src/basic/fileio.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 <fcntl.h>
  22 #include <limits.h>
  23 #include <stdarg.h>
  24 #include <stdint.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27 #include <sys/stat.h>
  28 #include <sys/types.h>
  29 #include <unistd.h>
  30
  31 #include "alloc-util.h"
  32 #include "ctype.h"
  33 #include "env-util.h"
  34 #include "escape.h"
  35 #include "fd-util.h"
  36 #include "fileio.h"
  37 #include "fs-util.h"
  38 #include "hexdecoct.h"
  39 #include "log.h"
  40 #include "macro.h"
  41 #include "missing.h"
  42 #include "parse-util.h"
  43 #include "path-util.h"
  44 #include "process-util.h"
  45 #include "random-util.h"
  46 #include "stdio-util.h"
  47 #include "string-util.h"
  48 #include "strv.h"
  49 #include "time-util.h"
  50 #include "umask-util.h"
  51 #include "utf8.h"
  52
  53 #define READ_FULL_BYTES_MAX (4U*1024U*1024U)
  54
  55 int write_string_stream_ts(FILE *f, const char *line, bool enforce_newline, struct timespec *ts) {
  56
  57         assert(f);
  58         assert(line);
  59
  60         fputs(line, f);
  61         if (enforce_newline && !endswith(line, "\n"))
  62                 fputc('\n', f);
  63
  64         if (ts) {
  65                 struct timespec twice[2] = {*ts, *ts};
  66
  67                 if (futimens(fileno(f), twice) < 0)
  68                         return -errno;
  69         }
  70
  71         return fflush_and_check(f);
  72 }
  73
  74 static int write_string_file_atomic(
  75                 const char *fn,
  76                 const char *line,
  77                 bool enforce_newline,
  78                 bool do_fsync,
  79                 struct timespec *ts) {
  80
  81         _cleanup_fclose_ FILE *f = NULL;
  82         _cleanup_free_ char *p = NULL;
  83         int r;
  84
  85         assert(fn);
  86         assert(line);
  87
  88         r = fopen_temporary(fn, &f, &p);
  89         if (r < 0)
  90                 return r;
  91
  92         (void) fchmod_umask(fileno(f), 0644);
  93
  94         r = write_string_stream_ts(f, line, enforce_newline, ts);
  95         if (r >= 0 && do_fsync)
  96                 r = fflush_sync_and_check(f);
  97         if (r >= 0) {
  98                 if (rename(p, fn) < 0)
  99                         r = -errno;
 100         }
 101
 102         if (r < 0)
 103                 (void) unlink(p);
 104
 105         return r;
 106 }
 107
 108 int write_string_file_ts(const char *fn, const char *line, WriteStringFileFlags flags, struct timespec *ts) {
 109         _cleanup_fclose_ FILE *f = NULL;
 110         int q, r;
 111
 112         assert(fn);
 113         assert(line);
 114
 115         /* We don't know how to verify whether the file contents was already on-disk. */
 116         assert(!((flags & WRITE_STRING_FILE_VERIFY_ON_FAILURE) && (flags & WRITE_STRING_FILE_SYNC)));
 117
 118         if (flags & WRITE_STRING_FILE_ATOMIC) {
 119                 assert(flags & WRITE_STRING_FILE_CREATE);
 120
 121                 r = write_string_file_atomic(fn,
 122                                              line,
 123                                              !(flags & WRITE_STRING_FILE_AVOID_NEWLINE),
 124                                              flags & WRITE_STRING_FILE_SYNC, ts);
 125                 if (r < 0)
 126                         goto fail;
 127
 128                 return r;
 129         } else
 130                 assert(ts == NULL);
 131
 132         if (flags & WRITE_STRING_FILE_CREATE) {
 133                 f = fopen(fn, "we");
 134                 if (!f) {
 135                         r = -errno;
 136                         goto fail;
 137                 }
 138         } else {
 139                 int fd;
 140
 141                 /* We manually build our own version of fopen(..., "we") that
 142                  * works without O_CREAT */
 143                 fd = open(fn, O_WRONLY|O_CLOEXEC|O_NOCTTY);
 144                 if (fd < 0) {
 145                         r = -errno;
 146                         goto fail;
 147                 }
 148
 149                 f = fdopen(fd, "we");
 150                 if (!f) {
 151                         r = -errno;
 152                         safe_close(fd);
 153                         goto fail;
 154                 }
 155         }
 156
 157         r = write_string_stream_ts(f, line, !(flags & WRITE_STRING_FILE_AVOID_NEWLINE), ts);
 158         if (r < 0)
 159                 goto fail;
 160
 161         if (flags & WRITE_STRING_FILE_SYNC) {
 162                 r = fflush_sync_and_check(f);
 163                 if (r < 0)
 164                         return r;
 165         }
 166
 167         return 0;
 168
 169 fail:
 170         if (!(flags & WRITE_STRING_FILE_VERIFY_ON_FAILURE))
 171                 return r;
 172
 173         f = safe_fclose(f);
 174
 175         /* OK, the operation failed, but let's see if the right
 176          * contents in place already. If so, eat up the error. */
 177
 178         q = verify_file(fn, line, !(flags & WRITE_STRING_FILE_AVOID_NEWLINE));
 179         if (q <= 0)
 180                 return r;
 181
 182         return 0;
 183 }
 184
 185 int read_one_line_file(const char *fn, char **line) {
 186         _cleanup_fclose_ FILE *f = NULL;
 187         char t[LINE_MAX], *c;
 188
 189         assert(fn);
 190         assert(line);
 191
 192         f = fopen(fn, "re");
 193         if (!f)
 194                 return -errno;
 195
 196         if (!fgets(t, sizeof(t), f)) {
 197
 198                 if (ferror(f))
 199                         return errno > 0 ? -errno : -EIO;
 200
 201                 t[0] = 0;
 202         }
 203
 204         c = strdup(t);
 205         if (!c)
 206                 return -ENOMEM;
 207         truncate_nl(c);
 208
 209         *line = c;
 210         return 0;
 211 }
 212
 213 int verify_file(const char *fn, const char *blob, bool accept_extra_nl) {
 214         _cleanup_fclose_ FILE *f = NULL;
 215         _cleanup_free_ char *buf = NULL;
 216         size_t l, k;
 217
 218         assert(fn);
 219         assert(blob);
 220
 221         l = strlen(blob);
 222
 223         if (accept_extra_nl && endswith(blob, "\n"))
