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 #include        <limits.h>
  29
  30 bool is_dev_alive(char *path)
  31 {
  32         if (!path)
  33                 return false;
  34
  35         if (access(path, R_OK) == 0)
  36                 return true;
  37
  38         return false;
  39 }
  40
  41 /* This fill contains various 'library' style function.  They
  42  * have no dependency on anything outside this file.
  43  */
  44
  45 int get_mdp_major(void)
  46 {
  47         static int mdp_major = -1;
  48         FILE *fl;
  49         char *w;
  50         int have_block = 0;
  51         int have_devices = 0;
  52         int last_num = -1;
  53
  54         if (mdp_major != -1)
  55                 return mdp_major;
  56
  57         fl = fopen("/proc/devices", "r");
  58         if (!fl)
  59                 return -1;
  60
  61         while ((w = conf_word(fl, 1))) {
  62                 if (have_block && strcmp(w, "devices:") == 0)
  63                         have_devices = 1;
  64                 have_block =  (strcmp(w, "Block") == 0);
  65                 if (isdigit(w[0]))
  66                         last_num = atoi(w);
  67                 if (have_devices && strcmp(w, "mdp") == 0)
  68                         mdp_major = last_num;
  69                 free(w);
  70         }
  71         fclose(fl);
  72
  73         return mdp_major;
  74 }
  75
  76 char *devid2kname(dev_t devid)
  77 {
  78         char path[30];
  79         char link[PATH_MAX];
  80         static char devnm[32];
  81         char *cp;
  82         int n;
  83
  84         /* Look at the
  85          * /sys/dev/block/%d:%d link which must look like
  86          * and take the last component.
  87          */
  88         sprintf(path, "/sys/dev/block/%d:%d", major(devid), minor(devid));
  89         n = readlink(path, link, sizeof(link) - 1);
  90         if (n > 0) {
  91                 link[n] = 0;
  92                 cp = strrchr(link, '/');
  93                 if (cp) {
  94                         strcpy(devnm, cp + 1);
  95                         return devnm;
  96                 }
  97         }
  98         return NULL;
  99 }
 100
 101 char *stat2kname(struct stat *st)
 102 {
 103         if ((S_IFMT & st->st_mode) != S_IFBLK)
 104                 return NULL;
 105
 106         return devid2kname(st->st_rdev);
 107 }
 108
 109 char *fd2kname(int fd)
 110 {
 111         struct stat stb;
 112
 113         if (fstat(fd, &stb) == 0)
 114                 return stat2kname(&stb);
 115
 116         return NULL;
 117 }
 118
 119 char *devid2devnm(dev_t devid)
 120 {
 121         char path[30];
 122         char link[200];
 123         static char devnm[32];
 124         char *cp, *ep;
 125         int n;
 126
 127         /* Might be an extended-minor partition or a
 128          * named md device. Look at the
 129          * /sys/dev/block/%d:%d link which must look like
 130          *    ../../block/mdXXX/mdXXXpYY
 131          * or
 132          *    ...../block/md_FOO
 133          */
 134         sprintf(path, "/sys/dev/block/%d:%d", major(devid), minor(devid));
 135         n = readlink(path, link, sizeof(link) - 1);
 136         if (n > 0) {
 137                 link[n] = 0;
 138                 cp = strstr(link, "/block/");
 139                 if (cp) {
 140                         cp += 7;
 141                         ep = strchr(cp, '/');
 142                         if (ep)
 143                                 *ep = 0;
 144                         strcpy(devnm, cp);
 145                         return devnm;
 146                 }
 147         }
 148         if (major(devid) == MD_MAJOR)
 149                 sprintf(devnm,"md%d", minor(devid));
 150         else if (major(devid) == (unsigned)get_mdp_major())
 151                 sprintf(devnm,"md_d%d",
 152                         (minor(devid)>>MdpMinorShift));
 153         else
 154                 return NULL;
 155
 156         return devnm;
 157 }
 158
 159 char *stat2devnm(struct stat *st)
 160 {
 161         if ((S_IFMT & st->st_mode) != S_IFBLK)
 162                 return NULL;
 163
 164         return devid2devnm(st->st_rdev);
 165 }
 166
 167 bool stat_is_md_dev(struct stat *st)
 168 {
 169         if ((S_IFMT & st->st_mode) != S_IFBLK)
 170                 return false;
 171         if (major(st->st_rdev) == MD_MAJOR)
 172                 return true;
 173         if (major(st->st_rdev) == (unsigned)get_mdp_major())
 174                 return true;
 175
 176         return false;
 177 }
 178
 179 char *fd2devnm(int fd)
 180 {
 181         struct stat stb;
 182
 183         if (fstat(fd, &stb) == 0)
 184                 return stat2devnm(&stb);
 185
 186         return NULL;
 187 }
 188
 189 /* When we create a new array, we don't want the content to
 190  * be immediately examined by udev - it is probably meaningless.
