added more code

CPE435/Lab4/Process_A.c

@@ -0,0 +1,73 @@
+/***********************************************************************************
+		Code  Inherited from Anon
+		Massively Modified by Prawar Poudel, 3 Feb 2020 (pp0030@uah.edu)
+		Modified by Noah Eid, 30 Jan 2021 (nae0005@uah.edu)
+************************************************************************************/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/ipc.h>
+#include <sys/shm.h>
+#include <unistd.h>
+
+#include "line.h"
+
+/*
+	Process A creates a shared memory segment
+	Process A attaches a pointer to the shared memory segment created
+	.. then it writes an integer value and a character value to it
+	Process A will then print that character every 4 seconds to terminal
+	.. a number of times
+
+	Process B will can also access the shared memory segment and change
+	.. the character being printed
+
+	After the printing operation is done, Process A will detach and delete the shared memory segment
+	
+*/
+main(void)
+{  
+    int  i, id  ;
+    struct info *ctrl;
+    
+	// create the shared memory segment 
+	// .. id is the file identifier of the shared memory segment 
+	// .. if the key is shared, any process can attach to this shared memory segment 
+	// .. 0666 is the file permission for the shared memory segment
+    if ( (id = shmget( key,MSIZ,IPC_CREAT | 0666) ) < 0 )
+    {
+	   //error…; 
+	   printf("error 1\n");
+	   exit(1) ; 
+    }
+
+	// attach a local pointer to the shared memory segment created
+	// .. exit if fails
+    if ( (ctrl = (struct info *) shmat( id, 0, 0)) <= (struct info *) (0) )
+	{
+		//error … ; 
+     	printf("error 2\n");
+		exit(1) ;  
+	}
+
+	// put some initial data in the shared memory so that we will just print the things before ProcessB is run
+	ctrl->c = 'a';
+	ctrl->length = 10;
+
+	// print line every 4 seconds
+	for (i = 0 ; i <ctrl->length ; i++ )
+	{
+		 putchar (ctrl->c);
+		 putchar ('\n');
+		 sleep(4);
+	}
+
+	//now detach the pointer from the shared memory
+	shmdt(ctrl);
+	//let us delete the shared memory
+	shmctl(id,IPC_RMID,NULL);
+	
+	//job done
+}
+

CPE435/Lab4/Process_B.c

@@ -0,0 +1,57 @@
+/***********************************************************************************
+		Code  Inherited from Anon
+		Massively Modified by Prawar Poudel, 3 Feb 2020 (pp0030@uah.edu)
+		Modified by Noah Eid, 30 Jan 2021 (nae0005@uah.edu)
+************************************************************************************/
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/ipc.h>
+#include <sys/shm.h>
+
+#include "line.h"
+
+
+/*
+	
+	Process B can change the contents of the shared memory that Process A is using
+	./ProcessB <char> <int>
+	
+*/
+
+main(int argc, char *argv[])
+{  
+    	int  id  ;
+    	struct info *ctrl;
+    
+	if (argc < 3) 
+	{
+		//error…;
+		exit(3);
+	}
+	// get the id of the already created shared memory segment
+	// .. function to create is same as getting id of the already created shared memory segment
+	if ( (id = shmget( key,MSIZ, 0 )) < 0 )
+    	{
+		//error … ; 
+		exit(1) ; 
+	}
+   
+  	// attach a local pointer to the shared memory
+  	 ctrl = (struct info *) shmat( id, 0, 0);
+	if ( ctrl <= (struct info *) (0) )
+    	{
+		//error … ; 
+		exit(1) ;  
+	}
+	
+	/* copy command line data to shared memory  */
+   	ctrl->c = argv[1][0] ;
+   	ctrl->length = atoi(argv[2]);
+
+   
+   	//detach the pointer from the shared memory 
+   	// .. we do not need to delete here, can be done in either of the process
+   	shmdt(ctrl);
+   	exit(0);
+ }

