libdm/libdm-string.c

   1 /*
   2  * Copyright (C) 2006-2012 Red Hat, Inc. All rights reserved.
   3  *
   4  * This file is part of the device-mapper userspace tools.
   5  *
   6  * This copyrighted material is made available to anyone wishing to use,
   7  * modify, copy, or redistribute it subject to the terms and conditions
   8  * of the GNU Lesser General Public License v.2.1.
   9  *
  10  * You should have received a copy of the GNU Lesser General Public License
  11  * along with this program; if not, write to the Free Software Foundation,
  12  * Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  13  */
  14
  15 #include "dmlib.h"
  16
  17 #include <ctype.h>
  18
  19 /*
  20  * consume characters while they match the predicate function.
  21  */
  22 static char *_consume(char *buffer, int (*fn) (int))
  23 {
  24         while (*buffer && fn(*buffer))
  25                 buffer++;
  26
  27         return buffer;
  28 }
  29
  30 static int _isword(int c)
  31 {
  32         return !isspace(c);
  33 }
  34
  35 /*
  36  * Split buffer into NULL-separated words in argv.
  37  * Returns number of words.
  38  */
  39 int dm_split_words(char *buffer, unsigned max,
  40                    unsigned ignore_comments __attribute__((unused)),
  41                    char **argv)
  42 {
  43         unsigned arg;
  44
  45         for (arg = 0; arg < max; arg++) {
  46                 buffer = _consume(buffer, isspace);
  47                 if (!*buffer)
  48                         break;
  49
  50                 argv[arg] = buffer;
  51                 buffer = _consume(buffer, _isword);
  52
  53                 if (*buffer) {
  54                         *buffer = '\0';
  55                         buffer++;
  56                 }
  57         }
  58
  59         return arg;
  60 }
  61
  62 /*
  63  * Remove hyphen quoting from a component of a name.
  64  * NULL-terminates the component and returns start of next component.
  65  */
  66 static char *_unquote(char *component)
  67 {
  68         char *c = component;
  69         char *o = c;
  70         char *r;
  71
  72         while (*c) {
  73                 if (*(c + 1)) {
  74                         if (*c == '-') {
  75                                 if (*(c + 1) == '-')
  76                                         c++;
  77                                 else
  78                                         break;
  79                         }
  80                 }
  81                 *o = *c;
  82                 o++;
  83                 c++;
  84         }
  85
  86         r = (*c) ? c + 1 : c;
  87         *o = '\0';
  88
  89         return r;
  90 }
  91
  92 int dm_split_lvm_name(struct dm_pool *mem, const char *dmname,
  93                       char **vgname, char **lvname, char **layer)
  94 {
  95         if (mem && !(*vgname = dm_pool_strdup(mem, dmname)))
  96                 return 0;
  97
  98         _unquote(*layer = _unquote(*lvname = _unquote(*vgname)));
  99
 100         return 1;
 101 }
 102
 103 /*
 104  * On error, up to glibc 2.0.6, snprintf returned -1 if buffer was too small;
 105  * From glibc 2.1 it returns number of chars (excl. trailing null) that would
 106  * have been written had there been room.
 107  *
 108  * dm_snprintf reverts to the old behaviour.
 109  */
 110 int dm_snprintf(char *buf, size_t bufsize, const char *format, ...)
 111 {
 112         int n;
 113         va_list ap;
 114
 115         va_start(ap, format);
 116         n = vsnprintf(buf, bufsize, format, ap);
 117         va_end(ap);
 118
 119         if (n < 0 || ((unsigned) n + 1 > bufsize))
 120                 return -1;
 121
 122         return n;
 123 }
 124
 125 const char *dm_basename(const char *path)
 126 {
 127         const char *p = strrchr(path, '/');
 128
 129         return p ? p + 1 : path;
 130 }
 131
 132 int dm_asprintf(char **result, const char *format, ...)
