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
  61 void fmt_devname(char *name, int num)
  62 {
  63         if (num >= 0)
  64                 sprintf(name, "md%d", num);
  65         else
  66                 sprintf(name, "md_d%d", -1-num);
  67 }
  68
  69 char *devnum2devname(int num)
  70 {
  71         char name[100];
  72         fmt_devname(name,num);
  73         return strdup(name);
  74 }
  75
  76 int devname2devnum(char *name)
  77 {
  78         char *ep;
  79         int num;
  80         if (strncmp(name, "md_d", 4)==0)
  81                 num = -1-strtoul(name+4, &ep, 10);
  82         else
  83                 num = strtoul(name+2, &ep, 10);
  84         return num;
  85 }
  86
  87 int stat2devnum(struct stat *st)
  88 {
  89         char path[30];
  90         char link[200];
  91         char *cp;
  92         int n;
  93
  94         if ((S_IFMT & st->st_mode) == S_IFBLK) {
  95                 if (major(st->st_rdev) == MD_MAJOR)
  96                         return minor(st->st_rdev);
  97                 else if (major(st->st_rdev) == (unsigned)get_mdp_major())
  98                         return -1- (minor(st->st_rdev)>>MdpMinorShift);
  99
 100                 /* must be an extended-minor partition. Look at the
 101                  * /sys/dev/block/%d:%d link which must look like
 102                  * ../../block/mdXXX/mdXXXpYY
 103                  */
 104                 sprintf(path, "/sys/dev/block/%d:%d", major(st->st_rdev),
 105                         minor(st->st_rdev));
 106                 n = readlink(path, link, sizeof(link)-1);
 107                 if (n <= 0)
 108                         return NoMdDev;
 109                 link[n] = 0;
 110                 cp = strrchr(link, '/');
 111                 if (cp) *cp = 0;
 112                 cp = strrchr(link, '/');
 113                 if (cp && strncmp(cp, "/md", 3) == 0)
 114                         return devname2devnum(cp+1);
 115         }
 116         return NoMdDev;
 117
 118 }
 119
 120 int fd2devnum(int fd)
 121 {
 122         struct stat stb;
 123         if (fstat(fd, &stb) == 0)
 124                 return stat2devnum(&stb);
 125         return NoMdDev;
 126 }
 127
 128
 129
 130 /*
 131  * convert a major/minor pair for a block device into a name in /dev, if possible.
 132  * On the first call, walk /dev collecting name.
 133  * Put them in a simple linked listfor now.
 134  */
 135 struct devmap {
 136     int major, minor;
 137     char *name;
 138     struct devmap *next;
 139 } *devlist = NULL;
 140 int devlist_ready = 0;
 141
 142 int add_dev(const char *name, const struct stat *stb, int flag, struct FTW *s)
 143 {
 144         struct stat st;
 145
 146         if (S_ISLNK(stb->st_mode)) {
 147                 if (stat(name, &st) != 0)
 148                         return 0;
 149                 stb = &st;
 150         }
 151
 152         if ((stb->st_mode&S_IFMT)== S_IFBLK) {
 153                 char *n = strdup(name);
 154                 struct devmap *dm = malloc(sizeof(*dm));
 155                 if (strncmp(n, "/dev/./", 7)==0)
 156                         strcpy(n+4, name+6);
 157                 if (dm) {
 158                         dm->major = major(stb->st_rdev);
 159                         dm->minor = minor(stb->st_rdev);
 160                         dm->name = n;
 161                         dm->next = devlist;
 162                         devlist = dm;
 163                 }
 164         }
 165         return 0;
 166 }
 167
 168 #ifndef HAVE_NFTW
 169 #ifdef HAVE_FTW
 170 int add_dev_1(const char *name, const struct stat *stb, int flag)
 171 {
 172         return add_dev(name, stb, flag, NULL);
 173 }
 174 int nftw(const char *path, int (*han)(const char *name, const struct stat *stb, int flag, struct FTW *s), int nopenfd, int flags)
 175 {
 176         return ftw(path, add_dev_1, nopenfd);
 177 }
 178 #else
 179 int nftw(const char *path, int (*han)(const char *name, const struct stat *stb, int flag, struct FTW *s), int nopenfd, int flags)
 180 {
 181         return 0;
 182 }
 183 #endif /* HAVE_FTW */
 184 #endif /* HAVE_NFTW */
 185
 186 /*
 187  * Find a block device with the right major/minor number.
 188  * If we find multiple names, choose the shortest.
 189  * If we find a name in /dev/md/, we prefer that.
 190  * This applies only to names for MD devices.
 191  * If 'prefer' is set (normally to e.g. /by-path/)
 192  * then we prefer a name which contains that string.
