/*
* mkswap.c - set up a linux swap device
*
* (C) 1991 Linus Torvalds. This file may be redistributed as per
* the Linux copyright.
*/
/*
* 20.12.91 - time began. Got VM working yesterday by doing this by hand.
*
* Usage: mkswap [-c] [-vN] [-f] device [size-in-blocks]
*
* -c for readability checking. (Use it unless you are SURE!)
* -vN for swap areas version N. (Only N=0,1 known today.)
* -f for forcing swap creation even if it would smash partition table.
*
* The device may be a block device or an image of one, but this isn't
* enforced (but it's not much fun on a character device :-).
*
* Patches from jaggy@purplet.demon.co.uk (Mike Jagdis) to make the
* size-in-blocks parameter optional added Wed Feb 8 10:33:43 1995.
*
* Version 1 swap area code (for kernel 2.1.117), aeb, 981010.
*
* Sparc fixes, jj@ultra.linux.cz (Jakub Jelinek), 981201 - mangled by aeb.
* V1_MAX_PAGES fixes, jj, 990325.
* sparc64 fixes, jj, 000219.
*
* 1999-02-22 Arkadiusz Mi¶kiewicz <misiek@pld.ORG.PL>
* - added Native Language Support
*
*/
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <fcntl.h>
#include <stdlib.h>
#include <limits.h>
#include <mntent.h>
#include <sys/utsname.h>
#include <sys/stat.h>
#include <errno.h>
#ifdef HAVE_LIBSELINUX
#include <selinux/selinux.h>
#include <selinux/context.h>
#endif
#include "linux_version.h"
#include "swapheader.h"
#include "xstrncpy.h"
#include "nls.h"
#include "blkdev.h"
#include "pathnames.h"
#include "wholedisk.h"
#include "writeall.h"
#ifdef HAVE_LIBUUID
# ifdef HAVE_UUID_UUID_H
# include <uuid/uuid.h>
# else
# include <uuid.h>
# endif
#endif
#ifdef HAVE_LIBBLKID_INTERNAL
# include <blkid.h>
#endif
static char * program_name = "mkswap";
static char * device_name = NULL;
static int DEV = -1;
static unsigned long long PAGES = 0;
static unsigned long badpages = 0;
static int check = 0;
#define SELINUX_SWAPFILE_TYPE "swapfile_t"
#ifdef __sparc__
# ifdef __arch64__
# define is_sparc64() 1
# define is_be64() 1
# else /* sparc32 */
static int
is_sparc64(void) {
struct utsname un;
static int sparc64 = -1;
if (sparc64 != -1) return sparc64;
sparc64 = 0;
if (uname(&un) < 0) return 0;
if (! strcmp(un.machine, "sparc64")) {
sparc64 = 1;
return 1;
}
if (strcmp(un.machine, "sparc"))
return 0; /* Should not happen */
#ifdef HAVE_PERSONALITY
{
extern int personality(unsigned long);
int oldpers;
#define PERS_LINUX 0x00000000
#define PERS_LINUX_32BIT 0x00800000
#define PERS_LINUX32 0x00000008
oldpers = personality(PERS_LINUX_32BIT);
if (oldpers != -1) {
if (personality(PERS_LINUX) != -1) {
uname(&un);
if (! strcmp(un.machine, "sparc64")) {
sparc64 = 1;
oldpers = PERS_LINUX32;
}
}
personality(oldpers);
}
}
#endif
return sparc64;
}
# define is_be64() is_sparc64()
# endif /* sparc32 */
#else /* !sparc */
# define is_be64() 0
#endif
/*
* The definition of the union swap_header uses the kernel constant PAGE_SIZE.
* Unfortunately, on some architectures this depends on the hardware model, and
* can only be found at run time -- we use getpagesize(), so that we do not
* need separate binaries e.g. for sun4, sun4c/d/m and sun4u.
*
* Even more unfortunately, getpagesize() does not always return the right
* information. For example, libc4, libc5 and glibc 2.0 do not use the system
* call but invent a value themselves (EXEC_PAGESIZE or NBPG * CLSIZE or NBPC),
* and thus it may happen that e.g. on a sparc kernel PAGE_SIZE=4096 and
* getpagesize() returns 8192.
