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