This is the largest patch in the set. Make all (I hope) the places where
the pid is shown to or get from user operate on the virtual pids.

The idea is:
 - all in-kernel data structures must store either struct pid itself
   or the pid's global nr, obtained with pid_nr() call;
 - when seeking the task from kernel code with the stored id one
   should use find_task_by_pid() call that works with global pids;
 - when showing pid's numerical value to the user the virtual one
   should be used, but however when one shows task's pid outside this
   task's namespace the global one is to be used;
 - when getting the pid from userspace one need to consider this as
   the virtual one and use appropriate task/pid-searching functions.

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

---

 arch/ia64/kernel/signal.c   |    4 ++--
 arch/parisc/kernel/signal.c |    2 +-
 drivers/char/tty_io.c       |    7 ++++---
 fs/binfmt_elf.c             |   16 ++++++++--------
 fs/binfmt_elf_fdpic.c       |   16 ++++++++--------
 fs/exec.c                   |    7 +++++--
 fs/proc/array.c             |   21 ++++++++++++++-------
 fs/proc/base.c              |   23 +++++++++++++++--------
 include/net/scm.h           |    4 +++-
 ipc/mqueue.c                |    4 +++-
 ipc/msg.c                   |    6 +++---
 ipc/sem.c                   |    8 ++++----
 ipc/shm.c                   |    6 +++---
 kernel/capability.c         |   13 ++++++++-----
 kernel/exit.c               |   31 ++++++++++++++++++++-----------
 kernel/fork.c               |   15 +++++++++++----
 kernel/futex.c              |   23 +++++++++++++----------
 kernel/ptrace.c             |    4 +++-
 kernel/sched.c              |    3 ++-
 kernel/signal.c             |   42 +++++++++++++++++++++++++++---------------
 kernel/sys.c                |   41 ++++++++++++++++++++++++++---------------
 kernel/timer.c              |    7 ++++---
 net/core/scm.c              |    4 +++-
 net/unix/af_unix.c          |    6 +++---
 24 files changed, 193 insertions(+), 120 deletions(-)

--- ./arch/ia64/kernel/signal.c.pidnshooks	2007-06-15 15:00:32.000000000 +0400
+++ ./arch/ia64/kernel/signal.c	2007-06-15 15:02:29.000000000 +0400
@@ -227,7 +227,7 @@ ia64_rt_sigreturn (struct sigscratch *sc
 	si.si_signo = SIGSEGV;
 	si.si_errno = 0;
 	si.si_code = SI_KERNEL;
-	si.si_pid = current->pid;
+	si.si_pid = task_pid_vnr(current);
 	si.si_uid = current->uid;
 	si.si_addr = sc;
 	force_sig_info(SIGSEGV, &si, current);
@@ -332,7 +332,7 @@ force_sigsegv_info (int sig, void __user
 	si.si_signo = SIGSEGV;
 	si.si_errno = 0;
 	si.si_code = SI_KERNEL;
-	si.si_pid = current->pid;
+	si.si_pid = task_pid_vnr(current);
 	si.si_uid = current->uid;
 	si.si_addr = addr;
 	force_sig_info(SIGSEGV, &si, current);
--- ./arch/parisc/kernel/signal.c.pidnshooks	2007-06-15 15:00:32.000000000 +0400
+++ ./arch/parisc/kernel/signal.c	2007-06-15 15:02:29.000000000 +0400
@@ -181,7 +181,7 @@ give_sigsegv:
 	si.si_signo = SIGSEGV;
 	si.si_errno = 0;
 	si.si_code = SI_KERNEL;
-	si.si_pid = current->pid;
+	si.si_pid = task_pid_vnr(current);
 	si.si_uid = current->uid;
 	si.si_addr = &frame->uc;
 	force_sig_info(SIGSEGV, &si, current);
--- ./drivers/char/tty_io.c.pidnshooks	2007-06-15 15:00:44.000000000 +0400
+++ ./drivers/char/tty_io.c	2007-06-15 15:02:29.000000000 +0400
@@ -103,6 +103,7 @@
 #include <linux/selection.h>
 
 #include <linux/kmod.h>
+#include <linux/nsproxy.h>
 
 #undef TTY_DEBUG_HANGUP
 
@@ -3062,7 +3063,7 @@ static int tiocgpgrp(struct tty_struct *
 	 */
 	if (tty == real_tty && current->signal->tty != real_tty)
 		return -ENOTTY;
-	return put_user(pid_nr(real_tty->pgrp), p);
+	return put_user(pid_vnr(real_tty->pgrp), p);
 }
 
