io/fcntl.h

   1 /* Copyright (C) 1991-2014 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 /*
  19  *      POSIX Standard: 6.5 File Control Operations     <fcntl.h>
  20  */
  21
  22 #ifndef _FCNTL_H
  23 #define _FCNTL_H        1
  24
  25 #include <features.h>
  26
  27 /* This must be early so <bits/fcntl.h> can define types winningly.  */
  28 __BEGIN_DECLS
  29
  30 /* Get __mode_t, __dev_t and __off_t  .*/
  31 #include <bits/types.h>
  32
  33 /* Get the definitions of O_*, F_*, FD_*: all the
  34    numbers and flag bits for `open', `fcntl', et al.  */
  35 #include <bits/fcntl.h>
  36
  37 /* POSIX.1-2001 specifies that these types are defined by <fcntl.h>.
  38    Earlier POSIX standards permitted any type ending in `_t' to be defined
  39    by any POSIX header, so we don't conditionalize the definitions here.  */
  40 #ifndef __mode_t_defined
  41 typedef __mode_t mode_t;
  42 # define __mode_t_defined
  43 #endif
  44
  45 #ifndef __off_t_defined
  46 # ifndef __USE_FILE_OFFSET64
  47 typedef __off_t off_t;
  48 # else
  49 typedef __off64_t off_t;
  50 # endif
  51 # define __off_t_defined
  52 #endif
  53
  54 #if defined __USE_LARGEFILE64 && !defined __off64_t_defined
  55 typedef __off64_t off64_t;
  56 # define __off64_t_defined
  57 #endif
  58
  59 #ifndef __pid_t_defined
  60 typedef __pid_t pid_t;
  61 # define __pid_t_defined
  62 #endif
  63
  64 /* For XPG all symbols from <sys/stat.h> should also be available.  */
  65 #if defined __USE_XOPEN || defined __USE_XOPEN2K8
  66 # define __need_timespec
  67 # include <time.h>
  68 # include <bits/stat.h>
  69
  70 # define S_IFMT         __S_IFMT
  71 # define S_IFDIR        __S_IFDIR
  72 # define S_IFCHR        __S_IFCHR
  73 # define S_IFBLK        __S_IFBLK
  74 # define S_IFREG        __S_IFREG
  75 # ifdef __S_IFIFO
  76 #  define S_IFIFO       __S_IFIFO
  77 # endif
  78 # ifdef __S_IFLNK
  79 #  define S_IFLNK       __S_IFLNK
  80 # endif
  81 # if (defined __USE_UNIX98 || defined __USE_XOPEN2K8) && defined __S_IFSOCK
  82 #  define S_IFSOCK      __S_IFSOCK
  83 # endif
  84
  85 /* Protection bits.  */
  86
  87 # define S_ISUID        __S_ISUID       /* Set user ID on execution.  */
  88 # define S_ISGID        __S_ISGID       /* Set group ID on execution.  */
  89
  90 # if defined __USE_MISC || defined __USE_XOPEN
  91 /* Save swapped text after use (sticky bit).  This is pretty well obsolete.  */
  92 #  define S_ISVTX       __S_ISVTX
  93 # endif
  94
  95 # define S_IRUSR        __S_IREAD       /* Read by owner.  */
  96 # define S_IWUSR        __S_IWRITE      /* Write by owner.  */
  97 # define S_IXUSR        __S_IEXEC       /* Execute by owner.  */
  98 /* Read, write, and execute by owner.  */
  99 # define S_IRWXU        (__S_IREAD|__S_IWRITE|__S_IEXEC)
 100
 101 # define S_IRGRP        (S_IRUSR >> 3)  /* Read by group.  */
 102 # define S_IWGRP        (S_IWUSR >> 3)  /* Write by group.  */
 103 # define S_IXGRP        (S_IXUSR >> 3)  /* Execute by group.  */
 104 /* Read, write, and execute by group.  */
 105 # define S_IRWXG        (S_IRWXU >> 3)
 106
 107 # define S_IROTH        (S_IRGRP >> 3)  /* Read by others.  */
 108 # define S_IWOTH        (S_IWGRP >> 3)  /* Write by others.  */
 109 # define S_IXOTH        (S_IXGRP >> 3)  /* Execute by others.  */
 110 /* Read, write, and execute by others.  */
 111 # define S_IRWXO        (S_IRWXG >> 3)
 112 #endif
 113
 114 #ifdef  __USE_MISC
 115 # ifndef R_OK                   /* Verbatim from <unistd.h>.  Ugh.  */
 116 /* Values for the second argument to access.
