src/basic/string-util.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2010 Lennart Poettering
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include <errno.h>
  21 #include <stdarg.h>
  22 #include <stdint.h>
  23 #include <stdio.h>
  24 #include <stdlib.h>
  25
  26 #include "alloc-util.h"
  27 #include "gunicode.h"
  28 #include "macro.h"
  29 #include "string-util.h"
  30 #include "utf8.h"
  31 #include "util.h"
  32
  33 int strcmp_ptr(const char *a, const char *b) {
  34
  35         /* Like strcmp(), but tries to make sense of NULL pointers */
  36         if (a && b)
  37                 return strcmp(a, b);
  38
  39         if (!a && b)
  40                 return -1;
  41
  42         if (a && !b)
  43                 return 1;
  44
  45         return 0;
  46 }
  47
  48 char* endswith(const char *s, const char *postfix) {
  49         size_t sl, pl;
  50
  51         assert(s);
  52         assert(postfix);
  53
  54         sl = strlen(s);
  55         pl = strlen(postfix);
  56
  57         if (pl == 0)
  58                 return (char*) s + sl;
  59
  60         if (sl < pl)
  61                 return NULL;
  62
  63         if (memcmp(s + sl - pl, postfix, pl) != 0)
  64                 return NULL;
  65
  66         return (char*) s + sl - pl;
  67 }
  68
  69 char* endswith_no_case(const char *s, const char *postfix) {
  70         size_t sl, pl;
  71
  72         assert(s);
  73         assert(postfix);
  74
  75         sl = strlen(s);
  76         pl = strlen(postfix);
  77
  78         if (pl == 0)
  79                 return (char*) s + sl;
  80
  81         if (sl < pl)
  82                 return NULL;
  83
  84         if (strcasecmp(s + sl - pl, postfix) != 0)
  85                 return NULL;
  86
  87         return (char*) s + sl - pl;
  88 }
  89
  90 char* first_word(const char *s, const char *word) {
  91         size_t sl, wl;
  92         const char *p;
  93
  94         assert(s);
  95         assert(word);
  96
  97         /* Checks if the string starts with the specified word, either
  98          * followed by NUL or by whitespace. Returns a pointer to the
  99          * NUL or the first character after the whitespace. */
 100
 101         sl = strlen(s);
 102         wl = strlen(word);
 103
 104         if (sl < wl)
 105                 return NULL;
 106
 107         if (wl == 0)
 108                 return (char*) s;
 109
 110         if (memcmp(s, word, wl) != 0)
 111                 return NULL;
 112
 113         p = s + wl;
 114         if (*p == 0)
 115                 return (char*) p;
 116
 117         if (!strchr(WHITESPACE, *p))
 118                 return NULL;
 119
 120         p += strspn(p, WHITESPACE);
 121         return (char*) p;
 122 }
 123
 124 static size_t strcspn_escaped(const char *s, const char *reject) {
 125         bool escaped = false;
 126         int n;
 127
 128         for (n=0; s[n]; n++) {
 129                 if (escaped)
 130                         escaped = false;
 131                 else if (s[n] == '\\')
 132                         escaped = true;
 133                 else if (strchr(reject, s[n]))
 134                         break;
 135         }
 136
 137         /* if s ends in \, return index of previous char */
 138         return n - escaped;
 139 }
 140
 141 /* Split a string into words. */
 142 const char* split(const char **state, size_t *l, const char *separator, bool quoted) {
 143         const char *current;
 144
 145         current = *state;
 146
 147         if (!*current) {
 148                 assert(**state == '\0');
 149                 return NULL;
 150         }
 151
 152         current += strspn(current, separator);
 153         if (!*current) {
 154                 *state = current;
 155                 return NULL;
 156         }
 157
 158         if (quoted && strchr("\'\"", *current)) {
 159                 char quotechars[2] = {*current, '\0'};
 160
 161                 *l = strcspn_escaped(current + 1, quotechars);
 162                 if (current[*l + 1] == '\0' || current[*l + 1] != quotechars[0] ||
 163                     (current[*l + 2] && !strchr(separator, current[*l + 2]))) {
 164                         /* right quote missing or garbage at the end */
 165                         *state = current;
 166                         return NULL;
 167                 }
 168                 *state = current++ + *l + 2;
 169         } else if (quoted) {
 170                 *l = strcspn_escaped(current, separator);
 171                 if (current[*l] && !strchr(separator, current[*l])) {
 172                         /* unfinished escape */
 173                         *state = current;
 174                         return NULL;
 175                 }
 176                 *state = current + *l;
 177         } else {
 178                 *l = strcspn(current, separator);
 179                 *state = current + *l;
 180         }
 181
 182         return current;
 183 }
 184
 185 char *strnappend(const char *s, const char *suffix, size_t b) {
 186         size_t a;
 187         char *r;
 188
 189         if (!s && !suffix)
 190                 return strdup("");
 191
 192         if (!s)
