include/fcntl.h

   1 /* Copyright (C) 1991,1992,1994-2001,2003,2004,2005,2006,2007, 2009
   2         Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library 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 GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 /*
  20  *      POSIX Standard: 6.5 File Control Operations     <fcntl.h>
  21  */
  22
  23 #ifndef _FCNTL_H
  24 #define _FCNTL_H        1
  25
  26 #include <features.h>
  27
  28 /* This must be early so <bits/fcntl.h> can define types winningly.  */
  29 __BEGIN_DECLS
  30
  31 /* Get the definitions of O_*, F_*, FD_*: all the
  32    numbers and flag bits for `open', `fcntl', et al.  */
  33 #include <bits/fcntl.h>
  34
  35 /* For XPG all symbols from <sys/stat.h> should also be available.  */
  36 #ifdef __USE_XOPEN
  37 # include <sys/stat.h>
  38 #endif
  39
  40 #ifdef  __USE_MISC
  41 # ifndef R_OK                   /* Verbatim from <unistd.h>.  Ugh.  */
  42 /* Values for the second argument to access.
  43    These may be OR'd together.  */
  44 #  define R_OK  4               /* Test for read permission.  */
  45 #  define W_OK  2               /* Test for write permission.  */
  46 #  define X_OK  1               /* Test for execute permission.  */
  47 #  define F_OK  0               /* Test for existence.  */
  48 # endif
  49 #endif /* Use misc.  */
  50
  51 /* XPG wants the following symbols.  */
  52 #ifdef __USE_XOPEN              /* <stdio.h> has the same definitions.  */
  53 # define SEEK_SET       0       /* Seek from beginning of file.  */
  54 # define SEEK_CUR       1       /* Seek from current position.  */
  55 # define SEEK_END       2       /* Seek from end of file.  */
  56 #endif  /* XPG */
  57
  58 #ifdef __USE_ATFILE
  59 # define AT_FDCWD               -100    /* Special value used to indicate
  60                                            the *at functions should use the
  61                                            current working directory. */
  62 # define AT_SYMLINK_NOFOLLOW    0x100   /* Do not follow symbolic links.  */
  63 # define AT_REMOVEDIR           0x200   /* Remove directory instead of
  64                                            unlinking file.  */
  65 # define AT_SYMLINK_FOLLOW      0x400   /* Follow symbolic links.  */
  66 # ifdef __USE_GNU
  67 #  define AT_NO_AUTOMOUNT       0x800   /* Suppress terminal automount
  68                                            traversal.  */
  69 #  define AT_EMPTY_PATH         0x1000  /* Allow empty relative pathname.  */
  70 #  define AT_STATX_SYNC_TYPE    0x6000
  71 #  define AT_STATX_SYNC_AS_STAT 0x0000
  72 #  define AT_STATX_FORCE_SYNC   0x2000
  73 #  define AT_STATX_DONT_SYNC    0x4000
  74 #  define AT_RECURSIVE          0x8000  /* Apply to the entire subtree.  */
  75 # endif
  76 # define AT_EACCESS             0x200   /* Test access permitted for
  77                                            effective IDs, not real IDs.  */
  78 #endif
  79
  80 /* Do the file control operation described by CMD on FD.
  81    The remaining arguments are interpreted depending on CMD.
  82
  83    This function is a cancellation point and therefore not marked with
  84    __THROW.  */
  85 #if !defined(__USE_FILE_OFFSET64) || defined(__LP64__)
  86 extern int fcntl (int __fd, int __cmd, ...);
  87 # ifdef _LIBC
  88 extern int __fcntl_nocancel(int, int, long) attribute_hidden;
  89 libc_hidden_proto(fcntl)
  90 # endif
  91 #else
  92 # ifdef __REDIRECT
  93 extern int __REDIRECT (fcntl, (int __fd, int __cmd, ...), fcntl64);
  94 # else
  95 #  define fcntl fcntl64
  96 # endif
  97 #endif
  98 #if defined(__USE_LARGEFILE64) && !defined(__LP64__)
  99 extern int fcntl64 (int __fd, int __cmd, ...);
 100 # ifdef _LIBC
 101 extern int __fcntl64_nocancel(int, int, long) attribute_hidden;
 102 libc_hidden_proto(fcntl64)
 103 # endif
 104 #endif
 105
 106 /* Open FILE and return a new file descriptor for it, or -1 on error.
 107    OFLAG determines the type of access used.  If O_CREAT or O_TMPFILE
 108    is on OFLAG, the third argument is taken as a `mode_t', the mode of
 109    the created file.
