src/basic/unit-name.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 <stddef.h>
  22 #include <stdint.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25
  26 #include "alloc-util.h"
  27 #include "glob-util.h"
  28 #include "hexdecoct.h"
  29 #include "path-util.h"
  30 #include "string-util.h"
  31 #include "strv.h"
  32 #include "unit-name.h"
  33
  34 /* Characters valid in a unit name. */
  35 #define VALID_CHARS                             \
  36         DIGITS                                  \
  37         LETTERS                                 \
  38         ":-_.\\"
  39
  40 /* The same, but also permits the single @ character that may appear */
  41 #define VALID_CHARS_WITH_AT                     \
  42         "@"                                     \
  43         VALID_CHARS
  44
  45 /* All chars valid in a unit name glob */
  46 #define VALID_CHARS_GLOB                        \
  47         VALID_CHARS_WITH_AT                     \
  48         "[]!-*?"
  49
  50 bool unit_name_is_valid(const char *n, UnitNameFlags flags) {
  51         const char *e, *i, *at;
  52
  53         assert((flags & ~(UNIT_NAME_PLAIN|UNIT_NAME_INSTANCE|UNIT_NAME_TEMPLATE)) == 0);
  54
  55         if (_unlikely_(flags == 0))
  56                 return false;
  57
  58         if (isempty(n))
  59                 return false;
  60
  61         if (strlen(n) >= UNIT_NAME_MAX)
  62                 return false;
  63
  64         e = strrchr(n, '.');
  65         if (!e || e == n)
  66                 return false;
  67
  68         if (unit_type_from_string(e + 1) < 0)
  69                 return false;
  70
  71         for (i = n, at = NULL; i < e; i++) {
  72
  73                 if (*i == '@' && !at)
  74                         at = i;
  75
  76                 if (!strchr("@" VALID_CHARS, *i))
  77                         return false;
  78         }
  79
  80         if (at == n)
  81                 return false;
  82
  83         if (flags & UNIT_NAME_PLAIN)
  84                 if (!at)
  85                         return true;
  86
  87         if (flags & UNIT_NAME_INSTANCE)
  88                 if (at && e > at + 1)
  89                         return true;
  90
  91         if (flags & UNIT_NAME_TEMPLATE)
  92                 if (at && e == at + 1)
  93                         return true;
  94
  95         return false;
  96 }
  97
  98 bool unit_prefix_is_valid(const char *p) {
  99
 100         /* We don't allow additional @ in the prefix string */
 101
 102         if (isempty(p))
 103                 return false;
 104
 105         return in_charset(p, VALID_CHARS);
 106 }
 107
 108 bool unit_instance_is_valid(const char *i) {
 109
 110         /* The max length depends on the length of the string, so we
 111          * don't really check this here. */
 112
 113         if (isempty(i))
 114                 return false;
 115
 116         /* We allow additional @ in the instance string, we do not
 117          * allow them in the prefix! */
 118
 119         return in_charset(i, "@" VALID_CHARS);
 120 }
 121
 122 bool unit_suffix_is_valid(const char *s) {
 123         if (isempty(s))
 124                 return false;
 125
 126         if (s[0] != '.')
