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 "udev.h"
  27 #include "md_p.h"
  28 #include <ctype.h>
  29
  30 void make_parts(char *dev, int cnt)
  31 {
  32         /* make 'cnt' partition devices for 'dev'
  33          * If dev is a device name we use the
  34          *  major/minor from dev and add 1..cnt
  35          * If it is a symlink, we make similar symlinks.
  36          * If dev ends with a digit, we add "p%d" else "%d"
  37          * If the name exists, we use it's owner/mode,
  38          * else that of dev
  39          */
  40         struct stat stb;
  41         int major_num;
  42         int minor_num;
  43         int odig;
  44         int i;
  45         int nlen = strlen(dev) + 20;
  46         char *name;
  47         int dig = isdigit(dev[strlen(dev)-1]);
  48         char orig[1001];
  49         char sym[1024];
  50         int err;
  51
  52         if (cnt == 0)
  53                 cnt = 4;
  54         if (lstat(dev, &stb)!= 0)
  55                 return;
  56
  57         if (S_ISBLK(stb.st_mode)) {
  58                 major_num = major(stb.st_rdev);
  59                 minor_num = minor(stb.st_rdev);
  60                 odig = -1;
  61         } else if (S_ISLNK(stb.st_mode)) {
  62                 int len;
  63
  64                 len = readlink(dev, orig, sizeof(orig));
  65                 if (len < 0 || len >= (int)sizeof(orig))
  66                         return;
  67                 orig[len] = 0;
  68                 odig = isdigit(orig[len-1]);
  69                 major_num = -1;
  70                 minor_num = -1;
  71         } else
  72                 return;
  73         name = xmalloc(nlen);
  74         for (i = 1; i <= cnt ; i++) {
  75                 struct stat stb2;
  76                 snprintf(name, nlen, "%s%s%d", dev, dig?"p":"", i);
  77                 if (stat(name, &stb2) == 0) {
  78                         if (!S_ISBLK(stb2.st_mode) || !S_ISBLK(stb.st_mode))
  79                                 continue;
  80                         if (stb2.st_rdev == makedev(major_num, minor_num+i))
  81                                 continue;
  82                         unlink(name);
  83                 } else {
  84                         stb2 = stb;
  85                 }
  86                 if (S_ISBLK(stb.st_mode)) {
  87                         if (mknod(name, S_IFBLK | 0600,
  88                                   makedev(major_num, minor_num+i)))
  89                                 perror("mknod");
  90                         if (chown(name, stb2.st_uid, stb2.st_gid))
  91                                 perror("chown");
  92                         if (chmod(name, stb2.st_mode & 07777))
  93                                 perror("chmod");
  94                         err = 0;
  95                 } else {
  96                         snprintf(sym, sizeof(sym), "%s%s%d", orig, odig?"p":"", i);
  97                         err = symlink(sym, name);
  98                 }
  99
 100                 if (err == 0 && stat(name, &stb2) == 0)
 101                         add_dev(name, &stb2, 0, NULL);
 102         }
 103         free(name);
 104 }
 105
 106 int create_named_array(char *devnm)
 107 {
 108         int fd;
 109         int n = -1;
 110         static const char new_array_file[] = {
 111                 "/sys/module/md_mod/parameters/new_array"
 112         };
 113
 114         fd = open(new_array_file, O_WRONLY);
 115         if (fd < 0 && errno == ENOENT) {
 116                 if (system("modprobe md_mod") == 0)
 117                         fd = open(new_array_file, O_WRONLY);
 118         }
 119         if (fd >= 0) {
 120                 n = write(fd, devnm, strlen(devnm));
 121                 close(fd);
 122         }
 123         if (fd < 0 || n != (int)strlen(devnm)) {
 124                 pr_err("Fail to create %s when using %s, fallback to creation via node\n",
 125                         devnm, new_array_file);
 126                 return 0;
 127         }
 128
 129         return 1;
 130 }
 131
 132 /*
 133  * We need a new md device to assemble/build/create an array.
 134  * 'dev' is a name given us by the user (command line or mdadm.conf)
 135  * It might start with /dev or /dev/md any might end with a digit
 136  * string.
 137  * If it starts with just /dev, it must be /dev/mdX or /dev/md_dX
 138  * If it ends with a digit string, then it must be as above, or
 139  * 'trustworthy' must be 'METADATA' and the 'dev' must be
 140  *  /dev/md/'name'NN or 'name'NN
 141  * If it doesn't end with a digit string, it must be /dev/md/'name'
 142  * or 'name' or must be NULL.
 143  * If the digit string is present, it gives the minor number to use
 144  * If not, we choose a high, unused minor number.
 145  * If the 'dev' is a standard name, it devices whether 'md' or 'mdp'.
 146  * else if the name is 'd[0-9]+' then we use mdp
 147  * else if trustworthy is 'METADATA' we use md
 148  * else the choice depends on 'autof'.
