self-defense with SIGSTOP

nohang

@@ -4,7 +4,7 @@ import os
 from time import sleep, time
 from operator import itemgetter
 from sys import stdout
-from signal import SIGKILL, SIGTERM
+from signal import SIGKILL, SIGTERM, SIGSTOP, SIGCONT
 
 start_time = time()
 
@@ -40,11 +40,106 @@ HR = '~' * 79
 print_total_stat = True
 
 
+stop_cont = False
+print_states_debug = False
+
+
+
 ##########################################################################
 
 # define functions
 
 
+
+
+
+def pid_to_state(pid):
+    return rline1('/proc/' + pid + '/stat').rpartition(')')[2][1]
+
+def stop():
+    print()
+    print('Stop running processes...')
+    t1 = time()
+    t2 = time()
+    stopped_list = []
+    for pid in os.listdir('/proc')[::-1]:
+        # only directories whose names consist only of numbers, except /proc/1/
+        if pid[0].isdecimal() is False or pid is '1' or pid == self_pid:
+            continue
+        try:
+            # print(pid)
+            if pid_to_state(pid) == 'R':
+                uid_r = pid_to_uid(pid)
+                oom_score_r = int(
+                    rline1('/proc/' + pid + '/oom_score')
+                    )
+                if uid_r != '0' and oom_score_r > 10:
+                    stopped_list.append(pid)
+                    print('Send SIGSTOP to {}, {}, {}...'.format(
+                        pid, pid_to_name(pid), pid_to_cmdline(pid)[:40]))
+                    os.kill(int(pid), SIGSTOP)
+                    t2 = time()
+        except FileNotFoundError:
+            continue
+        except ProcessLookupError:
+            continue
+    print('Stop time:', t2 - t1)
+    return stopped_list
+
+def cont(stopped_list):
+    print()
+    #print('Continue stopped processes...')
+    t1 = time()
+    if len(stopped_list) > 0:
+        for pid in stopped_list:
+            #print('Send SIGCONT to', [pid], pid_to_name(pid))
+            try:
+                os.kill(int(pid), SIGCONT)
+            except FileNotFoundError:
+                continue
+            except ProcessLookupError:
+                continue
+    t2 = time()
+    #print('All cont time: ', t2 - t1)
+
+def print_states():
+    if print_states_debug:
+        print()
+        t1 = time()
+        print('non-S states:')
+        for pid in os.listdir('/proc'):
+            # only directories whose names consist only of numbers, except /proc/1/
+            if pid[0].isdecimal() is False or pid is '1' or pid == self_pid:
+                continue
+            try:
+                s = pid_to_state(pid)
+                if s == 'S':
+                    continue
+                else:
+                    print('State: {}, [{}], {}, {}...'.format(
+                        s, pid, pid_to_name(pid), pid_to_cmdline(pid)[:40]))
+            except FileNotFoundError:
+                continue
+            except ProcessLookupError:
+                continue
+        t2 = time()
+        print('print state time:', t2 - t1)
+        print()
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
 def update_stat_dict_and_print(key):
 
     if key not in stat_dict:
@@ -488,6 +583,13 @@ def find_victim_and_send_signal(signal):
     Find victim with highest badness and send SIGTERM/SIGKILL
     """
 
+
+    if stop_cont:
+        print_states()
+        stopped_list = stop()
+
+
+
     pid, victim_badness = fattest()
     name = pid_to_name(pid)
 
@@ -695,12 +797,21 @@ def find_victim_and_send_signal(signal):
 
             try:
 
+
+
+
                 m = check_mem_and_swap()
                 ma = round(int(m[0]) / 1024.0)
                 sf = round(int(m[2]) / 1024.0)
                 print('\nMemory status before sending a signal:\nMemA'
                       'v: {} MiB, SwFree: {} MiB'.format(ma, sf))
 
+
+
+                if stop_cont:
+                    os.kill(int(pid), SIGCONT)
+
+
                 os.kill(int(pid), signal)
                 response_time = time() - time0
                 send_result = '\033[32mOK\033[0m; response time: {} ms'.format(
@@ -749,6 +860,16 @@ def find_victim_and_send_signal(signal):
         key = 'victim badness < min_badness'
         update_stat_dict_and_print(key)
 
+
+
+    if stop_cont:
+        print_states()
+        cont(stopped_list)
+        print_states()
+
+
+
+
     sleep_after_send_signal(signal)