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 (isempty(suffix))
 251                 return -EINVAL;
 252         if (suffix[0] != '.')
 253                 return -EINVAL;
 254
 255         type = unit_type_from_string(suffix + 1);
 256         if (type < 0)
 257                 return -EINVAL;
 258
 259         return unit_name_build_from_type(prefix, instance, type, ret);
 260 }
 261
 262 int unit_name_build_from_type(const char *prefix, const char *instance, UnitType type, char **ret) {
 263         const char *ut;
 264         char *s;
 265
 266         assert(prefix);
 267         assert(type >= 0);
 268         assert(type < _UNIT_TYPE_MAX);
 269         assert(ret);
 270
 271         if (!unit_prefix_is_valid(prefix))
 272                 return -EINVAL;
 273
 274         if (instance && !unit_instance_is_valid(instance))
 275                 return -EINVAL;
 276
 277         ut = unit_type_to_string(type);
 278
 279         if (!instance)
 280                 s = strjoin(prefix, ".", ut);
 281         else
 282                 s = strjoin(prefix, "@", instance, ".", ut);
 283         if (!s)
 284                 return -ENOMEM;
 285
 286         *ret = s;
 287         return 0;
 288 }
 289
 290 static char *do_escape_char(char c, char *t) {
 291         assert(t);
 292
 293         *(t++) = '\\';
 294         *(t++) = 'x';
 295         *(t++) = hexchar(c >> 4);
 296         *(t++) = hexchar(c);
 297
 298         return t;
 299 }
 300
 301 static char *do_escape(const char *f, char *t) {
 302         assert(f);
 303         assert(t);
 304
 305         /* do not create units with a leading '.', like for "/.dotdir" mount points */
 306         if (*f == '.') {
 307                 t = do_escape_char(*f, t);
 308                 f++;
 309         }
 310
 311         for (; *f; f++) {
 312                 if (*f == '/')
 313                         *(t++) = '-';
 314                 else if (IN_SET(*f, '-', '\\') || !strchr(VALID_CHARS, *f))
 315                         t = do_escape_char(*f, t);
 316                 else
 317                         *(t++) = *f;
 318         }
 319
 320         return t;
 321 }
 322
 323 char *unit_name_escape(const char *f) {
 324         char *r, *t;
 325
 326         assert(f);
 327
 328         r = new(char, strlen(f)*4+1);
 329         if (!r)
 330                 return NULL;
 331
 332         t = do_escape(f, r);
 333         *t = 0;
 334
 335         return r;
 336 }
 337
 338 int unit_name_unescape(const char *f, char **ret) {
 339         _cleanup_free_ char *r = NULL;
 340         char *t;
 341
 342         assert(f);
 343
 344         r = strdup(f);
 345         if (!r)
 346                 return -ENOMEM;
 347
 348         for (t = r; *f; f++) {
 349                 if (*f == '-')
 350                         *(t++) = '/';
 351                 else if (*f == '\\') {
 352                         int a, b;
 353
 354                         if (f[1] != 'x')
 355                                 return -EINVAL;
 356
 357                         a = unhexchar(f[2]);
 358                         if (a < 0)
 359                                 return -EINVAL;
 360
 361                         b = unhexchar(f[3]);
 362                         if (b < 0)
 363                                 return -EINVAL;
 364
 365                         *(t++) = (char) (((uint8_t) a << 4U) | (uint8_t) b);
 366                         f += 3;
 367                 } else
 368                         *(t++) = *f;
 369         }
 370
 371         *t = 0;
 372
 373         *ret = TAKE_PTR(r);
 374
 375         return 0;
 376 }
 377
 378 int unit_name_path_escape(const char *f, char **ret) {
 379         char *p, *s;
 380
 381         assert(f);
 382         assert(ret);
 383
 384         p = strdupa(f);
 385         if (!p)
 386                 return -ENOMEM;
 387
 388         path_kill_slashes(p);
 389
 390         if (STR_IN_SET(p, "/", ""))