CPE435/Lab4/Process_C.c

@@ -0,0 +1,89 @@
+/***********************************************************************************
+		Code  Inherited from Anon
+		Massively Modified by Prawar Poudel, 3 Feb 2020 (pp0030@uah.edu)
+************************************************************************************/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/ipc.h>
+#include <sys/shm.h>
+
+#include "header.h"
+
+/*
+	Process C creates a shared memory segment
+	Process C attaches a pointer to the shared memory segment created
+	.. then it writes an integer value and a character value to it
+	.. it prints the character value for the integer number of times
+	.. then it waits on Process D to update the value of integer and the character
+	.. .. this will be indicated by the flag value being set to 1 by Process D 
+	.. after the same printing operation is done, Process C will detach and delete the shared memory segment
+	
+*/
+main(void)
+{  
+    int  i, id  ;
+    struct info *ctrl;
+    
+	// create the shared memory segment 
+	// .. id is the file identifier of the shared memory segment 
+	// .. if the key is shared, any process can attach to this shared memory segment 
+	// .. 0666 is the file permission for the shared memory segment
+    if ( (id = shmget( key,MSIZ,IPC_CREAT | 0666) ) < 0 )
+    {
+	   //error…; 
+	   printf("error 1\n");
+	   exit(1) ; 
+    }
+
+	// attach a local pointer to the shared memory segment created
+	// .. exit if fails
+    if ( (ctrl = (struct info *) shmat( id, 0, 0)) <= (struct info *) (0) ){
+    //error … ; 
+     	printf("error 2\n");
+	exit(1) ;  }
+
+	// put some initial data in the shared memory so that we will just print the things before Process D is run
+	ctrl->c = 'a';
+	ctrl->length = 10;
+	ctrl->flag = 0;
+
+	// print the character ctrl->c for ctrl->length times in a single line
+		for (i = 0 ; i <ctrl->length ; i++ )
+		{
+			 putchar (ctrl->c);
+			 putchar (' ');
+		}
+ putchar('\n');
+	
+	// flushing stdout just in case
+	fflush(stdout);
+	
+	// signal Process D that Process C is ready for next round, which will be printed below
+	ctrl->flag = 2;
+	
+	// wait for the flag to be set in processB to 1
+	// .. flag is 0 right now
+	// .. once processB starts to run, it will set the flag to 1
+	while(ctrl->flag!=1);
+	
+	
+	// print the character ctrl->c for ctrl->length times in a single line 
+		for (i = 0 ; i <ctrl->length ; i++ )
+		{
+			 putchar (ctrl->c);
+			 putchar (' ');
+		}
+	putchar ('\n');
+	// flushing stdout just in case
+	fflush(stdout);
+	
+	//now detach the pointer from the shared memory
+	shmdt(ctrl);
+	//let us delete the shared memory
+	shmctl(id,IPC_RMID,NULL);
+	
+	//job done
+}
+

CPE435/Lab4/Process_D.c

@@ -0,0 +1,51 @@
+/***********************************************************************************
+		Code  Inherited from Anon
+		Massively Modified by Prawar Poudel, 3 Feb 2020 (pp0030@uah.edu)
+************************************************************************************/
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/ipc.h>
+#include <sys/shm.h>
+
+#include "header.h"
+
+main(int argc, char *argv[])
+{  
+    int  id  ;
+    struct info *ctrl;
+    
+	if (argc < 3) 
+	{
+		//error…;
+		exit(3);
+	}
+	// get the id of the already created shared memory segment
+	// .. function to create is same as getting id of the already created shared memory segment
+	// .. notice the difference between the flags used in Process C and Process D
+	if ( (id = shmget( key,MSIZ, 0 )) < 0 )
+    {
+		//error … ; 
+		exit(1) ; 
+	}
+   
+   // attach a local pointer to the shared memory
+   ctrl = (struct info *) shmat( id, 0, 0);
+	if ( ctrl <= (struct info *) (0) )
+    {
+		//error … ; 
+		exit(1) ;  
+	}
+	// wait until Process C is ready to receive from process D
+	while(ctrl->flag==0);
+	
+	/* copy command line data to shared memory  */
+   ctrl->c = argv[1][0] ;
+   ctrl->length = atoi(argv[2]);
+   ctrl->flag = 1;
+   
+   //detach the pointer from the shared memory 
+   // .. we do not need to delete here, can be done in either of the process
+   shmdt(ctrl);
+   exit(0);
+ }

