mdopen.c

   1 /*
   2  * mdadm - manage Linux "md" devices aka RAID arrays.
   3  *
   4  * Copyright (C) 2001-2013 Neil Brown <neilb@suse.de>
   5  *
   6  *
   7  *    This program is free software; you can redistribute it and/or modify
   8  *    it under the terms of the GNU General Public License as published by
   9  *    the Free Software Foundation; either version 2 of the License, or
  10  *    (at your option) any later version.
  11  *
  12  *    This program is distributed in the hope that it will be useful,
  13  *    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *    GNU General Public License for more details.
  16  *
  17  *    You should have received a copy of the GNU General Public License
  18  *    along with this program; if not, write to the Free Software
  19  *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  *
  21  *    Author: Neil Brown
  22  *    Email: <neilb@suse.de>
  23  */
  24
  25 #include "mdadm.h"
  26 #include "md_p.h"
  27 #include <ctype.h>
  28
  29 void make_parts(char *dev, int cnt)
  30 {
  31         /* make 'cnt' partition devices for 'dev'
  32          * If dev is a device name we use the
  33          *  major/minor from dev and add 1..cnt
  34          * If it is a symlink, we make similar symlinks.
  35          * If dev ends with a digit, we add "p%d" else "%d"
  36          * If the name exists, we use it's owner/mode,
  37          * else that of dev
  38          */
  39         struct stat stb;
  40         int major_num;
  41         int minor_num;
  42         int odig;
  43         int i;
  44         int nlen = strlen(dev) + 20;
  45         char *name;
  46         int dig = isdigit(dev[strlen(dev)-1]);
  47         char orig[1001];
  48         char sym[1024];
  49         int err;
  50
  51         if (cnt == 0)
  52                 cnt = 4;
  53         if (lstat(dev, &stb)!= 0)
  54                 return;
  55
  56         if (S_ISBLK(stb.st_mode)) {
  57                 major_num = major(stb.st_rdev);
  58                 minor_num = minor(stb.st_rdev);
  59                 odig = -1;
  60         } else if (S_ISLNK(stb.st_mode)) {
  61                 int len;
  62
  63                 len = readlink(dev, orig, sizeof(orig));
  64                 if (len < 0 || len >= (int)sizeof(orig))
  65                         return;
  66                 orig[len] = 0;
  67                 odig = isdigit(orig[len-1]);
  68                 major_num = -1;
  69                 minor_num = -1;
  70         } else
  71                 return;
  72         name = xmalloc(nlen);
  73         for (i = 1; i <= cnt ; i++) {
  74                 struct stat stb2;
  75                 snprintf(name, nlen, "%s%s%d", dev, dig?"p":"", i);
  76                 if (stat(name, &stb2) == 0) {
  77                         if (!S_ISBLK(stb2.st_mode) || !S_ISBLK(stb.st_mode))
  78                                 continue;
  79                         if (stb2.st_rdev == makedev(major_num, minor_num+i))
  80                                 continue;
  81                         unlink(name);
  82                 } else {
  83                         stb2 = stb;
  84                 }
  85                 if (S_ISBLK(stb.st_mode)) {
  86                         if (mknod(name, S_IFBLK | 0600,
  87                                   makedev(major_num, minor_num+i)))
  88                                 perror("mknod");
  89                         if (chown(name, stb2.st_uid, stb2.st_gid))
  90                                 perror("chown");
  91                         if (chmod(name, stb2.st_mode & 07777))
  92                                 perror("chmod");
  93                         err = 0;
  94                 } else {
  95                         snprintf(sym, sizeof(sym), "%s%s%d", orig, odig?"p":"", i);
  96                         err = symlink(sym, name);
  97                 }
  98
  99                 if (err == 0 && stat(name, &stb2) == 0)
 100                         add_dev(name, &stb2, 0, NULL);
 101         }
 102         free(name);
 103 }
 104
 105 int create_named_array(char *devnm)
 106 {
 107         int fd;
 108         int n = -1;
 109         static const char new_array_file[] = {
 110                 "/sys/module/md_mod/parameters/new_array"
 111         };
 112
 113         fd = open(new_array_file, O_WRONLY);
 114         if (fd < 0 && errno == ENOENT) {
 115                 if (system("modprobe md_mod") == 0)
 116                         fd = open(new_array_file, O_WRONLY);
 117         }
 118         if (fd >= 0) {
 119                 n = write(fd, devnm, strlen(devnm));
 120                 close(fd);
 121         }
 122         if (fd < 0 || n != (int)strlen(devnm)) {
 123                 pr_err("Fail to create %s when using %s, fallback to creation via node\n",
 124                         devnm, new_array_file);
 125                 return 0;
 126         }
 127
 128         return 1;
 129 }
 130
 131 /*
 132  * We need a new md device to assemble/build/create an array.
