disk-utils/mkswap.c

   1 /*
   2  * mkswap.c - set up a linux swap device
   3  *
   4  * Copyright (C) 1991 Linus Torvalds
   5  *               20.12.91 - time began. Got VM working yesterday by doing this by hand.
   6  *
   7  * Copyright (C) 1999 Jakub Jelinek <jj@ultra.linux.cz>
   8  * Copyright (C) 2007-2014 Karel Zak <kzak@redhat.com>
   9  */
  10
  11 #include <stdio.h>
  12 #include <unistd.h>
  13 #include <string.h>
  14 #include <fcntl.h>
  15 #include <stdlib.h>
  16 #include <limits.h>
  17 #include <sys/utsname.h>
  18 #include <sys/stat.h>
  19 #include <errno.h>
  20 #include <getopt.h>
  21 #include <assert.h>
  22 #ifdef HAVE_LIBSELINUX
  23 #include <selinux/selinux.h>
  24 #include <selinux/context.h>
  25 #endif
  26
  27 #include "linux_version.h"
  28 #include "swapheader.h"
  29 #include "strutils.h"
  30 #include "nls.h"
  31 #include "blkdev.h"
  32 #include "pathnames.h"
  33 #include "all-io.h"
  34 #include "xalloc.h"
  35 #include "c.h"
  36 #include "closestream.h"
  37 #include "ismounted.h"
  38
  39 #ifdef HAVE_LIBUUID
  40 # include <uuid.h>
  41 #endif
  42
  43 #ifdef HAVE_LIBBLKID
  44 # include <blkid.h>
  45 #endif
  46
  47 #define MIN_GOODPAGES   10
  48
  49 #define SELINUX_SWAPFILE_TYPE   "swapfile_t"
  50
  51 struct mkswap_control {
  52         struct swap_header_v1_2 *hdr;           /* swap header */
  53         void                    *signature_page;/* buffer with swap header */
  54
  55         char                    *devname;       /* device or file name */
  56         struct stat             devstat;        /* stat() result */
  57         int                     fd;             /* swap file descriptor */
  58
  59         unsigned long long      npages;         /* number of pages */
  60         unsigned long           nbadpages;      /* number of bad pages */
  61
  62         int                     user_pagesize;  /* --pagesize */
  63         int                     pagesize;       /* final pagesize used for the header */
  64
  65         char                    *opt_label;     /* LABEL as specified on command line */
  66         unsigned char           *uuid;          /* UUID parsed by libbuuid */
  67
  68         unsigned int            check:1,        /* --check */
  69                                 force:1;        /* --force */
  70 };
  71
  72 static void init_signature_page(struct mkswap_control *ctl)
  73 {
  74         const int kernel_pagesize = getpagesize();
  75
  76         if (ctl->user_pagesize) {
  77                 if (ctl->user_pagesize < 0 || !is_power_of_2(ctl->user_pagesize) ||
  78                     (size_t) ctl->user_pagesize < sizeof(struct swap_header_v1_2) + 10)
  79                         errx(EXIT_FAILURE,
  80                              _("Bad user-specified page size %u"),
  81                                ctl->user_pagesize);
  82                 if (ctl->user_pagesize != kernel_pagesize)
  83                         warnx(_("Using user-specified page size %d, "
  84                                 "instead of the system value %d"),
  85                                 ctl->user_pagesize, kernel_pagesize);
  86                 ctl->pagesize = ctl->user_pagesize;
  87         } else
  88                 ctl->pagesize = kernel_pagesize;
  89
  90         ctl->signature_page = xcalloc(1, ctl->pagesize);
  91         ctl->hdr = (struct swap_header_v1_2 *) ctl->signature_page;
  92 }
  93
  94 static void deinit_signature_page(struct mkswap_control *ctl)
  95 {
  96         free(ctl->signature_page);
  97
  98         ctl->hdr = NULL;
  99         ctl->signature_page = NULL;
 100 }
 101
 102 static void set_signature(const struct mkswap_control *ctl)
 103 {
 104         char *sp = (char *) ctl->signature_page;
 105
 106         assert(sp);
 107         memcpy(sp + ctl->pagesize - SWAP_SIGNATURE_SZ, SWAP_SIGNATURE, SWAP_SIGNATURE_SZ);
 108 }
 109
 110 static void set_uuid_and_label(const struct mkswap_control *ctl)
 111 {
 112         assert(ctl);
 113         assert(ctl->hdr);
 114
 115         /* set UUID */
 116         if (ctl->uuid)
 117                 memcpy(ctl->hdr->uuid, ctl->uuid, sizeof(ctl->hdr->uuid));
 118
 119         /* set LABEL */
 120         if (ctl->opt_label) {
 121                 xstrncpy(ctl->hdr->volume_name,
 122                          ctl->opt_label, sizeof(ctl->hdr->volume_name));
