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  * convert a major/minor pair for a block device into a name in /dev, if possible.
 117  * On the first call, walk /dev collecting name.
 118  * Put them in a simple linked listfor now.
 119  */
 120 struct devmap {
 121         int major, minor;
 122         char *name;
 123         struct devmap *next;
 124 } *devlist = NULL;
 125 int devlist_ready = 0;
 126
 127 int add_dev(const char *name, const struct stat *stb, int flag, struct FTW *s)
 128 {
 129         struct stat st;
 130
 131         if (S_ISLNK(stb->st_mode)) {
 132                 if (stat(name, &st) != 0)
 133                         return 0;
 134                 stb = &st;
 135         }
 136
 137         if ((stb->st_mode&S_IFMT)== S_IFBLK) {
 138                 char *n = xstrdup(name);
 139                 struct devmap *dm = xmalloc(sizeof(*dm));
 140                 if (strncmp(n, "/dev/./", 7)==0)
 141                         strcpy(n+4, name+6);
 142                 if (dm) {
 143                         dm->major = major(stb->st_rdev);
 144                         dm->minor = minor(stb->st_rdev);
 145                         dm->name = n;
 146                         dm->next = devlist;
 147                         devlist = dm;
 148                 }
 149         }
 150         return 0;
 151 }
 152
 153 #ifndef HAVE_NFTW
 154 #ifdef HAVE_FTW
 155 int add_dev_1(const char *name, const struct stat *stb, int flag)
 156 {
 157         return add_dev(name, stb, flag, NULL);
 158 }
 159 int nftw(const char *path, int (*han)(const char *name, const struct stat *stb, int flag, struct FTW *s), int nopenfd, int flags)
 160 {
 161         return ftw(path, add_dev_1, nopenfd);
 162 }
 163 #else
 164 int nftw(const char *path, int (*han)(const char *name, const struct stat *stb, int flag, struct FTW *s), int nopenfd, int flags)
 165 {
 166         return 0;
 167 }
 168 #endif /* HAVE_FTW */
 169 #endif /* HAVE_NFTW */
 170
 171 /*
 172  * Find a block device with the right major/minor number.
 173  * If we find multiple names, choose the shortest.
 174  * If we find a name in /dev/md/, we prefer that.
 175  * This applies only to names for MD devices.
 176  * If 'prefer' is set (normally to e.g. /by-path/)
 177  * then we prefer a name which contains that string.
 178  */
 179 char *map_dev_preferred(int major, int minor, int create,
 180                         char *prefer)
 181 {
 182         struct devmap *p;
 183         char *regular = NULL, *preferred=NULL;
 184         int did_check = 0;
 185
 186         if (major == 0 && minor == 0)
 187                         return NULL;
 188
 189  retry:
 190         if (!devlist_ready) {
 191                 char *dev = "/dev";
 192                 struct stat stb;
 193                 while(devlist) {
 194                         struct devmap *d = devlist;
 195                         devlist = d->next;
 196                         free(d->name);
 197                         free(d);
 198                 }
 199                 if (lstat(dev, &stb)==0 &&
 200                     S_ISLNK(stb.st_mode))
 201                         dev = "/dev/.";
 202                 nftw(dev, add_dev, 10, FTW_PHYS);
 203                 devlist_ready=1;
 204                 did_check = 1;
 205         }
 206
 207         for (p=devlist; p; p=p->next)
 208                 if (p->major == major &&
 209                     p->minor == minor) {
 210                         if (strncmp(p->name, "/dev/md/",8) == 0
 211                             || (prefer && strstr(p->name, prefer))) {
 212                                 if (preferred == NULL ||
 213                                     strlen(p->name) < strlen(preferred))
 214                                         preferred = p->name;
 215                         } else {
 216                                 if (regular == NULL ||
 217                                     strlen(p->name) < strlen(regular))
 218                                         regular = p->name;
 219                         }
 220                 }
 221         if (!regular && !preferred && !did_check) {
 222                 devlist_ready = 0;
 223                 goto retry;
 224         }
 225         if (create && !regular && !preferred) {
 226                 static char buf[30];
 227                 snprintf(buf, sizeof(buf), "%d:%d", major, minor);
 228                 regular = buf;
 229         }
 230
 231         return preferred ? preferred : regular;
 232 }
 233
 234 /* conf_word gets one word from the conf file.
 235  * if "allow_key", then accept words at the start of a line,
 236  * otherwise stop when such a word is found.
 237  * We assume that the file pointer is at the end of a word, so the
 238  * next character is a space, or a newline.  If not, it is the start of a line.
