src/basic/env-util.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include <errno.h>
   4 #include <limits.h>
   5 #include <stdarg.h>
   6 #include <stdlib.h>
   7 #include <unistd.h>
   8
   9 #include "alloc-util.h"
  10 #include "env-util.h"
  11 #include "errno-util.h"
  12 #include "escape.h"
  13 #include "extract-word.h"
  14 #include "macro.h"
  15 #include "parse-util.h"
  16 #include "path-util.h"
  17 #include "process-util.h"
  18 #include "stdio-util.h"
  19 #include "string-util.h"
  20 #include "strv.h"
  21 #include "utf8.h"
  22
  23 /* We follow bash for the character set. Different shells have different rules. */
  24 #define VALID_BASH_ENV_NAME_CHARS               \
  25         DIGITS LETTERS                          \
  26         "_"
  27
  28 static bool env_name_is_valid_n(const char *e, size_t n) {
  29
  30         if (n == SIZE_MAX)
  31                 n = strlen_ptr(e);
  32
  33         if (n <= 0)
  34                 return false;
  35
  36         assert(e);
  37
  38         if (ascii_isdigit(e[0]))
  39                 return false;
  40
  41         /* POSIX says the overall size of the environment block cannot be > ARG_MAX, an individual assignment
  42          * hence cannot be either. Discounting the equal sign and trailing NUL this hence leaves ARG_MAX-2 as
  43          * longest possible variable name. */
  44         if (n > (size_t) sysconf(_SC_ARG_MAX) - 2)
  45                 return false;
  46
  47         for (const char *p = e; p < e + n; p++)
  48                 if (!strchr(VALID_BASH_ENV_NAME_CHARS, *p))
  49                         return false;
  50
  51         return true;
  52 }
  53
  54 bool env_name_is_valid(const char *e) {
  55         return env_name_is_valid_n(e, strlen_ptr(e));
  56 }
  57
  58 bool env_value_is_valid(const char *e) {
  59         if (!e)
  60                 return false;
  61
  62         if (!utf8_is_valid(e))
  63                 return false;
  64
  65         /* Note that variable *values* may contain control characters, in particular NL, TAB, BS, DEL, ESC…
  66          * When printing those variables with show-environment, we'll escape them. Make sure to print
  67          * environment variables carefully! */
  68
  69         /* POSIX says the overall size of the environment block cannot be > ARG_MAX, an individual assignment
  70          * hence cannot be either. Discounting the shortest possible variable name of length 1, the equal
  71          * sign and trailing NUL this hence leaves ARG_MAX-3 as longest possible variable value. */
  72         if (strlen(e) > sc_arg_max() - 3)
  73                 return false;
  74
  75         return true;
  76 }
  77
  78 bool env_assignment_is_valid(const char *e) {
  79         const char *eq;
  80
  81         eq = strchr(e, '=');
  82         if (!eq)
  83                 return false;
  84
  85         if (!env_name_is_valid_n(e, eq - e))
  86                 return false;
  87
  88         if (!env_value_is_valid(eq + 1))
  89                 return false;
  90
  91         /* POSIX says the overall size of the environment block cannot be > ARG_MAX, hence the individual
  92          * variable assignments cannot be either, but let's leave room for one trailing NUL byte. */
  93         if (strlen(e) > sc_arg_max() - 1)
  94                 return false;
  95
  96         return true;
  97 }
  98
  99 bool strv_env_is_valid(char **e) {
 100         STRV_FOREACH(p, e) {
 101                 size_t k;
 102
 103                 if (!env_assignment_is_valid(*p))
 104                         return false;
 105
 106                 /* Check if there are duplicate assignments */
 107                 k = strcspn(*p, "=");
 108                 STRV_FOREACH(q, p + 1)
 109                         if (strneq(*p, *q, k) && (*q)[k] == '=')
 110                                 return false;
 111         }
 112
 113         return true;
 114 }
 115
 116 bool strv_env_name_is_valid(char **l) {
 117         STRV_FOREACH(p, l) {
 118                 if (!env_name_is_valid(*p))
 119                         return false;
 120
 121                 if (strv_contains(p + 1, *p))
 122                         return false;
 123         }
 124
 125         return true;
 126 }
 127
 128 bool strv_env_name_or_assignment_is_valid(char **l) {
 129         STRV_FOREACH(p, l) {
 130                 if (!env_assignment_is_valid(*p) && !env_name_is_valid(*p))
 131                         return false;
 132
 133                 if (strv_contains(p + 1, *p))
 134                         return false;
 135         }
 136
 137         return true;
 138 }
 139
 140 static int env_append(char **e, char ***k, char **a) {
 141         assert(e);
 142         assert(k);
 143         assert(*k >= e);
 144
 145         if (!a)
 146                 return 0;
 147
 148         /* Expects the following arguments: 'e' shall point to the beginning of an strv we are going to append to, 'k'
 149          * to a pointer pointing to the NULL entry at the end of the same array. 'a' shall point to another strv.
