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)==9)
  87                         sprintf(sra->sys_name, "md%d", (int)minor(stb.st_rdev));
  88                 else
  89                         sprintf(sra->sys_name, "md_d%d",
  90                                 (int)minor(stb.st_rdev)>>MdpMinorShift);
  91         } else {
  92                 if (devnum >= 0)
  93                         sprintf(sra->sys_name, "md%d", devnum);
  94                 else
  95                         sprintf(sra->sys_name, "md_d%d",
  96                                 -1-devnum);
  97         }
  98         sprintf(fname, "/sys/block/%s/md/", sra->sys_name);
  99         base = fname + strlen(fname);
 100
 101         sra->devs = NULL;
 102         if (options & GET_VERSION) {
 103                 strcpy(base, "metadata_version");
 104                 if (load_sys(fname, buf))
 105                         goto abort;
 106                 if (strncmp(buf, "none", 4) == 0) {
 107                         sra->array.major_version =
 108                                 sra->array.minor_version = -1;
 109                         strcpy(sra->text_version, "");
 110                 } else if (strncmp(buf, "external:", 9) == 0) {
 111                         sra->array.major_version = -1;
 112                         sra->array.minor_version = -2;
 113                         strcpy(sra->text_version, buf+9);
 114                 } else
 115                         sscanf(buf, "%d.%d",
 116                                &sra->array.major_version,
 117                                &sra->array.minor_version);
 118         }
 119         if (options & GET_LEVEL) {
 120                 strcpy(base, "level");
 121                 if (load_sys(fname, buf))
 122                         goto abort;
 123                 sra->array.level = map_name(pers, buf);
 124         }
 125         if (options & GET_LAYOUT) {
 126                 strcpy(base, "layout");
 127                 if (load_sys(fname, buf))
 128                         goto abort;
 129                 sra->array.layout = strtoul(buf, NULL, 0);
 130         }
 131         if (options & GET_COMPONENT) {
 132                 strcpy(base, "component_size");
 133                 if (load_sys(fname, buf))
 134                         goto abort;
 135                 sra->component_size = strtoull(buf, NULL, 0);
 136                 /* sysfs reports "K", but we want sectors */
 137                 sra->component_size *= 2;
 138         }
 139         if (options & GET_CHUNK) {
 140                 strcpy(base, "chunk_size");
 141                 if (load_sys(fname, buf))
 142                         goto abort;
 143                 sra->array.chunk_size = strtoul(buf, NULL, 0);
 144         }
 145         if (options & GET_CACHE) {
 146                 strcpy(base, "stripe_cache_size");
 147                 if (load_sys(fname, buf))
 148                         goto abort;
 149                 sra->cache_size = strtoul(buf, NULL, 0);
 150         }
 151         if (options & GET_MISMATCH) {
 152                 strcpy(base, "mismatch_cnt");
 153                 if (load_sys(fname, buf))
 154                         goto abort;
 155                 sra->mismatch_cnt = strtoul(buf, NULL, 0);
 156         }
 157
 158         if (! (options & GET_DEVS))
 159                 return sra;
 160
 161         /* Get all the devices as well */
 162         *base = 0;
 163         dir = opendir(fname);
 164         if (!dir)
 165                 goto abort;
 166         sra->array.spare_disks = 0;
 167
 168         while ((de = readdir(dir)) != NULL) {
 169                 char *ep;
 170                 if (de->d_ino == 0 ||
 171                     strncmp(de->d_name, "dev-", 4) != 0)
 172                         continue;
 173                 strcpy(base, de->d_name);
 174                 dbase = base + strlen(base);
 175                 *dbase++ = '/';
 176
 177                 dev = malloc(sizeof(*dev));
 178                 if (!dev)
 179                         goto abort;
 180                 dev->next = sra->devs;
 181                 sra->devs = dev;
 182                 strcpy(dev->sys_name, de->d_name);
 183
 184                 /* Always get slot, major, minor */
 185                 strcpy(dbase, "slot");
 186                 if (load_sys(fname, buf))
 187                         goto abort;
 188                 dev->disk.raid_disk = strtoul(buf, &ep, 10);
 189                 if (*ep) dev->disk.raid_disk = -1;
 190
 191                 strcpy(dbase, "block/dev");
 192                 if (load_sys(fname, buf))
