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[1024];
  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 = readlink(dev, orig, sizeof(orig));
  62                 if (len < 0 || len > 1000)
  63                         return;
  64                 orig[len] = 0;
  65                 odig = isdigit(orig[len-1]);
  66                 major_num = -1;
  67                 minor_num = -1;
  68         } else
  69                 return;
  70         name = xmalloc(nlen);
  71         for (i = 1; i <= cnt ; i++) {
  72                 struct stat stb2;
  73                 snprintf(name, nlen, "%s%s%d", dev, dig?"p":"", i);
  74                 if (stat(name, &stb2) == 0) {
  75                         if (!S_ISBLK(stb2.st_mode) || !S_ISBLK(stb.st_mode))
  76                                 continue;
  77                         if (stb2.st_rdev == makedev(major_num, minor_num+i))
  78                                 continue;
  79                         unlink(name);
  80                 } else {
  81                         stb2 = stb;
  82                 }
  83                 if (S_ISBLK(stb.st_mode)) {
  84                         if (mknod(name, S_IFBLK | 0600,
  85                                   makedev(major_num, minor_num+i)))
  86                                 perror("mknod");
  87                         if (chown(name, stb2.st_uid, stb2.st_gid))
  88                                 perror("chown");
  89                         if (chmod(name, stb2.st_mode & 07777))
  90                                 perror("chmod");
  91                         err = 0;
  92                 } else {
  93                         snprintf(sym, sizeof(sym), "%s%s%d", orig, odig?"p":"", i);
  94                         err = symlink(sym, name);
  95                 }
  96
  97                 if (err == 0 && stat(name, &stb2) == 0)
  98                         add_dev(name, &stb2, 0, NULL);
  99         }
 100         free(name);
 101 }
 102
 103 int create_named_array(char *devnm)
 104 {
 105         int fd;
 106         int n = -1;
 107         static const char new_array_file[] = {
 108                 "/sys/module/md_mod/parameters/new_array"
 109         };
 110
 111         fd = open(new_array_file, O_WRONLY);
 112         if (fd < 0 && errno == ENOENT) {
 113                 if (system("modprobe md_mod") == 0)
 114                         fd = open(new_array_file, O_WRONLY);
 115         }
 116         if (fd >= 0) {
 117                 n = write(fd, devnm, strlen(devnm));
 118                 close(fd);
 119         }
 120         if (fd < 0 || n != (int)strlen(devnm)) {
 121                 pr_err("Fail create %s when using %s\n", devnm, new_array_file);
 122                 return 0;
 123         }
 124
 125         return 1;
 126 }
 127
 128 /*
 129  * We need a new md device to assemble/build/create an array.
 130  * 'dev' is a name given us by the user (command line or mdadm.conf)
 131  * It might start with /dev or /dev/md any might end with a digit
 132  * string.
 133  * If it starts with just /dev, it must be /dev/mdX or /dev/md_dX
 134  * If it ends with a digit string, then it must be as above, or
 135  * 'trustworthy' must be 'METADATA' and the 'dev' must be
 136  *  /dev/md/'name'NN or 'name'NN
 137  * If it doesn't end with a digit string, it must be /dev/md/'name'
 138  * or 'name' or must be NULL.
 139  * If the digit string is present, it gives the minor number to use
 140  * If not, we choose a high, unused minor number.
 141  * If the 'dev' is a standard name, it devices whether 'md' or 'mdp'.
 142  * else if the name is 'd[0-9]+' then we use mdp
 143  * else if trustworthy is 'METADATA' we use md
 144  * else the choice depends on 'autof'.
 145  * If name is NULL it is assumed to match whatever dev provides.
 146  * If both name and dev are NULL, we choose a name 'mdXX' or 'mdpXX'
 147  *
 148  * If 'name' is given, and 'trustworthy' is 'foreign' and name is not
 149  * supported by 'dev', we add a "_%d" suffix based on the minor number
 150  * use that.
 151  *
 152  * If udev is configured, we create a temporary device, open it, and
 153  * unlink it.
 154  * If not, we create the /dev/mdXX device, and if name is usable,
 155  * /dev/md/name
 156  * In any case we return /dev/md/name or (if that isn't available)
 157  * /dev/mdXX in 'chosen'.
 158  *
 159  * When we create devices, we use uid/gid/umask from config file.