 193  */
 194 char *map_dev_preferred(int major, int minor, int create,
 195                         char *prefer)
 196 {
 197         struct devmap *p;
 198         char *regular = NULL, *preferred=NULL;
 199         int did_check = 0;
 200
 201         if (major == 0 && minor == 0)
 202                         return NULL;
 203
 204  retry:
 205         if (!devlist_ready) {
 206                 char *dev = "/dev";
 207                 struct stat stb;
 208                 while(devlist) {
 209                         struct devmap *d = devlist;
 210                         devlist = d->next;
 211                         free(d->name);
 212                         free(d);
 213                 }
 214                 if (lstat(dev, &stb)==0 &&
 215                     S_ISLNK(stb.st_mode))
 216                         dev = "/dev/.";
 217                 nftw(dev, add_dev, 10, FTW_PHYS);
 218                 devlist_ready=1;
 219                 did_check = 1;
 220         }
 221
 222         for (p=devlist; p; p=p->next)
 223                 if (p->major == major &&
 224                     p->minor == minor) {
 225                         if (strncmp(p->name, "/dev/md/",8) == 0
 226                             || (prefer && strstr(p->name, prefer))) {
 227                                 if (preferred == NULL ||
 228                                     strlen(p->name) < strlen(preferred))
 229                                         preferred = p->name;
 230                         } else {
 231                                 if (regular == NULL ||
 232                                     strlen(p->name) < strlen(regular))
 233                                         regular = p->name;
 234                         }
 235                 }
 236         if (!regular && !preferred && !did_check) {
 237                 devlist_ready = 0;
 238                 goto retry;
 239         }
 240         if (create && !regular && !preferred) {
 241                 static char buf[30];
 242                 snprintf(buf, sizeof(buf), "%d:%d", major, minor);
 243                 regular = buf;
 244         }
 245
 246         return preferred ? preferred : regular;
 247 }
 248
 249
 250
 251 /* conf_word gets one word from the conf file.
 252  * if "allow_key", then accept words at the start of a line,
 253  * otherwise stop when such a word is found.
 254  * We assume that the file pointer is at the end of a word, so the
 255  * next character is a space, or a newline.  If not, it is the start of a line.
 256  */
 257
 258 char *conf_word(FILE *file, int allow_key)
 259 {
 260         int wsize = 100;
 261         int len = 0;
 262         int c;
 263         int quote;
 264         int wordfound = 0;
 265         char *word = malloc(wsize);
 266
 267         if (!word) abort();
 268
 269         while (wordfound==0) {
 270                 /* at the end of a word.. */
 271                 c = getc(file);
 272                 if (c == '#')
 273                         while (c != EOF && c != '\n')
 274                                 c = getc(file);
 275                 if (c == EOF) break;
 276                 if (c == '\n') continue;
 277
 278                 if (c != ' ' && c != '\t' && ! allow_key) {
 279                         ungetc(c, file);
 280                         break;
 281                 }
 282                 /* looks like it is safe to get a word here, if there is one */
 283                 quote = 0;
 284                 /* first, skip any spaces */
 285                 while (c == ' ' || c == '\t')
 286                         c = getc(file);
 287                 if (c != EOF && c != '\n' && c != '#') {
 288                         /* we really have a character of a word, so start saving it */
 289                         while (c != EOF && c != '\n' && (quote || (c!=' ' && c != '\t'))) {
 290                                 wordfound = 1;
 291                                 if (quote && c == quote) quote = 0;
 292                                 else if (quote == 0 && (c == '\'' || c == '"'))
 293                                         quote = c;
 294                                 else {
 295                                         if (len == wsize-1) {
 296                                                 wsize += 100;
 297                                                 word = realloc(word, wsize);
 298                                                 if (!word) abort();
 299                                         }
 300                                         word[len++] = c;
 301                                 }
 302                                 c = getc(file);
 303                                 /* Hack for broken kernels (2.6.14-.24) that put
 304                                  *        "active(auto-read-only)"
 305                                  * in /proc/mdstat instead of
 306                                  *        "active (auto-read-only)"
 307                                  */
 308                                 if (c == '(' && len >= 6
 309                                     && strncmp(word+len-6, "active", 6) == 0)
 310                                         c = ' ';
 311                         }
 312                 }
 313                 if (c != EOF) ungetc(c, file);
 314         }
 315         word[len] = 0;
 316
 317         /* Further HACK for broken kernels.. 2.6.14-2.6.24 */
 318         if (strcmp(word, "auto-read-only)") == 0)
 319                 strcpy(word, "(auto-read-only)");
 320
 321 /*    printf("word is <%s>\n", word); */
 322         if (!wordfound) {
 323                 free(word);
 324                 word = NULL;
 325         }
 326         return word;
 327 }
 328
 329 void print_quoted(char *str)
 330 {
 331         /* Printf the string with surrounding quotes
 332          * iff needed.
 333          * If no space, tab, or quote - leave unchanged.
 334          * Else print surrounded by " or ', swapping quotes
 335          * when we find one that will cause confusion.
 336          */
 337
 338         char first_quote = 0, q;
 339         char *c;
 340
 341         for (c = str; *c; c++) {
 342                 switch(*c) {
 343                 case '\'':
 344                 case '"':
 345                         first_quote = *c;
 346                         break;
 347                 case ' ':
 348                 case '\t':
 349                         first_quote = *c;
 350                         continue;
 351                 default:
 352                         continue;
 353                 }
 354                 break;
 355         }
 356         if (!first_quote) {
 357                 printf("%s", str);
 358                 return;
 359         }
 360
 361         if (first_quote == '"')
 362                 q = '\'';
 363         else
 364                 q = '"';
 365         putchar(q);
 366         for (c = str; *c; c++) {
 367                 if (*c == q) {
 368                         putchar(q);
 369                         q ^= '"' ^ '\'';
 370                         putchar(q);
 371                 }
 372                 putchar(*c);
 373         }
 374         putchar(q);
 375 }
 376
 377 void print_escape(char *str)
 378 {
 379         /* print str, but change space and tab to '_'
 380          * as is suitable for device names
 381          */
 382         for (; *str ; str++) {
 383                 switch (*str) {
 384                 case ' ':
 385                 case '\t':
 386                         putchar('_');
 387                         break;
 388                 case '/':
 389                         putchar('-');
 390                         break;
 391                 default:
 392                         putchar(*str);
 393                 }
 394         }
 395 }