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[PATH_MAX];
  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 /* When we create a new array, we don't want the content to
 167  * be immediately examined by udev - it is probably meaningless.
 168  * So create /run/mdadm/creating-mdXXX and expect that a udev
 169  * rule will noticed this and act accordingly.
 170  */
 171 static char block_path[] = "/run/mdadm/creating-%s";
 172 static char *unblock_path = NULL;
 173 void udev_block(char *devnm)
 174 {
 175         int fd;
 176         char *path = NULL;
 177
 178         xasprintf(&path, block_path, devnm);
 179         fd = open(path, O_CREAT|O_RDWR, 0600);
 180         if (fd >= 0) {
 181                 close(fd);
 182                 unblock_path = path;
 183         } else
 184                 free(path);
 185 }
 186
 187 void udev_unblock(void)
 188 {
 189         if (unblock_path)
 190                 unlink(unblock_path);
 191         free(unblock_path);
 192         unblock_path = NULL;
 193 }
 194
 195 /*
 196  * convert a major/minor pair for a block device into a name in /dev, if possible.
 197  * On the first call, walk /dev collecting name.
 198  * Put them in a simple linked listfor now.
 199  */
 200 struct devmap {
 201         int major, minor;
 202         char *name;
 203         struct devmap *next;
 204 } *devlist = NULL;
 205 int devlist_ready = 0;
 206
 207 int add_dev(const char *name, const struct stat *stb, int flag, struct FTW *s)
 208 {
 209         struct stat st;
 210
 211         if (S_ISLNK(stb->st_mode)) {
 212                 if (stat(name, &st) != 0)
 213                         return 0;
 214                 stb = &st;
 215         }
 216
 217         if ((stb->st_mode&S_IFMT)== S_IFBLK) {
 218                 char *n = xstrdup(name);
 219                 struct devmap *dm = xmalloc(sizeof(*dm));
 220                 if (strncmp(n, "/dev/./", 7) == 0)
 221                         strcpy(n + 4, name + 6);
 222                 if (dm) {
 223                         dm->major = major(stb->st_rdev);
 224                         dm->minor = minor(stb->st_rdev);
 225                         dm->name = n;
 226                         dm->next = devlist;
 227                         devlist = dm;
 228                 }
 229         }
 230
 231         return 0;
 232 }
 233
 234 #ifndef HAVE_NFTW
 235 #ifdef HAVE_FTW
 236 int add_dev_1(const char *name, const struct stat *stb, int flag)
 237 {
 238         return add_dev(name, stb, flag, NULL);
 239 }
 240 int nftw(const char *path,
 241          int (*han)(const char *name, const struct stat *stb,
 242                     int flag, struct FTW *s), int nopenfd, int flags)
 243 {
 244         return ftw(path, add_dev_1, nopenfd);
 245 }
 246 #else
 247 int nftw(const char *path,
 248          int (*han)(const char *name, const struct stat *stb,
 249                     int flag, struct FTW *s), int nopenfd, int flags)
 250 {
 251         return 0;
 252 }
 253 #endif /* HAVE_FTW */
 254 #endif /* HAVE_NFTW */
 255
 256 /*
 257  * Find a block device with the right major/minor number.
 258  * If we find multiple names, choose the shortest.
 259  * If we find a name in /dev/md/, we prefer that.
 260  * This applies only to names for MD devices.
 261  * If 'prefer' is set (normally to e.g. /by-path/)
 262  * then we prefer a name which contains that string.