 193                 return strndup(suffix, b);
 194
 195         if (!suffix)
 196                 return strdup(s);
 197
 198         assert(s);
 199         assert(suffix);
 200
 201         a = strlen(s);
 202         if (b > ((size_t) -1) - a)
 203                 return NULL;
 204
 205         r = new(char, a+b+1);
 206         if (!r)
 207                 return NULL;
 208
 209         memcpy(r, s, a);
 210         memcpy(r+a, suffix, b);
 211         r[a+b] = 0;
 212
 213         return r;
 214 }
 215
 216 char *strappend(const char *s, const char *suffix) {
 217         return strnappend(s, suffix, suffix ? strlen(suffix) : 0);
 218 }
 219
 220 char *strjoin(const char *x, ...) {
 221         va_list ap;
 222         size_t l;
 223         char *r, *p;
 224
 225         va_start(ap, x);
 226
 227         if (x) {
 228                 l = strlen(x);
 229
 230                 for (;;) {
 231                         const char *t;
 232                         size_t n;
 233
 234                         t = va_arg(ap, const char *);
 235                         if (!t)
 236                                 break;
 237
 238                         n = strlen(t);
 239                         if (n > ((size_t) -1) - l) {
 240                                 va_end(ap);
 241                                 return NULL;
 242                         }
 243
 244                         l += n;
 245                 }
 246         } else
 247                 l = 0;
 248
 249         va_end(ap);
 250
 251         r = new(char, l+1);
 252         if (!r)
 253                 return NULL;
 254
 255         if (x) {
 256                 p = stpcpy(r, x);
 257
 258                 va_start(ap, x);
 259
 260                 for (;;) {
 261                         const char *t;
 262
 263                         t = va_arg(ap, const char *);
 264                         if (!t)
 265                                 break;
 266
 267                         p = stpcpy(p, t);
 268                 }
 269
 270                 va_end(ap);
 271         } else
 272                 r[0] = 0;
 273
 274         return r;
 275 }
 276
 277 char *strstrip(char *s) {
 278         char *e;
 279
 280         /* Drops trailing whitespace. Modifies the string in
 281          * place. Returns pointer to first non-space character */
 282
 283         s += strspn(s, WHITESPACE);
 284
 285         for (e = strchr(s, 0); e > s; e --)
 286                 if (!strchr(WHITESPACE, e[-1]))
 287                         break;
 288
 289         *e = 0;
 290
 291         return s;
 292 }
 293
 294 char *delete_chars(char *s, const char *bad) {
 295         char *f, *t;
 296
 297         /* Drops all whitespace, regardless where in the string */
 298
 299         for (f = s, t = s; *f; f++) {
 300                 if (strchr(bad, *f))
 301                         continue;
 302
 303                 *(t++) = *f;
 304         }
 305
 306         *t = 0;
 307
 308         return s;
 309 }
 310
 311 char *truncate_nl(char *s) {
 312         assert(s);
 313
 314         s[strcspn(s, NEWLINE)] = 0;
 315         return s;
 316 }
 317
 318 char ascii_tolower(char x) {
 319
 320         if (x >= 'A' && x <= 'Z')
 321                 return x - 'A' + 'a';
 322
 323         return x;
 324 }
 325
 326 char *ascii_strlower(char *t) {
 327         char *p;
 328
 329         assert(t);
 330
 331         for (p = t; *p; p++)
 332                 *p = ascii_tolower(*p);
 333
 334         return t;
 335 }
 336
 337 char *ascii_strlower_n(char *t, size_t n) {
 338         size_t i;
 339
 340         if (n <= 0)
 341                 return t;
 342
 343         for (i = 0; i < n; i++)
 344                 t[i] = ascii_tolower(t[i]);
 345
 346         return t;
 347 }
 348
 349 int ascii_strcasecmp_n(const char *a, const char *b, size_t n) {
 350
 351         for (; n > 0; a++, b++, n--) {
 352                 int x, y;
 353
 354                 x = (int) (uint8_t) ascii_tolower(*a);
 355                 y = (int) (uint8_t) ascii_tolower(*b);
 356
 357                 if (x != y)
 358                         return x - y;
 359         }
 360
 361         return 0;
 362 }
 363
 364 int ascii_strcasecmp_nn(const char *a, size_t n, const char *b, size_t m) {
 365         int r;
 366
 367         r = ascii_strcasecmp_n(a, b, MIN(n, m));
 368         if (r != 0)
 369                 return r;
 370
 371         if (n < m)
 372                 return -1;
 373         else if (n > m)
 374                 return 1;
 375         else
 376                 return 0;
 377 }
 378
 379 bool chars_intersect(const char *a, const char *b) {
 380         const char *p;
 381
 382         /* Returns true if any of the chars in a are in b. */
 383         for (p = a; *p; p++)
 384                 if (strchr(b, *p))
 385                         return true;
 386
 387         return false;
 388 }
 389
 390 bool string_has_cc(const char *p, const char *ok) {
 391         const char *t;
 392
 393         assert(p);
 394
 395         /*
 396          * Check if a string contains control characters. If 'ok' is
 397          * non-NULL it may be a string containing additional CCs to be
 398          * considered OK.
