[PATCH] IPC namespace - utils

This patch adds basic IPC namespace functionality to
IPC utils:
- init_ipc_ns
- copy/clone/unshare/free IPC ns
- /proc preparations

Signed-off-by: Pavel Emelianov <xemul@openvz.org>
Signed-off-by: Kirill Korotaev <dev@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 143 insertions, 13 deletions

diff --git a/ipc/util.c b/ipc/util.c
index 67b6d178db6e..42479e4eec59 100644
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -12,6 +12,9 @@
  *            Mingming Cao <cmm@us.ibm.com>
  * Mar 2006 - support for audit of ipc object properties
  *            Dustin Kirkland <dustin.kirkland@us.ibm.com>
+ * Jun 2006 - namespaces ssupport
+ *            OpenVZ, SWsoft Inc.
+ *            Pavel Emelianov <xemul@openvz.org>
  */
 
 #include <linux/mm.h>
@@ -29,6 +32,7 @@
 #include <linux/seq_file.h>
 #include <linux/proc_fs.h>
 #include <linux/audit.h>
+#include <linux/nsproxy.h>
 
 #include <asm/unistd.h>
 
@@ -37,10 +41,111 @@
 struct ipc_proc_iface {
         const char *path;
         const char *header;
-        struct ipc_ids *ids;
+        int ids;
         int (*show)(struct seq_file *, void *);
 };
 
+struct ipc_namespace init_ipc_ns = {
+        .kref = {
+                .refcount       = ATOMIC_INIT(2),
+        },
+};
+
+#ifdef CONFIG_IPC_NS
+static struct ipc_namespace *clone_ipc_ns(struct ipc_namespace *old_ns)
+{
+        int err;
+        struct ipc_namespace *ns;
+
+        err = -ENOMEM;
+        ns = kmalloc(sizeof(struct ipc_namespace), GFP_KERNEL);
+        if (ns == NULL)
+                goto err_mem;
+
+        err = sem_init_ns(ns);
+        if (err)
+                goto err_sem;
+        err = msg_init_ns(ns);
+        if (err)
+                goto err_msg;
+        err = shm_init_ns(ns);
+        if (err)
+                goto err_shm;
+
+        kref_init(&ns->kref);
+        return ns;
+
+err_shm:
+        msg_exit_ns(ns);
+err_msg:
+        sem_exit_ns(ns);
+err_sem:
+        kfree(ns);
+err_mem:
+        return ERR_PTR(err);
+}
+
+int unshare_ipcs(unsigned long unshare_flags, struct ipc_namespace **new_ipc)
+{
+        struct ipc_namespace *new;
+
+        if (unshare_flags & CLONE_NEWIPC) {
+                if (!capable(CAP_SYS_ADMIN))
+                        return -EPERM;
+
+                new = clone_ipc_ns(current->nsproxy->ipc_ns);
+                if (IS_ERR(new))
+                        return PTR_ERR(new);
+
+                *new_ipc = new;
+        }
+
+        return 0;
+}
+
+int copy_ipcs(unsigned long flags, struct task_struct *tsk)
+{
+        struct ipc_namespace *old_ns = tsk->nsproxy->ipc_ns;
+        struct ipc_namespace *new_ns;
+        int err = 0;
+
+        if (!old_ns)
+                return 0;
+
+        get_ipc_ns(old_ns);
+
+        if (!(flags & CLONE_NEWIPC))
+                return 0;
+
+        if (!capable(CAP_SYS_ADMIN)) {
+                err = -EPERM;
+                goto out;
+        }
+
+        new_ns = clone_ipc_ns(old_ns);
+        if (!new_ns) {
+                err = -ENOMEM;
+                goto out;
+        }
+
+        tsk->nsproxy->ipc_ns = new_ns;
+out:
+        put_ipc_ns(old_ns);
+        return err;
+}
+
+void free_ipc_ns(struct kref *kref)
+{
+        struct ipc_namespace *ns;
+
+        ns = container_of(kref, struct ipc_namespace, kref);
+        sem_exit_ns(ns);
+        msg_exit_ns(ns);
+        shm_exit_ns(ns);
+        kfree(ns);
+}
+#endif
+
 /**
  *      ipc_init        -       initialise IPC subsystem
  *
@@ -67,7 +172,7 @@ __initcall(ipc_init);
  *      array itself. 
  */
  
-void __init ipc_init_ids(struct ipc_ids* ids, int size)
+void __ipc_init ipc_init_ids(struct ipc_ids* ids, int size)
 {
         int i;
 
@@ -110,8 +215,7 @@ static struct file_operations sysvipc_proc_fops;
  *      @show: show routine.
  */
 void __init ipc_init_proc_interface(const char *path, const char *header,
-                                    struct ipc_ids *ids,
-                                    int (*show)(struct seq_file *, void *))
+                int ids, int (*show)(struct seq_file *, void *))
 {
         struct proc_dir_entry *pde;
         struct ipc_proc_iface *iface;
@@ -635,6 +739,9 @@ static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos)
         struct ipc_proc_iface *iface = s->private;
         struct kern_ipc_perm *ipc = it;
         loff_t p;
+        struct ipc_ids *ids;
+
+        ids = current->nsproxy->ipc_ns->ids[iface->ids];
 