 127                 return false;
 128
 129         if (unit_type_from_string(s + 1) < 0)
 130                 return false;
 131
 132         return true;
 133 }
 134
 135 int unit_name_to_prefix(const char *n, char **ret) {
 136         const char *p;
 137         char *s;
 138
 139         assert(n);
 140         assert(ret);
 141
 142         if (!unit_name_is_valid(n, UNIT_NAME_ANY))
 143                 return -EINVAL;
 144
 145         p = strchr(n, '@');
 146         if (!p)
 147                 p = strrchr(n, '.');
 148
 149         assert_se(p);
 150
 151         s = strndup(n, p - n);
 152         if (!s)
 153                 return -ENOMEM;
 154
 155         *ret = s;
 156         return 0;
 157 }
 158
 159 int unit_name_to_instance(const char *n, char **instance) {
 160         const char *p, *d;
 161         char *i;
 162
 163         assert(n);
 164         assert(instance);
 165
 166         if (!unit_name_is_valid(n, UNIT_NAME_ANY))
 167                 return -EINVAL;
 168
 169         /* Everything past the first @ and before the last . is the instance */
 170         p = strchr(n, '@');
 171         if (!p) {
 172                 *instance = NULL;
 173                 return 0;
 174         }
 175
 176         p++;
 177
 178         d = strrchr(p, '.');
 179         if (!d)
 180                 return -EINVAL;
 181
 182         i = strndup(p, d-p);
 183         if (!i)
 184                 return -ENOMEM;
 185
 186         *instance = i;
 187         return 1;
 188 }
 189
 190 int unit_name_to_prefix_and_instance(const char *n, char **ret) {
 191         const char *d;
 192         char *s;
 193
 194         assert(n);
 195         assert(ret);
 196
 197         if (!unit_name_is_valid(n, UNIT_NAME_ANY))
 198                 return -EINVAL;
 199
 200         d = strrchr(n, '.');
 201         if (!d)
 202                 return -EINVAL;
 203
 204         s = strndup(n, d - n);
 205         if (!s)
 206                 return -ENOMEM;
 207
 208         *ret = s;
 209         return 0;
 210 }
 211
 212 UnitType unit_name_to_type(const char *n) {
 213         const char *e;
 214
 215         assert(n);
 216
 217         if (!unit_name_is_valid(n, UNIT_NAME_ANY))
 218                 return _UNIT_TYPE_INVALID;
 219
 220         assert_se(e = strrchr(n, '.'));
 221
 222         return unit_type_from_string(e + 1);
 223 }
 224
 225 int unit_name_change_suffix(const char *n, const char *suffix, char **ret) {
 226         char *e, *s;
 227         size_t a, b;
 228
 229         assert(n);
 230         assert(suffix);
 231         assert(ret);
 232
 233         if (!unit_name_is_valid(n, UNIT_NAME_ANY))
 234                 return -EINVAL;
 235
 236         if (!unit_suffix_is_valid(suffix))
 237                 return -EINVAL;
 238
 239         assert_se(e = strrchr(n, '.'));
 240
 241         a = e - n;
 242         b = strlen(suffix);
 243
 244         s = new(char, a + b + 1);
 245         if (!s)
 246                 return -ENOMEM;
 247
 248         strcpy(mempcpy(s, n, a), suffix);
 249         *ret = s;
 250
 251         return 0;
 252 }
 253
 254 int unit_name_build(const char *prefix, const char *instance, const char *suffix, char **ret) {
 255         char *s;
 256
 257         assert(prefix);
 258         assert(suffix);
 259         assert(ret);
 260
 261         if (!unit_prefix_is_valid(prefix))
 262                 return -EINVAL;
 263
 264         if (instance && !unit_instance_is_valid(instance))
 265                 return -EINVAL;
 266
 267         if (!unit_suffix_is_valid(suffix))
 268                 return -EINVAL;
 269
 270         if (!instance)
 271                 s = strappend(prefix, suffix);
 272         else
 273                 s = strjoin(prefix, "@", instance, suffix);
 274         if (!s)
 275                 return -ENOMEM;
 276
 277         *ret = s;
 278         return 0;
 279 }
 280
 281 static char *do_escape_char(char c, char *t) {
 282         assert(t);
 283
 284         *(t++) = '\\';
 285         *(t++) = 'x';
 286         *(t++) = hexchar(c >> 4);
 287         *(t++) = hexchar(c);
 288
 289         return t;
 290 }
 291
 292 static char *do_escape(const char *f, char *t) {
 293         assert(f);
 294         assert(t);
 295
 296         /* do not create units with a leading '.', like for "/.dotdir" mount points */
