LINUX进程和线程的基础与管理

.vi? WebApachehttpdApachehttpd.;LinuxLinux(Process Idenity NumberPID)(Parent Process ID,PPID)PIDPPIDPID(Child Process)1initinitinitinitinitps-afID1Linuxpstreepstree.LinuxLinuxI386PCB(Process Control Block)PCB.LinuxSWAP(zombie)exit.LinuxforkLinux? forkfork:#include#includepid_t fork();Linuxfork()/WebWebWebfork()systemstring(sh)stringshstringPATH(waitpid()-1.shellsystemexecexitsleepwaitpoppensystemhttpd.1.Linux(PID);(1)dfdfps -xdfdfpsfindps auxfind(2)shell2.Ctrl+CkillCPU;killLinux.LinuxinitinitLinuxID1,Linuxinitinit/etc/inittabInittabRHEL 4inittab:#inittab#author#Default runlevel.the runlevels used by rhs are:#0 - halt (do not set initdefault to this)#1 - single user mode#2 - multiuser,without nfs (the same as 3, if you do not haver networking)#3 - full multiuser mode#4 - unused#5 - X11#6 - reboot (do not set initdefault to this)#/5,id:5:initdefault:/etc/rc.d/rc.sysinit#system initialization.si:sysinit:/etc/rc.d/rc.sysinit10:0:wait:/etc/rc.d/rc 011:1:wait:/etc/rc.d/rc 112:2:wait:/etc/rc.d/rc 213:3:wait:/etc/rc.d/rc 314:4:wait:/etc/rc.d/rc 4/55/etc/rc.d/rcinit15:5:wait:/etc/rc.d/rc 516:6:wait:/etc/rc.d/rc 6/ctrl-alt-delete#trap ctrl-alt-deleteca:ctrlaltdel:/sbin/shutdown -t3 -r now#.#/2345ttyX/sbin/mingettyttyXmingetty#run gettys in standard runlevels1:2345:respawn:/sbin/mingetty tty12:2345:respawn:/sbin/mingetty tty23:2345:respawn:/sbin/mingetty tty34:2345:respawn:/sbin/mingetty tty45:2345:respawn:/sbin/mingetty tty56:2345:respawn:/sbin/mingetty tty6/5xdmxdmx:5:respawn:/etc/x11/prefdm -nodaemon#run xdm in runleverl 5Inittabid:runlevels:action:procees1.id122.runlevels1234535Linux7012(NFS)34563.actioninitinitrespawn4processprocesswait4processonce4processboot4processbootwait4processoffondemandondemand4processinitdefaultprocesssysinitbootbootwait4processpowerwait4processpowerfailnow4processctrlaltdelctrl+alt+del cessProcessinit/etc/rc.d/rcXXrcX/etc/rc.d/rc.X/etc/rc.d:#ls –l /etc/rc.d/total 112drwxr-xr-x 2 root root 4096 3/15 14:44 init.d-rxwr-xr-x 1 root root 2352 2004-3-17 rcdrwxr-xr-x 2 root root 4096 3/15 14:44 rc0.ddrwxr-xr-x 2 root root 4096 3/15 14:44 rc1.ddrwxr-xr-x 2 root root 4096 3/15 14:44 rc2.ddrwxr-xr-x 2 root root 4096 3/15 14:44 rc3.ddrwxr-xr-x 2 root root 4096 3/15 14:44 rc4.ddrwxr-xr-x 2 root root 4096 3/15 14:44 rc5.ddrwxr-xr-x 2 root root 4096 3/15 14:44 rc6.d-rxwr-xr-x 1 root root 2200 2004-3-17 rc.local-rxwr-xr-x 1 root root 2352 2004-3-17 rc.sysinit/etc/rc.d/rc5.d:#ls –l /etc/rc.d/rc5.dSKSKchkconfigshellinit/etc/inittabkill-SIGHUP 1init q.Linux1.Linux(thread)()CPUPOSIXPthreadLinux(LWP)/LWPCPUPthread2.Pthread(1)I/OI/O(2)(3)PthreadLinux3.Linux19991Linux 2.2fork2.2.x(thread)LinuxPthreadLinuxforkLinux 2.24096/Linux20011Lin