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>

1 files changed, 100 insertions, 1 deletions

diff --git a/ipc/util.c b/ipc/util.c
index 2a205875d277..03b88798f71f 100644
--- 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
  */
  
-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 @@ 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