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_parts(char *dev, int cnt)
  36 {
  37         /* make 'cnt' partition devices for 'dev'
  38          * If dev is a device name we use the
  39          *  major/minor from dev and add 1..cnt
  40          * If it is a symlink, we make similar symlinks.
  41          * If dev ends with a digit, we add "p%d" else "%d"
  42          * If the name exists, we use it's owner/mode,
  43          * else that of dev
  44          */
  45         struct stat stb;
  46         int major_num, minor_num;
  47         int i;
  48         int nlen = strlen(dev) + 20;
  49         char *name = malloc(nlen);
  50         int dig = isdigit(dev[strlen(dev)-1]);
  51         char orig[1024];
  52         char sym[1024];
  53         int odig;
  54
  55         if (cnt==0) cnt=4;
  56         if (lstat(dev, &stb)!= 0)
  57                 return;
  58         if (S_ISLNK(stb.st_mode)) {
  59                 int len = readlink(dev, orig, sizeof(orig));
  60                 if (len < 0 || len > 1000)
  61                         return;
  62                 orig[len] = 0;
  63                 odig = isdigit(orig[len-1]);
  64         } else if (S_ISBLK(stb.st_mode)) {
  65                 major_num = major(stb.st_rdev);
  66                 minor_num = minor(stb.st_rdev);
  67         } else
  68                    return;
  69         for (i=1; i <= cnt ; i++) {
  70                 struct stat stb2;
  71                 snprintf(name, nlen, "%s%s%d", dev, dig?"p":"", i);
  72                 if (stat(name, &stb2)==0) {
  73                         if (!S_ISBLK(stb2.st_mode))
  74                                 continue;
  75                         if (stb2.st_rdev == makedev(major_num, minor_num+i))
  76                                 continue;
  77                         unlink(name);
  78                 } else {
  79                         stb2 = stb;
  80                 }
  81                 if (S_ISBLK(stb.st_mode)) {
  82                         if (mknod(name, S_IFBLK | 0600,
  83                                   makedev(major_num, minor_num+i)))
  84                                 perror("mknod");
  85                         if (chown(name, stb2.st_uid, stb2.st_gid))
  86                                 perror("chown");
  87                         if (chmod(name, stb2.st_mode & 07777))
  88                                 perror("chmod");
  89                 } else {
  90                         snprintf(sym, 10000, "%s%s%d", orig, odig?"p":"", i);
  91                         symlink(sym, name);
  92                 }
  93                 stat(name, &stb2);
  94                 add_dev(name, &stb2, 0, NULL);
  95         }
  96 }
  97
  98
  99 /*
 100  * We need a new md device to assemble/build/create an array.
 101  * 'dev' is a name given us by the user (command line or mdadm.conf)
 102  * It might start with /dev or /dev/md any might end with a digit
 103  * string.
 104  * If it starts with just /dev, it must be /dev/mdX or /dev/md_dX
 105  * If it ends with a digit string, then it must be as above, or
 106  * 'trustworthy' must be 'METADATA' and the 'dev' must be
 107  *  /dev/md/'name'NN or 'name'NN
 108  * If it doesn't end with a digit string, it must be /dev/md/'name'
 109  * or 'name' or must be NULL.
 110  * If the digit string is present, it gives the minor number to use
 111  * If not, we choose a high, unused minor number.
 112  * If the 'dev' is a standard name, it devices whether 'md' or 'mdp'.
 113  * else if the name is 'd[0-9]+' then we use mdp
 114  * else if trustworthy is 'METADATA' we use md
 115  * else the choice depends on 'autof'.
 116  * If name is NULL it is assumed to match whatever dev provides.
 117  * If both name and dev are NULL, we choose a name 'mdXX' or 'mdpXX'
 118  *
 119  * If 'name' is given, and 'trustworthy' is 'foreign' and name is not
 120  * supported by 'dev', we add a "_%d" suffix based on the minor number
 121  * use that.
 122  *
 123  * If udev is configured, we create a temporary device, open it, and
 124  * unlink it.