 /**
@@ -3096,7 +3097,7 @@ static int tiocspgrp(struct tty_struct *
 	if (pgrp_nr < 0)
 		return -EINVAL;
 	rcu_read_lock();
-	pgrp = find_pid(pgrp_nr);
+	pgrp = find_vpid(pgrp_nr);
 	retval = -ESRCH;
 	if (!pgrp)
 		goto out_unlock;
@@ -3133,7 +3134,7 @@ static int tiocgsid(struct tty_struct *t
 		return -ENOTTY;
 	if (!real_tty->session)
 		return -ENOTTY;
-	return put_user(pid_nr(real_tty->session), p);
+	return put_user(pid_vnr(real_tty->session), p);
 }
 
 /**
--- ./fs/binfmt_elf.c.pidnshooks	2007-06-15 15:00:44.000000000 +0400
+++ ./fs/binfmt_elf.c	2007-06-15 15:02:29.000000000 +0400
@@ -1392,10 +1392,10 @@ static void fill_prstatus(struct elf_prs
 	prstatus->pr_info.si_signo = prstatus->pr_cursig = signr;
 	prstatus->pr_sigpend = p->pending.signal.sig[0];
 	prstatus->pr_sighold = p->blocked.sig[0];
-	prstatus->pr_pid = p->pid;
-	prstatus->pr_ppid = p->parent->pid;
-	prstatus->pr_pgrp = task_pgrp_nr(p);
-	prstatus->pr_sid = task_session_nr(p);
+	prstatus->pr_pid = task_pid_vnr(p);
+	prstatus->pr_ppid = task_pid_vnr(p->parent);
+	prstatus->pr_pgrp = task_pgrp_vnr(p);
+	prstatus->pr_sid = task_session_vnr(p);
 	if (thread_group_leader(p)) {
 		/*
 		 * This is the record for the group leader.  Add in the
@@ -1438,10 +1438,10 @@ static int fill_psinfo(struct elf_prpsin
 			psinfo->pr_psargs[i] = ' ';
 	psinfo->pr_psargs[len] = 0;
 
-	psinfo->pr_pid = p->pid;
-	psinfo->pr_ppid = p->parent->pid;
-	psinfo->pr_pgrp = task_pgrp_nr(p);
-	psinfo->pr_sid = task_session_nr(p);
+	psinfo->pr_pid = task_pid_vnr(p);
+	psinfo->pr_ppid = task_pid_vnr(p->parent);
+	psinfo->pr_pgrp = task_pgrp_vnr(p);
+	psinfo->pr_sid = task_session_vnr(p);
 
 	i = p->state ? ffz(~p->state) + 1 : 0;
 	psinfo->pr_state = i;
--- ./fs/binfmt_elf_fdpic.c.pidnshooks	2007-06-15 15:00:44.000000000 +0400
+++ ./fs/binfmt_elf_fdpic.c	2007-06-15 15:02:29.000000000 +0400
@@ -1342,10 +1342,10 @@ static void fill_prstatus(struct elf_prs
 	prstatus->pr_info.si_signo = prstatus->pr_cursig = signr;
 	prstatus->pr_sigpend = p->pending.signal.sig[0];
 	prstatus->pr_sighold = p->blocked.sig[0];
-	prstatus->pr_pid = p->pid;
-	prstatus->pr_ppid = p->parent->pid;
-	prstatus->pr_pgrp = task_pgrp_nr(p);
-	prstatus->pr_sid = task_session_nr(p);
+	prstatus->pr_pid = task_pid_vnr(p);
+	prstatus->pr_ppid = task_pid_vnr(p->parent);
+	prstatus->pr_pgrp = task_pgrp_vnr(p);
+	prstatus->pr_sid = task_session_vnr(p);
 	if (thread_group_leader(p)) {
 		/*
 		 * This is the record for the group leader.  Add in the
@@ -1391,10 +1391,10 @@ static int fill_psinfo(struct elf_prpsin
 			psinfo->pr_psargs[i] = ' ';
 	psinfo->pr_psargs[len] = 0;
 
