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->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[37];
 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(FILE *out)
 145 {
 146         fprintf(out,
 147                 _("\nUsage:\n"
 148                   " %s [options] device [size]\n"),
 149                 program_invocation_short_name);
 150
 151         fputs(USAGE_SEPARATOR, out);
 152         fputs(_("Set up a Linux swap area.\n"), out);
 153
 154         fprintf(out, _(
 155                 "\nOptions:\n"
 156                 " -c, --check               check bad blocks before creating the swap area\n"
 157                 " -f, --force               allow swap size area be larger than device\n"
 158                 " -p, --pagesize SIZE       specify page size in bytes\n"
 159                 " -L, --label LABEL         specify label\n"
 160                 " -v, --swapversion NUM     specify swap-space version number\n"
 161                 " -U, --uuid UUID           specify the uuid to use\n"
 162                 " -V, --version             output version information and exit\n"
 163                 " -h, --help                display this help and exit\n\n"));
 164
 165         exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
 166 }
 167
 168 static void page_bad(struct mkswap_control *ctl, unsigned int page)
 169 {
 170         const unsigned long max_badpages =
 171                 (ctl->pagesize - 1024 - 128 * sizeof(int) - 10) / sizeof(int);
 172
 173         if (ctl->nbadpages == max_badpages)
 174                 errx(EXIT_FAILURE, _("too many bad pages: %lu"), max_badpages);
 175
 176         ctl->hdr->badpages[ctl->nbadpages] = page;
 177         ctl->nbadpages++;
 178 }
 179
 180 static void check_blocks(struct mkswap_control *ctl)
 181 {
 182         unsigned int current_page = 0;
 183         int do_seek = 1;
 184         char *buffer;
 185
 186         assert(ctl);
 187         assert(ctl->fd > -1);
 188
 189         buffer = xmalloc(ctl->pagesize);
 190         while (current_page < ctl->npages) {
 191                 ssize_t rc;
 192
 193                 if (do_seek && lseek(ctl->fd, current_page * ctl->pagesize, SEEK_SET) !=
 194                     current_page * ctl->pagesize)
 195                         errx(EXIT_FAILURE, _("seek failed in check_blocks"));
 196
 197                 rc = read(ctl->fd, buffer, ctl->pagesize);
 198                 do_seek = (rc < 0 || rc != ctl->pagesize);
 199                 if (do_seek)
 200                         page_bad(ctl, current_page);
 201                 current_page++;
 202         }
 203         printf(P_("%lu bad page\n", "%lu bad pages\n", ctl->nbadpages), ctl->nbadpages);
 204         free(buffer);
 205 }
 206
 207 /* return size in pages */
 208 static unsigned long long get_size(const struct mkswap_control *ctl)
 209 {
 210         int fd;
 211         unsigned long long size;
 212
 213         fd = open(ctl->devname, O_RDONLY);
 214         if (fd < 0)
 215                 err(EXIT_FAILURE, _("cannot open %s"), ctl->devname);
 216         if (blkdev_get_size(fd, &size) == 0)
 217                 size /= ctl->pagesize;
 218
 219         close(fd);
 220         return size;
 221 }
 222
 223 #ifdef HAVE_LIBBLKID
 224 static blkid_probe new_prober(const struct mkswap_control *ctl)
 225 {
 226         blkid_probe pr = blkid_new_probe();
 227         if (!pr)
 228                 errx(EXIT_FAILURE, _("unable to alloc new libblkid probe"));
 229         if (blkid_probe_set_device(pr, ctl->fd, 0, 0))
 230                 errx(EXIT_FAILURE, _("unable to assign device to libblkid probe"));
 231         return pr;
 232 }
 233 #endif
 234
 235 static void open_device(struct mkswap_control *ctl)
 236 {
 237         assert(ctl);
 238         assert(ctl->devname);
 239
 240         if (stat(ctl->devname, &ctl->devstat) < 0)
 241                 err(EXIT_FAILURE, _("stat of %s failed"), ctl->devname);
 242         ctl->fd = open_blkdev_or_file(&ctl->devstat, ctl->devname, O_RDWR);
 243         if (ctl->fd < 0)
 244                 err(EXIT_FAILURE, _("cannot open %s"), ctl->devname);
 245         if (ctl->check && S_ISREG(ctl->devstat.st_mode)) {
