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"""
PIDs ops module
Provides PIDs related helper functions
"""
import common
import log
# list of valid PIDs' status, (R)unning, (S)leeping, (D)isk wait
PID_VALID_STATUS = set('RSD')
def get_pid_status(pid):
"""
Gets PID status valid/running/sleeping or not
Parameters:
pid: PID to be tested
Returns:
(bool) test result
"""
if pid != 0:
pid_str = pid
else:
pid_str = 'self'
try:
state, pid_name = _read_pid_state(pid_str)
return state, state in PID_VALID_STATUS, pid_name
except PermissionError as ex:
log.error("procfs file, {}".format(str(ex)))
except OSError as ex:
# handle silently, most likely PID has terminated
pass
return 'E', False, ''
def _read_pid_state(pid_str):
"""
Reads PID's /proc/PID/stat file for state and process name
Parameters:
pid_str: PID to be tested (number or 'self')
Returns:
state, pid_name
"""
# read procfs /proc/PID/stat file to get PID status
with open("/proc/{}/stat".format(pid_str), opener=common.check_link) as stat_file:
# split by '(' and ')' needed
# as processes/threads could have spaces in the name
line_split = stat_file.readline().strip().split(')')
pid_name = line_split[0].split('(')[1]
state = line_split[1].strip().split(' ')[0]
return state, pid_name
def is_pid_valid(pid):
"""
Check if PID is valid (get_pid_status wrapper)
Parameters:
pid: PID to be tested
Returns:
(bool) test result
"""
return get_pid_status(pid)[1]