 391                 s = strdup("-");
 392         else {
 393                 if (!path_is_normalized(p))
 394                         return -EINVAL;
 395
 396                 /* Truncate trailing slashes */
 397                 delete_trailing_chars(p, "/");
 398
 399                 /* Truncate leading slashes */
 400                 p = skip_leading_chars(p, "/");
 401
 402                 s = unit_name_escape(p);
 403         }
 404         if (!s)
 405                 return -ENOMEM;
 406
 407         *ret = s;
 408         return 0;
 409 }
 410
 411 int unit_name_path_unescape(const char *f, char **ret) {
 412         char *s;
 413         int r;
 414
 415         assert(f);
 416
 417         if (isempty(f))
 418                 return -EINVAL;
 419
 420         if (streq(f, "-")) {
 421                 s = strdup("/");
 422                 if (!s)
 423                         return -ENOMEM;
 424         } else {
 425                 char *w;
 426
 427                 r = unit_name_unescape(f, &w);
 428                 if (r < 0)
 429                         return r;
 430
 431                 /* Don't accept trailing or leading slashes */
 432                 if (startswith(w, "/") || endswith(w, "/")) {
 433                         free(w);
 434                         return -EINVAL;
 435                 }
 436
 437                 /* Prefix a slash again */
 438                 s = strappend("/", w);
 439                 free(w);
 440                 if (!s)
 441                         return -ENOMEM;
 442
 443                 if (!path_is_normalized(s)) {
 444                         free(s);
 445                         return -EINVAL;
 446                 }
 447         }
 448
 449         if (ret)
 450                 *ret = s;
 451         else
 452                 free(s);
 453
 454         return 0;
 455 }
 456
 457 int unit_name_replace_instance(const char *f, const char *i, char **ret) {
 458         const char *p, *e;
 459         char *s;
 460         size_t a, b;
 461
 462         assert(f);
 463         assert(i);
 464         assert(ret);
 465
 466         if (!unit_name_is_valid(f, UNIT_NAME_INSTANCE|UNIT_NAME_TEMPLATE))
 467                 return -EINVAL;
 468         if (!unit_instance_is_valid(i))
 469                 return -EINVAL;
 470
 471         assert_se(p = strchr(f, '@'));
 472         assert_se(e = strrchr(f, '.'));
 473
 474         a = p - f;
 475         b = strlen(i);
 476
 477         s = new(char, a + 1 + b + strlen(e) + 1);
 478         if (!s)
 479                 return -ENOMEM;
 480
 481         strcpy(mempcpy(mempcpy(s, f, a + 1), i, b), e);
 482
 483         *ret = s;
 484         return 0;
 485 }
 486
 487 int unit_name_template(const char *f, char **ret) {
 488         const char *p, *e;
 489         char *s;
 490         size_t a;
 491
 492         assert(f);
 493         assert(ret);
 494
 495         if (!unit_name_is_valid(f, UNIT_NAME_INSTANCE|UNIT_NAME_TEMPLATE))
 496                 return -EINVAL;
 497
 498         assert_se(p = strchr(f, '@'));
 499         assert_se(e = strrchr(f, '.'));
 500
 501         a = p - f;
 502
 503         s = new(char, a + 1 + strlen(e) + 1);
 504         if (!s)
 505                 return -ENOMEM;
 506
 507         strcpy(mempcpy(s, f, a + 1), e);
 508
 509         *ret = s;
 510         return 0;
 511 }
 512
 513 int unit_name_from_path(const char *path, const char *suffix, char **ret) {
 514         _cleanup_free_ char *p = NULL;
 515         char *s = NULL;
 516         int r;
 517
 518         assert(path);
 519         assert(suffix);
 520         assert(ret);
 521
 522         if (!unit_suffix_is_valid(suffix))
 523                 return -EINVAL;
 524
 525         r = unit_name_path_escape(path, &p);
 526         if (r < 0)
 527                 return r;
 528
 529         s = strappend(p, suffix);
 530         if (!s)
 531                 return -ENOMEM;
 532
 533         *ret = s;