 297         if (*f == '.') {
 298                 t = do_escape_char(*f, t);
 299                 f++;
 300         }
 301
 302         for (; *f; f++) {
 303                 if (*f == '/')
 304                         *(t++) = '-';
 305                 else if (IN_SET(*f, '-', '\\') || !strchr(VALID_CHARS, *f))
 306                         t = do_escape_char(*f, t);
 307                 else
 308                         *(t++) = *f;
 309         }
 310
 311         return t;
 312 }
 313
 314 char *unit_name_escape(const char *f) {
 315         char *r, *t;
 316
 317         assert(f);
 318
 319         r = new(char, strlen(f)*4+1);
 320         if (!r)
 321                 return NULL;
 322
 323         t = do_escape(f, r);
 324         *t = 0;
 325
 326         return r;
 327 }
 328
 329 int unit_name_unescape(const char *f, char **ret) {
 330         _cleanup_free_ char *r = NULL;
 331         char *t;
 332
 333         assert(f);
 334
 335         r = strdup(f);
 336         if (!r)
 337                 return -ENOMEM;
 338
 339         for (t = r; *f; f++) {
 340                 if (*f == '-')
 341                         *(t++) = '/';
 342                 else if (*f == '\\') {
 343                         int a, b;
 344
 345                         if (f[1] != 'x')
 346                                 return -EINVAL;
 347
 348                         a = unhexchar(f[2]);
 349                         if (a < 0)
 350                                 return -EINVAL;
 351
 352                         b = unhexchar(f[3]);
 353                         if (b < 0)
 354                                 return -EINVAL;
 355
 356                         *(t++) = (char) (((uint8_t) a << 4U) | (uint8_t) b);
 357                         f += 3;
 358                 } else
 359                         *(t++) = *f;
 360         }
 361
 362         *t = 0;
 363
 364         *ret = r;
 365         r = NULL;
 366
 367         return 0;
 368 }
 369
 370 int unit_name_path_escape(const char *f, char **ret) {
 371         char *p, *s;
 372
 373         assert(f);
 374         assert(ret);
 375
 376         p = strdupa(f);
 377         if (!p)
 378                 return -ENOMEM;
 379
 380         path_kill_slashes(p);
 381
 382         if (STR_IN_SET(p, "/", ""))
 383                 s = strdup("-");
 384         else {
 385                 if (!path_is_normalized(p))
 386                         return -EINVAL;
 387
 388                 /* Truncate trailing slashes */
 389                 delete_trailing_chars(p, "/");
 390
 391                 /* Truncate leading slashes */
 392                 p = skip_leading_chars(p, "/");
 393
 394                 s = unit_name_escape(p);
 395         }
 396         if (!s)
 397                 return -ENOMEM;
 398
 399         *ret = s;
 400         return 0;
 401 }
 402
 403 int unit_name_path_unescape(const char *f, char **ret) {
 404         char *s;
 405         int r;
 406
 407         assert(f);
 408
 409         if (isempty(f))
 410                 return -EINVAL;
 411
 412         if (streq(f, "-")) {
 413                 s = strdup("/");
 414                 if (!s)
 415                         return -ENOMEM;
 416         } else {
 417                 char *w;
 418
 419                 r = unit_name_unescape(f, &w);
 420                 if (r < 0)
 421                         return r;
 422
 423                 /* Don't accept trailing or leading slashes */
 424                 if (startswith(w, "/") || endswith(w, "/")) {
 425                         free(w);
 426                         return -EINVAL;
 427                 }
 428
 429                 /* Prefix a slash again */
 430                 s = strappend("/", w);
 431                 free(w);
 432                 if (!s)
 433                         return -ENOMEM;
 434
 435                 if (!path_is_normalized(s)) {
 436                         free(s);
 437                         return -EINVAL;
 438                 }
 439         }
 440
 441         if (ret)
 442                 *ret = s;
 443         else
 444                 free(s);
 445
 446         return 0;
 447 }
 448
 449 int unit_name_replace_instance(const char *f, const char *i, char **ret) {
 450         const char *p, *e;
