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_assignf(char ***l, const char *key, const char *valuef, ...) {
 462         int r;
 463
 464         assert(l);
 465         assert(key);
 466
 467         if (!env_name_is_valid(key))
 468                 return -EINVAL;
 469
 470         if (!valuef) {
 471                 strv_env_unset(*l, key);
 472                 return 0;
 473         }
 474
 475         _cleanup_free_ char *value = NULL;
 476         va_list ap;
 477         va_start(ap, valuef);
 478         r = vasprintf(&value, valuef, ap);
 479         va_end(ap);
 480         if (r < 0)
 481                 return -ENOMEM;
 482
 483         char *p = strjoin(key, "=", value);
 484         if (!p)
 485                 return -ENOMEM;
 486
 487         return strv_env_replace_consume(l, p);
 488 }
 489
 490 int _strv_env_assign_many(char ***l, ...) {
 491         va_list ap;
 492         int r;
 493
 494         assert(l);
 495
 496         va_start(ap, l);
 497         for (;;) {
 498                 const char *key, *value;
 499
 500                 key = va_arg(ap, const char *);
 501                 if (!key)
 502                         break;
 503
 504                 if (!env_name_is_valid(key)) {
 505                         va_end(ap);
 506                         return -EINVAL;
 507                 }
 508
 509                 value = va_arg(ap, const char *);
 510                 if (!value) {
 511                         strv_env_unset(*l, key);
 512                         continue;
 513                 }
 514
 515                 char *p = strjoin(key, "=", value);
 516                 if (!p) {
 517                         va_end(ap);
 518                         return -ENOMEM;
 519                 }
 520
 521                 r = strv_env_replace_consume(l, p);
 522                 if (r < 0) {
 523                         va_end(ap);
 524                         return r;
 525                 }
 526         }
 527         va_end(ap);
 528
 529         return 0;
 530 }
 531
 532 char *strv_env_get_n(char **l, const char *name, size_t k, ReplaceEnvFlags flags) {
 533         assert(name);
 534
 535         if (k == SIZE_MAX)
 536                 k = strlen_ptr(name);
 537         if (k <= 0)
 538                 return NULL;
 539
 540         STRV_FOREACH_BACKWARDS(i, l)
 541                 if (strneq(*i, name, k) &&
 542                     (*i)[k] == '=')
 543                         return *i + k + 1;
 544
 545         if (flags & REPLACE_ENV_USE_ENVIRONMENT) {
 546                 const char *t;
 547
 548                 /* Safety check that the name is not overly long, before we do a stack allocation */
 549                 if (k > (size_t) sysconf(_SC_ARG_MAX) - 2)
 550                         return NULL;
 551
 552                 t = strndupa_safe(name, k);
 553                 return getenv(t);
 554         };
 555
 556         return NULL;
 557 }
 558
 559 char *strv_env_pairs_get(char **l, const char *name) {
 560         char *result = NULL;
 561
 562         assert(name);
 563
 564         STRV_FOREACH_PAIR(key, value, l)
 565                 if (streq(*key, name))
 566                         result = *value;
 567
 568         return result;
 569 }
 570
 571 char **strv_env_clean_with_callback(char **e, void (*invalid_callback)(const char *p, void *userdata), void *userdata) {
 572         int k = 0;
 573
 574         STRV_FOREACH(p, e) {
 575                 size_t n;
 576                 bool duplicate = false;
 577
 578                 if (!env_assignment_is_valid(*p)) {
 579                         if (invalid_callback)
 580                                 invalid_callback(*p, userdata);
 581                         free(*p);
 582                         continue;
 583                 }
 584
 585                 n = strcspn(*p, "=");
 586                 STRV_FOREACH(q, p + 1)
 587                         if (strneq(*p, *q, n) && (*q)[n] == '=') {
 588                                 duplicate = true;
 589                                 break;
 590                         }
 591
 592                 if (duplicate) {
 593                         free(*p);
 594                         continue;
 595                 }
 596
 597                 e[k++] = *p;
 598         }
 599
 600         if (e)
 601                 e[k] = NULL;
 602
 603         return e;
 604 }
 605
 606 static int strv_extend_with_length(char ***l, const char *s, size_t n) {
 607         char *c;
 608
 609         c = strndup(s, n);
 610         if (!c)
 611                 return -ENOMEM;
 612
 613         return strv_consume(l, c);
 614 }
 615
 616 static int strv_env_get_n_validated(
 617                 char **env,
 618                 const char *name,
 619                 size_t l,
