[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>

diff --git a/include/linux/init_task.h b/include/linux/init_task.h
index ceecf69..33c5daa 100644 (file)
--- a/include/linux/init_task.h
+++ b/include/linux/init_task.h
@@ -6,6 +6,7 @@
 #include <linux/irqflags.h>
 #include <linux/utsname.h>
 #include <linux/lockdep.h>
+#include <linux/ipc.h>
 
 #define INIT_FDTABLE \
 {                                                      \
@@ -74,8 +75,8 @@ extern struct nsproxy init_nsproxy;
        .count          = ATOMIC_INIT(1),                               \
        .nslock         = SPIN_LOCK_UNLOCKED,                           \
        .uts_ns         = &init_uts_ns,                                 \
-       .ipc_ns         = &init_ipc_ns,                                 \
        .namespace      = NULL,                                         \
+       INIT_IPC_NS(ipc_ns)                                             \
 }
 
 #define INIT_SIGHAND(sighand) {                                                \

diff --git a/include/linux/ipc.h b/include/linux/ipc.h
index 36027b1..d9e2b3f 100644 (file)
--- a/include/linux/ipc.h
+++ b/include/linux/ipc.h
@@ -88,20 +88,38 @@ struct ipc_namespace {
 };
 
 extern struct ipc_namespace init_ipc_ns;
+
+#ifdef CONFIG_SYSVIPC
+#define INIT_IPC_NS(ns)                .ns             = &init_ipc_ns,
+#else
+#define INIT_IPC_NS(ns)
+#endif
+
+#ifdef CONFIG_IPC_NS
 extern void free_ipc_ns(struct kref *kref);
 extern int copy_ipcs(unsigned long flags, struct task_struct *tsk);
 extern int unshare_ipcs(unsigned long flags, struct ipc_namespace **ns);
+#else
+static inline int copy_ipcs(unsigned long flags, struct task_struct *tsk)
+{
+       return 0;
+}
+#endif
 
 static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
 {
+#ifdef CONFIG_IPC_NS
        if (ns)
                kref_get(&ns->kref);
+#endif
        return ns;
 }
 
 static inline void put_ipc_ns(struct ipc_namespace *ns)
 {
+#ifdef CONFIG_IPC_NS
        kref_put(&ns->kref, free_ipc_ns);
+#endif
 }
 
 #endif /* __KERNEL__ */

diff --git a/ipc/util.c b/ipc/util.c
index 67b6d17..42479e4 100644 (file)
--- 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 0181553..c8fd6b9 100644 (file)
--- 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);

diff --git a/kernel/fork.c b/kernel/fork.c
index d6cc565..7dc6140 100644 (file)
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1589,6 +1589,16 @@ static int unshare_semundo(unsigned long unshare_flags, struct sem_undo_list **n
        return 0;
 }
 
+#ifndef CONFIG_IPC_NS
+static inline int unshare_ipcs(unsigned long flags, struct ipc_namespace **ns)
+{
+       if (flags & CLONE_NEWIPC)
+               return -EINVAL;
+
+       return 0;
+}
+#endif
+
 /*
  * unshare allows a process to 'unshare' part of the process
  * context which was originally shared using clone.  copy_*