Assignment 5 Part 1 Submission

server/Makefile

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+# MUKESH JHA
+
+CC=$(CROSS_COMPILE)gcc
+CFLAGS=-Werror -Wall -g
+SOURCES=aesdsocket.c
+TARGET=aesdsocket
+OBJS=aesdsocket.o
+INCLUDE_DIR="." ## todo: ideally, it should be in the include folder 
+
+
+ ## a. Is compiled by the “all” and “default” target of a Makefile in the “server” directory and supports cross compilation, placing the executable file in the “server” directory and named aesdsocket.
+all: $(TARGET)
+
+default: $(TARGET)
+
+$(TARGET): $(OBJS)
+	$(CC) $(CFLAGS) -I$(INCLUDE_DIR) -o $(TARGET) $(OBJS) 
+
+clean:
+	rm -f $(OBJS) $(TARGET)
+
+#aesdsocket: aesdsocket.c aesdsocket.h aesdsocket.o
+#	$(CC) $(CFLAGS) -I$(INCLUDE_DIR) -o aesdsocket aesdsocket.o
+#	mv aesdsocket /usr/local/bin/aesdsocket  ## move the executable to /usr/bin/ location so that it can be exectued by deamon ## Permission issue

server/aesdsocket.c

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+#include "aesdsocket.h"
+
+// signal handler function declearation 
+void signal_handler(int);
+
+// global variables 
+int client_fd;
+int server_fd;
+int received_data_file_fd; 
+
+// main function 
+int main(int argc, char* argv[])
+{
+
+  // registr for signal
+  signal(SIGTERM, signal_handler);
+  signal(SIGINT, signal_handler);
+
+  // initialize required variables for the program
+  int bind_return=NO_ERROR;
+  int listen_return=NO_ERROR;
+  int optval=1;
+  struct addrinfo *servinfo=NULL;
+  //struct addrinfo *iterator=NULL;
+  struct addrinfo hints;
+
+  // initialize the hints 
+  memset(&hints, 0, sizeof (hints));
+  hints.ai_family = AF_UNSPEC;     
+  hints.ai_socktype = SOCK_STREAM; 
+  hints.ai_flags = AI_PASSIVE;     
+
+  //struct sockaddr_storage client_addr;
+  struct sockaddr_in client_addr;
+  socklen_t addr_size;
+  char client_ip_address[INET6_ADDRSTRLEN];
+  memset(client_ip_address, 0, sizeof (client_ip_address));
+  int number_of_bytes_sent = 0;
+  int number_of_bytes_read = 0;
+  char read_buffer[RECEIVE_PACKET_SIZE];
+
+ // getaddrinfo 
+  if(0 != getaddrinfo(NULL, PORT, &hints, &servinfo)) 
+  {
+      printf("Error in function getaddrinfo\n");
+      syslog(LOG_DEBUG, "Error in function getaddrinfo\n");
+      return ERROR;
+  }
+  else
+  {
+  	  syslog(LOG_DEBUG, "success in function getaddrinfo\n");
+      printf("success in function getaddrinfo\n");
+  }
+
+  //b. Opens a stream socket bound to port 9000, failing and returning -1 if any of the socket connection steps fail.
+  // socket 
+  server_fd = socket(servinfo->ai_family, servinfo->ai_socktype, servinfo->ai_protocol);
+  if(ERROR == server_fd)
+  { 
+      syslog(LOG_PERROR, "Error in function socket\n");
+      printf("Error in function socket\n");
+      return ERROR;
+  }
+  else
+  {
+      syslog(LOG_DEBUG, "success in function socket\n");
+      printf("success in function socket\n");
+   }
+
+  if (ERROR == setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR, &optval, sizeof(optval))) 
+  {
+      syslog(LOG_PERROR, "error in function setsockopt\n");
+      printf("error in function setsockopt\n");
+      return ERROR;
+  }
+  else
+  {
+      syslog(LOG_DEBUG, "succss in function setsockopt\n");
+      printf("succss in function setsockopt\n");
+   } 
+
+  bind_return = bind(server_fd, servinfo->ai_addr, servinfo->ai_addrlen);
+  if(ERROR == bind_return)
+  { 
+      syslog(LOG_PERROR, "error in function bind\n");
+      printf("error in function bind\n");
+      close(server_fd);
+      return ERROR;
+  }
+  else
+  {
+      syslog(LOG_DEBUG, "success in function bind\n");
+      printf("success in function bind\n");
+  } 
+
+  // free the memory 
+  freeaddrinfo(servinfo);
+
+  // c. Listens for and accepts a connection 
+  // listen to the address  
+  listen_return = listen(server_fd, LISTEN_BACKLOG);
+  if(ERROR == listen_return)
+  {  
+      syslog(LOG_PERROR, "error in function listen\n");
+      printf("error in function listen\n");
+      return ERROR;
+  }
+
+
+  // 5. Modify your program to support a -d argument which runs the aesdsocket application as a daemon. 
+  // When in daemon mode the program should fork after ensuring it can bind to port 9000.
+  if( (2 == argc) && (0 == strcmp(argv[1], "-d")) )
