mdopen.c

   1 /*
   2  * mdadm - manage Linux "md" devices aka RAID arrays.
   3  *
   4  * Copyright (C) 2001-2006 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@cse.unsw.edu.au>
  23  *    Paper: Neil Brown
  24  *           School of Computer Science and Engineering
  25  *           The University of New South Wales
  26  *           Sydney, 2052
  27  *           Australia
  28  */
  29
  30 #include "mdadm.h"
  31 #include "md_p.h"
  32 #include <ctype.h>
  33
  34
  35 void make_dev_symlink(char *dev)
  36 {
  37         char *new = strdup(dev);
  38
  39         if (!new) return;
  40         /* /dev/md/0 -> /dev/md0
  41          * /dev/md/d0 -> /dev/md_d0
  42          */
  43         if (isdigit(new[8]))
  44                 strcpy(new+7, new+8);
  45         else
  46                 new[7] = '_';
  47         if (symlink(dev+5, new))
  48                 perror(new);
  49 }
  50
  51
  52 void make_parts(char *dev, int cnt, int symlinks)
  53 {
  54         /* make 'cnt' partition devices for 'dev'
  55          * We use the major/minor from dev and add 1..cnt
  56          * If dev ends with a digit, we add "p%d" else "%d"
  57          * If the name exists, we use it's owner/mode,
  58          * else that of dev
  59          */
  60         struct stat stb;
  61         int major_num, minor_num;
  62         int i;
  63         int nlen = strlen(dev) + 20;
  64         char *name = malloc(nlen);
  65         int dig = isdigit(dev[strlen(dev)-1]);
  66
  67         if (cnt==0) cnt=4;
  68         if (stat(dev, &stb)!= 0)
  69                 return;
  70         if (!S_ISBLK(stb.st_mode))
  71                 return;
  72         major_num = major(stb.st_rdev);
  73         minor_num = minor(stb.st_rdev);
  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))
  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 (mknod(name, S_IFBLK | 0600, makedev(major_num, minor_num+i)))
  87                         perror("mknod");
  88                 if (chown(name, stb2.st_uid, stb2.st_gid))
  89                         perror("chown");
  90                 if (chmod(name, stb2.st_mode & 07777))
  91                         perror("chmod");
  92                 if (symlinks && strncmp(name, "/dev/md/", 8) == 0)
  93                         make_dev_symlink(name);
  94                 stat(name, &stb2);
  95                 add_dev(name, &stb2, 0, NULL);
  96         }
  97 }
  98
  99
 100 /*
 101  * We need a new md device to assemble/build/create an array.
 102  * 'dev' is a name given us by the user (command line or mdadm.conf)
 103  * It might start with /dev or /dev/md any might end with a digit
 104  * string.
 105  * If it starts with just /dev, it must be /dev/mdX or /dev/md_dX
 106  * If it ends with a digit string, then it must be as above, or
 107  * 'trustworthy' must be 'METADATA' and the 'dev' must be
 108  *  /dev/md/'name'NN or 'name'NN
 109  * If it doesn't end with a digit string, it must be /dev/md/'name'
 110  * or 'name' or must be NULL.
 111  * If the digit string is present, it gives the minor number to use
 112  * If not, we choose a high, unused minor number.
 113  * If the 'dev' is a standard name, it devices whether 'md' or 'mdp'.
 114  * else if the name is 'd[0-9]+' then we use mdp
 115  * else if trustworthy is 'METADATA' we use md
 116  * else the choice depends on 'autof'.
 117  * If name is NULL it is assumed to match whatever dev provides.
 118  * If both name and dev are NULL, we choose a name 'mdXX' or 'mdpXX'
 119  *
 120  * If 'name' is given, and 'trustworthy' is 'foreign' and name is not
 121  * supported by 'dev', we add a "_%d" suffix based on the minor number
 122  * use that.
 123  *
 124  * If udev is configured, we create a temporary device, open it, and
 125  * unlink it.
 126  * If not, we create the /dev/mdXX device, and is name is usable,
 127  * /dev/md/name
 128  * In any case we return /dev/md/name or (if that isn't available)
 129  * /dev/mdXX in 'chosen'.
 130  *
 131  * When we create devices, we use uid/gid/umask from config file.
 132  */
 133
 134 int create_mddev(char *dev, char *name, int autof, int trustworthy,
 135                  char *chosen)
 136 {
 137         int mdfd;
 138         struct stat stb;
 139         int num = -1;
 140         int use_mdp = -1;
 141         struct createinfo *ci = conf_get_create_info();
 142         int parts;
 143         char *cname;
 144         char devname[20];
 145         char cbuf[400];
 146         if (chosen == NULL)
 147                 chosen = cbuf;
 148
 149
 150         if (autof == 0)
 151                 autof = ci->autof;
 152
 153         parts = autof >> 3;
 154         autof &= 7;
 155
 156         strcpy(chosen, "/dev/md/");
 157         cname = chosen + strlen(chosen);
 158
 159
 160         if (dev) {
 161
 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                                 fprintf(stderr, Name ": %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                 } else
 185                         strcpy(cname, dev);
 186
 187                 /* 'cname' must not contain a slash, may not start or end
 188                  * with a digit, and may only be empty if num is present.
