src/basic/fileio.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #include <errno.h>
   4 #include <fcntl.h>
   5 #include <limits.h>
   6 #include <stdarg.h>
   7 #include <stdint.h>
   8 #include <stdio_ext.h>
   9 #include <stdlib.h>
  10 #include <string.h>
  11 #include <sys/mman.h>
  12 #include <sys/stat.h>
  13 #include <sys/types.h>
  14 #include <unistd.h>
  15
  16 #include "alloc-util.h"
  17 #include "ctype.h"
  18 #include "def.h"
  19 #include "env-util.h"
  20 #include "escape.h"
  21 #include "fd-util.h"
  22 #include "fileio.h"
  23 #include "fs-util.h"
  24 #include "hexdecoct.h"
  25 #include "log.h"
  26 #include "macro.h"
  27 #include "missing.h"
  28 #include "parse-util.h"
  29 #include "path-util.h"
  30 #include "process-util.h"
  31 #include "random-util.h"
  32 #include "stdio-util.h"
  33 #include "string-util.h"
  34 #include "strv.h"
  35 #include "time-util.h"
  36 #include "umask-util.h"
  37 #include "utf8.h"
  38
  39 #define READ_FULL_BYTES_MAX (4U*1024U*1024U)
  40
  41 int write_string_stream_ts(
  42                 FILE *f,
  43                 const char *line,
  44                 WriteStringFileFlags flags,
  45                 struct timespec *ts) {
  46
  47         bool needs_nl;
  48         int r;
  49
  50         assert(f);
  51         assert(line);
  52
  53         if (ferror(f))
  54                 return -EIO;
  55
  56         needs_nl = !(flags & WRITE_STRING_FILE_AVOID_NEWLINE) && !endswith(line, "\n");
  57
  58         if (needs_nl && (flags & WRITE_STRING_FILE_DISABLE_BUFFER)) {
  59                 /* If STDIO buffering was disabled, then let's append the newline character to the string itself, so
  60                  * that the write goes out in one go, instead of two */
  61
  62                 line = strjoina(line, "\n");
  63                 needs_nl = false;
  64         }
  65
  66         if (fputs(line, f) == EOF)
  67                 return -errno;
  68
  69         if (needs_nl)
  70                 if (fputc('\n', f) == EOF)
  71                         return -errno;
  72
  73         if (flags & WRITE_STRING_FILE_SYNC)
  74                 r = fflush_sync_and_check(f);
  75         else
  76                 r = fflush_and_check(f);
  77         if (r < 0)
  78                 return r;
  79
  80         if (ts) {
  81                 struct timespec twice[2] = {*ts, *ts};
  82
  83                 if (futimens(fileno(f), twice) < 0)
  84                         return -errno;
  85         }
  86
  87         return 0;
  88 }
  89
  90 static int write_string_file_atomic(
  91                 const char *fn,
  92                 const char *line,
  93                 WriteStringFileFlags flags,
  94                 struct timespec *ts) {
  95
  96         _cleanup_fclose_ FILE *f = NULL;
  97         _cleanup_free_ char *p = NULL;
  98         int r;
  99
 100         assert(fn);
 101         assert(line);
 102
 103         r = fopen_temporary(fn, &f, &p);
 104         if (r < 0)
 105                 return r;
 106
 107         (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
 108         (void) fchmod_umask(fileno(f), 0644);
 109
 110         r = write_string_stream_ts(f, line, flags, ts);
 111         if (r < 0)
 112                 goto fail;
 113
 114         if (rename(p, fn) < 0) {
 115                 r = -errno;
 116                 goto fail;
 117         }
 118
 119         return 0;
 120
 121 fail:
 122         (void) unlink(p);
 123         return r;
 124 }
 125
 126 int write_string_file_ts(
 127                 const char *fn,
 128                 const char *line,
 129                 WriteStringFileFlags flags,
 130                 struct timespec *ts) {
 131
 132         _cleanup_fclose_ FILE *f = NULL;
 133         int q, r;
 134
 135         assert(fn);
 136         assert(line);
 137
 138         /* We don't know how to verify whether the file contents was already on-disk. */
 139         assert(!((flags & WRITE_STRING_FILE_VERIFY_ON_FAILURE) && (flags & WRITE_STRING_FILE_SYNC)));
 140
 141         if (flags & WRITE_STRING_FILE_ATOMIC) {
 142                 assert(flags & WRITE_STRING_FILE_CREATE);
 143
 144                 r = write_string_file_atomic(fn, line, flags, ts);
 145                 if (r < 0)
 146                         goto fail;
 147
 148                 return r;
 149         } else
 150                 assert(!ts);
 151
 152         if (flags & WRITE_STRING_FILE_CREATE) {
 153                 f = fopen(fn, "we");
 154                 if (!f) {
 155                         r = -errno;
 156                         goto fail;
 157                 }
 158         } else {
 159                 int fd;
 160
 161                 /* We manually build our own version of fopen(..., "we") that
 162                  * works without O_CREAT */
 163                 fd = open(fn, O_WRONLY|O_CLOEXEC|O_NOCTTY | ((flags & WRITE_STRING_FILE_NOFOLLOW) ? O_NOFOLLOW : 0));
 164                 if (fd < 0) {
 165                         r = -errno;
 166                         goto fail;
 167                 }
 168
 169                 f = fdopen(fd, "we");
 170                 if (!f) {
 171                         r = -errno;
 172                         safe_close(fd);
 173                         goto fail;
 174                 }
 175         }
 176
 177         (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
 178
 179         if (flags & WRITE_STRING_FILE_DISABLE_BUFFER)
 180                 setvbuf(f, NULL, _IONBF, 0);
 181
 182         r = write_string_stream_ts(f, line, flags, ts);
 183         if (r < 0)
 184                 goto fail;
 185
 186         return 0;
 187
 188 fail:
 189         if (!(flags & WRITE_STRING_FILE_VERIFY_ON_FAILURE))
 190                 return r;
 191
 192         f = safe_fclose(f);
 193
 194         /* OK, the operation failed, but let's see if the right
 195          * contents in place already. If so, eat up the error. */
 196
 197         q = verify_file(fn, line, !(flags & WRITE_STRING_FILE_AVOID_NEWLINE));
 198         if (q <= 0)
 199                 return r;
 200
 201         return 0;
 202 }
 203
 204 int write_string_filef(
 205                 const char *fn,
 206                 WriteStringFileFlags flags,
 207                 const char *format, ...) {
 208
 209         _cleanup_free_ char *p = NULL;
 210         va_list ap;
 211         int r;
 212
 213         va_start(ap, format);
 214         r = vasprintf(&p, format, ap);
 215         va_end(ap);
 216
 217         if (r < 0)
 218                 return -ENOMEM;
 219
 220         return write_string_file(fn, p, flags);
 221 }
 222
 223 int read_one_line_file(const char *fn, char **line) {
 224         _cleanup_fclose_ FILE *f = NULL;
 225         int r;
 226
 227         assert(fn);
 228         assert(line);
 229
 230         f = fopen(fn, "re");
 231         if (!f)
 232                 return -errno;
 233
 234         (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
 235
 236         r = read_line(f, LONG_LINE_MAX, line);
 237         return r < 0 ? r : 0;
 238 }
 239
 240 int verify_file(const char *fn, const char *blob, bool accept_extra_nl) {
 241         _cleanup_fclose_ FILE *f = NULL;
 242         _cleanup_free_ char *buf = NULL;
 243         size_t l, k;
 244
 245         assert(fn);
 246         assert(blob);
 247