 191  * So create /run/mdadm/creating-mdXXX and expect that a udev
 192  * rule will noticed this and act accordingly.
 193  */
 194 static char block_path[] = "/run/mdadm/creating-%s";
 195 static char *unblock_path = NULL;
 196 void udev_block(char *devnm)
 197 {
 198         int fd;
 199         char *path = NULL;
 200
 201         xasprintf(&path, block_path, devnm);
 202         fd = open(path, O_CREAT|O_RDWR, 0600);
 203         if (fd >= 0) {
 204                 close(fd);
 205                 unblock_path = path;
 206         } else
 207                 free(path);
 208 }
 209
 210 void udev_unblock(void)
 211 {
 212         if (unblock_path)
 213                 unlink(unblock_path);
 214         free(unblock_path);
 215         unblock_path = NULL;
 216 }
 217
 218 /*
 219  * convert a major/minor pair for a block device into a name in /dev, if possible.
 220  * On the first call, walk /dev collecting name.
 221  * Put them in a simple linked listfor now.
 222  */
 223 struct devmap {
 224         int major, minor;
 225         char *name;
 226         struct devmap *next;
 227 } *devlist = NULL;
 228 int devlist_ready = 0;
 229
 230 int add_dev(const char *name, const struct stat *stb, int flag, struct FTW *s)
 231 {
 232         struct stat st;
 233
 234         if (S_ISLNK(stb->st_mode)) {
 235                 if (stat(name, &st) != 0)
 236                         return 0;
 237                 stb = &st;
 238         }
 239
 240         if ((stb->st_mode&S_IFMT)== S_IFBLK) {
 241                 char *n = xstrdup(name);
 242                 struct devmap *dm = xmalloc(sizeof(*dm));
 243                 if (strncmp(n, "/dev/./", 7) == 0)
 244                         strcpy(n + 4, name + 6);
 245                 if (dm) {
 246                         dm->major = major(stb->st_rdev);
 247                         dm->minor = minor(stb->st_rdev);
 248                         dm->name = n;
 249                         dm->next = devlist;
 250                         devlist = dm;
 251                 }
 252         }
 253
 254         return 0;
 255 }
 256
 257 #ifndef HAVE_NFTW
 258 #ifdef HAVE_FTW
 259 int add_dev_1(const char *name, const struct stat *stb, int flag)
 260 {
 261         return add_dev(name, stb, flag, NULL);
 262 }
 263 int nftw(const char *path,
 264          int (*han)(const char *name, const struct stat *stb,
 265                     int flag, struct FTW *s), int nopenfd, int flags)
 266 {
 267         return ftw(path, add_dev_1, nopenfd);
 268 }
 269 #else
 270 int nftw(const char *path,
 271          int (*han)(const char *name, const struct stat *stb,
 272                     int flag, struct FTW *s), int nopenfd, int flags)
 273 {
 274         return 0;
 275 }
 276 #endif /* HAVE_FTW */
 277 #endif /* HAVE_NFTW */
 278
 279 /*
 280  * Find a block device with the right major/minor number.
 281  * If we find multiple names, choose the shortest.
 282  * If we find a name in /dev/md/, we prefer that.
 283  * This applies only to names for MD devices.
 284  * If 'prefer' is set (normally to e.g. /by-path/)
 285  * then we prefer a name which contains that string.