 123                 if (strlen(ctl->opt_label) > strlen(ctl->hdr->volume_name))
 124                         warnx(_("Label was truncated."));
 125         }
 126
 127         /* report results */
 128         if (ctl->uuid || ctl->opt_label) {
 129                 if (ctl->opt_label)
 130                         printf("LABEL=%s, ", ctl->hdr->volume_name);
 131                 else
 132                         printf(_("no label, "));
 133 #ifdef HAVE_LIBUUID
 134                 if (ctl->uuid) {
 135                         char uuid_string[UUID_STR_LEN];
 136                         uuid_unparse(ctl->uuid, uuid_string);
 137                         printf("UUID=%s\n", uuid_string);
 138                 } else
 139 #endif
 140                         printf(_("no uuid\n"));
 141         }
 142 }
 143
 144 static void __attribute__((__noreturn__)) usage(void)
 145 {
 146         FILE *out = stdout;
 147         fprintf(out,
 148                 _("\nUsage:\n"
 149                   " %s [options] device [size]\n"),
 150                 program_invocation_short_name);
 151
 152         fputs(USAGE_SEPARATOR, out);
 153         fputs(_("Set up a Linux swap area.\n"), out);
 154
 155         fprintf(out, _(
 156                 "\nOptions:\n"
 157                 " -c, --check               check bad blocks before creating the swap area\n"
 158                 " -f, --force               allow swap size area be larger than device\n"
 159                 " -p, --pagesize SIZE       specify page size in bytes\n"
 160                 " -L, --label LABEL         specify label\n"
 161                 " -v, --swapversion NUM     specify swap-space version number\n"
 162                 " -U, --uuid UUID           specify the uuid to use\n"
 163                 ));
 164         printf(USAGE_HELP_OPTIONS(27));
 165
 166         printf(USAGE_MAN_TAIL("mkswap(8)"));
 167         exit(EXIT_SUCCESS);
 168 }
 169
 170 static void page_bad(struct mkswap_control *ctl, unsigned int page)
 171 {
 172         const unsigned long max_badpages =
 173                 (ctl->pagesize - 1024 - 128 * sizeof(int) - 10) / sizeof(int);
 174
 175         if (ctl->nbadpages == max_badpages)
 176                 errx(EXIT_FAILURE, _("too many bad pages: %lu"), max_badpages);
 177
 178         ctl->hdr->badpages[ctl->nbadpages] = page;
 179         ctl->nbadpages++;
 180 }
 181
 182 static void check_blocks(struct mkswap_control *ctl)
 183 {
 184         unsigned int current_page = 0;
 185         int do_seek = 1;
 186         char *buffer;
 187
 188         assert(ctl);
 189         assert(ctl->fd > -1);
 190
 191         buffer = xmalloc(ctl->pagesize);
 192         while (current_page < ctl->npages) {
 193                 ssize_t rc;
 194                 off_t offset = (off_t) current_page * ctl->pagesize;
 195
 196                 if (do_seek && lseek(ctl->fd, offset, SEEK_SET) != offset)
 197                         errx(EXIT_FAILURE, _("seek failed in check_blocks"));
 198
 199                 rc = read(ctl->fd, buffer, ctl->pagesize);
 200                 do_seek = (rc < 0 || rc != ctl->pagesize);
 201                 if (do_seek)
 202                         page_bad(ctl, current_page);
 203                 current_page++;
 204         }
 205         printf(P_("%lu bad page\n", "%lu bad pages\n", ctl->nbadpages), ctl->nbadpages);
 206         free(buffer);
 207 }
 208
 209 /* return size in pages */
 210 static unsigned long long get_size(const struct mkswap_control *ctl)
 211 {
 212         int fd;
 213         unsigned long long size;
 214
 215         fd = open(ctl->devname, O_RDONLY);
 216         if (fd < 0)
 217                 err(EXIT_FAILURE, _("cannot open %s"), ctl->devname);
 218         if (blkdev_get_size(fd, &size) == 0)
 219                 size /= ctl->pagesize;
 220
 221         close(fd);
 222         return size;
 223 }
 224
 225 #ifdef HAVE_LIBBLKID
 226 static blkid_probe new_prober(const struct mkswap_control *ctl)
 227 {
 228         blkid_probe pr = blkid_new_probe();
 229         if (!pr)
 230                 errx(EXIT_FAILURE, _("unable to alloc new libblkid probe"));
 231         if (blkid_probe_set_device(pr, ctl->fd, 0, 0))
 232                 errx(EXIT_FAILURE, _("unable to assign device to libblkid probe"));
 233         return pr;
 234 }
 235 #endif
 236