 248         l = strlen(blob);
 249
 250         if (accept_extra_nl && endswith(blob, "\n"))
 251                 accept_extra_nl = false;
 252
 253         buf = malloc(l + accept_extra_nl + 1);
 254         if (!buf)
 255                 return -ENOMEM;
 256
 257         f = fopen(fn, "re");
 258         if (!f)
 259                 return -errno;
 260
 261         (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
 262
 263         /* We try to read one byte more than we need, so that we know whether we hit eof */
 264         errno = 0;
 265         k = fread(buf, 1, l + accept_extra_nl + 1, f);
 266         if (ferror(f))
 267                 return errno > 0 ? -errno : -EIO;
 268
 269         if (k != l && k != l + accept_extra_nl)
 270                 return 0;
 271         if (memcmp(buf, blob, l) != 0)
 272                 return 0;
 273         if (k > l && buf[l] != '\n')
 274                 return 0;
 275
 276         return 1;
 277 }
 278
 279 int read_full_stream(FILE *f, char **contents, size_t *size) {
 280         _cleanup_free_ char *buf = NULL;
 281         struct stat st;
 282         size_t n, l;
 283         int fd;
 284
 285         assert(f);
 286         assert(contents);
 287
 288         n = LINE_MAX;
 289
 290         fd = fileno(f);
 291         if (fd >= 0) { /* If the FILE* object is backed by an fd (as opposed to memory or such, see fmemopen(), let's
 292                         * optimize our buffering) */
 293
 294                 if (fstat(fileno(f), &st) < 0)
 295                         return -errno;
 296
 297                 if (S_ISREG(st.st_mode)) {
 298
 299                         /* Safety check */
 300                         if (st.st_size > READ_FULL_BYTES_MAX)
 301                                 return -E2BIG;
 302
 303                         /* Start with the right file size, but be prepared for files from /proc which generally report a file
 304                          * size of 0. Note that we increase the size to read here by one, so that the first read attempt
 305                          * already makes us notice the EOF. */
 306                         if (st.st_size > 0)
 307                                 n = st.st_size + 1;
 308                 }
 309         }
 310
 311         l = 0;
 312         for (;;) {
 313                 char *t;
 314                 size_t k;
 315
 316                 t = realloc(buf, n + 1);
 317                 if (!t)
 318                         return -ENOMEM;
 319
 320                 buf = t;
 321                 errno = 0;
 322                 k = fread(buf + l, 1, n - l, f);
 323                 if (k > 0)
 324                         l += k;
 325
 326                 if (ferror(f))
 327                         return errno > 0 ? -errno : -EIO;
 328
 329                 if (feof(f))
 330                         break;
 331
 332                 /* We aren't expecting fread() to return a short read outside
 333                  * of (error && eof), assert buffer is full and enlarge buffer.
 334                  */
 335                 assert(l == n);
 336
 337                 /* Safety check */
 338                 if (n >= READ_FULL_BYTES_MAX)
 339                         return -E2BIG;
 340
 341                 n = MIN(n * 2, READ_FULL_BYTES_MAX);
 342         }
 343
 344         buf[l] = 0;
 345         *contents = TAKE_PTR(buf);
 346
 347         if (size)
 348                 *size = l;
 349
 350         return 0;
 351 }
 352
 353 int read_full_file(const char *fn, char **contents, size_t *size) {
 354         _cleanup_fclose_ FILE *f = NULL;
 355
 356         assert(fn);
 357         assert(contents);
 358
 359         f = fopen(fn, "re");
 360         if (!f)
 361                 return -errno;
 362
 363         (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
 364
 365         return read_full_stream(f, contents, size);
 366 }
 367
 368 static int parse_env_file_internal(
 369                 FILE *f,
 370                 const char *fname,
 371                 const char *newline,
 372                 int (*push) (const char *filename, unsigned line,
 373                              const char *key, char *value, void *userdata, int *n_pushed),
 374                 void *userdata,
 375                 int *n_pushed) {
 376
 377         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;
 378         _cleanup_free_ char *contents = NULL, *key = NULL, *value = NULL;
 379         unsigned line = 1;
 380         char *p;
 381         int r;
 382
 383         enum {
 384                 PRE_KEY,
 385                 KEY,
 386                 PRE_VALUE,
 387                 VALUE,
 388                 VALUE_ESCAPE,
 389                 SINGLE_QUOTE_VALUE,
 390                 SINGLE_QUOTE_VALUE_ESCAPE,
 391                 DOUBLE_QUOTE_VALUE,
 392                 DOUBLE_QUOTE_VALUE_ESCAPE,
 393                 COMMENT,
 394                 COMMENT_ESCAPE
 395         } state = PRE_KEY;
 396
 397         assert(newline);
 398
 399         if (f)
 400                 r = read_full_stream(f, &contents, NULL);
 401         else
 402                 r = read_full_file(fname, &contents, NULL);
 403         if (r < 0)
 404                 return r;
 405
 406         for (p = contents; *p; p++) {
 407                 char c = *p;
 408
 409                 switch (state) {
 410
 411                 case PRE_KEY:
 412                         if (strchr(COMMENTS, c))
 413                                 state = COMMENT;
 414                         else if (!strchr(WHITESPACE, c)) {
 415                                 state = KEY;
 416                                 last_key_whitespace = (size_t) -1;
 417
 418                                 if (!GREEDY_REALLOC(key, key_alloc, n_key+2))
 419                                         return -ENOMEM;
 420
 421                                 key[n_key++] = c;
 422                         }
 423                         break;
 424
 425                 case KEY:
 426                         if (strchr(newline, c)) {
 427                                 state = PRE_KEY;
 428                                 line++;
 429                                 n_key = 0;
 430                         } else if (c == '=') {
 431                                 state = PRE_VALUE;
 432                                 last_value_whitespace = (size_t) -1;
 433                         } else {
 434                                 if (!strchr(WHITESPACE, c))
 435                                         last_key_whitespace = (size_t) -1;
 436                                 else if (last_key_whitespace == (size_t) -1)
 437                                          last_key_whitespace = n_key;
 438
 439                                 if (!GREEDY_REALLOC(key, key_alloc, n_key+2))
 440                                         return -ENOMEM;
 441
 442                                 key[n_key++] = c;
 443                         }
 444
 445                         break;
 446
 447                 case PRE_VALUE:
 448                         if (strchr(newline, c)) {
 449                                 state = PRE_KEY;
 450                                 line++;
 451                                 key[n_key] = 0;
 452
 453                                 if (value)
 454                                         value[n_value] = 0;
