Programming

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#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

int main(void)
{
  ssize_t bytes;
  char buf[512];
  int fd=open("path/to/file", O_RDONLY);
  if(fd < 0)
  {
    perror("Couldn't open file");
    return(1);
  }

  bytes=read(fd, buf, 512);
  if(bytes <= 0)
  {
    perror("Couldn't read");
    close(fd);
    return(2);
  }

  close(file);


  // You now have 'bytes' bytes of data read into the buffer 'buf'.

  // Do other stuff here

  return(0);
}

    struct stat sb;
    off_t offset = 0L;
    int fd;

    fd = open( filename, O_RDONLY );
    fstat( fd, &sb );
    sendfile( socket_fd, fd, &offset, sb.st_size );
    close( fd );

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <fcntl.h>
#include <netinet/in.h>
#include <linux/if_ether.h>
#include <sys/stat.h>

int main(int argc, char *argv[])
{
if(argc !=3){
printf("Usage: %s <iface> <raw filename>\n", argv[0]);
exit(1);
}

int sfd,ffd;
ssize_t bytes;
unsigned char *buffer;
struct stat sizb;
struct sockaddr from;
from.sa_family = 1;
strcpy(from.sa_data, argv[1]);

if((stat(argv[2],&sizb))!=0){
perror("stat() failed: ");
exit(1);
}

buffer=(unsigned char *)malloc(sizb.st_size);
if((ffd=open(argv[2], O_RDONLY))<0){
perror("open() failed: ");
exit(1);
}

if((bytes = read(ffd, buffer, sizb.st_size))<= 0){
perror("read() failed: ");
close(ffd);
exit(1);
} else {
close(ffd);
}

if((sfd=socket(AF_INET,SOCK_PACKET,ntohs(ETH_P_ALL)))<0){
perror("socket() failed: ");
exit(1);
}

if((sendto(sfd, buffer, sizb.st_size,0,(struct sockaddr *)&from,sizeof(from)))<0){
perror("send() failed: ");
exit(1);
}

printf("%i bytes transmitted.\n", sizb.st_size);
close(sfd);
return 0;
}

#include <stdio.h>

int main(void)
{
  size_t bytes;
  char buf[512];
  FILE *fp=fopen("filename", "rb");
  if(fp == NULL)
  {
    fprintf(stderr, "Couldn't open file\n");
    return(1);
  }

  bytes=fread(buf, 1, 512, fp);
  if(bytes <= 0)
  {
    fprintf(stderr, "Couldn't read from file\n");
    fclose(fp);
    return(2);
  }
  fclose(fp);
  fprintf(stderr, "Read %d bytes into buffer\n", bytes);


  return(0);
}