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[PATCH 8/15] Helpers to find the task by its numerical ids [message #15302 is a reply to message #15293]

Thu, 26 July 2007 14:51

Pavel Emelianov
Messages: 1149
Registered: September 2006

Senior Member

When searching the task by numerical id on may need to find
it using global pid (as it is done now in kernel) or by its
virtual id, e.g. when sending a signal to a task from one
namespace the sender will specify the task's virtual id.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>

---

include/linux/pid.h | 16 ++++++++++++++--
include/linux/sched.h | 31 +++++++++++++++++++++++++++++--
kernel/pid.c | 32 +++++++++++++++++---------------
3 files changed, 60 insertions(+), 19 deletions(-)

diff -upr linux-2.6.23-rc1-mm1.orig/include/linux/pid.h linux-2.6.23-rc1-mm1-7/include/linux/pid.h
--- linux-2.6.23-rc1-mm1.orig/include/linux/pid.h 2007-07-26 16:34:45.000000000 +0400
+++ linux-2.6.23-rc1-mm1-7/include/linux/pid.h 2007-07-26 16:36:37.000000000 +0400
@@ -83,17 +92,29 @@ extern void FASTCALL(detach_pid(struct t
extern void FASTCALL(transfer_pid(struct task_struct *old,
struct task_struct *new, enum pid_type));

+struct pid_namespace;
+extern struct pid_namespace init_pid_ns;
+
/*
* look up a PID in the hash table. Must be called with the tasklist_lock
* or rcu_read_lock() held.
+ *
+ * find_pid_ns() finds the pid in the namespace specified
+ * find_pid() find the pid by its global id, i.e. in the init namespace
+ * find_vpid() finr the pid by its virtual id, i.e. in the current namespace
+ *
+ * see also find_task_by_pid() set in include/linux/sched.h
*/
-extern struct pid *FASTCALL(find_pid(int nr));
+extern struct pid *FASTCALL(find_pid_ns(int nr, struct pid_namespace *ns));
+
+#define find_vpid(pid) find_pid_ns(pid, current->nsproxy->pid_ns)
+#define find_pid(pid) find_pid_ns(pid, &init_pid_ns)

/*
* Lookup a PID in the hash table, and return with it's count elevated.
*/
extern struct pid *find_get_pid(int nr);
-extern struct pid *find_ge_pid(int nr);
+extern struct pid *find_ge_pid(int nr, struct pid_namespace *);

extern struct pid *alloc_pid(struct pid_namespace *ns);
extern void FASTCALL(free_pid(struct pid *pid));
diff -upr linux-2.6.23-rc1-mm1.orig/include/linux/sched.h linux-2.6.23-rc1-mm1-7/include/linux/sched.h
--- linux-2.6.23-rc1-mm1.orig/include/linux/sched.h 2007-07-26 16:34:45.000000000 +0400
+++ linux-2.6.23-rc1-mm1-7/include/linux/sched.h 2007-07-26 16:36:37.000000000 +0400
@@ -1453,8 +1542,35 @@ extern struct task_struct init_task;

extern struct mm_struct init_mm;

-#define find_task_by_pid(nr) find_task_by_pid_type(PIDTYPE_PID, nr)
-extern struct task_struct *find_task_by_pid_type(int type, int pid);
+extern struct pid_namespace init_pid_ns;
+
+/*
+ * find a task by one of its numerical ids
+ *
+ * find_task_by_pid_type_ns():
+ * it is the most generic call - it finds a task by all id,
+ * type and namespace specified
+ * find_task_by_pid_ns():
+ * finds a task by its pid in the specified namespace
+ * find_task_by_pid_type():
+ * finds a task by its global id with the specified type, e.g.
+ * by global session id
+ * find_task_by_pid():
+ * finds a task by its global pid
+ *
+ * see also find_pid() etc in include/linux/pid.h
+ */
+
+extern struct task_struct *find_task_by_pid_type_ns(int type, int pid,
+ struct pid_namespace *ns);
+
+#define find_task_by_pid_ns(nr, ns) \
+ find_task_by_pid_type_ns(PIDTYPE_PID, nr, ns)
+#define find_task_by_pid_type(type, nr) \
+ find_task_by_pid_type_ns(type, nr, &init_pid_ns)
+#define find_task_by_pid(nr) \
+ find_task_by_pid_type(PIDTYPE_PID, nr)
+
extern void __set_special_pids(pid_t session, pid_t pgrp);