 455
 456                                 /* strip trailing whitespace from key */
 457                                 if (last_key_whitespace != (size_t) -1)
 458                                         key[last_key_whitespace] = 0;
 459
 460                                 r = push(fname, line, key, value, userdata, n_pushed);
 461                                 if (r < 0)
 462                                         return r;
 463
 464                                 n_key = 0;
 465                                 value = NULL;
 466                                 value_alloc = n_value = 0;
 467
 468                         } else if (c == '\'')
 469                                 state = SINGLE_QUOTE_VALUE;
 470                         else if (c == '\"')
 471                                 state = DOUBLE_QUOTE_VALUE;
 472                         else if (c == '\\')
 473                                 state = VALUE_ESCAPE;
 474                         else if (!strchr(WHITESPACE, c)) {
 475                                 state = VALUE;
 476
 477                                 if (!GREEDY_REALLOC(value, value_alloc, n_value+2))
 478                                         return  -ENOMEM;
 479
 480                                 value[n_value++] = c;
 481                         }
 482
 483                         break;
 484
 485                 case VALUE:
 486                         if (strchr(newline, c)) {
 487                                 state = PRE_KEY;
 488                                 line++;
 489
 490                                 key[n_key] = 0;
 491
 492                                 if (value)
 493                                         value[n_value] = 0;
 494
 495                                 /* Chomp off trailing whitespace from value */
 496                                 if (last_value_whitespace != (size_t) -1)
 497                                         value[last_value_whitespace] = 0;
 498
 499                                 /* strip trailing whitespace from key */
 500                                 if (last_key_whitespace != (size_t) -1)
 501                                         key[last_key_whitespace] = 0;
 502
 503                                 r = push(fname, line, key, value, userdata, n_pushed);
 504                                 if (r < 0)
 505                                         return r;
 506
 507                                 n_key = 0;
 508                                 value = NULL;
 509                                 value_alloc = n_value = 0;
 510
 511                         } else if (c == '\\') {
 512                                 state = VALUE_ESCAPE;
 513                                 last_value_whitespace = (size_t) -1;
 514                         } else {
 515                                 if (!strchr(WHITESPACE, c))
 516                                         last_value_whitespace = (size_t) -1;
 517                                 else if (last_value_whitespace == (size_t) -1)
 518                                         last_value_whitespace = n_value;
 519
 520                                 if (!GREEDY_REALLOC(value, value_alloc, n_value+2))
 521                                         return -ENOMEM;
 522
 523                                 value[n_value++] = c;
 524                         }
 525
 526                         break;
 527
 528                 case VALUE_ESCAPE:
 529                         state = VALUE;
 530
 531                         if (!strchr(newline, c)) {
 532                                 /* Escaped newlines we eat up entirely */
 533                                 if (!GREEDY_REALLOC(value, value_alloc, n_value+2))
 534                                         return -ENOMEM;
 535
 536                                 value[n_value++] = c;
 537                         }
 538                         break;
 539
 540                 case SINGLE_QUOTE_VALUE:
 541                         if (c == '\'')
 542                                 state = PRE_VALUE;
 543                         else if (c == '\\')
 544                                 state = SINGLE_QUOTE_VALUE_ESCAPE;
 545                         else {
 546                                 if (!GREEDY_REALLOC(value, value_alloc, n_value+2))
 547                                         return -ENOMEM;
 548
 549                                 value[n_value++] = c;
 550                         }
 551
 552                         break;
 553
 554                 case SINGLE_QUOTE_VALUE_ESCAPE:
 555                         state = SINGLE_QUOTE_VALUE;
 556
 557                         if (!strchr(newline, c)) {
 558                                 if (!GREEDY_REALLOC(value, value_alloc, n_value+2))
 559                                         return -ENOMEM;
 560
 561                                 value[n_value++] = c;
 562                         }
 563                         break;
 564
 565                 case DOUBLE_QUOTE_VALUE:
 566                         if (c == '\"')
 567                                 state = PRE_VALUE;
 568                         else if (c == '\\')
 569                                 state = DOUBLE_QUOTE_VALUE_ESCAPE;
 570                         else {
 571                                 if (!GREEDY_REALLOC(value, value_alloc, n_value+2))
 572                                         return -ENOMEM;
 573
 574                                 value[n_value++] = c;
 575                         }
 576
 577                         break;
 578
 579                 case DOUBLE_QUOTE_VALUE_ESCAPE:
 580                         state = DOUBLE_QUOTE_VALUE;
 581
 582                         if (!strchr(newline, c)) {
 583                                 if (!GREEDY_REALLOC(value, value_alloc, n_value+2))
 584                                         return -ENOMEM;
 585
 586                                 value[n_value++] = c;
 587                         }
 588                         break;
 589
 590                 case COMMENT:
 591                         if (c == '\\')
 592                                 state = COMMENT_ESCAPE;
 593                         else if (strchr(newline, c)) {
 594                                 state = PRE_KEY;
 595                                 line++;
 596                         }
 597                         break;
 598
 599                 case COMMENT_ESCAPE:
 600                         state = COMMENT;
 601                         break;
 602                 }
 603         }
 604
 605         if (IN_SET(state,
 606                    PRE_VALUE,
 607                    VALUE,
 608                    VALUE_ESCAPE,
 609                    SINGLE_QUOTE_VALUE,
 610                    SINGLE_QUOTE_VALUE_ESCAPE,
 611                    DOUBLE_QUOTE_VALUE,
 612                    DOUBLE_QUOTE_VALUE_ESCAPE)) {
 613
 614                 key[n_key] = 0;
 615
 616                 if (value)
 617                         value[n_value] = 0;
 618
 619                 if (state == VALUE)
 620                         if (last_value_whitespace != (size_t) -1)
 621                                 value[last_value_whitespace] = 0;
 622
 623                 /* strip trailing whitespace from key */
 624                 if (last_key_whitespace != (size_t) -1)
 625                         key[last_key_whitespace] = 0;
