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authorSerge E. Hallyn <serue@us.ibm.com>2006-10-02 02:18:14 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-10-02 07:57:21 -0700
commit4865ecf1315b450ab3317a745a6678c04d311e40 (patch)
tree6cf5d3028f8642eba2a8094eb413db080cc9219c
parent[PATCH] namespaces: utsname: use init_utsname when appropriate (diff)
downloadlinux-dev-4865ecf1315b450ab3317a745a6678c04d311e40.tar.xz
linux-dev-4865ecf1315b450ab3317a745a6678c04d311e40.zip
[PATCH] namespaces: utsname: implement utsname namespaces
This patch defines the uts namespace and some manipulators. Adds the uts namespace to task_struct, and initializes a system-wide init namespace. It leaves a #define for system_utsname so sysctl will compile. This define will be removed in a separate patch. [akpm@osdl.org: build fix, cleanup] Signed-off-by: Serge Hallyn <serue@us.ibm.com> Cc: Kirill Korotaev <dev@openvz.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Andrey Savochkin <saw@sw.ru> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--include/linux/init_task.h2
-rw-r--r--include/linux/nsproxy.h2
-rw-r--r--include/linux/sched.h1
-rw-r--r--include/linux/utsname.h40
-rw-r--r--init/Kconfig8
-rw-r--r--init/version.c23
-rw-r--r--kernel/Makefile1
-rw-r--r--kernel/nsproxy.c14
-rw-r--r--kernel/utsname.c42
9 files changed, 121 insertions, 12 deletions
diff --git a/include/linux/init_task.h b/include/linux/init_task.h
index 4865348ca8bd..e08531ec32f0 100644
--- a/include/linux/init_task.h
+++ b/include/linux/init_task.h
@@ -4,6 +4,7 @@
#include <linux/file.h>
#include <linux/rcupdate.h>
#include <linux/irqflags.h>
+#include <linux/utsname.h>
#include <linux/lockdep.h>
#define INIT_FDTABLE \
@@ -72,6 +73,7 @@ extern struct nsproxy init_nsproxy;
#define INIT_NSPROXY(nsproxy) { \
.count = ATOMIC_INIT(1), \
.nslock = SPIN_LOCK_UNLOCKED, \
+ .uts_ns = &init_uts_ns, \
.namespace = NULL, \
}
diff --git a/include/linux/nsproxy.h b/include/linux/nsproxy.h
index 7ebe66670c59..9c2e0ad508db 100644
--- a/include/linux/nsproxy.h
+++ b/include/linux/nsproxy.h
@@ -5,6 +5,7 @@
#include <linux/sched.h>
struct namespace;
+struct uts_namespace;
/*
* A structure to contain pointers to all per-process
@@ -21,6 +22,7 @@ struct namespace;
struct nsproxy {
atomic_t count;
spinlock_t nslock;
+ struct uts_namespace *uts_ns;
struct namespace *namespace;
};
extern struct nsproxy init_nsproxy;
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 670b89a20070..46d6f5be72f2 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -753,6 +753,7 @@ static inline void prefetch_stack(struct task_struct *t) { }
struct audit_context; /* See audit.c */
struct mempolicy;
struct pipe_inode_info;
+struct uts_namespace;
enum sleep_type {
SLEEP_NORMAL,
diff --git a/include/linux/utsname.h b/include/linux/utsname.h
index 77e97a5755d9..afa54e1542b3 100644
--- a/include/linux/utsname.h
+++ b/include/linux/utsname.h
@@ -1,6 +1,11 @@
#ifndef _LINUX_UTSNAME_H
#define _LINUX_UTSNAME_H
+#include <linux/sched.h>
+#include <linux/kref.h>
+#include <linux/nsproxy.h>
+#include <asm/atomic.h>
+
#define __OLD_UTS_LEN 8
struct oldold_utsname {
@@ -30,17 +35,46 @@ struct new_utsname {
char domainname[65];
};
-extern struct new_utsname system_utsname;
+struct uts_namespace {
+ struct kref kref;
+ struct new_utsname name;
+};
+extern struct uts_namespace init_uts_ns;
+
+static inline void get_uts_ns(struct uts_namespace *ns)
+{
+ kref_get(&ns->kref);
+}
+
+#ifdef CONFIG_UTS_NS
+extern int copy_utsname(int flags, struct task_struct *tsk);
+extern void free_uts_ns(struct kref *kref);
+
+static inline void put_uts_ns(struct uts_namespace *ns)
+{
+ kref_put(&ns->kref, free_uts_ns);
+}
+#else
+static inline int copy_utsname(int flags, struct task_struct *tsk)
+{
+ return 0;
+}
+static inline void put_uts_ns(struct uts_namespace *ns)
+{
+}
+#endif
static inline struct new_utsname *utsname(void)
{
- return &system_utsname;
+ return &current->nsproxy->uts_ns->name;
}
static inline struct new_utsname *init_utsname(void)
{
- return &system_utsname;
+ return &init_uts_ns.name;
}
+#define system_utsname init_uts_ns.name
+
extern struct rw_semaphore uts_sem;
#endif
diff --git a/init/Kconfig b/init/Kconfig
index f7a04d0daf07..b0ea97554473 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -182,6 +182,14 @@ config TASK_DELAY_ACCT
Say N if unsure.