 451         char *s;
 452         size_t a, b;
 453
 454         assert(f);
 455         assert(i);
 456         assert(ret);
 457
 458         if (!unit_name_is_valid(f, UNIT_NAME_INSTANCE|UNIT_NAME_TEMPLATE))
 459                 return -EINVAL;
 460         if (!unit_instance_is_valid(i))
 461                 return -EINVAL;
 462
 463         assert_se(p = strchr(f, '@'));
 464         assert_se(e = strrchr(f, '.'));
 465
 466         a = p - f;
 467         b = strlen(i);
 468
 469         s = new(char, a + 1 + b + strlen(e) + 1);
 470         if (!s)
 471                 return -ENOMEM;
 472
 473         strcpy(mempcpy(mempcpy(s, f, a + 1), i, b), e);
 474
 475         *ret = s;
 476         return 0;
 477 }
 478
 479 int unit_name_template(const char *f, char **ret) {
 480         const char *p, *e;
 481         char *s;
 482         size_t a;
 483
 484         assert(f);
 485         assert(ret);
 486
 487         if (!unit_name_is_valid(f, UNIT_NAME_INSTANCE|UNIT_NAME_TEMPLATE))
 488                 return -EINVAL;
 489
 490         assert_se(p = strchr(f, '@'));
 491         assert_se(e = strrchr(f, '.'));
 492
 493         a = p - f;
 494
 495         s = new(char, a + 1 + strlen(e) + 1);
 496         if (!s)
 497                 return -ENOMEM;
 498
 499         strcpy(mempcpy(s, f, a + 1), e);
 500
 501         *ret = s;
 502         return 0;
 503 }
 504
 505 int unit_name_from_path(const char *path, const char *suffix, char **ret) {
 506         _cleanup_free_ char *p = NULL;
 507         char *s = NULL;
 508         int r;
 509
 510         assert(path);
 511         assert(suffix);
 512         assert(ret);
 513
 514         if (!unit_suffix_is_valid(suffix))
 515                 return -EINVAL;
 516
 517         r = unit_name_path_escape(path, &p);
 518         if (r < 0)
 519                 return r;
 520
 521         s = strappend(p, suffix);
 522         if (!s)
 523                 return -ENOMEM;
 524
 525         *ret = s;
 526         return 0;
 527 }
 528
 529 int unit_name_from_path_instance(const char *prefix, const char *path, const char *suffix, char **ret) {
 530         _cleanup_free_ char *p = NULL;
 531         char *s;
 532         int r;
 533
 534         assert(prefix);
 535         assert(path);
 536         assert(suffix);
 537         assert(ret);
 538
 539         if (!unit_prefix_is_valid(prefix))
 540                 return -EINVAL;
 541
 542         if (!unit_suffix_is_valid(suffix))
 543                 return -EINVAL;
 544
 545         r = unit_name_path_escape(path, &p);
 546         if (r < 0)
 547                 return r;
 548
 549         s = strjoin(prefix, "@", p, suffix);
 550         if (!s)
 551                 return -ENOMEM;
 552
 553         *ret = s;
 554         return 0;
 555 }
 556
 557 int unit_name_to_path(const char *name, char **ret) {
 558         _cleanup_free_ char *prefix = NULL;
 559         int r;
 560
 561         assert(name);
 562
 563         r = unit_name_to_prefix(name, &prefix);
 564         if (r < 0)
 565                 return r;
 566
 567         return unit_name_path_unescape(prefix, ret);
 568 }
 569
 570 static char *do_escape_mangle(const char *f, UnitNameMangle allow_globs, char *t) {
 571         const char *valid_chars;
 572
 573         assert(f);
 574         assert(IN_SET(allow_globs, UNIT_NAME_GLOB, UNIT_NAME_NOGLOB));
 575         assert(t);
 576
 577         /* We'll only escape the obvious characters here, to play
 578          * safe. */
 579
 580         valid_chars = allow_globs == UNIT_NAME_GLOB ? VALID_CHARS_GLOB : VALID_CHARS_WITH_AT;
 581
 582         for (; *f; f++) {
 583                 if (*f == '/')
 584                         *(t++) = '-';
 585                 else if (!strchr(valid_chars, *f))
 586                         t = do_escape_char(*f, t);
 587                 else
 588                         *(t++) = *f;
 589         }
 590
 591         return t;
 592 }
 593
 594 /**
 595  *  Convert a string to a unit name. /dev/blah is converted to dev-blah.device,
 596  *  /blah/blah is converted to blah-blah.mount, anything else is left alone,
 597  *  except that @suffix is appended if a valid unit suffix is not present.
 598  *
 599  *  If @allow_globs, globs characters are preserved. Otherwise, they are escaped.
