src/common/file-utils.c

   1 /*
   2  * Claws Mail -- a GTK+ based, lightweight, and fast e-mail client
   3  * Copyright (C) 1999-2018 Colin Leroy and the Claws Mail team
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 3 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #ifdef HAVE_CONFIG_H
  20 #  include "config.h"
  21 #include "claws-features.h"
  22 #endif
  23
  24 #include <errno.h>
  25 #include <stdio.h>
  26 #include <unistd.h>
  27 #include <fcntl.h>
  28
  29 #include "defs.h"
  30 #include "codeconv.h"
  31 #include "timing.h"
  32 #include "file-utils.h"
  33
  34 gboolean prefs_common_get_flush_metadata(void);
  35 gboolean prefs_common_get_use_shred(void);
  36
  37 /* FIXME make static once every file I/O is done using claws_* wrappers */
  38 int safe_fclose(FILE *fp)
  39 {
  40         int r;
  41         START_TIMING("");
  42
  43         if (fflush(fp) != 0) {
  44                 return EOF;
  45         }
  46         if (prefs_common_get_flush_metadata() && fsync(fileno(fp)) != 0) {
  47                 return EOF;
  48         }
  49
  50         r = fclose(fp);
  51         END_TIMING();
  52
  53         return r;
  54 }
  55
  56 #if HAVE_FGETS_UNLOCKED
  57
  58 /* Open a file and locks it once
  59  * so subsequent I/O is faster
  60  */
  61 FILE *claws_fopen(const char *file, const char *mode)
  62 {
  63         FILE *fp = fopen(file, mode);
  64         if (!fp)
  65                 return NULL;
  66         flockfile(fp);
  67         return fp;
  68 }
  69
  70 FILE *claws_fdopen(int fd, const char *mode)
  71 {
  72         FILE *fp = fdopen(fd, mode);
  73         if (!fp)
  74                 return NULL;
  75         flockfile(fp);
  76         return fp;
  77 }
  78
  79 /* Unlocks and close a file pointer
  80  */
  81
  82 int claws_fclose(FILE *fp)
  83 {
  84         funlockfile(fp);
  85         return fclose(fp);
  86 }
  87
  88 /* Unlock, then safe-close a file pointer
  89  * Safe close is done using fflush + fsync
  90  * if the according preference says so.
  91  */
  92 int claws_safe_fclose(FILE *fp)
  93 {
  94         funlockfile(fp);
  95         return safe_fclose(fp);
  96 }
  97
  98 #ifdef G_OS_WIN32
  99 #define WEXITSTATUS(x) (x)
 100 #endif
 101
 102 int claws_unlink(const char *filename)
 103 {
 104         GStatBuf s;
 105         static int found_shred = -1;
 106         static const gchar *args[4];
 107
 108         if (filename == NULL)
 109                 return 0;
 110
 111         if (prefs_common_get_use_shred()) {
 112                 if (found_shred == -1) {
 113                         /* init */
 114                         args[0] = g_find_program_in_path("shred");
 115                         debug_print("found shred: %s\n", args[0]);
 116                         found_shred = (args[0] != NULL) ? 1:0;
 117                         args[1] = "-f";
 118                         args[3] = NULL;
 119                 }
 120                 if (found_shred == 1) {
 121                         if (g_stat(filename, &s) == 0 && S_ISREG(s.st_mode)) {
 122                                 if (s.st_nlink == 1) {
 123                                         gint status=0;
 124                                         args[2] = filename;
 125                                         g_spawn_sync(NULL, (gchar **)args, NULL, 0,
 126                                          NULL, NULL, NULL, NULL, &status, NULL);
 127                                         debug_print("%s %s exited with status %d\n",
 128                                                 args[0], filename, WEXITSTATUS(status));
 129                                         if (truncate(filename, 0) < 0)
 130                                                 g_warning("couln't truncate: %s", filename);
 131                                 }
 132                         }
 133                 }
 134         }
 135         return g_unlink(filename);
 136 }
 137
 138 gint file_strip_crs(const gchar *file)
 139 {
 140         FILE *fp = NULL, *outfp = NULL;
 141         gchar buf[4096];
 142         gchar *out = get_tmp_file();
 143         if (file == NULL)
 144                 goto freeout;
 145
 146         fp = claws_fopen(file, "rb");
 147         if (!fp)
 148                 goto freeout;
 149
 150         outfp = claws_fopen(out, "wb");
 151         if (!outfp) {
 152                 claws_fclose(fp);
 153                 goto freeout;
 154         }
 155
 156         while (claws_fgets(buf, sizeof (buf), fp) != NULL) {
 157                 strcrchomp(buf);
 158                 if (claws_fputs(buf, outfp) == EOF) {
 159                         claws_fclose(fp);
 160                         claws_fclose(outfp);
 161                         goto unlinkout;
 162                 }
 163         }
 164
 165         claws_fclose(fp);
 166         if (claws_safe_fclose(outfp) == EOF) {
 167                 goto unlinkout;
 168         }
 169
 170         if (move_file(out, file, TRUE) < 0)
 171                 goto unlinkout;
 172
 173         g_free(out);
 174         return 0;
 175 unlinkout:
 176         claws_unlink(out);
 177 freeout:
 178         g_free(out);
 179         return -1;
 180 }
 181
 182 /*
 183  * Append src file body to the tail of dest file.