 224                 accept_extra_nl = false;
 225
 226         buf = malloc(l + accept_extra_nl + 1);
 227         if (!buf)
 228                 return -ENOMEM;
 229
 230         f = fopen(fn, "re");
 231         if (!f)
 232                 return -errno;
 233
 234         /* We try to read one byte more than we need, so that we know whether we hit eof */
 235         errno = 0;
 236         k = fread(buf, 1, l + accept_extra_nl + 1, f);
 237         if (ferror(f))
 238                 return errno > 0 ? -errno : -EIO;
 239
 240         if (k != l && k != l + accept_extra_nl)
 241                 return 0;
 242         if (memcmp(buf, blob, l) != 0)
 243                 return 0;
 244         if (k > l && buf[l] != '\n')
 245                 return 0;
 246
 247         return 1;
 248 }
 249
 250 int read_full_stream(FILE *f, char **contents, size_t *size) {
 251         size_t n, l;
 252         _cleanup_free_ char *buf = NULL;
 253         struct stat st;
 254
 255         assert(f);
 256         assert(contents);
 257
 258         if (fstat(fileno(f), &st) < 0)
 259                 return -errno;
 260
 261         n = LINE_MAX;
 262
 263         if (S_ISREG(st.st_mode)) {
 264
 265                 /* Safety check */
 266                 if (st.st_size > READ_FULL_BYTES_MAX)
 267                         return -E2BIG;
 268
 269                 /* Start with the right file size, but be prepared for
 270                  * files from /proc which generally report a file size
 271                  * of 0 */
 272                 if (st.st_size > 0)
 273                         n = st.st_size;
 274         }
 275
 276         l = 0;
 277         for (;;) {
 278                 char *t;
 279                 size_t k;
 280
 281                 t = realloc(buf, n + 1);
 282                 if (!t)
 283                         return -ENOMEM;
 284
 285                 buf = t;
 286                 k = fread(buf + l, 1, n - l, f);
 287                 if (k > 0)
 288                         l += k;
 289
 290                 if (ferror(f))
 291                         return -errno;
 292
 293                 if (feof(f))
 294                         break;
 295
 296                 /* We aren't expecting fread() to return a short read outside
 297                  * of (error && eof), assert buffer is full and enlarge buffer.
 298                  */
 299                 assert(l == n);
 300
 301                 /* Safety check */
 302                 if (n >= READ_FULL_BYTES_MAX)
 303                         return -E2BIG;
 304
 305                 n = MIN(n * 2, READ_FULL_BYTES_MAX);
 306         }
 307
 308         buf[l] = 0;
 309         *contents = buf;
 310         buf = NULL; /* do not free */
 311
 312         if (size)
 313                 *size = l;
 314
 315         return 0;
 316 }
 317
 318 int read_full_file(const char *fn, char **contents, size_t *size) {
 319         _cleanup_fclose_ FILE *f = NULL;
 320
 321         assert(fn);
 322         assert(contents);
 323
 324         f = fopen(fn, "re");
 325         if (!f)
 326                 return -errno;
 327
 328         return read_full_stream(f, contents, size);
 329 }
 330
 331 static int parse_env_file_internal(
 332                 FILE *f,
 333                 const char *fname,
 334                 const char *newline,
 335                 int (*push) (const char *filename, unsigned line,
 336                              const char *key, char *value, void *userdata, int *n_pushed),
 337                 void *userdata,
 338                 int *n_pushed) {
 339
 340         _cleanup_free_ char *contents = NULL, *key = NULL;
 341         size_t key_alloc = 0, n_key = 0, value_alloc = 0, n_value = 0, last_value_whitespace = (size_t) -1, last_key_whitespace = (size_t) -1;
 342         char *p, *value = NULL;
 343         int r;
 344         unsigned line = 1;
 345
 346         enum {
 347                 PRE_KEY,
 348                 KEY,
 349                 PRE_VALUE,
 350                 VALUE,
 351                 VALUE_ESCAPE,
 352                 SINGLE_QUOTE_VALUE,
 353                 SINGLE_QUOTE_VALUE_ESCAPE,
 354                 DOUBLE_QUOTE_VALUE,
 355                 DOUBLE_QUOTE_VALUE_ESCAPE,
 356                 COMMENT,
 357                 COMMENT_ESCAPE
 358         } state = PRE_KEY;
 359
 360         assert(newline);
 361
 362         if (f)
 363                 r = read_full_stream(f, &contents, NULL);
 364         else
 365                 r = read_full_file(fname, &contents, NULL);
 366         if (r < 0)
 367                 return r;
 368
 369         for (p = contents; *p; p++) {
 370                 char c = *p;
 371
 372                 switch (state) {
 373
 374                 case PRE_KEY:
 375                         if (strchr(COMMENTS, c))
 376                                 state = COMMENT;
 377                         else if (!strchr(WHITESPACE, c)) {
 378                                 state = KEY;
 379                                 last_key_whitespace = (size_t) -1;
 380
 381                                 if (!GREEDY_REALLOC(key, key_alloc, n_key+2)) {
 382                                         r = -ENOMEM;
 383                                         goto fail;
 384                                 }
 385
 386                                 key[n_key++] = c;
 387                         }
 388                         break;
 389
 390                 case KEY:
 391                         if (strchr(newline, c)) {
 392                                 state = PRE_KEY;
 393                                 line++;
 394                                 n_key = 0;
 395                         } else if (c == '=') {
 396                                 state = PRE_VALUE;
 397                                 last_value_whitespace = (size_t) -1;
 398                         } else {
 399                                 if (!strchr(WHITESPACE, c))
 400                                         last_key_whitespace = (size_t) -1;
 401                                 else if (last_key_whitespace == (size_t) -1)
 402                                          last_key_whitespace = n_key;
 403
