init commit

3sem/kr/001.c

@@ -0,0 +1,54 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <wait.h>
+#include <sys/ipc.h>
+#include <sys/sem.h>
+#include <sys/shm.h>
+#include <sys/file.h>
+
+int main(int argc, char** argv){
+
+    int id_of_shm = shmget(argv[1], sizeof(double) * 2, IPC_CREAT | 0666);
+    float* start_of_shm = shmat(id_of_shm, NULL, 0);
+
+    int sem_id = semget(IPC_PRIVATE, 1, IPC_CREAT | 0666);
+    semctl(sem_id, 0, SETVAL, 1);
+
+    struct sembuf p = {0, -1, 0}, v = {0,1,0};
+    
+
+    for(int i = 2; i < argc; i++){
+        pid_t pid = fork();
+        
+        if (pid == 0) {
+            FILE* in_file = fopen(argv[i], "r");
+            float sum = 0, n = 0;
+            float buf;
+            while(fscanf(in_file, "%f", &buf) != EOF){
+                sum += buf;
+                n++;
+            }
+
+            semop(sem_id, &p, 1);
+            start_of_shm[1] += sum;
+            start_of_shm[0] += n;
+            semop(sem_id, &v, 1);
+
+            fclose(in_file);
+            
+            return 0;
+        }
+
+    }
+
+    
+    while (wait(NULL) != -1 ){
+    }
+    printf("%f\n", start_of_shm[1] / start_of_shm[0]);
+    
+    semctl(sem_id, 0, IPC_RMID);
+    shmctl(id_of_shm, IPC_RMID, NULL);
+    
+
+    return 0;
+}

3sem/kr/002.c

@@ -0,0 +1,41 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <signal.h>
+#include <fcntl.h>
+
+volatile int counter = 0;
+volatile int signals = 0;
+
+int fd2;
+
+void handler(int sig) {
+    ++signals;
+    if (signals < 3) {
+        printf("%d\n", counter / 2);
+    } else {
+        lseek(fd2, 0, SEEK_SET);
+        char buf;
+        while (read(fd2, &buf, 1) > 0) {
+            write(1, &buf, 1);
+        }
+        exit(0);
+    }
+
+}
+
+int main(int argc, char** argv) {
+    signal(SIGINT, handler);
+
+    int fd1 = open(argv[1], O_RDONLY, 0666);
+    fd2 = open(argv[2], O_CREAT | O_WRONLY);
+
+    char buf;
+    while (read(fd1, &buf, 1) > 0) {
+        if (counter % 2 == 0) {
+            write(fd2, &buf, 1);
+        }
+        ++counter;
+    }
+
+    return 0;
+}

3sem/kr/01.c

@@ -0,0 +1,39 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/wait.h>
+#include <string.h>
+
+int
+main(int argc, char **argv)
+{
+    int fd[2];
+    pipe(fd);
+
+    if (!fork()) {
+        close(fd[1]);
+        dup2(fd[0], 0);
+        execlp("wc", "wc", NULL);
+        _exit(1);
+    }
+
+    close(fd[0]);
+    int file = open(argv[1], O_RDONLY);
+
+    char test = argv[2][0];
+    char buf[8];
+    while (read(file, buf, 8) == 8) {
+        if (buf[0] != test) {
+            continue;
+        }
+        printf("%s\n", buf);
+
+        write(fd[1], buf, 8);
+    }
+    close(fd[1]);
+
+    while (wait(NULL) != -1)
+        ;
+
+    return 0;
+}

3sem/kr/02.c

@@ -0,0 +1,34 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/wait.h>
+#include <string.h>
+
+int
+main(int argc, char **argv)
+{
+    int file = open(argv[1], O_RDONLY);
+    int file_out = open("tmp", O_WRONLY | O_CREAT | O_TRUNC, 0666);
+
+    dup2(file, 0);
+    dup2(file_out, 1);
+
+    char buf[101];
+    while (fgets(buf, 100, stdin) != NULL) {
+        for (int i = 0; i < strlen(buf); i++) {
+            if (!strncmp(buf + i, "begin", 5)) {
+                printf("{");
+                i += 4;
+            } else if (!strncmp(buf + i, "end", 3)) {
+                printf("}");
+                i += 2;
+            } else {
+                printf("%c", buf[i]);
+            }
+        }
+    }
+
+    rename("tmp", argv[1]);
+
+    return 0;
+}

3sem/kr/03.c

@@ -0,0 +1,33 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/wait.h>
+#include <string.h>
+
+int
+main(int argc, char **argv)
+{
+    int mas[5] = {0, 0, 0, 0, 0};
+
+    int num = 5, tmp;
+
+    while (scanf("%d", &tmp) == 1) {
+        for (int i = 0; i < 4; i++) {
+            mas[i] = mas[i + 1];
+        }
+        mas[4] = tmp;
+        num--;
+    }
+
+    // if (num < 0) {
+    //     num = 0;
+    // }
+    num = num < 0 ? 0 : num;
+
+    for (int i = num; i < 5; i++) {
+        printf("%d ", mas[i]);
+    }
+    printf("\n");
+
+    return 0;
+}

3sem/kr/signal.c

@@ -0,0 +1,13 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/wait.h>
+#include <string.h>
+#include <signal.h>
+
+int
+main(int argc, char **argv)
+{
+
+    return 0;
+}