 626
 627                 r = push(fname, line, key, value, userdata, n_pushed);
 628                 if (r < 0)
 629                         return r;
 630
 631                 value = NULL;
 632         }
 633
 634         return 0;
 635 }
 636
 637 static int check_utf8ness_and_warn(
 638                 const char *filename, unsigned line,
 639                 const char *key, char *value) {
 640
 641         if (!utf8_is_valid(key)) {
 642                 _cleanup_free_ char *p = NULL;
 643
 644                 p = utf8_escape_invalid(key);
 645                 log_error("%s:%u: invalid UTF-8 in key '%s', ignoring.", strna(filename), line, p);
 646                 return -EINVAL;
 647         }
 648
 649         if (value && !utf8_is_valid(value)) {
 650                 _cleanup_free_ char *p = NULL;
 651
 652                 p = utf8_escape_invalid(value);
 653                 log_error("%s:%u: invalid UTF-8 value for key %s: '%s', ignoring.", strna(filename), line, key, p);
 654                 return -EINVAL;
 655         }
 656
 657         return 0;
 658 }
 659
 660 static int parse_env_file_push(
 661                 const char *filename, unsigned line,
 662                 const char *key, char *value,
 663                 void *userdata,
 664                 int *n_pushed) {
 665
 666         const char *k;
 667         va_list aq, *ap = userdata;
 668         int r;
 669
 670         r = check_utf8ness_and_warn(filename, line, key, value);
 671         if (r < 0)
 672                 return r;
 673
 674         va_copy(aq, *ap);
 675
 676         while ((k = va_arg(aq, const char *))) {
 677                 char **v;
 678
 679                 v = va_arg(aq, char **);
 680
 681                 if (streq(key, k)) {
 682                         va_end(aq);
 683                         free(*v);
 684                         *v = value;
 685
 686                         if (n_pushed)
 687                                 (*n_pushed)++;
 688
 689                         return 1;
 690                 }
 691         }
 692
 693         va_end(aq);
 694         free(value);
 695
 696         return 0;
 697 }
 698
 699 int parse_env_filev(
 700                 FILE *f,
 701                 const char *fname,
 702                 const char *newline,
 703                 va_list ap) {
 704
 705         int r, n_pushed = 0;
 706         va_list aq;
 707
 708         if (!newline)
 709                 newline = NEWLINE;
 710
 711         va_copy(aq, ap);
 712         r = parse_env_file_internal(f, fname, newline, parse_env_file_push, &aq, &n_pushed);
 713         va_end(aq);
 714         if (r < 0)
 715                 return r;
 716
 717         return n_pushed;
 718 }
 719
 720 int parse_env_file(
 721                 FILE *f,
 722                 const char *fname,
 723                 const char *newline,
 724                 ...) {
 725
 726         va_list ap;
 727         int r;
 728
 729         va_start(ap, newline);
 730         r = parse_env_filev(f, fname, newline, ap);
 731         va_end(ap);
 732
 733         return r;
 734 }
 735
 736 static int load_env_file_push(
 737                 const char *filename, unsigned line,
 738                 const char *key, char *value,
 739                 void *userdata,
 740                 int *n_pushed) {
 741         char ***m = userdata;
 742         char *p;
 743         int r;
 744
 745         r = check_utf8ness_and_warn(filename, line, key, value);
 746         if (r < 0)
 747                 return r;
 748
 749         p = strjoin(key, "=", value);
 750         if (!p)
 751                 return -ENOMEM;
 752
 753         r = strv_env_replace(m, p);
 754         if (r < 0) {
 755                 free(p);
 756                 return r;
 757         }
 758
 759         if (n_pushed)
 760                 (*n_pushed)++;
 761
 762         free(value);
 763         return 0;
 764 }
 765
 766 int load_env_file(FILE *f, const char *fname, const char *newline, char ***rl) {
 767         char **m = NULL;
 768         int r;
 769
 770         if (!newline)
 771                 newline = NEWLINE;
 772
 773         r = parse_env_file_internal(f, fname, newline, load_env_file_push, &m, NULL);
 774         if (r < 0) {
 775                 strv_free(m);
 776                 return r;
 777         }
 778
 779         *rl = m;
 780         return 0;
 781 }
 782
 783 static int load_env_file_push_pairs(
 784                 const char *filename, unsigned line,
 785                 const char *key, char *value,
 786                 void *userdata,
 787                 int *n_pushed) {
 788         char ***m = userdata;
 789         int r;
 790
 791         r = check_utf8ness_and_warn(filename, line, key, value);
 792         if (r < 0)
 793                 return r;
 794
 795         r = strv_extend(m, key);
 796         if (r < 0)
 797                 return -ENOMEM;
 798
 799         if (!value) {
 800                 r = strv_extend(m, "");
 801                 if (r < 0)
 802                         return -ENOMEM;
 803         } else {
 804                 r = strv_push(m, value);
 805                 if (r < 0)
 806                         return r;
 807         }
 808
 809         if (n_pushed)
 810                 (*n_pushed)++;
 811
 812         return 0;
 813 }
 814
 815 int load_env_file_pairs(FILE *f, const char *fname, const char *newline, char ***rl) {
 816         char **m = NULL;
 817         int r;
 818
 819         if (!newline)
 820                 newline = NEWLINE;
 821
 822         r = parse_env_file_internal(f, fname, newline, load_env_file_push_pairs, &m, NULL);
 823         if (r < 0) {
 824                 strv_free(m);
 825                 return r;
 826         }
 827
 828         *rl = m;
 829         return 0;
 830 }
 831
 832 static int merge_env_file_push(
 833                 const char *filename, unsigned line,
 834                 const char *key, char *value,
 835                 void *userdata,
 836                 int *n_pushed) {
 837
 838         char ***env = userdata;
 839         char *expanded_value;
 840
 841         assert(env);
 842
 843         if (!value) {
 844                 log_error("%s:%u: invalid syntax (around \"%s\"), ignoring.", strna(filename), line, key);
 845                 return 0;
 846         }
 847
 848         if (!env_name_is_valid(key)) {
 849                 log_error("%s:%u: invalid variable name \"%s\", ignoring.", strna(filename), line, key);
 850                 free(value);
 851                 return 0;
 852         }
 853
 854         expanded_value = replace_env(value, *env,
 855                                      REPLACE_ENV_USE_ENVIRONMENT|
 856                                      REPLACE_ENV_ALLOW_BRACELESS|
 857                                      REPLACE_ENV_ALLOW_EXTENDED);
 858         if (!expanded_value)
 859                 return -ENOMEM;
 860
 861         free_and_replace(value, expanded_value);
 862
 863         return load_env_file_push(filename, line, key, value, env, n_pushed);
 864 }
 865
 866 int merge_env_file(
 867                 char ***env,
 868                 FILE *f,
 869                 const char *fname) {
 870
 871         /* NOTE: this function supports braceful and braceless variable expansions,
 872          * plus "extended" substitutions, unlike other exported parsing functions.