 133 {
 134         int i, n, size = 16;
 135         va_list ap;
 136         char *buf = dm_malloc(size);
 137
 138         *result = 0;
 139
 140         if (!buf)
 141                 return -1;
 142
 143         for (i = 0;; i++) {
 144                 va_start(ap, format);
 145                 n = vsnprintf(buf, size, format, ap);
 146                 va_end(ap);
 147
 148                 if (0 <= n && n < size)
 149                         break;
 150
 151                 dm_free(buf);
 152                 /* Up to glibc 2.0.6 returns -1 */
 153                 size = (n < 0) ? size * 2 : n + 1;
 154                 if (!(buf = dm_malloc(size)))
 155                         return -1;
 156         }
 157
 158         if (i > 1) {
 159                 /* Reallocating more then once? */
 160                 if (!(*result = dm_strdup(buf))) {
 161                         dm_free(buf);
 162                         return -1;
 163                 }
 164                 dm_free(buf);
 165         } else
 166                 *result = buf;
 167
 168         return n + 1;
 169 }
 170
 171 /*
 172  * Count occurences of 'c' in 'str' until we reach a null char.
 173  *
 174  * Returns:
 175  *  len - incremented for each char we encounter.
 176  *  count - number of occurrences of 'c' and 'c2'.
 177  */
 178 static void _count_chars(const char *str, size_t *len, int *count,
 179                          const int c1, const int c2)
 180 {
 181         const char *ptr;
 182
 183         for (ptr = str; *ptr; ptr++, (*len)++)
 184                 if (*ptr == c1 || *ptr == c2)
 185                         (*count)++;
 186 }
 187
 188 /*
 189  * Count occurrences of 'c' in 'str' of length 'size'.
 190  *
 191  * Returns:
 192  *   Number of occurrences of 'c'
 193  */
 194 unsigned dm_count_chars(const char *str, size_t len, const int c)
 195 {
 196         size_t i;
 197         unsigned count = 0;
 198
 199         for (i = 0; i < len; i++)
 200                 if (str[i] == c)
 201                         count++;
 202
 203         return count;
 204 }
 205
 206 /*
 207  * Length of string after escaping double quotes and backslashes.
 208  */
 209 size_t dm_escaped_len(const char *str)
 210 {
 211         size_t len = 1;
 212         int count = 0;
 213
 214         _count_chars(str, &len, &count, '\"', '\\');
 215
 216         return count + len;
 217 }
 218
 219 /*
 220  * Copies a string, quoting orig_char with quote_char.
 221  * Optionally also quote quote_char.
 222  */
 223 static void _quote_characters(char **out, const char *src,
 224                               const int orig_char, const int quote_char,
 225                               int quote_quote_char)
 226 {
 227         while (*src) {
 228                 if (*src == orig_char ||
 229                     (*src == quote_char && quote_quote_char))
 230                         *(*out)++ = quote_char;
 231
 232                 *(*out)++ = *src++;
 233         }
 234 }
 235
 236 static void _unquote_one_character(char *src, const char orig_char,
 237                                    const char quote_char)
 238 {
 239         char *out;
 240         char s, n;
 241
 242         /* Optimise for the common case where no changes are needed. */
 243         while ((s = *src++)) {
 244                 if (s == quote_char &&
 245                     ((n = *src) == orig_char || n == quote_char)) {
 246                         out = src++;
 247                         *(out - 1) = n;
 248
 249                         while ((s = *src++)) {
 250                                 if (s == quote_char &&
 251                                     ((n = *src) == orig_char || n == quote_char)) {
 252                                         s = n;
 253                                         src++;
 254                                 }
 255                                 *out = s;
 256                                 out++;
 257                         }
 258
 259                         *out = '\0';
 260                         return;
 261                 }
 262         }
 263 }
 264
 265 /*
 266  * Unquote each character given in orig_char array and unquote quote_char
 267  * as well. Also save the first occurrence of each character from orig_char
 268  * that was found unquoted in arr_substr_first_unquoted array. This way we can
 269  * process several characters in one go.
 270  */
 271 static void _unquote_characters(char *src, const char *orig_chars,
 272                                 size_t num_orig_chars,
 273                                 const char quote_char,
 274                                 char *arr_substr_first_unquoted[])
 275 {
 276         char *out = src;
 277         char c, s, n;
 278         unsigned i;
 279
 280         while ((s = *src++)) {
 281                 for (i = 0; i < num_orig_chars; i++) {
 282                         c = orig_chars[i];
 283                         if (s == quote_char &&
 284                             ((n = *src) == c || n == quote_char)) {
 285                                 s = n;
 286                                 src++;
 287                                 break;
 288                         }
 289                         if (arr_substr_first_unquoted && (s == c) &&
 290                             !arr_substr_first_unquoted[i])
 291                                 arr_substr_first_unquoted[i] = out;
 292                 };
 293                 *out++ = s;
 294         }
 295
 296         *out = '\0';
 297 }
 298
 299 /*
 300  * Copies a string, quoting hyphens with hyphens.
