ipc: unify the syscalls code
This patch introduces a change into the sys_msgget(), sys_semget() and
sys_shmget() routines: they now share a common code, which is better for
maintainability.
Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/ipc/msg.c b/ipc/msg.c
index 08591a0..c2ee26f 100644
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -81,7 +81,7 @@
ipc_buildid(&msg_ids(ns), id, seq)
static void freeque(struct ipc_namespace *, struct msg_queue *);
-static int newque (struct ipc_namespace *ns, key_t key, int msgflg);
+static int newque(struct ipc_namespace *, struct ipc_params *);
#ifdef CONFIG_PROC_FS
static int sysvipc_msg_proc_show(struct seq_file *s, void *it);
#endif
@@ -144,10 +144,12 @@
ipc_rmid(&msg_ids(ns), &s->q_perm);
}
-static int newque (struct ipc_namespace *ns, key_t key, int msgflg)
+static int newque(struct ipc_namespace *ns, struct ipc_params *params)
{
struct msg_queue *msq;
int id, retval;
+ key_t key = params->key;
+ int msgflg = params->flg;
msq = ipc_rcu_alloc(sizeof(*msq));
if (!msq)
@@ -264,56 +266,27 @@
ipc_rcu_putref(msq);
}
+static inline int msg_security(void *msq, int msgflg)
+{
+ return security_msg_queue_associate((struct msg_queue *) msq, msgflg);
+}
+
asmlinkage long sys_msgget(key_t key, int msgflg)
{
- struct msg_queue *msq;
- int ret;
struct ipc_namespace *ns;
+ struct ipc_ops msg_ops;
+ struct ipc_params msg_params;
ns = current->nsproxy->ipc_ns;
- ret = idr_pre_get(&msg_ids(ns).ipcs_idr, GFP_KERNEL);
+ msg_ops.getnew = newque;
+ msg_ops.associate = msg_security;
+ msg_ops.more_checks = NULL;
- if (key == IPC_PRIVATE) {
- if (!ret)
- ret = -ENOMEM;
- else {
- mutex_lock(&msg_ids(ns).mutex);
- ret = newque(ns, key, msgflg);
- mutex_unlock(&msg_ids(ns).mutex);
- }
- } else {
- mutex_lock(&msg_ids(ns).mutex);
- msq = (struct msg_queue *) ipc_findkey(&msg_ids(ns), key);
- if (msq == NULL) {
- /* key not used */
- if (!(msgflg & IPC_CREAT))
- ret = -ENOENT;
- else if (!ret)
- ret = -ENOMEM;
- else
- ret = newque(ns, key, msgflg);
- } else {
- /* msq has been locked by ipc_findkey() */
+ msg_params.key = key;
+ msg_params.flg = msgflg;
- if (msgflg & IPC_CREAT && msgflg & IPC_EXCL)
- ret = -EEXIST;
- else {
- if (ipcperms(&msq->q_perm, msgflg))
- ret = -EACCES;
- else {
- ret = security_msg_queue_associate(
- msq, msgflg);
- if (!ret)
- ret = msq->q_perm.id;
- }
- }
- msg_unlock(msq);
- }
- mutex_unlock(&msg_ids(ns).mutex);
- }
-
- return ret;
+ return ipcget(ns, &msg_ids(ns), &msg_ops, &msg_params);
}
static inline unsigned long
diff --git a/ipc/sem.c b/ipc/sem.c
index f92a256..6af226a 100644
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -97,7 +97,7 @@
static struct ipc_ids init_sem_ids;
-static int newary(struct ipc_namespace *, key_t, int, int);
+static int newary(struct ipc_namespace *, struct ipc_params *);
static void freeary(struct ipc_namespace *, struct sem_array *);
#ifdef CONFIG_PROC_FS
static int sysvipc_sem_proc_show(struct seq_file *s, void *it);
@@ -214,12 +214,15 @@
*/
#define IN_WAKEUP 1
-static int newary (struct ipc_namespace *ns, key_t key, int nsems, int semflg)
+static int newary(struct ipc_namespace *ns, struct ipc_params *params)
