From 1d8659dce1cb63d059a9875625d7b483d0fb7dcc Mon Sep 17 00:00:00 2001
From: Matt Mackall <mpm@selenic.com>
Date: Sun, 1 May 2005 08:59:00 -0700
Subject: [PATCH] --- yaml --- r: 707 b: refs/heads/master c:
 e43379f10b42194b8a6e1de342cfb44463c0f6da h: refs/heads/master i:   705:
 ff78abb8ba679821557f335a4aeef549e14eb93f   703:
 ba53a08f499bd8ef777207c4f2fa1b5b563ff648 v: v3

---
 [refs]                               |  2 +-
 trunk/include/asm-generic/resource.h |  7 ++++++-
 trunk/include/linux/sched.h          |  1 +
 trunk/kernel/sched.c                 | 25 +++++++++++++++++++------
 trunk/kernel/sys.c                   |  2 +-
 5 files changed, 28 insertions(+), 9 deletions(-)

diff --git a/[refs] b/[refs]
index 322dd5d231ec..53b6328ffc6d 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 9fc1427a01a9df3605e219c6de0c59c4639209a1
+refs/heads/master: e43379f10b42194b8a6e1de342cfb44463c0f6da
diff --git a/trunk/include/asm-generic/resource.h b/trunk/include/asm-generic/resource.h
index b1fcda9eac23..cfe3692b23e5 100644
--- a/trunk/include/asm-generic/resource.h
+++ b/trunk/include/asm-generic/resource.h
@@ -41,8 +41,11 @@
 #define RLIMIT_LOCKS		10	/* maximum file locks held */
 #define RLIMIT_SIGPENDING	11	/* max number of pending signals */
 #define RLIMIT_MSGQUEUE		12	/* maximum bytes in POSIX mqueues */
+#define RLIMIT_NICE		13	/* max nice prio allowed to raise to
+					   0-39 for nice level 19 .. -20 */
+#define RLIMIT_RTPRIO		14	/* maximum realtime priority */
 
-#define RLIM_NLIMITS		13
+#define RLIM_NLIMITS		15
 
 /*
  * SuS says limits have to be unsigned.
@@ -81,6 +84,8 @@
 	[RLIMIT_LOCKS]		= {  RLIM_INFINITY,  RLIM_INFINITY },	\
 	[RLIMIT_SIGPENDING]	= { 		0,	       0 },	\
 	[RLIMIT_MSGQUEUE]	= {   MQ_BYTES_MAX,   MQ_BYTES_MAX },	\
+	[RLIMIT_NICE]		= { 0, 0 },				\
+	[RLIMIT_RTPRIO]		= { 0, 0 },				\
 }
 
 #endif	/* __KERNEL__ */
diff --git a/trunk/include/linux/sched.h b/trunk/include/linux/sched.h
index 1cced971232c..8960f99ea128 100644
--- a/trunk/include/linux/sched.h
+++ b/trunk/include/linux/sched.h
@@ -845,6 +845,7 @@ extern void sched_idle_next(void);
 extern void set_user_nice(task_t *p, long nice);
 extern int task_prio(const task_t *p);
 extern int task_nice(const task_t *p);
+extern int can_nice(const task_t *p, const int nice);
 extern int task_curr(const task_t *p);
 extern int idle_cpu(int cpu);
 extern int sched_setscheduler(struct task_struct *, int, struct sched_param *);
diff --git a/trunk/kernel/sched.c b/trunk/kernel/sched.c
index 9bb7489ee645..5dadcc6df7dd 100644
--- a/trunk/kernel/sched.c
+++ b/trunk/kernel/sched.c
@@ -3223,6 +3223,19 @@ void set_user_nice(task_t *p, long nice)
 
 EXPORT_SYMBOL(set_user_nice);
 
+/*
+ * can_nice - check if a task can reduce its nice value
+ * @p: task
+ * @nice: nice value
+ */
+int can_nice(const task_t *p, const int nice)
+{
+	/* convert nice value [19,-20] to rlimit style value [0,39] */
+	int nice_rlim = 19 - nice;
+	return (nice_rlim <= p->signal->rlim[RLIMIT_NICE].rlim_cur ||
+		capable(CAP_SYS_NICE));
+}
+
 #ifdef __ARCH_WANT_SYS_NICE
 
 /*
@@ -3242,12 +3255,8 @@ asmlinkage long sys_nice(int increment)
 	 * We don't have to worry. Conceptually one call occurs first
 	 * and we have a single winner.
 	 */
-	if (increment < 0) {
-		if (!capable(CAP_SYS_NICE))
-			return -EPERM;
-		if (increment < -40)
-			increment = -40;
-	}
+	if (increment < -40)
+		increment = -40;
 	if (increment > 40)
 		increment = 40;
 
@@ -3257,6 +3266,9 @@ asmlinkage long sys_nice(int increment)
 	if (nice > 19)
 		nice = 19;
 
+	if (increment < 0 && !can_nice(current, nice))
+		return -EPERM;
+
 	retval = security_task_setnice(current, nice);
 	if (retval)
 		return retval;
@@ -3372,6 +3384,7 @@ int sched_setscheduler(struct task_struct *p, int policy, struct sched_param *pa
 		return -EINVAL;
 
 	if ((policy == SCHED_FIFO || policy == SCHED_RR) &&
+	    param->sched_priority > p->signal->rlim[RLIMIT_RTPRIO].rlim_cur &&
 	    !capable(CAP_SYS_NICE))
 		return -EPERM;
 	if ((current->euid != p->euid) && (current->euid != p->uid) &&
diff --git a/trunk/kernel/sys.c b/trunk/kernel/sys.c
index df2ddcc6863b..7f43d6e62c7a 100644
--- a/trunk/kernel/sys.c
+++ b/trunk/kernel/sys.c
@@ -227,7 +227,7 @@ static int set_one_prio(struct task_struct *p, int niceval, int error)
 		error = -EPERM;
 		goto out;
 	}
-	if (niceval < task_nice(p) && !capable(CAP_SYS_NICE)) {
+	if (niceval < task_nice(p) && !can_nice(p, niceval)) {
 		error = -EACCES;
 		goto out;
 	}