feat: update structure

cs2106/labs/lab2/part2/file.txt

@@ -0,0 +1,2 @@
+This is a text file.
+CS2106 Introduction to Operating Systems is a cool module!

cs2106/labs/lab2/part2/lab2p2a.c

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+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/wait.h>
+
+int slow(char *name, int time, int n) {
+    for(int i=n; i<=n+4; i++) {
+        printf("%s: i = %d\n", name, i);
+        sleep(time);
+    }
+}
+
+sdf
+asdf
+as
+dfas
+f
+
+int main() {
+    int id;
+
+    if((id = fork()) != 0) {
+        int stat;
+        int my_id = getpid();
+        int parent_id = getppid();
+        printf("\nI am the parent.\n");
+        printf("My ID is %d\n", my_id);
+        printf("My parent's ID is %d\n", parent_id);
+        printf("My child's ID is %d\n\n", id);
+        slow("Parent", 1, 5);
+        printf("\nWaiting for child to exit.\n");
+        wait(&stat);
+        printf("CHILD HAS EXITED WITH STATUS %d\n", WEXITSTATUS(stat));
+    }
+    else 
+    {
+        id = getpid();
+        int parent_id = getppid();
+        printf("\nI am the child.\n");
+        printf("My ID is %d\n", id);
+        printf("My parent's ID is %d\n\n", parent_id);
+        slow("Child", 2, 10);
+        exit(25);
+    }
+}
+
+

cs2106/labs/lab2/part2/lab2p2b.c

@@ -0,0 +1,17 @@
+#include <stdio.h>
+
+int main(int ac, char **av, char **vp) {
+    printf("ac = %d\n", ac);
+    printf("Arguments:\n");
+
+    int i;
+
+    for(i=0; i<ac; i++)
+        printf("Arg %d is %s\n", i, av[i]);
+
+    i=0;
+    while(vp[i] != NULL) {
+        printf("Env %d is %s\n", i, vp[i]);
+        i++;
+    }
+}

cs2106/labs/lab2/part2/lab2p2c.c

@@ -0,0 +1,12 @@
+#include <unistd.h>
+#include <stdio.h>
+#include <sys/wait.h>
+
+int main() {
+    if(fork() ==  0) {
+        execlp("cat", "cat", "file.txt", NULL);
+    }
+    else
+        wait(NULL);
+}
+

cs2106/labs/lab2/part2/lab2p2d.c

@@ -0,0 +1,24 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <sys/wait.h>
+
+int main() {
+    int fp_in = open("./file.txt", O_RDONLY);
+    int fp_out = open("./talk.out", O_CREAT | O_WRONLY);
+
+    if(fork() == 0) {
+        dup2(fp_in, STDIN_FILENO);
+        dup2(fp_out, STDOUT_FILENO);
+        execlp("./talk", "talk", (char *) 0);
+        close(fp_in);
+        close(fp_out);
+    }
+    else
+        wait(NULL);
+
+}
+
+
+

cs2106/labs/lab2/part2/lab2p2e.c

@@ -0,0 +1,34 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <string.h>
+#include <sys/wait.h>
+
+int main() {
+    int p[2];
+    char str[] = "Hello this is the parent.";
+
+    // This creates a pipe. p[0] is the reading end,
+    // p[1] is the writing end.
+
+    if(pipe(p) < 0) 
+        perror("lab2p2e: ");
+
+    // We will send a message from father to child
+    if(fork() != 0) {
+        close(p[0]); // The the end we are not using.
+        write(p[1], str, strlen(str));
+        close(p[1]);
+        wait(NULL);
+    }
+    else
+    {
+        char buffer[128];
+
+        close(p[1]); // Close the writing end
+        read(p[0], buffer, 127);
+        printf("Child got the message \"%s\"\n", buffer);
+        close(p[0]);
+    }
+}
+

cs2106/labs/lab2/part2/lab2p2f.c

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+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <sys/wait.h>
+#include <fcntl.h>
+
+int main() {
+
+    printf("Be patient, the program will take around 7 seconds to run.\n");
+    printf("At the end you can do \"cat results.out\" to see the result.\n");
+
+    //
+    // Add code here to pipe from ./slow 5 to ./talk and redirect
+    // output of ./talk to results.out
+    // I.e. your program should do the equivalent of ./slow 5 | talk > results.out
+    // WITHOUT using | and > from the shell.
+    //
+
+}
+

cs2106/labs/lab2/part2/slow.c

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+#include <stdio.h>
+
+// For the sleep functiopn
+#include <unistd.h>
+
+// For the atoi function that converts
+// strings to integers
+#include <stdlib.h>
+
+int main(int ac, char **av) {
+    if(ac != 2) {
+        printf("\nCounts from specified integer n to n + 5\n");
+        printf("Usage: %s <integer>\n\n", av[0]);
+        exit(-1);
+    }
+
+    int n = atoi(av[1]);
+    int i;
+    for(i=n; i<=n+5; i++) {
+        printf("%d\n", i);
+        sleep(1);
+    }
+
+    printf("\nFinal value of i is %d\n\n", i);
+
+    exit(i);
+}
+
+

cs2106/labs/lab2/part2/talk.c

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+#include <stdio.h>
+
+#define BUF_SIZE    128
+
+int main() {
+    char input[128];
+    char *ret;
+    while(!feof(stdin)) {
+        ret = fgets(input, BUF_SIZE - 1, stdin);
+        if(ret != NULL)
+            printf("This is what I read: %s\n", input);
+    }
+}