include/vlc_fs.h

   1 /*****************************************************************************
   2  * vlc_fs.h: File system helpers
   3  *****************************************************************************
   4  * Copyright © 2006-2010 Rémi Denis-Courmont
   5  *
   6  * This program 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  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14  * GNU 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 this program; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  19  *****************************************************************************/
  20
  21 #ifndef VLC_FS_H
  22 #define VLC_FS_H 1
  23
  24 #include <sys/types.h>
  25 #include <dirent.h>
  26
  27 struct stat;
  28 struct iovec;
  29
  30 #ifdef _WIN32
  31 # include <sys/stat.h>
  32 # ifndef stat
  33 #  define stat _stati64
  34 # endif
  35 # ifndef fstat
  36 #  define fstat _fstati64
  37 # endif
  38 # ifndef _MSC_VER
  39 #  undef lseek
  40 #  define lseek _lseeki64
  41 # endif
  42 #endif
  43
  44 #ifdef __ANDROID__
  45 # define lseek lseek64
  46 #endif
  47
  48
  49 /**
  50  * \defgroup os Operating system
  51  * @{
  52  * \defgroup file File system
  53  * @{
  54  *
  55  * \file
  56  * The functions in this file help with using low-level Unix-style file
  57  * descriptors, BSD sockets and directories. In general, they retain the
  58  * prototype and most semantics from their respective standard equivalents.
  59  * However, there are a few differences:
  60  *  - On Windows, file path arguments are expected in UTF-8 format.
  61  *    They are converted to UTF-16 internally, thus enabling access to paths
  62  *    outside of the local Windows ANSI code page.
  63  *  - On POSIX systems, file descriptors are created with the close-on-exec
  64  *    flag set (atomically where possible), so that they do not leak to
  65  *    child process after fork-and-exec.
  66  *  - vlc_scandir(), inspired by GNU scandir(), passes file names rather than
  67  *    dirent structure pointers to its callbacks.
  68  *  - vlc_accept() takes an extra boolean for nonblocking mode (compare with
  69  *    the flags parameter in POSIX.next accept4()).
  70  *  - Writing functions do not emit a SIGPIPE signal in case of broken pipe.
  71  *
  72  * \defgroup fd File descriptors
  73  * @{
  74  */
  75
  76 /**
  77  * Opens a system file handle.
  78  *
  79  * @param filename file path to open (with UTF-8 encoding)
  80  * @param flags open() flags, see the C library open() documentation
  81  * @return a file handle on success, -1 on error (see errno).
  82  * @note Contrary to standard open(), this function returns a file handle
  83  * with the close-on-exec flag preset.
  84  */
  85 VLC_API int vlc_open(const char *filename, int flags, ...) VLC_USED;
  86
  87 /**
  88  * Opens a system file handle relative to an existing directory handle.
  89  *
  90  * @param dir directory file descriptor
  91  * @param filename file path to open (with UTF-8 encoding)
  92  * @param flags open() flags, see the C library open() documentation
  93  * @return a file handle on success, -1 on error (see errno).
  94  * @note Contrary to standard open(), this function returns a file handle
  95  * with the close-on-exec flag preset.
  96  */
  97 VLC_API int vlc_openat(int fd, const char *filename, int flags, ...) VLC_USED;
  98
  99 VLC_API int vlc_mkstemp( char * );
 100
 101 /**
 102  * Duplicates a file descriptor. The new file descriptor has the close-on-exec
 103  * descriptor flag preset.
 104  * @return a new file descriptor, -1 (see errno)
 105  */
 106 VLC_API int vlc_dup(int) VLC_USED;
 107
 108 /**
 109  * Creates a pipe (see "man pipe" for further reference). The new file
 110  * descriptors have the close-on-exec flag preset.
 111  * @return 0 on success, -1 on error (see errno)
 112  */
 113 VLC_API int vlc_pipe(int [2]) VLC_USED;
 114
 115 /**
 116  * Creates an anonymous regular file descriptor, i.e. a descriptor for a
 117  * temporary file.
 118  *
 119  * The file is initially empty. The storage space is automatically reclaimed
 120  * when all file descriptors referencing it are closed.
 121  *
 122  * The new file descriptor has the close-on-exec flag preset.
 123  *
 124  * @return a file descriptor on success, -1 on error (see errno)
 125  */
 126 VLC_API int vlc_memfd(void) VLC_USED;
 127
 128 /**
 129  * Writes data to a file descriptor. Unlike write(), if EPIPE error occurs,
 130  * this function does not generate a SIGPIPE signal.
 131  * @note If the file descriptor is known to be neither a pipe/FIFO nor a
 132  * connection-oriented socket, the normal write() should be used.
 133  */
 134 VLC_API ssize_t vlc_write(int, const void *, size_t);
 135
 136 /**
 137  * Writes data from an iovec structure to a file descriptor. Unlike writev(),
 138  * if EPIPE error occurs, this function does not generate a SIGPIPE signal.
 139  */
 140 VLC_API ssize_t vlc_writev(int, const struct iovec *, int);
 141
 142 /**
 143  * Closes a file descriptor.
 144  *
 145  * This closes a file descriptor. If this is a last file descriptor for the
 146  * underlying open file, the file is closed too; the exact semantics depend
 147  * on the type of file.
