mdopen.c

   1 /*
   2  * mdadm - manage Linux "md" devices aka RAID arrays.
   3  *
   4  * Copyright (C) 2001-2009 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
  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 = major_num; /* quiet gcc -Os unitialized warning */
  42         int minor_num = minor_num; /* quiet gcc -Os unitialized warning */
  43         int odig = odig; /* quiet gcc -Os unitialized warning */
  44         int i;
  45         int nlen = strlen(dev) + 20;
  46         char *name = malloc(nlen);
  47         int dig = isdigit(dev[strlen(dev)-1]);
  48         char orig[1024];
  49         char sym[1024];
  50         int err;
  51
  52         if (cnt==0) cnt=4;
  53         if (lstat(dev, &stb)!= 0)
  54                 return;
  55         if (S_ISLNK(stb.st_mode)) {
  56                 int len = readlink(dev, orig, sizeof(orig));
  57                 if (len < 0 || len > 1000)
  58                         return;
  59                 orig[len] = 0;
  60                 odig = isdigit(orig[len-1]);
  61         } else if (S_ISBLK(stb.st_mode)) {
  62                 major_num = major(stb.st_rdev);
  63                 minor_num = minor(stb.st_rdev);
  64         } else
  65                    return;
  66         for (i=1; i <= cnt ; i++) {
  67                 struct stat stb2;
  68                 snprintf(name, nlen, "%s%s%d", dev, dig?"p":"", i);
  69                 if (stat(name, &stb2)==0) {
  70                         if (!S_ISBLK(stb2.st_mode))
  71                                 continue;
  72                         if (stb2.st_rdev == makedev(major_num, minor_num+i))
  73                                 continue;
  74                         unlink(name);
  75                 } else {
  76                         stb2 = stb;
  77                 }
  78                 if (S_ISBLK(stb.st_mode)) {
  79                         if (mknod(name, S_IFBLK | 0600,
  80                                   makedev(major_num, minor_num+i)))
  81                                 perror("mknod");
  82                         if (chown(name, stb2.st_uid, stb2.st_gid))
  83                                 perror("chown");
  84                         if (chmod(name, stb2.st_mode & 07777))
  85                                 perror("chmod");
  86                         err = 0;
  87                 } else {
  88                         snprintf(sym, sizeof(sym), "%s%s%d", orig, odig?"p":"", i);
  89                         err = symlink(sym, name);
  90                 }
  91
  92                 if (err == 0 && stat(name, &stb2) == 0)
  93                         add_dev(name, &stb2, 0, NULL);
  94         }
  95 }
  96
  97
  98 /*
  99  * We need a new md device to assemble/build/create an array.
 100  * 'dev' is a name given us by the user (command line or mdadm.conf)
 101  * It might start with /dev or /dev/md any might end with a digit
 102  * string.
 103  * If it starts with just /dev, it must be /dev/mdX or /dev/md_dX
 104  * If it ends with a digit string, then it must be as above, or
 105  * 'trustworthy' must be 'METADATA' and the 'dev' must be
 106  *  /dev/md/'name'NN or 'name'NN
 107  * If it doesn't end with a digit string, it must be /dev/md/'name'
 108  * or 'name' or must be NULL.
 109  * If the digit string is present, it gives the minor number to use
 110  * If not, we choose a high, unused minor number.
 111  * If the 'dev' is a standard name, it devices whether 'md' or 'mdp'.
 112  * else if the name is 'd[0-9]+' then we use mdp
 113  * else if trustworthy is 'METADATA' we use md
 114  * else the choice depends on 'autof'.
 115  * If name is NULL it is assumed to match whatever dev provides.
 116  * If both name and dev are NULL, we choose a name 'mdXX' or 'mdpXX'
 117  *
 118  * If 'name' is given, and 'trustworthy' is 'foreign' and name is not
 119  * supported by 'dev', we add a "_%d" suffix based on the minor number
 120  * use that.
 121  *
 122  * If udev is configured, we create a temporary device, open it, and
 123  * unlink it.
 124  * If not, we create the /dev/mdXX device, and is name is usable,
 125  * /dev/md/name
 126  * In any case we return /dev/md/name or (if that isn't available)
 127  * /dev/mdXX in 'chosen'.
 128  *
 129  * When we create devices, we use uid/gid/umask from config file.
