int main(int argc, char **argv){
if(argc == 1){
fprintf(stderr, "copy: Missing arguments list\nTry 'copy -h' for help\n");
return 1;
}
int c;
int mflag = 0;
opterr = 0;
while((c = getopt(argc, argv, "hm")) != -1){ //if set "hm:" then -m requirs 1 argument and i have no idea how to force 2.
switch (c){
case 'h':
printf("Usage:\n");
printf(" copy <file_name> <new_file_name>\n");
printf(" copy [-m] <file_name> <new_file_name>\n");
return 0;
case 'm':
if(argc != 4){
fprintf(stderr, "copy: Option -m requires 2 arguments.\nTry 'copy -h' for help\n");
return 1;
}
mflag = 1;
break;
case '?':
if(isprint (optopt))
fprintf(stderr, "copy: Unknown option '-%c'\nTry 'copy -h' for help\n", optopt);
else
fprintf(stderr, "copy: Unknown option character `\\x%x`.\n", optopt);
return 1;
default:
fprintf(stderr, "copy: abort()");
abort();
}
} //while
//Possible cases:
//argc == 4 && mflag == 1
//argc == 3 && mflag == 0
if(argc != 3 && mflag == 0){
fprintf(stderr, "copy: Wrong arguments list\nTry 'copy -h' for help\n");
return 1;
}
int fd_from, fd_to; //declaring file descriptors
if((fd_from = open(argv[mflag+1], O_RDONLY)) == -1 || (fd_to = open(argv[mflag+2], O_RDWR | O_CREAT, 0666)) == -1){ //O_RDWD
perror("open");
return 1;
}
if(mflag == 0) //without -m option
copy_read_write(fd_from, fd_to);
else
copy_mmap(fd_from, fd_to);
close(fd_from);
close(fd_to);
return 0;
}
int main(int argc, char *argv[])
{
int in, out, mode, res = EXIT_FAILURE;
// make sure the user provided the necessary command line arguments
if (argc != 4) {
fprintf(stderr, "Usage: %s <source> <dest> <mode>\n"
"\n"
"Copies a file from <source> to <dest>.\n"
"<mode> must be either 1 or 2 where\n"
" mode==%d use buffer copy algorithm\n"
" mode==%d use mmap copy algorithm\n",
argv[0], M_BUFFER, M_MMAP);
exit(EXIT_FAILURE);
}
// first check the mode
mode = atoi(argv[3]);
if (!((mode == M_BUFFER) || (mode == M_MMAP))) {
fprintf(stderr, "Invalid copy mode specified (%d)\n", mode);
exit(EXIT_FAILURE);
}
// open the source file read-only and check for errors
in = open(argv[1], O_RDONLY);
if (in == -1) {
perror("Error opening input file");
exit(EXIT_FAILURE);
}
// check if output file exists and abort if yes
if (access(argv[2], F_OK) == 0) {
fprintf(stderr, "Cowardly refusing to overwrite an exiting file\n");
exit(EXIT_FAILURE);
}
// open the destination file write-only and check for errors
out = open(argv[2], O_CREAT|O_TRUNC|O_WRONLY,S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH);
if (out == -1) {
perror("Error opening output file");
exit(EXIT_FAILURE);
}
// invoke file copy
switch (mode) {
case M_BUFFER: res = copy_buffer(in, out);
break;
case M_MMAP: res = copy_mmap(in, out);
break;
}
// close source & destination
close(in);
close(out);
return res;
}
