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[PATCH] namespaces: utsname: implement CLONE_NEWUTS flag

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Implement a CLONE_NEWUTS flag, and use it at clone and sys_unshare.

[clg@fr.ibm.com: IPC unshare fix]
[bunk@stusta.de: 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: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Serge E. Hallyn
2006-10-02 02:18:17 -07:00
committed by Linus Torvalds
parent bf47fdcda6
commit 071df104f8
5 changed files with 83 additions and 4 deletions
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53
kernel/utsname.c
View File

@@ -14,6 +14,41 @@
#include <linux/utsname.h>
#include <linux/version.h>
/*
* 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
*/
static 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.
* called only in sys_unshare()
*/
int unshare_utsname(unsigned long unshare_flags, struct uts_namespace **new_uts)
{
if (unshare_flags & CLONE_NEWUTS) {
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
*new_uts = clone_uts_ns(current->nsproxy->uts_ns);
if (!*new_uts)
return -ENOMEM;
}
return 0;
}
/*
* Copy task tsk's utsname namespace, or clone it if flags
* specifies CLONE_NEWUTS. In latter case, changes to the
@@ -23,6 +58,7 @@
int copy_utsname(int flags, struct task_struct *tsk)
{
struct uts_namespace *old_ns = tsk->nsproxy->uts_ns;
struct uts_namespace *new_ns;
int err = 0;
if (!old_ns)
@@ -30,6 +66,23 @@ int copy_utsname(int flags, struct task_struct *tsk)
get_uts_ns(old_ns);
if (!(flags & CLONE_NEWUTS))
return 0;
if (!capable(CAP_SYS_ADMIN)) {
err = -EPERM;
goto out;
}
new_ns = clone_uts_ns(old_ns);
if (!new_ns) {
err = -ENOMEM;
goto out;
}
tsk->nsproxy->uts_ns = new_ns;
out:
put_uts_ns(old_ns);
return err;
}