io/fcntl.h

   1 /* Copyright (C) 1991,1992,1994-2001,2003,2004,2005,2006,2007,2009,2010,2011
   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, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 /*
  21  *      POSIX Standard: 6.5 File Control Operations     <fcntl.h>
  22  */
  23
  24 #ifndef _FCNTL_H
  25 #define _FCNTL_H        1
  26
  27 #include <features.h>
  28
  29 /* This must be early so <bits/fcntl.h> can define types winningly.  */
  30 __BEGIN_DECLS
  31
  32 /* Get the definitions of O_*, F_*, FD_*: all the
  33    numbers and flag bits for `open', `fcntl', et al.  */
  34 #include <bits/fcntl.h>
  35
  36 /* For XPG all symbols from <sys/stat.h> should also be available.  */
  37 #if defined __USE_XOPEN || defined __USE_XOPEN2K8
  38 # include <bits/types.h>         /* For __mode_t and __dev_t.  */
  39 # define __need_timespec
  40 # include <time.h>
  41 # include <bits/stat.h>
  42
  43 # define S_IFMT         __S_IFMT
  44 # define S_IFDIR        __S_IFDIR
  45 # define S_IFCHR        __S_IFCHR
  46 # define S_IFBLK        __S_IFBLK
  47 # define S_IFREG        __S_IFREG
  48 # ifdef __S_IFIFO
  49 #  define S_IFIFO       __S_IFIFO
  50 # endif
  51 # ifdef __S_IFLNK
  52 #  define S_IFLNK       __S_IFLNK
  53 # endif
  54 # if (defined __USE_UNIX98 || defined __USE_XOPEN2K8) && defined __S_IFSOCK
  55 #  define S_IFSOCK      __S_IFSOCK
  56 # endif
  57
  58 /* Protection bits.  */
  59
  60 # define S_ISUID        __S_ISUID       /* Set user ID on execution.  */
  61 # define S_ISGID        __S_ISGID       /* Set group ID on execution.  */
  62
  63 # if defined __USE_BSD || defined __USE_MISC || defined __USE_XOPEN
  64 /* Save swapped text after use (sticky bit).  This is pretty well obsolete.  */
  65 #  define S_ISVTX       __S_ISVTX
  66 # endif
  67
  68 # define S_IRUSR        __S_IREAD       /* Read by owner.  */
  69 # define S_IWUSR        __S_IWRITE      /* Write by owner.  */
  70 # define S_IXUSR        __S_IEXEC       /* Execute by owner.  */
  71 /* Read, write, and execute by owner.  */
  72 # define S_IRWXU        (__S_IREAD|__S_IWRITE|__S_IEXEC)
  73
  74 # define S_IRGRP        (S_IRUSR >> 3)  /* Read by group.  */
  75 # define S_IWGRP        (S_IWUSR >> 3)  /* Write by group.  */
  76 # define S_IXGRP        (S_IXUSR >> 3)  /* Execute by group.  */
  77 /* Read, write, and execute by group.  */
  78 # define S_IRWXG        (S_IRWXU >> 3)
  79
  80 # define S_IROTH        (S_IRGRP >> 3)  /* Read by others.  */
  81 # define S_IWOTH        (S_IWGRP >> 3)  /* Write by others.  */
  82 # define S_IXOTH        (S_IXGRP >> 3)  /* Execute by others.  */
  83 /* Read, write, and execute by others.  */
  84 # define S_IRWXO        (S_IRWXG >> 3)
  85 #endif
  86
  87 #ifdef  __USE_MISC
  88 # ifndef R_OK                   /* Verbatim from <unistd.h>.  Ugh.  */
  89 /* Values for the second argument to access.