 149  * If name is NULL it is assumed to match whatever dev provides.
 150  * If both name and dev are NULL, we choose a name 'mdXX' or 'mdpXX'
 151  *
 152  * If 'name' is given, and 'trustworthy' is 'foreign' and name is not
 153  * supported by 'dev', we add a "_%d" suffix based on the minor number
 154  * use that.
 155  *
 156  * If udev is configured, we create a temporary device, open it, and
 157  * unlink it.
 158  * If not, we create the /dev/mdXX device, and if name is usable,
 159  * /dev/md/name
 160  * In any case we return /dev/md/name or (if that isn't available)
 161  * /dev/mdXX in 'chosen'.
 162  *
 163  * When we create devices, we use uid/gid/umask from config file.
 164  */
 165
 166 int create_mddev(char *dev, char *name, int autof, int trustworthy,
 167                  char *chosen, int block_udev)
 168 {
 169         int mdfd;
 170         struct stat stb;
 171         int num = -1;
 172         int use_mdp = -1;
 173         struct createinfo *ci = conf_get_create_info();
 174         int parts;
 175         char *cname;
 176         char devname[37];
 177         char devnm[32];
 178         char cbuf[400];
 179
 180         if (!udev_is_available())
 181                 block_udev = 0;
 182
 183         if (chosen == NULL)
 184                 chosen = cbuf;
 185
 186         if (autof == 0)
 187                 autof = ci->autof;
 188
 189         parts = autof >> 3;
 190         autof &= 7;
 191
 192         strcpy(chosen, DEV_MD_DIR);
 193         cname = chosen + strlen(chosen);
 194
 195         if (dev) {
 196                 if (strncmp(dev, DEV_MD_DIR, DEV_MD_DIR_LEN) == 0) {
 197                         snprintf(cname, MD_NAME_MAX, "%s", dev + DEV_MD_DIR_LEN);
 198                 } else if (strncmp(dev, "/dev/", 5) == 0) {
 199                         char *e = dev + strlen(dev);
 200                         while (e > dev && isdigit(e[-1]))
 201                                 e--;
 202                         if (e[0])
 203                                 num = strtoul(e, NULL, 10);
 204                         snprintf(cname, MD_NAME_MAX, "%s", dev + 5);
 205                         cname[e-(dev+5)] = 0;
 206                         /* name *must* be mdXX or md_dXX in this context */
 207                         if (num < 0 ||
 208                             (strcmp(cname, "md") != 0 && strcmp(cname, "md_d") != 0)) {
 209                                 pr_err("%s is an invalid name for an md device.  Try /dev/md/%s\n",
 210                                         dev, dev+5);
 211                                 return -1;
 212                         }
 213                         if (strcmp(cname, "md") == 0)
 214                                 use_mdp = 0;
 215                         else
 216                                 use_mdp = 1;
 217                         /* recreate name: /dev/md/0 or /dev/md/d0 */
 218                         sprintf(cname, "%s%d", use_mdp?"d":"", num);
 219                 } else
 220                         strcpy(cname, dev);
 221
 222                 /* 'cname' must not contain a slash, and may not be
 223                  * empty.
 224                  */
 225                 if (strchr(cname, '/') != NULL) {
 226                         pr_err("%s is an invalid name for an md device.\n", dev);
 227                         return -1;
 228                 }
 229                 if (cname[0] == 0) {
 230                         pr_err("%s is an invalid name for an md device (empty!).\n", dev);
 231                         return -1;
 232                 }
 233                 if (num < 0) {
 234                         /* If cname  is 'N' or 'dN', we get dev number
 235                          * from there.
