src/basic/fileio.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   This file is part of systemd.
   4
   5   Copyright 2010 Lennart Poettering
   6 ***/
   7
   8 #include <errno.h>
   9 #include <fcntl.h>
  10 #include <limits.h>
  11 #include <stdarg.h>
  12 #include <stdint.h>
  13 #include <stdio_ext.h>
  14 #include <stdlib.h>
  15 #include <string.h>
  16 #include <sys/mman.h>
  17 #include <sys/stat.h>
  18 #include <sys/types.h>
  19 #include <unistd.h>
  20
  21 #include "alloc-util.h"
  22 #include "ctype.h"
  23 #include "def.h"
  24 #include "env-util.h"
  25 #include "escape.h"
  26 #include "fd-util.h"
  27 #include "fileio.h"
  28 #include "fs-util.h"
  29 #include "hexdecoct.h"
  30 #include "log.h"
  31 #include "macro.h"
  32 #include "missing.h"
  33 #include "parse-util.h"
  34 #include "path-util.h"
  35 #include "process-util.h"
  36 #include "random-util.h"
  37 #include "stdio-util.h"
  38 #include "string-util.h"
  39 #include "strv.h"
  40 #include "time-util.h"
  41 #include "umask-util.h"
  42 #include "utf8.h"
  43
  44 #define READ_FULL_BYTES_MAX (4U*1024U*1024U)
  45
  46 int write_string_stream_ts(
  47                 FILE *f,
  48                 const char *line,
  49                 WriteStringFileFlags flags,
  50                 struct timespec *ts) {
  51
  52         bool needs_nl;
  53         int r;
  54
  55         assert(f);
  56         assert(line);
  57
  58         if (ferror(f))
  59                 return -EIO;
  60
  61         needs_nl = !(flags & WRITE_STRING_FILE_AVOID_NEWLINE) && !endswith(line, "\n");
  62
  63         if (needs_nl && (flags & WRITE_STRING_FILE_DISABLE_BUFFER)) {
  64                 /* If STDIO buffering was disabled, then let's append the newline character to the string itself, so
  65                  * that the write goes out in one go, instead of two */
  66
  67                 line = strjoina(line, "\n");
  68                 needs_nl = false;
  69         }
  70
  71         if (fputs(line, f) == EOF)
  72                 return -errno;
  73
  74         if (needs_nl)
  75                 if (fputc('\n', f) == EOF)
  76                         return -errno;
  77
  78         if (flags & WRITE_STRING_FILE_SYNC)
  79                 r = fflush_sync_and_check(f);
  80         else
  81                 r = fflush_and_check(f);
  82         if (r < 0)
  83                 return r;
  84
  85         if (ts) {
  86                 struct timespec twice[2] = {*ts, *ts};
  87
  88                 if (futimens(fileno(f), twice) < 0)
  89                         return -errno;
  90         }
  91
  92         return 0;
  93 }
  94
  95 static int write_string_file_atomic(
  96                 const char *fn,
  97                 const char *line,
  98                 WriteStringFileFlags flags,
  99                 struct timespec *ts) {
 100
 101         _cleanup_fclose_ FILE *f = NULL;
 102         _cleanup_free_ char *p = NULL;
 103         int r;
 104
 105         assert(fn);
 106         assert(line);
 107
 108         r = fopen_temporary(fn, &f, &p);
 109         if (r < 0)
 110                 return r;
 111
 112         (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
 113         (void) fchmod_umask(fileno(f), 0644);
 114
 115         r = write_string_stream_ts(f, line, flags, ts);
 116         if (r < 0)
 117                 goto fail;
 118
 119         if (rename(p, fn) < 0) {
 120                 r = -errno;
 121                 goto fail;
 122         }
 123
 124         return 0;
 125
 126 fail:
 127         (void) unlink(p);
 128         return r;
 129 }
 130
 131 int write_string_file_ts(
 132                 const char *fn,
 133                 const char *line,
 134                 WriteStringFileFlags flags,
 135                 struct timespec *ts) {
 136
 137         _cleanup_fclose_ FILE *f = NULL;
 138         int q, r;
 139
 140         assert(fn);
 141         assert(line);
 142
 143         /* We don't know how to verify whether the file contents was already on-disk. */
 144         assert(!((flags & WRITE_STRING_FILE_VERIFY_ON_FAILURE) && (flags & WRITE_STRING_FILE_SYNC)));
 145
 146         if (flags & WRITE_STRING_FILE_ATOMIC) {
 147                 assert(flags & WRITE_STRING_FILE_CREATE);
 148
 149                 r = write_string_file_atomic(fn, line, flags, ts);
 150                 if (r < 0)
 151                         goto fail;
 152
 153                 return r;
 154         } else
 155                 assert(!ts);
 156
 157         if (flags & WRITE_STRING_FILE_CREATE) {
 158                 f = fopen(fn, "we");
 159                 if (!f) {
 160                         r = -errno;
 161                         goto fail;
 162                 }
 163         } else {
 164                 int fd;
 165
 166                 /* We manually build our own version of fopen(..., "we") that
 167                  * works without O_CREAT */
 168                 fd = open(fn, O_WRONLY|O_CLOEXEC|O_NOCTTY);
 169                 if (fd < 0) {
 170                         r = -errno;
 171                         goto fail;
 172                 }
 173
 174                 f = fdopen(fd, "we");
 175                 if (!f) {
 176                         r = -errno;
 177                         safe_close(fd);
 178                         goto fail;
 179                 }
 180         }
 181
 182         (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
 183
 184         if (flags & WRITE_STRING_FILE_DISABLE_BUFFER)
 185                 setvbuf(f, NULL, _IONBF, 0);
 186
 187         r = write_string_stream_ts(f, line, flags, ts);
 188         if (r < 0)
 189                 goto fail;
 190
 191         return 0;
 192
 193 fail:
 194         if (!(flags & WRITE_STRING_FILE_VERIFY_ON_FAILURE))
 195                 return r;
 196
 197         f = safe_fclose(f);
 198
 199         /* OK, the operation failed, but let's see if the right
 200          * contents in place already. If so, eat up the error. */
 201
 202         q = verify_file(fn, line, !(flags & WRITE_STRING_FILE_AVOID_NEWLINE));
 203         if (q <= 0)
 204                 return r;
 205
 206         return 0;
 207 }
 208
 209 int read_one_line_file(const char *fn, char **line) {
 210         _cleanup_fclose_ FILE *f = NULL;
 211         int r;
 212
 213         assert(fn);
 214         assert(line);
 215
 216         f = fopen(fn, "re");
 217         if (!f)
 218                 return -errno;
 219
 220         (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
 221
 222         r = read_line(f, LONG_LINE_MAX, line);
 223         return r < 0 ? r : 0;
 224 }
 225
 226 int verify_file(const char *fn, const char *blob, bool accept_extra_nl) {
 227         _cleanup_fclose_ FILE *f = NULL;
 228         _cleanup_free_ char *buf = NULL;
 229         size_t l, k;
 230
 231         assert(fn);
 232         assert(blob);
 233
 234         l = strlen(blob);
 235
 236         if (accept_extra_nl && endswith(blob, "\n"))
 237                 accept_extra_nl = false;
 238