+  {
+  	syslog(LOG_DEBUG, "Starting the application aesdsocket as a daemon\n");
+    printf("Starting the application aesdsocket as a daemon\n");
+
+    daemon(0, 0);
+  }
+
+  // h. Restarts accepting connections from new clients forever in a loop until SIGINT or SIGTERM is received
+  printf("Entering While (true)\n");
+  while(true)
+  {  
+    addr_size = sizeof(client_addr);
+	// c. Listens for and accepts a connection  
+    client_fd = accept(server_fd, (struct sockaddr *)&client_addr, &addr_size);
+
+    // error in client request acceptance
+    if(ERROR==client_fd)
+    {
+        syslog(LOG_PERROR, "error in function accept\n");
+        printf("error in function aceept\n");
+        return ERROR;
+    }
+    else
+    {
+        syslog(LOG_DEBUG, "success in function accept\n");
+        printf("success in function accept\n");
+    } 
+
+    // d. Logs message to the syslog “Accepted connection from xxx” where XXXX is the IP address of the connected client. 
+    inet_ntop(AF_INET, &(client_addr.sin_addr), client_ip_address, sizeof (client_ip_address));
+    syslog(LOG_DEBUG, "Accepted connection from %s", client_ip_address);
+    printf("Accepted connection from %s", client_ip_address);
+
+    // e. Receives data over the connection and appends to file /var/tmp/aesdsocketdata, creating this file if it doesn’t exist.
+    received_data_file_fd = open(RECEIVE_DATA_FILE, O_CREAT | O_APPEND | O_RDWR , 0644);    
+    memset(read_buffer, 0, RECEIVE_PACKET_SIZE);
+    while((number_of_bytes_read = recv(client_fd, read_buffer, RECEIVE_PACKET_SIZE, 0)) > 0)
+    {      
+      write(received_data_file_fd, read_buffer, number_of_bytes_read); 
+      // Your implementation should use a newline to separate data packets received.  
+      // In other words a packet is considered complete when a newline character is found in the input receive stream, 
+      // and each newline should result in an append to the /var/tmp/aesdsocketdata file.
+      if(strchr(read_buffer, '\n') != NULL) break;
+    }
+
+
+    // f. Returns the full content of /var/tmp/aesdsocketdata to the client as soon as the received data packet completes.
+    lseek(received_data_file_fd, 0, SEEK_SET);
+    while((number_of_bytes_sent = read(received_data_file_fd, read_buffer, RECEIVE_PACKET_SIZE)) > 0)
+    {
+      send(client_fd, read_buffer, number_of_bytes_sent, 0); 
+    }
+
+    // close the file descriptors
+    close(received_data_file_fd);
+    close(client_fd);
+
+    //g. Logs message to the syslog “Closed connection from XXX” where XXX is the IP address of the connected client.
+    syslog(LOG_DEBUG, "Closed connection from %s", client_ip_address);
+    printf("Closed connection from %s", client_ip_address);
+  }
+  return NO_ERROR;
+}
+
+
+void signal_handler(int signal_number)
+{
+  printf("Signal Received: %d \n", signal_number);
+ // i. Gracefully exits when SIGINT or SIGTERM is received, completing any open connection operations, closing any open sockets, and deleting the file /var/tmp/aesdsocketdata.
+  if((SIGINT==signal_number) || (SIGTERM==signal_number))
+  {
+    printf("caught signal exiting\n");
+    // Logs message to the syslog “Caught signal, exiting” when SIGINT or SIGTERM is received.
+    syslog(LOG_DEBUG, "Caught signal, exiting");  
+    close(server_fd);
+    close(client_fd);
+    remove(RECEIVE_DATA_FILE);
+    exit(1);
+  }
+}

server/aesdsocket.h

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+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <signal.h>
+#include <syslog.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/wait.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <netdb.h>
+#include <fcntl.h>
+#include <stdbool.h>
+
+//## MACROS
+#define ERROR -1
+#define NO_ERROR 0
+#define RECEIVE_PACKET_SIZE 1024
+#define PORT "9000"
+#define RECEIVE_DATA_FILE "/var/tmp/aesdsocketdata"
+#define LISTEN_BACKLOG 30

server/start-stop-daemon-aesdsocket

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+#!/bin/sh
+
+case "$1" in
+	start)
+		echo "Start aesdsocket daemon"
+		start-stop-daemon -S -n aesdsocket -a ./aesdsocket -- -d
+		;;
+	stop)
+		echo "Stop aesdsocket daemon"
+		start-stop-daemon -K -n aesdsocket
+		;;
+	*)
+		echo "Usage: $0 {start|stop}"
+	exit 1
+esac
+
+exit 0