mkswap: default to V1 in any case

[thirdparty/util-linux.git] / disk-utils / mkswap.c

/*
 * 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 <mntent.h>
#include <sys/ioctl.h>          /* for _IO */
#include <sys/utsname.h>
#include <sys/stat.h>
#include <errno.h>
#ifdef HAVE_LIBSELINUX
#include <selinux/selinux.h>
#include <selinux/context.h>
#endif

#include "swapheader.h"
#include "xstrncpy.h"
#include "nls.h"

#ifdef HAVE_LIBUUID
#include <uuid/uuid.h>
#endif

#ifndef _IO
/* pre-1.3.45 */
#define BLKGETSIZE 0x1260
#else
/* same on i386, m68k, arm; different on alpha, mips, sparc, ppc */
#define BLKGETSIZE _IO(0x12,96)
#endif

static char * program_name = "mkswap";
static char * device_name = NULL;
static int DEV = -1;
static unsigned long PAGES = 0;
static unsigned long badpages = 0;
static int check = 0;
static int version = -1;

#define MAKE_VERSION(p,q,r)     (65536*(p) + 256*(q) + (r))

#define SELINUX_SWAPFILE_TYPE   "swapfile_t"

static int
linux_version_code(void) {
        struct utsname my_utsname;
        int p, q, r;

        if (uname(&my_utsname) == 0) {
                p = atoi(strtok(my_utsname.release, "."));
                q = atoi(strtok(NULL, "."));
                r = atoi(strtok(NULL, "."));
                return MAKE_VERSION(p,q,r);
        }
        return 0;
}

#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.
 *
 * Update 05-Feb-2007 (kzak):
 *      - use sysconf(_SC_PAGESIZE) to be consistent with the rest of
 *        util-linux code.  It is the standardized and preferred way of
 *        querying page size.
 */
static int user_pagesize;
static int pagesize;
static unsigned long *signature_page;
struct swap_header_v1 *p;

static void
init_signature_page(void) {

        int kernel_pagesize = pagesize = (int) sysconf(_SC_PAGESIZE);

        if (user_pagesize) {
                if ((user_pagesize & (user_pagesize-1)) ||
                    user_pagesize < 1024) {
                        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 *) malloc(pagesize);
        memset(signature_page, 0, pagesize);
        p = (struct swap_header_v1 *) signature_page;
}

static void
write_signature(char *sig) {
        char *sp = (char *) signature_page;

        strncpy(sp+pagesize-10, sig, 10);
}

#if 0
static int
tohex(int a) {
        return ((a < 10) ? '0'+a : 'a'+a-10);
}

static void
uuid_unparse(unsigned char *uuid, char *s) {
        int i;

        for (i=0; i<16; i++) {
                if (i == 4 || i == 6 || i == 8 || i == 10)
                        *s++ = '-';
                *s++ = tohex((uuid[i] >> 4) & 0xf);
                *s++ = tohex(uuid[i] & 0xf);
        }
        *s = 0;
}
#endif

static void
write_uuid_and_label(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.
 */
#define V0_MAX_PAGES    (8 * (pagesize - 10))
/* 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))

/*
 * One more point of lossage - Linux swapspace really is a mess.
 * The definition of the bitmap used is architecture dependent,
 * and requires one to know whether the machine is bigendian,
 * and if so, whether it will use 32-bit or 64-bit units in
 * test_bit().
 * davem writes: "... is based upon an unsigned long type of
 * the cpu and the native endianness".
 * So, it seems we can write `unsigned long' below.
 * However, sparc64 uses 64-bit units in the kernel, while
 * mkswap may have been translated with 32-bit longs. Thus,
 * we need an explicit test for version 0 swap on sparc64.
 */

static void
bit_set (unsigned long *addr, unsigned int nr) {
        unsigned int r, m;

        if(is_be64()) {
                unsigned long long *bitmap = (unsigned long long *) addr;
                unsigned long long bitnum = (unsigned long long) nr;
                unsigned long long rl, ml;