 133  * 'dev' is a name given us by the user (command line or mdadm.conf)
 134  * It might start with /dev or /dev/md any might end with a digit
 135  * string.
 136  * If it starts with just /dev, it must be /dev/mdX or /dev/md_dX
 137  * If it ends with a digit string, then it must be as above, or
 138  * 'trustworthy' must be 'METADATA' and the 'dev' must be
 139  *  /dev/md/'name'NN or 'name'NN
 140  * If it doesn't end with a digit string, it must be /dev/md/'name'
 141  * or 'name' or must be NULL.
 142  * If the digit string is present, it gives the minor number to use
 143  * If not, we choose a high, unused minor number.
 144  * If the 'dev' is a standard name, it devices whether 'md' or 'mdp'.
 145  * else if the name is 'd[0-9]+' then we use mdp
 146  * else if trustworthy is 'METADATA' we use md
 147  * else the choice depends on 'autof'.
 148  * If name is NULL it is assumed to match whatever dev provides.
 149  * If both name and dev are NULL, we choose a name 'mdXX' or 'mdpXX'
 150  *
 151  * If 'name' is given, and 'trustworthy' is 'foreign' and name is not
 152  * supported by 'dev', we add a "_%d" suffix based on the minor number
 153  * use that.
 154  *
 155  * If udev is configured, we create a temporary device, open it, and
 156  * unlink it.
 157  * If not, we create the /dev/mdXX device, and if name is usable,
 158  * /dev/md/name
 159  * In any case we return /dev/md/name or (if that isn't available)
 160  * /dev/mdXX in 'chosen'.
 161  *
 162  * When we create devices, we use uid/gid/umask from config file.
 163  */
 164
 165 int create_mddev(char *dev, char *name, int autof, int trustworthy,
 166                  char *chosen, int block_udev)
 167 {
 168         int mdfd;
 169         struct stat stb;
 170         int num = -1;
 171         int use_mdp = -1;
 172         struct createinfo *ci = conf_get_create_info();
 173         int parts;
 174         char *cname;
 175         char devname[37];
 176         char devnm[32];
 177         char cbuf[400];
 178
 179         if (!use_udev())
 180                 block_udev = 0;
 181
 182         if (chosen == NULL)
 183                 chosen = cbuf;
 184
 185         if (autof == 0)
 186                 autof = ci->autof;
 187
 188         parts = autof >> 3;
 189         autof &= 7;
 190
 191         strcpy(chosen, "/dev/md/");
 192         cname = chosen + strlen(chosen);
 193
 194         if (dev) {
 195                 if (strncmp(dev, "/dev/md/", 8) == 0) {
 196                         strcpy(cname, dev+8);
 197                 } else if (strncmp(dev, "/dev/", 5) == 0) {
 198                         char *e = dev + strlen(dev);
 199                         while (e > dev && isdigit(e[-1]))
 200                                 e--;
 201                         if (e[0])
 202                                 num = strtoul(e, NULL, 10);
 203                         strcpy(cname, dev+5);
 204                         cname[e-(dev+5)] = 0;
 205                         /* name *must* be mdXX or md_dXX in this context */
 206                         if (num < 0 ||
 207                             (strcmp(cname, "md") != 0 && strcmp(cname, "md_d") != 0)) {
 208                                 pr_err("%s is an invalid name for an md device.  Try /dev/md/%s\n",
 209                                         dev, dev+5);
 210                                 return -1;
 211                         }
 212                         if (strcmp(cname, "md") == 0)
 213                                 use_mdp = 0;
 214                         else
 215                                 use_mdp = 1;
 216                         /* recreate name: /dev/md/0 or /dev/md/d0 */
 217                         sprintf(cname, "%s%d", use_mdp?"d":"", num);
 218                 } else
 219                         strcpy(cname, dev);
 220
 221                 /* 'cname' must not contain a slash, and may not be
 222                  * empty.
