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 create %s when using %s\n", devnm, new_array_file);
 124                 return 0;
 125         }
 126
 127         return 1;
 128 }
 129
 130 /*
 131  * We need a new md device to assemble/build/create an array.
 132  * 'dev' is a name given us by the user (command line or mdadm.conf)
 133  * It might start with /dev or /dev/md any might end with a digit
 134  * string.
 135  * If it starts with just /dev, it must be /dev/mdX or /dev/md_dX
 136  * If it ends with a digit string, then it must be as above, or
 137  * 'trustworthy' must be 'METADATA' and the 'dev' must be
 138  *  /dev/md/'name'NN or 'name'NN
 139  * If it doesn't end with a digit string, it must be /dev/md/'name'
 140  * or 'name' or must be NULL.
 141  * If the digit string is present, it gives the minor number to use
 142  * If not, we choose a high, unused minor number.
 143  * If the 'dev' is a standard name, it devices whether 'md' or 'mdp'.
 144  * else if the name is 'd[0-9]+' then we use mdp
 145  * else if trustworthy is 'METADATA' we use md
 146  * else the choice depends on 'autof'.
 147  * If name is NULL it is assumed to match whatever dev provides.
 148  * If both name and dev are NULL, we choose a name 'mdXX' or 'mdpXX'
 149  *
 150  * If 'name' is given, and 'trustworthy' is 'foreign' and name is not
 151  * supported by 'dev', we add a "_%d" suffix based on the minor number
 152  * use that.
 153  *
 154  * If udev is configured, we create a temporary device, open it, and
 155  * unlink it.
 156  * If not, we create the /dev/mdXX device, and if name is usable,
 157  * /dev/md/name
 158  * In any case we return /dev/md/name or (if that isn't available)
 159  * /dev/mdXX in 'chosen'.
 160  *
 161  * When we create devices, we use uid/gid/umask from config file.
 162  */
 163
 164 int create_mddev(char *dev, char *name, int autof, int trustworthy,
 165                  char *chosen, int block_udev)
 166 {
 167         int mdfd;
 168         struct stat stb;
 169         int num = -1;
 170         int use_mdp = -1;
 171         struct createinfo *ci = conf_get_create_info();
 172         int parts;
 173         char *cname;
 174         char devname[37];
 175         char devnm[32];
 176         char cbuf[400];
 177
 178         if (!use_udev())
 179                 block_udev = 0;
 180
 181         if (chosen == NULL)
 182                 chosen = cbuf;
 183
 184         if (autof == 0)
 185                 autof = ci->autof;
 186
 187         parts = autof >> 3;
 188         autof &= 7;
 189
 190         strcpy(chosen, "/dev/md/");
 191         cname = chosen + strlen(chosen);
 192
 193         if (dev) {
 194                 if (strncmp(dev, "/dev/md/", 8) == 0) {
 195                         strcpy(cname, dev+8);
 196                 } else if (strncmp(dev, "/dev/", 5) == 0) {
 197                         char *e = dev + strlen(dev);
 198                         while (e > dev && isdigit(e[-1]))
 199                                 e--;
 200                         if (e[0])
 201                                 num = strtoul(e, NULL, 10);
 202                         strcpy(cname, dev+5);
 203                         cname[e-(dev+5)] = 0;
 204                         /* name *must* be mdXX or md_dXX in this context */
 205                         if (num < 0 ||
 206                             (strcmp(cname, "md") != 0 && strcmp(cname, "md_d") != 0)) {
 207                                 pr_err("%s is an invalid name for an md device.  Try /dev/md/%s\n",
 208                                         dev, dev+5);
 209                                 return -1;
 210                         }
 211                         if (strcmp(cname, "md") == 0)
 212                                 use_mdp = 0;
 213                         else
 214                                 use_mdp = 1;
 215                         /* recreate name: /dev/md/0 or /dev/md/d0 */
 216                         sprintf(cname, "%s%d", use_mdp?"d":"", num);
 217                 } else
 218                         strcpy(cname, dev);
 219
 220                 /* 'cname' must not contain a slash, and may not be
 221                  * empty.
 222                  */
 223                 if (strchr(cname, '/') != NULL) {
 224                         pr_err("%s is an invalid name for an md device.\n", dev);
 225                         return -1;
 226                 }
 227                 if (cname[0] == 0) {
 228                         pr_err("%s is an invalid name for an md device (empty!).\n", dev);
 229                         return -1;
 230                 }
 231                 if (num < 0) {
 232                         /* If cname  is 'N' or 'dN', we get dev number
 233                          * from there.