         /* If we had an ipc id locked before, unlock it */
         if (ipc && ipc != SEQ_START_TOKEN)
@@ -644,8 +751,8 @@ static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos)
          * p = *pos - 1 (because id 0 starts at position 1)
          *          + 1 (because we increment the position by one)
          */
-        for (p = *pos; p <= iface->ids->max_id; p++) {
-                if ((ipc = ipc_lock(iface->ids, p)) != NULL) {
+        for (p = *pos; p <= ids->max_id; p++) {
+                if ((ipc = ipc_lock(ids, p)) != NULL) {
                         *pos = p + 1;
                         return ipc;
                 }
@@ -664,12 +771,15 @@ static void *sysvipc_proc_start(struct seq_file *s, loff_t *pos)
         struct ipc_proc_iface *iface = s->private;
         struct kern_ipc_perm *ipc;
         loff_t p;
+        struct ipc_ids *ids;
+
+        ids = current->nsproxy->ipc_ns->ids[iface->ids];
 
         /*
          * Take the lock - this will be released by the corresponding
          * call to stop().
          */
-        mutex_lock(&iface->ids->mutex);
+        mutex_lock(&ids->mutex);
 
         /* pos < 0 is invalid */
         if (*pos < 0)
@@ -680,8 +790,8 @@ static void *sysvipc_proc_start(struct seq_file *s, loff_t *pos)
                 return SEQ_START_TOKEN;
 
         /* Find the (pos-1)th ipc */
-        for (p = *pos - 1; p <= iface->ids->max_id; p++) {
-                if ((ipc = ipc_lock(iface->ids, p)) != NULL) {
+        for (p = *pos - 1; p <= ids->max_id; p++) {
+                if ((ipc = ipc_lock(ids, p)) != NULL) {
                         *pos = p + 1;
                         return ipc;
                 }
@@ -693,13 +803,15 @@ static void sysvipc_proc_stop(struct seq_file *s, void *it)
 {
         struct kern_ipc_perm *ipc = it;
         struct ipc_proc_iface *iface = s->private;
+        struct ipc_ids *ids;
 
         /* If we had a locked segment, release it */
         if (ipc && ipc != SEQ_START_TOKEN)
                 ipc_unlock(ipc);
 
+        ids = current->nsproxy->ipc_ns->ids[iface->ids];
         /* Release the lock we took in start() */
-        mutex_unlock(&iface->ids->mutex);
+        mutex_unlock(&ids->mutex);
 }
 
 static int sysvipc_proc_show(struct seq_file *s, void *it)
diff --git a/ipc/util.h b/ipc/util.h
index 0181553d31d8..c8fd6b9d77b5 100644
--- a/ipc/util.h
+++ b/ipc/util.h
@@ -3,6 +3,8 @@
  * Copyright (C) 1999 Christoph Rohland
  *
  * ipc helper functions (c) 1999 Manfred Spraul <manfred@colorfullife.com>
+ * namespaces support.      2006 OpenVZ, SWsoft Inc.
+ *                               Pavel Emelianov <xemul@openvz.org>
  */
 
 #ifndef _IPC_UTIL_H
@@ -15,6 +17,14 @@ void sem_init (void);
 void msg_init (void);
 void shm_init (void);
 
+int sem_init_ns(struct ipc_namespace *ns);
+int msg_init_ns(struct ipc_namespace *ns);
+int shm_init_ns(struct ipc_namespace *ns);
+
+void sem_exit_ns(struct ipc_namespace *ns);
+void msg_exit_ns(struct ipc_namespace *ns);
+void shm_exit_ns(struct ipc_namespace *ns);
+
 struct ipc_id_ary {
         int size;
         struct kern_ipc_perm *p[0];
@@ -31,15 +41,23 @@ struct ipc_ids {
 };
 
 struct seq_file;
-void __init ipc_init_ids(struct ipc_ids* ids, int size);
+#ifdef CONFIG_IPC_NS
+#define __ipc_init
+#else
+#define __ipc_init      __init
+#endif
+void __ipc_init ipc_init_ids(struct ipc_ids *ids, int size);
 #ifdef CONFIG_PROC_FS
 void __init ipc_init_proc_interface(const char *path, const char *header,
-                                    struct ipc_ids *ids,
-                                    int (*show)(struct seq_file *, void *));
+                int ids, int (*show)(struct seq_file *, void *));
 #else
 #define ipc_init_proc_interface(path, header, ids, show) do {} while (0)
 #endif
 
+#define IPC_SEM_IDS     0
+#define IPC_MSG_IDS     1
+#define IPC_SHM_IDS     2
+
 /* must be called with ids->mutex acquired.*/
 int ipc_findkey(struct ipc_ids* ids, key_t key);
 int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size);