 223                  */
 224                 if (strchr(cname, '/') != NULL) {
 225                         pr_err("%s is an invalid name for an md device.\n", dev);
 226                         return -1;
 227                 }
 228                 if (cname[0] == 0) {
 229                         pr_err("%s is an invalid name for an md device (empty!).\n", dev);
 230                         return -1;
 231                 }
 232                 if (num < 0) {
 233                         /* If cname  is 'N' or 'dN', we get dev number
 234                          * from there.
 235                          */
 236                         char *sp = cname;
 237                         char *ep;
 238                         if (cname[0] == 'd')
 239                                 sp++;
 240                         if (isdigit(sp[0]))
 241                                 num = strtoul(sp, &ep, 10);
 242                         else
 243                                 ep = sp;
 244                         if (ep == sp || *ep || num < 0)
 245                                 num = -1;
 246                         else if (cname[0] == 'd')
 247                                 use_mdp = 1;
 248                         else
 249                                 use_mdp = 0;
 250                 }
 251         }
 252
 253         /* Now determine device number */
 254         /* named 'METADATA' cannot use 'mdp'. */
 255         if (name && name[0] == 0)
 256                 name = NULL;
 257         if (name && trustworthy == METADATA && use_mdp == 1) {
 258                 pr_err("%s is not allowed for a %s container. Consider /dev/md%d.\n", dev, name, num);
 259                 return -1;
 260         }
 261         if (name && trustworthy == METADATA)
 262                 use_mdp = 0;
 263         if (use_mdp == -1) {
 264                 if (autof == 4 || autof == 6)
 265                         use_mdp = 1;
 266                 else
 267                         use_mdp = 0;
 268         }
 269         if (num < 0 && trustworthy == LOCAL && name) {
 270                 /* if name is numeric, possibly prefixed by
 271                  * 'md' or '/dev/md', use that for num
 272                  * if it is not already in use */
 273                 char *ep;
 274                 char *n2 = name;
 275                 if (strncmp(n2, "/dev/", 5) == 0)
 276                         n2 += 5;
 277                 if (strncmp(n2, "md", 2) == 0)
 278                         n2 += 2;
 279                 if (*n2 == '/')
 280                         n2++;
 281                 num = strtoul(n2, &ep, 10);
 282                 if (ep == n2 || *ep)
 283                         num = -1;
 284                 else {
 285                         sprintf(devnm, "md%s%d", use_mdp ? "_d":"", num);
 286                         if (mddev_busy(devnm))
 287                                 num = -1;
 288                 }
 289         }
 290
 291         if (cname[0] == 0 && name) {
 292                 /* Need to find a name if we can
 293                  * We don't completely trust 'name'.  Truncate to
 294                  * reasonable length and remove '/'
 295                  */
 296                 char *cp;
 297                 struct map_ent *map = NULL;
 298                 int conflict = 1;
 299                 int unum = 0;
 300                 int cnlen;
 301                 strncpy(cname, name, 200);
 302                 cname[200] = 0;
 303                 for (cp = cname; *cp ; cp++)
