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 = major_num; /* quiet gcc -Os unitialized warning */
  47         int minor_num = minor_num; /* quiet gcc -Os unitialized warning */
  48         int odig = odig; /* quiet gcc -Os unitialized warning */
  49         int i;
  50         int nlen = strlen(dev) + 20;
  51         char *name = malloc(nlen);
  52         int dig = isdigit(dev[strlen(dev)-1]);
  53         char orig[1024];
  54         char sym[1024];
  55         int err;
  56
  57         if (cnt==0) cnt=4;
  58         if (lstat(dev, &stb)!= 0)
  59                 return;
  60         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         } else if (S_ISBLK(stb.st_mode)) {
  67                 major_num = major(stb.st_rdev);
  68                 minor_num = minor(stb.st_rdev);
  69         } else
  70                    return;
  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))
  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 }
 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
 153         if (autof == 0)
 154                 autof = ci->autof;
 155
 156         parts = autof >> 3;
 157         autof &= 7;
 158
 159         strcpy(chosen, "/dev/md/");
 160         cname = chosen + strlen(chosen);
 161
 162
 163         if (dev) {
 164
 165                 if (strncmp(dev, "/dev/md/", 8) == 0) {
 166                         strcpy(cname, dev+8);
 167                 } else if (strncmp(dev, "/dev/", 5) == 0) {
 168                         char *e = dev + strlen(dev);
 169                         while (e > dev && isdigit(e[-1]))
 170                                 e--;
 171                         if (e[0])
 172                                 num = strtoul(e, NULL, 10);
 173                         strcpy(cname, dev+5);
 174                         cname[e-(dev+5)] = 0;
 175                         /* name *must* be mdXX or md_dXX in this context */
 176                         if (num < 0 ||
 177                             (strcmp(cname, "md") != 0 && strcmp(cname, "md_d") != 0)) {
 178                                 fprintf(stderr, Name ": %s is an invalid name "
 179                                         "for an md device.  Try /dev/md/%s\n",
 180                                         dev, dev+5);
 181                                 return -1;
 182                         }
 183                         if (strcmp(cname, "md") == 0)
 184                                 use_mdp = 0;
 185                         else
 186                                 use_mdp = 1;
 187                         /* recreate name: /dev/md/0 or /dev/md/d0 */
 188                         sprintf(cname, "%s%d", use_mdp?"d":"", num);
 189                 } else
 190                         strcpy(cname, dev);
 191
 192                 /* 'cname' must not contain a slash, and may not be
 193                  * empty.
 194                  */
 195                 if (strchr(cname, '/') != NULL) {
 196                         fprintf(stderr, Name ": %s is an invalid name "
 197                                 "for an md device.\n", dev);
 198                         return -1;
 199                 }
 200                 if (cname[0] == 0) {
 201                         fprintf(stderr, Name ": %s is an invalid name "
 202                                 "for an md device (empty!).", dev);
 203                         return -1;
 204                 }
 205                 if (num < 0) {
 206                         /* If cname  is 'N' or 'dN', we get dev number
 207                          * from there.
 208                          */
 209                         char *sp = cname;
 210                         char *ep;
 211                         if (cname[0] == 'd')
 212                                 sp++;
 213                         num = strtoul(sp, &ep, 10);
 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                 fprintf(stderr, Name ": %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                         fprintf(stderr, Name ": 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                         fprintf(stderr, Name ": %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                 while ((cp = strchr(cname, '/')) != NULL)
 293                         *cp = '-';
 294                 if (trustworthy == LOCAL ||
 295                     (trustworthy == FOREIGN && strchr(cname, ':') != NULL)) {
 296                         /* Only need suffix if there is a conflict */
 297                         if (map_by_name(&map, cname) == NULL)
 298                                 conflict = 0;
 299                 }
 300                 cnlen = strlen(cname);
 301                 while (conflict) {
 302                         if (trustworthy == METADATA && !isdigit(cname[cnlen-1]))
 303                                 sprintf(cname+cnlen, "%d", unum);
 304                         else
 305                                 /* add _%d to FOREIGN array that don't
 306                                  * a 'host:' prefix
 307                                  */
 308                                 sprintf(cname+cnlen, "_%d", unum);
 309                         unum++;
 310                         if (map_by_name(&map, cname) == NULL)
 311                                 conflict = 0;
 312                 }
 313         }
 314         if (cname[0] == 0)
 315                 strcpy(chosen, devname);
 316
 317         /* We have a device number and name.