 239         buf = malloc(l + accept_extra_nl + 1);
 240         if (!buf)
 241                 return -ENOMEM;
 242
 243         f = fopen(fn, "re");
 244         if (!f)
 245                 return -errno;
 246
 247         (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
 248
 249         /* We try to read one byte more than we need, so that we know whether we hit eof */
 250         errno = 0;
 251         k = fread(buf, 1, l + accept_extra_nl + 1, f);
 252         if (ferror(f))
 253                 return errno > 0 ? -errno : -EIO;
 254
 255         if (k != l && k != l + accept_extra_nl)
 256                 return 0;
 257         if (memcmp(buf, blob, l) != 0)
 258                 return 0;
 259         if (k > l && buf[l] != '\n')
 260                 return 0;
 261
 262         return 1;
 263 }
 264
 265 int read_full_stream(FILE *f, char **contents, size_t *size) {
 266         size_t n, l;
 267         _cleanup_free_ char *buf = NULL;
 268         struct stat st;
 269
 270         assert(f);
 271         assert(contents);
 272
 273         if (fstat(fileno(f), &st) < 0)
 274                 return -errno;
 275
 276         n = LINE_MAX;
 277
 278         if (S_ISREG(st.st_mode)) {
 279
 280                 /* Safety check */
 281                 if (st.st_size > READ_FULL_BYTES_MAX)
 282                         return -E2BIG;
 283
 284                 /* Start with the right file size, but be prepared for files from /proc which generally report a file
 285                  * size of 0. Note that we increase the size to read here by one, so that the first read attempt
 286                  * already makes us notice the EOF. */
 287                 if (st.st_size > 0)
 288                         n = st.st_size + 1;
 289         }
 290
 291         l = 0;
 292         for (;;) {
 293                 char *t;
 294                 size_t k;
 295
 296                 t = realloc(buf, n + 1);
 297                 if (!t)
 298                         return -ENOMEM;
 299
 300                 buf = t;
 301                 errno = 0;
 302                 k = fread(buf + l, 1, n - l, f);
 303                 if (k > 0)
 304                         l += k;
 305
 306                 if (ferror(f))
 307                         return errno > 0 ? -errno : -EIO;
 308
 309                 if (feof(f))
 310                         break;
 311
 312                 /* We aren't expecting fread() to return a short read outside
 313                  * of (error && eof), assert buffer is full and enlarge buffer.
 314                  */
 315                 assert(l == n);
 316
 317                 /* Safety check */
 318                 if (n >= READ_FULL_BYTES_MAX)
 319                         return -E2BIG;
 320
 321                 n = MIN(n * 2, READ_FULL_BYTES_MAX);
 322         }
 323
 324         buf[l] = 0;
 325         *contents = TAKE_PTR(buf);
 326
 327         if (size)
 328                 *size = l;
 329
 330         return 0;
 331 }
 332
 333 int read_full_file(const char *fn, char **contents, size_t *size) {
 334         _cleanup_fclose_ FILE *f = NULL;
 335
 336         assert(fn);
 337         assert(contents);
 338
 339         f = fopen(fn, "re");
 340         if (!f)
 341                 return -errno;
 342
 343         (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
 344
 345         return read_full_stream(f, contents, size);
 346 }
 347
 348 static int parse_env_file_internal(
 349                 FILE *f,
 350                 const char *fname,
 351                 const char *newline,
 352                 int (*push) (const char *filename, unsigned line,
 353                              const char *key, char *value, void *userdata, int *n_pushed),
 354                 void *userdata,
 355                 int *n_pushed) {
 356
 357         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;
 358         _cleanup_free_ char *contents = NULL, *key = NULL, *value = NULL;
 359         unsigned line = 1;
 360         char *p;
 361         int r;
 362
 363         enum {
 364                 PRE_KEY,
 365                 KEY,
 366                 PRE_VALUE,
 367                 VALUE,
 368                 VALUE_ESCAPE,
 369                 SINGLE_QUOTE_VALUE,
 370                 SINGLE_QUOTE_VALUE_ESCAPE,
 371                 DOUBLE_QUOTE_VALUE,
 372                 DOUBLE_QUOTE_VALUE_ESCAPE,
 373                 COMMENT,
 374                 COMMENT_ESCAPE
 375         } state = PRE_KEY;
 376
 377         assert(newline);
 378
 379         if (f)
 380                 r = read_full_stream(f, &contents, NULL);
 381         else
 382                 r = read_full_file(fname, &contents, NULL);
 383         if (r < 0)
 384                 return r;
 385
 386         for (p = contents; *p; p++) {
 387                 char c = *p;
 388
 389                 switch (state) {
 390
 391                 case PRE_KEY:
 392                         if (strchr(COMMENTS, c))
 393                                 state = COMMENT;
 394                         else if (!strchr(WHITESPACE, c)) {
 395                                 state = KEY;
 396                                 last_key_whitespace = (size_t) -1;
 397
 398                                 if (!GREEDY_REALLOC(key, key_alloc, n_key+2))
 399                                         return -ENOMEM;
 400
 401                                 key[n_key++] = c;
 402                         }
 403                         break;
 404
 405                 case KEY:
 406                         if (strchr(newline, c)) {
 407                                 state = PRE_KEY;
 408                                 line++;
 409                                 n_key = 0;
 410                         } else if (c == '=') {
 411                                 state = PRE_VALUE;
 412                                 last_value_whitespace = (size_t) -1;
 413                         } else {
 414                                 if (!strchr(WHITESPACE, c))
 415                                         last_key_whitespace = (size_t) -1;
 416                                 else if (last_key_whitespace == (size_t) -1)
 417                                          last_key_whitespace = n_key;
 418
 419                                 if (!GREEDY_REALLOC(key, key_alloc, n_key+2))
 420                                         return -ENOMEM;
 421
 422                                 key[n_key++] = c;
 423                         }
 424
 425                         break;
 426
 427                 case PRE_VALUE:
 428                         if (strchr(newline, c)) {
 429                                 state = PRE_KEY;
 430                                 line++;
 431                                 key[n_key] = 0;
 432
 433                                 if (value)
 434                                         value[n_value] = 0;
 435
 436                                 /* strip trailing whitespace from key */
 437                                 if (last_key_whitespace != (size_t) -1)
