src/util/file.c

   1 /** File utilities
   2  * @file */
   3
   4 #ifdef HAVE_CONFIG_H
   5 #include "config.h"
   6 #endif
   7
   8 #include <ctype.h>
   9 #include <errno.h>
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <string.h>
  13 #include <sys/types.h>
  14 #include <sys/stat.h> /* OS/2 needs this after sys/types.h */
  15 #ifdef HAVE_DIRENT_H
  16 #include <dirent.h> /* OS/2 needs this after sys/types.h */
  17 #endif
  18 #ifdef HAVE_FCNTL_H
  19 #include <fcntl.h> /* OS/2 needs this after sys/types.h */
  20 #endif
  21 #ifdef HAVE_PWD_H
  22 #include <pwd.h>
  23 #endif
  24 #ifdef HAVE_UNISTD_H
  25 #include <unistd.h>
  26 #endif
  27
  28 #ifdef TIME_WITH_SYS_TIME
  29 #ifdef HAVE_SYS_TIME_H
  30 #include <sys/time.h>
  31 #endif
  32 #ifdef HAVE_TIME_H
  33 #include <time.h>
  34 #endif
  35 #else
  36 #if defined(TM_IN_SYS_TIME) && defined(HAVE_SYS_TIME_H)
  37 #include <sys/time.h>
  38 #elif defined(HAVE_TIME_H)
  39 #include <time.h>
  40 #endif
  41 #endif
  42
  43 #include "elinks.h"
  44
  45 #include "osdep/osdep.h"
  46 #include "util/conv.h"
  47 #include "util/error.h"
  48 #include "util/file.h"
  49 #include "util/memory.h"
  50 #include "util/string.h"
  51
  52
  53 /* Not that these two would be so useful for portability (they are ANSI C) but
  54  * they encapsulate the lowlevel stuff (need for <unistd.h>) nicely. */
  55
  56 int
  57 file_exists(const unsigned char *filename)
  58 {
  59 #ifdef HAVE_ACCESS
  60         return access(filename, F_OK) >= 0;
  61 #else
  62         struct stat buf;
  63
  64         return stat(filename, &buf) >= 0;
  65 #endif
  66 }
  67
  68 int
  69 file_can_read(const unsigned char *filename)
  70 {
  71 #ifdef HAVE_ACCESS
  72         return access(filename, R_OK) >= 0;
  73 #else
  74         FILE *f = fopen(filename, "rb");
  75         int ok = !!f;
  76
  77         if (f) fclose(f);
  78         return ok;
  79 #endif
  80 }
  81
  82 int
  83 file_is_dir(const unsigned char *filename)
  84 {
  85         struct stat st;
  86
  87         if (stat(filename, &st))
  88                 return 0;
  89
  90         return S_ISDIR(st.st_mode);
  91 }
  92
  93 unsigned char *
  94 get_filename_position(unsigned char *filename)
  95 {
  96         unsigned char *pos;
  97
  98         assert(filename);
  99         if_assert_failed return NULL;
 100
 101         for (pos = filename; *pos; pos++)
 102                 if (dir_sep(*pos)) filename = pos + 1;
 103
 104         return filename;
 105 }
 106
 107 unsigned char *
 108 expand_tilde(unsigned char *filename)
 109 {
 110         struct string file;
 111
 112         if (!init_string(&file)) return NULL;
 113
 114         if (filename[0] == '~') {
 115                 if (!filename[1] || dir_sep(filename[1])) {
 116                         unsigned char *home = getenv("HOME");
 117
 118                         if (home) {
 119                                 add_to_string(&file, home);
 120                                 filename++;
 121                         }
 122 #ifdef HAVE_GETPWNAM
 123                 } else {
 124                         struct passwd *passwd = NULL;
 125                         unsigned char *user = filename + 1;
 126                         int userlen = 0;
 127
 128                         while (user[userlen] && !dir_sep(user[userlen]))
 129                                 userlen++;
 130
 131                         user = memacpy(user, userlen);
 132                         if (user) {
 133                                 passwd = getpwnam(user);
 134                                 mem_free(user);
 135                         }
 136
 137                         if (passwd && passwd->pw_dir) {
 138                                 add_to_string(&file, passwd->pw_dir);
 139                                 filename += 1 + userlen;
 140                         }
 141 #endif
 142                 }
 143         }
 144
 145         add_to_string(&file, filename);
 146
 147         return file.source;
 148 }
 149
 150 unsigned char *
 151 get_unique_name(unsigned char *fileprefix)
 152 {
 153         unsigned char *file = fileprefix;
 154         int fileprefixlen = strlen(fileprefix);
 155         int memtrigger = 1;
 156         int suffix = 1;
 157         int digits = 0;
 158
 159         while (file_exists(file)) {
 160                 if (!(suffix < memtrigger)) {
 161                         if (suffix >= 10000)
 162                                 INTERNAL("Too big suffix in get_unique_name().");
 163                         memtrigger *= 10;
 164                         digits++;
 165
 166                         if (file != fileprefix) mem_free(file);
 167                         file = mem_alloc(fileprefixlen + 2 + digits);
 168                         if (!file) return NULL;
 169
 170                         memcpy(file, fileprefix, fileprefixlen);
 171                         file[fileprefixlen] = '.';
