Implement prlimit64() system call.

Differential Revision:	https://reviews.freebsd.org/D1050
Reviewed by:	emaste, trasz

sys/amd64/linux32/linux32_dummy.c

@@ -133,8 +133,6 @@ DUMMY(perf_event_open);
 DUMMY(recvmmsg);
 DUMMY(fanotify_init);
 DUMMY(fanotify_mark);
-/* linux 2.6.36: */
-DUMMY(prlimit64);
 /* later: */
 DUMMY(name_to_handle_at);
 DUMMY(open_by_handle_at);

sys/amd64/linux32/syscalls.master

@@ -554,7 +554,10 @@
 338	AUE_NULL	STD	{ int linux_fanotify_init(void); }
 339	AUE_NULL	STD	{ int linux_fanotify_mark(void); }
 ; linux 2.6.36:
-340	AUE_NULL	STD	{ int linux_prlimit64(void); }
+340	AUE_NULL	STD	{ int linux_prlimit64(l_pid_t pid,	\
+				    l_uint resource,			\
+				    struct rlimit *new,			\
+				    struct rlimit *old); }
 ; later:
 341	AUE_NULL	STD	{ int linux_name_to_handle_at(void); }
 342	AUE_NULL	STD	{ int linux_open_by_handle_at(void); }

sys/compat/linux/linux_misc.c

@@ -2034,6 +2034,79 @@ linux_sched_setaffinity(struct thread *td,
 	return (sys_cpuset_setaffinity(td, &csa));
 }
 
+struct linux_rlimit64 {
+	uint64_t	rlim_cur;
+	uint64_t	rlim_max;
+};
+
+int
+linux_prlimit64(struct thread *td, struct linux_prlimit64_args *args)
+{
+	struct rlimit rlim, nrlim;
+	struct linux_rlimit64 lrlim;
+	struct proc *p;
+	u_int which;
+	int flags;
+	int error;
+
+#ifdef DEBUG
+	if (ldebug(prlimit64))
+		printf(ARGS(prlimit64, "%d, %d, %p, %p"), args->pid,
+		    args->resource, (void *)args->new, (void *)args->old);
+#endif
+
+	if (args->resource >= LINUX_RLIM_NLIMITS)
+		return (EINVAL);
+
+	which = linux_to_bsd_resource[args->resource];
+	if (which == -1)
+		return (EINVAL);
+
+	if (args->new != NULL) {
+		/*
+		 * Note. Unlike FreeBSD where rlim is signed 64-bit Linux
+		 * rlim is unsigned 64-bit. FreeBSD treats negative limits
+		 * as INFINITY so we do not need a conversion even.
+		 */
+		error = copyin(args->new, &nrlim, sizeof(nrlim));
+		if (error != 0)
+			return (error);
+	}
+
+	flags = PGET_HOLD | PGET_NOTWEXIT;
+	if (args->new != NULL)
+		flags |= PGET_CANDEBUG;
+	else
+		flags |= PGET_CANSEE;
+	error = pget(args->pid, flags, &p);
+	if (error != 0)
+		return (error);
+
+	if (args->old != NULL) {
+		PROC_LOCK(p);
+		lim_rlimit(p, which, &rlim);
+		PROC_UNLOCK(p);
+		if (rlim.rlim_cur == RLIM_INFINITY)
+			lrlim.rlim_cur = LINUX_RLIM_INFINITY;
+		else
+			lrlim.rlim_cur = rlim.rlim_cur;
+		if (rlim.rlim_max == RLIM_INFINITY)
+			lrlim.rlim_max = LINUX_RLIM_INFINITY;
+		else
+			lrlim.rlim_max = rlim.rlim_max;
+		error = copyout(&lrlim, args->old, sizeof(lrlim));
+		if (error != 0)
+			goto out;
+	}
+
+	if (args->new != NULL)
+		error = kern_proc_setrlimit(td, p, which, &nrlim);
+
+ out:
+	PRELE(p);
+	return (error);
+}
+
 int
 linux_sched_rr_get_interval(struct thread *td,
     struct linux_sched_rr_get_interval_args *uap)

sys/compat/linux/linux_misc.h

@@ -130,6 +130,7 @@ extern int stclohz;
 #define	LINUX_P_PID		1
 #define	LINUX_P_PGID		2
 
+#define	LINUX_RLIM_INFINITY	(~0UL)
 
 int linux_common_wait(struct thread *td, int pid, int *status,
 			int options, struct rusage *ru);

sys/i386/linux/linux_dummy.c

@@ -129,8 +129,6 @@ DUMMY(perf_event_open);
 DUMMY(recvmmsg);
 DUMMY(fanotify_init);
 DUMMY(fanotify_mark);
-/* linux 2.6.36: */
-DUMMY(prlimit64);
 /* later: */
 DUMMY(name_to_handle_at);
 DUMMY(open_by_handle_at);

sys/i386/linux/syscalls.master

@@ -562,7 +562,10 @@
 338	AUE_NULL	STD	{ int linux_fanotify_init(void); }
 339	AUE_NULL	STD	{ int linux_fanotify_mark(void); }
 ; linux 2.6.36:
-340	AUE_NULL	STD	{ int linux_prlimit64(void); }
+340	AUE_NULL	STD	{ int linux_prlimit64(l_pid_t pid,	\
+				    l_uint resource,			\
+				    struct rlimit *new,			\
+				    struct rlimit *old); }
 ; later:
 341	AUE_NULL	STD	{ int linux_name_to_handle_at(void); }
 342	AUE_NULL	STD	{ int linux_open_by_handle_at(void); }