 404                                 if (!GREEDY_REALLOC(key, key_alloc, n_key+2)) {
 405                                         r = -ENOMEM;
 406                                         goto fail;
 407                                 }
 408
 409                                 key[n_key++] = c;
 410                         }
 411
 412                         break;
 413
 414                 case PRE_VALUE:
 415                         if (strchr(newline, c)) {
 416                                 state = PRE_KEY;
 417                                 line++;
 418                                 key[n_key] = 0;
 419
 420                                 if (value)
 421                                         value[n_value] = 0;
 422
 423                                 /* strip trailing whitespace from key */
 424                                 if (last_key_whitespace != (size_t) -1)
 425                                         key[last_key_whitespace] = 0;
 426
 427                                 r = push(fname, line, key, value, userdata, n_pushed);
 428                                 if (r < 0)
 429                                         goto fail;
 430
 431                                 n_key = 0;
 432                                 value = NULL;
 433                                 value_alloc = n_value = 0;
 434
 435                         } else if (c == '\'')
 436                                 state = SINGLE_QUOTE_VALUE;
 437                         else if (c == '\"')
 438                                 state = DOUBLE_QUOTE_VALUE;
 439                         else if (c == '\\')
 440                                 state = VALUE_ESCAPE;
 441                         else if (!strchr(WHITESPACE, c)) {
 442                                 state = VALUE;
 443
 444                                 if (!GREEDY_REALLOC(value, value_alloc, n_value+2)) {
 445                                         r = -ENOMEM;
 446                                         goto fail;
 447                                 }
 448
 449                                 value[n_value++] = c;
 450                         }
 451
 452                         break;
 453
 454                 case VALUE:
 455                         if (strchr(newline, c)) {
 456                                 state = PRE_KEY;
 457                                 line++;
 458
 459                                 key[n_key] = 0;
 460
 461                                 if (value)
 462                                         value[n_value] = 0;
 463
 464                                 /* Chomp off trailing whitespace from value */
 465                                 if (last_value_whitespace != (size_t) -1)
 466                                         value[last_value_whitespace] = 0;
 467
 468                                 /* strip trailing whitespace from key */
 469                                 if (last_key_whitespace != (size_t) -1)
 470                                         key[last_key_whitespace] = 0;
 471
 472                                 r = push(fname, line, key, value, userdata, n_pushed);
 473                                 if (r < 0)
 474                                         goto fail;
 475
 476                                 n_key = 0;
 477                                 value = NULL;
 478                                 value_alloc = n_value = 0;
 479
 480                         } else if (c == '\\') {
 481                                 state = VALUE_ESCAPE;
 482                                 last_value_whitespace = (size_t) -1;
 483                         } else {
 484                                 if (!strchr(WHITESPACE, c))
 485                                         last_value_whitespace = (size_t) -1;
 486                                 else if (last_value_whitespace == (size_t) -1)
 487                                         last_value_whitespace = n_value;
 488
 489                                 if (!GREEDY_REALLOC(value, value_alloc, n_value+2)) {
 490                                         r = -ENOMEM;
 491                                         goto fail;
 492                                 }
 493
 494                                 value[n_value++] = c;
 495                         }
 496
 497                         break;
 498
 499                 case VALUE_ESCAPE:
 500                         state = VALUE;
 501
 502                         if (!strchr(newline, c)) {
 503                                 /* Escaped newlines we eat up entirely */
 504                                 if (!GREEDY_REALLOC(value, value_alloc, n_value+2)) {
 505                                         r = -ENOMEM;
 506                                         goto fail;
 507                                 }
 508
 509                                 value[n_value++] = c;
 510                         }
 511                         break;
 512
 513                 case SINGLE_QUOTE_VALUE:
 514                         if (c == '\'')
 515                                 state = PRE_VALUE;
 516                         else if (c == '\\')
 517                                 state = SINGLE_QUOTE_VALUE_ESCAPE;
 518                         else {
 519                                 if (!GREEDY_REALLOC(value, value_alloc, n_value+2)) {
 520                                         r = -ENOMEM;
 521                                         goto fail;
 522                                 }
 523
 524                                 value[n_value++] = c;
 525                         }
 526
 527                         break;
 528
 529                 case SINGLE_QUOTE_VALUE_ESCAPE:
 530                         state = SINGLE_QUOTE_VALUE;
 531
 532                         if (!strchr(newline, c)) {
 533                                 if (!GREEDY_REALLOC(value, value_alloc, n_value+2)) {
 534                                         r = -ENOMEM;
 535                                         goto fail;
 536                                 }
 537
 538                                 value[n_value++] = c;
 539                         }
 540                         break;
 541
 542                 case DOUBLE_QUOTE_VALUE:
