Concept explainers
Explanation of Solution
Implementation of a concurrent prethreaded version of the TINY web server:
Modified code for “sbuf.h” file:
The modified code for “sbuf.h” from section 12.5.4 in book is given below:
#ifndef SBUF_HEADER
#define SBUF_HEADER
#include "csapp.h"
typedef struct
{
int *buf; /* Buffer array */
int n; /* Maximum number of slots */
int front; /* buf[(front+1)%n] is first item */
int rear; /* buf[rear%n] is last item */
sem_t mutex; /* Protects accesses to buf */
sem_t slots; /* Counts available slots */
sem_t items; /* Counts available items */
} sbuf_t;
//Function declaration
void sbuf_init(sbuf_t *sp, int n);
void sbuf_deinit(sbuf_t *sp);
void sbuf_insert(sbuf_t *sp, int item);
int sbuf_remove(sbuf_t *sp);
//Function declaration for sbuf_empty
int sbuf_empty(sbuf_t *sp);
//Function declaration for sbuf_full
int sbuf_full(sbuf_t *sp);
#endif
Modified code for “sbuf.c” file:
The modified code for “sbuf.c” from section 12.5.4 in book is given below:
#include "csapp.h"
#include "sbuf.h"
/* Create an empty, bounded, shared FIFO buffer with n slots */
void sbuf_init(sbuf_t *sp, int n)
{
sp->buf = Calloc(n, sizeof(int));
sp->n = n; /* Buffer holds max of n items */
sp->front = sp->rear = 0; /* Empty buffer if front == rear */
Sem_init(&sp->mutex, 0, 1); /* Binary semaphore for locking */
Sem_init(&sp->slots, 0, n); /* Initially, buf has n empty slots */
Sem_init(&sp->items, 0, 0); /* Initially, buf has zero data items */
}
/* Clean up buffer sp */
void sbuf_deinit(sbuf_t *sp)
{
Free(sp->buf);
}
/* Insert item onto the rear of shared buffer sp */
void sbuf_insert(sbuf_t *sp, int item)
{
P(&sp->slots); /* Wait for available slot */
P(&sp->mutex); /* Lock the buffer */
sp->buf[(++sp->rear)%(sp->n)] = item; /* Insert the item */
V(&sp->mutex); /* Unlock the buffer */
V(&sp->items); /* Announce available item */
}
/* Remove and return the first item from buffer sp */
int sbuf_remove(sbuf_t *sp)
{
int item;
P(&sp->items); /* Wait for available item */
P(&sp->mutex); /* Lock the buffer */
item = sp->buf[(++sp->front)%(sp->n)]; /* Remove the item */
V(&sp->mutex); /* Unlock the buffer */
V(&sp->slots); /* Announce available slot */
return item;
}
//Function definition for empty buffer
int sbuf_empty(sbuf_t *sp)
{
//Declare variable
int ne;
//For lock the buffer
P(&sp->mutex);
ne = sp->front == sp->rear;
//For lock the buffer
V(&sp->mutex);
return ne;
}
//Function definition for full buffer
int sbuf_full(sbuf_t *sp)
{
//Declare variable
int fn;
//For lock the buffer
P(&sp->mutex);
fn = (sp->rear - sp->front) == sp->n;
//For lock the buffer
V(&sp->mutex);
return fn;
}
For code “tiny.c” and “tiny.h”:
Same code as section 11.6 in book.
sample.html:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>Home</title>
</head>
<body>
Tiny server Example
</body>
</html>
main.c:
#include <stdio.h>
#include "csapp.h"
#include "tiny.h"
#include "sbuf...
Want to see the full answer?
