OpenVZ Forum


Home » Mailing lists » Devel » [RFC][PATCH 0/5] uts namespaces: Introduction
[RFC][PATCH 1/5] uts namespaces: Implement utsname namespaces [message #2485 is a reply to message #2484] Fri, 07 April 2006 18:36 Go to previous messageGo to previous message
serue is currently offline  serue
Messages: 750
Registered: February 2006
Senior Member
This patch defines the uts namespace and some manipulators.
Adds the uts namespace to task_struct, and initializes a
system-wide init namespace which will continue to be used when
it makes sense.

Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
---
include/linux/init_task.h | 2 +
include/linux/sched.h | 2 +
include/linux/utsname.h | 40 +++++++++++++++++++++++++-
init/Kconfig | 8 +++++
init/version.c | 70 ++++++++++++++++++++++++++++++++++++++++-----
kernel/exit.c | 2 +
kernel/fork.c | 9 +++++-
7 files changed, 122 insertions(+), 11 deletions(-)

14c326d603d88d9ed40a1ddafbf23fc3da68a645
diff --git a/include/linux/init_task.h b/include/linux/init_task.h
index 41ecbb8..21b1751 100644
--- a/include/linux/init_task.h
+++ b/include/linux/init_task.h
@@ -3,6 +3,7 @@

#include <linux/file.h>
#include <linux/rcupdate.h>
+#include <linux/utsname.h>

#define INIT_FDTABLE \
{ \
@@ -123,6 +124,7 @@ extern struct group_info init_groups;
.journal_info = NULL, \
.cpu_timers = INIT_CPU_TIMERS(tsk.cpu_timers), \
.fs_excl = ATOMIC_INIT(0), \
+ .uts_ns = &init_uts_ns, \
}


diff --git a/include/linux/sched.h b/include/linux/sched.h
index 541f482..97c7990 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -684,6 +684,7 @@ static inline void prefetch_stack(struct

struct audit_context; /* See audit.c */
struct mempolicy;
+struct uts_namespace;

enum sleep_type {
SLEEP_NORMAL,
@@ -807,6 +808,7 @@ struct task_struct {
struct files_struct *files;
/* namespace */
struct namespace *namespace;
+ struct uts_namespace *uts_ns;
/* signal handlers */
struct signal_struct *signal;
struct sighand_struct *sighand;
diff --git a/include/linux/utsname.h b/include/linux/utsname.h
index 13e1da0..cc28ac5 100644
--- a/include/linux/utsname.h
+++ b/include/linux/utsname.h
@@ -1,5 +1,8 @@
#ifndef _LINUX_UTSNAME_H
#define _LINUX_UTSNAME_H
+#include <linux/sched.h>
+#include <linux/kref.h>
+#include <asm/atomic.h>

#define __OLD_UTS_LEN 8

@@ -30,7 +33,42 @@ 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;
+
+#ifdef CONFIG_UTS_NS
+
+extern struct uts_namespace *clone_uts_ns(struct uts_namespace *old_ns);
+extern struct uts_namespace *unshare_uts_ns(void);
+extern void free_uts_ns(struct kref *kref);
+
+static inline void get_uts_ns(struct uts_namespace *ns)
+{
+ kref_get(&ns->kref);
+}
+
+static inline void put_uts_ns(struct uts_namespace *ns)
+{
+ kref_put(&ns->kref, free_uts_ns);
+}
+
+#else
+static inline void get_uts_ns(struct uts_namespace *ns)
+{
+}
+static inline void put_uts_ns(struct uts_namespace *ns)
+{
+}
+#endif
+
+static inline struct new_utsname *utsname(void)
+{
+ return &current->uts_ns->name;
+}
+

extern struct rw_semaphore uts_sem;
#endif
diff --git a/init/Kconfig b/init/Kconfig
index 3b36a1d..8460e5a 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -166,6 +166,14 @@ config SYSCTL
building a kernel for install/rescue disks or your system is very
limited in memory.

