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