src/basic/unit-name.c

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