UIT CE LAB HDH Lab3

TRNG I HC CNG NGH THNG TIN

KHOA K THUT MY TNH

TI LIU:

HNG DN THC HNH

H IU HNH

Nhm bin son:

- ThS. Phan nh Duy

- ThS. Phm Vn Phc

- ThS. Nguyn Vit Quc

- KS. Nguyn Hu Nhn

- KS. L Vn La

- KS. Trn Vn Quang

Thng 3 nm 2015

NI DUNG CC BI THC HNH

Phn 1: Lp trnh trn Linux

Bi 1: Hng dn ci t Ubuntu v cc lnh c bn ca shell

Bi 2: C bn lp trnh shell

Phn 2: Thc hnh h iu hnh

Bi 3: Qun l tin trnh

Bi 4: nh thi CPU

Bi 5: ng b ha tin trnh, tiu trnh

Bi 6: Qun l b nh

Phn 3: Bi tp ln

CC PHN MM THIT B S DNG TRONG MN THC HNH

- Phn mm VMware

- H iu hnh Ubuntu

Chng 1. Qun l tin trnh, tiu trnh

Sinh vin s thc hnh cc thao tc lin quan ti tin trnh trong h iu

hnh. Mc ch ca bi thc hnh ny l gii thiu v tin trnh, tiu trnh

trong h iu hnh linux. Cui cng sinh vin s p dng lp trnh a tiu

trnh (multithreading) nhm gim thi gian thc thi hin song song. Bi

thc hnh bao gm cc phn chnh:

Tm hiu v tin trnh, tiu trnh.

1.1 Tin trnh trong linux

Mt tin trnh, trong linux c gi l task, l mt thc th ca mt

chng trnh ang chy trong linux. Chng hn nu 10 ngi trn mt

server cng s dng mt chng trnh, nh emacs (trnh son tho), th ta

c 10 tin trnh emacs cng chy trn server , mc d chng u xut

pht t mt chng trnh.

Trong linux, ta c th dng lnh ps e hin th cc tt c cc tin

trnh ang chy trong h thng, hnh minh ha

Hnh 1. Tin trnh trong linux

Trong , PID l s id ca tin trnh, TTY cho bit tin trnh thuc vo

terminal no v CMD l tn ca chng trnh ang c chy.

ID ca tin trnh (PID) l duy nht cho mt tin trnh trong h thng.

H iu hnh s dng bin counter 32-bit t ID cho tin trnh. Mt khi

tin trnh c khi to, bin counter s c tang ln v gi tr ca n tr

thnh PID ca tin trnh va c khi to .

hin th nhiu thng tin cc tin trnh gn lin vi mt terminal ta g

lnh ps -l.

Hnh 2. Hin th thng tin tin trnh gn lin vi terminal hin ti

Ct S l mt trong cc ct quan trng nht, n cho bit trng thi ca

tin trnh. Cc tin trnh c th thuc vo cc trng thi nh bng sau

Code Name

D

R

S

T

Z

Uninteruptible sleep

Runnable (on run queue)

Sleeping

Traced hoc Stopped

Defunct (zombie)

Nu ta s dng lnh ps el, ta nhn thy rng hu ht cc tin trnh u

ang trong trng thi ng (sleeping S). Bi v, tt c ang i input x

l. Trong Hnh 2, ta c th thy PPID ca ps chnh l PID ca bash, do ps

c kch hot t bash, khi bash c gi l tin trnh cha ca tin trnh

ps. Nh vy sau khi khi to tin trnh ps xong, bash chuyn sang trng

thi ng.

Bi v c mi quan h cha-con gia cc tin trnh, nn linux h tr lnh

hin th mi quan h ny di dng cy thng qua lnh pstree. Ta c th

nhn ra rng cy quan h ny bt ngun t init, sau n cc tin trnh

cha (PPID) v cc daemon (cc tin trnh chy ngm khng tng tc trc

tip vi ngi dng).

1.2 Signals

Trong linux, cc tn hiu c xem nh mt knh giao tip bt ng b vi

mt tin trnh. Mt signal ngt mt tin trnh ang chy bnh thng

chuyn h thng sang phc v s kin khc. C rt nhiu loi signal trong

linux, sinh vin c th tham kho trong ti liu nh km. T terminal, ta c

th dng kill gi signal ti mt tin trnh. V d:

Hnh 3. Hy tin trnh bng lnh trong terminal

V d trn dng lnh KILL gi tn hiu SIGKILL ti tin trnh ng

300 giy. Ta c th dng lnh ny ny loi b cc tin trnh khng mong

mun vi cc la chn SIGKILL hoc SIGTERM. i vi SIGKILL tin

trnh s b hy ngay lp tc, trong khi SIGTERM th tin trnh c thi gian

x l cc thao tc.

