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signal: introduce do_sigtimedwait() to factor out compat/native code

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Factor out the common code in sys_rt_sigtimedwait/compat_sys_rt_sigtimedwait
to the new helper, do_sigtimedwait().

Add the comment to document the extra tick we add to timespec_to_jiffies(ts),
thanks to Linus who explained this to me.

Perhaps it would be better to move compat_sys_rt_sigtimedwait() into
signal.c under CONFIG_COMPAT, then we can make do_sigtimedwait() static.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Matt Fleming <matt.fleming@linux.intel.com>
This commit is contained in:
Oleg Nesterov 2011-04-27 21:44:14 +02:00
parent fe0faa005d
commit 943df1485a
3 changed files with 73 additions and 78 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/linux/signal.h
View File

@ -242,6 +242,8 @@ extern int __group_send_sig_info(int, struct siginfo *, struct task_struct *);
extern long do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig,
siginfo_t *info);
extern long do_sigpending(void __user *, unsigned long);
extern int do_sigtimedwait(const sigset_t *, siginfo_t *,
const struct timespec *);
extern int sigprocmask(int, sigset_t *, sigset_t *);
extern void set_current_blocked(const sigset_t *);
extern int show_unhandled_signals;

39
kernel/compat.c
View File

@ -890,10 +890,9 @@ compat_sys_rt_sigtimedwait (compat_sigset_t __user *uthese,
{
compat_sigset_t s32;
sigset_t s;
int sig;
struct timespec t;
siginfo_t info;
long ret, timeout;
long ret;
if (sigsetsize != sizeof(sigset_t))
return -EINVAL;
@ -901,45 +900,19 @@ compat_sys_rt_sigtimedwait (compat_sigset_t __user *uthese,
if (copy_from_user(&s32, uthese, sizeof(compat_sigset_t)))
return -EFAULT;
sigset_from_compat(&s, &s32);
sigdelsetmask(&s,sigmask(SIGKILL)|sigmask(SIGSTOP));
signotset(&s);
timeout = MAX_SCHEDULE_TIMEOUT;
if (uts) {
if (get_compat_timespec (&t, uts))
if (get_compat_timespec(&t, uts))
return -EFAULT;
if (!timespec_valid(&t))
return -EINVAL;
timeout = timespec_to_jiffies(&t) + (t.tv_sec || t.tv_nsec);
}
spin_lock_irq(&current->sighand->siglock);
sig = dequeue_signal(current, &s, &info);
if (!sig && timeout) {
current->real_blocked = current->blocked;
sigandsets(&current->blocked, &current->blocked, &s);
recalc_sigpending();
spin_unlock_irq(&current->sighand->siglock);
ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);
timeout = schedule_timeout_interruptible(timeout);
spin_lock_irq(&current->sighand->siglock);
sig = dequeue_signal(current, &s, &info);
current->blocked = current->real_blocked;
siginitset(&current->real_blocked, 0);
recalc_sigpending();
if (ret > 0 && uinfo) {
if (copy_siginfo_to_user32(uinfo, &info))
ret = -EFAULT;
}
spin_unlock_irq(&current->sighand->siglock);
if (sig) {
ret = sig;
if (uinfo) {
if (copy_siginfo_to_user32(uinfo, &info))
ret = -EFAULT;
}
} else {
ret = timeout?-EINTR:-EAGAIN;
}
return ret;
}

110
kernel/signal.c
View File

@ -2503,6 +2503,66 @@ int copy_siginfo_to_user(siginfo_t __user *to, siginfo_t *from)
#endif
/**
* do_sigtimedwait - wait for queued signals specified in @which
* @which: queued signals to wait for
* @info: if non-null, the signal's siginfo is returned here
* @ts: upper bound on process time suspension
*/
int do_sigtimedwait(const sigset_t *which, siginfo_t *info,
const struct timespec *ts)
{
struct task_struct *tsk = current;
long timeout = MAX_SCHEDULE_TIMEOUT;
sigset_t mask = *which;
int sig;
if (ts) {
if (!timespec_valid(ts))
return -EINVAL;
timeout = timespec_to_jiffies(ts);
/*
* We can be close to the next tick, add another one
* to ensure we will wait at least the time asked for.
*/
if (ts->tv_sec || ts->tv_nsec)
timeout++;
}
/*
* Invert the set of allowed signals to get those we want to block.
*/
sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP));
signotset(&mask);
spin_lock_irq(&tsk->sighand->siglock);
sig = dequeue_signal(tsk, &mask, info);
if (!sig && timeout) {
/*
* None ready, temporarily unblock those we're interested
* while we are sleeping in so that we'll be awakened when
* they arrive.
*/
tsk->real_blocked = tsk->blocked;
sigandsets(&tsk->blocked, &tsk->blocked, &mask);
recalc_sigpending();
spin_unlock_irq(&tsk->sighand->siglock);
timeout = schedule_timeout_interruptible(timeout);
spin_lock_irq(&tsk->sighand->siglock);
sig = dequeue_signal(tsk, &mask, info);
tsk->blocked = tsk->real_blocked;
siginitset(&tsk->real_blocked, 0);
recalc_sigpending();
}
spin_unlock_irq(&tsk->sighand->siglock);
if (sig)
return sig;
return timeout ? -EINTR : -EAGAIN;
}
/**
* sys_rt_sigtimedwait - synchronously wait for queued signals specified
* in @uthese
@ -2515,11 +2575,10 @@ SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
siginfo_t __user *, uinfo, const struct timespec __user *, uts,
size_t, sigsetsize)
{
int ret, sig;
sigset_t these;
struct timespec ts;
siginfo_t info;
long timeout;
int ret;
/* XXX: Don't preclude handling different sized sigset_t's. */
if (sigsetsize != sizeof(sigset_t))
@ -2528,55 +2587,16 @@ SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
if (copy_from_user(&these, uthese, sizeof(these)))
return -EFAULT;
/*
* Invert the set of allowed signals to get those we
* want to block.
*/
sigdelsetmask(&these, sigmask(SIGKILL)|sigmask(SIGSTOP));
signotset(&these);
timeout = MAX_SCHEDULE_TIMEOUT;
if (uts) {
if (copy_from_user(&ts, uts, sizeof(ts)))
return -EFAULT;
if (!timespec_valid(&ts))
return -EINVAL;
timeout = timespec_to_jiffies(&ts) + (ts.tv_sec || ts.tv_nsec);
}
spin_lock_irq(&current->sighand->siglock);
sig = dequeue_signal(current, &these, &info);
if (!sig && timeout) {
/*
* None ready -- temporarily unblock those we're
* interested while we are sleeping in so that we'll
* be awakened when they arrive.
*/
current->real_blocked = current->blocked;
sigandsets(&current->blocked, &current->blocked, &these);
recalc_sigpending();
spin_unlock_irq(&current->sighand->siglock);
ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
timeout = schedule_timeout_interruptible(timeout);
spin_lock_irq(&current->sighand->siglock);
sig = dequeue_signal(current, &these, &info);
current->blocked = current->real_blocked;
siginitset(&current->real_blocked, 0);
recalc_sigpending();
}
spin_unlock_irq(&current->sighand->siglock);
if (sig) {
ret = sig;
if (uinfo) {
if (copy_siginfo_to_user(uinfo, &info))
ret = -EFAULT;
}
} else {
ret = -EAGAIN;
if (timeout)
ret = -EINTR;
if (ret > 0 && uinfo) {
if (copy_siginfo_to_user(uinfo, &info))
ret = -EFAULT;
}
return ret;