 125  * If not, we create the /dev/mdXX device, and is name is usable,
 126  * /dev/md/name
 127  * In any case we return /dev/md/name or (if that isn't available)
 128  * /dev/mdXX in 'chosen'.
 129  *
 130  * When we create devices, we use uid/gid/umask from config file.
 131  */
 132
 133 int create_mddev(char *dev, char *name, int autof, int trustworthy,
 134                  char *chosen)
 135 {
 136         int mdfd;
 137         struct stat stb;
 138         int num = -1;
 139         int use_mdp = -1;
 140         struct createinfo *ci = conf_get_create_info();
 141         int parts;
 142         char *cname;
 143         char devname[20];
 144         char cbuf[400];
 145         if (chosen == NULL)
 146                 chosen = cbuf;
 147
 148
 149         if (autof == 0)
 150                 autof = ci->autof;
 151
 152         parts = autof >> 3;
 153         autof &= 7;
 154
 155         strcpy(chosen, "/dev/md/");
 156         cname = chosen + strlen(chosen);
 157
 158
 159         if (dev) {
 160
 161                 if (strncmp(dev, "/dev/md/", 8) == 0) {
 162                         strcpy(cname, dev+8);
 163                 } else if (strncmp(dev, "/dev/", 5) == 0) {
 164                         char *e = dev + strlen(dev);
 165                         while (e > dev && isdigit(e[-1]))
 166                                 e--;
 167                         if (e[0])
 168                                 num = strtoul(e, NULL, 10);
 169                         strcpy(cname, dev+5);
 170                         cname[e-(dev+5)] = 0;
 171                         /* name *must* be mdXX or md_dXX in this context */
 172                         if (num < 0 ||
 173                             (strcmp(cname, "md") != 0 && strcmp(cname, "md_d") != 0)) {
 174                                 fprintf(stderr, Name ": %s is an invalid name "
 175                                         "for an md device.  Try /dev/md/%s\n",
 176                                         dev, dev+5);
 177                                 return -1;
 178                         }
 179                         if (strcmp(cname, "md") == 0)
 180                                 use_mdp = 0;
 181                         else
 182                                 use_mdp = 1;
 183                 } else
 184                         strcpy(cname, dev);
 185
 186                 /* 'cname' must not contain a slash, may not start or end
 187                  * with a digit, and may only be empty if num is present.
 188                  */
 189                 if (strchr(cname, '/') != NULL ||
 190                     isdigit(cname[0]) ||
 191                     (cname[0] && isdigit(cname[strlen(cname)]))
 192                         ) {
 193                         fprintf(stderr, Name ": %s is an invalid name "
 194                                 "for an md device.\n", dev);
 195                         return -1;
 196                 }
 197                 if (cname[0] == 0 && num < 0) {
 198                         fprintf(stderr, Name ": %s is an invalid name "
 199                                 "for an md device (empty!).", dev);
 200                         return -1;
 201                 }
 202         }
 203
 204         /* Now determine device number */
 205         /* named 'METADATA' cannot use 'mdp'. */
 206         if (name && name[0] == 0)
 207                 name = NULL;
 208         if (name && trustworthy == METADATA && use_mdp == 1) {
 209                 fprintf(stderr, Name ": %s is not allowed for a %s container. "
 210                         "Consider /dev/md%d.\n", dev, name, num);
 211                 return -1;
 212         }
 213         if (name && trustworthy == METADATA)
 214                 use_mdp = 0;
 215         if (use_mdp == -1) {
 216                 if (autof == 4 || autof == 6)
 217                         use_mdp = 1;
 218                 else
 219                         use_mdp = 0;
 220         }
 221         if (num < 0 && trustworthy == LOCAL && name) {
 222                 /* if name is numeric, us that for num */
 223                 char *ep;
 224                 num = strtoul(name, &ep, 10);
 225                 if (ep == name || *ep)
 226                         num = -1;
 227         }
 228
 229         if (num < 0) {
 230                 /* need to choose a free number. */
 231                 num = find_free_devnum(use_mdp);
 232                 if (num == NoMdDev) {
 233                         fprintf(stderr, Name ": No avail md devices - aborting\n");
 234                         return -1;
 235                 }
 236         } else {
 237                 num = use_mdp ? (-1-num) : num;
 238                 if (mddev_busy(num)) {
 239                         fprintf(stderr, Name ": %s is already in use.\n",
 240                                 dev);
 241                         return -1;
