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