 534         return 0;
 535 }
 536
 537 int unit_name_from_path_instance(const char *prefix, const char *path, const char *suffix, char **ret) {
 538         _cleanup_free_ char *p = NULL;
 539         char *s;
 540         int r;
 541
 542         assert(prefix);
 543         assert(path);
 544         assert(suffix);
 545         assert(ret);
 546
 547         if (!unit_prefix_is_valid(prefix))
 548                 return -EINVAL;
 549
 550         if (!unit_suffix_is_valid(suffix))
 551                 return -EINVAL;
 552
 553         r = unit_name_path_escape(path, &p);
 554         if (r < 0)
 555                 return r;
 556
 557         s = strjoin(prefix, "@", p, suffix);
 558         if (!s)
 559                 return -ENOMEM;
 560
 561         *ret = s;
 562         return 0;
 563 }
 564
 565 int unit_name_to_path(const char *name, char **ret) {
 566         _cleanup_free_ char *prefix = NULL;
 567         int r;
 568
 569         assert(name);
 570
 571         r = unit_name_to_prefix(name, &prefix);
 572         if (r < 0)
 573                 return r;
 574
 575         return unit_name_path_unescape(prefix, ret);
 576 }
 577
 578 static bool do_escape_mangle(const char *f, bool allow_globs, char *t) {
 579         const char *valid_chars;
 580         bool mangled = false;
 581
 582         assert(f);
 583         assert(t);
 584
 585         /* We'll only escape the obvious characters here, to play safe.
 586          *
 587          * Returns true if any characters were mangled, false otherwise.
 588          */
 589
 590         valid_chars = allow_globs ? VALID_CHARS_GLOB : VALID_CHARS_WITH_AT;
 591
 592         for (; *f; f++)
 593                 if (*f == '/') {
 594                         *(t++) = '-';
 595                         mangled = true;
 596                 } else if (!strchr(valid_chars, *f)) {
 597                         t = do_escape_char(*f, t);
 598                         mangled = true;
 599                 } else
 600                         *(t++) = *f;
 601         *t = 0;
 602
 603         return mangled;
 604 }
 605
 606 /**
 607  *  Convert a string to a unit name. /dev/blah is converted to dev-blah.device,
 608  *  /blah/blah is converted to blah-blah.mount, anything else is left alone,
 609  *  except that @suffix is appended if a valid unit suffix is not present.
 610  *
 611  *  If @allow_globs, globs characters are preserved. Otherwise, they are escaped.
 612  */
 613 int unit_name_mangle_with_suffix(const char *name, UnitNameMangle flags, const char *suffix, char **ret) {
 614         char *s;
 615         int r;
 616         bool mangled;
 617
 618         assert(name);
 619         assert(suffix);
 620         assert(ret);
 621
 622         if (isempty(name)) /* We cannot mangle empty unit names to become valid, sorry. */
 623                 return -EINVAL;
 624
 625         if (!unit_suffix_is_valid(suffix))
 626                 return -EINVAL;
 627
 628         /* Already a fully valid unit name? If so, no mangling is necessary... */
 629         if (unit_name_is_valid(name, UNIT_NAME_ANY))
 630                 goto good;
 631
 632         /* Already a fully valid globbing expression? If so, no mangling is necessary either... */
 633         if ((flags & UNIT_NAME_MANGLE_GLOB) &&
 634             string_is_glob(name) &&
 635             in_charset(name, VALID_CHARS_GLOB))
 636                 goto good;
 637
 638         if (is_device_path(name)) {
 639                 r = unit_name_from_path(name, ".device", ret);
 640                 if (r >= 0)
 641                         return 1;
 642                 if (r != -EINVAL)
 643                         return r;
 644         }
 645
 646         if (path_is_absolute(name)) {
 647                 r = unit_name_from_path(name, ".mount", ret);
 648                 if (r >= 0)
 649                         return 1;
 650                 if (r != -EINVAL)
 651                         return r;