 239  */
 240
 241 char *conf_word(FILE *file, int allow_key)
 242 {
 243         int wsize = 100;
 244         int len = 0;
 245         int c;
 246         int quote;
 247         int wordfound = 0;
 248         char *word = xmalloc(wsize);
 249
 250         while (wordfound==0) {
 251                 /* at the end of a word.. */
 252                 c = getc(file);
 253                 if (c == '#')
 254                         while (c != EOF && c != '\n')
 255                                 c = getc(file);
 256                 if (c == EOF) break;
 257                 if (c == '\n') continue;
 258
 259                 if (c != ' ' && c != '\t' && ! allow_key) {
 260                         ungetc(c, file);
 261                         break;
 262                 }
 263                 /* looks like it is safe to get a word here, if there is one */
 264                 quote = 0;
 265                 /* first, skip any spaces */
 266                 while (c == ' ' || c == '\t')
 267                         c = getc(file);
 268                 if (c != EOF && c != '\n' && c != '#') {
 269                         /* we really have a character of a word, so start saving it */
 270                         while (c != EOF && c != '\n' && (quote || (c!=' ' && c != '\t'))) {
 271                                 wordfound = 1;
 272                                 if (quote && c == quote) quote = 0;
 273                                 else if (quote == 0 && (c == '\'' || c == '"'))
 274                                         quote = c;
 275                                 else {
 276                                         if (len == wsize-1) {
 277                                                 wsize += 100;
 278                                                 word = xrealloc(word, wsize);
 279                                         }
 280                                         word[len++] = c;
 281                                 }
 282                                 c = getc(file);
 283                                 /* Hack for broken kernels (2.6.14-.24) that put
 284                                  *        "active(auto-read-only)"
 285                                  * in /proc/mdstat instead of
 286                                  *        "active (auto-read-only)"
 287                                  */
 288                                 if (c == '(' && len >= 6
 289                                     && strncmp(word+len-6, "active", 6) == 0)
 290                                         c = ' ';
 291                         }
 292                 }
 293                 if (c != EOF) ungetc(c, file);
 294         }
 295         word[len] = 0;
 296
 297         /* Further HACK for broken kernels.. 2.6.14-2.6.24 */
 298         if (strcmp(word, "auto-read-only)") == 0)
 299                 strcpy(word, "(auto-read-only)");
 300
 301 /*    printf("word is <%s>\n", word); */
 302         if (!wordfound) {
 303                 free(word);
 304                 word = NULL;
 305         }
 306         return word;
 307 }
 308
 309 void print_quoted(char *str)
 310 {
 311         /* Printf the string with surrounding quotes
 312          * iff needed.
 313          * If no space, tab, or quote - leave unchanged.
 314          * Else print surrounded by " or ', swapping quotes
 315          * when we find one that will cause confusion.
 316          */
 317
 318         char first_quote = 0, q;
 319         char *c;
 320
 321         for (c = str; *c; c++) {
 322                 switch(*c) {
 323                 case '\'':
 324                 case '"':
 325                         first_quote = *c;
 326                         break;
 327                 case ' ':
 328                 case '\t':
 329                         first_quote = *c;
 330                         continue;
 331                 default:
 332                         continue;
 333                 }
 334                 break;
 335         }
 336         if (!first_quote) {
 337                 printf("%s", str);
 338                 return;
 339         }
 340
 341         if (first_quote == '"')
 342                 q = '\'';
 343         else
 344                 q = '"';
 345         putchar(q);
 346         for (c = str; *c; c++) {
 347                 if (*c == q) {
 348                         putchar(q);
 349                         q ^= '"' ^ '\'';
 350                         putchar(q);
 351                 }
 352                 putchar(*c);
 353         }
 354         putchar(q);
 355 }
 356
 357 void print_escape(char *str)
 358 {
 359         /* print str, but change space and tab to '_'
 360          * as is suitable for device names
 361          */
 362         for (; *str ; str++) {
 363                 switch (*str) {
 364                 case ' ':
 365                 case '\t':
 366                         putchar('_');
 367                         break;
 368                 case '/':
 369                         putchar('-');
 370                         break;
 371                 default:
 372                         putchar(*str);
 373                 }
 374         }
 375 }
 376
 377 int check_env(char *name)
 378 {
 379         char *val = getenv(name);
 380
 381         if (val && atoi(val) == 1)
 382                 return 1;
 383
 384         return 0;
 385 }
 386
 387 int use_udev(void)
 388 {
 389         static int use = -1;
 390         struct stat stb;
 391
 392         if (use < 0) {
 393                 use = ((stat("/dev/.udev", &stb) == 0
 394                         || stat("/run/udev", &stb) == 0)
 395                        && check_env("MDADM_NO_UDEV") == 0);
 396         }
 397         return use;
 398 }