsops, nsops, NULL); } /* If CLONE_SYSVSEM is set, establish sharing of SEM_UNDO state between * parent and child tasks. |
1da177e4c Linux-2.6.12-rc2 |
1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 |
*/ int copy_semundo(unsigned long clone_flags, struct task_struct *tsk) { struct sem_undo_list *undo_list; int error; if (clone_flags & CLONE_SYSVSEM) { error = get_undo_list(&undo_list); if (error) return error; |
1da177e4c Linux-2.6.12-rc2 |
1981 1982 |
atomic_inc(&undo_list->refcnt); tsk->sysvsem.undo_list = undo_list; |
46c0a8ca3 ipc, kernel: clea... |
1983 |
} else |
1da177e4c Linux-2.6.12-rc2 |
1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 |
tsk->sysvsem.undo_list = NULL; return 0; } /* * add semadj values to semaphores, free undo structures. * undo structures are not freed when semaphore arrays are destroyed * so some of them may be out of date. * IMPLEMENTATION NOTE: There is some confusion over whether the * set of adjustments that needs to be done should be done in an atomic * manner or not. That is, if we are attempting to decrement the semval * should we queue up and wait until we can do so legally? * The original implementation attempted to do this (queue and wait). * The current implementation does not do so. The POSIX standard * and SVID should be consulted to determine what behavior is mandated. */ void exit_sem(struct task_struct *tsk) { |
4daa28f6d ipc/sem.c: conver... |
2003 |
struct sem_undo_list *ulp; |
1da177e4c Linux-2.6.12-rc2 |
2004 |
|
4daa28f6d ipc/sem.c: conver... |
2005 2006 |
ulp = tsk->sysvsem.undo_list; if (!ulp) |
1da177e4c Linux-2.6.12-rc2 |
2007 |
return; |
9edff4ab1 ipc: sysvsem: imp... |
2008 |
tsk->sysvsem.undo_list = NULL; |
1da177e4c Linux-2.6.12-rc2 |
2009 |
|
4daa28f6d ipc/sem.c: conver... |
2010 |
if (!atomic_dec_and_test(&ulp->refcnt)) |
1da177e4c Linux-2.6.12-rc2 |
2011 |
return; |
380af1b33 ipc/sem.c: rewrit... |
2012 |
for (;;) { |
1da177e4c Linux-2.6.12-rc2 |
2013 |
struct sem_array *sma; |
380af1b33 ipc/sem.c: rewrit... |
2014 |
struct sem_undo *un; |
0a2b9d4c7 ipc/sem.c: move w... |
2015 |
struct list_head tasks; |
6062a8dc0 ipc,sem: fine gra... |
2016 |
int semid, i; |
4daa28f6d ipc/sem.c: conver... |
2017 |
|
2a1613a58 ipc/sem.c: add co... |
2018 |
cond_resched(); |
380af1b33 ipc/sem.c: rewrit... |
2019 |
rcu_read_lock(); |
05725f7eb rculist: use list... |
2020 2021 |
un = list_entry_rcu(ulp->list_proc.next, struct sem_undo, list_proc); |
602b8593d ipc,sem: fix use ... |
2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 |
if (&un->list_proc == &ulp->list_proc) { /* * We must wait for freeary() before freeing this ulp, * in case we raced with last sem_undo. There is a small * possibility where we exit while freeary() didn't * finish unlocking sem_undo_list. */ spin_unlock_wait(&ulp->lock); rcu_read_unlock(); break; } spin_lock(&ulp->lock); semid = un->semid; spin_unlock(&ulp->lock); |
4daa28f6d ipc/sem.c: conver... |
2036 |
|
602b8593d ipc,sem: fix use ... |
2037 |
/* exit_sem raced with IPC_RMID, nothing to do */ |
6062a8dc0 ipc,sem: fine gra... |
2038 2039 |
if (semid == -1) { rcu_read_unlock(); |
602b8593d ipc,sem: fix use ... |
2040 |
continue; |
6062a8dc0 ipc,sem: fine gra... |
2041 |
} |
1da177e4c Linux-2.6.12-rc2 |
2042 |
|
602b8593d ipc,sem: fix use ... |
2043 |
sma = sem_obtain_object_check(tsk->nsproxy->ipc_ns, semid); |
380af1b33 ipc/sem.c: rewrit... |
2044 |
/* exit_sem raced with IPC_RMID, nothing to do */ |
6062a8dc0 ipc,sem: fine gra... |
2045 2046 |
if (IS_ERR(sma)) { rcu_read_unlock(); |
380af1b33 ipc/sem.c: rewrit... |
2047 |
continue; |
6062a8dc0 ipc,sem: fine gra... |
2048 |
} |
1da177e4c Linux-2.6.12-rc2 |
2049 |
|
6062a8dc0 ipc,sem: fine gra... |
2050 |
sem_lock(sma, NULL, -1); |
6e224f945 ipc/sem.c: synchr... |
2051 |
/* exit_sem raced with IPC_RMID, nothing to do */ |
0f3d2b013 ipc: introduce ip... |
2052 |
if (!ipc_valid_object(&sma->sem_perm)) { |
6e224f945 ipc/sem.c: synchr... |
2053 2054 2055 2056 |
sem_unlock(sma, -1); rcu_read_unlock(); continue; } |
bf17bb717 ipc/sem.c: sem op... |
2057 |
un = __lookup_undo(ulp, semid); |
380af1b33 ipc/sem.c: rewrit... |
2058 2059 2060 2061 |