/* per-UID process charging. */
diff -upr linux-2.6.23-rc1-mm1.orig/kernel/pid.c linux-2.6.23-rc1-mm1-7/kernel/pid.c
--- linux-2.6.23-rc1-mm1.orig/kernel/pid.c 2007-07-26 16:34:45.000000000 +0400
+++ linux-2.6.23-rc1-mm1-7/kernel/pid.c 2007-07-26 16:36:37.000000000 +0400
@@ -204,19 +221,20 @@ static void delayed_put_pid(struct rcu_h
goto out;
}

-struct pid * fastcall find_pid(int nr)
+struct pid * fastcall find_pid_ns(int nr, struct pid_namespace *ns)
{
struct hlist_node *elem;
- struct pid *pid;
+ struct upid *pnr;
+
+ hlist_for_each_entry_rcu(pnr, elem,
+ &pid_hash[pid_hashfn(nr, ns)], pid_chain)
+ if (pnr->nr == nr && pnr->ns == ns)
+ return container_of(pnr, struct pid,
+ numbers[ns->level]);

- hlist_for_each_entry_rcu(pid, elem,
- &pid_hash[pid_hashfn(nr)], pid_chain) {
- if (pid->nr == nr)
- return pid;
- }
return NULL;
}
-EXPORT_SYMBOL_GPL(find_pid);
+EXPORT_SYMBOL_GPL(find_pid_ns);

/*
* attach_pid() must be called with the tasklist_lock write-held.
@@ -318,12 +355,13 @@ struct task_struct * fastcall pid_task(s
/*
* Must be called under rcu_read_lock() or with tasklist_lock read-held.
*/
-struct task_struct *find_task_by_pid_type(int type, int nr)
+struct task_struct *find_task_by_pid_type_ns(int type, int nr,
+ struct pid_namespace *ns)
{
- return pid_task(find_pid(nr), type);
+ return pid_task(find_pid_ns(nr, ns), type);
}

-EXPORT_SYMBOL(find_task_by_pid_type);
+EXPORT_SYMBOL(find_task_by_pid_type_ns);

struct pid *get_task_pid(struct task_struct *task, enum pid_type type)
{
@@ -342,7 +426,7 @@ struct pid *find_get_pid(pid_t nr)
struct pid *pid;

rcu_read_lock();
- pid = get_pid(find_pid(nr));
+ pid = get_pid(find_vpid(nr));
rcu_read_unlock();

return pid;
@@ -352,15 +436,15 @@ struct pid *find_get_pid(pid_t nr)
*
* If there is a pid at nr this function is exactly the same as find_pid.
*/
-struct pid *find_ge_pid(int nr)
+struct pid *find_ge_pid(int nr, struct pid_namespace *ns)
{
struct pid *pid;

do {
- pid = find_pid(nr);
+ pid = find_pid_ns(nr, ns);
if (pid)
break;
- nr = next_pidmap(task_active_pid_ns(current), nr);
+ nr = next_pidmap(ns, nr);
} while (nr > 0);

return pid;

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[Message index]

