[RFC][PATCH 6/7][v2] Define do_fork_with_pids()

[Sukadev Bhattiprolu <sukadev-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>]

From: Sukadev Bhattiprolu <sukadev-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
Date: Mon, 4 May 2009 01:17:44 -0700
Subject: [RFC][PATCH 6/7][v2] Define do_fork_with_pids()

do_fork_with_pids() is same as do_fork(), except that it takes an
additional, 'pid_set', parameter. This parameter, currently unused,
specifies the set of target pids of the process in each of its pid
namespaces.

Changelog[v2]:
	- [v1] of this patch had some architecture-indpendent code in
	  arch/x86/kernel/process_32.c.  To facilitate moving this code
	  to kernel/fork.c, in the next patch, [v2] of the patch passes
	  'struct target_pid_set __user *' to do_fork_with_pids() instead
	  of 'pid_t *'.

Signed-off-by: Sukadev Bhattiprolu <sukadev-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
---
 include/linux/sched.h |    1 +
 include/linux/types.h |    5 +++++
 kernel/fork.c         |   16 ++++++++++++++--
 3 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index b4c38bc..8468e54 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1995,6 +1995,7 @@ extern int disallow_signal(int);
 
 extern int do_execve(char *, char __user * __user *, char __user * __user *, struct pt_regs *);
 extern long do_fork(unsigned long, unsigned long, struct pt_regs *, unsigned long, int __user *, int __user *);
+extern long do_fork_with_pids(unsigned long, unsigned long, struct pt_regs *, unsigned long, int __user *, int __user *, struct target_pid_set __user *pid_set);
 struct task_struct *fork_idle(int);
 
 extern void set_task_comm(struct task_struct *tsk, char *from);
diff --git a/include/linux/types.h b/include/linux/types.h
index 5abe354..17ec186 100644
--- a/include/linux/types.h
+++ b/include/linux/types.h
@@ -204,6 +204,11 @@ struct ustat {
 	char			f_fpack[6];
 };
 
+struct target_pid_set {
+	int num_pids;
+	pid_t *target_pids;
+};
+
 #endif	/* __KERNEL__ */
 #endif /*  __ASSEMBLY__ */
 #endif /* _LINUX_TYPES_H */
diff --git a/kernel/fork.c b/kernel/fork.c
index 373411e..a16ef7b 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1340,12 +1340,13 @@ struct task_struct * __cpuinit fork_idle(int cpu)
  * It copies the process, and if successful kick-starts
  * it and waits for it to finish using the VM if required.
  */
-long do_fork(unsigned long clone_flags,
+long do_fork_with_pids(unsigned long clone_flags,
 	      unsigned long stack_start,
 	      struct pt_regs *regs,
 	      unsigned long stack_size,
 	      int __user *parent_tidptr,
-	      int __user *child_tidptr)
+	      int __user *child_tidptr,
+	      struct target_pid_set __user *pid_setp)
 {
 	struct task_struct *p;
 	int trace = 0;
@@ -1448,6 +1449,17 @@ long do_fork(unsigned long clone_flags,
 	return nr;
 }
 
+long do_fork(unsigned long clone_flags,
+	      unsigned long stack_start,
+	      struct pt_regs *regs,
+	      unsigned long stack_size,
+	      int __user *parent_tidptr,
+	      int __user *child_tidptr)
+{
+	return do_fork_with_pids(clone_flags, stack_start, regs, stack_size,
+			parent_tidptr, child_tidptr, NULL);
+}
+
 #ifndef ARCH_MIN_MMSTRUCT_ALIGN
 #define ARCH_MIN_MMSTRUCT_ALIGN 0
 #endif
-- 
1.5.2.5