*
* What to do? Let us allow the user to specify the pagesize explicitly.
*
*/
static int user_pagesize;
static int pagesize;
static unsigned long *signature_page = NULL;
static void
init_signature_page(void) {
int kernel_pagesize = pagesize = getpagesize();
if (user_pagesize) {
if ((user_pagesize & (user_pagesize-1)) ||
user_pagesize < sizeof(struct swap_header_v1_2) + 10) {
fprintf(stderr, _("Bad user-specified page size %d\n"),
user_pagesize);
exit(1);
}
pagesize = user_pagesize;
}
if (user_pagesize && user_pagesize != kernel_pagesize)
fprintf(stderr, _("Using user-specified page size %d, "
"instead of the system value %d\n"),
pagesize, kernel_pagesize);
signature_page = (unsigned long *) calloc(1, pagesize);
if (!signature_page) {
fprintf(stderr, _("%s: calloc() failed: %s\n"),
program_name, strerror(errno));
exit(1);
}
}
static void
write_signature(char *sig) {
char *sp = (char *) signature_page;
strncpy(sp+pagesize-10, sig, 10);
}
static void
write_uuid_and_label(unsigned char *uuid, char *volume_name) {
struct swap_header_v1_2 *h;
/* Sanity check */
if (sizeof(struct swap_header_v1) !=
sizeof(struct swap_header_v1_2)) {
fprintf(stderr,
_("Bad swap header size, no label written.\n"));
return;
}
h = (struct swap_header_v1_2 *) signature_page;
if (uuid)
memcpy(h->uuid, uuid, sizeof(h->uuid));
if (volume_name) {
xstrncpy(h->volume_name, volume_name, sizeof(h->volume_name));
if (strlen(volume_name) > strlen(h->volume_name))
fprintf(stderr, _("Label was truncated.\n"));
}
if (uuid || volume_name) {
if (volume_name)
printf("LABEL=%s, ", h->volume_name);
else
printf(_("no label, "));
#ifdef HAVE_LIBUUID
if (uuid) {
char uuid_string[37];
uuid_unparse(uuid, uuid_string);
printf("UUID=%s\n", uuid_string);
} else
#endif
printf(_("no uuid\n"));
}
}
/*
* Find out what the maximum amount of swap space is that the kernel will
* handle. This wouldn't matter if the kernel just used as much of the
* swap space as it can handle, but until 2.3.4 it would return an error
* to swapon() if the swapspace was too large.
*/
/* Before 2.2.0pre9 */
#define V1_OLD_MAX_PAGES ((0x7fffffff / pagesize) - 1)
/* Since 2.2.0pre9, before 2.3.4:
error if nr of pages >= SWP_OFFSET(SWP_ENTRY(0,~0UL))
with variations on
#define SWP_ENTRY(type,offset) (((type) << 1) | ((offset) << 8))
#define SWP_OFFSET(entry) ((entry) >> 8)
on the various architectures. Below the result - yuk.
Machine pagesize SWP_ENTRY SWP_OFFSET bound+1 oldbound+2
i386 2^12 o<<8 e>>8 1<<24 1<<19
mips 2^12 o<<15 e>>15 1<<17 1<<19
alpha 2^13 o<<40 e>>40 1<<24 1<<18
m68k 2^12 o<<12 e>>12 1<<20 1<<19
sparc 2^{12,13} (o&0x3ffff)<<9 (e>>9)&0x3ffff 1<<18 1<<{19,18}
sparc64 2^13 o<<13 e>>13 1<<51 1<<18
ppc 2^12 o<<8 e>>8 1<<24 1<<19
armo 2^{13,14,15} o<<8 e>>8 1<<24 1<<{18,17,16}
armv 2^12 o<<9 e>>9 1<<23 1<<19
assuming that longs have 64 bits on alpha and sparc64 and 32 bits elsewhere.
The bad part is that we need to know this since the kernel will
refuse a swap space if it is too large.
