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Commit 9c17462

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1 parent e37e35b commit 9c17462

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17 files changed

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17 files changed

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‎기말고사/답안/10.c

Lines changed: 67 additions & 0 deletions
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1+
#include <stdio.h>
2+
#include <stdlib.h>
3+
#include <unistd.h>
4+
#include <errno.h>
5+
#include <fcntl.h>
6+
7+
#define NAMESIZE 50
8+
#define DUMMY 0
9+
10+
struct employe{
11+
char name[NAMESIZE];
12+
int salary;
13+
int pid;
14+
};
15+
16+
int main(int argc, char *argv[])
17+
{
18+
struct flock lock;
19+
struct employe record;
20+
int fd, flags, length, pid;
21+
22+
if (argc < 2) {
23+
fprintf(stderr, "Usage :%s file \n",argv[0]);
24+
exit(1);
25+
}
26+
27+
if((fd = open(argv[1], O_RDWR)) < 0) {
28+
fprintf(stderr, "Open eror :%s file \n",argv[1]);
29+
exit(1);
30+
}
31+
32+
if ((flags = fcntl(fd, F_GETFL, DUMMY)) == -1) {
33+
fprintf(stderr, "fcntl F_GETFL error\n");
34+
exit(1);
35+
}
36+
37+
flags |= O_APPEND;
38+
39+
if (fcntl(fd, F_SETFL, flags) == -1) {
40+
fprintf(stderr, "fcntl F_SETFL error\n");
41+
exit(1);
42+
}
43+
44+
pid = getpid();
45+
46+
while (1) {
47+
printf("Enter employee name : ");
48+
scanf("%s", record.name);
49+
50+
if(record.name[0] == '.')
51+
break;
52+
53+
printf("Enter employee salary : ");
54+
scanf("%d", &record.salary);
55+
record.pid = pid;
56+
length = sizeof(record);
57+
58+
if (write(fd, (char *)&record, length) != length) {
59+
fprintf(stderr, "record write error\n");
60+
exit(1);
61+
}
62+
}
63+
64+
close(fd);
65+
exit(0);
66+
}
67+

‎기말고사/답안/11.c

Lines changed: 61 additions & 0 deletions
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1+
#include <stdio.h>
2+
#include <stdlib.h>
3+
#include <unistd.h>
4+
#include <fcntl.h>
5+
6+
#define NAMESIZE 50
7+
8+
struct employee {
9+
char name[NAMESIZE];
10+
int salary;
11+
int pid;
12+
};
13+
14+
int main(int argc, char *argv[])
15+
{
16+
struct flock lock;
17+
struct employee record;
18+
int fd, recnum, pid;
19+
long position;
20+
21+
if ((fd = open(argv[1], O_RDWR)) == -1) {
22+
perror(argv[1]);
23+
exit(1);
24+
}
25+
26+
pid = getpid();
27+
while (1) {
28+
printf("\nEnter record number :");
29+
scanf("%d", &recnum);
30+
if (recnum < 0)
31+
break;
32+
position = recnum * sizeof(record);
33+
lock.l_type= F_WRLCK;
34+
lock.l_whence = 0;
35+
lock.l_start = position;
36+
lock.l_len = sizeof(record);
37+
if (fcntl(fd, F_SETLKW, &lock) == -1) {
38+
perror(argv[1]);
39+
exit(2);
40+
}
41+
lseek(fd, position, 0);
42+
if (read(fd, (char *)&record, sizeof(record)) == 0) {
43+
printf("record %d not found\n", recnum);
44+
lock.l_type = F_UNLCK;
45+
fcntl(fd, F_SETLK, &lock);
46+
continue;
47+
}
48+
49+
printf("Employee: %s, salary: %d\n", record.name, record.salary);
50+
record.pid = pid;
51+
printf("Enter new salaray: ");
52+
scanf("%d", &record.salary);
53+
lseek(fd, position, 0);
54+
write(fd, (char *)&record, sizeof(record));
55+
lock.l_type = F_UNLCK;
56+
fcntl(fd, F_SETLK, &lock);
57+
58+
}
59+
close(fd);
60+
exit(0);
61+
}