 184  * Now keep_backup has no effects.
 185  */
 186 gint append_file(const gchar *src, const gchar *dest, gboolean keep_backup)
 187 {
 188         FILE *src_fp, *dest_fp;
 189         gint n_read;
 190         gchar buf[BUFSIZ];
 191
 192         gboolean err = FALSE;
 193
 194         if ((src_fp = claws_fopen(src, "rb")) == NULL) {
 195                 FILE_OP_ERROR(src, "claws_fopen");
 196                 return -1;
 197         }
 198
 199         if ((dest_fp = claws_fopen(dest, "ab")) == NULL) {
 200                 FILE_OP_ERROR(dest, "claws_fopen");
 201                 claws_fclose(src_fp);
 202                 return -1;
 203         }
 204
 205         if (change_file_mode_rw(dest_fp, dest) < 0) {
 206                 FILE_OP_ERROR(dest, "chmod");
 207                 g_warning("can't change file mode: %s", dest);
 208         }
 209
 210         while ((n_read = claws_fread(buf, sizeof(gchar), sizeof(buf), src_fp)) > 0) {
 211                 if (n_read < sizeof(buf) && claws_ferror(src_fp))
 212                         break;
 213                 if (claws_fwrite(buf, 1, n_read, dest_fp) < n_read) {
 214                         g_warning("writing to %s failed.", dest);
 215                         claws_fclose(dest_fp);
 216                         claws_fclose(src_fp);
 217                         claws_unlink(dest);
 218                         return -1;
 219                 }
 220         }
 221
 222         if (claws_ferror(src_fp)) {
 223                 FILE_OP_ERROR(src, "claws_fread");
 224                 err = TRUE;
 225         }
 226         claws_fclose(src_fp);
 227         if (claws_fclose(dest_fp) == EOF) {
 228                 FILE_OP_ERROR(dest, "claws_fclose");
 229                 err = TRUE;
 230         }
 231
 232         if (err) {
 233                 claws_unlink(dest);
 234                 return -1;
 235         }
 236
 237         return 0;
 238 }
 239
 240 gint copy_file(const gchar *src, const gchar *dest, gboolean keep_backup)
 241 {
 242         FILE *src_fp, *dest_fp;
 243         gint n_read;
 244         gchar buf[BUFSIZ];
 245         gchar *dest_bak = NULL;
 246         gboolean err = FALSE;
 247
 248         if ((src_fp = claws_fopen(src, "rb")) == NULL) {
 249                 FILE_OP_ERROR(src, "claws_fopen");
 250                 return -1;
 251         }
 252         if (is_file_exist(dest)) {
 253                 dest_bak = g_strconcat(dest, ".bak", NULL);
 254                 if (rename_force(dest, dest_bak) < 0) {
 255                         FILE_OP_ERROR(dest, "rename");
 256                         claws_fclose(src_fp);
 257                         g_free(dest_bak);
 258                         return -1;
 259                 }
 260         }
 261
 262         if ((dest_fp = claws_fopen(dest, "wb")) == NULL) {
 263                 FILE_OP_ERROR(dest, "claws_fopen");
 264                 claws_fclose(src_fp);
 265                 if (dest_bak) {
 266                         if (rename_force(dest_bak, dest) < 0)
 267                                 FILE_OP_ERROR(dest_bak, "rename");
 268                         g_free(dest_bak);
 269                 }
 270                 return -1;
 271         }
 272
 273         if (change_file_mode_rw(dest_fp, dest) < 0) {
 274                 FILE_OP_ERROR(dest, "chmod");
 275                 g_warning("can't change file mode: %s", dest);
 276         }
 277
 278         while ((n_read = claws_fread(buf, sizeof(gchar), sizeof(buf), src_fp)) > 0) {
 279                 if (n_read < sizeof(buf) && claws_ferror(src_fp))
 280                         break;
 281                 if (claws_fwrite(buf, 1, n_read, dest_fp) < n_read) {
 282                         g_warning("writing to %s failed.", dest);
 283                         claws_fclose(dest_fp);
