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