Adding implementations for shared memory server client, zombie proccesses, and more

Author: kyriakos-2004

apocalypse.c

@@ -0,0 +1,16 @@
+#include<stdio.h>
+#include<unistd.h>
+ 
+int 
+main()
+{
+    int flag = 0;
+
+    while (fork() > 0)
+    {
+        flag++;
+        printf("%d\n", flag);
+    }
+
+    return 0;
+}

orphan.c

@@ -0,0 +1,14 @@
+#include <unistd.h>
+  
+int 
+main()
+{     
+    pid_t pid = fork();
+    
+    if (pid == 0)
+    {
+        sleep(30);
+    }
+  
+    return 0;
+}

portscanner.py

@@ -0,0 +1,15 @@
+import socket
+
+target = str(input("Enter ip of target to scan available ports, empty for localhost: "))
+
+for port in range(1,65535):
+        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        socket.setdefaulttimeout(0.1)
+        
+        if not target:
+            target = "127.0.0.1"
+
+        result = s.connect_ex((target,port))
+        if result == 0:
+            print("Port " + str(port) + " is open") 
+        s.close()

shared_memory/shm_reader.c

@@ -0,0 +1,66 @@
+#include<errno.h>
+#include<stdio.h>
+#include<stdlib.h>
+#include<string.h>
+#include<sys/ipc.h>
+#include<sys/shm.h>
+#include<sys/types.h>
+#include<unistd.h>
+
+#define BUF_SIZE 1024
+#define SHM_KEY 0x568547
+
+struct shmsegment 
+{
+   int cnt;
+   int opercompleted;
+   char buffer[BUF_SIZE];
+};
+
+int 
+main(int argc, char *argv[]) 
+{
+   int shmid;
+   struct shmsegment *shmp;
+   
+   shmid = shmget(SHM_KEY, sizeof(struct shmsegment), 0644 | IPC_CREAT);
+   if (shmid == -1) 
+   {
+      perror("Error getting the shared memory segment");
+      return 1;
+   }
+   
+   // Attach to shared memory segment to get a pointer to it
+   shmp = shmat(shmid, NULL, 0);
+   if (shmp == (void *) -1) 
+   {
+      perror("Error attaching to shared memory");
+      return 1;
+   }
+   
+   // Transfer data from shared memory segment to standard output
+   while (shmp->opercompleted != 1) 
+   {
+      printf("Memory segment contains : \n\"%s\"\n", shmp->buffer);
+      if (shmp->cnt == -1) 
+	  {
+         perror("Error reading shared memory segment");
+         return 1;
+      }
+	  
+      printf("RP: Read %d bytes from shared memory\n", shmp->cnt);
+      sleep(3);
+   }
+   
+   printf("Reading process has been completed\n");
+   printf("Detaching from shared memory\n");
+   
+   if (shmdt(shmp) == -1) 
+   {
+      perror("Unable to detach from shared memory");
+      return 1;
+   }
+   
+   printf("Reading process has been completed\n");
+   return 0;
+}

shared_memory/shm_writer.c

@@ -0,0 +1,106 @@
+#include<errno.h>
+#include<stdlib.h>
+#include<stdio.h>
+#include<string.h>
+#include<unistd.h>
+#include<sys/ipc.h>
+#include<sys/shm.h>
+#include<sys/types.h>
+
+#define BUF_SIZE 1024
+#define SHM_KEY 0x568547
+
+struct shmsegment 
+{
+   int cnt;
+   int opercompleted;
+   char buffer[BUF_SIZE];
+};
+
+int fill_buffer(char * buffptr, int size);
+
+int 
+main(int argc, char *argv[]) 
+{
+   int shmid, times;
+   int availspace;
+   struct shmsegment *shmp;
+   char *buffptr;
+   
+   shmid = shmget(SHM_KEY, sizeof(struct shmsegment), 0644 | IPC_CREAT);
+   if (shmid == -1) 
+   {
+      perror("Error creating shared memory");
+      return 1;
+   }
+   
+   // Attach to shared memory segment to get a pointer to it
+   shmp = shmat(shmid, NULL, 0);
+   if (shmp == (void *) -1) 
+   {
+      perror("Error attaching to shared memory");
+      return 1;
+   }
+   
+   // Transfer data from buffer to shared memory
+   buffptr = shmp->buffer;
+   availspace = BUF_SIZE;
+   
+   for (times = 0; times < 5; times++) 
+   {
+      shmp->cnt = fill_buffer(buffptr, availspace);
+      shmp->opercompleted = 0;
+      
+	  printf("WP: Wrote %d bytes in shared memory\n", shmp->cnt);
+      buffptr = shmp->buffer;
+      availspace = BUF_SIZE;
+      
+	  sleep(3);
+   }
+   
+   printf("WP: Wrote %d times\n", times);
+   shmp->opercompleted = 1;
+
+   if (shmdt(shmp) == -1) 
+   {
+      perror("Unable to detach from shared memory");
+      return 1;
+   }
+
+   if (shmctl(shmid, IPC_RMID, 0) == -1) 
+   {
+      perror("Unable to perform shared memory control operations");
+      return 1;
+   }
+   
+   printf("Writting process has been completed\n");
+   return 0;
+}
+
+int 
+fill_buffer(char* buffptr, int size) 
+{
+   static char c = 'K';
+   int fillcount;
+   
+   memset(buffptr, c, size - 1);
+   buffptr[size-1] = '\0';
+
+   if (c > 122)
+   {
+	c = 65;
+   }
+   
+   if ( (c >= 65) && (c <= 122) ) 
+   {
+      	if ( (c >= 91) && (c <= 96) ) 
+	{
+        	c = 65;
+      	}
+   }
+   
+   fillcount = strlen(buffptr);
+   c++;
+   
+   return fillcount;
+}

variadic_template.cpp

@@ -0,0 +1,25 @@
+#include <iostream>
+
+void 
+print()
+{
+    std::cout << "I am called last and i am empty.\n";
+}
+ 
+template <typename T, typename... Types>
+void 
+print(T arg1, Types... arg2)
+{
+    std::cout << arg1 << std::endl;
+ 
+    print(arg2...);
+}
+ 
+int main()
+{
+    print(1, 5020345, 0.5772156649,
+          "I will print any and all arguments",
+          "The defrosting has begun\n");
+ 
+    return 0;
+}

zombie.c

@@ -0,0 +1,19 @@
+#include <stdlib.h>
+#include <unistd.h>
+
+int 
+main()
+{
+    pid_t child_pid = fork();
+  
+    if (child_pid > 0)
+    {
+        sleep(50);
+    }
+    else
+    {	    
+        exit(0);
+    }
+
+    return 0;
+}