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                 char *e;
 386
 387                 if (!path_is_safe(p))
 388                         return -EINVAL;
 389
 390                 /* Truncate trailing slashes */
 391                 e = endswith(p, "/");
 392                 if (e)
 393                         *e = 0;
 394
 395                 /* Truncate leading slashes */
 396                 if (p[0] == '/')
 397                         p++;
 398
 399                 s = unit_name_escape(p);
 400         }
 401         if (!s)
 402                 return -ENOMEM;
 403
 404         *ret = s;
 405         return 0;
 406 }
 407
 408 int unit_name_path_unescape(const char *f, char **ret) {
 409         char *s;
 410         int r;
 411
 412         assert(f);
 413
 414         if (isempty(f))
 415                 return -EINVAL;
 416
 417         if (streq(f, "-")) {
 418                 s = strdup("/");
 419                 if (!s)
 420                         return -ENOMEM;
 421         } else {
 422                 char *w;
 423
 424                 r = unit_name_unescape(f, &w);
 425                 if (r < 0)
 426                         return r;
 427
 428                 /* Don't accept trailing or leading slashes */
 429                 if (startswith(w, "/") || endswith(w, "/")) {
 430                         free(w);
 431                         return -EINVAL;
 432                 }
 433
 434                 /* Prefix a slash again */
 435                 s = strappend("/", w);
 436                 free(w);
 437                 if (!s)
 438                         return -ENOMEM;
 439
 440                 if (!path_is_safe(s)) {
 441                         free(s);
 442                         return -EINVAL;
 443                 }
 444         }
 445
 446         if (ret)
 447                 *ret = s;
 448         else
 449                 free(s);
 450
 451         return 0;
 452 }
 453
 454 int unit_name_replace_instance(const char *f, const char *i, char **ret) {
 455         const char *p, *e;
 456         char *s;
 457         size_t a, b;
 458
 459         assert(f);
 460         assert(i);
 461         assert(ret);
 462
 463         if (!unit_name_is_valid(f, UNIT_NAME_INSTANCE|UNIT_NAME_TEMPLATE))
 464                 return -EINVAL;
 465         if (!unit_instance_is_valid(i))
 466                 return -EINVAL;
 467
 468         assert_se(p = strchr(f, '@'));
 469         assert_se(e = strrchr(f, '.'));
 470
 471         a = p - f;
 472         b = strlen(i);
 473
 474         s = new(char, a + 1 + b + strlen(e) + 1);
 475         if (!s)
 476                 return -ENOMEM;
 477
 478         strcpy(mempcpy(mempcpy(s, f, a + 1), i, b), e);
 479
 480         *ret = s;
 481         return 0;
 482 }
 483
 484 int unit_name_template(const char *f, char **ret) {
 485         const char *p, *e;
 486         char *s;
 487         size_t a;
 488
 489         assert(f);
 490         assert(ret);
 491
 492         if (!unit_name_is_valid(f, UNIT_NAME_INSTANCE|UNIT_NAME_TEMPLATE))
 493                 return -EINVAL;
 494
 495         assert_se(p = strchr(f, '@'));
 496         assert_se(e = strrchr(f, '.'));
 497
 498         a = p - f;
 499
 500         s = new(char, a + 1 + strlen(e) + 1);
 501         if (!s)
 502                 return -ENOMEM;
 503
 504         strcpy(mempcpy(s, f, a + 1), e);
 505
 506         *ret = s;
 507         return 0;
 508 }
 509
 510 int unit_name_from_path(const char *path, const char *suffix, char **ret) {
 511         _cleanup_free_ char *p = NULL;
 512         char *s = NULL;
 513         int r;
 514
 515         assert(path);
 516         assert(suffix);
 517         assert(ret);
 518
 519         if (!unit_suffix_is_valid(suffix))
 520                 return -EINVAL;
 521
 522         r = unit_name_path_escape(path, &p);
 523         if (r < 0)
 524                 return r;
 525
 526         s = strappend(p, suffix);
 527         if (!s)
 528                 return -ENOMEM;
 529
 530         *ret = s;
 531         return 0;
 532 }
 533
 534 int unit_name_from_path_instance(const char *prefix, const char *path, const char *suffix, char **ret) {
 535         _cleanup_free_ char *p = NULL;
 536         char *s;
 537         int r;
 538
 539         assert(prefix);
 540         assert(path);
 541         assert(suffix);
 542         assert(ret);
 543
 544         if (!unit_prefix_is_valid(prefix))
 545                 return -EINVAL;
 546
 547         if (!unit_suffix_is_valid(suffix))
 548                 return -EINVAL;
 549
 550         r = unit_name_path_escape(path, &p);
 551         if (r < 0)
 552                 return r;
 553
 554         s = strjoin(prefix, "@", p, suffix);
 555         if (!s)
 556                 return -ENOMEM;
 557
 558         *ret = s;
 559         return 0;
 560 }
 561
 562 int unit_name_to_path(const char *name, char **ret) {
 563         _cleanup_free_ char *prefix = NULL;
 564         int r;
 565
 566         assert(name);
 567
 568         r = unit_name_to_prefix(name, &prefix);
 569         if (r < 0)
 570                 return r;
 571
 572         return unit_name_path_unescape(prefix, ret);
 573 }
 574
 575 static char *do_escape_mangle(const char *f, UnitNameMangle allow_globs, char *t) {
 576         const char *valid_chars;
 577
 578         assert(f);
 579         assert(IN_SET(allow_globs, UNIT_NAME_GLOB, UNIT_NAME_NOGLOB));
 580         assert(t);
 581
 582         /* We'll only escape the obvious characters here, to play