 193                         goto abort;
 194                 sscanf(buf, "%d:%d", &dev->disk.major, &dev->disk.minor);
 195
 196                 if (options & GET_OFFSET) {
 197                         strcpy(dbase, "offset");
 198                         if (load_sys(fname, buf))
 199                                 goto abort;
 200                         dev->data_offset = strtoull(buf, NULL, 0);
 201                 }
 202                 if (options & GET_SIZE) {
 203                         strcpy(dbase, "size");
 204                         if (load_sys(fname, buf))
 205                                 goto abort;
 206                         dev->component_size = strtoull(buf, NULL, 0);
 207                 }
 208                 if (options & GET_STATE) {
 209                         dev->disk.state = 0;
 210                         strcpy(dbase, "state");
 211                         if (load_sys(fname, buf))
 212                                 goto abort;
 213                         if (strstr(buf, "in_sync"))
 214                                 dev->disk.state |= (1<<MD_DISK_SYNC);
 215                         if (strstr(buf, "faulty"))
 216                                 dev->disk.state |= (1<<MD_DISK_FAULTY);
 217                         if (dev->disk.state == 0)
 218                                 sra->array.spare_disks++;
 219                 }
 220                 if (options & GET_ERROR) {
 221                         strcpy(buf, "errors");
 222                         if (load_sys(fname, buf))
 223                                 goto abort;
 224                         dev->errors = strtoul(buf, NULL, 0);
 225                 }
 226         }
 227         return sra;
 228
 229  abort:
 230         sysfs_free(sra);
 231         return NULL;
 232 }
 233
 234 unsigned long long get_component_size(int fd)
 235 {
 236         /* Find out the component size of the array.
 237          * We cannot trust GET_ARRAY_INFO ioctl as it's
 238          * size field is only 32bits.
 239          * So look in /sys/block/mdXXX/md/component_size
 240          *
 241          * This returns in units of sectors.
 242          */
 243         struct stat stb;
 244         char fname[50];
 245         int n;
 246         if (fstat(fd, &stb)) return 0;
 247         if (major(stb.st_rdev) == 9)
 248                 sprintf(fname, "/sys/block/md%d/md/component_size",
 249                         (int)minor(stb.st_rdev));
 250         else
 251                 sprintf(fname, "/sys/block/md_d%d/md/component_size",
 252                         (int)minor(stb.st_rdev)>>MdpMinorShift);
 253         fd = open(fname, O_RDONLY);
 254         if (fd < 0)
 255                 return 0;
 256         n = read(fd, fname, sizeof(fname));
 257         close(fd);
 258         if (n == sizeof(fname))
 259                 return 0;
 260         fname[n] = 0;
 261         return strtoull(fname, NULL, 10) * 2;
 262 }
 263
 264 int sysfs_set_str(struct mdinfo *sra, struct mdinfo *dev,
 265                   char *name, char *val)
 266 {
 267         char fname[50];
 268         int n;
 269         int fd;
 270         sprintf(fname, "/sys/block/%s/md/%s/%s",
 271                 sra->sys_name, dev?dev->sys_name:"", name);
 272         fd = open(fname, O_WRONLY);
 273         if (fd < 0)
 274                 return -1;
 275         n = write(fd, val, strlen(val));
 276         close(fd);
 277         if (n != strlen(val))
 278                 return -1;
 279         return 0;
 280 }
 281
 282 int sysfs_set_num(struct mdinfo *sra, struct mdinfo *dev,
 283                   char *name, unsigned long long val)
 284 {
 285         char valstr[50];
 286         sprintf(valstr, "%llu", val);
 287         return sysfs_set_str(sra, dev, name, valstr);
 288 }
 289
 290 int sysfs_get_ll(struct mdinfo *sra, struct mdinfo *dev,
 291                        char *name, unsigned long long *val)
 292 {
 293         char fname[50];
 294         char buf[50];
 295         int n;
 296         int fd;
 297         char *ep;
 298         sprintf(fname, "/sys/block/%s/md/%s/%s",
 299                 sra->sys_name, dev?dev->sys_name:"", name);
 300         fd = open(fname, O_RDONLY);
 301         if (fd < 0)
 302                 return -1;
 303         n = read(fd, buf, sizeof(buf));
 304         close(fd);
 305         if (n <= 0)
 306                 return -1;
 307         buf[n] = 0;
 308         *val = strtoull(buf, &ep, 0);
 309         if (ep == buf || (*ep != 0 && *ep != '\n' && *ep != ' '))
 310                 return -1;
 311         return 0;
 312 }