 150          *
 151          * This call adds every entry of 'a' to 'e', either overriding an existing matching entry, or appending to it.
 152          *
 153          * This call assumes 'e' has enough pre-allocated space to grow by all of 'a''s items. */
 154
 155         for (; *a; a++) {
 156                 char **j, *c;
 157                 size_t n;
 158
 159                 n = strcspn(*a, "=");
 160                 if ((*a)[n] == '=')
 161                         n++;
 162
 163                 for (j = e; j < *k; j++)
 164                         if (strneq(*j, *a, n))
 165                                 break;
 166
 167                 c = strdup(*a);
 168                 if (!c)
 169                         return -ENOMEM;
 170
 171                 if (j >= *k) { /* Append to the end? */
 172                         (*k)[0] = c;
 173                         (*k)[1] = NULL;
 174                         (*k)++;
 175                 } else
 176                         free_and_replace(*j, c); /* Override existing item */
 177         }
 178
 179         return 0;
 180 }
 181
 182 char** _strv_env_merge(char **first, ...) {
 183         _cleanup_strv_free_ char **merged = NULL;
 184         char **k;
 185         va_list ap;
 186
 187         /* Merges an arbitrary number of environment sets */
 188
 189         size_t n = strv_length(first);
 190
 191         va_start(ap, first);
 192         for (;;) {
 193                 char **l;
 194
 195                 l = va_arg(ap, char**);
 196                 if (l == POINTER_MAX)
 197                         break;
 198
 199                 n += strv_length(l);
 200         }
 201         va_end(ap);
 202
 203         k = merged = new(char*, n + 1);
 204         if (!merged)
 205                 return NULL;
 206         merged[0] = NULL;
 207
 208         if (env_append(merged, &k, first) < 0)
 209                 return NULL;
 210
 211         va_start(ap, first);
 212         for (;;) {
 213                 char **l;
 214
 215                 l = va_arg(ap, char**);
 216                 if (l == POINTER_MAX)
 217                         break;
 218
 219                 if (env_append(merged, &k, l) < 0) {
 220                         va_end(ap);
 221                         return NULL;
 222                 }
 223         }
 224         va_end(ap);
 225
 226         return TAKE_PTR(merged);
 227 }
 228
 229 static bool env_match(const char *t, const char *pattern) {
 230         assert(t);
 231         assert(pattern);
 232
 233         /* pattern a matches string a
 234          *         a matches a=
 235          *         a matches a=b
 236          *         a= matches a=
 237          *         a=b matches a=b
 238          *         a= does not match a
 239          *         a=b does not match a=
 240          *         a=b does not match a
 241          *         a=b does not match a=c */
 242
 243         if (streq(t, pattern))
 244                 return true;
 245
 246         if (!strchr(pattern, '=')) {
 247                 size_t l = strlen(pattern);
 248
 249                 return strneq(t, pattern, l) && t[l] == '=';
 250         }
 251
 252         return false;
 253 }
 254
 255 static bool env_entry_has_name(const char *entry, const char *name) {
 256         const char *t;
 257
 258         assert(entry);
 259         assert(name);
 260
 261         t = startswith(entry, name);
 262         if (!t)
 263                 return false;
 264
 265         return *t == '=';
 266 }
 267
 268 char **strv_env_delete(char **x, size_t n_lists, ...) {
 269         size_t n, i = 0;
 270         _cleanup_strv_free_ char **t = NULL;
 271         va_list ap;
 272
 273         /* Deletes every entry from x that is mentioned in the other
 274          * string lists */
 275
 276         n = strv_length(x);
 277
 278         t = new(char*, n+1);
 279         if (!t)
 280                 return NULL;
 281
 282         STRV_FOREACH(k, x) {
 283                 va_start(ap, n_lists);
