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        <ctype.h>
  27
  28 /* This fill contains various 'library' style function.  They
  29  * have no dependency on anything outside this file.
  30  */
  31
  32 int get_mdp_major(void)
  33 {
  34 static int mdp_major = -1;
  35         FILE *fl;
  36         char *w;
  37         int have_block = 0;
  38         int have_devices = 0;
  39         int last_num = -1;
  40
  41         if (mdp_major != -1)
  42                 return mdp_major;
  43         fl = fopen("/proc/devices", "r");
  44         if (!fl)
  45                 return -1;
  46         while ((w = conf_word(fl, 1))) {
  47                 if (have_block && strcmp(w, "devices:")==0)
  48                         have_devices = 1;
  49                 have_block =  (strcmp(w, "Block")==0);
  50                 if (isdigit(w[0]))
  51                         last_num = atoi(w);
  52                 if (have_devices && strcmp(w, "mdp")==0)
  53                         mdp_major = last_num;
  54                 free(w);
  55         }
  56         fclose(fl);
  57         return mdp_major;
  58 }
  59
  60 char *devid2devnm(int devid)
  61 {
  62         char path[30];
  63         char link[200];
  64         static char devnm[32];
  65         char *cp, *ep;
  66         int n;
  67
  68         /* Might be an extended-minor partition or a
  69          * named md device. Look at the
  70          * /sys/dev/block/%d:%d link which must look like
  71          *    ../../block/mdXXX/mdXXXpYY
  72          * or
  73          *    ...../block/md_FOO
  74          */
  75         sprintf(path, "/sys/dev/block/%d:%d", major(devid),
  76                 minor(devid));
  77         n = readlink(path, link, sizeof(link)-1);
  78         if (n > 0) {
  79                 link[n] = 0;
  80                 cp = strstr(link, "/block/");
  81                 if (cp) {
  82                         cp += 7;
  83                         ep = strchr(cp, '/');
  84                         if (ep)
  85                                 *ep = 0;
  86                         strcpy(devnm, cp);
  87                         return devnm;
  88                 }
  89         }
  90         if (major(devid) == MD_MAJOR)
  91                 sprintf(devnm,"md%d", minor(devid));
  92         else if (major(devid) == (unsigned)get_mdp_major())
  93                 sprintf(devnm,"md_d%d",
  94                         (minor(devid)>>MdpMinorShift));
  95         else
  96                 return NULL;
  97         return devnm;
  98 }
  99
 100 char *stat2devnm(struct stat *st)
 101 {
 102         if ((S_IFMT & st->st_mode) != S_IFBLK)
 103                 return NULL;
 104         return devid2devnm(st->st_rdev);
 105 }
 106
 107 char *fd2devnm(int fd)
 108 {
 109         struct stat stb;
 110         if (fstat(fd, &stb) == 0)
 111                 return stat2devnm(&stb);
 112         return NULL;
 113 }
 114
 115
 116
 117 /*
 118  * convert a major/minor pair for a block device into a name in /dev, if possible.
 119  * On the first call, walk /dev collecting name.
 120  * Put them in a simple linked listfor now.