 543                         if (c == '\"')
 544                                 state = PRE_VALUE;
 545                         else if (c == '\\')
 546                                 state = DOUBLE_QUOTE_VALUE_ESCAPE;
 547                         else {
 548                                 if (!GREEDY_REALLOC(value, value_alloc, n_value+2)) {
 549                                         r = -ENOMEM;
 550                                         goto fail;
 551                                 }
 552
 553                                 value[n_value++] = c;
 554                         }
 555
 556                         break;
 557
 558                 case DOUBLE_QUOTE_VALUE_ESCAPE:
 559                         state = DOUBLE_QUOTE_VALUE;
 560
 561                         if (!strchr(newline, c)) {
 562                                 if (!GREEDY_REALLOC(value, value_alloc, n_value+2)) {
 563                                         r = -ENOMEM;
 564                                         goto fail;
 565                                 }
 566
 567                                 value[n_value++] = c;
 568                         }
 569                         break;
 570
 571                 case COMMENT:
 572                         if (c == '\\')
 573                                 state = COMMENT_ESCAPE;
 574                         else if (strchr(newline, c)) {
 575                                 state = PRE_KEY;
 576                                 line++;
 577                         }
 578                         break;
 579
 580                 case COMMENT_ESCAPE:
 581                         state = COMMENT;
 582                         break;
 583                 }
 584         }
 585
 586         if (IN_SET(state,
 587                    PRE_VALUE,
 588                    VALUE,
 589                    VALUE_ESCAPE,
 590                    SINGLE_QUOTE_VALUE,
 591                    SINGLE_QUOTE_VALUE_ESCAPE,
 592                    DOUBLE_QUOTE_VALUE,
 593                    DOUBLE_QUOTE_VALUE_ESCAPE)) {
 594
 595                 key[n_key] = 0;
 596
 597                 if (value)
 598                         value[n_value] = 0;
 599
 600                 if (state == VALUE)
 601                         if (last_value_whitespace != (size_t) -1)
 602                                 value[last_value_whitespace] = 0;
 603
 604                 /* strip trailing whitespace from key */
 605                 if (last_key_whitespace != (size_t) -1)
 606                         key[last_key_whitespace] = 0;
 607
 608                 r = push(fname, line, key, value, userdata, n_pushed);
 609                 if (r < 0)
 610                         goto fail;
 611         }
 612
 613         return 0;
 614
 615 fail:
 616         free(value);
 617         return r;
 618 }
 619
 620 static int check_utf8ness_and_warn(
 621                 const char *filename, unsigned line,
 622                 const char *key, char *value) {
 623
 624         if (!utf8_is_valid(key)) {
 625                 _cleanup_free_ char *p = NULL;
 626
 627                 p = utf8_escape_invalid(key);
 628                 log_error("%s:%u: invalid UTF-8 in key '%s', ignoring.", strna(filename), line, p);
 629                 return -EINVAL;
 630         }
 631
 632         if (value && !utf8_is_valid(value)) {
 633                 _cleanup_free_ char *p = NULL;
 634
 635                 p = utf8_escape_invalid(value);
 636                 log_error("%s:%u: invalid UTF-8 value for key %s: '%s', ignoring.", strna(filename), line, key, p);
 637                 return -EINVAL;
 638         }
 639
 640         return 0;
 641 }
 642
 643 static int parse_env_file_push(
 644                 const char *filename, unsigned line,
 645                 const char *key, char *value,
 646                 void *userdata,
 647                 int *n_pushed) {
 648
 649         const char *k;
 650         va_list aq, *ap = userdata;
 651         int r;
 652
 653         r = check_utf8ness_and_warn(filename, line, key, value);
 654         if (r < 0)
 655                 return r;
 656
 657         va_copy(aq, *ap);
 658
 659         while ((k = va_arg(aq, const char *))) {
 660                 char **v;
 661
 662                 v = va_arg(aq, char **);
 663
 664                 if (streq(key, k)) {
 665                         va_end(aq);
 666                         free(*v);
 667                         *v = value;
 668
 669                         if (n_pushed)
 670                                 (*n_pushed)++;
 671
 672                         return 1;
 673                 }
 674         }
 675
 676         va_end(aq);
 677         free(value);
 678
 679         return 0;
 680 }
 681
 682 int parse_env_file(
 683                 const char *fname,
 684                 const char *newline, ...) {
 685
 686         va_list ap;
 687         int r, n_pushed = 0;
 688
 689         if (!newline)
 690                 newline = NEWLINE;
 691
 692         va_start(ap, newline);
 693         r = parse_env_file_internal(NULL, fname, newline, parse_env_file_push, &ap, &n_pushed);
 694         va_end(ap);
 695
 696         return r < 0 ? r : n_pushed;
 697 }
 698
 699 static int load_env_file_push(
 700                 const char *filename, unsigned line,
 701                 const char *key, char *value,
 702                 void *userdata,
 703                 int *n_pushed) {
 704         char ***m = userdata;
 705         char *p;
 706         int r;
 707
 708         r = check_utf8ness_and_warn(filename, line, key, value);
 709         if (r < 0)
 710                 return r;
 711
 712         p = strjoin(key, "=", value);
 713         if (!p)
 714                 return -ENOMEM;
 715
 716         r = strv_env_replace(m, p);
 717         if (r < 0) {
 718                 free(p);
 719                 return r;
 720         }
 721
 722         if (n_pushed)
 723                 (*n_pushed)++;
 724
 725         free(value);
 726         return 0;
 727 }
 728
 729 int load_env_file(FILE *f, const char *fname, const char *newline, char ***rl) {
 730         char **m = NULL;
 731         int r;
 732
 733         if (!newline)
 734                 newline = NEWLINE;
