sysfs.c

   1 /*
   2  * sysfs - extract md related information from sysfs.  Part of:
   3  * mdadm - manage Linux "md" devices aka RAID arrays.
   4  *
   5  * Copyright (C) 2006 Neil Brown <neilb@suse.de>
   6  *
   7  *
   8  *    This program is free software; you can redistribute it and/or modify
   9  *    it under the terms of the GNU General Public License as published by
  10  *    the Free Software Foundation; either version 2 of the License, or
  11  *    (at your option) any later version.
  12  *
  13  *    This program is distributed in the hope that it will be useful,
  14  *    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  *    GNU General Public License for more details.
  17  *
  18  *    You should have received a copy of the GNU General Public License
  19  *    along with this program; if not, write to the Free Software
  20  *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21  *
  22  *    Author: Neil Brown
  23  *    Email: <neilb@suse.de>
  24  */
  25
  26 #include        "mdadm.h"
  27 #include        <dirent.h>
  28
  29 int load_sys(char *path, char *buf)
  30 {
  31         int fd = open(path, O_RDONLY);
  32         int n;
  33         if (fd < 0)
  34                 return -1;
  35         n = read(fd, buf, 1024);
  36         close(fd);
  37         if (n <=0 || n >= 1024)
  38                 return -1;
  39         buf[n] = 0;
  40         if (buf[n-1] == '\n')
  41                 buf[n-1] = 0;
  42         return 0;
  43 }
  44
  45 void sysfs_free(struct mdinfo *sra)
  46 {
  47         while (sra) {
  48                 struct mdinfo *sra2 = sra->next;
  49                 while (sra->devs) {
  50                         struct mdinfo *d = sra->devs;
  51                         sra->devs = d->next;
  52                         free(d);
  53                 }
  54                 free(sra);
  55                 sra = sra2;
  56         }
  57 }
  58
  59 struct mdinfo *sysfs_read(int fd, int devnum, unsigned long options)
  60 {
  61         /* Longest possible name in sysfs, mounted at /sys, is
  62          *  /sys/block/md_dXXX/md/dev-XXXXX/block/dev
  63          *  /sys/block/md_dXXX/md/metadata_version
  64          * which is about 41 characters.  50 should do for now
  65          */
  66         char fname[50];
  67         char buf[1024];
  68         char *base;
  69         char *dbase;
  70         struct mdinfo *sra;
  71         struct mdinfo *dev;
  72         DIR *dir;
  73         struct dirent *de;
  74
  75         sra = malloc(sizeof(*sra));
  76         if (sra == NULL)
  77                 return sra;
  78         sra->next = NULL;
  79
  80         if (fd >= 0) {
  81                 struct stat stb;
  82                 mdu_version_t vers;
  83                 if (fstat(fd, &stb)) return NULL;
  84                 if (ioctl(fd, RAID_VERSION, &vers) != 0)
  85                         return NULL;
  86                 if (major(stb.st_rdev) == MD_MAJOR)
  87                         sprintf(sra->sys_name, "md%d", (int)minor(stb.st_rdev));
  88                 else if (major(stb.st_rdev) == get_mdp_major())
  89                         sprintf(sra->sys_name, "md_d%d",
  90                                 (int)minor(stb.st_rdev)>>MdpMinorShift);
  91                 else {
  92                         /* must be an extended-minor partition. Look at the
  93                          * /sys/dev/block/%d:%d link which must look like
  94                          * ../../block/mdXXX/mdXXXpYY
  95                          */
  96                         char path[30];
  97                         char link[200];
  98                         char *cp;
  99                         int n;
 100                         sprintf(path, "/sys/dev/block/%d:%d", major(stb.st_rdev),
 101                                 minor(stb.st_rdev));
 102                         n = readlink(path, link, sizeof(link)-1);
 103                         if (n <= 0)
 104                                 return NULL;
 105                         link[n] = 0;
 106                         cp = strrchr(link, '/');
 107                         if (cp) *cp = 0;
 108                         cp = strchr(link, '/');
 109                         if (cp && strncmp(cp, "/md", 3) == 0)
 110                                 strcpy(sra->sys_name, cp+1);
 111                         else
 112                                 return NULL;
 113                 }