 242                 }
 243         }
 244
 245         if (num < 0)
 246                 sprintf(devname, "/dev/md_d%d", -1-num);
 247         else
 248                 sprintf(devname, "/dev/md%d", num);
 249
 250         if (cname[0] == 0 && name) {
 251                 /* Need to find a name if we can
 252                  * We don't completely trust 'name'.  Truncate to
 253                  * reasonable length and remove '/'
 254                  */
 255                 char *cp;
 256                 strncpy(cname, name, 200);
 257                 cname[200] = 0;
 258                 while ((cp = strchr(cname, '/')) != NULL)
 259                         *cp = '-';
 260                 if (trustworthy == METADATA)
 261                         /* always add device number to metadata */
 262                         sprintf(cname+strlen(cname), "%d", num);
 263                 else if (trustworthy == FOREIGN &&
 264                          strchr(cname, ':') == NULL)
 265                         /* add _%d to FOREIGN array that don't have
 266                          * a 'host:' prefix
 267                          */
 268                         sprintf(cname+strlen(cname), "_%d", num<0?(-1-num):num);
 269         }
 270         if (cname[0] == 0)
 271                 strcpy(chosen, devname);
 272
 273         /* We have a device number and name.
 274          * If we can detect udev, just open the device and we
 275          * are done.
 276          */
 277         if (stat("/dev/.udev", &stb) != 0 ||
 278             check_env("MDADM_NO_UDEV")) {
 279                 /* Make sure 'devname' exists and 'chosen' is a symlink to it */
 280                 if (lstat(devname, &stb) == 0) {
 281                         /* Must be the correct device, else error */
 282                         if ((stb.st_mode&S_IFMT) != S_IFBLK ||
 283                             stb.st_rdev != makedev(dev2major(num),dev2minor(num))) {
 284                                 fprintf(stderr, Name ": %s exists but looks wrong, please fix\n",
 285                                         devname);
 286                                 return -1;
 287                         }
 288                 } else {
 289                         if (mknod(devname, S_IFBLK|0600,
 290                                   makedev(dev2major(num),dev2minor(num))) != 0) {
 291                                 fprintf(stderr, Name ": failed to create %s\n",
 292                                         devname);
 293                                 return -1;
 294                         }
 295                         if (chown(devname, ci->uid, ci->gid))
 296                                 perror("chown");
 297                         if (chmod(devname, ci->mode))
 298                                 perror("chmod");
 299                         stat(devname, &stb);
 300                         add_dev(devname, &stb, 0, NULL);
 301                 }
 302                 if (use_mdp == 1)
 303                         make_parts(devname, parts);
 304                 if (strcmp(chosen, devname) != 0) {
 305
 306                         if (mkdir("/dev/md",0700)==0) {
 307                                 if (chown("/dev/md", ci->uid, ci->gid))
 308                                         perror("chown /dev/md");
 309                                 if (chmod("/dev/md", ci->mode| ((ci->mode>>2) & 0111)))
 310                                         perror("chmod /dev/md");
 311                         }
 312
 313                         if (dev && strcmp(chosen, dev) == 0)
 314                                 /* We know we are allowed to use this name */
 315                                 unlink(chosen);
 316
 317                         if (lstat(chosen, &stb) == 0) {
 318                                 char buf[300];
 319                                 if ((stb.st_mode & S_IFMT) != S_IFLNK ||
 320                                     readlink(chosen, buf, 300) <0 ||
 321                                     strcmp(buf, devname) != 0) {
 322                                         fprintf(stderr, Name ": %s exists - ignoring\n",
 323                                                 chosen);
 324                                         strcpy(chosen, devname);
 325                                 }
 326                         } else
 327                                 symlink(devname, chosen);
 328                         if (use_mdp && strcmp(chosen, devname) != 0)
 329                                 make_parts(chosen, parts);
 330                 }
 331         }
 332         mdfd = open_dev_excl(num);
 333         if (mdfd < 0)
 334                 fprintf(stderr, Name ": unexpected failure opening %s\n",
 335                         devname);
 336         return mdfd;
 337 }
 338
 339
 340 /* Open this and check that it is an md device.