		[RFC][PATCH 0/15] Pid namespaces By: Pavel Emelianov on Thu, 26 July 2007 14:45
		[PATCH 1/15] Move exit_task_namespaces() By: Pavel Emelianov on Thu, 26 July 2007 14:46
		Re: [PATCH 1/15] Move exit_task_namespaces() By: Oleg Nesterov on Thu, 26 July 2007 16:47
		Re: [PATCH 1/15] Move exit_task_namespaces() By: Oleg Nesterov on Fri, 27 July 2007 08:07
		Re: [PATCH 1/15] Move exit_task_namespaces() By: Pavel Emelianov on Fri, 27 July 2007 08:24
		Re: [PATCH 1/15] Move exit_task_namespaces() By: Oleg Nesterov on Fri, 27 July 2007 08:35
		Re: [PATCH 1/15] Move exit_task_namespaces() By: Pavel Emelianov on Fri, 27 July 2007 08:37
		Re: [PATCH 1/15] Move exit_task_namespaces() By: dev on Thu, 26 July 2007 16:59
		Re: [PATCH 1/15] Move exit_task_namespaces() By: Dave Hansen on Thu, 26 July 2007 16:10
		Re: [PATCH 1/15] Move exit_task_namespaces() By: xemul on Fri, 27 July 2007 06:38
		Re: [PATCH 1/15] Move exit_task_namespaces() By: Oleg Nesterov on Thu, 02 August 2007 16:18
		Re: [PATCH 1/15] Move exit_task_namespaces() By: Pavel Emelianov on Mon, 06 August 2007 08:00
		Re: [PATCH 1/15] Move exit_task_namespaces() By: Oleg Nesterov on Mon, 06 August 2007 09:54
		Re: [PATCH 1/15] Move exit_task_namespaces() By: Pavel Emelianov on Mon, 06 August 2007 09:58
		Re: [PATCH 1/15] Move exit_task_namespaces() By: Oleg Nesterov on Mon, 06 August 2007 10:38
		Re: [PATCH 1/15] Move exit_task_namespaces() By: Pavel Emelianov on Mon, 06 August 2007 11:21
		Re: [PATCH 1/15] Move exit_task_namespaces() By: Oleg Nesterov on Mon, 06 August 2007 12:52
		Re: [PATCH 1/15] Move exit_task_namespaces() By: Pavel Emelianov on Mon, 06 August 2007 13:38
		Re: [PATCH 1/15] Move exit_task_namespaces() By: Pavel Emelianov on Mon, 06 August 2007 11:29
		Re: [PATCH 1/15] Move exit_task_namespaces() By: Oleg Nesterov on Mon, 06 August 2007 12:48
		Re: [PATCH 1/15] Move exit_task_namespaces() By: Pavel Emelianov on Mon, 06 August 2007 13:36
		Re: [PATCH 1/15] Move exit_task_namespaces() By: Oleg Nesterov on Mon, 06 August 2007 13:55
		[PATCH 2/15] Introduce MS_KERNMOUNT flag By: Pavel Emelianov on Thu, 26 July 2007 14:47
		[PATCH 3/15] kern_siginfo helper By: Pavel Emelianov on Thu, 26 July 2007 14:48
		Re: [PATCH 3/15] kern_siginfo helper By: Oleg Nesterov on Sun, 29 July 2007 11:40
		Re: [PATCH 3/15] kern_siginfo helper By: Pavel Emelianov on Mon, 30 July 2007 06:07
		Re: [PATCH 3/15] kern_siginfo helper By: Sukadev Bhattiprolu on Tue, 31 July 2007 00:21
		[PATCH 4/15] Make proc_flust_task() flush entries from multiple proc trees By: Pavel Emelianov on Thu, 26 July 2007 14:48
		[PATCH 5/15] Introduce struct upid By: Pavel Emelianov on Thu, 26 July 2007 14:49
		Re: [PATCH 5/15] Introduce struct upid By: Oleg Nesterov on Sun, 29 July 2007 09:50
		Re: [PATCH 5/15] Introduce struct upid By: Pavel Emelianov on Mon, 30 July 2007 05:58
		[PATCH 6/15] Make alloc_pid(), free_pid() and put_pid() work with struct upid By: Pavel Emelianov on Thu, 26 July 2007 14:50
		Re: [PATCH 6/15] Make alloc_pid(), free_pid() and put_pid() work with struct upid By: Oleg Nesterov on Sun, 29 July 2007 10:14
		Re: [PATCH 6/15] Make alloc_pid(), free_pid() and put_pid() work with struct upid By: Pavel Emelianov on Mon, 30 July 2007 06:03
		[PATCH 7/15] Helpers to obtain pid numbers By: Pavel Emelianov on Thu, 26 July 2007 14:51
