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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include "cow.h"
void usage(const char progname[])
{
fprintf(stderr, "%s usage: \n", progname);
fprintf(stderr, "\t%s [-f] <COW file> <backing file>\n", progname);
fprintf(stderr, "\t-f forces overwrite of an existing COW file\n");
exit(2);
}
int main(int argc, char *argv[])
{
int fd;
int err;
char *cow_file;
char *backing_file;
int bitmap_offset_out;
unsigned long bitmap_len_out;
int data_offset_out;
int flags;
mode_t mode;
char *progname;
progname = argv[0];
argv++;
argc--;
if(argc < 1)
usage(progname);
flags = O_RDWR | O_CREAT | O_LARGEFILE;
mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH;
if(strcmp("-f", argv[0]) != 0){
/* not forced, creating as exclusive */
flags |= O_EXCL;
}
else {
argv++;
argc--;
}
if (argc < 2)
usage(progname);
cow_file = argv[0];
backing_file = argv[1];
if((fd = open(cow_file, flags, mode)) == -1) {
perror("open COW file");
exit(1);
}
if((err = init_cow_file(fd, cow_file, backing_file, 512, sysconf(_SC_PAGESIZE),
&bitmap_offset_out, &bitmap_len_out, &data_offset_out))){
errno = -err;
perror("write_cow_header");
exit(1);
}
return (0);
}
/* vim: ts=4 tw=74 sw=2
*/
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