src/basic/unit-name.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   This file is part of systemd.
   4
   5   Copyright 2010 Lennart Poettering
   6 ***/
   7
   8 #include <errno.h>
   9 #include <stddef.h>
  10 #include <stdint.h>
  11 #include <stdlib.h>
  12 #include <string.h>
  13
  14 #include "alloc-util.h"
  15 #include "glob-util.h"
  16 #include "hexdecoct.h"
  17 #include "path-util.h"
  18 #include "special.h"
  19 #include "string-util.h"
  20 #include "strv.h"
  21 #include "unit-name.h"
  22
  23 /* Characters valid in a unit name. */
  24 #define VALID_CHARS                             \
  25         DIGITS                                  \
  26         LETTERS                                 \
  27         ":-_.\\"
  28
  29 /* The same, but also permits the single @ character that may appear */
  30 #define VALID_CHARS_WITH_AT                     \
  31         "@"                                     \
  32         VALID_CHARS
  33
  34 /* All chars valid in a unit name glob */
  35 #define VALID_CHARS_GLOB                        \
  36         VALID_CHARS_WITH_AT                     \
  37         "[]!-*?"
  38
  39 bool unit_name_is_valid(const char *n, UnitNameFlags flags) {
  40         const char *e, *i, *at;
  41
  42         assert((flags & ~(UNIT_NAME_PLAIN|UNIT_NAME_INSTANCE|UNIT_NAME_TEMPLATE)) == 0);
  43
  44         if (_unlikely_(flags == 0))
  45                 return false;
  46
  47         if (isempty(n))
  48                 return false;
  49
  50         if (strlen(n) >= UNIT_NAME_MAX)
  51                 return false;
  52
  53         e = strrchr(n, '.');
  54         if (!e || e == n)
  55                 return false;
  56
  57         if (unit_type_from_string(e + 1) < 0)
  58                 return false;
  59
  60         for (i = n, at = NULL; i < e; i++) {
  61
  62                 if (*i == '@' && !at)
  63                         at = i;
  64
  65                 if (!strchr("@" VALID_CHARS, *i))
  66                         return false;
  67         }
  68
  69         if (at == n)
  70                 return false;
  71
  72         if (flags & UNIT_NAME_PLAIN)
  73                 if (!at)
  74                         return true;
  75
  76         if (flags & UNIT_NAME_INSTANCE)
  77                 if (at && e > at + 1)
  78                         return true;
  79
  80         if (flags & UNIT_NAME_TEMPLATE)
  81                 if (at && e == at + 1)
  82                         return true;
  83
  84         return false;
  85 }
  86
  87 bool unit_prefix_is_valid(const char *p) {
  88
  89         /* We don't allow additional @ in the prefix string */
  90
  91         if (isempty(p))
  92                 return false;
  93
  94         return in_charset(p, VALID_CHARS);
  95 }
  96
  97 bool unit_instance_is_valid(const char *i) {
  98
  99         /* The max length depends on the length of the string, so we
 100          * don't really check this here. */
 101
 102         if (isempty(i))
 103                 return false;
 104
 105         /* We allow additional @ in the instance string, we do not
 106          * allow them in the prefix! */
 107
 108         return in_charset(i, "@" VALID_CHARS);
 109 }
 110
 111 bool unit_suffix_is_valid(const char *s) {
 112         if (isempty(s))
 113                 return false;
 114
 115         if (s[0] != '.')
