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(dev_t 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), minor(devid));
  77         n = readlink(path, link, sizeof(link) - 1);
  78         if (n > 0) {
  79                 link[n] = 0;
  80                 cp = strrchr(link, '/');
  81                 if (cp) {
  82                         strcpy(devnm, cp + 1);
  83                         return devnm;
  84                 }
  85         }
  86         return NULL;
  87 }
  88
  89 char *stat2kname(struct stat *st)
  90 {
  91         if ((S_IFMT & st->st_mode) != S_IFBLK)
  92                 return NULL;
  93
  94         return devid2kname(st->st_rdev);
  95 }
  96
  97 char *fd2kname(int fd)
  98 {
  99         struct stat stb;
 100
 101         if (fstat(fd, &stb) == 0)
 102                 return stat2kname(&stb);
 103
 104         return NULL;
 105 }
 106
 107 char *devid2devnm(dev_t devid)
 108 {
 109         char path[30];
 110         char link[200];
 111         static char devnm[32];
 112         char *cp, *ep;
 113         int n;
 114
 115         /* Might be an extended-minor partition or a
 116          * named md device. Look at the
 117          * /sys/dev/block/%d:%d link which must look like
 118          *    ../../block/mdXXX/mdXXXpYY
 119          * or
 120          *    ...../block/md_FOO
 121          */
 122         sprintf(path, "/sys/dev/block/%d:%d", major(devid), minor(devid));
 123         n = readlink(path, link, sizeof(link) - 1);
 124         if (n > 0) {
 125                 link[n] = 0;
 126                 cp = strstr(link, "/block/");
 127                 if (cp) {
 128                         cp += 7;
 129                         ep = strchr(cp, '/');
 130                         if (ep)
 131                                 *ep = 0;
 132                         strcpy(devnm, cp);
 133                         return devnm;
 134                 }
 135         }
 136         if (major(devid) == MD_MAJOR)
 137                 sprintf(devnm,"md%d", minor(devid));
 138         else if (major(devid) == (unsigned)get_mdp_major())
 139                 sprintf(devnm,"md_d%d",
 140                         (minor(devid)>>MdpMinorShift));
 141         else
 142                 return NULL;
 143
 144         return devnm;
 145 }
 146
 147 char *stat2devnm(struct stat *st)
 148 {
 149         if ((S_IFMT & st->st_mode) != S_IFBLK)
 150                 return NULL;
 151
 152         return devid2devnm(st->st_rdev);
 153 }
 154
 155 char *fd2devnm(int fd)
 156 {
 157         struct stat stb;
 158
 159         if (fstat(fd, &stb) == 0)
 160                 return stat2devnm(&stb);
 161
 162         return NULL;
 163 }
 164
 165 /* When we create a new array, we don't want the content to
 166  * be immediately examined by udev - it is probably meaningless.
 167  * So create /run/mdadm/creating-mdXXX and expect that a udev
 168  * rule will noticed this and act accordingly.
 169  */
 170 static char block_path[] = "/run/mdadm/creating-%s";
 171 static char *unblock_path = NULL;
 172 void udev_block(char *devnm)
 173 {
 174         int fd;
 175         char *path = NULL;
 176
 177         xasprintf(&path, block_path, devnm);
 178         fd = open(path, O_CREAT|O_RDWR, 0600);
 179         if (fd >= 0) {
 180                 close(fd);
 181                 unblock_path = path;
 182         } else
 183                 free(path);
 184 }
 185
 186 void udev_unblock(void)
 187 {
 188         if (unblock_path)
 189                 unlink(unblock_path);
 190         free(unblock_path);
 191         unblock_path = NULL;
 192 }
 193
 194 /*
 195  * convert a major/minor pair for a block device into a name in /dev, if possible.
 196  * On the first call, walk /dev collecting name.
 197  * Put them in a simple linked listfor now.
 198  */
 199 struct devmap {
 200         int major, minor;
 201         char *name;
 202         struct devmap *next;
 203 } *devlist = NULL;
 204 int devlist_ready = 0;
 205
 206 int add_dev(const char *name, const struct stat *stb, int flag, struct FTW *s)
 207 {
 208         struct stat st;
 209
 210         if (S_ISLNK(stb->st_mode)) {
 211                 if (stat(name, &st) != 0)
 212                         return 0;
 213                 stb = &st;
 214         }
 215
 216         if ((stb->st_mode&S_IFMT)== S_IFBLK) {
 217                 char *n = xstrdup(name);
 218                 struct devmap *dm = xmalloc(sizeof(*dm));
 219                 if (strncmp(n, "/dev/./", 7) == 0)
 220                         strcpy(n + 4, name + 6);
 221                 if (dm) {
 222                         dm->major = major(stb->st_rdev);
 223                         dm->minor = minor(stb->st_rdev);
 224                         dm->name = n;
 225                         dm->next = devlist;
 226                         devlist = dm;
 227                 }
 228         }
 229
 230         return 0;
 231 }
 232
 233 #ifndef HAVE_NFTW
 234 #ifdef HAVE_FTW
 235 int add_dev_1(const char *name, const struct stat *stb, int flag)
 236 {
 237         return add_dev(name, stb, flag, NULL);
 238 }
 239 int nftw(const char *path,
 240          int (*han)(const char *name, const struct stat *stb,
 241                     int flag, struct FTW *s), int nopenfd, int flags)
 242 {
 243         return ftw(path, add_dev_1, nopenfd);
 244 }
 245 #else
 246 int nftw(const char *path,
 247          int (*han)(const char *name, const struct stat *stb,
 248                     int flag, struct FTW *s), int nopenfd, int flags)
 249 {
 250         return 0;
 251 }
 252 #endif /* HAVE_FTW */
 253 #endif /* HAVE_NFTW */
 254
 255 /*
 256  * Find a block device with the right major/minor number.
