mmap to implement copy command

/*

Program to Implement copy using mmap

*/

#include

#include

#include

#include

#include

#include

#include

#include

struct stat statbuf;

int main(int argc, char *argv[]) {

int fdin, fdout, ret;

char *src, *dest;

if(argc < 3) {

printf("\n Check number of arguments\n");

exit(EXIT_FAILURE);

}

fdin = open(argv[1], O_RDONLY);

if(fdin < 0) {

printf("\n Cant open source file \n");

exit(EXIT_FAILURE);

}

ret=fstat(fdin,&statbuf);

if(ret < 0 ) {

printf("\nfstat system call failed ");

exit(EXIT_FAILURE);

}

printf("\nInpute File size is - %lu ",statbuf.st_size);

src=(char*)mmap(0, statbuf.st_size, PROT_READ, MAP_SHARED, fdin,0);

fdout = open(argv[2],O_RDWR | O_CREAT | O_TRUNC,S_IRWXU | S_IRWXO);

if(fdout < 0) {

printf("\n Cant open source file");

exit(EXIT_FAILURE);

}

ret=lseek(fdout,statbuf.st_size-1,SEEK_SET);

if(ret < 0)

printf("\n lseek failed ");

ret=write(fdout,"",1);

if(ret < 0)

printf("\n write failed ");

dest=(char *)mmap(0, statbuf.st_size, PROT_READ | PROT_WRITE, MAP_SHARED, fdout,0);

dest=memcpy(dest,src,statbuf.st_size);

if(!dest)

printf("\n memcpy failed ");

// msync((void *)dest,statbuf.st_size,MS_ASYNC);

printf("\nFile copied succefully\n");

printf("\n");

}