 237 static void open_device(struct mkswap_control *ctl)
 238 {
 239         assert(ctl);
 240         assert(ctl->devname);
 241
 242         if (stat(ctl->devname, &ctl->devstat) < 0)
 243                 err(EXIT_FAILURE, _("stat of %s failed"), ctl->devname);
 244         ctl->fd = open_blkdev_or_file(&ctl->devstat, ctl->devname, O_RDWR);
 245         if (ctl->fd < 0)
 246                 err(EXIT_FAILURE, _("cannot open %s"), ctl->devname);
 247         if (ctl->check && S_ISREG(ctl->devstat.st_mode)) {
 248                 ctl->check = 0;
 249                 warnx(_("warning: checking bad blocks from swap file is not supported: %s"),
 250                        ctl->devname);
 251         }
 252 }
 253
 254 static void wipe_device(struct mkswap_control *ctl)
 255 {
 256         char *type = NULL;
 257         int zap = 1;
 258 #ifdef HAVE_LIBBLKID
 259         blkid_probe pr = NULL;
 260 #endif
 261         if (!ctl->force) {
 262                 const char *v = NULL;
 263
 264                 if (lseek(ctl->fd, 0, SEEK_SET) != 0)
 265                         errx(EXIT_FAILURE, _("unable to rewind swap-device"));
 266
 267 #ifdef HAVE_LIBBLKID
 268                 pr = new_prober(ctl);
 269                 blkid_probe_enable_partitions(pr, 1);
 270                 blkid_probe_enable_superblocks(pr, 0);
 271
 272                 if (blkid_do_fullprobe(pr) == 0 &&
 273                     blkid_probe_lookup_value(pr, "PTTYPE", &v, NULL) == 0 && v) {
 274                         type = xstrdup(v);
 275                         zap = 0;
 276                 }
 277 #else
 278                 /* don't zap if compiled without libblkid */
 279                 zap = 0;
 280 #endif
 281         }
 282
 283         if (zap) {
 284                 /*
 285                  * Wipe bootbits
 286                  */
 287                 char buf[1024] = { '\0' };
 288
 289                 if (lseek(ctl->fd, 0, SEEK_SET) != 0)
 290                         errx(EXIT_FAILURE, _("unable to rewind swap-device"));
 291
 292                 if (write_all(ctl->fd, buf, sizeof(buf)))
 293                         errx(EXIT_FAILURE, _("unable to erase bootbits sectors"));
 294 #ifdef HAVE_LIBBLKID
 295                 /*
 296                  * Wipe rest of the device
 297                  */
 298                 if (!pr)
 299                         pr = new_prober(ctl);
 300
 301                 blkid_probe_enable_superblocks(pr, 1);
 302                 blkid_probe_enable_partitions(pr, 0);
 303                 blkid_probe_set_superblocks_flags(pr, BLKID_SUBLKS_MAGIC|BLKID_SUBLKS_TYPE);
 304
 305                 while (blkid_do_probe(pr) == 0) {
 306                         const char *data = NULL;
 307
 308                         if (blkid_probe_lookup_value(pr, "TYPE", &data, NULL) == 0 && data)
 309                                 warnx(_("%s: warning: wiping old %s signature."), ctl->devname, data);
 310                         blkid_do_wipe(pr, 0);
 311                 }
 312 #endif
 313         } else {
 314                 warnx(_("%s: warning: don't erase bootbits sectors"),
 315                         ctl->devname);
 316                 if (type)
 317                         fprintf(stderr, _("        (%s partition table detected). "), type);
 318                 else
 319                         fprintf(stderr, _("        (compiled without libblkid). "));
 320                 fprintf(stderr, _("Use -f to force.\n"));
 321         }
 322         free(type);
 323 #ifdef HAVE_LIBBLKID
 324         blkid_free_probe(pr);
 325 #endif
 326 }
 327
 328 #define SIGNATURE_OFFSET        1024
 329
 330 static void write_header_to_device(struct mkswap_control *ctl)
 331 {
 332         assert(ctl);
 333         assert(ctl->fd > -1);
 334         assert(ctl->signature_page);
 335
 336         if (lseek(ctl->fd, SIGNATURE_OFFSET, SEEK_SET) != SIGNATURE_OFFSET)
 337                 errx(EXIT_FAILURE, _("unable to rewind swap-device"));
 338
 339         if (write_all(ctl->fd, (char *) ctl->signature_page + SIGNATURE_OFFSET,
 340                       ctl->pagesize - SIGNATURE_OFFSET) == -1)
 341                 err(EXIT_FAILURE,
 342                         _("%s: unable to write signature page"),
 343                         ctl->devname);
 344 }
 345
 346 int main(int argc, char **argv)
 347 {
 348         struct mkswap_control ctl = { .fd = -1 };