{
int id;
int retval;
struct sem_array *sma;
int size;
+ key_t key = params->key;
+ int nsems = params->u.nsems;
+ int semflg = params->flg;
if (!nsems)
return -EINVAL;
@@ -263,61 +266,40 @@
return sma->sem_perm.id;
}
-asmlinkage long sys_semget (key_t key, int nsems, int semflg)
+
+static inline int sem_security(void *sma, int semflg)
{
- int err;
- struct sem_array *sma;
+ return security_sem_associate((struct sem_array *) sma, semflg);
+}
+
+static inline int sem_more_checks(void *sma, struct ipc_params *params)
+{
+ if (params->u.nsems > ((struct sem_array *)sma)->sem_nsems)
+ return -EINVAL;
+
+ return 0;
+}
+
+asmlinkage long sys_semget(key_t key, int nsems, int semflg)
+{
struct ipc_namespace *ns;
+ struct ipc_ops sem_ops;
+ struct ipc_params sem_params;
ns = current->nsproxy->ipc_ns;
if (nsems < 0 || nsems > ns->sc_semmsl)
return -EINVAL;
- err = idr_pre_get(&sem_ids(ns).ipcs_idr, GFP_KERNEL);
+ sem_ops.getnew = newary;
+ sem_ops.associate = sem_security;
+ sem_ops.more_checks = sem_more_checks;
- if (key == IPC_PRIVATE) {
- if (!err)
- err = -ENOMEM;
- else {
- mutex_lock(&sem_ids(ns).mutex);
- err = newary(ns, key, nsems, semflg);
- mutex_unlock(&sem_ids(ns).mutex);
- }
- } else {
- mutex_lock(&sem_ids(ns).mutex);
- sma = (struct sem_array *) ipc_findkey(&sem_ids(ns), key);
- if (sma == NULL) {
- /* key not used */
- if (!(semflg & IPC_CREAT))
- err = -ENOENT;
- else if (!err)
- err = -ENOMEM;
- else
- err = newary(ns, key, nsems, semflg);
- } else {
- /* sma has been locked by ipc_findkey() */
+ sem_params.key = key;
+ sem_params.flg = semflg;
+ sem_params.u.nsems = nsems;
- if (semflg & IPC_CREAT && semflg & IPC_EXCL)
- err = -EEXIST;
- else {
- if (nsems > sma->sem_nsems)
- err = -EINVAL;
- else if (ipcperms(&sma->sem_perm, semflg))
- err = -EACCES;
- else {
- err = security_sem_associate(sma,
- semflg);
- if (!err)
- err = sma->sem_perm.id;
- }
- }
- sem_unlock(sma);
- }
- mutex_unlock(&sem_ids(ns).mutex);
- }
-
- return err;
+ return ipcget(ns, &sem_ids(ns), &sem_ops, &sem_params);
}
/* Manage the doubly linked list sma->sem_pending as a FIFO:
diff --git a/ipc/shm.c b/ipc/shm.c
index dcc3332..d20cc25 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -68,8 +68,7 @@
#define shm_buildid(ns, id, seq) \
ipc_buildid(&shm_ids(ns), id, seq)
-static int newseg (struct ipc_namespace *ns, key_t key,
- int shmflg, size_t size);
+static int newseg(struct ipc_namespace *, struct ipc_params *);
static void shm_open(struct vm_area_struct *vma);
static void shm_close(struct vm_area_struct *vma);
static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp);
@@ -341,8 +340,11 @@
#endif
};
-static int newseg (struct ipc_namespace *ns, key_t key, int shmflg, size_t size)
+static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
{
+ key_t key = params->key;
+ int shmflg = params->flg;
+ size_t size = params->u.size;
int error;
struct shmid_kernel *shp;
int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
@@ -423,57 +425,36 @@
return error;
}
+static inline int shm_security(void *shp, int shmflg)
+{
+ return security_shm_associate((struct shmid_kernel *) shp, shmflg);
+}
+