 620                 ReplaceEnvFlags flags,
 621                 char **ret,              /* points into the env block! do not free! */
 622                 char ***unset_variables, /* updated in place */
 623                 char ***bad_variables) { /* ditto */
 624
 625         char *e;
 626         int r;
 627
 628         assert(l == 0 || name);
 629         assert(ret);
 630
 631         if (env_name_is_valid_n(name, l)) {
 632                 e = strv_env_get_n(env, name, l, flags);
 633                 if (!e && unset_variables) {
 634                         r = strv_extend_with_length(unset_variables, name, l);
 635                         if (r < 0)
 636                                 return r;
 637                 }
 638         } else {
 639                 e = NULL; /* Resolve invalid variable names the same way as unset ones */
 640
 641                 if (bad_variables) {
 642                         r = strv_extend_with_length(bad_variables, name, l);
 643                         if (r < 0)
 644                                 return r;
 645                 }
 646         }
 647
 648         *ret = e;
 649         return !!e;
 650 }
 651
 652 int replace_env_full(
 653                 const char *format,
 654                 size_t n,
 655                 char **env,
 656                 ReplaceEnvFlags flags,
 657                 char **ret,
 658                 char ***ret_unset_variables,
 659                 char ***ret_bad_variables) {
 660
 661         enum {
 662                 WORD,
 663                 CURLY,
 664                 VARIABLE,
 665                 VARIABLE_RAW,
 666                 TEST,
 667                 DEFAULT_VALUE,
 668                 ALTERNATE_VALUE,
 669         } state = WORD;
 670
 671         _cleanup_strv_free_ char **unset_variables = NULL, **bad_variables = NULL;
 672         const char *e, *word = format, *test_value = NULL; /* test_value is initialized to appease gcc */
 673         _cleanup_free_ char *s = NULL;
 674         char ***pu, ***pb, *k;
 675         size_t i, len = 0; /* len is initialized to appease gcc */
 676         int nest = 0, r;
 677
 678         assert(format);
 679
 680         if (n == SIZE_MAX)
 681                 n = strlen(format);
 682
 683         pu = ret_unset_variables ? &unset_variables : NULL;
 684         pb = ret_bad_variables ? &bad_variables : NULL;
 685
 686         for (e = format, i = 0; *e && i < n; e ++, i ++)
 687                 switch (state) {
 688
 689                 case WORD:
 690                         if (*e == '$')
 691                                 state = CURLY;
 692                         break;
 693
 694                 case CURLY:
 695                         if (*e == '{') {
 696                                 k = strnappend(s, word, e-word-1);
 697                                 if (!k)
 698                                         return -ENOMEM;
 699
 700                                 free_and_replace(s, k);
 701
 702                                 word = e-1;
 703                                 state = VARIABLE;
 704                                 nest++;
 705
 706                         } else if (*e == '$') {
 707                                 k = strnappend(s, word, e-word);
 708                                 if (!k)
 709                                         return -ENOMEM;
 710
 711                                 free_and_replace(s, k);
 712
 713                                 word = e+1;
 714                                 state = WORD;
 715
 716                         } else if (FLAGS_SET(flags, REPLACE_ENV_ALLOW_BRACELESS) && strchr(VALID_BASH_ENV_NAME_CHARS, *e)) {
 717                                 k = strnappend(s, word, e-word-1);
 718                                 if (!k)
 719                                         return -ENOMEM;
 720
 721                                 free_and_replace(s, k);
 722
 723                                 word = e-1;
 724                                 state = VARIABLE_RAW;
 725
 726                         } else
 727                                 state = WORD;
 728                         break;
 729
 730                 case VARIABLE:
 731                         if (*e == '}') {
 732                                 char *t;
 733
 734                                 r = strv_env_get_n_validated(env, word+2, e-word-2, flags, &t, pu, pb);
 735                                 if (r < 0)
 736                                         return r;
 737
 738                                 if (!strextend(&s, t))
 739                                         return -ENOMEM;
 740
 741                                 word = e+1;
 742                                 state = WORD;
 743                                 nest--;
