LXR toybox/toys/other/mkswap.c

   1/* mkswap.c - Format swap device.
   2 *
   3 * Copyright 2009 Rob Landley <rob@landley.net>
   4
   5USE_MKSWAP(NEWTOY(mkswap, "<1>1L:", TOYFLAG_SBIN))
   6
   7config MKSWAP
   8  bool "mkswap"
   9  default y
  10  help
  11    usage: mkswap [-L LABEL] DEVICE
  12
  13    Set up a Linux swap area on a device or file.
  14*/
  15
  16#define FOR_mkswap
  17#include "toys.h"
  18
  19GLOBALS(
  20  char *L;
  21)
  22
  23void mkswap_main(void)
  24{
  25  int fd = xopen(*toys.optargs, O_RDWR), pagesize = sysconf(_SC_PAGE_SIZE);
  26  off_t len = fdlength(fd);
  27  unsigned int pages = (len/pagesize)-1, *swap = (unsigned int *)toybuf;
  28  char *label = (char *)(swap+7), *uuid = (char *)(swap+3);
  29
  30  // Write header. Note that older kernel versions checked signature
  31  // on disk (not in cache) during swapon, so sync after writing.
  32
  33  swap[0] = 1;
  34  swap[1] = pages;
  35  xlseek(fd, 1024, SEEK_SET);
  36  create_uuid(uuid);
  37  if (TT.L) strncpy(label, TT.L, 15);
  38  xwrite(fd, swap, 129*sizeof(unsigned int));
  39  xlseek(fd, pagesize-10, SEEK_SET);
  40  xwrite(fd, "SWAPSPACE2", 10);
  41  fsync(fd);
  42
  43  if (CFG_TOYBOX_FREE) close(fd);
  44
  45  if (TT.L) sprintf(toybuf, ", LABEL=%s", label);
  46  else *toybuf = 0;
  47  printf("Swapspace size: %luk%s, UUID=%s\n",
  48    pages*(unsigned long)(pagesize/1024),
  49    toybuf, show_uuid(uuid));
  50}
  51