 399          */
 400
 401         for (t = p; *t; t++) {
 402                 if (ok && strchr(ok, *t))
 403                         continue;
 404
 405                 if (*t > 0 && *t < ' ')
 406                         return true;
 407
 408                 if (*t == 127)
 409                         return true;
 410         }
 411
 412         return false;
 413 }
 414
 415 static char *ascii_ellipsize_mem(const char *s, size_t old_length, size_t new_length, unsigned percent) {
 416         size_t x;
 417         char *r;
 418
 419         assert(s);
 420         assert(percent <= 100);
 421         assert(new_length >= 3);
 422
 423         if (old_length <= 3 || old_length <= new_length)
 424                 return strndup(s, old_length);
 425
 426         r = new0(char, new_length+1);
 427         if (!r)
 428                 return NULL;
 429
 430         x = (new_length * percent) / 100;
 431
 432         if (x > new_length - 3)
 433                 x = new_length - 3;
 434
 435         memcpy(r, s, x);
 436         r[x] = '.';
 437         r[x+1] = '.';
 438         r[x+2] = '.';
 439         memcpy(r + x + 3,
 440                s + old_length - (new_length - x - 3),
 441                new_length - x - 3);
 442
 443         return r;
 444 }
 445
 446 char *ellipsize_mem(const char *s, size_t old_length, size_t new_length, unsigned percent) {
 447         size_t x;
 448         char *e;
 449         const char *i, *j;
 450         unsigned k, len, len2;
 451         int r;
 452
 453         assert(s);
 454         assert(percent <= 100);
 455         assert(new_length >= 3);
 456
 457         /* if no multibyte characters use ascii_ellipsize_mem for speed */
 458         if (ascii_is_valid(s))
 459                 return ascii_ellipsize_mem(s, old_length, new_length, percent);
 460
 461         if (old_length <= 3 || old_length <= new_length)
 462                 return strndup(s, old_length);
 463
 464         x = (new_length * percent) / 100;
 465
 466         if (x > new_length - 3)
 467                 x = new_length - 3;
 468
 469         k = 0;
 470         for (i = s; k < x && i < s + old_length; i = utf8_next_char(i)) {
 471                 char32_t c;
 472
 473                 r = utf8_encoded_to_unichar(i, &c);
 474                 if (r < 0)
 475                         return NULL;
 476                 k += unichar_iswide(c) ? 2 : 1;
 477         }
 478
 479         if (k > x) /* last character was wide and went over quota */
 480                 x ++;
 481
 482         for (j = s + old_length; k < new_length && j > i; ) {
 483                 char32_t c;
 484
 485                 j = utf8_prev_char(j);
 486                 r = utf8_encoded_to_unichar(j, &c);
 487                 if (r < 0)
 488                         return NULL;
 489                 k += unichar_iswide(c) ? 2 : 1;
 490         }
 491         assert(i <= j);
 492
 493         /* we don't actually need to ellipsize */
 494         if (i == j)
 495                 return memdup(s, old_length + 1);
 496
 497         /* make space for ellipsis */
 498         j = utf8_next_char(j);
 499
 500         len = i - s;
 501         len2 = s + old_length - j;
 502         e = new(char, len + 3 + len2 + 1);
 503         if (!e)
 504                 return NULL;
 505
 506         /*
 507         printf("old_length=%zu new_length=%zu x=%zu len=%u len2=%u k=%u\n",
 508                old_length, new_length, x, len, len2, k);
 509         */
 510
 511         memcpy(e, s, len);
 512         e[len]   = 0xe2; /* tri-dot ellipsis: … */
 513         e[len + 1] = 0x80;
 514         e[len + 2] = 0xa6;
 515
 516         memcpy(e + len + 3, j, len2 + 1);
 517
 518         return e;
 519 }
 520
 521 char *ellipsize(const char *s, size_t length, unsigned percent) {
 522         return ellipsize_mem(s, strlen(s), length, percent);
 523 }
 524
 525 bool nulstr_contains(const char*nulstr, const char *needle) {
 526         const char *i;
 527
 528         if (!nulstr)
 529                 return false;
 530
 531         NULSTR_FOREACH(i, nulstr)
 532                 if (streq(i, needle))
 533                         return true;
 534
 535         return false;
 536 }
 537
 538 char* strshorten(char *s, size_t l) {
 539         assert(s);
 540
 541         if (l < strlen(s))