 284                 for (size_t v = 0; v < n_lists; v++) {
 285                         char **l;
 286
 287                         l = va_arg(ap, char**);
 288                         STRV_FOREACH(j, l)
 289                                 if (env_match(*k, *j))
 290                                         goto skip;
 291                 }
 292                 va_end(ap);
 293
 294                 t[i] = strdup(*k);
 295                 if (!t[i])
 296                         return NULL;
 297
 298                 i++;
 299                 continue;
 300
 301         skip:
 302                 va_end(ap);
 303         }
 304
 305         t[i] = NULL;
 306
 307         assert(i <= n);
 308
 309         return TAKE_PTR(t);
 310 }
 311
 312 char **strv_env_unset(char **l, const char *p) {
 313         char **f, **t;
 314
 315         if (!l)
 316                 return NULL;
 317
 318         assert(p);
 319
 320         /* Drops every occurrence of the env var setting p in the
 321          * string list. Edits in-place. */
 322
 323         for (f = t = l; *f; f++) {
 324
 325                 if (env_match(*f, p)) {
 326                         free(*f);
 327                         continue;
 328                 }
 329
 330                 *(t++) = *f;
 331         }
 332
 333         *t = NULL;
 334         return l;
 335 }
 336
 337 char **strv_env_unset_many(char **l, ...) {
 338         char **f, **t;
 339
 340         if (!l)
 341                 return NULL;
 342
 343         /* Like strv_env_unset() but applies many at once. Edits in-place. */
 344
 345         for (f = t = l; *f; f++) {
 346                 bool found = false;
 347                 const char *p;
 348                 va_list ap;
 349
 350                 va_start(ap, l);
 351
 352                 while ((p = va_arg(ap, const char*))) {
 353                         if (env_match(*f, p)) {
 354                                 found = true;
 355                                 break;
 356                         }
 357                 }
 358
 359                 va_end(ap);
 360
 361                 if (found) {
 362                         free(*f);
 363                         continue;
 364                 }
 365
 366                 *(t++) = *f;
 367         }
 368
 369         *t = NULL;
 370         return l;
 371 }
 372
 373 int strv_env_replace_consume(char ***l, char *p) {
 374         const char *t, *name;
 375         int r;
 376
 377         assert(p);
 378
 379         /* Replace first occurrence of the env var or add a new one in the string list. Drop other
 380          * occurrences. Edits in-place. Does not copy p and CONSUMES p EVEN ON FAILURE.
 381          *
 382          * p must be a valid key=value assignment. */
 383
 384         t = strchr(p, '=');
 385         if (!t) {
 386                 free(p);
 387                 return -EINVAL;
 388         }
 389
 390         name = strndupa_safe(p, t - p);
 391
 392         STRV_FOREACH(f, *l)
 393                 if (env_entry_has_name(*f, name)) {
 394                         free_and_replace(*f, p);
 395                         strv_env_unset(f + 1, *f);
 396                         return 0;
 397                 }
 398
 399         /* We didn't find a match, we need to append p or create a new strv */
 400         r = strv_consume(l, p);
 401         if (r < 0)
 402                 return r;
 403
 404         return 1;
 405 }
 406
 407 int strv_env_replace_strdup(char ***l, const char *assignment) {
 408         /* Like strv_env_replace_consume(), but copies the argument. */
 409
 410         char *p = strdup(assignment);
 411         if (!p)
 412                 return -ENOMEM;
 413
 414         return strv_env_replace_consume(l, p);
 415 }
 416
 417 int strv_env_replace_strdup_passthrough(char ***l, const char *assignment) {
 418         /* Like strv_env_replace_strdup(), but pulls the variable from the environment of
 419          * the calling program, if a variable name without value is specified.