 114         } else {
 115                 if (devnum >= 0)
 116                         sprintf(sra->sys_name, "md%d", devnum);
 117                 else
 118                         sprintf(sra->sys_name, "md_d%d",
 119                                 -1-devnum);
 120         }
 121         sprintf(fname, "/sys/block/%s/md/", sra->sys_name);
 122         base = fname + strlen(fname);
 123
 124         sra->devs = NULL;
 125         if (options & GET_VERSION) {
 126                 strcpy(base, "metadata_version");
 127                 if (load_sys(fname, buf))
 128                         goto abort;
 129                 if (strncmp(buf, "none", 4) == 0) {
 130                         sra->array.major_version =
 131                                 sra->array.minor_version = -1;
 132                         strcpy(sra->text_version, "");
 133                 } else if (strncmp(buf, "external:", 9) == 0) {
 134                         sra->array.major_version = -1;
 135                         sra->array.minor_version = -2;
 136                         strcpy(sra->text_version, buf+9);
 137                 } else
 138                         sscanf(buf, "%d.%d",
 139                                &sra->array.major_version,
 140                                &sra->array.minor_version);
 141         }
 142         if (options & GET_LEVEL) {
 143                 strcpy(base, "level");
 144                 if (load_sys(fname, buf))
 145                         goto abort;
 146                 sra->array.level = map_name(pers, buf);
 147         }
 148         if (options & GET_LAYOUT) {
 149                 strcpy(base, "layout");
 150                 if (load_sys(fname, buf))
 151                         goto abort;
 152                 sra->array.layout = strtoul(buf, NULL, 0);
 153         }
 154         if (options & GET_COMPONENT) {
 155                 strcpy(base, "component_size");
 156                 if (load_sys(fname, buf))
 157                         goto abort;
 158                 sra->component_size = strtoull(buf, NULL, 0);
 159                 /* sysfs reports "K", but we want sectors */
 160                 sra->component_size *= 2;
 161         }
 162         if (options & GET_CHUNK) {
 163                 strcpy(base, "chunk_size");
 164                 if (load_sys(fname, buf))
 165                         goto abort;
 166                 sra->array.chunk_size = strtoul(buf, NULL, 0);
 167         }
 168         if (options & GET_CACHE) {
 169                 strcpy(base, "stripe_cache_size");
 170                 if (load_sys(fname, buf))
 171                         goto abort;
 172                 sra->cache_size = strtoul(buf, NULL, 0);
 173         }
 174         if (options & GET_MISMATCH) {
 175                 strcpy(base, "mismatch_cnt");
 176                 if (load_sys(fname, buf))
 177                         goto abort;
 178                 sra->mismatch_cnt = strtoul(buf, NULL, 0);
 179         }
 180
 181         if (! (options & GET_DEVS))
 182                 return sra;
 183
 184         /* Get all the devices as well */
 185         *base = 0;
 186         dir = opendir(fname);
 187         if (!dir)
 188                 goto abort;
 189         sra->array.spare_disks = 0;
 190
 191         while ((de = readdir(dir)) != NULL) {
 192                 char *ep;
 193                 if (de->d_ino == 0 ||
 194                     strncmp(de->d_name, "dev-", 4) != 0)
 195                         continue;
 196                 strcpy(base, de->d_name);
 197                 dbase = base + strlen(base);
 198                 *dbase++ = '/';
 199
 200                 dev = malloc(sizeof(*dev));
 201                 if (!dev)
 202                         goto abort;
 203                 dev->next = sra->devs;
 204                 sra->devs = dev;
 205                 strcpy(dev->sys_name, de->d_name);
 206
 207                 /* Always get slot, major, minor */
 208                 strcpy(dbase, "slot");
 209                 if (load_sys(fname, buf))
 210                         goto abort;
 211                 dev->disk.raid_disk = strtoul(buf, &ep, 10);
 212                 if (*ep) dev->disk.raid_disk = -1;
 213
 214                 strcpy(dbase, "block/dev");
 215                 if (load_sys(fname, buf))
 216                         goto abort;
 217                 sscanf(buf, "%d:%d", &dev->disk.major, &dev->disk.minor);
 218
 219                 if (options & GET_OFFSET) {