 438                                         key[last_key_whitespace] = 0;
 439
 440                                 r = push(fname, line, key, value, userdata, n_pushed);
 441                                 if (r < 0)
 442                                         return r;
 443
 444                                 n_key = 0;
 445                                 value = NULL;
 446                                 value_alloc = n_value = 0;
 447
 448                         } else if (c == '\'')
 449                                 state = SINGLE_QUOTE_VALUE;
 450                         else if (c == '\"')
 451                                 state = DOUBLE_QUOTE_VALUE;
 452                         else if (c == '\\')
 453                                 state = VALUE_ESCAPE;
 454                         else if (!strchr(WHITESPACE, c)) {
 455                                 state = VALUE;
 456
 457                                 if (!GREEDY_REALLOC(value, value_alloc, n_value+2))
 458                                         return  -ENOMEM;
 459
 460                                 value[n_value++] = c;
 461                         }
 462
 463                         break;
 464
 465                 case VALUE:
 466                         if (strchr(newline, c)) {
 467                                 state = PRE_KEY;
 468                                 line++;
 469
 470                                 key[n_key] = 0;
 471
 472                                 if (value)
 473                                         value[n_value] = 0;
 474
 475                                 /* Chomp off trailing whitespace from value */
 476                                 if (last_value_whitespace != (size_t) -1)
 477                                         value[last_value_whitespace] = 0;
 478
 479                                 /* strip trailing whitespace from key */
 480                                 if (last_key_whitespace != (size_t) -1)
 481                                         key[last_key_whitespace] = 0;
 482
 483                                 r = push(fname, line, key, value, userdata, n_pushed);
 484                                 if (r < 0)
 485                                         return r;
 486
 487                                 n_key = 0;
 488                                 value = NULL;
 489                                 value_alloc = n_value = 0;
 490
 491                         } else if (c == '\\') {
 492                                 state = VALUE_ESCAPE;
 493                                 last_value_whitespace = (size_t) -1;
 494                         } else {
 495                                 if (!strchr(WHITESPACE, c))
 496                                         last_value_whitespace = (size_t) -1;
 497                                 else if (last_value_whitespace == (size_t) -1)
 498                                         last_value_whitespace = n_value;
 499
 500                                 if (!GREEDY_REALLOC(value, value_alloc, n_value+2))
 501                                         return -ENOMEM;
 502
 503                                 value[n_value++] = c;
 504                         }
 505
 506                         break;
 507
 508                 case VALUE_ESCAPE:
 509                         state = VALUE;
 510
 511                         if (!strchr(newline, c)) {
 512                                 /* Escaped newlines we eat up entirely */
 513                                 if (!GREEDY_REALLOC(value, value_alloc, n_value+2))
 514                                         return -ENOMEM;
 515
 516                                 value[n_value++] = c;
 517                         }
 518                         break;
 519
 520                 case SINGLE_QUOTE_VALUE:
 521                         if (c == '\'')
 522                                 state = PRE_VALUE;
 523                         else if (c == '\\')
 524                                 state = SINGLE_QUOTE_VALUE_ESCAPE;
 525                         else {
 526                                 if (!GREEDY_REALLOC(value, value_alloc, n_value+2))
 527                                         return -ENOMEM;
 528
 529                                 value[n_value++] = c;
 530                         }
 531
 532                         break;
 533
 534                 case SINGLE_QUOTE_VALUE_ESCAPE:
 535                         state = SINGLE_QUOTE_VALUE;
 536
 537                         if (!strchr(newline, c)) {
 538                                 if (!GREEDY_REALLOC(value, value_alloc, n_value+2))
 539                                         return -ENOMEM;
 540
 541                                 value[n_value++] = c;
 542                         }
 543                         break;
 544
 545                 case DOUBLE_QUOTE_VALUE:
 546                         if (c == '\"')
 547                                 state = PRE_VALUE;
 548                         else if (c == '\\')
 549                                 state = DOUBLE_QUOTE_VALUE_ESCAPE;
 550                         else {
 551                                 if (!GREEDY_REALLOC(value, value_alloc, n_value+2))
 552                                         return -ENOMEM;
 553
 554                                 value[n_value++] = c;
 555                         }
 556
 557                         break;
 558
 559                 case DOUBLE_QUOTE_VALUE_ESCAPE:
 560                         state = DOUBLE_QUOTE_VALUE;
 561
 562                         if (!strchr(newline, c)) {
 563                                 if (!GREEDY_REALLOC(value, value_alloc, n_value+2))
 564                                         return -ENOMEM;
 565
 566                                 value[n_value++] = c;
 567                         }
 568                         break;
 569
 570                 case COMMENT:
 571                         if (c == '\\')
 572                                 state = COMMENT_ESCAPE;
 573                         else if (strchr(newline, c)) {
 574                                 state = PRE_KEY;
 575                                 line++;
 576                         }
 577                         break;
 578
 579                 case COMMENT_ESCAPE:
 580                         state = COMMENT;
 581                         break;
 582                 }
 583         }
 584
 585         if (IN_SET(state,
 586                    PRE_VALUE,
 587                    VALUE,
 588                    VALUE_ESCAPE,
 589                    SINGLE_QUOTE_VALUE,
 590                    SINGLE_QUOTE_VALUE_ESCAPE,
 591                    DOUBLE_QUOTE_VALUE,
 592                    DOUBLE_QUOTE_VALUE_ESCAPE)) {
 593
 594                 key[n_key] = 0;
 595
 596                 if (value)
 597                         value[n_value] = 0;
 598
 599                 if (state == VALUE)
 600                         if (last_value_whitespace != (size_t) -1)
 601                                 value[last_value_whitespace] = 0;
 602
 603                 /* strip trailing whitespace from key */