 735
 736         r = parse_env_file_internal(f, fname, newline, load_env_file_push, &m, NULL);
 737         if (r < 0) {
 738                 strv_free(m);
 739                 return r;
 740         }
 741
 742         *rl = m;
 743         return 0;
 744 }
 745
 746 static int load_env_file_push_pairs(
 747                 const char *filename, unsigned line,
 748                 const char *key, char *value,
 749                 void *userdata,
 750                 int *n_pushed) {
 751         char ***m = userdata;
 752         int r;
 753
 754         r = check_utf8ness_and_warn(filename, line, key, value);
 755         if (r < 0)
 756                 return r;
 757
 758         r = strv_extend(m, key);
 759         if (r < 0)
 760                 return -ENOMEM;
 761
 762         if (!value) {
 763                 r = strv_extend(m, "");
 764                 if (r < 0)
 765                         return -ENOMEM;
 766         } else {
 767                 r = strv_push(m, value);
 768                 if (r < 0)
 769                         return r;
 770         }
 771
 772         if (n_pushed)
 773                 (*n_pushed)++;
 774
 775         return 0;
 776 }
 777
 778 int load_env_file_pairs(FILE *f, const char *fname, const char *newline, char ***rl) {
 779         char **m = NULL;
 780         int r;
 781
 782         if (!newline)
 783                 newline = NEWLINE;
 784
 785         r = parse_env_file_internal(f, fname, newline, load_env_file_push_pairs, &m, NULL);
 786         if (r < 0) {
 787                 strv_free(m);
 788                 return r;
 789         }
 790
 791         *rl = m;
 792         return 0;
 793 }
 794
 795 static int merge_env_file_push(
 796                 const char *filename, unsigned line,
 797                 const char *key, char *value,
 798                 void *userdata,
 799                 int *n_pushed) {
 800
 801         char ***env = userdata;
 802         char *expanded_value;
 803
 804         assert(env);
 805
 806         if (!value) {
 807                 log_error("%s:%u: invalid syntax (around \"%s\"), ignoring.", strna(filename), line, key);
 808                 return 0;
 809         }
 810
 811         if (!env_name_is_valid(key)) {
 812                 log_error("%s:%u: invalid variable name \"%s\", ignoring.", strna(filename), line, key);
 813                 free(value);
 814                 return 0;
 815         }
 816
 817         expanded_value = replace_env(value, *env,
 818                                      REPLACE_ENV_USE_ENVIRONMENT|
 819                                      REPLACE_ENV_ALLOW_BRACELESS|
 820                                      REPLACE_ENV_ALLOW_EXTENDED);
 821         if (!expanded_value)
 822                 return -ENOMEM;
 823
 824         free_and_replace(value, expanded_value);
 825
 826         return load_env_file_push(filename, line, key, value, env, n_pushed);
 827 }
 828
 829 int merge_env_file(
 830                 char ***env,
 831                 FILE *f,
 832                 const char *fname) {
 833
 834         /* NOTE: this function supports braceful and braceless variable expansions,
 835          * plus "extended" substitutions, unlike other exported parsing functions.
 836          */
 837
 838         return parse_env_file_internal(f, fname, NEWLINE, merge_env_file_push, env, NULL);
 839 }
 840
 841 static void write_env_var(FILE *f, const char *v) {
 842         const char *p;
 843
 844         p = strchr(v, '=');
 845         if (!p) {
 846                 /* Fallback */
 847                 fputs_unlocked(v, f);
 848                 fputc_unlocked('\n', f);
 849                 return;
 850         }
 851
 852         p++;
 853         fwrite_unlocked(v, 1, p-v, f);
 854
 855         if (string_has_cc(p, NULL) || chars_intersect(p, WHITESPACE SHELL_NEED_QUOTES)) {
 856                 fputc_unlocked('\"', f);
 857
 858                 for (; *p; p++) {
 859                         if (strchr(SHELL_NEED_ESCAPE, *p))
 860                                 fputc_unlocked('\\', f);
 861
 862                         fputc_unlocked(*p, f);
 863                 }
 864
 865                 fputc_unlocked('\"', f);
 866         } else
 867                 fputs_unlocked(p, f);
 868
 869         fputc_unlocked('\n', f);
 870 }
 871
 872 int write_env_file(const char *fname, char **l) {
 873         _cleanup_fclose_ FILE *f = NULL;
 874         _cleanup_free_ char *p = NULL;
 875         char **i;
 876         int r;
 877
 878         assert(fname);
 879
 880         r = fopen_temporary(fname, &f, &p);
 881         if (r < 0)
 882                 return r;
 883
 884         fchmod_umask(fileno(f), 0644);
 885
 886         STRV_FOREACH(i, l)
 887                 write_env_var(f, *i);
 888
 889         r = fflush_and_check(f);
 890         if (r >= 0) {
 891                 if (rename(p, fname) >= 0)
 892                         return 0;
 893
 894                 r = -errno;
 895         }
 896
 897         unlink(p);
 898         return r;
 899 }
 900
 901 int executable_is_script(const char *path, char **interpreter) {
 902         int r;
 903         _cleanup_free_ char *line = NULL;
 904         int len;
 905         char *ans;
 906
 907         assert(path);
 908
 909         r = read_one_line_file(path, &line);
 910         if (r < 0)
 911                 return r;
 912
 913         if (!startswith(line, "#!"))
 914                 return 0;
 915
 916         ans = strstrip(line + 2);
 917         len = strcspn(ans, " \t");
 918
 919         if (len == 0)
 920                 return 0;
 921
 922         ans = strndup(ans, len);
 923         if (!ans)
 924                 return -ENOMEM;
 925
 926         *interpreter = ans;
 927         return 1;
 928 }
 929
 930 /**
 931  * Retrieve one field from a file like /proc/self/status.  pattern
 932  * should not include whitespace or the delimiter (':'). pattern matches only
 933  * the beginning of a line. Whitespace before ':' is skipped. Whitespace and
 934  * zeros after the ':' will be skipped. field must be freed afterwards.
 935  * terminator specifies the terminating characters of the field value (not
 936  * included in the value).