 257  * If we find multiple names, choose the shortest.
 258  * If we find a name in /dev/md/, we prefer that.
 259  * This applies only to names for MD devices.
 260  * If 'prefer' is set (normally to e.g. /by-path/)
 261  * then we prefer a name which contains that string.
 262  */
 263 char *map_dev_preferred(int major, int minor, int create,
 264                         char *prefer)
 265 {
 266         struct devmap *p;
 267         char *regular = NULL, *preferred=NULL;
 268         int did_check = 0;
 269
 270         if (major == 0 && minor == 0)
 271                 return NULL;
 272
 273  retry:
 274         if (!devlist_ready) {
 275                 char *dev = "/dev";
 276                 struct stat stb;
 277                 while(devlist) {
 278                         struct devmap *d = devlist;
 279                         devlist = d->next;
 280                         free(d->name);
 281                         free(d);
 282                 }
 283                 if (lstat(dev, &stb) == 0 && S_ISLNK(stb.st_mode))
 284                         dev = "/dev/.";
 285                 nftw(dev, add_dev, 10, FTW_PHYS);
 286                 devlist_ready=1;
 287                 did_check = 1;
 288         }
 289
 290         for (p = devlist; p; p = p->next)
 291                 if (p->major == major && p->minor == minor) {
 292                         if (strncmp(p->name, "/dev/md/",8) == 0 ||
 293                             (prefer && strstr(p->name, prefer))) {
 294                                 if (preferred == NULL ||
 295                                     strlen(p->name) < strlen(preferred))
 296                                         preferred = p->name;
 297                         } else {
 298                                 if (regular == NULL ||
 299                                     strlen(p->name) < strlen(regular))
 300                                         regular = p->name;
 301                         }
 302                 }
 303         if (!regular && !preferred && !did_check) {
 304                 devlist_ready = 0;
 305                 goto retry;
 306         }
 307         if (create && !regular && !preferred) {
 308                 static char buf[30];
 309                 snprintf(buf, sizeof(buf), "%d:%d", major, minor);
 310                 regular = buf;
 311         }
 312
 313         return preferred ? preferred : regular;
 314 }
 315
 316 /* conf_word gets one word from the conf file.
 317  * if "allow_key", then accept words at the start of a line,
 318  * otherwise stop when such a word is found.
 319  * We assume that the file pointer is at the end of a word, so the
 320  * next character is a space, or a newline.  If not, it is the start of a line.
 321  */
 322
 323 char *conf_word(FILE *file, int allow_key)
 324 {
 325         int wsize = 100;
 326         int len = 0;
 327         int c;
 328         int quote;
 329         int wordfound = 0;
 330         char *word = xmalloc(wsize);
 331
 332         while (wordfound == 0) {
 333                 /* at the end of a word.. */
 334                 c = getc(file);
 335                 if (c == '#')
 336                         while (c != EOF && c != '\n')
 337                                 c = getc(file);
 338                 if (c == EOF)
 339                         break;
 340                 if (c == '\n')
 341                         continue;
 342
 343                 if (c != ' ' && c != '\t' && ! allow_key) {
 344                         ungetc(c, file);
 345                         break;
 346                 }
 347                 /* looks like it is safe to get a word here, if there is one */
 348                 quote = 0;
 349                 /* first, skip any spaces */
 350                 while (c == ' ' || c == '\t')
 351                         c = getc(file);
 352                 if (c != EOF && c != '\n' && c != '#') {
 353                         /* we really have a character of a word, so start saving it */
 354                         while (c != EOF && c != '\n' &&
 355                                (quote || (c != ' ' && c != '\t'))) {
 356                                 wordfound = 1;
 357                                 if (quote && c == quote)
 358                                         quote = 0;
 359                                 else if (quote == 0 && (c == '\'' || c == '"'))
 360                                         quote = c;
 361                                 else {
 362                                         if (len == wsize-1) {
 363                                                 wsize += 100;
 364                                                 word = xrealloc(word, wsize);
 365                                         }
 366                                         word[len++] = c;
 367                                 }
 368                                 c = getc(file);
 369                                 /* Hack for broken kernels (2.6.14-.24) that put
 370                                  *        "active(auto-read-only)"
 371                                  * in /proc/mdstat instead of
 372                                  *        "active (auto-read-only)"
 373                                  */
 374                                 if (c == '(' && len >= 6 &&
 375                                     strncmp(word + len - 6, "active", 6) == 0)
 376                                         c = ' ';
 377                         }
 378                 }
 379                 if (c != EOF)
 380                         ungetc(c, file);
 381         }
 382         word[len] = 0;
 383
 384         /* Further HACK for broken kernels.. 2.6.14-2.6.24 */
 385         if (strcmp(word, "auto-read-only)") == 0)
 386                 strcpy(word, "(auto-read-only)");
 387
 388 /*    printf("word is <%s>\n", word); */
 389         if (!wordfound) {
 390                 free(word);
 391                 word = NULL;
 392         }
 393         return word;
 394 }
 395
 396 void print_quoted(char *str)
 397 {
 398         /* Printf the string with surrounding quotes
 399          * iff needed.