 420          */
 421         char *p;
 422
 423         if (strchr(assignment, '=')) {
 424                 if (!env_assignment_is_valid(assignment))
 425                         return -EINVAL;
 426
 427                 p = strdup(assignment);
 428         } else {
 429                 if (!env_name_is_valid(assignment))
 430                         return -EINVAL;
 431
 432                 /* If we can't find the variable in our environment, we will use
 433                  * the empty string. This way "passthrough" is equivalent to passing
 434                  * --setenv=FOO=$FOO in the shell. */
 435                 p = strjoin(assignment, "=", secure_getenv(assignment));
 436         }
 437         if (!p)
 438                 return -ENOMEM;
 439
 440         return strv_env_replace_consume(l, p);
 441 }
 442
 443 int strv_env_assign(char ***l, const char *key, const char *value) {
 444         if (!env_name_is_valid(key))
 445                 return -EINVAL;
 446
 447         /* NULL removes assignment, "" creates an empty assignment. */
 448
 449         if (!value) {
 450                 strv_env_unset(*l, key);
 451                 return 0;
 452         }
 453
 454         char *p = strjoin(key, "=", value);
 455         if (!p)
 456                 return -ENOMEM;
 457
 458         return strv_env_replace_consume(l, p);
 459 }
 460
 461 int _strv_env_assign_many(char ***l, ...) {
 462         va_list ap;
 463         int r;
 464
 465         assert(l);
 466
 467         va_start(ap, l);
 468         for (;;) {
 469                 const char *key, *value;
 470
 471                 key = va_arg(ap, const char *);
 472                 if (!key)
 473                         break;
 474
 475                 if (!env_name_is_valid(key)) {
 476                         va_end(ap);
 477                         return -EINVAL;
 478                 }
 479
 480                 value = va_arg(ap, const char *);
 481                 if (!value) {
 482                         strv_env_unset(*l, key);
 483                         continue;
 484                 }
 485
 486                 char *p = strjoin(key, "=", value);
 487                 if (!p) {
 488                         va_end(ap);
 489                         return -ENOMEM;
 490                 }
 491
 492                 r = strv_env_replace_consume(l, p);
 493                 if (r < 0) {
 494                         va_end(ap);
 495                         return r;
 496                 }
 497         }
 498         va_end(ap);
 499
 500         return 0;
 501 }
 502
 503 char *strv_env_get_n(char **l, const char *name, size_t k, ReplaceEnvFlags flags) {
 504         assert(name);
 505
 506         if (k == SIZE_MAX)
 507                 k = strlen_ptr(name);
 508         if (k <= 0)
 509                 return NULL;
 510
 511         STRV_FOREACH_BACKWARDS(i, l)
 512                 if (strneq(*i, name, k) &&
 513                     (*i)[k] == '=')
 514                         return *i + k + 1;
 515
 516         if (flags & REPLACE_ENV_USE_ENVIRONMENT) {
 517                 const char *t;
 518
 519                 /* Safety check that the name is not overly long, before we do a stack allocation */
 520                 if (k > (size_t) sysconf(_SC_ARG_MAX) - 2)
 521                         return NULL;
 522
 523                 t = strndupa_safe(name, k);
 524                 return getenv(t);
 525         };
 526
 527         return NULL;
 528 }
 529
 530 char *strv_env_pairs_get(char **l, const char *name) {
 531         char *result = NULL;
 532
 533         assert(name);
 534
 535         STRV_FOREACH_PAIR(key, value, l)
 536                 if (streq(*key, name))
 537                         result = *value;
 538
 539         return result;
 540 }
 541
 542 char **strv_env_clean_with_callback(char **e, void (*invalid_callback)(const char *p, void *userdata), void *userdata) {
 543         int k = 0;
 544
 545         STRV_FOREACH(p, e) {
 546                 size_t n;
 547                 bool duplicate = false;
 548
 549                 if (!env_assignment_is_valid(*p)) {
 550                         if (invalid_callback)
 551                                 invalid_callback(*p, userdata);
 552                         free(*p);
 553                         continue;
 554                 }
 555
 556                 n = strcspn(*p, "=");
 557                 STRV_FOREACH(q, p + 1)
 558                         if (strneq(*p, *q, n) && (*q)[n] == '=') {
 559                                 duplicate = true;
 560                                 break;
 561                         }
 562
 563                 if (duplicate) {
 564                         free(*p);
 565                         continue;
 566                 }
 567