 744                         } else if (*e == ':') {
 745                                 if (flags & REPLACE_ENV_ALLOW_EXTENDED) {
 746                                         len = e - word - 2;
 747                                         state = TEST;
 748                                 } else
 749                                         /* Treat this as unsupported syntax, i.e. do no replacement */
 750                                         state = WORD;
 751                         }
 752                         break;
 753
 754                 case TEST:
 755                         if (*e == '-')
 756                                 state = DEFAULT_VALUE;
 757                         else if (*e == '+')
 758                                 state = ALTERNATE_VALUE;
 759                         else {
 760                                 state = WORD;
 761                                 break;
 762                         }
 763
 764                         test_value = e+1;
 765                         break;
 766
 767                 case DEFAULT_VALUE: /* fall through */
 768                 case ALTERNATE_VALUE:
 769                         assert(flags & REPLACE_ENV_ALLOW_EXTENDED);
 770
 771                         if (*e == '{') {
 772                                 nest++;
 773                                 break;
 774                         }
 775
 776                         if (*e != '}')
 777                                 break;
 778
 779                         nest--;
 780                         if (nest == 0) {
 781                                 _cleanup_strv_free_ char **u = NULL, **b = NULL;
 782                                 _cleanup_free_ char *v = NULL;
 783                                 char *t = NULL;
 784
 785                                 r = strv_env_get_n_validated(env, word+2, len, flags, &t, pu, pb);
 786                                 if (r < 0)
 787                                         return r;
 788
 789                                 if (t && state == ALTERNATE_VALUE) {
 790                                         r = replace_env_full(test_value, e-test_value, env, flags, &v, pu ? &u : NULL, pb ? &b : NULL);
 791                                         if (r < 0)
 792                                                 return r;
 793
 794                                         t = v;
 795                                 } else if (!t && state == DEFAULT_VALUE) {
 796                                         r = replace_env_full(test_value, e-test_value, env, flags, &v, pu ? &u : NULL, pb ? &b : NULL);
 797                                         if (r < 0)
 798                                                 return r;
 799
 800                                         t = v;
 801                                 }
 802
 803                                 r = strv_extend_strv(&unset_variables, u, /* filter_duplicates= */ true);
 804                                 if (r < 0)
 805                                         return r;
 806                                 r = strv_extend_strv(&bad_variables, b, /* filter_duplicates= */ true);
 807                                 if (r < 0)
 808                                         return r;
 809
 810                                 if (!strextend(&s, t))
 811                                         return -ENOMEM;
 812
 813                                 word = e+1;
 814                                 state = WORD;
 815                         }
 816                         break;
 817
 818                 case VARIABLE_RAW:
 819                         assert(flags & REPLACE_ENV_ALLOW_BRACELESS);
 820
 821                         if (!strchr(VALID_BASH_ENV_NAME_CHARS, *e)) {
 822                                 char *t = NULL;
 823
 824                                 r = strv_env_get_n_validated(env, word+1, e-word-1, flags, &t, &unset_variables, &bad_variables);
 825                                 if (r < 0)
 826                                         return r;
 827
 828                                 if (!strextend(&s, t))
 829                                         return -ENOMEM;
 830
 831                                 word = e--;
 832                                 i--;
 833                                 state = WORD;
 834                         }
 835                         break;
 836                 }
 837
 838         if (state == VARIABLE_RAW) {
 839                 char *t;
 840
 841                 assert(flags & REPLACE_ENV_ALLOW_BRACELESS);
 842
 843                 r = strv_env_get_n_validated(env, word+1, e-word-1, flags, &t, &unset_variables, &bad_variables);
 844                 if (r < 0)
 845                         return r;
 846
 847                 if (!strextend(&s, t))