CPE435/Lab4/header.h

@@ -0,0 +1,7 @@
+struct info {
+             char c;
+             int length;
+			 char flag;
+};
+key_t  key = 1243 ;
+#define  MSIZ  sizeof(struct info)

CPE435/Lab4/info.h

@@ -0,0 +1,8 @@
+struct info
+{
+    float value1, value2;
+    float sum;
+    int flag;
+};
+#define KEY ((key_t)(1234))
+#define MSIZ sizeof(struct info)

CPE435/Lab4/line.h

@@ -0,0 +1,6 @@
+struct info {
+             char c;
+             int length;
+};
+#define  key ((key_t)(1243))
+#define  MSIZ  sizeof(struct info)

CPE435/Lab4/process1.c

@@ -0,0 +1,69 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/ipc.h>
+#include <sys/shm.h>
+
+#include "info.h"
+
+
+main(void)
+{  
+    int  i, id;
+    struct info *ctrl;
+    int v1, v2;
+	int choice;
+
+	// create the shared memory segment 
+	// .. id is the file identifier of the shared memory segment 
+	// .. if the key is shared, any process can attach to this shared memory segment 
+	// .. 0666 is the file permission for the shared memory segment
+    if ( (id = shmget( KEY,MSIZ,IPC_CREAT | 0666) ) < 0 )
+    {
+	   //error…; 
+	   printf("error 1\n");
+	   exit(1) ; 
+    }
+
+
+	// attach a local pointer to the shared memory segment created
+	// .. exit if fails
+    if ( (ctrl = (struct info *) shmat( id, 0, 0)) <= (struct info *) (0) )
+	{
+		//error … ; 
+     	printf("error 2\n");
+		exit(1) ;  
+	}
+	ctrl->flag=0;
+	ctrl->value1=0;
+	ctrl->value1=0;
+	ctrl->sum=0;
+    while(ctrl->flag!=-1)
+    {
+		//ctrl->flag=0;
+        // ask for numbers and set flag to 1
+        printf("Value 1: ");
+        scanf("%d",&v1);
+        printf("Value 2: ");
+        scanf("%d",&v2);
+        ctrl->value1 = v1;
+		ctrl->value2 = v2;
+		ctrl->flag = 1;
+		printf("Would you like to continue? Yes(1) or No(-1) : ");
+        scanf("%d",&choice);
+		if (choice == -1)
+		{
+			ctrl->flag = -1;
+		} else ctrl->flag=0;
+		
+    }
+
+
+	//now detach the pointer from the shared memory
+	shmdt(ctrl);
+	//let us delete the shared memory
+	shmctl(id,IPC_RMID,NULL);
+	
+	//job done
+}
+

CPE435/Lab4/process2.c

@@ -0,0 +1,46 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/ipc.h>
+#include <sys/shm.h>
+
+#include "info.h"
+
+int main()
+{
+    int  id;
+    struct info *ctrl;
+    
+	id = shmget( KEY,MSIZ, 0 );
+	// get the id of the already created shared memory segment
+	// .. function to create is same as getting id of the already created shared memory segment
+	if ( id < 0 )
+    	{
+		//error … ; 
+		exit(1) ; 
+	}
+   
+  	// attach a local pointer to the shared memory
+  	 ctrl = (struct info *) shmat( id, 0, 0);
+	if ( ctrl <= (struct info *) (0) )
+    	{
+		//error … ; 
+		exit(1) ;
+	}
+
+    while (ctrl->flag!=-1)
+    {
+    	// if flag is 1, add the numbers from shared memory, set flag to 0
+		if (ctrl->flag==1)
+		{
+			ctrl->sum = ctrl->value1+ctrl->value2;
+			printf("Sum: %f + %f = %f\n", ctrl->value1, ctrl->value2, ctrl->sum);
+			ctrl->flag = 0;
+		}
+    }
+   
+   	//detach the pointer from the shared memory 
+   	// .. we do not need to delete here, can be done in either of the process
+   	shmdt(ctrl);
+   	exit(0);
+}