mdopen.c

   1 /*
   2  * mdadm - manage Linux "md" devices aka RAID arrays.
   3  *
   4  * Copyright (C) 2001-2012 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 /*
 104  * We need a new md device to assemble/build/create an array.
 105  * 'dev' is a name given us by the user (command line or mdadm.conf)
 106  * It might start with /dev or /dev/md any might end with a digit
 107  * string.
 108  * If it starts with just /dev, it must be /dev/mdX or /dev/md_dX
 109  * If it ends with a digit string, then it must be as above, or
 110  * 'trustworthy' must be 'METADATA' and the 'dev' must be
 111  *  /dev/md/'name'NN or 'name'NN
 112  * If it doesn't end with a digit string, it must be /dev/md/'name'
 113  * or 'name' or must be NULL.
 114  * If the digit string is present, it gives the minor number to use
 115  * If not, we choose a high, unused minor number.
 116  * If the 'dev' is a standard name, it devices whether 'md' or 'mdp'.
 117  * else if the name is 'd[0-9]+' then we use mdp
 118  * else if trustworthy is 'METADATA' we use md
 119  * else the choice depends on 'autof'.
 120  * If name is NULL it is assumed to match whatever dev provides.
 121  * If both name and dev are NULL, we choose a name 'mdXX' or 'mdpXX'
 122  *
 123  * If 'name' is given, and 'trustworthy' is 'foreign' and name is not
 124  * supported by 'dev', we add a "_%d" suffix based on the minor number
 125  * use that.
 126  *
 127  * If udev is configured, we create a temporary device, open it, and
 128  * unlink it.
 129  * If not, we create the /dev/mdXX device, and is name is usable,
 130  * /dev/md/name
 131  * In any case we return /dev/md/name or (if that isn't available)
 132  * /dev/mdXX in 'chosen'.
 133  *
 134  * When we create devices, we use uid/gid/umask from config file.
 135  */
 136
 137 int create_mddev(char *dev, char *name, int autof, int trustworthy,
 138                  char *chosen)
 139 {
 140         int mdfd;
 141         struct stat stb;
 142         int num = -1;
 143         int use_mdp = -1;
 144         struct createinfo *ci = conf_get_create_info();
 145         int parts;
 146         char *cname;
 147         char devname[20];
 148         char cbuf[400];
 149         if (chosen == NULL)
 150                 chosen = cbuf;
 151
 152         if (autof == 0)
 153                 autof = ci->autof;
 154
 155         parts = autof >> 3;
 156         autof &= 7;
 157
 158         strcpy(chosen, "/dev/md/");
 159         cname = chosen + strlen(chosen);
 160
 161         if (dev) {
 162                 if (strncmp(dev, "/dev/md/", 8) == 0) {
 163                         strcpy(cname, dev+8);
 164                 } else if (strncmp(dev, "/dev/", 5) == 0) {
 165                         char *e = dev + strlen(dev);
 166                         while (e > dev && isdigit(e[-1]))
 167                                 e--;
 168                         if (e[0])
 169                                 num = strtoul(e, NULL, 10);
 170                         strcpy(cname, dev+5);
 171                         cname[e-(dev+5)] = 0;
 172                         /* name *must* be mdXX or md_dXX in this context */
 173                         if (num < 0 ||
 174                             (strcmp(cname, "md") != 0 && strcmp(cname, "md_d") != 0)) {
 175                                 pr_err("%s is an invalid name "
 176                                         "for an md device.  Try /dev/md/%s\n",
 177                                         dev, dev+5);
 178                                 return -1;
 179                         }
 180                         if (strcmp(cname, "md") == 0)
 181                                 use_mdp = 0;
 182                         else
 183                                 use_mdp = 1;
 184                         /* recreate name: /dev/md/0 or /dev/md/d0 */
 185                         sprintf(cname, "%s%d", use_mdp?"d":"", num);
 186                 } else
 187                         strcpy(cname, dev);
 188
 189                 /* 'cname' must not contain a slash, and may not be
 190                  * empty.
 191                  */
 192                 if (strchr(cname, '/') != NULL) {
 193                         pr_err("%s is an invalid name "
 194                                 "for an md device.\n", dev);
 195                         return -1;
 196                 }
 197                 if (cname[0] == 0) {
 198                         pr_err("%s is an invalid name "
 199                                 "for an md device (empty!).", dev);
 200                         return -1;
 201                 }
 202                 if (num < 0) {
 203                         /* If cname  is 'N' or 'dN', we get dev number
 204                          * from there.
