0
파이썬 데몬 프로세스가 있습니다. 이 데몬 프로세스는 명령이 호출 될 때마다 내 데몬에 대한 호출을 처리하도록 스레드를 생성합니다. 스레드 내에서 , 나는 몇 가지 명령을 실행하는 동안파이썬은 통신을하고 stdin이 기본 일 때 subprocess.popen을 읽지 않습니다. 없음
def __executeCommand(self, cmd):
try:
self.__assertEmptyCommand(cmd)
logger.debug('Executing command : '+str(cmd))
#kept for use after analysis
#cmd = cmd.split(' ')
#proc = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=False)
proc = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=True)
(output, error) = proc.communicate()
returnCode = proc.returncode
logger.debug('Command execution finished: Cmd:'+ str(cmd) + "\nReturn code:" \
+ str(returnCode) + "\nOutput:" + str(output) + "\nError:" + str(error))
if output is '':
output = []
returnOutput = output
if(output != [] and output[-1] == '\n'):
returnOutput = output[:-1]
return (returnCode, str(returnOutput), str(error))
처럼 같은 쉘 명령을 실행하기 위해 파이썬 하위 프로세스는 popen을 사용 proc.communicate()는 반환하지 않습니다. 내가 스레드가 다음 를 실행 된 아래의 부모 데몬의 strace를 체크 이는 popen에서 쉘을 실행 한 자식 PID의 strace를 보면서 strace를 출력
### Looking at strace for PID -> 14879 -> Main Daemon process ###
[[email protected] ~]# strace -p 14879
Process 14879 attached - interrupt to quit
select(0, NULL, NULL, NULL, {1, 122000}) = 0 (Timeout)
select(0, NULL, NULL, NULL, {2, 0}) = 0 (Timeout)
select(0, NULL, NULL, NULL, {2, 0}) = 0 (Timeout)
select(0, NULL, NULL, NULL, {2, 0}) = 0 (Timeout)
select(0, NULL, NULL, NULL, {2, 0}) = 0 (Timeout)
select(0, NULL, NULL, NULL, {2, 0}) = 0 (Timeout)
했다. 그래서 다시 추적이 생성
### Looking at strace for PID -> 24294 -> Child Process process ###
[[email protected] ~]# strace -p 24294
Process 24294 attached - interrupt to quit
restart_syscall(<... resuming interrupted call ...>) = 0
nanosleep({0, 2000001}, NULL) = 0
nanosleep({0, 2000001}, NULL) = 0
nanosleep({0, 2000001}, NULL) = 0
nanosleep({0, 2000001}, NULL) = 0
nanosleep({0, 2000001}, NULL) = 0
nanosleep({0, 2000001}, NULL) = 0
나는 데몬 프로세스를 실행에 GDB를 부착 I이었다 자식 프로세스에 GDB 부착는 popen 코드
### attaching GDB to main Daemon Process ###
[[email protected] ~]# gdb attach 14879
GNU gdb (GDB) Red Hat Enterprise Linux (7.0.1-42.el5.HYDRA)
Copyright (C) 2009 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type "show copying"
--snip--
(gdb) info thread
11 Thread 0x406c4940 (LWP 15072) 0x00000035ee00e291 in nanosleep() from /lib64/libpthread.so.0
10 Thread 0x410c5940 (LWP 15073) 0x00000035ee00b1c0 in [email protected]@GLIBC_2.3.2()
from /lib64/libpthread.so.0
9 Thread 0x41ac6940 (LWP 15075) 0x00000035ee00b1c0 in [email protected]@GLIBC_2.3.2()
from /lib64/libpthread.so.0
8 Thread 0x424c7940 (LWP 15078) 0x00000035ee00e291 in nanosleep() from /lib64/libpthread.so.0
7 Thread 0x42ec8940 (LWP 15081) 0x00000035ee00b1c0 in [email protected]@GLIBC_2.3.2()
from /lib64/libpthread.so.0
6 Thread 0x438c9940 (LWP 15084) 0x00000035ee00cd91 in sem_wait() from /lib64/libpthread.so.0
