FreeChainXenon/newlib-cygwin
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Cygwin: setpriority, sched_setparam: fail if Windows sets a lower priority

Browse source 
Windows silently sets a lower priority than requested if the new priority
requires administrator privileges.  Revert to previous priority and fail
with EACCES or EPERM in this case.

Signed-off-by: Christian Franke <christian.franke@t-online.de>
This commit is contained in:
Christian Franke 2024-11-27 10:26:38 +01:00 • committed by Corinna Vinschen
parent 46d1e63c76
commit 153b51ee08
5 changed files with 38 additions and 3 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

1
winsup/cygwin/local_includes/miscfuncs.h
View file

@ -46,6 +46,7 @@ is_alt_numpad_event (PINPUT_RECORD pirec)
int winprio_to_nice (DWORD);
DWORD nice_to_winprio (int &);
bool set_and_check_winprio (HANDLE proc, DWORD prio);
bool create_pipe (PHANDLE, PHANDLE, LPSECURITY_ATTRIBUTES, DWORD);

29
winsup/cygwin/miscfuncs.cc
View file

@ -183,6 +183,35 @@ nice_to_winprio (int &nice)
return prio;
}
/* Set Win32 priority or return false on failure. Also return
false and revert to the original priority if a different (lower)
priority is set instead. */
bool
set_and_check_winprio (HANDLE proc, DWORD prio)
{
DWORD prev_prio = GetPriorityClass (proc);
if (prev_prio == prio)
return true;
if (!SetPriorityClass (proc, prio))
return false;
/* Windows silently sets a lower priority (HIGH_PRIORITY_CLASS) if
the new priority (REALTIME_PRIORITY_CLASS) requires administrator
privileges. */
DWORD curr_prio = GetPriorityClass (proc);
if (curr_prio != prio)
{
debug_printf ("Failed to set priority 0x%x, revert from 0x%x to 0x%x",
prio, curr_prio, prev_prio);
SetPriorityClass (proc, prev_prio);
return false;
}
debug_printf ("Changed priority from 0x%x to 0x%x", prev_prio, curr_prio);
return true;
}
/* Minimal overlapped pipe I/O implementation for signal and commune stuff. */
BOOL

5
winsup/cygwin/release/3.6.0
View file

@ -43,3 +43,8 @@ What changed:
- Now using AVX/AVX2/AVX-512 instructions in signal handler does not
break their context.
- nice(2), setpriority(2) and sched_setparam(2) now fail with EACCES
or EPERM if Windows would silently set a lower priority
(HIGH_PRIORITY_CLASS instead of REALTIME_PRIORITY_CLASS) due to
missing administrator privileges.

2
winsup/cygwin/sched.cc
View file

@ -266,7 +266,7 @@ sched_setparam (pid_t pid, const struct sched_param *param)
set_errno (ESRCH);
return -1;
}
if (!SetPriorityClass (process, pclass))
if (!set_and_check_winprio (process, pclass))
{
CloseHandle (process);
set_errno (EPERM);

4
winsup/cygwin/syscalls.cc
View file

@ -3826,7 +3826,7 @@ setpriority (int which, id_t who, int value)
who = myself->pid;
if ((pid_t) who == myself->pid)
{
if (!SetPriorityClass (GetCurrentProcess (), prio))
if (!set_and_check_winprio (GetCurrentProcess (), prio))
{
set_errno (EACCES);
return -1;
@ -3875,7 +3875,7 @@ setpriority (int which, id_t who, int value)
error = EPERM;
else
{
if (!SetPriorityClass (proc_h, prio))
if (!set_and_check_winprio (proc_h, prio))
error = EACCES;
else
p->nice = value;