 116                 return false;
 117
 118         if (unit_type_from_string(s + 1) < 0)
 119                 return false;
 120
 121         return true;
 122 }
 123
 124 int unit_name_to_prefix(const char *n, char **ret) {
 125         const char *p;
 126         char *s;
 127
 128         assert(n);
 129         assert(ret);
 130
 131         if (!unit_name_is_valid(n, UNIT_NAME_ANY))
 132                 return -EINVAL;
 133
 134         p = strchr(n, '@');
 135         if (!p)
 136                 p = strrchr(n, '.');
 137
 138         assert_se(p);
 139
 140         s = strndup(n, p - n);
 141         if (!s)
 142                 return -ENOMEM;
 143
 144         *ret = s;
 145         return 0;
 146 }
 147
 148 int unit_name_to_instance(const char *n, char **instance) {
 149         const char *p, *d;
 150         char *i;
 151
 152         assert(n);
 153         assert(instance);
 154
 155         if (!unit_name_is_valid(n, UNIT_NAME_ANY))
 156                 return -EINVAL;
 157
 158         /* Everything past the first @ and before the last . is the instance */
 159         p = strchr(n, '@');
 160         if (!p) {
 161                 *instance = NULL;
 162                 return 0;
 163         }
 164
 165         p++;
 166
 167         d = strrchr(p, '.');
 168         if (!d)
 169                 return -EINVAL;
 170
 171         i = strndup(p, d-p);
 172         if (!i)
 173                 return -ENOMEM;
 174
 175         *instance = i;
 176         return 1;
 177 }
 178
 179 int unit_name_to_prefix_and_instance(const char *n, char **ret) {
 180         const char *d;
 181         char *s;
 182
 183         assert(n);
 184         assert(ret);
 185
 186         if (!unit_name_is_valid(n, UNIT_NAME_ANY))
 187                 return -EINVAL;
 188
 189         d = strrchr(n, '.');
 190         if (!d)
 191                 return -EINVAL;
 192
 193         s = strndup(n, d - n);
 194         if (!s)
 195                 return -ENOMEM;
 196
 197         *ret = s;
 198         return 0;
 199 }
 200
 201 UnitType unit_name_to_type(const char *n) {
 202         const char *e;
 203
 204         assert(n);
 205
 206         if (!unit_name_is_valid(n, UNIT_NAME_ANY))
 207                 return _UNIT_TYPE_INVALID;
 208
 209         assert_se(e = strrchr(n, '.'));
 210
 211         return unit_type_from_string(e + 1);
 212 }
 213
 214 int unit_name_change_suffix(const char *n, const char *suffix, char **ret) {
 215         char *e, *s;
 216         size_t a, b;
 217
 218         assert(n);
 219         assert(suffix);
 220         assert(ret);
 221
 222         if (!unit_name_is_valid(n, UNIT_NAME_ANY))
 223                 return -EINVAL;
 224
 225         if (!unit_suffix_is_valid(suffix))
 226                 return -EINVAL;
 227
 228         assert_se(e = strrchr(n, '.'));
 229
 230         a = e - n;
 231         b = strlen(suffix);
 232
 233         s = new(char, a + b + 1);
 234         if (!s)
 235                 return -ENOMEM;
 236
 237         strcpy(mempcpy(s, n, a), suffix);
 238         *ret = s;
 239
 240         return 0;
 241 }
 242
 243 int unit_name_build(const char *prefix, const char *instance, const char *suffix, char **ret) {
 244         UnitType type;
 245
 246         assert(prefix);
 247         assert(suffix);
 248         assert(ret);
 249
 250         if (suffix[0] != '.')
 251                 return -EINVAL;
 252
 253         type = unit_type_from_string(suffix + 1);
 254         if (type < 0)
 255                 return -EINVAL;
 256
 257         return unit_name_build_from_type(prefix, instance, type, ret);
 258 }
 259
 260 int unit_name_build_from_type(const char *prefix, const char *instance, UnitType type, char **ret) {
 261         const char *ut;
 262         char *s;
 263
 264         assert(prefix);
 265         assert(type >= 0);
 266         assert(type < _UNIT_TYPE_MAX);
 267         assert(ret);
 268
 269         if (!unit_prefix_is_valid(prefix))
 270                 return -EINVAL;
 271
 272         if (instance && !unit_instance_is_valid(instance))
 273                 return -EINVAL;
 274
 275         ut = unit_type_to_string(type);
 276
 277         if (!instance)
 278                 s = strjoin(prefix, ".", ut);
 279         else
 280                 s = strjoin(prefix, "@", instance, ".", ut);
 281         if (!s)
 282                 return -ENOMEM;
 283
 284         *ret = s;
 285         return 0;
 286 }
 287
 288 static char *do_escape_char(char c, char *t) {
 289         assert(t);