 205                          */
 206                         char *sp = cname;
 207                         char *ep;
 208                         if (cname[0] == 'd')
 209                                 sp++;
 210                         if (isdigit(sp[0]))
 211                                 num = strtoul(sp, &ep, 10);
 212                         else
 213                                 ep = sp;
 214                         if (ep == sp || *ep || num < 0)
 215                                 num = -1;
 216                         else if (cname[0] == 'd')
 217                                 use_mdp = 1;
 218                         else
 219                                 use_mdp = 0;
 220                 }
 221         }
 222
 223         /* Now determine device number */
 224         /* named 'METADATA' cannot use 'mdp'. */
 225         if (name && name[0] == 0)
 226                 name = NULL;
 227         if (name && trustworthy == METADATA && use_mdp == 1) {
 228                 pr_err("%s is not allowed for a %s container. "
 229                         "Consider /dev/md%d.\n", dev, name, num);
 230                 return -1;
 231         }
 232         if (name && trustworthy == METADATA)
 233                 use_mdp = 0;
 234         if (use_mdp == -1) {
 235                 if (autof == 4 || autof == 6)
 236                         use_mdp = 1;
 237                 else
 238                         use_mdp = 0;
 239         }
 240         if (num < 0 && trustworthy == LOCAL && name) {
 241                 /* if name is numeric, possibly prefixed by
 242                  * 'md' or '/dev/md', use that for num
 243                  * if it is not already in use */
 244                 char *ep;
 245                 char *n2 = name;
 246                 if (strncmp(n2, "/dev/", 5) == 0)
 247                         n2 += 5;
 248                 if (strncmp(n2, "md", 2) == 0)
 249                         n2 += 2;
 250                 if (*n2 == '/')
 251                         n2++;
 252                 num = strtoul(n2, &ep, 10);
 253                 if (ep == n2 || *ep)
 254                         num = -1;
 255                 else if (mddev_busy(use_mdp ? (-1-num) : num))
 256                         num = -1;
 257         }
 258
 259         if (num < 0) {
 260                 /* need to choose a free number. */
 261                 num = find_free_devnum(use_mdp);
 262                 if (num == NoMdDev) {
 263                         pr_err("No avail md devices - aborting\n");
 264                         return -1;
 265                 }
 266         } else {
 267                 num = use_mdp ? (-1-num) : num;
 268                 if (mddev_busy(num)) {
 269                         pr_err("%s is already in use.\n",
 270                                 dev);
 271                         return -1;
 272                 }
 273         }
 274
 275         if (num < 0)
 276                 sprintf(devname, "/dev/md_d%d", -1-num);
 277         else
 278                 sprintf(devname, "/dev/md%d", num);
 279
 280         if (cname[0] == 0 && name) {
 281                 /* Need to find a name if we can
 282                  * We don't completely trust 'name'.  Truncate to
 283                  * reasonable length and remove '/'
 284                  */
 285                 char *cp;
 286                 struct map_ent *map = NULL;
 287                 int conflict = 1;
 288                 int unum = 0;
 289                 int cnlen;
 290                 strncpy(cname, name, 200);
 291                 cname[200] = 0;
 292                 for (cp = cname; *cp ; cp++)
 293                         switch (*cp) {
 294                         case '/':
 295                                 *cp = '-';
 296                                 break;
 297                         case ' ':
 298                         case '\t':
 299                                 *cp = '_';
 300                                 break;
 301                         }
 302
 303                 if (trustworthy == LOCAL ||
 304                     (trustworthy == FOREIGN && strchr(cname, ':') != NULL)) {
 305                         /* Only need suffix if there is a conflict */
 306                         if (map_by_name(&map, cname) == NULL)
 307                                 conflict = 0;
 308                 }
 309                 cnlen = strlen(cname);
 310                 while (conflict) {
 311                         if (trustworthy == METADATA && !isdigit(cname[cnlen-1]))
 312                                 sprintf(cname+cnlen, "%d", unum);
 313                         else
 314                                 /* add _%d to FOREIGN array that don't
 315                                  * a 'host:' prefix
 316                                  */
 317                                 sprintf(cname+cnlen, "_%d", unum);
 318                         unum++;
 319                         if (map_by_name(&map, cname) == NULL)
 320                                 conflict = 0;
 321                 }
 322         }
 323
 324         if (dev && dev[0] == '/')
 325                 strcpy(chosen, dev);
 326         else if (cname[0] == 0)
 327                 strcpy(chosen, devname);
 328
 329         /* We have a device number and name.
