[PATCH RFC 2/5] Syslog_ns: add CLONE_NEWSYSLOG and create syslog_ns when copying process
Rui Xiang
leo.ruixiang at gmail.com
Mon Nov 19 08:16:38 UTC 2012
From: Xiang Rui <rui.xiang at huawei.com>
We add a new clone flag named CLONE_NEWSYSLOG, and use 0x02000000 which was
previously the unused CLONE_STOPPED and is now available for re-use.
In syslog_namespaces.c, the interface copy_syslog_ns is implemented for create
a new syslog_ns. When a new namespace was created for one process copying, the
interface was used.
Signed-off-by: Xiang Rui <rui.xiang at huawei.com>
Signed-off-by: Libo Chen <clbchenlibo.chen at huawei.com>
---
include/linux/nsproxy.h | 2 ++
include/linux/syslog_namespace.h | 19 +++++++++++++++++++
include/uapi/linux/sched.h | 3 +--
kernel/nsproxy.c | 16 +++++++++++++++-
kernel/syslog_namespace.c | 32 ++++++++++++++++++++++++++++++++
5 files changed, 69 insertions(+), 3 deletions(-)
diff --git a/include/linux/nsproxy.h b/include/linux/nsproxy.h
index cc37a55..9db2527 100644
--- a/include/linux/nsproxy.h
+++ b/include/linux/nsproxy.h
@@ -8,6 +8,7 @@ struct mnt_namespace;
struct uts_namespace;
struct ipc_namespace;
struct pid_namespace;
+struct syslog_namespace;
struct fs_struct;
/*
@@ -29,6 +30,7 @@ struct nsproxy {
struct mnt_namespace *mnt_ns;
struct pid_namespace *pid_ns;
struct net *net_ns;
+ struct syslog_namespace *syslog_ns;
};
extern struct nsproxy init_nsproxy;
diff --git a/include/linux/syslog_namespace.h b/include/linux/syslog_namespace.h
index 8c8ac5a..1ecb8b8 100644
--- a/include/linux/syslog_namespace.h
+++ b/include/linux/syslog_namespace.h
@@ -2,6 +2,9 @@
#define _LINUX_SYSLOG_NAMESPACE_H
#include <linux/kref.h>
+#include <linux/sched.h>
+#include <linux/nsproxy.h>
+#include <linux/err.h>
/* record buffer */
#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
@@ -47,8 +50,16 @@ struct syslog_namespace {
extern struct syslog_namespace init_syslog_ns;
+static inline struct syslog_namespace *current_syslog_ns(void)
+{
+ return current->nsproxy->syslog_ns;
+}
+
#ifdef CONFIG_SYSLOG_NS
extern void free_syslog_ns(struct kref *kref);
+extern struct syslog_namespace *copy_syslog_ns(unsigned long flags,
+ struct task_struct *tsk);
+
static inline struct syslog_namespace *get_syslog_ns(
struct syslog_namespace *ns)
{
@@ -64,6 +75,14 @@ static inline void put_syslog_ns(struct syslog_namespace *ns)
}
#else
+static inline struct syslog_namespace *copy_syslog_ns(unsigned long flags,
+ struct task_struct *tsk)
+{
+ if (flags & CLONE_NEWSYSLOG)
+ return ERR_PTR(-EINVAL);
+ return tsk->nsproxy->syslog_ns;
+}
+
static inline struct syslog_namespace *get_syslog_ns(
struct syslog_namespace *ns)
{
diff --git a/include/uapi/linux/sched.h b/include/uapi/linux/sched.h
index 5a0f945..906a3da 100644
--- a/include/uapi/linux/sched.h
+++ b/include/uapi/linux/sched.h
@@ -21,8 +21,7 @@
#define CLONE_DETACHED 0x00400000 /* Unused, ignored */
#define CLONE_UNTRACED 0x00800000 /* set if the tracing process can't force CLONE_PTRACE on this clone */
#define CLONE_CHILD_SETTID 0x01000000 /* set the TID in the child */