 290
 291         *(t++) = '\\';
 292         *(t++) = 'x';
 293         *(t++) = hexchar(c >> 4);
 294         *(t++) = hexchar(c);
 295
 296         return t;
 297 }
 298
 299 static char *do_escape(const char *f, char *t) {
 300         assert(f);
 301         assert(t);
 302
 303         /* do not create units with a leading '.', like for "/.dotdir" mount points */
 304         if (*f == '.') {
 305                 t = do_escape_char(*f, t);
 306                 f++;
 307         }
 308
 309         for (; *f; f++) {
 310                 if (*f == '/')
 311                         *(t++) = '-';
 312                 else if (IN_SET(*f, '-', '\\') || !strchr(VALID_CHARS, *f))
 313                         t = do_escape_char(*f, t);
 314                 else
 315                         *(t++) = *f;
 316         }
 317
 318         return t;
 319 }
 320
 321 char *unit_name_escape(const char *f) {
 322         char *r, *t;
 323
 324         assert(f);
 325
 326         r = new(char, strlen(f)*4+1);
 327         if (!r)
 328                 return NULL;
 329
 330         t = do_escape(f, r);
 331         *t = 0;
 332
 333         return r;
 334 }
 335
 336 int unit_name_unescape(const char *f, char **ret) {
 337         _cleanup_free_ char *r = NULL;
 338         char *t;
 339
 340         assert(f);
 341
 342         r = strdup(f);
 343         if (!r)
 344                 return -ENOMEM;
 345
 346         for (t = r; *f; f++) {
 347                 if (*f == '-')
 348                         *(t++) = '/';
 349                 else if (*f == '\\') {
 350                         int a, b;
 351
 352                         if (f[1] != 'x')
 353                                 return -EINVAL;
 354
 355                         a = unhexchar(f[2]);
 356                         if (a < 0)
 357                                 return -EINVAL;
 358
 359                         b = unhexchar(f[3]);
 360                         if (b < 0)
 361                                 return -EINVAL;
 362
 363                         *(t++) = (char) (((uint8_t) a << 4U) | (uint8_t) b);
 364                         f += 3;
 365                 } else
 366                         *(t++) = *f;
 367         }
 368
 369         *t = 0;
 370
 371         *ret = TAKE_PTR(r);
 372
 373         return 0;
 374 }
 375
 376 int unit_name_path_escape(const char *f, char **ret) {
 377         char *p, *s;
 378
 379         assert(f);
 380         assert(ret);
 381
 382         p = strdupa(f);
 383         if (!p)
 384                 return -ENOMEM;
 385
 386         path_kill_slashes(p);
 387
 388         if (STR_IN_SET(p, "/", ""))
 389                 s = strdup("-");
 390         else {
 391                 if (!path_is_normalized(p))
 392                         return -EINVAL;
 393
 394                 /* Truncate trailing slashes */
 395                 delete_trailing_chars(p, "/");
 396
 397                 /* Truncate leading slashes */
 398                 p = skip_leading_chars(p, "/");
 399
 400                 s = unit_name_escape(p);
 401         }
 402         if (!s)
 403                 return -ENOMEM;
 404
 405         *ret = s;
 406         return 0;
 407 }
 408
 409 int unit_name_path_unescape(const char *f, char **ret) {
 410         char *s;
 411         int r;
 412
 413         assert(f);
 414
 415         if (isempty(f))
 416                 return -EINVAL;
 417
 418         if (streq(f, "-")) {
 419                 s = strdup("/");
 420                 if (!s)
 421                         return -ENOMEM;
 422         } else {
 423                 char *w;
 424
 425                 r = unit_name_unescape(f, &w);
 426                 if (r < 0)
 427                         return r;
 428
 429                 /* Don't accept trailing or leading slashes */
 430                 if (startswith(w, "/") || endswith(w, "/")) {
 431                         free(w);
 432                         return -EINVAL;
 433                 }
 434
 435                 /* Prefix a slash again */
 436                 s = strappend("/", w);
 437                 free(w);
 438                 if (!s)
 439                         return -ENOMEM;
 440
 441                 if (!path_is_normalized(s)) {
 442                         free(s);
 443                         return -EINVAL;
 444                 }
 445         }
 446
 447         if (ret)
 448                 *ret = s;
 449         else
 450                 free(s);
 451
 452         return 0;
 453 }
 454
