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/* vi: set sw=4 ts=4: */
/* mkswap.c - format swap device (Linux v1 only)
*
* Copyright 2006 Rob Landley <rob@landley.net>
*
* Licensed under GPL version 2, see file LICENSE in this tarball for details.
*/
#include "busybox.h"
int mkswap_main(int argc, char **argv);
int mkswap_main(int argc, char **argv)
{
int fd, pagesize;
off_t len;
unsigned int hdr[129];
// No options supported.
if (argc != 2) bb_show_usage();
// Figure out how big the device is and announce our intentions.
fd = xopen(argv[1], O_RDWR);
len = fdlength(fd);
pagesize = getpagesize();
printf("Setting up swapspace version 1, size = %"OFF_FMT"d bytes\n",
len - pagesize);
// Make a header.
memset(hdr, 0, sizeof(hdr));
hdr[0] = 1;
hdr[1] = (len / pagesize) - 1;
// Write the header. Sync to disk because some kernel versions check
// signature on disk (not in cache) during swapon.
xlseek(fd, 1024, SEEK_SET);
xwrite(fd, hdr, sizeof(hdr));
xlseek(fd, pagesize-10, SEEK_SET);
xwrite(fd, "SWAPSPACE2", 10);
fsync(fd);
if (ENABLE_FEATURE_CLEAN_UP) close(fd);
return 0;
}
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