 284                         claws_fclose(src_fp);
 285                         claws_unlink(dest);
 286                         if (dest_bak) {
 287                                 if (rename_force(dest_bak, dest) < 0)
 288                                         FILE_OP_ERROR(dest_bak, "rename");
 289                                 g_free(dest_bak);
 290                         }
 291                         return -1;
 292                 }
 293         }
 294
 295         if (claws_ferror(src_fp)) {
 296                 FILE_OP_ERROR(src, "claws_fread");
 297                 err = TRUE;
 298         }
 299         claws_fclose(src_fp);
 300         if (claws_safe_fclose(dest_fp) == EOF) {
 301                 FILE_OP_ERROR(dest, "claws_fclose");
 302                 err = TRUE;
 303         }
 304
 305         if (err) {
 306                 claws_unlink(dest);
 307                 if (dest_bak) {
 308                         if (rename_force(dest_bak, dest) < 0)
 309                                 FILE_OP_ERROR(dest_bak, "rename");
 310                         g_free(dest_bak);
 311                 }
 312                 return -1;
 313         }
 314
 315         if (keep_backup == FALSE && dest_bak)
 316                 claws_unlink(dest_bak);
 317
 318         g_free(dest_bak);
 319
 320         return 0;
 321 }
 322
 323 gint move_file(const gchar *src, const gchar *dest, gboolean overwrite)
 324 {
 325         if (overwrite == FALSE && is_file_exist(dest)) {
 326                 g_warning("move_file(): file %s already exists.", dest);
 327                 return -1;
 328         }
 329
 330         if (rename_force(src, dest) == 0) return 0;
 331
 332         if (EXDEV != errno) {
 333                 FILE_OP_ERROR(src, "rename");
 334                 return -1;
 335         }
 336
 337         if (copy_file(src, dest, FALSE) < 0) return -1;
 338
 339         claws_unlink(src);
 340
 341         return 0;
 342 }
 343
 344 gint copy_file_part_to_fp(FILE *fp, off_t offset, size_t length, FILE *dest_fp)
 345 {
 346         gint n_read;
 347         gint bytes_left, to_read;
 348         gchar buf[BUFSIZ];
 349
 350         if (fseek(fp, offset, SEEK_SET) < 0) {
 351                 perror("fseek");
 352                 return -1;
 353         }
 354
 355         bytes_left = length;
 356         to_read = MIN(bytes_left, sizeof(buf));
 357
 358         while ((n_read = claws_fread(buf, sizeof(gchar), to_read, fp)) > 0) {
 359                 if (n_read < to_read && claws_ferror(fp))
 360                         break;
 361                 if (claws_fwrite(buf, 1, n_read, dest_fp) < n_read) {
 362                         return -1;
 363                 }
 364                 bytes_left -= n_read;
 365                 if (bytes_left == 0)
 366                         break;
 367                 to_read = MIN(bytes_left, sizeof(buf));
 368         }
 369
 370         if (claws_ferror(fp)) {
 371                 perror("claws_fread");
 372                 return -1;
 373         }
 374
 375         return 0;
 376 }
 377
 378 gint copy_file_part(FILE *fp, off_t offset, size_t length, const gchar *dest)
 379 {
 380         FILE *dest_fp;
 381         gboolean err = FALSE;
 382
 383         if ((dest_fp = claws_fopen(dest, "wb")) == NULL) {
 384                 FILE_OP_ERROR(dest, "claws_fopen");
 385                 return -1;
 386         }
 387
 388         if (change_file_mode_rw(dest_fp, dest) < 0) {
 389                 FILE_OP_ERROR(dest, "chmod");
 390                 g_warning("can't change file mode: %s", dest);
 391         }
 392
 393         if (copy_file_part_to_fp(fp, offset, length, dest_fp) < 0)
 394                 err = TRUE;
 395
 396         if (claws_safe_fclose(dest_fp) == EOF) {
 397                 FILE_OP_ERROR(dest, "claws_fclose");
 398                 err = TRUE;