 220                         strcpy(dbase, "offset");
 221                         if (load_sys(fname, buf))
 222                                 goto abort;
 223                         dev->data_offset = strtoull(buf, NULL, 0);
 224                 }
 225                 if (options & GET_SIZE) {
 226                         strcpy(dbase, "size");
 227                         if (load_sys(fname, buf))
 228                                 goto abort;
 229                         dev->component_size = strtoull(buf, NULL, 0);
 230                 }
 231                 if (options & GET_STATE) {
 232                         dev->disk.state = 0;
 233                         strcpy(dbase, "state");
 234                         if (load_sys(fname, buf))
 235                                 goto abort;
 236                         if (strstr(buf, "in_sync"))
 237                                 dev->disk.state |= (1<<MD_DISK_SYNC);
 238                         if (strstr(buf, "faulty"))
 239                                 dev->disk.state |= (1<<MD_DISK_FAULTY);
 240                         if (dev->disk.state == 0)
 241                                 sra->array.spare_disks++;
 242                 }
 243                 if (options & GET_ERROR) {
 244                         strcpy(buf, "errors");
 245                         if (load_sys(fname, buf))
 246                                 goto abort;
 247                         dev->errors = strtoul(buf, NULL, 0);
 248                 }
 249         }
 250         return sra;
 251
 252  abort:
 253         sysfs_free(sra);
 254         return NULL;
 255 }
 256
 257 unsigned long long get_component_size(int fd)
 258 {
 259         /* Find out the component size of the array.
 260          * We cannot trust GET_ARRAY_INFO ioctl as it's
 261          * size field is only 32bits.
 262          * So look in /sys/block/mdXXX/md/component_size
 263          *
 264          * This returns in units of sectors.
 265          */
 266         struct stat stb;
 267         char fname[50];
 268         int n;
 269         if (fstat(fd, &stb)) return 0;
 270         if (major(stb.st_rdev) != get_mdp_major())
 271                 sprintf(fname, "/sys/block/md%d/md/component_size",
 272                         (int)minor(stb.st_rdev));
 273         else
 274                 sprintf(fname, "/sys/block/md_d%d/md/component_size",
 275                         (int)minor(stb.st_rdev)>>MdpMinorShift);
 276         fd = open(fname, O_RDONLY);
 277         if (fd < 0)
 278                 return 0;
 279         n = read(fd, fname, sizeof(fname));
 280         close(fd);
 281         if (n == sizeof(fname))
 282                 return 0;
 283         fname[n] = 0;
 284         return strtoull(fname, NULL, 10) * 2;
 285 }
 286
 287 int sysfs_set_str(struct mdinfo *sra, struct mdinfo *dev,
 288                   char *name, char *val)
 289 {
 290         char fname[50];
 291         int n;
 292         int fd;
 293         sprintf(fname, "/sys/block/%s/md/%s/%s",
 294                 sra->sys_name, dev?dev->sys_name:"", name);
 295         fd = open(fname, O_WRONLY);
 296         if (fd < 0)
 297                 return -1;
 298         n = write(fd, val, strlen(val));
 299         close(fd);
 300         if (n != strlen(val))
 301                 return -1;
 302         return 0;
 303 }
 304
 305 int sysfs_set_num(struct mdinfo *sra, struct mdinfo *dev,
 306                   char *name, unsigned long long val)
 307 {
 308         char valstr[50];
 309         sprintf(valstr, "%llu", val);
 310         return sysfs_set_str(sra, dev, name, valstr);
 311 }
 312
 313 int sysfs_get_ll(struct mdinfo *sra, struct mdinfo *dev,
 314                        char *name, unsigned long long *val)
 315 {
 316         char fname[50];
 317         char buf[50];
 318         int n;
 319         int fd;
 320         char *ep;
 321         sprintf(fname, "/sys/block/%s/md/%s/%s",
 322                 sra->sys_name, dev?dev->sys_name:"", name);
 323         fd = open(fname, O_RDONLY);
 324         if (fd < 0)
 325                 return -1;
 326         n = read(fd, buf, sizeof(buf));
 327         close(fd);
 328         if (n <= 0)
 329                 return -1;
 330         buf[n] = 0;
 331         *val = strtoull(buf, &ep, 0);
 332         if (ep == buf || (*ep != 0 && *ep != '\n' && *ep != ' '))
 333                 return -1;
 334         return 0;
 335 }