*/
/* patch from jj - why does this differ from the above? */
/* 32bit kernels have a second limitation of 2GB, sparc64 is limited by
the size of virtual address space allocation for vmalloc */
#if defined(__alpha__)
#define V1_MAX_PAGES ((1 << 24) - 1)
#elif defined(__mips__)
#define V1_MAX_PAGES ((1 << 17) - 1)
#elif defined(__sparc__)
#define V1_MAX_PAGES (is_sparc64() ? ((3 << 29) - 1) : ((1 << 18) - 1))
#elif defined(__ia64__)
/*
* The actual size will depend on the amount of virtual address space
* available to vmalloc the swap map.
*/
#define V1_MAX_PAGES ((1UL << 54) - 1)
#else
#define V1_MAX_PAGES V1_OLD_MAX_PAGES
#endif
/* man page now says:
The maximum useful size of a swap area now depends on the architecture.
It is roughly 2GB on i386, PPC, m68k, ARM, 1GB on sparc, 512MB on mips,
128GB on alpha and 3TB on sparc64.
*/
#define MAX_BADPAGES ((pagesize-1024-128*sizeof(int)-10)/sizeof(int))
#define MIN_GOODPAGES 10
static void
usage(void) {
fprintf(stderr,
_("Usage: %s [-c] [-pPAGESZ] [-L label] [-U UUID] /dev/name [blocks]\n"),
program_name);
exit(1);
}
static void
die(const char *str) {
fprintf(stderr, "%s: %s\n", program_name, str);
exit(1);
}
static void
page_bad(int page) {
struct swap_header_v1_2 *p = (struct swap_header_v1_2 *) signature_page;
if (badpages == MAX_BADPAGES)
die(_("too many bad pages"));
p->badpages[badpages] = page;
badpages++;
}
static void
check_blocks(void) {
unsigned int current_page;
int do_seek = 1;
char *buffer;
buffer = malloc(pagesize);
if (!buffer)
die(_("Out of memory"));
current_page = 0;
while (current_page < PAGES) {
if (do_seek && lseek(DEV,current_page*pagesize,SEEK_SET) !=
current_page*pagesize)
die(_("seek failed in check_blocks"));
if ((do_seek = (pagesize != read(DEV, buffer, pagesize))))
page_bad(current_page);
current_page++;
}
if (badpages == 1)
printf(_("one bad page\n"));
else if (badpages > 1)
printf(_("%lu bad pages\n"), badpages);
free(buffer);
}
/* return size in pages */
static unsigned long long
get_size(const char *file) {
int fd;
unsigned long long size;
fd = open(file, O_RDONLY);
if (fd < 0) {
perror(file);
exit(1);
}
if (blkdev_get_size(fd, &size) == 0)
size /= pagesize;
close(fd);
return size;
}
static int
isnzdigit(char c) {
return (c >= '1' && c <= '9');
}
/*
* Check to make certain that our new filesystem won't be created on
* an already mounted partition. Code adapted from mke2fs, Copyright
* (C) 1994 Theodore Ts'o. Also licensed under GPL.
* (C) 2006 Karel Zak -- port to mkswap
*/
static int
check_mount(void) {
FILE * f;
struct mntent * mnt;
if ((f = setmntent (_PATH_MOUNTED, "r")) == NULL)
return 0;
while ((mnt = getmntent (f)) != NULL)
if (strcmp (device_name, mnt->mnt_fsname) == 0)
break;
endmntent (f);
if (!mnt)
return 0;
return 1;
}
static void
zap_bootbits(int fd, const char *devname, int force, int is_blkdev)
{
char *type = NULL;
int whole = 0;
int zap = 1;
if (!force) {
if (lseek(fd, 0, SEEK_SET) != 0)
die(_("unable to rewind swap-device"));
if (is_blkdev && is_whole_disk_fd(fd, devname)) {
/* don't zap bootbits on whole disk -- we know nothing
* about bootloaders on the device */
whole = 1;
zap = 0;
} else {
#ifdef HAVE_LIBBLKID_INTERNAL
blkid_probe pr = blkid_new_probe();
if (!pr)
die(_("unable to alloc new libblkid probe"));
if (blkid_probe_set_device(pr, fd, 0, 0))
