[PATCH v3 04/11] rlimits: split sys_setrlimit

[Jiri Slaby <jslaby@suse.cz>]

From: Jiri Slaby <jirislaby@gmail.com>

Create do_setrlimit from sys_setrlimit and declare do_setrlimit
in the resource header. This is the firts phase to have generic
do_prlimit which allows to be called from read, write and compat
rlimits code.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 include/linux/resource.h |    2 ++
 kernel/sys.c             |   40 ++++++++++++++++++++++++----------------
 2 files changed, 26 insertions(+), 16 deletions(-)

diff --git a/include/linux/resource.h b/include/linux/resource.h
index f1e914e..cf8dc96 100644
--- a/include/linux/resource.h
+++ b/include/linux/resource.h
@@ -73,6 +73,8 @@ struct rlimit {
 struct task_struct;
 
 int getrusage(struct task_struct *p, int who, struct rusage __user *ru);
+int do_setrlimit(struct task_struct *tsk, unsigned int resource,
+		struct rlimit *new_rlim);
 
 #endif /* __KERNEL__ */
 
diff --git a/kernel/sys.c b/kernel/sys.c
index d527c46..7c76f84 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -1272,42 +1272,41 @@ SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
 
 #endif
 
-SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim)
+int do_setrlimit(struct task_struct *tsk, unsigned int resource,
+		struct rlimit *new_rlim)
 {
-	struct rlimit new_rlim, *old_rlim;
+	struct rlimit *old_rlim;
 	int retval;
 
 	if (resource >= RLIM_NLIMITS)
 		return -EINVAL;
-	if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
-		return -EFAULT;
-	if (new_rlim.rlim_cur > new_rlim.rlim_max)
+	if (new_rlim->rlim_cur > new_rlim->rlim_max)
 		return -EINVAL;
-	if (resource == RLIMIT_NOFILE && new_rlim.rlim_max > sysctl_nr_open)
+	if (resource == RLIMIT_NOFILE && new_rlim->rlim_max > sysctl_nr_open)
 		return -EPERM;
 
-	retval = security_task_setrlimit(current, resource, &new_rlim);
+	retval = security_task_setrlimit(tsk, resource, new_rlim);
 	if (retval)
 		return retval;
 
-	if (resource == RLIMIT_CPU && new_rlim.rlim_cur == 0) {
+	if (resource == RLIMIT_CPU && new_rlim->rlim_cur == 0) {
 		/*
 		 * The caller is asking for an immediate RLIMIT_CPU
 		 * expiry.  But we use the zero value to mean "it was
 		 * never set".  So let's cheat and make it one second
 		 * instead
 		 */
-		new_rlim.rlim_cur = 1;
+		new_rlim->rlim_cur = 1;
 	}
 
-	old_rlim = current->signal->rlim + resource;
-	task_lock(current->group_leader);
-	if ((new_rlim.rlim_max <= old_rlim->rlim_max) ||
+	old_rlim = tsk->signal->rlim + resource;
+	task_lock(tsk->group_leader);
+	if ((new_rlim->rlim_max <= old_rlim->rlim_max) ||
 				capable(CAP_SYS_RESOURCE))
-		*old_rlim = new_rlim;
+		*old_rlim = *new_rlim;
 	else
 		retval = -EPERM;
-	task_unlock(current->group_leader);
+	task_unlock(tsk->group_leader);
 
 	if (retval || resource != RLIMIT_CPU)
 		goto out;
@@ -1318,14 +1317,23 @@ SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim)
 	 * very long-standing error, and fixing it now risks breakage of
 	 * applications, so we live with it
 	 */
-	if (new_rlim.rlim_cur == RLIM_INFINITY)
+	if (new_rlim->rlim_cur == RLIM_INFINITY)
 		goto out;
 
-	update_rlimit_cpu(current, new_rlim.rlim_cur);
+	update_rlimit_cpu(tsk, new_rlim->rlim_cur);
 out:
 	return retval;
 }
 
+SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim)
+{
+	struct rlimit new_rlim;
+
+	if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
+		return -EFAULT;
+	return do_setrlimit(current, resource, &new_rlim);
+}
+
 /*
  * It would make sense to put struct rusage in the task_struct,
  * except that would make the task_struct be *really big*.  After
-- 
1.7.1