-	psinfo->pr_pid = p->pid;
-	psinfo->pr_ppid = p->parent->pid;
-	psinfo->pr_pgrp = task_pgrp_nr(p);
-	psinfo->pr_sid = task_session_nr(p);
+	psinfo->pr_pid = task_pid_vnr(p);
+	psinfo->pr_ppid = task_pid_vnr(p->parent);
+	psinfo->pr_pgrp = task_pgrp_vnr(p);
+	psinfo->pr_sid = task_session_vnr(p);
 
 	i = p->state ? ffz(~p->state) + 1 : 0;
 	psinfo->pr_state = i;
--- ./fs/exec.c.pidnshooks	2007-06-15 15:00:32.000000000 +0400
+++ ./fs/exec.c	2007-06-15 15:02:29.000000000 +0400
@@ -716,6 +716,9 @@ static int de_thread(struct task_struct 
 		attach_pid(tsk, PIDTYPE_PID,  find_pid(tsk->pid));
 		transfer_pid(leader, tsk, PIDTYPE_PGID);
 		transfer_pid(leader, tsk, PIDTYPE_SID);
+		set_task_vpgrp(leader, task_pid_vnr(current));
+		set_task_vpid(leader, task_pid_vnr(current));
+		set_task_vtgid(current, task_pid_vnr(current));
 		list_replace_rcu(&leader->tasks, &tsk->tasks);
 
 		tsk->group_leader = tsk;
@@ -1304,7 +1307,7 @@ static int format_corename(char *corenam
 			case 'p':
 				pid_in_pattern = 1;
 				rc = snprintf(out_ptr, out_end - out_ptr,
-					      "%d", current->tgid);
+					      "%d", task_tgid_vnr(current));
 				if (rc > out_end - out_ptr)
 					goto out;
 				out_ptr += rc;
@@ -1376,7 +1379,7 @@ static int format_corename(char *corenam
 	if (!ispipe && !pid_in_pattern
             && (core_uses_pid || atomic_read(&current->mm->mm_users) != 1)) {
 		rc = snprintf(out_ptr, out_end - out_ptr,
-			      ".%d", current->tgid);
+			      ".%d", task_tgid_vnr(current));
 		if (rc > out_end - out_ptr)
 			goto out;
 		out_ptr += rc;
--- ./fs/proc/array.c.pidnshooks	2007-06-15 15:00:44.000000000 +0400
+++ ./fs/proc/array.c	2007-06-15 15:02:29.000000000 +0400
@@ -75,6 +75,7 @@
 #include <linux/cpuset.h>
 #include <linux/rcupdate.h>
 #include <linux/delayacct.h>
+#include <linux/pid_namespace.h>
 
 #include <asm/uaccess.h>
 #include <asm/pgtable.h>
@@ -161,7 +162,9 @@ static inline char * task_state(struct t
 	struct group_info *group_info;
 	int g;
 	struct fdtable *fdt = NULL;
+	struct pid_namespace *ns;
 
+	ns = current->nsproxy->pid_ns;
 	rcu_read_lock();
 	buffer += sprintf(buffer,
 		"State:\t%s\n"
@@ -172,9 +175,12 @@ static inline char * task_state(struct t
 		"Uid:\t%d\t%d\t%d\t%d\n"
 		"Gid:\t%d\t%d\t%d\t%d\n",
 		get_task_state(p),
-		p->tgid, p->pid,
-		pid_alive(p) ? rcu_dereference(p->real_parent)->tgid : 0,
-		pid_alive(p) && p->ptrace ? rcu_dereference(p->parent)->pid : 0,
+	       	task_tgid_nr_ns(p, ns),
+		task_pid_nr_ns(p, ns),
+	       	pid_alive(p) ?
+			task_ppid_nr_ns(p, ns) : 0,
+		pid_alive(p) && p->ptrace ?
+			task_tgid_nr_ns(rcu_dereference(p->parent), ns) : 0,
 		p->uid, p->euid, p->suid, p->fsuid,
 		p->gid, p->egid, p->sgid, p->fsgid);
 
@@ -382,6 +388,7 @@ static int do_task_stat(struct task_stru
 	rcu_read_lock();
 	if (lock_task_sighand(task, &flags)) {
 		struct signal_struct *sig = task->signal;
+		struct pid_namespace *ns = current->nsproxy->pid_ns;
 
 		if (sig->tty) {
 			tty_pgrp = pid_nr(sig->tty->pgrp);
@@ -414,9 +421,9 @@ static int do_task_stat(struct task_stru
 			stime += cputime_to_clock_t(sig->stime);
 		}