RFC: [PATCH] Fix setpriority calling __task_priority() for processes instead of threads.

[Svante Signell]

Hi,

Attached is a patch for the call of __task_priority() in
sysdeps/mach/hurd/setpriority.c. According to setpriority(2) and POSIX the nice
value should be per-process not per-thread.
According to: http://pubs.opengroup.org/onlinepubs/009695399/functions/getpriori
ty.html
The nice value set with setpriority() shall be applied to the process. If the
process is multi-threaded, the nice value shall affect all system scope threads
in the process.

Unfortunately the call to __task_priority() is set with the change_threads
parameter true in gnumach/kern/task.c making a simple test program fail.
cat check_setpriority.c
#include <err.h>
#include <sys/time.h>
#include <sys/resource.h>

int main ()
{
  if (setpriority(PRIO_PROCESS, 0, -20) == -1)
    {
      warn("can't set priority");
      return -1;
    }

  return 0;
}

The attached patch changes this fixing the previous:
check_setpriority: can't set priority: Permission denied


Thanks!

sysdeps_mach_hurd_setpriority.c.diff
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