 400          * If no space, tab, or quote - leave unchanged.
 401          * Else print surrounded by " or ', swapping quotes
 402          * when we find one that will cause confusion.
 403          */
 404
 405         char first_quote = 0, q;
 406         char *c;
 407
 408         for (c = str; *c; c++) {
 409                 switch(*c) {
 410                 case '\'':
 411                 case '"':
 412                         first_quote = *c;
 413                         break;
 414                 case ' ':
 415                 case '\t':
 416                         first_quote = *c;
 417                         continue;
 418                 default:
 419                         continue;
 420                 }
 421                 break;
 422         }
 423         if (!first_quote) {
 424                 printf("%s", str);
 425                 return;
 426         }
 427
 428         if (first_quote == '"')
 429                 q = '\'';
 430         else
 431                 q = '"';
 432         putchar(q);
 433         for (c = str; *c; c++) {
 434                 if (*c == q) {
 435                         putchar(q);
 436                         q ^= '"' ^ '\'';
 437                         putchar(q);
 438                 }
 439                 putchar(*c);
 440         }
 441         putchar(q);
 442 }
 443
 444 void print_escape(char *str)
 445 {
 446         /* print str, but change space and tab to '_'
 447          * as is suitable for device names
 448          */
 449         for (; *str; str++) {
 450                 switch (*str) {
 451                 case ' ':
 452                 case '\t':
 453                         putchar('_');
 454                         break;
 455                 case '/':
 456                         putchar('-');
 457                         break;
 458                 default:
 459                         putchar(*str);
 460                 }
 461         }
 462 }
 463
 464 int check_env(char *name)
 465 {
 466         char *val = getenv(name);
 467
 468         if (val && atoi(val) == 1)
 469                 return 1;
 470
 471         return 0;
 472 }
 473
 474 int use_udev(void)
 475 {
 476         static int use = -1;
 477         struct stat stb;
 478
 479         if (use < 0) {
 480                 use = ((stat("/dev/.udev", &stb) == 0 ||
 481                         stat("/run/udev", &stb) == 0) &&
 482                        check_env("MDADM_NO_UDEV") == 0);
 483         }
 484         return use;
 485 }
 486
 487 unsigned long GCD(unsigned long a, unsigned long b)
 488 {
 489         while (a != b) {
 490                 if (a < b)
 491                         b -= a;
 492                 if (b < a)
 493                         a -= b;
 494         }
 495         return a;
 496 }
 497
 498 /*
 499  * conf_line reads one logical line from the conffile or mdstat.
 500  * It skips comments and continues until it finds a line that starts
 501  * with a non blank/comment.  This character is pushed back for the next call
 502  * A doubly linked list of words is returned.
 503  * the first word will be a keyword.  Other words will have had quotes removed.
 504  */
 505
 506 char *conf_line(FILE *file)
 507 {
 508         char *w;
 509         char *list;
 510
 511         w = conf_word(file, 1);
 512         if (w == NULL)
 513                 return NULL;
 514
 515         list = dl_strdup(w);
 516         free(w);
 517         dl_init(list);
 518
 519         while ((w = conf_word(file, 0))){
 520                 char *w2 = dl_strdup(w);
 521                 free(w);
 522                 dl_add(list, w2);
 523         }
 524 /*    printf("got a line\n");*/
 525         return list;
 526 }
 527
 528 void free_line(char *line)
 529 {
 530         char *w;
 531         for (w = dl_next(line); w != line; w = dl_next(line)) {
 532                 dl_del(w);
 533                 dl_free(w);
 534         }
 535         dl_free(line);
 536 }