 160  */
 161
 162 int create_mddev(char *dev, char *name, int autof, int trustworthy,
 163                  char *chosen, int block_udev)
 164 {
 165         int mdfd;
 166         struct stat stb;
 167         int num = -1;
 168         int use_mdp = -1;
 169         struct createinfo *ci = conf_get_create_info();
 170         int parts;
 171         char *cname;
 172         char devname[37];
 173         char devnm[32];
 174         char cbuf[400];
 175
 176         if (!use_udev())
 177                 block_udev = 0;
 178
 179         if (chosen == NULL)
 180                 chosen = cbuf;
 181
 182         if (autof == 0)
 183                 autof = ci->autof;
 184
 185         parts = autof >> 3;
 186         autof &= 7;
 187
 188         strcpy(chosen, "/dev/md/");
 189         cname = chosen + strlen(chosen);
 190
 191         if (dev) {
 192                 if (strncmp(dev, "/dev/md/", 8) == 0) {
 193                         strcpy(cname, dev+8);
 194                 } else if (strncmp(dev, "/dev/", 5) == 0) {
 195                         char *e = dev + strlen(dev);
 196                         while (e > dev && isdigit(e[-1]))
 197                                 e--;
 198                         if (e[0])
 199                                 num = strtoul(e, NULL, 10);
 200                         strcpy(cname, dev+5);
 201                         cname[e-(dev+5)] = 0;
 202                         /* name *must* be mdXX or md_dXX in this context */
 203                         if (num < 0 ||
 204                             (strcmp(cname, "md") != 0 && strcmp(cname, "md_d") != 0)) {
 205                                 pr_err("%s is an invalid name for an md device.  Try /dev/md/%s\n",
 206                                         dev, dev+5);
 207                                 return -1;
 208                         }
 209                         if (strcmp(cname, "md") == 0)
 210                                 use_mdp = 0;
 211                         else
 212                                 use_mdp = 1;
 213                         /* recreate name: /dev/md/0 or /dev/md/d0 */
 214                         sprintf(cname, "%s%d", use_mdp?"d":"", num);
 215                 } else
 216                         strcpy(cname, dev);
 217
 218                 /* 'cname' must not contain a slash, and may not be
 219                  * empty.
 220                  */
 221                 if (strchr(cname, '/') != NULL) {
 222                         pr_err("%s is an invalid name for an md device.\n", dev);
 223                         return -1;
 224                 }
 225                 if (cname[0] == 0) {
 226                         pr_err("%s is an invalid name for an md device (empty!).\n", dev);
 227                         return -1;
 228                 }
 229                 if (num < 0) {
 230                         /* If cname  is 'N' or 'dN', we get dev number
 231                          * from there.
 232                          */
 233                         char *sp = cname;
 234                         char *ep;
 235                         if (cname[0] == 'd')
 236                                 sp++;
 237                         if (isdigit(sp[0]))
 238                                 num = strtoul(sp, &ep, 10);
 239                         else
 240                                 ep = sp;
 241                         if (ep == sp || *ep || num < 0)
 242                                 num = -1;
 243                         else if (cname[0] == 'd')
 244                                 use_mdp = 1;
 245                         else
 246                                 use_mdp = 0;
 247                 }
 248         }
 249
 250         /* Now determine device number */
 251         /* named 'METADATA' cannot use 'mdp'. */
 252         if (name && name[0] == 0)
 253                 name = NULL;
 254         if (name && trustworthy == METADATA && use_mdp == 1) {
 255                 pr_err("%s is not allowed for a %s container. Consider /dev/md%d.\n", dev, name, num);
 256                 return -1;
 257         }
 258         if (name && trustworthy == METADATA)
 259                 use_mdp = 0;
 260         if (use_mdp == -1) {
 261                 if (autof == 4 || autof == 6)
 262                         use_mdp = 1;
 263                 else
 264                         use_mdp = 0;
 265         }
 266         if (num < 0 && trustworthy == LOCAL && name) {
 267                 /* if name is numeric, possibly prefixed by
 268                  * 'md' or '/dev/md', use that for num
 269                  * if it is not already in use */
 270                 char *ep;
 271                 char *n2 = name;