‎기말고사/답안/12.c

Lines changed: 62 additions & 0 deletions
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1+
#include <stdio.h>
2+
#include <string.h>
3+
#include <stdlib.h>
4+
#include <unistd.h>
5+
#include <fcntl.h>
6+
#include <sys/mman.h>
7+
#include <sys/stat.h>
8+
9+
#define FILE_MODE (S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH)
10+
11+
int main(int argc, char *argv[])
12+
{
13+
int fdin, fdout;
14+
void *src, *dst;
15+
struct stat statbuf;
16+
17+
if (argc != 3) {
18+
printf("usage : %s <fromfile> <tofile>\n", argv[0]);
19+
exit(1);
20+
}
21+
22+
if ((fdin = open(argv[1], O_RDONLY)) < 0) { /* fromfile 열기 */
23+
printf("can't open %s for reading\n", argv[1]);
24+
exit(1);
25+
}
26+
27+
if ((fdout = open(argv[2], O_RDWR | O_CREAT | O_TRUNC, FILE_MODE)) < 0) { /* tofile 열기 */
28+
printf("cannot creat %s for writing\n", argv[2]);
29+
exit(1);
30+
}
31+
32+
if (fstat(fdin, &statbuf) < 0) { /* 입력 파일의 크기 획득 */
33+
printf("fstat() error\n");
34+
exit(1);
35+
}
36+
37+
if (lseek(fdout, statbuf.st_size - 1, SEEK_SET) == -1) { /* 출력 파일의 크기 조정 */
38+
printf("lseek() error\n");
39+
exit(1);
40+
}
41+
42+
if (write(fdout, "", 1) != 1) { /* 쓰기 가능 여부 검사 */
43+
printf("write() error");
44+
exit(1);
45+
}
46+
47+
/* mmap: 메모리 맵 입출력, 특정 크기만큼의 메모리를 지정, 시작주소와 길이를 인자로 주며, 영역보호방식(PROT), 특성(FLAG)를 통해 메모리를 맵핑한다 */
48+
if ((src = mmap(0, statbuf.st_size, PROT_READ, MAP_SHARED, fdin, 0)) == MAP_FAILED) { /* ADDR, LENGTH, PROT, FLAG, FD, OFFSET */
49+
printf("mmap() error for input\n");
50+
exit(1);
51+
}
52+
53+
if ((dst = mmap(0, statbuf.st_size, PROT_READ | PROT_WRITE, MAP_SHARED, fdout, 0)) == MAP_FAILED) {
54+
printf("mmap() error for output\n");
55+
exit(1);
56+
}
57+
58+
memcpy(dst, src, statbuf.st_size); /* 파일 복사를 수행 */
59+
exit(0);
60+
}
61+
62+

‎기말고사/답안/13.c

Lines changed: 109 additions & 0 deletions
Original file line numberDiff line numberDiff line change
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1+
#include <stdio.h>
2+
#include <stdlib.h>
3+
#include <unistd.h>
4+
#include <pthread.h>
5+
6+
void *ssu_thread1(void *arg);
7+
void *ssu_thread2(void *arg);
8+
9+
pthread_mutex_t mutex1 = PTHREAD_MUTEX_INITIALIZER;
10+
pthread_mutex_t mutex2 = PTHREAD_MUTEX_INITIALIZER;
11+
pthread_cond_t cond1 = PTHREAD_COND_INITIALIZER;
12+
pthread_cond_t cond2 = PTHREAD_COND_INITIALIZER;
13+
14+
int count = 0;
15+
int input = 0;
16+
int t1 = 0, t2 = 0;
17+
18+
int main(void)
19+
{
20+
pthread_t tid1, tid2;
21+
int status;
22+
23+
if (pthread_create(&tid1, NULL, ssu_thread1, NULL) != 0) {
24+
fprintf(stderr, "pthread_create error\n");
25+
exit(1);
26+
}
27+
28+
if (pthread_create(&tid2, NULL, ssu_thread2, NULL) != 0) {
29+
fprintf(stderr, "pthread_create error\n");
30+
exit(1);
31+
}
32+
33+
while (1) {
34+
printf("2개 이상의 개수 입력: ");
35+
scanf("%d", &input);
36+
37+
if (input >= 2) {
38+
pthread_cond_signal(&cond1); // ssu_thread1을 깨움
39+
break;
40+
}
41+
}
42+
43+
pthread_join(tid1, (void*)status);
44+
pthread_join(tid2, (void*)status);
45+
46+
printf("complete\n");
47+
exit(0);
48+
}
49+
50+
void *ssu_thread1(void *arg) {
51+
while (1) {
52+
53+
pthread_mutex_lock(&mutex1); // 뮤텍스 락 설정
54+
55+
if (input < 2)
56+
pthread_cond_wait(&cond1, &mutex1); // 시그널 대기
57+
58+
if (input == count) {
59+
pthread_cond_signal(&cond2); // ssu_thread2에 시그널 전송
60+
break;
61+
}
62+
63+
if (count == 0) {
64+
t2++;
65+
count++;
66+
printf("Thread 1 : %d\n", t1);
67+
} else if (count % 2 == 0) {
68+
t1 += t2;
69+
count++;
70+
printf("Thread 1 : %d\n", t1);
71+
}
72+
73+
pthread_cond_signal(&cond2); // ssu_thread2에 시그널 전송
74+
pthread_cond_wait(&cond1, &mutex1); // 시그널 대기
75+
pthread_mutex_unlock(&mutex1); // 뮤텍스 락 해제
76+
}
77+
return NULL;
78+
}
79+
80+
void *ssu_thread2(void *arg) {
81+
while(1) {
82+
83+
pthread_mutex_lock(&mutex2); // 뮤텍스 락 설정
84+
85+
if (input < 2)
86+
pthread_cond_wait(&cond2, &mutex2); // 시그널 대기
87+
88+
if (input == count) {
89+
pthread_cond_signal(&cond1); // ssu_thread1에 시그널 전송
90+
break;
91+
}
92+
93+
if (count == 1) {
94+
count++;
95+
printf("Thread 2 : %d\n", t2);
96+
} else if (count % 2 == 1) {
97+
t2 += t1;
98+
count++;
99+
printf("Thread 2 : %d\n", t2);
100+
}
101+
102+
pthread_cond_signal(&cond1); // ssu_thread1에 시그널 전송
103+
pthread_cond_wait(&cond2, &mutex2); // 시그널 대기
104+
pthread_mutex_unlock(&mutex2); // 뮤텍스 락 해제
105+
}
106+
return NULL;
107+
}
108+
109+