 263  */
 264 char *map_dev_preferred(int major, int minor, int create,
 265                         char *prefer)
 266 {
 267         struct devmap *p;
 268         char *regular = NULL, *preferred=NULL;
 269         int did_check = 0;
 270
 271         if (major == 0 && minor == 0)
 272                 return NULL;
 273
 274  retry:
 275         if (!devlist_ready) {
 276                 char *dev = "/dev";
 277                 struct stat stb;
 278                 while(devlist) {
 279                         struct devmap *d = devlist;
 280                         devlist = d->next;
 281                         free(d->name);
 282                         free(d);
 283                 }
 284                 if (lstat(dev, &stb) == 0 && S_ISLNK(stb.st_mode))
 285                         dev = "/dev/.";
 286                 nftw(dev, add_dev, 10, FTW_PHYS);
 287                 devlist_ready=1;
 288                 did_check = 1;
 289         }
 290
 291         for (p = devlist; p; p = p->next)
 292                 if (p->major == major && p->minor == minor) {
 293                         if (strncmp(p->name, "/dev/md/",8) == 0 ||
 294                             (prefer && strstr(p->name, prefer))) {
 295                                 if (preferred == NULL ||
 296                                     strlen(p->name) < strlen(preferred))
 297                                         preferred = p->name;
 298                         } else {
 299                                 if (regular == NULL ||
 300                                     strlen(p->name) < strlen(regular))
 301                                         regular = p->name;
 302                         }
 303                 }
 304         if (!regular && !preferred && !did_check) {
 305                 devlist_ready = 0;
 306                 goto retry;
 307         }
 308         if (create && !regular && !preferred) {
 309                 static char buf[30];
 310                 snprintf(buf, sizeof(buf), "%d:%d", major, minor);
 311                 regular = buf;
 312         }
 313
 314         return preferred ? preferred : regular;
 315 }
 316
 317 /* conf_word gets one word from the conf file.
 318  * if "allow_key", then accept words at the start of a line,
 319  * otherwise stop when such a word is found.
 320  * We assume that the file pointer is at the end of a word, so the
 321  * next character is a space, or a newline.  If not, it is the start of a line.
 322  */
 323
 324 char *conf_word(FILE *file, int allow_key)
 325 {
 326         int wsize = 100;
 327         int len = 0;
 328         int c;
 329         int quote;
 330         int wordfound = 0;
 331         char *word = xmalloc(wsize);
 332
 333         while (wordfound == 0) {
 334                 /* at the end of a word.. */
 335                 c = getc(file);
 336                 if (c == '#')
 337                         while (c != EOF && c != '\n')
 338                                 c = getc(file);
 339                 if (c == EOF)
 340                         break;
 341                 if (c == '\n')
 342                         continue;
 343
 344                 if (c != ' ' && c != '\t' && ! allow_key) {
 345                         ungetc(c, file);
 346                         break;
 347                 }
 348                 /* looks like it is safe to get a word here, if there is one */
 349                 quote = 0;
 350                 /* first, skip any spaces */
 351                 while (c == ' ' || c == '\t')
 352                         c = getc(file);
 353                 if (c != EOF && c != '\n' && c != '#') {
 354                         /* we really have a character of a word, so start saving it */
 355                         while (c != EOF && c != '\n' &&
 356                                (quote || (c != ' ' && c != '\t'))) {
 357                                 wordfound = 1;
 358                                 if (quote && c == quote)
 359                                         quote = 0;
 360                                 else if (quote == 0 && (c == '\'' || c == '"'))
 361                                         quote = c;
 362                                 else {
 363                                         if (len == wsize-1) {
 364                                                 wsize += 100;
 365                                                 word = xrealloc(word, wsize);
 366                                         }
 367                                         word[len++] = c;
 368                                 }
 369                                 c = getc(file);
 370                                 /* Hack for broken kernels (2.6.14-.24) that put
 371                                  *        "active(auto-read-only)"
 372                                  * in /proc/mdstat instead of
 373                                  *        "active (auto-read-only)"
 374                                  */
 375                                 if (c == '(' && len >= 6 &&
 376                                     strncmp(word + len - 6, "active", 6) == 0)
 377                                         c = ' ';
 378                         }
 379                 }
 380                 if (c != EOF)
 381                         ungetc(c, file);
 382         }
 383         word[len] = 0;
 384
 385         /* Further HACK for broken kernels.. 2.6.14-2.6.24 */
 386         if (strcmp(word, "auto-read-only)") == 0)
 387                 strcpy(word, "(auto-read-only)");
 388
 389 /*    printf("word is <%s>\n", word); */
 390         if (!wordfound) {
 391                 free(word);
 392                 word = NULL;
 393         }
 394         return word;
 395 }
 396
 397 void print_quoted(char *str)
 398 {
 399         /* Printf the string with surrounding quotes
 400          * iff needed.