 568                 e[k++] = *p;
 569         }
 570
 571         if (e)
 572                 e[k] = NULL;
 573
 574         return e;
 575 }
 576
 577 static int strv_extend_with_length(char ***l, const char *s, size_t n) {
 578         char *c;
 579
 580         c = strndup(s, n);
 581         if (!c)
 582                 return -ENOMEM;
 583
 584         return strv_consume(l, c);
 585 }
 586
 587 static int strv_env_get_n_validated(
 588                 char **env,
 589                 const char *name,
 590                 size_t l,
 591                 ReplaceEnvFlags flags,
 592                 char **ret,              /* points into the env block! do not free! */
 593                 char ***unset_variables, /* updated in place */
 594                 char ***bad_variables) { /* ditto */
 595
 596         char *e;
 597         int r;
 598
 599         assert(l == 0 || name);
 600         assert(ret);
 601
 602         if (env_name_is_valid_n(name, l)) {
 603                 e = strv_env_get_n(env, name, l, flags);
 604                 if (!e && unset_variables) {
 605                         r = strv_extend_with_length(unset_variables, name, l);
 606                         if (r < 0)
 607                                 return r;
 608                 }
 609         } else {
 610                 e = NULL; /* Resolve invalid variable names the same way as unset ones */
 611
 612                 if (bad_variables) {
 613                         r = strv_extend_with_length(bad_variables, name, l);
 614                         if (r < 0)
 615                                 return r;
 616                 }
 617         }
 618
 619         *ret = e;
 620         return !!e;
 621 }
 622
 623 int replace_env_full(
 624                 const char *format,
 625                 size_t n,
 626                 char **env,
 627                 ReplaceEnvFlags flags,
 628                 char **ret,
 629                 char ***ret_unset_variables,
 630                 char ***ret_bad_variables) {
 631
 632         enum {
 633                 WORD,
 634                 CURLY,
 635                 VARIABLE,
 636                 VARIABLE_RAW,
 637                 TEST,
 638                 DEFAULT_VALUE,
 639                 ALTERNATE_VALUE,
 640         } state = WORD;
 641
 642         _cleanup_strv_free_ char **unset_variables = NULL, **bad_variables = NULL;
 643         const char *e, *word = format, *test_value = NULL; /* test_value is initialized to appease gcc */
 644         _cleanup_free_ char *s = NULL;
 645         char ***pu, ***pb, *k;
 646         size_t i, len = 0; /* len is initialized to appease gcc */
 647         int nest = 0, r;
 648
 649         assert(format);
 650
 651         if (n == SIZE_MAX)
 652                 n = strlen(format);
 653
 654         pu = ret_unset_variables ? &unset_variables : NULL;
 655         pb = ret_bad_variables ? &bad_variables : NULL;
 656
 657         for (e = format, i = 0; *e && i < n; e ++, i ++)
 658                 switch (state) {
 659
 660                 case WORD:
 661                         if (*e == '$')
 662                                 state = CURLY;
 663                         break;
 664
 665                 case CURLY:
 666                         if (*e == '{') {
 667                                 k = strnappend(s, word, e-word-1);
 668                                 if (!k)
 669                                         return -ENOMEM;
 670
 671                                 free_and_replace(s, k);
 672
 673                                 word = e-1;
 674                                 state = VARIABLE;
 675                                 nest++;
 676
 677                         } else if (*e == '$') {
 678                                 k = strnappend(s, word, e-word);
 679                                 if (!k)
 680                                         return -ENOMEM;
 681
 682                                 free_and_replace(s, k);
 683
 684                                 word = e+1;
 685                                 state = WORD;
 686
 687                         } else if (FLAGS_SET(flags, REPLACE_ENV_ALLOW_BRACELESS) && strchr(VALID_BASH_ENV_NAME_CHARS, *e)) {
 688                                 k = strnappend(s, word, e-word-1);
 689                                 if (!k)
 690                                         return -ENOMEM;
 691
 692                                 free_and_replace(s, k);
 693
 694                                 word = e-1;
 695                                 state = VARIABLE_RAW;
 696
 697                         } else
 698                                 state = WORD;
 699                         break;
 700
 701                 case VARIABLE:
 702                         if (*e == '}') {