		Re: [PATCH 7/15] Helpers to obtain pid numbers By: Dave Hansen on Thu, 26 July 2007 19:03
		Re: [PATCH 7/15] Helpers to obtain pid numbers By: Pavel Emelianov on Fri, 27 July 2007 06:40
		Re: [PATCH 7/15] Helpers to obtain pid numbers By: Oleg Nesterov on Sun, 29 July 2007 12:08
		Re: [PATCH 7/15] Helpers to obtain pid numbers By: Pavel Emelianov on Mon, 30 July 2007 06:11
		[PATCH 8/15] Helpers to find the task by its numerical ids By: Pavel Emelianov on Thu, 26 July 2007 14:51
		Re: [PATCH 8/15] Helpers to find the task by its numerical ids By: Dave Hansen on Thu, 26 July 2007 19:05
		Re: [PATCH 8/15] Helpers to find the task by its numerical ids By: Pavel Emelianov on Fri, 27 July 2007 06:43
		Re: [PATCH 8/15] Helpers to find the task by its numerical ids By: Oleg Nesterov on Sun, 29 July 2007 12:39
		Re: [PATCH 8/15] Helpers to find the task by its numerical ids By: Pavel Emelianov on Mon, 30 July 2007 06:15
		[PATCH 9/15] Move alloc_pid() after the namespace is cloned By: Pavel Emelianov on Thu, 26 July 2007 14:52
		Re: [PATCH 9/15] Move alloc_pid() after the namespace is cloned By: Oleg Nesterov on Fri, 27 July 2007 15:10
		Re: [PATCH 9/15] Move alloc_pid() after the namespace is cloned By: Pavel Emelianov on Mon, 30 July 2007 06:17
		Re: [PATCH 9/15] Move alloc_pid() after the namespace is cloned By: Sukadev Bhattiprolu on Mon, 30 July 2007 23:43
		Re: [PATCH 9/15] Move alloc_pid() after the namespace is cloned By: Sukadev Bhattiprolu on Tue, 31 July 2007 05:49
		[PATCH 10/15] Make each namespace has its own proc tree By: Pavel Emelianov on Thu, 26 July 2007 14:54
		Re: [PATCH 10/15] Make each namespace has its own proc tree By: Oleg Nesterov on Sun, 29 July 2007 15:56
		Re: [PATCH 10/15] Make each namespace has its own proc tree By: Oleg Nesterov on Sun, 29 July 2007 17:02
		Re: [PATCH 10/15] Make each namespace has its own proc tree By: Pavel Emelianov on Mon, 30 July 2007 06:45
		Re: [PATCH 10/15] Make each namespace has its own proc tree By: Pavel Emelianov on Mon, 30 July 2007 06:43
		[PATCH 11/15] Signal semantics By: Pavel Emelianov on Thu, 26 July 2007 14:55
		Re: [PATCH 11/15] Signal semantics By: Oleg Nesterov on Fri, 27 July 2007 12:30
		Re: [PATCH 11/15] Signal semantics By: Pavel Emelianov on Fri, 27 July 2007 13:38
		Re: [PATCH 11/15] Signal semantics By: serue on Fri, 27 July 2007 19:59
		Re: [PATCH 11/15] Signal semantics By: Sukadev Bhattiprolu on Fri, 27 July 2007 20:23
		Re: [PATCH 11/15] Signal semantics By: Pavel Emelianov on Mon, 30 July 2007 09:34
		Re: [PATCH 11/15] Signal semantics By: Pavel Emelianov on Mon, 30 July 2007 09:31
		Re: [PATCH 11/15] Signal semantics By: serue on Wed, 01 August 2007 16:13
		Re: [PATCH 11/15] Signal semantics By: dev on Thu, 02 August 2007 08:35
		Re: [PATCH 11/15] Signal semantics By: serue on Thu, 02 August 2007 20:09
		Re: [PATCH 11/15] Signal semantics By: Oleg Nesterov on Sun, 29 July 2007 11:23
		[PATCH 12/15] Miscelaneous stuff for pid namespaces By: Pavel Emelianov on Thu, 26 July 2007 14:56
		Re: [PATCH 12/15] Miscelaneous stuff for pid namespaces By: Pavel Emelianov on Fri, 27 July 2007 06:53
		Re: [PATCH 12/15] Miscelaneous stuff for pid namespaces By: Sukadev Bhattiprolu on Fri, 27 July 2007 06:22
		[PATCH 13/15] Clone the pid namespace By: Pavel Emelianov on Thu, 26 July 2007 14:56