 172                 }
 173
 174                 longcat(&file[fileprefixlen + 1], NULL, suffix, digits + 1, 0);
 175                 suffix++;
 176         }
 177
 178         return file;
 179 }
 180
 181 unsigned char *
 182 get_tempdir_filename(unsigned char *name)
 183 {
 184         unsigned char *tmpdir = getenv("TMPDIR");
 185
 186         if (!tmpdir || !*tmpdir) tmpdir = getenv("TMP");
 187         if (!tmpdir || !*tmpdir) tmpdir = getenv("TEMPDIR");
 188         if (!tmpdir || !*tmpdir) tmpdir = getenv("TEMP");
 189         if (!tmpdir || !*tmpdir) tmpdir = "/tmp";
 190
 191         return straconcat(tmpdir, "/", name, (unsigned char *) NULL);
 192 }
 193
 194 unsigned char *
 195 file_read_line(unsigned char *line, size_t *size, FILE *file, int *lineno)
 196 {
 197         size_t offset = 0;
 198
 199         if (!line) {
 200                 line = mem_alloc(MAX_STR_LEN);
 201                 if (!line)
 202                         return NULL;
 203
 204                 *size = MAX_STR_LEN;
 205         }
 206
 207         while (fgets(line + offset, *size - offset, file)) {
 208                 unsigned char *linepos = strchr((const char *)(line + offset), '\n');
 209
 210                 if (!linepos) {
 211                         /* Test if the line buffer should be increase because
 212                          * it was continued and could not fit. */
 213                         unsigned char *newline;
 214                         int next = getc(file);
 215
 216                         if (next == EOF) {
 217                                 /* We are on the last line. */
 218                                 (*lineno)++;
 219                                 return line;
 220                         }
 221
 222                         /* Undo our dammage */
 223                         ungetc(next, file);
 224                         offset = *size - 1;
 225                         *size += MAX_STR_LEN;
 226
 227                         newline = mem_realloc(line, *size);
 228                         if (!newline)
 229                                 break;
 230                         line = newline;
 231                         continue;
 232                 }
 233
 234                 /* A whole line was read. Fetch next into the buffer if
 235                  * the line is 'continued'. */
 236                 (*lineno)++;
 237
 238                 while (line < linepos && isspace(*linepos))
 239                         linepos--;
 240
 241                 if (*linepos != '\\') {
 242                         *(linepos + 1) = '\0';
 243                         return line;
 244                 }
 245                 offset = linepos - line - 1;
 246         }
 247
 248         mem_free_if(line);
 249         return NULL;
 250 }
 251
 252
 253 /* Some mkstemp() implementations do not set safe permissions,
 254  * so it may result in temporary files readable by all users.
 255  * This may be a problem when textarea fields are edited through
 256  * an external editor (see src/viewer/text/textarea.c).
 257  *
 258  * From 2001-12-23 mkstemp(3) gnu man page:
 259  *
 260  * ...
 261  * The file is then created with mode read/write and permissions 0666
 262  * (glibc  2.0.6 and  earlier), 0600 (glibc 2.0.7 and later).
 263  * ...
 264  *
 265  * NOTES:
 266  * The old behaviour (creating a file with mode 0666) may be a security
 267  * risk, especially since other Unix flavours use 0600, and somebody
 268  * might overlook this detail when porting programs.
 269  * More generally, the POSIX specification does not say anything
 270  * about file modes, so the application should make sure its umask is
 271  * set appropriately before calling mkstemp.
 272  */
 273 int
 274 safe_mkstemp(unsigned char *template_)
 275 {
 276 #ifndef CONFIG_OS_WIN32
 277         mode_t saved_mask = umask(S_IXUSR | S_IRWXG | S_IRWXO);
 278 #endif
 279         int fd = mkstemp(template_);
 280 #ifndef CONFIG_OS_WIN32
 281         umask(saved_mask);
 282 #endif
 283         return fd;
 284 }
 285
 286 /* comparison function for qsort() */
 287 int
 288 compare_dir_entries(const void *v1, const void *v2)
 289 {
 290         const struct directory_entry *d1 = v1, *d2 = v2;
 291
 292         if (d1->name[0] == '.' && d1->name[1] == '.' && !d1->name[2]) return -1;
 293         if (d2->name[0] == '.' && d2->name[1] == '.' && !d2->name[2]) return 1;
 294         if (d1->attrib[0] == 'd' && d2->attrib[0] != 'd') return -1;
 295         if (d1->attrib[0] != 'd' && d2->attrib[0] == 'd') return 1;
 296         return strcmp(d1->name, d2->name);
 297 }
 298
 299
 300 /** This function decides whether a file should be shown in directory
 301  * listing or not. @returns according boolean value. */
 302 static inline int
 303 file_visible(unsigned char *name, int get_hidden_files, int is_root_directory)
 304 {
 305         /* Always show everything not beginning with a dot. */
 306         if (name[0] != '.')