 286  */
 287 char *map_dev_preferred(int major, int minor, int create,
 288                         char *prefer)
 289 {
 290         struct devmap *p;
 291         char *regular = NULL, *preferred=NULL;
 292         int did_check = 0;
 293
 294         if (major == 0 && minor == 0)
 295                 return NULL;
 296
 297  retry:
 298         if (!devlist_ready) {
 299                 char *dev = "/dev";
 300                 struct stat stb;
 301                 while(devlist) {
 302                         struct devmap *d = devlist;
 303                         devlist = d->next;
 304                         free(d->name);
 305                         free(d);
 306                 }
 307                 if (lstat(dev, &stb) == 0 && S_ISLNK(stb.st_mode))
 308                         dev = "/dev/.";
 309                 nftw(dev, add_dev, 10, FTW_PHYS);
 310                 devlist_ready=1;
 311                 did_check = 1;
 312         }
 313
 314         for (p = devlist; p; p = p->next)
 315                 if (p->major == major && p->minor == minor) {
 316                         if (strncmp(p->name, "/dev/md/",8) == 0 ||
 317                             (prefer && strstr(p->name, prefer))) {
 318                                 if (preferred == NULL ||
 319                                     strlen(p->name) < strlen(preferred))
 320                                         preferred = p->name;
 321                         } else {
 322                                 if (regular == NULL ||
 323                                     strlen(p->name) < strlen(regular))
 324                                         regular = p->name;
 325                         }
 326                 }
 327         if (!regular && !preferred && !did_check) {
 328                 devlist_ready = 0;
 329                 goto retry;
 330         }
 331         if (create && !regular && !preferred) {
 332                 static char buf[30];
 333                 snprintf(buf, sizeof(buf), "%d:%d", major, minor);
 334                 regular = buf;
 335         }
 336
 337         return preferred ? preferred : regular;
 338 }
 339
 340 /* conf_word gets one word from the conf file.
 341  * if "allow_key", then accept words at the start of a line,
 342  * otherwise stop when such a word is found.
 343  * We assume that the file pointer is at the end of a word, so the
 344  * next character is a space, or a newline.  If not, it is the start of a line.
 345  */
 346
 347 char *conf_word(FILE *file, int allow_key)
 348 {
 349         int wsize = 100;
 350         int len = 0;
 351         int c;
 352         int quote;
 353         int wordfound = 0;
 354         char *word = xmalloc(wsize);
 355
 356         while (wordfound == 0) {
 357                 /* at the end of a word.. */
 358                 c = getc(file);
 359                 if (c == '#')
 360                         while (c != EOF && c != '\n')
 361                                 c = getc(file);
 362                 if (c == EOF)
 363                         break;
 364                 if (c == '\n')
 365                         continue;
 366
 367                 if (c != ' ' && c != '\t' && ! allow_key) {
 368                         ungetc(c, file);
 369                         break;
 370                 }
 371                 /* looks like it is safe to get a word here, if there is one */
 372                 quote = 0;
 373                 /* first, skip any spaces */
 374                 while (c == ' ' || c == '\t')
 375                         c = getc(file);
 376                 if (c != EOF && c != '\n' && c != '#') {
 377                         /* we really have a character of a word, so start saving it */
 378                         while (c != EOF && c != '\n' &&
 379                                (quote || (c != ' ' && c != '\t'))) {
 380                                 wordfound = 1;
 381                                 if (quote && c == quote)
 382                                         quote = 0;
 383                                 else if (quote == 0 && (c == '\'' || c == '"'))
 384                                         quote = c;
 385                                 else {
 386                                         if (len == wsize-1) {
 387                                                 wsize += 100;
 388                                                 word = xrealloc(word, wsize);
 389                                         }
 390                                         word[len++] = c;
 391                                 }
 392                                 c = getc(file);
 393                                 /* Hack for broken kernels (2.6.14-.24) that put
 394                                  *        "active(auto-read-only)"
 395                                  * in /proc/mdstat instead of
 396                                  *        "active (auto-read-only)"
 397                                  */
 398                                 if (c == '(' && len >= 6 &&
 399                                     strncmp(word + len - 6, "active", 6) == 0)
 400                                         c = ' ';
 401                         }
 402                 }
 403                 if (c != EOF)
 404                         ungetc(c, file);
 405         }
 406         word[len] = 0;
 407
 408         /* Further HACK for broken kernels.. 2.6.14-2.6.24 */
 409         if (strcmp(word, "auto-read-only)") == 0)
 410                 strcpy(word, "(auto-read-only)");
 411
 412 /*    printf("word is <%s>\n", word); */
 413         if (!wordfound) {
 414                 free(word);
 415                 word = NULL;
 416         }
 417         return word;
 418 }
 419
 420 void print_quoted(char *str)
 421 {
 422         /* Printf the string with surrounding quotes
 423          * iff needed.
 424          * If no space, tab, or quote - leave unchanged.