 542                 s[l] = 0;
 543
 544         return s;
 545 }
 546
 547 char *strreplace(const char *text, const char *old_string, const char *new_string) {
 548         const char *f;
 549         char *t, *r;
 550         size_t l, old_len, new_len;
 551
 552         assert(text);
 553         assert(old_string);
 554         assert(new_string);
 555
 556         old_len = strlen(old_string);
 557         new_len = strlen(new_string);
 558
 559         l = strlen(text);
 560         r = new(char, l+1);
 561         if (!r)
 562                 return NULL;
 563
 564         f = text;
 565         t = r;
 566         while (*f) {
 567                 char *a;
 568                 size_t d, nl;
 569
 570                 if (!startswith(f, old_string)) {
 571                         *(t++) = *(f++);
 572                         continue;
 573                 }
 574
 575                 d = t - r;
 576                 nl = l - old_len + new_len;
 577                 a = realloc(r, nl + 1);
 578                 if (!a)
 579                         goto oom;
 580
 581                 l = nl;
 582                 r = a;
 583                 t = r + d;
 584
 585                 t = stpcpy(t, new_string);
 586                 f += old_len;
 587         }
 588
 589         *t = 0;
 590         return r;
 591
 592 oom:
 593         free(r);
 594         return NULL;
 595 }
 596
 597 char *strip_tab_ansi(char **ibuf, size_t *_isz) {
 598         const char *i, *begin = NULL;
 599         enum {
 600                 STATE_OTHER,
 601                 STATE_ESCAPE,
 602                 STATE_BRACKET
 603         } state = STATE_OTHER;
 604         char *obuf = NULL;
 605         size_t osz = 0, isz;
 606         FILE *f;
 607
 608         assert(ibuf);
 609         assert(*ibuf);
 610
 611         /* Strips ANSI color and replaces TABs by 8 spaces */
 612
 613         isz = _isz ? *_isz : strlen(*ibuf);
 614
 615         f = open_memstream(&obuf, &osz);
 616         if (!f)
 617                 return NULL;
 618
 619         for (i = *ibuf; i < *ibuf + isz + 1; i++) {
 620
 621                 switch (state) {
 622
 623                 case STATE_OTHER:
 624                         if (i >= *ibuf + isz) /* EOT */
 625                                 break;
 626                         else if (*i == '\x1B')
 627                                 state = STATE_ESCAPE;
 628                         else if (*i == '\t')
 629                                 fputs("        ", f);
 630                         else
 631                                 fputc(*i, f);
 632                         break;
 633
 634                 case STATE_ESCAPE:
 635                         if (i >= *ibuf + isz) { /* EOT */
 636                                 fputc('\x1B', f);
 637                                 break;
 638                         } else if (*i == '[') {
 639                                 state = STATE_BRACKET;
 640                                 begin = i + 1;
 641                         } else {
 642                                 fputc('\x1B', f);
 643                                 fputc(*i, f);
 644                                 state = STATE_OTHER;
 645                         }
 646
 647                         break;
 648
 649                 case STATE_BRACKET:
 650
 651                         if (i >= *ibuf + isz || /* EOT */
 652                             (!(*i >= '0' && *i <= '9') && *i != ';' && *i != 'm')) {
 653                                 fputc('\x1B', f);
 654                                 fputc('[', f);
 655                                 state = STATE_OTHER;
 656                                 i = begin-1;
 657                         } else if (*i == 'm')
 658                                 state = STATE_OTHER;
 659                         break;
 660                 }
 661         }
 662
 663         if (ferror(f)) {
 664                 fclose(f);
 665                 free(obuf);
 666                 return NULL;
 667         }
 668
 669         fclose(f);
 670
 671         free(*ibuf);
 672         *ibuf = obuf;
 673
 674         if (_isz)
 675                 *_isz = osz;
 676
 677         return obuf;
 678 }
 679
 680 char *strextend(char **x, ...) {
 681         va_list ap;
 682         size_t f, l;