 234                          */
 235                         char *sp = cname;
 236                         char *ep;
 237                         if (cname[0] == 'd')
 238                                 sp++;
 239                         if (isdigit(sp[0]))
 240                                 num = strtoul(sp, &ep, 10);
 241                         else
 242                                 ep = sp;
 243                         if (ep == sp || *ep || num < 0)
 244                                 num = -1;
 245                         else if (cname[0] == 'd')
 246                                 use_mdp = 1;
 247                         else
 248                                 use_mdp = 0;
 249                 }
 250         }
 251
 252         /* Now determine device number */
 253         /* named 'METADATA' cannot use 'mdp'. */
 254         if (name && name[0] == 0)
 255                 name = NULL;
 256         if (name && trustworthy == METADATA && use_mdp == 1) {
 257                 pr_err("%s is not allowed for a %s container. Consider /dev/md%d.\n", dev, name, num);
 258                 return -1;
 259         }
 260         if (name && trustworthy == METADATA)
 261                 use_mdp = 0;
 262         if (use_mdp == -1) {
 263                 if (autof == 4 || autof == 6)
 264                         use_mdp = 1;
 265                 else
 266                         use_mdp = 0;
 267         }
 268         if (num < 0 && trustworthy == LOCAL && name) {
 269                 /* if name is numeric, possibly prefixed by
 270                  * 'md' or '/dev/md', use that for num
 271                  * if it is not already in use */
 272                 char *ep;
 273                 char *n2 = name;
 274                 if (strncmp(n2, "/dev/", 5) == 0)
 275                         n2 += 5;
 276                 if (strncmp(n2, "md", 2) == 0)
 277                         n2 += 2;
 278                 if (*n2 == '/')
 279                         n2++;
 280                 num = strtoul(n2, &ep, 10);
 281                 if (ep == n2 || *ep)
 282                         num = -1;
 283                 else {
 284                         sprintf(devnm, "md%s%d", use_mdp ? "_d":"", num);
 285                         if (mddev_busy(devnm))
 286                                 num = -1;
 287                 }
 288         }
 289
 290         if (cname[0] == 0 && name) {
 291                 /* Need to find a name if we can
 292                  * We don't completely trust 'name'.  Truncate to
 293                  * reasonable length and remove '/'
 294                  */
 295                 char *cp;
 296                 struct map_ent *map = NULL;
 297                 int conflict = 1;
 298                 int unum = 0;
 299                 int cnlen;
 300                 strncpy(cname, name, 200);
 301                 cname[200] = 0;
 302                 for (cp = cname; *cp ; cp++)
 303                         switch (*cp) {
 304                         case '/':
 305                                 *cp = '-';
 306                                 break;
 307                         case ' ':
 308                         case '\t':
 309                                 *cp = '_';
 310                                 break;
 311                         }
 312
 313                 if (trustworthy == LOCAL ||
 314                     (trustworthy == FOREIGN && strchr(cname, ':') != NULL)) {
 315                         /* Only need suffix if there is a conflict */
 316                         if (map_by_name(&map, cname) == NULL)
 317                                 conflict = 0;
 318                 }
 319                 cnlen = strlen(cname);
 320                 while (conflict) {
 321                         if (trustworthy == METADATA && !isdigit(cname[cnlen-1]))
 322                                 sprintf(cname+cnlen, "%d", unum);
 323                         else
 324                                 /* add _%d to FOREIGN array that don't
 325                                  * a 'host:' prefix
 326                                  */
 327                                 sprintf(cname+cnlen, "_%d", unum);
 328                         unum++;
 329                         if (map_by_name(&map, cname) == NULL)
 330                                 conflict = 0;
 331                 }
 332         }
 333
 334         devnm[0] = 0;
 335         if (num < 0 && cname && ci->names) {
 336                 sprintf(devnm, "md_%s", cname);
 337                 if (block_udev)
 338                         udev_block(devnm);
 339                 if (!create_named_array(devnm)) {
 340                         devnm[0] = 0;
 341                         udev_unblock();
 342                 }
 343         }
 344         if (num >= 0) {
 345                 sprintf(devnm, "md%d", num);
 346                 if (block_udev)
 347                         udev_block(devnm);
 348                 if (!create_named_array(devnm)) {
 349                         devnm[0] = 0;
 350                         udev_unblock();
 351                 }
 352         }
 353         if (devnm[0] == 0) {
 354                 if (num < 0) {
 355                         /* need to choose a free number. */
 356                         char *_devnm = find_free_devnm(use_mdp);
 357                         if (_devnm == NULL) {
 358                                 pr_err("No avail md devices - aborting\n");
 359                                 return -1;
 360                         }
 361                         strcpy(devnm, _devnm);
 362                 } else {
 363                         sprintf(devnm, "%s%d", use_mdp?"md_d":"md", num);
 364                         if (mddev_busy(devnm)) {
 365                                 pr_err("%s is already in use.\n",
 366                                        dev);
 367                                 return -1;
 368                         }
 369                 }
 370                 if (block_udev)
 371                         udev_block(devnm);
 372         }
 373
 374         sprintf(devname, "/dev/%s", devnm);
 375
 376         if (dev && dev[0] == '/')
 377                 strcpy(chosen, dev);
 378         else if (cname[0] == 0)
 379                 strcpy(chosen, devname);
 380
 381         /* We have a device number and name.