 604                 if (last_key_whitespace != (size_t) -1)
 605                         key[last_key_whitespace] = 0;
 606
 607                 r = push(fname, line, key, value, userdata, n_pushed);
 608                 if (r < 0)
 609                         return r;
 610
 611                 value = NULL;
 612         }
 613
 614         return 0;
 615 }
 616
 617 static int check_utf8ness_and_warn(
 618                 const char *filename, unsigned line,
 619                 const char *key, char *value) {
 620
 621         if (!utf8_is_valid(key)) {
 622                 _cleanup_free_ char *p = NULL;
 623
 624                 p = utf8_escape_invalid(key);
 625                 log_error("%s:%u: invalid UTF-8 in key '%s', ignoring.", strna(filename), line, p);
 626                 return -EINVAL;
 627         }
 628
 629         if (value && !utf8_is_valid(value)) {
 630                 _cleanup_free_ char *p = NULL;
 631
 632                 p = utf8_escape_invalid(value);
 633                 log_error("%s:%u: invalid UTF-8 value for key %s: '%s', ignoring.", strna(filename), line, key, p);
 634                 return -EINVAL;
 635         }
 636
 637         return 0;
 638 }
 639
 640 static int parse_env_file_push(
 641                 const char *filename, unsigned line,
 642                 const char *key, char *value,
 643                 void *userdata,
 644                 int *n_pushed) {
 645
 646         const char *k;
 647         va_list aq, *ap = userdata;
 648         int r;
 649
 650         r = check_utf8ness_and_warn(filename, line, key, value);
 651         if (r < 0)
 652                 return r;
 653
 654         va_copy(aq, *ap);
 655
 656         while ((k = va_arg(aq, const char *))) {
 657                 char **v;
 658
 659                 v = va_arg(aq, char **);
 660
 661                 if (streq(key, k)) {
 662                         va_end(aq);
 663                         free(*v);
 664                         *v = value;
 665
 666                         if (n_pushed)
 667                                 (*n_pushed)++;
 668
 669                         return 1;
 670                 }
 671         }
 672
 673         va_end(aq);
 674         free(value);
 675
 676         return 0;
 677 }
 678
 679 int parse_env_file(
 680                 FILE *f,
 681                 const char *fname,
 682                 const char *newline, ...) {
 683
 684         va_list ap;
 685         int r, n_pushed = 0;
 686
 687         if (!newline)
 688                 newline = NEWLINE;
 689
 690         va_start(ap, newline);
 691         r = parse_env_file_internal(f, fname, newline, parse_env_file_push, &ap, &n_pushed);
 692         va_end(ap);
 693
 694         return r < 0 ? r : n_pushed;
 695 }
 696
 697 static int load_env_file_push(
 698                 const char *filename, unsigned line,
 699                 const char *key, char *value,
 700                 void *userdata,
 701                 int *n_pushed) {
 702         char ***m = userdata;
 703         char *p;
 704         int r;
 705
 706         r = check_utf8ness_and_warn(filename, line, key, value);
 707         if (r < 0)
 708                 return r;
 709
 710         p = strjoin(key, "=", value);
 711         if (!p)
 712                 return -ENOMEM;
 713
 714         r = strv_env_replace(m, p);
 715         if (r < 0) {
 716                 free(p);
 717                 return r;
 718         }
 719
 720         if (n_pushed)
 721                 (*n_pushed)++;
 722
 723         free(value);
 724         return 0;
 725 }
 726
 727 int load_env_file(FILE *f, const char *fname, const char *newline, char ***rl) {
 728         char **m = NULL;
 729         int r;
 730
 731         if (!newline)
 732                 newline = NEWLINE;
 733
 734         r = parse_env_file_internal(f, fname, newline, load_env_file_push, &m, NULL);
 735         if (r < 0) {
 736                 strv_free(m);
 737                 return r;
 738         }
 739
 740         *rl = m;
 741         return 0;
 742 }
 743
 744 static int load_env_file_push_pairs(
 745                 const char *filename, unsigned line,
 746                 const char *key, char *value,
 747                 void *userdata,
 748                 int *n_pushed) {
 749         char ***m = userdata;
 750         int r;
 751
 752         r = check_utf8ness_and_warn(filename, line, key, value);
 753         if (r < 0)
 754                 return r;
 755
 756         r = strv_extend(m, key);
 757         if (r < 0)
 758                 return -ENOMEM;
 759
 760         if (!value) {
 761                 r = strv_extend(m, "");
 762                 if (r < 0)
 763                         return -ENOMEM;
 764         } else {
 765                 r = strv_push(m, value);
 766                 if (r < 0)
 767                         return r;
 768         }
 769
 770         if (n_pushed)
 771                 (*n_pushed)++;
 772
 773         return 0;
 774 }
 775
 776 int load_env_file_pairs(FILE *f, const char *fname, const char *newline, char ***rl) {
 777         char **m = NULL;
 778         int r;
 779
 780         if (!newline)
 781                 newline = NEWLINE;
 782
 783         r = parse_env_file_internal(f, fname, newline, load_env_file_push_pairs, &m, NULL);
 784         if (r < 0) {
 785                 strv_free(m);
 786                 return r;
 787         }
 788
 789         *rl = m;
 790         return 0;
 791 }
 792
 793 static int merge_env_file_push(
 794                 const char *filename, unsigned line,
 795                 const char *key, char *value,
 796                 void *userdata,
 797                 int *n_pushed) {
 798
 799         char ***env = userdata;
 800         char *expanded_value;
 801
 802         assert(env);
 803
 804         if (!value) {
 805                 log_error("%s:%u: invalid syntax (around \"%s\"), ignoring.", strna(filename), line, key);
 806                 return 0;
 807         }
 808
 809         if (!env_name_is_valid(key)) {
 810                 log_error("%s:%u: invalid variable name \"%s\", ignoring.", strna(filename), line, key);
 811                 free(value);
 812                 return 0;
 813         }
 814
 815         expanded_value = replace_env(value, *env,
 816                                      REPLACE_ENV_USE_ENVIRONMENT|
 817                                      REPLACE_ENV_ALLOW_BRACELESS|
 818                                      REPLACE_ENV_ALLOW_EXTENDED);
 819         if (!expanded_value)
 820                 return -ENOMEM;
 821
 822         free_and_replace(value, expanded_value);
 823
 824         return load_env_file_push(filename, line, key, value, env, n_pushed);
 825 }
 826
 827 int merge_env_file(
 828                 char ***env,
 829                 FILE *f,
 830                 const char *fname) {
 831
 832         /* NOTE: this function supports braceful and braceless variable expansions,
 833          * plus "extended" substitutions, unlike other exported parsing functions.