 455 int unit_name_replace_instance(const char *f, const char *i, char **ret) {
 456         const char *p, *e;
 457         char *s;
 458         size_t a, b;
 459
 460         assert(f);
 461         assert(i);
 462         assert(ret);
 463
 464         if (!unit_name_is_valid(f, UNIT_NAME_INSTANCE|UNIT_NAME_TEMPLATE))
 465                 return -EINVAL;
 466         if (!unit_instance_is_valid(i))
 467                 return -EINVAL;
 468
 469         assert_se(p = strchr(f, '@'));
 470         assert_se(e = strrchr(f, '.'));
 471
 472         a = p - f;
 473         b = strlen(i);
 474
 475         s = new(char, a + 1 + b + strlen(e) + 1);
 476         if (!s)
 477                 return -ENOMEM;
 478
 479         strcpy(mempcpy(mempcpy(s, f, a + 1), i, b), e);
 480
 481         *ret = s;
 482         return 0;
 483 }
 484
 485 int unit_name_template(const char *f, char **ret) {
 486         const char *p, *e;
 487         char *s;
 488         size_t a;
 489
 490         assert(f);
 491         assert(ret);
 492
 493         if (!unit_name_is_valid(f, UNIT_NAME_INSTANCE|UNIT_NAME_TEMPLATE))
 494                 return -EINVAL;
 495
 496         assert_se(p = strchr(f, '@'));
 497         assert_se(e = strrchr(f, '.'));
 498
 499         a = p - f;
 500
 501         s = new(char, a + 1 + strlen(e) + 1);
 502         if (!s)
 503                 return -ENOMEM;
 504
 505         strcpy(mempcpy(s, f, a + 1), e);
 506
 507         *ret = s;
 508         return 0;
 509 }
 510
 511 int unit_name_from_path(const char *path, const char *suffix, char **ret) {
 512         _cleanup_free_ char *p = NULL;
 513         char *s = NULL;
 514         int r;
 515
 516         assert(path);
 517         assert(suffix);
 518         assert(ret);
 519
 520         if (!unit_suffix_is_valid(suffix))
 521                 return -EINVAL;
 522
 523         r = unit_name_path_escape(path, &p);
 524         if (r < 0)
 525                 return r;
 526
 527         s = strappend(p, suffix);
 528         if (!s)
 529                 return -ENOMEM;
 530
 531         *ret = s;
 532         return 0;
 533 }
 534
 535 int unit_name_from_path_instance(const char *prefix, const char *path, const char *suffix, char **ret) {
 536         _cleanup_free_ char *p = NULL;
 537         char *s;
 538         int r;
 539
 540         assert(prefix);
 541         assert(path);
 542         assert(suffix);
 543         assert(ret);
 544
 545         if (!unit_prefix_is_valid(prefix))
 546                 return -EINVAL;
 547
 548         if (!unit_suffix_is_valid(suffix))
 549                 return -EINVAL;
 550
 551         r = unit_name_path_escape(path, &p);
 552         if (r < 0)
 553                 return r;
 554
 555         s = strjoin(prefix, "@", p, suffix);
 556         if (!s)
 557                 return -ENOMEM;
 558
 559         *ret = s;
 560         return 0;
 561 }
 562
 563 int unit_name_to_path(const char *name, char **ret) {
 564         _cleanup_free_ char *prefix = NULL;
 565         int r;
 566
 567         assert(name);
 568
 569         r = unit_name_to_prefix(name, &prefix);
 570         if (r < 0)
 571                 return r;
 572
 573         return unit_name_path_unescape(prefix, ret);
 574 }
 575
 576 static bool do_escape_mangle(const char *f, bool allow_globs, char *t) {
 577         const char *valid_chars;
 578         bool mangled = false;
 579
 580         assert(f);
 581         assert(t);
 582
 583         /* We'll only escape the obvious characters here, to play safe.
 584          *
 585          * Returns true if any characters were mangled, false otherwise.
 586          */
 587
 588         valid_chars = allow_globs ? VALID_CHARS_GLOB : VALID_CHARS_WITH_AT;
 589
 590         for (; *f; f++)
 591                 if (*f == '/') {
 592                         *(t++) = '-';
 593                         mangled = true;
 594                 } else if (!strchr(valid_chars, *f)) {
 595                         t = do_escape_char(*f, t);
 596                         mangled = true;
 597                 } else
 598                         *(t++) = *f;
 599         *t = 0;
 600
 601         return mangled;
 602 }
 603
 604 /**
 605  *  Convert a string to a unit name. /dev/blah is converted to dev-blah.device,
 606  *  /blah/blah is converted to blah-blah.mount, anything else is left alone,
 607  *  except that @suffix is appended if a valid unit suffix is not present.
 608  *
 609  *  If @allow_globs, globs characters are preserved. Otherwise, they are escaped.