 873          */
 874
 875         return parse_env_file_internal(f, fname, NEWLINE, merge_env_file_push, env, NULL);
 876 }
 877
 878 static void write_env_var(FILE *f, const char *v) {
 879         const char *p;
 880
 881         p = strchr(v, '=');
 882         if (!p) {
 883                 /* Fallback */
 884                 fputs_unlocked(v, f);
 885                 fputc_unlocked('\n', f);
 886                 return;
 887         }
 888
 889         p++;
 890         fwrite_unlocked(v, 1, p-v, f);
 891
 892         if (string_has_cc(p, NULL) || chars_intersect(p, WHITESPACE SHELL_NEED_QUOTES)) {
 893                 fputc_unlocked('\"', f);
 894
 895                 for (; *p; p++) {
 896                         if (strchr(SHELL_NEED_ESCAPE, *p))
 897                                 fputc_unlocked('\\', f);
 898
 899                         fputc_unlocked(*p, f);
 900                 }
 901
 902                 fputc_unlocked('\"', f);
 903         } else
 904                 fputs_unlocked(p, f);
 905
 906         fputc_unlocked('\n', f);
 907 }
 908
 909 int write_env_file(const char *fname, char **l) {
 910         _cleanup_fclose_ FILE *f = NULL;
 911         _cleanup_free_ char *p = NULL;
 912         char **i;
 913         int r;
 914
 915         assert(fname);
 916
 917         r = fopen_temporary(fname, &f, &p);
 918         if (r < 0)
 919                 return r;
 920
 921         (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
 922         (void) fchmod_umask(fileno(f), 0644);
 923
 924         STRV_FOREACH(i, l)
 925                 write_env_var(f, *i);
 926
 927         r = fflush_and_check(f);
 928         if (r >= 0) {
 929                 if (rename(p, fname) >= 0)
 930                         return 0;
 931
 932                 r = -errno;
 933         }
 934
 935         unlink(p);
 936         return r;
 937 }
 938
 939 int executable_is_script(const char *path, char **interpreter) {
 940         _cleanup_free_ char *line = NULL;
 941         size_t len;
 942         char *ans;
 943         int r;
 944
 945         assert(path);
 946
 947         r = read_one_line_file(path, &line);
 948         if (r == -ENOBUFS) /* First line overly long? if so, then it's not a script */
 949                 return 0;
 950         if (r < 0)
 951                 return r;
 952
 953         if (!startswith(line, "#!"))
 954                 return 0;
 955
 956         ans = strstrip(line + 2);
 957         len = strcspn(ans, " \t");
 958
 959         if (len == 0)
 960                 return 0;
 961
 962         ans = strndup(ans, len);
 963         if (!ans)
 964                 return -ENOMEM;
 965
 966         *interpreter = ans;
 967         return 1;
 968 }
 969
 970 /**
 971  * Retrieve one field from a file like /proc/self/status.  pattern
 972  * should not include whitespace or the delimiter (':'). pattern matches only
 973  * the beginning of a line. Whitespace before ':' is skipped. Whitespace and
 974  * zeros after the ':' will be skipped. field must be freed afterwards.
 975  * terminator specifies the terminating characters of the field value (not
 976  * included in the value).