 703                                 char *t;
 704
 705                                 r = strv_env_get_n_validated(env, word+2, e-word-2, flags, &t, pu, pb);
 706                                 if (r < 0)
 707                                         return r;
 708
 709                                 if (!strextend(&s, t))
 710                                         return -ENOMEM;
 711
 712                                 word = e+1;
 713                                 state = WORD;
 714                                 nest--;
 715                         } else if (*e == ':') {
 716                                 if (flags & REPLACE_ENV_ALLOW_EXTENDED) {
 717                                         len = e - word - 2;
 718                                         state = TEST;
 719                                 } else
 720                                         /* Treat this as unsupported syntax, i.e. do no replacement */
 721                                         state = WORD;
 722                         }
 723                         break;
 724
 725                 case TEST:
 726                         if (*e == '-')
 727                                 state = DEFAULT_VALUE;
 728                         else if (*e == '+')
 729                                 state = ALTERNATE_VALUE;
 730                         else {
 731                                 state = WORD;
 732                                 break;
 733                         }
 734
 735                         test_value = e+1;
 736                         break;
 737
 738                 case DEFAULT_VALUE: /* fall through */
 739                 case ALTERNATE_VALUE:
 740                         assert(flags & REPLACE_ENV_ALLOW_EXTENDED);
 741
 742                         if (*e == '{') {
 743                                 nest++;
 744                                 break;
 745                         }
 746
 747                         if (*e != '}')
 748                                 break;
 749
 750                         nest--;
 751                         if (nest == 0) {
 752                                 _cleanup_strv_free_ char **u = NULL, **b = NULL;
 753                                 _cleanup_free_ char *v = NULL;
 754                                 char *t = NULL;
 755
 756                                 r = strv_env_get_n_validated(env, word+2, len, flags, &t, pu, pb);
 757                                 if (r < 0)
 758                                         return r;
 759
 760                                 if (t && state == ALTERNATE_VALUE) {
 761                                         r = replace_env_full(test_value, e-test_value, env, flags, &v, pu ? &u : NULL, pb ? &b : NULL);
 762                                         if (r < 0)
 763                                                 return r;
 764
 765                                         t = v;
 766                                 } else if (!t && state == DEFAULT_VALUE) {
 767                                         r = replace_env_full(test_value, e-test_value, env, flags, &v, pu ? &u : NULL, pb ? &b : NULL);
 768                                         if (r < 0)
 769                                                 return r;
 770
 771                                         t = v;
 772                                 }
 773
 774                                 r = strv_extend_strv(&unset_variables, u, /* filter_duplicates= */ true);
 775                                 if (r < 0)
 776                                         return r;
 777                                 r = strv_extend_strv(&bad_variables, b, /* filter_duplicates= */ true);
 778                                 if (r < 0)
 779                                         return r;
 780
 781                                 if (!strextend(&s, t))
 782                                         return -ENOMEM;
 783
 784                                 word = e+1;
 785                                 state = WORD;
 786                         }
 787                         break;
 788
 789                 case VARIABLE_RAW:
 790                         assert(flags & REPLACE_ENV_ALLOW_BRACELESS);
 791
 792                         if (!strchr(VALID_BASH_ENV_NAME_CHARS, *e)) {
 793                                 char *t = NULL;
 794
 795                                 r = strv_env_get_n_validated(env, word+1, e-word-1, flags, &t, &unset_variables, &bad_variables);
 796                                 if (r < 0)
 797                                         return r;
 798
 799                                 if (!strextend(&s, t))
 800                                         return -ENOMEM;
 801
 802                                 word = e--;
 803                                 i--;