 652         }
 653
 654         s = new(char, strlen(name) * 4 + strlen(suffix) + 1);
 655         if (!s)
 656                 return -ENOMEM;
 657
 658         mangled = do_escape_mangle(name, flags & UNIT_NAME_MANGLE_GLOB, s);
 659         if (mangled)
 660                 log_full(flags & UNIT_NAME_MANGLE_WARN ? LOG_NOTICE : LOG_DEBUG,
 661                          "Invalid unit name \"%s\" was escaped as \"%s\" (maybe you should use systemd-escape?)",
 662                          name, s);
 663
 664         /* 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
 665          * valid glob. */
 666         if ((!(flags & UNIT_NAME_MANGLE_GLOB) || !string_is_glob(s)) && unit_name_to_type(s) < 0)
 667                 strcat(s, suffix);
 668
 669         *ret = s;
 670         return 1;
 671
 672 good:
 673         s = strdup(name);
 674         if (!s)
 675                 return -ENOMEM;
 676
 677         *ret = s;
 678         return 0;
 679 }
 680
 681 int slice_build_parent_slice(const char *slice, char **ret) {
 682         char *s, *dash;
 683         int r;
 684
 685         assert(slice);
 686         assert(ret);
 687
 688         if (!slice_name_is_valid(slice))
 689                 return -EINVAL;
 690
 691         if (streq(slice, SPECIAL_ROOT_SLICE)) {
 692                 *ret = NULL;
 693                 return 0;
 694         }
 695
 696         s = strdup(slice);
 697         if (!s)
 698                 return -ENOMEM;
 699
 700         dash = strrchr(s, '-');
 701         if (dash)
 702                 strcpy(dash, ".slice");
 703         else {
 704                 r = free_and_strdup(&s, SPECIAL_ROOT_SLICE);
 705                 if (r < 0) {
 706                         free(s);
 707                         return r;
 708                 }
 709         }
 710
 711         *ret = s;
 712         return 1;
 713 }
 714
 715 int slice_build_subslice(const char *slice, const char*name, char **ret) {
 716         char *subslice;
 717
 718         assert(slice);
 719         assert(name);
 720         assert(ret);
 721
 722         if (!slice_name_is_valid(slice))
 723                 return -EINVAL;
 724
 725         if (!unit_prefix_is_valid(name))
 726                 return -EINVAL;
 727
 728         if (streq(slice, SPECIAL_ROOT_SLICE))
 729                 subslice = strappend(name, ".slice");
 730         else {
 731                 char *e;
 732
 733                 assert_se(e = endswith(slice, ".slice"));
 734
 735                 subslice = new(char, (e - slice) + 1 + strlen(name) + 6 + 1);
 736                 if (!subslice)
 737                         return -ENOMEM;
 738
 739                 stpcpy(stpcpy(stpcpy(mempcpy(subslice, slice, e - slice), "-"), name), ".slice");
 740         }
 741
 742         *ret = subslice;
 743         return 0;
 744 }
 745
 746 bool slice_name_is_valid(const char *name) {
 747         const char *p, *e;
 748         bool dash = false;
 749
 750         if (!unit_name_is_valid(name, UNIT_NAME_PLAIN))
 751                 return false;
 752
 753         if (streq(name, SPECIAL_ROOT_SLICE))
 754                 return true;
 755
 756         e = endswith(name, ".slice");
 757         if (!e)
 758                 return false;
 759
 760         for (p = name; p < e; p++) {
 761
 762                 if (*p == '-') {
 763
 764                         /* Don't allow initial dash */
 765                         if (p == name)
 766                                 return false;
 767
 768                         /* Don't allow multiple dashes */
 769                         if (dash)
 770                                 return false;
 771
 772                         dash = true;
 773                 } else
 774                         dash = false;
 775         }
 776
 777         /* Don't allow trailing hash */
 778         if (dash)
 779                 return false;
 780
 781         return true;
 782 }