Re: [PATCH] pid: change task_struct::pid to read-only
On 12/16, Richard Guy Briggs wrote:
task->pid is only ever assigned once (well ok, twice). For system health and
secure logging confidence, make it const to make it much more intentional when
it is being changed.
Hmm. I am a bit suprized you decided to constify task->pid, but OK.
And we can do the same with task->signal, this can actually help to generate
a better code, probably.
if (!thread_group_leader(tsk)) {
struct task_struct *leader = tsk->group_leader;
+ /* tast_struct::pid is const pid_t, hence the ugly cast */
+ pid_t *pid_p = (pid_t*)&(tsk->pid);
sig->notify_count = -1; /* for exit_notify() */
for (;;) {
@@ -950,7 +952,7 @@ static int de_thread(struct task_struct *tsk)
* Note: The old leader also uses this pid until release_task
* is called. Odd but simple and correct.
*/
- tsk->pid = leader->pid;
+ *pid_p = leader->pid;
Well, imho this (and de_thread) looks a bit ugly. Perhaps we should add
something like
#define ASSIGN_CONST(l, r) (*(typeof(r) *)&(l) = (r))
into compiler.h ?
Oleg.