linux/kernel/time/itimer.c

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License cleanup: add SPDX GPL-2.0 license identifier to files with no license Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-01 14:07:57 +00:00
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 1992 Darren Senn
*/
/* These are all the functions necessary to implement itimers */
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/syscalls.h>
#include <linux/time.h>
#include <linux/sched/signal.h>
#include <linux/sched/cputime.h>
#include <linux/posix-timers.h>
#include <linux/hrtimer.h>
#include <trace/events/timer.h>
#include <linux/compat.h>
#include <linux/uaccess.h>
/**
* itimer_get_remtime - get remaining time for the timer
*
* @timer: the timer to read
*
* Returns the delta between the expiry time and now, which can be
* less than zero or 1usec for an pending expired timer
*/
static struct timespec64 itimer_get_remtime(struct hrtimer *timer)
{
ktime_t rem = __hrtimer_get_remaining(timer, true);
/*
* Racy but safe: if the itimer expires after the above
* hrtimer_get_remtime() call but before this condition
* then we return 0 - which is correct.
*/
if (hrtimer_active(timer)) {
if (rem <= 0)
rem = NSEC_PER_USEC;
} else
rem = 0;
return ktime_to_timespec64(rem);
}
static void get_cpu_itimer(struct task_struct *tsk, unsigned int clock_id,
struct itimerspec64 *const value)
{
u64 val, interval;
struct cpu_itimer *it = &tsk->signal->it[clock_id];
spin_lock_irq(&tsk->sighand->siglock);
val = it->expires;
interval = it->incr;
if (val) {
u64 t, samples[CPUCLOCK_MAX];
thread_group_sample_cputime(tsk, samples);
t = samples[clock_id];
if (val < t)
/* about to fire */
val = TICK_NSEC;
else
val -= t;
}
spin_unlock_irq(&tsk->sighand->siglock);
value->it_value = ns_to_timespec64(val);
value->it_interval = ns_to_timespec64(interval);
}
static int do_getitimer(int which, struct itimerspec64 *value)
{
struct task_struct *tsk = current;
switch (which) {
case ITIMER_REAL:
spin_lock_irq(&tsk->sighand->siglock);
value->it_value = itimer_get_remtime(&tsk->signal->real_timer);
value->it_interval =
ktime_to_timespec64(tsk->signal->it_real_incr);
spin_unlock_irq(&tsk->sighand->siglock);
break;
case ITIMER_VIRTUAL:
get_cpu_itimer(tsk, CPUCLOCK_VIRT, value);
break;
case ITIMER_PROF:
get_cpu_itimer(tsk, CPUCLOCK_PROF, value);
break;
default:
return(-EINVAL);
}
return 0;
}
static int put_itimerval(struct __kernel_old_itimerval __user *o,
const struct itimerspec64 *i)
{
struct __kernel_old_itimerval v;
v.it_interval.tv_sec = i->it_interval.tv_sec;
v.it_interval.tv_usec = i->it_interval.tv_nsec / NSEC_PER_USEC;
v.it_value.tv_sec = i->it_value.tv_sec;
v.it_value.tv_usec = i->it_value.tv_nsec / NSEC_PER_USEC;
return copy_to_user(o, &v, sizeof(struct __kernel_old_itimerval)) ? -EFAULT : 0;
}
SYSCALL_DEFINE2(getitimer, int, which, struct __kernel_old_itimerval __user *, value)
{
struct itimerspec64 get_buffer;
int error = do_getitimer(which, &get_buffer);
if (!error && put_itimerval(value, &get_buffer))
error = -EFAULT;
return error;
}
#if defined(CONFIG_COMPAT) || defined(CONFIG_ALPHA)
struct old_itimerval32 {
struct old_timeval32 it_interval;
struct old_timeval32 it_value;
};
static int put_old_itimerval32(struct old_itimerval32 __user *o,
const struct itimerspec64 *i)
{
struct old_itimerval32 v32;
v32.it_interval.tv_sec = i->it_interval.tv_sec;
v32.it_interval.tv_usec = i->it_interval.tv_nsec / NSEC_PER_USEC;