                bitmap += bitnum / (8 * sizeof(long long));
                rl = *bitmap;
                ml = 1ULL << (bitnum & (8ULL * sizeof(long long) - 1ULL));
                *bitmap = rl | ml;
                return;
        }

        addr += nr / (8 * sizeof(unsigned long));
        r = *addr;
        m = 1 << (nr & (8 * sizeof(unsigned long) - 1));
        *addr = r | m;
}

static int
bit_test_and_clear (unsigned long *addr, unsigned int nr) {
        unsigned int r, m;

        if(is_be64()) {
                unsigned long long *bitmap = (unsigned long long *) addr;
                unsigned long long bitnum = (unsigned long long) nr;
                unsigned long long rl, ml;

                bitmap += bitnum / (8 * sizeof(long long));
                rl = *bitmap;
                ml = 1ULL << (bitnum & (8ULL * sizeof(long long) - 1ULL));
                *bitmap = rl & ~ml;
                return ((rl & ml) != 0ULL);
        }

        addr += nr / (8 * sizeof(unsigned long));
        r = *addr;
        m = 1 << (nr & (8 * sizeof(unsigned long) - 1));
        *addr = r & ~m;
        return (r & m) != 0;
}

static void
usage(void) {
        fprintf(stderr,
                _("Usage: %s [-c] [-v0|-v1] [-pPAGESZ] [-L label] /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_ok(int page) {
        if (version==0)
                bit_set(signature_page, page);
}

static void
page_bad(int page) {
        if (version == 0)
                bit_test_and_clear(signature_page, page);
        else {
                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 (!check) {
                        page_ok(current_page++);
                        continue;
                }
                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++);
                        continue;
                }
                page_ok(current_page++);
        }
        if (badpages == 1)
                printf(_("one bad page\n"));
        else if (badpages > 1)
                printf(_("%lu bad pages\n"), badpages);
}

static long
valid_offset (int fd, off_t offset) {
        char ch;

        if (lseek (fd, offset, 0) < 0)
                return 0;
        if (read (fd, &ch, 1) < 1)
                return 0;
        return 1;
}

static off_t
find_size (int fd) {
        off_t high, low;

        low = 0;
        for (high = 1; high > 0 && valid_offset (fd, high); high *= 2)
                low = high;
        while (low < high - 1) {
                const off_t mid = (low + high) / 2;

                if (valid_offset (fd, mid))
                        low = mid;
                else
                        high = mid;
        }
        return (low + 1);
}

/* return size in pages, to avoid integer overflow */
static unsigned long
get_size(const char  *file) {
        int     fd;
        unsigned long   size;

        fd = open(file, O_RDONLY);
        if (fd < 0) {
                perror(file);
                exit(1);
        }
        if (ioctl(fd, BLKGETSIZE, &size) >= 0) {
                int sectors_per_page = pagesize/512;
                size /= sectors_per_page;
        } else {
                size = find_size(fd) / 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 (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;
}

int
main(int argc, char ** argv) {
        struct stat statbuf;
        int i;
        unsigned long maxpages;
        unsigned long goodpages;
        unsigned long sz;
        off_t offset;
        int force = 0;
        char *block_count = 0;
        char *pp;
        char *opt_label = NULL;
        char *uuid = NULL;
#ifdef HAVE_LIBUUID
        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;
                                default:
                                        usage();
                        }
                } else if (!device_name) {
                        device_name = argv[i];
                } else if (!block_count) {
                        block_count = argv[i];
                } else
                        usage();
        }