 117    These may be OR'd together.  */
 118 #  define R_OK  4               /* Test for read permission.  */
 119 #  define W_OK  2               /* Test for write permission.  */
 120 #  define X_OK  1               /* Test for execute permission.  */
 121 #  define F_OK  0               /* Test for existence.  */
 122 # endif
 123 #endif /* Use misc.  */
 124
 125 /* XPG wants the following symbols.   <stdio.h> has the same definitions.  */
 126 #if defined __USE_XOPEN || defined __USE_XOPEN2K8
 127 # define SEEK_SET       0       /* Seek from beginning of file.  */
 128 # define SEEK_CUR       1       /* Seek from current position.  */
 129 # define SEEK_END       2       /* Seek from end of file.  */
 130 #endif  /* XPG */
 131
 132 /* The constants AT_REMOVEDIR and AT_EACCESS have the same value.  AT_EASSESS
 133    is meaningful only to faccessat, while AT_REMOVEDIR is meaningful only to
 134    unlinkat.  The two functions do completely different things and therefore,
 135    the flags can be allowed to overlap.  For example, passing AT_REMOVEDIR to
 136    faccessat would be undefined behavior and thus treating it equivalent to
 137    AT_EACCESS is valid undefined behavior.  */
 138 #ifdef __USE_ATFILE
 139 # define AT_FDCWD               -100    /* Special value used to indicate
 140                                            the *at functions should use the
 141                                            current working directory. */
 142 # define AT_SYMLINK_NOFOLLOW    0x100   /* Do not follow symbolic links.  */
 143 # define AT_REMOVEDIR           0x200   /* Remove directory instead of
 144                                            unlinking file.  */
 145 # define AT_SYMLINK_FOLLOW      0x400   /* Follow symbolic links.  */
 146 # ifdef __USE_GNU
 147 #  define AT_NO_AUTOMOUNT       0x800   /* Suppress terminal automount
 148                                            traversal.  */
 149 #  define AT_EMPTY_PATH         0x1000  /* Allow empty relative pathname.  */
 150 # endif
 151 # define AT_EACCESS             0x200   /* Test access permitted for
 152                                            effective IDs, not real IDs.  */
 153 #endif
 154
 155 /* Do the file control operation described by CMD on FD.
 156    The remaining arguments are interpreted depending on CMD.
 157
 158    This function is a cancellation point and therefore not marked with
 159    __THROW.  */
 160 extern int fcntl (int __fd, int __cmd, ...);
 161
 162 /* Open FILE and return a new file descriptor for it, or -1 on error.
 163    OFLAG determines the type of access used.  If O_CREAT is on OFLAG,
 164    the third argument is taken as a `mode_t', the mode of the created file.
 165
 166    This function is a cancellation point and therefore not marked with
 167    __THROW.  */
 168 #ifndef __USE_FILE_OFFSET64
 169 extern int open (const char *__file, int __oflag, ...) __nonnull ((1));
 170 #else
 171 # ifdef __REDIRECT
 172 extern int __REDIRECT (open, (const char *__file, int __oflag, ...), open64)
 173      __nonnull ((1));
 174 # else
 175 #  define open open64
 176 # endif
 177 #endif
 178 #ifdef __USE_LARGEFILE64
 179 extern int open64 (const char *__file, int __oflag, ...) __nonnull ((1));
 180 #endif
 181
 182 #ifdef __USE_ATFILE
 183 /* Similar to `open' but a relative path name is interpreted relative to
 184    the directory for which FD is a descriptor.
 185
 186    NOTE: some other `openat' implementation support additional functionality
 187    through this interface, especially using the O_XATTR flag.  This is not
 188    yet supported here.
 189
 190    This function is a cancellation point and therefore not marked with
 191    __THROW.  */
 192 # ifndef __USE_FILE_OFFSET64
 193 extern int openat (int __fd, const char *__file, int __oflag, ...)
 194      __nonnull ((2));
 195 # else
 196 #  ifdef __REDIRECT
 197 extern int __REDIRECT (openat, (int __fd, const char *__file, int __oflag,
 198                                 ...), openat64) __nonnull ((2));
 199 #  else
 200 #   define openat openat64
 201 #  endif
 202 # endif
 203 # ifdef __USE_LARGEFILE64
 204 extern int openat64 (int __fd, const char *__file, int __oflag, ...)