v32.it_value.tv_sec = i->it_value.tv_sec;
v32.it_value.tv_usec = i->it_value.tv_nsec / NSEC_PER_USEC;
return copy_to_user(o, &v32, sizeof(struct old_itimerval32)) ? -EFAULT : 0;
}
COMPAT_SYSCALL_DEFINE2(getitimer, int, which,
struct old_itimerval32 __user *, value)
{
struct itimerspec64 get_buffer;
int error = do_getitimer(which, &get_buffer);
if (!error && put_old_itimerval32(value, &get_buffer))
error = -EFAULT;
return error;
}
#endif
/*
* The timer is automagically restarted, when interval != 0
*/
enum hrtimer_restart it_real_fn(struct hrtimer *timer)
{
struct signal_struct *sig =
container_of(timer, struct signal_struct, real_timer);
struct pid *leader_pid = sig->pids[PIDTYPE_TGID];
trace_itimer_expire(ITIMER_REAL, leader_pid, 0);
kill_pid_info(SIGALRM, SEND_SIG_PRIV, leader_pid);
return HRTIMER_NORESTART;
}
static void set_cpu_itimer(struct task_struct *tsk, unsigned int clock_id,
const struct itimerspec64 *const value,
struct itimerspec64 *const ovalue)
{
u64 oval, nval, ointerval, ninterval;
struct cpu_itimer *it = &tsk->signal->it[clock_id];
nval = timespec64_to_ns(&value->it_value);
ninterval = timespec64_to_ns(&value->it_interval);
spin_lock_irq(&tsk->sighand->siglock);
oval = it->expires;
ointerval = it->incr;
if (oval || nval) {
if (nval > 0)
nval += TICK_NSEC;
set_process_cpu_timer(tsk, clock_id, &nval, &oval);
}
it->expires = nval;
it->incr = ninterval;
trace_itimer_state(clock_id == CPUCLOCK_VIRT ?
ITIMER_VIRTUAL : ITIMER_PROF, value, nval);
spin_unlock_irq(&tsk->sighand->siglock);
if (ovalue) {
ovalue->it_value = ns_to_timespec64(oval);
ovalue->it_interval = ns_to_timespec64(ointerval);
}
}
/*
* Returns true if the timeval is in canonical form
*/
#define timeval_valid(t) \
(((t)->tv_sec >= 0) && (((unsigned long) (t)->tv_usec) < USEC_PER_SEC))
static int do_setitimer(int which, struct itimerspec64 *value,
struct itimerspec64 *ovalue)
{
struct task_struct *tsk = current;
struct hrtimer *timer;
ktime_t expires;
switch (which) {
case ITIMER_REAL:
again:
spin_lock_irq(&tsk->sighand->siglock);
timer = &tsk->signal->real_timer;
if (ovalue) {
ovalue->it_value = itimer_get_remtime(timer);
ovalue->it_interval
= ktime_to_timespec64(tsk->signal->it_real_incr);
}
/* We are sharing ->siglock with it_real_fn() */
if (hrtimer_try_to_cancel(timer) < 0) {
spin_unlock_irq(&tsk->sighand->siglock);
hrtimer_cancel_wait_running(timer);
goto again;
}
expires = timespec64_to_ktime(value->it_value);
if (expires != 0) {
tsk->signal->it_real_incr =
timespec64_to_ktime(value->it_interval);
hrtimer_start(timer, expires, HRTIMER_MODE_REL);
} else
tsk->signal->it_real_incr = 0;
trace_itimer_state(ITIMER_REAL, value, 0);
spin_unlock_irq(&tsk->sighand->siglock);
break;
case ITIMER_VIRTUAL:
set_cpu_itimer(tsk, CPUCLOCK_VIRT, value, ovalue);
break;
case ITIMER_PROF:
set_cpu_itimer(tsk, CPUCLOCK_PROF, value, ovalue);
break;
default:
return -EINVAL;
}
return 0;
}
#ifdef CONFIG_SECURITY_SELINUX
void clear_itimer(void)
{
struct itimerspec64 v = {};
int i;
for (i = 0; i < 3; i++)
do_setitimer(i, &v, NULL);
}
#endif
#ifdef __ARCH_WANT_SYS_ALARM
/**
* alarm_setitimer - set alarm in seconds
*
* @seconds: number of seconds until alarm
* 0 disables the alarm
*
* Returns the remaining time in seconds of a pending timer or 0 when
* the timer is not active.
*
* On 32 bit machines the seconds value is limited to (INT_MAX/2) to avoid
* negative timeval settings which would cause immediate expiry.