 382          * If we cannot detect udev, we need to make
 383          * devices and links ourselves.
 384          */
 385         if (!use_udev()) {
 386                 /* Make sure 'devname' exists and 'chosen' is a symlink to it */
 387                 if (lstat(devname, &stb) == 0) {
 388                         /* Must be the correct device, else error */
 389                         if ((stb.st_mode&S_IFMT) != S_IFBLK ||
 390                             stb.st_rdev != devnm2devid(devnm)) {
 391                                 pr_err("%s exists but looks wrong, please fix\n",
 392                                         devname);
 393                                 return -1;
 394                         }
 395                 } else {
 396                         if (mknod(devname, S_IFBLK|0600,
 397                                   devnm2devid(devnm)) != 0) {
 398                                 pr_err("failed to create %s\n",
 399                                         devname);
 400                                 return -1;
 401                         }
 402                         if (chown(devname, ci->uid, ci->gid))
 403                                 perror("chown");
 404                         if (chmod(devname, ci->mode))
 405                                 perror("chmod");
 406                         stat(devname, &stb);
 407                         add_dev(devname, &stb, 0, NULL);
 408                 }
 409                 if (use_mdp == 1)
 410                         make_parts(devname, parts);
 411
 412                 if (strcmp(chosen, devname) != 0) {
 413                         if (mkdir("/dev/md",0700) == 0) {
 414                                 if (chown("/dev/md", ci->uid, ci->gid))
 415                                         perror("chown /dev/md");
 416                                 if (chmod("/dev/md", ci->mode| ((ci->mode>>2) & 0111)))
 417                                         perror("chmod /dev/md");
 418                         }
 419
 420                         if (dev && strcmp(chosen, dev) == 0)
 421                                 /* We know we are allowed to use this name */
 422                                 unlink(chosen);
 423
 424                         if (lstat(chosen, &stb) == 0) {
 425                                 char buf[300];
 426                                 ssize_t link_len = readlink(chosen, buf, sizeof(buf)-1);
 427                                 if (link_len >= 0)
 428                                         buf[link_len] = '\0';
 429
 430                                 if ((stb.st_mode & S_IFMT) != S_IFLNK ||
 431                                     link_len < 0 ||
 432                                     strcmp(buf, devname) != 0) {
 433                                         pr_err("%s exists - ignoring\n",
 434                                                 chosen);
 435                                         strcpy(chosen, devname);
 436                                 }
 437                         } else if (symlink(devname, chosen) != 0)
 438                                 pr_err("failed to create %s: %s\n",
 439                                         chosen, strerror(errno));
 440                         if (use_mdp && strcmp(chosen, devname) != 0)
 441                                 make_parts(chosen, parts);
 442                 }
 443         }
 444         mdfd = open_dev_excl(devnm);
 445         if (mdfd < 0)
 446                 pr_err("unexpected failure opening %s\n",
 447                         devname);
 448         return mdfd;
 449 }
 450
 451 /* Open this and check that it is an md device.
 452  * On success, return filedescriptor.
 453  * On failure, return -1 if it doesn't exist,
 454  * or -2 if it exists but is not an md device.
 455  */
 456 int open_mddev(char *dev, int report_errors)
 457 {
 458         int mdfd = open(dev, O_RDONLY);
 459
 460         if (mdfd < 0) {
 461                 if (report_errors)
 462                         pr_err("error opening %s: %s\n",
 463                                 dev, strerror(errno));
 464                 return -1;
 465         }
 466
 467         if (md_array_valid(mdfd) == 0) {
 468                 close(mdfd);
 469                 if (report_errors)
 470                         pr_err("%s does not appear to be an md device\n", dev);
 471                 return -2;
 472         }
 473
 474         return mdfd;
 475 }
 476
 477 char *find_free_devnm(int use_partitions)
 478 {
 479         static char devnm[32];
 480         int devnum;
 481         for (devnum = 127; devnum != 128;
 482              devnum = devnum ? devnum-1 : (1<<9)-1) {
 483
 484                 if (use_partitions)
 485                         sprintf(devnm, "md_d%d", devnum);
 486                 else
 487                         sprintf(devnm, "md%d", devnum);
 488                 if (mddev_busy(devnm))
 489                         continue;
 490                 if (!conf_name_is_free(devnm))
 491                         continue;
 492                 if (!use_udev()) {
 493                         /* make sure it is new to /dev too, at least as a
 494                          * non-standard */
 495                         dev_t devid = devnm2devid(devnm);
 496                         if (devid) {
 497                                 char *dn = map_dev(major(devid),
 498                                                    minor(devid), 0);
 499                                 if (dn && ! is_standard(dn, NULL))
 500                                         continue;
 501                         }
 502                 }
 503                 break;
 504         }
 505         if (devnum == 128)
 506                 return NULL;
 507         return devnm;
 508 }