		[PATCH 14/15] Destroy pid namespace on init's death By: Pavel Emelianov on Thu, 26 July 2007 14:57
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Oleg Nesterov on Sun, 29 July 2007 10:39
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Pavel Emelianov on Mon, 30 July 2007 11:56
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Oleg Nesterov on Mon, 30 July 2007 15:44
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Oleg Nesterov on Tue, 31 July 2007 09:07
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Sukadev Bhattiprolu on Wed, 01 August 2007 06:16
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Dave Hansen on Wed, 01 August 2007 16:00
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Oleg Nesterov on Wed, 01 August 2007 19:51
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: dev on Thu, 02 August 2007 08:37
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Oleg Nesterov on Thu, 02 August 2007 16:08
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Oleg Nesterov on Thu, 02 August 2007 17:08
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Sukadev Bhattiprolu on Fri, 03 August 2007 06:22
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Oleg Nesterov on Fri, 03 August 2007 10:55
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Sukadev Bhattiprolu on Thu, 02 August 2007 07:37
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Oleg Nesterov on Wed, 01 August 2007 19:48
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Sukadev Bhattiprolu on Thu, 02 August 2007 07:29
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Oleg Nesterov on Thu, 02 August 2007 15:39
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Sukadev Bhattiprolu on Thu, 02 August 2007 17:20
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Oleg Nesterov on Thu, 02 August 2007 17:29
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Sukadev Bhattiprolu on Thu, 02 August 2007 18:36
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Oleg Nesterov on Thu, 02 August 2007 18:49
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: serue on Thu, 02 August 2007 19:13
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Sukadev Bhattiprolu on Fri, 03 August 2007 21:36
		[PATCH 15/15] Hooks over the code to show correct values to user By: Pavel Emelianov on Thu, 26 July 2007 14:58
		Re: [PATCH 15/15] Hooks over the code to show correct values to user By: Sukadev Bhattiprolu on Fri, 27 July 2007 05:57
		Re: [PATCH 15/15] Hooks over the code to show correct values to user By: Pavel Emelianov on Fri, 27 July 2007 06:44
		Re: [PATCH 15/15] Hooks over the code to show correct values to user By: Oleg Nesterov on Sun, 29 July 2007 14:29
		Re: [PATCH 15/15] Hooks over the code to show correct values to user By: Pavel Emelianov on Mon, 30 July 2007 06:49
		Re: [PATCH 15/15] Hooks over the code to show correct values to user By: Oleg Nesterov on Tue, 31 July 2007 10:04
		Re: [RFC][PATCH 0/15] Pid namespaces By: Sukadev Bhattiprolu on Fri, 27 July 2007 04:22
		Re: [RFC][PATCH 0/15] Pid namespaces By: Sukadev Bhattiprolu on Fri, 27 July 2007 06:08
		Re: [RFC][PATCH 0/15] Pid namespaces By: Pavel Emelianov on Fri, 27 July 2007 06:47

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