 121  */
 122 struct devmap {
 123         int major, minor;
 124         char *name;
 125         struct devmap *next;
 126 } *devlist = NULL;
 127 int devlist_ready = 0;
 128
 129 int add_dev(const char *name, const struct stat *stb, int flag, struct FTW *s)
 130 {
 131         struct stat st;
 132
 133         if (S_ISLNK(stb->st_mode)) {
 134                 if (stat(name, &st) != 0)
 135                         return 0;
 136                 stb = &st;
 137         }
 138
 139         if ((stb->st_mode&S_IFMT)== S_IFBLK) {
 140                 char *n = xstrdup(name);
 141                 struct devmap *dm = xmalloc(sizeof(*dm));
 142                 if (strncmp(n, "/dev/./", 7)==0)
 143                         strcpy(n+4, name+6);
 144                 if (dm) {
 145                         dm->major = major(stb->st_rdev);
 146                         dm->minor = minor(stb->st_rdev);
 147                         dm->name = n;
 148                         dm->next = devlist;
 149                         devlist = dm;
 150                 }
 151         }
 152         return 0;
 153 }
 154
 155 #ifndef HAVE_NFTW
 156 #ifdef HAVE_FTW
 157 int add_dev_1(const char *name, const struct stat *stb, int flag)
 158 {
 159         return add_dev(name, stb, flag, NULL);
 160 }
 161 int nftw(const char *path, int (*han)(const char *name, const struct stat *stb, int flag, struct FTW *s), int nopenfd, int flags)
 162 {
 163         return ftw(path, add_dev_1, nopenfd);
 164 }
 165 #else
 166 int nftw(const char *path, int (*han)(const char *name, const struct stat *stb, int flag, struct FTW *s), int nopenfd, int flags)
 167 {
 168         return 0;
 169 }
 170 #endif /* HAVE_FTW */
 171 #endif /* HAVE_NFTW */
 172
 173 /*
 174  * Find a block device with the right major/minor number.
 175  * If we find multiple names, choose the shortest.
 176  * If we find a name in /dev/md/, we prefer that.
 177  * This applies only to names for MD devices.
 178  * If 'prefer' is set (normally to e.g. /by-path/)
 179  * then we prefer a name which contains that string.
 180  */
 181 char *map_dev_preferred(int major, int minor, int create,
 182                         char *prefer)
 183 {
 184         struct devmap *p;
 185         char *regular = NULL, *preferred=NULL;
 186         int did_check = 0;
 187
 188         if (major == 0 && minor == 0)
 189                         return NULL;
 190
 191  retry:
 192         if (!devlist_ready) {
 193                 char *dev = "/dev";
 194                 struct stat stb;
 195                 while(devlist) {
 196                         struct devmap *d = devlist;
 197                         devlist = d->next;
 198                         free(d->name);
 199                         free(d);
 200                 }
 201                 if (lstat(dev, &stb)==0 &&
 202                     S_ISLNK(stb.st_mode))
 203                         dev = "/dev/.";
 204                 nftw(dev, add_dev, 10, FTW_PHYS);
 205                 devlist_ready=1;
 206                 did_check = 1;
 207         }
 208
 209         for (p=devlist; p; p=p->next)
 210                 if (p->major == major &&
 211                     p->minor == minor) {
 212                         if (strncmp(p->name, "/dev/md/",8) == 0
 213                             || (prefer && strstr(p->name, prefer))) {
 214                                 if (preferred == NULL ||
 215                                     strlen(p->name) < strlen(preferred))
 216                                         preferred = p->name;
 217                         } else {
 218                                 if (regular == NULL ||
 219                                     strlen(p->name) < strlen(regular))
 220                                         regular = p->name;
 221                         }
 222                 }
 223         if (!regular && !preferred && !did_check) {
 224                 devlist_ready = 0;
 225                 goto retry;
 226         }
 227         if (create && !regular && !preferred) {
 228                 static char buf[30];
 229                 snprintf(buf, sizeof(buf), "%d:%d", major, minor);
 230                 regular = buf;
 231         }
 232
 233         return preferred ? preferred : regular;
 234 }
 235
 236
 237
 238 /* conf_word gets one word from the conf file.
 239  * if "allow_key", then accept words at the start of a line,
 240  * otherwise stop when such a word is found.
 241  * We assume that the file pointer is at the end of a word, so the
 242  * next character is a space, or a newline.  If not, it is the start of a line.