  90    These may be OR'd together.  */
  91 #  define R_OK  4               /* Test for read permission.  */
  92 #  define W_OK  2               /* Test for write permission.  */
  93 #  define X_OK  1               /* Test for execute permission.  */
  94 #  define F_OK  0               /* Test for existence.  */
  95 # endif
  96 #endif /* Use misc.  */
  97
  98 /* XPG wants the following symbols.   <stdio.h> has the same definitions.  */
  99 #if defined __USE_XOPEN || defined __USE_XOPEN2K8
 100 # define SEEK_SET       0       /* Seek from beginning of file.  */
 101 # define SEEK_CUR       1       /* Seek from current position.  */
 102 # define SEEK_END       2       /* Seek from end of file.  */
 103 #endif  /* XPG */
 104
 105 #ifdef __USE_ATFILE
 106 # define AT_FDCWD               -100    /* Special value used to indicate
 107                                            the *at functions should use the
 108                                            current working directory. */
 109 # define AT_SYMLINK_NOFOLLOW    0x100   /* Do not follow symbolic links.  */
 110 # define AT_REMOVEDIR           0x200   /* Remove directory instead of
 111                                            unlinking file.  */
 112 # define AT_SYMLINK_FOLLOW      0x400   /* Follow symbolic links.  */
 113 # define AT_NO_AUTOMOUNT        0x800   /* Suppress terminal automount
 114                                            traversal.  */
 115 # define AT_EACCESS             0x200   /* Test access permitted for
 116                                            effective IDs, not real IDs.  */
 117 #endif
 118
 119 /* Do the file control operation described by CMD on FD.
 120    The remaining arguments are interpreted depending on CMD.
 121
 122    This function is a cancellation point and therefore not marked with
 123    __THROW.  */
 124 extern int fcntl (int __fd, int __cmd, ...);
 125
 126 /* Open FILE and return a new file descriptor for it, or -1 on error.
 127    OFLAG determines the type of access used.  If O_CREAT is on OFLAG,
 128    the third argument is taken as a `mode_t', the mode of the created file.
 129
 130    This function is a cancellation point and therefore not marked with
 131    __THROW.  */
 132 #ifndef __USE_FILE_OFFSET64
 133 extern int open (__const char *__file, int __oflag, ...) __nonnull ((1));
 134 #else
 135 # ifdef __REDIRECT
 136 extern int __REDIRECT (open, (__const char *__file, int __oflag, ...), open64)
 137      __nonnull ((1));
 138 # else
 139 #  define open open64
 140 # endif
 141 #endif
 142 #ifdef __USE_LARGEFILE64
 143 extern int open64 (__const char *__file, int __oflag, ...) __nonnull ((1));
 144 #endif
 145
 146 #ifdef __USE_ATFILE
 147 /* Similar to `open' but a relative path name is interpreted relative to
 148    the directory for which FD is a descriptor.
 149
 150    NOTE: some other `openat' implementation support additional functionality
 151    through this interface, especially using the O_XATTR flag.  This is not
 152    yet supported here.
 153
 154    This function is a cancellation point and therefore not marked with
 155    __THROW.  */
 156 # ifndef __USE_FILE_OFFSET64
 157 extern int openat (int __fd, __const char *__file, int __oflag, ...)
 158      __nonnull ((2));
 159 # else
 160 #  ifdef __REDIRECT
 161 extern int __REDIRECT (openat, (int __fd, __const char *__file, int __oflag,
 162                                 ...), openat64) __nonnull ((2));
 163 #  else
 164 #   define openat openat64
 165 #  endif
 166 # endif
 167 # ifdef __USE_LARGEFILE64
 168 extern int openat64 (int __fd, __const char *__file, int __oflag, ...)
 169      __nonnull ((2));
 170 # endif
 171 #endif
 172
 173 /* Create and open FILE, with mode MODE.  This takes an `int' MODE
 174    argument because that is what `mode_t' will be widened to.