 583          * safe. */
 584
 585         valid_chars = allow_globs == UNIT_NAME_GLOB ? VALID_CHARS_GLOB : VALID_CHARS_WITH_AT;
 586
 587         for (; *f; f++) {
 588                 if (*f == '/')
 589                         *(t++) = '-';
 590                 else if (!strchr(valid_chars, *f))
 591                         t = do_escape_char(*f, t);
 592                 else
 593                         *(t++) = *f;
 594         }
 595
 596         return t;
 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 allow_globs, const char *suffix, char **ret) {
 607         char *s, *t;
 608         int r;
 609
 610         assert(name);
 611         assert(suffix);
 612         assert(ret);
 613
 614         if (isempty(name)) /* We cannot mangle empty unit names to become valid, sorry. */
 615                 return -EINVAL;
 616
 617         if (!unit_suffix_is_valid(suffix))
 618                 return -EINVAL;
 619
 620         /* Already a fully valid unit name? If so, no mangling is necessary... */
 621         if (unit_name_is_valid(name, UNIT_NAME_ANY))
 622                 goto good;
 623
 624         /* Already a fully valid globbing expression? If so, no mangling is necessary either... */
 625         if (allow_globs == UNIT_NAME_GLOB &&
 626             string_is_glob(name) &&
 627             in_charset(name, VALID_CHARS_GLOB))
 628                 goto good;
 629
 630         if (is_device_path(name)) {
 631                 r = unit_name_from_path(name, ".device", ret);
 632                 if (r >= 0)
 633                         return 1;
 634                 if (r != -EINVAL)
 635                         return r;
 636         }
 637
 638         if (path_is_absolute(name)) {
 639                 r = unit_name_from_path(name, ".mount", ret);
 640                 if (r >= 0)
 641                         return 1;
 642                 if (r != -EINVAL)
 643                         return r;
 644         }
 645
 646         s = new(char, strlen(name) * 4 + strlen(suffix) + 1);
 647         if (!s)
 648                 return -ENOMEM;
 649
 650         t = do_escape_mangle(name, allow_globs, s);
 651         *t = 0;
 652
 653         /* 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
 654          * valid glob. */
 655         if ((allow_globs != UNIT_NAME_GLOB || !string_is_glob(s)) && unit_name_to_type(s) < 0)
 656                 strcpy(t, suffix);
 657
 658         *ret = s;
 659         return 1;
 660
 661 good:
 662         s = strdup(name);
 663         if (!s)
 664                 return -ENOMEM;
 665
 666         *ret = s;
 667         return 0;
 668 }
 669
 670 int slice_build_parent_slice(const char *slice, char **ret) {
 671         char *s, *dash;
 672         int r;
 673
 674         assert(slice);
 675         assert(ret);
 676
 677         if (!slice_name_is_valid(slice))
 678                 return -EINVAL;
 679
 680         if (streq(slice, "-.slice")) {
 681                 *ret = NULL;
 682                 return 0;
 683         }
 684
 685         s = strdup(slice);
 686         if (!s)
 687                 return -ENOMEM;
 688
 689         dash = strrchr(s, '-');
 690         if (dash)
 691                 strcpy(dash, ".slice");
 692         else {
 693                 r = free_and_strdup(&s, "-.slice");
 694                 if (r < 0) {
 695                         free(s);
 696                         return r;
 697                 }
 698         }
 699
 700         *ret = s;
 701         return 1;
 702 }
 703
 704 int slice_build_subslice(const char *slice, const char*name, char **ret) {
 705         char *subslice;
 706
 707         assert(slice);
 708         assert(name);
 709         assert(ret);
 710
 711         if (!slice_name_is_valid(slice))
 712                 return -EINVAL;
 713
 714         if (!unit_prefix_is_valid(name))
 715                 return -EINVAL;
 716
 717         if (streq(slice, "-.slice"))
 718                 subslice = strappend(name, ".slice");
 719         else {
 720                 char *e;
 721
 722                 assert_se(e = endswith(slice, ".slice"));
 723
 724                 subslice = new(char, (e - slice) + 1 + strlen(name) + 6 + 1);
 725                 if (!subslice)
 726                         return -ENOMEM;
 727
 728                 stpcpy(stpcpy(stpcpy(mempcpy(subslice, slice, e - slice), "-"), name), ".slice");
 729         }
 730
 731         *ret = subslice;
 732         return 0;
 733 }
 734
 735 bool slice_name_is_valid(const char *name) {
 736         const char *p, *e;
 737         bool dash = false;
 738
 739         if (!unit_name_is_valid(name, UNIT_NAME_PLAIN))
 740                 return false;
 741
 742         if (streq(name, "-.slice"))
 743                 return true;
 744
 745         e = endswith(name, ".slice");
 746         if (!e)
 747                 return false;
 748
 749         for (p = name; p < e; p++) {
 750
 751                 if (*p == '-') {
 752
 753                         /* Don't allow initial dash */
 754                         if (p == name)
 755                                 return false;
 756
 757                         /* Don't allow multiple dashes */
 758                         if (dash)
 759                                 return false;
 760
 761                         dash = true;
 762                 } else
 763                         dash = false;
 764         }
 765
 766         /* Don't allow trailing hash */
 767         if (dash)
 768                 return false;
 769
 770         return true;
 771 }