 804                                 state = WORD;
 805                         }
 806                         break;
 807                 }
 808
 809         if (state == VARIABLE_RAW) {
 810                 char *t;
 811
 812                 assert(flags & REPLACE_ENV_ALLOW_BRACELESS);
 813
 814                 r = strv_env_get_n_validated(env, word+1, e-word-1, flags, &t, &unset_variables, &bad_variables);
 815                 if (r < 0)
 816                         return r;
 817
 818                 if (!strextend(&s, t))
 819                         return -ENOMEM;
 820
 821         } else if (!strextendn(&s, word, e-word))
 822                 return -ENOMEM;
 823
 824         if (ret_unset_variables)
 825                 *ret_unset_variables = TAKE_PTR(unset_variables);
 826         if (ret_bad_variables)
 827                 *ret_bad_variables = TAKE_PTR(bad_variables);
 828
 829         if (ret)
 830                 *ret = TAKE_PTR(s);
 831
 832         return 0;
 833 }
 834
 835 int replace_env_argv(
 836                 char **argv,
 837                 char **env,
 838                 char ***ret,
 839                 char ***ret_unset_variables,
 840                 char ***ret_bad_variables) {
 841
 842         _cleanup_strv_free_ char **n = NULL, **unset_variables = NULL, **bad_variables = NULL;
 843         size_t k = 0, l = 0;
 844         int r;
 845
 846         l = strv_length(argv);
 847
 848         n = new(char*, l+1);
 849         if (!n)
 850                 return -ENOMEM;
 851
 852         STRV_FOREACH(i, argv) {
 853                 const char *word = *i;
 854
 855                 /* If $FOO appears as single word, replace it by the split up variable */
 856                 if (word[0] == '$' && !IN_SET(word[1], '{', '$')) {
 857                         _cleanup_strv_free_ char **m = NULL;
 858                         const char *name = word + 1;
 859                         char *e, **w;
 860                         size_t q;
 861
 862                         if (env_name_is_valid(name)) {
 863                                 e = strv_env_get(env, name);
 864                                 if (e)
 865                                         r = strv_split_full(&m, e, WHITESPACE, EXTRACT_RELAX|EXTRACT_UNQUOTE);
 866                                 else if (ret_unset_variables)
 867                                         r = strv_extend(&unset_variables, name);
 868                                 else
 869                                         r = 0;
 870                         } else if (ret_bad_variables)
 871                                 r = strv_extend(&bad_variables, name);
 872                         else
 873                                 r = 0;
 874                         if (r < 0)
 875                                 return r;
 876
 877                         q = strv_length(m);
 878                         l = l + q - 1;
 879
 880                         w = reallocarray(n, l + 1, sizeof(char*));
 881                         if (!w)
 882                                 return -ENOMEM;
 883
 884                         n = w;
 885                         if (m) {
 886                                 memcpy(n + k, m, (q + 1) * sizeof(char*));
 887                                 m = mfree(m);
 888                         }
 889
 890                         k += q;
 891                         continue;
 892                 }
 893
 894                 _cleanup_strv_free_ char **u = NULL, **b = NULL;
 895
 896                 /* If ${FOO} appears as part of a word, replace it by the variable as-is */
 897                 r = replace_env_full(
 898                                 word,
 899                                 /* length= */ SIZE_MAX,
 900                                 env,
 901                                 /* flags= */ 0,
 902                                 n + k,
 903                                 ret_unset_variables ? &u : NULL,
 904                                 ret_bad_variables ? &b : NULL);
 905                 if (r < 0)
 906                         return r;
 907                 n[++k] = NULL;
 908
 909                 r = strv_extend_strv(&unset_variables, u, /* filter_duplicates= */ true);
 910                 if (r < 0)
 911                         return r;
 912
 913                 r = strv_extend_strv(&bad_variables, b, /*filter_duplicates= */ true);
 914                 if (r < 0)
 915                         return r;
 916         }
 917
 918         if (ret_unset_variables) {
 919                 strv_uniq(strv_sort(unset_variables));
 920                 *ret_unset_variables = TAKE_PTR(unset_variables);
 921         }
 922         if (ret_bad_variables) {
 923                 strv_uniq(strv_sort(bad_variables));
