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authorCyrill Gorcunov <gorcunov@openvz.org>2012-07-31 01:43:00 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2012-07-31 04:25:21 +0400
commit1d151c337d79fa3de88654d2514f58fbd916a8e0 (patch)
tree79f96ea4b081f310aa62246e879224467b092261 /fs
parent65fed8f6f23070b56d0ed3841173ddd410130a89 (diff)
downloadlinux-1d151c337d79fa3de88654d2514f58fbd916a8e0.tar.xz
c/r: fcntl: add F_GETOWNER_UIDS option
When we restore file descriptors we would like them to look exactly as they were at dumping time. With help of fcntl it's almost possible, the missing snippet is file owners UIDs. To be able to read their values the F_GETOWNER_UIDS is introduced. This option is valid iif CONFIG_CHECKPOINT_RESTORE is turned on, otherwise returning -EINVAL. Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/fcntl.c29
1 files changed, 29 insertions, 0 deletions
diff --git a/fs/fcntl.c b/fs/fcntl.c
index 81b70e665bf0..887b5ba8c9b5 100644
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -20,6 +20,7 @@
#include <linux/signal.h>
#include <linux/rcupdate.h>
#include <linux/pid_namespace.h>
+#include <linux/user_namespace.h>
#include <asm/poll.h>
#include <asm/siginfo.h>
@@ -340,6 +341,31 @@ static int f_getown_ex(struct file *filp, unsigned long arg)
return ret;
}
+#ifdef CONFIG_CHECKPOINT_RESTORE
+static int f_getowner_uids(struct file *filp, unsigned long arg)
+{
+ struct user_namespace *user_ns = current_user_ns();
+ uid_t * __user dst = (void * __user)arg;
+ uid_t src[2];
+ int err;
+
+ read_lock(&filp->f_owner.lock);
+ src[0] = from_kuid(user_ns, filp->f_owner.uid);
+ src[1] = from_kuid(user_ns, filp->f_owner.euid);
+ read_unlock(&filp->f_owner.lock);
+
+ err = put_user(src[0], &dst[0]);
+ err |= put_user(src[1], &dst[1]);
+
+ return err;
+}
+#else
+static int f_getowner_uids(struct file *filp, unsigned long arg)
+{
+ return -EINVAL;
+}
+#endif
+
static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
struct file *filp)
{
@@ -396,6 +422,9 @@ static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
case F_SETOWN_EX:
err = f_setown_ex(filp, arg);
break;
+ case F_GETOWNER_UIDS:
+ err = f_getowner_uids(filp, arg);
+ break;
case F_GETSIG:
err = filp->f_owner.signum;
break;