 848                         return -ENOMEM;
 849
 850         } else if (!strextendn(&s, word, e-word))
 851                 return -ENOMEM;
 852
 853         if (ret_unset_variables)
 854                 *ret_unset_variables = TAKE_PTR(unset_variables);
 855         if (ret_bad_variables)
 856                 *ret_bad_variables = TAKE_PTR(bad_variables);
 857
 858         if (ret)
 859                 *ret = TAKE_PTR(s);
 860
 861         return 0;
 862 }
 863
 864 int replace_env_argv(
 865                 char **argv,
 866                 char **env,
 867                 char ***ret,
 868                 char ***ret_unset_variables,
 869                 char ***ret_bad_variables) {
 870
 871         _cleanup_strv_free_ char **n = NULL, **unset_variables = NULL, **bad_variables = NULL;
 872         size_t k = 0, l = 0;
 873         int r;
 874
 875         l = strv_length(argv);
 876
 877         n = new(char*, l+1);
 878         if (!n)
 879                 return -ENOMEM;
 880
 881         STRV_FOREACH(i, argv) {
 882                 const char *word = *i;
 883
 884                 /* If $FOO appears as single word, replace it by the split up variable */
 885                 if (word[0] == '$' && !IN_SET(word[1], '{', '$')) {
 886                         _cleanup_strv_free_ char **m = NULL;
 887                         const char *name = word + 1;
 888                         char *e, **w;
 889                         size_t q;
 890
 891                         if (env_name_is_valid(name)) {
 892                                 e = strv_env_get(env, name);
 893                                 if (e)
 894                                         r = strv_split_full(&m, e, WHITESPACE, EXTRACT_RELAX|EXTRACT_UNQUOTE);
 895                                 else if (ret_unset_variables)
 896                                         r = strv_extend(&unset_variables, name);
 897                                 else
 898                                         r = 0;
 899                         } else if (ret_bad_variables)
 900                                 r = strv_extend(&bad_variables, name);
 901                         else
 902                                 r = 0;
 903                         if (r < 0)
 904                                 return r;
 905
 906                         q = strv_length(m);
 907                         l = l + q - 1;
 908
 909                         w = reallocarray(n, l + 1, sizeof(char*));
 910                         if (!w)
 911                                 return -ENOMEM;
 912
 913                         n = w;
 914                         if (m) {
 915                                 memcpy(n + k, m, (q + 1) * sizeof(char*));
 916                                 m = mfree(m);
 917                         }
 918
 919                         k += q;
 920                         continue;
 921                 }
 922
 923                 _cleanup_strv_free_ char **u = NULL, **b = NULL;
 924
 925                 /* If ${FOO} appears as part of a word, replace it by the variable as-is */
 926                 r = replace_env_full(
 927                                 word,
 928                                 /* length= */ SIZE_MAX,
 929                                 env,
 930                                 /* flags= */ 0,
 931                                 n + k,
 932                                 ret_unset_variables ? &u : NULL,
 933                                 ret_bad_variables ? &b : NULL);
 934                 if (r < 0)
 935                         return r;
 936                 n[++k] = NULL;
 937
 938                 r = strv_extend_strv(&unset_variables, u, /* filter_duplicates= */ true);
 939                 if (r < 0)
 940                         return r;
 941
 942                 r = strv_extend_strv(&bad_variables, b, /*filter_duplicates= */ true);
 943                 if (r < 0)
 944                         return r;
 945         }
 946
 947         if (ret_unset_variables) {
 948                 strv_uniq(strv_sort(unset_variables));
 949                 *ret_unset_variables = TAKE_PTR(unset_variables);
 950         }
 951         if (ret_bad_variables) {
 952                 strv_uniq(strv_sort(bad_variables));
 953                 *ret_bad_variables = TAKE_PTR(bad_variables);
 954         }
 955
 956         *ret = TAKE_PTR(n);
 957         return 0;
 958 }
 959
 960 int getenv_bool(const char *p) {
 961         const char *e;
 962
 963         e = getenv(p);
 964         if (!e)
 965                 return -ENXIO;
 966
 967         return parse_boolean(e);
 968 }
 969
 970 int getenv_bool_secure(const char *p) {
 971         const char *e;
 972
 973         e = secure_getenv(p);
 974         if (!e)
 975                 return -ENXIO;
