bits/mman.h

   1 /* Definitions for BSD-style memory management.
   2    Copyright (C) 1994-2023 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    <https://www.gnu.org/licenses/>.  */
  18
  19 /* These are the bits used by 4.4 BSD and its derivatives.  On systems
  20    (such as GNU) where these facilities are not system services but can be
  21    emulated in the C library, these are the definitions we emulate.  */
  22
  23 #ifndef _SYS_MMAN_H
  24 # error "Never use <bits/mman.h> directly; include <sys/mman.h> instead."
  25 #endif
  26
  27 /* Protections are chosen from these bits, OR'd together.  The
  28    implementation does not necessarily support PROT_EXEC or PROT_WRITE
  29    without PROT_READ.  The only guarantees are that no writing will be
  30    allowed without PROT_WRITE and no access will be allowed for PROT_NONE. */
  31
  32 #define PROT_NONE        0x00   /* No access.  */
  33 #define PROT_READ        0x04   /* Pages can be read.  */
  34 #define PROT_WRITE       0x02   /* Pages can be written.  */
  35 #define PROT_EXEC        0x01   /* Pages can be executed.  */
  36
  37 /* Flags contain mapping type, sharing type and options.  */
  38
  39 /* Mapping type (must choose one and only one of these).  */
  40 #define MAP_FILE         0x0001 /* Mapped from a file or device.  */
  41 #define MAP_ANON         0x0002 /* Allocated from anonymous virtual memory.  */
  42 #define MAP_TYPE         0x000f /* Mask for type field.  */
  43 #define MAP_ANONYMOUS    MAP_ANON /* Linux name. */
  44
  45 /* Sharing types (must choose one and only one of these).  */
  46 #define MAP_COPY         0x0020 /* Virtual copy of region at mapping time.  */
  47 #define MAP_SHARED       0x0010 /* Share changes.  */
  48 #define MAP_PRIVATE      0x0000 /* Changes private; copy pages on write.  */
  49
  50 /* Other flags.  */
  51 #define MAP_FIXED        0x0100 /* Map address must be exactly as requested. */
  52 #define MAP_NOEXTEND     0x0200 /* For MAP_FILE, don't change file size.  */
  53 #define MAP_HASSEMPHORE 0x0400  /* Region may contain semaphores.  */
  54 #define MAP_INHERIT      0x0800 /* Region is retained after exec.  */
  55
  56 /* Advice to `madvise'.  */
  57 #ifdef __USE_MISC
  58 # define MADV_NORMAL     0      /* No further special treatment.  */
  59 # define MADV_RANDOM     1      /* Expect random page references.  */
  60 # define MADV_SEQUENTIAL 2      /* Expect sequential page references.  */
  61 # define MADV_WILLNEED   3      /* Will need these pages.  */
  62 # define MADV_DONTNEED   4      /* Don't need these pages.  */
  63 #endif
  64
  65 /* The POSIX people had to invent similar names for the same things.  */
  66 #ifdef __USE_XOPEN2K
  67 # define POSIX_MADV_NORMAL      0 /* No further special treatment.  */
  68 # define POSIX_MADV_RANDOM      1 /* Expect random page references.  */
  69 # define POSIX_MADV_SEQUENTIAL  2 /* Expect sequential page references.  */
  70 # define POSIX_MADV_WILLNEED    3 /* Will need these pages.  */
  71 # define POSIX_MADV_DONTNEED    4 /* Don't need these pages.  */
  72 #endif
  73
  74 /* Flags to `msync'.  */
  75 #define MS_ASYNC        1               /* Sync memory asynchronously.  */
  76 #define MS_SYNC         0               /* Synchronous memory sync.  */
  77 #define MS_INVALIDATE   2               /* Invalidate the caches.  */
  78
  79 /* Flags for `mremap'.  */
  80 #ifdef __USE_GNU
  81 # define MREMAP_MAYMOVE 1               /* Mapping address may change.  */
  82 # define MREMAP_FIXED   2               /* Fifth argument sets new address.  */
  83 #endif
  84
  85 /* Flags for `mlockall' (can be OR'd together).  */
  86 #define MCL_CURRENT     1               /* Lock all currently mapped pages.  */
  87 #define MCL_FUTURE      2               /* Lock all additions to address
  88                                            space.  */