 236                          */
 237                         char *sp = cname;
 238                         char *ep;
 239                         if (cname[0] == 'd')
 240                                 sp++;
 241                         if (isdigit(sp[0]))
 242                                 num = strtoul(sp, &ep, 10);
 243                         else
 244                                 ep = sp;
 245                         if (ep == sp || *ep || num < 0)
 246                                 num = -1;
 247                         else if (cname[0] == 'd')
 248                                 use_mdp = 1;
 249                         else
 250                                 use_mdp = 0;
 251                 }
 252         }
 253
 254         /* Now determine device number */
 255         /* named 'METADATA' cannot use 'mdp'. */
 256         if (name && name[0] == 0)
 257                 name = NULL;
 258         if (name && trustworthy == METADATA && use_mdp == 1) {
 259                 pr_err("%s is not allowed for a %s container. Consider /dev/md%d.\n", dev, name, num);
 260                 return -1;
 261         }
 262         if (name && trustworthy == METADATA)
 263                 use_mdp = 0;
 264         if (use_mdp == -1) {
 265                 if (autof == 4 || autof == 6)
 266                         use_mdp = 1;
 267                 else
 268                         use_mdp = 0;
 269         }
 270         if (num < 0 && trustworthy == LOCAL && name) {
 271                 /* if name is numeric, possibly prefixed by
 272                  * 'md' or '/dev/md', use that for num
 273                  * if it is not already in use */
 274                 char *ep;
 275                 char *n2 = name;
 276                 if (strncmp(n2, "/dev/", 5) == 0)
 277                         n2 += 5;
 278                 if (strncmp(n2, "md", 2) == 0)
 279                         n2 += 2;
 280                 if (*n2 == '/')
 281                         n2++;
 282                 num = strtoul(n2, &ep, 10);
 283                 if (ep == n2 || *ep)
 284                         num = -1;
 285                 else {
 286                         sprintf(devnm, "md%s%d", use_mdp ? "_d":"", num);
 287                         if (mddev_busy(devnm))
 288                                 num = -1;
 289                 }
 290         }
 291
 292         if (cname[0] == 0 && name) {
 293                 /* Need to find a name if we can
 294                  * We don't completely trust 'name'.  Truncate to
 295                  * reasonable length and remove '/'
 296                  */
 297                 char *cp;
 298                 struct map_ent *map = NULL;
 299                 int conflict = 1;
 300                 int unum = 0;
 301                 int cnlen;
 302                 strncpy(cname, name, 200);
 303                 cname[200] = 0;
 304                 for (cp = cname; *cp ; cp++)
 305                         switch (*cp) {
 306                         case '/':
 307                                 *cp = '-';
 308                                 break;
 309                         case ' ':
 310                         case '\t':
 311                                 *cp = '_';
 312                                 break;
 313                         }
 314
 315                 if (trustworthy == LOCAL ||
 316                     (trustworthy == FOREIGN && strchr(cname, ':') != NULL)) {
 317                         /* Only need suffix if there is a conflict */
 318                         if (map_by_name(&map, cname) == NULL)
 319                                 conflict = 0;
 320                 }
 321                 cnlen = strlen(cname);
 322                 while (conflict) {
 323                         if (trustworthy == METADATA && !isdigit(cname[cnlen-1]))
 324                                 sprintf(cname+cnlen, "%d", unum);
 325                         else
 326                                 /* add _%d to FOREIGN array that don't
 327                                  * a 'host:' prefix
 328                                  */
 329                                 sprintf(cname+cnlen, "_%d", unum);
 330                         unum++;
 331                         if (map_by_name(&map, cname) == NULL)
 332                                 conflict = 0;
 333                 }
 334         }
 335
 336         devnm[0] = 0;
 337         if (num < 0 && cname && ci->names) {
 338                 sprintf(devnm, "md_%s", cname);
 339                 if (block_udev)
 340                         udev_block(devnm);
 341                 if (!create_named_array(devnm)) {
 342                         devnm[0] = 0;
 343                         udev_unblock();
 344                 }
 345         }
 346         if (num >= 0) {
 347                 sprintf(devnm, "md%d", num);
 348                 if (block_udev)
 349                         udev_block(devnm);
 350                 if (!create_named_array(devnm)) {
 351                         devnm[0] = 0;
 352                         udev_unblock();
 353                 }
 354         }
 355         if (devnm[0] == 0) {
 356                 if (num < 0) {
 357                         /* need to choose a free number. */
 358                         char *_devnm = find_free_devnm(use_mdp);
 359                         if (_devnm == NULL) {
 360                                 pr_err("No avail md devices - aborting\n");
 361                                 return -1;
 362                         }
 363                         strcpy(devnm, _devnm);
 364                 } else {
 365                         sprintf(devnm, "%s%d", use_mdp?"md_d":"md", num);
 366                         if (mddev_busy(devnm)) {
 367                                 pr_err("%s is already in use.\n",
 368                                        dev);
 369                                 return -1;
 370                         }
 371                 }
 372                 if (block_udev)
 373                         udev_block(devnm);
 374                 create_named_array(devnm);
 375         }
 376
 377         sprintf(devname, "/dev/%s", devnm);
 378
 379         if (dev && dev[0] == '/')
 380                 strcpy(chosen, dev);
 381         else if (cname[0] == 0)
 382                 strcpy(chosen, devname);
 383
 384         /* We have a device number and name.
 385          * If we cannot detect udev, we need to make
 386          * devices and links ourselves.