 304                         switch (*cp) {
 305                         case '/':
 306                                 *cp = '-';
 307                                 break;
 308                         case ' ':
 309                         case '\t':
 310                                 *cp = '_';
 311                                 break;
 312                         }
 313
 314                 if (trustworthy == LOCAL ||
 315                     (trustworthy == FOREIGN && strchr(cname, ':') != NULL)) {
 316                         /* Only need suffix if there is a conflict */
 317                         if (map_by_name(&map, cname) == NULL)
 318                                 conflict = 0;
 319                 }
 320                 cnlen = strlen(cname);
 321                 while (conflict) {
 322                         if (trustworthy == METADATA && !isdigit(cname[cnlen-1]))
 323                                 sprintf(cname+cnlen, "%d", unum);
 324                         else
 325                                 /* add _%d to FOREIGN array that don't
 326                                  * a 'host:' prefix
 327                                  */
 328                                 sprintf(cname+cnlen, "_%d", unum);
 329                         unum++;
 330                         if (map_by_name(&map, cname) == NULL)
 331                                 conflict = 0;
 332                 }
 333         }
 334
 335         devnm[0] = 0;
 336         if (num < 0 && cname && ci->names) {
 337                 sprintf(devnm, "md_%s", cname);
 338                 if (block_udev)
 339                         udev_block(devnm);
 340                 if (!create_named_array(devnm)) {
 341                         devnm[0] = 0;
 342                         udev_unblock();
 343                 }
 344         }
 345         if (num >= 0) {
 346                 sprintf(devnm, "md%d", num);
 347                 if (block_udev)
 348                         udev_block(devnm);
 349                 if (!create_named_array(devnm)) {
 350                         devnm[0] = 0;
 351                         udev_unblock();
 352                 }
 353         }
 354         if (devnm[0] == 0) {
 355                 if (num < 0) {
 356                         /* need to choose a free number. */
 357                         char *_devnm = find_free_devnm(use_mdp);
 358                         if (_devnm == NULL) {
 359                                 pr_err("No avail md devices - aborting\n");
 360                                 return -1;
 361                         }
 362                         strcpy(devnm, _devnm);
 363                 } else {
 364                         sprintf(devnm, "%s%d", use_mdp?"md_d":"md", num);
 365                         if (mddev_busy(devnm)) {
 366                                 pr_err("%s is already in use.\n",
 367                                        dev);
 368                                 return -1;
 369                         }
 370                 }
 371                 if (block_udev)
 372                         udev_block(devnm);
 373         }
 374
 375         sprintf(devname, "/dev/%s", devnm);
 376
 377         if (dev && dev[0] == '/')
 378                 strcpy(chosen, dev);
 379         else if (cname[0] == 0)
 380                 strcpy(chosen, devname);
 381
 382         /* We have a device number and name.
 383          * If we cannot detect udev, we need to make
 384          * devices and links ourselves.
