lib.c

   1 /*
   2  * mdadm - manage Linux "md" devices aka RAID arrays.
   3  *
   4  * Copyright (C) 2011  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@suse.de>
  23  */
  24
  25 #include        "mdadm.h"
  26 #include        "dlink.h"
  27 #include        <ctype.h>
  28
  29 /* This fill contains various 'library' style function.  They
  30  * have no dependency on anything outside this file.
  31  */
  32
  33 int get_mdp_major(void)
  34 {
  35         static int mdp_major = -1;
  36         FILE *fl;
  37         char *w;
  38         int have_block = 0;
  39         int have_devices = 0;
  40         int last_num = -1;
  41
  42         if (mdp_major != -1)
  43                 return mdp_major;
  44
  45         fl = fopen("/proc/devices", "r");
  46         if (!fl)
  47                 return -1;
  48
  49         while ((w = conf_word(fl, 1))) {
  50                 if (have_block && strcmp(w, "devices:") == 0)
  51                         have_devices = 1;
  52                 have_block =  (strcmp(w, "Block") == 0);
  53                 if (isdigit(w[0]))
  54                         last_num = atoi(w);
  55                 if (have_devices && strcmp(w, "mdp") == 0)
  56                         mdp_major = last_num;
  57                 free(w);
  58         }
  59         fclose(fl);
  60
  61         return mdp_major;
  62 }
  63
  64 char *devid2kname(int devid)
  65 {
  66         char path[30];
  67         char link[200];
  68         static char devnm[32];
  69         char *cp;
  70         int n;
  71
  72         /* Look at the
  73          * /sys/dev/block/%d:%d link which must look like
  74          * and take the last component.
  75          */
  76         sprintf(path, "/sys/dev/block/%d:%d", major(devid),
  77                 minor(devid));
  78         n = readlink(path, link, sizeof(link) - 1);
  79         if (n > 0) {
  80                 link[n] = 0;
  81                 cp = strrchr(link, '/');
  82                 if (cp) {
  83                         strcpy(devnm, cp + 1);
  84                         return devnm;
  85                 }
  86         }
  87         return NULL;
  88 }
  89
  90 char *stat2kname(struct stat *st)
  91 {
  92         if ((S_IFMT & st->st_mode) != S_IFBLK)
  93                 return NULL;
  94
  95         return devid2kname(st->st_rdev);
  96 }
  97
  98 char *fd2kname(int fd)
  99 {
 100         struct stat stb;
 101
 102         if (fstat(fd, &stb) == 0)
 103                 return stat2kname(&stb);
 104
 105         return NULL;
 106 }
 107
 108 char *devid2devnm(dev_t devid)
 109 {
 110         char path[30];
 111         char link[200];
 112         static char devnm[32];
 113         char *cp, *ep;
 114         int n;
 115
 116         /* Might be an extended-minor partition or a
 117          * named md device. Look at the
 118          * /sys/dev/block/%d:%d link which must look like
 119          *    ../../block/mdXXX/mdXXXpYY
 120          * or
 121          *    ...../block/md_FOO
 122          */
 123         sprintf(path, "/sys/dev/block/%d:%d", major(devid), minor(devid));
 124         n = readlink(path, link, sizeof(link) - 1);
 125         if (n > 0) {
 126                 link[n] = 0;
 127                 cp = strstr(link, "/block/");
 128                 if (cp) {
 129                         cp += 7;
 130                         ep = strchr(cp, '/');
 131                         if (ep)
 132                                 *ep = 0;
 133                         strcpy(devnm, cp);
 134                         return devnm;
 135                 }
 136         }
 137         if (major(devid) == MD_MAJOR)
 138                 sprintf(devnm,"md%d", minor(devid));
 139         else if (major(devid) == (unsigned)get_mdp_major())
 140                 sprintf(devnm,"md_d%d",
 141                         (minor(devid)>>MdpMinorShift));
 142         else
 143                 return NULL;
 144
 145         return devnm;
 146 }
 147
 148 char *stat2devnm(struct stat *st)
 149 {
 150         if ((S_IFMT & st->st_mode) != S_IFBLK)
 151                 return NULL;
 152
 153         return devid2devnm(st->st_rdev);
 154 }
 155
 156 char *fd2devnm(int fd)
 157 {
 158         struct stat stb;
 159
 160         if (fstat(fd, &stb) == 0)
 161                 return stat2devnm(&stb);
 162
 163         return NULL;
 164 }
 165
 166 /*
 167  * convert a major/minor pair for a block device into a name in /dev, if possible.
 168  * On the first call, walk /dev collecting name.
 169  * Put them in a simple linked listfor now.
