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
   8 #include "alloc-util.h"
   9 #include "glob-util.h"
  10 #include "hexdecoct.h"
  11 #include "path-util.h"
  12 #include "special.h"
  13 #include "string-util.h"
  14 #include "strv.h"
  15 #include "unit-name.h"
  16
  17 /* Characters valid in a unit name. */
  18 #define VALID_CHARS                             \
  19         DIGITS                                  \
  20         LETTERS                                 \
  21         ":-_.\\"
  22
  23 /* The same, but also permits the single @ character that may appear */
  24 #define VALID_CHARS_WITH_AT                     \
  25         "@"                                     \
  26         VALID_CHARS
  27
  28 /* All chars valid in a unit name glob */
  29 #define VALID_CHARS_GLOB                        \
  30         VALID_CHARS_WITH_AT                     \
  31         "[]!-*?"
  32
  33 bool unit_name_is_valid(const char *n, UnitNameFlags flags) {
  34         const char *e, *i, *at;
  35
  36         assert((flags & ~(UNIT_NAME_PLAIN|UNIT_NAME_INSTANCE|UNIT_NAME_TEMPLATE)) == 0);
  37
  38         if (_unlikely_(flags == 0))
  39                 return false;
  40
  41         if (isempty(n))
  42                 return false;
  43
  44         if (strlen(n) >= UNIT_NAME_MAX)
  45                 return false;
  46
  47         e = strrchr(n, '.');
  48         if (!e || e == n)
  49                 return false;
  50
  51         if (unit_type_from_string(e + 1) < 0)
  52                 return false;
  53
  54         for (i = n, at = NULL; i < e; i++) {
  55
  56                 if (*i == '@' && !at)
  57                         at = i;
  58
  59                 if (!strchr("@" VALID_CHARS, *i))
  60                         return false;
  61         }
  62
  63         if (at == n)
  64                 return false;
  65
  66         if (flags & UNIT_NAME_PLAIN)
  67                 if (!at)
  68                         return true;
  69
  70         if (flags & UNIT_NAME_INSTANCE)
  71                 if (at && e > at + 1)
  72                         return true;
  73
  74         if (flags & UNIT_NAME_TEMPLATE)
  75                 if (at && e == at + 1)
  76                         return true;
  77
  78         return false;
  79 }
  80
  81 bool unit_prefix_is_valid(const char *p) {
  82
  83         /* We don't allow additional @ in the prefix string */
  84
  85         if (isempty(p))
  86                 return false;
  87
  88         return in_charset(p, VALID_CHARS);
  89 }
  90
  91 bool unit_instance_is_valid(const char *i) {
  92
  93         /* The max length depends on the length of the string, so we
  94          * don't really check this here. */
  95
  96         if (isempty(i))
  97                 return false;
  98
  99         /* We allow additional @ in the instance string, we do not
 100          * allow them in the prefix! */
 101
 102         return in_charset(i, "@" VALID_CHARS);
 103 }
 104
 105 bool unit_suffix_is_valid(const char *s) {
 106         if (isempty(s))
 107                 return false;
 108
 109         if (s[0] != '.')
