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 (file)
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -81,7 +81,7 @@ static struct ipc_ids init_msg_ids;
        ipc_buildid(&msg_ids(ns), id, seq)
 
 static void freeque(struct ipc_namespace *, struct msg_queue *);
        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
 #ifdef CONFIG_PROC_FS
 static int sysvipc_msg_proc_show(struct seq_file *s, void *it);
 #endif


@@ -144,10 +144,12 @@ static inline void msg_rmid(struct ipc_namespace *ns, struct msg_queue *s)
        ipc_rmid(&msg_ids(ns), &s->q_perm);
 }
 
        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;
 {
        struct msg_queue *msq;
        int id, retval;

+       key_t key = params->key;
+       int msgflg = params->flg;

 
        msq = ipc_rcu_alloc(sizeof(*msq));
        if (!msq)
 
        msq = ipc_rcu_alloc(sizeof(*msq));
        if (!msq)


@@ -264,56 +266,27 @@ static void freeque(struct ipc_namespace *ns, struct msg_queue *msq)
        ipc_rcu_putref(msq);
 }
 
        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)
 {
 asmlinkage long sys_msgget(key_t key, int msgflg)
 {

-       struct msg_queue *msq;
-       int ret;

        struct ipc_namespace *ns;
        struct ipc_namespace *ns;

+       struct ipc_ops msg_ops;
+       struct ipc_params msg_params;

 
        ns = current->nsproxy->ipc_ns;
 
 
        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() */
-
-                       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);
-       }
+       msg_params.key = key;
+       msg_params.flg = msgflg;

 
 

-       return ret;
+       return ipcget(ns, &msg_ids(ns), &msg_ops, &msg_params);

 }
 
 static inline unsigned long
 }
 
 static inline unsigned long

diff --git a/ipc/sem.c b/ipc/sem.c
index f92a256..6af226a 100644 (file)
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -97,7 +97,7 @@
 
 static struct ipc_ids init_sem_ids;
 
 
 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);
 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 @@ static inline void sem_rmid(struct ipc_namespace *ns, struct sem_array *s)
  */
 #define IN_WAKEUP      1
 
  */
 #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;
 {
        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;
 
        if (!nsems)
                return -EINVAL;


@@ -263,61 +266,40 @@ static int newary (struct ipc_namespace *ns, key_t key, int nsems, int semflg)
        return sma->sem_perm.id;
 }
 
        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)
+{
+       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)

 {
 {

-       int err;
-       struct sem_array *sma;

        struct ipc_namespace *ns;
        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;
 
 
        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() */
-
-                       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);
-       }
+       sem_params.key = key;
+       sem_params.flg = semflg;
+       sem_params.u.nsems = nsems;

 
 

-       return err;
+       return ipcget(ns, &sem_ids(ns), &sem_ops, &sem_params);

 }
 
 /* Manage the doubly linked list sma->sem_pending as a FIFO:
 }
 
 /* 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 (file)
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -68,8 +68,7 @@ static struct ipc_ids init_shm_ids;
 #define shm_buildid(ns, id, seq)       \
        ipc_buildid(&shm_ids(ns), id, seq)
 
 #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);
 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 @@ static struct vm_operations_struct shm_vm_ops = {
 #endif
 };
 
 #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;
        int error;
        struct shmid_kernel *shp;
        int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;


@@ -423,57 +425,36 @@ no_file:
        return error;
 }
 
        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)
 {
 asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
 {

-       struct shmid_kernel *shp;
-       int err;

        struct ipc_namespace *ns;
        struct ipc_namespace *ns;

+       struct ipc_ops shm_ops;
+       struct ipc_params shm_params;

 
        ns = current->nsproxy->ipc_ns;
 
 
        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() */
-
-                       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);
-       }
+       shm_params.key = key;
+       shm_params.flg = shmflg;
+       shm_params.u.size = size;

 
 

-       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)
 }
 
 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 (file)
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -197,7 +197,7 @@ void __init ipc_init_proc_interface(const char *path, const char *header,
  *     If key is found ipc contains its ipc structure
  */
  
  *     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;
 {
        struct kern_ipc_perm *ipc;
        int next_id;


@@ -301,6 +301,105 @@ int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size)
 }
 
 /**
 }
 
 /**

+ *     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
  *     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 (file)
--- a/ipc/util.h
+++ b/ipc/util.h
@@ -35,6 +35,35 @@ struct ipc_ids {
        struct idr ipcs_idr;
 };
 
        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 *);
 struct seq_file;
 
 void ipc_init_ids(struct ipc_ids *);


@@ -50,7 +79,6 @@ void __init ipc_init_proc_interface(const char *path, const char *header,
 #define IPC_SHM_IDS    2
 
 /* must be called with ids->mutex acquired.*/
 #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 *);
 
 int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int);
 int ipc_get_maxid(struct ipc_ids *);
 


@@ -95,5 +123,18 @@ int ipc_parse_version (int *cmd);
 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 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
 
 #endif