 170  */
 171 struct devmap {
 172         int major, minor;
 173         char *name;
 174         struct devmap *next;
 175 } *devlist = NULL;
 176 int devlist_ready = 0;
 177
 178 int add_dev(const char *name, const struct stat *stb, int flag, struct FTW *s)
 179 {
 180         struct stat st;
 181
 182         if (S_ISLNK(stb->st_mode)) {
 183                 if (stat(name, &st) != 0)
 184                         return 0;
 185                 stb = &st;
 186         }
 187
 188         if ((stb->st_mode&S_IFMT)== S_IFBLK) {
 189                 char *n = xstrdup(name);
 190                 struct devmap *dm = xmalloc(sizeof(*dm));
 191                 if (strncmp(n, "/dev/./", 7) == 0)
 192                         strcpy(n + 4, name + 6);
 193                 if (dm) {
 194                         dm->major = major(stb->st_rdev);
 195                         dm->minor = minor(stb->st_rdev);
 196                         dm->name = n;
 197                         dm->next = devlist;
 198                         devlist = dm;
 199                 }
 200         }
 201
 202         return 0;
 203 }
 204
 205 #ifndef HAVE_NFTW
 206 #ifdef HAVE_FTW
 207 int add_dev_1(const char *name, const struct stat *stb, int flag)
 208 {
 209         return add_dev(name, stb, flag, NULL);
 210 }
 211 int nftw(const char *path,
 212          int (*han)(const char *name, const struct stat *stb,
 213                     int flag, struct FTW *s), int nopenfd, int flags)
 214 {
 215         return ftw(path, add_dev_1, nopenfd);
 216 }
 217 #else
 218 int nftw(const char *path,
 219          int (*han)(const char *name, const struct stat *stb,
 220                     int flag, struct FTW *s), int nopenfd, int flags)
 221 {
 222         return 0;
 223 }
 224 #endif /* HAVE_FTW */
 225 #endif /* HAVE_NFTW */
 226
 227 /*
 228  * Find a block device with the right major/minor number.
 229  * If we find multiple names, choose the shortest.
 230  * If we find a name in /dev/md/, we prefer that.
 231  * This applies only to names for MD devices.
 232  * If 'prefer' is set (normally to e.g. /by-path/)
 233  * then we prefer a name which contains that string.
 234  */
 235 char *map_dev_preferred(int major, int minor, int create,
 236                         char *prefer)
 237 {
 238         struct devmap *p;
 239         char *regular = NULL, *preferred=NULL;
 240         int did_check = 0;
 241
 242         if (major == 0 && minor == 0)
 243                 return NULL;
 244
 245  retry:
 246         if (!devlist_ready) {
 247                 char *dev = "/dev";
 248                 struct stat stb;
 249                 while(devlist) {
 250                         struct devmap *d = devlist;
 251                         devlist = d->next;
 252                         free(d->name);
 253                         free(d);
 254                 }
 255                 if (lstat(dev, &stb) == 0 && S_ISLNK(stb.st_mode))
 256                         dev = "/dev/.";
 257                 nftw(dev, add_dev, 10, FTW_PHYS);
 258                 devlist_ready=1;
 259                 did_check = 1;
 260         }
 261
 262         for (p = devlist; p; p = p->next)
 263                 if (p->major == major && p->minor == minor) {
 264                         if (strncmp(p->name, "/dev/md/",8) == 0 ||
 265                             (prefer && strstr(p->name, prefer))) {
 266                                 if (preferred == NULL ||
 267                                     strlen(p->name) < strlen(preferred))
 268                                         preferred = p->name;
 269                         } else {
 270                                 if (regular == NULL ||
 271                                     strlen(p->name) < strlen(regular))
 272                                         regular = p->name;
 273                         }
 274                 }
 275         if (!regular && !preferred && !did_check) {
 276                 devlist_ready = 0;
 277                 goto retry;
 278         }
 279         if (create && !regular && !preferred) {
 280                 static char buf[30];
 281                 snprintf(buf, sizeof(buf), "%d:%d", major, minor);
 282                 regular = buf;
 283         }
 284
 285         return preferred ? preferred : regular;
 286 }
 287
 288 /* conf_word gets one word from the conf file.
 289  * if "allow_key", then accept words at the start of a line,
 290  * otherwise stop when such a word is found.
 291  * We assume that the file pointer is at the end of a word, so the
 292  * next character is a space, or a newline.  If not, it is the start of a line.
