Copy file using C & Threads

Creating a copy program in c using threads

This program will break the big file in smaller chunks and then uses dedicated threads to copy the data of that particular chunk from the source to the target. As a result we can copy the file of big sizes by making the use of parallelism.

Here is the code.

#include <fcntl.h>
#include <pthread.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <stdio.h>
#include <string.h>

#define SIZE 4096

typedef struct{
	unsigned long offset;
	unsigned long size;

char file[50]; /* source file name */
char fileout[50]; /* target file name */

void* func1(void *arg);

int main(int argc, char *argv[]){
	char 		data[SIZE];
	struct stat 	f_stat;
	int 		fin1, fout1, x, chk, i=0;
	PART 		part1, part2, part3;
	pthread_t 	t1, t2; // two threads to share the load of main thread
	if(argc < 3){
		puts("Not enough arguments.");
		puts("parallelCopy sourceFile targetFile");
		return -1;
	strcpy(file, argv[1]);
	stat(file, &f_stat); 	// getting the meta info of file
	strcpy(fileout, argv[2]);

	printf("Size of file is %lu \n", f_stat.st_size);
	part1.offset = 0;

	// dividing the size of file in 3 parts
	part1.size = f_stat.st_size / 3; 
	part2.offset = part1.size;
	part2.size = part1.size;
	part3.offset = part2.offset + part2.size;
	part3.size = f_stat.st_size - part3.offset;

	/* creating part1 by main thread */
	fin1 = open(file, O_RDONLY);
	fout1 = open(fileout, O_WRONLY|O_CREAT, 0666);

	/*creating 3 threads to copy 2 n 3rd part of file */
        pthread_create(&t1, NULL, func1, &part2);
	pthread_create(&t2, NULL, func1, &part3);

	while(i < part1.size){	
		x = read(fin1, data, SIZE);
		write(fout1, data, x);
		i += x;
	pthread_join(t1, NULL); // making main to wait for t1
	pthread_join(t2, NULL); // making main to wait for t2
	printf("file is copied");
	return 0;

void* func1(void *arg){
	int fin, fout, x, i;
	PART *part;
	char data[SIZE];
	part = (PART *)arg;
	fin = open(file, O_RDONLY);
        fout = open(fileout, O_WRONLY);
	lseek(fin, part->offset, SEEK_SET);
	lseek(fout, part->offset, SEEK_SET);
        while(i < part->size){
                x = read(fin, data, SIZE);
                write(fout, data, x);
                i += x;
        printf("thread is done.\n");

After this we need to compile the code using gcc in linux

 gcc parallelCopy.c -o parallelCopy -lpthread 

Note here we need to reference the pthread library while compilation

After this we can use to copy a file from one place to other by passing the name of source file and target file as arguments. It will make use of threads and copy the file using parallelism.

$ ./parallelCopy SourceFile TargetFile

In this way we implement threads to copy file using C language in Linux System.

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