 399         }
 400
 401         if (err) {
 402                 g_warning("writing to %s failed.", dest);
 403                 claws_unlink(dest);
 404                 return -1;
 405         }
 406
 407         return 0;
 408 }
 409
 410 gint canonicalize_file(const gchar *src, const gchar *dest)
 411 {
 412         FILE *src_fp, *dest_fp;
 413         gchar buf[BUFFSIZE];
 414         gint len;
 415         gboolean err = FALSE;
 416         gboolean last_linebreak = FALSE;
 417
 418         if (src == NULL || dest == NULL)
 419                 return -1;
 420
 421         if ((src_fp = claws_fopen(src, "rb")) == NULL) {
 422                 FILE_OP_ERROR(src, "claws_fopen");
 423                 return -1;
 424         }
 425
 426         if ((dest_fp = claws_fopen(dest, "wb")) == NULL) {
 427                 FILE_OP_ERROR(dest, "claws_fopen");
 428                 claws_fclose(src_fp);
 429                 return -1;
 430         }
 431
 432         if (change_file_mode_rw(dest_fp, dest) < 0) {
 433                 FILE_OP_ERROR(dest, "chmod");
 434                 g_warning("can't change file mode: %s", dest);
 435         }
 436
 437         while (claws_fgets(buf, sizeof(buf), src_fp) != NULL) {
 438                 gint r = 0;
 439
 440                 len = strlen(buf);
 441                 if (len == 0) break;
 442                 last_linebreak = FALSE;
 443
 444                 if (buf[len - 1] != '\n') {
 445                         last_linebreak = TRUE;
 446                         r = claws_fputs(buf, dest_fp);
 447                 } else if (len > 1 && buf[len - 1] == '\n' && buf[len - 2] == '\r') {
 448                         r = claws_fputs(buf, dest_fp);
 449                 } else {
 450                         if (len > 1) {
 451                                 r = claws_fwrite(buf, 1, len - 1, dest_fp);
 452                                 if (r != (len -1))
 453                                         r = EOF;
 454                         }
 455                         if (r != EOF)
 456                                 r = claws_fputs("\r\n", dest_fp);
 457                 }
 458
 459                 if (r == EOF) {
 460                         g_warning("writing to %s failed.", dest);
 461                         claws_fclose(dest_fp);
 462                         claws_fclose(src_fp);
 463                         claws_unlink(dest);
 464                         return -1;
 465                 }
 466         }
 467
 468         if (last_linebreak == TRUE) {
 469                 if (claws_fputs("\r\n", dest_fp) == EOF)
 470                         err = TRUE;
 471         }
 472
 473         if (claws_ferror(src_fp)) {
 474                 FILE_OP_ERROR(src, "claws_fgets");
 475                 err = TRUE;
 476         }
 477         claws_fclose(src_fp);
 478         if (claws_safe_fclose(dest_fp) == EOF) {
 479                 FILE_OP_ERROR(dest, "claws_fclose");
 480                 err = TRUE;
 481         }
 482
 483         if (err) {
 484                 claws_unlink(dest);
 485                 return -1;
 486         }
 487
 488         return 0;
 489 }
 490
 491 gint canonicalize_file_replace(const gchar *file)
 492 {
 493         gchar *tmp_file;
 494
 495         tmp_file = get_tmp_file();
 496
 497         if (canonicalize_file(file, tmp_file) < 0) {
 498                 g_free(tmp_file);
 499                 return -1;
 500         }
 501
 502         if (move_file(tmp_file, file, TRUE) < 0) {
 503                 g_warning("can't replace file: %s", file);
 504                 claws_unlink(tmp_file);
 505                 g_free(tmp_file);
 506                 return -1;
 507         }
 508
 509         g_free(tmp_file);
 510         return 0;
 511 }
 512
 513
 514 gint str_write_to_file(const gchar *str, const gchar *file)
 515 {