 175
 176    This function is a cancellation point and therefore not marked with
 177    __THROW.  */
 178 #ifndef __USE_FILE_OFFSET64
 179 extern int creat (__const char *__file, __mode_t __mode) __nonnull ((1));
 180 #else
 181 # ifdef __REDIRECT
 182 extern int __REDIRECT (creat, (__const char *__file, __mode_t __mode),
 183                        creat64) __nonnull ((1));
 184 # else
 185 #  define creat creat64
 186 # endif
 187 #endif
 188 #ifdef __USE_LARGEFILE64
 189 extern int creat64 (__const char *__file, __mode_t __mode) __nonnull ((1));
 190 #endif
 191
 192 #if !defined F_LOCK && (defined __USE_MISC || (defined __USE_XOPEN_EXTENDED \
 193                                                && !defined __USE_POSIX))
 194 /* NOTE: These declarations also appear in <unistd.h>; be sure to keep both
 195    files consistent.  Some systems have them there and some here, and some
 196    software depends on the macros being defined without including both.  */
 197
 198 /* `lockf' is a simpler interface to the locking facilities of `fcntl'.
 199    LEN is always relative to the current file position.
 200    The CMD argument is one of the following.  */
 201
 202 # define F_ULOCK 0      /* Unlock a previously locked region.  */
 203 # define F_LOCK  1      /* Lock a region for exclusive use.  */
 204 # define F_TLOCK 2      /* Test and lock a region for exclusive use.  */
 205 # define F_TEST  3      /* Test a region for other processes locks.  */
 206
 207 # ifndef __USE_FILE_OFFSET64
 208 extern int lockf (int __fd, int __cmd, __off_t __len);
 209 # else
 210 #  ifdef __REDIRECT
 211 extern int __REDIRECT (lockf, (int __fd, int __cmd, __off64_t __len), lockf64);
 212 #  else
 213 #   define lockf lockf64
 214 #  endif
 215 # endif
 216 # ifdef __USE_LARGEFILE64
 217 extern int lockf64 (int __fd, int __cmd, __off64_t __len);
 218 # endif
 219 #endif
 220
 221 #ifdef __USE_XOPEN2K
 222 /* Advice the system about the expected behaviour of the application with
 223    respect to the file associated with FD.  */
 224 # ifndef __USE_FILE_OFFSET64
 225 extern int posix_fadvise (int __fd, __off_t __offset, __off_t __len,
 226                           int __advise) __THROW;
 227 # else
 228  # ifdef __REDIRECT_NTH
 229 extern int __REDIRECT_NTH (posix_fadvise, (int __fd, __off64_t __offset,
 230                                            __off64_t __len, int __advise),
 231                            posix_fadvise64);
 232 #  else
 233 #   define posix_fadvise posix_fadvise64
 234 #  endif
 235 # endif
 236 # ifdef __USE_LARGEFILE64
 237 extern int posix_fadvise64 (int __fd, __off64_t __offset, __off64_t __len,
 238                             int __advise) __THROW;
 239 # endif
 240
 241
 242 /* Reserve storage for the data of the file associated with FD.
 243
 244    This function is a possible cancellation points and therefore not
 245    marked with __THROW.  */
 246 # ifndef __USE_FILE_OFFSET64
 247 extern int posix_fallocate (int __fd, __off_t __offset, __off_t __len);
 248 # else
 249  # ifdef __REDIRECT
 250 extern int __REDIRECT (posix_fallocate, (int __fd, __off64_t __offset,
 251                                          __off64_t __len),
 252                        posix_fallocate64);
 253 #  else
 254 #   define posix_fallocate posix_fallocate64
 255 #  endif
 256 # endif
 257 # ifdef __USE_LARGEFILE64
 258 extern int posix_fallocate64 (int __fd, __off64_t __offset, __off64_t __len);
 259 # endif
 260 #endif
 261
 262
 263 /* Define some inlines helping to catch common problems.  */
 264 #if __USE_FORTIFY_LEVEL > 0 && defined __extern_always_inline \
 265     && defined __va_arg_pack_len
 266 # include <bits/fcntl2.h>
 267 #endif
 268
 269 __END_DECLS
 270
 271 #endif /* fcntl.h  */