 834          */
 835
 836         return parse_env_file_internal(f, fname, NEWLINE, merge_env_file_push, env, NULL);
 837 }
 838
 839 static void write_env_var(FILE *f, const char *v) {
 840         const char *p;
 841
 842         p = strchr(v, '=');
 843         if (!p) {
 844                 /* Fallback */
 845                 fputs_unlocked(v, f);
 846                 fputc_unlocked('\n', f);
 847                 return;
 848         }
 849
 850         p++;
 851         fwrite_unlocked(v, 1, p-v, f);
 852
 853         if (string_has_cc(p, NULL) || chars_intersect(p, WHITESPACE SHELL_NEED_QUOTES)) {
 854                 fputc_unlocked('\"', f);
 855
 856                 for (; *p; p++) {
 857                         if (strchr(SHELL_NEED_ESCAPE, *p))
 858                                 fputc_unlocked('\\', f);
 859
 860                         fputc_unlocked(*p, f);
 861                 }
 862
 863                 fputc_unlocked('\"', f);
 864         } else
 865                 fputs_unlocked(p, f);
 866
 867         fputc_unlocked('\n', f);
 868 }
 869
 870 int write_env_file(const char *fname, char **l) {
 871         _cleanup_fclose_ FILE *f = NULL;
 872         _cleanup_free_ char *p = NULL;
 873         char **i;
 874         int r;
 875
 876         assert(fname);
 877
 878         r = fopen_temporary(fname, &f, &p);
 879         if (r < 0)
 880                 return r;
 881
 882         (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
 883         (void) fchmod_umask(fileno(f), 0644);
 884
 885         STRV_FOREACH(i, l)
 886                 write_env_var(f, *i);
 887
 888         r = fflush_and_check(f);
 889         if (r >= 0) {
 890                 if (rename(p, fname) >= 0)
 891                         return 0;
 892
 893                 r = -errno;
 894         }
 895
 896         unlink(p);
 897         return r;
 898 }
 899
 900 int executable_is_script(const char *path, char **interpreter) {
 901         _cleanup_free_ char *line = NULL;
 902         size_t len;
 903         char *ans;
 904         int r;
 905
 906         assert(path);
 907
 908         r = read_one_line_file(path, &line);
 909         if (r == -ENOBUFS) /* First line overly long? if so, then it's not a script */
 910                 return 0;
 911         if (r < 0)
 912                 return r;
 913
 914         if (!startswith(line, "#!"))
 915                 return 0;
 916
 917         ans = strstrip(line + 2);
 918         len = strcspn(ans, " \t");
 919
 920         if (len == 0)
 921                 return 0;
 922
 923         ans = strndup(ans, len);
 924         if (!ans)
 925                 return -ENOMEM;
 926
 927         *interpreter = ans;
 928         return 1;
 929 }
 930
 931 /**
 932  * Retrieve one field from a file like /proc/self/status.  pattern
 933  * should not include whitespace or the delimiter (':'). pattern matches only
 934  * the beginning of a line. Whitespace before ':' is skipped. Whitespace and
 935  * zeros after the ':' will be skipped. field must be freed afterwards.
 936  * terminator specifies the terminating characters of the field value (not
 937  * included in the value).