+static inline int shm_more_checks(void *shp, struct ipc_params *params)
+{
+ if (((struct shmid_kernel *)shp)->shm_segsz < params->u.size)
+ return -EINVAL;
+
+ return 0;
+}
+
asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
{
- struct shmid_kernel *shp;
- int err;
struct ipc_namespace *ns;
+ struct ipc_ops shm_ops;
+ struct ipc_params shm_params;
ns = current->nsproxy->ipc_ns;
- err = idr_pre_get(&shm_ids(ns).ipcs_idr, GFP_KERNEL);
+ shm_ops.getnew = newseg;
+ shm_ops.associate = shm_security;
+ shm_ops.more_checks = shm_more_checks;
- if (key == IPC_PRIVATE) {
- if (!err)
- err = -ENOMEM;
- else {
- mutex_lock(&shm_ids(ns).mutex);
- err = newseg(ns, key, shmflg, size);
- mutex_unlock(&shm_ids(ns).mutex);
- }
- } else {
- mutex_lock(&shm_ids(ns).mutex);
- shp = (struct shmid_kernel *) ipc_findkey(&shm_ids(ns), key);
- if (shp == NULL) {
- if (!(shmflg & IPC_CREAT))
- err = -ENOENT;
- else if (!err)
- err = -ENOMEM;
- else
- err = newseg(ns, key, shmflg, size);
- } else {
- /* shp has been locked by ipc_findkey() */
+ shm_params.key = key;
+ shm_params.flg = shmflg;
+ shm_params.u.size = size;
- if ((shmflg & IPC_CREAT) && (shmflg & IPC_EXCL))
- err = -EEXIST;
- else {
- if (shp->shm_segsz < size)
- err = -EINVAL;
- else if (ipcperms(&shp->shm_perm, shmflg))
- err = -EACCES;
- else {
- err = security_shm_associate(shp,
- shmflg);
- if (!err)
- err = shp->shm_perm.id;
- }
- }
- shm_unlock(shp);
- }
- mutex_unlock(&shm_ids(ns).mutex);
- }
-
- return err;
+ return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
}
static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
diff --git a/ipc/util.c b/ipc/util.c
index 2a20587..03b8879 100644
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -197,7 +197,7 @@
* If key is found ipc contains its ipc structure
*/
-struct kern_ipc_perm *ipc_findkey(struct ipc_ids *ids, key_t key)
+static struct kern_ipc_perm *ipc_findkey(struct ipc_ids *ids, key_t key)
{
struct kern_ipc_perm *ipc;
int next_id;
@@ -301,6 +301,105 @@
}
/**
+ * ipcget_new - create a new ipc object
+ * @ns: namespace
+ * @ids: identifer set
+ * @ops: the actual creation routine to call
+ * @params: its parameters
+ *
+ * This routine is called sys_msgget, sys_semget() and sys_shmget() when
+ * the key is IPC_PRIVATE
+ */
+int ipcget_new(struct ipc_namespace *ns, struct ipc_ids *ids,
+ struct ipc_ops *ops, struct ipc_params *params)
+{
+ int err;
+
+ err = idr_pre_get(&ids->ipcs_idr, GFP_KERNEL);
+
+ if (!err)
+ return -ENOMEM;
+
+ mutex_lock(&ids->mutex);
+ err = ops->getnew(ns, params);
+ mutex_unlock(&ids->mutex);
+
+ return err;
+}
+
+/**
+ * ipc_check_perms - check security and permissions for an IPC
+ * @ipcp: ipc permission set
+ * @ids: identifer set
+ * @ops: the actual security routine to call
+ * @params: its parameters
+ */
+static int ipc_check_perms(struct kern_ipc_perm *ipcp, struct ipc_ops *ops,
+ struct ipc_params *params)
+{
+ int err;
+
+ if (ipcperms(ipcp, params->flg))
+ err = -EACCES;
+ else {
+ err = ops->associate(ipcp, params->flg);
+ if (!err)
+ err = ipcp->id;
+ }
+
+ return err;
+}
+
+/**
+ * ipcget_public - get an ipc object or create a new one
+ * @ns: namespace
+ * @ids: identifer set