 130  */
 131
 132 int create_mddev(char *dev, char *name, int autof, int trustworthy,
 133                  char *chosen)
 134 {
 135         int mdfd;
 136         struct stat stb;
 137         int num = -1;
 138         int use_mdp = -1;
 139         struct createinfo *ci = conf_get_create_info();
 140         int parts;
 141         char *cname;
 142         char devname[20];
 143         char cbuf[400];
 144         if (chosen == NULL)
 145                 chosen = cbuf;
 146
 147
 148         if (autof == 0)
 149                 autof = ci->autof;
 150
 151         parts = autof >> 3;
 152         autof &= 7;
 153
 154         strcpy(chosen, "/dev/md/");
 155         cname = chosen + strlen(chosen);
 156
 157
 158         if (dev) {
 159                 if (strncmp(dev, "/dev/md/", 8) == 0) {
 160                         strcpy(cname, dev+8);
 161                 } else if (strncmp(dev, "/dev/", 5) == 0) {
 162                         char *e = dev + strlen(dev);
 163                         while (e > dev && isdigit(e[-1]))
 164                                 e--;
 165                         if (e[0])
 166                                 num = strtoul(e, NULL, 10);
 167                         strcpy(cname, dev+5);
 168                         cname[e-(dev+5)] = 0;
 169                         /* name *must* be mdXX or md_dXX in this context */
 170                         if (num < 0 ||
 171                             (strcmp(cname, "md") != 0 && strcmp(cname, "md_d") != 0)) {
 172                                 fprintf(stderr, Name ": %s is an invalid name "
 173                                         "for an md device.  Try /dev/md/%s\n",
 174                                         dev, dev+5);
 175                                 return -1;
 176                         }
 177                         if (strcmp(cname, "md") == 0)
 178                                 use_mdp = 0;
 179                         else
 180                                 use_mdp = 1;
 181                         /* recreate name: /dev/md/0 or /dev/md/d0 */
 182                         sprintf(cname, "%s%d", use_mdp?"d":"", num);
 183                 } else
 184                         strcpy(cname, dev);
 185
 186                 /* 'cname' must not contain a slash, and may not be
 187                  * empty.
 188                  */
 189                 if (strchr(cname, '/') != NULL) {
 190                         fprintf(stderr, Name ": %s is an invalid name "
 191                                 "for an md device.\n", dev);
 192                         return -1;
 193                 }
 194                 if (cname[0] == 0) {
 195                         fprintf(stderr, Name ": %s is an invalid name "
 196                                 "for an md device (empty!).", dev);
 197                         return -1;
 198                 }
 199                 if (num < 0) {
 200                         /* If cname  is 'N' or 'dN', we get dev number
 201                          * from there.
 202                          */
 203                         char *sp = cname;
 204                         char *ep;
 205                         if (cname[0] == 'd')
 206                                 sp++;
 207                         num = strtoul(sp, &ep, 10);
 208                         if (ep == sp || *ep || num < 0)
 209                                 num = -1;
 210                         else if (cname[0] == 'd')
 211                                 use_mdp = 1;
 212                         else
 213                                 use_mdp = 0;
 214                 }
 215         }
 216
 217         /* Now determine device number */
 218         /* named 'METADATA' cannot use 'mdp'. */
 219         if (name && name[0] == 0)
 220                 name = NULL;
 221         if (name && trustworthy == METADATA && use_mdp == 1) {
 222                 fprintf(stderr, Name ": %s is not allowed for a %s container. "
 223                         "Consider /dev/md%d.\n", dev, name, num);
 224                 return -1;
 225         }
 226         if (name && trustworthy == METADATA)
 227                 use_mdp = 0;
 228         if (use_mdp == -1) {
 229                 if (autof == 4 || autof == 6)
 230                         use_mdp = 1;
 231                 else
 232                         use_mdp = 0;
 233         }
 234         if (num < 0 && trustworthy == LOCAL && name) {
 235                 /* if name is numeric, possibly prefixed by
 236                  * 'md' or '/dev/md', use that for num
 237                  * if it is not already in use */
 238                 char *ep;
 239                 char *n2 = name;
 240                 if (strncmp(n2, "/dev/", 5) == 0)
 241                         n2 += 5;
 242                 if (strncmp(n2, "md", 2) == 0)
 243                         n2 += 2;
 244                 if (*n2 == '/')
 245                         n2++;
 246                 num = strtoul(n2, &ep, 10);
 247                 if (ep == n2 || *ep)
 248                         num = -1;
 249                 else if (mddev_busy(use_mdp ? (-1-num) : num))
 250                         num = -1;
 251         }
 252
 253         if (num < 0) {
 254                 /* need to choose a free number. */
 255                 num = find_free_devnum(use_mdp);
 256                 if (num == NoMdDev) {
 257                         fprintf(stderr, Name ": No avail md devices - aborting\n");
 258                         return -1;
 259                 }
 260         } else {
 261                 num = use_mdp ? (-1-num) : num;
 262                 if (mddev_busy(num)) {
 263                         fprintf(stderr, Name ": %s is already in use.\n",
 264                                 dev);
 265                         return -1;
 266                 }
 267         }
 268
 269         if (num < 0)
 270                 sprintf(devname, "/dev/md_d%d", -1-num);
 271         else
 272                 sprintf(devname, "/dev/md%d", num);
 273
 274         if (cname[0] == 0 && name) {
 275                 /* Need to find a name if we can
 276                  * We don't completely trust 'name'.  Truncate to
 277                  * reasonable length and remove '/'
 278                  */
 279                 char *cp;
 280                 struct map_ent *map = NULL;
 281                 int conflict = 1;
 282                 int unum = 0;
 283                 int cnlen;
 284                 strncpy(cname, name, 200);
 285                 cname[200] = 0;
 286                 while ((cp = strchr(cname, '/')) != NULL)
 287                         *cp = '-';
 288                 if (trustworthy == LOCAL ||
 289                     (trustworthy == FOREIGN && strchr(cname, ':') != NULL)) {
 290                         /* Only need suffix if there is a conflict */
 291                         if (map_by_name(&map, cname) == NULL)
 292                                 conflict = 0;
 293                 }
 294                 cnlen = strlen(cname);
 295                 while (conflict) {
 296                         if (trustworthy == METADATA && !isdigit(cname[cnlen-1]))
 297                                 sprintf(cname+cnlen, "%d", unum);
 298                         else
 299                                 /* add _%d to FOREIGN array that don't
 300                                  * a 'host:' prefix
 301                                  */
 302                                 sprintf(cname+cnlen, "_%d", unum);
 303                         unum++;
 304                         if (map_by_name(&map, cname) == NULL)
 305                                 conflict = 0;
 306                 }
 307         }
 308
 309         if (dev && dev[0] == '/')
 310                 strcpy(chosen, dev);
 311         else if (cname[0] == 0)
 312                 strcpy(chosen, devname);
 313
 314         /* We have a device number and name.
