사전 지식 ¶
root@zeropage:~# ps -efjc UID PID PPID PGID SID CLS PRI STIME TTY TIME CMD root 1 0 0 0 TS 23 Oct15 ? 00:00:00 init [2] root 2 1 0 0 TS 5 Oct15 ? 00:00:00 [ksoftirqd/0] root 3 1 0 0 TS 29 Oct15 ? 00:00:00 [events/0] root 4 1 0 0 TS 28 Oct15 ? 00:00:00 [khelper] root 5 1 0 0 TS 23 Oct15 ? 00:00:00 [kthread] root 7 5 0 0 TS 19 Oct15 ? 00:00:00 [kacpid] root 60 5 0 0 TS 29 Oct15 ? 00:00:00 [kblockd/0] root 86 5 0 0 TS 24 Oct15 ? 00:00:00 [pdflush] root 87 5 0 0 TS 24 Oct15 ? 00:00:00 [pdflush] root 89 5 0 0 TS 22 Oct15 ? 00:00:00 [aio/0] root 88 1 1 1 TS 24 Oct15 ? 00:00:01 [kswapd0] root 674 1 1 1 TS 22 Oct15 ? 00:00:00 [kseriod] root 943 1 1 1 TS 24 Oct15 ? 00:00:00 [kjournald] root 1095 1 1 1 TS 24 Oct15 ? 00:00:01 [kjournald] root 1096 1 1 1 TS 24 Oct15 ? 00:00:02 [kjournald] root 1097 1 1 1 TS 24 Oct15 ? 00:00:00 [kjournald] root 1098 1 1 1 TS 24 Oct15 ? 00:00:01 [kjournald] root 1099 1 1 1 TS 24 Oct15 ? 00:00:00 [kjournald] daemon 1191 1 1191 1191 TS 22 Oct15 ? 00:00:00 /sbin/portmap root 1314 1 1313 1313 TS 24 Oct15 ? 00:00:00 /usr/sbin/syslogd bind 1323 1 1323 1323 TS 21 Oct15 ? 00:00:00 /usr/sbin/named -u bind 105 1334 1 1334 1334 TS 21 Oct15 ? 00:00:00 /usr/bin/dbus-daemon-1 --system 104 1366 1 1366 1366 TS 23 Oct15 ? 00:00:00 /usr/sbin/exim4 -bd -q30m root 1372 1 1371 1371 TS 18 Oct15 ? 00:00:00 /usr/sbin/inetutils-inetd root 1387 1 1303 1303 TS 14 Oct15 ? 00:00:00 /bin/sh /usr/bin/mysqld_safe root 1417 1387 1303 1303 TS 14 Oct15 ? 00:00:00 /bin/sh /usr/bin/mysqld_safe mysql 1418 1417 1303 1303 TS 23 Oct15 ? 00:06:23 /usr/sbin/mysqld --basedir=/usr --datad root 1419 1417 1303 1303 TS 23 Oct15 ? 00:00:00 logger -p daemon.err -t mysqld_safe -i root 1461 1 1461 1461 TS 24 Oct15 ? 00:00:00 /usr/sbin/sshd root 1475 1 1303 1303 TS 14 Oct15 ? 00:03:00 /usr/local/jdk/jre/bin/java -Djava.util root 1481 1 1481 1481 TS 23 Oct15 ? 00:00:00 /usr/sbin/vsftpd root 1485 1 1485 1485 TS 21 Oct15 ? 00:00:00 /usr/sbin/famd -T 0 daemon 1497 1 1497 1497 TS 23 Oct15 ? 00:00:00 /usr/sbin/atd root 1500 1 1500 1500 TS 23 Oct15 ? 00:00:00 /usr/sbin/cron root 1538 1 1538 1538 TS 23 Oct15 tty1 00:00:00 /sbin/getty 38400 tty1 root 1540 1 1540 1540 TS 23 Oct15 tty2 00:00:00 /sbin/getty 38400 tty2 root 1541 1 1541 1541 TS 23 Oct15 tty3 00:00:00 /sbin/getty 38400 tty3 root 1542 1 1542 1542 TS 23 Oct15 tty4 00:00:00 /sbin/getty 38400 tty4 root 1543 1 1543 1543 TS 23 Oct15 tty5 00:00:00 /sbin/getty 38400 tty5 root 1544 1 1544 1544 TS 23 Oct15 tty6 00:00:00 /sbin/getty 38400 tty6 root 5722 1 5722 5722 TS 23 Oct16 ? 00:00:01 /usr/sbin/apache2 -k start -DSSL www-data 5724 5722 5722 5722 TS 23 Oct16 ? 00:00:00 /usr/sbin/fcgi-pm -k start -DSSL www-data 11061 5722 5722 5722 TS 24 22:30 ? 00:00:01 /usr/sbin/apache2 -k start -DSSL www-data 11123 5722 5722 5722 TS 22 22:54 ? 