 189                  */
 190                 if (strchr(cname, '/') != NULL ||
 191                     isdigit(cname[0]) ||
 192                     (cname[0] && isdigit(cname[strlen(cname)]))
 193                         ) {
 194                         fprintf(stderr, Name ": %s is an invalid name "
 195                                 "for an md device.\n", dev);
 196                         return -1;
 197                 }
 198                 if (cname[0] == 0 && num < 0) {
 199                         fprintf(stderr, Name ": %s is an invalid name "
 200                                 "for an md device (empty!).", dev);
 201                         return -1;
 202                 }
 203         }
 204
 205         /* Now determine device number */
 206         /* named 'METADATA' cannot use 'mdp'. */
 207         if (name && name[0] == 0)
 208                 name = NULL;
 209         if (name && trustworthy == METADATA && use_mdp == 1) {
 210                 fprintf(stderr, Name ": %s is not allowed for a %s container. "
 211                         "Consider /dev/md%d.\n", dev, name, num);
 212                 return -1;
 213         }
 214         if (name && trustworthy == METADATA)
 215                 use_mdp = 0;
 216         if (use_mdp == -1) {
 217                 if (autof == 4 || autof == 6)
 218                         use_mdp = 1;
 219                 else
 220                         use_mdp = 0;
 221         }
 222         if (num < 0 && trustworthy == LOCAL && name) {
 223                 /* if name is numeric, us that for num */
 224                 char *ep;
 225                 num = strtoul(name, &ep, 10);
 226                 if (ep == name || *ep)
 227                         num = -1;
 228         }
 229
 230         if (num < 0) {
 231                 /* need to choose a free number. */
 232                 num = find_free_devnum(use_mdp);
 233                 if (num == NoMdDev) {
 234                         fprintf(stderr, Name ": No avail md devices - aborting\n");
 235                         return -1;
 236                 }
 237         } else {
 238                 num = use_mdp ? (-1-num) : num;
 239                 if (mddev_busy(num)) {
 240                         fprintf(stderr, Name ": %s is already in use.\n",
 241                                 dev);
 242                         return -1;
 243                 }
 244         }
 245
 246         if (num < 0)
 247                 sprintf(devname, "/dev/md_d%d", -1-num);
 248         else
 249                 sprintf(devname, "/dev/md%d", num);
 250
 251         if (cname[0] == 0 && name) {
 252                 /* Need to find a name if we can
 253                  * We don't completely trust 'name'.  Truncate to
 254                  * reasonable length and remove '/'
 255                  */
 256                 char *cp;
 257                 strncpy(cname, name, 200);
 258                 cname[200] = 0;
 259                 while ((cp = strchr(cname, '/')) != NULL)
 260                         *cp = '-';
 261                 if (trustworthy == METADATA)
 262                         /* always add device number to metadata */
 263                         sprintf(cname+strlen(cname), "%d", num);
 264                 else if (trustworthy == FOREIGN &&
 265                          strchr(cname, ':') == NULL)
 266                         /* add _%d to FOREIGN array that don't have
 267                          * a 'host:' prefix
 268                          */
 269                         sprintf(cname+strlen(cname), "_%d", num<0?(-1-num):num);
 270         }
 271         if (cname[0] == 0)
 272                 strcpy(chosen, devname);
 273
 274         /* We have a device number and name.
 275          * If we can detect udev, just open the device and we
 276          * are done.
 277          */
 278         if (stat("/dev/.udev", &stb) != 0 ||
 279             check_env("MDADM_NO_UDEV")) {
 280                 /* Make sure 'devname' exists and 'chosen' is a symlink to it */
 281                 if (lstat(devname, &stb) == 0) {
 282                         /* Must be the correct device, else error */
 283                         if ((stb.st_mode&S_IFMT) != S_IFBLK ||
 284                             stb.st_rdev != makedev(dev2major(num),dev2minor(num))) {
 285                                 fprintf(stderr, Name ": %s exists but looks wrong, please fix\n",
 286                                         devname);
 287                                 return -1;
 288                         }
 289                 } else {
 290                         if (mknod(devname, S_IFBLK|0600,
 291                                   makedev(dev2major(num),dev2minor(num))) != 0) {
 292                                 fprintf(stderr, Name ": failed to create %s\n",
 293                                         devname);
 294                                 return -1;
 295                         }
 296                         if (chown(devname, ci->uid, ci->gid))
 297                                 perror("chown");
 298                         if (chmod(devname, ci->mode))
 299                                 perror("chmod");
 300                         stat(devname, &stb);
 301                         add_dev(devname, &stb, 0, NULL);
 302                 }
 303                 if (strcmp(chosen, devname) != 0) {
 304
 305                         if (mkdir("/dev/md",0700)==0) {
 306                                 if (chown("/dev/md", ci->uid, ci->gid))
 307                                         perror("chown /dev/md");
 308                                 if (chmod("/dev/md", ci->mode| ((ci->mode>>2) & 0111)))
 309                                         perror("chmod /dev/md");
 310                         }
 311
 312                         if (dev && strcmp(chosen, dev) == 0)
 313                                 /* We know we are allowed to use this name */
 314                                 unlink(chosen);
 315
 316                         if (lstat(chosen, &stb) == 0) {
 317                                 char buf[300];
 318                                 if ((stb.st_mode & S_IFMT) != S_IFLNK ||
 319                                     readlink(chosen, buf, 300) <0 ||
 320                                     strcmp(buf, devname) != 0) {
 321                                         fprintf(stderr, Name ": %s exists - ignoring\n",
 322                                                 chosen);
 323                                         strcpy(chosen, devname);
 324                                 }
 325                         } else
 326                                 symlink(devname, chosen);
 327                 }
 328         }
 329         mdfd = open_dev_excl(num);
 330         if (mdfd < 0)
 331                 fprintf(stderr, Name ": unexpected failure opening %s\n",
 332                         devname);
 333         return mdfd;
 334 }
 335
 336
 337 /* Open this and check that it is an md device.
