#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/stat.h>

#include "memfd.h"
#include "ipc_msg.h"

int g_memfd = 0;

void handler(){

  printf("clean program start\n");
  //unlink(UNIX_DOMAIN);
  remove(UNIX_DOMAIN);
  printf("clean end.\n");
}

int shm_write(int fd)
{
  struct stat st;
  ssize_t len;
  int ret = 0;  
  unsigned char* paddr;

  if (fstat (fd, &st))
    errExit ("fstat");
  len = st.st_size;

  char *content = "hello world!\n";
  ret =  basic_shm_mmap (fd, &paddr);
  if (ret < 0)
    errExit("basic_shm_mmap");

  memcpy(paddr, content, strlen(content));

  printf("length: %zu, atime: %lu.%lu\n", len, st.st_atim.tv_sec, st.st_atim.tv_nsec);
  return len;
}



int proc_memfd(struct user_data* rdata)
{
    int fd = rdata->fd;
    unsigned int n_size;
    char line[MAX_LEN]= {0};
    int n = 0;
    int nwrite = 0;
    int data_size = 0;    
    memfd_data_st memfd_data = {0};

    if(rdata->n_size <= 0 || fd < 0)
    {
      return -1;
    }

    if(0 == strncmp(rdata->line, HELLO_MSG, strlen(HELLO_MSG)))
    {
      memfd_data.memfd = g_memfd;
      memfd_data.pid = getpid();
      memfd_data.data = NULL;
      memfd_data.len = 0;
      data_size = sizeof(memfd_data_st) + memfd_data.len;
      memcpy(line, &memfd_data, data_size);
    }
    else
    {
      return  -1;
    }
    
    n = data_size;
    while(n>0)
    {
        nwrite = write(rdata->fd, line+data_size-n,n);////ET
        if( nwrite < n )
        {
            if((nwrite==-1) && (errno != EAGAIN))
            {
                perror("write error");                
            }
            if (errno == ECONNRESET)
            {
                close(rdata->fd);
                printf("[SERVER] Error: send responce failed: %s\n", strerror(errno)); 
            }
            else if (nwrite == 0)
            {
                close(rdata->fd);
                printf("[SERVER] Error: client closed connection.");                  
            }
            break;
        }
        n -= nwrite;
    }

    return nwrite;
    
}

/*define you our proc_memfd funtion to send your message to other processes，or just put it in shm，
 notice the file description fd and the pid of creator to other*/
int main(int argc, char **argv)
{
  char *name;
  ssize_t  len;
  char * unixdomain = NULL;
  int ret = 0;

  if (argc < 3) {
    fprintf(stderr, "%s name size [unix domain path]\n", argv[0]);
    exit(EXIT_FAILURE);
  }

  name = argv[1];
  len = atoi(argv[2]) * 1024LU * 1024LU * 1024LU;
  unixdomain = argv[3];

  signal(SIGTERM,handler);
  signal(SIGABRT,handler);
  signal(SIGSEGV,handler);
  
 
  g_memfd = basic_shm_create(name, len);
  ret = shm_write(g_memfd);

  ret = basic_create_ipc_server(unixdomain);
  if(ret < 0)
  {
     printf("failed to create ipc_server\n");      
  }

  basic_shm_close(g_memfd);  
  return 0;
}