 110                 return false;
 111
 112         if (unit_type_from_string(s + 1) < 0)
 113                 return false;
 114
 115         return true;
 116 }
 117
 118 int unit_name_to_prefix(const char *n, char **ret) {
 119         const char *p;
 120         char *s;
 121
 122         assert(n);
 123         assert(ret);
 124
 125         if (!unit_name_is_valid(n, UNIT_NAME_ANY))
 126                 return -EINVAL;
 127
 128         p = strchr(n, '@');
 129         if (!p)
 130                 p = strrchr(n, '.');
 131
 132         assert_se(p);
 133
 134         s = strndup(n, p - n);
 135         if (!s)
 136                 return -ENOMEM;
 137
 138         *ret = s;
 139         return 0;
 140 }
 141
 142 int unit_name_to_instance(const char *n, char **ret) {
 143         const char *p, *d;
 144
 145         assert(n);
 146
 147         if (!unit_name_is_valid(n, UNIT_NAME_ANY))
 148                 return -EINVAL;
 149
 150         /* Everything past the first @ and before the last . is the instance */
 151         p = strchr(n, '@');
 152         if (!p) {
 153                 if (ret)
 154                         *ret = NULL;
 155                 return UNIT_NAME_PLAIN;
 156         }
 157
 158         p++;
 159
 160         d = strrchr(p, '.');
 161         if (!d)
 162                 return -EINVAL;
 163
 164         if (ret) {
 165                 char *i = strndup(p, d-p);
 166                 if (!i)
 167                         return -ENOMEM;
 168
 169                 *ret = i;
 170         }
 171         return d > p ? UNIT_NAME_INSTANCE : UNIT_NAME_TEMPLATE;
 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         _cleanup_free_ char *s = NULL;
 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                 _cleanup_free_ char *w = NULL;
 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                         return -EINVAL;
 427
 428                 /* Prefix a slash again */
 429                 s = strjoin("/", w);
 430                 if (!s)
 431                         return -ENOMEM;
 432
 433                 if (!path_is_normalized(s))
 434                         return -EINVAL;
 435         }
 436
 437         if (ret)
 438                 *ret = TAKE_PTR(s);
 439
 440         return 0;
 441 }
 442
 443 int unit_name_replace_instance(const char *f, const char *i, char **ret) {
 444         const char *p, *e;
 445         char *s;
 446         size_t a, b;
 447
 448         assert(f);
 449         assert(i);
 450         assert(ret);
 451
 452         if (!unit_name_is_valid(f, UNIT_NAME_INSTANCE|UNIT_NAME_TEMPLATE))
 453                 return -EINVAL;
 454         if (!unit_instance_is_valid(i))
 455                 return -EINVAL;
 456
 457         assert_se(p = strchr(f, '@'));
 458         assert_se(e = strrchr(f, '.'));
 459
 460         a = p - f;
 461         b = strlen(i);
 462
 463         s = new(char, a + 1 + b + strlen(e) + 1);
 464         if (!s)
 465                 return -ENOMEM;
 466
 467         strcpy(mempcpy(mempcpy(s, f, a + 1), i, b), e);
 468
 469         *ret = s;
 470         return 0;
 471 }
 472
 473 int unit_name_template(const char *f, char **ret) {
 474         const char *p, *e;
 475         char *s;
 476         size_t a;
 477
 478         assert(f);
 479         assert(ret);
 480
 481         if (!unit_name_is_valid(f, UNIT_NAME_INSTANCE|UNIT_NAME_TEMPLATE))
 482                 return -EINVAL;
 483
 484         assert_se(p = strchr(f, '@'));
 485         assert_se(e = strrchr(f, '.'));
 486
 487         a = p - f;
 488
 489         s = new(char, a + 1 + strlen(e) + 1);
 490         if (!s)
 491                 return -ENOMEM;
 492
 493         strcpy(mempcpy(s, f, a + 1), e);
 494
 495         *ret = s;
 496         return 0;
 497 }
 498
 499 int unit_name_from_path(const char *path, const char *suffix, char **ret) {
 500         _cleanup_free_ char *p = NULL;
 501         char *s = NULL;
 502         int r;
 503
 504         assert(path);
 505         assert(suffix);
 506         assert(ret);
 507
 508         if (!unit_suffix_is_valid(suffix))
 509                 return -EINVAL;
 510
 511         r = unit_name_path_escape(path, &p);
 512         if (r < 0)
 513                 return r;
 514
 515         s = strjoin(p, suffix);
 516         if (!s)
 517                 return -ENOMEM;
 518
 519         *ret = s;
 520         return 0;
 521 }
 522
 523 int unit_name_from_path_instance(const char *prefix, const char *path, const char *suffix, char **ret) {
 524         _cleanup_free_ char *p = NULL;
 525         char *s;
 526         int r;
 527
 528         assert(prefix);
 529         assert(path);
 530         assert(suffix);
 531         assert(ret);
 532
 533         if (!unit_prefix_is_valid(prefix))
 534                 return -EINVAL;
 535
 536         if (!unit_suffix_is_valid(suffix))
 537                 return -EINVAL;
 538
 539         r = unit_name_path_escape(path, &p);
 540         if (r < 0)
 541                 return r;
 542
 543         s = strjoin(prefix, "@", p, suffix);
 544         if (!s)
 545                 return -ENOMEM;
 546
 547         *ret = s;
 548         return 0;
 549 }
 550
 551 int unit_name_to_path(const char *name, char **ret) {
 552         _cleanup_free_ char *prefix = NULL;
 553         int r;
 554
 555         assert(name);
 556
 557         r = unit_name_to_prefix(name, &prefix);
 558         if (r < 0)
 559                 return r;
 560
 561         return unit_name_path_unescape(prefix, ret);
 562 }
 563
 564 static bool do_escape_mangle(const char *f, bool allow_globs, char *t) {
 565         const char *valid_chars;
 566         bool mangled = false;
 567
 568         assert(f);
 569         assert(t);
 570
 571         /* We'll only escape the obvious characters here, to play safe.