 977  */
 978 int get_proc_field(const char *filename, const char *pattern, const char *terminator, char **field) {
 979         _cleanup_free_ char *status = NULL;
 980         char *t, *f;
 981         size_t len;
 982         int r;
 983
 984         assert(terminator);
 985         assert(filename);
 986         assert(pattern);
 987         assert(field);
 988
 989         r = read_full_file(filename, &status, NULL);
 990         if (r < 0)
 991                 return r;
 992
 993         t = status;
 994
 995         do {
 996                 bool pattern_ok;
 997
 998                 do {
 999                         t = strstr(t, pattern);
1000                         if (!t)
1001                                 return -ENOENT;
1002
1003                         /* Check that pattern occurs in beginning of line. */
1004                         pattern_ok = (t == status || t[-1] == '\n');
1005
1006                         t += strlen(pattern);
1007
1008                 } while (!pattern_ok);
1009
1010                 t += strspn(t, " \t");
1011                 if (!*t)
1012                         return -ENOENT;
1013
1014         } while (*t != ':');
1015
1016         t++;
1017
1018         if (*t) {
1019                 t += strspn(t, " \t");
1020
1021                 /* Also skip zeros, because when this is used for
1022                  * capabilities, we don't want the zeros. This way the
1023                  * same capability set always maps to the same string,
1024                  * irrespective of the total capability set size. For
1025                  * other numbers it shouldn't matter. */
1026                 t += strspn(t, "0");
1027                 /* Back off one char if there's nothing but whitespace
1028                    and zeros */
1029                 if (!*t || isspace(*t))
1030                         t--;
1031         }
1032
1033         len = strcspn(t, terminator);
1034
1035         f = strndup(t, len);
1036         if (!f)
1037                 return -ENOMEM;
1038
1039         *field = f;
1040         return 0;
1041 }
1042
1043 DIR *xopendirat(int fd, const char *name, int flags) {
1044         int nfd;
1045         DIR *d;
1046
1047         assert(!(flags & O_CREAT));
1048
1049         nfd = openat(fd, name, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|flags, 0);
1050         if (nfd < 0)
1051                 return NULL;
1052
1053         d = fdopendir(nfd);
1054         if (!d) {
1055                 safe_close(nfd);
1056                 return NULL;
1057         }
1058
1059         return d;
1060 }
1061
1062 static int search_and_fopen_internal(const char *path, const char *mode, const char *root, char **search, FILE **_f) {
1063         char **i;
1064
1065         assert(path);
1066         assert(mode);
1067         assert(_f);
1068
1069         if (!path_strv_resolve_uniq(search, root))
1070                 return -ENOMEM;
1071
1072         STRV_FOREACH(i, search) {
1073                 _cleanup_free_ char *p = NULL;
1074                 FILE *f;
1075
1076                 if (root)
1077                         p = strjoin(root, *i, "/", path);
1078                 else
1079                         p = strjoin(*i, "/", path);
1080                 if (!p)
1081                         return -ENOMEM;
1082
1083                 f = fopen(p, mode);
1084                 if (f) {
1085                         *_f = f;
1086                         return 0;
1087                 }
1088
1089                 if (errno != ENOENT)
1090                         return -errno;
1091         }
1092
1093         return -ENOENT;
1094 }
1095
1096 int search_and_fopen(const char *path, const char *mode, const char *root, const char **search, FILE **_f) {
1097         _cleanup_strv_free_ char **copy = NULL;
1098
1099         assert(path);
1100         assert(mode);
1101         assert(_f);
1102
1103         if (path_is_absolute(path)) {
1104                 FILE *f;
1105
1106                 f = fopen(path, mode);
1107                 if (f) {
1108                         *_f = f;
1109                         return 0;
1110                 }
1111
1112                 return -errno;
1113         }
1114
1115         copy = strv_copy((char**) search);
1116         if (!copy)
1117                 return -ENOMEM;
1118
1119         return search_and_fopen_internal(path, mode, root, copy, _f);
1120 }
1121
1122 int search_and_fopen_nulstr(const char *path, const char *mode, const char *root, const char *search, FILE **_f) {
1123         _cleanup_strv_free_ char **s = NULL;
1124
1125         if (path_is_absolute(path)) {
1126                 FILE *f;
1127
1128                 f = fopen(path, mode);
1129                 if (f) {
1130                         *_f = f;
1131                         return 0;
1132                 }
1133
1134                 return -errno;
1135         }
1136
1137         s = strv_split_nulstr(search);
1138         if (!s)
1139                 return -ENOMEM;
1140
1141         return search_and_fopen_internal(path, mode, root, s, _f);
1142 }
1143
1144 int fopen_temporary(const char *path, FILE **_f, char **_temp_path) {
1145         FILE *f;
1146         char *t;
1147         int r, fd;
1148
1149         assert(path);
1150         assert(_f);
1151         assert(_temp_path);
1152
1153         r = tempfn_xxxxxx(path, NULL, &t);
1154         if (r < 0)
1155                 return r;
1156
1157         fd = mkostemp_safe(t);
1158         if (fd < 0) {
1159                 free(t);
1160                 return -errno;
1161         }
1162
1163         f = fdopen(fd, "we");
1164         if (!f) {
1165                 unlink_noerrno(t);
1166                 free(t);
1167                 safe_close(fd);
1168                 return -errno;
1169         }
1170
1171         *_f = f;
1172         *_temp_path = t;
1173
1174         return 0;
1175 }
1176
1177 int fflush_and_check(FILE *f) {
1178         assert(f);
1179
1180         errno = 0;
1181         fflush(f);
1182
1183         if (ferror(f))
1184                 return errno > 0 ? -errno : -EIO;
1185
1186         return 0;
1187 }
1188
1189 int fflush_sync_and_check(FILE *f) {
1190         int r;
1191
1192         assert(f);
1193
1194         r = fflush_and_check(f);
1195         if (r < 0)
1196                 return r;
1197
1198         if (fsync(fileno(f)) < 0)
1199                 return -errno;
1200
1201         r = fsync_directory_of_file(fileno(f));
1202         if (r < 0)
1203                 return r;
1204
1205         return 0;
1206 }
1207
1208 /* This is much like mkostemp() but is subject to umask(). */
1209 int mkostemp_safe(char *pattern) {
1210         _cleanup_umask_ mode_t u = 0;
1211         int fd;
1212
1213         assert(pattern);
1214
1215         u = umask(077);
1216
1217         fd = mkostemp(pattern, O_CLOEXEC);
1218         if (fd < 0)
1219                 return -errno;
1220
1221         return fd;
1222 }
1223
1224 int fmkostemp_safe(char *pattern, const char *mode, FILE **ret_f) {
1225         int fd;
1226         FILE *f;
1227
1228         fd = mkostemp_safe(pattern);
1229         if (fd < 0)
1230                 return fd;
1231
1232         f = fdopen(fd, mode);
1233         if (!f) {
1234                 safe_close(fd);
1235                 return -errno;
1236         }
1237
1238         *ret_f = f;
1239         return 0;
1240 }
1241
1242 int tempfn_xxxxxx(const char *p, const char *extra, char **ret) {
1243         const char *fn;
1244         char *t;
1245
1246         assert(ret);
1247
1248         if (isempty(p))
1249                 return -EINVAL;
1250         if (path_equal(p, "/"))
1251                 return -EINVAL;
1252
1253         /*
1254          * Turns this:
1255          *         /foo/bar/waldo
1256          *
1257          * Into this:
1258          *         /foo/bar/.#<extra>waldoXXXXXX
1259          */
1260
1261         fn = basename(p);
1262         if (!filename_is_valid(fn))
1263                 return -EINVAL;
1264
1265         extra = strempty(extra);
1266
1267         t = new(char, strlen(p) + 2 + strlen(extra) + 6 + 1);