 349         int c, permMask;
 350         uint64_t sz;
 351         int version = SWAP_VERSION;
 352         char *block_count = NULL, *strsz = NULL;
 353 #ifdef HAVE_LIBUUID
 354         const char *opt_uuid = NULL;
 355         uuid_t uuid_dat;
 356 #endif
 357         static const struct option longopts[] = {
 358                 { "check",       no_argument,       NULL, 'c' },
 359                 { "force",       no_argument,       NULL, 'f' },
 360                 { "pagesize",    required_argument, NULL, 'p' },
 361                 { "label",       required_argument, NULL, 'L' },
 362                 { "swapversion", required_argument, NULL, 'v' },
 363                 { "uuid",        required_argument, NULL, 'U' },
 364                 { "version",     no_argument,       NULL, 'V' },
 365                 { "help",        no_argument,       NULL, 'h' },
 366                 { NULL,          0, NULL, 0 }
 367         };
 368
 369         setlocale(LC_ALL, "");
 370         bindtextdomain(PACKAGE, LOCALEDIR);
 371         textdomain(PACKAGE);
 372         close_stdout_atexit();
 373
 374         while((c = getopt_long(argc, argv, "cfp:L:v:U:Vh", longopts, NULL)) != -1) {
 375                 switch (c) {
 376                 case 'c':
 377                         ctl.check = 1;
 378                         break;
 379                 case 'f':
 380                         ctl.force = 1;
 381                         break;
 382                 case 'p':
 383                         ctl.user_pagesize = strtou32_or_err(optarg, _("parsing page size failed"));
 384                         break;
 385                 case 'L':
 386                         ctl.opt_label = optarg;
 387                         break;
 388                 case 'v':
 389                         version = strtos32_or_err(optarg, _("parsing version number failed"));
 390                         if (version != SWAP_VERSION)
 391                                 errx(EXIT_FAILURE,
 392                                         _("swapspace version %d is not supported"), version);
 393                         break;
 394                 case 'U':
 395 #ifdef HAVE_LIBUUID
 396                         opt_uuid = optarg;
 397 #else
 398                         warnx(_("warning: ignoring -U (UUIDs are unsupported by %s)"),
 399                                 program_invocation_short_name);
 400 #endif
 401                         break;
 402                 case 'V':
 403                         print_version(EXIT_SUCCESS);
 404                 case 'h':
 405                         usage();
 406                 default:
 407                         errtryhelp(EXIT_FAILURE);
 408                 }
 409         }
 410
 411         if (optind < argc)
 412                 ctl.devname = argv[optind++];
 413         if (optind < argc)
 414                 block_count = argv[optind++];
 415         if (optind != argc) {
 416                 warnx(_("only one device argument is currently supported"));
 417                 errtryhelp(EXIT_FAILURE);
 418         }
 419
 420 #ifdef HAVE_LIBUUID
 421         if(opt_uuid) {
 422                 if (uuid_parse(opt_uuid, uuid_dat) != 0)
 423                         errx(EXIT_FAILURE, _("error: parsing UUID failed"));
 424         } else
 425                 uuid_generate(uuid_dat);
 426         ctl.uuid = uuid_dat;
 427 #endif
 428
 429         init_signature_page(&ctl);      /* get pagesize and allocate signature page */
 430
 431         if (!ctl.devname) {
 432                 warnx(_("error: Nowhere to set up swap on?"));
 433                 errtryhelp(EXIT_FAILURE);
 434         }
 435         if (block_count) {
 436                 /* this silly user specified the number of blocks explicitly */
 437                 uint64_t blks = strtou64_or_err(block_count,
 438                                         _("invalid block count argument"));
 439                 ctl.npages = blks / (ctl.pagesize / 1024);
 440         }
 441
 442         sz = get_size(&ctl);
 443         if (!ctl.npages)
 444                 ctl.npages = sz;
 445         else if (ctl.npages > sz && !ctl.force)
 446                 errx(EXIT_FAILURE,
 447                         _("error: "
 448                           "size %llu KiB is larger than device size %"PRIu64" KiB"),
 449                         ctl.npages * (ctl.pagesize / 1024), sz * (ctl.pagesize / 1024));
