Currently we have a bunch of pid namespace logic unnecessarily
scattered through fork, this patch moves it into copy_pid_ns
where it is easy to find and review.
To do this the prototype of copy_pid_ns is changed to take
a task parameter and the pid passed into copy_process
is passed in the task_pid field of that task.
After this cleanup things are actually clean enough we can contemplate
what an unshare of the pid namespace would mean.
Signed-off-by: Eric W. Biederman <[EMAIL PROTECTED]>
---
include/linux/pid_namespace.h | 5 +++--
kernel/fork.c | 16 +++++-----------
kernel/nsproxy.c | 2 +-
kernel/pid_namespace.c | 31 ++++++++++++++++++++++++++++---
4 files changed, 37 insertions(+), 17 deletions(-)
diff --git a/include/linux/pid_namespace.h b/include/linux/pid_namespace.h
index 2e67033..8e2e346 100644
--- a/include/linux/pid_namespace.h
+++ b/include/linux/pid_namespace.h
@@ -37,7 +37,7 @@ static inline struct pid_namespace *get_pid_ns(struct
pid_namespace *ns)
return ns;
}
-extern struct pid_namespace *copy_pid_ns(unsigned long flags, struct
pid_namespace *ns);
+extern struct pid_namespace *copy_pid_ns(unsigned long flags, struct
task_struct *tsk);
extern void free_pid_ns(struct kref *kref);
extern void zap_pid_ns_processes(struct pid_namespace *pid_ns);
@@ -56,8 +56,9 @@ static inline struct pid_namespace *get_pid_ns(struct
pid_namespace *ns)
}
static inline struct pid_namespace *
-copy_pid_ns(unsigned long flags, struct pid_namespace *ns)
+copy_pid_ns(unsigned long flags, struct task_struct *task)
{
+ struct pid_namespace *ns = task->nsproxy->pid_ns;
if (flags & CLONE_NEWPID)
ns = ERR_PTR(-EINVAL);
return ns;
diff --git a/kernel/fork.c b/kernel/fork.c
index 20d26a5..bbd8bcd 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -50,7 +50,6 @@
#include <linux/taskstats_kern.h>
#include <linux/random.h>
#include <linux/tty.h>
-#include <linux/proc_fs.h>
#include <linux/memcontrol.h>
#include <asm/pgtable.h>
@@ -1013,6 +1012,9 @@ static struct task_struct *copy_process(unsigned long
clone_flags,
if (!p)
goto fork_out;
+ /* Remember the pid */
+ p->pids[PIDTYPE_PID].pid = pid;
+
rt_mutex_init_task(p);
#ifdef CONFIG_TRACE_IRQFLAGS
@@ -1162,17 +1164,12 @@ static struct task_struct *copy_process(unsigned long
clone_flags,
if (retval)
goto bad_fork_cleanup_namespaces;
- if (pid != &init_struct_pid) {
+ pid = task_pid(p);
+ if (!pid) {
retval = -ENOMEM;
pid = alloc_pid(p->nsproxy->pid_ns);
if (!pid)
goto bad_fork_cleanup_namespaces;
-
- if (clone_flags & CLONE_NEWPID) {
- retval = pid_ns_prepare_proc(p->nsproxy->pid_ns);
- if (retval < 0)
- goto bad_fork_free_pid;
- }
}
p->pid = pid_nr(pid);
@@ -1304,9 +1301,6 @@ static struct task_struct *copy_process(unsigned long
clone_flags,
__ptrace_link(p, current->parent);
if (thread_group_leader(p)) {
- if (clone_flags & CLONE_NEWPID)
- p->nsproxy->pid_ns->child_reaper = pid;
-
p->signal->leader_pid = pid;
p->signal->tty = current->signal->tty;
set_task_pgrp(p, task_pgrp_nr(current));
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index f5d332c..7b6d2dc 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -75,7 +75,7 @@ static struct nsproxy *create_new_namespaces(unsigned long
flags,
goto out_ipc;
}
- new_nsp->pid_ns = copy_pid_ns(flags, task_active_pid_ns(tsk));
+ new_nsp->pid_ns = copy_pid_ns(flags, tsk);
if (IS_ERR(new_nsp->pid_ns)) {
err = PTR_ERR(new_nsp->pid_ns);
goto out_pid;
diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index 6d792b6..739a72b 100644
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -12,6 +12,7 @@
#include <linux/pid_namespace.h>
#include <linux/syscalls.h>
#include <linux/err.h>
+#include <linux/proc_fs.h>
#define BITS_PER_PAGE (PAGE_SIZE*8)
@@ -115,9 +116,12 @@ static void destroy_pid_namespace(struct pid_namespace *ns)
kmem_cache_free(pid_ns_cachep, ns);
}
-struct pid_namespace *copy_pid_ns(unsigned long flags, struct pid_namespace
*old_ns)
+struct pid_namespace *copy_pid_ns(unsigned long flags, struct task_struct *tsk)
{
+ struct pid_namespace *old_ns = tsk->nsproxy->pid_ns;
struct pid_namespace *new_ns;
+ struct pid *pid = NULL;
+ int err;
BUG_ON(!old_ns);
new_ns = get_pid_ns(old_ns);
@@ -129,13 +133,34 @@ struct pid_namespace *copy_pid_ns(unsigned long flags,
struct pid_namespace *old
goto out_put;
new_ns = create_pid_namespace(old_ns->level + 1);
- if (!IS_ERR(new_ns))
- new_ns->parent = get_pid_ns(old_ns);
+ if (IS_ERR(new_ns))
+ goto out_put;
+
+ new_ns->parent = get_pid_ns(old_ns);
+ pid = task_pid(tsk);
+ if (!pid) {
+ err = -ENOMEM;
+ tsk->pids[PIDTYPE_PID].pid = pid = alloc_pid(new_ns);
+ if (!pid)
+ goto out_put_new;
+ }
+
+ new_ns->child_reaper = pid;
+ err = pid_ns_prepare_proc(new_ns);
+ if (err)
+ goto out_put_new;
out_put:
put_pid_ns(old_ns);
out:
return new_ns;
+
+out_put_new:
+ if (pid)
+ free_pid(pid);
+ put_pid_ns(new_ns);
+ new_ns = ERR_PTR(err);
+ goto out_put;
}
void free_pid_ns(struct kref *kref)
--
1.5.3.rc6.17.g1911
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