 610  */
 611 int unit_name_mangle_with_suffix(const char *name, UnitNameMangle flags, const char *suffix, char **ret) {
 612         char *s;
 613         int r;
 614         bool mangled;
 615
 616         assert(name);
 617         assert(suffix);
 618         assert(ret);
 619
 620         if (isempty(name)) /* We cannot mangle empty unit names to become valid, sorry. */
 621                 return -EINVAL;
 622
 623         if (!unit_suffix_is_valid(suffix))
 624                 return -EINVAL;
 625
 626         /* Already a fully valid unit name? If so, no mangling is necessary... */
 627         if (unit_name_is_valid(name, UNIT_NAME_ANY))
 628                 goto good;
 629
 630         /* Already a fully valid globbing expression? If so, no mangling is necessary either... */
 631         if ((flags & UNIT_NAME_MANGLE_GLOB) &&
 632             string_is_glob(name) &&
 633             in_charset(name, VALID_CHARS_GLOB))
 634                 goto good;
 635
 636         if (is_device_path(name)) {
 637                 r = unit_name_from_path(name, ".device", ret);
 638                 if (r >= 0)
 639                         return 1;
 640                 if (r != -EINVAL)
 641                         return r;
 642         }
 643
 644         if (path_is_absolute(name)) {
 645                 r = unit_name_from_path(name, ".mount", ret);
 646                 if (r >= 0)
 647                         return 1;
 648                 if (r != -EINVAL)
 649                         return r;
 650         }
 651
 652         s = new(char, strlen(name) * 4 + strlen(suffix) + 1);
 653         if (!s)
 654                 return -ENOMEM;
 655
 656         mangled = do_escape_mangle(name, flags & UNIT_NAME_MANGLE_GLOB, s);
 657         if (mangled)
 658                 log_full(flags & UNIT_NAME_MANGLE_WARN ? LOG_NOTICE : LOG_DEBUG,
 659                          "Invalid unit name \"%s\" was escaped as \"%s\" (maybe you should use systemd-escape?)",
 660                          name, s);
 661
 662         /* 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
 663          * valid glob. */
 664         if ((!(flags & UNIT_NAME_MANGLE_GLOB) || !string_is_glob(s)) && unit_name_to_type(s) < 0)
 665                 strcat(s, suffix);
 666
 667         *ret = s;
 668         return 1;
 669
 670 good:
 671         s = strdup(name);
 672         if (!s)
 673                 return -ENOMEM;
 674
 675         *ret = s;
 676         return 0;
 677 }
 678
 679 int slice_build_parent_slice(const char *slice, char **ret) {
 680         char *s, *dash;
 681         int r;
 682
 683         assert(slice);
 684         assert(ret);
 685
 686         if (!slice_name_is_valid(slice))
 687                 return -EINVAL;
 688
 689         if (streq(slice, SPECIAL_ROOT_SLICE)) {
 690                 *ret = NULL;
 691                 return 0;
 692         }
 693
 694         s = strdup(slice);
 695         if (!s)
 696                 return -ENOMEM;
 697
 698         dash = strrchr(s, '-');
 699         if (dash)
 700                 strcpy(dash, ".slice");
 701         else {
 702                 r = free_and_strdup(&s, SPECIAL_ROOT_SLICE);
 703                 if (r < 0) {
 704                         free(s);
 705                         return r;
 706                 }
 707         }
 708
 709         *ret = s;
 710         return 1;
 711 }
 712
 713 int slice_build_subslice(const char *slice, const char*name, char **ret) {
 714         char *subslice;
 715
 716         assert(slice);
 717         assert(name);
 718         assert(ret);
 719
 720         if (!slice_name_is_valid(slice))
 721                 return -EINVAL;
 722
 723         if (!unit_prefix_is_valid(name))
 724                 return -EINVAL;
 725
 726         if (streq(slice, SPECIAL_ROOT_SLICE))
 727                 subslice = strappend(name, ".slice");
 728         else {
 729                 char *e;
 730
 731                 assert_se(e = endswith(slice, ".slice"));
 732
 733                 subslice = new(char, (e - slice) + 1 + strlen(name) + 6 + 1);
 734                 if (!subslice)
 735                         return -ENOMEM;
 736
 737                 stpcpy(stpcpy(stpcpy(mempcpy(subslice, slice, e - slice), "-"), name), ".slice");
 738         }
 739
 740         *ret = subslice;
 741         return 0;
 742 }
 743
 744 bool slice_name_is_valid(const char *name) {
 745         const char *p, *e;
 746         bool dash = false;
 747
 748         if (!unit_name_is_valid(name, UNIT_NAME_PLAIN))
 749                 return false;
 750
 751         if (streq(name, SPECIAL_ROOT_SLICE))
 752                 return true;
 753
 754         e = endswith(name, ".slice");
 755         if (!e)
 756                 return false;
 757
 758         for (p = name; p < e; p++) {
 759
 760                 if (*p == '-') {
 761
 762                         /* Don't allow initial dash */
 763                         if (p == name)
 764                                 return false;
 765
 766                         /* Don't allow multiple dashes */
 767                         if (dash)
 768                                 return false;
 769
 770                         dash = true;
 771                 } else
 772                         dash = false;
 773         }
 774
 775         /* Don't allow trailing hash */
 776         if (dash)
 777                 return false;
 778
 779         return true;
 780 }