die(_("unable to assign device to libblkid probe"));
blkid_probe_enable_partitions(pr, 1);
blkid_probe_enable_superblocks(pr, 0);
if (blkid_do_fullprobe(pr) == 0)
blkid_probe_lookup_value(pr, "PTTYPE",
(const char **) &type, NULL);
if (type) {
type = strdup(type);
zap = 0;
}
blkid_free_probe(pr);
#else
/* don't zap if compiled without libblkid */
zap = 0;
#endif
}
}
if (zap) {
char buf[1024];
if (lseek(fd, 0, SEEK_SET) != 0)
die(_("unable to rewind swap-device"));
memset(buf, 0, sizeof(buf));
if (write_all(fd, buf, sizeof(buf)))
die(_("unable to erase bootbits sectors"));
return;
}
fprintf(stderr, _("%s: %s: warning: don't erase bootbits sectors\n"),
program_name, devname);
if (type)
fprintf(stderr, _(" (%s partition table detected). "), type);
else if (whole)
fprintf(stderr, _(" on whole disk. "));
else
fprintf(stderr, _(" (compiled without libblkid). "));
fprintf(stderr, "Use -f to force.\n");
}
int
main(int argc, char ** argv) {
struct stat statbuf;
struct swap_header_v1_2 *hdr;
int i;
unsigned long long maxpages;
unsigned long long goodpages;
unsigned long long sz;
off_t offset;
int force = 0;
int version = 1;
char *block_count = 0;
char *pp;
char *opt_label = NULL;
unsigned char *uuid = NULL;
#ifdef HAVE_LIBUUID
const char *opt_uuid = NULL;
uuid_t uuid_dat;
#endif
program_name = (argc && *argv) ? argv[0] : "mkswap";
if ((pp = strrchr(program_name, '/')) != NULL)
program_name = pp+1;
setlocale(LC_ALL, "");
bindtextdomain(PACKAGE, LOCALEDIR);
textdomain(PACKAGE);
if (argc == 2 &&
(!strcmp(argv[1], "-V") || !strcmp(argv[1], "--version"))) {
printf(_("%s (%s)\n"), program_name, PACKAGE_STRING);
exit(0);
}
for (i=1; i<argc; i++) {
if (argv[i][0] == '-') {
switch (argv[i][1]) {
case 'c':
check=1;
break;
case 'f':
force=1;
break;
case 'p':
pp = argv[i]+2;
if (!*pp && i+1 < argc)
pp = argv[++i];
if (isnzdigit(*pp))
user_pagesize = atoi(pp);
else
usage();
break;
case 'L':
pp = argv[i]+2;
if (!*pp && i+1 < argc)
pp = argv[++i];
opt_label = pp;
break;
case 'v':
version = atoi(argv[i]+2);
break;
case 'U':
#ifdef HAVE_LIBUUID
opt_uuid = argv[i]+2;
if (!*opt_uuid && i+1 < argc)
opt_uuid = argv[++i];
#else
fprintf(stderr, _("%1$s: warning: ignore -U (UUIDs are unsupported by %1$s)\n"),
program_name);
#endif
break;
default:
usage();
}
} else if (!device_name) {
device_name = argv[i];
} else if (!block_count) {
block_count = argv[i];
} else
usage();
}
if (version != 1) {
fprintf(stderr, _("%s: does not support swapspace version %d.\n"),
program_name, version);
exit(EXIT_FAILURE);
}
#ifdef HAVE_LIBUUID
if(opt_uuid) {
if (uuid_parse(opt_uuid, uuid_dat) != 0)
die(_("error: UUID parsing failed"));
} else
uuid_generate(uuid_dat);
uuid = uuid_dat;
#endif
init_signature_page(); /* get pagesize */
if (!device_name) {
fprintf(stderr,
_("%s: error: Nowhere to set up swap on?\n"),
program_name);
usage();
}
if (block_count) {
/* this silly user specified the number of blocks explicitly */
char *tmp = NULL;
long long blks;
errno = 0;
blks = strtoll(block_count, &tmp, 0);
if ((tmp == block_count) ||
(tmp && *tmp) ||
(errno != 0 && (blks == LLONG_MAX || blks == LLONG_MIN)) ||
blks < 0)
usage();
PAGES = blks / (pagesize / 1024);
}
sz = get_size(device_name);
if (!PAGES) {
PAGES = sz;
} else if (PAGES > sz && !force) {
fprintf(stderr,
_("%s: error: "
