sysdeps/gnu/bits/shm.h

   1 /* Copyright (C) 1995-2020 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    <https://www.gnu.org/licenses/>.  */
  17
  18 #ifndef _SYS_SHM_H
  19 # error "Never include <bits/shm.h> directly; use <sys/shm.h> instead."
  20 #endif
  21
  22 #include <bits/types.h>
  23 #include <bits/ipctypes.h>
  24
  25 /* Permission flag for shmget.  */
  26 #define SHM_R           0400            /* or S_IRUGO from <linux/stat.h> */
  27 #define SHM_W           0200            /* or S_IWUGO from <linux/stat.h> */
  28
  29 /* Flags for `shmat'.  */
  30 #define SHM_RDONLY      010000          /* attach read-only else read-write */
  31 #define SHM_RND         020000          /* round attach address to SHMLBA */
  32 #define SHM_REMAP       040000          /* take-over region on attach */
  33
  34 /* Commands for `shmctl'.  */
  35 #define SHM_LOCK        11              /* lock segment (root only) */
  36 #define SHM_UNLOCK      12              /* unlock segment (root only) */
  37
  38 __BEGIN_DECLS
  39
  40 /* Segment low boundary address multiple.  */
  41 #define SHMLBA          (__getpagesize ())
  42 extern int __getpagesize (void) __THROW __attribute__ ((__const__));
  43
  44
  45 /* Type to count number of attaches.  */
  46 typedef unsigned short int shmatt_t;
  47
  48 /* Data structure describing a shared memory segment.  */
  49 struct shmid_ds
  50   {
  51     struct ipc_perm shm_perm;           /* operation permission struct */
  52     size_t shm_segsz;                   /* size of segment in bytes */
  53     __time_t shm_atime;                 /* time of last shmat() */
  54     __time_t shm_dtime;                 /* time of last shmdt() */
  55     __time_t shm_ctime;                 /* time of last change by shmctl() */
  56     __ipc_pid_t shm_cpid;               /* pid of creator */
  57     __ipc_pid_t shm_lpid;               /* pid of last shmop */
  58     shmatt_t shm_nattch;                /* number of current attaches */
  59     unsigned short int __shm_npages;    /* size of segment (pages) */
  60     unsigned long int *__shm_pages;     /* array of ptrs to frames -> SHMMAX */
  61     struct __vm_area_struct *__attaches;        /* descriptors for attaches */
  62   };
  63
  64 #ifdef __USE_MISC
  65
  66 /* ipcs ctl commands */
  67 # define SHM_STAT       13
  68 # define SHM_INFO       14
  69
  70 /* shm_mode upper byte flags */
  71 # define SHM_DEST       01000   /* segment will be destroyed on last detach */
  72 # define SHM_LOCKED     02000   /* segment will not be swapped */
  73
  74 struct  shminfo
  75   {
  76     int shmmax;
  77     int shmmin;
  78     int shmmni;
  79     int shmseg;
  80     int shmall;
  81   };
  82
  83 struct shm_info
  84   {
  85     int used_ids;
  86     unsigned long int shm_tot;  /* total allocated shm */
  87     unsigned long int shm_rss;  /* total resident shm */
  88     unsigned long int shm_swp;  /* total swapped shm */
  89     unsigned long int swap_attempts;
  90     unsigned long int swap_successes;
  91   };
  92
  93 #endif /* __USE_MISC */
  94
  95 __END_DECLS