 450
 451         if (ctl.npages < MIN_GOODPAGES)
 452                 errx(EXIT_FAILURE,
 453                      _("error: swap area needs to be at least %ld KiB"),
 454                      (long)(MIN_GOODPAGES * ctl.pagesize / 1024));
 455         if (ctl.npages > UINT32_MAX) {
 456                 /* true when swap is bigger than 17.59 terabytes */
 457                 ctl.npages = UINT32_MAX;
 458                 warnx(_("warning: truncating swap area to %llu KiB"),
 459                         ctl.npages * ctl.pagesize / 1024);
 460         }
 461
 462         if (is_mounted(ctl.devname))
 463                 errx(EXIT_FAILURE, _("error: "
 464                         "%s is mounted; will not make swapspace"),
 465                         ctl.devname);
 466
 467         open_device(&ctl);
 468         permMask = S_ISBLK(ctl.devstat.st_mode) ? 07007 : 07077;
 469         if ((ctl.devstat.st_mode & permMask) != 0)
 470                 warnx(_("%s: insecure permissions %04o, %04o suggested."),
 471                         ctl.devname, ctl.devstat.st_mode & 07777,
 472                         ~permMask & 0666);
 473         if (getuid() == 0 && S_ISREG(ctl.devstat.st_mode) && ctl.devstat.st_uid != 0)
 474                 warnx(_("%s: insecure file owner %d, 0 (root) suggested."),
 475                         ctl.devname, ctl.devstat.st_uid);
 476
 477
 478         if (ctl.check)
 479                 check_blocks(&ctl);
 480
 481         wipe_device(&ctl);
 482
 483         assert(ctl.hdr);
 484         ctl.hdr->version = version;
 485         ctl.hdr->last_page = ctl.npages - 1;
 486         ctl.hdr->nr_badpages = ctl.nbadpages;
 487
 488         if ((ctl.npages - MIN_GOODPAGES) < ctl.nbadpages)
 489                 errx(EXIT_FAILURE, _("Unable to set up swap-space: unreadable"));
 490
 491         sz = (ctl.npages - ctl.nbadpages - 1) * ctl.pagesize;
 492         strsz = size_to_human_string(SIZE_SUFFIX_SPACE | SIZE_SUFFIX_3LETTER, sz);
 493
 494         printf(_("Setting up swapspace version %d, size = %s (%"PRIu64" bytes)\n"),
 495                 version, strsz, sz);
 496         free(strsz);
 497
 498         set_signature(&ctl);
 499         set_uuid_and_label(&ctl);
 500
 501         write_header_to_device(&ctl);
 502
 503         deinit_signature_page(&ctl);
 504
 505 #ifdef HAVE_LIBSELINUX
 506         if (S_ISREG(ctl.devstat.st_mode) && is_selinux_enabled() > 0) {
 507                 security_context_t context_string;
 508                 security_context_t oldcontext;
 509                 context_t newcontext;
 510
 511                 if (fgetfilecon(ctl.fd, &oldcontext) < 0) {
 512                         if (errno != ENODATA)
 513                                 err(EXIT_FAILURE,
 514                                         _("%s: unable to obtain selinux file label"),
 515                                         ctl.devname);
 516                         if (matchpathcon(ctl.devname, ctl.devstat.st_mode, &oldcontext))
 517                                 errx(EXIT_FAILURE, _("unable to matchpathcon()"));
 518                 }
 519                 if (!(newcontext = context_new(oldcontext)))
 520                         errx(EXIT_FAILURE, _("unable to create new selinux context"));
 521                 if (context_type_set(newcontext, SELINUX_SWAPFILE_TYPE))
 522                         errx(EXIT_FAILURE, _("couldn't compute selinux context"));
 523
 524                 context_string = context_str(newcontext);
 525
 526                 if (strcmp(context_string, oldcontext)!=0) {
 527                         if (fsetfilecon(ctl.fd, context_string) && errno != ENOTSUP)
 528                                 err(EXIT_FAILURE, _("unable to relabel %s to %s"),
 529                                                 ctl.devname, context_string);
 530                 }
 531                 context_free(newcontext);
 532                 freecon(oldcontext);
 533         }
 534 #endif
 535         /*
 536          * A subsequent swapon() will fail if the signature
 537          * is not actually on disk. (This is a kernel bug.)
 538          * The fsync() in close_fd() will take care of writing.
 539          */
 540         if (close_fd(ctl.fd) != 0)
 541                 err(EXIT_FAILURE, _("write failed"));
 542         return EXIT_SUCCESS;
 543 }