*/
static unsigned int alarm_setitimer(unsigned int seconds)
{
struct itimerspec64 it_new, it_old;
#if BITS_PER_LONG < 64
if (seconds > INT_MAX)
seconds = INT_MAX;
#endif
it_new.it_value.tv_sec = seconds;
it_new.it_value.tv_nsec = 0;
it_new.it_interval.tv_sec = it_new.it_interval.tv_nsec = 0;
do_setitimer(ITIMER_REAL, &it_new, &it_old);
/*
* We can't return 0 if we have an alarm pending ... And we'd
* better return too much than too little anyway
*/
if ((!it_old.it_value.tv_sec && it_old.it_value.tv_nsec) ||
it_old.it_value.tv_nsec >= (NSEC_PER_SEC / 2))
it_old.it_value.tv_sec++;
return it_old.it_value.tv_sec;
}
/*
* For backwards compatibility? This can be done in libc so Alpha
* and all newer ports shouldn't need it.
*/
SYSCALL_DEFINE1(alarm, unsigned int, seconds)
{
return alarm_setitimer(seconds);
}
#endif
static int get_itimerval(struct itimerspec64 *o, const struct __kernel_old_itimerval __user *i)
{
struct __kernel_old_itimerval v;
if (copy_from_user(&v, i, sizeof(struct __kernel_old_itimerval)))
return -EFAULT;
/* Validate the timevals in value. */
if (!timeval_valid(&v.it_value) ||
!timeval_valid(&v.it_interval))
return -EINVAL;
o->it_interval.tv_sec = v.it_interval.tv_sec;
o->it_interval.tv_nsec = v.it_interval.tv_usec * NSEC_PER_USEC;
o->it_value.tv_sec = v.it_value.tv_sec;
o->it_value.tv_nsec = v.it_value.tv_usec * NSEC_PER_USEC;
return 0;
}
SYSCALL_DEFINE3(setitimer, int, which, struct __kernel_old_itimerval __user *, value,
struct __kernel_old_itimerval __user *, ovalue)
{
struct itimerspec64 set_buffer, get_buffer;
int error;
if (value) {
error = get_itimerval(&set_buffer, value);
if (error)
return error;
} else {
memset(&set_buffer, 0, sizeof(set_buffer));
printk_once(KERN_WARNING "%s calls setitimer() with new_value NULL pointer."
" Misfeature support will be removed\n",
current->comm);
}
error = do_setitimer(which, &set_buffer, ovalue ? &get_buffer : NULL);
if (error || !ovalue)
return error;
if (put_itimerval(ovalue, &get_buffer))
return -EFAULT;
return 0;
}
#if defined(CONFIG_COMPAT) || defined(CONFIG_ALPHA)
static int get_old_itimerval32(struct itimerspec64 *o, const struct old_itimerval32 __user *i)
{
struct old_itimerval32 v32;
if (copy_from_user(&v32, i, sizeof(struct old_itimerval32)))
return -EFAULT;
/* Validate the timevals in value. */
if (!timeval_valid(&v32.it_value) ||
!timeval_valid(&v32.it_interval))
return -EINVAL;
o->it_interval.tv_sec = v32.it_interval.tv_sec;
o->it_interval.tv_nsec = v32.it_interval.tv_usec * NSEC_PER_USEC;
o->it_value.tv_sec = v32.it_value.tv_sec;
o->it_value.tv_nsec = v32.it_value.tv_usec * NSEC_PER_USEC;
return 0;
}
COMPAT_SYSCALL_DEFINE3(setitimer, int, which,
struct old_itimerval32 __user *, value,
struct old_itimerval32 __user *, ovalue)
{
struct itimerspec64 set_buffer, get_buffer;
int error;
if (value) {
error = get_old_itimerval32(&set_buffer, value);
if (error)
return error;
} else {
memset(&set_buffer, 0, sizeof(set_buffer));
printk_once(KERN_WARNING "%s calls setitimer() with new_value NULL pointer."
" Misfeature support will be removed\n",
current->comm);
}
error = do_setitimer(which, &set_buffer, ovalue ? &get_buffer : NULL);
if (error || !ovalue)
return error;
if (put_old_itimerval32(ovalue, &get_buffer))
return -EFAULT;
return 0;
}
#endif