 938  */
 939 int get_proc_field(const char *filename, const char *pattern, const char *terminator, char **field) {
 940         _cleanup_free_ char *status = NULL;
 941         char *t, *f;
 942         size_t len;
 943         int r;
 944
 945         assert(terminator);
 946         assert(filename);
 947         assert(pattern);
 948         assert(field);
 949
 950         r = read_full_file(filename, &status, NULL);
 951         if (r < 0)
 952                 return r;
 953
 954         t = status;
 955
 956         do {
 957                 bool pattern_ok;
 958
 959                 do {
 960                         t = strstr(t, pattern);
 961                         if (!t)
 962                                 return -ENOENT;
 963
 964                         /* Check that pattern occurs in beginning of line. */
 965                         pattern_ok = (t == status || t[-1] == '\n');
 966
 967                         t += strlen(pattern);
 968
 969                 } while (!pattern_ok);
 970
 971                 t += strspn(t, " \t");
 972                 if (!*t)
 973                         return -ENOENT;
 974
 975         } while (*t != ':');
 976
 977         t++;
 978
 979         if (*t) {
 980                 t += strspn(t, " \t");
 981
 982                 /* Also skip zeros, because when this is used for
 983                  * capabilities, we don't want the zeros. This way the
 984                  * same capability set always maps to the same string,
 985                  * irrespective of the total capability set size. For
 986                  * other numbers it shouldn't matter. */
 987                 t += strspn(t, "0");
 988                 /* Back off one char if there's nothing but whitespace
 989                    and zeros */
 990                 if (!*t || isspace(*t))
 991                         t--;
 992         }
 993
 994         len = strcspn(t, terminator);
 995
 996         f = strndup(t, len);
 997         if (!f)
 998                 return -ENOMEM;
 999
1000         *field = f;
1001         return 0;
1002 }
1003
1004 DIR *xopendirat(int fd, const char *name, int flags) {
1005         int nfd;
1006         DIR *d;
1007
1008         assert(!(flags & O_CREAT));
1009
1010         nfd = openat(fd, name, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|flags, 0);
1011         if (nfd < 0)
1012                 return NULL;
1013
1014         d = fdopendir(nfd);
1015         if (!d) {
1016                 safe_close(nfd);
1017                 return NULL;
1018         }
1019
1020         return d;
1021 }
1022
1023 static int search_and_fopen_internal(const char *path, const char *mode, const char *root, char **search, FILE **_f) {
1024         char **i;
1025
1026         assert(path);
1027         assert(mode);
1028         assert(_f);
1029
1030         if (!path_strv_resolve_uniq(search, root))
1031                 return -ENOMEM;
1032
1033         STRV_FOREACH(i, search) {
1034                 _cleanup_free_ char *p = NULL;
1035                 FILE *f;
1036
1037                 if (root)
1038                         p = strjoin(root, *i, "/", path);
1039                 else
1040                         p = strjoin(*i, "/", path);
1041                 if (!p)
1042                         return -ENOMEM;
1043
1044                 f = fopen(p, mode);
1045                 if (f) {
1046                         *_f = f;
1047                         return 0;
1048                 }
1049
1050                 if (errno != ENOENT)
1051                         return -errno;
1052         }
1053
1054         return -ENOENT;
1055 }
1056
1057 int search_and_fopen(const char *path, const char *mode, const char *root, const char **search, FILE **_f) {
1058         _cleanup_strv_free_ char **copy = NULL;
1059
1060         assert(path);
1061         assert(mode);
1062         assert(_f);
1063
1064         if (path_is_absolute(path)) {
1065                 FILE *f;
1066
1067                 f = fopen(path, mode);
1068                 if (f) {
1069                         *_f = f;
1070                         return 0;
1071                 }
1072
1073                 return -errno;
1074         }
1075
1076         copy = strv_copy((char**) search);
1077         if (!copy)
1078                 return -ENOMEM;
1079
1080         return search_and_fopen_internal(path, mode, root, copy, _f);
1081 }
1082
1083 int search_and_fopen_nulstr(const char *path, const char *mode, const char *root, const char *search, FILE **_f) {
1084         _cleanup_strv_free_ char **s = NULL;
1085
1086         if (path_is_absolute(path)) {
1087                 FILE *f;
1088
1089                 f = fopen(path, mode);
1090                 if (f) {
1091                         *_f = f;
1092                         return 0;
1093                 }
1094
1095                 return -errno;
1096         }
1097
1098         s = strv_split_nulstr(search);
1099         if (!s)
1100                 return -ENOMEM;
1101
1102         return search_and_fopen_internal(path, mode, root, s, _f);
1103 }
1104
1105 int fopen_temporary(const char *path, FILE **_f, char **_temp_path) {
1106         FILE *f;
1107         char *t;
1108         int r, fd;
1109
1110         assert(path);
1111         assert(_f);
1112         assert(_temp_path);
1113
1114         r = tempfn_xxxxxx(path, NULL, &t);
1115         if (r < 0)
1116                 return r;
1117
1118         fd = mkostemp_safe(t);
1119         if (fd < 0) {
1120                 free(t);
1121                 return -errno;
1122         }
1123
1124         f = fdopen(fd, "we");
1125         if (!f) {
1126                 unlink_noerrno(t);
1127                 free(t);
1128                 safe_close(fd);
1129                 return -errno;
1130         }
1131
1132         *_f = f;
1133         *_temp_path = t;
1134
1135         return 0;
1136 }
1137
1138 int fflush_and_check(FILE *f) {
1139         assert(f);
1140
1141         errno = 0;
1142         fflush(f);
1143
1144         if (ferror(f))
1145                 return errno > 0 ? -errno : -EIO;
1146
1147         return 0;
1148 }
1149
1150 int fflush_sync_and_check(FILE *f) {
1151         int r;
1152
1153         assert(f);
1154
1155         r = fflush_and_check(f);
1156         if (r < 0)
1157                 return r;
1158
1159         if (fsync(fileno(f)) < 0)
1160                 return -errno;
1161
1162         r = fsync_directory_of_file(fileno(f));
1163         if (r < 0)
1164                 return r;
1165
1166         return 0;
1167 }
1168
1169 /* This is much like mkostemp() but is subject to umask(). */
1170 int mkostemp_safe(char *pattern) {
1171         _cleanup_umask_ mode_t u = 0;
1172         int fd;
1173
1174         assert(pattern);
1175
1176         u = umask(077);
1177
1178         fd = mkostemp(pattern, O_CLOEXEC);
1179         if (fd < 0)
1180                 return -errno;
1181
1182         return fd;
1183 }
1184
1185 int tempfn_xxxxxx(const char *p, const char *extra, char **ret) {
1186         const char *fn;
1187         char *t;
1188
1189         assert(p);
1190         assert(ret);
1191
1192         /*
1193          * Turns this:
1194          *         /foo/bar/waldo
1195          *
1196          * Into this:
1197          *         /foo/bar/.#<extra>waldoXXXXXX
1198          */
1199
1200         fn = basename(p);
1201         if (!filename_is_valid(fn))
1202                 return -EINVAL;
1203
1204         extra = strempty(extra);
1205
1206         t = new(char, strlen(p) + 2 + strlen(extra) + 6 + 1);
1207         if (!t)
1208                 return -ENOMEM;
1209
1210         strcpy(stpcpy(stpcpy(stpcpy(mempcpy(t, p, fn - p), ".#"), extra), fn), "XXXXXX");
1211
1212         *ret = path_kill_slashes(t);
1213         return 0;