 338  * On success, return filedescriptor.
 339  * On failure, return -1 if it doesn't exist,
 340  * or -2 if it exists but is not an md device.
 341  */
 342 int open_mddev(char *dev, int report_errors)
 343 {
 344         int mdfd = open(dev, O_RDWR);
 345         if (mdfd < 0) {
 346                 if (report_errors)
 347                         fprintf(stderr, Name ": error opening %s: %s\n",
 348                                 dev, strerror(errno));
 349                 return -1;
 350         }
 351         if (md_get_version(mdfd) <= 0) {
 352                 close(mdfd);
 353                 if (report_errors)
 354                         fprintf(stderr, Name ": %s does not appear to be "
 355                                 "an md device\n", dev);
 356                 return -2;
 357         }
 358         return mdfd;
 359 }
 360
 361
 362 int create_mddev_devnum(char *devname, int devnum, char *name,
 363                       char *chosen_name, int parts)
 364 {
 365         /* Open the md device with number 'devnum', possibly using 'devname',
 366          * possibly constructing a name with 'name', but in any case, copying
 367          * the name into 'chosen_name'
 368          */
 369         int major_num, minor_num;
 370         struct stat stb;
 371         int i;
 372         struct createinfo *ci = conf_get_create_info();
 373
 374         if (devname)
 375                 strcpy(chosen_name, devname);
 376         else if (name && *name && name[0] && strchr(name,'/') == NULL) {
 377                 char *n = strchr(name, ':');
 378                 if (n) n++; else n = name;
 379                 if (isdigit(*n) && devnum < 0)
 380                         sprintf(chosen_name, "/dev/md/d%s", n);
 381                 else
 382                         sprintf(chosen_name, "/dev/md/%s", n);
 383         } else {
 384                 if (devnum >= 0)
 385                         sprintf(chosen_name, "/dev/md%d", devnum);
 386                 else
 387                         sprintf(chosen_name, "/dev/md/d%d", -1-devnum);
 388         }
 389         if (devnum >= 0) {
 390                 major_num = MD_MAJOR;
 391                 minor_num = devnum;
 392         } else {
 393                 major_num = get_mdp_major();
 394                 minor_num = (-1-devnum) << 6;
 395         }
 396         if (stat(chosen_name, &stb) == 0) {
 397                 /* It already exists.  Check it is right. */
 398                 if ( ! S_ISBLK(stb.st_mode) ||
 399                      stb.st_rdev != makedev(major_num, minor_num)) {
 400                         errno = EEXIST;
 401                         return -1;
 402                 }
 403         } else {
 404                 /* special case: if --incremental is suggesting a name
 405                  * in /dev/md/, we make sure the directory exists.
 406                  */
 407                 if (strncmp(chosen_name, "/dev/md/", 8) == 0) {
 408                         if (mkdir("/dev/md",0700)==0) {
 409                                 if (chown("/dev/md", ci->uid, ci->gid))
 410                                         perror("chown /dev/md");
 411                                 if (chmod("/dev/md", ci->mode|
 412                                                   ((ci->mode>>2) & 0111)))
 413                                         perror("chmod /dev/md");
 414                         }
 415                 }
 416
 417                 if (mknod(chosen_name, S_IFBLK | 0600,
 418                           makedev(major_num, minor_num)) != 0) {
 419                         return -1;
 420                 }
 421                 /* FIXME chown/chmod ?? */
 422         }
 423
 424         /* Simple locking to avoid --incr being called for the same
 425          * array multiple times in parallel.
 426          */
 427         for (i = 0; i < 25 ; i++) {
 428                 int fd;
 429
 430                 fd = open(chosen_name, O_RDWR|O_EXCL);
 431                 if (fd >= 0 || errno != EBUSY) {
 432                         if (devnum < 0)
 433                                 make_parts(chosen_name, parts, ci->symlinks);
 434                         return fd;
 435                 }
 436                 usleep(200000);
 437         }
 438         return -1;
 439 }