 572          *
 573          * Returns true if any characters were mangled, false otherwise.
 574          */
 575
 576         valid_chars = allow_globs ? VALID_CHARS_GLOB : VALID_CHARS_WITH_AT;
 577
 578         for (; *f; f++)
 579                 if (*f == '/') {
 580                         *(t++) = '-';
 581                         mangled = true;
 582                 } else if (!strchr(valid_chars, *f)) {
 583                         t = do_escape_char(*f, t);
 584                         mangled = true;
 585                 } else
 586                         *(t++) = *f;
 587         *t = 0;
 588
 589         return mangled;
 590 }
 591
 592 /**
 593  *  Convert a string to a unit name. /dev/blah is converted to dev-blah.device,
 594  *  /blah/blah is converted to blah-blah.mount, anything else is left alone,
 595  *  except that @suffix is appended if a valid unit suffix is not present.
 596  *
 597  *  If @allow_globs, globs characters are preserved. Otherwise, they are escaped.
 598  */
 599 int unit_name_mangle_with_suffix(const char *name, const char *operation, UnitNameMangle flags, const char *suffix, char **ret) {
 600         char *s;
 601         int r;
 602         bool mangled, suggest_escape = true;
 603
 604         assert(name);
 605         assert(suffix);
 606         assert(ret);
 607
 608         if (isempty(name)) /* We cannot mangle empty unit names to become valid, sorry. */
 609                 return -EINVAL;
 610
 611         if (!unit_suffix_is_valid(suffix))
 612                 return -EINVAL;
 613
 614         /* Already a fully valid unit name? If so, no mangling is necessary... */
 615         if (unit_name_is_valid(name, UNIT_NAME_ANY))
 616                 goto good;
 617
 618         /* Already a fully valid globbing expression? If so, no mangling is necessary either... */
 619         if (string_is_glob(name) && in_charset(name, VALID_CHARS_GLOB)) {
 620                 if (flags & UNIT_NAME_MANGLE_GLOB)
 621                         goto good;
 622                 log_full(flags & UNIT_NAME_MANGLE_WARN ? LOG_NOTICE : LOG_DEBUG,
 623                          "Glob pattern passed%s%s, but globs are not supported for this.",
 624                          operation ? " " : "", operation ?: "");
 625                 suggest_escape = false;
 626         }
 627
 628         if (is_device_path(name)) {
 629                 r = unit_name_from_path(name, ".device", ret);
 630                 if (r >= 0)
 631                         return 1;
 632                 if (r != -EINVAL)
 633                         return r;
 634         }
 635
 636         if (path_is_absolute(name)) {
 637                 r = unit_name_from_path(name, ".mount", ret);
 638                 if (r >= 0)
 639                         return 1;
 640                 if (r != -EINVAL)
 641                         return r;
 642         }
 643
 644         s = new(char, strlen(name) * 4 + strlen(suffix) + 1);
 645         if (!s)
 646                 return -ENOMEM;
 647
 648         mangled = do_escape_mangle(name, flags & UNIT_NAME_MANGLE_GLOB, s);
 649         if (mangled)
 650                 log_full(flags & UNIT_NAME_MANGLE_WARN ? LOG_NOTICE : LOG_DEBUG,
 651                          "Invalid unit name \"%s\" escaped as \"%s\"%s.",
 652                          name, s,
 653                          suggest_escape ? " (maybe you should use systemd-escape?)" : "");
 654
 655         /* Append a suffix if it doesn't have any, but only if this is not a glob, so that we can allow
 656          * "foo.*" as a valid glob. */
 657         if ((!(flags & UNIT_NAME_MANGLE_GLOB) || !string_is_glob(s)) && unit_name_to_type(s) < 0)
 658                 strcat(s, suffix);
 659
 660         *ret = s;
 661         return 1;
 662
 663 good:
 664         s = strdup(name);
 665         if (!s)
 666                 return -ENOMEM;
 667
 668         *ret = s;
 669         return 0;
 670 }
 671