 330          * If we cannot detect udev, we need to make
 331          * devices and links ourselves.
 332          */
 333         if (!use_udev()) {
 334                 /* Make sure 'devname' exists and 'chosen' is a symlink to it */
 335                 if (lstat(devname, &stb) == 0) {
 336                         /* Must be the correct device, else error */
 337                         if ((stb.st_mode&S_IFMT) != S_IFBLK ||
 338                             stb.st_rdev != makedev(dev2major(num),dev2minor(num))) {
 339                                 pr_err("%s exists but looks wrong, please fix\n",
 340                                         devname);
 341                                 return -1;
 342                         }
 343                 } else {
 344                         if (mknod(devname, S_IFBLK|0600,
 345                                   makedev(dev2major(num),dev2minor(num))) != 0) {
 346                                 pr_err("failed to create %s\n",
 347                                         devname);
 348                                 return -1;
 349                         }
 350                         if (chown(devname, ci->uid, ci->gid))
 351                                 perror("chown");
 352                         if (chmod(devname, ci->mode))
 353                                 perror("chmod");
 354                         stat(devname, &stb);
 355                         add_dev(devname, &stb, 0, NULL);
 356                 }
 357                 if (use_mdp == 1)
 358                         make_parts(devname, parts);
 359
 360                 if (strcmp(chosen, devname) != 0) {
 361                         if (mkdir("/dev/md",0700) == 0) {
 362                                 if (chown("/dev/md", ci->uid, ci->gid))
 363                                         perror("chown /dev/md");
 364                                 if (chmod("/dev/md", ci->mode| ((ci->mode>>2) & 0111)))
 365                                         perror("chmod /dev/md");
 366                         }
 367
 368                         if (dev && strcmp(chosen, dev) == 0)
 369                                 /* We know we are allowed to use this name */
 370                                 unlink(chosen);
 371
 372                         if (lstat(chosen, &stb) == 0) {
 373                                 char buf[300];
 374                                 ssize_t link_len = readlink(chosen, buf, sizeof(buf)-1);
 375                                 if (link_len >= 0)
 376                                         buf[link_len] = '\0';
 377
 378                                 if ((stb.st_mode & S_IFMT) != S_IFLNK ||
 379                                     link_len < 0 ||
 380                                     strcmp(buf, devname) != 0) {
 381                                         pr_err("%s exists - ignoring\n",
 382                                                 chosen);
 383                                         strcpy(chosen, devname);
 384                                 }
 385                         } else if (symlink(devname, chosen) != 0)
 386                                 pr_err("failed to create %s: %s\n",
 387                                         chosen, strerror(errno));
 388                         if (use_mdp && strcmp(chosen, devname) != 0)
 389                                 make_parts(chosen, parts);
 390                 }
 391         }
 392         mdfd = open_dev_excl(num);
 393         if (mdfd < 0)
 394                 pr_err("unexpected failure opening %s\n",
 395                         devname);
 396         return mdfd;
 397 }
 398
 399 /* Open this and check that it is an md device.
 400  * On success, return filedescriptor.
 401  * On failure, return -1 if it doesn't exist,
 402  * or -2 if it exists but is not an md device.
 403  */
 404 int open_mddev(char *dev, int report_errors)
 405 {
 406         int mdfd = open(dev, O_RDWR);
 407         if (mdfd < 0 && errno == EACCES)
 408                 mdfd = open(dev, O_RDONLY);
 409         if (mdfd < 0) {
 410                 if (report_errors)
 411                         pr_err("error opening %s: %s\n",
 412                                 dev, strerror(errno));
 413                 return -1;
 414         }
 415         if (md_get_version(mdfd) <= 0) {
 416                 close(mdfd);
 417                 if (report_errors)
 418                         pr_err("%s does not appear to be "
 419                                 "an md device\n", dev);
 420                 return -2;
 421         }
 422         return mdfd;
 423 }