 924                 *ret_bad_variables = TAKE_PTR(bad_variables);
 925         }
 926
 927         *ret = TAKE_PTR(n);
 928         return 0;
 929 }
 930
 931 int getenv_bool(const char *p) {
 932         const char *e;
 933
 934         e = getenv(p);
 935         if (!e)
 936                 return -ENXIO;
 937
 938         return parse_boolean(e);
 939 }
 940
 941 int getenv_bool_secure(const char *p) {
 942         const char *e;
 943
 944         e = secure_getenv(p);
 945         if (!e)
 946                 return -ENXIO;
 947
 948         return parse_boolean(e);
 949 }
 950
 951 int getenv_uint64_secure(const char *p, uint64_t *ret) {
 952         const char *e;
 953
 954         assert(p);
 955
 956         e = secure_getenv(p);
 957         if (!e)
 958                 return -ENXIO;
 959
 960         return safe_atou64(e, ret);
 961 }
 962
 963 int set_unset_env(const char *name, const char *value, bool overwrite) {
 964         assert(name);
 965
 966         if (value)
 967                 return RET_NERRNO(setenv(name, value, overwrite));
 968
 969         return RET_NERRNO(unsetenv(name));
 970 }
 971
 972 int putenv_dup(const char *assignment, bool override) {
 973         const char *e, *n;
 974
 975         e = strchr(assignment, '=');
 976         if (!e)
 977                 return -EINVAL;
 978
 979         n = strndupa_safe(assignment, e - assignment);
 980
 981         /* This is like putenv(), but uses setenv() so that our memory doesn't become part of environ[]. */
 982         return RET_NERRNO(setenv(n, e + 1, override));
 983 }
 984
 985 int setenv_systemd_exec_pid(bool update_only) {
 986         char str[DECIMAL_STR_MAX(pid_t)];
 987         const char *e;
 988
 989         /* Update $SYSTEMD_EXEC_PID=pid except when '*' is set for the variable. */
 990
 991         e = secure_getenv("SYSTEMD_EXEC_PID");
 992         if (!e && update_only)
 993                 return 0;
 994
 995         if (streq_ptr(e, "*"))
 996                 return 0;
 997
 998         xsprintf(str, PID_FMT, getpid_cached());
 999
1000         if (setenv("SYSTEMD_EXEC_PID", str, 1) < 0)
1001                 return -errno;
1002
1003         return 1;
1004 }
1005
1006 int getenv_path_list(const char *name, char ***ret_paths) {
1007         _cleanup_strv_free_ char **l = NULL;
1008         const char *e;
1009         int r;
1010
1011         assert(name);
1012         assert(ret_paths);
1013
1014         e = secure_getenv(name);
1015         if (!e)
1016                 return -ENXIO;
1017
1018         r = strv_split_full(&l, e, ":", EXTRACT_DONT_COALESCE_SEPARATORS);
1019         if (r < 0)
1020                 return log_debug_errno(r, "Failed to parse $%s: %m", name);
1021
1022         STRV_FOREACH(p, l) {
1023                 if (!path_is_absolute(*p))
1024                         return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
1025                                                "Path '%s' is not absolute, refusing.", *p);
1026
1027                 if (!path_is_normalized(*p))
1028                         return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
1029                                                "Path '%s' is not normalized, refusing.", *p);
1030
1031                 if (path_equal(*p, "/"))
1032                         return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
1033                                                "Path '%s' is the root fs, refusing.", *p);
1034         }
1035
1036         if (strv_isempty(l))
1037                 return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
1038                                        "No paths specified, refusing.");
1039
1040         *ret_paths = TAKE_PTR(l);
1041         return 1;
1042 }
1043
1044 int getenv_steal_erase(const char *name, char **ret) {
1045         _cleanup_(erase_and_freep) char *a = NULL;
1046         char *e;
1047
1048         assert(name);
1049
1050         /* Reads an environment variable, makes a copy of it, erases its memory in the environment block and removes
1051          * it from there. Usecase: reading passwords from the env block (which is a bad idea, but useful for
1052          * testing, and given that people are likely going to misuse this, be thorough) */
1053
1054         e = getenv(name);
1055         if (!e) {
1056                 if (ret)
1057                         *ret = NULL;
1058                 return 0;
1059         }
1060
1061         if (ret) {
1062                 a = strdup(e);
1063                 if (!a)
1064                         return -ENOMEM;
1065         }
1066
1067         string_erase(e);
1068
1069         if (unsetenv(name) < 0)
1070                 return -errno;
1071
1072         if (ret)
1073                 *ret = TAKE_PTR(a);
1074
1075         return 1;
1076 }