1214 }
1215
1216 int tempfn_random(const char *p, const char *extra, char **ret) {
1217         const char *fn;
1218         char *t, *x;
1219         uint64_t u;
1220         unsigned i;
1221
1222         assert(p);
1223         assert(ret);
1224
1225         /*
1226          * Turns this:
1227          *         /foo/bar/waldo
1228          *
1229          * Into this:
1230          *         /foo/bar/.#<extra>waldobaa2a261115984a9
1231          */
1232
1233         fn = basename(p);
1234         if (!filename_is_valid(fn))
1235                 return -EINVAL;
1236
1237         extra = strempty(extra);
1238
1239         t = new(char, strlen(p) + 2 + strlen(extra) + 16 + 1);
1240         if (!t)
1241                 return -ENOMEM;
1242
1243         x = stpcpy(stpcpy(stpcpy(mempcpy(t, p, fn - p), ".#"), extra), fn);
1244
1245         u = random_u64();
1246         for (i = 0; i < 16; i++) {
1247                 *(x++) = hexchar(u & 0xF);
1248                 u >>= 4;
1249         }
1250
1251         *x = 0;
1252
1253         *ret = path_kill_slashes(t);
1254         return 0;
1255 }
1256
1257 int tempfn_random_child(const char *p, const char *extra, char **ret) {
1258         char *t, *x;
1259         uint64_t u;
1260         unsigned i;
1261         int r;
1262
1263         assert(ret);
1264
1265         /* Turns this:
1266          *         /foo/bar/waldo
1267          * Into this:
1268          *         /foo/bar/waldo/.#<extra>3c2b6219aa75d7d0
1269          */
1270
1271         if (!p) {
1272                 r = tmp_dir(&p);
1273                 if (r < 0)
1274                         return r;
1275         }
1276
1277         extra = strempty(extra);
1278
1279         t = new(char, strlen(p) + 3 + strlen(extra) + 16 + 1);
1280         if (!t)
1281                 return -ENOMEM;
1282
1283         x = stpcpy(stpcpy(stpcpy(t, p), "/.#"), extra);
1284
1285         u = random_u64();
1286         for (i = 0; i < 16; i++) {
1287                 *(x++) = hexchar(u & 0xF);
1288                 u >>= 4;
1289         }
1290
1291         *x = 0;
1292
1293         *ret = path_kill_slashes(t);
1294         return 0;
1295 }
1296
1297 int write_timestamp_file_atomic(const char *fn, usec_t n) {
1298         char ln[DECIMAL_STR_MAX(n)+2];
1299
1300         /* Creates a "timestamp" file, that contains nothing but a
1301          * usec_t timestamp, formatted in ASCII. */
1302
1303         if (n <= 0 || n >= USEC_INFINITY)
1304                 return -ERANGE;
1305
1306         xsprintf(ln, USEC_FMT "\n", n);
1307
1308         return write_string_file(fn, ln, WRITE_STRING_FILE_CREATE|WRITE_STRING_FILE_ATOMIC);
1309 }
1310
1311 int read_timestamp_file(const char *fn, usec_t *ret) {
1312         _cleanup_free_ char *ln = NULL;
1313         uint64_t t;
1314         int r;
1315
1316         r = read_one_line_file(fn, &ln);
1317         if (r < 0)
1318                 return r;
1319
1320         r = safe_atou64(ln, &t);
1321         if (r < 0)
1322                 return r;
1323
1324         if (t <= 0 || t >= (uint64_t) USEC_INFINITY)
1325                 return -ERANGE;
1326
1327         *ret = (usec_t) t;
1328         return 0;
1329 }
1330
1331 int fputs_with_space(FILE *f, const char *s, const char *separator, bool *space) {
1332         int r;
1333
1334         assert(s);
1335
1336         /* Outputs the specified string with fputs(), but optionally prefixes it with a separator. The *space parameter
1337          * when specified shall initially point to a boolean variable initialized to false. It is set to true after the
1338          * first invocation. This call is supposed to be use in loops, where a separator shall be inserted between each
1339          * element, but not before the first one. */
1340
1341         if (!f)
1342                 f = stdout;
1343
1344         if (space) {
1345                 if (!separator)
1346                         separator = " ";
1347
1348                 if (*space) {
1349                         r = fputs(separator, f);
1350                         if (r < 0)
1351                                 return r;
1352                 }
1353
1354                 *space = true;
1355         }
1356
1357         return fputs(s, f);
1358 }
1359
1360 int open_tmpfile_unlinkable(const char *directory, int flags) {
1361         char *p;
1362         int fd, r;
1363
1364         if (!directory) {
1365                 r = tmp_dir(&directory);
1366                 if (r < 0)
1367                         return r;
1368         }
1369
1370         /* Returns an unlinked temporary file that cannot be linked into the file system anymore */
1371
1372         /* Try O_TMPFILE first, if it is supported */
1373         fd = open(directory, flags|O_TMPFILE|O_EXCL, S_IRUSR|S_IWUSR);
1374         if (fd >= 0)
1375                 return fd;
1376
1377         /* Fall back to unguessable name + unlinking */
1378         p = strjoina(directory, "/systemd-tmp-XXXXXX");
1379
1380         fd = mkostemp_safe(p);
1381         if (fd < 0)
1382                 return fd;
1383
1384         (void) unlink(p);
1385
1386         return fd;
1387 }
1388
1389 int open_tmpfile_linkable(const char *target, int flags, char **ret_path) {
1390         _cleanup_free_ char *tmp = NULL;
1391         int r, fd;
1392
1393         assert(target);
1394         assert(ret_path);
1395
1396         /* Don't allow O_EXCL, as that has a special meaning for O_TMPFILE */
1397         assert((flags & O_EXCL) == 0);
1398
1399         /* Creates a temporary file, that shall be renamed to "target" later. If possible, this uses O_TMPFILE – in
1400          * which case "ret_path" will be returned as NULL. If not possible a the tempoary path name used is returned in
1401          * "ret_path". Use link_tmpfile() below to rename the result after writing the file in full. */
1402
1403         {
1404                 _cleanup_free_ char *dn = NULL;
1405
1406                 dn = dirname_malloc(target);
1407                 if (!dn)
1408                         return -ENOMEM;
1409
1410                 fd = open(dn, O_TMPFILE|flags, 0640);
1411                 if (fd >= 0) {
1412                         *ret_path = NULL;
1413                         return fd;
1414                 }
1415
1416                 log_debug_errno(errno, "Failed to use O_TMPFILE on %s: %m", dn);
1417         }
1418
1419         r = tempfn_random(target, NULL, &tmp);
1420         if (r < 0)
1421                 return r;
1422
1423         fd = open(tmp, O_CREAT|O_EXCL|O_NOFOLLOW|O_NOCTTY|flags, 0640);
1424         if (fd < 0)
1425                 return -errno;
1426
1427         *ret_path = TAKE_PTR(tmp);
1428
1429         return fd;
1430 }
1431
1432 int open_serialization_fd(const char *ident) {
1433         int fd = -1;
1434
1435         fd = memfd_create(ident, MFD_CLOEXEC);
1436         if (fd < 0) {
1437                 const char *path;
1438
1439                 path = getpid_cached() == 1 ? "/run/systemd" : "/tmp";
1440                 fd = open_tmpfile_unlinkable(path, O_RDWR|O_CLOEXEC);
1441                 if (fd < 0)
1442                         return fd;
1443
1444                 log_debug("Serializing %s to %s.", ident, path);
1445         } else
1446                 log_debug("Serializing %s to memfd.", ident);
1447
1448         return fd;
1449 }
1450
1451 int link_tmpfile(int fd, const char *path, const char *target) {
1452
1453         assert(fd >= 0);
1454         assert(target);
1455
1456         /* Moves a temporary file created with open_tmpfile() above into its final place. if "path" is NULL an fd
1457          * created with O_TMPFILE is assumed, and linkat() is used. Otherwise it is assumed O_TMPFILE is not supported
1458          * on the directory, and renameat2() is used instead.