+config UTS_NS
+ bool "UTS Namespaces"
+ default n
+ help
+ Support uts namespaces. This allows containers, i.e.
+ vservers, to use uts namespaces to provide different
+ uts info for different servers. If unsure, say N.
+
config AUDIT
bool "Auditing support"
depends on NET
diff --git a/init/version.c b/init/version.c
index e290802c6bd2..8f28344d9c70 100644
--- a/init/version.c
+++ b/init/version.c
@@ -12,22 +12,27 @@
#include <linux/utsname.h>
#include <linux/utsrelease.h>
#include <linux/version.h>
+#include <linux/sched.h>
#define version(a) Version_ ## a
#define version_string(a) version(a)
int version_string(LINUX_VERSION_CODE);
-struct new_utsname system_utsname = {
- .sysname = UTS_SYSNAME,
- .nodename = UTS_NODENAME,
- .release = UTS_RELEASE,
- .version = UTS_VERSION,
- .machine = UTS_MACHINE,
- .domainname = UTS_DOMAINNAME,
+struct uts_namespace init_uts_ns = {
+ .kref = {
+ .refcount = ATOMIC_INIT(2),
+ },
+ .name = {
+ .sysname = UTS_SYSNAME,
+ .nodename = UTS_NODENAME,
+ .release = UTS_RELEASE,
+ .version = UTS_VERSION,
+ .machine = UTS_MACHINE,
+ .domainname = UTS_DOMAINNAME,
+ },
};
-
-EXPORT_SYMBOL(system_utsname);
+EXPORT_SYMBOL_GPL(init_uts_ns);
const char linux_banner[] =
"Linux version " UTS_RELEASE " (" LINUX_COMPILE_BY "@"
diff --git a/kernel/Makefile b/kernel/Makefile
index 6ec53009b866..d948ca12acf0 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -48,6 +48,7 @@ obj-$(CONFIG_GENERIC_HARDIRQS) += irq/
obj-$(CONFIG_SECCOMP) += seccomp.o
obj-$(CONFIG_RCU_TORTURE_TEST) += rcutorture.o
obj-$(CONFIG_RELAY) += relay.o
+obj-$(CONFIG_UTS_NS) += utsname.o
obj-$(CONFIG_TASK_DELAY_ACCT) += delayacct.o
obj-$(CONFIG_TASKSTATS) += taskstats.o tsacct.o
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index e10385c17f73..47c19280c55b 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -14,6 +14,7 @@
#include <linux/nsproxy.h>
#include <linux/init_task.h>
#include <linux/namespace.h>
+#include <linux/utsname.h>
struct nsproxy init_nsproxy = INIT_NSPROXY(init_nsproxy);
@@ -59,6 +60,8 @@ struct nsproxy *dup_namespaces(struct nsproxy *orig)
if (ns) {
if (ns->namespace)
get_namespace(ns->namespace);
+ if (ns->uts_ns)
+ get_uts_ns(ns->uts_ns);
}
return ns;
@@ -97,6 +100,15 @@ int copy_namespaces(int flags, struct task_struct *tsk)
goto out;
}
+ err = copy_utsname(flags, tsk);
+ if (err) {
+ if (new_ns->namespace)
+ put_namespace(new_ns->namespace);
+ tsk->nsproxy = old_ns;
+ put_nsproxy(new_ns);
+ goto out;
+ }
+
out:
put_nsproxy(old_ns);
return err;
@@ -106,5 +118,7 @@ void free_nsproxy(struct nsproxy *ns)
{
if (ns->namespace)
put_namespace(ns->namespace);
+ if (ns->uts_ns)
+ put_uts_ns(ns->uts_ns);
kfree(ns);
}
diff --git a/kernel/utsname.c b/kernel/utsname.c
new file mode 100644
index 000000000000..1824384ecfa3
--- /dev/null
+++ b/kernel/utsname.c
@@ -0,0 +1,42 @@
+/*
+ * Copyright (C) 2004 IBM Corporation
+ *
+ * Author: Serge Hallyn <serue@us.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation, version 2 of the
+ * License.
+ */
+
+#include <linux/module.h>
+#include <linux/uts.h>
+#include <linux/utsname.h>
+#include <linux/version.h>
+
+/*
+ * Copy task tsk's utsname namespace, or clone it if flags
+ * specifies CLONE_NEWUTS. In latter case, changes to the
+ * utsname of this process won't be seen by parent, and vice
+ * versa.
+ */
+int copy_utsname(int flags, struct task_struct *tsk)
+{
+ struct uts_namespace *old_ns = tsk->nsproxy->uts_ns;
+ int err = 0;
+
+ if (!old_ns)
+ return 0;
+
+ get_uts_ns(old_ns);
+
+ return err;
+}
+
+void free_uts_ns(struct kref *kref)
+{
+ struct uts_namespace *ns;
+
+ ns = container_of(kref, struct uts_namespace, kref);
+ kfree(ns);
+}