 272                 if (strncmp(n2, "/dev/", 5) == 0)
 273                         n2 += 5;
 274                 if (strncmp(n2, "md", 2) == 0)
 275                         n2 += 2;
 276                 if (*n2 == '/')
 277                         n2++;
 278                 num = strtoul(n2, &ep, 10);
 279                 if (ep == n2 || *ep)
 280                         num = -1;
 281                 else {
 282                         sprintf(devnm, "md%s%d", use_mdp ? "_d":"", num);
 283                         if (mddev_busy(devnm))
 284                                 num = -1;
 285                 }
 286         }
 287
 288         if (cname[0] == 0 && name) {
 289                 /* Need to find a name if we can
 290                  * We don't completely trust 'name'.  Truncate to
 291                  * reasonable length and remove '/'
 292                  */
 293                 char *cp;
 294                 struct map_ent *map = NULL;
 295                 int conflict = 1;
 296                 int unum = 0;
 297                 int cnlen;
 298                 strncpy(cname, name, 200);
 299                 cname[200] = 0;
 300                 for (cp = cname; *cp ; cp++)
 301                         switch (*cp) {
 302                         case '/':
 303                                 *cp = '-';
 304                                 break;
 305                         case ' ':
 306                         case '\t':
 307                                 *cp = '_';
 308                                 break;
 309                         }
 310
 311                 if (trustworthy == LOCAL ||
 312                     (trustworthy == FOREIGN && strchr(cname, ':') != NULL)) {
 313                         /* Only need suffix if there is a conflict */
 314                         if (map_by_name(&map, cname) == NULL)
 315                                 conflict = 0;
 316                 }
 317                 cnlen = strlen(cname);
 318                 while (conflict) {
 319                         if (trustworthy == METADATA && !isdigit(cname[cnlen-1]))
 320                                 sprintf(cname+cnlen, "%d", unum);
 321                         else
 322                                 /* add _%d to FOREIGN array that don't
 323                                  * a 'host:' prefix
 324                                  */
 325                                 sprintf(cname+cnlen, "_%d", unum);
 326                         unum++;
 327                         if (map_by_name(&map, cname) == NULL)
 328                                 conflict = 0;
 329                 }
 330         }
 331
 332         devnm[0] = 0;
 333         if (num < 0 && cname && ci->names) {
 334                 sprintf(devnm, "md_%s", cname);
 335                 if (block_udev)
 336                         udev_block(devnm);
 337                 if (!create_named_array(devnm)) {
 338                         devnm[0] = 0;
 339                         udev_unblock();
 340                 }
 341         }
 342         if (num >= 0) {
 343                 sprintf(devnm, "md%d", num);
 344                 if (block_udev)
 345                         udev_block(devnm);
 346                 if (!create_named_array(devnm)) {
 347                         devnm[0] = 0;
 348                         udev_unblock();
 349                 }
 350         }
 351         if (devnm[0] == 0) {
 352                 if (num < 0) {
 353                         /* need to choose a free number. */
 354                         char *_devnm = find_free_devnm(use_mdp);
 355                         if (_devnm == NULL) {
 356                                 pr_err("No avail md devices - aborting\n");
 357                                 return -1;
 358                         }
 359                         strcpy(devnm, _devnm);
 360                 } else {
 361                         sprintf(devnm, "%s%d", use_mdp?"md_d":"md", num);
 362                         if (mddev_busy(devnm)) {
 363                                 pr_err("%s is already in use.\n",
 364                                        dev);
 365                                 return -1;
 366                         }
 367                 }
 368                 if (block_udev)
 369                         udev_block(devnm);
 370         }
 371
 372         sprintf(devname, "/dev/%s", devnm);
 373
 374         if (dev && dev[0] == '/')
 375                 strcpy(chosen, dev);
 376         else if (cname[0] == 0)
 377                 strcpy(chosen, devname);
 378
 379         /* We have a device number and name.
 380          * If we cannot detect udev, we need to make
 381          * devices and links ourselves.
