| Date | Thu, 22 Aug 2019 00:33:57 +0200 | From | Frederic Weisbecker <> | Subject | Re: [patch V2 01/38] posix-cpu-timers: Provide task validation functions |
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On Wed, Aug 21, 2019 at 09:08:48PM +0200, Thomas Gleixner wrote: > The code contains three slightly different copies of validating whether a > given clock resolves to a valid task and whether the current caller has > permissions to access it. > > Create central functions. Replace check_clock() as a first step and rename > it to something sensible. > > Signed-off-by: Thomas Gleixner <tglx@linutronix.de> > --- > kernel/time/posix-cpu-timers.c | 65 +++++++++++++++++++++++++++-------------- > 1 file changed, 44 insertions(+), 21 deletions(-) > > --- a/kernel/time/posix-cpu-timers.c > +++ b/kernel/time/posix-cpu-timers.c > @@ -35,27 +35,52 @@ void update_rlimit_cpu(struct task_struc > spin_unlock_irq(&task->sighand->siglock); > } > > -static int check_clock(const clockid_t which_clock) > +/* > + * Functions for validating access to tasks. > + */ > +static struct task_struct *lookup_task(const pid_t pid, bool thread) > { > - int error = 0; > struct task_struct *p; > - const pid_t pid = CPUCLOCK_PID(which_clock); > > - if (CPUCLOCK_WHICH(which_clock) >= CPUCLOCK_MAX) > - return -EINVAL; > + if (!pid) > + return thread ? current : current->group_leader; > > - if (pid == 0) > - return 0; > + p = find_task_by_vpid(pid); > + if (!p || p == current) > + return p;
What if (p == current && !thread && !has_group_leader_pid(p)) ?
> + if (thread) > + return same_thread_group(p, current) ? p : NULL; > + if (p == current) > + return p;
You already checked that above.
> + return has_group_leader_pid(p) ? p : NULL; > +}
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