 246                 ctl->check = 0;
 247                 warnx(_("warning: checking bad blocks from swap file is not supported: %s"),
 248                        ctl->devname);
 249         }
 250 }
 251
 252 static void wipe_device(struct mkswap_control *ctl)
 253 {
 254         char *type = NULL;
 255         int zap = 1;
 256 #ifdef HAVE_LIBBLKID
 257         blkid_probe pr = NULL;
 258 #endif
 259         if (!ctl->force) {
 260                 if (lseek(ctl->fd, 0, SEEK_SET) != 0)
 261                         errx(EXIT_FAILURE, _("unable to rewind swap-device"));
 262
 263 #ifdef HAVE_LIBBLKID
 264                 pr = new_prober(ctl);
 265                 blkid_probe_enable_partitions(pr, 1);
 266                 blkid_probe_enable_superblocks(pr, 0);
 267
 268                 if (blkid_do_fullprobe(pr) == 0 &&
 269                     blkid_probe_lookup_value(pr, "PTTYPE",
 270                                 (const char **) &type, NULL) == 0 && type) {
 271                         type = xstrdup(type);
 272                         zap = 0;
 273                 }
 274 #else
 275                 /* don't zap if compiled without libblkid */
 276                 zap = 0;
 277 #endif
 278         }
 279
 280         if (zap) {
 281                 /*
 282                  * Wipe bootbits
 283                  */
 284                 char buf[1024] = { '\0' };
 285
 286                 if (lseek(ctl->fd, 0, SEEK_SET) != 0)
 287                         errx(EXIT_FAILURE, _("unable to rewind swap-device"));
 288
 289                 if (write_all(ctl->fd, buf, sizeof(buf)))
 290                         errx(EXIT_FAILURE, _("unable to erase bootbits sectors"));
 291 #ifdef HAVE_LIBBLKID
 292                 /*
 293                  * Wipe rest of the device
 294                  */
 295                 if (!pr)
 296                         pr = new_prober(ctl);
 297
 298                 blkid_probe_enable_superblocks(pr, 1);
 299                 blkid_probe_enable_partitions(pr, 0);
 300                 blkid_probe_set_superblocks_flags(pr, BLKID_SUBLKS_MAGIC|BLKID_SUBLKS_TYPE);
 301
 302                 while (blkid_do_probe(pr) == 0) {
 303                         const char *data = NULL;
 304
 305                         if (blkid_probe_lookup_value(pr, "TYPE", &data, NULL) == 0 && data)
 306                                 warnx(_("%s: warning: wiping old %s signature."), ctl->devname, data);
 307                         blkid_do_wipe(pr, 0);
 308                 }
 309 #endif
 310         } else {
 311                 warnx(_("%s: warning: don't erase bootbits sectors"),
 312                         ctl->devname);
 313                 if (type)
 314                         fprintf(stderr, _("        (%s partition table detected). "), type);
 315                 else
 316                         fprintf(stderr, _("        (compiled without libblkid). "));
 317                 fprintf(stderr, _("Use -f to force.\n"));
 318         }
 319         free(type);
 320 #ifdef HAVE_LIBBLKID
 321         blkid_free_probe(pr);
 322 #endif
 323 }
 324
 325 #define SIGNATURE_OFFSET        1024
 326
 327 static void write_header_to_device(struct mkswap_control *ctl)
 328 {
 329         assert(ctl);
 330         assert(ctl->fd > -1);
 331         assert(ctl->signature_page);
 332
 333         if (lseek(ctl->fd, SIGNATURE_OFFSET, SEEK_SET) != SIGNATURE_OFFSET)
 334                 errx(EXIT_FAILURE, _("unable to rewind swap-device"));
 335
 336         if (write_all(ctl->fd, (char *) ctl->signature_page + SIGNATURE_OFFSET,
 337                       ctl->pagesize - SIGNATURE_OFFSET) == -1)
 338                 err(EXIT_FAILURE,
 339                         _("%s: unable to write signature page"),
 340                         ctl->devname);
 341 }
 342
 343 int main(int argc, char **argv)
 344 {
 345         struct mkswap_control ctl = { .fd = -1 };
 346         int c, permMask;
 347         uint64_t sz;
 348         int version = SWAP_VERSION;
 349         char *block_count = NULL, *strsz = NULL;
 350 #ifdef HAVE_LIBUUID
 351         const char *opt_uuid = NULL;
 352         uuid_t uuid_dat;
 353 #endif
 354         static const struct option longopts[] = {
