src/basic/fileio.c

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