00:00:04 /usr/sbin/apache2 -k start -DSSL www-data 11184 5722 5722 5722 TS 23 23:05 ? 00:00:02 /usr/sbin/apache2 -k start -DSSL www-data 11360 5722 5722 5722 TS 23 23:30 ? 00:00:00 /usr/sbin/apache2 -k start -DSSL www-data 11392 5722 5722 5722 TS 20 23:32 ? 00:00:03 /usr/sbin/apache2 -k start -DSSL www-data 11393 5722 5722 5722 TS 23 23:32 ? 00:00:00 /usr/sbin/apache2 -k start -DSSL www-data 11394 5722 5722 5722 TS 23 23:32 ? 00:00:00 /usr/sbin/apache2 -k start -DSSL www-data 11395 5722 5722 5722 TS 24 23:32 ? 00:00:00 /usr/sbin/apache2 -k start -DSSL www-data 11396 5722 5722 5722 TS 23 23:32 ? 00:00:00 /usr/sbin/apache2 -k start -DSSL www-data 11397 5722 5722 5722 TS 23 23:32 ? 00:00:00 /usr/sbin/apache2 -k start -DSSL root 11434 1461 11434 11434 TS 24 23:41 ? 00:00:00 sshd: sapius@pts/0 root 11436 11434 11436 11436 TS 24 23:41 pts/0 00:00:00 -bash root 11453 11436 11453 11436 TS 22 23:41 pts/0 00:00:00 ps -efjc
사전지식 ¶
PPID 가 1인 프로세스를 작성하기 위해서 지켜야할 rule
자식의 프로세스가 종료되기 전에 부모 프로세스가 종료되면 자식의 PPID는 1번 PID로 설정된다.
2 부연설명
새로운 세션을 만든다. 일반적으로 tty 를 부여해야하지만, 부여하지 않을 경우 터미널이 없는 세션으로 생성된다.
3 부연설명
상대경로 지정으로 일어나는 프로그램내의 문제해결 (안해도 무관)
1. fork 호출하여 자식 프로세스 생성. 부모프로세스 종료 2. setsid 이용 새로운 세션 생성, 현재 프로세스의 PID가 세션 제어권을 가지도록 설정 3. chdir 프로세스가 루트에서 작업하도록 변경1 부연설명
자식의 프로세스가 종료되기 전에 부모 프로세스가 종료되면 자식의 PPID는 1번 PID로 설정된다.
2 부연설명
새로운 세션을 만든다. 일반적으로 tty 를 부여해야하지만, 부여하지 않을 경우 터미널이 없는 세션으로 생성된다.
3 부연설명
상대경로 지정으로 일어나는 프로그램내의 문제해결 (안해도 무관)
sample code ¶
~cpp
#include <sys/types.h>
#include <sys/stat.h>
#include <stdio.h>
#include <fcntl.h>
int main()
{
pid_t pid;
if (( pid = fork()) < 0)
exit(0);
// 부모프로세스를 종료한다.
else if(pid != 0)
exit(0);
//setsid();
chdir("/");
// 여기에 프로그램 본체를 넣는다.
setsid();
while(1)
{
sleep(1);
}
}
result ¶
root@zeropage:~# ps -ejfc UID PID PPID PGID SID CLS PRI STIME TTY TIME CMD root 1 0 0 0 TS 23 Oct15 ? 00:00:00 init [2] root 2 1 0 0 TS 5 Oct15 ? 00:00:00 [ksoftirqd/0] root 3 1 0 0 TS 29 Oct15 ? 00:00:00 [events/0] root 4 1 0 0 TS 28 Oct15 ? 00:00:00 [khelper] root 5 1 0 0 TS 23 Oct15 ? 00:00:00 [kthread] root 7 5 0 0 TS 19 Oct15 ? 00:00:00 [kacpid] root 60 5 0 0 TS 29 Oct15 ? 00:00:00 [kblockd/0] root 86 5 0 0 TS 24 Oct15 ? 00:00:00 [pdflush] root 87 5 0 0 TS 24 Oct15 ? 00:00:00 [pdflush] root 89 5 0 0 TS 22 Oct15 ? 00:00:00 [aio/0] root 88 1 1 1 TS 24 Oct15 ? 00:00:01 [kswapd0] root 674 1 1 1 TS 22 Oct15 ? 00:00:00 [kseriod] root 943 1 1 1 TS 24 Oct15 ? 00:00:00 [kjournald] root 1095 1 1 1 TS 24 Oct15 ? 00:00:01 [kjournald] root 1096 1 1 1 TS 23 Oct15 ? 00:00:02 [kjournald] root 1097 1 1 1 TS 24 Oct15 ? 00:00:00 [kjournald] root 1098 1 1 1 TS 24 Oct15 ? 00:00:01 [kjournald] root 1099 1 1 1 TS 24 Oct15 ? 00:00:00 [kjournald] daemon 1191 1 1191 1191 TS 22 Oct15 ? 00:00:00 /sbin/portmap root 1314 1 1313 1313 TS 23 Oct15 ? 00:00:00 /usr/sbin/syslogd bind 1323 1 1323 1323 TS 21 Oct15 ? 