 243  */
 244
 245 char *conf_word(FILE *file, int allow_key)
 246 {
 247         int wsize = 100;
 248         int len = 0;
 249         int c;
 250         int quote;
 251         int wordfound = 0;
 252         char *word = xmalloc(wsize);
 253
 254         while (wordfound==0) {
 255                 /* at the end of a word.. */
 256                 c = getc(file);
 257                 if (c == '#')
 258                         while (c != EOF && c != '\n')
 259                                 c = getc(file);
 260                 if (c == EOF) break;
 261                 if (c == '\n') continue;
 262
 263                 if (c != ' ' && c != '\t' && ! allow_key) {
 264                         ungetc(c, file);
 265                         break;
 266                 }
 267                 /* looks like it is safe to get a word here, if there is one */
 268                 quote = 0;
 269                 /* first, skip any spaces */
 270                 while (c == ' ' || c == '\t')
 271                         c = getc(file);
 272                 if (c != EOF && c != '\n' && c != '#') {
 273                         /* we really have a character of a word, so start saving it */
 274                         while (c != EOF && c != '\n' && (quote || (c!=' ' && c != '\t'))) {
 275                                 wordfound = 1;
 276                                 if (quote && c == quote) quote = 0;
 277                                 else if (quote == 0 && (c == '\'' || c == '"'))
 278                                         quote = c;
 279                                 else {
 280                                         if (len == wsize-1) {
 281                                                 wsize += 100;
 282                                                 word = xrealloc(word, wsize);
 283                                         }
 284                                         word[len++] = c;
 285                                 }
 286                                 c = getc(file);
 287                                 /* Hack for broken kernels (2.6.14-.24) that put
 288                                  *        "active(auto-read-only)"
 289                                  * in /proc/mdstat instead of
 290                                  *        "active (auto-read-only)"
 291                                  */
 292                                 if (c == '(' && len >= 6
 293                                     && strncmp(word+len-6, "active", 6) == 0)
 294                                         c = ' ';
 295                         }
 296                 }
 297                 if (c != EOF) ungetc(c, file);
 298         }
 299         word[len] = 0;
 300
 301         /* Further HACK for broken kernels.. 2.6.14-2.6.24 */
 302         if (strcmp(word, "auto-read-only)") == 0)
 303                 strcpy(word, "(auto-read-only)");
 304
 305 /*    printf("word is <%s>\n", word); */
 306         if (!wordfound) {
 307                 free(word);
 308                 word = NULL;
 309         }
 310         return word;
 311 }
 312
 313 void print_quoted(char *str)
 314 {
 315         /* Printf the string with surrounding quotes
 316          * iff needed.
 317          * If no space, tab, or quote - leave unchanged.
 318          * Else print surrounded by " or ', swapping quotes
 319          * when we find one that will cause confusion.
 320          */
 321
 322         char first_quote = 0, q;
 323         char *c;
 324
 325         for (c = str; *c; c++) {
 326                 switch(*c) {
 327                 case '\'':
 328                 case '"':
 329                         first_quote = *c;
 330                         break;
 331                 case ' ':
 332                 case '\t':
 333                         first_quote = *c;
 334                         continue;
 335                 default:
 336                         continue;
 337                 }
 338                 break;
 339         }
 340         if (!first_quote) {
 341                 printf("%s", str);
 342                 return;
 343         }
 344
 345         if (first_quote == '"')
 346                 q = '\'';
 347         else
 348                 q = '"';
 349         putchar(q);
 350         for (c = str; *c; c++) {
 351                 if (*c == q) {
 352                         putchar(q);
 353                         q ^= '"' ^ '\'';
 354                         putchar(q);
 355                 }
 356                 putchar(*c);
 357         }
 358         putchar(q);
 359 }
 360
 361 void print_escape(char *str)
 362 {
 363         /* print str, but change space and tab to '_'
 364          * as is suitable for device names
 365          */
 366         for (; *str ; str++) {
 367                 switch (*str) {
 368                 case ' ':
 369                 case '\t':
 370                         putchar('_');
 371                         break;
 372                 case '/':
 373                         putchar('-');
 374                         break;
 375                 default:
 376                         putchar(*str);
 377                 }
 378         }
 379 }
 380
 381 int use_udev(void)
 382 {
 383         static int use = -1;
 384         struct stat stb;
 385
 386         if (use < 0) {
 387                 use = ((stat("/dev/.udev", &stb) == 0
 388                         || stat("/run/udev", &stb) == 0)
 389                        && check_env("MDADM_NO_UDEV") == 0);
 390         }
 391         return use;
 392 }