Thread: Send a message after sending a file via socket

Hello,
I made a program that transfers a JSON file using the client's socket to the server. In fact, I wanted to send a message after receiving the file from the server to the client but apparently there is a problem that is wrong, so the message does not arrive at the client. Can you help me please. Here are the source codes:
server.c

Code:

#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <json-c/json.h>
#include <netinet/in.h> 
#include <pthread.h>
#include <stdio.h> 
#include <stdlib.h>
#include <string.h> 
#include <stdarg.h>
#include <sys/mman.h> 
#include <sys/stat.h>
#include <sys/socket.h> 
#include <unistd.h> 
#include "jsmn.h"
 
#define BUFFER_SIZE          1024
#define MARGE_PROGRESSION     100
#define BUFFER_SIZE_JSON   100000
#define MAX_TOKEN_COUNT       128
 
pthread_t        th_server;
pthread_cond_t   cond_sr;
pthread_mutex_t  verrou_sr;
 
/***********************************************************************
 * Main.c: 
 **********************************************************************/
int main(int argc, char *argv[]) 
{ 
  FILE* fichier_sr;
  int   socket         = 0;
  int   size_line, desc_write;
  long  fichier_size   = 0, size_avanc_sr = 0;
  char* fichier_sr_nom = "server_test.json";
  char* line_buf       = (char *) malloc (BUFFER_SIZE*sizeof(char));
  char* Msg_to_cl      = (char* )malloc(BUFFER_SIZE*sizeof(char));  
        Msg_to_cl      = "hello from server\n";  
  pthread_mutex_init (&verrou_sr, NULL); 
  pthread_cond_init (&cond_sr, NULL);
 
  fichier_sr   = fopen(fichier_sr_nom,"w");
  socket       = attente (socket, argv[1]);
  fichier_size = lire_taille_fich(socket, fichier_size);   
 
  pthread_create(&th_server,NULL,thread_pourcentage_server,NULL);
 
  while((size_line = recevoir_fichier(size_line,socket, line_buf)) >= 0) 
  { 
    if (size_line == 0) 
	{
	  break;
	}
	desc_write = ecrire_fichier(desc_write,size_line,fichier_sr,line_buf);
	size_avanc_sr += size_line;
	pthread_mutex_lock(&verrou_sr);
	result_server=100*((float)(size_avanc_sr)/(float)(fichier_size));
	pthread_mutex_unlock(&verrou_sr);
	pthread_cond_broadcast(&cond_sr);
    usleep(100000);
 
	if (desc_write < size_line)
	{
	  perror("File write failed on server.\n");
	}
  }
  pthread_join(th_server, NULL);   
  pthread_mutex_destroy (&verrou_sr);
  pthread_cond_destroy (&cond_sr); 
  fclose(fichier_sr);
  //parseJSON(fichier_sr_nom);
  send(socket,Msg_to_cl,BUFFER_SIZE,0);
  return 0;
}

client.c

Code:

#include <arpa/inet.h>
#include <stdio.h> 
#include <unistd.h>
#include <sys/socket.h> 
#include <stdlib.h> 
#include <netinet/in.h> 
#include <string.h> 
#include <sys/stat.h>
#include <pthread.h>
 
#define BUFFER_SIZE      1024
#define MARGE_PROGRESSION 100
 
pthread_t        th_client;
pthread_cond_t   cond_cl;
pthread_mutex_t  verrou_cl;
 
/***********************************************************************
 * Main.c: 
 **********************************************************************/
int main(int argc, char *argv[]) 
{  
  FILE*    fichier_cl;
  int      socket = 0;
  long     size_file     = 0, size_avanc_cl = 0;
  char*    line_str      = NULL;
  char*    file_name     = "client_file.json";
  char*    Msg_from_sr   = (char* )malloc(BUFFER_SIZE*sizeof(char));            
  size_t   line_pos      = 0;
  ssize_t  desc_line;
 
  pthread_mutex_init (&verrou_cl, NULL); 
  pthread_cond_init (&cond_cl, NULL);
 
  fichier_cl = fopen(file_name,"r");
  size_file  = taille_fich(file_name);
 
  socket     = connecte(socket,argv[1],argv[2]);
  socket     = envoyer_taille_fich(socket,size_file);
  pthread_create(&th_client,NULL,thread_pourcentage_client,NULL);
 
  while ((desc_line = getline(&line_str, &line_pos, fichier_cl)) != -1) 
  {
    if((socket = envoyer_fich(socket,line_str)) < 0) 
	{
	  printf("ERROR: Failed to send file %s.\n", file_name);
	  break;
	}
	size_avanc_cl += strlen(line_str);
	pthread_mutex_lock(&verrou_cl);
	result_thread=100*((float)(size_avanc_cl)/(float)(size_file));
	pthread_mutex_unlock(&verrou_cl);
	pthread_cond_broadcast(&cond_cl);
    //usleep(100000);
 
    if (line_str)
    {
    free(line_str);
    }
    line_pos = 0;  
  }
  pthread_join(th_client, NULL);   
  pthread_mutex_destroy (&verrou_cl);
  pthread_cond_destroy (&cond_cl);
  fclose(fichier_cl);
  read(socket, Msg_from_sr, 100);
  return 0; 
}