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Date: Sun, 18 Jun 2017 23:45:14 -0700
From: Deepa Dinamani <deepa.kernel@...il.com>
To: tglx@...utronix.de, viro@...iv.linux.org.uk,
linux-kernel@...r.kernel.org
Cc: john.stultz@...aro.org, nicolas.pitre@...aro.org, arnd@...db.de,
y2038@...ts.linaro.org, linux-fsdevel@...r.kernel.org
Subject: [PATCH 7/8] posix_clocks: Use get_itimerspec64() and put_itimerspec64()
Usage of these apis and their compat versions makes
the syscalls: timer_settime and timer_gettime and their
compat implementations simpler.
This patch also serves as a preparatory patch for changing
syscalls to use new time_t data types to support the
y2038 effort by isolating the processing of user pointers
through these apis.
Signed-off-by: Deepa Dinamani <deepa.kernel@...il.com>
---
kernel/time/posix-timers.c | 138 +++++++++++++++++++++++++++------------------
1 file changed, 84 insertions(+), 54 deletions(-)
diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c
index 58ed4e759485..c642c6a959ff 100644
--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -690,32 +690,54 @@ void common_timer_get(struct k_itimer *timr, struct itimerspec64 *cur_setting)
}
}
+/* common set of checks before we invoke timer_gettime and
+ * timer_settime apis.
+ */
+static int common_prep_timer(const struct k_clock **kc_ptr,
+ struct k_itimer **timr_ptr,
+ timer_t timer_id,
+ long *flags,
+ struct itimerspec64 *it)
+{
+ int error = 0;
+ const struct k_clock *kc;
+ struct k_itimer *timr;
+
+ if (it && !itimerspec64_valid(it))
+ return -EINVAL;
+
+ *timr_ptr = timr = lock_timer(timer_id, flags);
+ if (!timr)
+ return -EINVAL;
+
+ *kc_ptr = kc = timr->kclock;
+
+ if (WARN_ON_ONCE(!kc || !kc->timer_set))
+ error = -EINVAL;
+
+ return error;
+}
+
/* Get the time remaining on a POSIX.1b interval timer. */
SYSCALL_DEFINE2(timer_gettime, timer_t, timer_id,
struct itimerspec __user *, setting)
{
- struct itimerspec64 cur_setting64;
- struct itimerspec cur_setting;
+ struct itimerspec64 cur_setting;
struct k_itimer *timr;
const struct k_clock *kc;
unsigned long flags;
int ret = 0;
- timr = lock_timer(timer_id, &flags);
- if (!timr)
- return -EINVAL;
-
- memset(&cur_setting64, 0, sizeof(cur_setting64));
- kc = timr->kclock;
- if (WARN_ON_ONCE(!kc || !kc->timer_get))
- ret = -EINVAL;
+ memset(&cur_setting, 0, sizeof(cur_setting));
+ ret = common_prep_timer(&kc, &timr, timer_id, &flags, NULL);
+ if (ret)
+ return ret;
else
- kc->timer_get(timr, &cur_setting64);
+ kc->timer_get(timr, &cur_setting);
unlock_timer(timr, flags);
- cur_setting = itimerspec64_to_itimerspec(&cur_setting64);
- if (!ret && copy_to_user(setting, &cur_setting, sizeof (cur_setting)))
+ if (!ret && put_itimerspec64(&cur_setting, setting))
return -EFAULT;
return ret;
@@ -813,9 +835,8 @@ SYSCALL_DEFINE4(timer_settime, timer_t, timer_id, int, flags,
const struct itimerspec __user *, new_setting,
struct itimerspec __user *, old_setting)
{
- struct itimerspec64 new_spec64, old_spec64;
- struct itimerspec64 *rtn = old_setting ? &old_spec64 : NULL;
- struct itimerspec new_spec, old_spec;
+ struct itimerspec64 new_spec, old_spec;
+ struct itimerspec64 *rtn = old_setting ? &old_spec : NULL;
struct k_itimer *timr;
unsigned long flag;
const struct k_clock *kc;