-/* 0x02000000 was previously the unused CLONE_STOPPED (Start in stopped state)
- and is now available for re-use. */
+#define CLONE_NEWSYSLOG 0x02000000 /* New syslog namespace */
#define CLONE_NEWUTS 0x04000000 /* New utsname group? */
#define CLONE_NEWIPC 0x08000000 /* New ipcs */
#define CLONE_NEWUSER 0x10000000 /* New user namespace */
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index b576f7f..331d31f 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -22,6 +22,7 @@
#include <linux/pid_namespace.h>
#include <net/net_namespace.h>
#include <linux/ipc_namespace.h>
+#include <linux/syslog_namespace.h>
#include <linux/proc_fs.h>
#include <linux/file.h>
#include <linux/syscalls.h>
@@ -36,6 +37,7 @@ struct nsproxy init_nsproxy = {
#endif
.mnt_ns = NULL,
.pid_ns = &init_pid_ns,
+ .syslog_ns = &init_syslog_ns,
#ifdef CONFIG_NET
.net_ns = &init_net,
#endif
@@ -96,8 +98,17 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
goto out_net;
}
+ new_nsp->syslog_ns = copy_syslog_ns(flags, tsk);
+ if (IS_ERR(new_nsp->syslog_ns)) {
+ err = PTR_ERR(new_nsp->syslog_ns);
+ goto out_syslog;
+ }
+
return new_nsp;
+out_syslog:
+ if (new_nsp->net_ns)
+ put_net(new_nsp->net_ns);
out_net:
if (new_nsp->pid_ns)
put_pid_ns(new_nsp->pid_ns);
@@ -131,7 +142,8 @@ int copy_namespaces(unsigned long flags, struct task_struct *tsk)
get_nsproxy(old_ns);
if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
- CLONE_NEWPID | CLONE_NEWNET)))
+ CLONE_NEWPID | CLONE_NEWNET |
+ CLONE_NEWSYSLOG)))
return 0;
if (!capable(CAP_SYS_ADMIN)) {
@@ -174,6 +186,8 @@ void free_nsproxy(struct nsproxy *ns)
put_ipc_ns(ns->ipc_ns);
if (ns->pid_ns)
put_pid_ns(ns->pid_ns);
+ if (ns->syslog_ns)
+ put_syslog_ns(ns->syslog_ns);
put_net(ns->net_ns);
kmem_cache_free(nsproxy_cachep, ns);
}
diff --git a/kernel/syslog_namespace.c b/kernel/syslog_namespace.c
index 9482927..a12e1c1 100644
--- a/kernel/syslog_namespace.c
+++ b/kernel/syslog_namespace.c
@@ -7,6 +7,7 @@
#include <linux/slab.h>
#include <linux/module.h>
+#include <linux/bootmem.h>
#include <linux/syslog_namespace.h>
static char __log_buf[__LOG_BUF_LEN] __aligned(LOG_ALIGN);
@@ -21,6 +22,37 @@ struct syslog_namespace init_syslog_ns = {
};
EXPORT_SYMBOL_GPL(init_syslog_ns);
+static struct syslog_namespace *create_syslog_ns(unsigned int buf_len)
+{
+ struct syslog_namespace *ns;
+
+ if (buf_len <= 0)
+ return ERR_PTR(-EINVAL);
+ ns = kzalloc(sizeof(*ns), GFP_KERNEL);
+ if (!ns)
+ return ERR_PTR(-ENOMEM);
+
+ kref_init(&(ns->kref));
+
+ ns->log_buf_len = buf_len;
+ ns->log_buf = kzalloc(buf_len, GFP_KERNEL);
+ if (!ns->log_buf) {
+ kfree(ns);
+ return ERR_PTR(-ENOMEM);
+ }
+ raw_spin_lock_init(&(ns->logbuf_lock));
+
+ return ns;
+}
+
+struct syslog_namespace *copy_syslog_ns(unsigned long flags,
+ struct task_struct *tsk)
+{
+ if (!(flags & CLONE_NEWSYSLOG))
+ return get_syslog_ns(tsk->nsproxy->syslog_ns);
+ return create_syslog_ns(CONTAINER_BUF_LEN);
+}
+
void free_syslog_ns(struct kref *kref)
{
struct syslog_namespace *ns;
--
1.7.1
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