 385          */
 386         if (!use_udev()) {
 387                 /* Make sure 'devname' exists and 'chosen' is a symlink to it */
 388                 if (lstat(devname, &stb) == 0) {
 389                         /* Must be the correct device, else error */
 390                         if ((stb.st_mode&S_IFMT) != S_IFBLK ||
 391                             stb.st_rdev != devnm2devid(devnm)) {
 392                                 pr_err("%s exists but looks wrong, please fix\n",
 393                                         devname);
 394                                 return -1;
 395                         }
 396                 } else {
 397                         if (mknod(devname, S_IFBLK|0600,
 398                                   devnm2devid(devnm)) != 0) {
 399                                 pr_err("failed to create %s\n",
 400                                         devname);
 401                                 return -1;
 402                         }
 403                         if (chown(devname, ci->uid, ci->gid))
 404                                 perror("chown");
 405                         if (chmod(devname, ci->mode))
 406                                 perror("chmod");
 407                         stat(devname, &stb);
 408                         add_dev(devname, &stb, 0, NULL);
 409                 }
 410                 if (use_mdp == 1)
 411                         make_parts(devname, parts);
 412
 413                 if (strcmp(chosen, devname) != 0) {
 414                         if (mkdir("/dev/md",0700) == 0) {
 415                                 if (chown("/dev/md", ci->uid, ci->gid))
 416                                         perror("chown /dev/md");
 417                                 if (chmod("/dev/md", ci->mode| ((ci->mode>>2) & 0111)))
 418                                         perror("chmod /dev/md");
 419                         }
 420
 421                         if (dev && strcmp(chosen, dev) == 0)
 422                                 /* We know we are allowed to use this name */
 423                                 unlink(chosen);
 424
 425                         if (lstat(chosen, &stb) == 0) {
 426                                 char buf[300];
 427                                 ssize_t link_len = readlink(chosen, buf, sizeof(buf)-1);
 428                                 if (link_len >= 0)
 429                                         buf[link_len] = '\0';
 430
 431                                 if ((stb.st_mode & S_IFMT) != S_IFLNK ||
 432                                     link_len < 0 ||
 433                                     strcmp(buf, devname) != 0) {
 434                                         pr_err("%s exists - ignoring\n",
 435                                                 chosen);
 436                                         strcpy(chosen, devname);
 437                                 }
 438                         } else if (symlink(devname, chosen) != 0)
 439                                 pr_err("failed to create %s: %s\n",
 440                                         chosen, strerror(errno));
 441                         if (use_mdp && strcmp(chosen, devname) != 0)
 442                                 make_parts(chosen, parts);
 443                 }
 444         }
 445         mdfd = open_dev_excl(devnm);
 446         if (mdfd < 0)
 447                 pr_err("unexpected failure opening %s\n",
 448                         devname);
 449         return mdfd;
 450 }
 451
 452 /* Open this and check that it is an md device.
 453  * On success, return filedescriptor.
 454  * On failure, return -1 if it doesn't exist,
 455  * or -2 if it exists but is not an md device.
 456  */
 457 int open_mddev(char *dev, int report_errors)
 458 {
 459         int mdfd = open(dev, O_RDONLY);
 460
 461         if (mdfd < 0) {
 462                 if (report_errors)
 463                         pr_err("error opening %s: %s\n",
 464                                 dev, strerror(errno));
 465                 return -1;
 466         }
 467
 468         if (md_array_valid(mdfd) == 0) {
 469                 close(mdfd);
 470                 if (report_errors)
 471                         pr_err("%s does not appear to be an md device\n", dev);
 472                 return -2;
 473         }
 474
 475         return mdfd;
 476 }
 477
 478 char *find_free_devnm(int use_partitions)
 479 {
 480         static char devnm[32];
 481         int devnum;
 482         for (devnum = 127; devnum != 128;
 483              devnum = devnum ? devnum-1 : (1<<9)-1) {
 484
 485                 if (use_partitions)
 486                         sprintf(devnm, "md_d%d", devnum);
 487                 else
 488                         sprintf(devnm, "md%d", devnum);
 489                 if (mddev_busy(devnm))
 490                         continue;
 491                 if (!conf_name_is_free(devnm))
 492                         continue;
 493                 if (!use_udev()) {
 494                         /* make sure it is new to /dev too, at least as a
 495                          * non-standard */
 496                         dev_t devid = devnm2devid(devnm);
 497                         if (devid) {
 498                                 char *dn = map_dev(major(devid),
 499                                                    minor(devid), 0);
 500                                 if (dn && ! is_standard(dn, NULL))
 501                                         continue;
 502                         }
 503                 }
 504                 break;
 505         }
 506         if (devnum == 128)
 507                 return NULL;
 508         return devnm;
 509 }