 672 bool service_unit_name_is_valid(const char *name) {
 673         _cleanup_free_ char *prefix = NULL, *s = NULL;
 674         const char *e, *service_name = name;
 675
 676         if (!unit_name_is_valid(name, UNIT_NAME_ANY))
 677                 return false;
 678
 679         e = endswith(name, ".service");
 680         if (!e)
 681                 return false;
 682
 683         /* If it's a template or instance, get the prefix as a service name. */
 684         if (unit_name_is_valid(name, UNIT_NAME_INSTANCE|UNIT_NAME_TEMPLATE)) {
 685                 if (unit_name_to_prefix(name, &prefix) < 0)
 686                         return false;
 687
 688                 s = strjoin(prefix, ".service");
 689                 if (!s)
 690                         return false;
 691
 692                 service_name = s;
 693         }
 694
 695         /* Reject reserved service name(s). */
 696         if (streq(service_name, SPECIAL_ROOT_SERVICE))
 697                 return false;
 698
 699         return true;
 700 }
 701
 702 int slice_build_parent_slice(const char *slice, char **ret) {
 703         char *s, *dash;
 704         int r;
 705
 706         assert(slice);
 707         assert(ret);
 708
 709         if (!slice_name_is_valid(slice))
 710                 return -EINVAL;
 711
 712         if (streq(slice, SPECIAL_ROOT_SLICE)) {
 713                 *ret = NULL;
 714                 return 0;
 715         }
 716
 717         s = strdup(slice);
 718         if (!s)
 719                 return -ENOMEM;
 720
 721         dash = strrchr(s, '-');
 722         if (dash)
 723                 strcpy(dash, ".slice");
 724         else {
 725                 r = free_and_strdup(&s, SPECIAL_ROOT_SLICE);
 726                 if (r < 0) {
 727                         free(s);
 728                         return r;
 729                 }
 730         }
 731
 732         *ret = s;
 733         return 1;
 734 }
 735
 736 int slice_build_subslice(const char *slice, const char *name, char **ret) {
 737         char *subslice;
 738
 739         assert(slice);
 740         assert(name);
 741         assert(ret);
 742
 743         if (!slice_name_is_valid(slice))
 744                 return -EINVAL;
 745
 746         if (!unit_prefix_is_valid(name))
 747                 return -EINVAL;
 748
 749         if (streq(slice, SPECIAL_ROOT_SLICE))
 750                 subslice = strjoin(name, ".slice");
 751         else {
 752                 char *e;
 753
 754                 assert_se(e = endswith(slice, ".slice"));
 755
 756                 subslice = new(char, (e - slice) + 1 + strlen(name) + 6 + 1);
 757                 if (!subslice)
 758                         return -ENOMEM;
 759
 760                 stpcpy(stpcpy(stpcpy(mempcpy(subslice, slice, e - slice), "-"), name), ".slice");
 761         }
 762
 763         *ret = subslice;
 764         return 0;
 765 }
 766
 767 bool slice_name_is_valid(const char *name) {
 768         const char *p, *e;
 769         bool dash = false;
 770
 771         if (!unit_name_is_valid(name, UNIT_NAME_PLAIN))
 772                 return false;
 773
 774         if (streq(name, SPECIAL_ROOT_SLICE))
 775                 return true;
 776
 777         e = endswith(name, ".slice");
 778         if (!e)
 779                 return false;
 780
 781         for (p = name; p < e; p++) {
 782
 783                 if (*p == '-') {
 784
 785                         /* Don't allow initial dash */
 786                         if (p == name)
 787                                 return false;
 788
 789                         /* Don't allow multiple dashes */
 790                         if (dash)
 791                                 return false;
 792
 793                         dash = true;
 794                 } else
 795                         dash = false;
 796         }
 797
 798         /* Don't allow trailing hash */
 799         if (dash)
 800                 return false;
 801
 802         return true;
 803 }