C 3 cch bt mt tn hiu trong lp trnh. N c th b t chi

(khng phi tt c tn hiu u b t chi), n c th c gi ti mt

handler mc nh hoc gi ti mt handler nh trc. c th bt tn

hiu nh trc, ta c th dng hm signal (trong th vin signal.h) ly

s hiu v a ch ca mt hm bt tn hiu. V d di y bt s kin

CTRL-C (SIGINT signal interrupt).

Hnh 4. Bt tn hiu SIGINT

1.3 To tin trnh

To tin trnh t tin trnh cha 1.3.1

Trong linux, tin trnh c to ra bng cch nhn i mt tin trnh

bn mt li gi h thng fork. Trong C, ta c th thc hin bng lnh

fork():

#include

#include

pid_t fork(void);

Sau khi to tin trnh con t tin trnh cha, cc tin trnh s dng chung

code nhng s dng stack v heap ring. Hm fork tr v gi tr l PID, ta

c th s dng gi tr ny phn bit cc process. i vi tin trnh con,

hm fork tr v gi tr 0, nhng trong hm fork cha s tr v PID ca hm

mi to (nu gi tr tr v m l li). Sinh vin chy v d sau:

#include /* Symbolic Constants */

#include /* Primitive System Data Types */

#include /* Input/Output */

#include /* General Utilities */

int main(){

pid_t pid;

pid=fork();

if(pid==0)

printf("Child process, gia tri pid=%d\n",pid);

else

printf("Parent Proces, gia tri pid=%d\n",pid);

exit(0);

}

Hm wait c th c s dng hm cha i cho n khi hm con kt

thc. V d sau y khin tin trnh cha phi i tin trnh con hon thnh

trc.

#include /* Symbolic Constants */

#include /* Primitive System Data Types */

#include /* Input/Output */

#include /* General Utilities */

int main(){

pid_t pid;

pid=fork();

if(pid==0)

printf("Child process, gia tri pid=%d\n",pid);

else {

wait(NULL);

printf("Parent Proces, gia tri pid=%d\n",pid);

}

exit(0);

}

Khi to tin trnh t chng trnh c sn 1.3.2

Hm fork gip to mt tin trnh mi t tin trnh hin ti, tuy nhin,

nu chng ta mun chy mt chng trnh c sn th chng ta cn thc

hin mt li gi h thng. Hm execl s thay th tin trnh hin ti bi tin

trnh mi c gi t mt chng trnh. V d:

#include

#include

int main(){

execl("/usr/bin/gedit", "gedit", "foo.c, NULL);

exit(1);

}

Nu chng ta mun m to mt file vi tn l foo.c, ng ngha vi

vic ta g lnh gedit foo.c trong terminal, ta c th truyn cc tham s cho

hm execl nh execl("/usr/bin/gedit", "gedit", "foo.c, NULL);

Trong lp trnh ta c th kt hp lnh fork v lnh execl tin trnh

va tip tc chy v va to thm tin trnh mi t vic m thm chng

trnh khc. u tin, ta dng lnh fork to mt tin trnh con mi. Sau

, trong tin trnh con ta dng hm execl khi to tin trnh mi.

1.4 Tiu trnh

phn ny, sinh vin s lm quen vi cc thao tc c bn ca tiu trnh.

Tiu trnh trong linux c s dng thng qua gi th vin chun pthreads.

Chng ta cn thm c -pthread khi bin dch chng trnh c th bin

dch chng trnh c s dng tiu trnh. V d, nu ta mun bin dch file

c tn l threadprog.c ta s dng lnh nh sau:

$gcc pthread o threadprog threadprog.c

Ngoi ra, khi lp trnh chng ta cn khai bo th vin pthreads vo

bng cch thm pthread.h vo header.

Khi to tiu trnh 1.4.1

Mt tiu trnh c to ra bng cch gi hm pthread_create. Hm

pthread_create c nh ngha y nh sau:

int pthread_create(pthread_t *thread, const pthread_attr_t *attr, void

*(*start_routine)(void *), void *arg);

Pthread_create tr v mt s integer, nu tiu trnh to thnh cng s

tr v 0, ngc li l s khc 0.

i s u tin tr ti mt kiu cu trc c tn pthread_t. Cu trc

ny gi cc thng tin hu ch v mt tiu trnh (thread). V th, mi

khi to mi mt tiu trnh, ta cn cp pht b nh lu tr thng

tin ny.

i s th hai l mt con tr ti cu trc pthread_attr_t. Cu trc

ny cha cc thuc tnh ca tiu trnh nh s lng b nh cn cp

pht cho stack ca tiu trnh. Mc nh b nh cn thit l 512K.