@@ -824,23 +845,15 @@ SYSCALL_DEFINE4(timer_settime, timer_t, timer_id, int, flags,
if (!new_setting)
return -EINVAL;
- if (copy_from_user(&new_spec, new_setting, sizeof (new_spec)))
- return -EFAULT;
- new_spec64 = itimerspec_to_itimerspec64(&new_spec);
+ error = get_itimerspec64(&new_spec, new_setting);
+ if (error)
+ return error;
- if (!timespec64_valid(&new_spec64.it_interval) ||
- !timespec64_valid(&new_spec64.it_value))
- return -EINVAL;
retry:
- timr = lock_timer(timer_id, &flag);
- if (!timr)
- return -EINVAL;
+ error = common_prep_timer(&kc, &timr, timer_id, &flag, &new_spec);
- kc = timr->kclock;
- if (WARN_ON_ONCE(!kc || !kc->timer_set))
- error = -EINVAL;
- else
- error = kc->timer_set(timr, flags, &new_spec64, rtn);
+ if (!error)
+ error = kc->timer_set(timr, flags, &new_spec, rtn);
unlock_timer(timr, flag);
if (error == TIMER_RETRY) {
@@ -848,9 +861,8 @@ SYSCALL_DEFINE4(timer_settime, timer_t, timer_id, int, flags,
goto retry;
}
- old_spec = itimerspec64_to_itimerspec(&old_spec64);
if (old_setting && !error &&
- copy_to_user(old_setting, &old_spec, sizeof (old_spec)))
+ put_itimerspec64(&old_spec, old_setting))
error = -EFAULT;
return error;
@@ -1220,21 +1232,33 @@ COMPAT_SYSCALL_DEFINE4(timer_settime, timer_t, timer_id, int, flags,
struct compat_itimerspec __user *, new,
struct compat_itimerspec __user *, old)
{
+ struct itimerspec64 newts, oldts;
+ struct itimerspec64 *rtn = old ? &oldts : NULL;
+ struct k_itimer *timr;
+ unsigned long flag;
+ const struct k_clock *kc;
long err;
- mm_segment_t oldfs;
- struct itimerspec newts, oldts;
if (!new)
return -EINVAL;
- if (get_compat_itimerspec(&newts, new))
- return -EFAULT;
- oldfs = get_fs();
- set_fs(KERNEL_DS);
- err = sys_timer_settime(timer_id, flags,
- (struct itimerspec __user *) &newts,
- (struct itimerspec __user *) &oldts);
- set_fs(oldfs);
- if (!err && old && put_compat_itimerspec(old, &oldts))
+ err = get_compat_itimerspec64(&newts, new);
+ if (err)
+ return err;
+
+retry:
+
+ err = common_prep_timer(&kc, &timr, timer_id, &flag, &newts);
+
+ if (!err)
+ err = kc->timer_set(timr, flags, &newts, rtn);
+
+ unlock_timer(timr, flag);
+ if (err == TIMER_RETRY) {
+ rtn = NULL; // We already got the old time...
+ goto retry;
+ }
+
+ if (!err && old && put_compat_itimerspec64(&oldts, old))
return -EFAULT;
return err;
}
@@ -1242,18 +1266,24 @@ COMPAT_SYSCALL_DEFINE4(timer_settime, timer_t, timer_id, int, flags,
COMPAT_SYSCALL_DEFINE2(timer_gettime, timer_t, timer_id,
struct compat_itimerspec __user *, setting)
{
- long err;
- mm_segment_t oldfs;
- struct itimerspec ts;
-
- oldfs = get_fs();
- set_fs(KERNEL_DS);
- err = sys_timer_gettime(timer_id,
- (struct itimerspec __user *) &ts);
- set_fs(oldfs);
- if (!err && put_compat_itimerspec(setting, &ts))
+ struct itimerspec64 ts;
+ struct k_itimer *timr;
+ const struct k_clock *kc;
+ unsigned long flags;
+ int ret = 0;
+
+ memset(&ts, 0, sizeof(ts));
+ ret = common_prep_timer(&kc, &timr, timer_id, &flags, NULL);
+ if (ret)
+ return ret;
+
+ kc->timer_get(timr, &ts);
+
+ unlock_timer(timr, flags);
+
+ if (!ret && put_compat_itimerspec64(&ts, setting))
return -EFAULT;
- return err;
+ return ret;
}
COMPAT_SYSCALL_DEFINE2(clock_settime, clockid_t, which_clock,
--
2.11.0
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