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