 315          * If we cannot detect udev, we need to make
 316          * devices and links ourselves.
 317          */
 318         if (stat("/dev/.udev", &stb) != 0 ||
 319             check_env("MDADM_NO_UDEV")) {
 320                 /* Make sure 'devname' exists and 'chosen' is a symlink to it */
 321                 if (lstat(devname, &stb) == 0) {
 322                         /* Must be the correct device, else error */
 323                         if ((stb.st_mode&S_IFMT) != S_IFBLK ||
 324                             stb.st_rdev != makedev(dev2major(num),dev2minor(num))) {
 325                                 fprintf(stderr, Name ": %s exists but looks wrong, please fix\n",
 326                                         devname);
 327                                 return -1;
 328                         }
 329                 } else {
 330                         if (mknod(devname, S_IFBLK|0600,
 331                                   makedev(dev2major(num),dev2minor(num))) != 0) {
 332                                 fprintf(stderr, Name ": failed to create %s\n",
 333                                         devname);
 334                                 return -1;
 335                         }
 336                         if (chown(devname, ci->uid, ci->gid))
 337                                 perror("chown");
 338                         if (chmod(devname, ci->mode))
 339                                 perror("chmod");
 340                         stat(devname, &stb);
 341                         add_dev(devname, &stb, 0, NULL);
 342                 }
 343                 if (use_mdp == 1)
 344                         make_parts(devname, parts);
 345                 if (strcmp(chosen, devname) != 0) {
 346
 347                         if (mkdir("/dev/md",0700)==0) {
 348                                 if (chown("/dev/md", ci->uid, ci->gid))
 349                                         perror("chown /dev/md");
 350                                 if (chmod("/dev/md", ci->mode| ((ci->mode>>2) & 0111)))
 351                                         perror("chmod /dev/md");
 352                         }
 353
 354                         if (dev && strcmp(chosen, dev) == 0)
 355                                 /* We know we are allowed to use this name */
 356                                 unlink(chosen);
 357
 358                         if (lstat(chosen, &stb) == 0) {
 359                                 char buf[300];
 360                                 if ((stb.st_mode & S_IFMT) != S_IFLNK ||
 361                                     readlink(chosen, buf, 300) <0 ||
 362                                     strcmp(buf, devname) != 0) {
 363                                         fprintf(stderr, Name ": %s exists - ignoring\n",
 364                                                 chosen);
 365                                         strcpy(chosen, devname);
 366                                 }
 367                         } else if (symlink(devname, chosen) != 0)
 368                                 fprintf(stderr, Name ": failed to create %s: %s\n",
 369                                         chosen, strerror(errno));
 370                         if (use_mdp && strcmp(chosen, devname) != 0)
 371                                 make_parts(chosen, parts);
 372                 }
 373         }
 374         mdfd = open_dev_excl(num);
 375         if (mdfd < 0)
 376                 fprintf(stderr, Name ": unexpected failure opening %s\n",
 377                         devname);
 378         return mdfd;
 379 }
 380
 381
 382 /* Open this and check that it is an md device.
 383  * On success, return filedescriptor.
 384  * On failure, return -1 if it doesn't exist,
 385  * or -2 if it exists but is not an md device.
 386  */
 387 int open_mddev(char *dev, int report_errors)
 388 {
 389         int mdfd = open(dev, O_RDWR);
 390         if (mdfd < 0) {
 391                 if (report_errors)
 392                         fprintf(stderr, Name ": error opening %s: %s\n",
 393                                 dev, strerror(errno));
 394                 return -1;
 395         }
 396         if (md_get_version(mdfd) <= 0) {
 397                 close(mdfd);
 398                 if (report_errors)
 399                         fprintf(stderr, Name ": %s does not appear to be "
 400                                 "an md device\n", dev);
 401                 return -2;
 402         }
 403         return mdfd;
 404 }