 516         FILE *fp;
 517         size_t len;
 518
 519         cm_return_val_if_fail(str != NULL, -1);
 520         cm_return_val_if_fail(file != NULL, -1);
 521
 522         if ((fp = claws_fopen(file, "wb")) == NULL) {
 523                 FILE_OP_ERROR(file, "claws_fopen");
 524                 return -1;
 525         }
 526
 527         len = strlen(str);
 528         if (len == 0) {
 529                 claws_fclose(fp);
 530                 return 0;
 531         }
 532
 533         if (claws_fwrite(str, 1, len, fp) != len) {
 534                 FILE_OP_ERROR(file, "claws_fwrite");
 535                 claws_fclose(fp);
 536                 claws_unlink(file);
 537                 return -1;
 538         }
 539
 540         if (claws_safe_fclose(fp) == EOF) {
 541                 FILE_OP_ERROR(file, "claws_fclose");
 542                 claws_unlink(file);
 543                 return -1;
 544         }
 545
 546         return 0;
 547 }
 548
 549 static gchar *file_read_stream_to_str_full(FILE *fp, gboolean recode)
 550 {
 551         GByteArray *array;
 552         guchar buf[BUFSIZ];
 553         gint n_read;
 554         gchar *str;
 555
 556         cm_return_val_if_fail(fp != NULL, NULL);
 557
 558         array = g_byte_array_new();
 559
 560         while ((n_read = claws_fread(buf, sizeof(gchar), sizeof(buf), fp)) > 0) {
 561                 if (n_read < sizeof(buf) && claws_ferror(fp))
 562                         break;
 563                 g_byte_array_append(array, buf, n_read);
 564         }
 565
 566         if (claws_ferror(fp)) {
 567                 FILE_OP_ERROR("file stream", "claws_fread");
 568                 g_byte_array_free(array, TRUE);
 569                 return NULL;
 570         }
 571
 572         buf[0] = '\0';
 573         g_byte_array_append(array, buf, 1);
 574         str = (gchar *)array->data;
 575         g_byte_array_free(array, FALSE);
 576
 577         if (recode && !g_utf8_validate(str, -1, NULL)) {
 578                 const gchar *src_codeset, *dest_codeset;
 579                 gchar *tmp = NULL;
 580                 src_codeset = conv_get_locale_charset_str();
 581                 dest_codeset = CS_UTF_8;
 582                 tmp = conv_codeset_strdup(str, src_codeset, dest_codeset);
 583                 g_free(str);
 584                 str = tmp;
 585         }
 586
 587         return str;
 588 }
 589
 590 static gchar *file_read_to_str_full(const gchar *file, gboolean recode)
 591 {
 592         FILE *fp;
 593         gchar *str;
 594         GStatBuf s;
 595 #ifndef G_OS_WIN32
 596         gint fd, err;
 597         struct timeval timeout = {1, 0};
 598         fd_set fds;
 599         int fflags = 0;
 600 #endif
 601
 602         cm_return_val_if_fail(file != NULL, NULL);
 603
 604         if (g_stat(file, &s) != 0) {
 605                 FILE_OP_ERROR(file, "stat");
 606                 return NULL;
 607         }
 608         if (S_ISDIR(s.st_mode)) {
 609                 g_warning("%s: is a directory", file);
 610                 return NULL;
 611         }
 612
 613 #ifdef G_OS_WIN32
 614         fp = claws_fopen (file, "rb");
 615         if (fp == NULL) {
 616                 FILE_OP_ERROR(file, "open");
 617                 return NULL;
 618         }
 619 #else
 620         /* test whether the file is readable without blocking */
 621         fd = g_open(file, O_RDONLY | O_NONBLOCK, 0);
 622         if (fd == -1) {
 623                 FILE_OP_ERROR(file, "open");
 624                 return NULL;
 625         }
 626
 627         FD_ZERO(&fds);
 628         FD_SET(fd, &fds);
 629
 630         /* allow for one second */
 631         err = select(fd+1, &fds, NULL, NULL, &timeout);
 632         if (err <= 0 || !FD_ISSET(fd, &fds)) {
 633                 if (err < 0) {
 634                         FILE_OP_ERROR(file, "select");
