src/text/filesystem.c

   1 /*****************************************************************************
   2  * filesystem.c: Common file system helpers
   3  *****************************************************************************
   4  * Copyright (C) 2005-2006 VLC authors and VideoLAN
   5  * Copyright © 2005-2008 Rémi Denis-Courmont
   6  *
   7  * Authors: Rémi Denis-Courmont <rem # videolan.org>
   8  *
   9  * This program is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU Lesser General Public License as published by
  11  * the Free Software Foundation; either version 2.1 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  17  * GNU Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public License
  20  * along with this program; if not, write to the Free Software Foundation,
  21  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  22  *****************************************************************************/
  23
  24 /*****************************************************************************
  25  * Preamble
  26  *****************************************************************************/
  27 #ifdef HAVE_CONFIG_H
  28 # include "config.h"
  29 #endif
  30
  31 #include <vlc_common.h>
  32 #include <vlc_fs.h>
  33 #include <vlc_rand.h>
  34
  35 #include <assert.h>
  36
  37 #include <stdio.h>
  38 #include <errno.h>
  39 #include <sys/types.h>
  40 #include <fcntl.h>
  41 #ifdef HAVE_UNISTD_H
  42 # include <unistd.h>
  43 #endif
  44
  45 /**
  46  * Opens a FILE pointer.
  47  * @param filename file path, using UTF-8 encoding
  48  * @param mode fopen file open mode
  49  * @return NULL on error, an open FILE pointer on success.
  50  */
  51 FILE *vlc_fopen (const char *filename, const char *mode)
  52 {
  53     int rwflags = 0, oflags = 0;
  54
  55     for (const char *ptr = mode; *ptr; ptr++)
  56     {
  57         switch (*ptr)
  58         {
  59             case 'r':
  60                 rwflags = O_RDONLY;
  61                 break;
  62
  63             case 'a':
  64                 rwflags = O_WRONLY;
  65                 oflags |= O_CREAT | O_APPEND;
  66                 break;
  67
  68             case 'w':
  69                 rwflags = O_WRONLY;
  70                 oflags |= O_CREAT | O_TRUNC;
  71                 break;
  72
  73             case 'x':
  74                 oflags |= O_EXCL;
  75                 break;
  76
  77             case '+':
  78                 rwflags = O_RDWR;
  79                 break;
  80
  81 #ifdef O_BINARY
  82             case 'b':
  83                 oflags = (oflags & ~O_TEXT) | O_BINARY;
  84                 break;
  85
  86             case 't':
  87                 oflags = (oflags & ~O_BINARY) | O_TEXT;
  88                 break;
  89 #endif
  90         }
  91     }
  92
  93     int fd = vlc_open (filename, rwflags | oflags, 0666);
  94     if (fd == -1)
  95         return NULL;
  96
  97     FILE *stream = fdopen (fd, mode);
  98     if (stream == NULL)
  99         close (fd);
 100
 101     return stream;
 102 }
 103
 104
 105 static int dummy_select( const char *str )
 106 {
 107     (void)str;
 108     return 1;
 109 }
 110
 111 /**
 112  * Does the same as vlc_scandir(), but takes an open directory pointer
 113  * instead of a directory path.
 114  */
 115 int vlc_loaddir( DIR *dir, char ***namelist,
 116                   int (*select)( const char * ),
 117                   int (*compar)( const char **, const char ** ) )
 118 {
 119     assert (dir);
 120
 121     if (select == NULL)
 122         select = dummy_select;
 123
 124     char **tab = NULL;
 125     unsigned num = 0;
 126
 127     rewinddir (dir);
 128
 129     for (unsigned size = 0;;)
 130     {
 131         errno = 0;
 132         char *entry = vlc_readdir (dir);
 133         if (entry == NULL)
 134         {
 135             if (errno)
 136                 goto error;
 137             break;
 138         }
 139
 140         if (!select (entry))
 141         {
 142             free (entry);
 143             continue;
 144         }
 145
 146         if (num >= size)
 147         {
 148             size = size ? (2 * size) : 16;
 149             char **newtab = realloc (tab, sizeof (*tab) * (size));
 150
 151             if (unlikely(newtab == NULL))
 152             {
 153                 free (entry);
 154                 goto error;
 155             }
 156             tab = newtab;
 157         }
 158
 159         tab[num++] = entry;
 160     }
 161
 162     if (compar != NULL)
 163         qsort (tab, num, sizeof (*tab),
 164                (int (*)( const void *, const void *))compar);
 165     *namelist = tab;
 166     return num;
 167
 168 error:
 169     for (unsigned i = 0; i < num; i++)
 170         free (tab[i]);
 171     free (tab);
 172     return -1;
 173 }
 174
 175 /**
 176  * Selects file entries from a directory, as GNU C scandir().
 177  *
 178  * @param dirname UTF-8 diretory path
 179  * @param pointer [OUT] pointer set, on successful completion, to the address
 180  * of a table of UTF-8 filenames. All filenames must be freed with free().
 181  * The table itself must be freed with free() as well.
 182  *
 183  * @return How many file names were selected (possibly 0),
 184  * or -1 in case of error.
 185  */
 186 int vlc_scandir( const char *dirname, char ***namelist,
 187                   int (*select)( const char * ),
 188                   int (*compar)( const char **, const char ** ) )
 189 {
 190     DIR *dir = vlc_opendir (dirname);
 191     int val = -1;
 192
 193     if (dir != NULL)
 194     {
 195         val = vlc_loaddir (dir, namelist, select, compar);
 196         closedir (dir);
 197     }
 198     return val;
 199 }
 200
 201 int vlc_mkstemp( char *template )
 202 {
 203     static const char digits[] = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
 204     static const int i_digits = sizeof(digits)/sizeof(*digits) - 1;
 205
 206     /* */
 207     assert( template );
 208
 209     /* Check template validity */
 210     const size_t i_length = strlen( template );
 211     char *psz_rand = &template[i_length-6];
 212
 213     if( i_length < 6 || strcmp( psz_rand, "XXXXXX" ) )
 214     {
 215         errno = EINVAL;
 216         return -1;
 217     }
 218
 219     /* */
 220     for( int i = 0; i < 256; i++ )
 221     {
 222         /* Create a pseudo random file name */
 223         uint8_t pi_rand[6];
 224
 225         vlc_rand_bytes( pi_rand, sizeof(pi_rand) );
 226         for( int j = 0; j < 6; j++ )
 227             psz_rand[j] = digits[pi_rand[j] % i_digits];
 228
 229         /* */
 230         int fd = vlc_open( template, O_CREAT | O_EXCL | O_RDWR, 0600 );
 231         if( fd >= 0 )
 232             return fd;
 233         if( errno != EEXIST )
 234             return -1;
 235     }
 236
 237     errno = EEXIST;
 238     return -1;
 239 }