‎기말고사/답안/16.c

Lines changed: 43 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,43 @@
1+
#include <stdio.h>
2+
#include <stdlib.h>
3+
#include <unistd.h>
4+
#include <signal.h>
5+
#include <time.h>
6+
7+
void ssu_signal_handler(int signo);
8+
9+
int main(void)
10+
{
11+
struct sigaction sig_act;
12+
sigset_t blk_set;
13+
pid_t pid;
14+
15+
sigfillset(&blk_set); // 모든 시그널을 블록 시그널 셋에 추가
16+
sigdelset(&blk_set, SIGCHLD); // SIGCHLD를 블록 시그널 셋에서 제외
17+
18+
sigemptyset(&sig_act.sa_mask); // 시그널 셋 초기화
19+
sig_act.sa_flags = 0; // 시그널 플래그 초기화
20+
sig_act.sa_handler = ssu_signal_handler; // 시그널 핸들러 등록
21+
sigaction(SIGCHLD, &sig_act, NULL); // SIGCHLD 시그널에 대한 액션 변경
22+
23+
printf("before fork\n");
24+
if ((pid = fork()) < 0) {
25+
fprintf(stderr, "fork error\n");
26+
exit(1);
27+
} else if (pid != 0) {
28+
printf("after fork in parent, suspend...\n");
29+
sigsuspend(&blk_set);
30+
printf("after suspend\n");
31+
} else {
32+
printf("after fork in child, sleep...\n");
33+
sleep(3);
34+
}
35+
36+
exit(0);
37+
}
38+
39+
void ssu_signal_handler(int signo)
40+
{
41+
printf("in ssu_signal_handler() function\n");
42+
}
43+

‎기말고사/답안/17.c

Lines changed: 40 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,40 @@
1+
#include <stdio.h>
2+
#include <stdlib.h>
3+
#include <unistd.h>
4+
#include <pthread.h>
5+
6+
void *ssu_thread1(void *arg);
7+
void *ssu_thread2(void *arg);
8+
9+
pthread_t glo_tid;
10+
11+
int main(void)
12+
{
13+
pthread_t loc_tid[2];
14+
int i;
15+
16+
// 스레드 생성
17+
pthread_create(&loc_tid[0], NULL, ssu_thread1, NULL);
18+
pthread_create(&loc_tid[1], NULL, ssu_thread2, NULL);
19+
20+
sleep(5);
21+
22+
for (i = 0; i < 2; i++)
23+
if (loc_tid[i] == glo_tid)
24+
printf("second thread assigns it's tid to global tid\n");
25+
26+
exit(0);
27+
}
28+
29+
void *ssu_thread1(void *arg)
30+
{
31+
printf("in ssu_thread1\n");
32+
return NULL;
33+
}
34+
35+
void *ssu_thread2(void *arg)
36+
{
37+
printf("in ssu_thread2\n");
38+
glo_tid = pthread_self();
39+
return NULL;
40+
}

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