 401          * If no space, tab, or quote - leave unchanged.
 402          * Else print surrounded by " or ', swapping quotes
 403          * when we find one that will cause confusion.
 404          */
 405
 406         char first_quote = 0, q;
 407         char *c;
 408
 409         for (c = str; *c; c++) {
 410                 switch(*c) {
 411                 case '\'':
 412                 case '"':
 413                         first_quote = *c;
 414                         break;
 415                 case ' ':
 416                 case '\t':
 417                         first_quote = *c;
 418                         continue;
 419                 default:
 420                         continue;
 421                 }
 422                 break;
 423         }
 424         if (!first_quote) {
 425                 printf("%s", str);
 426                 return;
 427         }
 428
 429         if (first_quote == '"')
 430                 q = '\'';
 431         else
 432                 q = '"';
 433         putchar(q);
 434         for (c = str; *c; c++) {
 435                 if (*c == q) {
 436                         putchar(q);
 437                         q ^= '"' ^ '\'';
 438                         putchar(q);
 439                 }
 440                 putchar(*c);
 441         }
 442         putchar(q);
 443 }
 444
 445 void print_escape(char *str)
 446 {
 447         /* print str, but change space and tab to '_'
 448          * as is suitable for device names
 449          */
 450         for (; *str; str++) {
 451                 switch (*str) {
 452                 case ' ':
 453                 case '\t':
 454                         putchar('_');
 455                         break;
 456                 case '/':
 457                         putchar('-');
 458                         break;
 459                 default:
 460                         putchar(*str);
 461                 }
 462         }
 463 }
 464
 465 int check_env(char *name)
 466 {
 467         char *val = getenv(name);
 468
 469         if (val && atoi(val) == 1)
 470                 return 1;
 471
 472         return 0;
 473 }
 474
 475 int use_udev(void)
 476 {
 477         static int use = -1;
 478         struct stat stb;
 479
 480         if (use < 0) {
 481                 use = ((stat("/dev/.udev", &stb) == 0 ||
 482                         stat("/run/udev", &stb) == 0) &&
 483                        check_env("MDADM_NO_UDEV") == 0);
 484         }
 485         return use;
 486 }
 487
 488 unsigned long GCD(unsigned long a, unsigned long b)
 489 {
 490         while (a != b) {
 491                 if (a < b)
 492                         b -= a;
 493                 if (b < a)
 494                         a -= b;
 495         }
 496         return a;
 497 }
 498
 499 /*
 500  * conf_line reads one logical line from the conffile or mdstat.
 501  * It skips comments and continues until it finds a line that starts
 502  * with a non blank/comment.  This character is pushed back for the next call
 503  * A doubly linked list of words is returned.
 504  * the first word will be a keyword.  Other words will have had quotes removed.
 505  */
 506
 507 char *conf_line(FILE *file)
 508 {
 509         char *w;
 510         char *list;
 511
 512         w = conf_word(file, 1);
 513         if (w == NULL)
 514                 return NULL;
 515
 516         list = dl_strdup(w);
 517         free(w);
 518         dl_init(list);
 519
 520         while ((w = conf_word(file, 0))){
 521                 char *w2 = dl_strdup(w);
 522                 free(w);
 523                 dl_add(list, w2);
 524         }
 525 /*    printf("got a line\n");*/
 526         return list;
 527 }
 528
 529 void free_line(char *line)
 530 {
 531         char *w;
 532         for (w = dl_next(line); w != line; w = dl_next(line)) {
 533                 dl_del(w);
 534                 dl_free(w);
 535         }
 536         dl_free(line);
 537 }