 110
 111    This function is a cancellation point and therefore not marked with
 112    __THROW.  */
 113 #ifndef __USE_FILE_OFFSET64
 114 extern int open (const char *__file, int __oflag, ...) __nonnull ((1));
 115 libc_hidden_proto(open)
 116 # ifdef _LIBC
 117 extern int __open2_nocancel(const char *, int) __nonnull ((1)) attribute_hidden;
 118 extern int __open_nocancel(const char *, int, mode_t) __nonnull ((1)) attribute_hidden;
 119 # endif
 120 #else
 121 # ifdef __REDIRECT
 122 extern int __REDIRECT (open, (const char *__file, int __oflag, ...), open64)
 123      __nonnull ((1));
 124 # else
 125 #  define open open64
 126 # endif
 127 #endif
 128 #ifdef __USE_LARGEFILE64
 129 extern int open64 (const char *__file, int __oflag, ...) __nonnull ((1));
 130 libc_hidden_proto(open64)
 131 #endif
 132
 133 #ifdef __USE_ATFILE
 134 /* Similar to `open' but a relative path name is interpreted relative to
 135    the directory for which FD is a descriptor.
 136
 137    NOTE: some other `openat' implementation support additional functionality
 138    through this interface, especially using the O_XATTR flag.  This is not
 139    yet supported here.
 140
 141    This function is a cancellation point and therefore not marked with
 142    __THROW.  */
 143 # ifndef __USE_FILE_OFFSET64
 144 extern int openat (int __fd, const char *__file, int __oflag, ...)
 145      __nonnull ((2));
 146 libc_hidden_proto(openat)
 147 # else
 148 #  ifdef __REDIRECT
 149 extern int __REDIRECT (openat, (int __fd, const char *__file, int __oflag,
 150                                 ...), openat64) __nonnull ((2));
 151 #  else
 152 #   define openat openat64
 153 #  endif
 154 # endif
 155
 156 extern int openat64 (int __fd, const char *__file, int __oflag, ...)
 157      __nonnull ((2));
 158 #endif
 159
 160 /* Create and open FILE, with mode MODE.  This takes an `int' MODE
 161    argument because that is what `mode_t' will be widened to.
 162
 163    This function is a cancellation point and therefore not marked with
 164    __THROW.  */
 165 #ifndef __USE_FILE_OFFSET64
 166 extern int creat (const char *__file, __mode_t __mode) __nonnull ((1));
 167 #else
 168 # ifdef __REDIRECT
 169 extern int __REDIRECT (creat, (const char *__file, __mode_t __mode),
 170                        creat64) __nonnull ((1));
 171 # else
 172 #  define creat creat64
 173 # endif
 174 #endif
 175 #ifdef __USE_LARGEFILE64
 176 extern int creat64 (const char *__file, __mode_t __mode) __nonnull ((1));
 177 #endif
 178
 179 #if !defined F_LOCK && (defined __USE_MISC || (defined __USE_XOPEN_EXTENDED \
 180                                                && !defined __USE_POSIX))
 181 /* NOTE: These declarations also appear in <unistd.h>; be sure to keep both
 182    files consistent.  Some systems have them there and some here, and some
 183    software depends on the macros being defined without including both.  */
 184
 185 /* `lockf' is a simpler interface to the locking facilities of `fcntl'.
 186    LEN is always relative to the current file position.
 187    The CMD argument is one of the following.  */
 188
 189 # define F_ULOCK 0      /* Unlock a previously locked region.  */
 190 # define F_LOCK  1      /* Lock a region for exclusive use.  */
 191 # define F_TLOCK 2      /* Test and lock a region for exclusive use.  */
 192 # define F_TEST  3      /* Test a region for other processes locks.  */
 193
 194 # ifndef __USE_FILE_OFFSET64
 195 extern int lockf (int __fd, int __cmd, __off_t __len);
 196 libc_hidden_proto(lockf)
 197 # else
 198 #  ifdef __REDIRECT
 199 extern int __REDIRECT (lockf, (int __fd, int __cmd, __off64_t __len), lockf64);
 200 #  else
 201 #   define lockf lockf64
 202 #  endif
 203 # endif
 204 # ifdef __USE_LARGEFILE64
 205 extern int lockf64 (int __fd, int __cmd, __off64_t __len);
 206 # endif
 207 #endif
 208
 209 #if defined __USE_XOPEN2K && defined __UCLIBC_HAS_ADVANCED_REALTIME__
 210 /* Advice the system about the expected behaviour of the application with
 211    respect to the file associated with FD.  */
 212 # ifndef __USE_FILE_OFFSET64
 213 extern int posix_fadvise (int __fd, __off_t __offset, __off_t __len,
 214                           int __advise) __THROW;
 215 # else
 216 #  ifdef __REDIRECT_NTH
 217 extern int __REDIRECT_NTH (posix_fadvise, (int __fd, __off64_t __offset,
 218                                            __off64_t __len, int __advise),
 219                            posix_fadvise64);
 220 #  else
 221 #   define posix_fadvise posix_fadvise64
 222 #  endif
 223 # endif
 224 # ifdef __USE_LARGEFILE64
 225 extern int posix_fadvise64 (int __fd, __off64_t __offset, __off64_t __len,
 226                             int __advise) __THROW;
 227 # endif
 228
 229 #endif
 230
 231 #if defined __UCLIBC_HAS_ADVANCED_REALTIME__
 232
 233 /* Reserve storage for the data of the file associated with FD.