5 Thread 0x442ca940 (LWP 15085) 0x00000035ed4cc3f2 in select() from /lib64/libc.so.6
4 Thread 0x44ccb940 (LWP 15088) 0x00000035ee00dc0b in accept() from /lib64/libpthread.so.0
3 Thread 0x49cd3940 (LWP 24090) 0x00000035ee00cd91 in sem_wait() from /lib64/libpthread.so.0
2 Thread 0x47ed0940 (LWP 24281) 0x00000035ee00d9eb in read() from /lib64/libpthread.so.0 -----------------> Thread common for PID -> 24294
* 1 Thread 0x2b34ca2d7610 (LWP 14879) 0x00000035ed4cc3f2 in select() from /lib64/libc.so.6
(gdb) thread 2
[Switching to thread 2 (Thread 0x47ed0940 (LWP 24281))]#0 0x00000035ee00d9eb in read()
from /lib64/libpthread.so.0
(gdb) bt
#0 0x00000035ee00d9eb in read() from /lib64/libpthread.so.0
#1 0x00000035ee8bfc41 in read (self=<value optimized out>, args=<value optimized out>)
from /usr/lib64/libpython2.4.so.1.0
--snip--
#20 0x00000035ee895ad8 in call_function (f=0x2c00013339e0) at Python/ceval.c:3656
#21 PyEval_EvalFrame (f=0x2c00013339e0) at Python/ceval.c:2163
#22 0x00000035ee895c8b in call_function (f=0x2c0002bb9a20) at Python/ceval.c:3645
#23 PyEval_EvalFrame (f=0x2c0002bb9a20) at Python/ceval.c:2163
#24 0x00000035ee895c8b in call_function (f=0x2c0002136020) at Python/ceval.c:3645
---Type <return> to continue, or q <return> to quit---q
를 실행 한 스레드의 다음과 같은 스택 추적을 보았다
[[email protected] ~]# gdb attach 24294
GNU gdb (GDB) Red Hat Enterprise Linux (7.0.1-42.el5.HYDRA)
Copyright (C) 2009 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type "show copying"
--snip--
(gdb) bt
#0 0x00000035ee00e291 in nanosleep() from /lib64/libpthread.so.0
#1 0x00002b34ca068258 in SpinLock::SlowLock (this=0x2b34ca298440)
at src/allocator/base/spinlock.cc:104
#2 0x00002b34ca061526 in Lock (this=0x2b34ca298440, start=0x47ecd330, end=0x47ecd328,
N=<value optimized out>) at src/allocator/base/spinlock.h:90
#3 tcmalloc::CentralFreeList::RemoveRange (this=0x2b34ca298440, start=0x47ecd330, end=0x47ecd328,
N=<value optimized out>) at src/allocator/central_freelist.cc:219
#4 0x00002b34ca059ffe in tcmalloc::ThreadCache<false>::FetchFromCentralCache (
this=0x2c00000305c0, cl=<value optimized out>, byte_size=48)
at src/allocator/thread_cache.cc:159
#5 0x00002b34ca05e420 in Allocate (this=0x2c0000030580, size=<value optimized out>)
at src/allocator/thread_cache.h:331
#6 allocateWithSizeUpdate (this=0x2c0000030580, size=<value optimized out>)
at src/allocator/tcmalloc_heap.h:110
#7 allocate (this=0x2c0000030580, size=<value optimized out>) at src/allocator/stats_heap.h:77
#8 tcmalloc::Heapifier<tcmalloc::StatsHeap<false> >::allocate (this=0x2c0000030580,
size=<value optimized out>) at src/allocator/heap.h:107
#9 0x00002b34ca0794f2 in unlimited_cpp_alloc (old_ptr=0x0, new_size=<value optimized out>)
at src/allocator/tcmalloc.cc:850
--snip--
을 다음과 같이 나는 (일 왜 자식 프로세스는 또한 FD 공에 스핀 록 (표준 입력) 및 FD 0의 읽기() 응답을 기다리는 주요 데몬을 기다리고 있습니다 확실하지 않다 소음). 위의 내용은 항상 발생하지는 않지만 특정 순간과 다른 순간에 발생합니다.
감사합니다.