 355                 { "check",       no_argument,       NULL, 'c' },
 356                 { "force",       no_argument,       NULL, 'f' },
 357                 { "pagesize",    required_argument, NULL, 'p' },
 358                 { "label",       required_argument, NULL, 'L' },
 359                 { "swapversion", required_argument, NULL, 'v' },
 360                 { "uuid",        required_argument, NULL, 'U' },
 361                 { "version",     no_argument,       NULL, 'V' },
 362                 { "help",        no_argument,       NULL, 'h' },
 363                 { NULL,          0, NULL, 0 }
 364         };
 365
 366         setlocale(LC_ALL, "");
 367         bindtextdomain(PACKAGE, LOCALEDIR);
 368         textdomain(PACKAGE);
 369         atexit(close_stdout);
 370
 371         while((c = getopt_long(argc, argv, "cfp:L:v:U:Vh", longopts, NULL)) != -1) {
 372                 switch (c) {
 373                 case 'c':
 374                         ctl.check = 1;
 375                         break;
 376                 case 'f':
 377                         ctl.force = 1;
 378                         break;
 379                 case 'p':
 380                         ctl.user_pagesize = strtou32_or_err(optarg, _("parsing page size failed"));
 381                         break;
 382                 case 'L':
 383                         ctl.opt_label = optarg;
 384                         break;
 385                 case 'v':
 386                         version = strtos32_or_err(optarg, _("parsing version number failed"));
 387                         if (version != SWAP_VERSION)
 388                                 errx(EXIT_FAILURE,
 389                                         _("swapspace version %d is not supported"), version);
 390                         break;
 391                 case 'U':
 392 #ifdef HAVE_LIBUUID
 393                         opt_uuid = optarg;
 394 #else
 395                         warnx(_("warning: ignoring -U (UUIDs are unsupported by %s)"),
 396                                 program_invocation_short_name);
 397 #endif
 398                         break;
 399                 case 'V':
 400                         printf(UTIL_LINUX_VERSION);
 401                         exit(EXIT_SUCCESS);
 402                 case 'h':
 403                         usage(stdout);
 404                 default:
 405                         errtryhelp(EXIT_FAILURE);
 406                 }
 407         }
 408
 409         if (optind < argc)
 410                 ctl.devname = argv[optind++];
 411         if (optind < argc)
 412                 block_count = argv[optind++];
 413         if (optind != argc) {
 414                 warnx(_("only one device argument is currently supported"));
 415                 usage(stderr);
 416         }
 417
 418 #ifdef HAVE_LIBUUID
 419         if(opt_uuid) {
 420                 if (uuid_parse(opt_uuid, uuid_dat) != 0)
 421                         errx(EXIT_FAILURE, _("error: parsing UUID failed"));
 422         } else
 423                 uuid_generate(uuid_dat);
 424         ctl.uuid = uuid_dat;
 425 #endif
 426
 427         init_signature_page(&ctl);      /* get pagesize and allocate signature page */
 428
 429         if (!ctl.devname) {
 430                 warnx(_("error: Nowhere to set up swap on?"));
 431                 usage(stderr);
 432         }
 433         if (block_count) {
 434                 /* this silly user specified the number of blocks explicitly */
 435                 uint64_t blks = strtou64_or_err(block_count,
 436                                         _("invalid block count argument"));
 437                 ctl.npages = blks / (ctl.pagesize / 1024);
 438         }
 439
 440         sz = get_size(&ctl);
 441         if (!ctl.npages)
 442                 ctl.npages = sz;
 443         else if (ctl.npages > sz && !ctl.force)
 444                 errx(EXIT_FAILURE,
 445                         _("error: "
 446                           "size %llu KiB is larger than device size %"PRIu64" KiB"),
 447                         ctl.npages * (ctl.pagesize / 1024), sz * (ctl.pagesize / 1024));
 448
 449         if (ctl.npages < MIN_GOODPAGES)
 450                 errx(EXIT_FAILURE,