 234
 235    This function is a possible cancellation point and therefore not
 236    marked with __THROW.  */
 237 # ifndef __USE_FILE_OFFSET64
 238 extern int posix_fallocate (int __fd, __off_t __offset, __off_t __len);
 239 # else
 240 #  ifdef __REDIRECT
 241 extern int __REDIRECT (posix_fallocate, (int __fd, __off64_t __offset,
 242                                          __off64_t __len),
 243                        posix_fallocate64);
 244 #  else
 245 #   define posix_fallocate posix_fallocate64
 246 #  endif
 247 # endif
 248 # ifdef __USE_LARGEFILE64
 249 extern int posix_fallocate64 (int __fd, __off64_t __offset, __off64_t __len);
 250 # endif
 251 #endif
 252
 253 #if (defined __UCLIBC_LINUX_SPECIFIC__ && defined __USE_GNU) || defined _LIBC
 254 /* Reserve storage for the data of a file associated with FD.  This function
 255    is Linux-specific.  For the portable version, use posix_fallocate().
 256    Unlike the latter, fallocate can operate in different modes.  The default
 257    mode = 0 is equivalent to posix_fallocate().
 258
 259    Note: These declarations are used in posix_fallocate.c and
 260    posix_fallocate64.c, so we expose them internally.
 261  */
 262
 263 /* Flags for fallocate's mode.  */
 264 # define FALLOC_FL_KEEP_SIZE            1 /* Don't extend size of file
 265                                              even if offset + len is
 266                                              greater than file size.  */
 267 # define FALLOC_FL_PUNCH_HOLE           2 /* Create a hole in the file.  */
 268
 269 # ifndef __USE_FILE_OFFSET64
 270 extern int fallocate (int __fd, int __mode, __off_t __offset, __off_t __len);
 271 # else
 272 #  ifdef __REDIRECT
 273 extern int __REDIRECT (fallocate, (int __fd, int __mode, __off64_t __offset,
 274                                    __off64_t __len),
 275                        fallocate64);
 276 #  else
 277 #   define fallocate fallocate64
 278 #  endif
 279 # endif
 280 # ifdef __USE_LARGEFILE64
 281 extern int fallocate64 (int __fd, int __mode, __off64_t __offset, __off64_t __len);
 282 # endif
 283 #endif
 284
 285 #if (defined __UCLIBC_LINUX_SPECIFIC__ && defined __USE_GNU)
 286 struct file_handle {
 287         unsigned handle_bytes;
 288         int handle_type;
 289         unsigned char f_handle[];
 290 };
 291
 292 #define MAX_HANDLE_SZ  128
 293
 294 int name_to_handle_at(int dirfd, const char *pathname,
 295         struct file_handle *handle, int *mount_id, int flags);
 296 int open_by_handle_at(int mount_fd, struct file_handle *handle, int flags);
 297 #endif
 298
 299 #ifdef __USE_GNU
 300 # define F_SETOWN_EX    15      /* Get owner (thread receiving SIGIO).  */
 301 # define F_GETOWN_EX    16      /* Set owner (thread receiving SIGIO).  */
 302 /* Owner types.  */
 303 enum __pid_type
 304   {
 305     F_OWNER_TID = 0,            /* Kernel thread.  */
 306     F_OWNER_PID,                /* Process.  */
 307     F_OWNER_PGRP,               /* Process group.  */
 308     F_OWNER_GID = F_OWNER_PGRP  /* Alternative, obsolete name.  */
 309   };
 310
 311 /* Structure to use with F_GETOWN_EX and F_SETOWN_EX.  */
 312 struct f_owner_ex
 313   {
 314     enum __pid_type type;       /* Owner type of ID.  */
 315     __pid_t pid;                /* ID of owner.  */
 316   };
 317 #endif
 318
 319 __END_DECLS
 320
 321 #endif /* fcntl.h  */