 937  */
 938 int get_proc_field(const char *filename, const char *pattern, const char *terminator, char **field) {
 939         _cleanup_free_ char *status = NULL;
 940         char *t, *f;
 941         size_t len;
 942         int r;
 943
 944         assert(terminator);
 945         assert(filename);
 946         assert(pattern);
 947         assert(field);
 948
 949         r = read_full_file(filename, &status, NULL);
 950         if (r < 0)
 951                 return r;
 952
 953         t = status;
 954
 955         do {
 956                 bool pattern_ok;
 957
 958                 do {
 959                         t = strstr(t, pattern);
 960                         if (!t)
 961                                 return -ENOENT;
 962
 963                         /* Check that pattern occurs in beginning of line. */
 964                         pattern_ok = (t == status || t[-1] == '\n');
 965
 966                         t += strlen(pattern);
 967
 968                 } while (!pattern_ok);
 969
 970                 t += strspn(t, " \t");
 971                 if (!*t)
 972                         return -ENOENT;
 973
 974         } while (*t != ':');
 975
 976         t++;
 977
 978         if (*t) {
 979                 t += strspn(t, " \t");
 980
 981                 /* Also skip zeros, because when this is used for
 982                  * capabilities, we don't want the zeros. This way the
 983                  * same capability set always maps to the same string,
 984                  * irrespective of the total capability set size. For
 985                  * other numbers it shouldn't matter. */
 986                 t += strspn(t, "0");
 987                 /* Back off one char if there's nothing but whitespace
 988                    and zeros */
 989                 if (!*t || isspace(*t))
 990                         t--;
 991         }
 992
 993         len = strcspn(t, terminator);
 994
 995         f = strndup(t, len);
 996         if (!f)
 997                 return -ENOMEM;
 998
 999         *field = f;
1000         return 0;
1001 }
1002
1003 DIR *xopendirat(int fd, const char *name, int flags) {
1004         int nfd;
1005         DIR *d;
1006
1007         assert(!(flags & O_CREAT));
1008
1009         nfd = openat(fd, name, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|flags, 0);
1010         if (nfd < 0)
1011                 return NULL;
1012
1013         d = fdopendir(nfd);
1014         if (!d) {
1015                 safe_close(nfd);
1016                 return NULL;
1017         }
1018
1019         return d;
1020 }
1021
1022 static int search_and_fopen_internal(const char *path, const char *mode, const char *root, char **search, FILE **_f) {
1023         char **i;
1024
1025         assert(path);
1026         assert(mode);
1027         assert(_f);
1028
1029         if (!path_strv_resolve_uniq(search, root))
1030                 return -ENOMEM;
1031
1032         STRV_FOREACH(i, search) {
1033                 _cleanup_free_ char *p = NULL;
1034                 FILE *f;
1035
1036                 if (root)
1037                         p = strjoin(root, *i, "/", path);
1038                 else
1039                         p = strjoin(*i, "/", path);
1040                 if (!p)
1041                         return -ENOMEM;
1042
1043                 f = fopen(p, mode);
1044                 if (f) {
1045                         *_f = f;
1046                         return 0;
1047                 }
1048
1049                 if (errno != ENOENT)
1050                         return -errno;
1051         }
1052
1053         return -ENOENT;
1054 }
1055
1056 int search_and_fopen(const char *path, const char *mode, const char *root, const char **search, FILE **_f) {
1057         _cleanup_strv_free_ char **copy = NULL;
1058
1059         assert(path);
1060         assert(mode);
1061         assert(_f);
1062
1063         if (path_is_absolute(path)) {
1064                 FILE *f;
1065
1066                 f = fopen(path, mode);
1067                 if (f) {
1068                         *_f = f;
1069                         return 0;
1070                 }
1071
1072                 return -errno;
1073         }
1074
1075         copy = strv_copy((char**) search);
1076         if (!copy)
1077                 return -ENOMEM;
1078
1079         return search_and_fopen_internal(path, mode, root, copy, _f);
1080 }
1081
1082 int search_and_fopen_nulstr(const char *path, const char *mode, const char *root, const char *search, FILE **_f) {
1083         _cleanup_strv_free_ char **s = NULL;
1084
1085         if (path_is_absolute(path)) {
1086                 FILE *f;
1087
1088                 f = fopen(path, mode);
1089                 if (f) {
1090                         *_f = f;
1091                         return 0;
1092                 }
1093
1094                 return -errno;
1095         }
1096
1097         s = strv_split_nulstr(search);
1098         if (!s)
1099                 return -ENOMEM;
1100
1101         return search_and_fopen_internal(path, mode, root, s, _f);
1102 }
1103
1104 int fopen_temporary(const char *path, FILE **_f, char **_temp_path) {
1105         FILE *f;
1106         char *t;
1107         int r, fd;
1108
1109         assert(path);
1110         assert(_f);
1111         assert(_temp_path);
1112
1113         r = tempfn_xxxxxx(path, NULL, &t);
1114         if (r < 0)
1115                 return r;
1116
1117         fd = mkostemp_safe(t);
1118         if (fd < 0) {
1119                 free(t);
1120                 return -errno;
1121         }
1122
1123         f = fdopen(fd, "we");
1124         if (!f) {
1125                 unlink_noerrno(t);
1126                 free(t);
1127                 safe_close(fd);
1128                 return -errno;
1129         }
1130
1131         *_f = f;
1132         *_temp_path = t;
1133
1134         return 0;
1135 }
1136
1137 int fflush_and_check(FILE *f) {
1138         assert(f);
1139
