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