 635                 } else {
 636                         g_warning("%s: doesn't seem readable", file);
 637                 }
 638                 close(fd);
 639                 return NULL;
 640         }
 641
 642         /* Now clear O_NONBLOCK */
 643         if ((fflags = fcntl(fd, F_GETFL)) < 0) {
 644                 FILE_OP_ERROR(file, "fcntl (F_GETFL)");
 645                 close(fd);
 646                 return NULL;
 647         }
 648         if (fcntl(fd, F_SETFL, (fflags & ~O_NONBLOCK)) < 0) {
 649                 FILE_OP_ERROR(file, "fcntl (F_SETFL)");
 650                 close(fd);
 651                 return NULL;
 652         }
 653
 654         /* get the FILE pointer */
 655         fp = claws_fdopen(fd, "rb");
 656
 657         if (fp == NULL) {
 658                 FILE_OP_ERROR(file, "claws_fdopen");
 659                 close(fd); /* if fp isn't NULL, we'll use claws_fclose instead! */
 660                 return NULL;
 661         }
 662 #endif
 663
 664         str = file_read_stream_to_str_full(fp, recode);
 665
 666         claws_fclose(fp);
 667
 668         return str;
 669 }
 670
 671 gchar *file_read_to_str(const gchar *file)
 672 {
 673         return file_read_to_str_full(file, TRUE);
 674 }
 675 gchar *file_read_stream_to_str(FILE *fp)
 676 {
 677         return file_read_stream_to_str_full(fp, TRUE);
 678 }
 679
 680 gchar *file_read_to_str_no_recode(const gchar *file)
 681 {
 682         return file_read_to_str_full(file, FALSE);
 683 }
 684 gchar *file_read_stream_to_str_no_recode(FILE *fp)
 685 {
 686         return file_read_stream_to_str_full(fp, FALSE);
 687 }
 688
 689 gint rename_force(const gchar *oldpath, const gchar *newpath)
 690 {
 691 #ifndef G_OS_UNIX
 692         if (!is_file_entry_exist(oldpath)) {
 693                 errno = ENOENT;
 694                 return -1;
 695         }
 696         if (is_file_exist(newpath)) {
 697                 if (claws_unlink(newpath) < 0)
 698                         FILE_OP_ERROR(newpath, "unlink");
 699         }
 700 #endif
 701         return g_rename(oldpath, newpath);
 702 }
 703
 704 gint copy_dir(const gchar *src, const gchar *dst)
 705 {
 706         GDir *dir;
 707         const gchar *name;
 708
 709         if ((dir = g_dir_open(src, 0, NULL)) == NULL) {
 710                 g_warning("failed to open directory: %s", src);
 711                 return -1;
 712         }
 713
 714         if (make_dir(dst) < 0)
 715                 return -1;
 716
 717         while ((name = g_dir_read_name(dir)) != NULL) {
 718                 gchar *old_file, *new_file;
 719                 old_file = g_strconcat(src, G_DIR_SEPARATOR_S, name, NULL);
 720                 new_file = g_strconcat(dst, G_DIR_SEPARATOR_S, name, NULL);
 721                 debug_print("copying: %s -> %s\n", old_file, new_file);
 722                 if (g_file_test(old_file, G_FILE_TEST_IS_REGULAR)) {
 723                         gint r = copy_file(old_file, new_file, TRUE);
 724                         if (r < 0) {
 725                                 g_dir_close(dir);
 726                                 return r;
 727                         }
 728                 }
 729 #ifndef G_OS_WIN32
 730                 /* Windows has no symlinks.  Or well, Vista seems to
 731                    have something like this but the semantics might be
 732                    different.  Thus we don't use it under Windows. */
 733                  else if (g_file_test(old_file, G_FILE_TEST_IS_SYMLINK)) {
 734                         GError *error = NULL;
 735                         gint r = 0;
 736                         gchar *target = g_file_read_link(old_file, &error);
 737                         if (target)
 738                                 r = symlink(target, new_file);
 739                         g_free(target);