#ifdef HAVE_LIBUUID
        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;
                int blocks_per_page = pagesize/1024;
                PAGES = strtoul(block_count,&tmp,0)/blocks_per_page;
                if (*tmp)
                        usage();
        }
        sz = get_size(device_name);
        if (!PAGES) {
                PAGES = sz;
        } else if (PAGES > sz && !force) {
                fprintf(stderr,
                        _("%s: error: "
                          "size %lu is larger than device size %lu\n"),
                        program_name,
                        PAGES*(pagesize/1024), sz*(pagesize/1024));
                exit(1);
        }

        if (version == -1) {
                /* labels only for v1 */
                if (opt_label)
                        version = 1;
                else
                /* use version 1 as default, if possible */
                if (linux_version_code() < MAKE_VERSION(2,1,117))
                        version = 0;
                else if (pagesize < 2048)
                        version = 0;
                else
                        version = 1;
        }
        if (version != 0 && version != 1) {
                fprintf(stderr, _("%s: error: unknown version %d\n"),
                        program_name, version);
                usage();
        }

        if (PAGES < 10) {
                fprintf(stderr,
                        _("%s: error: swap area needs to be at least %ldkB\n"),
                        program_name, (long)(10 * pagesize / 1000));
                usage();
        }

        if (version == 0)
                maxpages = V0_MAX_PAGES;
        else if (linux_version_code() >= MAKE_VERSION(2,3,4))
                maxpages = PAGES;
        else if (linux_version_code() >= MAKE_VERSION(2,2,1))
                maxpages = V1_MAX_PAGES;
        else
                maxpages = V1_OLD_MAX_PAGES;

        if (PAGES > maxpages) {
                PAGES = maxpages;
                fprintf(stderr,
                        _("%s: warning: truncating swap area to %ldkB\n"),
                        program_name, PAGES * pagesize / 1000);
        }

        if (opt_label && version == 0) {
                fprintf(stderr,
                        _("%s: error: label only with v1 swap area\n"),
                        program_name);
                usage();
        }

        DEV = open(device_name,O_RDWR);
        if (DEV < 0 || fstat(DEV, &statbuf) < 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);
        }

#ifdef __sparc__
        if (!force && version == 0) {
                /* Don't overwrite partition table unless forced */
                unsigned char *buffer = (unsigned char *)signature_page;
                unsigned short *q, sum;

                if (read(DEV, buffer, 512) != 512)
                        die(_("fatal: first page unreadable"));
                if (buffer[508] == 0xDA && buffer[509] == 0xBE) {
                        q = (unsigned short *)(buffer + 510);
                        for (sum = 0; q >= (unsigned short *) buffer;)
                                sum ^= *q--;
                        if (!sum) {
                                fprintf(stderr, _("\
%s: Device '%s' contains a valid Sun disklabel.\n\
This probably means creating v0 swap would destroy your partition table\n\
No swap created. If you really want to create swap v0 on that device, use\n\
the -f option to force it.\n"),
                                        program_name, device_name);
                                exit(1);
                        }
                }
        }
#endif

        if (version == 0 || check)
                check_blocks();
        if (version == 0 && !bit_test_and_clear(signature_page,0))
                die(_("fatal: first page unreadable"));
        if (version == 1) {
                p->version = version;
                p->last_page = PAGES-1;
                p->nr_badpages = badpages;
        }

        goodpages = PAGES - badpages - 1;
        if ((long) goodpages <= 0)
                die(_("Unable to set up swap-space: unreadable"));
        printf(_("Setting up swapspace version %d, size = %llu kB\n"),
                version, (unsigned long long)goodpages * pagesize / 1000);
        write_signature((version == 0) ? "SWAP-SPACE" : "SWAPSPACE2");

        if (version == 1)
                write_uuid_and_label(uuid, opt_label);

        offset = ((version == 0) ? 0 : 1024);
        if (lseek(DEV, offset, SEEK_SET) != offset)
                die(_("unable to rewind swap-device"));
        if (write(DEV,(char*)signature_page+offset, pagesize-offset)
            != pagesize-offset)
                die(_("unable to write signature page"));

        /*
         * 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()) {
                security_context_t context_string;
                security_context_t oldcontext;
                context_t newcontext;

                if ((fgetfilecon(DEV, &oldcontext) < 0) &&
                    (errno != ENODATA)) {
                        fprintf(stderr, _("%s: %s: unable to obtain selinux file label: %s\n"),
                                        program_name, device_name,
                                        strerror(errno));
                        exit(1);
                }
                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;
}