 451                      _("error: swap area needs to be at least %ld KiB"),
 452                      (long)(MIN_GOODPAGES * ctl.pagesize / 1024));
 453         if (ctl.npages > UINT32_MAX) {
 454                 /* true when swap is bigger than 17.59 terabytes */
 455                 ctl.npages = UINT32_MAX;
 456                 warnx(_("warning: truncating swap area to %llu KiB"),
 457                         ctl.npages * ctl.pagesize / 1024);
 458         }
 459
 460         if (is_mounted(ctl.devname))
 461                 errx(EXIT_FAILURE, _("error: "
 462                         "%s is mounted; will not make swapspace"),
 463                         ctl.devname);
 464
 465         open_device(&ctl);
 466         permMask = S_ISBLK(ctl.devstat.st_mode) ? 07007 : 07077;
 467         if ((ctl.devstat.st_mode & permMask) != 0)
 468                 warnx(_("%s: insecure permissions %04o, %04o suggested."),
 469                         ctl.devname, ctl.devstat.st_mode & 07777,
 470                         ~permMask & 0666);
 471         if (getuid() == 0 && S_ISREG(ctl.devstat.st_mode) && ctl.devstat.st_uid != 0)
 472                 warnx(_("%s: insecure file owner %d, 0 (root) suggested."),
 473                         ctl.devname, ctl.devstat.st_uid);
 474
 475
 476         if (ctl.check)
 477                 check_blocks(&ctl);
 478
 479         wipe_device(&ctl);
 480
 481         assert(ctl.hdr);
 482         ctl.hdr->version = version;
 483         ctl.hdr->last_page = ctl.npages - 1;
 484         ctl.hdr->nr_badpages = ctl.nbadpages;
 485
 486         if ((ctl.npages - MIN_GOODPAGES) < ctl.nbadpages)
 487                 errx(EXIT_FAILURE, _("Unable to set up swap-space: unreadable"));
 488
 489         sz = (ctl.npages - ctl.nbadpages - 1) * ctl.pagesize;
 490         strsz = size_to_human_string(SIZE_SUFFIX_SPACE | SIZE_SUFFIX_3LETTER, sz);
 491
 492         printf(_("Setting up swapspace version %d, size = %s (%"PRIu64" bytes)\n"),
 493                 version, strsz, sz);
 494         free(strsz);
 495
 496         set_signature(&ctl);
 497         set_uuid_and_label(&ctl);
 498
 499         write_header_to_device(&ctl);
 500
 501         deinit_signature_page(&ctl);
 502
 503 #ifdef HAVE_LIBSELINUX
 504         if (S_ISREG(ctl.devstat.st_mode) && is_selinux_enabled() > 0) {
 505                 security_context_t context_string;
 506                 security_context_t oldcontext;
 507                 context_t newcontext;
 508
 509                 if (fgetfilecon(ctl.fd, &oldcontext) < 0) {
 510                         if (errno != ENODATA)
 511                                 err(EXIT_FAILURE,
 512                                         _("%s: unable to obtain selinux file label"),
 513                                         ctl.devname);
 514                         if (matchpathcon(ctl.devname, ctl.devstat.st_mode, &oldcontext))
 515                                 errx(EXIT_FAILURE, _("unable to matchpathcon()"));
 516                 }
 517                 if (!(newcontext = context_new(oldcontext)))
 518                         errx(EXIT_FAILURE, _("unable to create new selinux context"));
 519                 if (context_type_set(newcontext, SELINUX_SWAPFILE_TYPE))
 520                         errx(EXIT_FAILURE, _("couldn't compute selinux context"));
 521
 522                 context_string = context_str(newcontext);
 523
 524                 if (strcmp(context_string, oldcontext)!=0) {
 525                         if (fsetfilecon(ctl.fd, context_string) && errno != ENOTSUP)
 526                                 err(EXIT_FAILURE, _("unable to relabel %s to %s"),
 527                                                 ctl.devname, context_string);
 528                 }
 529                 context_free(newcontext);
 530                 freecon(oldcontext);
 531         }
 532 #endif
 533         /*
 534          * A subsequent swapon() will fail if the signature
 535          * is not actually on disk. (This is a kernel bug.)
 536          * The fsync() in close_fd() will take care of writing.
 537          */
 538         if (close_fd(ctl.fd) != 0)
 539                 err(EXIT_FAILURE, _("write failed"));
 540         return EXIT_SUCCESS;
 541 }