1268         if (!t)
1269                 return -ENOMEM;
1270
1271         strcpy(stpcpy(stpcpy(stpcpy(mempcpy(t, p, fn - p), ".#"), extra), fn), "XXXXXX");
1272
1273         *ret = path_simplify(t, false);
1274         return 0;
1275 }
1276
1277 int tempfn_random(const char *p, const char *extra, char **ret) {
1278         const char *fn;
1279         char *t, *x;
1280         uint64_t u;
1281         unsigned i;
1282
1283         assert(ret);
1284
1285         if (isempty(p))
1286                 return -EINVAL;
1287         if (path_equal(p, "/"))
1288                 return -EINVAL;
1289
1290         /*
1291          * Turns this:
1292          *         /foo/bar/waldo
1293          *
1294          * Into this:
1295          *         /foo/bar/.#<extra>waldobaa2a261115984a9
1296          */
1297
1298         fn = basename(p);
1299         if (!filename_is_valid(fn))
1300                 return -EINVAL;
1301
1302         extra = strempty(extra);
1303
1304         t = new(char, strlen(p) + 2 + strlen(extra) + 16 + 1);
1305         if (!t)
1306                 return -ENOMEM;
1307
1308         x = stpcpy(stpcpy(stpcpy(mempcpy(t, p, fn - p), ".#"), extra), fn);
1309
1310         u = random_u64();
1311         for (i = 0; i < 16; i++) {
1312                 *(x++) = hexchar(u & 0xF);
1313                 u >>= 4;
1314         }
1315
1316         *x = 0;
1317
1318         *ret = path_simplify(t, false);
1319         return 0;
1320 }
1321
1322 int tempfn_random_child(const char *p, const char *extra, char **ret) {
1323         char *t, *x;
1324         uint64_t u;
1325         unsigned i;
1326         int r;
1327
1328         assert(ret);
1329
1330         /* Turns this:
1331          *         /foo/bar/waldo
1332          * Into this:
1333          *         /foo/bar/waldo/.#<extra>3c2b6219aa75d7d0
1334          */
1335
1336         if (!p) {
1337                 r = tmp_dir(&p);
1338                 if (r < 0)
1339                         return r;
1340         }
1341
1342         extra = strempty(extra);
1343
1344         t = new(char, strlen(p) + 3 + strlen(extra) + 16 + 1);
1345         if (!t)
1346                 return -ENOMEM;
1347
1348         if (isempty(p))
1349                 x = stpcpy(stpcpy(t, ".#"), extra);
1350         else
1351                 x = stpcpy(stpcpy(stpcpy(t, p), "/.#"), extra);
1352
1353         u = random_u64();
1354         for (i = 0; i < 16; i++) {
1355                 *(x++) = hexchar(u & 0xF);
1356                 u >>= 4;
1357         }
1358
1359         *x = 0;
1360
1361         *ret = path_simplify(t, false);
1362         return 0;
1363 }
1364
1365 int write_timestamp_file_atomic(const char *fn, usec_t n) {
1366         char ln[DECIMAL_STR_MAX(n)+2];
1367
1368         /* Creates a "timestamp" file, that contains nothing but a
1369          * usec_t timestamp, formatted in ASCII. */
1370
1371         if (n <= 0 || n >= USEC_INFINITY)
1372                 return -ERANGE;
1373
1374         xsprintf(ln, USEC_FMT "\n", n);
1375
1376         return write_string_file(fn, ln, WRITE_STRING_FILE_CREATE|WRITE_STRING_FILE_ATOMIC);
1377 }
1378
1379 int read_timestamp_file(const char *fn, usec_t *ret) {
1380         _cleanup_free_ char *ln = NULL;
1381         uint64_t t;
1382         int r;
1383
1384         r = read_one_line_file(fn, &ln);
1385         if (r < 0)
1386                 return r;
1387
1388         r = safe_atou64(ln, &t);
1389         if (r < 0)
1390                 return r;
1391
1392         if (t <= 0 || t >= (uint64_t) USEC_INFINITY)
1393                 return -ERANGE;
1394
1395         *ret = (usec_t) t;
1396         return 0;
1397 }
1398
1399 int fputs_with_space(FILE *f, const char *s, const char *separator, bool *space) {
1400         int r;
1401
1402         assert(s);
1403
1404         /* Outputs the specified string with fputs(), but optionally prefixes it with a separator. The *space parameter
1405          * when specified shall initially point to a boolean variable initialized to false. It is set to true after the
1406          * first invocation. This call is supposed to be use in loops, where a separator shall be inserted between each
1407          * element, but not before the first one. */
1408
1409         if (!f)
1410                 f = stdout;
1411
1412         if (space) {
1413                 if (!separator)
1414                         separator = " ";
1415
1416                 if (*space) {
1417                         r = fputs(separator, f);
1418                         if (r < 0)
1419                                 return r;
1420                 }
1421
1422                 *space = true;
1423         }
1424
1425         return fputs(s, f);
1426 }
1427
1428 int open_tmpfile_unlinkable(const char *directory, int flags) {
1429         char *p;
1430         int fd, r;
1431
1432         if (!directory) {
1433                 r = tmp_dir(&directory);
1434                 if (r < 0)
1435                         return r;
1436         } else if (isempty(directory))
1437                 return -EINVAL;
1438
1439         /* Returns an unlinked temporary file that cannot be linked into the file system anymore */
1440
1441         /* Try O_TMPFILE first, if it is supported */
1442         fd = open(directory, flags|O_TMPFILE|O_EXCL, S_IRUSR|S_IWUSR);
1443         if (fd >= 0)
1444                 return fd;
1445
1446         /* Fall back to unguessable name + unlinking */
1447         p = strjoina(directory, "/systemd-tmp-XXXXXX");
1448
1449         fd = mkostemp_safe(p);
1450         if (fd < 0)
1451                 return fd;
1452
1453         (void) unlink(p);
1454
1455         return fd;
1456 }
1457
1458 int open_tmpfile_linkable(const char *target, int flags, char **ret_path) {
1459         _cleanup_free_ char *tmp = NULL;
1460         int r, fd;
1461
1462         assert(target);
1463         assert(ret_path);
1464
1465         /* Don't allow O_EXCL, as that has a special meaning for O_TMPFILE */
1466         assert((flags & O_EXCL) == 0);
1467
1468         /* Creates a temporary file, that shall be renamed to "target" later. If possible, this uses O_TMPFILE – in
1469          * which case "ret_path" will be returned as NULL. If not possible a the tempoary path name used is returned in
1470          * "ret_path". Use link_tmpfile() below to rename the result after writing the file in full. */
1471
1472         fd = open_parent(target, O_TMPFILE|flags, 0640);
1473         if (fd >= 0) {
1474                 *ret_path = NULL;
1475                 return fd;
1476         }
1477
1478         log_debug_errno(fd, "Failed to use O_TMPFILE for %s: %m", target);
1479
1480         r = tempfn_random(target, NULL, &tmp);
1481         if (r < 0)
1482                 return r;
1483
1484         fd = open(tmp, O_CREAT|O_EXCL|O_NOFOLLOW|O_NOCTTY|flags, 0640);
1485         if (fd < 0)
1486                 return -errno;
1487
1488         *ret_path = TAKE_PTR(tmp);
1489
1490         return fd;
1491 }
1492
1493 int open_serialization_fd(const char *ident) {
1494         int fd = -1;
1495
1496         fd = memfd_create(ident, MFD_CLOEXEC);
1497         if (fd < 0) {
1498                 const char *path;
1499
1500                 path = getpid_cached() == 1 ? "/run/systemd" : "/tmp";
1501                 fd = open_tmpfile_unlinkable(path, O_RDWR|O_CLOEXEC);
1502                 if (fd < 0)
1503                         return fd;
1504
1505                 log_debug("Serializing %s to %s.", ident, path);
1506         } else
1507                 log_debug("Serializing %s to memfd.", ident);
1508
1509         return fd;
1510 }
1511
1512 int link_tmpfile(int fd, const char *path, const char *target) {
1513         int r;
1514
1515         assert(fd >= 0);
1516         assert(target);
1517
1518         /* Moves a temporary file created with open_tmpfile() above into its final place. if "path" is NULL an fd
1519          * created with O_TMPFILE is assumed, and linkat() is used. Otherwise it is assumed O_TMPFILE is not supported
1520          * on the directory, and renameat2() is used instead.