 683         char *r, *p;
 684
 685         assert(x);
 686
 687         l = f = *x ? strlen(*x) : 0;
 688
 689         va_start(ap, x);
 690         for (;;) {
 691                 const char *t;
 692                 size_t n;
 693
 694                 t = va_arg(ap, const char *);
 695                 if (!t)
 696                         break;
 697
 698                 n = strlen(t);
 699                 if (n > ((size_t) -1) - l) {
 700                         va_end(ap);
 701                         return NULL;
 702                 }
 703
 704                 l += n;
 705         }
 706         va_end(ap);
 707
 708         r = realloc(*x, l+1);
 709         if (!r)
 710                 return NULL;
 711
 712         p = r + f;
 713
 714         va_start(ap, x);
 715         for (;;) {
 716                 const char *t;
 717
 718                 t = va_arg(ap, const char *);
 719                 if (!t)
 720                         break;
 721
 722                 p = stpcpy(p, t);
 723         }
 724         va_end(ap);
 725
 726         *p = 0;
 727         *x = r;
 728
 729         return r + l;
 730 }
 731
 732 char *strrep(const char *s, unsigned n) {
 733         size_t l;
 734         char *r, *p;
 735         unsigned i;
 736
 737         assert(s);
 738
 739         l = strlen(s);
 740         p = r = malloc(l * n + 1);
 741         if (!r)
 742                 return NULL;
 743
 744         for (i = 0; i < n; i++)
 745                 p = stpcpy(p, s);
 746
 747         *p = 0;
 748         return r;
 749 }
 750
 751 int split_pair(const char *s, const char *sep, char **l, char **r) {
 752         char *x, *a, *b;
 753
 754         assert(s);
 755         assert(sep);
 756         assert(l);
 757         assert(r);
 758
 759         if (isempty(sep))
 760                 return -EINVAL;
 761
 762         x = strstr(s, sep);
 763         if (!x)
 764                 return -EINVAL;
 765
 766         a = strndup(s, x - s);
 767         if (!a)
 768                 return -ENOMEM;
 769
 770         b = strdup(x + strlen(sep));
 771         if (!b) {
 772                 free(a);
 773                 return -ENOMEM;
 774         }
 775
 776         *l = a;
 777         *r = b;
 778
 779         return 0;
 780 }
 781
 782 int free_and_strdup(char **p, const char *s) {
 783         char *t;
 784
 785         assert(p);
 786
 787         /* Replaces a string pointer with an strdup()ed new string,
 788          * possibly freeing the old one. */
 789
 790         if (streq_ptr(*p, s))
 791                 return 0;
 792
 793         if (s) {
 794                 t = strdup(s);
 795                 if (!t)
 796                         return -ENOMEM;
 797         } else
 798                 t = NULL;
 799
 800         free(*p);
 801         *p = t;
 802
 803         return 1;
 804 }
 805
 806 #pragma GCC push_options
 807 #pragma GCC optimize("O0")
 808
 809 void* memory_erase(void *p, size_t l) {
 810         volatile uint8_t* x = (volatile uint8_t*) p;
 811
 812         /* This basically does what memset() does, but hopefully isn't
 813          * optimized away by the compiler. One of those days, when
 814          * glibc learns memset_s() we should replace this call by
 815          * memset_s(), but until then this has to do. */
 816
 817         for (; l > 0; l--)
 818                 *(x++) = 'x';
 819
 820         return p;
 821 }
 822
 823 #pragma GCC pop_options
 824
 825 char* string_erase(char *x) {
 826
 827         if (!x)
 828                 return NULL;
 829
 830         /* A delicious drop of snake-oil! To be called on memory where
 831          * we stored passphrases or so, after we used them. */
 832
 833         return memory_erase(x, strlen(x));
 834 }
 835
 836 char *string_free_erase(char *s) {
 837         return mfree(string_erase(s));
 838 }
 839
 840 bool string_is_safe(const char *p) {
 841         const char *t;
 842
 843         if (!p)
 844                 return false;
 845
 846         for (t = p; *t; t++) {
 847                 if (*t > 0 && *t < ' ') /* no control characters */
 848                         return false;
 849
 850                 if (strchr(QUOTES "\\\x7f", *t))
 851                         return false;
 852         }
 853
 854         return true;
 855 }