+ * @ops: the actual creation routine to call
+ * @params: its parameters
+ *
+ * This routine is called sys_msgget, sys_semget() and sys_shmget() when
+ * the key is not IPC_PRIVATE
+ */
+int ipcget_public(struct ipc_namespace *ns, struct ipc_ids *ids,
+ struct ipc_ops *ops, struct ipc_params *params)
+{
+ struct kern_ipc_perm *ipcp;
+ int flg = params->flg;
+ int err;
+
+ err = idr_pre_get(&ids->ipcs_idr, GFP_KERNEL);
+
+ mutex_lock(&ids->mutex);
+ ipcp = ipc_findkey(ids, params->key);
+ if (ipcp == NULL) {
+ /* key not used */
+ if (!(flg & IPC_CREAT))
+ err = -ENOENT;
+ else if (!err)
+ err = -ENOMEM;
+ else
+ err = ops->getnew(ns, params);
+ } else {
+ /* ipc object has been locked by ipc_findkey() */
+
+ if (flg & IPC_CREAT && flg & IPC_EXCL)
+ err = -EEXIST;
+ else {
+ err = 0;
+ if (ops->more_checks)
+ err = ops->more_checks(ipcp, params);
+ if (!err)
+ err = ipc_check_perms(ipcp, ops, params);
+ }
+ ipc_unlock(ipcp);
+ }
+ mutex_unlock(&ids->mutex);
+
+ return err;
+}
+
+
+/**
* ipc_rmid - remove an IPC identifier
* @ids: identifier set
* @id: ipc perm structure containing the identifier to remove
diff --git a/ipc/util.h b/ipc/util.h
index c906326..30b2a6d 100644
--- a/ipc/util.h
+++ b/ipc/util.h
@@ -35,6 +35,35 @@
struct idr ipcs_idr;
};
+/*
+ * Structure that holds the parameters needed by the ipc operations
+ * (see after)
+ */
+struct ipc_params {
+ key_t key;
+ int flg;
+ union {
+ size_t size; /* for shared memories */
+ int nsems; /* for semaphores */
+ } u; /* holds the getnew() specific param */
+};
+
+/*
+ * Structure that holds some ipc operations. This structure is used to unify
+ * the calls to sys_msgget(), sys_semget(), sys_shmget()
+ * . routine to call to create a new ipc object. Can be one of newque,
+ * newary, newseg
+ * . routine to call to call to check permissions for a new ipc object.
+ * Can be one of security_msg_associate, security_sem_associate,
+ * security_shm_associate
+ * . routine to call for an extra check if needed
+ */
+struct ipc_ops {
+ int (*getnew) (struct ipc_namespace *, struct ipc_params *);
+ int (*associate) (void *, int);
+ int (*more_checks) (void *, struct ipc_params *);
+};
+
struct seq_file;
void ipc_init_ids(struct ipc_ids *);
@@ -50,7 +79,6 @@
#define IPC_SHM_IDS 2
/* must be called with ids->mutex acquired.*/
-struct kern_ipc_perm *ipc_findkey(struct ipc_ids *ids, key_t key);
int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int);
int ipc_get_maxid(struct ipc_ids *);
@@ -95,5 +123,18 @@
extern void free_msg(struct msg_msg *msg);
extern struct msg_msg *load_msg(const void __user *src, int len);
extern int store_msg(void __user *dest, struct msg_msg *msg, int len);
+extern int ipcget_new(struct ipc_namespace *, struct ipc_ids *,
+ struct ipc_ops *, struct ipc_params *);
+extern int ipcget_public(struct ipc_namespace *, struct ipc_ids *,
+ struct ipc_ops *, struct ipc_params *);
+
+static inline int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
+ struct ipc_ops *ops, struct ipc_params *params)
+{
+ if (params->key == IPC_PRIVATE)
+ return ipcget_new(ns, ids, ops, params);
+ else
+ return ipcget_public(ns, ids, ops, params);
+}
#endif