mdopen.c

   1 /*
   2  * mdadm - manage Linux "md" devices aka RAID arrays.
   3  *
   4  * Copyright (C) 2001-2002 Neil Brown <neilb@cse.unsw.edu.au>
   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 void make_parts(char *dev, int cnt)
  35 {
  36         /* make 'cnt' partition devices for 'dev'
  37          * We use the major/minor from dev and add 1..cnt
  38          * If dev ends with a digit, we add "p%d" else "%d"
  39          * If the name exists, we use it's owner/mode,
  40          * else that of dev
  41          */
  42         struct stat stb;
  43         int major, minor;
  44         int i;
  45         char *name = malloc(strlen(dev) + 20);
  46         int dig = isdigit(dev[strlen(dev)-1]);
  47
  48         if (stat(dev, &stb)!= 0)
  49                 return;
  50         if (!S_ISBLK(stb.st_mode))
  51                 return;
  52         major = major(stb.st_rdev);
  53         minor = minor(stb.st_rdev);
  54         for (i=1; i <= cnt ; i++) {
  55                 struct stat stb2;
  56                 sprintf(name, "%s%s%d", dev, dig?"p":"", i);
  57                 if (stat(name, &stb2)==0) {
  58                         if (!S_ISBLK(stb2.st_mode))
  59                                 continue;
  60                         if (stb2.st_rdev == makedev(major, minor+i))
  61                                 continue;
  62                         unlink(name);
  63                 } else {
  64                         stb2 = stb;
  65                 }
  66                 mknod(name, S_IFBLK | 0600, makedev(major, minor+i));
  67                 chown(name, stb2.st_uid, stb2.st_gid);
  68                 chmod(name, stb2.st_mode & 07777);
  69         }
  70 }
  71
  72 /*
  73  * Open a given md device, and check that it really is one.
  74  * If 'autof' is given, then we need to create, or recreate, the md device.
  75  * If the name already exists, and is not a block device, we fail.
  76  * If it exists and is not an md device, is not the right type (partitioned or not),
  77  * or is currently in-use, we remove the device, but remember the owner and mode.
  78  * If it now doesn't exist, we find a new md array and create the device.
  79  * Default ownership is user=0, group=0 perm=0600
  80  */
  81 int open_mddev(char *dev, int autof)
  82 {
  83         int mdfd;
  84         struct stat stb;
  85         int major = MD_MAJOR;
  86         int minor;
  87         int must_remove = 0;
  88         struct mdstat_ent *mdlist;
  89         int num;
  90
  91         if (autof) {
  92                 /* autof is set, so we need to check that the name is ok,
  93                  * and possibly create one if not
  94                  */
  95                 stb.st_mode = 0;
  96                 if (lstat(dev, &stb)==0 && ! S_ISBLK(stb.st_mode)) {
  97                         fprintf(stderr, Name ": %s is not a block device.\n",
  98                                 dev);
  99                         return -1;
 100                 }
 101                 /* check major number is correct */
 102                 if (autof>0)
 103                         major = get_mdp_major();
 104                 if (stb.st_mode && major(stb.st_rdev) != major)
 105                         must_remove = 1;
 106                 if (stb.st_mode && !must_remove) {
 107                         mdu_array_info_t array;
 108                         /* looks ok, see if it is available */
 109                         mdfd = open(dev, O_RDWR, 0);
 110                         if (mdfd < 0) {
 111                                 fprintf(stderr, Name ": error opening %s: %s\n",
 112                                         dev, strerror(errno));
 113                                 return -1;
 114                         } else if (md_get_version(mdfd) <= 0) {
 115                                 fprintf(stderr, Name ": %s does not appear to be an md device\n",
 116                                         dev);
 117                                 close(mdfd);
 118                                 return -1;
 119                         }
 120                         if (ioctl(mdfd, GET_ARRAY_INFO, &array)==0) {
 121                                 /* already active */
 122                                 must_remove = 1;
 123                                 close(mdfd);
 124                         } else {
 125                                 if (autof > 0)
 126                                         make_parts(dev, autof);
 127                                 return mdfd;
 128                         }
 129                 }
 130                 /* Ok, need to find a minor that is not in use.
 131                  * If the device name is in a 'standard' format,
 132                  * intuit the minor from that, else
 133                  * easiest to read /proc/mdstat, and hunt through for
 134                  * an unused number
 135                  */
 136                 switch(is_standard(dev, &num)) {
 137                 case -1: /* non partitioned */
 138                         if (autof > 0) {
 139                                 fprintf(stderr, Name ": that --auto option not compatable with device named %s\n", dev);
 140                                 return -1;
 141                         }
 142                         minor = num;
 143                         num = -1-num;
 144                         break;
 145                 case 1: /* partitioned */
 146                         if (autof == -1) {
 147                                 fprintf(stderr, Name ": that --auto option not compatable with device named %s\n", dev);
 148                                 return -1;
 149                         }
 150                         minor = num <<  MdpMinorShift;
 151                         major = get_mdp_major();
 152                         break;
 153                 case 0: /* not standard, pick an unused number */
 154                         mdlist = mdstat_read(0);
 155                         for (num= (autof>0)?-1:0 ; ; num+= (autof>2)?-1:1) {
 156                                 struct mdstat_ent *me;
 157                                 for (me=mdlist; me; me=me->next)
 158                                         if (me->devnum == num)
 159                                                 break;
 160                                 if (!me) {
 161                                         /* doesn't exist if mdstat.
 162                                          * make sure it is new to /dev too
 163                                          */
 164                                         char *dn;
 165                                         if (autof > 0)
 166                                                 minor = (-1-num) << MdpMinorShift;
 167                                         else
 168                                                 minor = num;
 169                                         dn = map_dev(major,minor);
 170                                         if (dn==NULL || is_standard(dn, NULL)) {
 171                                                 /* this number only used by a 'standard' name,
 172                                                  * so it is safe to use
 173                                                  */
 174                                                 break;
 175                                         }
 176                                 }
 177                         }
 178                 }
 179                 /* major and minor have been chosen */
 180
 181                 /* If it was a 'standard' name and it is in-use, then
 182                  * the device could already be correct
 183                  */
 184                 if (stb.st_mode && major(stb.st_rdev) == major &&
 185                     minor(stb.st_rdev) == minor)
 186                         ;
 187                 else {
 188                         if (major(makedev(major,minor)) != major ||
 189                             minor(makedev(major,minor)) != minor) {
 190                                 fprintf(stderr, Name ": Need newer C library to use more than 4 partitionable md devices, sorry\n");
 191                                 return -1;
 192                         }
 193                         if (must_remove)
 194                                 unlink(dev);
 195
 196                         if (mknod(dev, S_IFBLK|0600, makedev(major, minor))!= 0) {
 197                                 fprintf(stderr, Name ": failed to create %s\n", dev);
 198                                 return -1;
 199                         }
 200                         if (must_remove) {
 201                                 chown(dev, stb.st_uid, stb.st_gid);
 202                                 chmod(dev, stb.st_mode & 07777);
 203                         }
 204                         make_parts(dev,autof);
 205                 }
 206         }
 207         mdfd = open(dev, O_RDWR, 0);
 208         if (mdfd < 0)
 209                 fprintf(stderr, Name ": error opening %s: %s\n",
 210                         dev, strerror(errno));
 211         else if (md_get_version(mdfd) <= 0) {
 212                 fprintf(stderr, Name ": %s does not appear to be an md device\n",
 213                         dev);
 214                 close(mdfd);
 215                 mdfd = -1;
 216         }
 217         return mdfd;
 218 }
 219