 341  * On success, return filedescriptor.
 342  * On failure, return -1 if it doesn't exist,
 343  * or -2 if it exists but is not an md device.
 344  */
 345 int open_mddev(char *dev, int report_errors)
 346 {
 347         int mdfd = open(dev, O_RDWR);
 348         if (mdfd < 0) {
 349                 if (report_errors)
 350                         fprintf(stderr, Name ": error opening %s: %s\n",
 351                                 dev, strerror(errno));
 352                 return -1;
 353         }
 354         if (md_get_version(mdfd) <= 0) {
 355                 close(mdfd);
 356                 if (report_errors)
 357                         fprintf(stderr, Name ": %s does not appear to be "
 358                                 "an md device\n", dev);
 359                 return -2;
 360         }
 361         return mdfd;
 362 }
 363
 364
 365 int create_mddev_devnum(char *devname, int devnum, char *name,
 366                       char *chosen_name, int parts)
 367 {
 368         /* Open the md device with number 'devnum', possibly using 'devname',
 369          * possibly constructing a name with 'name', but in any case, copying
 370          * the name into 'chosen_name'
 371          */
 372         int major_num, minor_num;
 373         struct stat stb;
 374         int i;
 375         struct createinfo *ci = conf_get_create_info();
 376
 377         if (devname)
 378                 strcpy(chosen_name, devname);
 379         else if (name && *name && name[0] && strchr(name,'/') == NULL) {
 380                 char *n = strchr(name, ':');
 381                 if (n) n++; else n = name;
 382                 if (isdigit(*n) && devnum < 0)
 383                         sprintf(chosen_name, "/dev/md/d%s", n);
 384                 else
 385                         sprintf(chosen_name, "/dev/md/%s", n);
 386         } else {
 387                 if (devnum >= 0)
 388                         sprintf(chosen_name, "/dev/md%d", devnum);
 389                 else
 390                         sprintf(chosen_name, "/dev/md/d%d", -1-devnum);
 391         }
 392         if (devnum >= 0) {
 393                 major_num = MD_MAJOR;
 394                 minor_num = devnum;
 395         } else {
 396                 major_num = get_mdp_major();
 397                 minor_num = (-1-devnum) << 6;
 398         }
 399         if (stat(chosen_name, &stb) == 0) {
 400                 /* It already exists.  Check it is right. */
 401                 if ( ! S_ISBLK(stb.st_mode) ||
 402                      stb.st_rdev != makedev(major_num, minor_num)) {
 403                         errno = EEXIST;
 404                         return -1;
 405                 }
 406         } else {
 407                 /* special case: if --incremental is suggesting a name
 408                  * in /dev/md/, we make sure the directory exists.
 409                  */
 410                 if (strncmp(chosen_name, "/dev/md/", 8) == 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|
 415                                                   ((ci->mode>>2) & 0111)))
 416                                         perror("chmod /dev/md");
 417                         }
 418                 }
 419
 420                 if (mknod(chosen_name, S_IFBLK | 0600,
 421                           makedev(major_num, minor_num)) != 0) {
 422                         return -1;
 423                 }
 424                 /* FIXME chown/chmod ?? */
 425         }
 426
 427         /* Simple locking to avoid --incr being called for the same
 428          * array multiple times in parallel.
 429          */
 430         for (i = 0; i < 25 ; i++) {
 431                 int fd;
 432
 433                 fd = open(chosen_name, O_RDWR|O_EXCL);
 434                 if (fd >= 0 || errno != EBUSY) {
 435                         if (devnum < 0)
 436                                 make_parts(chosen_name, parts);
 437                         return fd;
 438                 }
 439                 usleep(200000);
 440         }
 441         return -1;
 442 }