 976
 977         return parse_boolean(e);
 978 }
 979
 980 int getenv_uint64_secure(const char *p, uint64_t *ret) {
 981         const char *e;
 982
 983         assert(p);
 984
 985         e = secure_getenv(p);
 986         if (!e)
 987                 return -ENXIO;
 988
 989         return safe_atou64(e, ret);
 990 }
 991
 992 int set_unset_env(const char *name, const char *value, bool overwrite) {
 993         assert(name);
 994
 995         if (value)
 996                 return RET_NERRNO(setenv(name, value, overwrite));
 997
 998         return RET_NERRNO(unsetenv(name));
 999 }
1000
1001 int putenv_dup(const char *assignment, bool override) {
1002         const char *e, *n;
1003
1004         e = strchr(assignment, '=');
1005         if (!e)
1006                 return -EINVAL;
1007
1008         n = strndupa_safe(assignment, e - assignment);
1009
1010         /* This is like putenv(), but uses setenv() so that our memory doesn't become part of environ[]. */
1011         return RET_NERRNO(setenv(n, e + 1, override));
1012 }
1013
1014 int setenv_systemd_exec_pid(bool update_only) {
1015         char str[DECIMAL_STR_MAX(pid_t)];
1016         const char *e;
1017
1018         /* Update $SYSTEMD_EXEC_PID=pid except when '*' is set for the variable. */
1019
1020         e = secure_getenv("SYSTEMD_EXEC_PID");
1021         if (!e && update_only)
1022                 return 0;
1023
1024         if (streq_ptr(e, "*"))
1025                 return 0;
1026
1027         xsprintf(str, PID_FMT, getpid_cached());
1028
1029         if (setenv("SYSTEMD_EXEC_PID", str, 1) < 0)
1030                 return -errno;
1031
1032         return 1;
1033 }
1034
1035 int getenv_path_list(const char *name, char ***ret_paths) {
1036         _cleanup_strv_free_ char **l = NULL;
1037         const char *e;
1038         int r;
1039
1040         assert(name);
1041         assert(ret_paths);
1042
1043         e = secure_getenv(name);
1044         if (!e)
1045                 return -ENXIO;
1046
1047         r = strv_split_full(&l, e, ":", EXTRACT_DONT_COALESCE_SEPARATORS);
1048         if (r < 0)
1049                 return log_debug_errno(r, "Failed to parse $%s: %m", name);
1050
1051         STRV_FOREACH(p, l) {
1052                 if (!path_is_absolute(*p))
1053                         return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
1054                                                "Path '%s' is not absolute, refusing.", *p);
1055
1056                 if (!path_is_normalized(*p))
1057                         return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
1058                                                "Path '%s' is not normalized, refusing.", *p);
1059
1060                 if (path_equal(*p, "/"))
1061                         return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
1062                                                "Path '%s' is the root fs, refusing.", *p);
1063         }
1064
1065         if (strv_isempty(l))
1066                 return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
1067                                        "No paths specified, refusing.");
1068
1069         *ret_paths = TAKE_PTR(l);
1070         return 1;
1071 }
1072
1073 int getenv_steal_erase(const char *name, char **ret) {
1074         _cleanup_(erase_and_freep) char *a = NULL;
1075         char *e;
1076
1077         assert(name);
1078
1079         /* Reads an environment variable, makes a copy of it, erases its memory in the environment block and removes
1080          * it from there. Usecase: reading passwords from the env block (which is a bad idea, but useful for
1081          * testing, and given that people are likely going to misuse this, be thorough) */
1082
1083         e = getenv(name);
1084         if (!e) {
1085                 if (ret)
1086                         *ret = NULL;
1087                 return 0;
1088         }
1089
1090         if (ret) {
1091                 a = strdup(e);
1092                 if (!a)
1093                         return -ENOMEM;
1094         }
1095
1096         string_erase(e);
1097
1098         if (unsetenv(name) < 0)
1099                 return -errno;
1100
1101         if (ret)
1102                 *ret = TAKE_PTR(a);
1103
1104         return 1;
1105 }
1106
1107 int set_full_environment(char **env) {
1108         int r;
1109
1110         clearenv();
1111
1112         STRV_FOREACH(e, env) {
1113                 _cleanup_free_ char *k = NULL, *v = NULL;
1114
1115                 r = split_pair(*e, "=", &k, &v);
1116                 if (r < 0)
1117                         return r;
1118
1119                 if (setenv(k, v, /* overwrite= */ true) < 0)
1120                         return -errno;
1121         }
1122
1123         return 0;
1124 }