1521          *
1522          * Note that in both cases we will not replace existing files. This is because linkat() does not support this
1523          * operation currently (renameat2() does), and there is no nice way to emulate this. */
1524
1525         if (path) {
1526                 r = rename_noreplace(AT_FDCWD, path, AT_FDCWD, target);
1527                 if (r < 0)
1528                         return r;
1529         } else {
1530                 char proc_fd_path[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(fd) + 1];
1531
1532                 xsprintf(proc_fd_path, "/proc/self/fd/%i", fd);
1533
1534                 if (linkat(AT_FDCWD, proc_fd_path, AT_FDCWD, target, AT_SYMLINK_FOLLOW) < 0)
1535                         return -errno;
1536         }
1537
1538         return 0;
1539 }
1540
1541 int read_nul_string(FILE *f, char **ret) {
1542         _cleanup_free_ char *x = NULL;
1543         size_t allocated = 0, n = 0;
1544
1545         assert(f);
1546         assert(ret);
1547
1548         /* Reads a NUL-terminated string from the specified file. */
1549
1550         for (;;) {
1551                 int c;
1552
1553                 if (!GREEDY_REALLOC(x, allocated, n+2))
1554                         return -ENOMEM;
1555
1556                 c = fgetc(f);
1557                 if (c == 0) /* Terminate at NUL byte */
1558                         break;
1559                 if (c == EOF) {
1560                         if (ferror(f))
1561                                 return -errno;
1562                         break; /* Terminate at EOF */
1563                 }
1564
1565                 x[n++] = (char) c;
1566         }
1567
1568         if (x)
1569                 x[n] = 0;
1570         else {
1571                 x = new0(char, 1);
1572                 if (!x)
1573                         return -ENOMEM;
1574         }
1575
1576         *ret = TAKE_PTR(x);
1577
1578         return 0;
1579 }
1580
1581 int mkdtemp_malloc(const char *template, char **ret) {
1582         _cleanup_free_ char *p = NULL;
1583         int r;
1584
1585         assert(ret);
1586
1587         if (template)
1588                 p = strdup(template);
1589         else {
1590                 const char *tmp;
1591
1592                 r = tmp_dir(&tmp);
1593                 if (r < 0)
1594                         return r;
1595
1596                 p = strjoin(tmp, "/XXXXXX");
1597         }
1598         if (!p)
1599                 return -ENOMEM;
1600
1601         if (!mkdtemp(p))
1602                 return -errno;
1603
1604         *ret = TAKE_PTR(p);
1605         return 0;
1606 }
1607
1608 DEFINE_TRIVIAL_CLEANUP_FUNC(FILE*, funlockfile);
1609
1610 int read_line(FILE *f, size_t limit, char **ret) {
1611         _cleanup_free_ char *buffer = NULL;
1612         size_t n = 0, allocated = 0, count = 0;
1613
1614         assert(f);
1615
1616         /* Something like a bounded version of getline().
1617          *
1618          * Considers EOF, \n and \0 end of line delimiters, and does not include these delimiters in the string
1619          * returned.
1620          *
1621          * Returns the number of bytes read from the files (i.e. including delimiters — this hence usually differs from
1622          * the number of characters in the returned string). When EOF is hit, 0 is returned.
1623          *
1624          * The input parameter limit is the maximum numbers of characters in the returned string, i.e. excluding
1625          * delimiters. If the limit is hit we fail and return -ENOBUFS.
1626          *
1627          * If a line shall be skipped ret may be initialized as NULL. */
1628
1629         if (ret) {
1630                 if (!GREEDY_REALLOC(buffer, allocated, 1))
1631                         return -ENOMEM;
1632         }
1633
1634         {
1635                 _unused_ _cleanup_(funlockfilep) FILE *flocked = f;
1636                 flockfile(f);
1637
1638                 for (;;) {
1639                         int c;
1640
1641                         if (n >= limit)
1642                                 return -ENOBUFS;
1643
1644                         errno = 0;
1645                         c = fgetc_unlocked(f);
1646                         if (c == EOF) {
1647                                 /* if we read an error, and have no data to return, then propagate the error */
1648                                 if (ferror_unlocked(f) && n == 0)
1649                                         return errno > 0 ? -errno : -EIO;
1650
1651                                 break;
1652                         }
1653
1654                         count++;
1655
1656                         if (IN_SET(c, '\n', 0)) /* Reached a delimiter */
1657                                 break;
1658
1659                         if (ret) {
1660                                 if (!GREEDY_REALLOC(buffer, allocated, n + 2))
1661                                         return -ENOMEM;
1662
1663                                 buffer[n] = (char) c;
1664                         }
1665
1666                         n++;
1667                 }
1668         }
1669
1670         if (ret) {
1671                 buffer[n] = 0;
1672
1673                 *ret = TAKE_PTR(buffer);
1674         }
1675
1676         return (int) count;
1677 }