"size %llu KiB is larger than device size %llu KiB\n"),
program_name,
PAGES*(pagesize/1024), sz*(pagesize/1024));
exit(1);
}
if (PAGES < MIN_GOODPAGES) {
fprintf(stderr,
_("%s: error: swap area needs to be at least %ld KiB\n"),
program_name, (long)(MIN_GOODPAGES * pagesize/1024));
usage();
}
#ifdef __linux__
if (get_linux_version() >= KERNEL_VERSION(2,3,4))
maxpages = UINT_MAX + 1ULL;
else if (get_linux_version() >= KERNEL_VERSION(2,2,1))
maxpages = V1_MAX_PAGES;
else
#endif
maxpages = V1_OLD_MAX_PAGES;
if (PAGES > maxpages) {
PAGES = maxpages;
fprintf(stderr,
_("%s: warning: truncating swap area to %llu KiB\n"),
program_name, PAGES * pagesize / 1024);
}
if (stat(device_name, &statbuf) < 0) {
perror(device_name);
exit(EXIT_FAILURE);
}
if (S_ISBLK(statbuf.st_mode))
DEV = open(device_name, O_RDWR | O_EXCL);
else
DEV = open(device_name, O_RDWR);
if (DEV < 0) {
perror(device_name);
exit(1);
}
/* Want a block device. Probably not /dev/hda or /dev/hdb. */
if (!S_ISBLK(statbuf.st_mode))
check=0;
else if (statbuf.st_rdev == 0x0300 || statbuf.st_rdev == 0x0340) {
fprintf(stderr,
_("%s: error: "
"will not try to make swapdevice on '%s'\n"),
program_name, device_name);
exit(1);
} else if (check_mount()) {
fprintf(stderr,
_("%s: error: "
"%s is mounted; will not make swapspace.\n"),
program_name, device_name);
exit(1);
}
if (check)
check_blocks();
zap_bootbits(DEV, device_name, force, S_ISBLK(statbuf.st_mode));
hdr = (struct swap_header_v1_2 *) signature_page;
hdr->version = 1;
hdr->last_page = PAGES - 1;
hdr->nr_badpages = badpages;
if (badpages > PAGES - MIN_GOODPAGES)
die(_("Unable to set up swap-space: unreadable"));
goodpages = PAGES - badpages - 1;
printf(_("Setting up swapspace version 1, size = %llu KiB\n"),
goodpages * pagesize / 1024);
write_signature("SWAPSPACE2");
write_uuid_and_label(uuid, opt_label);
offset = 1024;
if (lseek(DEV, offset, SEEK_SET) != offset)
die(_("unable to rewind swap-device"));
if (write_all(DEV, (char *) signature_page + offset,
pagesize - offset) == -1) {
fprintf(stderr, _("%s: %s: unable to write signature page: %s"),
program_name, device_name, strerror(errno));
exit(1);
}
/*
* A subsequent swapon() will fail if the signature
* is not actually on disk. (This is a kernel bug.)
*/
#ifdef HAVE_FSYNC
if (fsync(DEV))
die(_("fsync failed"));
#endif
#ifdef HAVE_LIBSELINUX
if (S_ISREG(statbuf.st_mode) && is_selinux_enabled() > 0) {
security_context_t context_string;
security_context_t oldcontext;
context_t newcontext;
if (fgetfilecon(DEV, &oldcontext) < 0) {
if (errno != ENODATA) {
fprintf(stderr, _("%s: %s: unable to obtain selinux file label: %s\n"),
program_name, device_name,
strerror(errno));
exit(1);
}
if (matchpathcon(device_name, statbuf.st_mode, &oldcontext))
die(_("unable to matchpathcon()"));
}
if (!(newcontext = context_new(oldcontext)))
die(_("unable to create new selinux context"));
if (context_type_set(newcontext, SELINUX_SWAPFILE_TYPE))
die(_("couldn't compute selinux context"));
context_string = context_str(newcontext);
if (strcmp(context_string, oldcontext)!=0) {
if (fsetfilecon(DEV, context_string)) {
fprintf(stderr, _("%s: unable to relabel %s to %s: %s\n"),
program_name, device_name,
context_string,
strerror(errno));
exit(1);
}
}
context_free(newcontext);
freecon(oldcontext);
}
#endif
return 0;
}