 293  */
 294
 295 char *conf_word(FILE *file, int allow_key)
 296 {
 297         int wsize = 100;
 298         int len = 0;
 299         int c;
 300         int quote;
 301         int wordfound = 0;
 302         char *word = xmalloc(wsize);
 303
 304         while (wordfound == 0) {
 305                 /* at the end of a word.. */
 306                 c = getc(file);
 307                 if (c == '#')
 308                         while (c != EOF && c != '\n')
 309                                 c = getc(file);
 310                 if (c == EOF)
 311                         break;
 312                 if (c == '\n')
 313                         continue;
 314
 315                 if (c != ' ' && c != '\t' && ! allow_key) {
 316                         ungetc(c, file);
 317                         break;
 318                 }
 319                 /* looks like it is safe to get a word here, if there is one */
 320                 quote = 0;
 321                 /* first, skip any spaces */
 322                 while (c == ' ' || c == '\t')
 323                         c = getc(file);
 324                 if (c != EOF && c != '\n' && c != '#') {
 325                         /* we really have a character of a word, so start saving it */
 326                         while (c != EOF && c != '\n' &&
 327                                (quote || (c != ' ' && c != '\t'))) {
 328                                 wordfound = 1;
 329                                 if (quote && c == quote)
 330                                         quote = 0;
 331                                 else if (quote == 0 && (c == '\'' || c == '"'))
 332                                         quote = c;
 333                                 else {
 334                                         if (len == wsize-1) {
 335                                                 wsize += 100;
 336                                                 word = xrealloc(word, wsize);
 337                                         }
 338                                         word[len++] = c;
 339                                 }
 340                                 c = getc(file);
 341                                 /* Hack for broken kernels (2.6.14-.24) that put
 342                                  *        "active(auto-read-only)"
 343                                  * in /proc/mdstat instead of
 344                                  *        "active (auto-read-only)"
 345                                  */
 346                                 if (c == '(' && len >= 6 &&
 347                                     strncmp(word + len - 6, "active", 6) == 0)
 348                                         c = ' ';
 349                         }
 350                 }
 351                 if (c != EOF)
 352                         ungetc(c, file);
 353         }
 354         word[len] = 0;
 355
 356         /* Further HACK for broken kernels.. 2.6.14-2.6.24 */
 357         if (strcmp(word, "auto-read-only)") == 0)
 358                 strcpy(word, "(auto-read-only)");
 359
 360 /*    printf("word is <%s>\n", word); */
 361         if (!wordfound) {
 362                 free(word);
 363                 word = NULL;
 364         }
 365         return word;
 366 }
 367
 368 void print_quoted(char *str)
 369 {
 370         /* Printf the string with surrounding quotes
 371          * iff needed.
 372          * If no space, tab, or quote - leave unchanged.
 373          * Else print surrounded by " or ', swapping quotes
 374          * when we find one that will cause confusion.
 375          */
 376
 377         char first_quote = 0, q;
 378         char *c;
 379
 380         for (c = str; *c; c++) {
 381                 switch(*c) {
 382                 case '\'':
 383                 case '"':
 384                         first_quote = *c;
 385                         break;
 386                 case ' ':
 387                 case '\t':
 388                         first_quote = *c;
 389                         continue;
 390                 default:
 391                         continue;
 392                 }
 393                 break;
 394         }
 395         if (!first_quote) {
 396                 printf("%s", str);
 397                 return;
 398         }
 399
 400         if (first_quote == '"')
 401                 q = '\'';
 402         else
 403                 q = '"';
 404         putchar(q);
 405         for (c = str; *c; c++) {
 406                 if (*c == q) {
 407                         putchar(q);
 408                         q ^= '"' ^ '\'';
 409                         putchar(q);
 410                 }
 411                 putchar(*c);
 412         }
 413         putchar(q);
 414 }
 415
 416 void print_escape(char *str)
 417 {
 418         /* print str, but change space and tab to '_'
 419          * as is suitable for device names
 420          */
 421         for (; *str; str++) {
 422                 switch (*str) {
 423                 case ' ':
 424                 case '\t':
 425                         putchar('_');
 426                         break;
 427                 case '/':
 428                         putchar('-');
 429                         break;
 430                 default:
 431                         putchar(*str);
 432                 }
 433         }
 434 }
 435
 436 int check_env(char *name)
 437 {
 438         char *val = getenv(name);
 439
 440         if (val && atoi(val) == 1)
 441                 return 1;
 442
 443         return 0;
 444 }
 445
 446 int use_udev(void)
 447 {
 448         static int use = -1;
 449         struct stat stb;
 450
 451         if (use < 0) {
 452                 use = ((stat("/dev/.udev", &stb) == 0 ||
 453                         stat("/run/udev", &stb) == 0) &&
 454                        check_env("MDADM_NO_UDEV") == 0);
 455         }
 456         return use;
 457 }
 458
 459 unsigned long GCD(unsigned long a, unsigned long b)
 460 {
 461         while (a != b) {
 462                 if (a < b)
 463                         b -= a;
 464                 if (b < a)
 465                         a -= b;
 466         }
 467         return a;
 468 }
 469
 470 /*
 471  * conf_line reads one logical line from the conffile or mdstat.
 472  * It skips comments and continues until it finds a line that starts
 473  * with a non blank/comment.  This character is pushed back for the next call
 474  * A doubly linked list of words is returned.
 475  * the first word will be a keyword.  Other words will have had quotes removed.
 476  */
 477
 478 char *conf_line(FILE *file)
 479 {
 480         char *w;
 481         char *list;
 482
 483         w = conf_word(file, 1);
 484         if (w == NULL)
 485                 return NULL;
 486
 487         list = dl_strdup(w);
 488         free(w);
 489         dl_init(list);
 490
 491         while ((w = conf_word(file, 0))){
 492                 char *w2 = dl_strdup(w);
 493                 free(w);
 494                 dl_add(list, w2);
 495         }
 496 /*    printf("got a line\n");*/
 497         return list;
 498 }
 499
 500 void free_line(char *line)
 501 {
 502         char *w;
 503         for (w = dl_next(line); w != line; w = dl_next(line)) {
 504                 dl_del(w);
 505                 dl_free(w);
 506         }
 507         dl_free(line);
 508 }