Linux cp command implementation to copy multiple files to a Directory - c

Question

I'm currently learning systems programming and came across an implementation of the Linux cp command in C. This implementation though from my understanding allows for copying the contents of one file to another file in the same directory and also copying a file into a Directory in the current directory.
How could you change this code to allow for multiple files to be copied to a directory at once (i.e "copy f1.txt f2.txt f3.txt /dirInCurrentDir")
or even ("copy d1/d2/d3/f1 d4/d5/d6/f2 d ") which would copy the 2 files to directory d. I know that the changes would have to occur in main() but how could you add to the if-else statement?
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <dirent.h>
#include <sys/types.h>
#include <sys/stat.h>
#define BUFFERSIZE 1024
#define COPYMORE 0644
void oops(char *, char *);
int copyFiles(char *src, char *dest);
int dostat(char *filename);
int mode_isReg(struct stat info);
int main(int ac, char *av[])
{
/* checks args */
if(ac != 3)
{
fprintf(stderr, "usage: %s source destination\n", *av);
exit(1);
}
char *src = av[1];
char *dest = av[2];
if( src[0] != '/' && dest[0] != '/' )//cp1 file1.txt file2.txt
{
copyFiles(src, dest);
}
else if( src[0] != '/' && dest[0] == '/' )//cp1 file1.txt /dir
{
int i;
for(i=1; i<=strlen(dest); i++)
{
dest[(i-1)] = dest[i];
}
strcat(dest, "/");
strcat(dest, src);
copyFiles(src, dest);
}
else
{
fprintf(stderr, "usage: cp1 source destination\n");
exit(1);
}
}
int dostat(char *filename)
{
struct stat fileInfo;
//printf("Next File %s\n", filename);
if(stat(filename, &fileInfo) >=0)
if(S_ISREG(fileInfo.st_mode))
return 1;
else return 0;
return;
}
int copyFiles(char *source, char *destination)
{
int in_fd, out_fd, n_chars;
char buf[BUFFERSIZE];
/* open files */
if( (in_fd=open(source, O_RDONLY)) == -1 )
{
oops("Cannot open ", source);
}
if( (out_fd=creat(destination, COPYMORE)) == -1 )
{
oops("Cannot create ", destination);
}
/* copy files */
while( (n_chars = read(in_fd, buf, BUFFERSIZE)) > 0 )
{
if( write(out_fd, buf, n_chars) != n_chars )
{
oops("Write error to ", destination);
}
if( n_chars == -1 )
{
oops("Read error from ", source);
}
}
/* close files */
if( close(in_fd) == -1 || close(out_fd) == -1 )
{
oops("Error closing files", "");
}
return 1;
}
void oops(char *s1, char *s2)
{
fprintf(stderr, "Error: %s ", s1);
perror(s2);
exit(1);
}

Answer 1

You would loop through all the argument values (from av[1] to av[ac - 2]) and copy it to the destination argument, which would be av[ac - 1].
In your case, you would pass av[i] and av[ac - 1] to the copyFiles function, where i would be your loop index.