 600  */
 601 int unit_name_mangle_with_suffix(const char *name, UnitNameMangle allow_globs, const char *suffix, char **ret) {
 602         char *s, *t;
 603         int r;
 604
 605         assert(name);
 606         assert(suffix);
 607         assert(ret);
 608
 609         if (isempty(name)) /* We cannot mangle empty unit names to become valid, sorry. */
 610                 return -EINVAL;
 611
 612         if (!unit_suffix_is_valid(suffix))
 613                 return -EINVAL;
 614
 615         /* Already a fully valid unit name? If so, no mangling is necessary... */
 616         if (unit_name_is_valid(name, UNIT_NAME_ANY))
 617                 goto good;
 618
 619         /* Already a fully valid globbing expression? If so, no mangling is necessary either... */
 620         if (allow_globs == UNIT_NAME_GLOB &&
 621             string_is_glob(name) &&
 622             in_charset(name, VALID_CHARS_GLOB))
 623                 goto good;
 624
 625         if (is_device_path(name)) {
 626                 r = unit_name_from_path(name, ".device", ret);
 627                 if (r >= 0)
 628                         return 1;
 629                 if (r != -EINVAL)
 630                         return r;
 631         }
 632
 633         if (path_is_absolute(name)) {
 634                 r = unit_name_from_path(name, ".mount", ret);
 635                 if (r >= 0)
 636                         return 1;
 637                 if (r != -EINVAL)
 638                         return r;
 639         }
 640
 641         s = new(char, strlen(name) * 4 + strlen(suffix) + 1);
 642         if (!s)
 643                 return -ENOMEM;
 644
 645         t = do_escape_mangle(name, allow_globs, s);
 646         *t = 0;
 647
 648         /* Append a suffix if it doesn't have any, but only if this is not a glob, so that we can allow "foo.*" as a
 649          * valid glob. */
 650         if ((allow_globs != UNIT_NAME_GLOB || !string_is_glob(s)) && unit_name_to_type(s) < 0)
 651                 strcpy(t, suffix);
 652
 653         *ret = s;
 654         return 1;
 655
 656 good:
 657         s = strdup(name);
 658         if (!s)
 659                 return -ENOMEM;
 660
 661         *ret = s;
 662         return 0;
 663 }
 664
 665 int slice_build_parent_slice(const char *slice, char **ret) {
 666         char *s, *dash;
 667         int r;
 668
 669         assert(slice);
 670         assert(ret);
 671
 672         if (!slice_name_is_valid(slice))
 673                 return -EINVAL;
 674
 675         if (streq(slice, "-.slice")) {
 676                 *ret = NULL;
 677                 return 0;
 678         }
 679
 680         s = strdup(slice);
 681         if (!s)
 682                 return -ENOMEM;
 683
 684         dash = strrchr(s, '-');
 685         if (dash)
 686                 strcpy(dash, ".slice");
 687         else {
 688                 r = free_and_strdup(&s, "-.slice");
 689                 if (r < 0) {
 690                         free(s);
 691                         return r;
 692                 }
 693         }
 694
 695         *ret = s;
 696         return 1;
 697 }
 698
 699 int slice_build_subslice(const char *slice, const char*name, char **ret) {
 700         char *subslice;
 701
 702         assert(slice);
 703         assert(name);
 704         assert(ret);
 705
 706         if (!slice_name_is_valid(slice))
 707                 return -EINVAL;
 708
 709         if (!unit_prefix_is_valid(name))
 710                 return -EINVAL;
 711
 712         if (streq(slice, "-.slice"))
 713                 subslice = strappend(name, ".slice");
 714         else {
 715                 char *e;
 716
 717                 assert_se(e = endswith(slice, ".slice"));
 718
 719                 subslice = new(char, (e - slice) + 1 + strlen(name) + 6 + 1);
 720                 if (!subslice)
 721                         return -ENOMEM;
 722
 723                 stpcpy(stpcpy(stpcpy(mempcpy(subslice, slice, e - slice), "-"), name), ".slice");
 724         }
 725
 726         *ret = subslice;
 727         return 0;
 728 }
 729
 730 bool slice_name_is_valid(const char *name) {
 731         const char *p, *e;
 732         bool dash = false;
 733
 734         if (!unit_name_is_valid(name, UNIT_NAME_PLAIN))
 735                 return false;
 736
 737         if (streq(name, "-.slice"))
 738                 return true;
 739
 740         e = endswith(name, ".slice");
 741         if (!e)
 742                 return false;
 743
 744         for (p = name; p < e; p++) {
 745
 746                 if (*p == '-') {
 747
 748                         /* Don't allow initial dash */
 749                         if (p == name)
 750                                 return false;
 751
 752                         /* Don't allow multiple dashes */
 753                         if (dash)
 754                                 return false;
 755
 756                         dash = true;
 757                 } else
 758                         dash = false;
 759         }
 760
 761         /* Don't allow trailing hash */
 762         if (dash)
 763                 return false;
 764
 765         return true;
 766 }