 382          */
 383         if (!use_udev()) {
 384                 /* Make sure 'devname' exists and 'chosen' is a symlink to it */
 385                 if (lstat(devname, &stb) == 0) {
 386                         /* Must be the correct device, else error */
 387                         if ((stb.st_mode&S_IFMT) != S_IFBLK ||
 388                             stb.st_rdev != devnm2devid(devnm)) {
 389                                 pr_err("%s exists but looks wrong, please fix\n",
 390                                         devname);
 391                                 return -1;
 392                         }
 393                 } else {
 394                         if (mknod(devname, S_IFBLK|0600,
 395                                   devnm2devid(devnm)) != 0) {
 396                                 pr_err("failed to create %s\n",
 397                                         devname);
 398                                 return -1;
 399                         }
 400                         if (chown(devname, ci->uid, ci->gid))
 401                                 perror("chown");
 402                         if (chmod(devname, ci->mode))
 403                                 perror("chmod");
 404                         stat(devname, &stb);
 405                         add_dev(devname, &stb, 0, NULL);
 406                 }
 407                 if (use_mdp == 1)
 408                         make_parts(devname, parts);
 409
 410                 if (strcmp(chosen, devname) != 0) {
 411                         if (mkdir("/dev/md",0700) == 0) {
 412                                 if (chown("/dev/md", ci->uid, ci->gid))
 413                                         perror("chown /dev/md");
 414                                 if (chmod("/dev/md", ci->mode| ((ci->mode>>2) & 0111)))
 415                                         perror("chmod /dev/md");
 416                         }
 417
 418                         if (dev && strcmp(chosen, dev) == 0)
 419                                 /* We know we are allowed to use this name */
 420                                 unlink(chosen);
 421
 422                         if (lstat(chosen, &stb) == 0) {
 423                                 char buf[300];
 424                                 ssize_t link_len = readlink(chosen, buf, sizeof(buf)-1);
 425                                 if (link_len >= 0)
 426                                         buf[link_len] = '\0';
 427
 428                                 if ((stb.st_mode & S_IFMT) != S_IFLNK ||
 429                                     link_len < 0 ||
 430                                     strcmp(buf, devname) != 0) {
 431                                         pr_err("%s exists - ignoring\n",
 432                                                 chosen);
 433                                         strcpy(chosen, devname);
 434                                 }
 435                         } else if (symlink(devname, chosen) != 0)
 436                                 pr_err("failed to create %s: %s\n",
 437                                         chosen, strerror(errno));
 438                         if (use_mdp && strcmp(chosen, devname) != 0)
 439                                 make_parts(chosen, parts);
 440                 }
 441         }
 442         mdfd = open_dev_excl(devnm);
 443         if (mdfd < 0)
 444                 pr_err("unexpected failure opening %s\n",
 445                         devname);
 446         return mdfd;
 447 }
 448
 449 /* Open this and check that it is an md device.
 450  * On success, return filedescriptor.
 451  * On failure, return -1 if it doesn't exist,
 452  * or -2 if it exists but is not an md device.
 453  */
 454 int open_mddev(char *dev, int report_errors)
 455 {
 456         int mdfd = open(dev, O_RDONLY);
 457
 458         if (mdfd < 0) {
 459                 if (report_errors)
 460                         pr_err("error opening %s: %s\n",
 461                                 dev, strerror(errno));
 462                 return -1;
 463         }
 464
 465         if (md_array_valid(mdfd) == 0) {
 466                 close(mdfd);
 467                 if (report_errors)
 468                         pr_err("%s does not appear to be an md device\n", dev);
 469                 return -2;
 470         }
 471
 472         return mdfd;
 473 }
 474
 475 char *find_free_devnm(int use_partitions)
 476 {
 477         static char devnm[32];
 478         int devnum;
 479         for (devnum = 127; devnum != 128;
 480              devnum = devnum ? devnum-1 : (1<<9)-1) {
 481
 482                 if (use_partitions)
 483                         sprintf(devnm, "md_d%d", devnum);
 484                 else
 485                         sprintf(devnm, "md%d", devnum);
 486                 if (mddev_busy(devnm))
 487                         continue;
 488                 if (!conf_name_is_free(devnm))
 489                         continue;
 490                 if (!use_udev()) {
 491                         /* make sure it is new to /dev too, at least as a
 492                          * non-standard */
 493                         dev_t devid = devnm2devid(devnm);
 494                         if (devid) {
 495                                 char *dn = map_dev(major(devid),
 496                                                    minor(devid), 0);
 497                                 if (dn && ! is_standard(dn, NULL))
 498                                         continue;
 499                         }
 500                 }
 501                 break;
 502         }
 503         if (devnum == 128)
 504                 return NULL;
 505         return devnm;
 506 }