1 /* mkswap.c - Format swap device.
2 *
3 * Copyright 2009 Rob Landley <rob@landley.net>
4
5 USE_MKSWAP(NEWTOY(mkswap, "<1>1L:", TOYFLAG_SBIN))
6
7 config MKSWAP
8 bool "mkswap"
9 default y
10 help
11 usage: mkswap [-L LABEL] DEVICE
12
13 Sets up a Linux swap area on a device or file.
14 */
15
16 #define FOR_mkswap
17 #include "toys.h"
18
GLOBALS(char * L;)19 GLOBALS(
20 char *L;
21 )
22
23 void 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