Check out a sample textbook solution
Chapter 12 Solutions
COMPUTER SYSTEMS&MOD MSGT/ET SA AC PKG
- Q1: I want his face in the shape of a balloon calculator Gray contains the addition of variables and a second box that shows the result and show it to be the solution of all mathematical equations in the language Python : 1- a a U ah ² (121 ²) + 20 (12132) = 10³² 12μ 12μ Where P P(x, y) is the oil film pressure. 2 ax 2- 3μU (L² P = C²R 4 ε sin (1+ε cos 0)³ 3arrow_forwardUse the created table as in Question 1, solve the problems as mentioned below. You will have to import the respective CSV files of the above created tables as without them, it is impossible to solve the questions below. If you are not able to upload the files successfully, do not leave the query questions. Just write the query to the best of your knowledge. Do not copy. To be graded for the screenshot answer, you must upload the CSV properly and paste the resulting screenshot of the queries as asked. Look at the sum of profits for each Product Sub-Category. Which sub-category is $31,069 below the average profit across all categories? Write the Query in box below. [4 Marks] Paste the screenshot of a portion of the answer below. [1 Marks Write a query to find the contribution of total Sales by the 'Home Office' Customer Segment in the year 2012? For example, if in 2012, the total sum of sales across all Customer segments is 100 and 'Home Office' contributes 30 to the sum of sales. Then…arrow_forwardDatabasearrow_forward
- Can you help me with this problemarrow_forwardGiven the following addresses, which two addresses conflict in the cache: The numb of locations in the cache is 2048, the cahche is indexed by address bits 15 to 5 and the tag bits are from 31 to 16. (a) 0x0000 0100 (b) 0x0000 1400 (c) 0x0010 0100 (d) 0x0100 0140arrow_forward5. RetailItem ClassWrite a class named RetailItem that holds data about an item in a retail store. The class should store the following data in attributes: item description, units in inventory, and price. Once you have written the class, write a program that creates three RetailItem objects and stores the following data in them: Description Units in Inventory PriceItem #1 Jacket 12 59.95Item #2 Designer Jeans 40 34.95Item #3 Shirt 20 24.95arrow_forward
- Write a class named Patient that has attributes for the following data: First name, middle name, and last name Address, city, state, and ZIP code Phone number Name and phone number of emergency contact The Patient class’s _ _init_ _ method should accept an argument for each attribute. The Patient class should also have accessor and mutator methods for each attribute. Next, write a class named Procedure that represents a medical procedure that has been performed on a patient. The Procedure class should have attributes for the following data: Name of the procedure Date of the procedure Name of the practitioner who performed the procedure Charges for the procedure The Procedure class’s _ _init_ _ method should accept an argument for each attribute. The Procedure class should also have accessor and mutator methods for each attribute. Next, write a program that creates an instance of the Patient class, initialized with sample data. Then, create three instances of the Procedure class,…arrow_forward1 Vo V₁ V3 V₂ V₂ 2arrow_forwardI want a full report on Sperani security according to Project Mingment.arrow_forward
- Given a 8-bit addressable (256) locations in memory and 32 locations in cache, 3 bits are in the cache Tag. What is the cache location for memory address of 0x0100 0100? Provide the answer in decimal form.arrow_forwardQ2: Solve the equation using the simplex method Max. Z 13x1 +11x2 Subject to constraints 4x1 +5x21500 5x1 +3x21575 x1 +2x2 <420 x1, x2≥0arrow_forwardBasically, you must build a desktop/android application that utilizes cryptographic techniques/protocols to secure communication (or data at rest). Try to achieve confidentiality, integrity, availability, authentication, non-repudiation (preferably all of them, otherwise few of them based on the requirement).You must demonstrate the use of these cryptographic techniques by showing some outputs/visualization results or captured traffic such as through Wireshark.1. Secure Chat ApplicationDescription: Build an encrypted chat application for desktop or Android that ensures confidentiality, integrity, authentication, and non-repudiation.Features:-- End-to-end encryption using AES-256 or Signal Protocol.--Digital signatures for non-repudiation.--Message integrity verification using HMAC.Secure login using two-factor authentication (2FA).--Server-side availability mechanisms (e.g., load balancing, backup storage). Technologies: Python (PyQt + PyCryptodome), Java (Android), Firebase for…arrow_forward
Computer Networking: A Top-Down Approach (7th Edi...Computer EngineeringISBN:9780133594140Author:James Kurose, Keith RossPublisher:PEARSON
Computer Organization and Design MIPS Edition, Fi...Computer EngineeringISBN:9780124077263Author:David A. Patterson, John L. HennessyPublisher:Elsevier Science
Network+ Guide to Networks (MindTap Course List)Computer EngineeringISBN:9781337569330Author:Jill West, Tamara Dean, Jean AndrewsPublisher:Cengage Learning
Concepts of Database ManagementComputer EngineeringISBN:9781337093422Author:Joy L. Starks, Philip J. Pratt, Mary Z. LastPublisher:Cengage Learning
Prelude to ProgrammingComputer EngineeringISBN:9780133750423Author:VENIT, StewartPublisher:Pearson Education
Sc Business Data Communications and Networking, T...Computer EngineeringISBN:9781119368830Author:FITZGERALDPublisher:WILEY