posix-timers: Make them configurable

[mirror_ubuntu-zesty-kernel.git] / kernel / time / posix-stubs.c

diff --git a/kernel/time/posix-stubs.c b/kernel/time/posix-stubs.c
new file mode 100644 (file)
index 0000000..cd6716e
--- /dev/null
+++ b/kernel/time/posix-stubs.c
@@ -0,0 +1,123 @@
+/*
+ * Dummy stubs used when CONFIG_POSIX_TIMERS=n
+ *
+ * Created by:  Nicolas Pitre, July 2016
+ * Copyright:   (C) 2016 Linaro Limited
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/linkage.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/errno.h>
+#include <linux/syscalls.h>
+#include <linux/ktime.h>
+#include <linux/timekeeping.h>
+#include <linux/posix-timers.h>
+
+asmlinkage long sys_ni_posix_timers(void)
+{
+       pr_err_once("process %d (%s) attempted a POSIX timer syscall "
+                   "while CONFIG_POSIX_TIMERS is not set\n",
+                   current->pid, current->comm);
+       return -ENOSYS;
+}
+
+#define SYS_NI(name)  SYSCALL_ALIAS(sys_##name, sys_ni_posix_timers)
+
+SYS_NI(timer_create);
+SYS_NI(timer_gettime);
+SYS_NI(timer_getoverrun);
+SYS_NI(timer_settime);
+SYS_NI(timer_delete);
+SYS_NI(clock_adjtime);
+SYS_NI(getitimer);
+SYS_NI(setitimer);
+#ifdef __ARCH_WANT_SYS_ALARM
+SYS_NI(alarm);
+#endif
+
+/*
+ * We preserve minimal support for CLOCK_REALTIME and CLOCK_MONOTONIC
+ * as it is easy to remain compatible with little code. CLOCK_BOOTTIME
+ * is also included for convenience as at least systemd uses it.
+ */
+
+SYSCALL_DEFINE2(clock_settime, const clockid_t, which_clock,
+               const struct timespec __user *, tp)
+{
+       struct timespec new_tp;
+
+       if (which_clock != CLOCK_REALTIME)
+               return -EINVAL;
+       if (copy_from_user(&new_tp, tp, sizeof (*tp)))
+               return -EFAULT;
+       return do_sys_settimeofday(&new_tp, NULL);
+}
+
+SYSCALL_DEFINE2(clock_gettime, const clockid_t, which_clock,
+               struct timespec __user *,tp)
+{
+       struct timespec kernel_tp;
+
+       switch (which_clock) {
+       case CLOCK_REALTIME: ktime_get_real_ts(&kernel_tp); break;
+       case CLOCK_MONOTONIC: ktime_get_ts(&kernel_tp); break;
+       case CLOCK_BOOTTIME: get_monotonic_boottime(&kernel_tp); break;
+       default: return -EINVAL;
+       }
+       if (copy_to_user(tp, &kernel_tp, sizeof (kernel_tp)))
+               return -EFAULT;
+       return 0;
+}
+
+SYSCALL_DEFINE2(clock_getres, const clockid_t, which_clock, struct timespec __user *, tp)
+{
+       struct timespec rtn_tp = {
+               .tv_sec = 0,
+               .tv_nsec = hrtimer_resolution,
+       };
+
+       switch (which_clock) {
+       case CLOCK_REALTIME:
+       case CLOCK_MONOTONIC:
+       case CLOCK_BOOTTIME:
+               if (copy_to_user(tp, &rtn_tp, sizeof(rtn_tp)))
+                       return -EFAULT;
+               return 0;
+       default:
+               return -EINVAL;
+       }
+}
+
+SYSCALL_DEFINE4(clock_nanosleep, const clockid_t, which_clock, int, flags,
+               const struct timespec __user *, rqtp,
+               struct timespec __user *, rmtp)
+{
+       struct timespec t;
+
+       switch (which_clock) {
+       case CLOCK_REALTIME:
+       case CLOCK_MONOTONIC:
+       case CLOCK_BOOTTIME:
+               if (copy_from_user(&t, rqtp, sizeof (struct timespec)))
+                       return -EFAULT;
+               if (!timespec_valid(&t))
+                       return -EINVAL;
+               return hrtimer_nanosleep(&t, rmtp, flags & TIMER_ABSTIME ?
+                                        HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
+                                        which_clock);
+       default:
+               return -EINVAL;
+       }
+}
+
+#ifdef CONFIG_COMPAT
+long clock_nanosleep_restart(struct restart_block *restart_block)
+{
+       return hrtimer_nanosleep_restart(restart_block);
+}
+#endif