if (un == NULL) { /* exit_sem raced with IPC_RMID+semget() that created * exactly the same semid. Nothing to do. */ |
6062a8dc0 ipc,sem: fine gra... |
2062 |
sem_unlock(sma, -1); |
6d49dab8a ipc: move rcu_rea... |
2063 |
rcu_read_unlock(); |
380af1b33 ipc/sem.c: rewrit... |
2064 2065 2066 2067 |
continue; } /* remove un from the linked lists */ |
cf9d5d78d ipc: close open c... |
2068 |
ipc_assert_locked_object(&sma->sem_perm); |
4daa28f6d ipc/sem.c: conver... |
2069 |
list_del(&un->list_id); |
a97955844 ipc,sem: remove u... |
2070 2071 2072 2073 |
/* we are the last process using this ulp, acquiring ulp->lock * isn't required. Besides that, we are also protected against * IPC_RMID as we hold sma->sem_perm lock now */ |
380af1b33 ipc/sem.c: rewrit... |
2074 |
list_del_rcu(&un->list_proc); |
380af1b33 ipc/sem.c: rewrit... |
2075 |
|
4daa28f6d ipc/sem.c: conver... |
2076 2077 |
/* perform adjustments registered in un */ for (i = 0; i < sma->sem_nsems; i++) { |
239521f31 ipc: whitespace c... |
2078 |
struct sem *semaphore = &sma->sem_base[i]; |
4daa28f6d ipc/sem.c: conver... |
2079 2080 |
if (un->semadj[i]) { semaphore->semval += un->semadj[i]; |
1da177e4c Linux-2.6.12-rc2 |
2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 |
/* * Range checks of the new semaphore value, * not defined by sus: * - Some unices ignore the undo entirely * (e.g. HP UX 11i 11.22, Tru64 V5.1) * - some cap the value (e.g. FreeBSD caps * at 0, but doesn't enforce SEMVMX) * * Linux caps the semaphore value, both at 0 * and at SEMVMX. * |
239521f31 ipc: whitespace c... |
2092 |
* Manfred <manfred@colorfullife.com> |
1da177e4c Linux-2.6.12-rc2 |
2093 |
*/ |
5f921ae96 [PATCH] sem2mutex... |
2094 2095 2096 2097 |
if (semaphore->semval < 0) semaphore->semval = 0; if (semaphore->semval > SEMVMX) semaphore->semval = SEMVMX; |
b488893a3 pid namespaces: c... |
2098 |
semaphore->sempid = task_tgid_vnr(current); |
1da177e4c Linux-2.6.12-rc2 |
2099 2100 |
} } |
1da177e4c Linux-2.6.12-rc2 |
2101 |
/* maybe some queued-up processes were waiting for this */ |
0a2b9d4c7 ipc/sem.c: move w... |
2102 2103 |
INIT_LIST_HEAD(&tasks); do_smart_update(sma, NULL, 0, 1, &tasks); |
6062a8dc0 ipc,sem: fine gra... |
2104 |
sem_unlock(sma, -1); |
6d49dab8a ipc: move rcu_rea... |
2105 |
rcu_read_unlock(); |
0a2b9d4c7 ipc/sem.c: move w... |
2106 |
wake_up_sem_queue_do(&tasks); |
380af1b33 ipc/sem.c: rewrit... |
2107 |
|
693a8b6ee ipc,rcu: Convert ... |
2108 |
kfree_rcu(un, rcu); |
1da177e4c Linux-2.6.12-rc2 |
2109 |
} |
4daa28f6d ipc/sem.c: conver... |
2110 |
kfree(ulp); |
1da177e4c Linux-2.6.12-rc2 |
2111 2112 2113 |
} #ifdef CONFIG_PROC_FS |
19b4946ca [PATCH] ipc: conv... |
2114 |
static int sysvipc_sem_proc_show(struct seq_file *s, void *it) |
1da177e4c Linux-2.6.12-rc2 |
2115 |
{ |
1efdb69b0 userns: Convert i... |
2116 |
struct user_namespace *user_ns = seq_user_ns(s); |
19b4946ca [PATCH] ipc: conv... |
2117 |
struct sem_array *sma = it; |
d12e1e50e ipc/sem.c: replac... |
2118 |
time_t sem_otime; |
d8c633766 ipc/sem.c: synchr... |
2119 2120 2121 |
/* * The proc interface isn't aware of sem_lock(), it calls * ipc_lock_object() directly (in sysvipc_find_ipc). |
5864a2fd3 ipc/sem.c: fix co... |
2122 2123 |
* In order to stay compatible with sem_lock(), we must * enter / leave complex_mode. |
d8c633766 ipc/sem.c: synchr... |
2124 |
*/ |
5864a2fd3 ipc/sem.c: fix co... |
2125 |
complexmode_enter(sma); |
d8c633766 ipc/sem.c: synchr... |
2126 |
|
d12e1e50e ipc/sem.c: replac... |
2127 |
sem_otime = get_semotime(sma); |
19b4946ca [PATCH] ipc: conv... |
2128 |
|
7f032d6ef ipc: remove use o... |
2129 2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 |
seq_printf(s, "%10d %10d %4o %10u %5u %5u %5u %5u %10lu %10lu ", sma->sem_perm.key, sma->sem_perm.id, sma->sem_perm.mode, sma->sem_nsems, from_kuid_munged(user_ns, sma->sem_perm.uid), from_kgid_munged(user_ns, sma->sem_perm.gid), from_kuid_munged(user_ns, sma->sem_perm.cuid), from_kgid_munged(user_ns, sma->sem_perm.cgid), sem_otime, sma->sem_ctime); |
5864a2fd3 ipc/sem.c: fix co... |
2142 |
complexmode_tryleave(sma); |
7f032d6ef ipc: remove use o... |
2143 |
return 0; |
1da177e4c Linux-2.6.12-rc2 |
2144 2145 |
} #endif |