Nu s lng tiu trnh qu nhiu c th gy ra trn b nh. V th

ta c th cp pht b nh cho stack nh hn.

#define SMALL_STACK 131072 //128K for stack

pthread_attr_t thread_attr;

pthread_attr_init(&thread_attr);

pthread_attr_setstacksize(&thread_attr, SMALL_STACK);

Lu , ta c th s dng li cu trc thuc tnh ny cho cc tiu

trnh khc nhau.

i s th 3 l con tr hm ch ti hm m tiu trnh s thc thi.

i s cui cng l i s c truyn cho hm s thc thi c

khai bo i s th 3.

V d v tiu trnh 1.4.2

Di y l mt v d v s dng pthread_create. Cc dng lnh di s

to mt tiu trnh thc thi hm fn

#include

#include

#include

#define SMALL_STACK 131072 //128K for stack

pthread_attr_t thread_attr;

void* fn(void* arg);

int main(int argc, char** argv)

{

pthread_attr_init(&thread_attr);

pthread_attr_setstacksize(&thread_attr, SMALL_STACK);

pthread_t th;

pthread_create(&th, &thread_attr, fn, (void*)14);

void* val;

thread_join(th, &val);

return 0;

}

void* fn(void* arg){

printf("arg = 0x%x\n", (int)arg);

return NULL;

}

Hm pthread_join lm cho hm main i cho n khi tiu trnh kt

thc.

1.5 Tng kt

Bi thc hnh ny hng dn sinh vin tm hiu v tin trnh trong

linux. Qua , gip sinh vin nm c cch thc c bn trong lp trnh

nh khi to tin trnh, tiu trnh, bt s kin trong lp trnh,...

1.6 Bi tp

1. V cy mi quan h ca danh sch cc tin trnh trong hnh bn di.

Ti mi nhnh, ghi ch tn v PID ca tin trnh (nh rng init lun

lun c PID l 1)

2. Sinh vin vit mt chng trnh c cha cc handler ca cc s kin

SIGHUP, SIGTERM, SIGINT. i vi mi handler in ra dng ch

cho bit chng trnh bt c tn hiu thnh cng.

Hng dn: sau khi vit xong chng trnh c tn ex-signals

Chy lnh ./ex-signals

Sau thc hin gi signal ti tin trnh ang chy. VD:

kill -SIGHUP pid

3. Cho chng trnh sau:

#include

#include

#include

#include

int main(){

pid_t pid;

int num_coconuts = 17;

pid = fork();

if(pid == 0) {

num_coconuts = 42;

exit(0);

} else {

wait(NULL); /*wait until the child terminates */ }

}

printf("I see %d coconuts!\n", num_coconuts);

exit(0);

}

Chng trnh s in g ra mn hnh? Gii thch ti sao.

4. Vit chng trnh lm cc cng vic sau theo th t:

a. In ra dng ch Thuc hanh he dieu hanh

b. M chng trnh gedit

c. i ngi dng nhn CTRL-C tt.

d. Khi ngi dng nhn CTRL-C, in dng ch Ban da nhan

CTRL-C.

5. Sinh vin b hm pthread_join trong v d mc 1.4.2. Sau bin

dch v chy li chng trnh. Chng trnh c in ra mn hnh ging

vi trc khng? Gii thch ti sao.

6. Sinh vin tm hiu thm v pthread_create nhm bit cch truyn

nhiu i s cho hm thc thi ca tiu trnh. Hy hin thc chng

trnh truyn MSSV v H Tn ca mnh cho tiu trnh v in ra mn

hnh.

PH LC

Chng 1. Qun l tin trnh, tiu trnh ...................................... 3

1.1 Tin trnh trong linux .......................................................... 3

1.2 Signals ................................................................................. 5

1.3 To tin trnh ....................................................................... 6

To tin trnh t tin trnh cha ................................... 6 1.3.1

Khi to tin trnh t chng trnh c sn ................ 8 1.3.2

1.4 Tiu trnh ............................................................................. 8

Khi to tiu trnh ...................................................... 9 1.4.1

V d v tiu trnh .................................................... 10 1.4.2

1.5 Tng kt ............................................................................. 10

1.6 Bi tp 10

TI LIU THAM KHO

1. http://www.ucs.cam.ac.uk/docs/course-notes/unix-

courses/Building/files/signals.pdf

2. http://manpages.ubuntu.com/manpages/lucid/man2/fork.2.html

3. http://manpages.ubuntu.com/manpages/saucy/man3/pthread_create.3

.html

4. http://manpages.ubuntu.com/manpages/saucy/man3/pthread_join.3.h

tml

UIT CE LAB HDH Lab3

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