 301  */
 302 static void _quote_hyphens(char **out, const char *src)
 303 {
 304         _quote_characters(out, src, '-', '-', 0);
 305 }
 306
 307 /*
 308  * <vg>-<lv>-<layer> or if !layer just <vg>-<lv>.
 309  */
 310 char *dm_build_dm_name(struct dm_pool *mem, const char *vgname,
 311                        const char *lvname, const char *layer)
 312 {
 313         size_t len = 1;
 314         int hyphens = 1;
 315         char *r, *out;
 316
 317         _count_chars(vgname, &len, &hyphens, '-', 0);
 318         _count_chars(lvname, &len, &hyphens, '-', 0);
 319
 320         if (layer && *layer) {
 321                 _count_chars(layer, &len, &hyphens, '-', 0);
 322                 hyphens++;
 323         }
 324
 325         len += hyphens;
 326
 327         if (!(r = dm_pool_alloc(mem, len))) {
 328                 log_error("build_dm_name: Allocation failed for %" PRIsize_t
 329                           " for %s %s %s.", len, vgname, lvname, layer);
 330                 return NULL;
 331         }
 332
 333         out = r;
 334         _quote_hyphens(&out, vgname);
 335         *out++ = '-';
 336         _quote_hyphens(&out, lvname);
 337
 338         if (layer && *layer) {
 339                 /* No hyphen if the layer begins with _ e.g. _mlog */
 340                 if (*layer != '_')
 341                         *out++ = '-';
 342                 _quote_hyphens(&out, layer);
 343         }
 344         *out = '\0';
 345
 346         return r;
 347 }
 348
 349 char *dm_build_dm_uuid(struct dm_pool *mem, const char *uuid_prefix, const char *lvid, const char *layer)
 350 {
 351         char *dmuuid;
 352         size_t len;
 353
 354         if (!layer)
 355                 layer = "";
 356
 357         len = strlen(uuid_prefix) + strlen(lvid) + strlen(layer) + 2;
 358
 359         if (!(dmuuid = dm_pool_alloc(mem, len))) {
 360                 log_error("build_dm_name: Allocation failed for %" PRIsize_t
 361                           " %s %s.", len, lvid, layer);
 362                 return NULL;
 363         }
 364
 365         sprintf(dmuuid, "%s%s%s%s", uuid_prefix, lvid, (*layer) ? "-" : "", layer);
 366
 367         return dmuuid;
 368 }
 369
 370 /*
 371  * Copies a string, quoting double quotes with backslashes.
 372  */
 373 char *dm_escape_double_quotes(char *out, const char *src)
 374 {
 375         char *buf = out;
 376
 377         _quote_characters(&buf, src, '\"', '\\', 1);
 378         *buf = '\0';
 379
 380         return out;
 381 }
 382
 383 /*
 384  * Undo quoting in situ.
 385  */
 386 void dm_unescape_double_quotes(char *src)
 387 {
 388         _unquote_one_character(src, '\"', '\\');
 389 }
 390
 391 /*
 392  * Unescape colons and "at" signs in situ and save the substrings
 393  * starting at the position of the first unescaped colon and the
 394  * first unescaped "at" sign. This is normally used to unescape
 395  * device names used as PVs.
 396  */
 397 void dm_unescape_colons_and_at_signs(char *src,
 398                                      char **substr_first_unquoted_colon,
 399                                      char **substr_first_unquoted_at_sign)
 400 {
 401         const char *orig_chars = ":@";
 402         char *arr_substr_first_unquoted[] = {NULL, NULL, NULL};
 403
 404         _unquote_characters(src, orig_chars, 2, '\\', arr_substr_first_unquoted);
 405
 406         if (substr_first_unquoted_colon)
 407                 *substr_first_unquoted_colon = arr_substr_first_unquoted[0];
 408
 409         if (substr_first_unquoted_at_sign)
 410                 *substr_first_unquoted_at_sign = arr_substr_first_unquoted[1];
 411 }
 412
 413 int dm_strncpy(char *dest, const char *src, size_t n)
 414 {
 415         if (memccpy(dest, src, 0, n))
 416                 return 1;
 417
 418         if (n > 0)
 419                 dest[n - 1] = '\0';
 420
 421         return 0;
 422 }