src/basic/fileio.c

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