1459          *
1460          * Note that in both cases we will not replace existing files. This is because linkat() does not support this
1461          * operation currently (renameat2() does), and there is no nice way to emulate this. */
1462
1463         if (path) {
1464                 if (rename_noreplace(AT_FDCWD, path, AT_FDCWD, target) < 0)
1465                         return -errno;
1466         } else {
1467                 char proc_fd_path[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(fd) + 1];
1468
1469                 xsprintf(proc_fd_path, "/proc/self/fd/%i", fd);
1470
1471                 if (linkat(AT_FDCWD, proc_fd_path, AT_FDCWD, target, AT_SYMLINK_FOLLOW) < 0)
1472                         return -errno;
1473         }
1474
1475         return 0;
1476 }
1477
1478 int read_nul_string(FILE *f, char **ret) {
1479         _cleanup_free_ char *x = NULL;
1480         size_t allocated = 0, n = 0;
1481
1482         assert(f);
1483         assert(ret);
1484
1485         /* Reads a NUL-terminated string from the specified file. */
1486
1487         for (;;) {
1488                 int c;
1489
1490                 if (!GREEDY_REALLOC(x, allocated, n+2))
1491                         return -ENOMEM;
1492
1493                 c = fgetc(f);
1494                 if (c == 0) /* Terminate at NUL byte */
1495                         break;
1496                 if (c == EOF) {
1497                         if (ferror(f))
1498                                 return -errno;
1499                         break; /* Terminate at EOF */
1500                 }
1501
1502                 x[n++] = (char) c;
1503         }
1504
1505         if (x)
1506                 x[n] = 0;
1507         else {
1508                 x = new0(char, 1);
1509                 if (!x)
1510                         return -ENOMEM;
1511         }
1512
1513         *ret = TAKE_PTR(x);
1514
1515         return 0;
1516 }
1517
1518 int mkdtemp_malloc(const char *template, char **ret) {
1519         char *p;
1520
1521         assert(template);
1522         assert(ret);
1523
1524         p = strdup(template);
1525         if (!p)
1526                 return -ENOMEM;
1527
1528         if (!mkdtemp(p)) {
1529                 free(p);
1530                 return -errno;
1531         }
1532
1533         *ret = p;
1534         return 0;
1535 }
1536
1537 DEFINE_TRIVIAL_CLEANUP_FUNC(FILE*, funlockfile);
1538
1539 int read_line(FILE *f, size_t limit, char **ret) {
1540         _cleanup_free_ char *buffer = NULL;
1541         size_t n = 0, allocated = 0, count = 0;
1542
1543         assert(f);
1544
1545         /* Something like a bounded version of getline().
1546          *
1547          * Considers EOF, \n and \0 end of line delimiters, and does not include these delimiters in the string
1548          * returned.
1549          *
1550          * Returns the number of bytes read from the files (i.e. including delimiters — this hence usually differs from
1551          * the number of characters in the returned string). When EOF is hit, 0 is returned.
1552          *
1553          * The input parameter limit is the maximum numbers of characters in the returned string, i.e. excluding
1554          * delimiters. If the limit is hit we fail and return -ENOBUFS.
1555          *
1556          * If a line shall be skipped ret may be initialized as NULL. */
1557
1558         if (ret) {
1559                 if (!GREEDY_REALLOC(buffer, allocated, 1))
1560                         return -ENOMEM;
1561         }
1562
1563         {
1564                 _unused_ _cleanup_(funlockfilep) FILE *flocked = f;
1565                 flockfile(f);
1566
1567                 for (;;) {
1568                         int c;
1569
1570                         if (n >= limit)
1571                                 return -ENOBUFS;
1572
1573                         errno = 0;
1574                         c = fgetc_unlocked(f);
1575                         if (c == EOF) {
1576                                 /* if we read an error, and have no data to return, then propagate the error */
1577                                 if (ferror_unlocked(f) && n == 0)
1578                                         return errno > 0 ? -errno : -EIO;
1579
1580                                 break;
1581                         }
1582
1583                         count++;
1584
1585                         if (IN_SET(c, '\n', 0)) /* Reached a delimiter */
1586                                 break;
1587
1588                         if (ret) {
1589                                 if (!GREEDY_REALLOC(buffer, allocated, n + 2))
1590                                         return -ENOMEM;
1591
1592                                 buffer[n] = (char) c;
1593                         }
1594
1595                         n++;
1596                 }
1597         }
1598
1599         if (ret) {
1600                 buffer[n] = 0;
1601
1602                 *ret = TAKE_PTR(buffer);
1603         }
1604
1605         return (int) count;
1606 }