 148  *
 149  * @note The file descriptor is always closed when the function returns, even
 150  * if the function returns an error. The sole exception is if the file
 151  * descriptor was not currently valid, and thus cannot be closed (errno will
 152  * then be set to EBADF).
 153  *
 154  * @param fd file descriptor
 155  * @return Normally, zero is returned.
 156  * If an I/O error is detected before or while closing, the function may return
 157  * -1. Such an error is unrecoverable since the descriptor is closed.
 158  *
 159  * A nul return value does not necessarily imply that all pending I/O
 160  * succeeded, since I/O might still occur asynchronously afterwards.
 161  */
 162 VLC_API int vlc_close(int fd);
 163
 164 /**
 165  * @}
 166  */
 167
 168 /**
 169  * Finds file/inode information - like stat().
 170  * @note As far as possible, fstat() should be used instead.
 171  *
 172  * @param filename UTF-8 file path
 173  */
 174 VLC_API int vlc_stat(const char *filename, struct stat *) VLC_USED;
 175
 176 /**
 177  * Finds file/inode information, as lstat().
 178  * Consider using fstat() instead, if possible.
 179  *
 180  * @param filename UTF-8 file path
 181  */
 182 VLC_API int vlc_lstat(const char *filename, struct stat *) VLC_USED;
 183
 184 /**
 185  * Removes a file.
 186  *
 187  * @param filename a UTF-8 string with the name of the file you want to delete.
 188  * @return A 0 return value indicates success. A -1 return value indicates an
 189  *        error, and an error code is stored in errno
 190  */
 191 VLC_API int vlc_unlink(const char *filename);
 192
 193 /**
 194  * Moves a file atomically. This only works within a single file system.
 195  *
 196  * @param oldpath path to the file before the move
 197  * @param newpath intended path to the file after the move
 198  * @return A 0 return value indicates success. A -1 return value indicates an
 199  *        error, and an error code is stored in errno
 200  */
 201 VLC_API int vlc_rename(const char *oldpath, const char *newpath);
 202
 203 VLC_API FILE * vlc_fopen( const char *filename, const char *mode ) VLC_USED;
 204
 205 /**
 206  * \defgroup dir Directories
 207  * @{
 208  */
 209
 210 /**
 211  * Opens a DIR pointer.
 212  *
 213  * @param dirname UTF-8 representation of the directory name
 214  * @return a pointer to the DIR struct, or NULL in case of error.
 215  * Release with standard closedir().
 216  */
 217 VLC_API DIR *vlc_opendir(const char *dirname) VLC_USED;
 218
 219 /**
 220  * Reads the next file name from an open directory.
 221  *
 222  * @param dir directory handle as returned by vlc_opendir()
 223  *            (must not be used by another thread concurrently)
 224  *
 225  * @return a UTF-8 string of the directory entry. The string is valid until
 226  * the next call to vlc_readdir() or closedir() on the handle.
 227  * If there are no more entries in the directory, NULL is returned.
 228  * If an error occurs, errno is set and NULL is returned.
 229  */
 230 VLC_API const char *vlc_readdir(DIR *dir) VLC_USED;
 231
 232 VLC_API int vlc_loaddir( DIR *dir, char ***namelist, int (*select)( const char * ), int (*compar)( const char **, const char ** ) );
 233 VLC_API int vlc_scandir( const char *dirname, char ***namelist, int (*select)( const char * ), int (*compar)( const char **, const char ** ) );
 234
 235 /**
 236  * Creates a directory.
 237  *
 238  * @param dirname a UTF-8 string with the name of the directory that you
 239  *        want to create.
 240  * @param mode directory permissions
 241  * @return 0 on success, -1 on error (see errno).
 242  */
 243 VLC_API int vlc_mkdir(const char *dirname, mode_t mode);
 244
 245 /**
 246  * Determines the current working directory.
 247  *
 248  * @return the current working directory (must be free()'d)
 249  *         or NULL on error
 250  */
 251 VLC_API char *vlc_getcwd(void) VLC_USED;
 252
 253 /** @} */
 254 /** @} */
 255
 256 #if defined( _WIN32 )
 257 typedef struct vlc_DIR
 258 {
 259     _WDIR *wdir; /* MUST be first, see <vlc_fs.h> */
 260     char *entry;
 261     union
 262     {
 263         DWORD drives;
 264         bool insert_dot_dot;
 265     } u;
 266 } vlc_DIR;
 267
 268 static inline int vlc_closedir( DIR *dir )
 269 {
 270     vlc_DIR *vdir = (vlc_DIR *)dir;
 271     _WDIR *wdir = vdir->wdir;
 272
 273     free( vdir->entry );
 274     free( vdir );
 275     return (wdir != NULL) ? _wclosedir( wdir ) : 0;
 276 }
 277 # undef closedir
 278 # define closedir vlc_closedir
 279
 280 static inline void vlc_rewinddir( DIR *dir )
 281 {
 282     _WDIR *wdir = *(_WDIR **)dir;
 283
 284     _wrewinddir( wdir );
 285 }
 286 # undef rewinddir
 287 # define rewinddir vlc_rewinddir
 288 #endif
 289
 290 #ifdef __ANDROID__
 291 # define lseek lseek64
 292 #endif
 293
 294 #endif