+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 3ddc3ce..e128d72 100644
--- a/init/version.c
+++ b/init/version.c
@@ -11,22 +11,76 @@
#include <linux/uts.h>
#include <linux/utsname.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);
+#ifdef CONFIG_UTS_NS
+/*
+ * Clone a new ns copying an original utsname, setting refcount to 1
+ * @old_ns: namespace to clone
+ * Return NULL on error (failure to kmalloc), new ns otherwise
+ */
+struct uts_namespace *clone_uts_ns(struct uts_namespace *old_ns)
+{
+ struct uts_namespace *ns;
+
+ ns = kmalloc(sizeof(struct uts_namespace), GFP_KERNEL);
+ if (ns) {
+ memcpy(&ns->name, &old_ns->name, sizeof(ns->name));
+ kref_init(&ns->kref);
+ }
+ return ns;
+}
+
+/*
+ * unshare the current process' utsname namespace. Changes
+ * to the utsname of this process won't be seen by parent, and
+ * vice versa
+ *
+ * Return NULL on error (failure to kmalloc), new ns otherwise
+ *
+ * TODO: decide where this should be locked (depends on how/where
+ * we decide to use this)
+ */
+struct uts_namespace *unshare_uts_ns(void)
+{
+ struct uts_namespace *old_ns = current->uts_ns;
+ struct uts_namespace *new_ns = clone_uts_ns(old_ns);
+ if (new_ns) {
+ current->uts_ns = new_ns;
+ put_uts_ns(old_ns);
+ }
+ return new_ns;
+}
+EXPORT_SYMBOL(unshare_uts_ns);
+
+void free_uts_ns(struct kref *kref)
+{
+ struct uts_namespace *ns;
+
+ ns = container_of(kref, struct uts_namespace, kref);
+ kfree(ns);
+}
+EXPORT_SYMBOL(free_uts_ns);
+#endif

const char linux_banner[] =
"Linux version " UTS_RELEASE " (" LINUX_COMPILE_BY "@"
diff --git a/kernel/exit.c b/kernel/exit.c
index 6c2eeb8..97c5405 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -34,6 +34,7 @@
#include <linux/mutex.h>
#include <linux/futex.h>
#include <linux/compat.h>
+#include <linux/utsname.h>

#include <asm/uaccess.h>
#include <asm/unistd.h>
@@ -173,6 +174,7 @@ repeat:
spin_unlock(&p->proc_lock);
proc_pid_flush(proc_dentry);
release_thread(p);
+ put_uts_ns(p->uts_ns);
call_rcu(&p->rcu, delayed_put_task_struct);

p = leader;
diff --git a/kernel/fork.c b/kernel/fork.c
index 3384eb8..62e4479 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -44,6 +44,7 @@
#include <linux/rmap.h>
#include <linux/acct.h>
#include <linux/cn_proc.h>
+#include <linux/utsname.h>

#include <asm/pgtable.h>
#include <asm/pgalloc.h>
@@ -1119,6 +1120,8 @@ static task_t *copy_process(unsigned lon
/* Perform scheduler related setup. Assign this task to a CPU. */
sched_fork(p, clone_flags);

+ get_uts_ns(p->uts_ns);
+
/* Need tasklist lock for parent etc handling! */
write_lock_irq(&tasklist_lock);

@@ -1158,7 +1161,7 @@ static task_t *copy_process(unsigned lon
spin_unlock(&current->sighand->siglock);
write_unlock_irq(&tasklist_lock);
retval = -ERESTARTNOINTR;
- goto bad_fork_cleanup_namespace;
+ goto bad_fork_cleanup_utsns;
}

if (clone_flags & CLONE_THREAD) {
@@ -1171,7 +1174,7 @@ static task_t *copy_process(unsigned lon
spin_unlock(&current->sighand->siglock);
write_unlock_irq(&tasklist_lock);
retval = -EAGAIN;
- goto bad_fork_cleanup_namespace;
+ goto bad_fork_cleanup_utsns;
}

p->group_leader = current->group_leader;
@@ -1223,6 +1226,8 @@ static task_t *copy_process(unsigned lon
proc_fork_connector(p);
return p;

+bad_fork_cleanup_utsns:
+ put_uts_ns(p->uts_ns);
bad_fork_cleanup_namespace:
exit_namespace(p);
bad_fork_cleanup_keys:
--
1.2.4

Report message to a moderator

[Message index]
 
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Previous Topic: Projet openvz
Next Topic: [PATCH COMMIT] diff-merge-2.6.15.5-20060413
Goto Forum:
  

[ Syndicate this forum (XML) ] [ RSS ] [ PDF ]

Current Time: Sat Aug 30 16:04:06 GMT 2025

Total time taken to generate the page: 0.10268 seconds
Powered by FUDforum Powered by Virtuozzo Containers