1140         errno = 0;
1141         fflush(f);
1142
1143         if (ferror(f))
1144                 return errno > 0 ? -errno : -EIO;
1145
1146         return 0;
1147 }
1148
1149 int fflush_sync_and_check(FILE *f) {
1150         int r;
1151
1152         assert(f);
1153
1154         r = fflush_and_check(f);
1155         if (r < 0)
1156                 return r;
1157
1158         if (fsync(fileno(f)) < 0)
1159                 return -errno;
1160
1161         return 0;
1162 }
1163
1164 /* This is much like mkostemp() but is subject to umask(). */
1165 int mkostemp_safe(char *pattern) {
1166         _cleanup_umask_ mode_t u = 0;
1167         int fd;
1168
1169         assert(pattern);
1170
1171         u = umask(077);
1172
1173         fd = mkostemp(pattern, O_CLOEXEC);
1174         if (fd < 0)
1175                 return -errno;
1176
1177         return fd;
1178 }
1179
1180 int tempfn_xxxxxx(const char *p, const char *extra, char **ret) {
1181         const char *fn;
1182         char *t;
1183
1184         assert(p);
1185         assert(ret);
1186
1187         /*
1188          * Turns this:
1189          *         /foo/bar/waldo
1190          *
1191          * Into this:
1192          *         /foo/bar/.#<extra>waldoXXXXXX
1193          */
1194
1195         fn = basename(p);
1196         if (!filename_is_valid(fn))
1197                 return -EINVAL;
1198
1199         if (extra == NULL)
1200                 extra = "";
1201
1202         t = new(char, strlen(p) + 2 + strlen(extra) + 6 + 1);
1203         if (!t)
1204                 return -ENOMEM;
1205
1206         strcpy(stpcpy(stpcpy(stpcpy(mempcpy(t, p, fn - p), ".#"), extra), fn), "XXXXXX");
1207
1208         *ret = path_kill_slashes(t);
1209         return 0;
1210 }
1211
1212 int tempfn_random(const char *p, const char *extra, char **ret) {
1213         const char *fn;
1214         char *t, *x;
1215         uint64_t u;
1216         unsigned i;
1217
1218         assert(p);
1219         assert(ret);
1220
1221         /*
1222          * Turns this:
1223          *         /foo/bar/waldo
1224          *
1225          * Into this:
1226          *         /foo/bar/.#<extra>waldobaa2a261115984a9
1227          */
1228
1229         fn = basename(p);
1230         if (!filename_is_valid(fn))
1231                 return -EINVAL;
1232
1233         if (!extra)
1234                 extra = "";
1235
1236         t = new(char, strlen(p) + 2 + strlen(extra) + 16 + 1);
1237         if (!t)
1238                 return -ENOMEM;
1239
1240         x = stpcpy(stpcpy(stpcpy(mempcpy(t, p, fn - p), ".#"), extra), fn);
1241
1242         u = random_u64();
1243         for (i = 0; i < 16; i++) {
1244                 *(x++) = hexchar(u & 0xF);
1245                 u >>= 4;
1246         }
1247
1248         *x = 0;
1249
1250         *ret = path_kill_slashes(t);
1251         return 0;
1252 }
1253
1254 int tempfn_random_child(const char *p, const char *extra, char **ret) {
1255         char *t, *x;
1256         uint64_t u;
1257         unsigned i;
1258         int r;
1259
1260         assert(ret);
1261
1262         /* Turns this:
1263          *         /foo/bar/waldo
1264          * Into this:
1265          *         /foo/bar/waldo/.#<extra>3c2b6219aa75d7d0
1266          */
1267
1268         if (!p) {
1269                 r = tmp_dir(&p);
1270                 if (r < 0)
1271                         return r;
1272         }
1273
1274         if (!extra)
1275                 extra = "";
1276
1277         t = new(char, strlen(p) + 3 + strlen(extra) + 16 + 1);
1278         if (!t)
1279                 return -ENOMEM;
1280
1281         x = stpcpy(stpcpy(stpcpy(t, p), "/.#"), extra);
1282
1283         u = random_u64();
1284         for (i = 0; i < 16; i++) {
1285                 *(x++) = hexchar(u & 0xF);
1286                 u >>= 4;
1287         }
1288
1289         *x = 0;
1290
1291         *ret = path_kill_slashes(t);
1292         return 0;
1293 }
1294
1295 int write_timestamp_file_atomic(const char *fn, usec_t n) {
1296         char ln[DECIMAL_STR_MAX(n)+2];
1297
1298         /* Creates a "timestamp" file, that contains nothing but a
1299          * usec_t timestamp, formatted in ASCII. */
1300
1301         if (n <= 0 || n >= USEC_INFINITY)
1302                 return -ERANGE;
1303
1304         xsprintf(ln, USEC_FMT "\n", n);
1305
1306         return write_string_file(fn, ln, WRITE_STRING_FILE_CREATE|WRITE_STRING_FILE_ATOMIC);
1307 }
1308
1309 int read_timestamp_file(const char *fn, usec_t *ret) {
1310         _cleanup_free_ char *ln = NULL;
1311         uint64_t t;
1312         int r;
1313
1314         r = read_one_line_file(fn, &ln);
1315         if (r < 0)
1316                 return r;
1317
1318         r = safe_atou64(ln, &t);
1319         if (r < 0)
1320                 return r;
1321
1322         if (t <= 0 || t >= (uint64_t) USEC_INFINITY)
1323                 return -ERANGE;
1324
1325         *ret = (usec_t) t;
1326         return 0;
1327 }
1328
1329 int fputs_with_space(FILE *f, const char *s, const char *separator, bool *space) {
1330         int r;
1331
1332         assert(s);
1333
1334         /* Outputs the specified string with fputs(), but optionally prefixes it with a separator. The *space parameter
1335          * when specified shall initially point to a boolean variable initialized to false. It is set to true after the
1336          * first invocation. This call is supposed to be use in loops, where a separator shall be inserted between each
1337          * element, but not before the first one. */
1338
1339         if (!f)
1340                 f = stdout;
1341
1342         if (space) {
1343                 if (!separator)
1344                         separator = " ";
1345
1346                 if (*space) {
1347                         r = fputs(separator, f);
1348                         if (r < 0)
1349                                 return r;
1350                 }
1351
1352                 *space = true;