 387          */
 388         if (!udev_is_available()) {
 389                 /* Make sure 'devname' exists and 'chosen' is a symlink to it */
 390                 if (lstat(devname, &stb) == 0) {
 391                         /* Must be the correct device, else error */
 392                         if ((stb.st_mode&S_IFMT) != S_IFBLK ||
 393                             stb.st_rdev != devnm2devid(devnm)) {
 394                                 pr_err("%s exists but looks wrong, please fix\n",
 395                                         devname);
 396                                 return -1;
 397                         }
 398                 } else {
 399                         if (mknod(devname, S_IFBLK|0600,
 400                                   devnm2devid(devnm)) != 0) {
 401                                 pr_err("failed to create %s\n",
 402                                         devname);
 403                                 return -1;
 404                         }
 405                         if (chown(devname, ci->uid, ci->gid))
 406                                 perror("chown");
 407                         if (chmod(devname, ci->mode))
 408                                 perror("chmod");
 409                         stat(devname, &stb);
 410                         add_dev(devname, &stb, 0, NULL);
 411                 }
 412                 if (use_mdp == 1)
 413                         make_parts(devname, parts);
 414
 415                 if (strcmp(chosen, devname) != 0) {
 416                         if (mkdir(DEV_NUM_PREF, 0700) == 0) {
 417                                 if (chown(DEV_NUM_PREF, ci->uid, ci->gid))
 418                                         perror("chown " DEV_NUM_PREF);
 419                                 if (chmod(DEV_NUM_PREF, ci->mode | ((ci->mode >> 2) & 0111)))
 420                                         perror("chmod " DEV_NUM_PREF);
 421                         }
 422
 423                         if (dev && strcmp(chosen, dev) == 0)
 424                                 /* We know we are allowed to use this name */
 425                                 unlink(chosen);
 426
 427                         if (lstat(chosen, &stb) == 0) {
 428                                 char buf[300];
 429                                 ssize_t link_len = readlink(chosen, buf, sizeof(buf)-1);
 430                                 if (link_len >= 0)
 431                                         buf[link_len] = '\0';
 432
 433                                 if ((stb.st_mode & S_IFMT) != S_IFLNK ||
 434                                     link_len < 0 ||
 435                                     strcmp(buf, devname) != 0) {
 436                                         pr_err("%s exists - ignoring\n",
 437                                                 chosen);
 438                                         strcpy(chosen, devname);
 439                                 }
 440                         } else if (symlink(devname, chosen) != 0)
 441                                 pr_err("failed to create %s: %s\n",
 442                                         chosen, strerror(errno));
 443                         if (use_mdp && strcmp(chosen, devname) != 0)
 444                                 make_parts(chosen, parts);
 445                 }
 446         }
 447         mdfd = open_dev_excl(devnm);
 448         if (mdfd < 0)
 449                 pr_err("unexpected failure opening %s\n",
 450                         devname);
 451         return mdfd;
 452 }
 453
 454 /* Open this and check that it is an md device.
 455  * On success, return filedescriptor.
 456  * On failure, return -1 if it doesn't exist,
 457  * or -2 if it exists but is not an md device.
 458  */
 459 int open_mddev(char *dev, int report_errors)
 460 {
 461         int mdfd = open(dev, O_RDONLY);
 462
 463         if (mdfd < 0) {
 464                 if (report_errors)
 465                         pr_err("error opening %s: %s\n",
 466                                 dev, strerror(errno));
 467                 return -1;
 468         }
 469
 470         if (md_array_valid(mdfd) == 0) {
 471                 close(mdfd);
 472                 if (report_errors)
 473                         pr_err("%s does not appear to be an md device\n", dev);
 474                 return -2;
 475         }
 476
 477         return mdfd;
 478 }
 479
 480 /**
 481  * is_mddev() - check that file name passed is an md device.
 482  * @dev: file name that has to be checked.
 483  * Return: 1 if file passed is an md device, 0 if not.
 484  */
 485 int is_mddev(char *dev)
 486 {
 487         int fd = open_mddev(dev, 1);
 488
 489         if (fd >= 0) {
 490                 close(fd);
 491                 return 1;
 492         }
 493
 494         return 0;
 495 }
 496
 497 char *find_free_devnm(int use_partitions)
 498 {
 499         static char devnm[32];
 500         int devnum;
 501         for (devnum = 127; devnum != 128;
 502              devnum = devnum ? devnum-1 : (1<<9)-1) {
 503
 504                 if (use_partitions)
 505                         sprintf(devnm, "md_d%d", devnum);
 506                 else
 507                         sprintf(devnm, "md%d", devnum);
 508                 if (mddev_busy(devnm))
 509                         continue;
 510                 if (!conf_name_is_free(devnm))
 511                         continue;
 512                 if (!udev_is_available()) {
 513                         /* make sure it is new to /dev too, at least as a
 514                          * non-standard */
 515                         dev_t devid = devnm2devid(devnm);
 516                         if (devid) {
 517                                 char *dn = map_dev(major(devid),
 518                                                    minor(devid), 0);
 519                                 if (dn && ! is_standard(dn, NULL))
 520                                         continue;
 521                         }
 522                 }
 523                 break;
 524         }
 525         if (devnum == 128)
 526                 return NULL;
 527         return devnm;
 528 }