 205      __nonnull ((2));
 206 # endif
 207 #endif
 208
 209 /* Create and open FILE, with mode MODE.  This takes an `int' MODE
 210    argument because that is what `mode_t' will be widened to.
 211
 212    This function is a cancellation point and therefore not marked with
 213    __THROW.  */
 214 #ifndef __USE_FILE_OFFSET64
 215 extern int creat (const char *__file, mode_t __mode) __nonnull ((1));
 216 #else
 217 # ifdef __REDIRECT
 218 extern int __REDIRECT (creat, (const char *__file, mode_t __mode),
 219                        creat64) __nonnull ((1));
 220 # else
 221 #  define creat creat64
 222 # endif
 223 #endif
 224 #ifdef __USE_LARGEFILE64
 225 extern int creat64 (const char *__file, mode_t __mode) __nonnull ((1));
 226 #endif
 227
 228 #if !defined F_LOCK && (defined __USE_MISC || (defined __USE_XOPEN_EXTENDED \
 229                                                && !defined __USE_POSIX))
 230 /* NOTE: These declarations also appear in <unistd.h>; be sure to keep both
 231    files consistent.  Some systems have them there and some here, and some
 232    software depends on the macros being defined without including both.  */
 233
 234 /* `lockf' is a simpler interface to the locking facilities of `fcntl'.
 235    LEN is always relative to the current file position.
 236    The CMD argument is one of the following.  */
 237
 238 # define F_ULOCK 0      /* Unlock a previously locked region.  */
 239 # define F_LOCK  1      /* Lock a region for exclusive use.  */
 240 # define F_TLOCK 2      /* Test and lock a region for exclusive use.  */
 241 # define F_TEST  3      /* Test a region for other processes locks.  */
 242
 243 # ifndef __USE_FILE_OFFSET64
 244 extern int lockf (int __fd, int __cmd, off_t __len);
 245 # else
 246 #  ifdef __REDIRECT
 247 extern int __REDIRECT (lockf, (int __fd, int __cmd, __off64_t __len), lockf64);
 248 #  else
 249 #   define lockf lockf64
 250 #  endif
 251 # endif
 252 # ifdef __USE_LARGEFILE64
 253 extern int lockf64 (int __fd, int __cmd, off64_t __len);
 254 # endif
 255 #endif
 256
 257 #ifdef __USE_XOPEN2K
 258 /* Advice the system about the expected behaviour of the application with
 259    respect to the file associated with FD.  */
 260 # ifndef __USE_FILE_OFFSET64
 261 extern int posix_fadvise (int __fd, off_t __offset, off_t __len,
 262                           int __advise) __THROW;
 263 # else
 264  # ifdef __REDIRECT_NTH
 265 extern int __REDIRECT_NTH (posix_fadvise, (int __fd, __off64_t __offset,
 266                                            __off64_t __len, int __advise),
 267                            posix_fadvise64);
 268 #  else
 269 #   define posix_fadvise posix_fadvise64
 270 #  endif
 271 # endif
 272 # ifdef __USE_LARGEFILE64
 273 extern int posix_fadvise64 (int __fd, off64_t __offset, off64_t __len,
 274                             int __advise) __THROW;
 275 # endif
 276
 277
 278 /* Reserve storage for the data of the file associated with FD.
 279
 280    This function is a possible cancellation point and therefore not
 281    marked with __THROW.  */
 282 # ifndef __USE_FILE_OFFSET64
 283 extern int posix_fallocate (int __fd, off_t __offset, off_t __len);
 284 # else
 285  # ifdef __REDIRECT
 286 extern int __REDIRECT (posix_fallocate, (int __fd, __off64_t __offset,
 287                                          __off64_t __len),
 288                        posix_fallocate64);
 289 #  else
 290 #   define posix_fallocate posix_fallocate64
 291 #  endif
 292 # endif
 293 # ifdef __USE_LARGEFILE64
 294 extern int posix_fallocate64 (int __fd, off64_t __offset, off64_t __len);
 295 # endif
 296 #endif
 297
 298
 299 /* Define some inlines helping to catch common problems.  */
 300 #if __USE_FORTIFY_LEVEL > 0 && defined __fortify_function \
 301     && defined __va_arg_pack_len
 302 # include <bits/fcntl2.h>
 303 #endif
 304
 305 __END_DECLS
 306
 307 #endif /* fcntl.h  */