 740                         if (r < 0) {
 741                                 g_dir_close(dir);
 742                                 return r;
 743                         }
 744                  }
 745 #endif /*G_OS_WIN32*/
 746                 else if (g_file_test(old_file, G_FILE_TEST_IS_DIR)) {
 747                         gint r = copy_dir(old_file, new_file);
 748                         if (r < 0) {
 749                                 g_dir_close(dir);
 750                                 return r;
 751                         }
 752                 }
 753         }
 754         g_dir_close(dir);
 755         return 0;
 756 }
 757
 758 gint change_file_mode_rw(FILE *fp, const gchar *file)
 759 {
 760 #if HAVE_FCHMOD
 761         return fchmod(fileno(fp), S_IRUSR|S_IWUSR);
 762 #else
 763         return g_chmod(file, S_IRUSR|S_IWUSR);
 764 #endif
 765 }
 766
 767 FILE *my_tmpfile(void)
 768 {
 769         const gchar suffix[] = ".XXXXXX";
 770         const gchar *tmpdir;
 771         guint tmplen;
 772         const gchar *progname;
 773         guint proglen;
 774         gchar *fname;
 775         gint fd;
 776         FILE *fp;
 777 #ifndef G_OS_WIN32
 778         gchar buf[2]="\0";
 779 #endif
 780
 781         tmpdir = get_tmp_dir();
 782         tmplen = strlen(tmpdir);
 783         progname = g_get_prgname();
 784         if (progname == NULL)
 785                 progname = "claws-mail";
 786         proglen = strlen(progname);
 787         Xalloca(fname, tmplen + 1 + proglen + sizeof(suffix),
 788                 return tmpfile());
 789
 790         memcpy(fname, tmpdir, tmplen);
 791         fname[tmplen] = G_DIR_SEPARATOR;
 792         memcpy(fname + tmplen + 1, progname, proglen);
 793         memcpy(fname + tmplen + 1 + proglen, suffix, sizeof(suffix));
 794
 795         fd = g_mkstemp(fname);
 796         if (fd < 0)
 797                 return tmpfile();
 798
 799 #ifndef G_OS_WIN32
 800         claws_unlink(fname);
 801
 802         /* verify that we can write in the file after unlinking */
 803         if (write(fd, buf, 1) < 0) {
 804                 close(fd);
 805                 return tmpfile();
 806         }
 807
 808 #endif
 809
 810         fp = claws_fdopen(fd, "w+b");
 811         if (!fp)
 812                 close(fd);
 813         else {
 814                 rewind(fp);
 815                 return fp;
 816         }
 817
 818         return tmpfile();
 819 }
 820
 821 FILE *my_tmpfile_with_len(size_t len)
 822 {
 823 #if HAVE_FMEMOPEN
 824         FILE *tmpfp = fmemopen(NULL, len, "w+b");
 825
 826         if (tmpfp == NULL) {
 827                 return my_tmpfile();
 828         }
 829
 830         return tmpfp;
 831 #else
 832         return my_tmpfile();
 833 #endif
 834 }
 835
 836 FILE *get_tmpfile_in_dir(const gchar *dir, gchar **filename)
 837 {
 838         int fd;
 839         *filename = g_strdup_printf("%s%cclaws.XXXXXX", dir, G_DIR_SEPARATOR);
 840         fd = g_mkstemp(*filename);
 841         if (fd < 0)
 842                 return NULL;
 843         return claws_fdopen(fd, "w+");
 844 }
 845
 846 FILE *str_open_as_stream(const gchar *str)
 847 {
 848         FILE *fp;
 849         size_t len;
 850
 851         cm_return_val_if_fail(str != NULL, NULL);
 852
 853         fp = my_tmpfile();
 854         if (!fp) {
 855                 FILE_OP_ERROR("str_open_as_stream", "my_tmpfile");
 856                 return NULL;
 857         }
 858
 859         len = strlen(str);
 860         if (len == 0) return fp;
 861
 862         if (claws_fwrite(str, 1, len, fp) != len) {
 863                 FILE_OP_ERROR("str_open_as_stream", "claws_fwrite");
 864                 claws_fclose(fp);
 865                 return NULL;
 866         }
 867
 868         rewind(fp);
 869         return fp;
 870 }
 871
 872 #endif