00:00:00 /usr/sbin/named -u bind 105 1334 1 1334 1334 TS 21 Oct15 ? 00:00:00 /usr/bin/dbus-daemon-1 --system 104 1366 1 1366 1366 TS 23 Oct15 ? 00:00:00 /usr/sbin/exim4 -bd -q30m root 1372 1 1371 1371 TS 18 Oct15 ? 00:00:00 /usr/sbin/inetutils-inetd root 1387 1 1303 1303 TS 14 Oct15 ? 00:00:00 /bin/sh /usr/bin/mysqld_safe root 1417 1387 1303 1303 TS 14 Oct15 ? 00:00:00 /bin/sh /usr/bin/mysqld_safe mysql 1418 1417 1303 1303 TS 24 Oct15 ? 00:06:23 /usr/sbin/mysqld --basedir=/usr --datad root 1419 1417 1303 1303 TS 23 Oct15 ? 00:00:00 logger -p daemon.err -t mysqld_safe -i root 1461 1 1461 1461 TS 24 Oct15 ? 00:00:00 /usr/sbin/sshd root 1475 1 1303 1303 TS 14 Oct15 ? 00:03:01 /usr/local/jdk/jre/bin/java -Djava.util root 1481 1 1481 1481 TS 23 Oct15 ? 00:00:00 /usr/sbin/vsftpd root 1485 1 1485 1485 TS 21 Oct15 ? 00:00:00 /usr/sbin/famd -T 0 daemon 1497 1 1497 1497 TS 23 Oct15 ? 00:00:00 /usr/sbin/atd root 1500 1 1500 1500 TS 23 Oct15 ? 00:00:00 /usr/sbin/cron root 1538 1 1538 1538 TS 23 Oct15 tty1 00:00:00 /sbin/getty 38400 tty1 root 1540 1 1540 1540 TS 23 Oct15 tty2 00:00:00 /sbin/getty 38400 tty2 root 1541 1 1541 1541 TS 23 Oct15 tty3 00:00:00 /sbin/getty 38400 tty3 root 1542 1 1542 1542 TS 23 Oct15 tty4 00:00:00 /sbin/getty 38400 tty4 root 1543 1 1543 1543 TS 23 Oct15 tty5 00:00:00 /sbin/getty 38400 tty5 root 1544 1 1544 1544 TS 23 Oct15 tty6 00:00:00 /sbin/getty 38400 tty6 root 5722 1 5722 5722 TS 23 Oct16 ? 00:00:01 /usr/sbin/apache2 -k start -DSSL www-data 5724 5722 5722 5722 TS 23 Oct16 ? 00:00:00 /usr/sbin/fcgi-pm -k start -DSSL www-data 11061 5722 5722 5722 TS 23 22:30 ? 00:00:01 /usr/sbin/apache2 -k start -DSSL www-data 11123 5722 5722 5722 TS 23 22:54 ? 00:00:05 /usr/sbin/apache2 -k start -DSSL www-data 11184 5722 5722 5722 TS 23 23:05 ? 00:00:02 /usr/sbin/apache2 -k start -DSSL www-data 11360 5722 5722 5722 TS 23 23:30 ? 00:00:00 /usr/sbin/apache2 -k start -DSSL www-data 11392 5722 5722 5722 TS 23 23:32 ? 00:00:04 /usr/sbin/apache2 -k start -DSSL www-data 11394 5722 5722 5722 TS 23 23:32 ? 00:00:00 /usr/sbin/apache2 -k start -DSSL www-data 11395 5722 5722 5722 TS 23 23:32 ? 00:00:01 /usr/sbin/apache2 -k start -DSSL www-data 11396 5722 5722 5722 TS 23 23:32 ? 00:00:00 /usr/sbin/apache2 -k start -DSSL www-data 11397 5722 5722 5722 TS 23 23:32 ? 00:00:00 /usr/sbin/apache2 -k start -DSSL root 11434 1461 11434 11434 TS 23 23:41 ? 00:00:00 sshd: sapius@pts/0 root 11436 11434 11436 11436 TS 24 23:41 pts/0 00:00:00 -bash '''root 11503 1 11503 11503 TS 23 23:49 ? 00:00:00 ./test''' www-data 11508 5722 5722 5722 TS 23 23:50 ? 00:00:00 /usr/sbin/apache2 -k start -DSSL www-data 11509 5722 5722 5722 TS 23 23:50 ? 00:00:00 /usr/sbin/apache2 -k start -DSSL www-data 11511 5722 5722 5722 TS 24 23:50 ? 00:00:00 /usr/sbin/apache2 -k start -DSSL root 11521 11436 11521 11436 TS 23 23:50 pts/0 00:00:00 ps -ejfc