1353         }
1354
1355         return fputs(s, f);
1356 }
1357
1358 int open_tmpfile_unlinkable(const char *directory, int flags) {
1359         char *p;
1360         int fd, r;
1361
1362         if (!directory) {
1363                 r = tmp_dir(&directory);
1364                 if (r < 0)
1365                         return r;
1366         }
1367
1368         /* Returns an unlinked temporary file that cannot be linked into the file system anymore */
1369
1370         /* Try O_TMPFILE first, if it is supported */
1371         fd = open(directory, flags|O_TMPFILE|O_EXCL, S_IRUSR|S_IWUSR);
1372         if (fd >= 0)
1373                 return fd;
1374
1375         /* Fall back to unguessable name + unlinking */
1376         p = strjoina(directory, "/systemd-tmp-XXXXXX");
1377
1378         fd = mkostemp_safe(p);
1379         if (fd < 0)
1380                 return fd;
1381
1382         (void) unlink(p);
1383
1384         return fd;
1385 }
1386
1387 int open_tmpfile_linkable(const char *target, int flags, char **ret_path) {
1388         _cleanup_free_ char *tmp = NULL;
1389         int r, fd;
1390
1391         assert(target);
1392         assert(ret_path);
1393
1394         /* Don't allow O_EXCL, as that has a special meaning for O_TMPFILE */
1395         assert((flags & O_EXCL) == 0);
1396
1397         /* Creates a temporary file, that shall be renamed to "target" later. If possible, this uses O_TMPFILE – in
1398          * which case "ret_path" will be returned as NULL. If not possible a the tempoary path name used is returned in
1399          * "ret_path". Use link_tmpfile() below to rename the result after writing the file in full. */
1400
1401         {
1402                 _cleanup_free_ char *dn = NULL;
1403
1404                 dn = dirname_malloc(target);
1405                 if (!dn)
1406                         return -ENOMEM;
1407
1408                 fd = open(dn, O_TMPFILE|flags, 0640);
1409                 if (fd >= 0) {
1410                         *ret_path = NULL;
1411                         return fd;
1412                 }
1413
1414                 log_debug_errno(errno, "Failed to use O_TMPFILE on %s: %m", dn);
1415         }
1416
1417         r = tempfn_random(target, NULL, &tmp);
1418         if (r < 0)
1419                 return r;
1420
1421         fd = open(tmp, O_CREAT|O_EXCL|O_NOFOLLOW|O_NOCTTY|flags, 0640);
1422         if (fd < 0)
1423                 return -errno;
1424
1425         *ret_path = tmp;
1426         tmp = NULL;
1427
1428         return fd;
1429 }
1430
1431 int open_serialization_fd(const char *ident) {
1432         int fd = -1;
1433
1434         fd = memfd_create(ident, MFD_CLOEXEC);
1435         if (fd < 0) {
1436                 const char *path;
1437
1438                 path = getpid_cached() == 1 ? "/run/systemd" : "/tmp";
1439                 fd = open_tmpfile_unlinkable(path, O_RDWR|O_CLOEXEC);
1440                 if (fd < 0)
1441                         return fd;
1442
1443                 log_debug("Serializing %s to %s.", ident, path);
1444         } else
1445                 log_debug("Serializing %s to memfd.", ident);
1446
1447         return fd;
1448 }
1449
1450 int link_tmpfile(int fd, const char *path, const char *target) {
1451
1452         assert(fd >= 0);
1453         assert(target);
1454
1455         /* Moves a temporary file created with open_tmpfile() above into its final place. if "path" is NULL an fd
1456          * created with O_TMPFILE is assumed, and linkat() is used. Otherwise it is assumed O_TMPFILE is not supported
1457          * on the directory, and renameat2() is used instead.
1458          *
1459          * Note that in both cases we will not replace existing files. This is because linkat() does not support this
1460          * operation currently (renameat2() does), and there is no nice way to emulate this. */
1461
1462         if (path) {
1463                 if (rename_noreplace(AT_FDCWD, path, AT_FDCWD, target) < 0)
1464                         return -errno;
1465         } else {
1466                 char proc_fd_path[strlen("/proc/self/fd/") + DECIMAL_STR_MAX(fd) + 1];
1467
1468                 xsprintf(proc_fd_path, "/proc/self/fd/%i", fd);
1469
1470                 if (linkat(AT_FDCWD, proc_fd_path, AT_FDCWD, target, AT_SYMLINK_FOLLOW) < 0)
1471                         return -errno;
1472         }
1473
1474         return 0;
1475 }
1476
1477 int read_nul_string(FILE *f, char **ret) {
1478         _cleanup_free_ char *x = NULL;
1479         size_t allocated = 0, n = 0;
1480
1481         assert(f);
1482         assert(ret);
1483
1484         /* Reads a NUL-terminated string from the specified file. */
1485
1486         for (;;) {
1487                 int c;
1488
1489                 if (!GREEDY_REALLOC(x, allocated, n+2))
1490                         return -ENOMEM;
1491
1492                 c = fgetc(f);
1493                 if (c == 0) /* Terminate at NUL byte */
1494                         break;
1495                 if (c == EOF) {
1496                         if (ferror(f))
1497                                 return -errno;
1498                         break; /* Terminate at EOF */
1499                 }
1500
1501                 x[n++] = (char) c;
1502         }
1503
1504         if (x)
1505                 x[n] = 0;
1506         else {
1507                 x = new0(char, 1);
1508                 if (!x)
1509                         return -ENOMEM;
1510         }
1511
1512         *ret = x;
1513         x = NULL;
1514
1515         return 0;
1516 }
1517
1518 int mkdtemp_malloc(const char *template, char **ret) {
1519         char *p;
1520
1521         assert(template);
1522         assert(ret);
1523
1524         p = strdup(template);
1525         if (!p)
1526                 return -ENOMEM;
1527
1528         if (!mkdtemp(p)) {
1529                 free(p);
1530                 return -errno;
1531         }
1532
1533         *ret = p;
1534         return 0;
1535 }