 318          * If we cannot detect udev, we need to make
 319          * devices and links ourselves.
 320          */
 321         if (stat("/dev/.udev", &stb) != 0 ||
 322             check_env("MDADM_NO_UDEV")) {
 323                 /* Make sure 'devname' exists and 'chosen' is a symlink to it */
 324                 if (lstat(devname, &stb) == 0) {
 325                         /* Must be the correct device, else error */
 326                         if ((stb.st_mode&S_IFMT) != S_IFBLK ||
 327                             stb.st_rdev != makedev(dev2major(num),dev2minor(num))) {
 328                                 fprintf(stderr, Name ": %s exists but looks wrong, please fix\n",
 329                                         devname);
 330                                 return -1;
 331                         }
 332                 } else {
 333                         if (mknod(devname, S_IFBLK|0600,
 334                                   makedev(dev2major(num),dev2minor(num))) != 0) {
 335                                 fprintf(stderr, Name ": failed to create %s\n",
 336                                         devname);
 337                                 return -1;
 338                         }
 339                         if (chown(devname, ci->uid, ci->gid))
 340                                 perror("chown");
 341                         if (chmod(devname, ci->mode))
 342                                 perror("chmod");
 343                         stat(devname, &stb);
 344                         add_dev(devname, &stb, 0, NULL);
 345                 }
 346                 if (use_mdp == 1)
 347                         make_parts(devname, parts);
 348                 if (strcmp(chosen, devname) != 0) {
 349
 350                         if (mkdir("/dev/md",0700)==0) {
 351                                 if (chown("/dev/md", ci->uid, ci->gid))
 352                                         perror("chown /dev/md");
 353                                 if (chmod("/dev/md", ci->mode| ((ci->mode>>2) & 0111)))
 354                                         perror("chmod /dev/md");
 355                         }
 356
 357                         if (dev && strcmp(chosen, dev) == 0)
 358                                 /* We know we are allowed to use this name */
 359                                 unlink(chosen);
 360
 361                         if (lstat(chosen, &stb) == 0) {
 362                                 char buf[300];
 363                                 if ((stb.st_mode & S_IFMT) != S_IFLNK ||
 364                                     readlink(chosen, buf, 300) <0 ||
 365                                     strcmp(buf, devname) != 0) {
 366                                         fprintf(stderr, Name ": %s exists - ignoring\n",
 367                                                 chosen);
 368                                         strcpy(chosen, devname);
 369                                 }
 370                         } else if (symlink(devname, chosen) != 0)
 371                                 fprintf(stderr, Name ": failed to create %s: %s\n",
 372                                         chosen, strerror(errno));
 373                         if (use_mdp && strcmp(chosen, devname) != 0)
 374                                 make_parts(chosen, parts);
 375                 }
 376         }
 377         mdfd = open_dev_excl(num);
 378         if (mdfd < 0)
 379                 fprintf(stderr, Name ": unexpected failure opening %s\n",
 380                         devname);
 381         return mdfd;
 382 }
 383
 384
 385 /* Open this and check that it is an md device.
 386  * On success, return filedescriptor.
 387  * On failure, return -1 if it doesn't exist,
 388  * or -2 if it exists but is not an md device.
 389  */
 390 int open_mddev(char *dev, int report_errors)
 391 {
 392         int mdfd = open(dev, O_RDWR);
 393         if (mdfd < 0) {
 394                 if (report_errors)
 395                         fprintf(stderr, Name ": error opening %s: %s\n",
 396                                 dev, strerror(errno));
 397                 return -1;
 398         }
 399         if (md_get_version(mdfd) <= 0) {
 400                 close(mdfd);
 401                 if (report_errors)
 402                         fprintf(stderr, Name ": %s does not appear to be "
 403                                 "an md device\n", dev);
 404                 return -2;
 405         }
 406         return mdfd;
 407 }