 307                 return 1;
 308
 309         /* Always hide the "." directory. */
 310         if (name[1] == '\0')
 311                 return 0;
 312
 313         /* Always show the ".." directory (but for root directory). */
 314         if (name[1] == '.' && name[2] == '\0')
 315                 return !is_root_directory;
 316
 317         /* Others like ".x" or "..foo" are shown if get_hidden_files
 318          * == 1. */
 319         return get_hidden_files;
 320 }
 321
 322 /** First information such as permissions is gathered for each directory entry.
 323  * All entries are then sorted. */
 324 struct directory_entry *
 325 get_directory_entries(unsigned char *dirname, int get_hidden)
 326 {
 327         struct directory_entry *entries = NULL;
 328         DIR *directory;
 329         int size = 0;
 330         struct dirent *entry;
 331         int is_root_directory = dirname[0] == '/' && !dirname[1];
 332
 333         directory = opendir(dirname);
 334         if (!directory) return NULL;
 335
 336         while ((entry = readdir(directory))) {
 337                 struct stat st, *stp;
 338                 struct directory_entry *new_entries;
 339                 unsigned char *name;
 340                 struct string attrib;
 341
 342                 if (!file_visible(entry->d_name, get_hidden, is_root_directory))
 343                         continue;
 344
 345                 new_entries = mem_realloc(entries, (size + 2) * sizeof(*new_entries));
 346                 if (!new_entries) continue;
 347                 entries = new_entries;
 348
 349                 /* We allocate the full path because it is used in a few places
 350                  * which means less allocation although a bit more short term
 351                  * memory usage. */
 352                 name = straconcat(dirname, entry->d_name,
 353                                   (unsigned char *) NULL);
 354                 if (!name) continue;
 355
 356                 if (!init_string(&attrib)) {
 357                         mem_free(name);
 358                         continue;
 359                 }
 360
 361 #ifdef FS_UNIX_SOFTLINKS
 362                 stp = (lstat(name, &st)) ? NULL : &st;
 363 #else
 364                 stp = (stat(name, &st)) ? NULL : &st;
 365 #endif
 366
 367                 stat_type(&attrib, stp);
 368                 stat_mode(&attrib, stp);
 369                 stat_links(&attrib, stp);
 370                 stat_user(&attrib, stp);
 371                 stat_group(&attrib, stp);
 372                 stat_size(&attrib, stp);
 373                 stat_date(&attrib, stp);
 374
 375                 entries[size].name = name;
 376                 entries[size].attrib = attrib.source;
 377                 size++;
 378         }
 379
 380         closedir(directory);
 381
 382         if (!size) {
 383                 /* We may have allocated space for entries but added none. */
 384                 mem_free_if(entries);
 385                 return NULL;
 386         }
 387
 388         qsort(entries, size, sizeof(*entries), compare_dir_entries);
 389
 390         memset(&entries[size], 0, sizeof(*entries));
 391
 392         return entries;
 393 }
 394
 395 /** Recursively create directories in @a path. The last element in the path is
 396  * taken to be a filename, and simply ignored */
 397 int
 398 mkalldirs(const unsigned char *path)
 399 {
 400         int pos, len, ret = 0;
 401         unsigned char *p;
 402
 403         if (!*path) return -1;
 404
 405         /* Make a copy of path, to be able to write to it.  Otherwise, the
 406          * function is unsafe if called with a read-only char *argument.  */
 407         len = strlen(path) + 1;
 408         p = fmem_alloc(len);
 409         if (!p) return -1;
 410         memcpy(p, path, len);
 411
 412         for (pos = 1; p[pos]; pos++) {
 413                 unsigned char separator = p[pos];
 414
 415                 if (!dir_sep(separator))
 416                         continue;
 417
 418                 p[pos] = 0;
 419
 420                 ret = mkdir(p, S_IRWXU);
 421
 422                 p[pos] = separator;
 423
 424                 if (ret < 0) {
 425                         if (errno != EEXIST) break;
 426                         ret = 0;
 427                 }
 428         }
 429
 430         fmem_free(p);
 431         return ret;
 432 }