 425          * Else print surrounded by " or ', swapping quotes
 426          * when we find one that will cause confusion.
 427          */
 428
 429         char first_quote = 0, q;
 430         char *c;
 431
 432         for (c = str; *c; c++) {
 433                 switch(*c) {
 434                 case '\'':
 435                 case '"':
 436                         first_quote = *c;
 437                         break;
 438                 case ' ':
 439                 case '\t':
 440                         first_quote = *c;
 441                         continue;
 442                 default:
 443                         continue;
 444                 }
 445                 break;
 446         }
 447         if (!first_quote) {
 448                 printf("%s", str);
 449                 return;
 450         }
 451
 452         if (first_quote == '"')
 453                 q = '\'';
 454         else
 455                 q = '"';
 456         putchar(q);
 457         for (c = str; *c; c++) {
 458                 if (*c == q) {
 459                         putchar(q);
 460                         q ^= '"' ^ '\'';
 461                         putchar(q);
 462                 }
 463                 putchar(*c);
 464         }
 465         putchar(q);
 466 }
 467
 468 void print_escape(char *str)
 469 {
 470         /* print str, but change space and tab to '_'
 471          * as is suitable for device names
 472          */
 473         for (; *str; str++) {
 474                 switch (*str) {
 475                 case ' ':
 476                 case '\t':
 477                         putchar('_');
 478                         break;
 479                 case '/':
 480                         putchar('-');
 481                         break;
 482                 default:
 483                         putchar(*str);
 484                 }
 485         }
 486 }
 487
 488 int check_env(char *name)
 489 {
 490         char *val = getenv(name);
 491
 492         if (val && atoi(val) == 1)
 493                 return 1;
 494
 495         return 0;
 496 }
 497
 498 int use_udev(void)
 499 {
 500         static int use = -1;
 501         struct stat stb;
 502
 503         if (use < 0) {
 504                 use = ((stat("/dev/.udev", &stb) == 0 ||
 505                         stat("/run/udev", &stb) == 0) &&
 506                        check_env("MDADM_NO_UDEV") == 0);
 507         }
 508         return use;
 509 }
 510
 511 unsigned long GCD(unsigned long a, unsigned long b)
 512 {
 513         while (a != b) {
 514                 if (a < b)
 515                         b -= a;
 516                 if (b < a)
 517                         a -= b;
 518         }
 519         return a;
 520 }
 521
 522 /*
 523  * conf_line reads one logical line from the conffile or mdstat.
 524  * It skips comments and continues until it finds a line that starts
 525  * with a non blank/comment.  This character is pushed back for the next call
 526  * A doubly linked list of words is returned.
 527  * the first word will be a keyword.  Other words will have had quotes removed.
 528  */
 529
 530 char *conf_line(FILE *file)
 531 {
 532         char *w;
 533         char *list;
 534
 535         w = conf_word(file, 1);
 536         if (w == NULL)
 537                 return NULL;
 538
 539         list = dl_strdup(w);
 540         free(w);
 541         dl_init(list);
 542
 543         while ((w = conf_word(file, 0))){
 544                 char *w2 = dl_strdup(w);
 545                 free(w);
 546                 dl_add(list, w2);
 547         }
 548 /*    printf("got a line\n");*/
 549         return list;
 550 }
 551
 552 void free_line(char *line)
 553 {
 554         char *w;
 555         for (w = dl_next(line); w != line; w = dl_next(line)) {
 556                 dl_del(w);
 557                 dl_free(w);
 558         }
 559         dl_free(line);
 560 }
 561
 562 /**
 563  * parse_num() - Parse int from string.
 564  * @dest: Pointer to destination.
 565  * @num: Pointer to string that is going to be parsed.
 566  *
 567  * If string contains anything after a number, error code is returned.
 568  * The same happens when number is bigger than INT_MAX or smaller than 0.
 569  * Writes to destination only if successfully read the number.
 570  *
 571  * Return: 0 on success, 1 otherwise.
 572  */
 573 int parse_num(int *dest, char *num)
 574 {
 575         char *c = NULL;
 576         long temp;
 577
 578         if (!num)
 579                 return 1;
 580
 581         errno = 0;
 582         temp = strtol(num, &c, 10);
 583         if (temp < 0 || temp > INT_MAX || *c || errno != 0 || num == c)
 584                 return 1;
 585         *dest = temp;
 586         return 0;
 587 }